Promoting osseointegration of titanium implants through magnesium- and strontium-doped hierarchically structured coating
Jie Zhang, Bianyun Cai, Peijie Tan, Min Wang, Bassam Abotaleb, Songsong Zhu, Nan Jiang
Abstract
This study aimed to investigate the effect of magnesium (Mg) and strontium (Sr) surface modification on osseointegration of titanium (Ti) implants with a hierarchically structured coating. Mg- and Sr-doped hierarchical surface coating has been fabricated on Ti implant through the hydrothermal method. Scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectrometer (EDS), inductively coupled plasma/optical emission spectroscopy (ICP-OES) and contact-angle measurement have been applied to characterize the surface coating. The biocompatibility and osseointegration of Ti implants with Mg- and Sr-dropped hierarchical coating have been assessed in vivo using a rat tibia implantation model. The proposed mechanism that improves osteointegration of Mg- and Sr-doped coating Ti implant has been evaluated by culturing rat bone marrow stromal cells (BMSCs) alone or co-culturing Schwann cells (SCs) and BMSCs on the coating surfaces. Our results proved that both Mg- and Sr-doped hierarchical coating could promote osseointegration with Mg exerted a stronger effect in vivo. The in vitro outcomes showed that Mg-doped coating enhances BMSCs adhesion, while the Sr-doped surface promotes osteogenic differentiation of BMSCs. Furthermore, when BMSCs were cultured with SCs, Mg-dropped surfaces accelerated not only the adhesion but also osteogenic differentiation of BMSCs. Conclusively, the hierarchical surface coating with trace element modification can provide a strong guarantee for endosseous applications of titanium (Ti) implants, and Mg-doped hierarchical coating is more effective in promoting osseointegration than Sr modification.