Polymer membranes for continuous analyte sensors

• US 8,682,408 B2
• Filed: 03/05/2010
• Issued: 03/25/2014
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Boock, Robert, Rixman, Monica A., Zhang, Huashi, Estes, Michael J., Lawrence, Kristina
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US12/718,332
• Publication Number:
  US 20100274107A1
• Time in Patent Office: 1,481 Days
• Field of Search: 600/309, 600345-366
• US Class Current: 600/345
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• 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 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• 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: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/40 Semi-permeable membranes or partitions

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

an implantable sensor configured to continuously measure in vivo a signal associated with an analyte concentration in a host; and

a membrane located over the sensor;

wherein the device is configured to provide, at analyte concentrations of from 40 mg/dL to 80 mg/dL, a level of accuracy corresponding to a mean absolute relative difference of no more than 10% over a sensor session of at least 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

2. The device of claim 1, wherein the membrane comprises an enzyme configured to react with the analyte.

3. The device of claim 1, wherein the membrane comprises a copolymer and a hydrophilic portion.

4. The device of claim 1, wherein the copolymer comprises a polyurethane.

5. The device of claim 4, wherein the copolymer further comprises a silicone segment.

6. The device of claim 5, wherein the copolymer further comprises a polycarbonate segment.

7. The device of claim 1, wherein the device is configured to provide, at analyte concentrations of from 40 mg/dL to 400 mg/dL, a level of accuracy of a mean absolute relative difference of no more than 10% over the sensor session, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

8. The device of claim 7, wherein the mean absolute relative difference corresponding to measurements at analyte concentrations of from 40 mg/dL to 80 mg/dL is from 6% to 10%.

9. The device of claim 1, wherein the mean absolute relative difference corresponding to measurements at analyte concentrations of from 40 mg/dL to 80 mg/dL is from 4.9% to 10%.

10. The device of claim 1, wherein the membrane comprises a material that is a polymer produced by a reaction of an isocyanate.

11. The device of claim 10, wherein the isocyanate is a polyisocyanate.

12. The device of claim 11, wherein the polyisocyanate is a diisocyanate.

13. The device of claim 1, wherein the sensor comprises an electrode configured to oxidize a measured species that is a product of an enzyme-catalyzed reaction with the analyte, whereby the signal is generated.

14. A system for continuous measurement of an analyte concentration, the system comprising:

an implantable sensor comprising a sensing region configured to continuously produce in vivo sensor data associated with an analyte concentration in a host, wherein the sensor further comprises a membrane located over the sensing region;

a processor configured to process continuous sensor data; and

a user interface configured to display information associated with continuous sensor data;

wherein the sensor is configured to provide, at analyte concentrations of from 40 mg/dL and 400 mg/dL, a level of accuracy of a mean absolute relative difference of no more than 10% over a sensor session of at least 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

15. The system of claim 14, wherein the membrane comprises an enzyme configured to react with the analyte.

16. The device of claim 14, wherein the membrane comprises a copolymer and a hydrophilic portion.

17. The device of claim 14, wherein the copolymer comprises a polyurethane.

18. The device of claim 17, wherein the copolymer further comprises a silicone segment.

19. The device of claim 18, wherein the copolymer further comprises a polycarbonate segment.

20. The system of claim 14, wherein the sensor is configured to provide, at analyte concentrations of from 40 mg/dL to 80 mg/dL, a level of accuracy of a mean absolute relative difference of no more than 10% over a sensor session of at least 3 days, wherein one or more reference measurements associated with calculation of the mean absolute relative difference are determined by analysis of blood.

21. The system of claim 20, wherein the mean absolute relative difference corresponding to measurements at analyte concentrations of from 40 mg/dL to 80 mg/dL is from 6% to 10%.

22. The system of claim 14, wherein the mean absolute relative difference corresponding to measurements at analyte concentrations of from 40 mg/dL to 400 mg/dL is from 6.8% to 10%.

23. The system of claim 14, wherein the membrane comprises a material that is a polymer produced by a reaction of an isocyanate.

24. The system of claim 23, wherein the isocyanate is a polyisocyanate.

25. The system of claim 24, wherein the polyisocyanate is a diisocyanate.

26. The system of claim 14, wherein the sensor comprises an electrode configured to oxidize a measured species that is a product of an enzyme-catalyzed reaction with the analyte, whereby the signal is generated.

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

an implantable sensor configured to continuously measure in vivo a signal associated with an analyte concentration in a host; and

a membrane located over the sensor;

wherein, over a sensor session of at least 3 days, the device is configured to;

provide a level of accuracy corresponding to a first mean absolute relative difference value at analyte concentrations of from 40 mg/dL to 80 mg/dL, wherein one or more reference measurements associated with calculation of the first mean absolute relative difference are determined by analysis of blood; and

provide a level of accuracy corresponding to a second mean absolute relative difference value at analyte concentrations of from 40 mg/dL to 400 mg/dL, wherein one or more reference measurements associated with calculation of the second mean absolute relative difference are determined by analysis of blood; and

wherein the first mean absolute relative difference value is less than or equal to the second mean absolute relative difference value.

28. The device of claim 27, wherein the membrane comprises an enzyme configured to react with the analyte.

29. The device of claim 27, wherein the membrane comprises a copolymer and a hydrophilic portion.

30. The device of claim 27, wherein the copolymer comprises a polyurethane.

31. The device of claim 30, wherein the copolymer further comprises a silicone segment.

32. The device of claim 31, wherein the copolymer further comprises a polycarbonate segment.

33. The device of claim 27, wherein the first mean absolute relative difference value is from 4.9% to 10%.

34. The device of claim 27, wherein the membrane comprises a material that is a polymer produced by a reaction of an isocyanate.

35. The device of claim 34, wherein the isocyanate is a polyisocyanate.

36. The device of claim 35, wherein the polyisocyanate is a diisocyanate.

37. The device of claim 27, wherein the sensor comprises an electrode configured to oxidize a measured species that is a product of an enzyme-catalyzed reaction with the analyte, whereby the signal is generated.

38. A system for continuous measurement of an analyte concentration, the system comprising:

an implantable sensor configured to continuously measure in vivo a signal associated with an analyte concentration in a host, wherein the sensor further comprises a membrane located over the sensor;

a processor configured to process continuous sensor data; and

a user interface configured to display information associated with continuous sensor data;

wherein, over a sensor session of at least 3 days, the system is configured to;

provide a level of accuracy corresponding to a first mean absolute relative difference value at analyte concentrations of from 40 mg/dL to 80 mg/dL, wherein one or more reference measurements associated with calculation of the first mean absolute relative difference are determined by analysis of blood; and

provide a level of accuracy corresponding to a second mean absolute relative difference value at analyte concentrations of from 40 mg/dL to 400 mg/dL, wherein one or more reference measurements associated with calculation of the second mean absolute relative difference are determined by analysis of blood; and

wherein the first mean absolute relative difference value is less than or equal to the second mean absolute relative difference value.

39. The system of claim 38, wherein the membrane comprises an enzyme configured to react with the analyte.

40. The device of claim 38, wherein the membrane comprises a copolymer and a hydrophilic portion.

41. The device of claim 38, wherein the copolymer comprises.

42. The device of claim 41, wherein the copolymer further comprises a silicone segment.

43. The device of claim 42, wherein the copolymer further comprises a polycarbonate segment.

44. The system of claim 38, wherein the first mean absolute relative difference value is from 4.9% to 10%.

45. The system of claim 38, wherein the membrane comprises a material that is a polymer produced by a reaction of an isocyanate.

46. The system of claim 45, wherein the isocyanate is a polyisocyanate.

47. The system of claim 46, wherein the polyisocyanate is a diisocyanate.

48. The system of claim 38, wherein the sensor comprises an electrode configured to oxidize a measured species that is a product of an enzyme-catalyzed reaction with the analyte, whereby the signal is generated.