Electrochemical test strip for use in analyte determination

• US 6,716,577 B1
• Filed: 02/02/2000
• Issued: 04/06/2004
• Est. Priority Date: 02/02/2000
• Status: Expired due to Term

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Shah, Mahesh, Yu, Yeung Siu
• Primary Examiner(s): FORMAN, BETTY J
• Application Number:
  US09/497,269
• Time in Patent Office: 1,525 Days
• Field of Search: 435/289.1, 435/14, 435/6, 435/25, 435/7.1, 435/176, 204/403, 422/50, 422/55, 422/58, 422/62, 422/68
• US Class Current: 435/6.11
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: G01N 33/5438 Electrodes

Abstract

Electrochemical test strips and methods for their use in the detection of an analyte in a physiological sample are provided. The subject test strips have a reaction zone defined by opposing metal electrodes separated by a thin spacer layer. The metal surface of at least one of the electrodes is modified by a homogenous surface modification layer made up of linear self-assembling molecules having a first sulfhydryl end group and a second sulfonate end group separated by a short chain alkyl linking group, where 2-mercaptoethane sulfonic acid or a salt thereof is preferred in certain embodiments. The subject electrochemical test strips find application in the detection of a wide variety of analytes, and are particularly suited for use the detection of gluose.

Claims

1. An electrochemical test strip comprising:

(a) a reaction zone defined by opposing working and reference electrodes separated by a spacer layer, wherein at least one of said working and reference electrodes has a surface modified with a homogenous surface modification layer made up of self assembling molecules having a first sulfhydryl end group and a second sulfonate end group, wherein said sulfhydryl and sulfonate end groups are separated by a lower alkyl linker group wherein all the self-assembling molecules are identical; and

(b) a redox reagent system present in said reaction zone, wherein said redox reagent system comprises at least one enzyme and a mediator.

2. The electrochemical test strip according to claim 1, wherein at least one of said electrodes comprises a metal selected from the group consisting of:

gold, palladium, silver, iridium, carbon, doped indium tin oxide and stainless steel.

3. The electrochemical test strip according to claim 2, wherein said electrode comprises gold or palladium.

4. The electrochemical test strip according to claim 1, wherein said self-assembling molecules have the formula:

5. The electrochemical test strip according to claim 1, wherein said at least one enzyme includes an oxidizing enzyme.

21. The elestrochemical test strip according to claim 1, wherein said strip is present in an automated instrument designed to work with test strips.

6. An electrochemical test strip comprising:

(a) a reaction zone defined by opposing working and reference electrodes comprising a metal surface separated by a thin spacer layer, wherein at least one of said working and reference electrodes has a surface modified with a homogenous surface modification layer made up of self assembling molecules wherein all the self-assembling molecules are identical of the formula;

7. The electrochemical test strip according to claim 6, wherein said reaction zone has a volume ranging from about 0.1 to 10 μ

l.

8. The electrochemical test strip according to claim 6, wherein said metal is selected from the group consisting of gold and palladium.

9. The electrochemical test strip according to claim 6, wherein said enzymes include an oxidizing enzyme.

10. The electrochemical test strip according to claim 9, wherein said oxidizing enzyme is a glucose oxidizing enzyme.

11. The electrochemical test strip according to claim 6, wherein said self assembling molecule is 2-mercaptoethane sulfonic acid or a salt thereof.

12. An electrochemical test strip for use in detecting the concentration of glucose in a physiological sample, said test strip comprising:

(a) a reaction zone defined by opposing working and reference electrodes each comprising a metal surface selected from the group consisting of gold and palladium separated by a thin spacer layer, wherein at least one of said working and reference electrodes has a surface modified with a homogenous surface modification layer made up of 2-mercaptoethane sulfonic acid or a salt thereof wherein all the self-assembling molecules are identical; and

(b) a redox reagent system present in said reaction zone, wherein said redox reagent system comprises a glucose oxidizing enzyme and a mediator.

13. The electrochemical test strip according to claim 12, wherein said reaction zone has a volume ranging from about 0.1 to 10 μ

l.

14. The electrochemical test strip according to claim 12, wherein said reference electode is a gold electrode.

15. The electrochemical test strip according to claim 12, wherein said working electrode is a palladium electrode.

16. A method of determining the concentration of an analyte in a physiological sample, said method comprising:

(a) applying said physiological sample to an electrochemical test strip comprising;

(i) a reaction zone defined by opposing working and reference metallic electrodes separated by a spacer layer, wherein at least one of said metallic working and reference electrodes has a surface modified with a homogenous surface modification layer made up of self assembling molecules having a first sulfhydryl end group and a second sulfonate and group, wherein said, sulfhydryl and sulfonate end groups are separated by a lower alkyl linker group wherein all the self-assembling molecules are identical; and

(ii) a redox reagent system present in said reaction zone, wherein said redox reagent system comprises at least one enzyme and a mediator;

(b) detecting an electrical signal in said reaction zone using said metallic electrodes; and

(c) measuring said detected electrical signal to thereby determine the concentration of said analyte in said sample.

17. The method according to claim 16, wherein said self-assembling molecules have the formula:

18. The method according to claim 17, wherein said self-assembling molecules are 2-mercaptoethane sulfonic acid or a salt thereof.

19. The method according to claim 16, wherein said analyte is glucose.

20. The method according to claim 19, wherein said redox reagent system comprises a glucose oxidizing enzyme.

22. The method according to claim 16, wherein said detecting and measuring steps are performed by an automated instrument designed to work with test strips.