Effect of photofunctionalization on fluoride-treated nanofeatured titanium

The objective of this study was to evaluate the effect of ultraviolet light treatment, known as photofunctionalization, on the biological and osseointegration capability of nanofeatured titanium created by a combination of sandblasting and hydrofluoric acid treatment. Titanium samples in disk and cylinder forms were photofunctionalized by treatment with ultraviolet light for 15 min. The nanofeatured surface was converted from hydrophobic to superhydrophilic after photofunctionalization. The strength of osseointegration measured by a biomechanical push-in test in a rat model was stronger for photofunctionalized implants than for untreated implants by 2.2 and 2.3 times, respectively, at the early (week 2) and late (week 4) stages of healing, implying that photofunctionalization did not only accelerate but also increased the degree of osseointegration. Culture studies using bone marrow-derived osteoblasts showed that the attachment, spread, and functional phenotypes of osteogenic cells, such as alkaline phosphatase activity and mineralization, were remarkably increased on photofunctionalized titanium. In conclusion, photofunctionalization substantially increased biological and osseointegration capability of a nanofeatured titanium surface. In light with proven effectiveness on microfeatured surfaces in the literature, photofunctionalization may provide a novel and practical avenue to further improve osseointegration capability of implants in a wide range of surface morphology with micro-to-nano features.