Abstract
A coupled enzyme reaction assay to measure the activity of a first enzyme in a sample taken from a patient. The reaction assay includes a test well which includes a freeze-dried mixture having two layers where the first layer includes first tethered enzyme nanobots, where each nanobot has a nanoparticle tethered to a set of second enzymes. A second layer is introduced into the test well. The set of second enzymes are adapted to react with a substrate within the test well. The first layer of the freeze-dried mixture includes second tethered nanobots formed by tethering a nanoparticle to a set of third enzymes to provide oriented immobilization of the set of the third enzymes. The third enzymes react to produce a signal for determining the amount of enzymatic activity of the first enzyme in the sample from the patient.
Claims
1. A coupled enzyme reaction assay for measuring the activity of a first enzyme in a sample from a patient comprising: at least one test well comprising a freeze-dried mixture of a multiplicity of components including at least two layers, each layer separately introduced into the well during preparation, the at least two layers including a first layer including a plurality of first tethered enzyme nanobots, each of the tethered enzyme nanobots having a nanoparticle tethered to a set of second enzymes, the tethering being structured to provide oriented immobilization of the set of the second enzymes; the freeze-dried mixture further including a second layer, the second layer being introduced into the at least one test well after the first layer has been introduced and frozen, the second layer including a first substrate that is converted into a second substrate by the first enzyme when the first enzyme is introduced into the at least one test well from the sample from the patient; the set of the second enzymes of the first tethered nanobots being adapted to react with the second substrate produced by the first enzyme in the presence of the components in the freeze-dried mixture to produce a third substrate; the first layer of the freeze-dried mixture further including a plurality of second tethered nanobots formed by tethering a nanoparticle to a set of third enzymes, the tethering being structured to provide oriented immobilization of the set of the third enzymes, the set of third enzymes of the second tethered nanobots adapted to react with the third substrate in the presence of the multiplicity of components in the freeze dried mixture to produce a signal for determining the amount of enzymatic activity of the first enzyme in the sample from the patient.
2. The assay of claim 1 where the first enzyme is selected from at least one of the group selected from enolase, neuron specific enolase, alanine aminotransferase, and aspartate aminotransferase.
3. The assay of claim 1 where the second enzyme is selected from the group of pyruvate kinase when the first enzyme is enolase or neuron specific enolase, and glutamate oxidase when the first enzyme is alanine aminotransferase or aspartate aminotransferase.
4. The assay of claim 1 where the third enzyme is selected from at least one of the group consisting of luciferase, pyruvate oxidase, and horse radish peroxidase.
5. The assay of claim 1 where the first substrate is selected from at least one of the group consisting of: 2-phosphoglycerate when the first enzyme is enolase or neuron specific enolase, L-Alanine when the first enzyme is alanine aminotransferase, and L-Aspartate when the first enzyme is aspartate aminotransferase.
6. The assay of claim 1 where the signal is selected from at least one of the group consisting of: luminescence, absorbance, fluorescence, electrical current, electrical conductance, colorimetric change and electrical resistance.
7. The assay of claim 1 where the multiplicity of components include at least one of the group consisting of: adenosine di-phosphate, luciferin, ketoglutarate, and luminal.
8. The assay of claim 1 further comprising at least one additional well selected from the group of: a negative control well, and a positive control well.
9. The assay of claim 8 where the negative control well includes only the first layer of the freeze-dried mixture of the test well.
10. The assay of claim 8 where the positive control well includes both first and second layers of the test well, the positive control layer further including a third layer introduced after the first and second layers have been sequentially introduced and frozen.
11. The assay of claim 10 where the third layer includes a pre-selected quantity of the first enzyme, the sequential freezing steps being required to prevent activity of the first enzyme from initiating the reaction until liquid is introduced into the positive control well.
12. The assay of claim 11 where a multiplicity of the first enzyme is tethered to each of a multiplicity of nanoparticles.
13. The assay of claim 8 having at least one positive control well that includes in its first layer a pre-set quantity of the first enzyme.
14. The assay of claim 8 where a relative activity of the first enzyme in the sample being assayed is determined by a formula based on the difference in signal generated by the second tethered nanobots in the at least one test well compared to the signal generated by second tethered nanobots in the at least one negative control well.
15. The assay of claim 8 where a relative activity of the first enzyme is determined by a formula based on the value of the signal generated by the at least one test well, the signal generated by the at least one negative control well and the signal generated by the at least one positive control well.
16. The assay of claim 14 where the assay includes a pre-set positive diagnosis threshold where a positive diagnosis for the assay is based on a comparison of a measured activity of the first enzyme from the sample being assayed against the preset positive diagnosis threshold.
17. The assay of claim 14 where the relative activity is measured as a percentage.
18. The assay of claim 17 where the assay includes a pre-set positive diagnosis threshold set as a percentage where a positive diagnosis for the assay is based on a comparison of a measured activity of the first enzyme against the preset positive diagnosis threshold for a positive diagnosis.
19. The assay of claim 16 where the relative activity is measured as a percentage.
20. The assay of claim 19 where a positive test interpretation results from the measured activity of the first enzyme exceeding the preset positive diagnosis threshold.
21. The assay of claim 1 where the nanoparticles are selected from the group selected from: Silica; Polycarbonate; Acrylics including lucite; Reflective materials including silver, gold and platinum; and Ceramics.
22. The assay of claim 1 where the nanoparticles are selected in a size range selected from the group of: 1 nm to 500 nm, and 500 nm to 1,000 nm.
23. The assay of claim 1 where the approximate nanoparticle shape is selected from the group of: Spherical, Cylindrical including nanowires, Mesoporous, Plates, Oblate spheroids, and Other heterogeneous shapes.
24. A coupled enzyme reaction assay for acute brain injury by measuring the enzymatic activity of Enolase in a blood sample from a patient comprising: a structure having at least one each of three types of wells comprising test wells, negative control wells and positive control wells; at least one test well comprising a freeze-dried mixture of components in two layers separately introduced into the test well during fabrication, a first layer of the at least two layers comprising adenosine di-phosphate, luciferin and a multiplicity of a first tethered enzyme nanobot, each of the first tethered enzyme nanobots being a silica nanoparticle tethered to a multiplicity of pyruvate kinase enzymes, the tethering being structured to provide oriented immobilization of the pyruvate kinase enzymes; the first layer further comprising a multiplicity of second tethered enzyme nanobots, each second tethered enzyme nanobot formed by tethering a silica nanoparticle to a multiplicity of luciferase enzymes, the tethering being structured to provide oriented immobilization of the luciferase enzymes; the two layers of the at least one test well further comprising a second layer, the second layer being introduced into the at least one test well after the first layer has been introduced and subsequently frozen, the second layer including the substrate 2-phosphoglycerate; the at least one negative control well comprising a single layer having the same components as the first layer of the at least one test well; the at least one positive control well comprising two layers, with the first layer of the two layers having the same components as the first layer of the at least one test well with the addition of a preset amount of enolase and the second layer of the two layers having the same components as the second layer of the at least one test well.
25. The assay of claim 24 wherein the first and second layers also include one or more other materials selected from: stabilizers, dispersants, cofactors, reaction modulators, buffers and cryoprotectants.
26. The assay of claim 24 wherein the structure of the wells have a top and a bottom and one or more of the following: at least one tapered portion having a larger cross sectional on the portion closest to the top of the well, a rounded bottom, a volume of less than 0.1 ml, and a shape adapted to fit into a holder the size of a standard 96-well plate.
27. The assay of claim 24 wherein the first and second layers also include one or more other materials selected from: Sorbitol, Dextran, Trehalose, Potassium ions, Magnesium ions, Phosphate ions, Sodium ions, HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), Glycerol, Polyethylene glycol, Raffinose, Sucrose, Dextrose, and Potassium Sorbate.
28. The assay of claim 24 wherein the first and second layers also include Dextran, Trehalose, Potassium ions, Magnesium ions, Phosphate ions, Sodium ions, and HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid).
29. The assay of claim 24 where the test wells, negative control wells and positive control wells are freeze dried after all layers are introduced.
30. The assay of claim 24 where the activity of Enolase from the sample is determined by a value of a luminescence generated by the second nanobots.
31. The assay of claim 30 where the activity of the Enolase is determined by the value of the luminescence generated by the second nanobots in the at least one test well compared to a luminescence generated by second nanobots in the at least one negative control well.
32. The assay of claim 24 where a positive test for acute brain injury is determined when a measured activity of the first enzyme from the patient sample exceeds a preset threshold.
33. The assay of claim 24 where a measured activity of Enolase is determined by comparison of a value of a luminescence generated by the second nanobots in the at least one test well to a luminescence generated by the second nanobots in the at least one negative control well and the at least one positive control well.
34. The assay of claim 33 where the measured activity of Enolase is determined by comparison of the difference of an adjusted luminescence value being the difference in the luminescence from the at least one test well to the at least one negative control well as compared to the difference in the luminescence between the at least one positive control well and the at least one test well.
35. The assay of claim 34 where the adjusted luminescence value is measured as a percentage.
36. The assay of claim 35 where the measured activity of Enolase includes a preset threshold for a positive test for the adjusted luminescence value, the positive test indicative of a significant level of active Enolase.
37. A coupled enzyme reaction assay for luminescence-based measuring of the activity of liver enzymes ALT or AST in a sample from a patient comprising: a pre-treatment container into which the sample from the patient is introduced, the container comprising preset amounts of uricase and uric acid; a structure having at least one each of three types of wells comprising test wells, negative control wells and positive control wells into which a modified sample from the pre-treatment container is introduced; the at least one test well comprising a freeze-dried mixture of a multiplicity of components in a first layer and a second layer separately introduced into the test well during fabrication, the first layer comprising luminol and a multiplicity of two types of tethered enzyme nanobots, a set of first tethered enzyme nanobots each being a silica nanoparticle tethered to a multiplicity of glutamate oxidase enzymes, the tethering being structured to provide oriented immobilization of the multiplicity of the glutamate oxidase enzymes; a set of second tethered enzyme nanobots, each being a silica nanoparticle tethered to a multiplicity of horseradish peroxidase enzymes, the tethering being structured to provide oriented immobilization of the multiplicity of horseradish peroxidase enzymes; the second layer of the test well mixture being introduced into the at least one test well after the first layer has been introduced and subsequently frozen, the second layer comprising ?-ketoglutarate and an additional substrate selected from the list group of: L-Alanine for ALT, and L-Aspartate for AST; the at least one negative control well comprising a freeze-dried mixture with only one layer having the same components as the first layer of the at least one test well; and the at least one positive control well comprising a freeze-dried mixture with two layers, with the second layer having the same components as the second layer of the at least one test well and a first layer having the same components with the addition of a preset amount of an enzyme selected from the list of: ALT for the ALT assay and AST from the AST assay.
38. The assay of claim 37 wherein the first and second layers also include one or more other materials selected from the list group of: stabilizers, dispersants, cofactors, reaction modulators, buffers and cryoprotectants.
39. The assay of claim 37 where the patient sample is selected from the group selected from: whole blood, blood plasma, and blood serum.
40. The assay of claim 37 where the first and second layers also include at least one or more other materials selected from the group selected from: Sorbitol, Dextran, Trehalose, Potassium ions, Magnesium ions, Phosphate ions, Sodium ions, HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), Glycerol, Polyethylene glycol, Raffinose, Sucrose, Dextrose, Potassium Sorbate, Pyridoxal 5-phosphate, and Vitamin B6.
41. The assay of claim 37 where the first and second layers also include Dextran, Trehalose, Potassium ions, Magnesium ions, Phosphate ions, Sodium ions, and HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), and Pyridoxal 5-phosphate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0135] FIG. 1 is a block diagram showing an embodiment of the steps in a three stage TET assay, such as for detection of a biomarker that itself has catalytic enzyme activity.
[0136] FIG. 2 is a table showing an embodiment of the lists of well component for TET assays for NSE-FA, and liver function enzymes ALT and AST.
[0137] FIG. 3A is a diagram showing an embodiment of the test well components for the assay for NSE-FA
[0138] FIG. 3B is a diagram showing an embodiment of the process that occurs when a liquid sample containing enzymatically active NSE is inserted into the present invention reaction test well or zone.
[0139] FIG. 3C is a block diagram of an embodiment of the method using tethered enzymes to measure liver enzymes directly from plasma or serum.
[0140] FIG. 4A is a schematic view of an embodiment of the TET custom IVD strip designed for placement into the holder for a standard plate reader device.
[0141] FIG. 4B is a cross sectional view of an embodiment of the shape of the wells in the strip of FIG. 4A showing the three layers of components of reaction test and positive control wells.
[0142] FIG. 4C is a cross sectional view of a preferred embodiment showing the shape of three wells in a strip with two layers shown for positive control, test and negative control wells.
[0143] FIG. 5 is a block diagram of an embodiment of the enzyme production process using bacteria to produce enzymes designed for tethering.
[0144] FIG. 6 is a block diagram of an embodiment of the enzyme tethering process.
[0145] FIG. 7 is a block diagram of an example of a preferred embodiment of the production process for the assay strips of FIG. 4A, including the steps for inserting the materials that are placed into the wells/zones for the present invention TET coupled enzyme assay of FIG. 1.
[0146] FIG. 8 is a top view of a preferred embodiment of a production module being a standard 96-well, 8-strip holder with eight empty 12-well strips.
[0147] FIG. 9A is a top view of the production module with holder and with the eight strips after a first layer has been deposited into the test and negative control wells.
[0148] FIG. 9B is a top view of the production module with the eight strips after completion of sub-process 1 of FIG. 7.
[0149] FIG. 9B is a top view of the production module with eight strips as it would be after step 2-2 of sub-process 2 of FIG. 7.
[0150] FIG. 9C is a top view of the production module with eight strips on the freezer block as it would be after completed step 3-1 of sub-process 3 of FIG. 7.
[0151] FIG. 9D is a top view of the configuration of the completed production module.
[0152] FIG. 10A is a schematic view of the freezer block with depression placed on top of an insulating pad with pedestals to limit the heat flow from the insulating pad to the freezer block so it will remain at a cold temperature during sub-process 3 of FIG. 7.
[0153] FIG. 10B is a schematic view of the Freezer block with a handle inserted into slots in the freezer block.
[0154] FIG. 11A is a graph showing an example of the luminescence data from a 12-well strip (e.g., the output of an NSE-FA diagnostic strip) following insertion of a patient plasma sample into each well.
[0155] FIG. 11B is a graph showing an alternate algorithmic embodiment to measure luminescence data from a coupled enzyme reaction.
[0156] FIG. 11C is a graph showing an alternate algorithmic embodiment to measure luminescence data from a coupled enzyme reaction.
[0157] FIG. 12A is a top view showing the blood separation paper strip set with negative control strip, test strip and positive control strip as they might be configured before being used in a Point of Care (PoC) diagnostic assay.
[0158] FIG. 12B is a top view showing the strips at a time of several seconds after a patient's blood has been placed onto each of the three blood separation paper strips.
[0159] FIG. 12C is a top view showing the assay strips as the plasma has now filled the reaction zones and is filling the flow extension zones of the blood separation paper strips.
[0160] FIG. 12D is a top view showing an alternate embodiment of the lateral flow blood separation paper strip set.
[0161] FIG. 12E is a top view showing the blood separation paper strip set for both liver enzymes ALT and AST as they would be configured before being used in a PoC diagnostic assay.
[0162] FIG. 13A is a schematic view showing an embodiment of a TET assay card configured for insertion into a photodiode-based reader.
[0163] FIG. 13B is a top view showing an embodiment of a TET diagnostic PoC card layout where the fluid input zone is centrally located with 5 blood separation strips leading to five reaction zones.
[0164] FIG. 14 is a schematic view of an embodiment of a TET coupled enzyme assay test module where a blood sample volume is deposited into an upper cylinder with strip holder and 4 blood separation paper strips.
[0165] FIG. 15 is a schematic view of an embodiment of a two-piece TASSO/TET assay system with a photodiode luminescence reader (PLR) and the TASSO blood collection device and the normal collection vial replaced by an embodiment of the TET coupled enzyme assay test module similar to the test module of FIG. 14 but with the addition of the alignment key.
[0166] FIG. 16 is a schematic view of an integrated and fully disposable point-of-care TET coupled enzyme assay system including a TASSO blood collection device.
[0167] FIG. 17 is a block diagram of an embodiment of the electronics module that has features that would be incorporated into either or both electronic module embodiments of FIG. 15 and FIG. 16.
[0168] FIG. 18 is a schematic view showing a preferred embodiment of a point of care blood collection device such as the TASSO with body, blood collection activator and microtainer shown with collected blood and bottom surface suitable for needle penetration.
[0169] FIG. 19 is a schematic view showing a preferred embodiment of a disposable NSE functional activity stroke test (NSE-FAST) assay.
DETAILED DESCRIPTION OF THE DRAWINGS
[0170] FIG. 1 is a block diagram showing an embodiment of the components in the test reaction well for a three stage TET coupled enzyme assay 100. Element P1 110 that may contain an enzyme biomarker E1 103 is a sample of body fluid (e.g., saliva, urine, mucus, blood or plasma/serum) being assayed, the sample 110 being inserted or flowing into a test well or test zone. In an alternate embodiment important for certain assays, for example assays for the liver enzymes ALT and AST, an additive A0 101 is combined with a precursor sample P0 102 to produce the sample P1 110. For assays that do not require a pre-treatment with A0 101, P0 102 is the same as P1 110.
[0171] The test well or zone would typically include the following components at the time the enzyme E1 103 is placed in the well or flows into the zone: [0172] SA1 111 and SA2 112 being the one or more substrates/co-factors/reagents on which the enzyme E1 103 acts to produce the one or more reaction products SB1 121 and/or SB2 122, with at least one that will serve as the substrate taken up by the first tethered enzyme nanobot TE1 120. Note that throughout this text and figures, use of the term substrate is meant to include any co-factors (inorganic or organic) or other reagents needed for the activity of the relevant enzyme, whether the enzyme is tethered as part of the TET diagnostic system. [0173] TE1 120, the first tethered enzyme nanobot that acts on the output substrate SB1 121 from E1 103 in conjunction with the substrate SB3 123 that is already in the test well or zone to produce the one or more reaction products SC1 131 and/or SC2 132 that can serve as substrates for the second tethered enzyme nanobot TE2 130. [0174] TE2 130, is the second tethered enzyme nanobot that acts on SC1 131 in conjunction with the substrate SC3 133 already in the well or zone to produce the output signal 140. Examples of output signals include light emission, color changes or electrical signals. [0175] Other materials 150 including buffers and cryo-protectants. For example Mg2+, KCl, Ca2+, HEPES, dextran, and/or sorbitol.
[0176] While FIG. 1 shows a coupled enzyme assay 100 with two tethered enzymes TE1 120 and TE2 130, it is envisioned that embodiments with only one or with three or more sequential coupled enzymes, each producing at least one needed substrate as input for the next in the sequence can be used, with the last tethered enzyme providing an output similar to the output 140 of TE2 130 shown here.
[0177] FIG. 2 is a table showing an embodiment of the lists of reaction well/zone components for TET-IVD or TET-PoC luminescence assays for the enzymes NSE-FA and liver enzymes ALT and AST. In a preferred embodiment of this assay formulation for NSE-FA and liver enzymes, P0 102 and P1 103 are plasma or serum produced from a patient's blood.
[0178] The pre-treatment element A0 101 for the liver enzyme assays is a combination of tethered uricase (TET-Uricase) plus uric acid that in a preferred embodiment is frozen or freeze dried either in a tablet, powder or onto the inside surface of a vial used to contain the plasma or serum. When thawed or exposed to liquid the uric acid will act as a substrate to the TET-Uricase to produce Hydrogen Peroxide H.sub.2O.sub.2. This pre-treatment step is an important aspect of the present invention as the H.sub.2O.sub.2 produced eliminates anti-oxidants from the sample P0 102 before it is added to the well or zone becoming the sample P1, 103. Specifically, without this the anti-oxidants such as ascorbic acid, uric acid, and glutathione, would otherwise diminish the enzymatically produced H.sub.2O.sub.2 as input for the final stage of the coupled reaction produced by TE2 130.
[0179] It is envisioned that other embodiments of the pre-treatment element A0 101 may include Glutathione s-transferase (GST), superoxide dismutase (SOD), and/or enzymes that are oxidases that following interaction with their subtrates create peroxides including hydrogen peroxide. These include: [0180] Uricase without uric acid [0181] Ascorbate oxidase with or without ascorbic acid, and [0182] Glucose oxidase with or without glucose
[0183] The initial substrates SA1 111 and SA2 112 on which the enzyme being detected works is 2-PG for NSE-FA and the combination of ?-ketoglutarate and L-Alanine for ALT and ?-ketoglutarate and L-Aspartate for AST. SB2 122 represents additional outputs of E1 103 that are not used in subsequent reactions SB2 122 of the reaction of ALT is Pyruvate and of AST is Oxaloacetate.
[0184] The first tethered enzyme TE1 120 is Pyruvate Kinase (PK) for NSE-FA and Glutamate Oxidase (Glut-Ox) for ALT and AST. An additional input pre-seeded in the well or zone for use with TE1 120 being Pyruvate Kinase is ADP as the substrate SB3 123. The output of the first Tethered enzyme SC1 131 is ATP for the NSE-FA assay and Hydrogen Peroxide (H.sub.2O.sub.2) for ALT and AST.
[0185] The second Tethered enzyme TE2 130 Is Luciferase for NSE-FA and Horse Radish Peroxidase for ALT and AST. The substrate in the mixture SC3 133 that is worked on by the second tethered enzyme TE2 is Luciferin for NSE-FA and Luminol for ALT and AST.
[0186] All three assays produce photons through luminescence as the output signal 140 from the second tethered enzyme TE2 130 being luciferase for NSE-FA and Horse Radish Peroxidase (HRP) for ALT and AST.
[0187] FIG. 3A is a diagram showing an embodiment of the well/zone 300 components for the three stage TET assay for functional activity of NSE (NSE-FA). These are the substrates 2-phosphoglycerate (2-PG) 301, Adenosine Diphosphate (ADP) 302, the first tethered enzyme Pyruvate Kinase (TET-PK) 303, Luciferin 304, the 2.sup.nd tethered enzyme Tethered Luciferase (TET-Luciferase) 305 and other materials 306.
[0188] FIG. 3B is a diagram showing an embodiment of the process 350 that occurs when active NSE-FA 310 is introduced into the reaction well 300. The sequential steps are: [0189] Step 351. The functionally active NSE placed in the well or flowing into a zone (NSE-FA) 310 will take up the substrate 2-PG 301 to produce Phosphoenolpyruvate (PEP) 311. The PEP 311 is released into the well/zone where the step 351 will continue so long as there is 2-PG 301 in the well. [0190] Step 352. The first tethered enzyme TET-PK 303 will take up the PEP 311 from step 351 and ADP 302 pre-seeded in the well/zone to produce Adenosine Triphosphate (ATP) 312. The ATP 312 is released into the well/zone where step 352 will continue for the needed measurable time period as long as there is PEP 311 from step 351 and ADP 302 in the well. [0191] Step 353. The second tethered enzyme TET-Luciferase 305 will take up the ATP 312 and Luciferin 304 pre-seeded in the well to produce luminescence (a light output signal) 315 with one photon per ATP 312 molecule. Step 353 will continue for the needed measurable time period as long as there is ATP 312 from step 352 and luciferin 302 in the well.
[0192] With each molecule of the NSE biomarker capable of performing at least hundreds of reactions per second, and each nanobot having hundreds to thousands of enzymes tethered to each silica (SiO.sub.2) nanoparticle, with an immobilization and enzyme orientation designed to optimize enzyme stability and activity in coupled enzyme reactions, and each of these hundreds to thousands of enzymes producing the reactions of steps 352 or 353, the overall signal production is extremely rapid. The total amount of signal is primarily limited by the amount of activity of the NSE-FA in the sample because no other substrates, co-factors or enzymes are present in limiting quantities for the desired assay time period that is typically less than 10 minutes and ideally less than 3 minutes. The embodiments of the present invention described in the remaining figures also allows excellent dynamic range of detection of the NSE-FA and the ability to directly assay the activity from plasma. While the preferred embodiment would use silica nanoparticles, it is envisioned that other nanoparticles would work so long as the nanoparticle material is transparent, translucent or reflective. For example, such nanoparticles would include:
[0193] Polycarbonate, acrylics such as Lucite, diamond, ceramics, other polymers, silver, gold and platinum. While nanoparticles typically range in size from 1 nm to 500 nm, it is also envisioned that other sized or non spherical particles may be used.
[0194] While the preferred embodiment uses nanoparticles that are approximately spherical, it is envisioned that embodiments using other shapes are possible including the following shapes: [0195] a. Cylindrical including nanowires, [0196] b. Mesoporous, [0197] c. Plates, [0198] d. Oblate spheroids, and [0199] e. Other heterogeneous shapes.
including beads, solid rods or other surfaces, or shapes extending from a surface could be used to stabilize the tethered enzymes.
[0200] FIG. 3C is a block diagram of an embodiment of the present invention method 380 to measure liver enzymes ALT and/or AST directly from plasma or serum using embodiments of the present invention tethered enzyme technology. The method 380 begins with step 382 where a blood sample is placed into a vial or container into which freeze dried uric acid and uricase have been added. In a preferred embodiment, the vial has the freeze-dried materials attached to a portion of the inner surface of the vial that is sealed and packaged in preparation for future use. In an alternate embodiment, powder or a tablet containing uric acid and uricase can be separately added to the vial. In other embodiments, the vial would be a vacutainer. In another preferred embodiment, the uricase is in the form of a tethered enzyme where the tethering may be either to the surface of the vial or to another surface such as that of a silica nanoparticle.
[0201] Next in step 383 the blood is converted to serum or plasma. In a preferred embodiment it is envisioned that step 383 could be done first where the blood is converted to serum or plasma before it is placed in the vial with uric acid and uricase.
[0202] Next in step 384, the serum or plasma from steps 382 and 383 is placed or flowed into one or more test reaction wells or zones having the materials described in FIGS. 1 and 2 for the liver enzymes ALT and/or AST. A portion of the plasma or serum would also be placed in one or more negative control wells or zones where one or more of the initial substrates SA1 111 and SA2 112 shown in FIG. 2 are absent. Finally, a third portion of the plasma or serum would be placed or flowed into one or more positive control wells or zones with the same components as the test wells/zones but also including a pre-seeded amount of the enzyme biomarker (e.g., ALT and/or AST).
[0203] While the preferred embodiment uses positive and negative control reactions, it is also envisioned that embodiments of low range and high range reactions could be used.
[0204] Next in step 385, the luminescence is measured from all the wells/zones and;
[0205] In step 386 the level of active ALT and/or AST is computed based on the luminescence measured from the test, positive and negative control wells/zones (e.g., as described with FIGS. 11A, 11B and 11C).
[0206] Finally in step 388, the quantitative measurement of ALT and/or AST activity is reported out and may include a display of the normal range of measurement of each.
[0207] FIG. 4A is a schematic view of an embodiment of the present invention custom assay strip 400 with 12 wells 402, having tapered (chamfered or filleted) entry 403 with an alignment notch 401 and lip 403. The notch 401 and lip 403 provide guides for placing the 12-well strip into a standard plate reader holder so that the left to right orientation of the wells is proper as the contents of the wells may differ. Specifically, if test wells, as well as negative and positive control wells are used in a non-symmetric layout, the proper orientation of the strip 400 is critical to interpret results. Note that in preferred embodiments for a luminescence readout, these 12-well strips crafted individually or produced as a portion of a 96-well plate, would be made of a white or reflecting materials so that more photons will leave the well and be captured by a plate reader or photodiode-based device. The image in FIG. 4A is shaded to provide easier viewing.
[0208] FIG. 4B is a longitudinal cross sectional view of a portion of a three layer component embodiment of the 12-well strip 400 of FIG. 4A showing a test well 402T, a positive control well 402P and a negative control well 402N, each well having a tapered entry 403 and a well volume 420, a curved bottom 410 and underside inset 425 to reduce the amount of plastic needed. The test well 402T has two layers of freeze-dried components 421 and 422 while the positive control well has three layers 421, 422 and 423. The negative control well 402N has only one layer 421. The layer 423 would include a pre-set amount of the biomarker being assayed with examples being an enolase for the NSE-FA assay and ALT or AST for the assays of liver enzymes. The positive control is key to the ability to quantify the enzymatic activity of the biomarker in the patient sample being assayed.
[0209] In a preferred embodiment where the biomarker is an enzyme, layer 423 would include the biomarker tethered to silica nanoparticles.
[0210] In an embodiment, the 12-well strip 400 would have at least one set of the three wells shown with alternate embodiments of 2 sets, 3 sets or 4 sets. It is also envisioned that other combinations such as one negative control 402N, three positive control wells 402P and three test wells 402T can be used.
[0211] In the embodiment where the strip 400 is used for the assay for functionally active NSE-FA shown in FIGS. 3A and 3B, an embodiment is to have the layer 421 include all the components shown in FIG. 2A except the 2-PG substrate 301. The layer 421 is placed in all the wells including test well 402T, negative control well 402N and positive control well 402P. During manufacturing, the layer 421 is placed into the well and then frozen.
[0212] For the NSE-FA embodiment of the strip 400 of FIG. 4B, the layer 422 would include the substrate 2-PG 301 of FIG. 3A and would be placed on top of the frozen layer 421 in the test wells 402T and positive control wells 402P but not the negative control wells 402N. Once inserted this layer would also be frozen. The layer 423 for the NSE-FA assay would include a pre-set amount of an active enolase and would be placed only in the positive control wells 402P and quickly frozen to prevent reaction with the frozen 2-PG in layer 422.
[0213] In a preferred embodiment one or more 12-well strips 400 would be placed on a freezer block to maintain the frozen state of the components when layers 422 and 423 are added. In a preferred embodiment, the freezer block such as the freezer block 490 of FIG. 10A would be designed to hold eight strips either individually or in a separate holder.
[0214] After all layers are deposited and then frozen, the strip(s) 400 are placed in a lyophilizer to freeze dry the strip(s) 400 that are then sealed in a light blocking and moisture resistant pouch that may optionally include a desiccant as any water that reaches the positive control well 402P could trigger premature reaction.
[0215] In an alternate embodiment to the layers 421, 422 and 423 may be placed in the wells in a different order with the biomarker (e.g. enolase) layer 423 placed first in the positive control wells, the primary component group 421 without 2-PG 301 placed next in all wells and the 2-PG 301 layer 422 placed last in the treatment wells 402T and positive control wells 402P. FIG. 7 describes a preferred embodiment of the process for laying down the layers to prevent inadvertent reaction.
[0216] It is also envisioned that if a fourth type of well being a second type of negative control well is used, then there would be three sets of four wells. An embodiment of such an added negative control is having a test well that includes a suppressant for NSE-FA but will still react to other forms of enolase from other sources including hemolysis.
[0217] FIG. 4C is a cross sectional view of a two layer preferred embodiment of the present invention coupled enzyme assay showing the shape of three wells of a 12-well strip 450 with positive control well 452P, test well 452T and negative control well 452N. Each well having a tapered entry 453, a tapered upper well 459, a well volume 460 and a curved well bottom 470. The positive control well 452P has two layers of freeze-dried components 462 and 463. The test well 452T, similar to the test well 402T of FIG. 4B, has two layers of freeze dried components 461 and 463 while the negative control well 452N, similar to the negative control well 402N of FIG. 4B, has only one layer 461. The advantage of a tapered well top 459 is to better allow for mold release without use of chemicals.
[0218] In the embodiment where the strip 450 is used for the assay for functionally active NSE-FA described in FIGS. 3A and 3B, a preferred embodiment is to have the layer 461 include all the components shown in FIG. 2A except the 2-PG substrate 301. Layer 461 is placed in test wells 452T and negative control wells 452N.
[0219] In the embodiment where the strip 450 is used for the assay for ALT or AST described in FIG. 3C, a preferred embodiment is to have the layer 461 include the components Luminol and L-Alanine for ALT and Luminal and L-Aspartate for AST. Layer 461 is placed in test wells 452T and negative control wells 452N.
[0220] The layer 462 in the positive control wells would include the components in layer 461 plus a preset amount of the biomarker desired (e.g. an Enolase for the NSE-FA Assay, ALT or AST for liver enzyme assays). Layer 462 would be placed as a first layer of each positive control wells 452P. In a preferred embodiment where the biomarker is an enzyme, layer 462 would include the biomarker tethered to silica nanoparticles. For the NSE-FA embodiment the layer 423 would include an enolase tethered to silica nanoparticles.
[0221] After the first layer (461 or 462) is deposited, the entire strip 450 is placed in a freezer for a specified time between 1 and 30 minutes in a ?15? to ?100? C. freezer, with a preferred embodiment being for at least 15 minutes in a less than ?70? C. (e.g. a ?80? C.) freezer.
[0222] In a preferred embodiment, eight strips would be placed into a multi-strip holder, layers 461 and 462 would be placed into in the wells at temperatures between 4? C. and 25? C. then a freezer block described (e.g., 490 of FIGS. 9B, 9C, 10A and 10B) would be removed from a freezer and the multi-strip holder (e.g., 485 of FIG. 8) with the strips 450 would be placed onto the freezer block 490 and frozen at ?15? to ?100? C. for 5 to 30 minutes with a preferred embodiment being for at least 15 minutes in a less than ?70? C. (e.g. a ?80? C.) freezer.
[0223] After removing the frozen strip(s) 450 from the freezer, the second layer 463 is placed on top of the frozen first layer 461 in the test wells 452T and on top of the frozen first layer 462 of the positive control well(s) 452P but not the layer 461 of the negative control well(s) 452N. Once deposited, layer 463 would then be frozen for a specified time between 1 and 30 minutes in a ?15? to ?100? C. freezer, with a embodiment being for at least 15 minutes in a less than ?70? C. (e.g. a ?80? C.) freezer.
[0224] For the embodiment for NSE-FA, layer 463 would include the substrate 2-PG of FIGS. 3A and 3B as well as buffers and cryoprotectants. For the embodiment for ALT and AST the layer 463 would include the substrate ?-ketoglutarate as well as buffers and cryoprotectants.
[0225] After all layers are deposited and then frozen, the strip(s) 450 are placed in a lyophilizer to freeze dry the strip(s) 450 that are then sealed in a light blocking and moisture resistant pouch that may optionally include a desiccant as any water that reaches the positive control well 452P could trigger premature reaction.
[0226] In a preferred embodiment where the biomarker is an enzyme, layer 462 would include the biomarker tethered to silica nanoparticles. For the NSE-FA embodiment the layer 462 would include an enolase tethered to silica nanoparticles.
[0227] In an alternate embodiment the layers may be placed in the wells in a different order with the layer 463 placed first in the positive control well(s) 452P and test well(s) 452T and the strip frozen. Then the layer 462 of the positive control well(s) 452P and the layer 461 of the test and negative control wells 452T and 452N would be added.
[0228] While the layers can be reversed, a preferred embodiment of the present invention has layer 463 that includes the substrates with which the enzyme biomarker reacts on top of the base layers 462 and 461 so layer 463 is that the first layer contacted when the sample is placed in the well. This facilitates a faster reaction start up allowing for better and quicker separation of the luminescence curves the test and positive control reactions.
[0229] FIG. 5 is a block diagram of a preferred embodiment of the enzyme production process 50 using an expression system (e.g. bacteria) to produce enzymes designed for tethering. [0230] The process begins by identification in step 51 of the specific gene that encodes expression by bacteria of the desired enzyme with affinity tags for tethering. [0231] The gene in fusion with affinity tags to allow tethering as shown in FIG. 6 and purification in step 56 is synthesized in step 52, for example, using a DNA synthesizer. [0232] Next one inserts in step 53 the gene with one or more affinity tags into an expression plasmid/vector. [0233] Next, one inserts the expression plasmid in step 54 into a protein expression system. Examples of expression systems include bacteria, insect cells, mammalian cells, yeast or other known expression systems. Bacteria are used in the preferred embodiment of the process 50. [0234] Next in step 55 the bacteria are induced to produce/express the desired enzyme including the desired affinity fusion tags. [0235] The final step is the purification process 56 that is used to separate other materials from the desired enzymes.
[0236] FIG. 6 is a block diagram of an embodiment of the enzyme tethering process 60 where active enzymes are tethered to nanoparticles (e.g., silica (SiO.sub.2) nanoparticles) using oriented immobilization that increases the stability and activity of the enzymes to facilitate improved shelf life and faster reaction times than can be achieved with non-oriented enzymes. This novel process produces an oriented immobilization that improves substrate access to the substrate-binding site/active site of each enzyme molecule and/or enables improved conformational changes or movements, and/or improves substrate channeling to a subsequent reaction step. The tethering process 60 follows enzyme purification step 56 of the Enzyme Production Process 50 of FIG. 5 as follows: [0237] The process begins in step 61 by cooling the nanoparticles in a vessel to a temperature between 1 and 10 degrees Celsius. [0238] Next in step 62, the purified enzymes with the affinity tags are added to the vessel. [0239] Next in step 63 the cooled vessel is allowed to incubate for a pre-set period of time. For example a period of 15 to 60 minutes may be used. [0240] Next in step 64 while still cooled, the incubated mixture is washed to remove un-tethered enzymes. For example, the nanoparticles are spun down using a centrifuge to the bottom of the vessel and the remaining liquid is replaced with a buffer such as phosphate buffer. This is repeated 1 to 5 times. In a preferred embodiment, the spin-down speed should for example be between 300 g to 1000 g. In some cases, 2 or more different enzymes may be combined in step 62 where it is desired that more than one type of enzyme is tethered to each nanoparticle. It is also envisioned that one can control the number of enzymes per nanoparticle by controlling the amount of enzymes added in step 62 relative to the size, number and concentration of nanoparticles. [0241] In the final step 65, stabilizers are added to the tethered nanoparticles. For example, suitable stabilizers include sorbitol, dextran, polyethelyne glycol or trehalose, among others.
[0242] It is envisioned that nanoparticles with other composition (other than silica) or other structures may also be used with the tethering process 60 to provide a surface for tethering enzymes.
[0243] FIG. 7 is a block diagram of an example of a preferred embodiment of the production process 10 for the assay strips 400 of FIG. 4A, including the steps for inserting the materials that are placed into the wells/zones for the present invention TET coupled enzyme assay 100 of FIG. 1. Such an assay is designed to receive a sample that may include the enzyme biomarker being assayed and can be read using standard lab plate readers (e.g., the TECAN Infinite 200 PRO), a photodiode based reader as shown in FIGS. 15 and 16, or by a reader integrated into a TET-PoC point of care assay device as shown in FIG. 19. A preferred embodiment of the mixture 13, mixture 14 and mixture 15 of FIG. 7 form respectively the layers 461, 462 and 463 of FIG. 4C.
[0244] A preferred embodiment of the present invention TET coupled enzyme assay would include at least one test well or zone, at least one positive control well or zone and at least one negative control well or zone.
[0245] A preferred embodiment of the present invention production process 10 to produce the strip 450 of FIG. 4C begins with sub-process 1 where a preferred embodiment process is performed at 4 degrees Centigrade comprising the following steps [0246] 1. The first step is the enzyme production process 50 of FIG. 5; [0247] 2. Next is the enzyme tethering process 60 of FIG. 6; [0248] 3. The tethered enzymes are then added in step 1-3 to the other materials including buffers, cryoprotectants and the substrates SB3, and SC3 shown in FIG. 1. These together form mixture 13 being the mixture used as the only layer for the negative control well(s) and the base layer for the test well(s) (e.g. layer 421 of FIG. 4B or layer 461 of FIG. 4C). Examples of the buffers and cryoprotectants include sorbitol, dextran, trehalose, glycerol; potassium ions, magnesium ions, phosphate ions, sodium Ions and/or PEG. For an embodiment of the NSE-FA assay of FIG. 3A, mixture 13 includes ADP (SB3) and luciferin (SC3) but does not include SA1 the primary initial substrate 2-PG needed to start the coupled enzyme reaction once in contact with a patient sample having NSE-FA. [0249] 4. Next in step 1-4 a portion of mixture 13 is added to a quantified amount of the biomarker being assayed to form Mixture 14. This is the base layer 462 of FIG. 4C for the positive control well(s). For the NSE-FA assay, the quantified biomarker added is an enolase that in a preferred embodiment may be tethered. [0250] 5. At this point, once mixtures 13 and 14 are ready, in step 1-5 a pre-set quantity of the negative control mixture 13 is inserted as layer 461 into the test well(s) 452T and negative control well(s) 452N of FIG. 4C. [0251] 6. This is followed in step 1-6 where the mixture 14 is inserted as Layer 462 into the positive control well(s) 452P of FIG. 4C or zone(s) completing sub-process 1.
[0252] Sub-process 1 is followed by sub-process 2 with steps as follows: [0253] 1. First in sub-process 2-1 a freezer block (e.g., the freezer block 490 shown in FIGS. 10A and 10B), is placed in a freezer for at least X hours at ?D degrees centigrade. The freezer block 490for example might be a piece of aluminum adapted to hold one or more strips 400 of FIGS. 4A-4C or blood separation chromatography strips (e.g., the strips 900 of FIG. 12A. In a preferred embodiment, X is typically more than 6 hours and D is less than ?15 degrees centigrade with a preferred embodiment being 24 hours and less than ?70 degrees centigrade (e.g. a ?80? C. freezer). [0254] 2. Next in step 2-2 the freezer block is removed from the freezer and the strips prepared with negative control, test and positive control first layers (e.g., layer 461 and 462 of FIG. 4C) are placed in contact with the freezer block. In a preferred embodiment up to eight 12-well strips are in a holder (e.g., the holder 485 in FIG. 8 for the 8 IVD strip 400 of FIG. 4A). [0255] 3. Next in step 2-3, the freezer block with strips is placed back in a freezer for Y minutes below E degrees centigrade. In one embodiment Y is more than 10 minutes and E is ?15 degrees centigrade. In a preferred embodiment, Y is 20 minutes and E is ?70 degrees centigrade (e.g. a ?80? C. freezer). This completes sub-process 2.
[0256] The final sub-process 3 in the preferred embodiment for in the production of the present invention coupled enzyme assay comprises the steps as follows: [0257] 1. Once the first layers (e.g. 461 or 462 of FIG. 4C) are fully frozen and the strip(s) are still in contact with the freezer block, in step 3-1 of sub-process 3, Mixture 15 is inserted to form layer 463 of FIG. 4C for the positive control well(s) 452P and the test well(s) 452T of FIG. 4C. Mixture 15 includes the substrate(s) that will react with the enzyme biomarker being assayed to begin the reaction ending in a signal output (e.g. the production of luminescence). For the NSE-FA assay, Mixture 15 would include 2-PG. For liver enzymes ALT and AST, Mixture 15 would include ?-ketoglutarate. Mixture 15 may also include buffers and cryoprotectants (e.g. sorbitol, dextran, trehalose, glycerol and PEG). [0258] 2. Next in step 3-2, the freezer block with the complete formulation for the assay wells or zones, is placed back in the freezer for Z minutes at below F degrees centigrade. In an embodiment Z may more than 10 minutes and F is ?15 degrees Centigrade. In a preferred embodiment, Z is 20 minutes and F is ?70 degrees centigrade (e.g. a ?80? C. freezer). [0259] 3. Next, in step 3-3, the strip(s) 450 of FIG. 4C with the fully frozen complete formulation of test well(s) 452T, negative control well(s) 452N and positive control well(s) 452P, is placed in a freeze dryer to remove all water or other liquid in the well(s) that could allow the positive control well(s) to begin reacting without the addition of the patient liquid sample(s) to be tested. [0260] 4. The final step 3-4 is to remove the strips from the freeze dryer in a low humidity environment and package them in a sealed pouch. In a preferred embodiment a desiccant is placed in the pouch to ensure that no moisture reaches the well(s).
[0261] It is also envisioned that the positive control well(s) could be prepared with only the end stage substrates SC3 113 and SC1 131 needed for activation of the signaling tethered enzyme TE2 130 of FIG. 1. For the NSE-FA coupled enzyme assay, this would have the positive control with a first layer including tethered luciferase and luciferin and a second layer with a pre-set quantity of Adenosine Tri-Phosphate (ATP). Similarly, a positive control with the first layer being the composition of the negative control layer 461 of FIG. 4C with a second layer including a pre-set amount of the substrate SB1 121 of FIG. 1 that would be Phosphoenolpyruvate (PEP) for the NSE-FA assay.
[0262] It is also envisioned that there could be two or more positive control types with one with the amount of the biomarker (e.g., enolase) at the threshold for brain injury and one at say ten times that to provide calibration and enhance quantification between the two levels.
[0263] In another embodiment, the positive control well(s) can be replaced by previously-obtained, temperature-dependent luminescence data recorded from positive controls, or the TET-IVD strip could include an LED that provides a light output over time that may be temperature adjusted to emulate the result that is seen by recorded positive control wells when activated. It is also envisioned that the recorded signal from a positive well could be stored in the TET-PoC memory and no positive well(s) would be needed.
[0264] In another embodiment for the point of care TET-PoC NSE-FA assay with electrical voltage signal output, the tethered luciferase (LUC-NP) is replaced by the enzyme Pyruvate Oxidase tethered to silica nanoparticles (PYROX-NP), for preparation of the test wells, and positive control and negative control wells, otherwise the multi-step process is highly similar.
[0265] In another embodiment for electrical signal output Pyruvate Oxidase would be tethered directly onto an electrode (preferably silver or gold). the Si-tag will be replaced with Ag-tag or Au-tag.
[0266] In another embodiment, The Pyruvate Oxidase will be tethered to SiO.sub.2 nanoparticles or to an electrode, and HRP will be immobilized onto an electrode (using e.g., Au or Ag tags). It is also envisioned that cofactors FAD and TDP could be added (but not required).
[0267] While it is possible to produce 1 strip at a time, this is not practical for the size and scope of the unmet need for the advanced assays possible with the present invention. The next figures and description will describe a production method to produce multiple strips efficiently for commercial or clinical applications. This technique is also applicable to production with an automated or semi-automated injection system such as the Opentrons OT-2 Workstation.
[0268] FIG. 8 shows a top view of a preferred embodiment of a production module 480 being a standard 96-well, 8-strip holder 485 with eight empty 12-well strips 411 though 418. The benefit of the holder 485 is that it allows easy handing during production of eight strips at a time and similarly is designed to be used in standard medical fluid handling devices for production, testing and also in the final use with one or more strips in a medical testing lab. It is also envisioned that embodiments of the present invention can function with as few as 3 wells (i.e., a test well, a positive control well and a negative control well). Thus while the holder 485 shows eight 12-well strips, it could instead hold sixteen 6-well strips or thirty-two 3-well strips.
[0269] Note that strips can be manufactured in various configurations (e.g., one or more negative control wells in a row, followed by one or more test wells in a row, followed by one or more positive control wells in a row; or one or more test wells, followed by one or more negative controls, followed by one or more positive controls, etc.). FIG. 9A is a top view of the production module 480A with holder 485 with the eight strips 411A-418A after layer 461 of FIG. 4C has been deposited into the test and negative control wells. Here, for illustrative purposes, we show a pattern of one positive control well, followed by one test well, followed by one negative control well, with this triplet pattern repeating four times in a 12-well strip. Specifically in strip 411A, Layer 461 of FIG. 4C is shown in the four test wells 411AT1, 411AT2, 411AT3 and 411AT4 and four negative control wells 411AN1, 411AN2, 411AN3 and 411AN4. The positive control wells 411AP1, 411AP2, 411AP3 and 411AP4 are still empty at this stage. There are similar deposits in the test and negative control wells for the other 7 strips 412A through 418A.
[0270] FIG. 9B is a top view of the production module 480B with holder 485 with the eight strips 411B-418B after completion of sub-process 1 of FIG. 7 where Layer 462 of FIG. 4C has been deposited into the positive control wells. Specifically in strip 411A, Layer 462 of FIG. 4C is shown in the four positive control wells 411AP1, 411AP2, 411AP3 and 411AP4. There are similar deposits in the positive control wells for the other seven strips 412B through 418B. Up to this point, the process can be performed at temperatures between 4 degrees C. up to room temperature.
[0271] FIG. 9B is a top view of the production module 480B with holder 485 with eight strips 411B-418B as it would be after step 2-2 of sub-process 2 of FIG. 7 where the production module 480B is placed in a rectangular depression 495 in the top of the freezer block 490 after the freezer block 490 has been removed from a freezer (not shown) after step 2-1 of FIG. 7. In this configuration, the production module 480B with the holder 485 and freezer block 490 is re-inserted into a freezer for Y minutes at E degrees C. as shown in step 2-3 of FIG. 7.
[0272] FIG. 9C is a top view of the production module 480C with holder 485 with eight strips 411C-418C on the freezer block 490 as it would be after completed step 3-1 of sub-process 3 of FIG. 7 where the production module 480B including the freezer block 490 has been removed from the freezer completing sub-process 2 and has then received the final Layer 463 of FIG. 4C where mixture 15 of FIG. 7 has been deposited into the positive control and test well. Specifically in strip 411C, Layer 463 is shown in the four positive control wells 411CP1, 411CP2, 411CP3 and 411CP4 and four test wells 411CT1, 411CT2, 411CT3 and 411CT4. The four negative control wells are skipped in this step. In this configuration, the production module 480C with freezer block 490 is re-inserted again into the freezer for Z minutes at F degrees C. as shown by step 3-2 of FIG. 7.
[0273] FIG. 9D is a top view of the configuration of the completed production module 480D after steps 3-2 and 3-3 of FIG. 7, now removed from the freezer block 490 of FIG. 9C and cycled through a freeze dryer to lyophilize the contents of the wells. In this configuration, the holder 485 and eight strips 411D-418D have been removed from the freezer block 490 in a low humidity environment and are ready for removal from the holder 485 and insertion and sealing into light and moisture proof pouches. In a preferred embodiment a desiccant pack/module is inserted into the pouch enclosing the freeze dried strip to ensure no moisture reaches the positive control wells, that will begin to react once wet.
[0274] In this configuration, there are four positive control wells, four test wells and four negative control wells ready for use with samples from a patient. For example, for strip 411D, the wells 411DP1, 411DP2, 411DP3 and 411DP4 are positive control wells, the wells 411DT1, 411DT2, 411DT3 and 411DT4 are test wells and the wells 411DN1, 411DN2, 411DN3 and 411DN4 are negative control wells.
[0275] The embodiment of FIG. 9D shows the 12 well configuration of PTNPTNPTNPTN where P is a positive control well, T is a test well and N is a negative control well. It is also envisioned that other embodiments of different orders of wells would be viable including NNNNTTTTPPPP, TTTTPPPPNNNN, PPPPTTTTNNNN as well as TTPPNNTTPPNN etc. Also if 3, 6 or 9 wells are needed layout embodiments are envisioned such as NNTTPP, PPTTNN PTNPTN, NNNTTTPPP, PPPTTTNNN, PTNPTNPTN etc. It is also envisioned that using the test well without either or both positive and negative controls could be functional.
[0276] FIG. 10A is a schematic view of the freezer block 490 with depression 495 placed on top of an insulating pad 500 with pedestals 502 to limit the heat flow from the insulating pad to the freezer block 490 so it will remain at a cold temperature during sub-process 3 of FIG. 7 when layer 463 of FIG. 4C is added. This will ensure that layer 462 of FIG. 4C of the positive control wells will remain frozen and not start the reaction as the liquid of layer 463 is placed on top of layer 462. The freezer block 490 includes slots 496 and 497 to allow insertion of a handle 499 of FIG. 10B to facilitate moving the freezer block into and out of the freezer and freeze dryer during sub-process 2 and sub process 3 of FIG. 7. It is envisioned that other embodiments of the handle could work including detents on the side of the freezer block 490 to allow a separate tongs to lift from above or a permanent rotatable handle that would rotate to the side lying flat during production and be rotatable to a position to allow the block 490 to be grabbed with gloves.
[0277] FIG. 10B is a schematic view of the Freezer block 490 with the handle 499 inserted into the slots 496 and 497. Ideally the handle 499 is made of a material with low thermal conductivity such as wood or plastic. This is of particular importance if a very low temperature freezer (e.g. a ?80? C. freezer) is used in sub-processes 2 and 3 of FIG. 7.
[0278] In a preferred embodiment where the freezer block 490 is used with a multi-pipetting robot like the Opentrons Flex OT-2 Workstation, the insulating pad 500 would be sized to fit in the opening for a standard 96 well plate and fit into a recess (not shown) in the bottom of the freezer block 490 to ensure alignment of the recess 495 with the recess in the base of the robot that ensures accurate pipetting of fluids into the wells shown in FIGS. 9A through 9C.
[0279] It is also envisioned that a larger freezer block designed to hold multiple production modules 480 of FIG. 8 could be produced to facilitate production of multiple sets of eight 12-well strips (or sixteen 4 well strips etc.) during each stage of the sub-processes 1 and 3 of FIG. 7
[0280] FIG. 11A is a graph showing an example of the luminescence data over time from a 12-well strip over ten minutes. Each dot represents the amplitude of the luminescence from one of the 12 wells being the number of photons detected from the well by a detection device (e.g. a plate reader) during the half second measurement period used to sequentially measure each well. For this example, the TET coupled enzyme assay strip (e.g., the strip 400 of FIG. 4A) has four sets of three wells along its length of with each set having a test well (e.g., the well 452T in FIG. 4C), a positive control well (e.g., the well 452P of FIG. 4C), and a negative control well (e.g., the well 452N of FIG. 4C). When placed into a standard plate reader such as the Tecan Infinite 200 PRO, each of the strip's 12 wells has its luminescence measured in turn again and again with all 12 wells read every 10 seconds for a 10 minute duration period by the light detector (e.g., a photomultiplier tube) in the plate reader.
[0281] Each dot represents the number of photons detected over the pre-set time period (e.g. 0.5 seconds) and with different shades of dots for each of the 12 wells as follows: [0282] 811L, 812L, 813L and 814L representing the luminescence from each of the four positive control wells, [0283] 821L, 822L, 823L and 824L representing the luminescence from each of the four test wells, [0284] 831L, 832L, 833L and 834L representing the luminescence from each of the four negative control wells.
[0285] The kinetics of the luminescence produced by the coupled enzyme assays of the present invention embodiments are such that the activity of the enzyme in the sample (e.g., NSE, ALT or AST) will be approximately proportional to the rate of the luminescence photon production (given as LU) per second. The rate of the light output (luminescence) is determined by the slope of each of the N, T, and P traces, with units of Luminescence Units (LU) per Second (LU/Sec).
[0286] Plate readers (e.g., the TECAN Infinite 200 Pro) include software that can calculate a linear slope from the data collected for each well's luminescence over a measurement portion of the duration period (e.g., 10 minutes in FIG. 11A). It is envisioned that this measurement period can be as short as 30 seconds and as long as 30 minutes with a preferred embodiment being 2-5 minutes. In a preferred embodiment, one would start the measurement period with an optional brief, pre-determined delay after the start of the assay, which commences upon addition of the fluid sample to the test, positive and negative control wells and insertion into the plate reader. For example, a 2 minute measurement period could begin 30 seconds after the start of the duration period.
[0287] FIG. 11A shows the 12 slopes calculated for each of the 12 wells and three average slopes as: [0288] 811S, 812S, 813S and 814S representing the luminescence slopes from each of the 4 positive control wells, [0289] 821S, 822S, 823S and 824S representing the luminescence slopes from each of the 4 test wells, [0290] 831S, 832S, 833S and 834S representing the luminescence slopes from each of the 4 negative control wells. [0291] average slope for the four positive control wells 815(S.sub.P), [0292] average slope for the four test wells 825(S.sub.T) and [0293] average slope for the four negative control wells 835(S.sub.N).
[0294] In a preferred embodiment the average slopes 815(S.sub.P), 825(S.sub.T) and 835(S.sub.N are used by the plate reader to calculate the relative activity of the enzyme (e.g., NSE-FA) in the sample.
[0295] To understand how this works one begins with the contributions to the luminescence for each type of well. It is also important to note that the rate of the enzymatic activity in the coupled enzyme reaction of embodiments of the present invention is approximately proportional to the slope of the luminescence curve during a period of M minutes of the reaction before saturation effects occur. In embodiments, M may be between 1 and 30 minutes that optionally may start after a short delay. While the total kinetics of a coupled enzyme assay like that of the present invention are influenced by the various rates of activities of each enzyme, and subject to influences of changing concentrations of reaction products, substrates and cofactors, for the sake of simplicity here, the methods described herein are envisioned as a viable technique to reproducibly determine the activity of the enzyme biomarker E1 of FIG. 1.
[0296] Specifically: [0297] 1. Luminescence from a negative control well will be produced from any molecule in the blood that could activate either tethered enzyme in the coupled enzyme reaction or react with luciferin. As the initial substrates for the biomarker enzyme being assayed is missing, the luminescence data seen from the negative control wells 831L, 832L, 833L, and 834L will be the base luminescence of the test and positive control wells. If this is too high, it may signal an error condition that would require a re-test for example. In embodiments of the present invention, means to identify error conditions from the negative control data are envisioned, [0298] 2. Luminescence from a test well will equal that of luminescence from a negative control well plus the luminescence produced by the reaction of the substrates SA1 and SA2 with the active Enzyme E1 of FIG. 1. Thus the normalized value of the activity of the Enzyme E1 sample pipetted into a test well(s) S.sub.TR can be calculated by subtracting the luminescence slope S.sub.N of the negative control well(s) from S.sub.T of the test well(s). [0299] 3. Luminescence from a positive control well will include the luminescence from a test well (2 above) plus the luminescence produced by the additional enzyme pre-seeded in the test well in layer 462 of FIG. 4C. Thus the normalized value of the activity of the pre-seeded enzyme in layer 462 of FIG. 4C S.sub.PR can be calculated by subtracting the luminescence slope S.sub.T of the test wells from luminescence slope S.sub.P of the positive control well(s).
[0300] Mathematically, the Real luminescence slope S.sub.PR defined as the fraction of luminescence from only pre-seeded enzyme in the positive control well(s) (e.g., enolase for NSE-FA) can be calculated as:
S.sub.PR=S.sub.P?S.sub.T and
the Real luminescence slope S.sub.TR from the NSE-FA in the patient sample from the test wells defined as the fraction of luminescence from only the biomarker enzyme E1 of FIG. 1 in the sample added to the test well(s) can be calculated as:
[00001]
[0301] The values of S.sub.PR and S.sub.TR provide a means to not only measure the activity of the enzyme E1 of FIG. 1 in the patient sample (e.g., NSE-FA), but also provide a technique that can be used to set a threshold for setting a normal range for such activity (e.g., for significant brain injury for the NSE-FA coupled enzyme assay).
[0302] In a preferred embodiment, an Activity Level can be calculated where the Activity Level (A.sub.P) is S.sub.TR expressed as percentage of S.sub.PR i.e.
[00002]
[0303] In terms of the slopes from the measured luminescence traces, this would be
[00003]
[0304] It is also envisioned that a fraction A.sub.F may be used where A.sub.F=S.sub.TR/S.sub.PR.
[0305] In another embodiment, the positive control and test well luminescence slopes may be normalized to the negative control only and the negative control normalized activity may be represented as a percentage or fraction as:
[00004]
[0306] Whether a fraction or percentage, these normalized values of activity can be compared to a normal range of activity with lower bound A.sub.TL and upper bound Aru where detection of abnormal biomarker levels would be levels of activity below A.sub.TL or above A.sub.TU.
[0307] In other embodiments, the 12 slopes may be used to reduce variance by taking the median of the slopes instead of the average or by eliminating the high and low and averaging the two other slopes to get the average slopes S.sub.P, S.sub.T and S.sub.N.
[0308] In still other embodiments, the 12 slopes may be used to reduce variance by removing any one slope that differs by more than some percentage (e.g., 5%) from the other three values.
[0309] While the term amplitude for FIG. 11A represents the number of photons detected over a half second by the reader used, it is envisioned that it can also be used in embodiments to represent any measurement of the amount of luminescence from a well or zone including: [0310] 1. the voltage at a specific time or the average voltage from a photodiode or [0311] 2. a counted number of photons by a photo multiplier tube in a luminescence reader. [0312] 3. the output from a charge coupled device at a single point in time or averaged over to pre-set time period.
[0313] FIG. 11B is a graph showing an alternate algorithmic embodiment using the Area Under the Curve (AUC.sub.P, for the positive control wells, AUC.sub.T for the test wells and AUC.sub.N for the negative control wells) to measure luminescence data from a coupled enzyme reaction. Similar subtractive methods or other algorithms may be applied to these values over a preset duration period (e.g. ?10 minutes in FIG. 11B) to calculate the activity of the biomarker in the patient samples.
[0314] FIG. 11C is a graph showing an alternate algorithmic embodiment to measure luminescence data from a coupled enzyme reaction using the an average value of the luminescence (P.sub.P for the positive control wells, P.sub.T for the test wells and P.sub.N for the negative control wells) at point in time.
[0315] FIGS. 11B and 11C are alternatives to the scheme using slope described for FIG. 11A. These alternatives may be preferable for embodiments, for example, where the biomarker is a substrate and not an enzyme. These alternate embodiments of the present invention would include algorithms for measuring amounts of biomarker in a patient sample such as: [0316] Measurement based on the area under the curves (AUC) as shown in FIG. 11B. Here calculations would be based on the values of the areas under the curves for the positive controls AUC.sub.P, test wells AUC.sub.T and negative control wells AUC.sub.N. FIG. 11B uses 600 seconds for this calculation but a longer or shorter time may be utilized. The calculation of the Real luminescence from the sample pipetted into the test wells AUC.sub.TR and Real luminescence from the biomarker pre-seeded in the positive wells AUC.sub.PR can be calculated similarly to that shown in FIG. 11A where: AUC.sub.TR=AUC.sub.T?AUC.sub.N and AUC.sub.PR=AUC.sub.P?AUC.sub.T. The measured biomarker level can then be assessed as AUC.sub.TR as a percentage or fraction of AUC.sub.PR. [0317] Measurement based on the peak luminescence over a pre-set time period as shown in FIG. 11C (in this example, for a 10 minute (600 second) time period). Here a similar algorithm to that used for slopes on FIG. 11A or area under the curve for FIG. 11B can be implemented. For example, the calculation of the Real luminescence from the sample pipetted into the test wells P.sub.TR and Real luminescence from the biomarker pre-seeded in the positive wells P.sub.PR can be calculated similarly to that shown in FIG. 11A where: P.sub.TR=P.sub.T?P.sub.N and P.sub.PR=P.sub.P?P.sub.T. The measured biomarker level can then be assessed as P.sub.TR as a percentage or fraction of P.sub.PR.
[0318] Other viable envisioned embodiments would include using: [0319] The average of multiple activity measurements based on slope taken at a multiplicity of time points. [0320] Measurement of the second derivative of the luminescence data curves. [0321] Measurement of time to a peak value of luminescence. [0322] Various combinations of the above (for example Peak Luminescence X Slope)
[0323] FIGS. 12A, 12B, 12C and 12D show an embodiment of the top view of lateral flow blood separation filter paper embodiments of the present invention that would be applicable to a Point-of-Care (PoC) or home use assay using the present invention tethered enzyme technology. The configuration shown would be applicable to embodiments of assays for NSE-FA or liver enzyme ALT and AST activity as shown in FIGS. 1, 2, 3A, 3B and 3C.
[0324] FIG. 12A is a top view showing the blood separation paper strip set 900 with negative control strip 911, test strip 912 and positive control strip 913 as they might be configured before being used in a PoC diagnostic assay.
[0325] A preferred embodiment of the strip set 900 would have well reaction zones 961 and 962 of strips 911 and 912 including components similar to layer 461 of FIG. 4C, and zone 963 of positive control strip 913 including the components similar to layer 462 of FIG. 4C including a preset amount of the assayed biomarker. The band 921 of strips 912 and 913 would have components similar to layer 463 of FIG. 4C including the substrate on which the enzyme biomarker works (for example, 2-PG for the NSE-FA coupled enzyme assay shown in FIGS. 3A and 3B. Fluid input zone 919 in strips 911, 912 and 913 shows the location where whole blood is placed. In a preferred embodiment the fluid input zone 919 may include or be connected to a blood absorbing reservoir or physical barrier that can help prevent overflow if excess blood is placed onto the zone 19.
[0326] In preferred embodiments, the entire strip may be sealed or coated except for the fluid input zones 919. Examples of such coatings include plastic and paraffin. A small air vent (not shown) could be added below the zones 925 to ensure full flow of the plasma into and past the reaction zones 961, 962 and 963. It is envisioned that once the liquid blood/plasma is fully saturated in the paper strip it will stop flowing with plasma in the reaction zones 961, 962 and 963 each having approximately the same amount of plasma that can react to provide luminescence.
[0327] In an embodiment, the flow extension zones 925 of strips 911, 912 and 913 allow excess plasma to flow beyond the reaction zones 961-963, ensuring that each reaction zone has a standard and saturating volume that fills the paper in that zone, but which does not pool in excess.
[0328] Other embodiments are envisioned that have the N, T, and P reaction on a single lateral flow paper, separated by hydrophobic separators such as ink or wax based. Rather than side-by-side, another embodiment might have the 3 lateral flow papers stacked over each other, with separation layer including photodiodes between the papers.
[0329] FIG. 12B is a top view showing the strips 900 at a time of several seconds after a patient's blood has been placed in the fluid input zone 919 of the strip set 900. It shows the blood in area 950 of the test strips 911, 912 and 913. As the liquid flows away from the area 950, blood cells and cell fragments (e.g., platelets) are retained within the areas 950-951 and the remaining plasma 952 continues to flow down the strips 911, 912 and 913. As shown the plasma has just reached the bands 921.
[0330] FIG. 12C is a top view showing the assay strips 900 as the plasma 952 has now filled the reaction zones 961, 962 and 963 and is filling the flow extension zones 925 of the strips 911, 912 and 913 respectively. As shown, [0331] the plasma 952 of the negative control strip reached the negative control reaction zone 961; [0332] the plasma 952 of the reaction test strip has mixed with the band 921 bringing the reaction components and any products formed within the band 921 into the reaction test zone 962; and [0333] the plasma 952 of the positive control strip has mixed with the band 921 bringing the components and any products formed found in the band 921 into the reaction test zone 963.
[0334] The reaction zones 961, 962 and 963 will now produce luminescence that can be measured photometrically to provide the luminescence data such as that shown in FIG. 11A from which the activity of the enzyme E1 103 of FIG. 1 can be determined.
[0335] Examples for NSE-FA, ALT and AST of this preferred embodiment would have the following elements of FIG. 2 in the zones and bands of the strip set 900 as follows:
[0336] For NSE-FA, zones 961 and 962 would include the tethered enzymes Pyruvate Kinase (TET-PK) 303, tethered Luciferase (TET-Luciferase) 305 and the compounds ADP 302 and Luciferin 304 of FIG. 3A. The zone 963 would include the components in band 961 (or 962) plus a preset amount of enolase. In a preferred embodiment, the enolase would be tethered. The band 921 would include the substrate 2-PG 301 of FIG. 3A.
[0337] For ALT, zones 961 and 962 would include the tethered enzymes Glutamate Oxidase (TET-Glut-OX) and tethered Horse Radish Peroxidase (TET-HRP), and the compound Luminol shown in FIG. 2. The zone 963 would include the components in band 961 (or 962) plus a preset amount of the liver enzyme ALT. In a preferred embodiment, the ALT in zone 963 would be tethered. The band 921 would include the substrates ?-ketoglutarate and L-Alaninine shown in FIG. 2.
[0338] For AST, zones 961 and 962 would include the tethered enzymes Glutamate Oxidase (TET-Glut-OX) and tethered Horse Radish Peroxidase (TET-HRP), and the compound Luminol shown in FIG. 2. The zone 963 would include the components in band 961 (or 962) plus a preset amount of the liver enzyme AST. In a preferred embodiment, the AST in zone 963 would be tethered. The band 921 would include the substrates ?-ketoglutarate and L-Aspartate shown in FIG. 2.
[0339] In this embodiment pre-treatment of the blood or plasma with uricase (tethered or not) and uric acid is necessary for the ALT and AST luminescence coupled enzyme assays of the present invention. For liver enzyme use with the configuration of the strip set 900 of FIG. 12A, the blood would need be pre-treated before it is placed onto the strips 911, 912 and 913. In a preferred embodiment this pre-treatment uses freeze dried tethered uricase and uric acid placed into the blood collection vial from which blood is added to the strip set 900. This may be done by freeze drying the uric acid and uricase onto the inside surface of the vial or separately introducing them into the vial, for example by adding a tablet, or powder to the vial.
[0340] While it is possible to put all the components into the reaction zones 961, 962 and 963 using layering such as shown in FIG. 4C, an advantage of this preferred embodiment of the PoC assay is that the substrates with which the biomarker reacts in the band 921 are separated from the reaction zones 961, 962 and 963.
[0341] In embodiments of the present invention PoC coupled enzyme assay, it is envisioned that a single input of blood could be configured with the fluid input zones 919 of the negative control strip 911, test strip 912 and positive control strip 913 interconnected so that blood placed in the interconnected zone 919 would flow and be filtered into 3 or more blood filter/assay strips or channels such as the strips 900. Examples of this concept are shown in FIGS. 13A, 13B and 14.
[0342] For clarification, the term band such as the bands 921 of FIG. 12A refers to a collection of components meant to be picked up by fluid (e.g. plasma) flowing down the strips 912 and 913 such that those components are carried into the reaction zones 962 and 963 where they participate in any reaction producing assay luminescence. The reaction zones 961, 962 and 963 are the areas of the strips 911, 912 and 913 monitored by photon detection mechanisms adapted to measure the amplitude of the luminescence reaction occurring in each reaction zone.
[0343] FIG. 12D is a top view showing an alternate embodiment of the lateral flow blood separation assay paper strip set 950 with negative control strip 951, test strip 952 and positive control strip 953. In this embodiment, this negative control strip 951 is the same as the negative control strip 911 of FIG. 12A and the test strip 952 is the same as the test strip 912 of FIG. 12A. Specifically, the zone 971 is the same as the zone 961 of FIG. 12A, the zone 972 is the same as the zone 962 of FIG. 12A, the band 971 is the same as the band 921 of FIG. 12A and the area 975 is the same as the area 925 of FIG. 12A.
[0344] While the band 974 of the positive control strip 953 is the same as the band 921 of FIG. 12A, the positive control strip 953 differs in that the components in the zone 973 has the same components as the zones 971 and 972 and does not include a preset amount of biomarker as does the zone 963 of FIG. 12A. In this embodiment, the preset amount of biomarker is placed into band 922 that will release the biomarker into the flowing plasma as it flows down strip 953 similar to the flow of plasma in FIGS. 12B and 12C.
[0345] FIG. 12E is a top view showing the blood separation paper strip set 1200 for both liver enzymes ALT and AST with negative control strip 1211, ALT test strip 1212, ALT positive control strip 1213, AST test strip 1214 and AST positive control strip 1215 as they would be configured before being used in a PoC diagnostic assay.
[0346] The zones 1261, 1262 and 1264 include the tethered enzymes (see FIG. 2) TET-Glut-Ox, TET-HRP as well as Luminol for the ALT/AST liver tests. Zone 1263 also includes the pre-set amount of ALT (tethered or not) as the positive control for the ALT assay. Zone 1265 also includes a pre-set amount of AST (tethered or not) as the positive control for the AST assay.
[0347] The bands 1230 of strips 1212 and 1213 include ?-ketoglutarate and L-Alanine, the substrates with which ALT reacts. The bands 1240 of strips 1214 and 1215 include ?-ketoglutarate and L-Aspartate, the substrates with which AST reacts.
[0348] It is also envisioned that in embodiments, the positive control pre-set amounts can be in a separate band like the band 922 of FIG. 12D instead of in the zones 1263 and 1265 of FIG. 12E.
[0349] The embodiments of ALT and AST assays in FIG. 12E do not require separate pre-treatment of the blood in a separate vial but include the bands 1220 having uric acid and uricase (tethered or not) that will provide the pre-treatment as the blood and then plasma flow along the strips 1211 through 1215 so that the treatment will be completed before the plasma reaches the zones 1261 through 1265.
[0350] While the preferred embodiment of positive controls uses a preset amount of the biomarker being assayed (or an analog such as enolase for NSE), it is envisioned that alternate positive control formulations the include pre-set amounts of substrates/intermediates produced in later portions of the coupled enzyme reaction would function well. For example, for the NSE-FA assay, having a pre-set amount of phosphoenolpyruvate (PEP) made by NSE-FA or ATP could function rather than a preset amount of enolase.
[0351] It is envisioned that instead of the paper chromatography strips shown in FIGS. 12A through 12D, for the purposes of this specification, the present invention embodiments of fluid flow strips may include any fluid flow entity (with or without blood separation capability) selected from the group of: [0352] chromatography paper, [0353] microfluidic channels, [0354] membranes, [0355] matrices, or beads/particles/fibers [0356] any fluid flow entity in an enclosed space that will facilitate passive fluid flow (e.g., as achieved through capillary action), or active flow (e.g., as achieved with a pump).
[0357] For the purposes of this specification, the term test strip may represent any of the above types of fluid flow entity with a test zone designed to measure a biomarker, a positive control strip may represent any fluid flow entity that has a pre-set amount of the biomarker to allow the assay to quantify the amount of biomarker or biomarker activity in the sample, and the term negative control strip represents any fluid flow entity that can serve as a negative control for the present invention assay.
[0358] FIG. 13A is a schematic view showing an embodiment of a TET assay card 1200 configured for insertion into a photodiode-based reader. The assay card 1200 has a main body 1201, handle 1202 and assay structure 1250 having a fluid input zone 1210, blood separation strip 1221 and plasma flow structures 1215, 1216, and 1217 with 1215 connected to the test zone 1211T, 1216 connected to the negative control zone 1211N and 1217 connected to the positive control zone 1211P.
[0359] The plasma flow structures 1215 and 1217 have substrate bands 1231 similar to the bands 921 of FIG. 12A and the bands 974 of FIG. 12D. The plasma flow structure 1217 also has a positive control band 1232 has a preset amount of the biomarker being assayed similar to the band 922 of the positive control strip 953 of FIG. 12D. In this embodiment, the materials in zone 1211T are similar to that of zone 972 of FIG. 12D, the contents of the zone 1211N are similar to that of zone 971 if FIG. 12D and the contents of zone 1211P are the same as the that of zone 973 of FIG. 12D.
[0360] In a preferred embodiment, the band 1232 is missing and like the embodiment of FIG. 12A, the pre-set amount of biomarker is included in zone 1211P similar to that of zone 963 of FIG. 12A.
[0361] In this preferred embodiment where the positive control zone 1211P includes a pre-set amount of biomarker, the operation of the card 1200 is similar to that shown with the strip sets 900 and 900 of FIGS. 12B and 12C where blood cells and cell fragments are restrained within the blood separation strip 1221 allowing plasma to flow down the plasma flow structures 1215, 1216 and 1217 picking up materials in the substrate bands 1231 (test and positive controls only) and flowing into the reaction zones 1211T, 1211N and 1211P respectively.
[0362] In use, the card 1200 would be removed from its sealed and light proof pouch, blood from a finger prick or point of care collection device would be placed into the fluid input zone 1210 and the card 1200 held by the handle 1202 would be placed into a photodiode detection device where insertion would, in a preferred embodiment, activate or turn on the device that would then analyze the luminescence from the three reaction zones 1211T, 1211N and 1211P to provide a quantitative measurement of the biomarker and/or indicator of the test result as being one or more of: high, low and/or negative or positive.
[0363] For example, NSE-FA that exceeds a threshold would indicate significant acute brain injury that might be associated with a stroke or concussion. Note that the indicator could have various embodiments, including visual displays (e.g., text saying high versus normal, or one or more colored lights such as green for normal range values, versus red for high values), or an auditory indicator for values exceeding the threshold, or any combination thereof.
[0364] FIG. 13B is a top view showing an embodiment of a TET diagnostic PoC card layout 1300 where the fluid input zone 1320 is centrally located with 5 blood separation strips 1311, 1312, 1313, 1314 and 1315 leading to reaction zones 1301, 1302, 1303, 1304 and 1305 respectively. Substrate bands 1321, 1322, 1323 and 1324 can have components or function similar to that of the bands 921 of FIG. 12A.
[0365] Embodiments of the card 1300 could have any combination of test, positive control and negative control reaction zones; however, a preferred embodiment would have one negative control zone, one positive control zone and three test reaction zones.
[0366] In a preferred embodiment such as that for liver enzymes ALT and AST, one could have a configuration where the 5 strips would have similar function to the 5 strips of FIG. 12E with zone 1301 being the test zone for ALT, 1302 the positive control for ALT, 1303 being the test zone for AST, 1304 being the positive control zone for AST and 1305 being the negative control zone. This configuration would use the blood pre-treatment method in a collection vial of FIG. 3C. An alternate embodiment would include an added band or area for pre-treatment in or near the fluid input zone 1320.
[0367] FIG. 14 is a schematic view of an embodiment of a TET coupled enzyme assay test module 1400 where a blood sample volume 1450 is deposited into the upper cylinder 1420 with strip holder 1411 and 4 blood separation paper strips 1451, 1452, 1453 and not shown 1454 having fluid input zones 1481, 1482, 1483 and 1484 (not shown). The strip 1452 is the test strip with the substrate band 1462 and reaction zone 1472 similar to the strip 912 with band 921 and reaction zone 962 of FIG. 12A. In an embodiment, a valve 1404 with actuator 1406 would allow blood to be placed in the upper portion 1490 of the upper cylinder 1420 to control the start of blood flow into the strips 1451, 1452, 1453 and 1454 (not shown). In embodiments, a portion of the actuator 1406 lies outside of the upper cylinder 1420.
[0368] The strip 1451 is a negative control strip with reaction zone 1471 similar to the strip 911 with reaction zone 961 of FIG. 12A. Optical separation is important for an accurate reading of luminescence. To facilitate that, the test module 1400 includes optically opaque separators 1441 and 1442 with two not shown 1443 and 1444. The allows the module 1400 to be inserted into a photodiode-based optical reader such as that shown in FIG. 16 where at least one photodiode is aligned with each reaction zone e.g. 1471, 1472 etc., to have each photodiode accurately measure the luminescence from each zone and with electronic circuitry, that may include a microcomputer, analyze the results using an activity measurement calculation such as those described in association with FIGS. 11A, 11B and 11C.
[0369] The module 1400 can be used in several ways. In some embodiments it may be a stand-alone fully disposable device with an integrated reader with blood inserted from a syringe, vacuum collection tube, or other devices used to collect blood from venipuncture or a finger prick, or be set to be attached as a microtainer to a blood collection device such as the TASSO of Tasso, Inc.
[0370] In a preferred embodiment, the module 1400 can be designed to be inserted into a photodiode-based reader where only the module 1400 need be disposable.
[0371] Although four reaction zones 1471-1474 are described here, as few as one and as many as twenty zones or more may be used with a preferred embodiment of three or four zones.
[0372] The flow extension zones 1475, 1476, and not shown 1477 and 1478 perform the same function as the flow extension zones 925 of FIG. 12A.
[0373] It is also envisioned that each of the strips 1451, 1452, 1453 and 1454 excpet for the fluid input zones 1481, 1482, 1483 and 1484 could be coated with a sealing material, e.g., plastic or paraffin. This will cause the plasma to flow down each strip 1471-1474 and stop once the filter paper is fully saturated. A small air vent may also be added to the bottom of the sealed strips 1451, 1452, 1453 and 1454. Similar coatings are also applicable to the embodiments shown in FIGS. 13A, 13B, 13C, 15 and 16.
[0374] FIG. 15 is a schematic view of an embodiment of a two-piece TASSO/TET assay system 1500 with a Photonic Luminescence Reader (PLR) 1550 and the TASSO blood collection device 1510 with initiation button 1512 and with the normal collection vial replaced by an embodiment of the TET coupled enzyme assay test module 1520 similar to the test module 1400 of FIG. 14 but with the addition of the alignment key 1525. The test module 1520 is designed to receive the blood collected by the TASSO device 1500, separate the cells from the plasma allowing the plasma to flow along the four strips 1521, 1522, 1523 and 1524 (not shown) into the reaction zones 1531, 1532 and 1533 and 1534 (both not shown), picking up where needed chemicals in for example the substrate band 1542 of the test strip 1522.
[0375] The Photonic Luminescence Reader (PLR) 1550 with upper case 1552 includes an alignment female key slot 1582 as part of the generally cylindrical guide 1580. The guide 1580 has four attached photodiodes 1591, 1592, 1593 and not shown 1594 with cables 1595, 1596, 1597 and not shown 1598 to attach the photodiodes to electronic circuitry in the electronics module 1570. Each of the cables 1591-1594 has typically one or two wires each. The photodiodes 1591-1594 are attached to the cylindrical guide 1580 with at least the portion of the guide 1580 where the photodiodes 1591-1594 are attached being optically transparent. This can be accomplished by different embodiments including having a hole in the guide 1580, having the entire guide 1580 be transparent or in a preferred embodiment, having a transparent window under a portion of the photodiodes 1591, 1592, 1593 and not shown 1594. Embodiments with holes or windows may be preferred to prevent light leakage from one zone being detected by a photodiode aligned with another zone (i.e. crosstalk).
[0376] The PLR 1550 has an electronics module 1570 attached to the bottom of the upper case 1580 into which the cables 1595-1598 bring the signals from the photodiodes 1591-1594 to the electronic circuitry with an embodiment shown in FIG. 17. The outside of the PLR also includes a start button or switch 1572, a digital readout 1576 and an indicator LED 1574. The digital readout 1576 provides information on the quantitative measurement of the assay performed by the PLR 1550 with the LED 1574 being able to indicate one or more detection related conditions. For example, the LED 1574 might be red/green/yellow LED where it would be green if detection of NSE-FA is below the threshold for brain injury and red if above. It might flash while the device is working and could go yellow for an error condition. As noted above, other indicators including auditory could be present in different embodiments. In an embodiment of the present invention module 1520, strip 1521 is the negative control strip, strip 1522 is the test strip and strip 1523 is the positive control strip. In an embodiment, the 4th strip 1524 that is hidden behind the schematic view, can be one of the following: [0377] An additional test strip [0378] An additional positive or negative control strip [0379] An additional biomarker assay test different from that of the test strip 1522, for example for the NSE-FA assay a test that includes an inhibitor for Neuron Specific Enolase and allow luminescence from other types of enolase in the sample. Another example for liver enzymes is to have strip 1522 be for ALT and strip 1524 for AST with a common negative control (or positive control) for comparison.
[0380] It is envisioned that multiple digital displays or LEDs might also be used with configurations that could include indication of power on, negative result, positive result, error condition, test working and/or numerical or alphanumerical displays. Embodiments of the electronics module 1570 having wireless or wired telemetry as shown in FIG. 17 is also envisioned.
[0381] One embodiment of the method for using the system 1500 for detecting and measuring acute brain injury is as follows: [0382] 1. The TASSO device 1510 is removed from its package [0383] 2. The TET module 1520 is attached to the TASSO device 1510 in place of the normal container; [0384] 3. The TASSO is placed on the patient's arm, the central button 1512 is pressed to initiate blood collection; [0385] 4. After a pre-set time (e.g. 2-5 minutes) or when the blood fills the TET module 1520 to a marked level, the entire TASSO 1510 or just the module 1520 is removed from the patient and inserted into the PLR 1550 aligning the key 1525 of the module 1520 with the slot 1582 of the PLR 1550. [0386] 5. The start button 1572 is pressed and the electronic circuitry of the electronics module 1570 will collect luminescence data from the 4 photodiodes 1591-1594 for a pre-set period. [0387] 6. The electronics module 1570 will then calculate the enzymatic activity of the biomarker being assayed and show the result on the numerical display 1576. For example embodiments of example calculations are described along with FIGS. 11A, 11B and 11C. [0388] 7. The electronics module 1570 would also compare the value of the activity with a pre-set threshold and turn the LED 1574 red if above the threshold and green if below. [0389] 8. The TASSO 1510 with module 1520 are then disposed of. The PLR 1550 will turn off after the module 1480 is removed to be available for another reading.
[0390] It is also envisioned that a contact switch (not shown) could be added to the top of the electronics module 1570 activated when the module 1520 is inserted into the electronics module 1570 to automatically turn the electronics on, eliminating the need for the switch 1572. The contact switch may be located at different places with a preferred embodiment requiring that it activate once the reaction zones e.g. 1531 and 1532 align with the photodiodes 1591 and 1592 respectively.
[0391] FIG. 16 is a schematic view of an integrated and fully disposable point-of-care TET coupled enzyme assay system 1600 including a TASSO blood collection device 1510 with initiation button 1512. The standard TASSO blood collection vial is replaced by the TET coupled enzyme assay test module 1680 similar to the TET module 1520 of FIG. 15 or the TET module 1400 of FIG. 14. The TET module 1680 includes the test 1672, positive control 1673 and negative control 1671 blood filtration strips similar to the strips 1522, 1523 and 1521 respectively of the module 1520 of FIG. 15 but the module 1680 also includes the cylindrical housing 1690 with photodiodes 1691, 1692 and 1693 similar to the cylinder 1580 and photodiodes 1591, 1592 and 1593 of the separate PLR 1550 of FIG. 15. The photodiodes 1691, 1692, 1693 and 1694 (not shown) with cables 1695, 1696, 1697 and 1698 (not shown) perform the same function as the photodiodes 1591-1594 and cables 1595-1598 of FIG. 15.
[0392] The integrated assay 1600 has an electronics module 1670 attached to the bottom of the upper detection module 1690 into which the wires 1695-1698 bring the signals from the photodiodes 1691-1694 to the electronic circuitry. An embodiment of such electronic circuitry is shown in FIG. 17.
[0393] Operation of the system 1600 can be similar to that of the system 1500 of FIG. 15 with the TASSO 1510 button 1512 initiating both the collection of blood and the activation of the electronics module 1670 to measure the luminescence from the reaction zones (hidden) in the TET module 1690. The result is a qualitative and quantitative measurements of the assay shown by the color on the LED 1674 and numerically on the display 1676 respectively.
[0394] The two-piece embodiment is preferred if multiple tests need to be performed where the TASSO/TET 1510/1480 modules are disposable and the PLR 1550 is multi use. For single assay use such as for concussion at a football game, the fully disposable integrated PoC unit 1600 would be the preferred embodiment.
[0395] FIG. 17 is a block diagram of an embodiment of the electronics module 1700 that has features that would be incorporated into either or both electronic module embodiments 1570 of FIG. 15 and 1670 of FIG. 16. The module 1700 has a battery 1770, up to N photodiodes PD1 1701, PD2 1702, PD3 1703 through PDN 1704 whose signal is amplified and/or filtered through the amplifiers 1711, 1712, 1713 through 1714 whose output is digitized by the analog-to-digital converter(s) 1720. The digital signal is sampled into FIFO buffer memory 1730 and input to the central processing unit (CPU) 1740 with the A-to-D converter(s) 1720, FIFO Memory 1730 and CPU 1740 synchronized by the clock/timing sub system 1750.
[0396] In some embodiments, the CPU 1740 has one or more buttons/switches 1747 such as the start button 1572 of FIG. 15 or may receive input from depression of the TASSO button 1512 of FIGS. 15 and 16. The CPU 1740 also has assay data memory 1741, program memory 1742, and connects to a telemetry sub-system 1760 with Antenna 1765.
[0397] The telemetry subsystem 1760 with antenna 1765 may be configured to operate using a standard wireless protocol, for example: Bluetooth, WiFi or Medical Band (MICS). An embodiment of the telemetry sub-system 1760 may also provide a wired connector 1762 (e.g. USB, USB-C, lightning or other) to connect the system 1700 to a local computer, tablet or smart-phone (e.g. iPhone or Android).
[0398] In embodiments with a separate assay module/card and electronic module such as the configuration shown in FIG. 15, the electronics module may include a bar code reader 1749 to record the serial number of the assay module/card used in the assay that can be transmitted to external equipment using the telemetry sub-system 1760.
[0399] Also connected to the CPU is a temperature sensor 1748 whose reading may be used by the CPU 1740 to adjust parameters in the biomarker detection calculation for a TET assay that may be affected by temperature.
[0400] The output of the detection and measurement calculation(s) in the CPU 1740 can be displayed with the alpha-numeric display 1745 or the LED(s) 1746, or an auditory signal (not shown).
[0401] FIG. 18 is a schematic view showing a preferred embodiment of a point of care blood collection device 1500 such as the TASSO? with body 1510 and blood collection activator 1512. A blood collection vial/microtainer 1820 shown with collected blood 1830 and bottom surface 1825 suitable for needle penetration.
[0402] In embodiments, the microtainer 1820 has specific materials inside that can be used to pre-treat the blood (for example, the uricase and uric acid shown as A0 101 in FIG. 1. In embodiments, such materials may be freeze died and attached to the inner surface of the microtainer 1820 or simply placed into the microtainer 1820 as a powder or tablet.
[0403] FIG. 19 is a schematic view showing a preferred embodiment of a disposable NSE coupled enzyme reaction functional activity stroke test (NSE-FAST) assay 1900. The use of the assay 1900 is similar to that of the Lucira? Covid test sold by Pfizer. The embodiment of the assay 1900 has a case 1920, a numerical display 1905 and four LEDs including a ready LED 1902, a done LED 1904, a positive test LED 1906 and a negative test LED 1908. The assay 1900 has a cylindrical slot 1920 for insertion of the microtainer 1820 with bottom surface 1825 of FIG. 18. At the bottom of the slot 1920 (not shown) is a needle to puncture the bottom surface 1825 of the microtainer 1820 to allow blood 1830 to flow into the assay 1900 where blood separation paper strips similar to the blood separation paper strip set 900 shown in FIG. 12A with negative control strip 911, test strip 912 and positive control strip 913 would be used to separate out plasma that would then flow the into reaction zones similar to those shown in FIG. 12A, 13A, or 14A. Photo diodes (not shown) similar to the photo diodes 1701 through 1703 of FIG. 17 would sense the luminescence for test, positive control and negative control reaction zone(s) and the CPU 1740 of FIG. 17 would then calculate the activity of the enzyme in the patient sample as previously described. The CPU 1740 would then display the result using the numerical value 1905 and/or the test result positive LED 1906 or test result negative LED 1908. It is also envisioned that the assay 1900 may also utilize embodiments shown in FIG. 13A, 13B or 13C.
[0404] In embodiments, in addition or instead of the display it is envisioned that the CPU 1740 of FIG. 17 would transmit the result (measurement and/or positive/negative) to external equipment (not shown) through the telemetry sub-system 1760 over the wired connector 1762 or antenna 1765 of FIG. 17.
[0405] Similar to the Lucira? Covid test, although not shown, the bottom of the case 1920 could have a battery cover 1910 into which one or more batteries (e.g. the battery 1770 of FIG. 17) can be inserted to start the electronics running in preparation for the test. Alternately, the battery could be embedded and the insertion of the microtainer 1820 could turn the system on.
[0406] An embodiment of the present invention assay 1900 shown in FIG. 19 is envisioned for tethered enzyme PoC applications for many different biomarkers including the NSE-FA assay and ALT & AST liver enzyme assays shown in FIG. 2.
[0407] Also, while the example for FIG. 19 shows use with whole blood from a TASSO device, it is envisioned that the microtainer 1820 can be filled with plasma, serum, urine or liquid into which material from a nasal swab or other material is dissolved to facilitate detection of different biomarkers.
[0408] It is envisioned that for assays of liver enzymes ALT and AST the embodiment of the assay 1900 would have separate displays and positive and negative LEDs for each with a preferred embodiment using five blood separation chromatography strips like the strips 1200 of FIG. 12E if the pre-treatment bands 1220 are on the strip or like the strips 900 of FIG. 12A if the pre-treatment materials are in the microtainer 1820.
[0409] Throughout this specification we describe use of freezing and freeze-drying as important to the present invention as these will prevent premature activation of chemical reactions. It is envisioned that other methods can be used to also prevent premature activation of the chemical reactions described herein and embodiments using these other methods may also facilitate production of the present invention assays. Examples include manipulations of the combination of pressure and temperature, using powdered components including enzymes and the use of reaction inhibitors or dissolvable physical barriers between layers. Another technique envisioned is using encapsulated or caged components to prevent premature mixing of components. A final version is to utilize magnetic particles that can remain separated until the field is removed.
[0410] While the well versions of the present invention coupled enzyme assays are intended for use with plate readers capable of measuring luminescence, it is envisioned that small dedicated devices could be implemented to measure the luminescence from the wells using photo-diodes, CCD arrays, photomultiplier tubes or any other photon detection or measurement device.
[0411] While the present invention embodiments of the point-of-care assays show the use of photodiodes, embodiments using other photon detection or measurement devices including CCD arrays and photomultiplier tubes are envisioned.
[0412] While the present invention specification describes assays for Neuron Specific Enolase, these embodiments are equally appropriate and are applicable to an assay for any active enolase enzyme.
[0413] Various other modifications, adaptations, and alternative designs are of course possible in light of the above teachings. Therefore, it should be understood at this time that, within the scope of the appended claims, the invention can be practiced otherwise than as specifically described herein.
