POLYMER MEMBRANES FOR CONTINUOUS ANALYTE SENSORS

• US 20090247855A1
• Filed: 03/27/2009
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Abandoned Application

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Boock, Robert, Rixman, Monica A., Zhang, Huashi, Estes, Michael J., Lawrence, Kristina
• Application Number:
  US12/413,166
• Publication Number:
  US 20090247855A1
• 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 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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: C12Q 1/002 Electrode membranes
• CPC Class Codes: C12Q 1/006 for glucose

Abstract

Devices and methods are described for providing continuous measurement of an analyte concentration. In some embodiments, the device has a sensing mechanism and a sensing membrane that includes at least one surface-active group-containing polymer and that is located over the sensing mechanism. The sensing membrane may have a bioprotective layer configured to substantially block the effect and/or influence of non-constant noise-causing species.

Claims

1. A sensor for continuous measurement of an analyte concentration, the sensor comprising:

an electrode and a membrane located over the electrode, the membrane comprising;

a first domain comprising a polymer having a surface active group, the first domain configured to control a flux of an analyte therethrough and to substantially reduce or block a flux of an endogenous interferent therethrough; and

a second domain comprising an enzyme.

2. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 50 to 1.

3. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 100 to 1.

4. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 125 to 1.

5. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 150 to 1.

6. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 200 to 1.

7. The sensor of claim 1, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 300 to 1.

8. The sensor of claim 1, wherein the first domain is configured to substantially reduce or block a flux of an exogenous interferent therethrough.

9. The sensor of claim 8, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 60.

10. The sensor of claim 8, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 30.

11. The sensor of claim 8, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 15.

12. The sensor of claim 1, wherein the polymer comprises a blend of a base polymer and a hydrophilic polymer.

13. The sensor of claim 12, wherein the base polymer is a polyurethane selected from the group consisting of polyether-urethane-urea, polycarbonate-urethane, polyether-urethane, silicone-polyether-urethane, silicone-polycarbonate-urethane, and polyester-urethane.

14. The sensor of claim 12, wherein the hydrophilic polymer is a polymer selected from the group consisting of polyvinyl acetate, poly(ethylene glycol), polyacrylamide, acetates, polyethylene oxide, poly ethyl acrylate, and polyvinylpyrrolidone.

15. The sensor of claim 1, wherein the first domain has a thickness of from about 0.1 microns to about 15 microns.

16. The sensor of claim 1, wherein the second domain has a thickness of from about 0.1 microns to about 10 microns.

17. The sensor of claim 1, wherein the membrane further comprises a third domain configured to substantially reduce or block a flux of an exogenous interferent therethrough.

18. The sensor of claim 17, wherein the third domain has a thickness of from about 0.01 microns to about 5 microns.

19. The sensor of claim 1, wherein the membrane is capable of providing a positive correlation between a sensitivity of in vivo glucose concentration measurements and a sensitivity of in vitro glucose concentration measurements.

20. The sensor of claim 19, wherein the correlation is greater than about 0.8.

21. The device of claim 1, wherein the membrane is capable of providing a ratio between in vivo and in vitro glucose sensitivities of about 1 to 1.

22. The sensor of claim 1, wherein an equivalent peak glucose response to a therapeutic dose of the exogenous interferent administered to a host is less than 100 mg/dL.

23. The sensor of claim 1, wherein the sensor is capable of obtaining a glucose-signal-to-baseline-signal ratio of greater than about 5 to 1.

24. A device for continuously detecting glucose in a host, the device comprising:

a first working electrode comprising a first electroactive surface disposed beneath an enzymatic portion of a membrane system and configured to measure a first signal comprising a glucose signal and a baseline signal; and

a second working electrode comprising a second electroactive surface disposed beneath a non-enzymatic portion of the membrane system and configured to measure a second signal comprising the baseline signal, wherein the membrane system further comprises a bioprotective domain located over each of the first working electrode and the second working electrode, and wherein the bioprotective domain is configured to substantially reduce or block a flux of one or more endogenous interferents therethrough.

25. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 50 to 1.

26. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 100 to 1.

27. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 125 to 1.

28. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 150 to 1.

29. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 200 to 1.

30. The device of claim 24, wherein the bioprotective domain has a glucose-to-oxygen permeability ratio greater than about 300 to 1.

31. The device of claim 24, wherein the first domain is configured to substantially reduce or block a flux of an exogenous interferent therethrough.

32. The device of claim 24, wherein the bioprotective domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 60.

33. The device of claim 24, wherein the bioprotective domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 30.

34. The device of claim 24, wherein the bioprotective domain has a glucose-to-exogenous-interferent permeability ratio less than about 1 to 15.

35. The device of claim 24, wherein the bioprotective domain has a thickness of from about 0.1 microns to about 15 microns.

36. The device of claim 24, wherein the membrane system is capable of providing a positive correlation between a sensitivity of in vivo glucose concentration measurements and a sensitivity of in vitro glucose concentration measurements.

37. The device of claim 36, wherein the correlation is greater than about 0.8.

38. The device of claim 24, wherein the membrane system is capable of providing a ratio between in vivo and in vitro glucose sensitivities of about 1 to 1.

39. The device of claim 24, wherein an equivalent peak glucose response to a therapeutic dose of the exogenous interferent administered to a host is less than 100 mg/dL.

40. The device of claim 24, wherein the device is capable of obtaining a glucose-signal-to-baseline-signal ratio of greater than about 5 to 1.

41. A device for continuous measurement of an analyte concentration, the device comprising:

an electrode and a membrane located over the electrode, the membrane comprising;

a first domain comprising a base polymer and a hydrophilic polymer, the first domain configured to control a flux of the analyte therethrough and configured to substantially reduce or block a flux of an exogenous interferent therethrough by promoting hydrogen bonding with the exogenous interferent, wherein an equivalent peak glucose response to a therapeutic dose of the exogenous interferent administered to a host is less than 100 mg/dL.

42. The device of claim 41, wherein the base polymer is a polyurethane selected from the group consisting of:

polyether-urethane-urea, polycarbonate-urethane, polyether-urethane, silicone-polyether-urethane, silicone-polycarbonate-urethane, and polyester-urethane.

43. The device of claim 41, wherein the hydrophilic polymer is a polymer selected from the group consisting of:

polyvinyl acetate, poly(ethylene glycol), polyacrylamide, acetates, polyethylene oxide, poly ethyl acrylate, and polyvinylpyrrolidone.

44. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 50 to 1.

45. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 100 to 1.

46. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 125 to 1.

47. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 150 to 1.

48. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 200 to 1.

49. The device of claim 41, wherein the first domain has a glucose-to-oxygen permeability ratio greater than about 300 to 1.

50. The device of claim 41, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio greater than about 1 to 60.

51. The device of claim 41, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio greater than about 1 to 30.

52. The device of claim 41, wherein the first domain has a glucose-to-exogenous-interferent permeability ratio greater than about 1 to 15.

53. The device of claim 41, wherein the first domain has a thickness between about 0.1 and 15 microns.

54. The device of claim 41, wherein the membrane is capable of providing a positive correlation between a sensitivity of in vivo glucose concentration measurements and a sensitivity of in vitro glucose concentration measurements.

55. The device of claim 54, wherein the correlation is greater than about 0.8.

56. The device of claim 41, wherein the membrane is capable of providing a ratio between in vivo and in vitro glucose sensitivities of about 1 to 1.

57. The device of claim 41, wherein an equivalent peak glucose response to a therapeutic dose of the exogenous interferent administered to a host is less than 100 mg/dL.

58. The device of claim 41, wherein the device is capable of obtaining a glucose-signal-to-baseline-signal ratio of greater than about 5 to 1.