Protein adsorption behavior on reduced graphene oxide and boron-doped diamond investigated by electrochemical impedance spectroscopy

Abstract

Abstract As advanced and promising carbon materials, we found reduced graphene oxide (rGO) and boron-doped diamond (BDD) demonstrated special impedance response regarding protein adsorption compared with other materials. According to the results of electrochemical impedance spectroscopy (EIS), rGO showed two time constants (two semicircles in Nyquist plot) when exposed to model protein bovine serum albumin (BSA) solutions; BDD showed decreased impedance response when exposed to high concentration of BSA. They demonstrated special but different impedance response upon BSA adsorption. Based on fitting results of EIS data and hypothesis of protein adsorption, protein adsorption model on the interface of protein solution and carbon electrode surfaces have been established, which is applicable to rGO and BDD surface, and is further expected to be applicable to other carbon materials. Besides the in-depth understanding of protein adsorption behavior, this study also indicates a potential way to control the orientations of protein molecules on solid surface.