College of Materials Science and Engineering, Sichuan University, Chengdu 610064 China...

Ultrafine β-tricalcium phosphate (β-TCP) powders with good crystalline structure were produced by a new wet process. Through bone tissue engineering approach, porous β-TCP ceramic was combined with recombined human bone morphogenetic proteins-2 (rhBMP-2) to develop a novel composite material. Osteogenesis capacity of the composite was investigated intramuscularly in rat with histological analyses and SEM examination. Pure β-TCP porous ceramic was investigated as the control. Results show that the composite materials possess good biocompatibility, biodegradation and strong osteogenesis capacity through inductive process after implantation. Material degradation began from 2 weeks post-implantation accompanying with the changing of pore structure, with the enwrapping and separation of materials by hyperplatic mesenchymal cells and fibroblast, and with the phagocytose reaction of multinucleated giant cells. Early in 72 h, immature cartilage could be found within novel composite; mature lamellar bone was induced to generate after 3 weeks. With strong osteoinduction capacity and controllable biodegradation, the novel rhBMP-2/β-TCP porous ceramic is expected to be a promising bone grafting substitute for bone tissue engineering.