Sensor with improved shelf life

• US 7,335,292 B2
• Filed: 07/29/2003
• Issued: 02/26/2008
• Est. Priority Date: 03/20/1998
• Status: Expired due to Fees

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Hodges, Alastair McIndoe, Chatelier, Ronald
• Primary Examiner(s): Olsen; Kaj K.
• Application Number:
  US10/630,441
• Publication Number:
  US 20040069657A1
• Time in Patent Office: 1,673 Days
• Field of Search: 204/400, 204/403.01, 204/280, 204/290.01, 204/290.11, 205/775, 427/2.11
• US Class Current: 205/775
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61N 1/0476 Array electrodes (including any electrode arrangement with more than one electrode for at least one of the polarities)
• CPC Class Codes: A61N 1/0492 Patch electrodes A61N1/0412, A61N1/0428 take precedence
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: G01N 27/30 Electrodes, e.g. test electrodes; Half-cells G01N27/414 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

The present invention provides a metal electrode stabilized by a coating, the coating comprising a sulfur containing moiety in its molecular structure. The coating may also include a hydrophilic group and a spacer between the sulfur containing moiety and the hydrophilic group. Preferably, the sulphur-containing moiety is selected from the group comprising thiol, disulphide and SOx, and the hydrophilic group is selected from the group comprising hydroxyl, amine, carboxyl, carbonyl, oligo (ethylene oxide) chain, and zwitterionic species. Compounds useful in the present invention include 2-mercaptoethanol, 2-mercaptoethylamine, 3-mercaptopropionic acid, thiophene, 4-carboxythiophene, cysteine, homocysteine, and cystine.

Claims

1. A coated metal electrode, the metal electrode comprising a coating and an overcoating, wherein the overcoating comprises a surfactant, wherein the coating comprises a sulfur containing moiety in its molecular structure, wherein

the coating does not result in a loss of the sensing characteristics of the electrode, and wherein;

the coating is selected from the group consisting of 2-mercaptoethanol, 2-mercaptoethylamine, thiophene, L-cysteine, L-cystine, D-cysteine, D-cystine, L-homocysteine, D-homocysteine, and wherein;

a temporal stability of the coated metal electrode is greater than a temporal stability of a corresponding uncoated metal electrode.

2. The coated metal electrode according to claim 1, wherein the compound is a stereospecific compound.

3. The coated metal electrode according to claim 2, wherein the stereospecific compound comprises a mixture of D isomers and L isomers.

4. The coated metal electrode according to claim 2, wherein the stereospecific compound comprises a D isomer.

5. The coated metal electrode according to claim 2, wherein the stereospecific compound comprises an L isomer.

6. A method of preparing a metal electrode stabilized by a coating, the method comprising:

contacting a metal electrode with a substance comprising a sulfur containing moiety in its molecular structure; and

thereafter contacting the metal electrode with a surfactant, whereby a coated metal electrode is obtained, wherein

the coating does not result in a loss of the sensing characteristics of the electrode, and wherein;

the coating is selected from the group consisting of 2-mercaptoethanol, 2-mercaptoethylamine, 3-mercaptopropionic acid, thiophene, L-cysteine, L-cystine, D-cysteine, D-cystine, L-homocysteine, D-homocysteine, and wherein

a temporal stability of the coated metal electrode is increased relative to that of a corresponding uncoated metal electrode.

7. The method of claim 6, wherein the coating further comprises a stereospecific compound.

8. The method of claim 7, wherein the stereospecific compound comprises a mixture of D isomers and L isomers.

9. The method of claim 7, wherein the stereospecific compound comprises a D isomer.

10. The method of claim 7, wherein the stereospecific compound comprises an L isomer.

11. A method of sensing an analyte, the method comprising:

contacting a sample comprising an analyte to a metal electrode, the metal electrode comprising a coating and an overcoating, wherein the overcoating comprises a surfactant, wherein the coating comprises a sulfur containing moiety in its molecular structure, wherein

the coating does not result in a loss of the sensing characteristics of the electrode, and wherein;

the coating is selected from the group consisting of 2-mercaptoethanol, 2-mercaptoethylamine, 3-mercaptopropionic acid, thiophene, L-cysteine, L-cystine, D-cysteine, D-cystine, L-homocysteine, D-homocysteine, and wherein

a temporal stability of the coated metal electrode is greater than a temporal stability of a corresponding uncoated metal electrode; and

obtaining a measurement indicative of a presence of the analyte in the sample.

12. The method of claim 11, wherein the coating further comprises a stereospecific compound.

13. The method of claim 12, wherein the stereospecific compound comprises a mixture of D isomers and L isomers.

14. The method of claim 12, wherein the stereospecific compound comprises a D isomer.

15. The method of claim 12, wherein the stereospecific compound comprises an L isomer.