Immobilization of horseradish peroxidase onto a composite membrane of regenerated silk fibroin and polyvinyl alcohol and its application to a new methylene blue-mediating sensor for hydrogen peroxide

Abstract Horseradish peroxidase (HRP) was effectively entrapped in a novel composite membrane of polyvinyl alcohol (PVA) and regenerated silk fibroin (RSF). IR and scanning electron microscopy were employed to provide a useful insight into the structure and morphology of the immobilized HRP composite membrane. A new methylene blue-mediating sensor for hydrogen peroxide was constructed which was based on the composite membrane as an immobilization matrix for HRP. Cyclic voltammetry and amperometric measurements were used to demonstrate the efficiency of the new methylene blue mediating an electron transfer between the immobilized HRP and a glassy carbon electrode in bioelectrocatalytic reduction of hydrogen peroxide. Performance and characteristics of the sensor were evaluated with regard to response time, detection limit, selectivity, and dependences on temperature and pH as well as operating and storage stabilities. The sensor has a variety of characteristics including good sensitivity, rapid response time, and low detection limit of 5.0 μ m .