Reagents and methods for detecting analytes

• US 10,696,998 B2
• Filed: 08/21/2017
• Issued: 06/30/2020
• Est. Priority Date: 12/10/2007
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Inventors: Chu, Amy H., Marfurt, Karen L., Tudor, Brenda L., Warchal-Windham, Mary Ellen, Zhu, Boru
• Primary Examiner(s): Dinh, Bach T
• Application Number:
  US15/682,182
• Publication Number:
  US 20170349929A1
• Time in Patent Office: 1,044 Days
• 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: 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 for detecting an analyte comprises a flavoprotein enzyme, a mediator such as a phenothiazine mediator, at least one surfactant, a polymer and a buffer. The reagent may be used with an electrochemical test sensor that includes a plurality of electrodes.

Claims

1. An electrochemical test sensor comprising:

a working electrode having a surface;

a counter electrode having a surface; and

a reagent coating at least a portion of the surface of the working electrode and at least a portion of the surface of the counter electrode, the reagent comprising FAD-glucose dehydrogenase, a 3-(2′

,5′

-disulfophenylimino)-3H-phenothiazine mediator having about 5 wt. % sulfate, a phosphate buffer, a surfactant, and a hydroxyethyl cellulose polymer, wherein at least one of the mediator and the buffer includes an inorganic salt, and a ratio of the total inorganic salt to mediator is less than about 3;

1.

2. The sensor of claim 1, wherein the ratio of the total inorganic salt to mediator is in a ratio of less than about 2:

1.

3. The test sensor of claim 1, wherein the reagent includes about 2.00 U/μ

L of the FAD-glucose dehydrogenase enzyme, about 40 mM of the 3-(2′

,5′

-disulfophenylimino)-3H-phenothiazine enzyme, about 50 mM of the buffer, about 0.20 wt. % of heptanoyl-N-methylglucamide surfactant, and about 0.25 wt. % of the hydroxyethyl cellulose polymer.

4. The test sensor of claim 1, wherein the buffer is a phosphate buffer, the reagent including about 30 mM of the phosphate buffer.

5. The test sensor of claim 1, wherein the FAD-glucose dehydrogenase has an activity of from about 0.5 Units/μ

L to about 2.5 Units/μ

L, the 3-(2′

,5′

-disulfophenylimino)-3H-phenothiazine mediator has a concentration of from about 30 mM to about 60 mM, the surfactant being a heptanoyl-N-methylglucamide surfactant having a concentration of from about 0.1 wt. % to about 0.4 wt. % of the reagent, and the hydroxyethyl cellulose polymer has a concentration of from about 0.2 wt. % to about 0.5 wt. % of the reagent.

6. The test sensor of claim 1, wherein the FAD-glucose dehydrogenase has an activity of about 1.75 Units/μ

L, the 3-(2′

,5′

-disulfophenylimino)-3H-phenothiazine mediator has a concentration of about 40 mM, the surfactant having a concentration of about 0.2 wt. %, the hydroxyethyl cellulose has a concentration of about 0.25 wt. %, and the buffer being a phosphate buffer having a concentration of about 100 mM.

7. The test sensor of claim 6, wherein the coefficient of variation of the reagent is between about 1.2 and about 3.4.

8. The test sensor of claim 1, wherein the buffer is a phosphate buffer, the reagent including about 50 mM of the phosphate buffer at a pH of about 6.5, about 0.25% of the hydroxyethyl cellulose polymer, about 0.2% of heptanoyl-N-methylglucamide surfactant, and about 40 mM of the 3-(2′

,5′

-disulfophenylimino)-3H-phenothiazine mediator, wherein the FAD-glucose dehydrogenase has an activity of about 2 Units/μ

L, and wherein the coefficient of variation of the reagent is between about 1.4 and about 2.7.