Regenerated silk fibroin membrane as immobilization matrix for peroxidase and fabrication of a sensor for hydrogen peroxide utilizing methylene blue as electron shuttle

Regenerated silk fibroin prepared from waste silk was utilized to immobilize peroxidase. The structures of the composite membranes of regenerated silk fibroin and peroxidase were studied with IR and scanning electron microscopy. It was found that the two kinds of macromolecules are immiscible despite their intermolecular interactions. The major advantage in using water dispersed regenerated silk fibroin was its ability to dissolve the enzyme without any significant loss of enzymatic activity. An amperometric H2O2 biosensor based on methylene blueʹs mediating electron transfer between the immobilized horseradish peroxidase and a glassy carbon electrode was made. Electrocatalytic reduction of H2O2 at the electrode was evaluated with respect to solution pH, temperature, operating potential and concentration of methylene blue. The biosensor exhibited high sensitivity and a short response time of 30 s.