Influence of sterilization methods on cell behavior and functionality of osteoblasts cultured on TiO2 nanotubes

The adhesion, proliferation and osteogenic functionality of osteoblasts cultured on TiO2 nanotubes in response to different sterilisation methods (dry autoclaving vs. wet autoclaving) were investigated. Various sizes (30-100 nm diameter) of TiO2 nanotubes were prepared on titanium substrates by anodisation, sterilised nanotubes under different conditions, and seeded osteoblast cells onto the nanotube surfaces with two different cell seeding densities (10000 vs. 50000 cells/well in 12-culture well). The results indicated that the adhesion, proliferation and alkaline phosphatase activity of the osteoblasts cultured on only the larger 70 and 100 nm TiO2 nanotube arrays were changed by the different sterilisation conditions at a low cell seeding density. However, with a higher cell seeding density (50000 cells/well in 12-cell culture well), the results revealed no significant difference between altered nanotube geometry, 30-100 nm diameter, nor sterilisation methods. It was also revealed that the nano-features of proteins adhered on nanotubular TiO2 morphology were altered by the sterilisation method. The protein adhesion effect, in combination with the cell density of osteoblasts seeded onto such TiO2 nanotube surfaces, had profound effects on cell behaviour. This study showed that these are some of the important in-vitro culture factors that need to be taken into consideration, and the TiO2 nanotube diameter plays an important role in the improvement of cell behaviour and functionality.