The response of bioactive titanium surfaces with different structure to UVC-irradiation to eliminate the negative effect on biological properties during aging time.

The biological aging of titanium implants affects the service lifetime negatively in clinical applications, and Ultraviolet (UV) irradiation is an applicable method to overcome the biological aging. This study investigated the changes in surface characteristics and biological properties of bioactive titanium surfaces with different structure and topography after Ultraviolet C (UVC) irradiation. The bioactive titanium surfaces were prepared by anodizing (AO), sandblasting and acid-etching (SLA), acid-alkali etching (AA), alkali-heat etching (AH) methods. Samples were stored at dark for 7 weeks to simulate biological aging process and then irradiated by UVC for 2 h. The results showed that the hydroxyl groups (Ti-OH) on surfaces, which are crucial to enhance the biological properties, were easier to be generated on AO surfaces by UVC-irradiation, owing to a mixture of anatase and rutile on surfaces. UVC-irradiation had the strongest effect on AO surfaces to enhance the bioactivity in bone-like apatite deposition and better biocompatibility in mesenchymal stem cells (MSCs) attachment and proliferation. Therefore, titanium surfaces with a mixture phase of anatase and rutile have the potential to effectively utilize the benefits of UVC-irradiation to overcome the negative effects of the biological aging and have a promising clinical application prospect.