Reagent composition for electrochemical biosensors

• US 8,921,065 B2
• Filed: 03/03/2006
• Issued: 12/30/2014
• Est. Priority Date: 03/04/2005
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation), Syracuse University
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Chu, Amy H., Spradlin, Hope G.
• Primary Examiner(s): Hanley, Susan
• Assistant Examiner(s): MARTIN, PAUL C
• Application Number:
  US11/885,237
• Publication Number:
  US 20080199937A1
• Time in Patent Office: 3,224 Days
• Field of Search: 435/26, 435/200, 435/287.1
• US Class Current: 435/26
• 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

A reagent composition containing GDH-PQQ as an enzyme-co-factor and screen-printed on working and counter electrodes of electrochemical biosensors, maintains activity of the enzyme reagents by proper selection of components. A preferred composition includes hydrophilic polymers, amorphous untreated silica, buffers, surfactants, and a mediator. For example, the biosensor is useful in the amperometric determination of glucose.

Claims

1. A reagent composition for making electrochemical biosensors comprising:

(a) glucose dehydrogenase (GDH) and co-factor pyrrolo-quinoline quinone (PQQ) for oxidizing glucose in a biological sample;

(b) 2 to about 10 wt % of a hydrophilic polymer selected from cellulose derivatives, based on the total weight of the composition;

(c) about 1 to about 6 wt % of amorphous untreated silica powder, based on the total weight of the composition;

(d) a buffer sufficient to maintain pH in the range of from about 4.5 to about 6.5;

(e) a surfactant; and

(f) a mediator.

2. The reagent composition of claim 1, wherein said buffer is an acetate, citrate, or succinate buffer.

3. The reagent composition of claim 2, wherein said buffer is present in about 30 to about 200 mM.

4. The reagent composition of claim 3, wherein said buffer is present in about 50 to about 150 mM.

5. The reagent composition of claim 1, wherein said surfactant is an alkyl aryl polyether alcohol.

6. The reagent composition of claim 5, wherein up to about 0.5 wt % of said polyether alcohol is present, based on the total weight of the composition.

7. The reagent composition of claim 1, wherein said mediator is potassium ferricyanide.

8. The reagent composition of claim 7, wherein about 10 to about 20 wt % of said potassium ferricyanide is present, based on the total weight of the composition.

9. The reagent composition of claim 1, wherein the pH of the buffer ranges from 5.0 to 6.0.

10. The reagent composition of claim 9, wherein said composition has a viscosity of about 60,000 to about 180,000 cps (mPa·

s).

11. The reagent composition of claim 1, wherein said hydrophilic polymer is a cellulose derivative selected from the group consisting of sodium carboxymethyl cellulose, hydroxy ethyl cellulose, hydroxy propyl cellulose, and hydroxy propylmethyl cellulose.

12. The reagent composition of claim 11, wherein said hydrophilic polymer is hydroxyethyl cellulose.

13. The reagent composition of claim 1, wherein 1-8 units of said GDH-PQQ is present for each milligram of the total weight of the composition.

14. The reagent composition of claim 1, wherein said amorphous untreated silica powder is hydrophilic.

15. The reagent composition of claim 1, further comprising about 5 to about 50 mM of calcium chloride.

16. The reagent composition of claim 1, wherein the bias associated therewith is within ±

10%.

17. The reagent composition of claim 1, wherein the bias associated therewith is within ±

5% for samples having ≦

400 mg/dL glucose.

18. A reagent composition for making electrochemical biosensors comprising:

(a) glucose dehydrogenase (GDH) and co-factor pyrrolo-quinoline quinone (PQQ) for oxidizing glucose in a biological sample, wherein about 1-8 units of said GDH-PQQ is present for each milligram of the total weight of the composition;

(b) 2 to about 10 wt % of a hydrophilic polymer selected from cellulose derivatives, based on the total weight of the composition;

(c) about 1 to about 6 wt % of a thickening agent selected from the group consisting of amorphous untreated silica powder, talc, mica, diatomaceous earth, and natural and modified clays, based on the total weight of the composition;

(d) about 30 to about 200 mM of a buffer sufficient to maintain pH in the range of from about 4.5 to about 6.5;

(e) up to about 0.5 wt % of a surfactant, based on the total weight of the composition; and

(f) about 10 to about 20 wt % of a mediator, based on the total weight of the composition.

19. The reagent composition of claim 18, further comprising about 5 to about 50 mM of calcium chloride.

20. The reagent composition of claim 18, wherein the bias associated therewith is within ±

10%.

21. The reagent composition of claim 18, wherein the bias associated therewith is within ±

5% for samples having ≦

400 mg/dL glucose.

22. A reagent composition for making electrochemical biosensors comprising:

(a) glucose dehydrogenase (GDH) and co-factor pyrrolo-quinoline quinone (PQQ) for oxidizing glucose in a biological sample;

(b) 2 to about 10 wt % of a hydroxyethyl cellulose polymer;

(c) amorphous untreated silica powder;

(d) a calcium acetate buffer sufficient to maintain pH in the range of from about 4.5 to about 6.5;

(e) an alkyl aryl polyether alcohol surfactant; and

(f) a potassium ferricyanide mediator.

23. The reagent composition of claim 22, further comprising calcium chloride.

24. The reagent composition of claim 22, wherein the bias associated therewith is within ±

10%.

25. The reagent composition of claim 22, wherein the bias associated therewith is within ±

5% for samples having ≦

400 mg/dL glucose.

26. A reagent composition for making electrochemical biosensors comprising:

(a) an enzyme for oxidizing glucose in a biological sample;

(b) 2 to about 10 wt % of a hydrophilic polymer selected from cellulose derivatives, based on the total weight of the composition;

(c) about 1 to about 6 wt % of a thickening agent selected from the group consisting of amorphous untreated silica powder, talc, mica, diatomaceous earth, and natural and modified clays, based on the total weight of the composition;

(d) a buffer sufficient to maintain pH in the range of from about 4.5 to about 6.5;

(e) a surfactant; and

(f) a mediator.

27. The reagent composition of claim 26, wherein the bias associated therewith is within ±

10%.

28. The reagent composition of claim 26, wherein the bias associated therewith is within ±

5% for samples having ≦

400 mg/dL glucose.