Preparation of TiO₂ Nano-Flower Coating on Ti Substrates with Good Physical Sterilization Effect and Biocompatibility

We report a facile solution method to form titanium oxide (TiO₂) nano-flower structure on the titanium (Ti) substrates for realizing good physical sterilization and biocompatibility. We first prepare TiO₂ nanotubes (NT) with a diameter of about 80–100 nm and a length of about 5 μm on Ti substrates by anodization, which is utilized as precursor. Then, we employ immersion treatment in different concentrations of phosphoric acid solution at 75 °C for 5 h to realize the transformation from TiO₂ NT to TiO₂ nano-flower structure. In addition, we studied the effects of phosphoric acid concentration (1 wt%, 2.5 wt%, 5 wt% and 10 wt%) on the TiO₂ nano-flower structure, and the antibacterial properties and biocompatibility of the TiO₂ nano-flower structure. The results show that TiO₂ nano-flower structure become larger and thicker with the increase in the phosphoric acid concentration, and the thickness of the coating can reach 6.88 μm. Meanwhile, the TiO₂ nano-flower structure shows good physical sterilization effect, especially for the TiO₂ nano-flower structure formed in 10 wt% H₃PO₄ solution, the antibacterial rate can reach 95%. In addition, the TiO₂ nano-flower structure have no toxicity to the osteoblasts and support cell growth.