Au/CeO2–chitosan composite film for hydrogen peroxide sensing

Au nanoparticles (AuNPs) were in situ synthesized at the cerium dioxide nanoparticles (CeO2NPs)–chitosan (CS) composite film by one-step direct chemical reduction, and the resulting Au/CeO2–CS composite were further modified for enzyme immobilization and hydrogen peroxide (H2O2) biosensing. Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), UV–vis spectra and electrochemical techniques have been utilized for characterization of the prepared composite. The stepwise assembly process and electrochemical performances of the biosensor were characterized by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and typical amperometric response (i–t). The Au/CeO2–CS composite exhibited good conductibility and biocompatibility, and the developed biosensor exhibited excellent response to hydrogen peroxide in the linear range of 0.05–2.5 mM (r = 0.998) with the detection limit of 7 μM (S/N = 3). Moreover, the biosensor presented high affinity (image), good reproducibility and storage stability. All these results demonstrate that the Au/CeO2–CS composite film can provide a promising biointerface for the biosensor designs and other biological applications.