Analyte sensor with increased reference capacity

• US 9,351,677 B2
• Filed: 03/04/2013
• Issued: 05/31/2016
• Est. Priority Date: 07/02/2009
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Rong, Daiting, Bohm, Sebastian, Wightlin, Matthew D.
• Primary Examiner(s): LEONG, SUSAN DANG
• Application Number:
  US13/784,523
• Publication Number:
  US 20130245412A1
• Time in Patent Office: 1,184 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/0209 Special features of electrodes classified in A61B5/24, A61B5/25, A61B5/283, A61B5/291, A61B5/296, A61B5/053
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors

Abstract

Systems and methods of use for continuous analyte measurement of a host'"'"'s vascular system are provided. In some embodiments, a continuous glucose measurement system includes an electrochemical sensor incorporating a silver/silver chloride reference electrode, wherein a capacity of the reference electrode is controlled.

Claims

1. An implantable electrochemical sensor for measuring an analyte concentration in a host, comprising:

a working electrode configured to measure a concentration of an analyte; and

a silver/silver chloride reference electrode, wherein at least a portion of the silver/silver chloride reference electrode is covered with an enzyme layer, wherein the enzyme layer is configured, in vivo, to generate hydrogen peroxide upon exposure to a substrate, whereby the hydrogen peroxide regenerates silver chloride of the reference electrode such that a reference capacity of the reference electrode is increased.

2. The implantable electrochemical sensor of claim 1, wherein the enzyme is an oxidase enzyme.

3. The implantable electrochemical sensor of claim 2, wherein the substrate is selected from the group consisting of glucose, urate, ascorbate, citrate, L-lactate, succinate, D-glucose, and ethanol.

4. The implantable electrochemical sensor of claim 1, wherein the analyte is glucose.

5. The implantable electrochemical sensor of claim 1, wherein the reference electrode comprises a chloridized elongated silver body.

6. The implantable electrochemical sensor of claim 1, further comprising a diffusion barrier configured to substantially block diffusion of hydrogen peroxide between the silver/silver chloride reference electrode and the working electrode.

7. The implantable electrochemical sensor of claim 1, wherein the enzyme layer has a thickness from about 0.01 microns to about 12 microns thick.

8. The implantable electrochemical sensor of claim 1, wherein a percentage of a surface area of the reference electrode covered with the enzyme layer is from about 10% to about 100%.

9. An electrochemical sensor for measuring an analyte concentration in a host, comprising:

a working electrode configured to measure a concentration of an analyte; and

a reference electrode, wherein at least a portion of the reference electrode is covered with an enzyme layer, wherein the enzyme layer is configured, in vivo, to generate a reference electrode regenerating species upon exposure to a substrate, whereby the reference electrode regenerating species regenerates a component of the reference electrode such that a reference capacity of the reference electrode is increased.

10. The electrochemical sensor of claim 9, wherein the enzyme is an oxidase enzyme.

11. The electrochemical sensor of claim 9, wherein the substrate is selected from the group consisting of glucose, urate, ascorbate, citrate, L-lactate, succinate, D-glucose, and ethanol.

12. The electrochemical sensor of claim 9, wherein the analyte is glucose.

13. The electrochemical sensor of claim 9, wherein the reference electrode comprises a chloridized elongated silver body.

14. The electrochemical sensor of claim 9, wherein the reference electrode regenerating species is hydrogen peroxide.

15. The electrochemical sensor of claim 9, wherein the enzyme layer has a thickness from about 0.01 microns to about 12 microns thick.

16. The electrochemical sensor of claim 9, wherein a percentage of a surface area of the reference electrode covered with the enzyme layer is from about 10% to about 100%.