Patent Publication Number: US-2021162415-A1

Title: A novel rapid individualized whole blood chip for antibiotic, drug, and food allergies

Description:
FIELD OF THE INVENTION 
     The present invention relates to ex vivo diagnostics of allergies to, for example, foods and drugs. 
     BACKGROUND OF THE INVENTION 
     Antibiotic allergies make up 19-30% of all adverse drug reactions and are common among adults and children. In clinical practice, when antibiotic allergies are not identified, patients may suffer from severe and potentially life-threatening reactions to the antibiotic. Conversely, many patients are labeled with antibiotic allergies in their medical records that are found to be clinically insignificant upon further resting. For example, penicillin allergies are reported in 8% of patient records in the U.S. However, some of these individuals are not truly allergic and can receive penicillin safely. Patients who are misdiagnosed with an antibiotic allergy are frequently treated with alternate antibiotics that are more toxic, less effective, susceptible to resistance, and more expensive. 
     Unverifiable antibiotic allergy is a growing problem in healthcare and the cost associated with antibiotic-related adverse events in the clinic is an estimated $40 billion annually. Diagnostic tools for rapid and accurate screening of patient antibiotic sensitivity are critical for clinical practice. However, the current diagnostic methods for the evaluation of allergies are severely limited in their use. The sensitivities and specificities of the available tests are variable and many methods are cumbersome due to the need for expensive equipment and long result times. 
     Presently, in vivo methods such as scratch, puncture, and prick tests (epicutaneous), intradermal testing (intracutaneous), and patch testing require patient exposure to the allergen and could potentially cause morbidity or mortality due to reactions such as anaphylaxis (Ariza, Fernandez, Mayorga, Blanca, &amp; Torres, 2013; Boyce et al., 2010). In vitro tests include techniques for testing blood for the presence of specific IgE antibodies to particular antigens, the Basophil Activation test (BAT), and the Antigen Leukocyte Cellular Antibody (ALCAT) automated food allergy test (“BlueCross BlueShield of North Carolina Corporate Medical Policy: Allergy Testing,” 2015; PJ Fell PJ, 1988; “PRE-PEN (benzylpenicilloyl plylysine injection USP) Skin Test Antigen,” 2015; Solensky &amp; Khan, 2014; Song et al). However, these tests often lack sufficient sensitivity and specificity for reliable clinical utilization for ex vivo allergen diagnosis or allergy severity prognosis. For food allergies, the double-blind, placebo-controlled food challenge (DBPCFC) is the gold standard but is must be performed by an allergist, can only be utilized for food allergies, and has the potential to cause a life-threatening anaphylactic reaction. 
     PRE-PEN® (benzylpenicilloyl polylysine injection USP), the major penicillin allergen determinant, is the only FDA-approved skin test for the diagnosis of penicillin allergy. PRE-PEN® is administered through both scratch and intradermal testing. Unfortunately, the test has significant limitations including subjective readout and the requirement of a trained physician or immunologist to interpret the results. Testing with PRE-PEN alone reportedly identifies up to 90% of patients likely to have immunoglobulin E (IgE)-mediated reactions to penicillin and potentially misses at least 10% that would be caused by the minor determinants penicillin G (benzylpenicillin), penicilloate, and penilloate. No other clinically used drug or antibiotic allergy diagnostic tests are available (“PRE-PEN (benzylpenicilloyl plylysine injection USP) Skin Test Antigen,” 2015; Selimović, Jia, &amp; Fraden, 2009; Solensky, 2003). In addition, there is wide acceptance that IgE is necessary but not sufficient for acute allergic reactions. Some co-factors are known, but many have yet to be tested. 
     Thus, there is clearly a strong need to develop a novel diagnostic tool for reliable and timely diagnosis of allergies to substances such as antibiotics, drugs, and foods. 
     SUMMARY OF THE INVENTION 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject. 
     The present invention relates to a microfluidic chip and proprietary cellular-based immunological algorithm capable of detecting an immunological response to foods, antibiotics, and/or other drugs simultaneously via several biomarkers, and in a single analysis step. This new diagnostic method will detect the presence of an allergic response and predict the severity of the allergy in individuals of any background. The method relies on biomarkers produced by cellular components of whole blood ex vivo, utilizing microfluidic technology described herein after exposure of an individual&#39;s blood to allergens (food, antibiotics, and/or other drugs). 
     In a preferred embodiment, the present invention further comprises a novel combination of whole blood and serum biochemical markers that—when combined together in a weighted mathematical prospective algorithm—will be suited for highly sensitive and specific diagnosis of antigen allergy ex vivo. The algorithm markers include interleukin (IL)-2, IL-4, IL-13, tryptase, histamine, and leukotriene C4 (LTC4), as well as allergen-specific IgEs and IgGs when appropriate. The readout will be generated from these markers weighted with appropriate coefficients or via deep learning algorithms. 
     The invention described herein enables an allergy test to be fully conducted ex vivo, only requires a blood draw, finger prick, or collection of other biological samples, and has the benefit of not requiring oral or dermal administration of the allergen to a test subject/patient. 
     Additionally, the invention is capable of simultaneously testing a patient&#39;s response to one or multiple allergens. Examples include multiple antibiotics, one or several other drugs, and/or one or multiple food allergens and at a single concentration or at multiple concentrations. Preferably, each test can be conducted in triplicate on the same chip and at the same time to improve the accuracy of the read-out. Accuracy could be further improved by including positive and/or negative controls at the same time. 
     In a preferred embodiment, the test analyzes the presence and quantity of several biomarkers as a result of the patient&#39;s blood sample mixing with an antibiotic, thereby creating a clear profile of the allergic response. For example, the detection of the increased presence of only one biomarker may not be sufficient to indicate hypersensitivity to a drug, but the detection of increased levels of multiple biomarkers may be sufficient. The chip provides a clear readout of the various biomarkers within 4 to 6 hours (for the type I hypersensitivity test); alternatively, a modified version of the chip will provide a readout of the biomarkers within about 96 hours (for the type IV hypersensitivity test). 
     The chip of the present invention also has the benefit of not requiring an allergist or trained physician for operation or readout. Only standard laboratory staff or medical personnel at a doctor&#39;s office or in a hospital will be necessary. Additional benefits of using the described microfluidic device include low reagent volumes (which in this case refers to enzyme-based assay reagents, food and/or drug samples, and the blood sample), the ability to detect minute amounts of biomarkers that could not be adequately quantified utilizing prior technology, and fast processing due to the relatively short diffusion times of reagents on-chip. The present invention relates to an incubation chamber comprising an inlet, an outlet, and a vertical fluidic barrier, wherein said fluidic barrier blocks the diffusion of particles in a solution of 0.1-20 microns in size. 
     In preferred embodiments, the solution can be a biological solution, a wash solution, a nutrient solution, and/or a solution of beads. Examples of such biological solutions include, but are not limited to, a blood sample, a serum sample, a plasma sample, a urine sample, a fecal sample, a saliva sample, a cerebrospinal fluid (CSF) sample, a bone marrow aspirate sample, and/or a vitreous sample. 
     Particles in the solution that can be processed and detected include, but are not limited to an antigen, an antibody, capture DNA, capture RNA, capture any protein of interest, and/or capture any particles of interest in the target solution 
     The fluidic barrier that is used in the incubation chamber includes a micro-pillar, a porous wall, a porous membrane, a hydrogel, micro/nano-grid, or a PVDF-PZT composite. Moreover, the fluidic barrier blocks the diffusion of particles of a size selected from: 0.1-20, 0.5 to 20 microns; 0.5 to 10 microns; 0.5 to 5 microns; 5 to 10 microns; 10 to 15 microns; 15 to 20 microns, or 0.1 to 6 microns. 
     In further preferred embodiments, the incubation chamber further comprises a channel. In preferred embodiments, the channel (a) comprises an outer channel separated from a center channel by the fluidic barrier and/or (b) is a concentric channel. The center channel can be; (a) positioned in between at least two outer channels; and/or (b) surrounded by outer channels. 
     In further preferred embodiments, the incubation chamber comprises multiple channels. Representative examples of the number of channels in the incubation chamber, include but are not limited to at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or 35 channels. In some preferred embodiments, some and/or even all of the multiple channels are (a) connected to one another; (b) positioned radially, semi-radially, or parallel to one another; and/or (c) at least two channels comprise fluidic barriers that block the diffusion of different sized particles. 
     The incubation chamber can also comprise multiple inlets and/or outlets, allowing for the addition and/or processing of multiple solutions, including multiple different solutions. 
     In further preferred embodiments, the channel width is between 1-500 microns in size, and even more preferably, between 50-500 microns in size. In other embodiments, the channel height is between 1-500 microns in size, and even more preferably, between 10-500 microns in size. 
     In additional preferred embodiments, the incubation chamber of can be created by placing a bi-well insert into a microwell, wherein the fluidic barrier is a porous membrane, porous wall, hydrogel, micro/nano-grid, or PVDF-PZT composite, and wherein the inlet and the outlet are the same. In preferred embodiments, this fluidic barrier of the microwell blocks the diffusion of particles of or 0.1 to 6 microns in size. 
     In further preferred embodiments, a biological sample can flow into at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30 or 35 chambers from each channel. In a further embodiment, each chamber comprises a different allergen. In further preferred embodiments, the allergen is selected from Table 1, and in even further preferred embodiments, at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65 different allergens are selected from Table 1. In some embodiments, the same allergen is included in three or four different chambers on the chip. As described herein, at least one chamber can comprise a marker used to detect pregnancy, to type blood, or to measure blood counts. 
     The microfluidic chip can comprise at least one channel and at least one chamber, wherein said chamber is connected to the channel so that a biological sample can flow from the channel to the chamber. 
     In other embodiments, the incubation chamber described above is integrated with a read-out chamber. Such readout chamber can comprise an inlet and an outlet connected to a channel, wherein said channel comprises a series of sequentially ordered seats having a concave shape with an opening and a separation between the base of the seats, wherein a fluid flowing through said channel exhibits a hydrodynamic resistance, wherein a hydrodynamic resistance ratio between the hydrodynamic resistance of the flow through the first empty seat (R 1 ) and the hydrodynamic resistance of the flow through the next empty seat (R 2 ) is from 1 to 3, wherein R 1  is smaller than R 2 . In some embodiments, the seats of the readout chamber (a) are evenly distributed; (b) comprises multiple rows of sequentially ordered seats. Such multiple rows can be separated by a flow guide structure. 
     The flow direction of the sample in the readout chamber can be (a) fixed; (b) dynamically changed; and/or (c) controlled by a valve. Such valve can be (a) intermittently switched to change the direction of R 2 ; (b) switched when the sample reaches a row&#39;s last sequentially ordered seat; (c) switched when the sample reaches the chamber&#39;s last sequentially ordered seat of all odd or even rows. 
     In other preferred embodiments, the readout chamber comprises (a) between 2-400 seats; (b) between 50-100 seats; (c) between 50-150 seats; (d) between 100-200 seats; (e) between 100-300 seats; (f) between 100-400 seats; or (g) more than 50, 100, 150, 200, 300, 400, 500, 600, 700, 800, 900 or 1000 seats. 
     Thus, incubation chamber as described above can be incorporated into a microfluidic chip and can also include the readout chamber as described herein. 
     The microfluidic chip can further comprise at least one antigen, and when multiple antigens are used, the antigens can be different. In preferred embodiments, the antigens are selected from Table 1, and can include at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65 different antigens are selected from Table 1. These antigens can be included in three or four different incubation chambers and can be the same or different. Moreover, the antigen can be bound to a microbead. The incubation chambers can also include markers, such as for example, a marker to detect/measure pregnancy, CBC measurements (such as for example white blood cell fractions (such as neutrophils, basophils, eosinophils); hemoglobin levels; platelet levels; human chorionic gonadotropin (hCG); blood serum or plasma viscosity; blood typing; serologic cross-matching; yeast; a primary cell; a cancer cell; stem cell; a differentiation factor; an antibody; an allergen; a drug; a substance used to monitor the change of signal, morphology, cytotoxicity or collecting secreting substance; static droplet arrays; and/or cell free tumor or viral DNA. 
     In further preferred embodiments, the microfluidic chip of the present invention can have a passive gradient generator so that the concentration gradient of a reagent can be established without a dilution process. In further preferred embodiments, the microfluidic chip of the present invention can generate a concentration gradient profile spanning several orders of magnitude. The concentration gradient profile can be adjusted by the geometrical design of the channels of the microfluidic chip based on hydraulic series resistance analysis. 
     In preferred embodiments, the microfluidic chip of present invention can comprise a polymer, glass, silicon, metal or combination thereof. Examples of such polymers include, but are not limited to (poly) dimethylsiloxane (PDMS), cyclic olefin copolymer (COC), polyethylene or teflon (PET), Mylar, or another polymer, hydrogel, glass, or metal. Additionally, the channel can comprise an empty structure with walls made of one of the above materials. 
     In a preferred embodiment, a kit can comprise the incubation chamber and/or a microfluidic chip comprising an incubation chamber of the present invention, and in further preferred embodiments, the kit can comprise a solution comprising an antibody capable of detecting an immune response. In further preferred embodiments, the antibody is capable of binding to a protein selected from: IgGs, IgEs, histamine, IL-2, IL-4, IL-13, tryptase, or LTC4. 
     The microfluidic chip or the kit can be used for the diagnosis of an allergic response and/or detect a biological substance in the biological sample. Examples of such substances that can be detected include, but are not limited to: (a) a cell, such as a WBC, (such as a neutrophil, a basophil, or an eosinophil); a platelet; a primary cell; a cancer cell; a stem cell; (b) a molecule, such as Hgb, a differentiation factor, an antibody, an allergen, a drug, human chorionic gonadotropin (hCG), IgGs, IgEs, histamine, IL-2, IL-4, IL-13, tryptase, or LTC4, or a substance used to monitor the change of signal, morphology, cytotoxicity, or levels of a secreted substance; (c) a microorganism, such as yeast; and/or (d) a droplet containing various physio-chemical and/or biological substances. By detecting these substances, one can for example, (a) diagnose an allergic response; (b) detect the substance; and/or (c) analyze or measure the reaction within or between droplets. 
     The present invention also relates to a method of diagnosing the potential for an allergic response in a patient that involves placing a biological sample obtained from the patient on the microfluidic chip, where it will come in contact with the antigen. The presence or absence of an immune response will then be measured. 
     In a preferred embodiment, the biological sample is selected from blood, saliva, or urine. In a further preferred embodiment, the method comprises adding a solution containing an antibody capable of detecting an immune response by binding proteins such as IgGs, IgEs, histamine, IL-2, IL-4, IL-13, tryptase, or LTC4. The immune response can be measured by detection of fluorescence microscope, surface plasmon resonance, bead-based solid phase detection methodologies, or colorimetric absorbance methodologies. 
     In a preferred embodiment, the method of diagnosing the potential for an allergic response in a patient by using the test described herein has greater than 95%, 96%, 97% or 98% (preferably greater than 99%) sensitivity and/or specificity. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  shows the top view of the general structure of one exemplified chip, with black lines representing fluidic channels in the bottom layer and red lines representing fluidic channels in the top layer. The exemplified chip is divided into three sections such as an incubation chamber A, a washing chamber B, and a readout chamber C. The outlets of the first two chambers are connected to the inlet of the following chambers via a bridge  4 . 
         FIG. 2  shows a magnified sketch of the bottom layer of the incubation or washing chambers, which have identical structures. There is an outer channel  9  (cellular incubation channel) and a center channel  10  (microbead analyte capture channel). 
         FIG. 3  shows the magnified sketch of the top layer. There are holes in the ends of channels  6  and  7 , which connect to the center channels of the bottom layer. 
         FIG. 4  shows the bottom layer at higher magnification for further detail. 
         FIG. 5  shows a one-way readout chamber in which individual microbeads  11  are captured in evenly spaced seats. 
         FIG. 6  shows the principle of the one-way readout chamber. 
         FIG. 7  shows a one-way readout chamber fully filled with microbeads  11 . 
         FIG. 8  shows the embodiment of the two-way readout chamber. 
         FIG. 9  shows the valve position 15 for filling the even rows of a two-way readout chamber. 
         FIG. 10  shows a two-way readout chamber fully filled with microbeads. 
         FIG. 11  shows a schematic of an exemplified imaging setup, including the excitation light source (a red or UV light-emitting diode (LED)), the microfluidic chip on the robotic x-y-z stage, and the location of the camera. 
         FIG. 12  shows a photograph of an exemplified prototype of the microfluidic chip, made of PDMS (a). Magnified view of the incubation chamber shown in (b) and the readout chamber shown in (c). 
         FIG. 13  depicts an example of an individual microwell bi-well insert, which is comprised of a porous vertical fluidic barrier 16, cellular incubation chamber 17, and well access for the washing chamber 18. 
         FIG. 14  indicates bi-well insert placed into microplate 19. 
         FIG. 15  shows a whole microplate bi-well insert. 
         FIG. 16  depicts a microwell plate with built-in bi-well fluidic barrier 20. 
     
    
    
     DETAILED DESCRIPTION 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
     Before describing the present invention in detail, it is to be understood that this invention is not limited to particularly exemplified materials or process parameters as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only, and is not intended to be limiting of the use of alternative terminology to describe the present invention. 
     Definitions 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art, such as in the arts of peptide chemistry, cell culture and phage display, nucleic acid chemistry, and biochemistry. Standard techniques are used for molecular biology, genetic, and biochemical methods (see Sambrook et al., Molecular Cloning: A Laboratory Manual, 3rd ed., 2001, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.; Ausubel et al., Short Protocols in Molecular Biology (1999) 4th ed., John Wiley &amp; Sons, Inc.), which are incorporated herein by reference. 
     As used herein, “microfluidic chip” or “chip” is defined as a lab-on-a-chip that comprises at least one channel with an input and an output and at least one chamber that allows the loading of small volumes of biological samples or fluids. The chamber of the chip can be preloaded with any antigens, allergens, and biomarkers. Examples of microchips are described herein. 
     As used herein, a “microwell” is a chamber in a microtiter plate that is designed to hold liquid volumes between 10 microliters and 10 milliliters. A plate may contain 6, 12, 24, 48, 96, or 384 microwells. 
     As used herein, a “bi-well insert” is a structure comprising a porous vertical fluidic barrier that divides a microwell into two compartments that remain in contact through the aqueous phase, allowing diffusion of soluble molecules. As shown in  FIG. 13 , a bi-well insert comprises a vertical porous fluidic barrier 16, a cellular incubation chamber 17 containing an inlet, and a washing/capture chamber 18 also containing an inlet, wherein the inlet of the incubation chamber 17 and the washing/capture chamber 18 also functions as an outlet. In preferred embodiments, a bi-well insert can be individually made and “plugged” into a microwell (see, e.g.,  FIG. 14 ). In further preferred embodiments, multiple bi-well inserts integrate to form a whole plate insert which conveniently provides bi-wells for the entire plate (see, e.g.  FIG. 15-16 ). 
     As used herein, a “fluidic barrier” is defined as a structure that blocks particles (e.g., such as microbeads and red blood cells) of a desired size while allowing for the diffusion of smaller molecules. In preferred embodiments, a fluidic barrier comprises micro-pillars. The distance between the “micro-pillars” will determine the size cut-off for particles that can diffuse between the channels. Thus, the fluidic barrier provides fluidic resistance as well as a means of preventing the direct mixing of the sample and a target. Due to the fluidic resistance provided by the micro-pillar, the majority of fluid moves independently. Other similar structures such as porous membranes, porous walls, hydrogels, micro/nano-grids, or PVDF-PZT composite can substitute for the micro-pillar as long as they can provide similar functions. 
     As used herein, a “channel” is defined as a rectangular, circular, or tubular enclosed passage or conduit that allows fluidic substances to pass. As used herein, an “outer channel” is a channel that transports fluidic substances around another channel from which it is separated by pillars  8  or other fluidic barriers as shown in  FIG. 4 . As used herein, a “center channel” 10 is a channel that is surrounded by the outer channels  9  as shown in  FIG. 4 . As shown in  FIG. 4 , the channels may be arranged as concentric channels. 
     As used herein, an “inlet” and/or an “outlet” refers to a structure allowing the entrance and/or exit of fluidic substances. In some embodiments, the inlet and the outlet are the same. 
     As used herein, “chamber” is defined as an artificial reservoir or cavity where fluids are collected and stored for use. Assays are conducted in these chambers to determine the presence and amount of one or more biomarkers, e.g., biomarkers associated with an allergic response. As shown in the figures, an “incubation chamber” A is where physical and/or chemical reactions between substances occur and real-time analyte capture takes place. A “washing chamber” B is where microbeads are exposed to a fresh solution to remove unnecessary or unwanted materials from/around the microbeads. A “read-out” chamber C is where samples are arranged and organized to be investigated under an imaging setup. 
     As used herein, “bridge” refers to a channel, which connects the outlet of a chamber to the inlet of another chamber. 
     As used herein, a “seat” 13 is defined as a structure that can immobilize or trap an object as shown in  FIG. 6 . 
     As used herein, a “flow guide structure” 14 refers to an impenetrable barrier that determines the direction of flow as shown in  FIG. 6 . 
     As used herein, “(Poly) dimethylsiloxane”, abbreviated as PDMS, is defined as a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties. PDMS is optically clear, and, in general, inert, non-toxic, and non-flammable. It is also called dimethicone and is one of several types of silicone oil (polymerized siloxane). The chemical formula for PDMS is CH 3 [Si(CH 3 ) 2 O] n Si(CH 3 ) 3 , where n is the number of repeating monomer [SiO(CH 3 ) 2 ] units. 
     As used herein, “Polyethylene” (abbreviated PE) or polythene (IUPAC name polyethene or poly(methylene)) is defined as the most common plastic. Many kinds of polyethylene are known, with most having the chemical formula (C 2 H 4 ) n . Thus PE is usually a mixture of similar organic compounds that differ in terms of the value of n. 
     As used herein, “Teflon”, also called Polytetrafluoroethylene (PTFE), is defined as a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The best known brand name of PTFE-based formulas is Teflon by DuPont Co. 
     As used herein, “Cyclo olefin copolymer” (abbreviated COC), also called Cyclo olefin polymer (abbreviated COP), is defined as a polymer or mixture of polymers produced from a cyclic monomer or monomers. The best known brand name of COC is TOPAS Advanced Polymer&#39;s TOPAS. 
     As used herein, “Polyvinylidene fluoride—lead zirconate titanate composite” (abbreviated PVDF-PZT composite), is defined as a composite material that combines the excellent piezoelectric properties of ceramics with the flexibility and strength of polymers resulting in relatively high dielectric permittivity and breakdown strength. 
     As used herein, “Mylar”, also called BoPET (Biaxially-oriented polyethylene terephthalate), is defined as a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties, and electrical insulation. A variety of companies manufacture boPET and other polyester films under different brand names. In the UK and US, the most well-known trade names are Mylar, Melinex, and Hostaphan. 
     As used herein, “hydrodynamic resistance” is resistance against fluid flow. We use the analytical solution of Poiseuille flow in a rectangular channel to calculate the hydrodynamic resistance as shown below, where w is the width of the channel, h is the height of the channel, L is the length of the channel and μ is the fluid viscosity, 
     
       
         
           
             
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     As used herein, “static droplet arrays” are evenly spaced aqueous or oil droplets (Mashaghi et al. “ Droplet microfluidics: A tool for biology, chemistry and nanotechnology, TrAC Trends in Analytical Chemistry ”, Volume 82, 2016, Pages 118-125, Clausell-Tormos et al. “ Droplet - Based Microfluidic Platforms for the Encapsulation and Screening of Mammalian Cells and Multicellular Organisms ”, Chemistry &amp; Biology, Volume 15, Issue 5, 2008, Pages 427-437. 
     As used herein, “Deep learning” is one of machine learning methods based on information processing and communication patterns in a biological nervous system. The data representations needed for feature classification are discovered via training from structured, semi-structured or unstructured raw data. 
     As used herein “Image recognition” means to identify objects, features, or patterns from an image. 
     As used herein, “biological sample” refers to any specimen taken from a patient. The biological sample can include, for example, peripheral blood, stool, saliva, urine, bone marrow, and/or tissue from a surgical resection. In a preferred embodiment, the biological sample is a peripheral blood sample. It is understood that the biological sample reflects the immunological state of the patient, including various biomarkers for allergic, immunological, and other physiological states. 
     As used herein, “antigen” refers to any structural substance that, under appropriate conditions, induces a specific immune response and causes the immune system to produce antibodies. The antigen may originate from within the body or from the external environment such as chemicals, bacteria, viruses, and pollen. Antigen is recognized by highly variable antigen receptors such as B cell receptors or T cell receptors of the adaptive immune system. 
     As used herein, “allergen” is defined as a type of antigen, most often eaten or inhaled, that generates a hypersensitive immune response and causes an allergic reaction. An allergen is capable of stimulating a type-I hypersensitivity reaction through immunoglobulin E (IgE), a type of antibody normally used as a defense against parasitic infections. Allergens can be found in a wide range of environmental sources. Table 1 provides a non-exhaustive list of potential allergens that can be placed in a chamber of the present invention. 
     As used herein, “parallel”, in geometry, means two lines in a plane that do not intersect or touch each other at any point. 
     As used herein, “radially” refers to a series of lines that meet at a central point in a circle, cylinder, or sphere. 
     As used herein, “marker”, also used interchangeably with biomarker or biological marker, is defined as a measurable indicator of biological processes and biological states or conditions. 
     As used herein, “target,” is defined as a substance or cell of interest that can be detected and quantified. 
     As used herein, “blood typing” is defined as a method to classify the specific type of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells. The two most important human blood group systems are ABO (blood type A, B, O, or AB) and RhD antigen (positive, negative, or null). 
     As used herein, the term “serological cross-matching” refers to a method involving mixing of donor blood, serum, or plasma against recipient blood, serum, or plasma to evaluate for transfusion compatibility. 
     As used herein, the term “complete blood count” or “CBC” for short refers to a measure of the numbers of different types of blood cells in an individual&#39;s body. The measurement includes white blood cell count (WBC, leukocyte), white blood cell types (WBC differential), red blood cell count, hematocrit (HCT, packed cell volume, PCV), hemoglobin, red blood cell indices, platelet count, and mean platelet volume. 
     As used herein, “polymer” is defined as a macromolecule consisting of a large number of similar subunits bonded together. 
     As used herein, “hydrogel” is defined as a gel in which water is the dispersion medium. It is a network of hydrophilic polymer chains and is highly absorbent. 
     As used herein, “kit” refers to any collection of items or components needed for the use of the microfluidic chip. 
     As used herein, “solution” is defined as a homogeneous liquid mixture that contains two or more substances. 
     As used herein, “antibody” refers to immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e., molecules that contain an antigen binding site that immunospecifically binds peptide or protein. As such, the term antibody encompasses not only whole antibody molecules, but also antibody fragments as well as variants (including derivatives) of antibodies and antibody fragments. Examples of molecules that are described by the term “antibody” in this application include, but are not limited to: single chain Fvs (scFvs), Fab fragments, Fab′ fragments, F(ab′) 2 , disulfide linked Fvs (sdFvs), Fvs, and fragments comprising or alternatively consisting of, either a VL or a VH domain. The term “single chain Fv” or “scFv” as used herein refers to a polypeptide comprising a VL domain of an antibody linked to a VH domain of an antibody. 
     Additionally, antibodies of the invention include, but are not limited to, monoclonal, multi-specific, bi-specific, human, humanized, mouse, or chimeric antibodies, single chain antibodies, Fab fragments, F(ab′) fragments, anti-idiotypic (anti-Id) antibodies (including, e.g., anti-Id antibodies to antibodies of the invention), domain antibodies, and epitope-binding fragments of any of the above. The immunoglobulin molecules of the invention can be of any class (e.g., IgG, IgE, IgM, IgD, IgA and IgY) or subclass (e.g., IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) of immunoglobulin molecule. 
     As used herein, “immune response” is defined as the humoral immune response and/or the cell-mediated immune response to an antigen. In the humoral immune response, B lymphocytes produce antibodies that react with processed antigens. In the cell-mediated immune response, T lymphocytes activate macrophages and other immune cells in the presence of processed antigens. 
     As used herein, “allergic response” is defined as a hypersensitivity immune reaction triggered by substances (allergens) that are normally harmless or would only cause an immune response in certain individuals. Immunoglobulin E is produced in response to the presence of each allergen and causes cells to generate histamines and other substances that produce symptoms of allergic reactions. 
     As used herein, “fluorescent” refers to a substance that absorbs light and then re-emits it at the same or longer wavelength. Fluorescent substances can be conjugated to antibodies in order to enable detection of antibody binding. 
     As used herein, “surface plasmon resonance” refers to the resonant oscillation of conduction electrons at the interface between a negative and positive permittivity material stimulated by incidence light. A surface plasmon is an electro-magnetic wave propagating along the surface of a thin metal layer and the resonance conditions are influenced by the material adsorbed onto the thin metal film. The surface plasmon resonance is expressed in resonance units and is therefore a measure of mass concentration at the sensor chip surface. 
     As used herein, “colorimetric” refers to an assay in which a reagent undergoes a color change that indicates the presence of a substance of interest. As an example, an enzymatic colorimetric assay may involve an antibody linked to an enzyme that cleaves a substrate, leading to color change if the enzyme-linked antibody is present. 
     As used herein, “solid phase detection” refers to an assay in which one substance is immobilized through binding to a solid surface and then potential binding partners are added in the liquid phase. Binding can be detected through colorimetric or fluorescent detection as described above. 
     As used herein, “bead based detection” refers to an assay in which a substance is coupled to a bead and then exposed to potential binding partners. Again, detection of binding may be accomplished through fluorescent or colorimetric assays. 
     As used herein, “sensitivity” when used in the context of describing a test refers to the ability of the test to detect a person who has the quality or disease being interrogated by the test. The sensitivity can be described as the “true positive” rate of a test. For example, in the context of allergy, the sensitivity of a test refers to the probability of having a positive result in a person who has the allergy being tested. 
     As used herein, “specificity” when used in the context of describing a test refers to the ability of the test to correctly identify those who do not have the quality or disease being tested. The specificity is also described as the “true negative” rate of the test. 
     Table 1 provides a list of potential allergens that can be placed in a chamber of the present invention. Column 1 of Table 1 provides the common name of each allergen. Column 2 lists the species and Column 3 (IUIS Allergen) provides the systemic allergen nomenclature established by the World Health Organization and International Union of Immunological Societies (WHO/IUIS). Column 4 describes the type of allergen and Column 5 provides the structurally related allergens from different species within the same genus, or from closely related genera. Column 6 shows the protein length of the allergen and Column 7 correlates the GenBank Accession Number (“GI#”) with each allergen. Each allergen shown on Table 1 can be placed in a chamber on the chip of the present invention. Moreover, combinations of different allergens shown in each row of Table 1 can be included in different chambers on the chip of the present invention. The number of allergens that can be included in different chambers on a chip can vary depending on technical constraints, cost considerations, and/or the diagnosis being made. Thus in some embodiments, the chip can comprise at least 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 30, 31, 32, 33, 34, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 or more different allergens listed in each row of Table 1. Each chip can have different combinations of allergens, with each allergen being tested placed in different chambers on a single chip. 
     As used herein, the term “about” is used to refer to an amount that is approximately, nearly, almost, or in the vicinity of being equal to a stated amount, e.g., the state amount plus/minus about 5%, about 4%, about 3%, about 2%, or about 1%. 
     The term “patient” or “subject” as used herein in reference to individuals who are being tested for the potential to produce an allergic response to an allergen and can encompasses veterinary uses, such as, for example, the testing of a rodent (e.g. a guinea pig, a hamster, a rat, a mouse), rabbit, murine (e.g. a mouse), canine (e.g. a dog), feline (e.g. a cat), equine (e.g. a horse), bovine (e.g., cow) a primate, simian (e.g. a monkey or ape), a monkey (e.g. marmoset, baboon), an ape (e.g. gorilla, chimpanzee, orangutan, gibbon). In preferred embodiments the mammal is a human. 
     Other aspects and embodiments of the invention provide the aspects and embodiments described above with the term “comprising” replaced by the term “consisting of” and the aspects and embodiments described above with the term “comprising” replaced by the term “consisting essentially of”. 
     As used herein, “and/or” is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example “A and/or B” is to be taken as specific disclosure of each (i) A, (ii) B and (iii) A and B, just as if each is set out individually. 
     It is to be understood that the application discloses all combinations of any of the above aspects and embodiments described above with each other, unless the context demands otherwise. Similarly, the application discloses all combinations of the preferred and/or optional features either singly or together with any of the other aspects, unless the context demands otherwise. 
     The device of present invention is to derive simultaneous biological information on a variety of specific and nonspecific factors for risk of acute allergy from a single mammalian (including human) biological sample, such as a whole blood sample. In this situation, the blood sample will be acquired via a simple lancet skin pinprick or phlebotomy blood draw and analyzed by the microfluidic chip described herein, and the results will be integrated into a predictive algorithm that can accurately assess the current risk of acute allergic reactions to foods and/or drugs. 
     The chip can be employed in conjunction with antibodies specific for cell-derived biological markers including: total and allergen specific IgG &amp; IgE, histamine, cytokines such as IL-2, IL-4 and IL-13, tryptase, and LTC4. The antibodies can be conjugated with fluorescent dyes to produce a fluorescent signal upon binding to an antigen in the blood sample, or the antibodies can be detected in other ways, including surface plasmon resonance, bead-based solid phase detection, or colorimetric absorbance methodologies. 
     Utilizing this method, type I hypersensitivity reactions can be tested within 3 to 6 hours after the injection of the blood sample onto the chip and type IV hypersensitivity reactions within about 72-96 hours after the injection of the blood sample onto the microfluidic chip, with CO 2 , O 2 , and pH parameters regulated to match in vivo conditions and maintain cell viability. In preferred embodiments, the chip described herein will have greater than 99% sensitivity and specificity with our laboratory diagnostic solution, making this the gold standard for allergy diagnostics in the future—able to both diagnose allergies to antigens as well as possibly predict the severity of the allergic reaction. 
     As the technique and test will be conducted ex vivo, the patient will be protected from direct exposure to any allergens and the test will carry no risk of medical morbidity or mortality such as from anaphylaxis, making the test safe for all patients of all ages and for all allergy severities. 
     All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety for all purposes. 
     This invention includes technological steps to implement an incubation chamber and a readout chamber as shown in  FIG. 1 . The microbeads pretreated with different conditions fill the center channels  10  in the bottom layer of the first section A as shown in  FIG. 2  via the inlet  2  that leads the microbeads to the entrances  6  of the center channels  10  in the bottom layer. The blood sample fills the outer channel  9  of the first section A via the inlet  1 . The microbeads are incubated in the first section and moved to the next section B via the exits  7  that merge to the bridge  4  for washing. The washing solution is introduced to the outer channels to wash the microbeads by either continuous flow or pulsatile flow via the inlet  1  of the section B in the same manner as described for the section A. The blood samples are discarded via the exit  3  of the incubation chamber A. Once washing is finished, the microbeads  11  are moved to the inlet  12  of the readout chambers C where they are captured in the evenly spaced seats  13  for further signal analysis as shown  FIGS. 1, 5, and 6 . When the seats are evenly spaced, the inventors unexpectedly found that signal interference from overlapping or conglomerated beads is reduced, which is a typical issue of multiplexed readout methodologies. The washing solution is discarded via the outlet  3  of the washing chamber. The modular structure of these chambers allows additional units consisting of A, B, and C to be added for duplicate or triplicate on chip analysis. This allows potentially an unlimited number of allergens or conditions to be tested simultaneously on chip. 
     The outer channel  9  and the center channel  10  are separated by micro-pillars  8  as shown in  FIG. 4 , to prevent direct mixing of substances in the two channels but to allow mixing by diffusion. Due to this separation, the red blood cells and microbeads, for example, are not intermingled so that an additional extraction process of microbeads is unnecessary downstream. The microbeads can be either in the center channel  10  or outer channel  9  depending on the device configuration and application. 
     The readout chamber can have two different formats such as one-way chamber shown in  FIGS. 5, 6, 7  and two-way chamber shown in  FIGS. 8, 9, 10 . 
     A one-way readout chamber is composed of evenly spaced seats  13  and flow guides  14 . Because the shortest path to the outlet shown in  FIG. 5  is dependent on the location of the outlet  5 , the path toward left bottom has a smaller hydrodynamic resistance. 
     The principle of the one-way readout chamber is based on the hydrodynamic relationship between the seats  13 . The hydrodynamic resistance through the first empty seat R 1  is smaller than the hydrodynamic resistance through the second empty seat R 2  due the flow direction determined by the flow guide  14 . Thus, the next microbead will sit in the first empty seat. In this way, all empty seats will be taken in sequence automatically without missed microbeads as shown in  FIG. 7 . The hydrodynamic resistance makes sure the empty seat closest to the inlet will be taken first. 
     The two-way readout chamber is composed of evenly spaced seats  13  and a microvalve  15  instead of the flow guide. The microvalve  15  changes the flow direction dynamically so that the shortest path to the outlet  5  can be switched accordingly. The hydrodynamic relationship between the seats for the two-way readout chamber is same as that for the one-way readout chamber. Once the odd rows are filled, the microvalve  15  changes the flow direction to fill the even rows as shown in  FIG. 9 . 
     The bi-well insert, shown in  FIGS. 13, 14, 15, and 16  contains a porous vertical fluidic barrier. The insert maybe placed into a microwell in order to divide the well into two chambers. The fluidic barrier will prevent cells from crossing between the chambers while allowing diffusion of soluble molecules such as proteins. Preferably, the fluidic barrier pore size will be between 0.1 and 6 microns. 
     Examples 
     Example 1. Microfluidic Chip Material 
     The microfluidic chip will be fabricated from a polymer such as (poly)dimethylsiloxane (PDMS) and glass, although we will consider using COC or PTE film instead of PDMS and glass to reduce the cost of material for mass production. All fluidic channels will be embedded into the PDMS material via common soft lithography manufacturing processes (e.g. according to the previously published protocol (Selimović et al., 2009). 
     Example 2. Microfluidic Chip Fabrication and Structure 
     The following description is one of multiple possible chip designs. This description is only included for context, to visualize how the fluids (sample, reagents, and microbeads) will be routed on-chip and how the output (presence or absence of an immunological reaction) will be read out. 
     The chip will be created by molding it to photoresist patterns on silicon wafers. The device will then be assembled from three adjacent fluidic layers: two fluidic (channel/chamber) layers and one control layer, such that the channel layers guides fluids (blood) to the assay chambers (where reactions of interest take place), and microvalves on the control layer can be activated to close off all chambers from the fluidic channels. (The rough fabrication protocol for such microvalves can be found in Selimović et al., 2009).  FIG. 4  shows the magnified view of a part of the chip. For simplicity, the control layer is not shown. 
     The drawing in  FIG. 4  also shows the micro-pillars as part of the incubation chamber, preventing direct mixing of substances in the two channels. The assembled microfluidic chip can be bonded to a sticky PET film or to a glass slide for stability and to avoid drying out of the device, since water that is present in the blood sample can permeate the PDMS layer. Alternatively, the bottom layer in  FIG. 1  can also be made of glass. The choice of material for the bottom layer of the device has no bearing on the function and accuracy of the microfluidic chip. 
     The following description only serves to explain the function and operation of the chip, with the understanding that a variety of channel and assay chamber dimensions on the microscale (below about 1000 micrometers, below about 900 micrometers, below about 800 micrometers, below about 700 micrometers, below about 600 micrometers, below about 500 micrometers, below about 400 micrometers, below about 300 micrometers, below about 200 micrometers, below about 100 micrometers, below about 50 micrometers, below about 10 micrometers, and/or below about 5 micrometers) can be used. The channels will have a low height compared to the width; at such aspect ratios the channels can easily be closed by a microvalve (on the control layer) activated at 20 psi or less. 
     There is no limit on the maximum chamber size, as long as the following factors are considered: minimizing the reagent volume, minimizing the sample volume (blood), keeping the device confined to a size comparable to a 2″×3″ glass slide, so that it can be conveniently held in the hand during the blood collection from a finger prick, and keeping the aspect ratio of all features such that common (soft) lithography techniques can be used. Thus, chamber widths of up to 1000 micrometers can be used. 
     Example 3. On Chip Treatment of the Microbeads with Antibodies 
     Instead of using pretreated microbeads, the microbeads can be pretreated on chip by adding a treatment section before the first section A shown in  FIG. 1 . 
     Example 4. Adding the Sample onto the Chip 
     In one embodiment, the chip is delivered to the user with all allergens (food particles, drugs, and/or antibiotics) loaded onto the chip in a dry state and additional reagents will be added in an automated format. Alternatively, the additional reagents may be prepackaged on the chip as well. All incubation chambers will contain the same amount of antibiotic or other allergen at this stage. Assuming that the largest incubation chamber has a volume on the order of 10 nl, the total amount of blood necessary to run a single chip will be on the order of 1 microliter. A finger prick can provide a blood sample on the order of 50 microliters, while several milliliters of blood can be collected by drawing blood with a needle. Thus, both blood collection methods can supply enough blood for a single chip. 
     When whole blood is utilized, the chip will contain lithium heparin or another anticoagulant that will mix with the patient&#39;s blood sample upon collection to prevent the blood from coagulating. Then, the mixed solution can be loaded onto the chip (Inlets for blood 1) either by using a hand-held plastic syringe (or a syringe pump) or via capillary flow of the blood from the finger stick. We envision applying only relatively low flow rates to distribute various fluids throughout the chip, so that only low pressures will be built up inside the microfluidic channels. To fully avoid building up pressure inside the chip, the liquids can be pulled through the chip (by applying negative pressure at any outlets ( 3 ,  5 ) instead of pushing the liquids (e.g. by using a pipette to introduce the blood sample into the chip). As the blood/coagulant solution flows into the microfluidic chip, it will displace any air previously present inside the fluidic channels and incubation chambers. When it reaches the incubation chambers, it will dissolve the dry drug/antibiotic or suspend the food allergens. The flow of the solution will be sufficiently slow to not flush the allergens from the chamber. 
     The blood can be introduced through the inlet for blood 1 such that it reaches the outer channels  9 . After enough incubation time, the solution or microbeads move to the next section and the blood exits through the outlet  3  and can be collected inside attached polyethylene tubing or simply allowed to collect on top of the ports and evaporate there. 
     Example 5. On-Chip Tests 
     Preferably, each chip can provide a positive and a negative control, conducted, for example, in triplicate. For example, the chip can enable the simultaneous testing of up to 5 different allergens and 2 controls, each of those by analyzing the presence of at least 5 biomarkers in the blood, and each experiment being repeated in triplicate, the total number of assays conducted on the chip can be 105. Since in this example all incubation chambers are connected with channels only in one direction, the blood or coagulation solution flowing through one particular channel will only reach one particular allergen and only one particular set of antibodies and will not mix with other allergens or have access to other antibodies. In addition, each chip is a preferably single-use device to avoid cross-contamination and will be disposed of appropriately after the test is completed. 
     In addition to allergy testing, other testing that could be performed on the microchips includes measuring blood counts, blood typing, and blood cross-matching. Blood typing could be performed by mixing the sample with antibodies against various blood groups and monitoring for an agglutination (clumping) reaction. Blood cross-matching could be performed by mixing an individual&#39;s blood with blood from one or more individuals to evaluate for agglutination or hemolysis. 
     Example 6. Analyzing the Sample 
     Any required washing steps or introduction of additional reagents for enzyme-based assays will rely on injection of those solutions through the inlet of the second section B in  FIG. 1 . 
     As part of the reaction between blood components and the allergens, particular biomarkers expressed in the blood will bind to the antibodies on the microbeads or surface of the incubation chamber. Washing steps will remove any unbound biomarkers and the allergen. Additional antibodies that bind to the marker of interest will then be introduced, and detection will be accomplished via fluorescence or colorimetric read-outs (depending on the substance conjugated to the detection antibodies). Hence, the reaction will have to occur in a dark chamber to avoid any potential bleaching effects. Each individual readout chamber can be evaluated under a fluorescence microscope or with a spectrophotometer to detect the presence or absence of bound biomarkers. 
     Example 7. Result Readout 
     If a fluorescence microscope is used, a light-emitting diode (LED) will be used as an excitation source. We plan to employ UV, red, and other LEDs to excite the fluorophores conjugated to the antibodies (Randers-Eichhorn, Albano, Sipior, Bentley, &amp; Rao, 1997).  FIG. 11  details a possible imaging setup with the chip placed on a robotic xyz stage and underneath an objective. The camera can either be a CCD chip camera, or depending on the required resolution, a camera attached to a common smartphone, or a web-camera via an adapter. The camera will record the resulting fluorescence signals and save the data as image files. A proprietary algorithm (loaded as a mobile application onto a smartphone or a computer, for example) will then measure the intensity of the signal in each assay chamber and report those numbers to conclude whether an allergic reaction is present. 
     An alternative to this optical read-out is presented by Chen et al., 2015. In this case, it is contemplated to pattern gold nanorods on the surface of all assay chambers and conjugate them with antibodies against the various antigens that are being interrogated. Data will be collected using localized surface plasmon resonance and the scattering intensity from the nanorods will be recorded for a sample in which no antigens are present and will be compared to the scattering intensity in our tests. The resulting spectrum shift will be used as a measure of an allergic reaction. 
     Example 8. Bead-Based Incubation Chamber 
     The incubation chamber described as the first section of the device (A) can be used for incubation of red blood cells with pretreated microbeads by introducing the red blood cells into the outer channel and the microbeads into the center channel or vice versa. 
     The incubation chamber described as the first section of the device (A) can also be used for incubation of antibody, allergen, or other substances to treat microbeads by introducing the substance into the outer channel and the microbeads into the center channel or vice versa. 
     The incubation chamber described as the first section of the device (A) can also be used for incubation of microdrops with other substances by introducing the microdrops into the outer channel and the substances into the center channel or vice versa. 
     The incubation chamber described as the first section of the device (A) can also be used for incubation of two or more substances by introducing the one substance into the outer channel and the second substance into the center channel or vice versa. 
     The incubation chamber described as the first section of the device (A) can also be used for incubation of two or more cells by introducing one group of cells into the outer channel and another group of cells into the center channel or vice versa. 
     The incubation chamber described as the first section of the device (A) can also be used to examine blood viscosity by adjusting the space between the micro-pillars and monitoring pressure profile while applying steady, impulse, pulsatile, or other forms of pressure input. 
     The incubation chamber described as the first section of the device (A) can also be utilized for blood typing and serologic cross-matching by utilizing agglutination as tracked by image recognition paired with deep learning. 
     The incubation chamber described as the second section of the device (B) can be used for washing of the treated microbeads by introducing the washing solution into the outer channel and the microbeads into the center channel or vice versa. 
     Example 9. Bead-Based Readout Chamber 
     The seats in the readout chamber C separate beads and prevent bead overlap with even spacing. This allows discrete image processing via simple digital processing, and the accuracy of the readout result is greatly increased by avoiding noise and bias caused by bead overlap or close proximity, which is a typical issue of conventional multiplexed readout methodologies. 
     The readout chamber C can also be used to capture red blood cells for incubation or treatment with antibody, allergen, nutrients, or other substances. Substances secreted by the cells can be continuously collected. 
     The readout chamber C can also be used to capture microbeads for continuous treatment or reaction with antibody, allergen, or other substances while monitoring the change of signal. Because microbeads are monodispersed with a predetermined distance, quantitative analysis can be done without signal overlap 
     The readout chamber C can also be used to capture microdrops for continuous treatment or reaction with antibody, allergen, or other substances while monitoring the change of signal, size, color, or any other properties. 
     The readout chamber C can also be used to capture other cell types such as primary cells, cancer cells, or stem cells for applications such as identification of circulating tumor cells and culture, differentiation, or treatment with nutrients, differentiation factors, antibodies, allergens, drugs, or other substances. Changes in cell morphology, cytotoxicity, or levels of secreted substances can be measured. 
     The readout chamber C can also be used to capture yeast cells for culture, treatment or reaction with nutrients, antibodies, allergens, drugs, or other substances while keeping the first generation cells, monitoring offspring cells, and collecting secreted substances. 
     The readout chamber C can also be used to capture embryos or cloned embryos for culture, differentiation, treatment or reaction with nutrients, antibodies, allergens, drugs, or other substances while monitoring changes in cell morphology, cytotoxicity, or levels of secreted substances. 
     The readout chamber C can also be used to capture oocytes for in-vitro fertilization, culture, differentiation, treatment or reaction with sperm, nutrients, antibodies, allergens, drugs, or other substances while monitoring the changes in cell morphology, cytotoxicity, or levels of secreted substances. 
     The readout chamber C can also be used to capture small animals such as C-elegans for stimulation, treatment or reaction with nutrients, stimuli, antibodies, allergens, drugs, or other substances while monitoring for changes in morphology or levels of secreted substances 
     The readout chamber C can also be used to capture two different types of cells, oocytes, embryos, microbeads, droplets, or animals for co-culture, comparison, or other simultaneous study 
     The readout chamber C can also be used to measure cell density by counting the trapped cells. 
     The readout chamber C can also be used to separate cells based on size and stained color by adjusting the size and shape of the microseats and controlling the flow path. 
     The readout chamber can be used to capture single white blood cells in metaphase for karyotype analysis after appropriate treatment in the incubation A and wash B chambers. 
     The readout chamber can be used to capture white blood cell fractions (such as neutrophils, basophils, eosinophils, lymphocytes, and monocytes) to generate an automated differential with the aid of image recognition paired with deep learning. 
     Example 10. Fabrication and Usage of the Bi-Well Insert 
     Relying on the same fluid dynamics, the chip can be designed as microwells containing bi-well inserts. In this situation, the bi-well insert can be made of construction materials such as polystyrene, polycarbonate, COC, PTFE, and PDMS using injection molding, 3D printing, and other manufacturing processes. The vertical membrane can be attached to the bi-well insert by gluing or heat press. 
     In this case, the bi-well insert divides a microwell into two chambers as described above—an “incubation chamber” ( FIG. 13 , number  17 ) and a “washing/capture chamber” ( FIG. 13 , number  18 ), both chambers having an inlet which also functions as an outlet. 
     Once the bi-well insert is in place, microbeads are introduced in the microwell via the inlet of  18  into the washing/capture chamber and whole blood is filled into the incubation chamber via the inlet of  17 . After a suitable incubation period the bi-well insert is removed and microbeads remaining in the microwell get washed. 
     Microbeads will be transferred to the bead-based readout chamber described in example 9 or to a commercially-available multiplex bead analyzer.