Immobilization of Myoglobin on NiO Nanoparticles Matrix for Preparation of Novel Biosensor

Direct electrochemistry that immobilized myoglobin (Mb) on a nanometer-sized NiO nanoparticles matrix modified graphite electrode (GE) and preparation of novel hydrogen peroxide biosensor were studied. The immobilized Mb displayed a couple of stable and well-defined redox peaks with an electron transfer rate constant of 6.48 s−1 and a formal potential of −0.340 V (vs saturated calomel electrode [SCE]) in 0.1 M pH 7.0 PBS. The total surface concentration Γ was 8.06×10−10 mol cm−2. Dimethyl sulfoxide (DMSO) could play an important role in the electron transfer between Mb and the electrode. Spectroscopy analysis of the Mb/NiO/DMSO film showed that the immobilized Mb could retain its natural structure. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging from 0.8 to 24 μM with a detection limit of 0.039 μM at 3σ. The apparent Michaelis-Menten constant KMapp for H2O2 sensor was estimated to be 0.21 mM, sensitivity was 417 mA/M·cm−2, showing a high affinity.