Biosensor sensitive to hydrogen peroxide via methylene blue incorporated into nafion film as an electron transfer mediator

Biosensor sensitive to hydrogen peroxide was made via methylene blue in Nafion gel as an electron transfer mediator. Cyclic voltommetry and chronoamperometry were for the first time used to illustrate the suitability of electrical communication between immobilized horseradish peroxidase and a glassy carbon electrode via methylene blue incorporated into a (Nafion) perfluorosulfonic acid cation-exchange polymer film. The methylene blue mediator was strongly reatined inside Nafion film through hydrophobic interactions. Effects of applied potential, ionic strength, temperature and pH on the biosensor were investigated. The biosensor possessed a variety of advantages including high sensitivity, long-term stability and rapid response to hydrogen peroxide with a detection limit of 0.1 µmol/L. The high sensitivity of the biosensor was due to the high efficiency of electron transfer between immobilized horseradish peroxidase and the electrode via methylene blue.