Subcutaneous Glucose Electrode

• US 20090137889A1
• Filed: 11/12/2008
• Published: 05/28/2009
• Est. Priority Date: 03/04/1991
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Heller, Adam, Pishko, Michael V.
• Granted Patent: US 8,414,749 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: C12Q 1/002 Electrode membranes
• 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: Y10S 435/817 Enzyme or microbe electrode

Abstract

A small diameter flexible electrode designed for subcutaneous in vivo amperometric monitoring of glucose is described. The electrode is designed to allow “one-point” in vivo calibration, i.e., to have zero output current at zero glucose concentration, even in the presence of other electroreactive species of serum or blood. The electrode is preferably layered, with the layers serially deposited within a recess upon the tip of a polyamide insulated gold wire. A first glucose concentration-to-current transducing layer can be overcoated with an electrically insulating and glucose flux limiting layer (second layer) on which, optionally, an immobilized interference-eliminating horseradish peroxidase based film is deposited. An outer layer is preferably biocompatible.

Claims

1. An analyte sensor comprising:

one or more working electrodes; and

an analyte-responsive sensing layer associated with and in electrical contact with the one or more working electrodes, the sensing layer comprising an enzyme,

wherein at least a portion of the sensor is adapted to be subcutaneously positioned in a subject.

2. The analyte sensor of claim 1, wherein the analyte is glucose and the enzyme is glucose oxidase.

3. The analyte sensor of claim 1, wherein the enzyme is non-leachable.

4. The analyte sensor of claim 1, the sensing layer further comprising a redox compound.

5. The analyte sensor of claim 4, wherein the redox compound is non-leachable.

6. The analyte sensor of claim 5, wherein the enzyme is non-leachable.

7. The analyte sensor of claim 1, further comprising a diffusion-limiting layer.

8. The analyte sensor of claim 7, wherein the diffusion-limiting layer is adapted to limit the rate of analyte transport to the sensing layer.

9. The analyte sensor of claim 7, further comprising one or more additional layers.

10. The analyte sensor of claim 9, wherein the one or more additional layers comprises at least one of a biocompatible layer or an interferant eliminating layer

11. The analyte sensor of claim 1, wherein the sensor comprises a portion adapted for positioning external to the subject and a portion adapted for subcutaneous positioning in the subject.

12. The analyte sensor of claim 11, wherein the portion adapted for external positioning is adapted for connection to a device for measurement of the electrical signal generated by the sensor.

13. The analyte sensor of claim 1, wherein the sensor has substantially no signal output when the concentration of glucose is zero.

14. The analyte sensor of claim 1, wherein the sensor comprises at least two electrodes and at least one of the electrodes is a working electrode and at least one other electrode is a reference electrode, a counter electrode or a combined reference and counter electrode.

15. The analyte sensor of claim 1, wherein one or more working electrodes is a wire.

18. A method of measuring the concentration of an analyte in a subject, the method comprising:

contacting body fluid of the subject with the analyte sensor of claim 1 to generate an electrical signal; and

determining from the generated electrical signal the concentration of the analyte in the body fluid.

19. The method of claim 18, wherein the contacting includes positioning at least a portion of the sensor subcutaneously in the subject.

20. The method of claim 18, wherein the analyte is glucose.

16. An analyte sensor comprising:

an electrode comprising a metal wire; and

an analyte-responsive sensing layer associated with the wire, the sensing layer comprising an enzyme.

17. The analyte sensor of claim 16, wherein at least a portion of the sensor is adapted for subcutaneous insertion in a subject.