摘要:
为了模拟天然骨组织的结构和成分, 以羟基磷灰石(HA)为钙磷源, 以壳聚糖(CS)为大分子基质材料, 在酸性环境中形成均相溶液, 通过Sol-gel相转变矿化方法和陈化处理, 原位构建了纳米HA/CS复合多孔支架材料, 研究了共沉积时体系的pH值和陈化时间对支架压缩强度、晶相组成及形貌等的影响。结果表明体系pH为10和11时, 支架的力学强度远高于未矿化壳聚糖支架强度, 但是随着体系pH的升高强度逐渐下降。XRD分析结果表明陈化处理有利于磷酸钙盐向HA转化, 随着陈化时间的延长, 纳米HA沿c轴择优生长。SEM观察显示支架材料具有相互贯穿的多孔结构, 纳米级的短棒状或颗粒状HA晶体颗粒均匀分散在孔壁上, 随着陈化处理以及陈化时间的延长, 形成致密的纳米无机/有机均匀复合体。这种快速深度矿化方法为骨支架材料的制备提供了新思路。
Abstract:
To mimic the components and structure of the natural bone, chitosan (CS) and hydroxyapatite (HA) were selected as the macromolecule and the source of the calcium phosphate, respectively. The raw materials were dissolved in an acid solvent to form homogeneous solution, and then underwent sol-gel phase transition and aging procedure to prepare nano-HA/CS porous composite scaffolds in situ. The effects of aging time and pH value on the composition, micromorphology and compressive strength of the HA/CS composites were studied. The results show that the compressive strength and modulus of the scaffolds decrease obviously with the increase of the pH value, and the compressive strength is higher than pure CS scaffolds when the pH is 10 and 11. XRD results indicate that the transition of phosphorus calcium to HA can be impelled with the aging treatment, and the growth of HA crystallites orients along the c- axis in the crystal structure. SEM results reveal that the scaffolds possess inter-connected porous structure, and the rod-like or grainy nano-hydroxyapatite crystal particles disperse uniformly in the scaffolds, which formed homogeneous dense organic/inorganic composites. This kind of fast and deep mineralization method for preparation of bone scaffold provides a new way of thinking.
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