Antibacterial nano-structured titania coating incorporated with silver nanoparticles

Titanium (Ti) implants are widely used clinically but post-operation infection remains one of the most common and serious complications. A surface boasting long-term antibacterial ability is highly desirable in order to prevent implant associated infection. In this study, titania nanotubes (TiO2-NTs) incorporated with silver (Ag) nanoparticles are fabricated on Ti implants to achieve this purpose. The Ag nanoparticles adhere tightly to the wall of the TiO2-NTs prepared by immersion in a silver nitrate solution followed by ultraviolet light radiation. The amount of Ag introduced to the NTs can be varied by changing processing parameters such as the AgNO3 concentration and immersion time. The TiO2-NTs loaded with Ag nanoparticles (NT-Ag) can kill all the planktonic bacteria in the suspension during the first several days, and the ability of the NT-Ag to prevent bacterial adhesion is maintained without obvious decline for 30 days, which are normally long enough to prevent post-operation infection in the early and intermediate stages and perhaps even late infection around the implant. Although the NT-Ag structure shows some cytotoxicity, it can be reduced by controlling the Ag release rate. The NT-Ag materials are also expected to possess satisfactory osteoconductivity in addition to the good biological performance expected of TiO2-NTs. This controllable NT-Ag structure which provides relatively long-term antibacterial ability and good tissue integration has promising applications in orthopedics, dentistry, and other biomedical devices.