I型胶原/氧化糖胺聚糖自交联体系的构建及构-效关系

As the vital components in extracellular matrix (ECM), Type Ι collagen and glycosaminoglycans are the most widely used scaffold materials due to their good biocompatibility and weak antigenicity. However, the mechanical property and thermal stability of scaffolds derived from nature ECM components are relatively weak. Although exogenous chemical crosslinking is adopted to improve the corresponding performance, the biological properties of this kind of scaffold decrease as a result. Therefore it is expected that periodate-oxidized glycosaminoglycans(OGAG) having a series of molecular weight and degree of oxidation could be prepared controllably and accurately. Then the stability and mechanical properties as well as the biological performance could be improved by self-crosslinking of OGAG and collagen, without using any toxic crosslinking agents. Based on the systematic studies of the interactions between collagen and OGAG in homogeneous blends, the effects of GAG structure, oxidation degree and amounts of OGAG on the aggregation structure of collagen and rheological property of solution are investigated. Furthermore the structure-activity relationships between the microstructure of collagen/OGAG solution and various macro-performances of scaffolds could be obtained, which are useful for controllable preparation of self-crosslinked collagen/OGAG scaffolds. In addition the roles of GAG played during the self-assembly process of collagen could be confirmed by comparing the influences of GAG and OGAG on collagen self-assembling properties.

I型胶原和糖胺聚糖是细胞外基质（ECM）重要组分，因其生物相容性好、抗原性低，均被广泛用于制备支架材料。纯ECM组分构建的支架材料机械性能和热稳定性较低，虽引入外源化学交联剂可弥补这一缺陷，但以损害材料生物学性能为代价。针对此问题，本项目拟优化制备一系列分子量和氧化度的氧化糖胺聚糖(OGAG)，并用其交联改性胶原，优化支架材料生物学性能的同时改善其机械性能和稳定性。在系统研究均一胶原/OGAG自交联溶液中两者相互作用的前提下，主要探究GAG硫酸化位点和硫酸化程度、OGAG氧化度和用量对胶原聚集态结构和改性溶液流变学性能的影响，进而获得胶原/OGAG溶液微观结构与复合生物材料热稳定性、流体力学性质等宏观性能间的构-效关系，指导胶原/OGAG自交联支架材料的可控制备。此外，拟通过分析OGAG和GAG对胶原自组装性能影响的差异，明确GAG在胶原分子自组装过程中发挥的作用。

胶原蛋白虽存在力学性能较差、热稳定性偏低、遇水易溶胀、体内酶降解速率过快等缺点，仍是制备支架材料广泛应用的原材料之一。为优化胶原基生物材料的综合性能，本项目以天然多糖为原料，制备了一系列无毒、氧化度和分子量可调的新型交联剂，使改性胶原材料满足体内复杂微环境对支架材料的需求，且不引入外源交联剂，对组织工程领域具有重要的理论参考价值。.主要研究内容如下：氧化多糖交联剂的可控制备及性能表征；氧化多糖对胶原聚集态结构、自组装性能及流变性能的影响；氧化多糖改性胶原材料的制备及性能研究；水貂皮含蛋白废弃物的资源化利用。.本研究已实现高得率、分子量和氧化度可调的天然氧化多糖交联剂的精准制备。将制得的氧化多糖用于改性胶原时，主要考虑氧化多糖种类、用量、氧化度、分子量对改性胶原微观结构和宏观性能的影响。氧化多糖主要是通过新生成醛基的C=O键与胶原侧链的自由氨基反应，生成席夫碱结构，使胶原的内源荧光猝灭，进而促进了胶原分子间的聚集，增加胶原基生物材料的稳定性；此外，氧化多糖分子中存在部分由于氧化作用而断链降解的多糖物质，这部分多糖与胶原分子间存在氢键或静电相互作用，有利于优化改性胶原的生物学性能。.采用两种体系研究氧化多糖改性对体外生理条件下胶原自组装性能的影响。第一种反应体系中氧化多糖交联改性与胶原自组装同时进行。第二种反应体系中，氧化多糖先对胶原进行交联改性，后再进行胶原自组装。两种体系中交联改性和胶原自组装行为处于竞争关系，氧化多糖对胶原自组装的影响各异，制备基于胶原自组装行为的生物材料时需根据目标要求，综合考虑选择适合的氧化多糖种类及反应体系。.氧化多糖改性胶原均呈现典型的“剪切变稀”行为；氧化多糖改性可提高胶原的粘度值，且提高幅度与交联程度正相关。改性后胶原弹性特征占优势，触变性能与氧化多糖种类、用量和氧化度相关。.用环保的过氧化氢处理水貂皮含蛋白废弃物，为其资源化利用提供依据。.