Dual electrode system for a continuous analyte sensor

• US 7,366,556 B2
• Filed: 10/04/2006
• Issued: 04/29/2008
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brister, Mark, Petisce, James R., Simpson, Peter
• Primary Examiner(s): Nasser; Robert L
• Application Number:
  US11/543,683
• Publication Number:
  US 20070032717A1
• Time in Patent Office: 573 Days
• Field of Search: None
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• 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
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal

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. An analyte sensor configured for insertion into a host for measuring an analyte in the host, the sensor comprising:

a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane;

a second working electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane; and

an electrical insulator located between the first working electrode and the second working electrode, wherein the sensor comprises a physical diffusion barrier configured to structurally block a substantial amount of diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second eleetroactive surface by a structure that protrudes from a plane that intersects both the first electroactive surface and the second eleetroactive surface, wherein the structure that protrudes comprises the electrical insulator and/or an electrode.

2. The sensor of claim 1, wherein the structure that protrudes comprises the insulator.

3. The sensor of claim 1, wherein the structure that protrudes comprises a reference electrode.

4. The sensor of claim 1, wherein the sensor is a glucose sensor, and wherein the diffusion barrier is configured to substantially block diffusion of at least one of glucose and hydrogen peroxide between the first eleetroactive surface and the second electroactive surface.

5. The sensor of claim 1, further comprising at least one of a reference electrode and a counter electrode.

6. The sensor of claim 5, wherein the reference electrode or the counter electrode, together with the first working electrode, the second working electrode and the insulator, integrally form at least a portion of the sensor.

7. The sensor of claim 5, wherein the reference electrode or the counter electrode is located at a position remote from the first electroactive surface and the second electroactive surface.

8. The sensor of claim 5, wherein a surface area of the electro active surface of the reference electrode or the counter electrode is at least six times a surface area of at least one of the first electroactive surface and the second cleetroactive surface.

9. The sensor of claim 1, wherein the sensor is configured for implantation into the host.

10. The sensor of claim 9, wherein the sensor is configured for subcutaneous implantation in a tissue of the host.

11. The sensor of claim 9, wherein the sensor is configured for indwelling in a blood stream of the host.

12. The sensor of claim 1, wherein the sensor substantially continuously measures an analyte concentration in the host.

13. The sensor of claim 1, wherein the analyte sensor comprises a glucose sensor and wherein the first working electrode is configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential.

14. The sensor of claim 13, wherein the second working electrode is configured to generate a second signal associated with non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential.

15. The sensor of claim 14, wherein the non-glucose related electroactive species comprise at least one species selected from the group consisting of interfering species, non-reaction-related hydrogen peroxide, and other electroactive species.

16. The sensor of claim 1, further comprising electronics operably connected to the first working electrode and the second working electrode, and configured to provide the first signal and the second signal to generate glucose concentration data substantially without signal contribution due to non-glucose-related noise.

17. The sensor of claim 1, wherein the first working electrode, the second working electrode, and the electrical insulator integrally form a substantial portion of the sensor configured for insertion in the host.

18. The sensor of claim 17, further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode integrally form a substantial portion of the sensor configured for insertion in the host.

19. The sensor of claim 1, wherein each of the first working electrode, the second working electrode, and the electrical insulator are configured provide at least two functions selected from the group consisting of electrical conductance, insulative property, structural support, and diffusion barrier.

20. The sensor of claim 1, wherein the structure comprises a wall that separates two working electrodes.

21. The sensor of claim 1, wherein the membrane comprises an interference domain located over the first and second electroactive surfaces.

22. An analyte sensor configured for insertion into a host for measuring an analyte in the host, the sensor comprising:

a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane system;

a second working electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic or non-enzymatic portion of the membrane system; and

an insulator located between the first electroactive surface and the second electroactive surface, wherein the membrane system is configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second electroactive surface by a discontinuity of the membrane system between the first electroactive surface and the second electroactive surface.

23. The sensor of claim 22, wherein the sensor is a glucose sensor, and wherein the membrane system is configured to substantially block diffusion of at least one of glucose and hydrogen peroxide between the first electroactive surface and the second electroactive surface.

24. The sensor of claim 22, wherein the sensor is configured for implantation into the host.

25. The sensor of claim 23, wherein the sensor is configured for subcutaneous implantation in a tissue of the host.

26. The sensor of claim 23, wherein the sensor is configured for indwelling in a blood stream of the host.

27. The sensor of claim 22, wherein the sensor substantially continuously measures an analyte concentration in the host.

28. The sensor of claim 22, further comprising electronics operably connected to the first working electrode and the second working electrode, and configured to provide the first signal and the second signal to generate glucose concentration data substantially without signal contribution due to non-glucose-related noise.

29. The sensor of claim 22, wherein the first working electrode, the second working electrode, and the insulator integrally fonn a substantial portion of the sensor configured for insertion in the host.

30. The sensor of claim 28, further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode integrally form a substantial portion of the sensor configured for insertion in the host.

31. The sensor of claim 22, wherein each of the first working electrode, the second working electrode, and the insulator are configured provide at least two functions selected from the group consisting of electrical conductance, insulative property, structural support, and diffusion barrier.

32. The sensor of claim 22, wherein the membrane system comprises an interference domain located over the first and second electroactive surfaces.

33. An analyte sensor configured for insertion into a host for measuring an analyte in the host, the sensor comprising:

a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane;

a second working electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane; and

an insulator located between the first electroactive surface and the second electroactive surface, wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second electroactive surface wherein the diffusion barrier comprises a temporal diffusion barrier configured to block or avoid a substantial amount of diffusion or reaction of at least one of the analyte and the co-analyte between the first and second electroactive surfaces.

34. The sensor of claim 33, further comprising a potentiostat configured to bias the first working electrode and the second working electrode at substantially overlapping oxidation potentials, and wherein the temporal diffusion barrier comprises pulsed potentials of the first working electrode and the second working electrode to block or avoid a substantial amount of diffusion or reaction of at least one of the analyte and the co-analyte between the first electroactive surface and the second electroactive surface.

35. The sensor of claim 33, further comprising a potentiostat configured to bias the first working electrode and the second working electrode at substantially overlapping oxidation potentials, and wherein the temporal diffusion barrier comprises oscillating bias potentials of the first working electrode and the second working electrode to block or avoid a substantial amount of diffusion or reaction of at least one of the analyte and the co-analyte between the first electroactive surface and the second electroactive surface.

36. The sensor of claim 33, wherein the membrane comprises an interference domain located over the first and second electroactive surfaces.