A novel rotating electrochemically anodizing process to fabricate titanium oxide surface nanostructures enhancing the bioactivity of osteoblastic cells

Titanium oxide (TiO 2) surface layers with various surface nanostructures (nanotubes and nanowires) have been developed using an anodizing technique. The pore size and length of TiO 2 nanotubes can be tailored by changing the anodizing time and applied voltage. We developed a novel method to transform the upper part of the formed TiO 2 nanotubes into a nanowire-like structure by rotating the titanium anode during anodizing process. The transformation of nanotubes contributed to the preferential chemical dissolution of TiO 2 on the areas with intense interface tension stress. Furthermore, we further compared the effect of various TiO 2 surface nanostructures including flat, nanotubes, and nanowires on bioactive applications. The MG-63 osteoblastic cells cultured on the TiO 2 nanowires exhibited a polygonal shape with extending filopodia and showed highest levels of cell viability and alkaline phosphatase activity (ALP). The TiO 2 nanowire structure formed by our novel method can provide beneficial effects for MG-63 osteoblastic cells in attachment, proliferation, and secretion of ALP on the TiO 2 surface layer.