Development of an amperometric biosensor based on glucose oxidase immobilized through silica sol–gel film onto Prussian Blue modified electrode

A new approach is described that provides the immobilization of glucose oxidase (GOD) on a Prussian Blue (PB)-modified glassy carbon electrode with a silica sol–gel outer layer. A ‘sandwich’ configuration has been employed in the glucose biosensor. The sensor exhibits high sensitivity and selectivity, which due to both electroreduction of PB-modified electrode for H2O2 at lower potential and sol–gel microenviroment. The sol–gel film outside the enzyme layer contributes to both intensified stability and permselectivity. The resulting biosensor is highly sensitive to glucose with a linear calibration plot in the concentration range of 0–4.75 mM glucose, slope 1.182 μA mM−1 l and the detection limit 0.02 mM glucose (S/N=3). It is performed with excellent reproducibility and long-storage stability. It is attempted being used for clinical assay of diabetic patients blood glucose.