TiO₂ Nanotube Arrays Prepared By Anodic Oxidation And Their Biological Properties

Titanium and its alloys are preferred materials for load-bearing implants in much clinical research because of their attractive properties,such as excellent mechanical strength, biocompatibility,high corrosion resistance.However, the natural titanium oxide film formed on its surface make it bio-inert, it is difficult to achieve chemical bond with bone and form new bone on their surfaces;So, the surface modification has become a main research field of titanium matrix biomedical materials.The aim of the surface modification is to improve the biocompatibility and bioactivity in vivo.In this paper, in order to improve the biocompatibility of pure titanium implant,titania nanotube array layers on titanium surfaces were prepared by electrochemistry anodic oxidation for pure titanium. We detailedly researched titania nanotube arrays fabricated in HF solution, separately discussed the influences of the parameters for the preparation of titania nanotube arrays on the micrograph of the materials, such as anodizing potential, oxidation time, concentration and temperature of the electrolyte, electrolyte systems, heat treatment and so on, investigated mechanism of nanotube arrays formed. The results indicate that with the improve of voltage, nanotubes radial size and thickness will increase; With the increase of the concentration of electrolyte, nanotubes radial dimensions will increase, and the thickness become thinner;With the increase of the temperature of electrolyte, nanotubes radical size have no much change. The high voltage and concentration of HF solution lead to corrosion of the surfaces of TiO2 nanotube arrays. The heat treatment caused crystallization of the amorphous titania nanotube arrays, it contribute to bonding strength with the substrate of titanium. The anodic potential at which nanotubes are formed is related to the F- concentration, with higher potentials requiring electrolytes of higher F- concentration.After the TiO2 nanotube array layers were treated with alkali solution, apatite could more deposite onto the surface. A soldium titanate layer is formed after alkali treatment which play a important role of precipitation of bone-like apatite on titania nanotube arrays surface. With the content and time of alkali treatment are increased, the biomimetic mineralization propertiey and the size of apatite particles are increased; it can be formed a crosslinking compact structure in space.The osteoblast culture test on two samples.The results showed that the modified materials include TiO2 nanotubes obviously promoted cell adhesion and proliferation.The nano-structure can be contribute to improve cell adhesion, proliferation, differentiation. Thus, the modified materials surface had better bioactivity and biocompatibility.