Monitoring of glucose level has a wide application in areas such as medicine and food industry [1]. Nanoparticles have a unique ability to promote fast electron transfer between electrode and the active site of the enzyme [2]. Fe3O4 nanoparticles have been considered for immobilization of desired biomolecules (GOx) because of biocompatibility, low toxicity, etc [3]. In this paper, we report results of the studies relating to preparation, characterization of GOx immobilized onto CH-Fe3O4 nanocomposite film deposited onto FTO coated glass surface. Fe3O4 was produced by the chemical co-precipitation method [4]. A Chitosan (0.50%) solution was prepared by dissolving CH in acetate buffer. Fe3O4 nanoparticle was dispersed in the CH solution by sonicating at room temperature. The film of nanocomposite was fabricated by dip-coating solution of CH–Fe3O4 composite onto a FTO surface and allowing it to dry at room temperature for about 12 h. Solution of GOx (1mg/ml in phosphate buffer, 50 mM, and pH 7.0) was immobilized on to CH-Fe3O4/FTO electrode by physisorption. This bioelectrode was allowed to dry at room temperature for about 5 h. Electrochemical studies have been carried out on a potentiostat/galvanostat (μ Autolab Type III) using a three-electrode system. This GOx/CH–Fe3O4/FTO nanocomposite bioelectrode has linear response range of 0 to 50 mM with correlation coefficient of 0.999. The detection limit of the electrode is 0.3 mM (S/N=3). The highest sensitivity was noted at about 0.04 μA/mM cm2.

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