, Volume 180, Issue 1-2, pp 127-135
Date: 15 Nov 2012

Direct electrodeposition of a biocomposite consisting of reduced graphene oxide, chitosan and glucose oxidase on a glassy carbon electrode for direct sensing of glucose

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Abstract

We have electrodeposited a composite film consisting of graphene oxide, chitosan and glucose oxidase directly on a glassy carbon electrode (GCE) through electrochemical reduction of a solution of the 3 components under controlled direct electrical potential. The procedure takes only several minutes, and the thickness of the resulting film is uniform and controllable. The GOx has uncompromised bioactivity and exhibits reversible 2-proton and 2-electron transfer in presence of glucose. It therefore can be used amperometric sensing of glucose. The biosensor has a fast response (<3 s), a detection limit of 0.4 μM (which is 50-fold lower compared to the biosensor prepared by drop-casting solutions of the same materials onto an GCE), and a linear response in the 0.4 μM to 2 mM concentration range (which again is much better than that of the biosensor prepared by the drop-casting method). Other features include high reproducibility, long-time storage stability, and satisfactory selectivity. We presume that the direct single-step electrodeposition of this nanocomposite offers a promising approach towards novel types of highly sensitive and stable electrochemical biosensors.

Figure

We describe a fast and easy way for the fabrication of graphene-chitosan-GOx film by one-step electrodeposition under controlled potential. The direct electron transfer reaction of GOx immobilized on graphene-chitosan hybrids is observed, and therefore can be used for amperometric sensing of glucose. The biosensor shows a fast response (<3 s), a detection limit of 0.4 μM, and a linear response in the 0.4 μM to 2 mM concentration range.

Shanli Yang and Zhenzhen Lu contributed equally.