Enhancement of Hydrophilicity of Nano-Pitted TiO(2) Surface Using Phosphoric Acid Etching

Our research group developed a novel nano-pitted (NP) TiO(2) surface on grade 2 titanium that showed good mechanical, osteogenic, and antibacterial properties; however, it showed weak hydrophilicity. Our objective was to develop a surface treatment method to enhance the hydrophilicity of the NP TiO(2) surface without the destruction of the nano-topography. The effects of dilute and concentrated orthophosphoric (H(3)PO(4)) and nitric acids were investigated on wettability using contact angle measurement. Optical profilometry and atomic force microscopy were used for surface roughness measurement. The chemical composition of the TiO(2) surface and the oxidation state of Ti was investigated using X-ray photoelectron spectroscopy. The ccH(3)PO(4) treatment significantly increased the wettability of the NP TiO(2) surfaces (30°) compared to the untreated control (88°). The quantity of the absorbed phosphorus significantly increased following ccH(3)PO(4) treatment compared to the control and caused the oxidation state of titanium to decrease (Ti(4+) → Ti(3+)). Owing to its simplicity and robustness the presented surface treatment method may be utilized in the industrial-scale manufacturing of titanium implants.