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

• Methylene blue was intercalated into KLaNb2O7 through ion-exchange for the first time.
• Methylene blue forms an inclined monolayer in the layer spaces of the host niobate.
• The MB+–LaNb2O7/GOD/CTS/GCE biosensor possessed excellent activities in detection of glucose.

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 2.5×10−5 M to 2.83×10−3 M and a detection limit of 2.0×10−5 M.

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