| Developing of a suitable bone graft materials to replace the lost region of bone has been a formidable challenge in orthopaedics and biomaterials research. The materials currently used for bone defect repair, including autografts and allografts as well as synthetic bone substitutes, each has its own shortcomings and difficult to completely meet the need of clinical applications. Bone tissue engineering is a new research area, it provides solutions for generating a new bone tissue with good functional on a large scale, the extracellular matrix (ECM) plays a pivotal role on current bone tissue engineering. Xenogenic bone is easy to obtain and has lower cost than autogeneic or allogeneic bone graft. Therefor, it can be a potential alternatives for bone grafting materials and ECM materials for bone tissue engineering.In this work, a novel processing technique of bone collagen matrix (BCM) has been developed. A series of biological and chemical treatment procedure including defatting, deproteination, partial decalcification, extraction with guanidine-HCl, digestion with trypsin were applied to remove the strongly antigenic proteins and the cellular elements of bovine bone. A wide range of analytical methods was used to investigate the properties of these prepared materials, the cytocompatibility in vitro and the histocompatibility in vivo were studied. The main works and conclusions are included as follows:(1) Bovine bones were obtained from a local slaughterhouse and used in fresh. The bones were stripped of muscle and fat, cleaned of periosteum, demarrowed by pressure with cold water, and stored at -20 C, Bone Collagen Matrix (BCM) was prepared as follows. The precut frozen bone cubes were first thawed in water at 50C, then soaked in dilute NaOH at ambient temperature, followed by a thorough rinse in the running water. They were then refluxed in a mixture of defatting agent, subsequently, the cubes were demineralized by 0.5 mol/1 HC1, and extracted to release noncollagenous proteins with guanidine-HCl, followed by a digestion with trypsin. Finally, the samples were dried at 50 C in vacuo, packed and sterilized by gamma irradiation.Two types BCM involving TBCM and CBCM were prepared as described above, and TBCM-PDLLA composite material was prepared by mergeing PDLLA into TBCM. The tryptophan content of the matrices is used as an indicator of noncollagenous protein, the hydroxyproline content dissolved in the solution is used as an marker of thedistroyed degree of bone collagens, and the analysis of X-ray diffraction (XRD) is used to evaluate the effect on structure of the bone mineral. It is showed that the tryptophan content of two kinds bone cubes near to 2mg/g after extracted with guanidine-HCl for 24h, and less than lmg/g after digested with trypsin. Non-helical telopeptide regions of collagen which are thought to be responsible for the immunogenicity can be removed by digestion with trypsin, and the rigid triple-helical structure keep intact, the mass content of collagen dissolved is less than 1%. XRD analysis of demineralized bone show that both the main component of materials and the crystals of HA had no significant change.(2) The bone specimens were characterized by various of analytical techniques involving infared spectroscopy (FTIR), XRD, differential scanning calorimetry (DSC), energy dispersive X-ray fluorescence (EDXRF), mechanical tests and scanning electron microscopy (SEM), and the composition and the porosity were estimated. The results as follows:(1) The spectroscopy indicated that the major component of the bone blocks was carbonated hydroxyapatite, and the ratio of Ca/P was 1.95~2.03, whereas the major organic component was collagen, the fatty and cellular components were completely eliminated.(2) The results of mechanical tests showed that the tensile Young's modulus value of CBCM was 5956+1259 Mpa, and the compressive Young's modulus value was 12.47+7.64Gpa. Whereas that of TBCM or TBCM-PDLLA was about 90~100 Mpa. These close to that of original native bovine bone respectively. Th...
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