An ultrathin composite membrane has been developed as the outer covering barrierin a model amperometric glucose oxidase enzyme electrode. The membrane wasformed by cathodic electropolymerization of divinylbenzene/ethylvinylbenzene atthe surface of a gold coated polyester support membrane. Permeabilitycoefficients were determined for O2 and glucose across membranes with a range ofpolymer thicknesses. Anionic interferents (such as ascorbate), were screenedfrom the working electrode via a charge exclusion mechanism. The enzymeelectrode showed an initial 10% signal drift when first exposed to whole humanblood over a period of 2 hours, after which responses remained essentiallystable. Whole blood patient glucose determinations yielded a correlationcoefficient of r2=0.99 compared to standard hospital analyses.
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