System and method for analyte sampling and analysis

• US 20060094945A1
• Filed: 09/13/2005
• Published: 05/04/2006
• Est. Priority Date: 10/28/2004
• Status: Abandoned Application

• Current Assignee: Sontra Medical Corporation (Echo Therapeutics Incorporated)
• Original Assignee: Sontra Medical Corporation (Echo Therapeutics Incorporated)
• Inventors: Chuang, Han, Barman, Shikha P.
• Application Number:
  US11/223,960
• Publication Number:
  US 20060094945A1
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/14514 using means for aiding extraction of interstitial fluid, e.g. microneedles or suction
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: A61L 31/145 Hydrogels or hydrocolloids
• CPC Class Codes: C08L 2203/02 for biomedical use
• CPC Class Codes: C08L 33/24 Homopolymers or copolymers of amides or imides
• CPC Class Codes: C08L 33/26 Homopolymers or copolymers of acrylamide or methacrylamide
• CPC Class Codes: G01N 27/3273 Devices therefor, e.g. test element readers, circuitry details not specific to biochemical electrodes G01N33/4875
• CPC Class Codes: G01N 27/4166 measuring a particular property of an electrolyte
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

The invention relates to a transdermal analyte monitoring system comprising a medium adapted to interface with a biological membrane and to receive an analyte from the biological membrane and an electrode assembly comprising a plurality of electrodes, wherein the medium is adapted to react continuously with the analyte, an electrical signal is detected by the electrode assembly, and the electrical signal correlates to an analyte value. The analyte value may be the flux of the analyte through the biological membrane or the concentration of the analyte in a body fluid of a subject. The medium may comprise a vinyl acetate based hydrogel, an agarose based hydrogel, or a polyethylene glycol diacrylate (PEG-DA) based hydrogel, for example. The surface region of the electrode may comprise pure platinum. The system may include an interference filter located between the biological membrane and the electrode assembly for reducing interference in the system. The system may comprise a processor programmed to implement an error correction method that corrects for sensor drift.

Claims

1. A transdermal analyte monitoring system comprising:

a medium adapted to interface with a biological membrane and to receive an analyte from the biological membrane; and

an electrode assembly comprising a plurality of electrodes, wherein a surface region of at least one of the electrode consists essentially of pure platinum;

wherein the medium is adapted to react continuously with the analyte; and

wherein an electrical signal is detected by the electrode assembly, and the electrical signal correlates to an analyte value.

2. The transdermal analyte monitoring system of claim 1, wherein the analyte value is the flux of the analyte through the biological membrane.

3. The transdermal analyte monitoring system of claim 1, wherein the analyte value is the concentration of the analyte in a body fluid of a subject.

4. The transdermal analyte monitoring system of claim 1, further comprising a sensor body that supports the electrode assembly and the medium.

5. The transdermal analyte monitoring system of claim 1, wherein the analyte comprises glucose.

6. The transdermal analyte monitoring system of claim 5, wherein the medium comprises a hydrogel.

7. The transdermal analyte monitoring system of claim 6, wherein the medium further comprises glucose oxidase.

8. The transdermal analyte monitoring system of claim 5, wherein the surface region consisting essentially of pure platinum provides an increased signal representative of glucose concentration as compared with a signal from a surface region comprising platinized carbon.

9. The transdermal analyte monitoring system of claim 5, wherein the surface region consisting essentially of pure platinum provides an increased signal representative of a rate of production of hydrogen peroxide as compared with a signal from a surface region comprising platinized carbon.

10. The transdermal analyte monitoring system of claim 1, further comprising an interference filter located between the biological membrane and the electrode for reducing interference in the transdermal analyte monitoring system.

11. The transdermal analyte monitoring system of claim 10, wherein the interference filter comprises a biocompatible anionic fluoropolymer.

12. The transdermal analyte monitoring system of claim 1, wherein the biological membrane comprises skin.

13. The transdermal analyte monitoring system of claim 1, wherein the electrode assembly comprises a working electrode, a counter electrode, and a reference electrode.

14. A transdermal analyte monitoring system comprising:

a medium adapted to interface with a biological membrane and to receive an analyte from the biological membrane;

an electrode assembly; and

an interference filter located between the biological membrane and the electrode assembly for reducing interference from non-target biological moieties in the transdermal analyte monitoring system.

15. The transdermal analyte monitoring system of claim 14, wherein the medium is adapted to react continuously with the analyte, an electrical signal is detected by the electrode assembly, and the electrical signal correlates to an analyte value.

16. The transdermal analyte monitoring system of claim 14, wherein the interference filter comprises a biocompatible anionic fluoropolymer.

17. The transdermal analyte monitoring system of claim 14, wherein the interference filter comprises Nafion.

18. The transdermal analyte monitoring system of claim 14, wherein the interference filter is selected from the group consisting of:

(3-mercaptopropyl)trimethylsilane, cellulose acetate, 1,8-diaminonapthaline, phenylenediamine, PTFE, a hydrophobic membrane, Nylon and a hydrophylic membrane.

19. The transdermal analyte monitoring system of claim 14, wherein the interference filter located between the electrode assembly and the medium.

20. The transdermal analyte monitoring system of claim 14, where the interference filter is disposed on a surface of an electrode in the electrode assembly.

21. The transdermal analyte monitoring system of claim 14, where the interference filter is disposed on an outer surface of the electrode assembly that contacts the biological membrane in operation.

22. The transdermal analyte monitoring system of claim 15, wherein the analyte value is the flux of the analyte through the biological membrane.

23. The transdermal analyte monitoring system of claim 15, wherein the analyte value is the concentration of the analyte in a body fluid of a subject.

24. The transdermal analyte monitoring system of claim 14, wherein the analyte comprises glucose.

25. The transdermal analyte monitoring system of claim 24, wherein the medium comprises a hydrogel and glucose oxidase.

26. The transdermal analyte monitoring system of claim 14, wherein the interference filter reduces interference effects from unwanted electrochemical oxidation.

27. The transdermal analyte monitoring system of claim 14, wherein the interference filter reduces an anodic signal produced by electrochemical oxidation of ascorbic acid, uric acide, or acetaminophen.

28. The transdermal analyte monitoring system of claim 14, wherein the interference filter reduces biofouling.

29. A method for monitoring an analyte comprising:

positioning a medium with respect to a biological membrane such that the medium can receive an analyte from the biological membrane, wherein an electrode assembly is coupled to the medium, the electrode assembly comprises a plurality of electrodes, and at least one of the electrodes comprises a surface region consisting essentially of pure platinum;

continuously reacting the analyte with the medium; and

detecting an electrical signal with the electrode assembly, wherein the electrical signal correlates to an analyte value.

30. The method of claim 29, further comprising pretreating the biological membrane to increase a permeability of the biological membrane.

31. The method of claim 30, wherein the pretreating step comprises applying low frequency ultrasound to the biological membrane.

32. The method of claim 29, wherein the surface region consisting essentially of pure platinum provides an increased signal representative of glucose concentration as compared with a signal from a surface region comprising platinized carbon.

33. The method of claim 29, wherein the surface region consisting essentially of pure platinum provides an increased signal representative of a rate of production of hydrogen peroxide as compared with a signal from a surface region comprising platinized carbon.

34. A method for monitoring an analyte comprising:

positioning a medium with respect to a biological membrane such that the medium can receive an analyte from the biological membrane, wherein an electrode assembly is coupled to the medium and an interference filter is positioned between an electrode in the electrode assembly and the biological membrane;

continuously reacting the analyte with the medium; and

detecting an electrical signal with the electrode assembly, wherein the electrical signal correlates to an analyte value.

35. The method of claim 34, further comprising pretreating the biological membrane to increase a permeability of the biological membrane.

36. The method of claim 35, wherein the pretreating step comprises applying low frequency ultrasound to the biological membrane.

37. The method of claim 34, wherein the interference filter comprises Nafion.

38. The method of claim 34, wherein the interference filter is selected from the group consisting of:

(3-mercaptopropyl)trimethylsilane, cellulose acetate, 1,8-diaminonapthaline, phenylenediamine, PTFE, a hydrophobic membrane, Nylon and a hydrophylic membrane.

39. The method of claim 34, wherein the interference filter reduces interference effects from unwanted electrochemical oxidation.

40. The method of claim 34, wherein the interference filter reduces an anodic signal produced by electrochemical oxidation of ascorbic acid, uric acide, or acetaminophen.

41. The method of claim 34, wherein the interference filter reduces biofouling.