A novel glucose biosensor has been presented in this paper. First, L-cysteine was immobilized onto a gold electrode to form a positively charged surface, then nano-Prussian blue was assembled on the modified surface as an electron transfer mediator. Finally, the hybrid film of chitosan-nano gold and glucose oxidase (GOD) was immobilized on the electrode to fabricate the proposed biosensor. The modifying process was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and transmission electron microscopy (TEM). And the effects of applied potential and pH on the response currents were also investigated. Under optimal conditions, the resulting biosensor displayed a rapid response to glucose and the linear range of the biosensor was from 3.0×10－6 to 1.0×10－3 mol/L with a detection limit of 1.6×10－6 mol/L (S/N＝3). Moreover, the interferents influencing the proposed biosensor were researched in detail, and the biosensor possessed excellent selectivity and good stability.

Key words: L-cysteine, nano-Prussian blue, glucose biosensor, nano-gold, chitosan