Synthesis of biodegradable hybrid consisting of hydroxyapatite and alginate

Hybrids consisting of hydroxyapatite and biodegradable polymers are attractive materials for bone repair. We recently developed hydroxyapatite- alginate hybrids through a soaking process of alginate modified with 3-aminopropyltriethoxysilane (APES), ethylenediamine (EDA) and CaCl₂ in a solution mimicking body fluid such as SBF, 1.5SBF proposed by Kokubo et al. In this study, biological behavior of the apatite-alginate hybrid fabricated through modification with APES and CaCl₂ were evaluated after implantation in a rat tibia, in comparison with that of alginate gel without hydroxyapatite. The higher degree of calcification was observed for the hydroxyapatite-alginate hybrid than the alginate gel without hydroxyapatite. The hydroxyapatite precipitated on and inside alginate allowed the hybrid to show not only osteoconduction but also suitable biodegradation after implantation in bony defect.