The enhanced bactericidal effect of plasma sprayed zinc-modified calcium silicate coating by the addition of silver

Our previous work demonstrated the antibacterial activity of plasma sprayed zinc-modified calcium silicate coating. To enhance the bactericidal effect, in this paper, silver and zinc co-incorporated calcium silicate coating (ZC0.3-Ag) was fabricated onto Ti-6Al-4V substrate via plasma spraying technology. The coating was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) measurements. Transmission electron microscopy (TEM) showed that the silver nanoparticles 10-100 nm in diameter were randomly distributed in the amorphous matrix after the silver modification. In chemical durability test, the ZC0.3-Ag coating presented improved chemical stability when compared with that of the original and Ag-doped coating. In vitro antibacterial study indicated that the inactivation of bacteria (Staphylococcus aureus and Escherichia coli) on the ZC0.3-Ag coating was significantly enhanced compared to that on the Zn-modified coatings. The enhanced bactericidal activity was attributed to the addition of silver. Cytocompatibility evaluation demonstrated that the ZC0.3-Ag coating surface supported the adhesion and spreading of human mesenchymal stem cells (hMSCs), and no significant cytotoxicity was observed for the coating.