DEVICE AND METHOD FOR DETERMINING ANALYTE LEVELS

• US 20100099970A1
• Filed: 12/22/2009
• Published: 04/22/2010
• Est. Priority Date: 03/04/1997
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Shults, Mark C., Updike, Stuart J., Rhodes, Rathbun K.
• Granted Patent: US 7,792,562 B2
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• 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: C12Q 1/006 for glucose

Abstract

Devices and methods for determining analyte levels are described. The devices and methods allow for the implantation of analyte-monitoring devices, such as glucose monitoring devices, that result in the delivery of a dependable flow of blood to deliver sample to the implanted device. The devices comprise a unique microarchitectural arrangement in the sensor region that allows accurate data to be obtained over long periods of time.

Claims

1. A device for measuring a glucose concentration in a host, the device comprising:

a sensing mechanism operably connected to an electronic circuit and configured to continuously measure a signal associated with a glucose concentration in a host for a period of time; and

a membrane located over at least a portion of the sensing mechanism, wherein the membrane is configured to control a flux of oxygen and glucose;

wherein the device is capable of exhibiting, at a glucose concentration of about 400 mg/dL, no more than a 10% drop in sensor output over a range of pO₂ from about 150 mm Hg down to about 30 mm Hg.

2. The device of claim 1, wherein the sensing mechanism comprises a first electrode formed at least in part from a platinum wire.

3. The device of claim 2, wherein the sensing mechanism further comprises a second electrode formed at least in part from a silver wire.

4. The device of claim 3, wherein the membrane is located over the first electrode and the second electrode.

5. The device of claim 1, wherein the membrane comprises an enzyme layer comprising an enzyme.

6. The device of claim 1, wherein the membrane comprises an interference layer.

7. The device of claim 1, wherein the membrane comprises polysulfone.

8. The device of claim 1, wherein the membrane comprises a fluorine-containing polymer.

9. The device of claim 1, wherein the membrane comprises a copolymer comprising at least two monomers selected from the group consisting of a silicone polymer, a polycarbonate, and a polyurethane.

10. The device of claim 1, wherein the membrane comprises a silicone polymer, a polycarbonate, and a polyurethane.

11. The device of claim 1, wherein the membrane comprises a block copolymer.

12. The device of claim 1, wherein the membrane comprises a polycarbonate-polyether.

13. The device of claim 1, wherein the resistance layer is monolithic and homogeneous.

14. The device of claim 1, wherein the resistance layer is monolithic and heterogeneous.

15. The device of claim 1, wherein at least 95% of glucose concentration values measured by the signal are within 25% of one or more reference values over a useful life of the device, and wherein the one or more reference values are determined by analysis of blood.

16. The device of claim 1, wherein the device is configured to respond substantially linearly to changes in glucose concentration at a glucose concentration of up to about 500 mg/dL or more.

17. The device of claim 1, wherein the membrane has a thickness of from about 15 microns to about 60 microns.

18. The device of claim 1, wherein the membrane has a thickness of from about 20 microns to about 60 microns.

19. The device of claim 1, wherein the membrane has a thickness of from about 40 microns to about 60 microns.

20. The device of claim 1, wherein the period of time is greater than about 3 days.

21. The device of claim 1, wherein the period of time is greater than about 5 days.

22. The device of claim 1, wherein the period of time is greater than about 7 days.

23. The device of claim 1, wherein an offset current defined by a current at 0 mg/dL remains stable during a period of time of continuous measurement of the glucose concentration in the host.