Enhancing osteoblast-affinity of titanium scaffolds for bone engineering by use of ultraviolet light treatment

Ultraviolet (UV) treatment immediately prior to use is attracting attention as an effective surface conditioning method for titanium to improve osteoblast-affinity. The affinity of titanium to osteoblasts in two-dimensional plate culture has been well studied, but that in three-dimensional cultures remains unclear. Here, we examined the effect of UV treatment on titanium scaffolds, comprising micro-thin titanium fibers, used in bone engineering. Titanium scaffolds, with and without UV treatment, were seeded with rat bone marrow derived osteoblasts, and the number of cells attached to scaffolds and osteoblastic phenotype in the cultures were examined. UV treatment improved the wettability of scaffolds and significantly reduced the percentage of surface carbon. Along with these physicochemical changes in the scaffolds, cell attachment increased by a factor of 1.3 as compared to that of the untreated control. In addition, alkaline phosphatase activity and calcium deposition significantly increased by a factor of 2.3 and 2.0, respectively. Robust formation of mineralized structures consisting of clear peaks of calcium and phosphorus was observed in the UV-treated scaffolds. The observed increase in osteoblast affinity and capability of mineralized matrix formation indicates the potential use of UV-treated titanium scaffolds for bone engineering.