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Abstract: A convenient and effective strategy for fabrication of hydrogen peroxide biosensor based on sodium alginate (SA) and polyvinyl butyral (PVB) as matrices was reported in this paper. The horseradish peroxidase (HRP) and SA were electro-co-deposited onto the surface of gold electrode, and the HRP–SA/Au electrode was further coated with PVB. The interaction between HRP and SA was characterized by UV–vis absorption spectroscopy, and the fabricating process of biosensor was characterized by electrochemical impedance spectroscopy (EIS). The electrochemical characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. Experimental conditions were investigated which influence the performance of the biosensor, such as pH, and applied potential. The biosensor showed a linear response to H2O2 over a concentration range from 7.0×10−6 to 4.1×10−3 M with a detection limit of 1.8×10−6 M based on a signal-to-noise ratio of 3 under optimum conditions. The value of HRP in the composite was evaluated to be 1.38mM. The biosensor obtained from this study possesses high sensitivity, good reproducibility, and long-term stability. [Copyright &y& Elsevier]

Abstract: A novel amperometric hydrogen peroxide biosensor based on the immobilization of horseradish peroxidase (HRP) on DNA–silver nanohybrids (DNA–Ag) and poly(diallyldimethylammonium chloride) (PDDA)-protected gold nanoparticles (PDDA–Au) was successfully fabricated by combining the self-assembly technique with an in situ electrochemical reduction of the DNA–Ag+ complex. The preparation process of modified electrode was characterized with UV–vis absorption spectroscopy, transmission electron microscopy (TEM) and atomic force microscope (AFM). The electrochemical characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. Experimental conditions influencing the biosensor performance such as pH, potential were optimized. The resulting biosensor (HRP/DNA–Ag/PDDA–Au/DNA–Ag/Au electrode) showed a linear response to H2O2 over a concentration range from 7.0μM to 7.8mM with a detection limit of 2.0μM (S/N=3) under optimized conditions. The apparent Michaelis–Menten constant () was evaluated to be 1.3mM. The sensor exhibited high sensitivity, good accuracy and an acceptable stability. [Copyright &y& Elsevier]