Regulation of TiO2 nanoarrays on titanium implants for enhanced osteogenic activity and immunomodulation

The surface topography of implants plays a major role in osteogenesis and immunomodulation. In this study, three types of TiO 2 nanoarrays including nanorod arrays with a diameter of 45 nm (TiO 2 -N), nanorod arrays with a diameter of 60 nm (TiO 2 -N N), and nanocone arrays (TiO 2 -NW) are prepared on titanium and the behavior of bone marrow stromal cells (BMSCs) and polarization of macrophages are studied. Compared to the planar titanium control, TiO 2 nanoarrays facilitate osteogenesis of BMSCs and stimulate the pro-healing M2 phenotype. However, adhesion, spreading, proliferation, and osteogenic differentiation of BMSCs are more pronounced on TiO 2 -N N than both TiO 2 -N and TiO 2 -NW. TiO 2 -NN also produces the best immune microenvironment, while TiO 2 -NW is more favorable than TiO 2 -NN from the viewpoint of cell adhesion and spreading of osteoblasts.