Bioactivity of a Novel Nano composite of Hydroxyapatite and Chitosan-Phosphorylated Chitosan Polyelectrolyte Complex

The bioactivity of a novel composite of carbonate-containing low-crystallinity nanoparticle hydroxyapatite (HA) and a chitosan-phosphorylated chitosan polyelectrolyte complex (PEC) was evaluated in vitro and in vivo. The HA-PEC nanocomposite with complicated porous structure was prepared by a biomimetic method. An acidic chitosan (polycation) solution containing calcium and phosphate ions (6 mM Ca2+, Ca/P : 1.67) was added into phosphorylated chitosan ( polyanion) solution; the formation of PEC and the controlled HA crystal growth were co-organized in alkaline solution. The material was co-cultured with rat osteoblasts in vitro, and implanted into rabbit femur marrow cavities. The results indicate that the PEC-HA composite promoted osteoblast adhesion, morphology, proliferation, and differentiation in vitro; the bone tissue response to the material histologically showed that it was bioactive, as well as biodegradable. The HA-PEC composite shows promise as a bone-repair material.