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.