| Since the large bone defect cases can not self heal, the bone graft is needed to auxiliary healing. Bone tissue engineering research is mainly concentrated in two aspects. One is bone induction, a porous biodegradable scaffold was used to fill the defect, which has the ability of bone conduction and bone induction, can cause the osteoblast and otther cells move into and spread on the scaffold. The other is cell migration, the autologous osteoblast and osteoblastoma in the sacffold play a important role in defect healing, the migration of osteoblast is contribute to tissue ingrowth and the formation of the extracellular matrix. The scaffold materials for bone tissue engineering need to fulfill a few basic requirements, including biocompatibility, three-dimensional (3D) porous structure, biodegradability, favorable material/cell interface and mechanical properties. Furthermore, for in vivo bone tissue engineering, the surface properties of scaffolds (chemical composition, surface microstructure) also play critical roles.In this study, HA porous scaffolds were prepared by three methods, then the macro and micro porous structures of the scaffold were characterized by stereomicroscope and SEM. Used dog as an experimental mode, the HA spherule scaffolds were implanted in enterocoelia to study the biological properties of the material. Observation of material deformation, vaseularized and ossification were characterized by histotomy, and the mechanical properties were also characterized, then the implant were used to repair the bone defect. We improved the method of hard tissue slicing for research of bone tissue engineering of bioceramic materials, prepared the better thin layer histologic dyeing specimens. The mechanical properties of HA scaffolds is the main rejection for applied in bone repair.The main conclusions were obtained as follows:· The HA scaffold has regular pore structure, suitable porosity and good mechanical properties, and HA spherule scaffolds were implanted in enterocoelia to study the biological properties of tissue engineered bone. · We improved the hard biopsy technology to make a better analysis of the interaction between materials and tissues. Traditional hard biopsy technology had the following defects: when the ceramic specimens were cut to very thin, it can hardly keep the integrity, and were easy to take off when dyeing. The improved technology overcame the defect that it may destroy organization, when we use the histologic detection technology to deal with the biological ceramic materials. It fundamentally solved the defects such as dyeing of take off and dye absorption, so as to got the integral and clear histologic dyeing specimens.· The compressive property of the tissue engineered bone built by scaffolds was increased significantly along with the increase of the implant time. The porous scaffolds had the better compressive property compared with the density ones. That may be due to the porous surface was more advantageous to the protein absorption and cell proliferation, and induct the tissue extended into the scaffolds, induct the formation of the bone eventually.· The mechanical property of defect bone healed with the tissue engineered bone was increased along with the increase of the healing time, the influence factors of the healed bone mechanical property included the implant time and the in suit repair time.We found that the mechanical property of the healed bone were almost close to normal bone along with the increase of the healing time. The materials and the bone were combined well, bone tissue conduction were well done, the interface of material-bone were indistinct, and the materials were degradation transformation unceasingly. |
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