LAUSR

Abstract In order to take advantages of the structural complexity of hierarchical topography and benefits of Cu, novel Cu-incorporated micro/nano-topographical coatings were developed on titanium (Ti) substrates using micro-arc oxidation (MAO) and hydrothermal treatment. A post heat treatment was employed to alter the morphology of the nanostructures and modulate the release of Cu2+. The structural evolution, phase composition, surface wettability, ion release and protein adsorption of the coatings were investigated. The results showed that the MAO-fabricated coating (denoted as MAO surface) was composed of porous TiO2 matrix distributed with CaO, SiO2 and CaSiO3 amorphous compounds. After hydrothermal treatment, a thin layer of nano-particles (20 nm in diameter) composed of CuO and calcium silicate hydrate formed on MAO surface (denoted as MAO-HT surface). These nano-particles grew to larger ones (65 nm in diameter) composed of crystallized CaO·3CuO·4TiO2 and CaO·TiO2·SiO2 after post heat treatment (denoted as MAO-HT2 surface). Moreover, the ion release rate and surface hydrophilicity of various coatings followed the trend: MAO surface > MAO-HT surface > MAO-HT2 surface. The amounts of adsorbed proteins were comparable on all surfaces. Furthermore, SaOS-2 cell response to various surfaces was investigated. The results showed that the viability of cells was significantly inhibited on MAO-HT surface due to the cyto-toxicity of high concentration Cu2+ release. However, the attachment, proliferation and differentiation of SaOS-2 cells were enhanced on MAO-HT2 surface compared to MAO surface. The results indicate that modifying Ti surface with hierarchical micro/nano-topography could lead to enhanced osteoblast response.