Opposable-element assay device employing unidirectional flow

• US 5,879,951 A
• Filed: 01/29/1997
• Issued: 03/09/1999
• Est. Priority Date: 01/29/1997
• Status: Expired due to Fees

• Current Assignee: Beckman Coulter Incorporated (Danaher Corporation)
• Original Assignee: Smithkline Diagnostics, Inc. (GlaxoSmithKline PLC)
• Inventors: Sy, Vincent A.
• Primary Examiner(s): Chin, Christopher L.
• Application Number:
  US08/791,769
• Time in Patent Office: 769 Days
• Field of Search: 422/56-58, 422/61, 435/7.9, 435/7.92, 435/287.1, 435/287.2, 435/287.7, 435/287.8, 435/287.9, 435/805, 435/810, 435/970, 435/975, 436/514, 436/518, 436/528, 436/530, 436/169, 436/805, 436/808, 436/810
• US Class Current: 436/514
• CPC Class Codes: G01N 33/54386 Analytical elements
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/81 Packaged device or kit
• CPC Class Codes: Y10S 435/97 Test strip or test slide
• CPC Class Codes: Y10S 435/975 Kit
• CPC Class Codes: Y10S 436/805 Optical property
• CPC Class Codes: Y10S 436/808 Automated or kit
• CPC Class Codes: Y10S 436/81 Tube, bottle, or dipstick

Abstract

An assay device for the performance of assays for analytes, particularly those of biological interest, provides for improved efficiency and sensitivity by reducing background. The assay device performs an immunochromatographic assay and also provides a wash to remove unbound labeled specific binding partner and thereby reduce the background. Assay devices according to the present invention can use either a directly visible label such as a metal sol label or an enzyme label. One embodiment of assay devices according to the present invention is particularly suitable for assay of analytes in whole blood samples. The present invention also encompasses test kits and methods of use of the assay devices.

Claims

1. A chromatographic assay device for detection and/or determination of an analyte comprising:

(a) a first opposable component including;

(i) a sample preparation zone for receiving a sample to be assayed; and

(ii) a chromatographic medium having first and second ends and having a detection zone containing an immobilized specific binding partner for the analyte, the chromatographic medium being separated from the sample preparation zone on the first opposable component; and

(b) a second opposable component including;

(i) a conductor;

(ii) an absorber separated from the conductor; and

(iii) an applicator separated on the second opposable component from the conductor and the absorber;

wherein the first and second opposable components are configured so that bringing the first and second opposable components into operable contact results in the absorber coming into operable contact with the second end of the chromatographic medium, the conductor coming into operable contact with the sample preparation zone and the first end of the chromatographic medium, and in the applicator coming into operable contact with the sample preparation zone so that the sample preparation zone bridges the applicator and the conductor, and so that the chromatographic medium bridges the conductor and the absorber.

2. The chromatographic assay device of claim 1 wherein the sample preparation zone, the conductor, or both include a labeled specific binding partner for the analyte in resolubilizable form.

3. The chromatographic assay device of claim 1 wherein the sample preparation zone contains at least one reagent for treatment of the sample before the sample is applied to the chromatographic medium.

4. The chromatographic assay device of claim 3 wherein the reagent for treatment of the sample is a extraction reagent to extract analyte from the sample.

5. The chromatographic assay device of claim 2 wherein the label of the labeled specific binding partner is a visible label.

6. The chromatographic assay device of claim 1 wherein the chromatographic medium further includes a control zone separate from the detection zone.

7. The chromatographic assay device of claim 6 wherein the control zone contains analyte immobilized thereto.

8. The chromatographic assay device of claim 1 wherein at least one of the first and second opposable components includes an aperture therein for viewing of at least a portion of the chromatographic medium.

9. A test kit comprising, packaged in separate containers:

(a) the assay device of claim 1; and

(b) a wash liquid for application to the applicator of the assay device.

10. A method for detecting and/or determining an analyte in a sample comprising the steps of:

(a) applying the sample to the sample preparation zone of the chromatographic assay device of claim 1;

(b) applying a wash liquid to the applicator of the chromatographic assay device;

(c) bringing the first and second opposable components of the assay device into opposition;

(d) allowing the sample and the resolubilized labeled specific binding partner to move through at least a portion of the chromatographic medium including the detection zone, followed by the wash liquid from the applicator, so that the detection reagent give a detectable indication of the presence and/or quantity of the analyte; and

(e) observing and/or measuring the labeled specific binding partner at the detection zone in order to detect and/or determine the analyte.

11. The method of claim 10 wherein the detectable label is a visually detectable label and the step of observing and/or measuring the labeled specific binding partner bound at the detection zone comprises visually observing the labeled specific binding partner.

21. A method for detecting and/or determining an analyte in a sample comprising the steps of:

(a) applying the sample to the labeled specific binding partner applicator located farthest from the chromatographic medium of the chromatographic assay device of claim 11;

(b) applying a wash liquid to the wash liquid applicator of the chromatographic assay device;

(c) bringing the first and second opposable components of the chromatographic assay device into operable contact;

(d) allowing the sample and the resolubilized labeled specific binding partner, followed by the wash liquid, to move through at least a portion of the chromatographic medium including the detection zone so the labeled specific binding partner gives a detectable indication of the present and/or quantity of the analyte; and

(e) observing and/or measuring the labeled specific binding partner at the detection zone in order to detect and/or determine the analyte.

22. The method of claim 21 wherein the label of the labeled specific binding partner is a visually detectable label and the step of observing and/or measuring the labeled specific binding partner comprises visually observing the labeled specific binding partner.

12. A chromatographic assay device for detection and/or determination of an analyte comprising:

(a) a first opposable component including;

(i) a plurality of labeled specific binding partner applicators, each labeled specific binding partner applicator for applying a labeled specific binding partner for the analyte to the chromatographic medium; and

(ii) a chromatographic medium having first and second ends and including a detection zone containing an immobilized specific binding partner for the analyte, the chromatographic medium being separated from the labeled specific binding partner applicators on the first opposable component, at least one of the labeled specific binding partner applicators for receiving a sample to be assayed; and

(b) a second opposable component including;

(i) at least one conductor, with there being at least as many conductors as the number of labeled specific binding partner applicators on the first opposable component minus one, the conductors being located on the second opposable component such that, when the first and second opposable component are brought into operable contact, one conductor is in operable contact with a labeled specific binding partner applicator and the chromatographic medium and the other conductors are in operable contact with two labeled specific binding partner applicators;

(ii) an absorber separated from the conductors on the second opposable components; and

(iii) a wash liquid applicator separated on the second opposable component from the conductors and absorber;

wherein bringing the first and second opposable components into operable contact causes the absorber to come into operable contact with the second end of the chromatographic medium, causes the conductors to come into operable contact with the sample preparation zones, and causes the wash liquid applicator to come into operable contact with the labeled specific binding partner applicator that is located the farthest from the chromatographic medium.

13. The chromatographic assay device of claim 12 wherein at least one of the labeled specific binding partner applicators contains a labeled specific binding partner for the analyte in resolubilizable form.

14. The chromatographic assay device of claim 12 wherein the labeled specific binding partner applicator for receiving the sample contains a reagent for treatment of the sample before the sample is applied to the chromatographic medium.

15. The chromatographic assay device of claim 14 wherein the reagent is an extraction reagent for extracting analyte from the sample.

16. The chromatographic assay device of claim 13 wherein the labeled specific binding partner for the analyte is a visually detectable label.

17. The chromatographic assay device of claim 12 wherein the chromatographic medium further includes a control zone separate from the detection zone.

18. The chromatographic assay device of claim 17 wherein the control zone contains analyte immobilized thereto.

19. The chromatographic assay device of claim 12 wherein at least one of the first and second opposable components further includes an aperture for viewing of at least a portion of the chromatographic medium.

20. A test kit comprising, packaged in separate containers:

(a) the assay device of claim 12; and

(b) a wash liquid for application to the wash liquid applicator of the assay device.

23. A chromatographic assay device for detection and/or determination of an analyte comprising;

(a) a first opposable component including

(i) a chromatographic medium having first and second ends and including a detection zone containing an immobilized specific binding partner for the analyte;

(ii) a sample preparation zone for receiving a sample to be assayed, the sample preparation zone including a catalyst-labeled specific binding partner for the analyte in resolubilizable form, the sample preparation zone being separated from the chromatographic medium; and

(iii) a first applicator containing a substance that participates in a reaction catalyzed by the catalyst to produce a detectable product, the first applicator being separated on the first opposable component from the chromatographic medium and the sample preparation zone; and

(b) a second opposable component including;

(i) a second applicator;

(ii) a conductor; and

(iii) an absorber separated from the conductor and the second applicator;

wherein the first and second opposable components are configured such that bringing the first and second opposable components into operable contact causes the second applicator to come into operable contact with both the first applicator and the sample preparation zone, causes the conductor to come into operable contact with both the sample preparation zone and the first end of the chromatographic medium, and causes the absorber to come into operable contact with the second end of the chromatographic medium.

24. The chromatographic assay device of claim 23 wherein the sample preparation zone contains at least one reagent for treatment of the sample before the sample is applied to the chromatographic medium.

25. The chromatographic assay device of claim 24 wherein the reagent is an extraction reagent for extracting analyte from the sample.

26. The chromatographic assay device of claim 23 wherein the catalyst is an enzyme.

27. The chromatographic assay device of claim 26 wherein the enzyme is selected from the group consisting of horseradish peroxidase, alkaline phosphatase, β

-galactosidase, and glucose oxidase.

28. The chromatographic assay device of claim 23 wherein the substance that participates in a reaction is a substrate that is converted to an insoluble product that is deposited at the detection zone as the result of the action of the catalyst.

29. The chromatographic assay device of claim 23 wherein the chromatographic medium further includes a control zone separate from the detection zone.

30. The chromatographic assay device of claim 28 wherein the control zone includes analyte immobilized thereto.

31. The chromatographic assay device of claim 23 wherein at least one of the first and second opposable components further includes an aperture for viewing of at least a portion of the chromatographic medium.

32. A test kit, comprising, packaged in separate containers:

(a) the assay device of claim 23; and

(b) a wash liquid for application to the second applicator of the assay device.

33. A method for detecting and/or determining an analyte in a sample comprising the steps of:

(a) applying the sample to the sample preparation means of the chromatographic assay device of claim 23;

(b) applying a wash liquid to the second applicator of the chromatographic assay device;

(c) bringing the first and second opposable component into operable contact;

(d) allowing the sample and the reactant, followed by the wash liquid, to move through at least a portion of the chromatographic medium including the detection zone so that the labeled specific binding partner gives a detectable indication of the presence and/or quantity of the analyte; and

(e) observing and/or measuring the labeled specific binding partner at the detection zone in order to detect and/or determine the analyte.

34. A chromatographic assay device for detection and/or determination of an analyte in a sample comprising;

(a) a first opposable component including;

(i) a sample preparation zone containing a matrix of porous material permeable to the liquid portion of blood but capable of trapping the cellular components of blood;

(ii) a first applicator containing a labeled specific binding partner for the analyte in resolubilizable form in operable contact with the sample preparation zone; and

(iii) a chromatographic medium including a detection zone containing an immobilized specific binding partner for the analyte, the chromatographic medium being in operable contact with the first applicator, the chromatographic medium, first applicator, and sample preparation zone being so located that the first applicator is between the sample preparation zone and the chromatographic medium; and

(b) a second opposable component including;

(i) a second applicator; and

(ii) an absorber;

wherein the first and second opposable components are configured so that bringing the first and second opposable components into operable contact causes the second applicator to come into operable contact with the first applicator to apply a wash liquid thereto and causes the absorber to come into operable contact with the second end of the chromatographic medium.

35. The chromatographic assay device of claim 34 further comprising a barrier to prevent fluid flow between the second applicator and the sample preparation zone.

36. The chromatographic assay device of claim 34 wherein the chromatographic medium further includes a control zone separate from the detection zone.

37. The chromatographic assay device of claim 36 wherein the control zone includes analyte immobilized thereto.

38. A test kit comprising, packaged in separate containers:

(a) the assay device of claim 34; and

(b) a wash liquid for application to the second applicator of the assay device.

39. A method for detecting and/or determining an analyte in a test sample comprising the steps of:

(a) applying the test sample to the sample preparation zone of the chromatographic assay device of claim 34;

(b) applying a wash liquid to the second applicator of the chromatographic assay device;

(c) allowing the sample to migrate from the sample preparation zone through the first applicator to resolubilize the labeled specific binding partner and then through at least a portion of the chromatographic medium, the portion including the detection zone;

(d) bringing the first and second opposable components into operable contact to apply the wash liquid to the sample preparation zone and the first applicator;

(e) allowing the wash liquid to move through at least a portion of the chromatographic medium including the detection zone; and

(f) observing and/or measuring the labeled specific binding partner at the detection zone in order to detect and/or determine the analyte.

40. The method of claim 39 wherein the label of the labeled specific binding partner is a visually detectable label and the step of observing and/or measuring the labeled specific binding partner comprises visually observing the labeled specific binding partner.

51. The chromatographic assay device of claim 34 wherein the matrix contains a detergent and a chelating agent.

41. A chromatographic assay device for detection and/or determination of at least one analyte comprising:

(a) a first opposable component including;

(i) a plurality of laterally separated sample preparation zones, each sample preparation zone for receiving a sample to be assayed; and

(ii) a plurality of laterally separated chromatographic media, each chromatographic medium having first and second ends and including therein a detection zone containing an immobilized specific binding partner for an analyte, each chromatographic medium being located in a line with a sample preparation zone; and

(b) a second opposable component including;

(i) a plurality of laterally separated conductors;

(ii) a plurality of laterally separated absorbers, each absorber being located in line with a conductor; and

(iii) a plurality of laterally separated applicators, each applicator being located in line with an absorber and a conductor;

wherein, when the first and second opposable components are brought into operable contact, each applicator is brought into operable contact with a corresponding sample preparation zone, each conductor is brought into operable contact with a corresponding sample preparation zone and with a corresponding chromatographic medium, and each absorber is brought into operable contact with the second end of a corresponding chromatographic medium.

42. The chromatographic assay device of claim 41 wherein at least one sample preparation zone includes a specific binding partner for an analyte in resolubilizable form.

43. The chromatographic assay device of claim 41 wherein at least one sample preparation zone includes a reagent for treatment of the sample before application of the sample to the chromatographic medium.

44. A chromatographic assay device for detection and/or determination of at least one analyte comprising:

(a) a first opposable component including;

(i) a plurality of laterally separated chromatographic media, each chromatographic medium having first and second ends and including thereon a detection zone containing an immobilized specific binding partner for an analyte;

(ii) for each chromatographic medium, a plurality of labeled specific binding partner applicators for applying a labeled specific binding partner for an analyte to the chromatographic medium, the labeled specific binding partner applicator located furthest from the chromatographic medium for receiving a sample to be assayed, each chromatographic medium being located on the first opposable component in line with an equal number of labeled specific binding partner applicators; and

(b) a second opposable component including;

(i) a plurality of laterally-separated wash liquid applicators, one applicator for each chromatographic medium;

(ii) a plurality of laterally-separated conductors, each conductor being located in line with a wash liquid applicator, with there being at least as many conductors for each chromatographic medium as the number of labeled specific binding partner applicators minus one for each chromatographic medium; and

(iii) a plurality of laterally-separated absorbers, one absorber for each chromatographic medium, each absorber being located in line with a wash liquid applicator and a conductor;

wherein, when the first and second opposable components are brought into opposition, each wash liquid applicator is brought into operable contact with a corresponding labeled specific binding partner applicator, the corresponding labeled specific binding partner applicators being those that are located the farthest from each chromatographic medium, each conductor is brought into operable contact with either two corresponding labeled specific binding partner applicators or a corresponding labeled specific binding partner applicator and the first end of a corresponding chromatographic medium, and each absorber is brought into operable contact with the second end of a corresponding chromatographic medium.

45. The chromatographic assay device of claim 44 wherein at least one labeled specific binding partner applicator includes a labeled specific binding partner for an analyte in resolubilizable form.

46. The chromatographic assay device of claim 44 wherein at least one labeled specific binding partner applicator includes a reagent for treatment of the analyte.

47. A chromatographic assay device for detection and/or determination of at least one analyte comprising:

(a) a first opposable component including;

(i) a plurality of laterally-separated chromatographic media, each chromatographic medium having first and second ends and including thereon a detection zone containing an immobilized specific binding partner for an analyte;

(ii) a plurality of laterally-separated sample preparation zones, one for each chromatographic medium, each sample preparation zone including a specific binding partner for an analyte in a resolubilizable form labeled with a catalyst, each sample preparation zone being in line with a chromatographic medium; and

(iii) a plurality of first applicators, one for each chromatographic medium, each first applicator containing a substrate that participates in a reaction catalyzed by the catalyst, the reaction forming a detectable product, each first applicator being in line with a chromatographic medium and a sample preparation zone; and

(b) a second opposable component including;

(i) a plurality of laterally-separated second applicators, one second applicator for each chromatographic medium;

(ii) a plurality of laterally-separated conductors, one conductor for each chromatographic medium, each conductor being in line with a second applicator; and

(iii) a plurality of laterally-separated absorbers, one absorber for each chromatographic medium, each absorber being in line with a second applicator and a conductor;

wherein the first and second opposable components are configured so that bringing the first and second opposable components into operable contact causes each second applicator to come into operable contact with a corresponding first applicator and sample preparation zone, causes each conductor to come into operable contact with a corresponding sample preparation zone and chromatographic medium via the first end of the chromatographic medium, and causes each absorber to come into operable contact with a corresponding chromatographic medium via the second end of each chromatographic medium.

48. The chromatographic assay device of claim 47 wherein the catalyst is an enzyme.

49. A chromatographic assay device for detection and/or determination of at least one analyte comprising:

(a) a first opposable component including;

(i) a plurality of laterally-separated chromatographic media, each chromatographic medium having first and second ends and including thereon a detection zone containing an immobilized specific binding partner for an analyte;

(ii) a plurality of laterally-separated first applicators, one first applicator for each chromatographic medium, each first applicator being in operable contact with the first end of a corresponding chromatographic medium; and

(iii) a plurality of laterally-separated sample preparation zones, each sample preparation zone being in operable contact with a corresponding first applicator, each sample preparation zone including therein a matrix of porous material permeable to the liquid portion of blood but capable of trapping the cellular components of blood; and

(b) a second opposable component including;

(i) a plurality of laterally-separated second applicators, one for each chromatographic medium; and

(ii) a plurality of laterally-separated absorbers, one for each chromatographic medium, each absorber being in line with a second applicator;

wherein the first and second opposable components are configured so that bringing the first and second opposable components into operable contact causes each second applicator to come into operable contact with the corresponding first applicator and causes each absorber to come into operable contact with the corresponding chromatographic medium via the second end of the chromatographic medium.

50. The chromatographic assay device of claim 49 wherein each matrix of porous material contains a detergent and a chelating agent.