Detection of analytes in a dual-mediator electrochemical test strip

• US 8,057,659 B2
• Filed: 06/26/2007
• Issued: 11/15/2011
• 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
• Primary Examiner(s): Barton; Jeffrey T
• Assistant Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US11/768,341
• Publication Number:
  US 20070295616A1
• Time in Patent Office: 1,603 Days
• Field of Search: 205/777.5, 205/779, 205/775, 205/778, 205/792, 20440301-40315, 204/400, 435/4, 435/14, 435/25
• US Class Current: 205/792
• 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 method for detecting glucose in a sample comprising the steps of:

(a) applying a sample to be evaluated for the presence of glucose to a test strip, wherein the test strip comprises;

a support portion defining a sample chamber;

a working and a counter electrode disposed within the sample chamber; and

a reagent composition disposed in the sample chamber, said reagent composition comprising (i) an active redox enzyme effective to oxidize glucose in the sample, (ii) a mediator compound, and (iii) a shuttle compound, wherein the shuttle compound and the mediator compound are different from one another;

wherein

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

the mediator is [Os(Mebpy)₂Pic]^+/2+ and

the shuttle is ferri/ferrocyanide, and

(b) applying a potential between the working and the counter electrodes to generate current that is indicative of the amount of glucose in the sample.

2. 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 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 the analyte and produces an inactive enzyme that is reduced,

the mediator is [Os(Mebpy)₂Pic]^+/2+ and

the shuttle is ferri/ferrocyanide.

3. The method of claim 2, 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 method of claim 2, wherein the reagent composition further comprises a third electron transfer agent that transfers electrons between the mediator and the shuttle.

5. The method of claim 2, wherein the analyte is glucose and the enzyme is glucose oxidase.

6. 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 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 the analyte and produces an inactive enzyme that is reduced,

the mediator is [Os(Mebpy)₂Pic]^+/2+ and

the shuttle is ferri/ferrocyanide.

7. The sensor of claim 6, wherein the shuttle compound is present in at least a ten-fold excess with respect to the mediator compound on a molar basis.

8. The sensor of claim 6, wherein the reagent composition further comprises a third electron transfer agent that transfers electrons between the mediator and the shuttle.

9. The sensor of claim 6, wherein the analyte is glucose and the enzyme is glucose oxidase.