Effects of Surface Wettability of Titanium Oxide Coatings on Osteoimmunomodulatory Properties

Titanium and its alloys have been widely used as hard tissue implants due to their excellent mechanical properties and biocompatibilities. However, the lack of biological activity on its surface and the inflammatory reaction after implantation can easily lead to unsatisfactory osseointegration. In this work, the wettability of titanium oxide coatings was modulated by annealing in different atmospheres, and the effects of surface wettability on polarization of macrophages and osteogenic differentiation of mBMSCs were studied. The results showed that, compared to the hydrophilic titanium oxide coating (similar to 10 degrees, PEO-A), the titanium oxide coating with contact angle about 90 degrees (PEO-A-V) inhibited the polarization of macrophages towards M1 pro-inflammatory direction under the mono-culture condition. However, under the co-culture condition, the titanium oxide coating with contact angle about 90 degrees promoted macrophage polarization towards M2 and significantly upregulated gene expressions of osteogenic markers related to mBMSCs, indicating better immunomodulatory effects on osteogenic differentiation of mBMSCs.