Surface modification of TiNb alloys by hydrothermal-precalcification treatment and its excellent in vitro osteogenic bioactivity

Abstract

The superb comprehensive mechanical properties of titanium and its alloys make them ideal materials for artificial bone repair. However, the osseointegration between normal tissue and implant is lengthy due to the relatively poor surface osteogenic bioactivity of titanium-based materials. For the sake of accelerating the bone healing process, surface modification for the titanium- based implant is therefore of great necessity. In this paper, the novel [Formula: see text]-typed TiNb alloy with good biocompatibility was modified by a simple hydrothermal-precalcification method. The experimental results demonstrate that these hydrothermally prepared TiNb alloys were coated by a superhydrophilic Nb-doped TiO2 film with a hierarchical micro-nanostructure. After subsequent pre-calcification treatment, calcium and phosphorus species with low content were successfully introduced into the film without morphological change. The simulated body fluid (SBF) soaking experiments show that the TiNb alloy with the two-step surface treatment represented excellent in vitro bioactivity. After incubating in SBF for only 1 day, the TiNb alloy surface was thoroughly coated with a layer of newly formed spherical hydroxyapatite clusters. Comparatively, no obvious hydroxyapatite was deposited on the TiNb alloy surface with the one-step hydrothermal treatment even after five days of incubation in SBF. As a result, the hydrothermal–precalcification treatment is an ideal method to improve the osteogenic bioactivity of TiNb alloy, which can be further extended to surface modification of other titanium-based implant materials.