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 muA 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. (C) 2004 Elsevier B.V. All rights reserved.