An overview of protein adsorption on metal oxide coatings for biomedical implants

Surface modification of biomaterials can improve the performance and lifetime of current metallic implantable devices. Metal oxide coatings represent a potential surface modification to enhance the biocompatibility and other biological-related properties, such as the biocorrosion resistance of the metallic implants. In order to design biocompatible metal oxide coatings with tailored properties, it is necessary to get a deeper understanding of the foreign surface–biological interactions, such as the protein–surface interaction, which is the initial process occurring at the implant-biological ambiance contact. By understanding such interaction and the influence of the physicochemical properties of the oxide films on it; then, it might be possible to properly design oxide coatings for a large variety of implant devices from blood to bone contacting implants. Along the paper, different examples are presented in order to support the importance of the protein–surface interaction as a first indicator of biocompatibility and biofunctionality, as well as the existing correlation between protein adsorption and the physicochemical surface properties of metal oxide films.