【作者】 李俊杰；

【导师】 姚康德；

【作者基本信息】 天津大学 ， 材料学， 2007， 硕士

【摘要】 人工合成骨替代材料对骨缺损治疗至关重要,美国食品和药物管理局（FDA）至今没有批准结合有细胞或生长因子的骨组织工程用装置。天然骨是由纳米羟基磷灰石和胶原纤维组成的有机/无机复合物,因此,形成纳米羟基磷灰石/高聚物复合材料对于提供良好的生物相容性以及骨组织的整体结合具有非常重要的作用。本文从仿生的角度出发,将壳聚糖-明胶网络膜（CG）浸泡于Ca（NO₃）₂-Na₃PO₄的Tris缓冲溶液中在其表面原位沉积形成纳米羟基磷灰石（nHA）,通过反射红外光谱（ATR-FTIR）、X射线衍射（XRD）以及热失重分析研究nHA晶体和CG膜之间的相互作用,同时通过XRD及投射电镜考察了影响nHA晶体粒径大小的因素,如复合物中壳聚糖-明胶的比例,钙离子浓度和反应温度。结果发现,羧基、羰基和氨基在HA的形成过程中起非常重要的作用,nHA晶体的平均粒径随着明胶含量增加和钙离子浓度的减小而降低,同时发现在50℃以下时温度对粒径大小基本没有影响（17.2-19.2 nm之间）,但是当温度增加到70℃时粒径迅速增加到52.3nm。细胞相容性是生物材料必须具备的性能之一,本文在制备nHCG复合材料的基础上,研究了胃癌细胞以及骨髓基质干细胞（MSCs）在nHCG复合膜以及微米羟基磷灰石/壳聚糖-明胶网络复合膜（mHCG）上的细胞行为,实验表明,nHCG复合材料较mHCG复合材料更能抑制癌细胞的生长且随着复合材料中nHA含量的增加抑制作用越强;另一方面,nHCG能够促进MSC细胞的粘附与增值,同时能够促进其诱导分化表现出较高的碱性磷酸酶活性。利用相分离技术制备了CG网络支架,并在支架表面原位沉积nHA晶体,形成nHCG支架。结果发现nHCG支架材料具有较高的孔隙率和合适的孔径大小,同时具有较强的力学性能。在模拟体液中,nHCG支架对其所处环境的pH值影响较小,溶胀度也较小。在此基础上,构造了小型猪成骨细胞/nHCG多孔支架结构物,从材料制备科学以及组织工程学的角度张开了基础研究。更多还原

【Abstract】 The development of biomaterials as bone substitutes is of clinical significance for the repair of large bony defects. According to the Food and Drug Administration （FDA）, at present there are not approved orthopaedic devices that incorporate tissue-derived components such as cell and /or growth factors.Form the point of view of biomimetic, in this work, nHA crystalline was formed in-situ on the surface of chitosan–gelatin （CG） network films in tris-buffer solution containing Ca（NO₃）₂-Na₃PO₄. The interaction between CG network film and nHA crystalline were studided using the diffuse reflectance FT-IR （ATR-FTIR）, thermal analysis （TGA） and X-ray diffraction analysis （XRD）, and the influence the nHA size factors, e.g. the ratio of chitosan （CS） and gelatin （Gel）, concentration of calcium ions and reaction temperature, were elucidated by XRD and transmission electron microscope （TEM）. Results suggested that carboxyl groups, COO- and amino groups play crucial roles for HA formatting on the surface of CG network films and the average size of nHA crystalline decreasing with enhancing Gel content and increase with the increasing calcium and phosphate concentration, and when the reaction temperature below 50℃the nHA crystalline size is almost fixedness （range from 17.2 to 19.2 nm） but when the temperature arrived at 70℃it increase to 52.3 nm.Stomach carcinoma cells and marrow mesenchymal stem cells （MSCs） were seeded on the surface of nHCG and mHCG network films in order to study the different cells behaver on the two composites. Results indicated that the nHCG can inhibit the stomach carcinoma cell attachment and proliferation, and the inhibit effect become more obvious with the increasing of nano-hydroxyapatite crystalline content; In other hand, MSCs maintained higher attachment ability on the surface of nHCG network films than that on the mHCG network films and cell viability, and abilities of MSCs attachment and proliferation enhancing with the increasing nHA crystalline content, nHCG can improve osteogenic differentiation comparison to the on the surface of mHCG network films.The CG macroporous scaffolds were fabricated through freeze-dry technique, nHA crystalline formed on the surface of CG surface of CG scaffold in situ, the microstructures of scaffolds were characterized by FT-IR and SEM. The results indicated that the freeze-drying temperature had great impact on the formation of nHA on the scaffold walls, the nHCG scaffold have very high porosity and the compressive strength also greatly had been improved with enhancing nHA content; in simulated body （SBF）, the nHCG network scaffold swell a little and have a small influence on the pH of a aqueous environment. Minitype pig osteoblast cells were seeded into nHCG scaffolds and results revealed that he composite scaffolds had good compatibility and it is potential biomaterials for bone tissue engineering.更多还原