Effect of surface energy on protein adsorption behaviours of treated CoCrMo alloy surfaces

Abstract

CoCrMo alloys have been used as biomedical materials for decades. During long-term service in the body environment, however, proteins adsorbing onto the surface of implant can cause their spontaneous corrosion and even the release of toxic ions, which may cause long-term damage to patients. It is essential to understand the key factors affecting protein adsorption and how it can alter corrosion reactions. In this study, the surface energy of a CoCrMo alloy was changed through various oxidation processes. Surface analysis techniques, such as XPS, AES, and GIXRD were used to characterise the chemical properties of the surfaces of modified CoCrMo alloys. Surface topography and potential images of samples after bovine serum albumin (BSA) adsorption were acquired by AFM/SKPFM. The results show that with the increase of the oxidation temperature, the hydrophilicity of the samples was enhanced. With the increase in oxidation time at the same temperature, the surface energy of the samples increased, the dispersion component increased, and the polar component decreased. As a result, the amount of BSA adsorbed on the surfaces decreased, and this was affected more by the polar component than by other components, which was due to the electrostatic and hydrophobic interactions.