A novel glucose biosensor constructed by glucose oxidase immobilized with methylene blue intercalated layered lanthanum niobic acid nanocomposite

Abstract

Cationic methylene blue (MB) was intercalated into layered semiconductor KLaNb2O7 for the first time by the ion-exchange method. MB+ forms an inclined monolayer between LaNb2O7− nanosheets and the nanocomposite exhibited a pair of characteristic redox peaks of MB+ cation. The nanocomposite was proved to be capable of immobilizing glucose oxidase (GOD) and facilitate catalytic activities of GOD. The MB+–LaNb2O7/GOD/CTS/GCE biosensor we constructed showed high electrochemical catalytic activities towards oxidation of glucose with the existence of oxygen. The biosensor had a linear range on detection of glucose from 2.5×10−5M to 2.83×10−3M and a detection limit of 2.0×10−5M.