Micro-band electrode

• US 7,972,487 B2
• Filed: 12/23/2002
• Issued: 07/05/2011
• Est. Priority Date: 12/21/2001
• Status: Expired due to Fees

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG)
• Inventors: Lorimer, Kevin, Astier, Yann, Butler, Ronald Neil, Hyland, Mark, Wallace-Davis, Emma Naomi Kathlene
• Primary Examiner(s): Ruddock; Ula C
• Assistant Examiner(s): BALL, JOHN C
• Application Number:
  US10/499,129
• Publication Number:
  US 20050178674A1
• Time in Patent Office: 3,116 Days
• Field of Search: 205/775, 204/403.14, 204/403.13, 204/403.01, 204/403.09
• US Class Current: 204/403.14
• 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 29/49002 Electrical device making

Abstract

The invention concerns an electrochemical cell which, either alone or together which a substrate onto which it is placed, is in the form of a receptacle. The electrochemical cell contains a working electrode and a counter electrode, the working electrode being in a wall of the receptacle. At least one of the electrodes has at least one dimension of less than 50 μm. The electrochemical cell is principally intended for use as a micro-electrode suitable for screening water, blood, urine or other biological or non-biological fluids.

Claims

1. An electrochemical cell in the form of a receptacle, said cell comprising a counter electrode and a working electrode, wherein the minimum distance between the working electrode and the counter electrode is 50 μ

m, wherein at least one electrode is a micro-electrode having one dimension of less than 50 μ

m and one dimension of greater than 50 μ

m, wherein the working electrode is in a wall of the receptacle, and wherein the receptacle contains an electro-active substance, and wherein the receptacle is shaped so as to restrict movement of the electro-active substance away from the electrodes when a sample flows over the electrochemical cell.

2. An electrochemical cell according to claim 1, wherein the working electrode is in the form of a continuous band.

3. An electrochemical cell according to claim 1, which further comprises a reference electrode.

4. An electrochemical cell according to claim 1, wherein the ratio of the surface area of the counter electrode to the surface area of the working electrode is at least 25:

1.

5. An electrochemical cell according to claim 1, wherein the working electrode is a micro-electrode having at least one dimension in the range of 0.1 to 20 μ

m.

6. An electrochemical cell according to claim 1, wherein the receptacle has a width, or in the case of a cylindrical receptacle a diameter, of from 0.1 to 5 mm.

7. An electrochemical cell according to claim 1, wherein the minimum distance between the counter electrode and the working electrode is from 50 to 1000 μ

m.

8. An electrochemical cell according to claim 1, wherein a base and/or a wall or walls of the receptacle contain one or more air-outlet channels.

9. An electrochemical cell according to claim 1, wherein the electro-active substance has been dried.

10. An electrochemical cell according to claim 1, wherein the electro-active substance comprises an enzyme.

11. An electrochemical cell according to claim 1, wherein the base of the receptacle comprises an electro-active substance.

12. An electrochemical cell according to claim 1, wherein the base of the receptacle comprises a membrane, said membrane comprising an electro-active substance.

13. An electrochemical cell according to claim 1, wherein the open end of the receptacle is at least partly covered by a permeable membrane.

14. An electrochemical cell according to claim 13 wherein the permeable membrane comprises an electro-active substance.

15. An electrochemical cell according to claim 1, wherein the receptacle comprises one or more capillary flow channels through which a sample may enter.

16. An electrochemical cell according to claim 1, wherein the counter electrode forms at least a part of a base of the receptacle.

17. An electrochemical cell according to claim 15, wherein the receptacle is covered by a layer containing the counter electrode.

18. An electrochemical cell according to claim 1, wherein the counter electrode is in a wall or walls of the receptacle.

19. An electrochemical cell according to claim 1 which is suitable for screening liquid samples.

20. A multi-analyte device comprising a plurality of electrochemical cells according to claim 1.

21. A process for producing an electrochemical cell according to claim 1, which process comprises the steps of:

(a) forming a first part comprising an insulating material which is optionally coated with a counter electrode layer;

(b) forming a second part comprising a laminate of a working electrode layer between two layers of an insulating material;

(c) creating a hole in the second part; and

(d) bonding said first part to said second part to form a receptacle, which process further comprises placing an electro-active substance into the receptacle and optionally drying the electro-active substance, and wherein the receptacle is shaped so as to restrict movement of the electro-active substance away from the electrodes when a sample flows over the electrochemical cell.

22. A process according to claim 21 wherein the second part comprises a laminate of a counter electrode layer between two layers of insulating material.

23. A process according to claim 21 wherein the first part comprises an electro-active substance.

24. A process according to claim 21, which further comprises placing a membrane over at least a part of the open end of the receptacle.

25. A process according to claim 21, wherein step (c) comprises forming two or more holes in said second part, in order to form a multi-analyte device.

26. A process according to claim 21 which comprises the steps of:

(a) forming a first part comprising an insulating material;

(b) forming a second part comprising a laminate of a working electrode layer between two layers of an insulating material;

(c) creating, in the second part, a hole and a capillary channel to allow a sample to enter said hole;

(d) bonding said first part to said second part to form a receptacle;

(e) placing an electro-active substance into the receptacle and optionally drying the electro-active substance; and

(f) bonding to the open end of said receptacle a layer which is optionally coated with a counter electrode material.

27. A process according to claim 26, wherein step (c) comprises forming, in said second part, two or more holes and two or more capillary channels to allow a sample to enter said two or more holes, and wherein step (e) comprises inserting an electro-active substance, which may be identical or different, into one or more of the receptacles formed in step (d), in order to form a multi-analyte device.

28. A process according to claim 21, wherein one or more of the electrodes is formed by screen or inkjet printing onto a substrate.

30. A multi-analyte device comprising a plurality of electrochemical cells as defined in claim 13.

31. An electrochemical cell according to claim 1, wherein the ratio of the surface area of the counter electrode to the surface area of the working electrode is about 1:

1.

32. An electrochemical cell according to claim 1, wherein the ratio of the surface area of the counter electrode to the surface area of the working electrode is from 1:

1 to 25;

1.

33. An electrochemical cell according to claim 1, wherein the working electrode is a micro-electrode having at least one dimension of less than 25 μ

m.

34. An electrochemical cell according to claim 1, wherein the receptacle has a width, or in the case of a cylindrical receptacle a diameter, of at least about 1 mm.

35. A process according to claim 21, wherein the step of creating a hole in the second part comprises a laser drilling step.

29. A method of electrochemically testing one or more compounds of a sample, the method comprising the steps of:

(a) providing an electrochemical cell in the form of a receptacle, said cell comprising a counter electrode and a working electrode, wherein the minimum distance between the working electrode and the counter electrode is 50 μ

m, wherein at least one electrode is a micro-electrode having one dimension of less than 50 μ

m and one dimension of greater than 50 μ

m, wherein the working electrode is in a wall of the receptacle, wherein the receptacle contains an electro-active substance, and wherein the receptacle is shaped so as to restrict movement of the electro-active substance away from the electrodes when a sample flows over the electrochemical cell;

(b) inserting the sample into the electrochemical cell;

(c) applying a voltage or a current between the working and counter electrodes; and

(d) measuring the resulting current, voltage or charge across the working and counter electrodes.