System and method for analyte sampling and analysis with hydrogel
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.
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.