Micro/nanostructural porous surface on titanium and bioactivity

Abstract

Porous surfaces can improve both early fixation and long-term stabilization of implants by contrast with smooth surfaces. In this study, a microporous surface on titanium was prepared by acid etching and the size of micropores ranged from 1 to 60 microm. The micro/nanostructural porous layer on this microporous surface was obtained by acid etching and anodization. In this micro/nanostructural porous layer, the diameter of nanotubes was about 100 nm. After heat treatment at 450 degrees C for 6 h, the oxides on micro/nanostructural surface transformed into anatase crystals and the grain size of anatase was about 20 nm. The bioactivity of samples was investigated respectively in simulated body fluid and a bovine serum albumin (BSA) solution. The information of specimen surfaces was detected using scanning electron microscope, X-ray diffractometer, and attenuated total reflection Fourier transform infrared spectroscope. The results showed that the sample with micro/nanostructural porous surface and anatase had excellent bioactivity under nonpretreatment. It had more hydroxyapatite (HA) formation and faster BSA adsorption than other samples under the same conditions. Besides, the HA coating on the micro/nanostructure surface had larger range thickness, no microcrack, and no separated interface from substrate. Therefore, this micro/nanostructural porous surface may be an ideal modification layer for preparing bioactive implants.