Effect of Silver Doped-hydroxyapatite on Bacterial and Osteoblast Responses

INTRODUCTION: The goal of this study is to investigate the role of silver (Ag)-doped HA coatings on in vitro bacteria adhesion and bone cell activity. METHODS: Commercially pure titanium (Ti) disks were cleaned using the ASTM F86-91 protocol. A 1% Ag-doped HA sol was synthesized and was spin-coated on Ti disks, dried, followed by a heat treatment at 650°C for 3 hours. Non-Ag-doped HA and Ti disks were used as controls. Adhesion of Staphylococcus epidermidis and Staphylococcus aureus was determined by measuring their colony forming units (CFU) on the different surfaces, whereas toxicity profiles were determined after seeding human embryonic palatal mesenchyme cells, an osteoblast precursor cell line and measured using the MultiTox-Fluor Multiplex Cytotoxicity Assay. Differences in CFU and toxicity were statistically compared using the ANOVA test (p < 0.05). RESULTS: S. aureu and S. epidermidis on Ag-doped HA surfaces were observed to be significantly reduced when compared to HA and Ti surfaces (P<0.05). The toxicity profiles of osteoblast precursor cells indicated no significant difference in cell toxicity between the Ag-doped HA, HA, and Ti surfaces. Additionally assays measuring Caspase 3/7 activity, a key effector of apoptosis in mammalian cells, indicated no significant difference in viability between cells cultured on all test surfaces. CONCLUSIONS: It was concluded that the 1% Ag-doping on HA surfaces were non-toxic to osteoblast cells. Additionally, it was also concluded that the 1% Ag doping was effective in reducing bacterial adhesion.