Plasma-treated nanostructured TiO₂ surface supporting biomimetic growth of apatite

Although some types of TiO₂ powders and gel-derived films can exhibit bioactivity, plasma-sprayed TiO₂ coatings are always bioinert, thereby hampering wider applications in bone implants. We have successfully produced a bioactive nanostructured TiO₂ surface with grain size smaller than 50 nm using nanoparticle plasma spraying followed by hydrogen plasma immersion ion implantation (PIII). The hydrogen PIII nano-TiO₂ coating can induce bone-like apatite formation on its surface after immersion in a simulated body fluid. In contrast, apatite cannot form on either the as-sprayed TiO₂ surfaces (both 50 nm grain size) or hydrogen-implanted TiO₂ with grain size larger than 50 nm. Hence, both a hydrogenated surface that gives rise to negatively charged functional groups on the surface and small grain size (2 coatings, which are generally recognized to have excellent biocompatibility and corrosion resistance as well as high bonding to titanium alloys, makes them more superior than many current biomedical coatings. © 2005 Elsevier Ltd. All rights reserved.