Sol-gel derived, ferrocenyl-modified silicate-graphite composite electrode: Wiring of glucose oxidase

A new type of porous, hybrid organic-inorganic material is synthesized and used for direct wiring of active enzymes. The material witnesses a dispersion of graphite powder and redox enzyme incorporated in a multi-functional, ferrocene-, amine- and methyl-modified silicate backbone. Each species in this integrated construction accomplishes a specialized task: 1. (a) the graphite provides conductivity by percolation; 2. (b) the silicate provides the highly crosslinked, rigid backbone which is used to cage the redox enzyme; 3. (c) ferrocene functional groups are responsible for the signal transduction from the active center of the enzyme to the electron conductive surface; 4. (d) amine groups are incorporated for their high affinity for excess negative charges on the surface of glucose oxidase. Also, the combination of methyl and amine groups is advantageous to maintain control over the wetted electroactive section of the electrode. Amperometric sensing of glucose demonstrates the application of this new material.