METHODS, DEVICES, AND SYSTEMS FOR DETECTING TWO OR MORE ANALYTES WITHIN SMALL VOLUMES

Abstract

This document provides methods, devices, and systems for detecting the presence, absence, or amount of two or more analytes present within a small volume (e.g., less than 10 μL) of a sample (e.g., a blood sample) obtained from a mammal (e.g., a human such as a human neonate). For example, methods and materials for using plasma separation and multiplex analyte detection to detect two or more analytes (e.g., proteins, carbohydrates, lipids, nucleic acids, intact cells, intact viruses, intact microorganisms, and/or chemicals) within a small volume of a blood sample are provided.

Claims

1. A multiplexed analyte detection system comprising: (a) a sample inlet area for receiving a sample, (b) a channel fluidly connected to said inlet area via an inlet port and comprising: (i) two or more serial sample chambers, wherein each of said two or more serial sample chambers comprises in inflow valve and an outflow valve along said channel, wherein said inflow valves and said outflow valves of each of said two or more serial sample chambers are controlled via a first master valve actuator port, and (ii) a vacuum port configured to allow application of a negative pressure to said channel, (c) a filter located between said inlet area and said channel and configured to filter said sample to allow a component of said sample to enter said channel when said negative pressure is applied via said vacuum port, and (d) two or more reagent chambers, wherein each of said two or more reagent chambers comprises a reaction control valve and is fluidly connected to one of said two or more serial sample chambers when said reaction control valve is open, thereby forming a reaction chamber, and is not in fluid communication with said one of said two or more serial sample chambers when said reaction control valve is closed, wherein said reaction control valves of each of said two or more reagent chambers are controlled via a second master valve actuator port.

2. The system of claim 1, wherein said sample is whole blood.

3-10. (canceled)

11. The system of claim 1, wherein said vacuum port is located at the end of said channel.

12. The system of claim 1, wherein said system comprises a positive pressure channel comprising: (i) a positive pressure control valve, and (ii) a positive pressure port configured to allow application of a positive pressure to said positive pressure channel, wherein said positive pressure channel is fluidly connected to said channel when said positive pressure control valve is open and is not in fluid communication with said channel when said positive pressure control valve is closed.

13. The system of claim 12, wherein said positive pressure channel fluidly connects to said channel at a location located between said inlet port and said serial sample chambers.

14. The system of claim 13, wherein said channel comprises a serpentine path, and wherein said positive pressure channel fluidly connects to said channel at a location located between said inlet port and said serpentine path.

15. The system of claim 12, wherein said channel comprises a sample cutoff valve located between said inlet port and said positive pressure channel.

16. The system of claim 1, wherein said channel comprises a sample cutoff valve located between said inlet port and said serial sample chambers.

17. The system of claim 1, wherein said channel comprises a serpentine path.

18. The system of claim 1, wherein said filter is a plasma separation membrane.

19. The system of claim 1, wherein said component of said sample is plasma.

20-23. (canceled)

24. The system of claim 1, wherein said system comprises reagents for detecting a first analyte if present within a sample chamber, wherein said reagents are located within one of said reagent chambers.

25. The system of claim 24, wherein said first analyte is selected from the group consisting of glucose, bilirubin, an enzyme, a protein, a chemical molecule, and a carbohydrate.

26. The system of claim 24, wherein said system comprises reagents for detecting a second analyte if present within a sample chamber, wherein said reagents are located within a second one of said reagent chambers.

27. The system of claim 26, wherein said second analyte is different from said first analyte, and wherein said second analyte is selected from the group consisting of glucose, bilirubin, an enzyme, a protein, a chemical molecule, and a carbohydrate.

28-43. (canceled)

44. A method for detecting the presence, absence, or amount of two or more analytes in a sample, wherein said method comprising: (a) obtaining a multiplexed analyte detection system comprising: (a1) a sample inlet area for receiving said sample, (b1) a channel fluidly connected to said inlet area via an inlet port and comprising: (i) two or more serial sample chambers, wherein each of said two or more serial sample chambers comprises in inflow valve and an outflow valve along said channel, wherein said inflow valves and said outflow valves of each of said two or more serial sample chambers are controlled via a first master valve actuator port, and (ii) a vacuum port configured to allow application of a negative pressure to said channel, (c1) a filter located between said inlet area and said channel and configured to filter said sample to allow a component of said sample to enter said channel when said negative pressure is applied via said vacuum port, and (d1) two or more reagent chambers, wherein each of said two or more reagent chambers comprises a reaction control valve and is fluidly connected to one of said two or more serial sample chambers when said reaction control valve is open, thereby forming a reaction chamber, and is not in fluid communication with said one of said two or more serial sample chambers when said reaction control valve is closed, wherein said reaction control valves of each of said two or more reagent chambers are controlled via a second master valve actuator port, (b) inserting from about 1 μL to about 10 μL of a sample into said sample inlet area, (c) applying negative pressure to said channel via said vacuum port, wherein said component of said sample is drawn into said two or more sample chambers, (d) actuating said first master valve actuator port to close said inflow valves and said outflow valves, (e) actuating said second master valve actuator port to open said reaction valves of each of said two or more reagent chambers, thereby allowing each reaction chamber to form, wherein the reagents of each of said two or more reagent chambers and said component of said sample of each of said two or more sample chambers within each formed reaction chamber mix to form a reaction mixture, and (f) detecting the presence, absence, or amount of analyte within each reaction mixture.

45. The method of claim 44, wherein said method comprising detecting the amount of an analyte using a colorimetric assay for at least one of said reaction mixtures.

46. The method of claim 44, wherein said method comprising detecting the amount of an analyte using a fluorescent-based assay for at least one of said reaction mixtures.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic of a microfluidic device for plasma separation and analysis according to some embodiments.

[0009] FIG. 2 is a schematic of a plasma separation system of a microfluidic device using a plasma separation membrane and 5 μL of blood according to some embodiments.

[0010] FIG. 3 is a bar graph comparing plasma separation achieved using a plasma separation system provided herein to plasma separation using a centrifugation method.

[0011] Similar results were achieved with both approaches as assessed measuring diluted bilirubin (D Bili), total bilirubin (T Bili), hemoglobin, and proteins.

[0012] FIG. 4 contains four images showing the mixture of food dyes. A yellow food dye was used to represent samples, and a blue food dye was used to represent assay reagents. A green color demonstrates effective mixing.

[0013] FIGS. 5A and 5B show results for reactions using the indicated amounts of D-glucose in a colorimetric assay (FIG. 5A) and the indicated amounts of LDH in a fluorescence-based assay.

[0014] FIG. 6 shows results for measuring glucose in plasma separated from 5 μL of whole blood using a microfluidic device provided herein. PBS was used as a negative control, and a glucose solution (8 mM) was used as a positive control.

DETAILED DESCRIPTION

[0015] This document provides methods, devices, and systems for detecting the presence, absence, or amount of two or more analytes present within a small volume (e.g., less than 10 μL) of a sample (e.g., a blood sample) obtained from a mammal (e.g., a human such as a human neonate). For example, this document provides methods and materials for using plasma separation and multiplex analyte detection to detect two or more analytes (e.g., proteins, carbohydrates, lipids, nucleic acids, intact cells, intact viruses, intact microorganisms, and/or chemicals) within a small volume of a blood sample.

[0016] Any appropriate type of analytes can be detected using the methods and materials provided herein. For example, a device or system provided herein can be configured to detect the presence, absence, or amount of a protein, carbohydrate, lipid, nucleic acid, intact cell, intact virus, intact microorganism, and/or chemical. Examples of proteins that can be detected using the methods and materials provided herein include, without limitation, enzymes such as lactate dehydrogenase (LDH), alanine transaminase (ALT), aspartate transaminase (AST), creatine phosphokinase (CPK), and metalloproteases (e.g., ADAM12), receptors such as soluble chemokine receptors (e.g., CCRS and CXCR4), soluble growth factor receptors (e.g., EGFR), and soluble transferrin receptor, serum proteins such as albumin, transferrin, alpha-1 anti-trypsin, and immunoglobulins, inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2), and interferon gamma (IFN-γ), viral proteins such as HIV envelope protein gp120 and E protein of SARS-CoV-2, bacterial proteins such as Mycobacterium tuberculosis surface protein Rv0227c and the MSCRAMM family of S. aureus, and fungal proteins such as Ssp1 and Sel1. Examples of carbohydrates that can be detected using the methods and materials provided herein include, without limitation, glucose, lactate, pyruvate, prostate-specific antigen (PSA), CA 125, and CA 19-9. Examples of lipids that can be detected using the methods and materials provided herein include, without limitation, total cholesterol, triglycerides, high density lipoprotein (HDL), and low density lipoprotein (LDL). Examples of intact viruses that can be detected using the methods and materials provided herein include, without limitation, human immunodeficiency viruses (e.g., HIV1 and HIV2), coronaviruses (e.g., COVID-19), Zika viruses, influenza viruses A and B, adenoviruses, RSV viruses, parainfluenza viruses, human metapneumoviruses, rhinoviruses, enteroviruses, hepatitis A, B, C and E viruses, rotaviruses, human papillomaviruses, measles viruses, caliciviruses, astroviruses, West Nile viruses, Ebola viruses, Dengue fever viruses, African swine fever viruses, herpes simplex viruses (e.g., HSV-2), Norwalk and Norwalk-like viruses, enteric adenoviruses, yellow fever viruses, chikungunya viruses, Epstein-Barr viruses, parvoviruses, varicella zoster viruses, and Ross River viruses. Examples of intact microorganisms that can be detected using the methods and materials provided herein include, without limitation, bacterial microorganisms such as Staphylococcus aureus (e.g., MRSA and MSSA), Streptococcus pyogenes, Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydia pneumoniae, Bordelella pertussis, Mycobacterium tuberculosis, E. coli (e.g., enterohaemorrhagic E. coli such as O157:H7 E. coli or enteropathogenic E. coli), Salmonella species (e.g., Salmonella enterica), Listeria monocytogenes, Acinetobacter baumanni, Klebsiella oxytoca, Sarcoptes scabiei, Neisseria gonorrhoeae, Chlamydia trachomatis, Treponema pallidum, Campylobacter species (e.g., thermophylic strains of Campylobacter jejuni, C. lari, or C. coli), Bacillus cereus, Vibrio species, Yersinia enterocolitica, Shigella species, Enterococcus species (e.g., Enterococcus faecalis or E. faecium), Helicobacter pylori, and Clostridium species (e.g., Clostridium botulinum or Clostridium perfringens), fungal microorganisms such as Aspergillus species (e.g., A. flavus, A. fumigatus, and A. niger), yeast (e.g., Candida norvegensis and C. albicans), Penicillium species, Rhizopus species, and Alternaria species, and protozoan microorganisms such as Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii. Examples of chemicals that can be detected using the methods and materials provided herein include, without limitation, bilirubin, parathyroid hormone, bile acid, and urea.

[0017] Any appropriate sample can be assessed (e.g., for the presence, absence, or amount of one or more analytes) using the methods and materials (e.g., devices and systems) provided herein. In some cases, a sample can be a biological sample. For example, a sample can contain whole cells, cellular fragments, DNA, RNA, carbohydrates, lipids, viruses, microorganisms, and/or proteins. Examples of samples that can be used in the methods, devices, and systems described herein include, without limitation, whole blood samples, serum samples, plasma samples, urine samples, saliva samples, mucus samples, sputum samples, bronchial lavage samples, fecal samples, buccal samples, nasal samples, amniotic fluid samples, cerebrospinal fluid samples, synovial fluid samples, pleural fluid samples, pericardial fluid samples, peritoneal fluid samples, urethral samples, cervical samples, genital sore samples, hair samples, and skin samples.

[0018] In some cases, a sample to be assessed (e.g., for the presence, absence, or amount of one or more analytes) using the methods and materials (e.g., devices and systems) provided herein can be an environmental sample, a water sample, a soil sample, a food sample, a meat sample, a produce sample, a drink sample, a plant sample, a leaf sample, a root sample, a flower sample, a stem sample, a pollen sample, a seed sample, or an industrial sample (e.g., an air filter sample, sample collected from a work station, or a sample collected from a storage facility).

[0019] In some cases, the devices and systems provided herein can retain the sample within the device for safe and clean disposal.

[0020] A sample to be assessed (e.g., for the presence, absence, or amount of one or more analytes) using the methods and materials (e.g., devices and systems) provided herein can be obtained using any appropriate technique. For example, biological samples can be obtained using non-invasive (e.g., swab) techniques or invasive techniques (e.g., venipuncture, finger stick, or biopsy). In some cases, a whole blood sample can be obtained from a human (e.g., a human neonate) using a glass capillary tube. For example, an environmental sample and/or an industrial sample can be obtained using a surface swab technique. In some cases, a sample can be a liquid sample.

[0021] A liquid sample can be any appropriate volume. As described herein, very small volumes of a sample can be collected and accurately analyzed for the presence, absence, or amount of two or more analytes using the methods and materials provided herein. For example, a liquid sample (e.g., a whole blood sample) with a volume of about 1 μL to about 10 μL (e.g., from 1 μL to 10 μL, from 2 μL to 10 μL, from 3 μL to 10 μL, from 4 μL to 10 μL, from 1 μL to 9 μL, from 1 μL to 8 μL, from 1 μL to 7 μL, from 1 μL to 6 μL, from 2 μL to 8 μL, from 3 μL to 7 μL, or from 4 μL to 6 μL) can be obtained and analyzed for the presence, absence, or amount of two or more analytes using the methods and materials provided herein. In some cases, a larger volume can be obtained from the source, and a small portion (e.g., a volume from 1 μL to 10 μL, from 2 μL to 10 μL, from 3 μL to 10 μL, from 4 μL to 10 μL, from 1 μL to 9 μL, from 1 μL to 8 μL, from 1 μL to 7 μL, from 1 μL to 6 μL, from 2 μL to 8 μL, from 3 μL to 7 μL, or from 4 μL to 6 μL) of that larger obtained volume can be used in the methods and materials (e.g., device or system) described herein.

[0022] A sample to be assessed (e.g., for the presence, absence, or amount of one or more analytes) using the methods or materials (e.g., devices or systems) provided herein can be obtained from any appropriate animal. In some cases, a sample to be assessed as described herein can be obtained from a mammal (e.g., a human such as a human neonate, human baby, human toddler, human child, or human adult). Examples of mammals that samples can be obtained from include, without limitation, primates (e.g., humans and monkeys), dogs, cats, horses, cows, pigs, sheep, rabbits, and rodents (e.g., mice and rats). Other examples of animals that samples can be obtained from include, without limitation, fish, avian species (e.g., chickens, turkeys, ostrich, emus, cranes, and falcons) and non-mammalian animals (e.g., mollusks, frogs, lizards, snakes, and insects).

[0023] In some cases, a sample to be inserted into a device or system described herein can be obtained from a source (e.g., a human neonate) and directly inserted into the device or system without being pre-processed. For example, a whole blood sample can be obtained from a mammal (e.g., a human such as a human neonate) and directly inserted into a device or system provided herein without being pre-processed (e.g., without being treated or manipulated in any way).

[0024] In some cases, a sample to be inserted into a device or system described herein can be obtained from a source (e.g., a mammal or surface) and processed prior to being inserted into the device or system (e.g., can be pre-processed). Samples that are pre-processed can be pre-processed using one or more appropriate reagents (e.g., enzymes, acids, bases, buffers, detergents, anticoagulants, and/or aptamers) and/or techniques (e.g., purification techniques, centrifugation techniques, amplification techniques, culturing techniques, and/or denaturing techniques). For example, a blood sample can be obtained from a mammal (e.g., a human) and treated with one or more anticoagulants. Examples of anticoagulants that can be used to pre-process a sample (e.g., a blood sample) include, without limitation, EDTA, citrate (trisodium citrate), heparinates (e.g., sodium, lithium, or ammonium salt of heparin or calcium-titrated heparin), and hirudin. In some cases, a sample (e.g., a sample suspected to contain a microorganism) to be inserted into a device or system described herein can be obtained from a source (e.g., a food preparation surface) and pre-processed by culturing the sample with appropriate culture media for a period of time (e.g., 4 hours to 24 hours) prior to being inserted into the device or system. Examples of other pre-processing techniques that can be performed prior to inserting the sample into a device or system described herein include, without limitation, centrifugation to obtain cell-containing material, centrifugation to obtain cell-free material, filtration to remove cell containing material, cell lysis, nucleic acid purification, protein purification, nucleic acid amplification (e.g., polymerase chain reaction (PCR)), reverse transcription to obtain cDNA, reverse transcription PCR, nucleic acid denaturation, and isothermal amplification.

[0025] In some cases, the methods and materials provided herein can be used in small animal research, neonatal blood analysis, analysis of blood for one or more cardiac biomarkers, point-of-care testing of infectious diseases (e.g., COVID-19, sexually transmitted diseases, or HIV), and/or point-of-care testing in an operating room to provide rapid turnaround results.

[0026] In some embodiments, with reference to FIGS. 1 and 2, microfluidic device 10 can include a sample inlet area 104. Sample inlet area 104 can be designed to receive and hold a volume of a sample ranging from 1 μL to 100 μL (e.g., from 1 μL to 75 μL, from 1 μL to 50 μL, from 1 μL to 25 μL, from 10 μL to 100 μL, from 25 μL to 100 μL, from 50 μL to 100 μL, from 25 μL to 75 μL, from 1 μL to 10 μL, from 2 μL to 10 μL, from 3 μL to 10 μL, from 4 μL to 10 μL, from 1 μL to 9 μL, from 1 μL to 8 μL, from 1 μL to 7 μL, from 1 μL to 6 μL, from 2 μL to 8 μL, from 3 μL to 7 μL, or from 4 μL to 6 μL).

[0027] Microfluidic device 10 can include an inlet 11 of channel 13 to receive the sample or a portion of the sample that was inserted into sample inlet area 104. In some cases, a filter or membrane 106 (e.g., a plasma separation membrane) can be located between sample inlet area 104 and inlet 11 to restrict at least some material of an inserted sample from entering channel 13. For example, when microfluidic device 10 includes plasma separation membrane 106 and whole blood is inserted into sample inlet area 104, plasma can be allowed to enter channel 13 while cells within the sample are restricted from entering channel 13.

[0028] In some cases, microfluidic device 10 can include a vacuum port configured to apply negative pressure to channel 13. In such cases, application of negative pressure can draw a sample or a portion of a sample from sample inlet area 104 into channel 13. In some cases, channel 13 can include a serpentine path 15. Channel 13 can have any appropriate length. In some cases, channel 13 can have a length from inlet 11 to vacuum port 14 that is from 10 mm to 200 mm (e.g., from 15 mm to 200 mm, from 25 mm to 200 mm, from 50 mm to 200 mm, from 75 mm to 200 mm, from 100 mm to 200 mm, from 10 mm to 175 mm, from 10 mm to 150 mm, from 25 mm to 150 mm, from 35 mm to 150 mm, from 50 mm to 150 mm, from 75 mm to 150 mm, from 100 mm to 150 mm, from 50 mm to 175 mm, from 75 mm to 175 mm, from 100 mm to 175 mm, from 125 mm to 175 mm, from 130 mm to 140 mm, from 125 mm to 145 mm, or 120 mm to 150 mm). Channel 13 can hold any appropriate volume of sample material. In some cases, channel 13 can hold a maximum volume from inlet 11 to vacuum port 14 that is from 0.5 μL to 5 μL (e.g., from 0.5 μL to 5 μL, from 0.75 μL to 5 μL, from 1 μL to 5 μL, from 1.5 μL to 5 μL, from 2 μL to 5 μL, from 0.5 μL to 4.5 μL, from 0.5 μL to 4 μL, from 0.5 μL to 3.5 μL, from 0.5 μL to 3 μL, from 0.5 μL to 2.5 μL, from 0.5 μL to 2 μL, from 0.75 μL to 2 μL, or from 1 μL to 2 μL).

[0029] In some cases, microfluidic device 10 can include a positive pressure port 16, a positive pressure channel 8, a positive pressure actuator port 20, a positive pressure valve 17, a sample cutoff actuator port 18, and a sample cutoff valve 19. Positive pressure valve 17 can be closed and sample cutoff valve 19 can be open while negative pressure is being applied to vacuum port 14 to draw sample from sample inlet area 12 into channel 13, for example, along serpentine path 15. Once an adequate volume of sample is drawn into channel 13 via negative pressure, sample cutoff actuator port 18 can be activated to close sample cutoff valve 19, and positive pressure actuator port 20 can be activated to open positive pressure valve 17. At this point, positive pressure can be applied to positive pressure port 16 to provide positive pressure to positive pressure channel 8 and channel 13 to move sample within channel 13 to the one or more sample chambers 22 of channel 13. FIG. 1 shows four sample chambers with the sample chamber of the lower part of FIG. 1 being labelled as sample chamber 22a and with the sample chamber of the upper part of FIG. 1 being labelled as sample chamber 22b. Microfluidic device 10 can include any appropriate number of sample chambers. For example, microfluidic device 10 can be configured to have one, two, three, four, five, six, seven, eight, nine, ten, or more sample chambers.

[0030] As shown in FIG. 1, the one or more sample chambers 22 of channel 13 can be in series along channel 13. In some cases, each of sample chamber 22 of channel 13 is defined by an inflow valve 26 and an outflow valve 27. Each sample chamber 22 of channel 13 defined by inflow valve 26 and outflow valve 27 can be designed to hold any appropriate volume of sample material. In some cases, each sample chamber 22 can hold a maximum volume that is from 20 nL to 500 nL (e.g., from 20 nL to 475 nL, from 20 nL to 450 nL, from 20 nL to 425 nL, from 20 nL to 400 nL, from 20 nL to 350 nL, from 20 nL to 300 nL, from 20 nL to 250 nL, from 20 nL to 200 nL, from 20 nL to 150 nL, from 20 nL to 100 nL, from 20 nL to 75 nL, from 20 nL to 50 nL, from 30 nL to 500 nL, from 35 nL to 500 nL, from 30 nL to 100 nL, from 30 nL to 75 nL, from 30 nL to 50 nL, or from 35 nL to 45 nL). While loading each sample chamber 22 with sample, inflow valves 26 and outflow valves 27 along channel 13 can be open. Once each sample chamber 22 is loaded with sample, a master valve actuator port 65 can be activated to close inflow valves 26 and outflow valves 27 along channel 13 and isolate sample within each sample chamber 22.

[0031] With further reference to FIG. 1, microfluidic device 10 can include one or more reagent chambers 23. FIG. 1 shows four reagent chambers with the reagent chamber of the lower part of FIG. 1 being labelled as reagent chamber 23a and with the reagent chamber of the upper part of FIG. 1 being labelled as reagent chamber 23b. Microfluidic device 10 can include any appropriate number of reagent chambers. For example, microfluidic device 10 can be configured to have one, two, three, four, five, six, seven, eight, nine, ten, or more reagent chambers. Typically, one sample chamber 22 is configured to be in fluid communication with one reagent chamber 23 when a reaction control valve 34 located between them is open. For example, sample chamber 22a is in fluid communication with reagent chamber 23a when reaction control valve 34 is open. When reaction control valve 34 is closed, sample chamber 22a and reagent chamber 23a are not in fluid communication.

[0032] As shown in FIG. 1, microfluidic device 10 can include a master valve actuator port 36 configured to control each reaction control valve 34. In some cases, however, microfluidic device 10 can include a separate valve actuator port to control each reaction control valve 34 independently.

[0033] In some cases, each of reagent chambers 23 is defined by a reagent inflow valve 28 and a reagent outflow valve 29. Each reagent chamber 23 defined by reagent inflow valve 28 and reagent outflow valve 29 can be designed to hold any appropriate volume of reagent(s). In some cases, each reagent chamber 23 can hold a maximum volume that is from 20 nL to 500 nL (e.g., from 20 nL to 475 nL, from 20 nL to 450 nL, from 20 nL to 425 nL, from 20 nL to 400 nL, from 20 nL to 350 nL, from 20 nL to 300 nL, from 20 nL to 250 nL, from 20 nL to 200 nL, from 20 nL to 150 nL, from 20 nL to 100 nL, from 20 nL to 75 nL, from 20 nL to 50 nL, from 30 nL to 500 nL, from 35 nL to 500 nL, from 30 nL to 100 nL, from 30 nL to 75 nL, from 30 nL to 50 nL, or from 35 nL to 45 nL). While loading each reagent chamber 23 with reagent(s), reagent inflow valves 28 and reagent outflow valves 29 along reagent channel 31 can be open. Once each reagent chamber 23 is loaded with reagent(s), a master valve actuator port 65 can be activated to close reagent inflow valves 28 and reagent outflow valves 29 along channel 31 and isolate reagent(s) within each reagent chamber 23.

[0034] Microfluidic device 10 can include a reagent inlet port 30 and reagent outlet port 32 for loading reagent(s) into reagent channel 31. Any appropriate reagent or set of reagents can be loaded into a reagent chamber 23. For example, when microfluidic device 10 is designed to detect glucose in a plasma sample, glucose oxidase, horseradish peroxidase, 4-aminoantipyrine (4-AAP), and ADOS reagents can be loaded into reagent chamber 23a and reagent chamber 23a can be designated for glucose detection. When that same microfluidic device 10 is designed to also detect direct bilirubin in a plasma sample, hydrochloric acid, sulfanilic acid, sodium nitrite, and sodium bicarbonate reagents can be loaded into reagent chamber 23b and reagent chamber 23b can be designated for bilirubin detection.

[0035] In some cases, microfluidic device 10 can include the ability to perform similar assays being performed on the sample (e.g., a plasma sample) inserted into sample inlet area 12 on a positive control sample, a negative control sample, or both a positive control sample and a negative control sample. For example, microfluidic device 10 can include an additional valve 38 along reagent channel 31 to create a negative control reagent chamber 25 and/or an additional valve 40 along reagent channel 31 to create a positive control reagent chamber 24. FIG. 1 shows four negative control reagent chambers with the negative control reagent chamber of the lower part of FIG. 1 being labelled as negative control reagent chamber 25a and with the negative control reagent chamber of the upper part of FIG. 1 being labelled as negative control reagent chamber 25b. FIG. 1 also shows four positive control reagent chambers with the positive control reagent chamber of the lower part of FIG. 1 being labelled as positive control reagent chamber 24a and with the positive control reagent chamber of the upper part of FIG. 1 being labelled as positive control reagent chamber 24b.

[0036] Each positive control reagent chamber 24 and/or each negative control reagent chamber 25 can be loaded with reagent(s) as each reagent chamber 23 are being loaded. For example, positive control reagent chamber 24a, negative control reagent chamber 25a, and reagent chamber 23a can be loaded with the same reagent(s) via reagent inlet port 30. As another example, positive control reagent chamber 24b, negative control reagent chamber 25b, and reagent chamber 23b can be loaded with the same reagent(s) via their corresponding reagent inlet port.

[0037] Once each positive reagent chamber 24 and/or negative reagent chamber 25 is loaded with reagent(s), master valve actuator port 65 can be activated to close reagent inflow valves 28, reagent outflow valves 29, additional valves 38, and additional valves 40 along reagent channel 31 and to isolate reagent(s) within reagent chamber 23, positive reagent chamber 24, and/or negative reagent chamber 25.

[0038] In some cases, positive reagent chamber 24 and/or negative reagent chamber 25 for each reagent chamber 23 can be configured to hold the same volume as that reagent chamber 23.

[0039] When microfluidic device 10 includes a positive control for a particular assay, microfluidic device 10 can include a positive sample inlet port 42, a positive sample outlet port 44, a positive control sample channel 46, a positive sample inflow valve 48 along positive control sample channel 46, a positive sample outflow valve 52 along positive control sample channel 46, and a positive sample chamber 50 defined by positive sample inflow valve 48 and positive sample outflow valve 52.

[0040] Each positive sample chamber 50 defined by positive sample inflow valve 48 and positive sample outflow valve 52 can be designed to hold any appropriate volume of positive control material. In some cases, each positive sample chamber 50 can hold a maximum volume that is from 20 nL to 500 nL (e.g., from 20 nL to 475 nL, from 20 nL to 450 nL, from 20 nL to 425 nL, from 20 nL to 400 nL, from 20 nL to 350 nL, from 20 nL to 300 nL, from 20 nL to 250 nL, from 20 nL to 200 nL, from 20 nL to 150 nL, from 20 nL to 100 nL, from 20 nL to 75 nL, from 20 nL to 50 nL, from 30 nL to 500 nL, from 35 nL to 500 nL, from 30 nL to 100 nL, from 30 nL to 75 nL, from 30 nL to 50 nL, or from 35 nL to 45 nL). While loading each positive sample chamber 50 with positive control material, positive sample inflow valve 48 and positive sample outflow valve 52 along positive control sample channel 46 can be open and positive control material can be inserted into positive sample inlet port 42. Once each positive sample chamber 50 is loaded with positive control material, a master valve actuator port 65 can be activated to close positive sample inflow valve 48 and positive sample outflow valve 52 along positive control sample channel 46 and isolate positive control material within each positive sample chamber 50.

[0041] In some cases, one positive sample chamber 50 is configured to be in fluid communication with one positive control reagent chamber 24 when a positive control reaction control valve 54 located between them is open. For example, positive sample chamber 50 is in fluid communication with positive control reagent chamber 24b when positive control reaction control valve 54 is open. When positive control reaction control valve 54 is closed, positive sample chamber 50 and positive control reagent chamber 24b are not in fluid communication.

[0042] As shown in FIG. 1, microfluidic device 10 can include a master valve actuator port 36 configured to control each positive control reaction control valve 54. In some cases, however, microfluidic device 10 can include a separate valve actuator port to control each positive control reaction control valve 54 independently.

[0043] When microfluidic device 10 includes a negative control for a particular assay, microfluidic device 10 can include a negative sample inlet port 56, a negative sample outlet port 58, a negative control sample channel 57, a negative sample inflow valve 60 along negative control sample channel 57, a negative sample outflow valve 62 along negative control sample channel 57, and a negative sample chamber 61 defined by negative sample inflow valve 60 and negative sample outflow valve 62.

[0044] Each negative sample chamber 61 defined by negative sample inflow valve 60 and negative sample outflow valve 62 can be designed to hold any appropriate volume of negative control material. In some cases, each negative sample chamber 61 can hold a maximum volume that is from 20 nL to 500 nL (e.g., from 20 nL to 475 nL, from 20 nL to 450 nL, from 20 nL to 425 nL, from 20 nL to 400 nL, from 20 nL to 350 nL, from 20 nL to 300 nL, from 20 nL to 250 nL, from 20 nL to 200 nL, from 20 nL to 150 nL, from 20 nL to 100 nL, from 20 nL to 75 nL, from 20 nL to 50 nL, from 30 nL to 500 nL, from 35 nL to 500 nL, from 30 nL to 100 nL, from 30 nL to 75 nL, from 30 nL to 50 nL, or from 35 nL to 45 nL). While loading each negative sample chamber 61 with negative control material, negative sample inflow valve 60 and negative sample outflow valve 62 along negative control sample channel 57 can be open and negative control material can be inserted into negative sample inlet port 56. Once each negative sample chamber 61 is loaded with negative control material, a master valve actuator port 65 can be activated to close negative sample inflow valve 60 and negative sample outflow valve 62 along negative control sample channel 57 and isolate negative control material within each negative sample chamber 61.

[0045] In some cases, one negative sample chamber 61 is configured to be in fluid communication with one negative control reagent chamber 25 when a negative control reaction control valve 64 located between them is open. For example, negative sample chamber 61 is in fluid communication with negative control reagent chamber 25b when negative control reaction control valve 64 is open. When negative control reaction control valve 64 is closed, negative sample chamber 61 and negative control reagent chamber 25b are not in fluid communication.

[0046] As shown in FIG. 1, microfluidic device 10 can include a master valve actuator port 36 configured to control each negative control reaction control valve 64. In some cases, however, microfluidic device 10 can include a separate valve actuator port to control each negative control reaction control valve 64 independently.

[0047] In some cases, microfluidic device 10 can include a master valve actuator port 36 configured to control each reaction control valve 34, each positive control reaction control valve 54, and each negative control reaction control valve 64.

[0048] Any appropriate method can be used to make a microfluidic device provided herein. For example, multilayer soft lithography techniques such as those described elsewhere (Unger et al., Science, 288:113-116 (2000); Gonzalez-Suarez et al., Anal. Chem., 90:8331-8336 (2018); and de Hoyos-Vega et al., Microsystems Nanoeng., 6:40 (2020)) can be used to make a microfluidic device provided herein. Any appropriate type of microfluidic valve and actuator port can be used as a valve and actuator port described herein. For example, valves and actuator ports such as those described elsewhere (Thorsen et al., Science, 298:580-584 (2002); and Lee et al., Lab Chip, 18:1207-1214 (2018)) can be used to make one or more of the valves and actuator ports described herein.

[0049] The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.

EXAMPLES

Example 1—Microfluidic Device for Plasma Separation and Analysis of Biomarkers Using 5 μL of Whole Blood

[0050] A microfluidic device 10 comprising two layers was fabricated by multilayer soft lithography (FIG. 1). It included a module to separate plasma from 5 μL of whole blood by using a plasma separation membrane system (PSM, Cobetter Filtration; see items 104 and 106 of FIG. 2) and an assay module for up to four different biomarkers (FIG. 1). Plasma was separated by applying negative pressure to vacuum port 14 to pull plasma into a long microchannel 13 that can hold a volume of 1 μL. A plasma separation to membrane 106 (PSM; Cobetter Filtration) prevents blood cells from moving into the microchannel. Plasma was pushed to four sample chambers 22 using positive pressure applied at positive pressure port 16 and then isolated for testing using inflow valves 26 and outflow valves 27 for each sample chamber. The inflow and outflow values were controlled using master valve activator port 65. Assay reagents were previously loaded into device 10 and then actively mixed with plasma to develop the desired reaction. Positive and negative controls were tested simultaneously with plasma.

[0051] Prior to plasma biomarkers analysis, plasma separation efficiency was tested. A microfluidic device 100 comprising only the plasma separation module (FIG. 2) was used to evaluate quality of separated plasma compared to a centrifugation method, which is currently a gold standard. Using a spectrophotometer (NanoDrop, Thermo Fisher) and commercially available kits, absorbance for hemoglobin, direct and total bilirubin, and protein abundancy (absorbance at 280 nm) was measured (FIG. 3).

[0052] After plasma testing, food dyes were used to show mixing efficiency of active mixing enabled by sequential activation of two microfluidic valves to show homogeneity in all reaction chambers (FIG. 4).

[0053] The capability of device to perform enzymatic assays was assessed by using glucose (colorimetric) and lactic acid dehydrogenase (LDH, fluorescent) reactions (FIGS. 5A and 5B).

[0054] A glucose assay was tested on plasma separated from 5 μL of whole blood using microfluidic device 10. A glucose solution (8 mM) and PBS 1X were used as positive and negative controls, respectively (FIG. 6).

Results

[0055] Plasma separation from whole blood using a microfluidic device exhibited similar results as those obtained when plasma was separated by centrifugation. These results demonstrate that no, or little, cell lysis occurs when using PSM and vacuum. There was a decrease of about 15% in protein abundance for the microfluidic device possibly due to PDM adsorption.

[0056] Food dyes allowed for a qualitative analysis of device homogeneity in all reaction chambers, ensuring a complete mixing between both chambers in about 10 minutes. In comparison, diffusion mixing takes up to 3 hours.

[0057] For glucose colorimetric assay, a solution containing glucose oxidase, horseradish peroxidase, 4-AAP, and ADOS was injected into the plasma channel and four concentrations of glucose were injected into the reagents chambers (0, 1, 5, and 10 mM). Reaction was carried out by active mixing taking images every minute for a total of 25 minutes. Magenta intensity was analyzed in last images and graphed (FIG. 5A). Analysis showed a very good correlation between glucose concentration and color intensity. LDH assay was carried out in the same fashion, showing capability of the device to perform fluorescence-based assays (FIG. 5B).

[0058] Whole blood from a blood bank was separated in the device and tested with a similar methodology as that of the glucose assay, using high concentration tested serum (19 mM) as a positive control. Results showed a good plasma separation with no signs of blood cells in the microchannels. The glucose assay showed an expected lower concentration for the sample glucose compared to the glucose solution (8 mM) positive control, and no signal for the negative control (FIG. 6).

[0059] These results confirm the development of a microfluidic device for plasma separation and analysis using small whole blood sample volumes (e.g., from 1 μL to 10 μL of whole blood). Multiple reactions (e.g., two, three, four, five, six, or more) reactions, colorimetric and/or fluorescent, can be carried out in the device simultaneously.

Other Embodiments

[0060] It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.