Protein adsorption on implant metals with various deformed surfaces

The adsorption of proteins has great influence on the biocompatibility, lubrication and corrosion properties of implantable metals. The subsurface microstructure of metals can be easily changed during the manufacturing or service processes and it is easily ignored. The same chemical composition but with various surface microstructures can result in very different adsorption behaviour. In this study, mechanical polishing, electrochemical polishing and shot peening methods were used to generate different gradient deformed surfaces for CoCrMo alloys. The increase of the residual compressive stress and the decrease of grains to a nano-size on the deformed subsurface can effectively enhance the activity of metal atoms and improve the element diffusion, that is helpful in forming a more compact passive film. This can increase the contents of oxides on the surface, and then enhance the electrostatic force and increase the surface's positive charge density as well as adsorption sites. All of the above facilitated the adsorption of the negatively charged albumin onto the alloy surface.