DUAL ELECTRODE SYSTEM FOR A CONTINUOUS ANALYTE SENSOR

• US 20090076356A1
• Filed: 11/03/2008
• Published: 03/19/2009
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Rixman, Monica A., Brauker, James H., Nicholas, Melissa A., Petisce, James R., Simpson, Peter C., Woo, Kum Ming, Rhodes, Rathburn K., Goode, Paul V., Tapsak, Mark A., Kamath, Apurv U., Burd, John, Boock, Robert J.
• Granted Patent: US 7,896,809 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• 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

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 analyte or non-analyte related signal, both of which electrode include an interference domain.

Claims

1. An continuous glucose monitoring system configured for measuring glucose in a host, the system comprising:

a continuous glucose sensor comprising;

a first working electrode configured to generate a first signal indicative of glucose and non-glucose related electroactive compounds having a first oxidation potential; and

a second working electrode configured to generate a second signal indicative of non-glucose related electroactive compounds having the first oxidation potential; and

electronics configured to process the first signal and the second signal;

wherein the sensor further comprises at least two mechanisms configured to substantially block or substantially eliminate noise in the sensor signal, the mechanisms comprising a first mechanism disposed on the sensor and configured to reduce or substantially block interferants from reaching the first working electrode and the second working electrode, and a second mechanism in the electronics comprising programming configured to process the first signal to substantially eliminate a signal associated with the non-glucose related electroactive compounds therefrom.

2. The system of claim 1, wherein the first mechanism comprises an interference domain.

3. The system of claim 1, wherein the first mechanism comprises a mechanism configured to increase flow around at least a portion of the sensor.

4. The system of claim 3, wherein the first mechanism comprises a physical spacer.

5. The system of claim 1, wherein the first mechanism comprises at least one mechanism selected from the group consisting of a hydrogel, a scavenging agent, a bioactive agent, a shedding layer, and an interferent scavenger.

6. The system of claim 1, wherein the first mechanism comprises an auxiliary electrode configured to electrochemically modify electrochemical interferants to render them substantially non-electroactively reactive at the first working electrode and the second working electrode.

7. The system of claim 1, wherein the non-glucose related electroactive compounds having a first oxidation potential comprise non-constant non-glucose related compounds.

8. The system of claim 1, wherein the second mechanism comprises a module associated with the electronics configured to subtract a second measured at the second electrode from a signal measured at the first electrode, whereby a differential signal comprising at least one glucose sensor data point is determined.

9. The system of claim 1, the second mechanism comprises a differential amplifier configured to electronically subtract a signal measured at the second electrode from a signal measured at the first electrode.

10. The system of claim 1, wherein the second mechanism comprises at least one of hardware and software configured to digitally subtract a signal measured at the second electrode from a signal measured at the first electrode.

11. A method for providing a substantially noise-free signal for a glucose sensor implanted in a host, the method comprising:

implanting a glucose sensor in a host, the glucose sensor comprising;

a first working electrode disposed beneath an active enzymatic portion of a sensor membrane;

and a second working electrode disposed beneath an inactive-enzymatic or a non-enzymatic portion of a sensor membrane, wherein the sensor is configured to substantially block one or more interferants from reaching the first working electrode and the second working electrode;

generating a first signal indicative of glucose and non-glucose related electroactive compounds having a first oxidation potential;

generating a second signal indicative of non-glucose related electroactive compounds having the first oxidation potential; and

processing the first signal to substantially eliminate the signal associated with the non-glucose related electroactive compounds therefrom.