Antibacterial properties of nanostructured Cu–TiO₂surfaces for dental implants

The influence of copper derived TiO₂ surfaces (nCu-nT-TiO₂) on the death of nosocomial Staphylococcus aureus (Sa) and Escherichia coli (Ec), was investigated. TiO₂ nanotube (nT-TiO₂) arrays were fabricated by anodic oxidation of pure titanium sheets in fluorhydric solutions, leading to surface nanostructuration and creation of specific reactive sites. Copper nanocubes with a mean size of 20 nm have been synthesized and deposited on the nT-TiO₂ surface by pulsed electrodeposition from a copper sulphate solution. Scanning Electron Microscopy (SEM) reveals that Cu nanocubes are both inserted into the TiO₂ nanotubes and on the nanotube edges. X-ray Photoemission Spectroscopy (XPS) and SEM-EDX confirm the metallic nature of copper nanoparticles, covered with a thin mixed CuO-Cu₂O thin layer. As the adsorption of proteins is one of the early stages of biomaterial surface interactions with body fluids before bacterial colonization, Infrared Spectroscopy (IR) in reflection-absorption mode, SEM and XPS have been used to follow the evolution of nCu-nT-TiO₂ surfaces when exposed to a simulated plasma solution containing Bovine Serum Albumin (BSA). Finally bacterial tests have revealed a high biocide potential of the nCu-nT-TiO₂ surface, which leads to the entire death of SA and EC.