Electrodeposited nanoscale zinc oxide particles: facilitating the electron transfer of immobilised protein and biosensing

The electron transfer of redox-active sites of immobilised haemoglobin (Hb) has been studied by voltammetric experiments. The electrode surface was modified by nanoparticles (NPs) to make a suitable substrate for electric wiring of protein molecules and efficient electron transferring. Hence, the Hb/zinc oxide NPs/platinum electrode was prepared by chronoamperometric deposition of the NPs and immobilisation of protein molecules. The electrochemical behaviour of the prepared biosensor was quasi-reversible and showed a pair of redox peaks with a formal potential (E0′) of 214 mV. Additionally, the electron transfer rate constant (ks) of immobilised Hb was about 0.621 s−1. Biocatalytic reduction of hydrogen peroxide was also examined on the prepared biosensor. Result indicated to good sensitivity, wide linear range and low detection limit of 6 μM.