| Most bone tissue-engineering composites are composed of at least two basic components: seeding-cells (or factors) and scaffold materials. The cellular component is necessary for the generation of matrix and is responsible for the long-term maintenance of this matrix. Bone morphogenetic protein can induce mensenchymal cells to differentiate to cartilage and bone-cells in separate place. The scaffold materials provide mechanical stability and maintain a three-dimensional space for the formation of new bone tissue with appropriate structure. So it is pivotal to the select seeding-cells and the scaffold materials for bone tissue engineering.A new preparing process of β-tricalcium phosphate( β-TCP), a -TCP ultrafine powders and porous P -TCP bioactive ceramics has been studied in the present thesis. High-purity and ultrafine CaCO3 powders were mixed to slurry with water and phosphoric acid is diluted to solution. The amount of CaCO3 and H3PO4 was added according to Ca/P=1.50. Then CaCO3 slurry was poured into phosphoric acid solution quickly in normal atmospheric temperature, stirring phosphoric acid solution and ultrasonic agitation. Finally, high-purity and ultrafine Ca3 (PO4) 2nH2O was synthesized. The β -TCP ultrafine powder was prepared by calcining Ca3 (PO4) anHaO at 1170℃. The a -TCP ultrafine powder was prepared by calcining Ca3 (PO4) anH2O at 1230℃. Using PVA solution as sticking agent and columnar fatty acid as making pore agent, the porousβ-tricacium phosphate bioactiveceramics were prepared by sintering process at 1170℃. The ceramics have cross-columnar holes inside and higher strength, which adsorb and release the bone morphogenetic protein (BMP) easily. The ceramics have good dissolvable ability and offer abundant Ca and P elements for the new bone. According to adjusting hole construction and porosity of the ceramics, the strength and dissolvable rate of the ceramics can be controlled.The high-purity ultrafine α -TCP powder produced by the new process hasexcellent setting property and hydrating property. The assist agents are high-purity ultrafine DCP and CaO self-produced. Mol ratio is α-TCP: DCP: CaO -0.95: 0.025: 0.025. The mixture powders were mixed with 0.25M NaH2PO4/Na2HP04. Their initial setting time is about 7 min, the final setting time is about 35 min. The compressive strength reached 35 MPa after 5 days immersed in Hank's solution. It was enough for repairing skull defects. By using Urist method , a partly purified active BMP was extracted from one-year-old steers long tubular cortical bone. BMP, α -TCP powders and assist agents were mixed with liquid phase. Three kinds of materials which were BMP/α-TCP composites of containing 1%, 2%BMP and a -TCP cement alone were separately used to repair large skull defects of adult rabbits. After operating 4 weeks, osteogenesis and a few calcium sediments were observed in two BMP/ α-TCP composites. This situation was enhanced after operating 8 weeks. Bone tissue was more mature and bone union was formed after operating 16 weeks. By contrast with BMP/α-TCP composites , osteogenesis and calcium sediments were lower in a -TCP cements alone and bone union could not be formed after operating 16 weeks. The BMP/α-TCP-B cement was the most potent activator of osteogenesis. However, the resorption of materials in a -TCP cement alone was almost the same as BMP/α-TCP(B).Porous 3 -tricalcium phosphate (β-TCP) was compound with recombinant human bone morphogenetic proteins-2 (rhBMP-2). The rhBMP/β -TCP composite has been obtained. The composites were implanted into the muscles of the thigh of mice. The ability of bone induction and degradation of the materials has beenobserved. The immature cartilage was found affter 72 hours, the mature cartilageafter 1 week, the wave bones after 2 weeks and the laminar bones with bone marrow after 4 weeks. No bone or cartilage was found in control group. The early stage of degradation was found, which was represented by the phenomenon of fibrous tissues and mensenchymal c...
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