Abstract:
Methods of preparing assays and of assaying, using substantially self-contained, portable, user-initiated fluidic assay systems. Example assays include diagnostic assays and chemical detection assays. Diagnostic assays may include, without limitation, enzyme-linked immuno-sorbent assays (ELISA), and may include one or more sexually transmitted disease (STD) diagnostic assays. An assay system may include one or more fluid chambers, one or more fluid paths amongst the fluid chambers and/or between the fluid chambers, a sample portion, and/or an assay portion. The assay system may include a fluid controller system to dispense fluid from the one or more fluid chambers, and a user-initiated actuator to control the fluid controller system. The fluid controller system may be configured to dispense fluids serially, and may be configured to mix a plurality of fluids. The user-initiated actuator system may include an external user-operated trigger mechanism. The assay apparatus may include a display window to view assay results.

Description:
BACKGROUND 
       [0001]    Given the great strain on the healthcare work force, the increased prevalence of many common diseases and the substantial delay in treatment caused by remote testing, it has become imperative to develop rapid, easy-to-use automated diagnostic devices and platforms to enable efficient and accurate point-of-care disease detection. 
         [0002]    Historic obstacles to point-of-care devices include manufacturing challenges, ease-of-use limitations, and government regulations. Some of these obstacles have been reduced through advances in technology and recognition by governments and other regulatory bodies of the importance of point-of-care testing. However, important considerations, including ease-of-use and accuracy, still render point-of-care tests unsuitable for many healthcare facilities. 
         [0003]    Conventional point-of-care diagnostic systems utilize capillary action or test strips, which provide limited ability to perform many diagnostic assays, such as fluidic assays. 
         [0004]    Fluidic assays, such as enzyme-linked immuno-sorbent assays (ELISAs), are capable of detecting the presence of many diseases ranging from cancer to diseases like herpes simplex type 2, and generally require relatively few operational steps. However, these steps are typically preformed by trained lab technicians. 
       SUMMARY 
       [0005]    Disclosed herein are methods and systems to perform point-of-care, user-initiated fluidic assays, using substantially self-contained, portable, user-initiated fluidic assay systems. 
         [0006]    Example assays include diagnostic assays and chemical detection assays. Diagnostic assays include, without limitation, enzyme-linked immuno-sorbent assays (ELISA), and may include one or more sexually transmitted disease (STD) diagnostic assays. 
         [0007]    An assay system may include a housing having one or more fluid chambers, a fluid controller system to dispense fluid from the one or more fluid chambers, and a user-initiated actuator to control the fluid controller system. 
         [0008]    The actuator may be configured to serially move fluid controllers from functionally closed positions to functionally open positions, to control fluid flow from the fluid chambers. 
         [0009]    The fluid controller system may be configured to dispense fluids serially, and may be configured to mix a plurality of fluids. 
         [0010]    The housing may include an assay portion and the fluid controller system may be configured to dispense fluids from one or more of the fluid chambers to the assay portion. 
         [0011]    The housing may include one or more fluid paths amongst the fluid chambers and/or to the assay portion, and the fluid controller system may be configured to serially align fluid chamber outlets with corresponding fluid paths. 
         [0012]    The housing may include a sample chamber to receive an assay sample, such as a biological sample, and one or more of the fluid paths may include the sample chamber. 
         [0013]    The user-initiated actuator system may include an external user-operated trigger mechanism to initiate the actuator system. The actuator system may include a mechanical actuator system, and may include a compressible spring actuator system. 
         [0014]    The assay apparatus may include a display window to view assay results. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         [0015]    In the drawings, like reference numbers indicate identical or functionally similar elements. Additionally, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears. 
           [0016]      FIG. 1  is a process flowchart of a method of performing an assay with a substantially self-contained, point-of-care, user-initiated fluidic assay system. 
           [0017]      FIG. 2  is a block diagram of a portable, point-of-care, user-initiated fluidic assay system. 
           [0018]      FIG. 3  is a perspective view of a portable, point-of-care, user-initiated fluidic assay system. 
           [0019]      FIG. 4  is a process flowchart of a method of preparing a portable, point-of-care, user-initiated fluidic assay system. 
           [0020]      FIG. 5  is a process flowchart of a method of using an assay system prepared in accordance with  FIG. 4 . 
           [0021]      FIG. 6  is a cross-sectional block diagram of a pump  600 . 
           [0022]      FIG. 7  is another cross-sectional block diagram of pump  600 . 
           [0023]      FIG. 8  is a cross-sectional block diagram of view A-A of pump  600 . 
           [0024]      FIG. 9  is a cross-sectional block diagram of a multi-chamber pump  900 . 
           [0025]      FIG. 10  is another cross-sectional block diagram of pump  900 . 
           [0026]      FIG. 11  is a cross-sectional block diagram of a pump  1100  configured to serially mix fluids from multiple fluid chambers. 
           [0027]      FIG. 12  is another cross-sectional block diagram of pump  1100 . 
           [0028]      FIG. 13  is another cross-sectional block diagram of pump  1100 . 
           [0029]      FIG. 14  is another cross-sectional block diagram of pump  1100 . 
           [0030]      FIG. 15  is a cross-sectional block diagram of a pump  1500  configured to simultaneously mix fluids from multiple fluid chambers. 
           [0031]      FIG. 16  is another cross-sectional block diagram of pump  1500 . 
           [0032]      FIG. 17  is another cross-sectional block diagram of pump  1500 . 
           [0033]      FIG. 18  is a cross-sectional block diagram of a pump  1800  configured to simultaneously mix fluids from multiple fluid chambers. 
           [0034]      FIG. 19  is another cross-sectional block diagram of pump  1800 . 
           [0035]      FIG. 20  is another cross-sectional block diagram of pump  1800 . 
           [0036]      FIG. 21  is a cross-sectional block diagram of a portion of an assay system  2100 , including a user-initiated actuator. 
           [0037]      FIG. 22  is a cross-sectional perspective view of an assay system  2200 . 
           [0038]      FIG. 23  is a cross-sectional block diagram of assay system  2200 . 
           [0039]      FIG. 24  is another cross-sectional block diagram of assay system  2200 . 
           [0040]      FIG. 25  is another cross-sectional block diagram of assay system  2200 . 
           [0041]      FIG. 26  is another cross-sectional block diagram of assay system  2200 . 
           [0042]      FIG. 27  is another cross-sectional block diagram of assay system  2200 . 
           [0043]      FIG. 28  is a cross-sectional perspective view of an assay system  2800 . 
           [0044]      FIG. 29  is another cross-sectional block diagram of assay system  2800 . 
           [0045]      FIG. 30  is another cross-sectional block diagram of assay system  2800 . 
           [0046]      FIG. 31  is another cross-sectional block diagram of assay system  2800 . 
           [0047]      FIG. 32  is another cross-sectional block diagram of assay system  2800 . 
           [0048]      FIG. 33  is another cross-sectional block diagram of assay system  2800 . 
           [0049]      FIG. 34  is cross-sectional view of a mechanical actuator system  3400 . 
           [0050]      FIG. 35  is another cross-sectional view of mechanical actuator system  3400 . 
           [0051]      FIG. 36  is another cross-sectional view of mechanical actuator system  3400 . 
           [0052]      FIG. 37  is a perspective view of an assay system  3700 . 
           [0053]      FIG. 38  is another perspective view of assay system  3700 . 
           [0054]      FIG. 39  is a cross-sectional diagram of mechanical control rod actuators  3910 . 
           [0055]      FIG. 40  is another cross-sectional diagram of control rod actuators  3910 . 
           [0056]      FIG. 41  is another cross-sectional diagram of control rod actuators  3910 . 
       
    
    
     DETAILED DESCRIPTION 
       [0057]    Disclosed herein are methods of performing point-of-care, user-initiated fluidic assays, and substantially self-contained, portable, point-of-care, user-initiated fluidic assay systems. 
         [0058]    Example methods and systems are described herein with respect to immunoassays, for illustrative purposes. Based on the teachings herein, one skilled in the art will understand that the methods may be implemented with respect to other diagnostic assays and with respect to chemical assays. 
         [0059]    An immunoassay is a biochemical test to detect a substance, or measure a concentration of a substance, in a biological sample such as blood, saliva, or urine, using a reaction between an antibody and an antigen specific to the antibody. 
         [0060]    An immunoassay may be used to detect the presence of an antigen or an antibody. For example, when detecting an infection, the presence of an antibody against the pathogen may be measured. When detecting hormones such as insulin, the insulin may be used as the antigen. 
         [0061]    Accordingly, where a method or system is described herein to detect a primary binding pair molecule using a corresponding second binding pair molecule, it should be understood that the primary binding pair molecule may be an antibody or an antigen, and the second binding pair molecule may be a corresponding antigen or antibody, respectively. Similarly, where a method or system is described herein to detect an antibody or antigen, the method or system may be implemented to detect a corresponding antigen or antibody, respectively. 
         [0062]    Immunoassays may also be used to detect potential food allergens and chemicals, or drugs. 
         [0063]    Immunoassays include labeled immunoassays to provide a visual indication of a binding pair of molecules. Labeling may include an enzyme, radioisotopes, magnetic labels, fluorescence, agglutination, nephelometry, turbidimetry and western blot. 
         [0064]    Labeled immunoassays include competitive and non-competitive immunoassays. In a competitive immunoassay, an antigen in a sample competes with labeled antigen to bind with antibodies. The amount of labeled antigen bound to the antibody site is inversely proportional to the concentration of antigen in the sample. In noncompetitive immunoassays, also referred to as sandwich assays, antigen in a sample is bound to an antibody site. The labeled antibody is then bound to the antigen. The amount of labeled antibody on the site is directly proportional to the concentration of the antigen in the sample. 
         [0065]    Labeled immunoassays include enzyme-linked immuno-sorbent assays (ELISA). 
         [0066]    In an example immunoassay, a biological sample is tested for a presence of a primary binding pair molecule. A corresponding binding pair molecule that is specific to the primary binding pair molecule is immobilized on an assay substrate. The biological sample is contacted to the assay substrate. Any primary binding pair molecules in the biological sample attach to, or are captured by the corresponding binding pair molecules. The primary binding pair molecules are also contacted with labeled secondary binding pair molecules that attach to the primary binding pair molecules. This may be performed subsequent to, prior to, or simultaneously with the contacting of the primary binding pair molecule with the corresponding immobilized binding pair molecule. Un-reacted components of the biological sample and fluids may be removed, or washed from the assay substrate. Presence of the label on the assay substrate indicates the presence of the primary binding pair molecule in the biological sample. 
         [0067]    The label may include a directly detectable label, which may be visible to a human observer, such as gold particles in a colloid or solution, commonly referred to as colloidal gold. 
         [0068]    The label may include an indirect label, such an enzyme whereby the enzyme works on a substrate to produce a detectable reaction product. For example, an enzyme may attach to the primary binding pair molecule, and a substance that the enzyme converts to a detectable signal, such as a fluorescence signal, is contacted to the assay substrate. When light is directed at the assay substrate, any binding pair molecule complexes will fluoresce so that the presence of the primary binding pair molecule is observable. 
         [0069]    An immunoassay may utilize one or more fluid solutions, which may include a dilutent solution to fluidize the biological sample, a conjugate solution having the labeled secondary binding pair molecules, and one or more wash solutions. The biological sample and fluids may be brought into contact, concurrently or sequentially with the assay substrate. The assay substrate may include an assay surface or an assay membrane, prepared with a coating of the corresponding binding pair molecules. 
         [0070]    As described above, the second binding pair molecules may include an antigen that is specific to an antibody to be detected in a biological sample, or may include antibody that is specific to an antigen to be detected in the biological sample. By way of illustration, if the primary binding pair molecule to be detected is an antigen, the immobilized binding pair molecule and the secondary labeled binding pair molecule will be antibodies, both of which react with the antigen. When the antigen is present in the biological sample, the antigen will be immobilized by the immobilized antibody and labeled by the labeled secondary antibody, to form a sandwich-like construction, or complex. 
         [0071]    It is known that non-specific or un-reacted components may be beneficially removed using wash solutions, often between processes and/or prior to a label detection process, in order to improve sensitivity and signal-to-noise ratios of the assay. Other permutations are possible as well. For example, a conjugate solution, such as a labeled secondary binding pair molecule solution may be mixed with or act as a sample dilutent to advantageously transport the biological sample to the assay substrate, to permit simultaneous binding of the primary binding pair molecule and the labeled secondary binding pair molecule to the immobilized binding pair molecule. Alternatively, or additionally, the sample dilutent may include one or more detergents and/or lysing agents to advantageously reduce deleterious effects of other components of the biological sample such as cellular membranes, non-useful cells like erythrocytes and the like. 
         [0072]    Those skilled in the art will readily recognize that such fluid components and the order of the reactionary steps may be readily adjusted along with concentrations of the respective components in order to optimize detection or distinguishment of analytes, increase sensitivity, reduce non-specific reactions, and improve signal to noise ratios. 
         [0073]    As will be readily understood, if the secondary antibody is labeled with an enzyme instead of a fluorescent or other immediately detectable label, an additional substrate may be utilized to allow the enzyme to produce a reaction product which will be advantageously detectable. An advantage of using an enzyme based label is that the detectable signal may increase over time as the enzyme works on an excess of substrate to produce a detectable product. 
         [0074]      FIG. 1  is a process flowchart of a method  100  of detecting a primary binding pair molecule in a biological sample, using a substantially self-contained, point-of-care, user-initiated fluidic assay system. The primary binding pair molecule may correspond to an antibody or an antigen. 
         [0075]    At  102 , a biological sample is provided to the assay system. The biological sample may include one or more of a blood sample, a saliva sample, and a urine sample. The biological sample may be applied to a sample substrate within the assay system. 
         [0076]    At  104 , a fluidic actuator within the assay system is initiated by a user. The fluidic actuator may include a mechanical actuator, such as a compressed spring actuator, and may be initiated with a button, switch, or lever. The fluidic actuator may be configured to impart one or more of a physical force, pressure, centripetal force, gas pressure, gravitational force, and combinations thereof, on a fluid controller system within the assay system. 
         [0077]    At  106 , the biological sample is fluidized with a dilutent fluid. The dilutent fluid may flow over or through the sample substrate, under control of the fluid controller system. 
         [0078]    At  108 , the fluidized biological sample is contacted to a corresponding binding pair molecule that is specific to primary binding pair molecule. The corresponding binding pair molecule may be immobilized on an assay substrate within the assay system. The fluidized biological sample may flow over or through the assay substrate, under control of the fluid controller system. 
         [0079]    Where the fluidized biological sample includes the primary binding pair molecule, the primary binding pair molecule attaches to the corresponding binding pair molecule and becomes immobilized on the assay substrate. For example, where the second binding pair molecule includes a portion of a pathogen, and where the biological sample includes an antibody to the pathogen, the antibody attaches to the antigen immobilized at the assay substrate. 
         [0080]    At  110 , a labeled conjugate solution is contacted to the assay substrate, under control of the fluid controller system. The labeled conjugate solution includes a secondary binding pair molecule to bind with the primary binding pair molecule. Where the primary binding pair molecule is immobilized on the assay substrate with the corresponding binding pair molecule, the secondary binding pair molecule attaches to the immobilized primary binding pair molecule, effectively creating a sandwich-like construct of the primary binding pair molecule, the corresponding binding pair molecule, and the labeled secondary binding pair molecule. 
         [0081]    The secondary binding pair molecule may be selected as one that targets one or more proteins commonly found in the biological sample. For example, where the biological sample includes a human blood sample, the secondary binding pair molecule may include an antibody generated by a non-human animal in response to the one or more proteins commonly found in human blood. 
         [0082]    The secondary binding pair molecule may be labeled with human-visible particles, such as a gold colloid, or suspension of gold particles in a fluid such as water. Alternatively, or additionally, the secondary binding pair molecule may be labeled with a fluorescent probe. 
         [0083]    Where the labeled secondary binding pair molecule attaches to a primary binding pair molecule that is attached to a corresponding binding pair molecule, at  110 , the label is viewable by the user at  112 . 
         [0084]    Method  100  may be implemented to perform multiple diagnostic assays in an assay system. For example, a plurality of antigens, each specific to a different antibody, may be immobilized on one or more assay substrates within an assay system. Similarly, a plurality of antibodies, each specific to a different antigen, may be immobilized on one or more assay substrates within an assay system 
         [0085]      FIG. 2  is a block diagram of a portable, point-of-care, user-initiated fluidic assay system  200 , including a housing  202 , a user-initiated actuator  204 , a fluidic pump  206 , and an assay result viewer  218 . 
         [0086]    Pump  206  includes one or more fluid chambers  210 , to contain fluids to be used in an assay. One or more of fluid chambers  210  may have, without limitation, a volume in a range of 0.5 to 2 milliliters. 
         [0087]    Pump  206  includes a sample substrate  214  to hold a sample. Sample substrate  214  may include a surface or a membrane positioned within a cavity or a chamber of housing  202 , to receive one or more samples, as described above. 
         [0088]    Sample substrate  214  may include a porous and/or absorptive material, which may be configured to absorb a volume of liquid in a range of 10 to 500 μL, including within a range of up to 200 μL, and including a range of approximately 25 to 50 μL. 
         [0089]    Pump  206  includes an assay substrate  216  to hold an assay material. Assay substrate  216  may include a surface or a membrane positioned within a cavity or chamber of housing  202 , to receive one or more assay compounds or biological components, such as an antigen or an antibody, as described above. 
         [0090]    Fluid chambers  210  may include a waste fluid chamber. 
         [0091]    Pump  206  further includes a fluid controller system  208 , which may include a plurality of fluid controllers, to control fluid flow from one or more fluid chambers  212  to one or more of sample substrate  214  and assay substrate  216 , responsive to actuator  204 . 
         [0092]    Actuator  204  may include a mechanical actuator, which may include a compressed or compressible spring actuator, and may include a button, switch, lever, twist-activator, or other user-initiated feature. 
         [0093]    Assay result viewer  218  may include a display window disposed over an opening through housing  202 , over assay substrate  216 . 
         [0094]      FIG. 3  is a perspective view of a portable, point-of-care, user-initiated fluidic assay system  300 , including a housing  302 , a user-initiated actuator button  304 , a sample substrate  306 , and a sample substrate cover  308 . Sample substrate cover  308  may be hingedly coupled to housing  302 . 
         [0095]    Assay system  300  further includes an assay result viewer  310 , which may be disposed over an assay substrate. Assay result view  310  may be disposed at an end of assay system  300 , as illustrated in  FIG. 3 , or along a side of assay system  300 . 
         [0096]    Assay system  300  may have, without limitation, a length in a range of 5 to 8 centimeters and a width of approximately 1 centimeter. Assay system  300  may have a substantially cylindrical shape, as illustrated in  FIG. 3 , or other shape. 
         [0097]    Assay system  300 , or portions thereof, may be implemented with one or more substantially rigid materials, and/or with one or more flexible or pliable materials, including, without limitation, polypropylene. 
         [0098]    Example portable, point-of-care, user-initiated fluidic assay systems are disclosed further below. 
         [0099]      FIG. 4  is a process flowchart of a method  400  of preparing a portable, point-of-care, user-initiated fluidic assay system. Method  400  is described below with reference to assay system  200  in  FIG. 2 , for illustrative purposes. Method  400  is not, however, limited to the example of  FIG. 2 . 
         [0100]    At  402 , a binding pair molecule is immobilized on an assay substrate, such as assay substrate  216  in  FIG. 2 . The binding pair molecule may include an antigen specific to an antibody, or an antibody specific to an antigen. 
         [0101]    At  404 , a first one of fluid chambers  210  is provided with a dilutent solution to fluidize a sample. 
         [0102]    At  406 , a second one of fluid chambers  210  is provided with a labeled secondary binding pair molecule solution. 
         [0103]    At  408 , a third one of fluid chambers  210  is provided with a wash solution, which may include one or more of a saline solution and a detergent. The wash solution may be substantially similar to the dilutent solution. 
         [0104]      FIG. 5  is a process flowchart of a method  500  of using an assay system prepared in accordance with method  400 . Method  500  is described below with reference to assay system  200  in  FIG. 2 , and assay system  300  in  FIG. 3 , for illustrative purposes. Method  500  is not, however, limited to the examples of  FIG. 2  and  FIG. 3 . 
         [0105]    At  502 , a sample is provided to a sample substrate, such as sample substrate  214  in  FIG. 2 , and sample substrate  306  in  FIG. 3 . 
         [0106]    At  504 , a user-initiated actuator is initiated by the user, such as user-initiated activator  204  in  FIG. 2 , and button  304  in  FIG. 3 . The user initiated actuator acts upon a fluid controller system, such as fluid controller system  208  in  FIG. 2 . 
         [0107]    At  506 , the dilutent solution flows from first fluid chamber and contacts the sample substrate and the assay substrate, under control of the fluid controller system. 
         [0108]    As the dilutent fluid flows over or through the sample substrate, the sample is dislodged from the sample substrate and flows with the dilutent solution to the assay substrate. 
         [0109]    At  508 , the labeled secondary binding pair solution flows from the second fluid chamber and contacts the assay substrate, under control of the fluid controller system. The labeled secondary binding pair solution may flow directly to the assay substrate or may flow over or through the sample substrate. 
         [0110]    At  510 , the wash solution flows from the third fluid chamber and washes the assay substrate, under control of fluid controller system  208 . The wash solution may flow from the assay substrate to a waste fluid chamber, 
         [0111]    At  512 , assay results are viewable, such as at assay result viewer  218  in  FIG. 2 , and assay result viewer  310  in  FIG. 3 . 
         [0112]    An assay substrate may include a nitrocellulose-based membrane, available from Invitrogen Corporatation, of Carlsbad, Calif. 
         [0113]    Preparation of a nitrocellulose-based membrane may include incubation for approximately thirty (30) minutes in a solution of 0.2 mg/mL protein A, available from Sigma-Aldrich Corporation, of St. Louis, Mo., in a phosphate buffered saline solution (PBS), and then dried at approximately 37° for approximately fifteen (15) minutes. 1 μL of PBS may be added to the dry membrane and allowed to dry at room temperature. Alternatively, 1 μL of an N-Hydroxysuccinimide (NHS) solution, available from Sigma-Aldrich Corporation, of St. Louis, Mo., may be added to the dry membrane and allowed to dry at room temperature. 
         [0114]    An assay method and/or system may utilize or include approximately 100 μL of PBS/0.05% Tween wash buffer, available from Sigma-Aldrich Corporation, of St. Louis, Mo., and may utilize or include approximately 100 μL of protein G colloidal gold, available from Pierce Corporation, of Rockland, Ill.. 
         [0115]    An assay method and/or system may be configured to test for Chlamydia, and may utilize or include a sample membrane treated with wheat germ agglutinin, to which an approximately 50 μL blood sample is applied. Approximately 150 μL of a lysing solution may then be passed through the sample membrane and then contacted to an assay substrate. Thereafter, approximately 100 μL of a colloidal gold solution may be contacted to the assay substrate. Thereafter, approximately 500 μL of a wash solution, which may include the lysing solution, may be contacted to the assay membrane without passing through the sample membrane. 
         [0116]    Additional features and embodiments are disclosed below. Based on the description herein, one skilled in the relevant art(s) will understand that features and embodiments described herein may be practiced in various combinations with one another. 
       I. Example Multiple Fluid Chamber, Serial Fluid Pump 
       [0117]      FIGS. 6 and 7  are cross-sectional block diagrams of a pump  600 , including a housing  602  having an inner wall surface  604 , defining a cavity  606  therein. 
         [0118]    A fluid flow controller or plunger  612  is disposed within housing  602 . Plunger  612  separates or defines first and second fluid chambers  618   a  and  618   b.  Plunger  612  is movable between a first position, as illustrated in  FIG. 6 , and a second position, as illustrated in  FIG. 7 . An outlet  608  in a base  624  of the housing  602  is in communication with second fluid chamber  618   a.  Plunger  612  is controllable to dispense fluid from fluid chamber  618   a  through outlet  608 . Outlet  608  may lead to one or more other fluid chambers, which may include one or more of a sample substrate and an assay substrate. 
         [0119]    A stop  614  prevents plunger  612  from obstructing or sealing outlet  608  when plunger  612  is in the second position ( FIG. 7 ). Stop  614  can be implemented in a variety of ways.  FIG. 8  is a cross-sectional view of housing  602 , above base  624  according to view AA ( FIG. 7 ), wherein stop  614  includes one or more protrusions extending from base  624  into cavity  606 . Alternatively, stop  614  can include one or more protrusions extending from housing inner wall surface  604  into cavity  606 , and/or extending from a surface  628  of plunger  612 . 
         [0120]    As illustrated in  FIG. 7 , when plunger  612  is in the second position, second fluid chamber  618   b  is in fluid communication with first fluid chamber  618   a  through a passageway or gate  610 . The second position is referred to herein as a functionally open position. 
         [0121]    Gate  610  may be formed, etched, engraved, carved, or otherwise implemented or imparted as one or more channels on surface  604  and/or as one or more passages within housing inner wall  604 , wherein openings through housing inner wall surface  604  expose the one or more passages to the cavity  606 . 
         [0122]    Gate  610  and plunger  612  are configured and/or dimensioned so that plunger  612  obstructs, blocks, and/or seals gate  610 , or a portion thereof, from second fluid chamber  618   b  when plunger  612  is in the first position, thereby isolating first fluid chamber  618   a  from second fluid chamber  118   b,  as illustrated in  FIG. 6 . The first position is referred to herein as a functionally closed position. 
         [0123]    In the example of  FIGS. 6 and 7 , gate  610  has a length  622  that is dimensionally greater than a plunger edge height  620 . In the functionally closed position, plunger  612  blocks at least a portion of gate  610 , as illustrated in  FIG. 6 , or is positioned more distant from base  624 , so that first fluid chamber  618   a  is isolated from second fluid chamber  118   b.    
         [0124]    Plunger  612  can be solid or hollow. Plunger surfaces  626  and  628  can be substantially flat, concave, convex, and/or combinations thereof. 
         [0125]    Plunger  612  is controllable by, for example and without limitation, centripetal force, gas pressure, physical pressure, including manual activation, gravitational force, or combinations thereof. 
         [0126]    In operation, as plunger  612  moves from the non-depressed or functionally closed position of  FIG. 6 , to the depressed or functionally open position of  FIG. 7 , fluid within first fluid chamber  618   a  is expelled through outlet  608 . When plunger  612  reaches the depressed or functionally open position of  FIG. 7 , first fluid chamber  618   a  is in fluid communication with second fluid chamber  618   b  through gate  610 , allowing fluid in second fluid chamber  618   b  to be expelled through gate  610  and through outlet  608 , as illustrated by flow indicating arrows  702 . Fluid in second fluid chamber  618   b  can be expelled by, for example and without limitation, centripetal force, gas pressure, physical pressure, including manual activation, gravitational force, or combinations thereof, optionally including a second plunger. 
         [0127]    Based on the description herein, one skilled in the relevant art(s) will understand that gate  610  can be implemented with other configurations as well, including configurations where gate  610 , or a portion thereof, is implemented within plunger  612 . Such other configurations are within the spirit and scope of the present disclosure. 
         [0128]    One or more additional plungers and corresponding gates are optionally implemented. Additional fluid chambers can be controlled to serially dispense fluids therein, sequentially or out-of-order, and/or to internally mix fluids from multiple fluid chambers. Example embodiments are described below for illustrative purposes. 
         [0129]    Pump  600  may be operated in reverse as a vacuum device. 
       II. Serial Dispensing 
       [0130]      FIGS. 9 and 10  are cross-sectional block diagrams of an example multiple fluid chamber, serially dispensing pump  900 . Pump  900  includes plungers  912   a,    912   b,  and  912   c,  defining fluid chambers  918   a  through  918   d.  Pump  900  further includes stops  914   a  through  914   c,  which can be configured similar to, or different than stop  614  in  FIGS. 6 ,  7  and  8 . 
         [0131]    In the example of  FIGS. 9 and 10 , plungers  912   a  through  912   c  are longitudinally aligned with one another within a housing cavity  906 , and are movable between functionally closed positions, as illustrated in  FIG. 9 , and functionally open positions, as illustrated in  FIG. 10 . The functionally open and closed positions of plungers  912   a,    912   b,  and  912   c  are generally defined with respect to whether they allow or retard fluid communication with respect to one or more fluid chambers. 
         [0132]    Pump  900  includes gates  910   a  through  910   c.  In  FIG. 9 , when plunger  912   a  is in its functionally open position, fluid chambers  918   a  and  918   b  are in fluid communication with one another through gate  910   a.  In  FIG. 10 , when plunger  912   b  is in its functionally open position, fluid chambers  918   b  and  918   c  are in fluid communication with one another through gate  910   b.  When plunger  912   c  is in its functionally open position, fluid chambers  918   c  and  918   d  are in fluid communication with one another through gate  910   c.    
         [0133]    Plungers  912   a  through  912   c  and gates  910   a  through  910   c  are configured, dimensioned, positioned, and/or controlled to allow fluids within the fluid chambers  918   a  through  918   d  to be expelled or dispensed serially. Example methods and systems for controlling plungers  912  are described below. 
         [0134]    In the example of  FIGS. 9 and 10 , gates  910   a  through  910   c  have respective gate lengths  922 ,  906 , and  908  ( FIG. 10 ). Gate length  922  is greater than gate length  906 , which is greater than gate length  908 . Gates  910   a  through  910   c  are laterally dispersed from one another so as not to interfere with one another. A portion of gate  910   a  longitudinally overlaps a portion of gate  910   b.  A portion of gate  910   b  longitudinally overlaps a portion of gate  910   c.  Plungers  912   a  through  912   c  have respective edge heights  920 ,  912 , and  914 . Edge height  920  is greater than edge height  912 , which is greater than edge height  914 . Gate length  122  is greater than edge height  920 . Gate length  906  is greater than edge height  912 . Gate length  908  is greater than edge height  914 . Other dimensions may be implemented. 
         [0135]    In operation, as plunger  112   a  moves from its functionally closed position to its functionally open position, fluid in fluid chamber  918   a  is expelled through outlet  924 . Outlet  924  may lead to one or more other fluid chambers, which may include one or more of a sample substrate and an assay substrate. Plungers  912   b  and  912   c  typically move together with plunger  912   a,  thereby maintaining a substantially constant volume in each of fluid chambers  918   b  through  918   c.    
         [0136]    When plunger  912   a  reaches its functionally open position, fluid chamber  918   b  is in fluid communication with fluid chamber  918   a  and outlet  908  through gate  910   a.  Plunger  912   b  is then moved from its functionally closed position to its functionally open position, thereby expelling or dispensing fluid in fluid chamber  918   b  through gate  910   a  and outlet  908 , as illustrated at  1002  in  FIG. 10 . 
         [0137]    When plunger  912   b  reaches its functionally open position, fluid chamber  918   c  is in fluid communication with fluid chamber  918   b  through gate  910   b,  and is thus in fluid communication with fluid chamber  918   a  and outlet  908  through gate  910   a.  Plunger  912   c  is then moved from its functionally closed position to its functionally open position, thereby expelling or dispensing fluid in fluid chamber  918   c  through gate  910   b,  gate  910   a,  and outlet  908 , as illustrated at  1004  and  1002  in  FIG. 10 . 
         [0138]    When plunger  912   c  reaches its functionally open position, fluid chamber  918   d  is in fluid communication with fluid chamber  918   c  through gate  910   c,  and is thus in fluid communication with fluid chamber  918   b  through gate  910   b,  and fluid chamber  918   a  and outlet  908  through gate  910   a.  Fluid in fluid chamber  918   d  is then expelled or dispensed through gates  910   c,    910   b,  and  910   a,  and outlet  908 , as illustrated at  1006 ,  1004 , and  1002  in  FIG. 10 . 
         [0139]    Movement of plungers  912  can be controlled in one or more of a variety of ways. For example, pump  900  can include a stem  920  ( FIG. 9 ) coupled to plunger  912   c  to control plunger  912   c  through applied force, such as a compressed spring or other mechanical actuator, and/or an inlet  922  to apply a gas and/or fluid pressure and/or vacuum to fluid chamber  918   d.    
         [0140]    As stem  920  is moved into cavity  906 , and/or as gas or fluid pressure is applied through inlet  922 , plunger  912  is forced in the direction of outlet  908 . Since the plungers  912  are in functionally closed positions, resultant pressure in fluid chamber  918   c  forces plunger  912   b  in the direction of outlet  908 , which increases pressure in fluid chamber  918   b,  which forces plunger  912   a  in the direction of outlet  908 , dispensing fluid from fluid chamber  918   a  through outlet  908 . Continued force/pressure applied by stem  920  and/or inlet  922  cause plungers  912   b  and  912   c  to continue to move as described above, serially dispensing fluid from fluid chamber  918   b,  then from fluid chamber and  918   c.    
         [0141]    Based on the description herein, one skilled in the relevant art(s) will understand that a multiple fluid, serial output, dispenser or pump can be implemented with other housing shapes and forms, and other plunger alignment, movement, and control schemes. 
       III. Serial Mixing 
       [0142]      FIGS. 11 through 14  are cross-sectional block diagrams of an example multiple fluid chamber, serial mixing pump  1100 . 
         [0143]    Pump  1100  includes plungers  1112   a  through  1112   d,  fluid chambers  1118   a  through  1118   c,  and gates  1110   a  through  1110   c.  In the example below, plungers  1112   a  through  1112   d  are controlled to move fluid from fluid chamber  1118   c  to fluid chamber  1118   a,  then to move fluid from fluid chamber  1118   b  to fluid chamber  1118   a,  where the fluids mix. The mixed fluid in fluid chamber  1118   a  is then pumped to another fluid chamber through gate  1110   a,  or/or expelled through an outlet, The outlet may lead to one or more other fluid chambers, which may include one or more of a sample substrate and an assay substrate. 
         [0144]      FIG. 11  illustrates pump  1100  at an initial state. 
         [0145]      FIG. 12  illustrates pump  1100  as plunger  1112   d  moves in the direction of arrow  1120 , moving fluid from fluid chamber  1118   c  to fluid chamber  1118   a  through gate  1110   c.  Plunger  1112   a  simultaneously moves in the direction of arrow  1122  to accommodate fluid from fluid chamber  1118   c.    
         [0146]    When plunger  1112   d  reaches plunger  1112   c,  plungers  1112   c  and  1112   b  move in tandem with plunger  11122 , whereby gate  1110   c  is sealed by plunger  1112   d  and gate  1110   b  is opened by plunger  1112   b.  Plungers  1112   c  and  1112   d  continue moving, thereby expelling fluid in fluid chamber  1118   b  to fluid chamber  1118   a,  where it mixes with the fluid from fluid chamber  1118   c,  as illustrated in  FIG. 13 . Plunger  1112   a  continues to move as well, thereby accommodating the fluid from fluid chamber  1118   b.    
         [0147]    In  FIG. 14 , plunger  1112   a  moves slightly more, thereby opening gate  1110   a.  Plunger  1112   b,  and optionally plungers  1112   c  and  1112   d  move to expel the fluid in fluid chamber  1118   a  through gate  1110   a.  Gate  1110   a  may lead to one or more other fluid chambers, which may include one or more of a sample substrate and an assay substrate. 
         [0148]    Movement of plungers  1112  can be controlled in one or more of a variety of ways. For example, pump  1100  can include a stem  1120  coupled to plunger  1112   d,  and/or an inlet  1122 , to control plungers  1112  substantially as described above with respect to pump  900 . Control of plungers  1112  is not, however, limited to the examples of stem  1120  or inlet  1122 . 
       IV. Simultaneous Mixing 
       [0149]      FIGS. 15 through 17  are cross-sectional block diagrams of a multiple fluid chamber, simultaneous mixing pump  1500 . 
         [0150]    Pump  1500  includes plungers  1512   a  through  1512   d,  fluid chambers  1518   a  through  1518   c,  and gates  1510   a  through  1510   c.  In the example below, plungers  1512   a  through  1512   d  are controlled to simultaneously move fluid from fluid chambers  1518   b  and  1518   c  to fluid chamber  1518   a,  where they mix with one another. The mixed fluid in fluid chamber  1518   a  is then pumped to another fluid chamber through gate  1510   a,  or/or expelled through an outlet. The outlet may lead to one or more other fluid chambers, which may include one or more of a sample substrate and an assay substrate. 
         [0151]    In  FIGS. 15 and 16 , plunger  1512   d  moves in the direction of arrow  1520 , moving fluid from fluid chamber  1518   c  to fluid chamber  1518   a  through gate  1510   c.  Simultaneously, plunger  1512   c  moves in the direction of arrow  1722 , moving fluid from fluid chamber  1518   b  to fluid chamber  1518   a  through gate  1510   b.  Plunger  1512   a  simultaneously moves in the direction of arrow  1524  so that fluid chamber  1518   a  accommodates the fluids from fluid chambers  1518   b  and  1818   c.    
         [0152]    In  FIGS. 15 and 16 , plunger  1512   a  seals gate  1510   a.  In  FIG. 17 , after the fluids from fluid chambers  1518   b  and  1518   c  have moved into fluid chamber  1518   a,  plunger  1512   a  moves in the direction of arrow  1524 , thereby opening gate  1510   a,  and plunger  1512   b  moves in the direction of arrow  1720 , thereby closing gates  1510   b  and  1510   c.  Plunger  1512   b,  and optionally plungers  1512   c  and  1512   d,  continues to move in the direction of arrow  1720 , thereby expelling the mixed fluid in fluid chamber  1518   a,  through gate  1510   a.    
         [0153]    Movement of plungers  1512  can be controlled in one or more of a variety of ways, such as described above with respect to pump  400 , and/or as described below with respect to  FIGS. 16-19 . Control of plungers  1512  is not, however, limited to these examples. 
       V. Simultaneous Mixing, Opposing Directions 
       [0154]      FIGS. 18 through 20  are cross-sectional block diagrams of a multiple fluid chamber, simultaneous mixing pump  1800 , in which fluids flow from opposing directions into a mixing chamber. 
         [0155]    Pump  1800  includes plungers  1812   a  through  1812   d,  fluid chambers  1818   a  through  1818   c,  and gates  1810   a  through  1810   c.  In the example below, plungers  1812   b  and  1812   c  are controlled to simultaneously move fluid from fluid chambers  1818   a  and  1818   c  to fluid chamber  1818   b,  where they mix with one another. The mixed fluid in fluid chamber  1818   b  is then pumped to another fluid chamber through gate  1810   a,  or/or expelled through an outlet. 
         [0156]    In  FIGS. 18 and 19 , plunger  1812   b  moves in the direction of arrow  1820 , moving fluid from fluid chamber  1818   a  to fluid chamber  1818   b  through gate  1810   b.  Simultaneously, plunger  1812   c  moves in the direction of arrow  1822 , moving fluid from fluid chamber  1818   c  to fluid chamber  1818   b  through gate  1810   c.    
         [0157]    In  FIGS. 18 and 19 , plunger  1812   b  seals gate  1810   a.  In  FIG. 20 , after the fluids from fluid chambers  1818   a  and  1818   c  have moved into fluid chamber  1818   b,  plungers  1812   a  and  1812   b  move slightly in the direction of arrow  2020 , thereby opening gate  1810   a.  Plunger  1812   c,  and optionally plunger  1812   d  move in the direction of arrow  2022 , thereby expelling the mixed fluid in fluid chamber  1818   b  through gate  1810   a.    
         [0158]    Movement of plungers  1812  can be controlled in one or more of a variety of ways, such as described above with respect to pump  400 . Control of plungers  1812  is not, however, limited to these examples. 
       VI. Nested Plungers 
       [0159]      FIG. 22  is a cross-sectional perspective view of a portion of an assay system  2200  including a housing portion  2202  and a fluid controller system, including a plurality of fluid controllers, or plungers  2204 ,  2206 , and  2208 . Fluid controllers  2204 ,  2206 , and  2208  define a plurality of fluid chambers, illustrated here as first, second, and third fluid chambers  2210 ,  2212 , and  2214 , respectively. Fluid controllers  2204 ,  2206 , and  2208  are slideably nested within one another. 
         [0160]    Housing portion  2202  includes a sample chamber  2216  to receive a sample, and may include a sample substrate, membrane or pad  2218 . Housing portion  2202  may include a cover mechanism such as a cover portion  2220 , which may be removable or hingedly coupled to housing portion  2202 , as described above with respect to  FIG. 3 . Housing portion  2202  includes a sample chamber inlet  2222  and a sample chamber outlet  2224 . 
         [0161]    Housing portion  2202  includes an assay chamber  2226  and an assay chamber inlet  2228 , and may include an assay substrate, membrane or pad  2228  to capture, react, and/or display assay results. 
         [0162]    Housing portion  2202  includes an assay result viewer, illustrated here as a display window  2232  disposed over assay chamber  2228 . 
         [0163]    Housing portion  2202  includes a waste fluid chamber  2234  to receive fluids from assay chamber  2226 . 
         [0164]    Housing portion  2202  includes a transient fluid chamber  2236  having one or more fluid channels  2238 , also referred to herein as a fluid controller bypass channel. 
         [0165]    Housing portion  2202  further includes one or more other fluid channels  2258 . 
         [0166]    First fluid chamber  2210  includes a fluid chamber outlet  2260 , illustrated here as a space between fluid controller  2206  and an inner surface of hosing portion  2202 . 
         [0167]    Second fluid chamber  2212  includes a fluid chamber outlet  2248 , illustrated here as a gate or passage through fluid controller  2204 . 
         [0168]    Third fluid chamber  2214  includes a fluid chamber outlet  2254 , illustrated here as a gate through fluid controller  2206 . 
         [0169]    Fluid controllers  2204 ,  2206 , and  2208  include one or more sealing mechanisms, illustrated here as O-rings  2240  and  2242 , O-rings  2244  and  2246 , O-rings  2250  and  2252 , and O-ring  2256 . 
         [0170]    Example operation of assay system  2200  is described below with respect to  FIGS. 23-27 . 
         [0171]      FIG. 23  is a cross-sectional block diagram of assay system  2200 , wherein fluid controllers  2204 ,  2206 , and  2208  are illustrated in corresponding initial or functionally closed first positions. When fluid controllers  2204 ,  2206 , and  2208  are in the initial positions, O-ring  2240  is sealingly engaged against an inner surface of housing portion  2202 , between first fluid chamber outlet  2260  and sample chamber inlet  2222 , to substantially preclude fluid flow from fluid chamber  2210 . Similarly, O-rings  2244  and  2246  are sealingly engaged against an inner surface of housing portion  2202  to substantially preclude fluid flow from fluid chamber  2212  through second fluid chamber outlet  2248 . O-rings  2250  and  2252  are sealingly engaged against an inner surface of housing portion  2202  to substantially preclude fluid flow from fluid chamber  2214  through third fluid chamber outlet  2254 . 
         [0172]    O-Rings  2244 ,  2246 ,  2250 ,  2252 , and  2256  cause fluid controllers  2204 ,  2206 , and  2208  to be pressurizably engaged with one another, such that a force applied to fluid controller  2208 , in the direction of fluid controllers  2206  and  2204 , causes the fluid controller system to serially move into functionally open positions with respect to first, second, and third fluid chambers  2210 ,  2212 , and  2214 , as described below with respect to  FIGS. 24-27 . 
         [0173]      FIG. 24  is a cross-sectional block diagram of assay system  2200 , wherein the fluid controller system has moved in a direction of arrow  2402 , relative to housing portion  2202 , to align first fluid chamber outlet  2260  with a fluid path  2404  to assay chamber  2226 . This is referred to herein as a first functionally open position. Fluid path  2404  includes sample chamber inlet  2222 , sample chamber  2216 , sample chamber outlet  2224 , transient fluid chamber  2236 , and assay chamber inlet  2228 . 
         [0174]    As continued force is applied to fluid controller  2208 , fluid controllers  2204 ,  2206 , and  2208  continue to move in the direction of arrow  2402 , to expel fluid from first fluid chamber  2210  to assay chamber  2226 , through fluid path  2204 . The fluid may flow over or through assay substrate  2230 , to waste fluid chamber  2234 . 
         [0175]      FIG. 25  is a cross-sectional block diagram of assay system  2200 , wherein the fluid controller system has moved further in the direction of arrow  2402 , to align second fluid chamber outlet  2248  with a fluid path  2504  to assay chamber  2226 . This is referred to herein as a second functionally open position. Fluid path  2504  includes fluid channel  2258  to bypass O-ring  2246  and first fluid controller  2204 , first fluid chamber outlet  2260 , transient fluid chamber  2236 , fluid channel  2238  to bypass O-rings  2240  and  2242 , and assay chamber inlet  2228 . 
         [0176]    As continued force is applied to fluid controller  2208 , fluid controllers  2206  and  2208  continue to move in the direction of arrow  2402 , to expel fluid from second fluid chamber  2212  to assay chamber  2226 , through fluid path  2504 . The fluid may flow over or through assay substrate  2230 , to waste fluid chamber  2234 . 
         [0177]      FIG. 26  is a cross-sectional block diagram of assay system  2200 , wherein the fluid controller system has moved further in the direction of arrow  2402 , to align third fluid chamber outlet  2254  with a fluid path  2604  to assay chamber  2226 . This is referred to herein as a third functionally open position. Fluid path  2604  includes second fluid chamber outlet  2248 , fluid channel  2258 , first fluid chamber outlet  2260 , transient fluid chamber  2236 , and assay chamber inlet  2228 . 
         [0178]    As continued force is applied to fluid controller  2208 , fluid controller  2208  continues to move in the direction of arrow  2402 , to expel fluid from third fluid chamber  2214  to assay chamber  2226 , through fluid path  2604 . The fluid may flow over or through assay substrate  2230 , to waste fluid chamber  2234 . 
         [0179]      FIG. 27  is a cross-sectional block diagram of assay system  2200 , wherein the fluid controller system has expelled fluid from third fluid chamber  2214 . 
         [0180]    Assay system  2200  may include an actuator system, which may be configured to act upon third fluid controller  2208 . 
         [0181]      FIG. 28  is a cross-sectional perspective view of a portion of an assay system  2800  including a housing portion  2802  and a fluid controller system, including a plurality of fluid controllers, or plungers  2804 ,  2806 , and  2808 . Fluid controllers  2804 ,  2806 , and  2808  define a plurality of fluid chambers, illustrated here as first, second, and third fluid chambers  2810 ,  2812 , and  2814 , respectively. Fluid controller  2808  is slideably nested within fluid controller  2806 . 
         [0182]    Housing portion  2802  includes a sample chamber  2816  to receive a sample, and may include a sample substrate  2818 , which may include a surface of sample chamber  2816  or membrane therein. Housing portion  2802  may include a cover mechanism such as a cover portion  2820 , which may be removable or hingedly coupled to housing portion  2802 , as described above with respect to  FIG. 3 . Housing portion  2802  includes a sample chamber inlet  2822  and a sample chamber outlet  2824 . 
         [0183]    Housing portion  2802  includes an assay chamber  2826  and an assay chamber inlet  2828 , and may include an assay substrate  2828  to capture, react, and/or display assay results. Assay substrate may include a surface of assay chamber  2826  or a membrane therein. 
         [0184]    Housing portion  2802  includes an assay result viewer, illustrated here as a display window  2832  disposed over assay chamber  2828 . 
         [0185]    Housing portion  2802  includes a waste fluid chamber  2834  to receive fluids from assay chamber  2826 . 
         [0186]    Housing portion  2802  includes a transient fluid chamber  2836  having one or more fluid channels  2838 , also referred to herein as a fluid controller bypass channel. 
         [0187]    Housing portion  2802  further includes fluid channels  2858  and  2862 . 
         [0188]    First fluid chamber  2810  includes a fluid chamber outlet  2860 , illustrated here as a space between fluid controller  2806  and an inner surface of hosing portion  2802 . 
         [0189]    Second fluid chamber  2812  includes a fluid chamber outlet  2848 , illustrated here as a space between fluid controller  2804  and an inner surface of hosing portion  2802 . 
         [0190]    Third fluid chamber  2814  includes a fluid chamber outlet  2854 , illustrated here as a gate or passage through fluid controller  2806 . 
         [0191]    Fluid controllers  2804 ,  2806 , and  2808  include one or more sealing mechanisms, illustrated here as O-rings  2840  and  2842 , O-rings  2844  and  2846 , and O-ring  2856 . 
         [0192]    Example operation of assay system  2800  is described below with respect to  FIGS. 29-33 . 
         [0193]      FIG. 29  is a cross-sectional block diagram of assay system  2800 , wherein the fluid controller system, including fluid controllers  2804 ,  2806 , and  2808 , is illustrated in corresponding initial or functionally closed positions. When fluid controllers  2804 ,  2806 , and  2808  are in the initial positions, O-ring  2842  is sealingly engaged against an inner surface of housing portion  2802 , between first fluid chamber outlet  2860  and sample chamber inlet  2822 , to substantially preclude fluid flow from fluid chamber  2810 . Similarly, O-ring  2840  is sealingly engaged against an inner surface of housing portion  2802  to substantially preclude fluid flow from fluid chamber  2812  through second fluid chamber outlet  2848 . O-rings  2844  and  2846  are sealingly engaged against an inner surface of housing portion  2802  to substantially preclude fluid flow from fluid chamber  2814  through third fluid chamber outlet  2854 . 
         [0194]    O-Rings  2840 ,  2842 ,  2844 ,  2846 , and  2856  cause fluid controllers  2804 ,  2806 , and  2808  to be pressurizably engaged with one another, such that a force applied to fluid controller  2808 , in the direction of fluid controllers  2806  and  2804 , causes the fluid controller system to serially move into functionally open positions with respect to first, second, and third fluid chambers  2810 ,  2812 , and  2814 , as described below with respect to  FIGS. 30-33 . 
         [0195]      FIG. 30  is a cross-sectional block diagram of assay system  2800 , wherein the fluid controller system has moved in a direction of arrow  3002 , relative to housing portion  2802 , to align first fluid chamber outlet  2860  with a fluid path  3004  to assay chamber  2826 . This is referred to herein as a first functionally open position. Fluid path  3004  includes sample chamber inlet  2822 , sample chamber  2816 , sample chamber outlet  2824 , transient fluid chamber  2836 , and assay chamber inlet  2828 . 
         [0196]    As continued force is applied to fluid controller  2808 , fluid controllers  2804 ,  2806 , and  2808  continue to move in the direction of arrow  3002 , to expel fluid from first fluid chamber  2810  to assay chamber  2826 , through fluid path  2804 . The fluid may flow over or through assay substrate  2830 , to waste fluid chamber  2834 . 
         [0197]      FIG. 31  is a cross-sectional block diagram of assay system  2800 , wherein the fluid controller system has moved further in the direction of arrow  3002 , to align second fluid chamber outlet  2848  with a fluid path  3104  to assay chamber  2826 . This is referred to herein as a second functionally open position. Fluid path  3104  includes fluid channel  2858  to bypass O-ring  2840  and first fluid controller  2804 , first fluid chamber outlet  2860 , transient fluid chamber  2836 , fluid channel  2838  to bypass O-ring  2842 , and assay chamber inlet  2828 . 
         [0198]    As continued force is applied to fluid controller  2808 , fluid controllers  2806  and  2808  continue to move in the direction of arrow  3002 , to expel fluid from second fluid chamber  2812  to assay chamber  2826 , through fluid path  3104 . The fluid may flow over or through assay substrate  2830 , to waste fluid chamber  2834 . 
         [0199]      FIG. 32  is a cross-sectional block diagram of assay system  2800 , wherein the fluid controller system has moved further in the direction of arrow  3002 , to align third fluid chamber outlet  2848  with a fluid path  3204  to assay chamber  2826 . This is referred to herein as a third functionally open position. Fluid path  3204  includes fluid channel  2862  to bypass O-ring  2846  and second flow controller  2806 , fluid channel  2858 , first fluid chamber outlet  2860 , transient fluid chamber  2836 , and assay chamber inlet  2828 . 
         [0200]    As continued force is applied to fluid controller  2808 , fluid controller  2808  continues to move in the direction of arrow  3002 , to expel fluid from third fluid chamber  2814  to assay chamber  2826 , through fluid path  3204 . The fluid may flow over or through assay substrate  2830 , to waste fluid chamber  2834 . 
         [0201]      FIG. 33  is a cross-sectional block diagram of assay system  2800 , wherein the fluid controller system has expelled fluid from third fluid chamber  2814 . 
         [0202]    Assay system  2800  may include an actuator system, which may be configured to act upon third fluid controller  2808 . 
         [0203]    One or more inlets, outlets, channels, and fluid pathways as described herein with respect to assay system  2200  and assay system  2800  may be implemented as one or more of gates and passageways as described in one or more preceding examples, an may include one or more of:
       a fluid channel within an inner surface of a housing;   a fluid passage within a housing, having a plurality of openings through an inner surface of the housing;   the fluid passage through a fluid controller; and   a fluid channel formed within an outer surface of one of the fluid controllers.       
 
         [0208]    One or more inlets, outlets, channels, fluid paths, gates, and passageways, as described herein, may include one or more flow restrictors, such as check valves, which may include a frangible check valve, to inhibit fluid flow when a pressure difference across the flow restrictor valve is below a threshold. 
       VII. Example Actuator Systems 
       [0209]    A user-initiated actuator system may include one or more of a mechanical actuator, an electrical actuator, an electro-mechanical actuator, and a chemical reaction initiated actuator. Example user-initiated actuator systems are disclosed below, one or more of which may be implemented with example pumps disclosed above. 
         [0210]      FIG. 34  is cross-sectional view of a mechanical actuator system  3400 . Actuator system  3400  includes a button  3402  slideably disposed through an opening  3404  of an outer housing portion  3406 , and through an opening  3408  of a frangible inner wall  3410  of outer housing portion  3406 . Button  3402  includes a detent  3412  that extends beyond openings  3404  and  3408  to secure button  3402  between housing portion  3406  and frangible inner wall  3410 . 
         [0211]    Actuator system  3400  includes a compressible spring  3414  having a first end positioned within a cavity  3416  of button  3402 , and a second end disposed within a cavity  3418  of a member  3420 . Member  3420  may be coupled to, or may be a part of a fluid controller system, such a part of a plunger or fluid controller as described and illustrated in one or more examples herein. 
         [0212]    Actuator system  3400  includes an inner housing portion  3422 , slideably engaged within outer housing portion  3406 . Inner housing portion  3422  includes one or more detents, illustrated here as detents  3424  and  3426 , to lockingly engage one or more corresponding openings  3428  and  3430  in an inner surface of outer housing portion  3402 , as described below with respect to  FIG. 35 . 
         [0213]    Actuator system  3400  includes one or more frangible snaps  3432  coupled, directly or indirectly, to inner housing portion  3422 . Frangible snap  3432  includes a locking detent  3434 , and member  3420  includes a corresponding locking detent  3436  to releasably couple member  3420  to frangible snap  3432 . 
         [0214]    Operation of actuator system  3400  is described below with respect to  FIGS. 35 and 36 . 
         [0215]      FIG. 35  is cross-sectional view of actuator system  3400 , wherein inner housing detents  3424  and  3426  are lockingly engaged with outer housing openings  3428  and  3430 . This configuration may be achieved by sliding or compressing inner housing portion  3422  and outer portion  3406  towards one another. In the configuration of  FIG. 35 , spring  3414  is in a compressed position, and has potential energy to cause a fluid controller system associated with member  3420  to move as described in examples above. In this configuration, button  3402  is proximate to frangible snap  3432 , while frangible snap detent  3434  and member locking detent  3436  remain engaged with one another to preclude member  3420  from moving in response to the potential energy of compressed spring  3414 . Inner housing detents  3424  and  3426  remain lockingly engaged with outer housing openings  3428  and  3430  to preclude inner housing portion  3422  and outer housing portion  3406  from moving apart from one another in response to the potential energy of compressed spring  3414 . 
         [0216]      FIG. 36  is cross-sectional view of actuator system  3400 , wherein button  3402  is pressed with sufficient force to move detent  3412  past frangible wall  3408 , and to cause button  3402  to spread frangible snap  3432 . Upon spreading of frangible snap  3432 , frangible snap detent  3434  and member locking detent  3436  disengage from one another, to allow the potential force of compressed spring  3424  to act on member  3420 . 
         [0217]    Actuator system  3400  may be implemented within assay system  300  in  FIG. 3 , as described below with respect to  FIGS. 37 and 38 . 
         [0218]      FIG. 37  is a perspective view of an assay system  3700 , including an outer housing portion  3702  and an inner housing portion  3704 , illustrated here in a first position relative to one another. Outer housing portion  3702  may correspond to outer housing portion  3406  ( FIGS. 34-36 ), and inner housing portion  3704  may correspond to inner housing portion  3422 . Assay system  3700  further includes an actuator button  3712  and an opening  3714 , which may correspond to button  3402  and opening  3428 , respectively, in  FIGS. 34-36 . 
         [0219]      FIG. 38  is another perspective view of assay system  3700 , wherein outer housing portion  3702  and inner housing portion  3704  are illustrated in a second position relative to one another, which may correspond to  FIG. 35  or  36 . 
         [0220]    Assay system  3700  further includes a sample chamber  3706 , a sample chamber lid hingedly connected to inner housing portion  3704  to enclose and seal sample chamber  3706 , and a display window  3710 . 
         [0221]    Assay system  3700  may include assay system  2200  ( FIGS. 22-27 ), wherein inner housing portion  3704  correlates to housing portion  2202 , sample chamber  3706  correlates to sample chamber  2216 , and display window  3710  correlates to display window  2232 . 
         [0222]    Similarly, assay system  3700  may include assay system  2800  ( FIGS. 28-33 ), wherein inner housing portion  3704  correlates to housing portion  2802 , sample chamber  3706  correlates to sample chamber  2816 , and display window  3710  correlates to display window  2832 . 
         [0223]    Similarly, assay system  3700  may include one or more pumps  600 ,  900 ,  1100 ,  1500 ,  1800 ,  2100 . 
         [0224]    A user-initiated actuator may be configured to individually control multiple sets of one or more plungers or fluid controllers.  FIG. 39  is a cross-sectional diagram of a portion of an assay system  3900 , including a plurality of control rods, or stems  3910   a - 3910   c,  to individually control, through pushing and/or pulling, a plurality of sets of one or more plungers or fluid controllers, in response to corresponding forces from a user-initiated actuator. 
         [0225]    One or more stems  3910  may be coupled to a plurality of adjacent and/or non-adjacent plungers. Stems  3910  may be individually controllable to exert a force, push and/or pull, on respective plungers. 
         [0226]    One or more of stems  3910  may be telescoped inside another one of stems  3910 , as illustrated in  FIG. 40 . One or more of stems  3910  may be implemented as individual stems  3910 , as illustrated in  FIG. 41 . 
         [0227]      FIG. 21  is a cross-sectional block diagram of a portion of an assay system  2100 , including a user-initiated actuator  2104 , and one or more fluid passages  2110  within a housing  2102 , between user-initiated actuator  2104  and one or more fluid chambers. User-initiated actuator  2104  may include a combination of chemicals, separated by a user-rupturable membrane, within a flexible tear-resistant membrane  2106 , which, when combined, create a pressurized fluid, as is well known. The pressurized fluid may be gas or liquid. The pressurized fluid causes fluid controllers  2112  to move as described in one or more examples above. Multiple user-rupturable membranes may be implemented for multiple fluid passages  2110 .