Patent Publication Number: US-11022578-B2

Title: Lateral flow assay with controlled conjugate time and controlled flow time

Description:
CLAIM OF BENEFIT TO PRIOR APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 16/986,175, filed on Aug. 5, 2020. U.S. patent application Ser. No. 16/986,175 is a continuation of U.S. patent application Ser. No. 16/698,788, filed on Nov. 27, 2019, issued as U.S. Pat. No. 10,739,297. U.S. patent application Ser. No. 16/698,788 claims the benefit of U.S. Provisional Patent Application Ser. No. 62/772,525, filed on Nov. 28, 2018. The contents of U.S. patent application Ser. No. 16/986,175, U.S. patent application Ser. No. 16/698,788, issued as U.S. Pat. No. 10,739,297, and Provisional Patent Application 62/772,525 are hereby incorporated by reference. 
    
    
     BACKGROUND 
     Lateral flow assays (LFAs) are devices that are used to detect the presence (or absence) of a target analyte in a sample fluid without the need for specialized equipment. The lateral flow assays are widely used for medical diagnostics for point of care testing, home testing, or laboratory use. 
     A lateral flow assay typically includes a series of capillary pads for transporting fluid. A sandwich assay format may be used for detecting analytes that have at least two binding sites to bind to an antibody. A sample pad is used to receive a quantity of fluid (referred to as the sample fluid) and transport the sample fluid to an adjacent conjugate pad. The conjugate pad contains a solubilized antibody labeled with a detector such as colloidal gold nanoparticles. The antibody is specific to a certain analyte which is the target of interest in the sample fluid. As the sample fluid flows through the conjugate pad, the analyte (if any) in the sample fluid binds with the labeled antibody on the conjugate pad and forms an immunocomplex. 
     The immunocomplex then flows from the conjugate pad into an adjacent membrane (or membrane pad). The membrane has a test area, or test line, that contains an immobilized unlabeled antibody. As the immunocomplex moves over the test area, the immunocomplex binds with the immobilized antibody on the test area, resulting in a colored test line. When the sample fluid does not include the target analyte, no immunocomplex is formed on the conjugate pad and no immunocomplex binds with the immobilized antibody on the test area. As a result, the test line does not change color. 
     A lateral flow assay may also include a control line in the membrane. In a sandwich assay format, the control line may contain an immobilized antibody that binds to the free antibodies labeled with the detector resulting in a colored control line, which confirms that the test has operated correctly regardless of whether or not the target analyte has been present in the sample. 
     A competitive assay format may be used for detecting analytes that cannot simultaneously bind to two antibodies. The sample pad and the conjugate pad in a competitive assay format are similar to the sample pad and the conjugate pad in the sandwich assay format. In the competitive assay format, the test line contains immobilized analyte molecules. 
     If the sample liquid does not contain the analyte, the labeled antibody flows from the conjugate pad into the test line and binds to the analyte at the test line, resulting in a colored test line that indicates the lack of the target analyte in the sample liquid. If, on the other hand, the target analyte is present in the sample liquid, the analyte binds to the labeled antibodies on the conjugate pad and prevents the labeled antibody to bind to the analyte at the test line, resulting in the lack of color on the test line. In a competitive assay format, the control line may contain an immobilized analyte that binds to the free antibodies labeled with the detector resulting in a colored control line, which confirms that the test has operated correctly regardless of whether or not the target analyte has been present in the sample. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various embodiments of the present lateral flow assay with controlled conjugate time and controlled flow time now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious lateral flow assay with controlled conjugate time and controlled flow time shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts: 
         FIG. 1  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 2  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cross section of the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure; 
         FIG. 3  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing the removal of the barrier, according to various aspects of the present disclosure; 
         FIG. 4  is an upper front perspective of one example embodiment of a physical barrier with a piece of magnet attached to it, according to various aspects of the present disclosure; 
         FIG. 5  is a functional block diagram illustrating one example embodiment of a linear actuator that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 6  is a functional block diagram illustrating one example embodiment of a solenoid that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 7  is a functional block diagram illustrating one example embodiment of an electromagnet that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 8  is an upper front perspective of one example embodiment of a physical barrier that includes a hole, according to various aspects of the present disclosure; 
         FIG. 9  is a functional block diagram illustrating one example embodiment of the linear moving shaft of  FIG. 5  with a hook that is used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 10  is an upper front perspective of one example embodiment of a physical barrier that includes a groove for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 11  is a flowchart illustrating an example process for pulling out a barrier that separates the labeling and capture zones of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 12  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device that includes a permanent gap in the backing card and/or the cartridge bed to prevent the leaking of the fluid material from under the conjugate pad into the membrane while the barrier is in place, according to various aspects of the present disclosure; 
         FIG. 13  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device with a permanent gap in the backing card and/or the cartridge bed, showing the removal of the barrier, according to various aspects of the present disclosure; 
         FIG. 14  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cartridge inside the device&#39;s housing, according to various aspects of the present disclosure; 
         FIG. 15  is a front elevation view of the lateral flow assay device of  FIG. 14 , according to various aspects of the present disclosure; 
         FIG. 16  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device with multiple barrier zones, according to various aspects of the present disclosure; 
         FIG. 17  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cross section of the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure; 
         FIG. 18  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing the removal of multiple barriers, according to various aspects of the present disclosure; 
         FIG. 19  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device that includes one or more permanent gaps in the backing card and/or the cartridge bed to prevent the leaking of the fluid material while the corresponding barrier(s) is/are in place, according to various aspects of the present disclosure; 
         FIG. 20  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device that has a gap separating the labelling zone and the capture zone, according to various aspects of the present disclosure; 
         FIG. 21  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cross section of the lateral flow assay device&#39;s housing before and after removing a gap between the labeling zone and the capture zone, according to various aspects of the present disclosure; 
         FIG. 22  is a top elevational view of the housing of the lateral flow assay device of  FIG. 21 , according to various aspects of the present disclosure; 
         FIG. 23  is a front elevational view of one example embodiment of a portion of a lateral flow assay device that may use one or more posts or pillars to create a removable gap between the conjugate pad and the membrane, according to various aspects of the present disclosure; 
         FIG. 24  is a top elevational view of one example embodiment of the lateral flow assay device of  FIG. 23 , according to various aspects of the present disclosure; 
         FIG. 25  is a front elevational view of one example embodiment of a portion of a lateral flow assay device after a gap between the conjugate pad and the membrane is removed, according to various aspects of the present disclosure; 
         FIG. 26  is a flowchart illustrating an example process for removing a gap that separates the labeling and capture zones of a lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 27  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device with multiple gaps separating different components of the lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 28  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cross section of the lateral flow assay device&#39;s housing before and after removing multiple gaps, according to various aspects of the present disclosure; 
         FIG. 29  is a front elevational view of one example embodiment of a portion of a lateral flow assay device that may use multiple posts or pillars to create removable gaps between different components of the lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 30  is a top elevational view of one example embodiment of the lateral flow assay device of  FIG. 29 , according to various aspects of the present disclosure; 
         FIG. 31  is a front elevational view of one example embodiment of a portion of a lateral flow assay device after several gaps are removed between different components of the lateral flow assay device, according to various aspects of the present disclosure; 
         FIG. 32  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that removes gaps by a spring mechanism, according to various aspects of the present disclosure; 
         FIG. 33  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 32 , according to various aspects of the present disclosure; 
         FIG. 34  illustrates an example of a number of curves generated for a particular membrane paper material for a range of connection time and disconnection time of the conjugate pad and the membrane, according to various aspects of the present disclosure; 
         FIG. 35  illustrates an example of selecting the connection and disconnection times of the conjugate and membrane pads for a specified flow time, according to various aspects of the present disclosure; 
         FIG. 36  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a spring mechanism and an electromagnet, according to various aspects of the present disclosure; 
         FIG. 37  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 36 , according to various aspects of the present disclosure; 
         FIG. 38  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a piezoelectric actuator, according to various aspects of the present disclosure; 
         FIG. 39  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by magnets and electromagnets, according to various aspects of the present disclosure; 
         FIG. 40  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 39 , according to various aspects of the present disclosure; 
         FIG. 41  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by magnets and electromagnets that are positioned over the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure; 
         FIG. 42  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 41 , according to various aspects of the present disclosure; 
         FIG. 43  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by moving a portion of the membrane with a spring mechanism, according to various aspects of the present disclosure; 
         FIG. 44  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a piezoelectric actuator that moves a portion of the membrane, according to various aspects of the present disclosure; 
         FIG. 45  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a spring mechanism and an electromagnet that moves a portion of the membrane, according to various aspects of the present disclosure; 
         FIG. 46  is a front elevation view of one example embodiment of a portion of a lateral flow assay device that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a magnet and an electromagnet that moves a portion of the membrane, according to various aspects of the present disclosure; and 
         FIG. 47  conceptually illustrates an electronic system with which some embodiments of the invention are implemented. 
     
    
    
     DETAILED DESCRIPTION 
     One aspect of the present embodiments includes the realization that some analytes may require a long binding time, also referred to as conjugate time, in order to bind with the labeled antibody on the conjugate pad to form an immunocomplex. It may also be necessary to have a long binding time for the immunocomplex that flows onto the test/control membrane pad to bind to the test line and control line on the membrane pad. The time it takes for the immunocomplex fluid to flow from one end of the membrane pad to the other end is referred to as flow time. 
     It may also be desirable to precisely control the conjugate time for certain types of tests. In a lateral flow assay, the fluid flows laterally from the sample pad into the conjugate pad and from the conjugate pad into the membrane through capillary action. The capillary flow rate depends on the material used (e.g., what the material is made of, the porosity of the material, the grade of the material, etc.) to make the sample pad, the conjugate pad, and the membrane. The time allowed for the binding between the analyte and the labeled antibody on the conjugate pad (conjugate time), or the time allowed for the immunocomplex fluid to travel through the membrane pad over the test line and the control line (flow time), therefore, depends on the length and the type of material used for the conjugate pad and the membrane pad respectively. 
     Controlling the conjugate time and the flow time based on the length and the type of material used for the conjugate pad and the membrane, however, suffers from several drawbacks. Selecting different types of material for the conjugate pad and the membrane would typically provide a capillary flow rate that ranges from approximately 60 seconds per centimeter (cm) to approximately 10 seconds per cm. As the required conjugate time for a test increases, the length of the conjugate pad has to increase. For example, a conjugate time of one hour may require a conjugate pad (even when the materials with the slowest flow rate are used), that is too long to be practical to use in a handheld or portable lateral flow assay due to the length of the conjugate pad, as well as the amount of sample that may be required. In addition, the capillary flow rate may be difficult to estimate and may vary among different specimens of the same type and the same brand of conjugate pad. Accordingly, a precise conjugate time or flow time may not be achievable even when a shorter conjugate time and/or a shorter flow time is required. 
     Some of the present embodiments solve the aforementioned problems by placing a removable physical barrier between the conjugate pad and the membrane. After the desired conjugate time is achieved, the barrier may be removed to allow the sample fluid to flow from the conjugate pad into the membrane. The barrier may be made of a material (e.g., plastic) which blocks the sample fluid from flowing from conjugate pad into the membrane. The barrier material is selected from material that do not react with the sample fluid. 
     In some of the present embodiments, a solenoid, an electromagnet, a servo (also referred to as a servo motor or servomotor), or a linear actuator may be used to remove the barrier after a specific amount of time from the start of the test. For example, at the start of the assay test, a timer may be set to provide a desired conjugate time. After the timer is expired, a signal may be generated to cause the solenoid, the electromagnet, the servo, or the linear actuator to remove (e.g., by a pulling action) the barrier from between the conjugate pad and the membrane. In some of the present embodiments, the barrier may be attached to a magnet or may include a hole, a groove, and/or a string to facilitate the barrier removal. 
     In some of the present embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of the lateral flow assay device. In other embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of a separate non-disposable device that couples with the lateral flow assay during the testing. In some of the present embodiments, the lateral flow assay device may include a housing that may apply pressure to the conjugate pad, the membrane pad, or both. The pressure may facilitate the conjugate pad and the membrane touching each other after the barrier is removed. 
     Some of the present embodiments may include a removable physical barrier to prevent the sample fluid to flow from the test line towards the control line and the wicking pad. After a desired time is achieved for the immobilized molecules at the test line to bind with the fluid material, the barrier may be removed to allow the sample fluid to flow from the test line towards the control line and the wicking pad. Some of the present embodiments may include a removable physical barrier to prevent the sample fluid to flow from the control line towards the wicking pad. After a desired time is achieved for the immobilized molecules at the control line to bind with the fluid material, the barrier may be removed to allow the fluid material to flow from the control line towards the wicking pad. Some of the present embodiments may include more than of the aforementioned three barriers. 
     The lateral flow assay device may include a replaceable cartridge that may be intended for single use. The lateral flow assay device may include a cartridge bed for holding the cartridge in place. The lateral flow assay device may include a backing card that is used to assemble different portions of the sample receiving zone. In some embodiments, each of the sample, conjugate, membrane, and wicking pads may have a separate backing card. Depending on the type of material used for the pads and the backing card, and/or the way the pads are placed on the cartridge bed, even when a physical barrier is in place, some of fluid material may leak from under the pads that are on either side of the barrier. To prevent such a leak, some embodiments may include a permanent gap in the cartridge bed and/or in the backing card in order to prevent the fluid material to leak from under a pad on one side of a barrier to a pad on the other side of the barrier while the barrier is in place. Once the barrier is removed, the fluid may flow freely in the direction of the flow path. 
     In some embodiments, the barrier may not be pulled out of the cartridge at once. Instead, the barrier between the conjugate pad and the membrane may be partially pulled out and then pushed back several times in order to repeatedly bring the conjugate pad and the membrane in touch with each other and then separate them from each other. Repeatedly connecting and disconnecting the conjugate pad and the membrane may be used to control the flow of fluid material from the conjugate pad into the membrane, which in turns control the flow time over the membrane. 
     The number of times the barrier is pulled out and pushed back into the cartridge, the duration that the barrier stays in or out of the cartridge, and the time between the pulling and pushing actions may control the amount of contact between the conjugate pad and the membrane. The amount of contact between the conjugate pad and the membrane may in turn be used to control the flow time (the time it would take for the fluid material to travel the membrane length over the test line and the control line and reach the wicking pad). A similar technique may be used to partially pull out and then push back the barrier that prevents the flow of the fluid material from the test line towards the control line and/or the barrier that controls the flow of the fluid material from the control line towards the wicking pad. 
     Some of the present embodiments may place a gap (instead of a physical barrier) between the conjugate pad and the membrane. The gap may be substantially occupied by air and may not allow the liquid material to flow from the conjugate pad into the membrane. After the desired conjugate time is achieved (e.g., after a timer expires), the gap may be removed by pressing the conjugate pad and the membrane together. After the gap is removed, the liquid material may flow from the conjugate pad into the membrane by capillary action. 
     In some of the present embodiments, the gap may be maintained by a movable section of the lateral flow assay device&#39;s housing. After a desired time is achieved, the gap may be removed by moving the movable section of the housing towards the membrane until the conjugate pad and the membrane come into contact with each other. In some of the present embodiments, a solenoid, an electromagnet, a servo, or a linear actuator may be used to move the movable section of the housing to remove the gap after a specific amount from the start of the test. For example, at the start of the assay test, a timer may be set to provide a desired conjugate time. After the timer is expired, a signal may be generated to cause the solenoid, the electromagnet, the servo, or the linear actuator to push the movable section of the housing to remove the gap. In some of the present embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of the lateral flow assay device. In other embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of a separate non-disposable device that couples with the lateral flow assay during the testing. 
     In some of the present embodiments, the gap may be maintained by one or more small poles (pillar, rods) and/or springs between the conjugate pad and the membrane. In some of the present embodiments, a solenoid, an electromagnet, a servo, or a linear actuator may be used to pull (or push) the pole(s) or the spring(s) to remove the gap after a specific amount from the start of the test. For example, at the start of the assay test, a timer may be set to provide a desired conjugate time. After the timer is expired, a signal may be generated to cause the solenoid, the electromagnet, the servo, or the linear actuator to pull (or push) the pole(s) or the spring(s) to remove the gap. In some of the present embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of the lateral flow assay device. In other embodiments, the solenoid, the electromagnet, the servo, or the linear actuator may be a part of a separate non-disposable device that couples with the lateral flow assay during the testing. 
     Some of the present embodiments may include a gap to prevent the fluid material to flow from the test line towards the control line and the wicking pad. After a desired time is achieved for the immobilized molecules at the test line to bind with the fluid material, the gap may be removed to allow the fluid material to flow from the test line towards the control line and the wicking pad. Some of the present embodiments may include a gap to prevent the fluid material to flow from the control line towards the wicking pad. After a desired time is achieved for the immobilized molecules at the control line to bind with the fluid material, the gap may be removed to allow the fluid material to flow from the control line towards the wicking pad. Some of the present embodiments may include more than of the aforementioned three gaps. 
     In some embodiments, the gap between the conjugate pad and the membrane may be repeatedly opened and closed to control the flow of fluid material from the conjugate pad into the membrane. The number of times the gap is opened and closed, the duration that the gap remains open or closed, and the time between the opening and the closings of the gap may control the amount of contact between the conjugate pad and the membrane. The amount of contact between the conjugate pad and the membrane may in turn be used to control the flow time. A similar technique may be used to repeatedly open and close the gap that control the flow of the fluid material from the test line towards the control line and/or the gap that controls the flow of the fluid material from the control line towards the wicking pad. 
     In some embodiments, the backing card of conjugate pad or the backing card of the membrane pad may be curved to initially (e.g., prior to the start of a test and for a time period after the start of the test) prevent the pads from touching each other. A mechanism such as a solenoid, a small linear actuator, or a small servo motor may be used to repeatedly bring the conjugate pad and the membrane in touch with and then separate them from each other. Repeatedly connecting and disconnecting the conjugate pad and the membrane may be used to control the flow of fluid material from the conjugate pad into the membrane. 
     The connecting and disconnecting of the conjugate pad and the membrane may be done according to an algorithm controlled by a processor of the lateral flow assay device. The processor may use three parameters to generate one or more signals to connect and disconnect the conjugate pad and the membrane pad in order to control the flow time of the fluid from the time the fluid starts at the beginning of the membrane to the time the fluid reaches the wicking pad. The three parameters are the number of times the pads are connected (or disconnected), the duration of each connections, and the duration of each disconnection (or the time between consecutive connection and disconnections). 
     The longer the duration of each connection, the more fluid is transferred from the conjugate pad to the membrane. These three parameters may be calculated by the processor using an algorithm and a set of calibration tables or calibration curves. The algorithm input may be the desired conjugation time and flow time. 
       FIG. 1  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  100 , according to various aspects of the present disclosure. The lateral flow assay (also referred to as lateral flow immunochromatographic assay or lateral flow dipstick immunoassay) device  100  may be a portable device (e.g., a handheld device or benchtop device) that is used to analyze a sample fluid (also referred to as matrix) to determine the presence and/or the amount of one or more analytes (referred to as target analytes). In this specification, the terms lateral flow assay device and lateral flow assay are interchangeably used to refer to a device that performs lateral flow tests. 
     The lateral flow assay device  100  may include a replaceable cartridge that may be intended for single use. For example, the components shown in  FIG. 1  may be part of a disposable cartridge of the lateral flow assay device  100 . As described below, the lateral flow assay device  100  may also include components such as actuators, processors, displays, etc., that may or may not be disposable. The non-disposable components of the lateral flow assay device may be used for performing multiple tests for the same or different subjects (e.g., the same person or different persons). 
     The sample may be human or animal bodily fluid, such as, without limitations, one or more of urine, blood, serum, plasma, saliva, sweat, milk, mucous, semen, vaginal or urethral secretions, etc. The sample may also be a fluid taken from sources other than a human or an animal. For example, the sample may contain plant material, fuel, food, drink, animal feed, drugs, chemical compounds, etc. The sample may naturally be a liquid, may be a liquid diluted with another liquid, such as water, or may have originally been in a solid form (e.g., a tissue sample) and is treated to be in liquid form for the application to the lateral flow assay device  100 . The target analytes may be substances such as, without limitations, proteins, haptens, enzymes, hormones, infectious disease agents, immunoglobulins, polynucleotides, steroids, drugs, nucleic acids, markers for gene mutations, etc. 
     I. Using Removable Physical Barriers in the Flow Path to Control the Flow and Flow Time 
     With reference to  FIG. 1 , the lateral flow assay device  100  may include a sample receiving zone  101 , a labeling zone  102 , a barrier zone  103 , a capture zone  104 , and optionally a wicking zone  105 . The sample receiving zone  101 , the labeling zone  102 , the capture zone  104 , and the wicking zone  105  may be made of materials that make a fluid sample applied to the sample receiving zone  101  flow by capillary action downstream (i.e., from the sample receiving zone  101  towards the wicking zone  105 ) from each zone  101 ,  102 , and  104  into the next adjacent zone  102 ,  104 , and  105 , respectively. 
     The sample receiving zone  101  may include a sample pad (also referred to as sample strip or sample receiving member)  150 . The sample pad  150  may be made of natural and/or synthetic porous, microporous, mesoporous, or macroporous materials capable of receiving a sample fluid and laterally conducting the sample fluid towards the labeling zone  102  by capillary action. The sample pad  150  may be made of a material such as, without limitations, cellulose, nitrocellulose, paper, silica, cotton, glass (e.g., glass fiber), or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.). Depending on the type of the sample (e.g., urine, saliva, blood, etc.), the sample pad  150  may be treated by a buffer (e.g., an organic compound such as tris or tris(hydroxymethyl)aminomethane) to mitigate sample variabilities (pH, protein concentration, viscosity, salt concentration, etc.). During the manufacture of the sample pad  150 , the buffer compound may be coated, impregnated, or otherwise applied or deposited on the sample pad  150  and then dried. 
     With further reference to  FIG. 1 , the labeling zone  102  may include a conjugate pad  110  that is fluidically connected (i.e., capable of receiving fluid, e.g., by capillary action) to the sample pad  150 . In the depicted embodiment, the sample pad  150  is in contact with and partially covers the conjugate pad  110 . In other embodiments, the sample pad  150  may be in more contact or less contact with the conjugate pad  110  in order to provide slower or faster binding reagent and/or conjugate release respectively. A sample fluid that is applied to the sample pad  150  may be laterally transferred from the sample pad  150  to the conjugate pad  110  by capillary action. 
     The conjugate pad  110  may be made of natural and/or synthetic porous, microporous, mesoporous, or macroporous materials capable of receiving the sample fluid from the sample pad  150 . The conjugate pad  110  may be made of material such as, without limitations, glass (e.g., glass fiber), cellulose, nitrocellulose, paper, silica, cotton, or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.). 
     The conjugate pad may contain a binding reagent (also referred to as antibody) that is capable of binding to the target analyte in the sample fluid. The binding reagent may be coupled to a label (also referred to as conjugate, detection conjugate, probe, or detector nanoparticle) which, in its natural state, is readily visible either to the naked eye, or with the aid of an optical filter. Depending on the type of the lateral flow assay, the binding reagent may be an antibody, an antigen, a protein, a nucleic acid, etc., that is capable of binding to the target analyte. The label may be made of small particles (e.g., nanoparticles), such as, without limitations, metallic sols (e.g., colloidal gold or gold sol), dye sols, colored latex particles, carbon, etc. During the manufacture of the conjugate pad  110 , the labeled binding reagent may be coated, impregnated, or otherwise applied or deposited on the conjugate pad  110  and then dried. 
     After the sample fluid flows from the sample pad  150  into the conjugate pad  110 , the sample fluid may solubilize the labeled binding reagent. If the sample fluid contains the target analyte, the target analyte may bind with the labeled binding reagent and form an immunocomplex. The labeled binding reagents that do not bind with the target analyte (e.g., when the sample fluid does not include the target analyte or there is excess labeled binding reagent) flow downstream towards the capture zone  104  by capillary action. As described below, some of the present embodiments may include a barrier zone  103  that may initially block the sample fluid and any other material in the flow path (e.g., unbound labeled binding reagents, wash fluid, etc.) from flowing from the labeling zone  102  into the capture zone  104 . The sample fluid and any other material in the flow path (e.g., unbound labeled binding reagents, wash fluid, etc.) are herein referred to as fluid material. 
     Depending on the type of test performed by the lateral flow assay device, the device may not include separate sample and conjugate pads in some embodiments and may only include the conjugate pad  110 . Although the sample pad  150  is shown to go over the conjugate pad  110 , in some embodiments, the conjugate pad  110  may go over the sample pad  150 . 
     The capture zone  104  may include a membrane  115  and a test line (or test zone)  125  that may be embedded in the membrane. The capture zone  104  may optionally include a control line (or control zone)  130  that may be embedded in the membrane  115 . The membrane  115  may be made of a material such as, without limitations, cellulose, nitrocellulose, paper, silica, cotton, glass (e.g., glass fiber), or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.) that allow the fluid material to flow downstream from the conjugate pad  101  into the membrane  115  and from the membrane  115  towards the wicking zone  105  by capillary action. Although the conjugate pad  110  is shown to go over the membrane  115 , in some embodiments, the membrane  115  may go over the conjugate pad  110 . 
     The test line  125  may be made of a porous material such as, without limitations, cellulose, nitrocellulose, paper, silica, cotton, glass (e.g., glass fiber), or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.). The test line  125 , in a sandwich assay format, may contain an unlabeled binding reagent that is immobilized on the test line  125  and does not flow downstream when porous material of the test line is moistened (e.g., by the fluid material). Depending on a particular test made by the lateral flow assay device  100 , the binding reagent immobilized on the test line may be the same or different than the binding reagent contained on the conjugate pad  110 . 
     In the sandwich assay format, the binding reagent contained on the test line  125  may be an immobilized antibody that is capable of binding to the immunocomplex that is formed from the binding of the analyte with the labelled binding reagent on the conjugate pad  110 . As the immunocomplex moves over the test line  125 , the immunocomplex binds with the immobilized antibody on the test line  125 , resulting in a second immunocomplex that colors the test line  125 . The intensity of the colored test line is correlated with the density of the analyte in the sample fluid. The second immunocomplex includes the analyte that is bound with the labelled binding reagent at one site and is bound with the immobilized binding agent at another site. When the sample fluid does not include the target analyte, no immunocomplex is formed on the conjugate pad  110  and no immunocomplex binds with the immobilized antibody on the test line  125 . As a result, the test line  125  does not change color. 
     In a competitive assay format, the test line  125  may contain the immobilized analyte molecule (or a protein-analyte complex). If the sample liquid does not contain the analyte, the labeled antibody that is solubilized by the sample liquid may flow from the conjugate pad  110  into the test line  125  and may bind to the analyte at the test line  125 , resulting in a colored test line  125  that indicates the lack of the target analyte in the sample liquid. If the target analyte is present in the sample liquid, the analyte may bind to the labeled antibodies on the conjugate pad  110  and may prevent the labeled antibody to bind to the analyte at the test line  125 . As a result, the test line  125  may not change color, indicating the presence of the analyte in the sample fluid. 
     The capture zone  104  may optionally include a control line (or control zone)  130  that may be embedded in the membrane  115 . The control line  130  may be made of a porous material such as, without limitation, cellulose, nitrocellulose, paper, silica, cotton, glass (e.g., glass fiber), or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.). In a sandwich assay format, the control line  130  may contain an immobilized antibody that binds to the free labeled binding reagents resulting in a colored control line  130 , which confirms that the test has operated correctly regardless of whether or not the target analyte has been present in the sample. In a competitive assay format, the control line  130  may contain an immobilized analyte molecule (or a protein-analyte complex) that binds to the free labeled binding reagents resulting in a colored control line  130 , which confirms that the test has operated correctly regardless of whether or not the target analyte has been present in the sample. 
     The fluid material that do not bind to the test line  125  or the control line  130  may continue to flow from the capture zone  104  into the wicking zone  105 . The wicking zone  105  may include a wicking pad  120  to absorb the fluid material that are not taken up by the test line  125  and the control line  130  while maintaining the capillary flow from the membrane  125  into the wicking pad  120 . The wicking pad  120  may be made of a porous material such as, without limitations, cellulose, nitrocellulose, paper, silica, cotton, glass (e.g., glass fiber), or synthetic material (e.g., polyester, polyethylene, polymers, rayon, nylon, etc.). Depending on the type of test performed by the lateral flow assay device, the device may not include a wicking zone  105  or a wicking pad  120 . Although the wicking pad  120  is shown to go over the membrane  115 , in some embodiments, the membrane  115  may go over the wicking pad  120 . 
     In some of the present embodiments, the analyte in the sample fluid may require more time to bind with the labeled binding reagent than the time it takes for the sample fluid to flow by capillary action through the conjugate pad  110  into the membrane  115 . For example, without limitation, the target analyte may inherently require a long time to bind with the labeled binding reagent. The required binding time may depend on the type and concentration of the target analyte and the labeled binding reagent. 
     If the analyte is not provided enough time on the conjugate pad  110  to bind with the labeled binding reagent, there may not be enough immunocomplex in fluid that flows to the test line  125  to bind with the immobilized binding reagent on the test line  125  in a sandwich assay format (or with the immobilized analyte/protein-analyte complex in a competitive assay format) to generate a strong color signal at the test line  125  to indicate the presence or absence of the target analyte in the sample fluid. Furthermore, it may be desirable to precisely control the time allowed for the analyte to bind with the labeled binding reagent regardless of the amount of time required for the analyte to bind with the labeled binding reagent on the conjugate pad. 
     Some of the present embodiments provide a barrier zone  103  between the labeling zone  102  and the capture zone  104 . The barrier zone  103  may include a removable barrier  135 . In the embodiment depicted in  FIG. 1 , the removable barrier is a physical barrier made of solid material (e.g., a thin film of material) that prevents the flow of the fluid material from the labeling zone  102  into the capture zone  104 . The physical barrier  135  may be made of materials that do not react with the sample fluid and any other material in the flow path (e.g., unbound labeled binding reagents, wash fluid, etc.). In other embodiments (e.g., as shown in  FIG. 20  described below) the barrier zone  103  may include a gap that may be substantially occupied by air. 
     In some of the present embodiments, a timer is programmed to allow time for the analyte in the sample fluid to bind with the labeled binding reagent on the conjugate pad  110 . The timer may start at the beginning of the test (e.g., substantially at or around the same time as the sample liquid is applied to the sample pad  150 ). The timer may be set such that enough time is allowed for the sample fluid to flow from the sample pad  150  into the conjugate pad  110  and for the analyte (if any) in the sample fluid to bind with the labelled binding reagent on the conjugate pad  110 . 
     After the timer expires, the physical barrier  135  may be removed from between the labeling zone  102  and the capture zone  104  in order to fluidically connect the conjugate pad  110  in the labeling zone  102  to the membrane  115  in the capture zone  104 . After the conjugate pad  110  and the membrane  115  come to contact to each other, the fluid material may flow from the labeling zone  102  into the capture zone  104  by capillary action. 
     The lateral flow assay device  100  may include a backing card  140  that is used to assemble different portions of the sample receiving zone  101 , the labeling zone  102 , the capture zone  104 , and the wicking zone  105 . The backing card, in some embodiments, may be a continuous piece that may go under the pads  150 ,  110 ,  115 , and  120 . In other embodiments, each pad may have a separate backing card. For example, during the manufacturing of the device, a roll or sheet of backing material may be used such that the width of the roll or the sheet is the same as (or is cut to be the same as) the length of the lateral flow assay cartridge (i.e., in the pictured orientation, from the left end of the sample pad  150  to the right end of the wicking pad  120 ). The membrane pad  115 , the conjugate pad  110 , the sample pad,  150 , and the wicking pad  120  are then placed on the backing card with the proper overlaps (e.g., as shown in  FIG. 1 ). The pads may, for example, be connected to the backing card with a two sided tape or a glue. The pads and the attached backing card may then be cut into separate strips and each strip may be used to make a different lateral flow assay device. 
     Alternatively, each pad may be separately connected to a corresponding backing card. The pads with the corresponding backing cards may then be assembled over each other with the proper overlaps to make a lateral flow assay device. The lateral flow assay device  100  may include a housing. In  FIG. 1 , only a portion of the housing that includes the cartridge bed  170  is shown for simplicity. 
     In some of the present embodiments, the lateral flow assay may include a housing that may apply pressure to the conjugate pad  110 , the membrane pad  115 , or both. The pressure may facilitate the conjugate pad  110  and the membrane  115  touching each other after the barrier  135  is removed.  FIG. 2  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  100  showing a cross section of the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure. With reference to  FIG. 2 , the perspective shows a cross sectional view of the housing  205  across the surfaces  206 . 
     The housing  205  may include a sample port  210  for applying the sample liquid to the sample pad  150 . The housing  205  may also include an opening  215  for viewing the test line  125 . The embodiments that include a control line  130 , may also include an opening  220  for viewing the control line  130 . Some embodiments may include one opening for viewing both the test line  125  and the control line  130 . The housing  205  may include a cartridge bed  170  for holding the lateral flow assay device&#39;s cartridge. 
     In some of the present embodiments, the housing applies pressure to the conjugate pad  110  and/or the membrane  115  such that when the barrier  135  is removed, the conjugate pad  110  and the membrane  115  come to contact with each other to allow the fluid material in the flow path to flow from the conjugate pad  110  into the membrane  115  by capillary act. 
     For example, portions  225 - 226  of the housing  205  may touch the conjugate pad  110  and apply a force (as shown by the arrows  250 ) to push the conjugate pad  110  towards the barrier  135  and the membrane  115 . In some embodiments, the portions  225 - 226  of the housing  105  may touch a portion of the conjugate pad  110  across a line that is perpendicular to the flow path (the flow path runs from the left to right across the lateral flow assay device  100  in  FIG. 2 ). In other embodiments, the portions  225 - 226  of the housing  205  may be in the form of one or more columns that touch the conjugate pad  110  at one or more places. In addition to, or in lieu of, pushing the conjugate pad  110  towards the barrier  135  and the membrane  115 , the housing  205  may apply a force (as shown by the arrows  255 ) to push the cartridge bed  170 , backing card  140 , and the membrane  115  towards the barrier  135  and the conjugate pad  110 . 
       FIG. 3  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  100  showing the removal of the barrier  135 , according to various aspects of the present disclosure. The figure as shown, includes two operational steps  301  and  302 . 
     With reference to  FIG. 3 , step  301  shows an initial state where the barrier  135  is between the conjugate pad  110  and the membrane  115 . The barrier may be made of a material (e.g., plastic, latex, metal, etc.) which blocks the fluid material from flowing from conjugate pad  110  into the membrane  115 . The barrier&#39;s material is selected from materials that do not react with the fluid material in the flow path. As shown in step  301 , the barrier  135  is flexible and follows (as shown by the dashed lines  335 ) the contours of the membrane  115  and the conjugate pad  110 . 
     In some of the present embodiments, the lateral flow assay device  100  at the start of a test may include the barrier  135  between the conjugate pad  110  and the membrane  115 . For example, lateral flow assay device  100  may be manufactured in the configuration shown in step  301  of  FIG. 3 . A test may start by applying a sample fluid to the conjugate pad  110  (e.g., through the sample port  210  of  FIG. 2 ). In some of the present embodiments, a timer is programmed to allow time for the analyte (if any) in the sample fluid to bind with the labeled binding reagent on the conjugate pad  110 . 
     In step  302  of  FIG. 3 , the barrier  135  is removed (as shown by the arrow  360 ) from between the conjugate pad  110  and the membrane  115 . For example, the barrier  135  may be removed after the expiration of the timer. The force that is applied by the housing  205  of  FIG. 2  to the conjugate pad  110  (as shown by the arrows  250 ) and/or by the force that is applied to the cartridge bed  170 , the backing card  140 , and the membrane  115  (as shown by the arrows  255 ) may make the conjugate pad  110  and the membrane  115  to come in contact with each other and allow the fluid material to flow from the conjugate pad  110  into the membrane  115  by capillary act. Since the barrier is made of a flexible and relatively thin film of material, the barrier may take a substantially uniform shape (as shown in step  302 ) after the barrier  135  is pulled out and is no longer under pressure from the conjugate pad  110  and/or the membrane  115 . 
     In some of the present embodiments, one or more pieces of magnet may be attached to the barrier  135  to facilitate pulling the barrier  135  out from between the conjugate pad  110  and the membrane  115 .  FIG. 4  is an upper front perspective of one example embodiment of a physical barrier with a piece of magnet attached to it, according to various aspects of the present disclosure. As shown in  FIG. 4 , a piece of magnet (e.g., in the shape of a thin strip of magnetic material, in an arbitrary shape, etc.)  405  is attached to one side  410  of the physical barrier  135 . The piece of magnet  405  may facilitate pulling the barrier  135  by another magnet attached to a moving shaft. In some of the present embodiments, more than one piece of magnet may be attached to the side  140  of the physical barrier  135 . 
       FIG. 5  is a functional block diagram illustrating one example embodiment of a linear actuator  525  that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure. The linear actuator  525  may include an electric motor  530 , a rotating shaft  580 , a rotational to linear movement converter  535 , and a linear moving shaft  540 . The electric motor  530 , in some embodiments, may be a miniaturized motor (e.g., a micro motor). The electric motor  530  may include a rotor  570  that may rotate and cause the rotating shaft  580  to rotate. 
     The rotational movement of the rotating shaft  580  may be converted to linear movement of the linear moving shaft  540  by the rotational to linear movement converter  535 . The rotational to linear movement converter  535  may be a set of one or more screws, a wheel and axle, and/or a set of one or more cams that receive a rotational movement from the rotating shaft  580  and move the linear moving shaft  540  in a straight line. 
     The linear moving shaft  540  may move in and out in a straight line towards or away from the rotating shaft  580 . Some of the present embodiments may include one or more magnets  545  (only one magnet is shown) at the end of the linear moving shaft  540 . In some of the present embodiments, a processor (or controller)  505  may be used to set a timer to determine the time to pull out the barrier  135 . Although the terms processor or controller are used in several examples in this specification, it should be understood that these terms apply to different types processing units, processors, central processing units (CPUs), microprocessors, and/or microcontrollers. The processor (or controller)  505  may include a single-core processor or a multi-core processor in different embodiments. 
     In some embodiments, the processor  505  may be associated with, and communicatively coupled to, a user interface (UI)  550  that may include a keyboard and/or a display. The display, in some embodiments, may be a touchscreen. In addition to, or in lieu of the UI  550 , the processor  505 , in some embodiments, may communicate with one or more client devices  515  to send and/or receive signals. 
       FIG. 5  as shown, includes two operational steps  501  and  502 . Step  501  shows that at the beginning of a test, the electric motor  530  may be configured to extend the linear moving shaft  545  away from the rotating shaft  580 , and the linear actuator  525  may be placed adjacent to the cartridge  575  of the lateral flow assay device  100  such that the magnet(s)  545  on the shaft  540  may contact the magnet(s)  405  ( FIG. 4 ) on the barrier  135 . The cartridge  575  may include the components shown in  FIGS. 1 and 3 . In  FIG. 5 , the top view of the lateral flow assay device  100  is shown and the components of the lateral flow assay device  100 , other than the barrier  135 , are not shown for simplicity. 
     In some of the present embodiments, the disposable cartridge  575  of the lateral flow assay device  100  may include a near field communication (NFC) chip (or NFC tag)  590 . The NFC chip  590  may identify the test and other parameters and information related to the test including the conjugation time on the conjugate pad. The lateral flow assay device  100  may also include an NFC reader  595 . Once the cartridge  575  is placed in the lateral flow assay device&#39;s  100  housing (e.g., on the cartridge bed  170  of  FIGS. 1-3 ), the NFC reader  595  (which may be located, for example, and without limitations, under the cartridge bed  170  close to where the NFC chip is located) may automatically detect the presence of the NFC tag. 
     The NFC reader  595  may read the information regarding the test to be performed by the cartridge. The NFC reader  595  may be communicatively coupled with the processor  505 . The processor  505  may receive the information from the NFC reader and, for example, and without limitation, may start a timer to control the conjugate times, may send a signal to activate the electric motor to remove the barrier  135 , may display some of the information on its display of the UI  550 , and/or may send some of the information and parameters to one or more external devices such as the client device  515 . 
     In some embodiments, all components of the lateral flow assay device, including the processor  505 , the UI  550 , etc., may be used for one test and may be disposable. In these embodiments, in addition to, or in lieu of the NFC, the parameters and information regarding the test may be pre-programmed into the processor. In other embodiments, the processor/controller  505 , the UI  550 , the linear actuator  525 , and/or the NFC reader may be reusable for performing multiple tests for the same or different subjects (e.g., the same person or different persons). 
     In some embodiments, in addition to, or in lieu of, using the information from the NFC tag  590 , the processor  505  may receive a value for setting the timer through a wireless link  570  from one or more client devices  515  (only one client device is shown for simplicity). The client device  515  may be, without limitations, a cellular telephone (e.g., a smartphone), a computing device (e.g., a tablet computer, a laptop computer, a desktop computer), a personal digital assistant (PDA) device, an electronic device capable of communicating the timer value to the processor  505 , etc. 
     In some of the present embodiments, the processor  505  and the client device  515  may each include one or more antennas  510  and may establish the wireless link  570  through the antennas  510 . Alternatively, the client device  515  and the processor  505  may be connected by a wired connection (e.g., without limitation, using a cable, using a connection such as USB, thunderbolt, lightning, etc.). The client device  515  may execute an application program that is used to interact with the processor  505  and/or with the lateral flow assay device  100 . For example, the client device  515  may receive a value (e.g., from a user entering the value through a user interface of the application program) for setting a timer value in seconds, in milliseconds, in microseconds, or with any other time units. The client device  515  may then send the timer value to the processor  505  through the wired or wireless connection. 
     In some embodiments, the processor  505  may start the timer after the processor  505  receives a signal indicating the start of a test. In some of the present embodiments, the signal may be received by the processor  505  from the client device  515 . For example, the processor  505  may start the timer as soon as (or a period of time after) the processor  505  receives the value of the timer from the client device  515 . In some embodiments, the signal may be received after a physical switch (e.g., a push button or a toggle switch on the UI  550 ) that is communicatively coupled to the processor  505  is activated to generate the signal. 
     After the time required for the analyte in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the electric motor  530  may receive a signal to pull the linear moving shaft  545  back towards the rotating shaft  580  and away from the cartridge  575  of the lateral flow assay device  100 . After the timer expires, the processor  505  may send one or more signals to the linear actuator  525  to move the linear moving shaft  540  to pull the barrier  135  from between the conjugate pad  110  ( FIG. 3 ) and the membrane  115  ( FIG. 3 ) of the lateral flow assay device  100 . 
     In step  502 , as the linear moving shaft  540  is pulled away from the lateral flow assay device  100  (as shown by the arrow  541 , the magnet(s)  545  on the linear moving shaft  540  may pull the magnet(s)  405  (which is/are firmly attached to the barrier  135 ), causing the barrier  135  to pull out from between the conjugate pad  110  ( FIG. 3 ) and the membrane  115 . The magnets  545  and  405  may have enough magnetic force to allow them to connect to each other (e.g., by magnetic force) and to continue connecting to each other while the barrier  135  is being pulled out from between the conjugate pad  103  and the membrane  115 . 
     In some of the present embodiments, the magnet(s)  545  on the shaft  540  is made to contact the magnet(s)  405  on the barrier at the beginning of a test (when the barrier is located between the conjugate pad  110  and the membrane  115  as shown in step  301  of  FIG. 3 ). The one or more signals may cause the electric motor  530  to generate a predetermined amount of rotational movement to the rotating shaft  580 , which is in turn is converted by the rotational to linear movement converter  535  into a predetermined amount of linear movement on the linear moving shaft  540 . 
     For example, the linear moving shaft  540  may move in a linear direction away from the lateral flow assay device  100 , causing the magnet(s)  545  attached to the magnet  405 ( s ) on the barrier  135  to pull the barrier  135  from between the conjugate pad  110  ( FIG. 3 ) and the membrane  115  ( FIG. 3 ). In some embodiments, the linear moving shaft  540  may move (in the direction of the arrow  541 ) a distance that is the same as or slightly larger than the width  415  ( FIG. 4 ) of the barrier  135  to completely pull the barrier  135  out of the lateral flow assay device  100 . 
     Some of the present embodiments may use a solenoid instead of a linear actuator to pull the barrier  135 .  FIG. 6  is a functional block diagram illustrating one example embodiment of a solenoid  605  that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure. 
     A solenoid may function as a transducer that converts energy into linear motion. The solenoid  605  may include an electromagnetically inductive coil  660  that is wrapped around a movable metallic core (or armature)  610 . When an electric current passes through the wire  650 , a magnetic field is generated by the coil  660  that causes the moveable core  610  to move in a linear line. By changing the direction of the current, the magnetic field is reversed that causes the moveable core  610  to move in the opposite direction. One or more magnets  615  may be attached to one end of the moveable core  610 . 
     The figure as shown, includes two operational steps  601  and  602 . As shown in step  601 , at the beginning of a test, the solenoid  605  may be configured (e.g., by changing the direction of electric current in the wire  650 ) to extend the movable core  610  away from the solenoid  605 , and the solenoid  605  may be placed adjacent to the lateral flow assay device  100  such that the magnet(s)  615  on the movable core  610  contacts the magnet(s)  405  ( FIG. 4 ) on the barrier  135 . In  FIG. 6 , the top view of the lateral flow assay device  100  is shown and the components of the lateral flow assay device  100 , other than the barrier  135 , are not shown for simplicity. 
     The processor  505 , the NFC tag  590 , the NFC reader  595 , and the client device  515  of  FIG. 6  may be similar to the corresponding components of  FIG. 5 . With reference to  FIG. 6 , the processor  505  may receive a value for setting the timer from the NFC tag  590 /NFC reader  595  or from the client device  515 . In some embodiments, the processor  505  may start the timer after the processor  505  receives a signal indicating the start of a test. In some of the present embodiments, the signal may be received by the processor  505  from the client device  515 . For example, the processor  505  may start the timer as soon as (or a period of time after) the processor  505  receives the value of the timer from the client device  515 . In some embodiments, the signal may be received after a physical switch (e.g., a push button or a toggle switch on the UI  550 ) that is communicatively coupled to the processor  505  is activated to generate the signal. 
     In some embodiments, all components of the lateral flow assay device, including the processor  505 , the UI  550 , etc., may be used for one test and may be disposable. In these embodiments, in addition to, or in lieu of the NFC, the parameters and information regarding the test may be pre-programmed into the processor. In other embodiments, the processor/controller  505 , the UI  550 , the solenoid  605 , the power source  640 , the controller circuit  630 , and/or the NFC reader may be reusable for performing multiple tests for the same or different subjects (e.g., the same person or different persons). 
     In step  602 , after the timer expires, the processor  505  may send one or more signals to the controller circuit  630  to change the direction of current in the wire  650  (e.g., by changing the polarity of the voltage that is applied to the wire  650  by the power source  640 ). Changing the direction of current in the wire  650  may change the magnetic field generated by the coil  660  that causes the moveable core  610  to move towards the solenoid  605  and away from the lateral flow assay device  100 , causing the magnet(s)  615  that is attracting the magnet(s)  405  ( FIG. 4 ) on the barrier  135  to pull the barrier  135  from between the conjugate pad  110  ( FIG. 3 ) and the membrane  115  ( FIG. 3 ). The magnets  615  and  405  may have the polarities (e.g., opposite polarities to attract each other) and enough magnetic force to allow them to connect to each other (e.g., by magnetic force) and to continue connecting to each other while the barrier  135  is being pulled out from between the conjugate pad  103  and the membrane  115 . In some embodiments, the movable core  610  may move (in the direction of the arrow  690 ) a distance that is the same as or slightly larger than the width  415  ( FIG. 4 ) of the barrier  135  to completely pull the barrier  135  out of the lateral flow assay device  100 . 
     Some of the present embodiments may use an electromagnet instead of a linear actuator or a solenoid to pull the barrier  135 .  FIG. 7  is a functional block diagram illustrating one example embodiment of an electromagnet  770  that may be used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure. In  FIG. 7 , the top view of the lateral flow assay device  100  is shown and the details of the lateral flow assay device  100 , other than the barrier  135 , are not shown for simplicity. 
     In an electromagnet, a magnetic field is generated by an electric current. The magnetic field disappears when the electric current is turned off. The electromagnet  770  may include an electromagnetically inductive coil  705  that is wrapped around a metallic core  710 . When the electric current is turned off, the coil  705  no longer generates a magnetic field. 
     The figure as shown, includes two operational steps  701  and  702 . As shown in step  701 , at the beginning of a test, the switch  750  may be off such that no current is passed through the power source  740 , the wire  750 , and the core  710 . The coil  705  may not generate a magnetic field and the metallic core  710  may not act as a magnet. In step  701 , the electromagnet  770  may be placed adjacent to the cartridge  575  of the lateral flow assay device  100  such that the magnet(s)  405  ( FIG. 4 ) on the barrier  135  is/are at a predetermined distance “d1” from the core  710 . The distance “d1” may be just enough to allow the removable barrier  135  to be completely pulled out of lateral flow assay device  100  when the electromagnet  770  is turned on. 
     The processor  505 , the NFC tag  590 , the NFC reader  595 , and the client device  515  of  FIG. 7  are similar to the corresponding components of  FIG. 5 . With reference to  FIG. 7 , the processor  505  may receive the values of the test parameters from the NFC tag  590 /NFC reader  595  or from the client device  515 . In some embodiments, the processor  505  may start the timer after the processor  505  receives a signal indicating the start of a test. In some of the present embodiments, the signal may be received by the processor  505  from the client device  515 . For example, the processor  505  may start the timer as soon as (or a period of time after) the processor  505  receives the value of the timer from the client device  515 . In some embodiments, the signal may be received after a physical switch (e.g., a push button or a toggle switch on the UI  550 ) that is communicatively coupled to the processor  505  is activated to generate the signal. 
     In some embodiments, all components of the lateral flow assay device, including the processor  505 , the UI  550 , etc., may be used for one test and may be disposable. In these embodiments, in addition to, or in lieu of the NFC, the parameters and information regarding the test may be pre-programmed into the processor. In other embodiments, the processor/controller  505 , the UI  550 , the coil  705 , the power source  740 , the controller circuit  730 , and/or the NFC reader may be reusable for performing multiple tests for the same or different subjects (e.g., the same person or different persons). 
     In step  702 , after the timer expires, the processor  505  may send one or more signals to the controller circuit  730  to close the switch  750  to have a current flow from the power source  740  through the wire  750  and the coil  705 . The current in the coil  705  may cause the coil  705  to generate a magnetic field and make the core  710  to become a magnet. The core  710  acting as a magnet may then magnetically attract the magnets(s)  405  ( FIG. 4 ) on the barrier  135  to pull the barrier  135  from between the conjugate pad  110  ( FIG. 3 ) and the membrane  115  ( FIG. 3 ). The magnet generated by the core  710  may have the polarity (e.g., the opposite polarity of the magnet(s)  405 ) and enough magnetic force to pull the magnet(s)  405  on the barrier  135  and the barrier  135  from between the conjugate pad  103  ( FIG. 3 ) and the membrane  115  ( FIG. 3 ). 
     As shown in steps  701  and  702  of  FIG. 7 , the distance “d1” between the core  710  and the cartridge  575  of the lateral flow assay device  100  may not change as the barrier  135  is being pulled out. The distance “d1” in some embodiments is adjusted at the beginning of a test such that when the electromagnet is turn on (e.g., as described with reference to step  702 ), the barrier  135  is completely pulled out of the lateral flow assay device  100 . For example, in some embodiments, the distance “d1” may be the same as, or slightly larger, than the width  415  ( FIG. 4 ) of the barrier  135 . 
     Some of the present embodiments may use a hook instead of a magnet to pull the barrier  135  from between the conjugate pad  110  and the membrane  115 .  FIG. 8  is an upper front perspective of one example embodiment of a physical barrier that includes a hole, according to various aspects of the present disclosure. The physical barrier  835  may be made of similar materials as the physical barrier  135  ( FIGS. 1-4 ). 
     With reference to  FIG. 8 , the physical barrier  835  may have a width  815  that is wider than the width of the conjugate pad  110  and the membrane  115 . The barrier  835  may be initially (e.g., at the manufacture time of the lateral flow assay device and/or at the beginning of a test) placed between the conjugate pad  110  and the membrane  115  in such a way that the barrier  835  prevents the flow of the fluid material from the conjugate pad  110  into the membrane  115  and a portion  810  of the barrier comes out of the lateral flow assay device housing  205  of  FIG. 2 . 
     As shown in  FIG. 8 , the portion  810  of the physical barrier  835  that comes out of the lateral flow assay device housing may include one or more holes  805  (only one hole is shown in  FIG. 8 ). The hole  805  may be used to pass a hook through the hole  805  to pull the barrier  835  from between the conjugate pad  110  and the membrane  115  ( FIG. 3 ). 
       FIG. 9  is a functional block diagram illustrating one example embodiment of the linear moving shaft of  FIG. 5  with a hook that is used for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure. The linear moving shaft  910  in  FIG. 9  is similar to the linear moving shaft  540  of  FIG. 5  except that the linear moving shaft  910  has a hook  905 , instead of a magnet, attached to one end of the linear moving shaft  910 . 
     The linear moving shaft  910  may be part of a linear actuator similar to the linear actuator of  FIG. 5 . The hook  905  may fit into the hole  805  of  FIG. 8 . In the embodiments that the barrier  835  includes more than one hole  805 , the linear moving shaft may include the same number of hooks  905  as the holes  805 . When the linear moving shaft  910  is moved away from the lateral flow assay device (e.g., after the timer described above is expired), the hook pulls out the physical barrier  837  from between the conjugate pad  110  and the membrane  115 . When the physical barrier  835  has more than one hole  805 , the hook  905  may have more than one head to fit in the holes  805 . 
     A hook similar to the hook  905  may be placed on the movable core  610  of  FIG. 6  (instead of a magnet  615 ) in order to pull out the physical barrier  835  from between the conjugate pad  110  and the membrane  115 . In some of the present embodiments, a string may pass through the hole(s)  805  of  FIG. 5  and the string may be used to pull the physical barrier  835  from between the conjugate pad  110  and the membrane  115  (e.g., by using a linear actuator or a solenoid as described above). 
     In some of the present embodiments, the physical barrier may be manually pulled out from between the conjugate pad  110  and the membrane  115 . For example, the string described above may be used to manually pull the barrier out (e.g., after the timer described above expires and the processor  505  of  FIGS. 5-6  makes a visual and/or audible signal to indicate that the timer has expired).  FIG. 10  is an upper front perspective of one example embodiment of a physical barrier that includes a groove for pulling out the physical barrier of a lateral flow assay device, according to various aspects of the present disclosure. The physical barrier  1035  may be made of similar materials as the physical barrier  135  ( FIGS. 1-4 ). 
     With reference to  FIG. 10 , the physical barrier  1035  may a have a width  1015  that is wider than the width of the conjugate pad  110  ( FIG. 1 ) and the membrane  115  ( FIG. 1 ). The barrier  1035  may be initially (e.g., at the manufacture time of the lateral flow assay device and/or at the beginning of a test) placed between the conjugate pad  110  and the membrane  115  in such a way that the barrier  1035  prevents the flow of the sample fluid from the conjugate pad  110  into the membrane  115  and a portion  1010  of the barrier comes out of the lateral flow assay device housing  205  of  FIG. 2 . 
     The physical barrier  1035  may a have a groove  1005  in the portion  1010  of the physical barrier  1035  that comes out of the lateral flow assay device&#39;s housing  205 . The groove  1005  may be used to manually pull out the barrier  1035  from between the conjugate pad  110  and the membrane  115  (e.g., after the timer described above expires and the processor  505  of  FIG. 5 or 6  makes a visual and/or audible signal to indicate that the timer has expired). 
       FIG. 11  is a flowchart illustrating an example process  1100  for pulling out a barrier that separates the labeling and capture zones of a lateral flow assay device, according to various aspects of the present disclosure. In some of the present embodiments, the process  1100  may be performed by a processor  505  ( FIGS. 5-7 ). 
     With reference to  FIG. 11 , the process  1100  may send (at block  1105 ) one or more signals to a device to adjust the position of the device with respect to the lateral flow assay device  100  ( FIGS. 1-3 and 5-7 ) and/or to set up the device to pull the barrier  135  out of the lateral flow assay device. As a first example, the processor  505  of  FIG. 5  may send one or more signals to the electric motor  530  to rotate the rotating shaft  580  to cause the linear moving shaft  540  to move such that the magnet(s)  545  on the linear moving shaft  540  come(s) in contact with the magnet(s)  405  ( FIG. 4 ) on the barrier  135 . Alternatively, the one or more signals may cause one or more hooks  908  ( FIG. 9 ) on the rotating shaft  580  to engage with one or more holes  805  ( FIG. 8 ) on the barrier  135 . 
     As a second example, the processor  505  of  FIG. 6  may send one or more signals to the controller circuit  630  to adjust the electric current in the wire  650  and the coil  660  such that the magnet(s)  615  on the movable core  610  come(s) in contact with the magnet(s)  405  ( FIG. 4 ) on the barrier  135 . Alternatively, the one or more signals may cause one or more hooks  908  ( FIG. 9 ) on the movable core  610  to engage with one or more holes  805  ( FIG. 8 ) on the barrier  135 . As a third example, the processor  505  of  FIG. 7  may send one or more signals to the controller circuit  730  to turn off the switch  750  in order for the core  710  not to act as a magnet while the core  710  is kept at a distance “d1” from the barrier  135  as described above by reference to  FIG. 7 . 
     With further reference to  FIG. 11 , the process  1100  may receive (at block  1110 ) a signal that may include a value to set a timer for removing the barrier. The signal, in some embodiments, may include a value that indicates the amount of time in a predetermined unit of time (e.g., hours, minutes, seconds, milliseconds, microseconds, etc.). The signal, in some embodiments, may include a value and a unit of time (e.g., 2 seconds, 45 milliseconds, etc.). 
     In some of the present embodiments, the process  1100  may receive, at the processor  505  ( FIGS. 5-7 ), a signal that includes the test parameters values (e.g., and without limitations, the timer value) from the NFC tag  590  and the NFC reader  595 . In some of the present embodiments, the process  1100  may receive, at the processor  505  ( FIGS. 5-7 ), a signal that includes test parameters values from the client device  515 . In some embodiments, the processor  505  may be associated with, and communicatively coupled to, a user interface including a keyboard and/or a display (e.g., a touchscreen). In these embodiments, the process  1100  may receive, at the processor  505 , the signal that includes the test parameter values from the keyboard and/or the touchscreen associated with the processor. 
     With continued reference to  FIG. 11 , the process  1100  may then set (at block  1115 ) a timer to expire after a time period that is identified by the received timer value. For example, the processor  505  may set an internal timer to expire after a time period determined by the received timer value. The process  1100  may then determine (at block  1120 ) whether to start the timer. 
     In some of the present embodiments, the process  1100  may receive a signal to start the timer, which is different that the signal that includes the timer value. For example, the client device  515  ( FIGS. 5-7 ) may receive a signal through the application executing on the client device  515  indicating the start of the test. The process  1100  may then receive a signal, at the processor  505 , from the client device  515  indicating the start of the test. Alternatively, the process  1100  may receive the signal after a physical switch (e.g., a push button or a toggle switch) that is communicatively coupled to the processor  505  is activated to generate the signal. In some of the present embodiments, the process  1100  may start the timer as soon as the timer value is set (at block  1115 ). These embodiments may bypass block  1120   
     When the process  1100  determines (at block  1120 ) that the timer should not be started, the process  1100  may proceed back to block  1120 . Otherwise, the process  1100  may start (at block  1125 ) the timer. The process  1100  may then determine (at block  1130 ) whether the timer has expired. When the process  1100  determines (at block  1130 ) that the timer has not expired, the process  1100  may proceed back to block  1130  to wait for the timer to expire. 
     Otherwise, the process  1100  may send (at  1135 ) one or more signals to move a shaft to pull the barrier from between the labeling and capture zones of the lateral flow assay device. The process  1100  may then end. As a first example, with reference to  FIG. 5 , the processor  505  may send one or more signals to the electric motor  530  to rotate and cause the rotational to linear movement converter  535  to move the shaft  540  a predetermined distance in order to pull the barrier  135  ( FIGS. 1-4 ) from between the conjugate pad  110  and the membrane  115 . 
     In some embodiments, the magnet(s)  545  on the linear moving shaft  540  is/are made to contact the magnet(s)  405  (or the hook(s)  905  of  FIG. 9  is/are made to engage the hole(s)  805  of  FIG. 8 ) on the barrier at the beginning of a test (when the barrier is located between the conjugate pad  110  and the membrane  115 ). The one or more signals (sent at block  1135 ) may be sent from the processor  505  to the electric motor  530 , causing the electric motor  530  to rotate the rotating shaft  580  by a predetermined amount, the rotational to linear movement converter  535  to cause the linear moving shaft  540  to move in a linear direction (e.g., away from the lateral flow assay device), causing the magnet(s)  545  that is/are attached to the magnet(s)  405  (or the hook(s)  905  that is/are engaged in the hole(s)  805 ) on the barrier  135  to pull the barrier  1135  out from between the conjugate pad  110  and the membrane  115 . 
     As a second example, with reference to  FIG. 6 , the processor  505  may send one or more signals to the controller circuit  630  to change the direction of the electrical current in the wire  650  and cause the movable core  610  to move a predetermined distance causing the magnet(s)  615  that is/are attached to the magnet(s)  405  (or the hook(s)  905  that is/are engaged in the hole(s)  805 ) on the barrier  135  to pull the barrier  1135  out from between the conjugate pad  110  and the membrane  115 . As a third example, the processor  505  of  FIG. 7  may send one or more signals to the controller circuit  730  to turn one the switch  750  in order for the core  710  to act as a magnet and pull the magnet  405  ( FIG. 4 ) that is attached to the barrier  135  out of the lateral flow assay device  100 . 
     With reference to  FIGS. 1 and 3 , the removable barrier  135  may be used to prevent the flow of the fluid material from the conjugate pad  110  into the membrane  115  until a timer expires and the barrier  135  is removed. However, depending on the type of material used for the conjugate pad  110 , the membrane pad  115 , and the backing card  140 , and/or the way the pads  110  and  115  are placed on the cartridge bed  170 , even when the barrier  135  is in place, some of the fluid material may leak from under the conjugate pad  110  (e.g., through the backing card  140  and/or the cartridge bed  170 ) into the membrane  115 . 
     To prevent such a leak, some embodiments may include a permanent gap in the cartridge bed and/or in the backing card  140  in order to prevent the fluid material to leak from under the conjugate pad  110  into the membrane  115  while the barrier  135  is in place. Once the barrier is removed, the fluid may flow freely from the conjugate pad  110  into the membrane  115 . 
       FIG. 12  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device that includes a permanent gap in the backing card and/or the cartridge bed to prevent the leaking of the fluid material from under the conjugate pad into the membrane while the barrier is in place, according to various aspects of the present disclosure. 
     With reference to  FIG. 12 , the cartridge bed  171  and  172  may have a permanent gap  1205  such that there is no cartridge bed under a portion of the conjugate pad  110  and the membrane  115  where the barrier  135  is located between the conjugate pad  110  and the membrane  115 . In some embodiments, the cartridge bed may be made of two separate sections  171  and  172 , one section on each side of the cartridge bed gap  1205 . The two sections  171  and  172  of the cartridge bed may be secured on the housing (as shown below with reference to  FIGS. 14 and 15 ) of the lateral flow assay device  100 . 
     In addition, there may be a gap  1210  in the backing card  140 . In the embodiments that the conjugate pad  110  and the membrane  115  have individual backing cards, each backing card is made such that the backing card of the conjugate pad and the backing card of the membrane do not touch each other. 
     In the depicted embodiment, a portion of the backing card that is under the membrane has crossed over the cartridge bed gap  1205 . However, there is still a gap  1210  between the backing card that is under the membrane  115  and the backing card that is under the conjugate pad  110 . In other embodiments, the backing card that is under the membrane  115  may not cross over the cartridge bed gap  1205 . In yet other embodiments, the portion of the backing card that is under the conjugate pad  110  may cross over the cartridge bed gap  1205  while maintaining the gap  1210  with the portion of the backing card that is under the membrane  115 . 
       FIG. 13  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device with a permanent gap in the backing card and/or the cartridge bed, showing the removal of the barrier, according to various aspects of the present disclosure. The figure as shown, includes two operational steps  1301  and  1302 . 
     With reference to  FIG. 13 , step  1301  shows an initial state where the barrier  135  is between the conjugate pad  110  and the membrane  115 . The barrier may be similar to the barrier  135  of  FIG. 3 . The cartridge bed gap  1205  and/or the backing card gap  1210  prevent the fluid material to leak from underneath the conjugate pad  100  into the membrane  115 . As shown by the arrows  1305 , as long as the barrier  135  is between the conjugate pad  110  and the membrane  115 , fluid material cannot flow from the conjugate pad  110  into the membrane  115 . The cartridge bed gap  1205  and/or the backing card gap  1210  provide the technical advantage of preventing the fluid material from leaking from under the conjugate pad  110  into the membrane  115  while the barrier  135  is between the conjugate pad  110  and the membrane  115 . 
     In step  1302  of  FIG. 13 , the barrier  135  is removed (as shown by the arrow  360 ) from between the conjugate pad  110  and the membrane  115  (e.g., when a timer expires and the barrier is removed as described above with reference to  FIGS. 5-7 ). As shown by the arrows  1310 , once the barrier  135  is removed, the fluid material may flow from the conjugate pad  110  into the membrane  115 . 
       FIG. 14  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  100  showing a cartridge inside the device&#39;s housing, according to various aspects of the present disclosure.  FIG. 15  is a front elevation view of the lateral flow assay device of  FIG. 14 , according to various aspects of the present disclosure. 
     With reference to  FIGS. 14 and 15 , the housing  1405  may include a sample port  1460  for applying the sample liquid to the lateral flow assay device  100 . In the example of  FIG. 14 , the lateral flow assay device  100  does not include a separate sample pad. As shown, the lateral flow assay device  100  may include a conjugate pad  110 , a removable barrier  135 , a membrane  115 , a test line  125 , a control line  130 , and a wicking pad  120 . The conjugate pad  110  may act as both the sample pad to receive a sample fluid and as the conjugate pad to contain a binding reagent that is capable of binding to the target analyte in the sample fluid. 
     The lateral flow assay device  100  may include an optional plasma filter  1420 . When the sample fluid includes blood, the plasma filter  1420  may be used to filter and pass the plasma while stopping the flow of red blood cells onto the conjugate pad  110 . 
     The housing  205  may also include an opening  215  for viewing the test line  125 . The embodiments that include a control line  130 , may also include an opening  220  for viewing the control line  130 . Some embodiments may include one opening for viewing both the test line  125  and the control line  130 . The housing  205  may include a cartridge bed  171  and  172  for holding the lateral flow assay device&#39;s cartridge. 
     With further reference to  FIGS. 14 and 15 , the cartridge bed  171  and  172  may include a permanent cartridge bed gap  1205 . As shown, the barrier  135  and a portion of the conjugate pad  110  and the membrane  115  are located over the cartridge bed gap  1205  to prevent the fluid material to leak from under the conjugate pad into the membrane  115 . The two sections  171  and  172  of the cartridge bed on either side of the cartridge bed gap  1205  may be fixed to the housing  1405 , for example, and without limitations, by one or more support columns/support structures  1430 . The housing may include one or more other support columns/support structures  1435  to hold the cartridge of the lateral flow assay device (that includes the components shown in  FIGS. 14 and 15 ). For simplicity,  FIGS. 14 and 15  do not show the backing card  140  or the backing card gap  1210  of  FIGS. 12 and 13 . 
     In addition to, or in lieu of, a barrier zone between the labelling zone and the capture zone, some of the present embodiments may have one more barrier zones at other locations to provide additional time for the sample fluid and other material in the fluid flow to bind with the immobilized molecules at the test line and/or at the control line. In some of these embodiments, the membrane may be made of several separate pieces (as oppose to one continuous piece of material). 
       FIG. 16  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  1600  with multiple barrier zones, according to various aspects of the present disclosure. The lateral flow assay device  1600  may include a housing, which is not shown in  FIG. 16  for simplicity. Similar to the lateral flow assay device  100  of  FIG. 1 , the lateral flow assay device  1600  may include a sample pad  150  in the capture zone, a conjugate pad  110  in the labeling zone, and a wicking pad  120  in the wicking zone. The capture zone of the lateral flow assay device  1600  may include two separate membranes  1615  and  1616 . A test line (or test zone)  125  may be embedded in the membrane  1615 . A control line (or control zone)  130  may be embedded in the membrane  1616 . The sample pad  150 , the conjugate pad  110 , the membranes  1615 - 1616 , the test line  125 , the control line  130 , and the wicking pad  120  of  FIG. 16  may be made of similar material as described above for the corresponding components of  FIG. 1 . 
     With reference to  FIG. 16 , the removable physical barrier  135  between the conjugate pad  110  and the membrane  1615  is substantially similar to the removable physical barrier  135  of  FIG. 1 . The lateral flow assay device  1600  may include a barrier  1630  that may prevent fluid flow from the membrane  1615  and the test line  125  into the membrane  1616 . The lateral flow assay device  1600  may include a barrier  1635  that may prevent fluid flow from the membrane  1616  and the control line  130  into the wicking pad  120 . 
     In some of the present embodiments, the lateral flow assay device  1600  may include a housing that may apply pressure to different components of the lateral flow assay device  1600  in order for these components to come into contact with each other after the barrier between them is removed.  FIG. 17  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  1600  showing a cross section of the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure. With reference to  FIG. 17 , the perspective shows a cross sectional view of the housing  1705  across the surfaces  1706 . 
     Similar to the housing  205  of  FIG. 2 , the housing  1705  of  FIG. 17  may include a sample port  1710  for applying the sample liquid to the sample pad  150 , an opening  1715  for viewing the test line  125 , and (for the embodiments that include a control line) an opening  1720  for viewing the control line  130 . Some embodiments may include one opening for viewing both the test line  125  and the control line  130 . 
     Similar to the housing  205  of  FIG. 2 , the housing  1705  may apply pressure to the conjugate pad  110  (e.g., as shown by the arrows  250 ) and/or to the membrane  115  (e.g., as shown by the arrows  255 ) such that when the barrier  135  is removed, the conjugate pad  110  and the membrane  115  come to contact with each other to allow the fluid material in the flow path to flow from the conjugate pad  110  into the membrane  115  by capillary act. 
     With continued reference to  FIG. 17 , the housing  1700  may apply pressure to the membrane  1616  (e.g., as shown by the arrows  1750 ) and/or to the backing card  140  and the membrane  1615  (e.g., as shown by the arrows  1755 ) such that when the barrier  1630  is removed, the membrane  1616  and the membrane  2085  come to contact with each other to allow the fluid material in the flow path to flow from the membrane  1615  and the test line  125  (which is embedded in the membrane  1615 ) into the membrane  1616  by capillary act. The housing  1600  may apply pressure to the wicking pad  120  (e.g., as shown by the arrows  1760 ) and/or to the backing card  140  and the membrane  1616  (e.g., as shown by the arrows  1765 ) such that when the barrier  1635  is removed, the wicking pad  120  and the membrane  1616  come to contact with each other to allow the fluid material in the flow path to flow from the membrane  1616  and the control line  130  (which is embedded in the membrane  1616 ) into the wicking pad  120  by capillary act. With further reference to  FIG. 17 , the barriers  135 ,  1630 , and  1635  may be removed using any of the mechanisms described above with reference to  FIGS. 3-10  for removing the barrier  135  of  FIG. 3 . 
       FIG. 18  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing the removal of multiple barriers, according to various aspects of the present disclosure. The figure as shown, includes two operational steps  1801  and  1802 . With reference to  FIG. 18 , step  1801  shows an initial state where the barrier  135  is between the conjugate pad  110  and the membrane  115 , the barrier  1630  is between the membrane  1616  and the membrane  1615 , and the barrier  1635  is between the wicking pad  120  and the membrane  1616 . The barriers  135 ,  1630 , and  1635  may be made of materials (e.g., plastic, latex, metal, etc.) which block the fluid material from flowing downstream on the flow path. The barriers&#39; materials are selected from materials that do not react with the fluid material in the flow path. As shown in step  1801 , the barriers  135 ,  1630 , and  1635  are flexible and follow (as shown by the corresponding dashed lines  335 ,  1631 , and  1636 ) the contours of the components that the barriers  135 ,  1630 , and  1635  are separating. 
     In some of the present embodiments, the lateral flow assay device  1800  at the start of a test may include the barriers  135 ,  1630 , and  1635 . For example, the lateral flow assay device  1800  may be manufactured in the configuration shown in step  1801  of  FIG. 18 . A test may start by applying a sample fluid to the conjugate pad  110  (e.g., through the sample port  1710  of  FIG. 17 ). 
     With reference to step  1802  of  FIG. 18 , some of the present embodiments may use several timers for removing the barriers  135 ,  1630 , and  1635 . For example, a first timer may be set to allow the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110 . After the expiration of the first timer, the barrier  135  may be removed (as shown by the arrow  360  of  FIG. 18 ) from between the conjugate pad  110  and the membrane  1615  to allow the fluid material to flow from the conjugate pad  110  into the membrane  1615  by capillary action. 
     With continued reference to  FIG. 18 , after the expiration of the first timer, a second timer may be started to determine the time for removing the barrier  1630 . In some of the present embodiments, the labelled immunocomplex in a sandwich format assay may require more time to bind with the immobilized binding reagent at the test line than the time it takes for the fluid material to flow by capillary action through the test line  125  into the membrane  1616 . The second timer may allow enough time for the binding of the labelled immunocomplex with the immobilized binding reagent at the test line. 
     Similarly, in a competitive assay format, the labelled binding reagent in the fluid may require more time to bind with the immobilized analyte/protein-analyte complex in the test line. The second timer may allow enough time for the binding of the labelled binding reagent with the immobilized binding reagent at the test line. After the expiration of the second timer, the barrier  1630  may be removed (as shown by the arrow  1831 ) from between (i) the membrane  1615 , the test line  125  and (ii) the membrane  1635  to allow the fluid material to flow from the membrane  1615  and the test line  125  into the membrane  1616  by capillary action. 
     After the expiration of the second timer, a third timer may be started to determine the time for removing the barrier  1635 . In some of the present embodiments, the free labeled binding reagents may require more time to bind with the immobilized antibody in a sandwich format assay at the control line than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . Similarly, in a competitive assay format, the free labeled binding reagents may require more time to bind with the immobilized analyte molecule (or a protein-analyte complex) at the control line  130  than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . 
     The third timer may allow enough time for the free labeled binding reagents to bind with the immobilized antibody (in the sandwich assay format) or with the immobilized analyte molecule/protein-analyte complex (in the competitive assay format) at the control line  130 . Similarly, in a competitive assay format, after the expiration of the third timer, the barrier  1635  may be removed (as shown by the arrow  1832 ) from between the membrane  1616 , and the wicking pad  120  to allow the fluid material to flow from the membrane  1616  and the control line  130  into the wicking pad  120  by capillary action. 
     In some of the present embodiments, a separate linear actuator  525  ( FIG. 5 ), solenoid  605  ( FIG. 6 ), or electromagnet  770  ( FIG. 7 ) may be used to remove each of the barriers  135 ,  1630 , and  1635  of  FIG. 16 . In some of the present embodiments, a magnet such as the magnet  405  ( FIG. 4 ) may be attached to each barrier  135 ,  1630 , and  1635  of  FIG. 18  to pull the barrier using a magnet such as magnet  545  ( FIG. 5 ), magnet  615  ( FIG. 6 ), or the core  710  ( FIG. 7 ). 
     In some of the present embodiments, each barrier  135 ,  1630 , and  1635  of  FIGS. 17-18  may have one or more holes such as the hole  805  ( FIG. 8 ) to pull the barrier using a hook such as the hook  905  of  FIG. 9 . In some of the present embodiments, each barrier  135 ,  1630 , and  1635  of  FIGS. 17-18  may have a groove such as the groove  1005  ( FIG. 10 ) to manually pull the barrier. 
     Some of the present embodiments may include only one of the barriers  135 ,  1630 , or  1635  of  FIGS. 16-18 . Other embodiments may include any two of the barriers  135 ,  1630 , or  1635  of  FIGS. 16-18 . Some embodiments (such as the embodiment of  FIGS. 16-18 ) may include all three barriers  135 ,  1630 , or  1635 . In some embodiments, the number of timers may be equal to the number of barriers. Since the fluid flows downstream from the sample pad  150  towards the wicking pad  120 , when a lateral flow assay device has two barriers, the barriers are removed starting with the most upstream barrier followed by the next barrier downstream. When the assay device has three barriers, the barrier  135  is removed first, followed by the barrier  1630 , followed by the barrier  1635 . 
     As described with reference to  FIGS. 12 and 13 , depending on the type of the material used for the conjugate pad  110 , the membrane  115 , and the backing card, and/or the way pads  110  and  115  are placed on the cartridge bed, even when the barrier  135  is in place, some of fluid material may leak from under the conjugate pad  110  (e.g., through the backing card  140  and/or the cartridge bed) into the membrane  115 . With reference to  FIGS. 17-27 , the fluid material may leak from underneath the membrane portion  1615  into the membrane portion  1616  even when the barrier  1630  is in place. The fluid material may also leak from underneath the membrane portion  1616  into the wicking pad  120  even when the barrier  1635  is in place. 
     To prevent such leaks, some embodiments may include a permanent gap in the cartridge bed and/or the backing card  140  in order to prevent the fluid material to leak from under the membrane portion  1615  into the membrane portion  1616  when the barrier  1630  is in place. Some embodiments may include a permanent gap in the cartridge bed and/or the backing card  140  in order to prevent the fluid material to leak from under the membrane portion  1616  into the wicking pad  120  when the barrier  1635  is in place. 
       FIG. 19  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device that includes one or more permanent gaps in the backing card and/or the cartridge bed to prevent the leaking of the fluid material while the corresponding barrier(s) is/are in place, according to various aspects of the present disclosure. 
     With reference to  FIG. 19 , the cartridge bed  171 ,  173 , and  174  may have a gap  1205  such that there is no cartridge bed under a portion of the conjugate pad  110  and the membrane  115  where the barrier  135  is between the conjugate pad  110  and the membrane  115 . In addition, there is a gap  1210  in the backing card  140 . 
     With further reference to  FIG. 19 , the cartridge bed  171 ,  173 , and  174  may have a gap  1910  such that there is no cartridge bed under a portion of the membrane  1615  and a portion of the membrane  1616  where the barrier  1630  is located. The cartridge bed  171 ,  173 , and  174  may have a gap  1915  such that there is no cartridge bed under a portion of the membrane  1616  and a portion of the wicking pad  120  where the barrier  1635  is located. As shown, the cartridge bed may be made of three separate sections  171 ,  173 , and  174 . The three sections of the cartridge bed may be secured on the housing of the lateral flow assay device  100 . 
     With further reference to  FIG. 19 , there may be a gap  1920  in the backing card  140  and/or a gap  1915  in the backing card  140 . In the embodiments that the pads have individual backing cards, each backing card may be made such that the backing card of the pads on the different sides of a gap do not touch each other. 
     In the depicted embodiment, the backing cards do not cross over the cartridge bed gaps  1205 ,  1910 , and  1915 . In other embodiments, a portion of some or all backing cards may cross over a portion of a cartridge bed gap without touching the backing side of the adjacent pad on the other side of the gap. 
     With reference to  FIG. 19 , depending on the type of the test performed by the lateral flow assay device, different embodiments of the lateral flow assay device may include one, two, or all three of the barriers  135 ,  1630 , and  1635 . These embodiments may have the cartridge bed gaps  1205 ,  1910 , and  1915  for the corresponding barriers  135 ,  1630 , and  1635 . In addition to, or in lieu of the cartridge bed gaps  1205 ,  1910 , and  1915 , some of these embodiments may include the backing card gaps  1210 ,  1915 , and  1929  for the corresponding barriers  135 ,  1630 , and  1635 . 
     With reference to  FIGS. 1-19 , the exemplary embodiments were described with reference to pulling the barrier  135  out of the cartridge  575 . In other embodiments, the barrier  135  may not be pulled out of the cartridge  575  at once. Instead, the barrier  135  may be partially pulled out and then pushed back in order to repeatedly bring the conjugate pad  110  and the membrane  115  in touch with each other and then separate from each other. Repeatedly connecting and disconnecting the conjugate pad  110  and the membrane  115  is a technical advantage that may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 . 
     The number of times the barrier  135  is pulled out and pushed back into the cartridge  575 , the duration that the barrier  135  stays in or out of the cartridge  575 , and the time between the pulling and pushing actions may control the amount of contact between the conjugate pad  110  and the membrane  115 . The amount of contact between the conjugate pad  110  and the membrane  115  may in turn be used by the processor  505  to control the flow time (the time it would take for the fluid material to travel the length of the membrane  115 , over the test line  125 , and over the control line  135  to reach the wicking pad  120 ). 
     As a first example, the electric motor  530  and the rotor  570  of  FIG. 5  may be controlled by the processor/comptroller  505  by repeatedly changing the direction of the current through the electric motor, causing the linear moving shaft  540  to partially pull out the barrier  135  out of the cartridge  575  and push beck the barrier  135  into the cartridge  575 . 
     As a second example, the direction of current into the coil  660  of  FIG. 6  may be controlled by the processor/comptroller  505  by repeatedly changing the direction of the current, causing the movable core  610  to partially pull out the barrier  135  out of the cartridge  575  and push beck the barrier  135  into the cartridge  575 . 
     As a third example, the direction of current into the coil  705  of  FIG. 7  may be controlled by the processor/comptroller  505  by repeatedly changing the direction of the current, causing the core  710  to partially pull out the barrier  135  out of the cartridge  575  and push beck the barrier  135  into the cartridge  575 . 
     With reference to  FIGS. 16-19 , a similar technique may be used to repeatedly pull the barrier  1630  and/or the barrier  1635  partially out of the lateral flow assay cartridge (i.e., to partially pull out the barrier from between the two pads that are separated by the barrier) and pushing the barrier back into the cartridge in order to control the time the fluid material comes in contact with the test line  125 , the time the fluid material comes in contact with the control line  130 , and/or the flow rate across the flow path of the lateral flow assay device. Controlling the flow rate of the fluid as it passes over the test line provides the technical advantage of allowing enough binding time at the test line location resulting in increased sensitivity for the test. Similarly, for the control line, the flow rate control provides the technical advantage of allowing enough binding time resulting in stronger signal (color change) at the control line. 
     II. Using Removable Gaps in the Flow Path to Control the Flow and Flow Time 
     Some of the present embodiments may place a gap (instead of a physical barrier) in the barrier zone between the labeling zone and the capture zone. The gap may be placed between the conjugate pad and the membrane to separate the conjugate pad and the membrane until a timer expires. The lateral flow assay may include a housing (e.g., as described below with reference to  FIGS. 20-21 ) that may initially (e.g., prior to the start of a test and for a time period after the start of the test) hold one of the conjugate pad or the membrane pad, preventing the pads from touching each other. In other embodiments, the backing card of conjugate pad or the backing card of the membrane pad may be curved (e.g., as shown in  FIGS. 32 and 33 ) to initially (e.g., prior to the start of a test and for a time period after the start of the test) prevent the pads from touching each other. 
       FIG. 20  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  2000  that has a gap separating the labelling zone and the capture zone, according to various aspects of the present disclosure. The lateral flow assay device  2000  may be similar to the lateral flow assay device  100  of  FIG. 1 , except that the lateral flow assay device  2000  may include a gap  2050  (instead of the physical barrier  135  of  FIG. 1 ) in the barrier zone  2003 . The gap  2050  separates (as shown by the dashed line  2020  and  2025 ) the conjugate pad  110  and the membrane  115 . 
     With reference to  FIG. 20 , the gap  2050  may be substantially occupied by air and may not allow the liquid material to flow from the conjugate pad  110  into the membrane  115 . Other components of the lateral flow assay device  2000  may be similar to the corresponding components of the lateral flow assay device  100  of  FIG. 1 . The lateral flow assay device  2000  may include a housing, which is not shown in  FIG. 20  for simplicity. 
     In some of the present embodiments, the lateral flow assay may include a housing (shown in  FIG. 21 ) that may initially (e.g., prior to the start of a test and for a time period after the start of the test) hold the conjugate pad  110 , preventing the conjugate pad  110  and the membrane  115  from touching each other. The gap created between the conjugate pad  110  and the membrane  115  may then be removed after a time period from the start of the test. 
       FIG. 21  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  2100  showing a cross section of the lateral flow assay device&#39;s housing before and after removing a gap between the labeling zone and the capture zone, according to various aspects of the present disclosure. With reference to  FIG. 21 , the perspective shows a cross sectional view of the housing  170 ,  2105 , and  2106  across the surfaces  2108 - 2109 . Similar to the housing  205  of  FIG. 2 , the housing of  FIG. 21  may include a sample port  210 , an opening  215  for viewing the test line  125 , and an opening  220  for viewing the control line  130 . The figure as shown, includes two operational steps  2101  and  2102 . The housing  2105  may include a cartridge bed  170  for holding the lateral flow assay device&#39;s cartridge. 
     With reference to  FIG. 21 , step  2101  shows an initial state where there is a gap  2050  (same as the gap  2050  of  FIG. 20 ) between the conjugate pad  110  and the membrane  115 . The gap may be maintained by a movable section  2106  of the housing. Since  FIG. 21  shows a cross sectional view of the lateral flow assay device&#39;s  2100  housing, the figure shows a cross section of the movable section  2106  across the surface  2109 . The movable section  2106  may, therefore, substantially extend over the width of the conjugate pad  110  along a surface delimited by line  2175 , as shown in  FIGS. 21 and 22 . 
       FIG. 22  is a top elevational view of the housing of the lateral flow assay device of  FIG. 21 , according to various aspects of the present disclosure. With reference to  FIG. 22 , the top view of the housing  2105 - 2106  shows the sample port  210 , the test line  125  (partially hidden by the housing), the control line  130  (partially hidden by the housing), the opening  215  for viewing the test line  125 , the opening  220  for viewing the control line  130 , and the movable section  2106  of the housing  2105 .  FIG. 22  also shows the approximate extents of the sample pad  150 , the conjugate pad  110 , the membrane  115 , and the wicking pad  120 . 
     With reference to  FIG. 22 , the lower portion of the movable section (shown by the dashed line  2175 , which corresponds to the line  2175  of  FIG. 21 ) is attached to the conjugate pad (e.g., by an adhesive substance such as glue, resin, gum, etc.) and holds the conjugate pad  110  separate from the membrane  115  (as shown in step  2101  of  FIG. 21 ). With reference to  FIG. 22 , the lower portion  2175  of the movable section  2106  may substantially extend over the width of the conjugate pad  110 . 
     With further reference to  FIG. 21 , in some of the present embodiments, a timer may be programmed to allow time for the analyte (if any) in the sample fluid to bind with the labeled binding reagent on the conjugate pad  110 . The timer may be started at the beginning of the test (e.g., substantially at or around the same time as the sample fluid is applied to the sample pad  150 ). The timer may be set such that enough time is allowed for the sample fluid to flow from the sample pad  150  into the conjugate pad  110  and for the analyte (if any) in the sample fluid to bind with the labelled binding reagent on the conjugate pad  110 . 
     After the timer expires, the gap  2050  may be removed from between the conjugate pad  110  and the membrane in order to fluidically connect the conjugate pad  110  in the labeling zone  102  to the membrane  115  in the capture zone  104 . After the conjugate pad  110  and the membrane  115  come to contact with each other, the fluid material in the flow path may flow from the conjugate pad  110  into the membrane  115  by capillary action. 
     In step  2102  of  FIG. 21 , the gap  2050  may be removed (e.g., after the expiration of the timer) from between the conjugate pad  110  and the membrane  115  by moving the movable section  2106  towards the membrane  115  until the conjugate pad  110  and the membrane  115  come into contact with each other. As a first example, the movable section  2106  may be moved towards the membrane  115  using a linear actuator similar to the linear actuator  525  of  FIG. 5  or a solenoid similar to the solenoid  605  of  FIG. 6 . The linear moving shaft  540  of  FIG. 5  may include a surface (e.g., instead of the magnet  545 ) with a shape sufficient for pushing down the movable section  2106  (e.g., with a surface that may be smaller than the outside surface  2190  of the movable section  2106  that is facing outside of the lateral flow assay device  2100 ). 
     At the beginning of a test, the electric motor  530  of  FIG. 5  may be configured to pull the linear moving shaft  545  towards the rotating shaft  580 , and the linear actuator  525  may be placed adjacent to the lateral flow assay device  2100  ( FIG. 21 ) such that the surface  545  on the shaft  540  contacts the outside surface  2190  ( FIG. 21 ) of the movable surface  2106 . 
     After the time required for the analyte in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the electric motor  530  may receive a signal (e.g., from the processor  505 , from a pushbutton, from a toggle switch, etc., as described above with reference to  FIG. 5 ) to extend the linear moving shaft  545  away from the rotating shaft  580  and towards the lateral flow assay device  2100 . As the linear moving shaft  540  is extended towards the lateral flow assay device  100 , the surface  545  on the linear moving shaft  540  pushes the external surface  2190  of the movable section  2106 , causing the gap  2015  to be removed from between the conjugate pad  110  and the membrane  115 . 
     With reference to step  2102  of  FIG. 21 , the movable section  2106  may move in the direction of the arrow  2195  until the surface of the movable section  2106  that is attached to the conjugate pad  110  (e.g., the surface that is delimited by the line  2175  of  FIGS. 21 and 22 ) makes contact with the membrane  115  and removes (as shown by the arrow  2185 ) the gap from between the conjugate pad  110  and the membrane  115 . 
     As a second example, the movable section  2106  of the housing  2105  may be pushed towards the membrane  115  using the solenoid  605  of  FIG. 6 . For example, the movable core  610  may include a surface  615  (e.g., instead of the magnet  615 ) with a shape sufficient for pushing down the movable section  2106  (e.g., with a surface that may be smaller than the outside surface  2190  of the movable section  2106  that is facing outside of the lateral flow assay device  2100 ). 
     At the beginning of a test, the solenoid  605  may be configured (e.g., by changing the direction of electric current in the wire  650 ) to pull the movable core  610  towards the solenoid  605 , and the solenoid  605  may be placed adjacent to the lateral flow assay device  100  ( FIG. 21 ) such that the surface  615  on the movable core  610  contacts the outside surface  2190  ( FIG. 21 ) of the movable surface  2106 . 
     After the time required for the analyte in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the controller circuit  630  may receive one or more signals (e.g., from the processor  505 , a pushbutton, a toggle switch, etc., as described above with reference to  FIG. 6 ) to extend the movable core  610  away from the solenoid  605  and towards the lateral flow assay device  2100 . As the movable core  610  is extended towards the lateral flow assay device  2100 , the surface  615  on the movable core  610  may push the external surface  2190  of the movable section  2106 , causing the gap  2015  to be removed from between the conjugate pad  110  and the membrane  115 . 
     As a third example, one or more magnets may be attached to the upper surface  2190  of the movable section  2106  of the lateral flow assay device  2100 . The core  710  of  FIG. 7  may be placed next to the lateral flow assay device  2100  such that the cross section of the core  710  touches the upper surface  2190  of the movable section  2106  while the switch  750  is open. After the time required for the analyte in the sample fluid to bind with the labeled binding agents on the conjugate pad  110   115  elapses, the controller circuit  730  may receive one or more signals (e.g., from the processor  505 , a pushbutton, a toggle switch, etc., as described above with reference to  FIG. 7 ) to close the switch  750 . The amount and the direction of the current on the wire  750  and the coil  705  may be adjusted such that the magnetic field generated by the core  710  may repel the magnet(s) on the surface  2190  and push the movable section  2106  in the direction of the arrow  2195  until the conjugate pad  110  comes into contact with the membrane  115 . For example, the magnetic field generated by the core  710  may be of the same polarity as the magnet(s) on the surface  2190  in order for the magnets to repel each other. 
     In some of the present embodiments, the lateral flow assay device&#39;s housing may include one or more movable poles, pillars, rods, and/or springs to hold the conjugate pad separate from the membrane to create a gap between the conjugate pad and the membrane.  FIG. 23  is a front elevational view of one example embodiment of a portion of a lateral flow assay device  2300  that may use one or more posts or pillars to create a removable gap between the conjugate pad and the membrane, according to various aspects of the present disclosure. 
     With reference to  FIG. 23 , the lateral flow assay device  2300  may include one or more holes (the cross section of one of the holes is shown as delimited by the lines  2305 ). The hole(s) may go through the cartridge bed  170 , the backing card  140 , and the membrane  115 . 
     The lateral flow assay device  2300 , in some of the present embodiments, may include one or more movable poles, pillars, rods, and/or springs  2310  (referred to herein as the pole or the poles for simplicity). Each movable pole  2310  may go through a hole  2305  to create a gap  2050  between the conjugate pad  110  and the membrane  115  by keeping the conjugate pad  110  at a distance from the membrane  115 , as shown in  FIG. 23 . 
       FIG. 24  is a top elevational view of one example embodiment of the lateral flow assay device of  FIG. 23 , according to various aspects of the present disclosure. With reference to  FIG. 24 , the lateral flow assay device&#39;s  2300  housing is not shown for simplicity. In the example of  FIG. 24 , the lateral flow assay device  2300  includes five holes  2305 . In other embodiments, the lateral flow assay device may include any number of one or more holes  2305 . 
     With reference to  FIG. 24 , there is a pole  2310  in each of the holes  2305 . In the example of  FIG. 24 , the holes  2305  and the poles  2310  have a circular cross section. In other embodiments, the holes  2305  and the poles  2310  may have a triangular, a rectangular, a polygon, or any arbitrary shape cross sections. 
     The poles  2310  may be made of any material (e.g., plastic, metal, glass, etc.) that is capable of holding the conjugate pad  110  separate from the membrane  115  and do not react with the fluid material in the fluid flow. In some of the present embodiments, the poles  2310  may be attached to the conjugate pad  110  by an adhesive substance (e.g., glue, resin, gum, etc.). In other embodiments, the poles  2310  may press against the conjugate pad  110  in order to keep the conjugate pad  110  separate from the membrane  115 . 
     In some of the present embodiments, a timer may be programmed to allow time for the analyte (if any) in the sample fluid to bind with the labeled binding reagent on the conjugate pad  110 . At the beginning of a test, the poles  2310  may be at the position shown in  FIG. 23  to keep the conjugate pad  110  separate from the membrane  115 . The gap  2050  may be substantially filled by air and may prevent the fluid material in the fluid flow to move from the conjugate pad  110  into the membrane  115 . 
     After the timer expires, the poles  2310  of  FIGS. 23-24  may be pulled to bring the conjugate pad  110  into contact with the membrane  115 .  FIG. 25  is a front elevational view of one example embodiment of a portion of a lateral flow assay device  2300  after the gap between the conjugate pad and the membrane is removed, according to various aspects of the present disclosure. 
     With reference to  FIG. 25 , the pole(s)  2310  are pulled in the direction of the arrow  2540  until the conjugate pad  110  and the membrane  115  come in contact with each other to allow the fluid material in the flow path to flow from the conjugate pad  110  into the membrane  115  by capillary act. 
     In some of the present embodiments, one or more pieces of magnet  2550  ( FIG. 25 ) may be attached to the poles  2310  of  FIGS. 23-25  on the surface of the poles that is facing outside of the housing  2505 . The poles  2310  may be pulled down using a linear actuator similar to the linear actuator  525  (as described above with reference to  FIG. 5  for pulling the barrier  135 ), a solenoid similar to the solenoid  606  (as described above with reference to  FIG. 6  for pulling the barrier  135 ), or an electromagnet  770  (as described above with reference to  FIG. 7  for pulling out the barrier  135 ). 
     For example, with reference to  FIG. 5 , at the beginning of a test, the electric motor  530  may be configured to extend the linear moving shaft  545  away from the rotating shaft  580 , and the linear actuator  525  may be placed adjacent to the lateral flow assay device  2300  ( FIG. 25 ) such that the magnet(s)  545  on the shaft  540  may contact the magnet(s)  2550  ( FIG. 25 ) on the pole  2550 . In the embodiments that the lateral flow assay device  2300  includes more than one pole  2310 , the magnet  545  on the shaft  540  may be large enough to make contact with the magnet  2550  of all poles  2310 . Alternatively, there may be multiple magnets  545  on the shaft  540  to come in contact with the magnets on the poles  2550 . 
     After the time required for the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the electric motor  530  may receive a signal to pull the linear moving shaft  545  back towards the rotating shaft  580  and away from the lateral flow assay device  2300 . As the linear moving shaft  540  is pulled away from the lateral flow assay device  2300 , the magnet(s)  545  on the linear moving shaft  540  pull(s) the magnet(s)  2550  (which is firmly attached to the pole(s)  2310 ), causing the pole(s)  2310  to move in the direction of the arrow  2540  until the conjugate pad  110  comes in contact with the membrane  115 . The magnets  545  and  2550  may have the polarities (e.g., opposite polarities to attract each other) and enough magnetic force to allow them to connect to each other (e.g., by magnetic force) and to continue connecting to each other while the pole  2310  is being pulled through the hole  2305 . After the conjugate pad  110  comes in contact with the membrane  115 , the gap  2050  of  FIG. 23  is removed and the fluid may flow from the conjugate pad  110  into the membrane  115  by capillary act. 
     The pole(s)  2310  may be pulled using the solenoid  605  of  FIG. 6 . With reference to  FIG. 6 , at the beginning of a test, the solenoid  605  may be configured to extend the movable core  610  away from the solenoid  605 , and the solenoid  605  may be placed adjacent to the lateral flow assay device  2300  ( FIG. 25 ) such that the magnet(s)  615  on the movable core  610  may contact the magnet  2550  ( FIG. 25 ) on the pole  2550 . In the embodiments that the lateral flow assay device  2300  includes more than one pole  2310 , the magnet  615  on the movable core  610  may be large enough to make contact with the magnet  2550  of all poles  2310 . Alternatively, there may be multiple magnets  615  on the movable core  610  to come in contact with the magnets on the poles  2550 . 
     After the time required for the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the controller circuit  630  may receive a signal to pull the movable core  610  back towards the solenoid  605  and away from the lateral flow assay device  2300 . As the movable core  610  is pulled away from the lateral flow assay device  2300 , the magnet(s)  615  on the movable core  610  may pull the magnet(s)  2550  (which is/are firmly attached to the pole(s)  2310 ), causing the pole(s)  2310  to move in the direction of the arrow  2540  until the conjugate pad  110  comes in contact with the membrane  115 . The magnets  615  and  2550  may have the polarities (e.g., opposite polarities to attract each other) and enough magnetic force to allow them to connect to each other (e.g., by magnetic force) and to continue connecting to each other while the pole  2310  is being pulled through the hole  2305 . After the conjugate pad  110  comes in contact with the membrane  115 , the gap  2050  of  FIG. 23  is removed and the fluid may flow from the conjugate pad  110  into the membrane  115  by capillary act. 
     The pole(s)  2310  may be pulled using the electromagnet  770  of  FIG. 7 . The core  710  of  FIG. 7  may be placed next to the lateral flow assay device  2300  ( FIG. 25 ) such that the cross section of the core  710  is a distance “d2” away from the magnet  2550  while the switch  750  is open. The distance “d2” may be substantially the same as the height of the gap between the conjugate pad  110  and the membrane  115  (e.g., the distance required to pull the conjugate pad  110  towards the membrane  115 ) in order for the conjugate pad  110  and the membrane  115  to contact each other. 
     After the time required for the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110  elapses, the controller circuit  730  may receive one or more signals (e.g., from the processor  505 , a pushbutton, a toggle switch, etc., as described above with reference to  FIG. 7 ) to close the switch  750 . The amount and the direction of the current on the wire  750  and the coil  705  may be adjusted such that the magnet generated by the core  710  may attract the magnet(s)  2550  on the pole(s)  2310  and pull the pole(s)  2310  in the direction of the arrow  2540  until the conjugate pad  110  comes into contact with the membrane  115 . For example, the magnet generated by the core  710  may be of the opposite polarity as the magnet(s)  2550  in order for the magnets to attract each other. After the conjugate pad  110  comes in contact with the membrane  115 , the gap  2050  of  FIG. 23  is removed and the fluid may flow from the conjugate pad  110  into the membrane  115  by capillary act. 
       FIG. 26  is a flowchart illustrating an example process  2600  for removing a gap that separates the labeling and capture zones of a lateral flow assay device, according to various aspects of the present disclosure. In some of the present embodiments, the process  2600  may be performed by a processor  505  ( FIGS. 5-7 ). 
     With reference to  FIG. 26 , the process  2600  may send (at block  2605 ) one or more signals to a device to adjust the position of the device with respect to the lateral flow assay device  2300  ( FIGS. 23-25 ) and/or to set up the device to remove the gap  2050  of the lateral flow assay device  2300 . 
     As a first example, the processor  505  (as described above with reference to  FIGS. 5 and 21-22 ) may send one or more signals to the electric motor  530  to rotate and cause the rotational to linear movement converter  535  to move the linear moving shaft  540  a predetermined distance in order to make a contact between the linear moving shaft  540  and the upper surface  2190  of the movable section  2106  of the housing  2105 . 
     As a second example, the processor  505  (as described above with reference to  FIGS. 6 and 21-22 ) may send one or more signals to the controller circuit  630  to move the movable core  610  a predetermined distance in order to make a contact between the movable core  610  and the upper surface  2190  of the movable section  2106  of the housing  2105 . As a third example, the processor  505  (as described above with reference to  FIGS. 7 and 21-22 ) may send one or more signals to the controller circuit  730  to turn off the switch  750  and prevent the core  710  to act as a magnet while the core  710  is contacting the top surface  2190  of the movable section  2116 . 
     As a fourth example, the processor  505  of  FIG. 5  may send one or more signals to the electric motor  530  to rotate the rotating shaft  580  to cause the linear moving shaft  540  to move such that the magnet(s)  545  on the linear moving shaft  540  come(s) in contact with the magnet(s)  2550  ( FIG. 25 ) on pole(s)  2310 . 
     As a fifth example, the processor  505  of  FIG. 6  may send one or more signals to the controller circuit  630  to adjust the electric current in the wire  650  and the coil  660  such that the magnet(s)  615  on the movable core  610  come(s) in contact with the magnet(s)  2550  ( FIG. 25 ) on pole(s)  2310 . As a third example, the processor  505  of  FIG. 7  may send one or more signals to the controller circuit  730  to turn off the switch  750  in order for the core  710  not to act as a magnet. 
     As a sixth example, the processor  505  (as described above with reference to  FIGS. 7 and 23-25 ) may send one or more signals to the controller circuit  730  to turn off the switch  750  and prevent the core  710  to act as a magnet while the core  710  is kept at a distance “d2” from the magnet(s)  2550  on the pole(s)  2310 . 
     With further reference to  FIG. 26 , the process  2600  may receive (at block  2610 ) a signal that includes a value to set a timer for removing the barrier. The signal, in some embodiments, may include a value that indicates the amount of time in a predetermined unit of time (e.g., hours, minutes, seconds, milliseconds, microseconds, etc.). The signal, in some embodiments, may include a value and a unit of time. In some embodiments, the process  2600  may receive, at the processor  505  ( FIGS. 5-7 ), a signal that includes the timer value from the client device  515 . In some embodiments, the processor  505  may be associated with and communicatively coupled to a user interface including a keyboard and a display. In these embodiments, the process  2600  may receive, at the processor  505 , the signal that includes the timer value from the keyboard associated with the processor. 
     With continued reference to  FIG. 26 , the process  2600  may then set (at block  2615 ) set a timer to expire after a time period that is identified by the received value. For example, the processor  505  may set an internal timer to expire after a time period determined by the received timer value. The process  2600  may then determine (at block  2620 ) whether to start the timer. 
     In some of the present embodiments, the process  2600  may receive a signal to start the timer, which is different that the signal that includes the timer value. For example, the client device  515  ( FIGS. 5-7 ) may receive a signal through the application executing on the client device  515  indicating the start of the test. The process  2600  may then receive a signal, at the processor  505 , from the client device  515  indicating the start of the test. Alternatively, the process  2600  may receive the signal after a physical switch (e.g., a push button or a toggle switch) that is communicatively coupled to the processor  505  is activated to generate the signal. In some of the present embodiments, the process  2600  may start the timer as soon as the timer value is set (at block  2615 ). These embodiments may bypass block  2620 . 
     When the process  1100  determines (at block  2620 ) that the timer should not be started, the process  2600  may proceed back to block  2620 . Otherwise, the process  2600  may start (at block  2625 ) the timer. The process  2600  may then determine (at block  2630 ) whether the timer has expired. When the process  2600  determines (at block  2630 ) that the timer has not expired, the process  2600  may proceed back to block  2630  to wait for the timer to expire. 
     Otherwise, the process  2600  may send (at  2635 ) one or more signals to remove the gap by bringing together the labeling and capture zones of the lateral flow assay device. The process  2600  may then end. As a first example, as described above with reference to  FIGS. 5 and 21-22 , the processor  505  may send one or more signals to the electric motor  530  to rotate and cause the rotational to linear movement converter  535  to move the linear moving shaft  540  a predetermined distance in order to move the movable section  2106  of the housing  2105  in the direction of the arrow  2195  in order to make a contact between the conjugate pad  110  and the membrane  115 . 
     As a second example, as described above with reference to  FIGS. 6 and 21-22 , the processor  505  may send one or more signals to the controller circuit  630  to change the direction of the electric current in the wire  650  and cause the movable core  610  to move a predetermined distance in order to move the movable section  2106  of the housing  2105  in the direction of the arrow  2195  in order to move the movable section  2106  of the housing  2105  in the direction of the arrow  2195  and make a contact between the conjugate pad  110  and the membrane  115 . 
     As a third example, as described above with reference to  FIGS. 7 and 21-22 , the processor  505  may send one or more signals to the controller circuit  730  to close the switch  750  and cause the core  710  to act as a magnet and repel the magnet(s) on the top surface  2190  of the movable section  2116  in order to move the movable section  2106  of the housing  2105  in the direction of the arrow  2195  and make a contact between the conjugate pad  110  and the membrane  115 . 
     As a fourth example, as described above with reference to  FIGS. 5 and 23-25 , the processor  505  may send one or more signals to the electric motor  530  to rotate and cause the rotational to linear movement converter  535  to move the linear moving shaft  540  a predetermined distance in order to move the pole(s)  2310  in the direction of the arrow  2540  ( FIG. 25 ) in order to make a contact between the conjugate pad  110  and the membrane  115 . As a fifth example, as described above with reference to  FIGS. 6 and 23-25 , the processor  505  may send one or more signals to the controller circuit  630  to change the direction of the electric current in the wire  650  and cause the movable core  610  to move a predetermined distance in order to move the pole(s)  2310  in the direction of the arrow  2540  ( FIG. 25 ) to make a contact between the conjugate pad  110  and the membrane  115 . 
     As a sixth example, as described above with reference to  FIGS. 7 and 23-25 , the processor  505  may send one or more signals to the controller circuit  730  to close the switch  750  and cause the core  710  to act as a magnet and attract the magnet(s)  2550  on the pole(s)  2310  in order to move the pole(s)  2310  in the direction of the arrow  2540  ( FIG. 25 ) to make a contact between the conjugate pad  110  and the membrane  115 . 
     Some of the present embodiments may place gaps (instead of a physical barriers) between different components of the lateral flow assay device. In addition to, or in lieu of, a gap between the labelling zone and the capture zone, some of the present embodiments may have one or more gaps at other locations to provide additional time for the fluid material in the fluid flow to have additional time to bind with the immobilized molecules at the test line and/or at the control line. In some of these embodiments, the membrane may be made of several separate pieces (as oppose to one continuous piece of material). The gaps may be substantially filled with air. 
       FIG. 27  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device  2700  with multiple gaps separating different components of the lateral flow assay device, according to various aspects of the present disclosure. The lateral flow assay device  2700  may include a housing that is not shown in  FIG. 27  for simplicity. The lateral flow assay device  2700  may be similar to the lateral flow assay device  1600  of  FIG. 16 , except that the lateral flow assay  2700  may include gaps (instead of the physical barriers) to separate different components of the lateral flow assay device  2700 . 
     With reference to  FIG. 27 , the gap  2015  between the conjugate pad  110  and the membrane  1615  is substantially similar to the gap  2015  of  FIG. 20 . The lateral flow assay device  2700  may include a gap  2750  separating the membranes  1615  and  1616  (as shown by the dashed lines  2751 - 2752 ) that may prevent fluid flow from the membrane  1615  and the test line  125  into the membrane  1616 . The lateral flow assay device  2700  may include a gap  2755  separating the membrane  1616  and the wicking pad  120  (as shown by the dashed lines  2756 - 2757 ) that may prevent fluid flow from the membrane  1616  and the control line  130  into the wicking pad  120 . 
     In some of the present embodiments, the lateral flow assay may include a housing that may initially (e.g., prior to the start of a test and for a time period after the start of the test) hold different components of the lateral flow assay device separate from each other to maintain the gaps  2050 ,  2750 , and  255 .  FIG. 28  is an upper front perspective view of one example embodiment of a portion of a lateral flow assay device showing a cross section of the lateral flow assay device&#39;s housing before and after removing multiple gaps, according to various aspects of the present disclosure. 
     With reference to  FIG. 28 , the perspective shows a cross sectional view of the housing  2805 - 2308  across the surfaces  2811 - 2314 . Similar to the housing of  FIG. 17 , the housing  2805 - 2308  of  FIG. 28  may include a sample port  1710 , an opening  1715  for viewing the test line  125 , and an opening  1720  for viewing the control line  130 . 
     The figure as shown, includes two operational steps  2801  and  2802 . With reference to  FIG. 28 , step  2801  shows an initial state where there may be a gap  2050  (same as the gap  2050  of  FIG. 17 ) between the conjugate pad  110  and the membrane  1615 . The gap  2050  may be maintained by a movable section  2806  of the housing. There may be a gap  2750  (same as the gap  2750  of  FIG. 17 ) between the membrane  1615  and the membrane  1616 . The gap  2750  may be maintained by a movable section  2807  of the housing. There may be a gap  2755  (same as the gap  2755  of  FIG. 17 ) between the membrane  1616  and the wicking pad  120 . The gap  2755  may be maintained by a movable section  2106  of the housing. The gap  2755  may be maintained by a movable section  2808  of the housing. 
     Since  FIG. 28  shows a cross sectional view of the lateral flow assay device&#39;s  2700  housing, the figure shows a cross section of the movable sections  2806 ,  2807 , and  2808  across the surfaces  2812 ,  2813 , and  2814 , respectively. The movable sections  2806 ,  2807 , and  2808  may substantially extend over the width of the lateral flow assay device  2700  similar to what was described above with reference to  FIGS. 21 and 22  for section  2106 . 
     With reference to step  2802  of  FIG. 28 , some of the present embodiments may use several timers for removing the gaps  2050 ,  2750 , and  2755  of  FIG. 28 . For example, a first timer may be set to allow the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110 . After the expiration of the first timer, the gap  2050  may be removed by moving (as shown by the arrow  2891 ) the movable section  2806  towards the membrane  1615  until the conjugate pad  110  and the membrane  1615  come into contact with each other. After the conjugate pad  110  and the membrane  1615  come to contact with each other, the fluid material in the flow path may flow from the conjugate pad  110  into the membrane  1615  by capillary action. 
     With continued reference to  FIG. 28 , after the expiration of the first timer, a second timer may be started to determine the time for removing the gap  2750 . In some of the present embodiments, the labelled immunocomplex in a sandwich format assay may require more time to bind with the immobilized binding reagent at the test line than the time it takes for the fluid material to flow by capillary action through the test line  125  into the membrane  1616 . The second timer may allow enough time for the binding of the labelled immunocomplex with the immobilized binding reagent at the test line. Similarly, in a competitive assay format, the labelled binding reagent in the fluid may require more time to bind with the immobilized analyte/protein-analyte complex in the test line. The second timer may allow enough time for the binding of the labelled binding reagent with the immobilized binding reagent at the test line. 
     After the expiration of the second timer, the gap  2750  may be removed by moving (as shown by the arrow  2892 ) the movable section  2807  towards the membrane  1615  until the membrane  1616  and the membrane  1615  come into contact with each other. After the membrane  1616  and the membrane  1615  come to contact with each other, the fluid material in the flow path may flow from the membrane  1615  into the membrane  1616  by capillary action. 
     After the expiration of the second timer, a third timer may be started to determine the time for removing the gap  2755 . In some of the present embodiments, the free labeled binding reagents may require more time to bind with the immobilized antibody in a sandwich format assay at the control line than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . Similarly, in a competitive assay format, the free labeled binding reagents may require more time to bind with the immobilized analyte molecule (or a protein-analyte complex) at the control line  130  than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . 
     The third timer may allow enough time for the free labeled binding reagents to bind with the immobilized antibody (in the sandwich assay format) or with the immobilized analyte molecule/protein-analyte complex (in the competitive assay format) at the control line  130 . Similarly, in a competitive assay format. After the expiration of the third timer, the gap  2755  may be removed by moving (as shown by the arrow  2893 ) the movable section  2808  towards the membrane  1616  until the wicking pad  120  and the membrane  1616  come into contact with each other to allow the fluid material to flow from the membrane  1616  and the control line  130  into the wicking pad  120  by capillary action. 
     The movable sections  1250 ,  2750 , and  2755  of the housing may be moved by mechanisms such as a linear actuator  525  ( FIG. 5 ), a solenoid  615  ( FIG. 6 ), or an electromagnet  770  ( FIG. 7 ) as described above with reference to the lateral flow assay  2100  of  FIG. 21 . 
     Some of embodiments may include a housing with a one or more sets of holes. Each hole may include a pole for maintaining one of the gaps in the barrier zone of the lateral flow assay device.  FIG. 29  is a front elevational view of one example embodiment of a portion of a lateral flow assay device  2900  that may use multiple posts or pillars to create removable gaps between different components of the lateral flow assay device, according to various aspects of the present disclosure. 
     As shown, the lateral flow assay device  2900  may include one or more set of holes (the cross section of one of the holes is shown as delimited by the lines  2305 ,  2906 , and  2907 ). The lateral flow assay device  2900 , in some of the present embodiments, may include one or more sets of movable poles (or pillars)  2310 ,  2911 , and  2912 . Each movable pole  2310  may go through a hole  2305  to create the gap  2050  between the conjugate pad  110  and the membrane  1615  by keeping the conjugate pad  110  at a distance from the membrane  1615 , as shown in  FIG. 29 . 
     Each movable pole  2911  may go through a hole  2906  to create the gap  2750  between the membrane  1615  and the membrane  1616  by keeping the membrane  1616  at a distance from the membrane  1615 , as shown in  FIG. 29 . Each movable pole  2912  may go through a hole  2907  to create the gap  2755  between the membrane  1616  and the wicking pad  120  by keeping the wicking pad  120  at a distance from the membrane  1616 , as shown in  FIG. 29 . 
       FIG. 30  is a top elevational view of one example embodiment of the lateral flow assay device of  FIG. 29 , according to various aspects of the present disclosure. With reference to  FIG. 30 , the lateral flow assay device&#39;s  2700  housing is not shown for simplicity. In the example of  FIG. 30 , the lateral flow assay device  2700  includes three sets of three holes  2305 ,  2911 , and  2912 . In other embodiments, the lateral flow assay device may include any number of holes in each set of holes  2305 ,  2906 , and  2907 . In the example of  FIG. 29 , the holes  2305 ,  2906 , and  2907  and the poles  2310 ,  2911 , and  2912  have a circular cross section. In other embodiments, the holes  2305 ,  2906 , and  2907  and the poles  2310 ,  2911 , and  2912  may have a triangular, a rectangular, a polygon, or any arbitrary shape cross sections. The poles  2310 ,  2911 , and  2912  may be made of any material (e.g., plastic, metal, glass, etc.) that is capable of holding the components of the lateral flow assay device separate from each other (as described below) and do not react with the fluid material in the fluid flow. 
     With reference to  FIG. 30 , the holes  2305  and the poles  2310  are substantially similar to the holes  2305  and the poles  2310  of  FIG. 24 . In some of the present embodiments, the poles  2310  may be attached to the conjugate pad  110  by an adhesive substance (e.g., glue, resin, gum, etc.) to keep the conjugate pad  110  separate from the membrane  1615 . In other embodiments, the poles  2310  may press against the conjugate pad  110  in order to keep the conjugate pad  110  separate from the membrane  1615 . 
     With further reference to  FIG. 29 , each pole  2911  may go through a hole  2906 . Each pole  2911  may be attached to the membrane  1616  by an adhesive substance (e.g., glue, resin, gum, etc.) to keep the membrane  1616  separate from the membrane  1615 . In other embodiments, the poles  2911  may press against the membrane  1616  in order to keep the membrane  1616  separate from the membrane  1615 . 
     With continued reference to  FIG. 29 , each pole  2912  may go through a hole  2907 . Each pole  2912  may be attached to the wicking pad  120  by an adhesive substance (e.g., glue, resin, gum, etc.) to keep the wicking pad  120  separate from the membrane  1616 . In other embodiments, the poles  2912  may press against the wicking pad  120  in order to keep the wicking pad  120  separate from the membrane  1616 . 
       FIG. 31  is a front elevational view of one example embodiment of a portion of a lateral flow assay device  2900  after several gaps are removed between different components of the lateral flow assay device, according to various aspects of the present disclosure. With reference to  FIG. 31 , some of the present embodiments may use several timers for removing the gaps  2050 ,  2750 , and  2755 . For example, a first timer may be set to allow the analyte (if any) in the sample fluid to bind with the labeled binding agents on the conjugate pad  110 . After the expiration of the first timer, the gap  2050  may be removed by pulling down the pole(s)  2310  (as shown by the arrow  3131 ) until the conjugate pad  110  and the membrane  1615  come into contact with each other. After the conjugate pad  110  and the membrane  1615  come to contact with each other, the fluid material in the flow path may flow from the conjugate pad  110  into the membrane  1615  by capillary action. 
     With continued reference to  FIG. 31 , after the expiration of the first timer, a second timer may be started to determine the time for removing the gap  2750 . In some of the present embodiments, the labelled immunocomplex in a sandwich format assay may require more time to bind with the immobilized binding reagent at the test line than the time it takes for the fluid material to flow by capillary action through the test line  125  into the membrane  1616 . The second timer may allow enough time for the binding of the labelled immunocomplex with the immobilized binding reagent at the test line. Similarly, in a competitive assay format, the labelled binding reagent in the fluid may require more time to bind with the immobilized analyte/protein-analyte complex in the test line. The second timer may allow enough time for the binding of the labelled binding reagent with the immobilized binding reagent at the test line. 
     After the expiration of the second timer, the gap  2750  may be removed by pulling down the pole(s)  2911  (as shown by the arrow  3132 ) until the membrane  1616  and the membrane  1615  come into contact with each other. After the membrane  1616  and the membrane  1615  come to contact with each other, the fluid material in the flow path may flow from the membrane  1615  into the membrane  1616  by capillary action. 
     After the expiration of the second timer, a third timer may be started to determine the time for removing the gap  2755 . In some of the present embodiments, the free labeled binding reagents may require more time to bind with the immobilized antibody in a sandwich format assay at the control line than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . Similarly, in a competitive assay format, the free labeled binding reagents may require more time to bind with the immobilized analyte molecule (or a protein-analyte complex) at the control line  130  than the time it takes for the fluid material to flow by capillary action through the control line  130  into the wicking pad  120 . 
     The third timer may allow enough time for the free labeled binding reagents to bind with the immobilized antibody (in the sandwich assay format) or with the immobilized analyte molecule/protein-analyte complex (in the competitive assay format) at the control line  130 . Similarly, in a competitive assay format. After the expiration of the third timer, the gap  2755  may be removed by pulling down the pole(s)  2912  (as shown by the arrow  3133 ) until the wicking pad and the membrane  1616  come into contact with each other to allow the fluid material to flow from the membrane  1616  and the control line  130  into the wicking pad  120  by capillary action. 
     The poles  2310 ,  2911 , and  2912  may be moved by mechanisms such as a linear actuator  525  ( FIG. 5 ), a solenoid  615  ( FIG. 6 ), or an electromagnet  770  ( FIG. 7 ) as described above with reference to the lateral flow assay  2300  of  FIGS. 23-24 . Some of the present embodiments may include only one of the gaps  2015 ,  2750 , or  2755  of  FIG. 27 . Other embodiments may include any two of the gaps  2015 ,  2750 , or  2755  of  FIG. 27 . Some embodiments (such as the embodiment of  FIG. 27 ) may include all three gaps  2015 ,  2750 , or  2755 . In some embodiments, the number of timers to remove the gaps may be equal to the number of gaps. Since the fluid flows downstream from the sample pad  150  towards the wicking pad  120 , when a lateral flow assay device has two gaps, the gaps are removed starting with the most upstream gap followed by the next gap downstream. When the assay device has two or three gaps, the existing gaps are removed in the following order: gap  2015  is removed first, followed by the gap  2750 , followed by the gap  2755 . 
     In some embodiments, the backing card of conjugate pad or the backing card of the membrane pad may be curved to initially (e.g., prior to the start of a test and for a time period after the start of the test) prevent the pads from touching each other.  FIG. 32  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  3200  that removes gaps by a spring mechanism, according to various aspects of the present disclosure.  FIG. 33  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 32 , according to various aspects of the present disclosure. 
     With reference to  FIGS. 32 and 33 , the lateral flow assay device  3200  may include a housing  3230 , a sample input port  3220 , and a clear cover  3205  to view the results on the test line  125  and the control line  130 . The disposable cartridge of the lateral flow assay device  3200  may include an NFC chip  590 . The NFC chip  590  may identify the test and other parameters and information related to the test, including but not limited to, the conjugation time on the conjugate pad and the flow time, which is the time it should take for the sample fluid to flow from the point the sample is applied through the sample input port  3220  to the wicking pad  120 . 
     The lateral flow assay device  3200  may include an NFC reader (not shown), such as the NFC reader  595  of  FIGS. 5-7 . When the cartridge is placed in the lateral flow assay device, the NFC reader automatically detects the presence of the NFC tag  590 , reads the information and parameters of the test, and sends the information and parameters to a processor or controller (e.g., the processor/controller  505  of  FIG. 33 ) of the lateral flow device  3200 . The processor/controller may use the information and the parameters to perform the test. The processor/controller may display a portion of the information or parameters on a display of the lateral flow assay device (e.g., on a display of the UI  550  of  FIG. 33 ). The processor/controller may send a portion of the information or parameters to an electronic device external to the lateral flow assay device. 
     When the sample is blood and the test needs plasma separation, the disposable cartridge may include the optional plasma separator filter  1420 . The plasma separator filter  1420  may be located over the conjugate pad  110  between the sample input port  3220  and the conjugate pad  110 . Once the sample is added, a start button either on the device&#39;s UI (e.g., on a keyboard or a touch screen) or a button on the device&#39;s housing may be pushed to start the test. This may also start a timer for the conjugation time. Alternatively, a signal to start the test may be received by the processor of the lateral flow assay device  3200  from an electronic device (e.g., a client device) external to the lateral flow assay device  3200 . 
     After the sample is applied, the sample flows on the conjugate pad  110  and starts mixing and interacting with the conjugate chemicals on the conjugate pad  110 . As shown in  FIGS. 32 and 33 , a gap  3291  may initially be maintained between the conjugate pad  110  and the membrane  115 . Similarly, a gap  3292  may initially be maintained between the membrane  115  and the wicking pad. The gaps  3291  and  3292  may be substantially filled by air. Accordingly, unlike the conventional flow lateral assay cartridges and systems, the conjugate pad  110  is not touching the membrane  115 . The conjugate pad  110  is held away from the membrane  115  by the spring  3241  (e.g., a thin flat metal, such as steel, with a bend  3271  at the base  3272 ) that is attached to the clear backing  3211  of the conjugation pad  110 . Although a clear backing may be used, especially for the membrane, so the colored test and control lines may be seen from both side, it should be understood that at least a portion of the backing, in some embodiments, may be opaque. The conjugate pad  110 , the backing  3211 , and the spring  3241  may be connected to the housing  3230  by a pin or screw  3288 . The spring  3241  may be anchored to the housing  3230  by a pin or screw  3289 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the solenoid  3251  may be activated by a command from the processor/controller  505  ( FIG. 33 ), which may cause the solenoid shaft  3221  to push on the spring  3241  and make the conjugate pad  110  touch the membrane  115  to allow the flow of the fluid material from the conjugate pad  110  to the membrane  115 . 
     The solenoid  3251  may function as a transducer that converts energy into linear motion. The solenoid  3251  may include an electromagnetically inductive coil  3365  ( FIG. 33 ) that is wrapped around the movable solenoid shaft (or armature)  3221 . When an electric current passes through the wire  3360  of  FIG. 33 , a magnetic field is generated by the coil  3365  that causes the moveable shaft  3221  to move in a linear line. By changing the direction of the current, the magnetic field is reversed that causes the solenoid shaft (or armature)  3221  to move in the opposite direction. If a spring loaded solenoid is used, there may be no need to reverse the direction of the current as removing the current (zero current) causes the solenoid to return to its original position via the spring on its shaft. The use of the spring loaded solenoid provides the advantage that the spring loaded solenoid does not draw any current and does not consume any energy in the off position, resulting in much longer battery life for battery-operated lateral flow assay devices. 
     The solenoid  3251  may be repeatedly activated and deactivated to push the solenoid shaft  3221  against the spring  3241  to bring the conjugate pad  110  and the membrane  115  in touch with each other, followed by pulling the solenoid shaft  3221  away from the spring  3241  to cause the spring  3241  to separate the conjugate pad  110  from the membrane  115 . Repeatedly connecting and disconnecting the conjugate pad  110  and the membrane  115  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 . 
     The processor/controller  505  may generate signals (e.g., and without limitations, a set of pulses) to activate the solenoid  3251  according to an algorithm. The processor may use three parameters to control the flow time of the fluid from the time the sample fluid starts flowing at the beginning of the membrane  115  (i.e., the intersection of the conjugate pad  110  and the membrane  115 ) to the time the fluid reaches the wicking pad  120 . The three parameters are the number of times the conjugate pad and the membrane pad are connected (or disconnected), the duration of each connections, and the duration of each disconnection (or the time between consecutive connection and disconnections). 
     The longer the duration of each connection, the more fluid is transferred from the conjugate pad  110  to the membrane  115 . These three parameters may be calculated by the processor  505  using an algorithm and a set of calibration tables or calibration curves. The algorithm input may be the desired conjugation time and flow time, which may be, for example, programmed into the NFC tag  590  at manufacturing. The algorithm input may also include one or more parameters related to the paper material used in the cartridge pads, as described below. 
     The conjugation time may be controlled by a timer. The conjugate time may be received by the processor (e.g., and without limitations, from the NFC chip  950 , from a client device, from the UI  550 , etc.). The processor  505  may also receive a signal (e.g., and without limitations, from a client device, from the UI  550 , from a switch or button on the lateral flow device&#39;s housing, etc.) indicating the start of the test. The processor  505  may measure the elapsed time since the start of the test. After the elapse of the specified conjugation time from the start of the test, the processor  505  may activate the solenoid (or an electromagnet, a servo, a linear actuator, or other mechanism used for bringing the conjugate pad and the membrane pad together). 
     Unlike the membrane  115 , the test line  125 , and the control line  130 , the conjugate pad  110 , in some embodiments, may not need any flow rate control. The flow rate for the membrane pad and the flow time (which is the time it takes for the solution to travel from one end of the membrane to the other) may be controlled by on-off cycling (pulsing) of the mechanism (e.g., and without limitations, the solenoid, the electromagnet, the servo, the linear actuator) that brings the conjugate pad and the membrane pad together. The flow time may be controlled with the time that the pads are connected (Tc) and the time that the pads are disconnected (Td). The value of these parameters and the number of times the pads are connected and disconnected may be determined via an algorithm that uses calibration tables or calibration curves as described below. 
     The calibration curves or tables may be generated by a number of controlled experiments for the type of membrane paper material used by the desired test to be performed by the lateral flow assay cartridge and the lateral flow assay device.  FIG. 34  illustrates an example of a number of curves generated for a particular membrane paper material for a range of connection time (Tc) and disconnection time (Td) of the conjugate pad and the membrane, according to various aspects of the present disclosure. In order to generate the curves  3400 , Tc and Td are varied and the time it takes for the solution to travel from one end of the membrane pad  115  to the other is measured and recorded. This process may be repeated for a large number (e.g., and without limitations, tens, hundreds, thousands, etc.) of Tc and Td values in a specified range. 
     The example of  FIG. 34  shows curves that are generated for the values of Tc ranging from 160 milliseconds (mSec.) to 1000 mSec., and Td ranging from 1 Sec. to 8 Sec. The exemplary curves  3400  were generated for a total of 56 points. The horizontal axis  3405  shows the values of Tc. The vertical axis  3410  shows the flow time (in mSec.) as a function of the Tc time for each of eight different values  3415  of Td used for this particular calibration operation (one curve is generated for each Td). 
     When a desired flow time is specified for a test that a cartridge is made for, the algorithm uses the flow time value to calculate the proper Tc and Td from the calibration curves  3400 .  FIG. 35  illustrates an example of selecting the connection and disconnection times of the conjugate and membrane pads for a specified flow time, according to various aspects of the present disclosure. In the example of  FIG. 35 , the specified flow time is 400 Seconds. 
     With reference to  FIG. 35 , the intersection points  3541 - 3544  of the horizontal line  3550  representing the 400 Sec. time on the vertical axis  3410  with the curves  3500  are calculated. For example, one or more calibration tables may store the values corresponding to the curves  3400  and the values in the table may be searched and/or interpolated/extrapolated to identify the intersection points  3541 - 3544 . 
     In the example of  FIG. 35 , points  3541 - 3544  correspond to the different combinations of (Tc, Td) pairs that may achieve the specified flow time. The algorithm may consider the slope of each curve at the intersection points  3541 - 3544  and pick the one with the smallest slope as that results in the smallest variation around the selected Tc value. In this example, point  3544  may be picked that corresponds to Tc of approximately 308 mSec., and Td of 8 Sec. Once these values are selected, the number of times the connection and disconnection of the conjugate and membrane pads are to be repeated is calculated by dividing the flow time by Tc+Td. It should be understood that the algorithm described above for selecting the point on the curves  3400  is an example. Other methods and algorithms may be devised to select the desired parameters. As another two-step procedure, once the points on the curves  3400  (e.g., the points  3541 - 3544  in  FIG. 35 ) are calculated, another set of calibration experiments with more timing resolution may be performed in a region of the interest around the points  3541 - 3544  to refine the parameters. 
     The more points are chosen for generating the calibration curves  3400 , the more accurate the results of choosing the appropriate Tc and Td may be. In the example of  FIGS. 34-35 , 56 points were used to demonstrate the process. For a better calibration, more points (e.g., and without limitations, hundreds, thousands, etc.) may be used. The calibration curves  3400  may be generated once for each membrane type for each manufacturer of the membrane. Generating the curves  3400  and the corresponding table(s), may not be a time consuming process given that the result are applicable to a very large number of cartridges. 
     The calibration process may be done by either the manufacturer of the membrane paper or the developer of the test cartridge. Once the appropriate parameters are determined for the particular test the cartridge is supposed to be made for, the parameters may be programmed into the NFC chip on the cartridge. In the case of the stand-alone disposable cartridges, these parameters may be programmed into the firmware of the processor/controller embedded in the cartridge. Alternatively, the parameters may be stored on a network device that may be downloaded to a client device. The client device may then transfer the parameters to the processor/controller of the lateral flow assay device prior to the start of a test. 
     If the lateral flow assay device cartridge also includes a flow control mechanism between the wicking pad and the membrane pad (e.g., as shown in  FIGS. 32 and 33 ), the flow control mechanism between the wicking pad and the membrane pad may also have its Tc and Td parameters that may either use the same values as the Tc and Td for the mechanism between the conjugate pad and the membrane or it may use its own independent Tc and Td values. In either case, the calibration curves may be generated in a similar manner as described above where for the case of independent set of Tc, Td for the wicking pad the experiments may be more extensive in that there may be multiple curve sets to generate. 
     In membrane papers used in conventional lateral flow assay strips and cartridges not employing the flow control techniques described herein, the flow rate of the solution on the membrane paper varies with time and gets slower as the solution front moves away from the beginning strip with time. Another technical advantage provided by the lateral flow assay device and cartridges of the embodiments disclosed herein, is that the values of Tc and Td may change for every cycle of connection and disconnection of the pads and not necessarily be the same every cycle. It, therefore, is possible to control the shape of the flow rate curve and, if desired, even equalize it to become close to linear across the length of the membrane. 
     Some of the present embodiments provide a cycle by cycle control of the flow rate of the fluid. A slower flow rate of the fluid over the membrane results in higher sensitivity for the test as a slower flow rate gives the solution fluid more time to bind to, and interact with, the reagents on the test and control lines as the solution fluid passes over the test and control lines which are on a narrow region on the membrane. 
     Since the present embodiments provide cycle by cycle control over connecting and disconnecting of the conjugate pad and the membrane and provide control over setting the values of Tc and Td, the lateral flow assay device may be configured to keep the flow rate at a higher speed until the fluid front reaches close to the test line and then change the Tc and Td values to slow down the flow rate. This results in a faster overall test time without losing sensitivity. The values of Tc and Td to be used for both the beginning of the flow and for slowing the flow rate down when the fluid reaches near the test line may be determined from calibration curves similar to the calibration curves shown in  FIGS. 34-35  once those curves are generated for the particular membrane material used in the test as was explained above. Since the distance of the test line from the beginning of the membrane and the rate set for the beginning phase of the flow is known, the time it takes for the fluid front to get to a predetermined distance from the test line may be calculated. The processor/controller  505  controlling the lateral flow assay device may keep track of the time and may switch the flow to the slower rate at the right time (e.g., after a time period required for the fluid to reach the predetermined distance from the test line). The cycle by cycle control over connecting and disconnecting of the conjugate pad and the membrane may be applied to any of the embodiments described herein with reference to  FIGS. 32-33 and 36-46 . 
     Some of the present embodiments may compensate for the membrane manufacturing variabilities. One of the factors in manufacturing the membranes is the variability of the flow rate of the membrane from lot to lot. Using the flow control technology of the present embodiments, the flow rate may be set at a point slightly beyond where increase in the sensitivity (e.g., making the flow rate of the fluid over the membrane slower to give the solution fluid more time to bind) is saturated and the material variability may have very minimal to no effect if the flow rate is made slower. In this way, the test cartridge product may have a smaller percent coefficient of variability (CV %). Where to set the optimum flow rate depends on the membrane material selected and the test itself. For each test type and for a given membrane material, some embodiments generate the set of calibration curves and/or tables similar to what was described above with reference to  FIGS. 34-35 . Using these curves and/or tables, a set of experiments are conducted where the flow rate for each experiment is set from the calibration curves, the test is performed, and the sensitivity of the test is measured (e.g. by repeating the test for sequentially diluted concentration levels). 
     The flow rate is then set at a lower value and the tests are repeated to measure the sensitivity again. This process is continued until a point is reached where there is no improvements in the sensitivity. The flow rate and the Tc and Td values corresponding to this saturation point are recorded. The final flow rate set for the test is picked from the calibration curves at a point slightly lower than this flow rate. This ensures that any variations in manufacturing the selected membrane material does not affect the sensitivity of the test as the selected flow rate is always above the point where maximum gain in sensitivity is achieved. The process above may be done once during the manufacturing of a given test type and the Tc and Td parameters are then fixed for volume production for this particular test type and the membrane material selected. The technique of compensating for the membrane manufacturing variabilities may be applied to any of the embodiments described herein with reference to  FIGS. 32-33 and 36-46 . 
     Some embodiments compensate for the viscosity variations of the sample fluid. The flow rate of the membrane is also dependent on the viscosity of the sample fluid. Instead of changing the membrane material for different sample fluids, some embodiments keep the material the same and use the flow control technology described herein to determine parameters for on-off cycling (pulsing) of the conjugate pad and/or the wicking pad to compensate for the viscosity dependence. The optimum values of Tc and Td for a given viscosity are determined by a similar approach described above in generating the calibration curves for a given membrane and experimentally finding the optimum sensitivity for the test type. These parameters may be loaded into the NFC tag of the cartridge and when the processor/controller  505  reads the NFC, the processor/controller  505  sets up the correct parameters automatically. The technique of compensating for the viscosity variations may be applied to any of the embodiments described herein with reference to  FIGS. 32-33 and 36-46 . 
     With further reference to  FIGS. 32 and 33 , the processor  505  may activate and deactivate the solenoid  3251  as described above until the number of connection and disconnection of the pads required to achieve the flow time is achieved. The processor may then stop pulsing the solenoid  3251  and may leave the solenoid  3251  at either engaged or disengaged position depending on what the test specifies. 
     With continued reference to  FIGS. 32 and 33 , a gap  3292  may be initially maintained between the membrane  115  and the wicking pad  120 . Unlike the conventional flow lateral assay cartridges and systems, the membrane  115  is not touching the wicking pad  120 . The membrane  115  may be held away from the wicking pad  120  by the spring  3242  that is attached to the backing  3213  of the wicking pad  120 . The wicking pad  120 , the backing  3213 , and the spring  3242  may be connected to the housing  3230  by a pin or screw  3293 . The spring  3242  may be anchored to the housing  3230  by a pin or screw  3294 . 
     The solenoid  3252  may be used to attach and detach the wicking pad  120  to the membrane  115  by a similar technique as described above with reference to the solenoid  3251 . The processor  505  may start pulsing the solenoid  3252  either at the same time as the solenoid  3251  or once the pulsing of the solenoid  3251  is completed. The latter approach may use less power. 
     The attaching and detaching of the wicking pad  120  and the membrane  115  by the solenoid  3252  and the solenoid shaft  3222  may continue for a certain number of connection and disconnection (which may be determined based on the desired flow rate as described above) after the pulsing of solenoid  3251  is completed at which time the result of the test may be ready for viewing through the clear cover  3205  and/or for reading via sensors such as, for example and without limitations, optical sensors. 
     Some lateral flow assay based tests may not need a wicking pad. The embodiments of the lateral flow assay device  3200  that are used for these test may not include the wicking pad  120  and the solenoid  3252 . For some other tests, the wicking pad  120  may always be left connected to the membrane. The embodiments of the lateral flow assay device  3200  that are used for these tests may not include the solenoid  3252 . In cartridges where both the conjugation pad  110  and the wicking pad  120  have the spring mechanism as discussed above, the solenoid  3252  may always be activated and kept in a position to always attach the wicking pad  120  to the membrane  115  for the entire duration of the test if that is what is desired and specified for the test (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.). 
     As shown in  FIGS. 32 and 33 , the springs  3241  and  3242  do not continue all the way to the tip  3296  of the conjugation pad and the tip  3297  of the wicking pad. There is a small portion of the pads  110  and  120  at the tips  3296  or  3297  that comes in contact with the membrane  115  when the spring  3241  or  3242  is pushed by the corresponding solenoid shaft  3251  or  3252 . With further reference to  FIGS. 32 and 33 , the position of the solenoid shafts  3221  and  3222  on the springs  3241  and  3242  is at a point away from the tips  3296  and  3297 . This is to avoid putting direct pressure on the contact area between the pads from the solenoid shaft and spring which may possibly affect the fluid flow and restrict the flow to some extent. 
     The transistors  3321  and  3322  may perform current amplification to drive the solenoids  3251  and  3252 , respectively. The transistors  3321  and  3322  may be included in the lateral flow assay devices  3200  with a processor  505  that cannot supply enough current on the output pins to drive the solenoids  3251  and  3252 . The embodiments with a processor  505  that provides sufficient current on its output pins to drive the solenoid  3251  and  3252 , may not include the transistors  3321  and  3322 . The resistors  3311  and  3312  that are connected between an output pin of the microcontroller and the base connection of the corresponding transistor  3321  and  3322  are for setting the desired current and may be variable resistors that are adjusted at the manufacturing, depending on the current needed to drive the solenoid. 
     The amount of pressure the conjugate pad  110  may apply on the membrane  115  may be controlled by configuring the amount of pressure that the solenoid shaft  3221  may apply on the spring  3241  and the strength of the spring  3241 . The amount of pressure the wicking pad  120  may apply on the membrane  115  may be controlled by configuring the amount of pressure that the solenoid shaft  3222  may apply on the spring  3242  and the strength of the spring  3242 . 
     Instead of the solenoids  3351  and  3352 , some embodiments may use other actuation mechanisms such as, for example and without limitation, servo motors to push (and pull) the springs  3241  and  3242 . The servo motor may operate in a similar way as described above with reference to the electric motor  530   FIG. 5 . For example, the servo motor may include a rotor (such as the rotor  570  of  FIG. 5 ) that may rotate and cause a rotating shaft (such as the rotating shaft  580  of  FIG. 5 ) to rotate. The rotational movement of the rotating shaft may be converted to linear movement of a linear moving shaft (such as the linear moving shaft  540  of  FIG. 5 ) by a rotational to linear movement converter (such as the rotational to linear movement converter  535  of  FIG. 5  or the shafts  3221 / 3222  of  FIGS. 32-33 ). The rotational to linear movement converter may be a set of one or more screws, a wheel and axle, and/or a set of one or more cams that receive a rotational movement from the rotating shaft and move the linear moving shaft in a straight line. 
     The use of servo motors may eliminate the need for the driver transistors  3321  and  3322  as the servo motors inputs may be directly connected to the processor  505  and may not need high currents. The use of servo motors may lead to a more power efficient design. One advantage of using the servo motor is that, unlike the solenoid, the position of the spring, and hence the proximity of the overlap area of the conjugate pad  110  and membrane  115 , may be accurately controlled, which in turn may result in having more control in the flow time and flow rate. 
     The cartridge shown in  FIGS. 32-33  is for use with a lateral flow assay device that integrates components such as the solenoids, processor, drive transistors, UI (e.g., a keyboard, a display, and/or a touch display), NFC reader, battery, and other switches, connectors, and components. 
     In another embodiment, all the actuation mechanisms and electronics plus a battery may be integrated inside the cartridge providing a completely standalone and disposable cartridge. Small servo motors may be used to actuate the springs. Since the cartridge is standalone and for one-time use, the battery may be small and does not have to be rechargeable. The use of standalone cartridge provides the convenience of not having an external device, but it adds to the cost of the cartridge. In another embodiment of the standalone cartridge, entirely mechanical timers may be used to eliminate the need for the battery, servo motor, and processor/controller (or other electronic circuits) in the disposable cartridge. 
       FIGS. 32-33  illustrate an example of a specific arrangement of the pads  110 ,  115 ,  120  as well as the mechanisms to connection and disconnect the pads. It should be understood that other arrangements may be used for connecting and disconnecting the pads. For example, the entire system shown in  FIG. 32-33  may designed to be flipped vertically, in which case the actuators working on the springs may operate from the top. Examples of this type of arrangements are described below with reference to  FIGS. 43-46 . 
     As another example, electromagnets may be used instead of the solenoids  3251  and/or  3252  and the springs  3241  and  3242  may be made from magnetic material. It should be noted that substances that are attracted by a magnet are called magnetic material or magnetic substances. Examples of the magnetic material include, for example, and without limitations, iron, cobalt, nickel, etc. Substances that are not attracted by a magnet are called non-magnetic materials. Magnetic materials do not have magnetic fields around them, but they are attracted by magnetic fields. Magnets, on the other hand, have magnetic fields around them and can attract and repel other magnets. A magnet can attract magnetic materials but cannot repel them. 
     The electromagnet may be located adjacent to the cartridge&#39;s housing  3230  (e.g., as close as possible to the housing or touching it). When the electromagnet is activated, the magnetic field generated by the electromagnet may pull the corresponding spring towards the electromagnet. When the electromagnet is deactivated, the corresponding spring is released. In order not to consume power when the gap between the pads is open, the preferred direction would be for the conjugate pad  110  to be on top of the membrane  115  (either moving the membrane of  FIG. 32  to the floor of the cartridge housing or vertically flipping the entire system in  FIG. 32 ) such that when the electromagnet is activated and the spring is pulled towards the electromagnet, the conjugate pad  110  may come in contact with the membrane  115 . In the standalone disposable version of the cartridge, the electromagnet may be included inside the cartridge. 
     In another embodiment of the electromagnet-based implementation, the spring may have a post made from a magnetic material that is permanently attached to it and goes through the cartridge housing via a hole on the housing wall and sits flush with the surface of the housing. The electromagnet then interacts with this post. As another example, the spring may have a built-in hook attached to it (e.g., as shown in  FIG. 9 ) that is pulled with a shaft that is controlled and moved via a servo, an electromagnet, a solenoid, or linear actuator. The examples described above with reference to  FIG. 5-7  may be used to move the pads to connect to and disconnect from each other. 
     As described above with reference to  FIGS. 32 and 33 , electromagnets may be used instead of the solenoids  3251  and/or  3252 , and the springs  3241  and  3242  may be made from magnetic material. In some of these embodiments, only a portion (e.g., the tip) of the springs  3241  and  3242  may be made of magnetic material and the rest of the springs  3241  and  3242  may be made of non-magnetic material. In other embodiments, small pieces of magnetic material may be attached to the tips of the springs  3241  and  3242 . 
       FIG. 36  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  3600  that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a spring mechanism and an electromagnet, according to various aspects of the present disclosure.  FIG. 37  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 36 , according to various aspects of the present disclosure. With reference to the lateral flow assay device  3600  of  FIGS. 36 and 37 , the tip of the spring  3241  may be made of magnetic material  3661  and the tip of the spring  3242  may be made of magnetic material  3662 . The rest of the springs  3241  and  3242  may be made of non-magnetic material. Alternatively, a piece of magnetic material  3661  may be attached (e.g., by glue or other appropriate material) to the tip of the spring  3241  and a piece of magnetic material  3662  may be attached to the tip of the spring  3242 . 
     With further reference to  FIG. 36 , the lateral flow assay device  3600  may include the electromagnets  3648  and  3649  instead of the solenoids  3251 - 3252  and the solenoid shafts  3221 - 3222  of  FIG. 32 . Other components of  FIG. 36  may be similar to the corresponding components of  FIG. 32 , which were described above. The electromagnets  3648 - 3649  may be located adjacent to the cartridge&#39;s housing  3230  (e.g., as close as possible to the housing or touching it) without a need to make a hole in the housing (as was needed for the solenoid shafts  3221 - 3222  of  FIG. 32 ). 
     Similar to the lateral flow assay device  3200  of  FIGS. 32 and 33 , in the lateral flow assay device  3600 , the flow rate for the membrane pad  115  and the flow time (which is the time it takes for the solution to travel from one end of the membrane to the other) may be controlled by on-off cycling (pulsing) of the mechanism that brings the conjugate pad  110  and the membrane pad  115  together. The flow time may be controlled with the time that the conjugate  110  and the membrane  115  pads are connected (Tc) and the time that the pads are disconnected (Td). The value of these parameters and the number of times the pads are connected and disconnected may be determined via an algorithm that uses calibration tables or calibration curves as described above with reference to  FIGS. 34 and 35 . 
     If the lateral flow assay device cartridge also includes a flow control mechanism between the wicking pad and the membrane pad (e.g., as shown in  FIGS. 36 and 37 ), the flow control mechanism between the wicking pad and the membrane pad may also have its Tc and Td parameters that may either use the same values as the Tc and Td for the mechanism between the conjugate pad and the membrane or it may use its own independent Tc and Td values, as described above. 
     As shown in  FIGS. 36 and 37 , the electromagnet  3648  may initially (e.g., before the start of a test) be deactivated and a gap  3291  may be maintained between the conjugate pad  110  and the membrane  115 . Similarly, a gap  3292  may initially be maintained between the membrane  115  and the wicking pad  120  in some embodiments. The gaps  3291  and  3292  may be substantially filled by air. The conjugate pad  110  may be held away from the membrane  115  by the spring  3241  (and by the weight of the magnetic material  3661 ) that is attached to the clear backing  3211  of the conjugation pad  110 . When the electromagnet  3648  is activated, the magnetic field generated by the electromagnet  3648  may pull the magnetic material  3661  and the spring  3241  towards the electromagnet  3648  resulting in closing the gap  3291  between the conjugate pad  110  and the membrane  115  and causing the conjugate pad  110  to touch the membrane  115 . 
     For the embodiments that include a wicking pad (such as the embodiment of  FIGS. 36-37 ), when the electromagnet  3649  is deactivated, the wicking pad  120  may be held away from the membrane  115  by the spring  3242  (and by the weight of the magnetic material  3662 ) that is attached to the clear backing  3213  of the wicking pad  120  to maintain the gap  3292 . When the electromagnet  3649  is activated, the magnetic field generated by the electromagnet  3649  may pull the magnetic material  3662  and the spring  3242  towards the electromagnet  3649  resulting in the gap  3292  between the wicking pad  120  and the membrane  115  to be removed and the wicking pad  120  and the membrane  115  to make contact. 
     With further reference to  FIGS. 36 and 37 , the activation and deactivation of the electromagnets  3648  and  3649  may be controlled in order to control the flow the fluid material from the conjugate pad  110  to the membrane  115  and from the membrane  115  to the wicking pad  120 , respectively. Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the electromagnet  3648  may be activated by a command from the processor/controller  505  ( FIG. 37 ), which may cause the electromagnet  3648  to pull the magnetic material  3661  and the spring  3241  such that the conjugate pad  110  to make contact with the membrane  115  to allow the flow of the fluid material from the conjugate pad  110  to the membrane  115 . The electromagnet  3648  may be deactivated by a command from the processor/controller  505 , which may cause the magnetic material  3661  and the spring  3241  to be released, resulting in the gap  3291  to be maintained between the conjugate pad  110  and the membrane  115 . The electromagnet  3648  may include an electromagnetically inductive coil  3691  that is wrapped around a metallic core (or ferrite core)  3651 . The direction of the magnetic field of the coil  3691  may change by the direction of the current through the coil  3691 . Furthermore, when the electric current is turned off, the coil  3691  may no longer generate a magnetic field. 
     Similarly, when the electromagnet  3649  is activated by a command from the processor/controller  505  ( FIG. 37 ), the electromagnet  3649  may pull the magnetic material  3662  and the spring  3242  which may cause the wicking pad  120  to make contact with the membrane  115  to allow the flow of the fluid material from the membrane  115  to the wicking pad  120 . The electromagnet  3649  may be deactivated by a command from the processor/controller  505  that causes the magnetic material  3662  and the spring  3242  to be released, resulting in the gap  3292  to be maintained between the conjugate pad  110  and the membrane  115 . The electromagnet  3649  may include an electromagnetically inductive coil  3692  that is wrapped around a metallic core (or ferrite core)  3652 . The direction of the magnetic field of the coil  3692  may change by the direction of the current through the coil  3692 . Furthermore, when the electric current is turned off, the coil  3692  no longer generates a magnetic field. 
     The transistors  3321  and  3322  may perform current amplification to drive the electromagnets  3648  and  3649 , respectively. The transistors  3321  and  3322  may be included in the lateral flow assay devices  3600  with a processor  505  that cannot supply enough current on the output pins to drive the electromagnets  3648  and  3649 . The embodiments with a processor  505  that provides sufficient current on its output pins to drive the electromagnets  3648  and  3649 , may not include the transistors  3321  and  3322 . The resistors  3311  and  3312  that are connected between an output pin of the processor/controller  505  and the base connection of the corresponding transistor  3321  and  3322  are for setting the desired current and may be variable resistors that are adjusted at the manufacturing, depending on the current needed to drive the solenoid. 
     The amount of pressure the conjugate pad  110  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3648  may generate, the strength of the magnetic material  3661 , and the strength of the spring  3241 . The amount of pressure the wicking pad  120  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3649  may generate, the strength of the magnetic material  3662 , and the strength of the spring  3242 . 
     Some embodiments may use a piezoelectric actuator instead of the solenoids  3251 - 3252  of  FIGS. 32-33  or the electromagnets  3648 - 3649  of  FIGS. 36-37  to control the gaps  3291 - 3292 . A piezoelectric actuator converts an electrical signal into a controlled displacement, referred to as stroke. A piezoelectric stack actuator is made by stacking piezoelectric ceramic discs and metal electrode foils. Applying a voltage to the piezoelectric stack, may result in a controlled displacement of the stack. If the displacement is prevented, a force, referred to as blocking force, may develop. 
     A piezoelectric stack, depending on the type, may require a voltage of between 100 volts to 1000 volts to operate. The precise displacement control of the piezoelectric stack actuators may be used in some of the present embodiments to move a shaft to control the gap between the conjugate pad and membrane and to move another shaft to control the gap between the wicking pad and the membrane. 
       FIG. 38  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  3800  that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a piezoelectric actuator, according to various aspects of the present disclosure. With reference to  FIG. 38 , the lateral flow assay device  3800  may include the piezoelectric actuator stack  3831  to control the gap  3291  between the conjugate pad  110  and the membrane  115 . 
     The piezoelectric actuator, in the example of  FIG. 38  is a piezoelectric stack actuator  3831  that may be made of several individual piezoelectric actuators  3830  that are factory made to be connected to each other. Other embodiments may use other types of piezoelectric actuators. The piezoelectric actuator stack  3831  may be connected to the shaft  3851 . 
     The piezoelectric stack actuator  3831  may be controlled by the processor/controller  505  through the piezoelectric driver  3821 . The piezoelectric driver  3821  may receive one or more signals from the processor/controller  505  and may generate the voltages required for activating and deactivating the piezoelectric stack actuator  3831 . 
     If the lateral flow assay device cartridge also includes a flow control mechanism between the wicking pad and the membrane pad (e.g., as shown in  FIG. 38 ), the lateral flow assay device  3800  may include the piezoelectric actuator stack  3832  to control the gap  3292  between the wicking pad  120  and the membrane  115 . The piezoelectric actuator stack  3832  may be connected to the shaft  3852 . The piezoelectric stack actuator  3832  may be controlled by the processor/controller  505  through the piezoelectric driver  3822 . The piezoelectric driver  3822  may receive one or more signals from the processor/controller  505  and may generate the voltages required for activating and deactivating the piezoelectric stack actuator  3832 . Other components of the lateral flow assay device of  FIG. 38  may be similar to the corresponding components of the lateral flow assay device  3200  of  FIGS. 32-33 . 
       FIG. 38  as shown, includes two operational steps  3801  and  3802 . As shown in step  3801 , a gap  3291  may initially (e.g., at the start of a test) be maintained between the conjugate pad  110  and the membrane  115  by the spring  3241 . A gap  3292  may also initially be maintained between the membrane  115  and the wicking pad by the spring  3242 . The gaps  3291  and  3292  may be substantially filled by air. 
     The processor/controller  505 , in some embodiments, may send one or more signals prior to, or at the start of a test, to the piezoelectric driver  3821  to deactivate the piezoelectric stack actuator  3831 . For example, the piezoelectric driver  3821  may turn off the voltage to the piezoelectric stack actuator  3831 . As shown, the length of the piezoelectric stack actuator  3831  in step  3801  is d1 and the shaft  3851  is not in contact with the spring  3241 . 
     The processor/controller  505 , in some embodiments, may also send one or more signals to the piezoelectric driver  3822  to deactivate the piezoelectric stack actuator  3832 . For example, the piezoelectric driver  3822  may turn off the voltage to the piezoelectric stack actuator  3832 . As shown, the shaft  3852  is not in contact with the spring  3242 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller  505  may send one or more signals, in step  3802 , to the piezoelectric driver  3821  to activate the piezoelectric stack actuator  3831 . The piezoelectric driver  3821  may turn on the voltage to the piezoelectric stack actuator  3831 . 
     As shown in step  3802 , the length of the piezoelectric stack actuator  3831  may expand to d2, generating a stroke of d2-d1. Assuming that the piezoelectric stack actuator  3831  may equally expand in two opposite directions, the edge  3880 , which is closer to the housing  3230  may move at a distance of (d2-d1)/2 towards the housing  3230 , causing the shaft  3851  to move by the same distance of (d2-d1)/2. The lateral flow assay device  3800  may be configured such that the movement of the shaft  3851  by the distance (d2-d1)/2 may cause the gap  3291  to be removed and the conjugate pad  110  may come in contact with the membrane  115 . Once the conjugate pad  110  and the membrane  115  come in full contact, any further displacement of the piezoelectric stack actuator  3831  may be prevented and may be automatically converted to a blocking force. 
     The piezoelectric stack actuator  3831  may be repeatedly activated and deactivated to push the shaft  3851  against the spring  3241  to bring the conjugate pad  110  and the membrane  115  in touch with each other, followed by pulling the shaft  3851  away from the spring  3241  to cause the spring  3241  to separate the conjugate pad  110  from the membrane  115 . Repeatedly connecting and disconnecting the conjugate pad  110  and the membrane  115  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 , as described above with reference to  FIGS. 32-33 . The piezoelectric stack actuator  3832  may be similarly controlled to open and close the gap  3292  between the wicking pad  120  and the membrane  115 . 
     Some embodiments do not use springs in order to open and close the gaps between the conjugate pad and the membrane or between the wicking pad and membrane. Some of these embodiments may connect a magnet to the backing of the conjugate pad and/or to the backing of the wicking pad.  FIG. 39  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  3900  that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by magnets and electromagnets, according to various aspects of the present disclosure.  FIG. 40  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 39 , according to various aspects of the present disclosure. 
     With reference to  FIGS. 39 and 40 , the conjugate pad  110  may be connected to the backing  3211  and the wicking pad  120  may be connected to the backing  3213 . Unlike the lateral flow assay devices of  FIGS. 32-33 and 36-38 , the lateral flow assay device  3900  of  FIGS. 39  and  40  do not include the springs  3241  and  3242  to pull down the conjugate pad  110  and the wicking pad  120 , respectively. 
     The lateral flow assay device  3900  may include a magnet  3971  connected to the backing  3211  and/or a magnet  3972  connected to the backing  3213 . The electromagnets  3648 - 3649 , the coils  3691 - 36392 , and the cores  3651 - 3652 , may be similar to the corresponding components of  FIG. 37 . 
     Similar to the lateral flow assay device  3200  of  FIGS. 32 and 33 , in the lateral flow assay device  3900 , the flow rate for the membrane pad  115  and the flow time (which is the time it takes for the solution to travel from one end of the membrane to the other) may be controlled by on-off cycling (pulsing) of the mechanism that brings the conjugate pad and the membrane pad together. The flow time may be controlled with the time that the conjugate  110  and the membrane  115  pads are connected (Tc) and the time that the pads are disconnected (Td). The value of these parameters and the number of times the pads are connected and disconnected may be determined via an algorithm that uses calibration tables or calibration curves as described above with reference to  FIGS. 34 and 35 . 
     If the lateral flow assay device cartridge also includes a flow control mechanism between the wicking pad and the membrane pad (e.g., as shown in  FIGS. 39 and 40 ), the flow control mechanism between the wicking pad and the membrane pad may also have its Tc and Td parameters that may either use the same values as the Tc and Td for the mechanism between the conjugate pad and the membrane or it may use its own independent Tc and Td values, as described above. 
     The activation and deactivation of the electromagnets  3648  and  3649  may be controlled in order to control the flow of the fluid material from the conjugate pad  110  to the membrane  115  and from the membrane  115  to the wicking pad  120 , respectively. Initially (e.g., before the start of a test), the direction of current in the wire  3360  ( FIG. 40 ) may be set by the processor/controller  505  such that the electromagnet  3648  may pull on the magnet  3971  to maintain the gap  3291  between the conjugate pad  110  and the membrane  115 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller  505  may change the direction of current in the wire  3360 , such that the electromagnet  3648  may repel the magnet  3971  to make the conjugate pad  110  contact the membrane  115  to allow the flow of the fluid material from the conjugate pad  110  to the membrane  115 . 
     Similarly, the direction of current in the wire  4061  ( FIG. 40 ) may be set by the processor/controller  505  such that the electromagnet  3649  may pull on the magnet  3972  to maintain the gap  3292  between the wicking pad  120  and the membrane  115 . In order to close the gap  3292 , the processor/controller  505  may change the direction of current in the wire  4061 , such that the electromagnet  3649  may repel the magnet  3972  to make the wicking pad  120  contact the membrane  115  to allow the flow of the fluid material from the membrane  115  to the wicking pad  120 . 
     The amount of pressure the conjugate pad  110  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3648  may generate and the strength of the magnet  3971 . The amount of pressure the wicking pad  120  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3649  may generates and the strength of the magnet  3972 . 
     In alternative embodiments, the lateral flow assay device may be configured such that the weight of the magnets  3971  and  3972  may pull down the conjugate pad under the force of gravity to maintain the gaps  3291  and  3292 , respectively. In these embodiments, the polarities of the electromagnet  3648  and the magnet  3971  may be configured such that processor/controller may activate the electromagnet  3648  to repel the magnet  3971  in order to close the gap  3291  and bring the conjugate pad  110  in contact with the membrane  115 . Similarly, the polarities of the electromagnet  3649  and the magnet  3972  may be configured such that processor/controller may activate the electromagnet  3649  to repel the magnet  3972  in order to close the gap  3292  and bring the wicking pad  120  in contact with the membrane  115 . 
       FIG. 41  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  4100  that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by magnets and electromagnets that are positioned over the lateral flow assay device&#39;s housing, according to various aspects of the present disclosure.  FIG. 42  is a functional block diagram illustrating one example embodiment of the lateral flow assay device of  FIG. 41 , according to various aspects of the present disclosure. 
     With reference to  FIGS. 41-42 , the electromagnets  3648  and  3649  are positioned over the housing  3230 . Other components of  FIGS. 41-42  are similar to the corresponding components of  FIGS. 39-40 . With further reference to  FIG. 41-42 , initially (e.g., before the start of a test), the direction of current in the wire  3360  ( FIG. 42 ) may be set by the processor/controller  505  such that the electromagnet  3648  may repel (i.e., push on) the magnet  3971  to maintain the gap  3291  between the conjugate pad  110  and the membrane  115 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller  505  may change the direction of current in the wire  3360 , such that the electromagnet  3648  may attract the magnet  3971  to make the conjugate pad  110  contact the membrane  115  to allow the flow of the fluid material from the conjugate pad  110  to the membrane  115 . 
     Similarly, the direction of current in the wire  4061  ( FIG. 42 ) may be set by the processor/controller  505  such that the electromagnet  3649  may repel the magnet  3972  to maintain the gap  3292  between the wicking pad  120  and the membrane  115 . In order to close the gap  3292 , the processor/controller  505  may change the direction of current in the wire  4061 , such that the electromagnet  3649  may attract the magnet  3972  to make the wicking pad  120  contact the membrane  115  to allow the flow of the fluid material from the membrane  115  to the wicking pad  120 . 
     In alternative embodiments, the lateral flow assay device  4100  may be configured such that the weight of the magnets  3971  and  3972  may pull down the conjugate pad under the force of gravity to maintain the gaps  3291  and  3292 , respectively. In these embodiments, the polarities of the electromagnet  3648  and the magnet  3971  may be configured such that processor/controller may activate the electromagnet  3648  to attract the magnet  3971  in order to close the gap  3291  and bring the conjugate pad  110  in contact with the membrane  115 . Similarly, the polarities of the electromagnet  3649  and the magnet  3972  may be configured such that processor/controller may activate the electromagnet  3649  to attract the magnet  3972  in order to close the gap  3292  and bring the wicking pad  120  in contact with the membrane  115 . 
     The amount of pressure the conjugate pad  110  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3648  may generate and the strength of the magnet  3971 . The amount of pressure the wicking pad  120  may apply on the membrane  115  may be controlled by configuring the strength of the magnetic field that the electromagnet  3649  may generates and the strength of the magnet  3972 . 
     In all embodiments of  FIGS. 32-33 and 36-42 , the role of the conjugate pad and the membrane in controlling the gap between the two may be switched. The spring mechanisms, the magnets, or the combination of both may be placed on the membrane instead of the conjugate pad. In these embodiments, the conjugate pad is stationary and the membrane may move up and down to control the opening and closing of the gap between the two. 
     Similarly, In all embodiments of  FIGS. 32-33 and 36-42 , the role of the wicking pad and the membrane in controlling the gap between the two may be switched. The spring mechanisms, the magnets, or the combination of both may be placed on the membrane instead of the wicking pad. In this case, the wicking pad is stationary and the membrane may move up and down to control the opening and closing of the gap between the two. 
     Alternatively, a mix of both approaches may be used where one side may have a stationary conjugate pad and a moving membrane while the other side may have a moving wicking pad and a stationary membrane. And yet in another alternative, a mix of both approaches may be used where one side may have a moving conjugate pad and a stationary membrane while the other side may have a stationary wicking pad and a moving membrane. 
       FIG. 43  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  4300  that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by moving a portion of the membrane with a spring mechanism, according to various aspects of the present disclosure. With reference to  FIG. 43 , the lateral flow assay device  4300  is configured such that the conjugate pad  110  and the wicking pad  120  are positioned on the floor (or the bottom side) of the cartridge housing and the membrane  155  is positioned on the side opposite to the floor, facing towards the conjugate pad  110  and the wicking pad  120 . As shown, the membrane  115  may be held in place by several tabs (or poles)  4390 . The tabs  4390  may be narrow poles configured to hold the membrane  115  in place with minimal contact with the surface of the membrane in order not to impede the flow of the liquid over the membrane  115 . The springs  4341  and  4342  may be secured to the housing  3205  by the pins or screws  4351 - 4352 . 
     With further reference to  FIG. 43 , the solenoids  3251  and  3252  may include the solenoid shafts  3221  and  3222 , respectively. The solenoids  3251  and  3252  may be positioned on the top of the housing  3230 . Other components of the lateral flow assay device  4300  may provide similar functionalities as the corresponding components of  FIG. 32 . 
       FIG. 43  as shown, includes two operational steps  4301  and  4302 . As shown in step  4301 , a gap  4391  may initially (e.g., at the start of a test) be maintained between the conjugate pad  110  and the membrane  115  by the spring  4341 . The spring  4341  may be configured such that the spring  4341  holds a portion of the membrane  115  and the clear backing  3212  down towards the conjugate pad  110  without the membrane  115  and the conjugate pad  110  touching each other. As shown in step  4301 , a gap  4391  is maintained between the conjugate pad  110  and the membrane  115 . 
     A gap  4392  may also initially be maintained between the membrane  115  and the wicking pad by the spring  4342 . The spring  4342  may be configured such that the spring  4342  holds a portion of the membrane  115  and the clear backing  3212  down towards the wicking pad  120  without the membrane  115  and the wicking pad  120  touching each other. As shown in step  4301 , a gap  4392  is maintained between the wicking pad  120  and the membrane  115 . The gaps  4391  and  4392  may be substantially filled by air. 
     The lateral flow assay device  4300  may be configured such that in step  4301  the solenoid shaft  3221  of the solenoid  3251  is kept away from the spring  4311 . For example, the power to the solenoid  3251  may be turned off and/or the lateral flow assay device&#39;s processor/controller (not shown for simplicity) may send one or more signals prior to, or at the start of a test, to the solenoid  3251  to keep the shaft  3221  away from the spring  4341 . 
     The lateral flow assay device  4300  may be configured such that in step  4301  the solenoid shaft  3222  of the solenoid  3252  is kept away from the spring  4312 . For example, the power to the solenoid  3252  may be turned off and/or the lateral flow assay device&#39;s processor/controller may send one or more signals prior to, or at the start of a test, to the solenoid  3252  to keep the shaft  3222  away from the spring  4342 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller may send one or more signals, in step  4302 , to the solenoid  3251  to move the shaft  3221  to push the spring  4341  towards the conjugate pad  110 . As shown in step  4302 , the solenoid shaft  3221  may cause the gap  4391  to be removed and the membrane  115  may come in contact with the conjugate pad  110 . 
     The solenoid shaft  3221  may be repeatedly moved down to push against the spring  4341  to bring the membrane  115  and the conjugate pad  110  in touch with each other, followed by pulling the shaft  3221  away from the spring  4341  to cause the spring  4341  to separate the membrane  115  from the conjugate pad  110 . Repeatedly connecting and disconnecting the membrane  115  and the conjugate pad  110  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 , as described above with reference to  FIGS. 32-33 . A similar process may be used to control the gap  4392  between the membrane  115  and the wicking pad  120  by repeatedly moving the shaft  3222  up and down. 
     The amount of pressure the membrane  115  may apply on the conjugate pad  110  may be controlled by configuring the amount of pressure that the shaft  3221  may apply on the spring  4341  and the strength of the spring  4341 . The amount of pressure the membrane  115  may apply on the wicking pad  120  may be controlled by configuring the amount of pressure that the shaft  3222  may apply on the spring  4342  and the strength of the spring  4342 . 
       FIG. 44  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  4400  that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a piezoelectric actuator that moves a portion of the membrane, according to various aspects of the present disclosure. 
     With reference to  FIG. 44 , the lateral flow assay device  4400  is configured such that the conjugate pad  110  and the wicking pad  120  are positioned on the floor (or the bottom side) of the cartridge housing and the membrane  155  is positioned on the opposite side of the floor facing towards the conjugate pad  110  and the wicking pad  120 . As shown, the membrane  115  may be held in place by several tabs (or poles)  4390 , which may be similar to the tabs  4390  of  FIG. 43 . 
     With reference to  FIG. 44 , the lateral flow assay device  4400  may include the piezoelectric actuator stack  3831  to control the gap  4391  between the conjugate pad  110  and the membrane  115 . The piezoelectric actuator may be similar to the piezoelectric stack actuator  3831  of  FIG. 38  and may be controlled by the processor/controller  505  through the piezoelectric driver  3821 , as described above with reference to  FIG. 38 . 
     If the lateral flow assay device cartridge also includes a flow control mechanism between the wicking pad  120  and the membrane pad  115  (e.g., as shown in  FIG. 44 ), the lateral flow assay device  4400  may include the piezoelectric actuator stack  3832  to control the gap  4392  between the wicking pad  120  and the membrane  115 . The piezoelectric actuator stack  3832  may be connected to the shaft  3852 . The piezoelectric stack actuator  3832  may be controlled by the processor/controller  505  through the piezoelectric driver  3822 , as described above with reference to  FIG. 38 . The piezoelectric stack actuators  4332 - 3832  may be positioned on the top of the housing  3230 . Other components of the lateral flow assay device  4400  of  FIG. 44  may be similar to the corresponding components of the lateral flow assay device of  FIGS. 32-33 and 38 . 
       FIG. 44 , as shown, includes two operational steps  4401  and  4402 . As shown in step  4401 , a gap  4391  may initially (e.g., at the start of a test) be maintained between the conjugate pad  110  and the membrane  115  by the spring  4341 . The spring  4341  may be configured such that the spring  4341  holds a portion of the membrane  115  and the clear backing  3212  down towards the conjugate pad  110  without the membrane  115  and the conjugate pad  110  touching each other. As shown in step  4401 , a gap  4391  is maintained between the conjugate pad  110  and the membrane  115 . 
     A gap  4392  may also initially be maintained between the membrane  115  and the wicking pad by the spring  4342 . The spring  4342  may be configured such that the spring  4342  holds a portion of the membrane  115  and the clear backing  3212  down towards the wicking pad  120  without the membrane  115  and the wicking pad  120  touching each other. As shown in step  4401 , a gap  4392  is maintained between the wicking pad  120  and the membrane  115 . The gaps  4391  and  4392  may be substantially filled by air. 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller  505  may send one or more signals, in step  4402 , to the piezoelectric driver  3821  to activate the piezoelectric stack actuator  3831 . The piezoelectric driver  3821  may turn on the voltage to the piezoelectric stack actuator  3831 . 
     As shown in step  4402 , the length of the piezoelectric stack actuator  3831  may expand and may move the shaft  3851  to push the spring  4341  down, as described above with reference to step  3802  of  FIG. 38 . The lateral flow assay device  4400  may be configured such that the movement of the shaft  3851  may cause the gap  4391  to be removed and the membrane  115  may come in contact with the conjugate pad  110 . Once the membrane  115  and the conjugate pad  110  come to full contact, any further displacement of the piezoelectric stack actuator  3831  may be prevented and may be automatically converted to a blocking force. 
     The piezoelectric stack actuator  3831  may be repeatedly activated and deactivated to push the shaft  3851  against the spring  4341  to bring the membrane  115  and the conjugate pad  110  in touch with each other, followed by pulling the shaft  3851  away from the spring  4341  to cause the spring  4341  to separate the membrane  115  from the conjugate pad  110 . Repeatedly connecting and disconnecting the membrane  115  and the conjugate pad  110  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 , as described above with reference to  FIGS. 32-33 . A similar process may be used to control the gap  4392  between the membrane  115  and the wicking pad  120  by repeatedly activating and deactivating the piezoelectric actuator stack  3832 . 
     The amount of pressure the membrane  115  may apply on the conjugate pad  110  may be controlled by configuring the stroke and the blocking force of the piezoelectric stack  3831 , and by configuring the strength of the spring  4341 . The amount of pressure the membrane  115  may apply on the wicking pad  120  may be controlled by configuring the stroke and the blocking force of the piezoelectric stack  3832 , and by configuring the strength of the spring  4342 . 
       FIG. 45  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  4500  that that controls the gap between the conjugate pad and the membrane and/or the gap between the wicking pad and the membrane by a spring mechanism and an electromagnet that moves a portion of the membrane, according to various aspects of the present disclosure. With reference to  FIG. 45 , the lateral flow assay device  4500  is configured such that the conjugate pad  110  and the wicking pad  120  are positioned on the floor (or the bottom side) of the cartridge housing and the membrane  155  is positioned on the opposite side of the floor facing towards the conjugate pad  110  and the wicking pad  120 . As shown, the membrane  115  may be held in place by several tabs (or poles)  4390 , which may be similar to the tabs  4390  of  FIG. 43 . 
     With reference to the lateral flow assay device  4500  of  FIG. 45 , the tip of the spring  4341  may be made of magnetic material  3661  and the tip of the spring  4342  may be made of magnetic material  3662 . The rest of the springs  4341  and  4342  may be made of non-magnetic material. Alternatively, a piece of magnetic material  3661  may be attached (e.g., by glue or other appropriate material) to the tip of the spring  4341  and a piece of magnetic material  3662  may be attached to the tip of the spring  4342 . 
     With further reference to  FIG. 45 , the lateral flow assay device  4500  may include the electromagnets  3648  and  3649 , which may be similar to the electromagnets  3648  and  3649  of  FIG. 36 . Other components of  FIG. 45  may be similar to the corresponding components of  FIGS. 36 and 43 , which were described above. 
       FIG. 45  as shown, includes two operational steps  4501  and  4502 . As shown in step  4501 , a gap  4391  may initially (e.g., at the start of a test) be maintained between the conjugate pad  110  and the membrane  115  by the spring  4341 . The spring  4341  may be configured such that the spring  4341  holds a portion of the membrane  115  and the clear backing  3212  down towards the conjugate pad  110  without the membrane  115  and the conjugate pad  110  touching each other. As shown in step  4501 , a gap  4391  is maintained between the conjugate pad  110  and the membrane  115 . 
     A gap  4392  may also initially be maintained between the membrane  115  and the wicking pad by the spring  4342 . The spring  4342  may be configured such that the spring  4342  holds a portion of the membrane  115  and the clear backing  3212  down towards the wicking pad  120  without the membrane  115  and the wicking pad  120  touching each other. As shown in step  4501 , a gap  4392  is maintained between the wicking pad  120  and the membrane  115 . The gaps  4391  and  4392  may be substantially filled by air. 
     The lateral flow assay device  4500 , in some embodiments, may be configured such that in step  4501  the power to the electromagnet  3648  is turned off and the spring  4341  may be configured such that the spring pushes a portion of the membrane  115  and a portion of the clear backing  3212  such that the gap  4391  is still maintained between the membrane  115  and the conjugate pad  110 . In other embodiments, the direction of current to the electromagnet  3648 , the strength of the magnetic field generated by the electromagnet  3698 , and the strength of the spring  4341  may be configured such that, in step  4501 , the gap  4391  is still maintained between the membrane  115  and the conjugate pad  110 . 
     In the embodiments that control a gap between the wicking pad and the membrane (e.g., the embodiment shown in  FIG. 45 ), the lateral flow assay device  4500  may be configured such that, in step  4501 , the power to the electromagnet  3649  is turned off and the spring  4342  may be configured such that the spring pushes a portion of the membrane  115  and a portion of the clear backing  3212  such that the gap  4392  is still maintained between the membrane  115  and the wicking pad  120 . In other embodiments, the direction of current to the electromagnet  3649 , the strength of the magnetic field generated by the electromagnet  3699 , and the strength of the spring  4342  may be configured such that, in step  4501 , the gap  4392  is still maintained between the membrane  115  and the wicking pad  120 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller (not shown) of the lateral flow device  4500  may send one or more signals, in step  4502 , to the electromagnet  3648  to push the spring  4341  towards the conjugate pad  110 . 
     As shown in step  4502 , the gap  4391  may be removed and the membrane  115  may come in contact with the conjugate pad  110 . The electromagnet  3648  may be repeatedly turned on and off (or the direction of the current in the electromagnet  3648  may repeatedly be changed) to push the spring  4341  to bring the membrane  115  and the conjugate pad  110  in touch with each other, followed by releasing the spring  4341  (or by pulling spring  4341  towards the electromagnet) to cause the spring  4341  to separate the membrane  115  from the conjugate pad  110 . Repeatedly connecting and disconnecting the membrane  115  and the conjugate pad  110  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 , as described above with reference to  FIGS. 32-33 . A similar process may be used to control the gap  4392  between the membrane  115  and the wicking pad  120  by repeatedly turning electromagnet  3649  on and off or by repeatedly changing the direction of the current in the electromagnet  3649 . 
     The amount of pressure the membrane  115  may apply on the conjugate pad  110  may be controlled by configuring the strength of the magnetic field that the electromagnet  3648  may generate, the strength of the magnetic material  3661 , and the strength of the spring  4341 . The amount of pressure the membrane  115  may apply on the wicking pad  120  may be controlled by configuring the strength of the magnetic field that the electromagnet  3649  may generate, the strength of the magnetic material  3662 , and the strength of the spring  4342 . 
       FIG. 46  is a front elevation view of one example embodiment of a portion of a lateral flow assay device  4600  that controls the gap between the conjugate pad and the membrane and/or between the wicking pad and the membrane by a magnet and an electromagnet that moves a portion of the membrane, according to various aspects of the present disclosure. With reference to  FIG. 46 , the lateral flow assay device  4600  may have a similar configuration as the lateral flow assay device  4500  of  FIG. 45 , except that the lateral flow assay device  4600  does not include the springs  4341 - 4342  and instead has the magnets  3971  and  3972  that are connected to the two sides of the clear backing  3212 . 
       FIG. 46  as shown, includes two operational steps  4601  and  4602 . As shown in step  4601 , a gap  4391  may initially (e.g., at the start of a test) be maintained between the conjugate pad  110  and the membrane  115  by the spring  4341 . The lateral flow assay device  4600 , in some embodiments, may be configured such that, in step  4601 , the power to the electromagnet  3648  is turned off, and the spring  4341  may be configured such that the spring pushes a portion of the membrane  115  and a portion of the clear backing  3212  while the gap  4391  is still maintained between the membrane  115  and the conjugate pad  110 . In other embodiments, the direction of current to the electromagnet  3648 , the strength of the magnetic field generated by the electromagnet  3698 , and the strength of the spring  4341  may be configured such that, in step  4601 , the gap  4391  is still maintained between the membrane  115  and the conjugate pad  110 . 
     In the embodiments that control a gap between the wicking pad  120  and the membrane  115  (e.g., the embodiment shown in  FIG. 46 ), the lateral flow assay device  4600  may be configured such that in step  4601  the power to the electromagnet  3649  is turned off and the spring  4342  may be configured such that the spring pushes a portion of the membrane  115  and a portion of the clear backing  3212  while that the gap  4392  is still maintained between the membrane  115  and the wicking pad  120 . In other embodiments, the direction of current to the electromagnet  3649 , the strength of the magnetic field generated by the electromagnet  3649 , and the strength of the spring  4342  may be configured such that, in step  4601 , the gap  4392  is still maintained between the membrane  115  and the wicking pad  120 . 
     Once the specified conjugation time is lapsed (e.g., specified by the NFC chip  590 , received from the UI of the lateral flow assay device, received from an external device, etc.), the processor/controller (not shown) of the lateral flow device  4600  may send one or more signals, in step  4602 , to the electromagnet  3648  to push the magnet  3971  towards the conjugate pad  110 . 
     As shown in step  4602 , the gap  4391  may be removed and the membrane  115  may come in contact with the conjugate pad  110 . The electromagnet  3648  may be repeatedly turned on and off (or the direction of the current in the electromagnet  3648  may repeatedly be changed) to push the magnet  3971  to bring the membrane  115  and the conjugate pad  110  in touch with each other, followed by pulling magnet  3971  towards the electromagnet to separate the membrane  115  from the conjugate pad  110 . Repeatedly connecting and disconnecting the membrane  115  and the conjugate pad  110  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 , as described above with reference to  FIGS. 32-33 . A similar process may be used to control the gap  4392  between the membrane  115  and the wicking pad  120  by repeatedly turning electromagnet  3649  on and off or by repeatedly changing the direction of the current in the electromagnet  3649 . 
     The amount of pressure the membrane  115  may apply on the conjugate pad  110  may be controlled by configuring the strength of the magnetic field that the electromagnet  3648  may generate and the strength of the magnet  3971 . The amount of pressure the membrane  115  may apply on the wicking pad  120  may be controlled by configuring the strength of the magnetic field that the electromagnet  3649  may generate and the strength of the magnet  3972 . 
     As an alternative to the configuration of the conjugate pad  110 , the membrane  115 , and the wicking pad  120  of  FIGS. 43-46 , the lateral flow assay in some embodiments may be configured such that the conjugate pad  110  and the wicking pad to be on top of the membrane  115 , either by moving the membrane to the floor of the cartridge housing or vertically flipping the entire system. For example, in such an alternative configuration for  FIG. 36 , when the electromagnet  3648  is deactivated, the spring  3241  may push down the conjugate pad  110  away from the membrane to maintain the gap  3291 . In these alternative embodiments, the electromagnet  3648  may be placed under the housing  3230 , such that, when the electromagnet  3648  is activated, the magnetic material  3261  and the spring  3241  are pulled down towards the electromagnet  3248  to make the conjugate pad  110  to come in contact with the membrane  115 . 
     Furthermore, in this configuration, the electromagnet  3649  may be placed under the housing  3230 . When the electromagnet  3649  is deactivated, the spring  3242  may push down the wicking pad  120  away from the membrane to maintain the gap  3292 . When the electromagnet  3649  is activated, the magnetic material  3262  and the spring  3242  are pulled down towards the electromagnet  3649  to make the wicking pad  120  to come in contact with the membrane  115 . 
     As another alternative to the embodiments of  FIGS. 43-46 , a mix of two approaches may be used where one side may have a stationary conjugate pad and a moving membrane while the other side may have a moving wicking pad and a stationary membrane. And yet in another alternative, a mix of two approaches may be used where one side may have a moving conjugate pad and a stationary membrane while the other side may have a stationary wicking pad and a moving membrane. 
     With reference to  FIGS. 20-31 , the exemplary embodiments were described with reference to removing the gap between the pads at once. For example,  FIG. 21  was described by moving down the section  2106  of the lateral flow device&#39;s housing to remove the gap  2050 . In other embodiments, the gap  2050  may be repeatedly opened and closed by moving the section  2106  of the housing up and down in order to repeatedly bring the conjugate pad  110  and the membrane  115  in touch with each other and then separate them from each other. Repeatedly connecting and disconnecting the conjugate pad  110  and the membrane  115  provides the technical advantage of controlling the flow of fluid material from the conjugate pad  110  into the membrane  115 . 
     The number of times the moving section  2106  is moved up or down, the duration that the moving section  2106  stays up or down, and the time between the moving up and down actions may control the amount of contact between the conjugate pad  110  and the membrane  115 . The amount of contact between the conjugate pad  110  and the membrane  115  may in turn be used by the processor of the lateral flow assay device to control the flow time (the time would take for the fluid material to travel the length of the membrane  115 , going over the test line  125  and the control line  135  to reach the wicking pad  120 ). 
     With reference to  FIG. 28 , a similar technique may be used to repeatedly move the sections  2806 ,  2807 , and/or  2808  up or down to control the time the fluid material comes in contact with the test line  125 , the time the fluid material comes in contact with the control line  130 , and/or the flow rate across the flow path of the lateral flow assay device. 
     With reference to  FIG. 23 , the pole  2310  was described to moving down to remove the gap  2050 . In other embodiments, the gap  2050  may be repeatedly opened and closed by moving the pole  2310  up and down in order to repeatedly bring the conjugate pad  110  and the membrane  115  in touch with each other and then separate them from each other. Repeatedly connecting and disconnecting the conjugate pad  110  and the membrane  115  may be used to control the flow of fluid material from the conjugate pad  110  into the membrane  115 . 
     With reference to  FIG. 29 , a similar technique may be used to repeatedly move the poles  2310 ,  2911 , and/or  2912  up or down, which provides the technical advantage of controlling the time the fluid material comes in contact with the test line  125 , the time the fluid material comes in contact with the control line  130 , and/or the flow rate across the flow path of the lateral flow assay device. 
     One advantage of using a servo or a linear actuator for moving the shaft that pushes the spring  3241  (and/or  3242 ) is that the position of the shaft  3221  (and/or  3222 ) may be accurately controlled, which in turn results in the technical advantage of being able to control the proximity of the overlap area of the conjugate pad  110  and the membrane  115  (and/or, similarly, the overlap area of the membrane  115  and the wicking pad  120 ). 
     The accurate control over the proximity, which also controls the amount of pressure between the two pads at the overlap area, is another independent parameter in controlling the flow rate and flow time. For the embodiments of the lateral flow assays that use this feature, the set of the calibration tables or calibration curves may be generated for each distinct position of the servo. Without limitations, the distinct positions of the servo shaft may usually be few in practical cases. If a servo or linear actuator is used on both the conjugate pad side as well of the wicking pad side of the device, then there may be two sets of positions for which the calibration tables or curves need to be generated. For example, if the distinct positions of the servo are limited to three positions for each side, there will be nine different combination of the two positions resulting in nine different sets of calibration tables or curves. 
     III. Computer System 
     Some of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer readable storage medium (also referred to as computer readable medium). When these instructions are executed by one or more processing unit(s) (e.g., one or more processors, cores of processors, or other processing units), they cause the processing unit(s) to perform the actions indicated in the instructions. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, RAM chips, hard drives, EPROMs, etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections. 
     In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage, which can be read into memory for processing by a processor. Also, in some embodiments, multiple software inventions can be implemented as sub-parts of a larger program while remaining distinct software inventions. In some embodiments, multiple software inventions can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software invention described here is within the scope of the invention. In some embodiments, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs. 
       FIG. 47  conceptually illustrates an electronic system  4700  with which some embodiments of the invention (e.g., the microprocessors, the microcontrollers, the controller, the client devices described above) are implemented. The electronic system  4700  can be used to execute any of the control, virtualization, or operating system applications described above. The electronic system  4700  may be a computer (e.g., desktop computer, personal computer, tablet computer, server computer, mainframe, blade computer etc.), phone, PDA, or any other sort of electronic device. Such an electronic system includes various types of computer readable media and interfaces for various other types of computer readable media. Electronic system  4700  includes a bus  4705 , processing unit(s)  4710 , a system memory  4720 , a read-only memory (ROM)  4730 , a permanent storage device  4735 , input devices  4740 , and output devices  4745 . 
     The bus  4705  collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of the electronic system  4700 . For instance, the bus  4705  communicatively connects the processing unit(s)  4710  with the read-only memory  4730 , the system memory  4720 , and the permanent storage device  4735 . 
     From these various memory units, the processing unit(s)  4710  retrieve instructions to execute and data to process in order to execute the processes of the invention. The processing unit(s) may be a single processor or a multi-core processor in different embodiments. 
     The read-only-memory  4730  stores static data and instructions that are needed by the processing unit(s)  4710  and other modules of the electronic system. The permanent storage device  4735 , on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when the electronic system  4700  is off. Some embodiments of the invention use a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) as the permanent storage device  4735 . 
     Other embodiments use a removable storage device (such as a floppy disk, flash drive, etc.) as the permanent storage device. Like the permanent storage device  4735 , the system memory  4720  is a read-and-write memory device. However, unlike storage device  4735 , the system memory is a volatile read-and-write memory, such as random access memory. The system memory stores some of the instructions and data that the processor needs at runtime. In some embodiments, the invention&#39;s processes are stored in the system memory  4720 , the permanent storage device  4735 , and/or the read-only memory  4730 . From these various memory units, the processing unit(s)  4710  retrieve instructions to execute and data to process in order to execute the processes of some embodiments. 
     The bus  4705  also connects to the input and output devices  4740  and  4745 . The input devices enable the user to communicate information and select commands to the electronic system. The input devices  4740  include alphanumeric keyboards and pointing devices (also called “cursor control devices”). The output devices  4745  display images generated by the electronic system. The output devices include printers and display devices, such as cathode ray tubes (CRT) or liquid crystal displays (LCD). Some embodiments include devices, such as a touchscreen, that function as both input and output devices. 
     Finally, as shown in  FIG. 47 , bus  4705  also couples electronic system  4700  to a network  4725  through a network adapter (not shown). In this manner, the computer can be a part of a network of computers (such as a local area network (“LAN”), a wide area network (“WAN”), an Intranet, or a network of networks, such as the Internet. Any or all components of electronic system  4700  may be used in conjunction with the invention. 
     Some embodiments include electronic components, such as microprocessors, storage, and memory, that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media). Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM), recordable compact discs (CD-R), rewritable compact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc.), flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.), magnetic and/or solid state hard drives, read-only and recordable Blu-Ray® discs, ultra density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media may store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter. 
     While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some embodiments are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some embodiments, such integrated circuits execute instructions that are stored on the circuit itself. 
     As used in this specification, the terms “computer,” “server,” “processor,” “processing unit,” “controller,” and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms display or displaying means displaying on an electronic device. As used in this specification, the terms “computer readable medium,” “computer readable media,” and “machine readable medium” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral or transitory signals. 
     While the invention has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. In addition, a number of the figures (including  FIGS. 11 and 26 ) conceptually illustrate processes. The specific operations of these processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process. 
     In a first aspect, a lateral flow assay device, comprises: a conjugate pad configured to receive a quantity of fluid; a membrane comprising a test line for determining whether the fluid comprises a target analyte; and a removable physical barrier, wherein, in a first state of the lateral flow assay device, the removable physical barrier is between the conjugate pad and the membrane and prevents the fluid from flowing from the conjugate pad into the membrane, and wherein, in a second state of the lateral flow assay device, the removable physical barrier is removed from between the conjugate pad and the membrane causing the conjugate pad to be connected to the membrane and allowing the fluid to flow from the conjugate pad into the membrane and the test line by capillary action. 
     In an embodiment of the first aspect, the lateral flow assay device further comprises at least a first magnet connected to the removable physical barrier for pulling out the removable physical barrier from between the conjugate pad and the membrane by a second magnet external to the lateral flow assay device. 
     In another embodiment of the first aspect, the conjugate pad contains an antibody for binding to the target analyte, wherein the target analyte and the antibody require a first time period to bind, the lateral flow assay device further comprises at least a first magnet connected to the removable physical barrier; an electromagnet comprising a coil and a core, wherein the core acts as a magnet when a current is passed through the coil, wherein the core does not act as a magnet when no current is passed through the coil, wherein the core is configured to stay at a specific distance from the first magnet at a beginning of an assay test, and wherein the core is configured to attract the first magnet and pull the removable physical barrier from between the conjugate pad and the membrane when the core acts as a magnet and the core is at the specific distance from the first magnet; and a processing unit configured to: disconnect the current from the coil prior to the beginning of the assay test; and after the first time period from the beginning of the assay test, connecting the current to the coil to cause the core to act as a magnet and pull the first magnet and the movable physical barrier from between the conjugate pad and the membrane. 
     In another embodiment of the first aspect, the fluid is transported from the conjugate pad to the membrane by capillary action, and the first time period is greater than a time that takes for the fluid to be transported by capillary action from the sample pad to the conjugate pad and from the conjugate pad to the membrane. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises at least one hole on the removable physical barrier for pulling out the removable physical barrier from between the conjugate pad and the membrane by at least one hook engaged into the at least one hole. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises at least one hole on the removable physical barrier; and at least one string going through the at least one pole for pulling out the removable physical barrier from between the conjugate pad and the membrane by at least one hook engaged into the at least one string. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises at least one grove on the removable physical barrier for pulling out the removable physical barrier from between the conjugate pad and the membrane. 
     In another embodiment of the first aspect, wherein the removable physical barrier is a first removable physical barrier, and wherein the membrane is a first membrane, the lateral flow assay device further comprises: a second membrane comprising a control line for determining whether the lateral flow assay device has successfully analyzed the fluid; and a second removable physical barrier, wherein, in a third state of the lateral flow assay device, the second removable physical barrier is between the first and second membranes and preventing the fluid from flowing from the first membrane and the test line into the second membrane, and wherein, in a fourth state of the lateral flow assay device, the second removable physical barrier is removed from between the first and the second membranes causing the first membrane to be connected to the second membrane and allowing the fluid to flow from the first membrane and the test line into the second membrane and the control line by capillary action. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises: a wicking pad; and a third removable physical barrier, wherein, in a fifth state of the lateral flow assay device, the third removable physical barrier is between the second membrane and the wicking pad and preventing the fluid from flowing from the second membrane and the control line into the wicking pad, and wherein, in a sixth state of the lateral flow assay device, the third removable physical barrier is removed from between the second membrane and the wicking pad causing the second membrane to be connected to the wicking pad and allowing the fluid to flow from the second membrane and the control line into the wicking pad by capillary action. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises a sample pad fluidically connected to the conjugate pad, wherein the sample is configured to receive said quantity of fluid and transport the fluid to the conjugate pad by capillary action. 
     In another embodiment of the first aspect, the lateral flow assay device further comprises a housing comprising a housing bed, where a portion of the conjugate pad and a portion of the membrane are located on the housing bed, wherein the housing bed has a permanent gap, wherein in said first state of the lateral flow assay device, the permanent gap in the housing bed prevents the fluid from leaking from the conjugate pad into the membrane. 
     In a second aspect, a lateral flow assay device, comprises: a sample pad for receiving a quantity of fluid; a conjugate pad fluidically connected to the sample pad, wherein the sample pad is configured to transport the fluid to the conjugate pad by capillary action; and a membrane comprising a test line for determining whether the fluid comprises a target analyte, wherein, in a first state of the lateral flow assay device, the lateral flow assay device is configured with a removable gap between the conjugate pad and the membrane, the removable gap substantially filled with air and preventing the fluid from flowing from the conjugate pad into the membrane, and wherein, in a second state of the lateral flow assay device, the removable gap is removed from between the conjugate pad and the membrane causing the conjugate pad to come in contact with the membrane and allowing the fluid to flow from the conjugate pad into the membrane and the test line by capillary action. 
     In an embodiment of the second aspect, the lateral flow assay device further comprises: a housing covering at least a portion of the conjugate pad and the membrane, wherein the housing comprises a movable section comprising a side attached to at least a portion of the conjugate pad, wherein, in the first state of the lateral flow assay device, the movable section creates the removable gap by keeping the conjugate pad and the membrane separate, and wherein, in the second state of the lateral flow assay device, the movable section pushes the conjugate pad towards the membrane causing the conjugate pad and the membrane to come in contact with each other. 
     In another embodiment of the second aspect, the side of the movable part is attached to the conjugate pad by an adhesive substance. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a set of one or more holes going through the conjugate pad and the membrane; and a set of one or more movable poles, each movable pole going through a hole in the set of holes, wherein, in the first state of the lateral flow assay device, the set of movable poles is connected to the conjugate pad and creates the removable gap by keeping the conjugate pad and the membrane separate, and wherein, in the second state of the lateral flow assay device, the set of one or more movable poles is moved to remove the removable gap and connect the conjugate pad and the membrane. 
     In another embodiment of the second aspect, the set of movable poles is connected to the conjugate pad by an adhesive substance. 
     In another embodiment of the second aspect, wherein the removable gap is a first removable gap, and wherein the membrane is a first membrane, the lateral flow assay device further comprises: a second membrane comprising a control line for determining whether the lateral flow assay device has successfully analyzed the fluid, wherein, in a third state of the lateral flow assay device, the lateral flow assay device is configured with a second removable gap between the first membrane and the second membrane, the second removable gap substantially filled with air and preventing the fluid from flowing from the first membrane and the test line into the second membrane and the control line, and wherein in a fourth state of the lateral flow assay device, the second removable gap is removed from between the first membrane and the second membrane causing the first membrane to be connected to the second membrane and allowing the fluid to flow from the first membrane and the test line into the second membrane and the control line by capillary action. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a housing covering at least a portion of the conjugate pad and the first and second membranes, wherein the housing comprises a movable section comprising a side attached to at least a portion of the second membrane, wherein, in the third state of the lateral flow assay device, the movable section creates the second removable gap by keeping the second membrane and the first membrane separate, and wherein, in the fourth state of the lateral flow assay device, the movable section pushes the second membrane towards the first membrane causing the second membrane and the first membrane to connect to each other. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a set of one or more holes going through the first and second membranes; and a set of one or more movable poles, each movable pole going through a hole in the set of holes, wherein, in the third state of the lateral flow assay device, the set of movable poles is connected to the second membrane and creates the second removable gap by keeping the first and second membranes separate, and wherein, in the fourth state of the lateral flow assay device, the set of one or more movable poles is moved to remove the second removable gap and connect the first and second membranes. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a wicking pad, wherein, in a fifth state of the lateral flow assay device, the lateral flow assay device is configured with a third removable gap between the wicking pad and the second membrane, the third removable gap substantially filled with air and preventing the fluid from flowing from the second membrane and the control line into the wicking pad, and wherein, in a sixth state of the lateral flow assay device, the third gap is removed from between the second membrane and the wicking pad causing the second membrane to be connected to the wicking pad and allowing the fluid to flow from the second membrane and the control line into the wicking pad by capillary action. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a housing covering at least a portion of the second membrane and the wicking pad, wherein the housing comprises a movable section comprising a side attached to at least a portion of the wicking pad, wherein, in the fifth state of the lateral flow assay device, the movable section creates the third removable gap by keeping the wicking pad separate from the second membrane, and wherein, in the sixth state of the lateral flow assay device, the movable section pushes the wicking pad towards the second membrane causing the wicking pad and the second membrane to connect to each other. 
     In another embodiment of the second aspect, the lateral flow assay device further comprises: a set of one or more holes going through the second membrane and the wicking pad; and a set of one or more movable poles, each removable pole going through a hole in the set of holes, wherein, in the fifth state of the lateral flow assay device, the set of movable poles is connected to the wicking pad and creating the third removable gap by keeping the wicking pad and the second membrane separate, and wherein, in the sixth state of the lateral flow assay device, the set of one or more movable poles is moved to remove the third removable gap and connect the wicking pad and the second membrane. 
     In a third aspect, a lateral flow assay device, comprises: a sample pad for receiving a quantity of fluid; a conjugate pad fluidically connected to the sample pad, wherein the sample pad is configured to transport the fluid to the conjugate pad by capillary action, wherein the conjugate pad contains an antibody for binding to the target analyte, and wherein the target analyte and the antibody require a first time period to bind; a membrane comprising a test line for determining whether the fluid comprises a target analyte; a removable physical barrier; at least a first magnet connected to the removable physical barrier; a processing unit; and an electromagnet comprising a coil and a core, wherein the core acts as a magnet when a current is passed through the coil, wherein the core does not act as a magnet when no current is passed through the coil, wherein the core is configured to stay at a specific distance from the first magnet at a beginning of an assay test, and wherein the core is configured to attract the first magnet and pull the removable physical barrier from between the conjugate pad and the membrane when the core acts as a magnet and the core is at the specific distance from the first magnet, wherein the removable physical barrier is configured to stay between the conjugate pad and the membrane at the beginning of the assay test, preventing the fluid from flowing from the conjugate pad into the membrane, wherein the processing unit is configured to: disconnect the current from the coil prior to the beginning of the assay test; and after the first time period from the beginning of the assay test, connecting the current to the coil to cause the core to act as a magnet and pull the first magnet and the movable physical barrier from between the conjugate pad and the membrane, wherein, when the removable physical barrier is pulled from between the conjugate pad and the membrane, the conjugate pad is connected to the membrane, allowing the fluid to flow from the conjugate pad into the membrane and the test line by capillary action. 
     In an embodiment of the third aspect, the first time period is greater than a time that takes for the fluid to be transported by capillary action from the sample pad to the conjugate pad and from the conjugate pad to the membrane. 
     In a fourth aspect, a system for performing an assay test comprises: a lateral flow assay device; an electromagnet; and a processing unit, wherein the lateral flow assay device comprises: a sample pad for receiving a quantity of fluid; a conjugate pad fluidically connected to the sample pad, wherein the sample pad is configured to transport the fluid to the conjugate pad by capillary action, wherein the conjugate pad contains an antibody for binding to the target analyte, and wherein the target analyte and the antibody require a first time period to bind; a membrane comprising a test line for determining whether the fluid comprises a target analyte; a removable physical barrier; and at least a first magnet connected to the removable physical barrier; wherein the electromagnet comprises a coil and a core, wherein the core acts as a magnet when a current is passed through the coil, wherein the core does not act as a magnet when no current is passed through the coil, wherein the core is configured to stay at a specific distance from the first magnet at a beginning of the assay test, and wherein the core is configured to attract the first magnet and pull the removable physical barrier from between the conjugate pad and the membrane when the core acts as a magnet and the core is at the specific distance from the first magnet; wherein the removable physical barrier is configured to stay between the conjugate pad and the membrane at the beginning of the assay test, preventing the fluid from flowing from the conjugate pad into the membrane, wherein the processing unit is configured to: disconnect the current from the coil prior to the beginning of the assay test; and after the first time period from the beginning of the assay test, connecting the current to the coil and causing the core to act as a magnet and pull the first magnet and the movable physical barrier from between the conjugate pad and the membrane, and wherein, when the removable physical barrier is pulled from between the conjugate pad and the membrane, the conjugate pad is connected to the membrane, allowing the fluid to flow from the conjugate pad into the membrane and the test line by capillary action. 
     In an embodiment of the fourth aspect, the first time period is greater than a time that takes for the fluid to be transported by capillary action from the sample pad to the conjugate pad and from the conjugate pad to the membrane. 
     The above description presents the best mode contemplated for carrying out the present embodiments, and of the manner and process of practicing them, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which they pertain to practice these embodiments. The present embodiments are, however, susceptible to modifications and alternate constructions from those discussed above that are fully equivalent. Consequently, the present invention is not limited to the particular embodiments disclosed. On the contrary, the present invention covers all modifications and alternate constructions coming within the spirit and scope of the present disclosure. For example, the steps in the processes described herein need not be performed in the same order as they have been presented and may be performed in any order(s). Further, steps that have been presented as being performed separately may in alternative embodiments be performed concurrently. Likewise, steps that have been presented as being performed concurrently may in alternative embodiments be performed separately.