Antibacterial and biological properties of silver-loaded coralline hydroxyapatite

The antibacterial and biological properties of silver-loated coralline hydroxyapatite (Ag-CHA) as a new antibacterial implant material were investigated in this study. Compared to other antibiotic and chemical bactericidal agents, Ag⁺ does not bring bacterial resistance to drugs and has less toxicity. The porous CHA was formed by hydrothermal exchange, then Ag⁺ was loated onto CHA through ion exchange and adsorption. The microstructure and composition of Ag-CHA were characterized by scanning electron microscopy (SEM), Rutherford backscattering spectrometry (RBS), and energy dispersive spectrometry (EDS). Antibacterial activity of Ag-CHA on the clinical strains of Escherichia coli (E. Coli) and Staphylococcus aureus (S. Aureus) was evaluated by the flat plate diffusion method. The antibacterial activity of Ag-CHA was found to be correlated with the concentration of Ag⁺ in a dose-dependent manner, which indicated that the optimal antibacterial and biocompatible effects of Ag-CHA could be obtained with Ag⁺ concentrations from 5×10⁻⁵ to 1×10⁻⁴ mol/L.