ZrO2/DNA-derivated polyion hybrid complex membrane for the determination of hydrogen peroxide in milk

An efficient biosensing substrate based on ZrO2/DNA-derivated polyion complex (PIC) membrane has been developed for the determination of hydrogen peroxide (H2O2) in this study. To fabricate such a PIC membrane, ZrO2 nanoparticles were initially electrodeposited on the bare gold electrode (ZrO2/Au), and deoxyribonucleic acid (DNA)-doped hemoglobin mixture was then assembled onto the ZrO2/Au surface. The double-strand DNA provided a biocompatible microenvironment for the immobilization of biomolecules, greatly amplified the surface coverage of biomolecules on the electrode surface, and improved the sensitivity of the biosensor. The fabricated procedure of the proposed biosensor was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and atomic force microscopy. The performance and factors influencing the performance of the biosensor were also evaluated. Under optimal conditions, the developed biosensor exhibited a well-defined electrochemical behavior toward the reduction of H2O2 ranging from 1.1 mu M to 2.3 mM with a detection limit of 0.5 mu M (S/N=3). The biosensor was applied to the determination of H2O2 in milk with satisfactory results. It is important to note that the PIC membrane provided an alternative substrate for the immobilization of other proteins.