Effects of storage medium and UV photofunctionalization on time-related changes of titanium surface characteristics and biocompatibility.

Storage in aqueous solution and ultraviolet (UV) photofunctionalization are two applicable methods to overcome the biological aging and increase the bioactivity of titanium. As information regarding the combined effects of storage medium and UV photofunctionalization has never been found in published literatures, this study focused on whether appropriate storage methods and UV photofunctionalization have synergistic effects on the biological properties of aged titanium surfaces. Titanium plates and discs were sandblasted and acid etched and then further prepared in five different modes as using different storage mediums (air or dH2 O) for 4 weeks and then with or without UV treatment. The surface characteristics were evaluated with scanning electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. MC3T3-E1 cells were cultured on the surfaces, and cellular morphology, proliferation, alkaline phosphatase activity, and osteocalcin release were evaluated. The results showed that nanostructures were observed on water-stored titanium surfaces with a size of about 15 × 20 nm(2) . UV treatment was effective to remove the hydrocarbon contamination on titanium surfaces stored in either air or water. UV photofunctionalization further enhanced the already increased bioactivity of modSLA on initial cell attachment, proliferation, alkaline phosphatase activity, and osteocalcin release. Overall, UV photofunctionalization was effective in further enhancing the already increased bioactivity by using dH2 O as storage medium, and the effect of UV treatment was much more overwhelming than that of the storage medium.