Surface Oxygen Vacancies of Rutile Nanorods Accelerate Biomineralization

Titanium dioxide (TiO₂) materials have been widely used in biomedical applications of bone tissue engineering. However, the mechanism underlying the induced biomineralization onto the TiO₂ surface still remains elusive. In this study, we demonstrated that the surface oxygen vacancy defects of rutile nanorods could be gradually eliminated by the regularly used annealing treatment, which restrained the heterogeneous nucleation of hydroxyapatite (HA) onto rutile nanorods in simulated body fluids (SBFs). Moreover, we also observed that the surface oxygen vacancies upregulated the mineralization of human mesenchymal stromal cells (hMSCs) on rutile TiO₂ nanorod substrates. This work therefore emphasized the importance of subtle changes of surface oxygen vacancy defective features of oxidic biomaterials during the regularly used annealing treatment on their bioactive performances and provided new insights into the fundamental understanding of interactions of materials with the biological environment.