Alginate copper oxide nano-biocomposite as a novel material for amperometric glucose biosensing

A novel amperometric glucose biosensor based on alginate-CuO nano-biocomposite and glucose oxidase (GOD) film was developed and characterized. The properties of the alginate-CuO-GOD film were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric measurements were employed to characterize the analytical performance of the biosensor. Several parameters including amount of alginate, concentration of GOD and cross-linkers, amount of CuO nanoparticles, and effect of pH were studied and optimized. Under optimal conditions, the developed alginate-CuO-GOD biosensor was shown to have two linear ranges; from 0.04mM to 3mM (with a correlation coefficient of 0.9996 and the sensitivity of 30.443μAmM^-1cm^-2) and from 4mM to 35mM (with a correlation coefficient of 0.9994 and the sensitivity of 7.205μAmM^-1cm^-2). The overall detection limit was estimated to be 1.6μM (signal-to-noise ratio of 3) and the K_m value of 2.82mM. The biosensor exhibited rather good performance with long-term stability (remainder of activity is 78% after 15days) and significant specificity for glucose when compared to possible interfering molecules such as ascorbic acid, uric acid and acetaminophen.