The Effects Of Annealing Temperatures On Corrosion Behaviors,Mechanical Properties And Bioactivity Of TiO₂ Nanotubes

Titania nanotube is a great potential of in medical implant applications, especially in oral and orthopedic surgery, for its easy fabrication, excellent controllability and good cytocompatibility. Tanium dioxide?TiO₂? nanotubes can accelerate the adhesion and differentiation of osteoblasts, but their biocompatibility is still controversial and little is known about the effect of annealing temperature on corrosion behaviors, mechanical properties and cell behaviors. The aim of this study was to investigate the effects of annealing temperature on corrosion behaviors, mechanical properties and ell behaviors of TiO₂ nanotubes formed via anodic oxidation.Methods: TiO₂ nanotube arrays were formed via anodic oxidation. Field emission scanning electron microscopy?FE-SEM? was utilized to observe the surface topography of the prepared specimens. The crystalline structure of the nanotubes was identified by X-ray diffraction?XRD? and the chemical binding energy of the sample surfaces was analyzed by X-ray Photoelectron Spectroscopy?XPS?. The nanoindentation test measured the nanomechanical characteristics of the TiO₂ nanotubes, including hardness and Young's modulus. Electrochemical impedance spectroscopy?EIS? were carried out to evaluate the corrosion behavior of annealed TiO₂ nanotubes in simulated body fluids?SBF?. Moreover, the effects of annealing temperature on osteogenic differentiation and cytotoxicity of rat's bone marrow mesenvhymal stem cells?r BMSCs? was investigated through 3D culture. ALP activity was normalized to total protein measured with the Bio-Rad protein assay?Bio Rad, Hercules, USA?.Results: The amorphous nanotube layers are more efficient for promoting the differentiation of osteoblasts than the anatase structure and mixture of anatase and rutile via observed osteoblastic differentiation. The nanomechanical test results illustrated that the Young's modulus and surface hardness of TiO₂ nanotube coated substrates are increased with increasing annealing temperatures. The scratch test results showed that anneal at 200? can improve the adhesion strength of TiO₂ nanotube-coated substrates by up to 195.8 m N. The friction coefficient of TiO₂ nanotubes annealed at 300?, 450? and 600? are higher than the sample annealed at 200? from the tribological test result. In the current study, the electrochemical results indicated that the amorphous nanotube layers showed a better corrosion resistance than the anatase nanotube layer and mixture of anatase and rutile layer in simulated biofluid.