Electrodes for the measurement of analytes in small sample volumes

• US 6,436,256 B1
• Filed: 03/06/2000
• Issued: 08/20/2002
• Est. Priority Date: 06/04/1997
• Status: Expired due to Term

• Current Assignee: Cambridge Sensors Limited
• Original Assignee: Cambridge Sensors Limited
• Inventors: Williams, Stephen Charles, Blair, Neil, Yon-Hin, Bernadette
• Primary Examiner(s): Warden, Sr., Robert J.
• Assistant Examiner(s): Olsen, Kaj K.
• Application Number:
  US09/445,154
• Time in Patent Office: 897 Days
• Field of Search: 204/403, 204/403.5, 204/403.06, 204/403.1, 205/777.5
• US Class Current: 204/403.06
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52

Abstract

A device, for use in the electrochemical analysis of an analyte in a small volume liquid sample, having a non-conducting substrate (1); a conductive layer, deposited on the substrate, in two parts (2a, 2b), defining a non-conducting gap (8) therebetween; an analyte-specific reagent (5) coated on the conductive layer, on one side of the gap; a reference electrode (3) on the conductive layer, on the other side of the gap; a spacer layer (4) deposited over the conductive layer; a monofilament mesh (6) coated with a surfactant or chaotropic agent, the mesh being laid over the reagent, the reference electrode and the spacer layer; and a second non-conductive layer (7) adhered to the mesh layer, but not coextensive therewith, thereby providing a sample application area (9) on the mesh.

Claims

1. A device for use in the electrochemical analysis of an analyte in a liquid sample, which comprises:

a non-conducting substrate;

a discontinuous conductive layer deposited on adjacent first and second portions, respectively, of the non-conducting substrate and defining a non-conducting gap between the first and second portions;

an analyte-specific reagent coated on the conductive layer on the first portion;

a reference electrode on the the conductive layer on the second portion;

a spacer layer deposited over the conductive layer;

a monofilament mesh coated with a surfactant or chaotropic agent, the mesh being laid over the analyte-specific reagent, the reference electrode and the spacer layer; and

a second non-conductive layer, adhered to and covering the mesh layer, said second non-conducting layer having an exterior edge such that the second non-conducting layer is not co-extensive with the mesh layer, thereby providing an exposed portion of the mesh at one exterior edge of the mesh.

2. A device according to claim 1, wherein the reagent does not contain filler having both hydrophobic and hydrophilic surface regions.

3. A device according to claim 2, wherein the analyte is glucose and the reagent is glucose dehydrogenase.

4. A device according to claim 2, wherein the mesh is additionally coated with a cell lytic agent.

5. A device according to claim 2, wherein the first conductive layer comprises graphite particles, carbon particles and a polymer binder, wherein the graphite particles have an average particle size of 1-20 μ

m and a surface area of 1-50 m²/g, and the carbon particles have an average size of 5-70 nm and a surface area of less than 150 m²/g.

6. A method for the electrochemical analysis of an analyte in a liquid sample, which comprises applying the sample to the application area on a device according to claim 2, and quantifying the analyte by reaction with the reagent.

7. A device according to claim 1, wherein the analyte is glucose and the reagent is glucose dehydrogenase.

8. A device according to claim 1, wherein the mesh is additionally coated with a cell lytic agent.

9. A device according to claim 1, wherein the first conductive layer comprises graphite particles, carbon particles and a polymer binder, wherein the graphite particles have an average particle size of 1-20 μ

m and a surface area of 1-50 m²/g, and the carbon particles have an average size of 5-70 nm and a surface area of less than 150 m²/g.

10. A method for the electrochemical analysis of an analyte in a liquid sample, which comprises applying the sample to the application area on a device according to claim 1, and quantifying the analyte by reaction with the reagent.

11. A device for use in the electrochemical analysis of an analyte in a liquid sample, which comprises:

a non-conducting substrate;

a first and a second conductive layer deposited on first and second portions, respectively, of the non-conducting substrate and defining a non-conducting gap between the first and second conductive layers;

an analyte-specific reagent coated on the first conductive layer;

a reference electrode on the second conductive layer;

a spacer layer deposited over a portion of both the first and second conductive layers;

a monofilament mesh coated with a surfactant or chaotropic agent, the mesh being laid over the analyte-specific reagent, the reference electrode and the spacer layer; and

a second non-conductive layer, adhered to and covering the mesh layer, said second non-conducting layer having an exterior edge such that the second non-conducting layer is not co-extensive with the mesh layer, thereby providing an exposed edge portion of the mesh at one exterior edge of the mesh.