Cytocompatible 3D chitosan/hydroxyapatite composites endowed with antibacterial properties: toward a self-sterilized bone tissue engineering scaffold

Bone tissue scaffolds based on bioactive polymer-hydroxyapatite composites have caused infections that seriously limit their extended application. In this study, we proposed a practical ion substitution method to synthesize in situ silver phosphate on the surface of a two-level, three-dimensional chitosan/nano-hydroxyapatite scaffold. A release test of silver ions in a phosphate buffered saline (PBS) solution was performed to demonstrate that silver ions were released continuously from the silver phosphate during the initial 6 days of the study. The antibacterial property and cytocompatibility of the scaffolds treated with different concentrations of silver nitrate solution were assessed by in vitro assays with Escherichia coli and MC3T3-E1, respectively. The ability of the silver-containing scaffolds to induce bacteriostasis was confirmed by the inhibition zone (15 mm) and high bactericidal rate (>99%). Cell proliferation, morphology and the alkaline phosphatase activity of MC3T3-E1 cultured on the scaffold with low silver phosphate contents were comparable with those cultured on control samples.