Osteoblast differentiation with titania and titania-silica-coated titanium fiber meshes

Two surface-reactive sol-gel coatings, namely titania (TiO2) and a mixture of titania and silica (TiSi), were applied to titanium fiber meshes. Differentiation of rat bone marrow stromal cells toward an osteogenic phenotype with coated and uncoated (cpTi) substrates was compared. The amount of DNA in cpTi and TiSi matrices did not increase after day 3, but with TiO2 matrices the amount increased for 7 days. The prolonged period of proliferation with TiO2 scaffolds resulted in a delay in alkaline phosphatase induction. However, osteocalcin incorporation into extracellular matrix by day 14 was greater with TiO2 scaffolds than with cpTi scaffolds. Calcium deposition was also greater with TiO2-coated substrates than with uncoated substrates. With the TiSi scaffolds osteocalcin production and mineralization were lower than with the cpTi scaffolds. The current study confirms our previous findings that titanium fiber mesh supports attachment, growth, and differentiation of rat bone marrow stromal cells. Furthermore, the osteogenic capacities of cell-scaffold constructs under cell culture conditions were increased with a sol-gel-derived titania coating, but not with a titania-silica coating.