Surface modification of Ti-6Al-4V alloy for osseointegration by alkaline treatment and chitosan-matrix glass-reinforced nanocomposite coating

Individual and combined treatments of alkaline (NaOH) and chitosan/bioactive glass (SiO2-CaO-MgO) nanocomposite coating were applied on Ti-6Al-4V alloy surfaces with the objective of investigating and improving i) wettability, ii) apatite-formation ability, iii) corrosion resistance, and iv) biocompatibility. Individual applications of each surface treatment were found to enhance hydrophilicity, apatite-forming ability, corrosion resistance, and cytocompatibility (MG-63 cells). The most improved properties, except apatite-formation ability, were obtained using the combined treatment yielding a reduction of 64 and 93 % in sessile contact angle and corrosion rate, respectively, than the untreated substrate. These improvements originate from the desired roughness and apatite-formation ability of the alkaline treatment and the appropriate biocompatibility and corrosion protection of the nanocomposite coating. That is, the combined application of alkaline treatment and chitosan nanocomposite coating is demonstrated as a promising surface-engineering strategy for hard-tissue replacement applications.