In vitro analysis of cell compatibility of TiCuN films with different Cu contents

Abstract

TiN film has been used in the surface modification of orthopaedic implants due to its favorable biocompatibility and tribological properties. Copper ions have low toxicity and biological functions. In this study, copper was doped to TiN film to enhance the viability of osteoblast and decrease the inflammatory response of macrophages for TiCuN film applications in orthopaedic implants. TiCuN films with different Cu contents were deposited on Si wafers by direct current (DC) magnetron sputtering technique. The effects of Cu content on the TiCuN film structure, surface morphology, and surface energy were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements. The results demonstrated that Cu doping could suppress the columnar structure of TiN films, change the surface of the TiN film from hydrophilic to hydrophobic, and reduce its surface energy. When the Cu content reached 11.1 at.%, Cu nanocrystals were formed in the TiCuN film. The biocompatibility of the TiCuN films with different Cu contents was analyzed based on osteoblasts and macrophages. The results demonstrated that the viability and morphology of osteoblasts on the TiCuN films with a Cu content of 2.4 at.% were significantly improved compared with those of the CoCrMo alloy and TiN film. The inflammatory response induced by the TiCuN films with Cu contents of 2.4 and 4.2 at.% was lower than that induced by the CoCrMo alloy and TiN film without Cu doping. The TiCuN film with optimum Cu content of 2.4 at.% promoted the viability of osteoblasts and reduced the inflammatory response of macrophages.