Direct electrochemistry and electrocatalysis of heme proteins immobilized on self-assembled ZrO2 film

A novel method for fabricating hydrogen peroxide (H2O2) sensor has been presented based on the self-assembly of ZrO2 nanoparticles with heme proteins on functional glassy carbon electrode. The immobilized proteins realized their direct electrochemistry with the formal potential of −0.032 V for hemoglobin and −0.026 V for myoglobin in pH 6.0 PBS, respectively. Electrochemical impedance spectroscopy and cyclic voltammetry were applied to characterize the self-assembly process and study the electrochemical behaviors of the immobilized proteins. UV-Vis spectra results suggested that proteins in ZrO2 films retained their bioactivity, hence they exhibit good electrocatalytic behaviors towards the reduction of substrate H2O2. As a result, a kind of novel third-generation biosensors for H2O2 was developed. The resultant heme-protein electrode exhibited fast amperometric response (within 10 s) to H2O2, excellent stability, long-term life (more than one month) and good reproducibility.