In this study, we present a novel strategy for hierarchical antibacterial implant coating by controlling structural and componential features as regulators of surface bactericidal property. Anodized titanium dioxide nanotubes and self-polymerized polydopamine were both used as preliminary antibacterial agents with a significant positive effect on surface bioactivity. At the same time, the storage capacity of nanotubes and the in situ reduction activity of polydopamine can introduce large amounts of strong attached silver nanoparticles for enhanced stable antibacterial performance. The surface morphology, chemical composition, and hydrophilicity had been thoroughly characterized. The sustained silver release performances were continuously monitored. The successively in vitro inhibition on Staphylococcus aureus growth of titanium dioxide nanotube, polydopamine layer and silver nanoparticles demonstrated the hierarchical antibacterial property of the final silver nanoparticles-incorporated polydopamine-modified titanium dioxide nanotube coating (silver/polydopamine/nanotube). Moreover, the bioactivity investigation indicated the vital role of polydopamine-modified titanium dioxide nanotube coating on preserving healthy osteoblast activity at the implant interface. The unique hierarchical coating for titanium implant may be a promising method to maximize antibacterial capacity and maintain good cellular activity at the same time.
Keywords: Titanium implant; antibacterial coating; hierarchical effect; sliver nanoparticles; sustained release; titanium dioxide nanotubes.