BIOSENSORS WITH OXIDOREDUCTASES AND INTEGRATED COENZYME OR MEDIATOR RECYCLING

Abstract

Most amperometric enzyme electrodes demand integrated coenzymes and/or mediators for the transfer of redox equivalents between protein and transducer. Thefree diffusibility required for this function of the mediators implies simultaneously their leaking from the electrode chamber. Approaches to overcomethis problem, aiming on the construction of compact independent oxidoreductase electrodes are reportedin this contribution. first attempt is based on the covalent binding of oxidoreductases on various conducting supports. Independent from the material and the binding method no direct electron transfer was obtained in any case. A subsequent immobilization of mediators through long spacersis therefore envisaged. In another approach, the functionalization of conducting surfaces with orientated mediators boundthrough conducting spacersis investigated, aiming on the subsequentaffinant binding of coenzymes. The most successful and promising way seemsto bind mediators or coenzymes through spacers to the enzymes themselves and to immobilize these complexes onto or within functionalized electrode surfaces.