Dual electrode system for a continuous analyte sensor

• US 7,467,003 B2
• Filed: 10/04/2006
• Issued: 12/16/2008
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brister, Mark, Petisce, James R., Simpson, Peter
• Primary Examiner(s): Nasser; Robert L
• Application Number:
  US11/543,539
• Publication Number:
  US 20070027384A1
• Time in Patent Office: 804 Days
• Field of Search: None
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• 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: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

Disclosed herein are systems and methods for a continuous analyte sensor, such as a continuous glucose sensor. One such system utilizes first and second working electrodes to measure additional analyte or non-analyte related signal. Such measurements may provide a background and/or sensitivity measurement(s) for use in processing sensor data and may be used to trigger events such as digital filtering of data or suspending display of data.

Claims

1. An analyte sensor configured for insertion into a host for measuring an analyte in the host, the sensor comprising:

a first working electrode disposed beneath an active enzymatic portion of a membrane;

a second working electrode disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane; and

a non-conductive material located between the first working electrode and the second working electrode, wherein the first working electrode and the second working electrode are intertwined.

2. The sensor of claim 1, further comprising a reference electrode, wherein the reference electrode is configured to provide electrical conductance and structural support.

3. The sensor of claim 1, further comprising a reference electrode, wherein the reference electrode is configured to provide electrical conductance and a diffusion barrier.

4. The sensor of claim 1, further comprising at least one of a reference electrode and a counter electrode.

5. The sensor of claim 4, wherein the at least one of the reference electrode and the counter electrode, together with the first working electrode and the second working electrode, integrally forms at least a portion of the sensor.

6. The sensor of claim 4, wherein the at least one of the reference electrode and the counter electrode is located at a position remote from the first working electrode and the second working electrode.

7. The sensor of claim 4, wherein a surface area of at least one of the reference electrode and the counter electrode is at least six times a surface area of at least one of the first working electrode and the second working electrode.

8. The sensor of claim 1, wherein each of the first working electrode and the second working electrode comprises a wire with a diameter from about 0.001 inches to about 0.010 inches.

9. The sensor of claim 1, wherein each of the first working electrode and the second working electrode comprises a bulk material or plated wire.

10. The sensor of claim 1, wherein the non-conductive material is conformally coated around a circumference of a substantial portion of at least one of the first working electrode and the second working electrode.

11. The sensor of claim 1, wherein the non-conductive material comprises an insulating material selected from the group consisting of:

parylene, fluorinated polymers, polyethyleneterephthalate, PTFE, ETFE, polyurethane, polyethylene, polyimide, and silicone.

12. The sensor of claim 1, wherein the sensor comprises a width of no more than about 0.015 inches.

13. The sensor of claim 1, wherein the first and second working electrodes are at least one of bundled, coiled and twisted.

14. The sensor of claim 13, further comprising a non-conductive material surrounding at least a portion of the first and second working electrodes.

15. The sensor of claim 1, wherein, wherein the non-conductive material is configured to provide an insulative property and structural support.

16. The sensor of claim 1, wherein the membrane comprises an interference domain located over the first and second working electrodes.

17. A glucose sensor configured for insertion into a host for measuring a glucose concentration in the host, the sensor comprising:

a first working electrode configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential;

a second working electrode configured to generate a second signal associated with non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential, wherein the first and second working electrodes are at least one of bundled and twisted; and

a non-conductive material located between the first working electrode and the second working electrode.

18. The sensor of claim 17, wherein the sensor is configured for implantation into the host.

19. The sensor of claim 18, wherein the sensor is configured for subcutaneous implantation in a tissue of the host.

20. The sensor of claim 18, wherein the sensor is configured for indwelling in a blood stream of the host.

21. The sensor of claim 17, wherein the sensor substantially continuously measures an analyte concentration in the host.

22. The sensor of claim 17, wherein the non-glucose related electroactive species comprises at least one species selected from the group consisting of interfering species, non-reaction-related hydrogen peroxide, and other electroactive species.

23. The sensor of claim 17, further comprising electronics operably connected to the first working electrode and the second working electrode, and configured to provide the first signal and the second signal to generate glucose concentration data substantially without signal contribution due to non-glucose-related noise.

24. The sensor of claim 17, wherein the first working electrode, the second working electrode, and the non-conductive material integrally form at least a portion of the sensor.

25. The sensor of claim 24, wherein the first working electrode and the second working electrode each integrally form a substantial portion of the sensor configured for insertion in the host.

26. The sensor of claim 24, further comprising a reference electrode, wherein the first working electrode, the second working electrode, and the reference electrode each integrally form a substantial portion of the sensor configured for insertion in the host.

27. The sensor of claim 17, wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of an analyte or a co-analyte between the first working electrode and the second working electrode.

28. The sensor of claim 17, wherein each of the first working electrode and the second working electrode are configured to provide electrical conductance and structural support.

29. The sensor of claim 28, further comprising a reference electrode, wherein the reference electrode is configured to provide electrical conductance and structural support.

30. The sensor of claim 17, further comprising a reference electrode, wherein the reference electrode is configured to provide electrical conductance and a diffusion barrier.

31. The sensor of claim 17, further comprising a reference electrode, wherein the reference electrode is configured to provide a diffusion barrier and structural support.

32. The sensor of claim 17, wherein the non-conductive material is configured to provide an insulative property and structural support.

33. The sensor of claim 17, wherein the non-conductive material is configured to provide an insulative property and a diffusion barrier.

34. The sensor of claim 17, wherein the non-conductive material is configured to provide a diffusion barrier and structural support.

35. The sensor of claim 17, wherein each of the first working electrode and the second working electrode comprises a wire with a diameter from about 0.001 inches to about 0.010 inches.

36. The sensor of claim 17, wherein each of the first working electrode and the second working electrode comprises a bulk material or plated wire.

37. The sensor of claim 17, wherein the non-conductive material is formed around a circumference of a substantial portion of at least one of the first working electrode and the second working electrode.

38. The sensor of claim 37, wherein the non-conductive material is conformally coated around a circumference of a substantial portion of at least one of the first working electrode and the second working electrode.

39. The sensor of claim 17, wherein the non-conductive material comprises an insulating material selected from the group consisting of:

parylene, fluorinated polymers, polyethyleneterephthalate, PTFE, ETFE, polyurethane, polyethylene, polyimide, and silicone.

40. The sensor of claim 17, wherein the sensor comprises a width of no more than about 0.015 inches.

41. The sensor of claim 17, wherein the first and second working electrodes are twisted together.

42. The sensor of claim 41, further comprising a non-conductive material surrounding at least a portion of the first and second working electrodes.

43. The sensor of claim 17, wherein each of the first working electrode, the second working electrode, and the non-conductive material are configured provide at least two functions selected from the group consisting of electrical conductance, insulative property, structural support, and diffusion barrier.

44. The sensor of claim 17, further comprising a membrane system located over the first and second working electrodes, wherein the membrane system comprises an interference domain.

45. An analyte sensor configured for insertion into a host for measuring an analyte in the host, the sensor comprising:

a first working electrode comprising a first electroactive surface disposed beneath an active enzymatic portion of a membrane, wherein the first working electrode defines a first longitudinal axis;

a second working electrode comprising a second electroactive surface disposed beneath an inactive-enzymatic or non-enzymatic portion of a membrane, wherein the second working electrode defines a second longitudinal axis that is co-linear with the first longitudinal axis, both of which define a longitudinal axis of the sensor; and

an insulator located between the first electroactive surface and the second electroactive surface, wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first electroactive surface and the second electroactive surface wherein the analyte sensor is configured to indwell in a blood stream of the host, and wherein the diffusion barrier comprises an offset of the first electroactive surface and the second electroactive surface along the longitudinal axis of the sensor that provides a flow path diffusion barrier configured to block or avoid a substantial amount of diffusion of at least one of the analyte and the co-analyte between the first electroactive surface and the second electroactive surface.

46. The sensor of claim 45, wherein the flow path diffusion barrier comprises a location of the first electroactive surface configured to be upstream from the second electroactive surface when inserted into the blood stream.

47. The sensor of claim 45, wherein the flow path diffusion barrier comprises a location of the first electroactive surface configured to be downstream from the second electroactive surface when inserted into the blood stream.

48. The sensor of claim 45, wherein each of the first working electrode and the second working electrode comprises a wire with a diameter from about 0.001 inches to about 0.010 inches.

49. The sensor of claim 45, wherein each of the first working electrode and the second working electrode comprises a bulk material or plated wire.

50. The sensor of claim 45, wherein the non-conductive material is formed around a circumference of a substantial portion of at least one of the first working electrode and the second working electrode.

51. The sensor of claim 50, wherein the non-conductive material is conformally coated around a circumference of a substantial portion of at least one of the first working electrode and the second working electrode.

52. The sensor of claim 45, wherein the non-conductive material comprises an insulating material selected from the group consisting of:

parylene, fluorinated polymers, polyethyleneterephthalate, PTFE, ETFE, polyurethane, polyethylene, polyimide, and silicone.

53. The sensor of claim 45, wherein the sensor comprises a width of no more than about 0.015 inches.

54. The sensor of claim 45, wherein the first and second working electrodes are at least one of bundled, coiled and twisted.

55. The sensor of claim 54, further comprising a non-conductive material surrounding at least a portion of the first and second working electrodes.

56. The sensor of claim 45, wherein the sensor comprises a glucose sensor, and wherein the first working electrode is configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential.

57. The sensor of claim 45, wherein the second working electrode is configured to generate a second signal associated with noise of the glucose sensor, the noise comprising signal contribution due to non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential.

58. The sensor of claim 57, wherein the non-glucose related electroactive species comprises at least one species selected from the group consisting of interfering species, non-reaction-related hydrogen peroxide, and other electroactive species.

59. The sensor of claim 45, further comprising electronics operably connected to the first working electrode and the second working electrode, and configured to provide the first signal and the second signal to generate glucose concentration data substantially without signal contribution due to non-glucose-related noise.

60. The sensor of claim 45, wherein the membrane comprises an interference domain located over the first and second working electrodes.

61. A glucose sensor configured for insertion into a host for measuring a glucose concentration in the host, the sensor comprising:

a first working electrode configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential;

a second working electrode configured to generate a second signal associated with noise of the glucose sensor comprising signal contribution due to non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential, wherein the first and second working electrodes are twisted together along a longitudinal axis defined by longitudinal axes of the first and second electrodes; and

a non-conductive material located between the first working electrode and the second working electrode, wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of the analyte and the co-analyte between the first working electrode and the second working electrode.

62. The sensor of claim 61, wherein the non-conductive material is configured to provide an insulative property and a diffusion barrier.

63. The sensor of claim 61, further comprising a reference electrode, wherein the reference electrode is configured to provide a diffusion barrier and structural support.

64. The sensor of claim 61, wherein the non-conductive material is configured to provide a diffusion barrier and structural support.

65. The sensor of claim 61, wherein the diffusion barrier comprises a physical diffusion barrier configured to physically or spatially block a substantial amount of diffusion of at least one of the analyte and the co-analyte between the first working electrode and the second working electrode.

66. The sensor of claim 61, wherein the diffusion barrier comprises a temporal diffusion barrier configured to block or avoid a substantial amount of diffusion or reaction of at least one of the analyte and the co-analyte between the first working electrode and the second working electrode.

67. The sensor of claim 61, wherein the analyte sensor is configured to indwell in a blood stream of the host, and wherein the diffusion barrier comprises a configuration of the first working electrode and the second working electrode that provides a flow path diffusion barrier configured to block or avoid a substantial amount of diffusion of at least one of the analyte and the co-analyte between the first working electrode and the second working electrode.

68. The sensor of claim 61, further comprising at least one of a reference electrode and a counter electrode.

69. The sensor of claim 61, wherein the sensor is configured for implantation into the host.

70. The sensor of claim 61, wherein the sensor substantially continuously measures an analyte concentration in the host.

71. The sensor of claim 61, further comprising electronics operably connected to the first working electrode and the second working electrode, and configured to provide the first signal and the second signal to generate glucose concentration data substantially without signal contribution due to non-glucose-related noise.

72. The sensor of claim 61, wherein the first working electrode, the second working electrode, and the insulator integrally form a substantial portion of the sensor configured for insertion in the host.

73. The sensor of claim 61, wherein each of the first working electrode, the second working electrode, and the non-conductive material are configured provide at least two functions selected from the group consisting of:

electrical conductance, insulative property, structural support, and diffusion barrier.

76. The sensor of claim 61, further comprising a membrane system located over the first and second working electrodes, wherein the membrane system comprises an interference domain.

74. A glucose sensor configured for insertion into a host for measuring a glucose concentration in the host, the sensor comprising:

a first working electrode configured to generate a first signal associated with glucose and non-glucose related electroactive compounds, the glucose and non-glucose related electroactive compounds having a first oxidation potential; and

a second working electrode configured to generate a second signal associated with non-glucose related electroactive compounds with an oxidation potential that substantially overlaps with the first oxidation potential, wherein the first working electrode and the second working electrode are interdigitated.

75. The sensor of claim 74, wherein the first working electrode and the second working electrode provide electrical conductance for the sensor.

77. The sensor of claim 74, further comprising a reference electrode, wherein the reference electrode provides electrical conductance for the sensor.

78. The sensor of claim 74, further comprising an insulator, wherein the insulator provides electrical insulation for the sensor.

79. The sensor of claim 74, further comprising at least one additional electrode selected from the group consisting of a reference electrode and a counter electrode.

80. The sensor of claim 79, wherein the additional electrode, together with the first working electrode and the second working electrode, integrally form at least a portion of the sensor.

81. The sensor of claim 79, wherein the additional electrode is located at a position remote from the first and second working electrodes.

82. The sensor of claim 79, wherein a surface area of the additional electrode is at least six times a surface area of at least one of the first working electrode and the second working electrode.

83. The sensor of claim 74, wherein the sensor is configured for implantation into the host.

84. The sensor of claim 83, wherein the sensor is configured for subcutaneous implantation in a tissue of a host.

85. The sensor of claim 83, wherein the sensor is configured for indwelling in a blood stream of a host.

86. The sensor of claim 74, wherein the sensor substantially continuously measures an analyte concentration in a host.

87. The sensor of claim 74, further comprising a non-conductive material positioned between the first working electrode and the second working electrode,

88. The sensor of claim 87, wherein each of the first working electrode, the second working electrode, and the non-conductive material are configured to provide at least two functions selected from the group consisting of electrical conductance, insulative property, structural support, and diffusion barrier.

89. The sensor of claim 74, wherein the sensor comprises a diffusion barrier configured to substantially block diffusion of at least one of an analyte and a co-analyte between the first working electrode and the second working electrode.

90. The sensor of claim 74, wherein the first working electrode and second working electrode each comprise bulk metal.

91. The sensor of claim 90, wherein the bulk metal comprises a wire.

92. The sensor of claim 74, further comprising a membrane system located over the first and second working electrodes, wherein the membrane system comprises an interference domain.