Low oxygen in vivo analyte sensor

• US 9,155,496 B2
• Filed: 02/18/2011
• Issued: 10/13/2015
• Est. Priority Date: 03/04/1997
• Status: Expired due to Term

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Shults, Mark, Rhodes, Rathburn K., Updike, Stuart J., Brauker, James H.
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): MESSERSMITH, ERIC J
• Application Number:
  US13/031,063
• Publication Number:
  US 20110144465A1
• Time in Patent Office: 1,698 Days
• Field of Search: 600/345, 600/347, 600/365
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/14 Devices for taking samples of blood hypodermic syringes A61M5/00; Measuring characteristics of blood in vivo, e.g. gas concentration within the blood, pH-value of blood measuring of blood pressure A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/1411 by percutaneous method, e.g. by lancet
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• 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 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/6849 in combination with a needle set

Abstract

The present invention relates generally to systems and methods for measuring an analyte in a host. More particularly, the present invention relates to systems and methods for transcutaneous and subcutaneous measurement of glucose in a host.

Claims

1. A transcutaneous glucose monitoring system comprising:

an in vivo portion and an ex vivo portion;

wherein the in vivo portion comprises;

an implantable body comprising an electrode configured to measure a glucose level in a host;

a membrane disposed over the electrode and configured to limit transport of glucose to the electrode, wherein the membrane comprises polyurethaneurea, wherein the membrane is configured to provide the system with substantial linearity at glucose concentration of up to 400 mg/dL at an oxygen concentration of 0.45 mg/L;

a layer comprising an enzyme configured to catalyze a reaction of glucose and oxygen from a biological fluid surrounding the membrane; and

wherein the ex vivo portion comprises a sensor electronics unit operably connected to the electrode and configured to measure a current produced by the electrode.

2. The transcutaneous glucose monitoring system of claim 1, wherein the sensor electronics unit is configured to directly measure the current produced by the electrode.

3. The transcutaneous glucose monitoring system of claim 1, further comprising a biointerface membrane configured to support tissue ingrowth.

4. The transcutaneous glucose monitoring system of claim 1, further comprising an analog-to-digital converter configured to translate the current into a digital signal.

5. The transcutaneous glucose monitoring system of claim 1, wherein the electrode comprises an exposed electroactive working electrode surface with a surface area of from about 0.00002 in² to about 0.0079 in².

6. The transcutaneous glucose monitoring system of claim 1, wherein the membrane comprises a resistance domain configured to have a permeability ratio of at least about 50:

1 of glucose to an interferant.

7. The transcutaneous glucose monitoring system of claim 1, wherein the membrane comprises a resistance domain configured to have a permeability ratio of at least about 200:

1 of glucose to an interferant.

8. The transcutaneous glucose monitoring system of claim 1, wherein the sensor system is configured to have, in operation, a sensitivity of from about 1 pA/mg/dL to about 100 pA/mg/dL.

9. The transcutaneous glucose monitoring system of claim 1, wherein the sensor system is configured to have, in operation, a sensitivity of from about 5 pA/mg/dL to about 25 pA/mg/dL.

10. The transcutaneous glucose monitoring system of claim 1, wherein the sensor system is configured to have, in operation, a sensitivity of from about 3.5 to about 7.5 pA/mg/dL.

11. The transcutaneous glucose monitoring system of claim 1, wherein the sensor electronics unit is configured to measure glucose at an oxygen concentration of less than about 0.3 mg/L.

12. The transcutaneous glucose monitoring system of claim 1, wherein the sensor electronics unit is configured to measure glucose at an oxygen concentration of less than about 0.15 mg/L.

13. The transcutaneous glucose monitoring system of claim 1, wherein the sensor electronics unit is configured to measure glucose at an oxygen concentration of less than about 0.05 mg/L.

14. The transcutaneous glucose monitoring system of claim 1, wherein the sensor electronics unit is configured to measure glucose at an oxygen concentration of less than about 0.02 mg/L.

15. The transcutaneous glucose monitoring system of claim 1, wherein the membrane is configured to provide the system with substantial linearity at glucose concentration of up to 400 mg/dL at oxygen concentration of 0.4 mg/L.

16. The transcutaneous glucose monitoring system of claim 1, wherein the membrane is configured to provide the system with substantial linearity at glucose concentration of up to 400 mg/dL at oxygen concentration of 0.3 mg/L.

17. The transcutaneous glucose monitoring system of claim 1, wherein the membrane is configured to provide the system with substantial linearity at glucose concentration of up to 400 mg/dL at oxygen concentration of 0.2 mg/L.

18. The transcutaneous glucose monitoring system of claim 1, wherein the ex vivo portion further comprises a mounting unit adhered to a skin of the host, wherein the implantable body is configured to extend from inside a body of the host to the mounting unit.