Physical properties and cytotoxicity of surface-modified bovine bone-based hydroxyapatite/poly(lactic acid) composites

This study was a preliminary observation for a potential use of the bovine bone-based hydroxyapatite (b-HA)/poly(lactic acid) (PLA) composite as a biomaterial. SEM micrographs, XRD pattern, and FTIR spectrum of calcined bovine bone revealed that the obtained powder was in a form of crystalline carbonated HA, and highly agglomerated. The surface of HA powder was modified with either 3-aminopropyltriethoxysilane (APES) or 3-methacryloxypropyltrimethoxysilane (MPTS) in order to enhance the compatibility between b-HA and PLA matrix. TGA and GPC results revealed that the incorporation of silane-treated HA into the PLA matrix significantly increased thermal stability of the composites and decreased the thermal degradation of PLA chains. SEM micrographs revealed that modification of HA with APES or MPTS eased dispersion of HA in PLA matrix and enhanced interfacial adhesion between both phases. Therefore, the mechanical properties of silane treated HA/PLA composites were improved as compared with those of b-HA/PLA composites. In addition, in vitro cytotoxicity tests indicated that the extracts from all HA/PLA composites had no toxicity to human osteoblast cell.