Low oxygen in vivo analyte sensor
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.
1. A glucose sensor system comprising:
an electrode configured to measure a concentration of glucose in a host, wherein the electrode comprises an exposed electroactive surface with an area of from about 0.000084 cm 2 to about 0.016 cm 2 ;
a membrane disposed over the electrode and configured to limit transport of glucose to the electrode; and
sensor electronics operably connected to the electrode and configured to measure a current flow associated with the electrode, wherein the sensor electronics are configured to measure the current flow in at least a picoAmp range;
wherein the system is configured to have a glucose sensitivity of from about 1 pA/mg/dL to about 25 pA/mg/dL, and wherein the system is configured to measure the current flow associated with 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.
2. The glucose sensor system of claim 1 , wherein the sensor electronics are configured to directly measure the current flow associated with the electrode.
3. The glucose sensor system of claim 1 , further comprising an analog-to-digital converter configured to translate the current flow measurement to a digital signal.
4. The glucose sensor system of claim 1 , wherein the membrane comprises a resistance domain configured with a permeability ratio of at least about 50:1 co-analyte to glucose concentration.
5. The glucose sensor system of claim 4 , wherein the permeability ratio is at least about 200:1.
6. The glucose sensor system of claim 1 , wherein the membrane comprises an enzyme.
7. The glucose sensor system of claim 1 , wherein the system is configured to determine a concentration of the glucose in a biological sample via measurement of hydrogen peroxide produced by an enzyme-catalyzed reaction of glucose with oxygen.
8. The glucose sensor system of claim 1 , wherein the system is configured to have an operable life implanted within a host of at least about one week.
9. The glucose sensor system of claim 1 , wherein the system is configured to measure glucose with substantial linearity at an oxygen concentration of less than about 0.3mg/L.
10. The 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.
11. The glucose sensor system of claim 1 , wherein the membrane comprises a polyurethane.
12. A glucose sensor system comprising:
an electrode configured to measure a concentration of glucose in a host;
a membrane disposed over the electrode and configured to limit transport of glucose to the electrode; and
sensor electronics operably connected to the electrode and configured to measure a current flow associated with the electrode;
wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.6 mg/L, and wherein the system is configured to have a glucose sensitivity of from about 1 pA/mg/dL to about 25 pA/mg/dL.
13. The glucose sensor system of claim 12 , wherein the electrode comprises an exposed electroactive surface with an area of from about 0.000084 cm 2 to about 0.016 cm 2 .
14. The glucose sensor system of claim 12 , wherein the membrane comprises a resistance domain configured with a permeability ratio of at least about 50:1 co-analyte to glucose concentration.
15. The glucose sensor system of claim 14 , wherein the permeability ratio is at least about 200:1.
16. The glucose sensor system of claim 12 , wherein the membrane comprises an enzyme.
17. The glucose sensor system of claim 12 , wherein the glucose sensitivity is from about 1 pA/mg/dL to about 10 pA/mg/dL.
18. The glucose sensor system of claim 12 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.15 mg/L.
19. The glucose sensor system of claim 12 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.05 mg/L.
20. The glucose sensor system of claim 12 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.02 mg/L.
21. The glucose sensor system of claim 12 , wherein the sensor electronics are configured to directly measure the current flow associated with the electrode.
22. The glucose sensor system of claim 12 , further comprising an analog-to-digital converter configured to translate the current flow measurement to a digital signal.
23. The glucose sensor system of claim 12 , wherein the system is configured to determine a concentration of glucose in a biological sample via measurement of hydrogen peroxide produced by an enzyme-catalyzed reaction of glucose with oxygen.
24. The glucose sensor system of claim 12 , wherein the system is configured to have an operable life implanted within a host of at least about one week.
25. The glucose sensor system of claim 12 , wherein the system is configured to measure glucose with substantial linearity at an oxygen concentration of less than about 0.3mg/L.
26. The glucose sensor system of claim 12 , wherein the system is configured such that less than about 1 μg of enzyme is consumed over 7 days of continuous operation.
27. The glucose sensor system of claim 12 , wherein the membrane comprises a polyurethane.
28. A glucose sensor system comprising:
an electrode configured to measure a concentration of glucose in a host;
a membrane disposed over the electrode and configured to limit transport of glucose to the electrode; and
sensor electronics operably connected to the electrode and configured to measure a current flow associated with the electrode;
wherein the system is configured to have a glucose sensitivity of from about 1 pA/mg/dL to about 100 pA/mg/dL, and wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.3 mg/L.
29. The glucose sensor system of claim 28 , wherein the electrode comprises an exposed electroactive surface with an area of from about 0.000084 cm 2 to about 0.016 cm 2 .
30. The glucose sensor system of claim 28 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.15 mg/L.
31. The glucose sensor system of claim 28 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.05 mg/L.
32. The glucose sensor system of claim 28 , wherein the system is configured to accurately measure glucose concentrations of up to about 400 mg/dL in a fluid with an oxygen concentration of less than about 0.02 mg/L.
33. The glucose sensor system of claim 28 , wherein the sensor electronics are configured to directly measure the current flow associated with the electrode.
34. The glucose sensor system of claim 28 , further comprising an analog-to-digital converter configured to translate the current flow measurement to a digital signal.
35. The glucose sensor system of claim 28 , wherein the membrane comprises a resistance domain configured with a permeability ratio of at least about 50:1 co-analyte to glucose concentration.
36. The glucose sensor system of claim 35 , wherein the permeability ratio is at least about 200:1.
37. The glucose sensor system of claim 28 , wherein the membrane comprises an enzyme.
38. The glucose sensor system of claim 28 , wherein the system is configured to determine a concentration of glucose in a biological sample via measurement of hydrogen peroxide produced by an enzyme-catalyzed reaction of glucose with oxygen.
39. The glucose sensor system of claim 28 , wherein the system is configured to have an operable life implanted within a host of at least about one week.
40. The glucose sensor system of claim 28 , wherein the system is configured such that less than about 1 μg of enzyme is consumed over 7 days of continuous operation.
41. The glucose sensor system of claim 28 , wherein the membrane comprises a polyurethane.