Complex interplay of surface properties in modulating antibacterial activity of Ti50Zr alloys

This study investigates the antibacterial performance of Ti50Zr alloys modified by anodization and ZnO coating, emphasizing the complex interplay of surface properties that influence bacterial inhibition. Three surface morphologies were created via anodization: compact oxide (CO), nanotube (NT), and nanochannels (NC). The antibacterial activity of the modified surfaces was evaluated against Escherichia coli using inhibition rates and bactericidal ratios. The results showed that surface roughness and morphology significantly affected antibacterial efficiency, with the Ti50Zr NC structure exhibiting the highest inhibition rate (60%). ZnO coating further enhanced antibacterial activity, particularly with Ti50Zr NCZnO, which showed the best performance (75% inhibition). Additionally, Ti50Zr NTZnO demonstrated a significant improvement in antibacterial efficiency, with ZnO nanoparticles (10 nm) playing a key role in membrane penetration. The study also examined the impact of surface energy, wettability, and electrochemical properties on bacterial adhesion and killing mechanisms. These findings underscore the critical influence of surface nanostructuring, ZnO nanoparticle size, and coating on enhancing the antibacterial properties of Ti50Zr, highlighting the complexity of surface interactions in optimizing biomaterials for medical applications.