Preparation and Cytocompatibility of Nanoporous SiO₂-TiO₂ Coatings by Plasma Spraying and HF Etching

SiO₂-TiO₂ coatings were prepared by atmospheric plasma spraying followed by hydrothermal treatment in a solution of hydrogen fluoride. The as-sprayed coatings mainly consisted of rutile and quartz phases, which remained relatively unchanged during etching. All treated coatings have the typical characteristics of plasma-sprayed deposits, exhibiting rough surfaces with many splats. Differences in surface structure can be observed, however, at the nanoscale, depending on treatment conditions. Treatments of 60 min at 100 °C appear to be most beneficial, resulting in nanoporous coatings that are shown to promote cell proliferation and, in past studies, have been found to improve osteoblast adhesion.