Detection of Analytes in a Dual-mediator Electrochemical Test Strip

• US 20070295616A1
• Filed: 06/26/2007
• Published: 12/27/2007
• Est. Priority Date: 06/27/2006
• Status: Active Grant

• Current Assignee: Agamatrix Incorporated (AgaMatrix Holdings LLC d/b/a WaveForm Diabetes)
• Original Assignee: Agamatrix Incorporated (AgaMatrix Holdings LLC d/b/a WaveForm Diabetes)
• Inventors: Harding, Ian, Iyengar, Sridhar
• Granted Patent: US 8,057,659 B2
• Time in Patent Office: Days
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

Determination of an analyte such as glucose in a sample is done making use of a plurality of electron transfer reagents, for example two electron transfer reagents, that work together to transfer electrons between the enzyme and the electrodes. The first electron transfer agent is a mediator that interacts with the enzyme after it has acted on the analyte to regenerate enzyme in its active form. The second electron transfer agent is a shuttle that interacts with the electrodes and optionally the mediator. The oxidation and reduction of the shuttle serves as the major source of current that is measured as an indication of analyte.

Claims

1. A sensor for the detection of an analyte in a sample, comprising:

(a) a support portion defining a sample chamber;

(b) a working and a counter electrode disposed within the sample chamber; and

(c) a reagent composition disposed in the sample chamber, said reagent composition comprising (i) an active redox enzyme effective to oxidize or reduce the analyte, (ii) a mediator compound, and (iii) a shuttle compound, wherein

when a sample containing analyte is introduced into the sample chamber, the redox enzyme oxidizes or reduces the analyte and produces an inactive enzyme that is reduced or oxidized,

the mediator is selected such that it will react with the inactive enzyme to regenerate the active redox enzyme, and

the shuttle is soluble in the sample to be applied, and has slow or no reaction with O₂.

2. The sensor of claim 1, wherein the mediator has an E⁰ of less than 150 mV.

3. The sensor of claim 1, wherein the shuttle compound is present in at least a ten-fold excess with respect to the mediator compound on a molar basis.

4. The sensor of claim 3, wherein the shuttle compound is ferri/ferrocyanide.

5. The sensor of claim 1, wherein the shuttle compound is ferri/ferrocyanide.

6. The sensor of claim 1, wherein the shuttle compound has an E⁰ less than the E⁰ of the mediator.

7. The sensor of claim 1, wherein the shuttle compound has an E⁰ greater than the E⁰ of the mediator.

8. The sensor of claim 1, wherein the shuttle compound has an E⁰ equal to that E⁰ of the mediator.

9. The sensor of claim 1, wherein the shuttle compound reacts directly with the mediator in solution in a redox reaction.

10. The sensor of claim 1, wherein the reagent composition further comprises a third electron transfer agent that transfers electrons between the mediator and the shuttle.

11. The sensor of claim 1, wherein the mediator is selected from the group consisting of:

metallocenes,

metal clusters, and

metal compounds having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

13. The sensor of claim 1, wherein the mediator is a Ru, Os, Fe or Co having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

14. The sensor of claim 13, wherein the shuttle compound is ferri/ferrocyanide.

15. The sensor of claim 1, wherein the mediator is [Os(MeBpy)₂(Im)₂]^2+/3+ or [Os(Mebpy)2Pic]^+/2+.

16. The sensor of claim 15, wherein the shuttle compound is ferri/ferrocyanide.

17. The sensor of claim 1, wherein the mediator is ferrocene/ferrocinium.

18. The sensor of claim 17, wherein the shuttle compound is ferri/ferrocyanide.

19. The sensor of claim 1, wherein the analyte is glucose and the enzyme is glucose oxidase.

20. The sensor of claim 19, wherein the mediator is selected from the group consisting of:

metallocenes,

metal clusters, and

metal compounds having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

21. The sensor of claim 20, wherein the shuttle compound is ferri/ferrocyanide.

22. The sensor of claim 19, wherein the mediator is a Ru, Os, Fe or Co having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

23. The sensor of claim 22, wherein the shuttle compound is ferri/ferrocyanide.

24. The sensor of claim 19, wherein the mediator is [Os(MeBpy)₂(Im)₂]^2+/3+ or [Os(Mebpy)2Pic]^+/2+.

25. The sensor of claim 24, wherein the shuttle compound is ferri/ferrocyanide.

26. The sensor of claim 19, wherein the mediator is ferrocene/ferrocinium.

27. The sensor of claim 26, wherein the shuttle compound is ferri/ferrocyanide.

46. The method of claim 26, wherein the analyte is glucose and the enzyme is glucose oxidase.

47. The method of claim 46, wherein the mediator is selected from the group consisting of:

metallocenes,

metal clusters, and

metal compounds having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

48. The method of claim 47, wherein the shuttle compound is ferri/ferrocyanide.

49. The method of claim 46, wherein the mediator is a Ru, Os, Fe or Co having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

50. The method of claim 49, wherein the shuttle compound is ferri/ferrocyanide.

51. The method of claim 46, wherein the mediator is [Os(MeBpy)₂(Im)₂]^2+/3+ or [Os(Mebpy)2Pic]^+/2+.

52. The method of claim 51, wherein the shuttle compound is ferri/ferrocyanide.

53. The method of claim 46, wherein the mediator is ferrocene/ferrocinium.

54. The method of claim 53, wherein the shuttle compound is ferri/ferrocyanide.

28. A method for detecting an analyte in a sample comprising the steps of:

introducing the sample into a sensor, wherein said sensor comprises;

(a) a support portion defining a sample chamber;

(b) a working and a counter electrode disposed within the sample chamber; and

(c) a reagent composition disposed in the sample chamber, said reagent composition comprising (i) an active redox enzyme effective to oxidize or reduce the analyte, (ii) a mediator compound, and (iii) a shuttle compound, wherein

when a sample containing analyte is introduced into the sample chamber, the redox enzyme oxidizes or reduces the analyte and produces an inactive enzyme that is reduced or oxidized,

the mediator is selected such that it will react with the inactive enzyme to regenerate the active redox enzyme, and

the shuttle is soluble in the sample to be applied, and has slow or no reaction with O₂,

applying a potential between the working and counter electrodes, and

observing the current between the electrodes as an indication of analyte in the sample.

29. The method of claim 28, wherein the mediator has an E⁰ of less than 150 mV.

30. The method of claim 28, wherein the shuttle compound is present in at least a ten-fold excess with respect to the mediator compound on a molar basis.

31. The method of claim 30, wherein the shuttle compound is ferri/ferrocyanide.

32. The method of claim 28, wherein the shuttle compound is ferri/ferrocyanide.

33. The method of claim 28, wherein the shuttle compound has an E⁰ less than the E⁰ of the mediator.

34. The method of claim 28, wherein the shuttle compound has an E⁰ greater than the E⁰ of the mediator.

35. The method of claim 28, wherein the shuttle compound has an E⁰ equal to that E⁰ of the mediator.

36. The method of claim 28, wherein the shuttle compound reacts directly with the mediator in solution in a redox reaction.

37. The method of claim 28, wherein the reagent composition further comprises a third electron transfer agent that transfers electrons between the mediator and the shuttle.

38. The method of claim 28, wherein the mediator is selected from the group consisting of:

metallocenes,

metal clusters, and

metal compounds having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

39. The method of claim 38, wherein the shuttle compound is ferri/ferrocyanide.

40. The method of claim 28, wherein the mediator is a Ru, Os, Fe or Co having ligands selected from the group consisting of bipyridyl, phenanthroline, imidazole, thiolene, thiolate, thioether, sulfide, porphyrins, pyrrole, pyrrazole, thiazole, diazole, triazole, picolinate, carboxylate, oxo and quinone.

41. The method of claim 40, wherein the shuttle compound is ferri/ferrocyanide.

42. The method of claim 28, wherein the mediator is [Os(MeBpy)₂(Im)₂]^2+/3+ or [Os(Mebpy)2Pic]^+/2+.

43. The method of claim 42, wherein the shuttle compound is ferri/ferrocyanide.

44. The method of claim 28, wherein the mediator is ferrocene/ferrocinium.

45. The method of claim 44, wherein the shuttle compound is ferri/ferrocyanide.