TiO₂ Nanotube Surfaces: 15 nm—An Optimal Length Scale of Surface Topography for Cell Adhesion and Differentiation

Using aligned TiO2 nanotubes with different diameters in the range between 15 and 100 nm synthesized on titanium by an electrochemical approach, it is shown that 15 nm is a universal surface geometric constant that promotes cell adhesion, proliferation, migration, and differentiation of different cell types (such as mesenchymal stem cells and hematopoietic stem cells; see image).