RENEWABLE, REAGENTLESS GLUCOSE SENSOR-BASED ON A REDOX MODIFIED ENZYME AND CARBON-SILICA COMPOSITE

A new type of sol-gel derived, ferrocene derivatized glucose oxidase b ased amperometric biosensor is introduced. The electrode consists of g raphite powder impregnated with a ferrocene modified enzyme imbedded i n an organically modified silicate network. In this assembly, graphite powder provides percolation conductivity, the organic modification of the silicate ensures that the whole bulk of the material is not wette d by the analyte, thus providing a thin reactive layer. The ferrocene which is covalently attached to the enzyme acts as a mediator for the enzymatic reaction, thereby communicating with the conducting graphite in the matrix. The electrode can be reproducibly renewed by mechanica l polishing. Thick film biosensors, where a drop of the analyte is suf ficient for the sensing process is also demonstrated with this materia l.