Osteogenic and anti-inflammatory effects of SLA titanium substrates doped with chitosan-stabilized selenium nanoparticles via a covalent coupling strategy

Osseointegration is a prerequisite for the function of dental implants, and macrophage-dominated immune responses triggered by implantation determine the outcome of ultimate bone healing mediated by osteogenic cells. The present study aimed to develop a modified titanium (Ti) surface by covalently immobilizing chitosan-stabilized selenium nanoparticles (CS-SeNPs) to sandblasted, large grit, and acid-etched (SLA) Ti substrates and further explore its surface characteristics as well as osteogenic and anti-inflammatory activities in vitro. CS-SeNPs were successfully prepared by chemical synthesis and characterized their morphology, elemental composition, particle size, and Zeta potential. Subsequently, three different concentrations of CS-SeNPs were loaded to SLA Ti substrates (Ti-Se1, Ti-Se5, and Ti-Se10) using a covalent coupling strategy, and the SLA Ti surface (Ti-SLA) was used as a control. Scanning electron microscopy images revealed different amounts of CS-SeNPs, and the roughness and wettability of Ti surfaces were less susceptible to Ti substrate pretreatment and CS-SeNP immobilization. Besides, X-ray photoelectron spectroscopy analysis showed that CS-SeNPs were successfully anchored to Ti surfaces. The results of in vitro study showed that the four as-prepared Ti surfaces exhibited good biocompatibility, with Ti-Se1 and Ti-Se5 groups showing enhanced adhesion and differentiation of MC3T3-E1 cells compared with the Ti-SLA group. In addition, Ti-Se1, Ti-Se5, and Ti-Se10 surfaces modulated the secretion of pro-/anti-inflammatory cytokines by inhibiting the nuclear factor kappa B pathway in Raw 264.7 cells. In conclusion, doping SLA Ti substrates with a modest amount of CS-SeNPs (1-5 mM) may be a promising strategy to improve the osteogenic and anti-inflammatory activities of Ti implants.