Cellular responses to nanoscale substrate topography of TiO2 nanotube arrays: cell morphology and adhesion.

Nanotopographical features can be beneficial in augmenting cell functions and increasing osteogenic potential. However, the relationships between surface topographies and biological responses are difficult to establish due to the difficulty in controlling the surface topographical features at a low-nanometre scale. Herein, we report the fabrication of well-defined controllable titanium dioxide (TiO₂) nanotube arrays with a wide range of pore sizes, 30-175 nm in diameter, and use of the electrochemical anodization method to assess the effect of surface nanotopographies on cell morphology and adhesion. The results show that TiO₂ nanotube arrays with pore sizes of 30 and 80 nm allowed for cell spreading of bone marrow-derived mesenchymal stem cells with increased cell area coverage. Additionally, cell adhesion was significantly enhanced by controlled nanotopographies of TiO₂ nanotube arrays with 80 nm pore size. Our results demonstrate that surface modification at the nano-scale level with size tunability under controlled chemical/physical properties and culture conditions can greatly impact cell responses. These findings point to a new direction of material design for bone-tissue engineering in orthopaedic applications.