In vitro evaluation of Ag-containing calcium phosphates: Effectiveness of Ag-incorporated β-tricalcium phosphate

Development of bioceramics with antibacterial activity and without cytotoxicity would be beneficial for preventing infection associated with implants. This study aimed to capitalize on the antibacterial properties of silver (Ag) incorporated in or coexisting in metallic form with calcium phosphates (CaPs). The in vitro dissolution behavior, antibacterial activity, and cytotoxicity of Ag-containing CaPs with different phase fractions of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) were evaluated. The antibacterial activity of Ag-containing CaPs depended on the main phase of CaP, the chemical state of Ag, and the amount of incorporated Ag. Superior antibacterial activity was obtained from sustained release of Ag ions through continuous dissolution of Ag-incorporated β-TCP compared to that obtained for HA coexisting with metallic Ag particles. Ag-containing CaPs did not exhibit any toxic effect on V79 fibroblasts. Thus, these results demonstrated the effectiveness of Ag-incorporated β-TCP in preventing infection, with respect to long-term applications.