Novel fabrication of nano-rod array structures on titanium and in vitro cell responses

Nano-scale rod arrays of titania were fabricated on titanium surface by a glass phase topotaxy growth (GPT) method, which was featured by an interfacial reaction between sodium tetraborate coating and the preheated metallic titanium at elevated temperature. The samples were characterized by thin-film X-ray diffraction (XRD), scanning electron microscope (SEM), profilometer and contact angle measurement. Thin-film XRD analysis indicated that the nano-rod arrays were composed of pure rutile titania phase. SEM images showed that these rutile rods were 100-200 nm wide and 1-2 microm long. The nano-rod arrays had significantly higher average roughness (P < 0.05) and greater hydrophilicity (P < 0.05) compared to the control. Human embryonic palatal mesenchymal (HEPM) cells were grown to evaluate in vitro cell responses to the nano-rod array structures in terms of cell attachment and proliferation. An equivalent high attachment rate of 94% was observed after 4-h incubation, but a lower proliferation rate was observed on the nano-rod array after 12-day culture compared to the control (P < 0.05).