초록

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.

대표청구항 ▼

What is claimed is: 1. A continuous glucose sensor system comprising: an implantable body comprising an electrode configured to measure a glucose level in a host; a membrane disposed over the electrode, wherein the membrane comprises a resistance domain configured to limit transport of glucose to t

What is claimed is: 1. A continuous glucose sensor system comprising: an implantable body comprising an electrode configured to measure a glucose level in a host; a membrane disposed over the electrode, wherein the membrane comprises a resistance domain configured to limit transport of glucose to the electrode and an enzyme configured to catalyze a reaction of glucose and oxygen; and sensor electronics operably connected to the electrode and configured to measure a current produced by the electrode with substantial linearity at glucose concentrations of to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.3 mg/L. 2. The continuous glucose sensor system of claim 1, wherein the system is configured such that less than about 1 μg of enzyme is consumed over 7 days of continuous operation. 3. The continuous glucose sensor system of claim 1, wherein the oxygen concentration is less than about 0.15 mg/L. 4. The continuous glucose sensor system of claim 1, wherein the oxygen concentration of is less than about 0.05 mg/L. 5. The continuous glucose sensor system of claim 1, wherein the oxygen concentration of is less than about 0.02 mg/L. 6. The continuous glucose sensor 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. 7. The continuous glucose sensor system of claim 1, wherein the resistance domain is configured to have a permeability ratio of at least about 50:1 of oxygen to glucose. 8. The continuous glucose sensor system of claim 7, wherein the resistance domain is configured to have a permeability ratio of at least about 200:1 of oxygen to glucose. 9. The continuous glucose sensor 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. 10. The continuous glucose sensor system of claim 1, wherein the resistance domain comprises a silicone. 11. The continuous glucose sensor system of claim 1, wherein the resistance domain comprises a fluorocarbon. 12. The continuous glucose sensor system of claim 1, wherein the resistance domain comprises a polyurethane. 13. The continuous glucose sensor system of claim 1, wherein the resistance domain comprises a polyethylene oxide. 14. A continuous glucose sensor system comprising: an implantable body comprising an electrode configured to measure a glucose level in a host; a membrane disposed over the electrode, wherein the membrane comprises a resistance domain configured to limit transport of glucose to the electrode and an enzyme configured to catalyze a reaction of glucose and oxygen; and a sensor electronics unit operably connected to the electrode and configured to measure a current produced by the electrode with substantial linearity at glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.6 mg/L, wherein the system is configured such that less than about 1 μg of enzyme is consumed over 7 days of continuous operation. 15. The continuous glucose sensor system of claim 14, wherein the oxygen concentration is less than about 0.3 mg/L. 16. The continuous glucose sensor system of claim 14, 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. 17. The continuous glucose sensor system of claim 14, wherein the resistance domain is configured to have a permeability ratio of at least about 50:1 of oxygen to glucose. 18. The continuous glucose sensor system of claim 14, 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. 19. The continuous glucose sensor system of claim 14, wherein the resistance domain comprises a silicone. 20. The continuous glucose sensor system of claim 14, wherein the resistance domain comprises a fluorocarbon. 21. The continuous glucose sensor system of claim 14, wherein the resistance domain comprises a polyurethane. 22. The continuous glucose sensor system of claim 14, wherein the resistance domain comprises a polyethylene oxide. 23. A continuous glucose sensor system comprising: an implantable body comprising an electrode configured to measure a glucose level in a host; a membrane disposed over the electrode, wherein the membrane comprises a resistance domain configured to limit transport of glucose to the electrode and an enzyme configured to catalyze a reaction of glucose and oxygen; and a sensor electronics unit operably connected to the electrode and configured to measure a current produced by the electrode with substantial linearity at glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.6 mg/L, 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. 24. The continuous glucose sensor system of claim 23, wherein the system is configured such that less than about 1 μg of enzyme is consumed over 10 days of continuous operation. 25. The continuous glucose sensor system of claim 23, wherein the resistance domain comprises a silicone. 26. The continuous glucose sensor system of claim 23, wherein the resistance domain comprises a fluorocarbon. 27. The continuous glucose sensor system of claim 23, wherein the resistance domain comprises a polyurethane. 28. The continuous glucose sensor system of claim 23, wherein the resistance domain comprises a polyethylene oxide. 29. The continuous glucose sensor system of claim 23, wherein the oxygen concentration is less than about 0.3 mg/L. 30. The continuous glucose sensor system of claim 23, 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. 31. The continuous glucose sensor system of claim 23, wherein the resistance domain is configured to have a permeability ratio of at least about 50:1 of oxygen to glucose.