Evaluation of antibacterial activity and cytocompatibility of α-TCP based bone cements with silver-doped hydroxyapatite and CaCO3

The implant-related infections are a severe problem in orthopedic surgery. In this work, bone cements based on alpha-TCP, silver doped hydroxyapatite and calcite were examined. Developed bioactive materials revealed good surgical handiness and appropriate setting times allowing for their application. In order to assess antibacterial properties, two independent experiments (test imitating in vivo conditions and test of cumulative extraction) were used. It was found that bone cement matrix do not impede the Ag+ release from the Ag-HA agglomerates. Materials showed mild antibacterial activity which depended on the kind of bacterial strain and the type of test. Presence of silver in the tested materials increased the antibacterial activity in the extracts only for E. coil strain and the effect was transient. In the case of Gram-positive strains (S. aureus and S. epidermidis), antibacterial activity was most probably connected with the properties of cement material, not with the content of silver. Observed reduction of osteoblast viability in vitro resulted from the synergic effect: decrease in concentrations of Ca2+, Mg2+, and PO43- ions in the culture medium and the presence of silver ions.