System and method for analyte sampling and analysis with hydrogel

• US 8,224,414 B2
• Filed: 09/13/2005
• Issued: 07/17/2012
• Est. Priority Date: 10/28/2004
• Status: Expired due to Fees

• Current Assignee: Echo Therapeutics Incorporated
• Original Assignee: Echo Therapeutics Incorporated
• Inventors: Kellogg, Scott C., Chuang, Han
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): JANG, CHRISTIAN YONGKYUN
• Application Number:
  US11/223,971
• Publication Number:
  US 20060094946A1
• Time in Patent Office: 2,499 Days
• Field of Search: 600/345, 600/347, 600/365, 435/14, 205/777.5, 205/778
• 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 sensor assembly for a transdermal analyte monitoring system comprising:

a polyethylene glycol diacrylate macromer based hydrogel adapted to interface with permeabilized skin of a subject and to receive an analyte through the skin, wherein the polyethylene glycol diacrylate macromer has a molecular weight of 2000 to 8000 Da and is cross-linked in the presence of an enzyme to form a network of cross-linked macromer that entraps at least a portion of the enzyme;

an electrode assembly comprising at least a first and second electrode, the first and second electrodes being arranged adjacent to each other on a surface of the a sensor body and positioned adjacent the hydrogel;

wherein during operation the sensor assembly is positioned adjacent a permeabilized skin of the subject such that the enzyme reacts continuously with the analyte received through the subject'"'"'s skin and

an electrical signal which correlates to an analyte value is detected by the electrode assembly.

2. The sensor assembly claim 1, wherein the analyte value is the flux of the analyte through the subject'"'"'s skin.

3. The sensor assembly of claim 1, wherein the analyte value is the concentration of the analyte in the subject'"'"'s body fluid.

4. The sensor assembly of claim 1, wherein the analyte comprises glucose.

5. The sensor assembly of claim 4, wherein the enzyme is glucose oxidase.

6. The sensor assembly of claim 1, wherein the hydrogel comprises 1-10% glucose oxidase.

7. The sensor assembly of claim 1, wherein the polyethylene glycol diacrylate macromer has a molecular weight of about 3,400 Da.

8. The sensor assembly of claim 1, wherein the hydrogel has a thickness of about 200 micrometers.

9. The sensor assembly of claim 1, wherein the polyethylene glycol diacrylate macromer is a polyethylene glycol diacrylate-n-vinyl pyrrolidone macromer.