An electrochemical biosensor for analysis of Fenton-mediated oxidative damage to BSA using poly-o-phenylenediamine as electroactive probe

A sensitive electrochemical procedure based on bovine serum albumin (BSA)/poly-o-phenylenediamine (PoPD)/carbon-coated nickel (C-Ni) nanobiocomposite film modified glassy carbon electrode (BSA/PoPD/C-Ni/GCE) has been developed to explore the electrochemical detection of BSA damage induced by hydroxyl radical. It is the first time that the electrochemical method has been applied for the analysis of Fenton-mediated oxidative damage to proteins. The hydroxyl radical was generated by Fenton reaction (Fe2+/H2O2), which was also validated by ultraviolet-visible (UV-vis) spectroscopy. The decrease in intensity of the PoPD oxidation signals was used as an indicator for the detection of BSA damage. Damage to BSA was also validated by horizontal Attenuation Total Reflection Fourier Transform Infra-red (ATR-FTIR) spectroscopy and the change of protein carbonyl group content achieved by UV-vis spectroscopy. Effects of H2O2 concentration, the ratio of Fe2+ and H2O2 and incubation time on BSA damage were examined. Protections of BSA from damage by antioxidants were also investigated. These conclusions demonstrated that the proposed electrochemical method is expected to the further application for protein damage studies.