Synergistic effects of titania nanotubes and silicon to enhance the osteogenic activity

In this study, titania nanotubes (TNTs) incorporating silicon (Si) were formed on Ti disks using anodization and electron beam evaporation (EBE) technology to improve the osteogenic activity. The amount of Si was exquisitely adjusted by controlling the duration of EBE to optimize the biofunctionality. As the Si was incorporated, the samples exhibited hydrophilic surfaces. Long lasting and controllable Si release was observed from the EBE-modified samples without cytotoxicity. Moreover, initial cell adhesion, spreading, proliferation and osteogenic differentiation of MC3T3-E1 cells were evaluated. The results showed a notable enhancement of spreading, osteogenesis and differentiation of cells on silicon-coated TNTs (Si-TNTs). In particular, samples with highest amount of silicon (similar to 5.93% Si) displayed greatest augmentation of ALP activity, osteogenic-related gene expression and mineralization compared to the others in the present study. It was indicated that the modification with TNTs and appropriated Si content resulted in enhanced osteoblastic spreading, proliferation and differentiation, and therefore has the potential for future applications in the field of orthopedics.