ENTRAPMENT OF BOTH GLUCOSE-OXIDASE AND PEROXIDASE IN REGENERATED SILKFIBROIN MEMBRANE - CHARACTERIZATION OF THE MEMBRANE-STRUCTURE AND ITSAPPLICATION TO AN AMPEROMETRIC GLUCOSE SENSOR EMPLOYING METHYLENE GREEN AS AN ELECTRON-TRANSFER MEDIATOR

Two enzmyes, glucose oxidase and peroxidase, were for the first time s imultaneously immobilized in regenerated silk fibroin membrane. The st ructure and morphology of the regenerated silk fibroin membrane contai ning both glucose oxidase and peroxidase were investigated with IR spe ctra and SEM. The bienzymes do not change the structures of the regene rated silk fibroin in the membrane, which has an islands-sea structure . For the first time, an amperometric methylene green mediating sensor for glucose based on co-immobilization of both glucose oxidase and pe roxidase in regenerated silk fibroin was constructed. Cyclic voltammet ry and amperometry were used to test the suitability of methylene gree n shuttling electrons between peroxidase and the glassy carbon electro de. The bienzyme-based system offers fast response and high sensitivit y of the sensor to glucose. The effects of pH, temperature, and the co ncentration of the mediator on the response current were evaluated, an d the dependence of the Michaelis-Menten constant K-m(app) on the conc entration of the mediator was investigated.