DUAL ELECTRODE SYSTEM FOR A CONTINUOUS ANALYTE SENSOR

• US 20080214918A1
• Filed: 04/28/2008
• Published: 09/04/2008
• Est. Priority Date: 10/04/2006
• Status: Active Grant

Abstract

Disclosed herein are systems and methods for a continuous analyte sensor, such as a continuous glucose sensor. One such system utilizes first and second working electrodes to measure additional analyte or non-analyte related signal. Such measurements may provide a background and/or sensitivity measurement(s) for use in processing sensor data and may be used to trigger events such as digital filtering of data or suspending display of data.

Claims

1. A sensor configured and arranged for insertion into a host and for continuously detecting glucose in the host, the sensor comprising:

a first working electrode configured to generate a first signal having a first noise component related to a noise-causing species, the first working electrode having a first surface area; and

a second working electrode configured to generate a second signal having a second noise component related to the noise-causing species, the second working electrode having a second surface area;

wherein the first working electrode and the second working electrode are configured and arranged to integrate the first noise component and the second noise component about a circumference of the sensor.

2. The sensor of claim 1, wherein the noise-causing species comprises at least one member selected from the group consisting of externally produced H₂O₂, urea, lactic acid, phosphates, citrates, peroxides, amino acids, amino acid precursors, amino acid break-down products, nitric oxide, NO-donors, NO-precursors, reactive oxygen species, compounds having electroactive acidic, amine or sulfhydryl groups, acetaminophen, ascorbic acid, dopamine, ephedrine, ibuprofen, L-dopa, methyldopa, salicylate, tetracycline, tolazamide, tolbutamide, and triglycerides.

3. The sensor of claim 1, wherein the noise-causing species is non-constant.

4. The sensor of claim 1, wherein the first electroactive surface and the second electroactive surface are spaced a distance that allows noise caused by a local source that produces noise-causing species to be measured equivalently at the first electroactive surface and the second electroactive surface.

5. The sensor of claim 1, wherein the measurable species comprises H₂O₂.

6. The sensor of claim 1, further comprising a physical diffusion barrier.

7. The sensor of claim 1, wherein the physical diffusion barrier comprises a first resistance domain formed on the first working electrode and a second resistance domain formed on the second working electrode, wherein each of the first resistance domain and the second resistance is independently formed.

8. The sensor of claim 7, wherein the first resistance domain and the second resistance domain attenuate diffusion of the measurable species.

9. The sensor of claim 1, further comprising an insulator configured to insulate the first working electrode from the second working electrode.

10. The sensor of claim 9, wherein the sensor membrane is the insulator.

11. A continuous glucose sensor configured and arranged for insertion into a host and for detecting glucose in the host, the sensor comprising:

a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a sensor membrane, wherein the first electroactive surface is configured to measure a measurable species;

a second working electrode comprising a second electroactive surface disposed beneath at least one of an inactive enzymatic portion of the sensor membrane and a non-enzymatic portion of the sensor membrane, wherein the second electroactive surface is configured to measure said measurable species, and wherein the first electroactive surface and the second electroactive surface are spaced within a crosstalk distance of the measurable species; and

a physical diffusion barrier disposed between the first working electrode and the second working electrode, wherein the physical diffusion barrier is configured and arranged such that there is substantially no signal associated with crosstalk.

12. The sensor of claim 11, wherein the noise-causing species comprises at least one member selected from the group consisting of externally produced H₂O₂, urea, lactic acid, phosphates, citrates, peroxides, amino acids, amino acid precursors, amino acid break-down products, nitric oxide, NO-donors, NO-precursors, reactive oxygen species, compounds having electroactive acidic, amine or sulfhydryl groups, acetaminophen, ascorbic acid, dopamine, ephedrine, ibuprofen, L-dopa, methyldopa, salicylate, tetracycline, tolazamide, tolbutamide, and triglycerides.

13. The sensor of claim 11, wherein the noise-causing species is non-constant.

14. The sensor of claim 11, wherein the measurable species is H₂O₂ produced in an active enzymatic portion of a sensor membrane.

15. The sensor of claim 11, wherein the first area and the second area are each configured and arranged to integrate noise detected about a circumference of the sensor.

16. The sensor of claim 11, wherein the physical diffusion barrier comprises a discontinuous portion of the membrane disposed between the first electroactive surface and the second electroactive surface.

17. The sensor of claim 11, wherein the physical diffusion barrier comprises a first resistance domain formed on the first working electrode and a second resistance domain formed on the second working electrode, wherein the first resistance domain and the second resistance are independently formed.

18. The sensor of claim 17, wherein the first resistance domain and the second resistance domain are configured and arranged to attenuate diffusion of the measurable species.

19. The sensor of claim 11, further comprising an insulator configured to insulate the first working electrode from the second working electrode.

20. The sensor of claim 19, wherein the sensor membrane is the insulator.