Hydrothermal Calcification of Sand-Blasted/Acid-Etched Titanium with Improved Corrosion Resistance and Cytocompatibility

Preparing a bioactive surface with a hierarchical micro/nanostructure can improve the osseointegration of titanium implants. In this study, titanium was sand blasted and etched in H2SO4 solution to obtain micro-rough morphology. The samples were then hydrothermally treated in the concentrated CaHPO4 solution at 120–200 °C for 24 h to grow films consisting of anatase TiO2 and hydroxyapatite nanoparticles (size 80–240 nm). The hydrothermally calcified (200 °C) sample exhibited much better corrosion resistance in the salt solution, as well as similar cellular viability and a higher alkaline phosphatase level in the cell tests using MC3T3-E1 cells, in comparison with the polished titanium sample. The hybrid treatment is a facile and effective method to a form bioactive surface with a hierarchical micro/nanostructure on titanium.