A Composite Clay Glucose Biosensor Based on an Electrically Connected HRP

A novel bienzyme electrode based on a redox clay matrix is described for the cathodic detection of glucose. Peroxidase (HRP) was immobilized in clay matrix containing graphite particles. In order to electrically connect the immobilized HRP, electropolymerized films of 3,4-dihydroxybenzaldehyde were generated within the composite matrix. The resulting biosensors were applied to the amperometric detection of H2O2 via its electroenzymatic reduction at 0V (vs. SCE). The influence of the biosensor composition on the efficiency of H2O2 detection was investigated, the highest sensitivity being 130 mAM–1cm–2. The additional immobilization of glucose oxidase in an external clay gel led to a bienzyme electrode for the determination of glucose; the highest sensitivity being 14.95 mAM–1cm–2.