Fabrication of silver and strontium co-loaded chitosan–gelatin nanocomposite coatings with balanced antibacterial and osteogenic properties

To impart balanced antibacterial and osteogenic properties to titanium substrates, we prepared silver (Ag) and strontium (Sr) co-loaded chitosan–gelatin (CSG) coatings by dual-sourced electrophoretic deposition method, producing a series of Ag/Sr-CSG-modified implants. Physicochemical study confirmed that both Ag and Sr ions were deposited into the coatings successfully. The coatings showed nanostructure, and nanoparticles could be released from the coatings. In vitro antibacterial study showed that all coatings have antibacterial activity, and as the concentration of Ag increased, the corresponding antibacterial ability improved. In the cellular study, promoted osteogenic activity was observed on Ag1/Sr10 and Ag1/Sr50 groups, and this effect of Ag1/Sr50 group was more prominent. In total, the Ag1/Sr50 group had desirable balanced antibacterial and osteogenic properties. This study demonstrated that multiple elements could be co-loaded into CSG coatings with their functional effects preserved, and the antibacterial and osteogenic property could be balanced by adjusting the elements dosage. Graphical abstract