Glassy carbon electrode modified with glucose oxidase-graphene-nano-copper composite film for glucose sensing

We report on the modification of a glassy carbon electrode with graphene and Cu nanoparticles (Cu-nano), and how this electrode can serve as a platform for the construction of a novel electrochemical biosensor for the study of the direct electrochemistry of glucose oxidase and then application for glucose detection. To obtain the biosensor, the glucose oxidase was immobilized on the surface of the graphene and Cu-nano modified electrode, and this process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. A sensitive biosensor with a detection limit of 5 mu M glucose was achieved, which was thought to result from a combination of beneficial effects including the biocompatibility and large surface area of the Cu-nano, the high conductivity of the graphene, the synergistic effects of composite film, and the increased quantity of glucose oxidase adsorbed on the electrode surface. The voltammetric responses were proportional to the concentration of glucose in the range from 0.05 mM to 12 mM. The biosensor was sensitive and stable. (C) 2012 Elsevier Ltd. All rights reserved.