In vitro evaluation of the biological compatibility and antibacterial activity of a bone substitute material consisting of silver-doped hydroxyapatite and Bio-Oss®.

This study evaluated biological compatibility and antibacterial activity of a bone substitute material consisting of silver-doped hydroxyapatite (AgHA) and Bio-Oss® with different mixture ratios in vitro and investigated its antibacterial mechanism. AgHA was synthesized by a chemical precipitation method. After characterization, AgHA was mixed with Bio-Oss® at three ratios: 1:1, 1:2, and 1:4 by weight. Then, Porphyromonas gingivalis (Pg) and Fusobacterium nucleatum (Fn) were used to test the antibacterial activity of the mixture. Human periodontal ligament fibroblasts and rat bone marrow stromal cells were selected for cytocompatibility experiments. According to results, the peak value of the size of the AgHA was concentrated in the 100-200 nm range, and AgHA particles consisted of short rods. It was confirmed that the structure of AgHA was similar to that of standard hydroxyapatite. All three mixture ratios exhibited obvious antimicrobial properties, which increased with increasing AgHA. According to the effects on the expression of bacterial virulence genes, groups 1:1 and 1:2 both negatively affected Pg and Fn more significantly than group 1:4. Cytotoxicity experiments showed that 1:1 caused little cytotoxicity, while groups 1:2 and 1:4 exerted no significant cytotoxicity. Considering its biological compatibility and antibacterial activity, group 1:2 is the most recommended.