Antimicrobial Potential of Copper-Containing Titanium Surfaces Generated by Ion Implantation and Dual High Power Impulse Magnetron Sputtering

The application of antimicrobial surfaces to titanium alloy (Ti) implants would be beneficial to prevent implant-associated infections of joint endoprostheses and osteosyntheses. Copper (Cu) could be advantageously applied for this purpose, since it exhibits a well-known antimicrobial activity and is a trace element in the human body, i.e., it is non-toxic in small concentrations. This approach was evaluated with two plasma-based surface modification procedures: 1) Implantation of Cu ions into Ti by means of plasma immersion ion implantation (PIII) and 2) Coating of Ti surfaces with Cu?Ti films by means of dual high power impulse magnetron sputtering (dual HiPIMS). In this manner, the surfaces could be equipped with various amounts of Cu, as it was analyzed by X-ray photoelectron spectroscopy (XPS). The surfaces released up to 8mmol center dot L-1 of Cu within 24h, measured with atomic absorption spectroscopy (AAS). Hence, the surfaces possessed an antimicrobial potential against typical infect-associated bacteria (Staphylococcus aureus). Surfaces with a higher Cu release prepared by HiPIMS technique revealed a higher antimicrobial effect, while surfaces implanted by PIII were less cytotoxic to osteoblasts (MG-63 cells). These results show that Cu doped and coated implants could be useful for prevention and therapy of implant-associated infections.