Biosensor electrode mediators for regeneration of cofactors

• US 8,414,760 B2
• Filed: 07/30/2012
• Issued: 04/09/2013
• Est. Priority Date: 10/16/1997
• Status: Expired due to Fees

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Laboratories Incorporated
• Inventors: Forrow, Nigel J., Sanghera, Gurdial S., Watkin, Jared L., Walters, Stephen
• Primary Examiner(s): Ball, J. Christopher
• Assistant Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US13/561,933
• Publication Number:
  US 20130031780A1
• Time in Patent Office: 253 Days
• Field of Search: 20440301-40315, 600309-367, 205/775, 205/777.5, 205/778, 205/792
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/005 involving specific analytes or enzymes including groups of enzymes, e.g. oxydases; C12Q1/004 takes precedence
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

The present invention is based on the discovery of NAD⁺ and NADP⁺ mediator compounds that do not bind irreversibly to thiol groups in the active sites of intracellular dehydrogenase enzymes. Such mediator compounds avoid a common mode of enzyme inhibition. The mediators can therefore increase the stability and reliability of the electrical response in amperometric electrodes constructed from NAD- or NADP-dependent enzymes.

Claims

1. A method of making an electrochemical sensor, the method comprising:

applying a plurality of electrodes onto the surface of a substrate;

applying a conductive ink to one or more of the plurality of electrodes, wherein the conductive ink comprises an analyte-responsive enzyme and a mediator compound wherein the mediator compound is one of the following two formulae;

2. The method according to claim 1, wherein the mediator is 1,10-phenanthroline-5,6-dione or a derivative thereof.

3. The method according to claim 1, wherein applying a plurality of electrodes further comprises applying a dummy electrode.

4. The method according to claim 1, wherein the conductive ink further comprises a filler and a binder.

5. The method according to claim 1, wherein applying a plurality of electrodes comprises screen printing the plurality of electrodes.

6. The method according to claim 1, wherein the analyte responsive enzyme is a nicotiamide cofactor-dependent enzyme.

7. The method according to claim 6, wherein the analyte responsive enzyme is selected from the group consisting of alcohol dehydrogenase, lactate dehydrogenase, 3-hydroxybutyrate dehydrogenase, glucose-6-phosphate dehydrogenase, glucose dehydrogenase, formaldehyde dehydrogenase, malate dehydrogenase and 3-hydroxysteroid dehydrogenase.

8. The method according to claim 7, wherein the analyte responsive enzyme is glucose dehydrogenase or 3-hydroxybutyrate dehydrogenase.

9. The method according to claim 1, wherein the conductive ink further comprises a nicotinamide cofactor.

10. The method according to claim 9, wherein the nicotinamide cofactor is NADH or NADPH.

11. The method according to claim 1, further comprising applying a cover layer defining an enclosed space over the electrodes, the cover layer having an aperture for receiving a sample into the enclosed space.

12. The method according to claim 11, further comprising applying a least one layer of mesh interposed in the enclosed space between the cover layer and the electrodes.

13. The method according to claim 1, wherein applying a plurality of electrodes comprises applying a working electrode, a reference electrode/counter electrode and a fill indicator electrode.

14. The method according to claim 13, wherein the method comprises positioning the plurality of electrodes to present a combined effective area that ranges from 5 mm² to 25 mm².