超临界CO2流体介质中胶原功能化修饰与交联

Aiming at some defeats of collagen, such as poor physical and mechanical properties, low solubility, fast degradation velocity, lacking antibacterial properties, functional chemical modification/crosslinking in medium of supercritical CO2 is proceeded in order to improve its hemostatic or anticoagulation function. Chemical modified collagen is prepared by the method of "extracting collagen after chemical modification". At higher temperature, collagen reacts with epoxy sulfonate, epoxy silicone, epoxy quaternary ammonium salt and heparin respectively. By such method make react temperature higher, react speed faster, and make more chemicals confirm the requests of chemical modification, solving the problem of collagen's low stability. Later, chemical modified collagen with water soluble, hydrophobic, antimicrobial properties, anticoagulation function is got by extracting collagen separately. Collagen is crosslinked with dialdehyde shell oligosaccharides, epoxy compound, carbodiimide, and genipin separately or with some of these chemicals all at once, in order to improve the physical and mechanical properties and structure stability of collagen. After crosslinking, small functional molecular substances such as RGD are used for blocking, making residual chemical reactive group with function, to improve the biocompatibility. After modification, to guarantee the biocompatibility of collagen, residual modifiers are removed by using supercritical CO2. The implementation of this project can overcome the defects of collagen, and enhance the function of collagen.

本课题针对胶原物理机械性能差、溶解性不佳、降解速度快、缺乏抗菌/抑菌功能等缺陷，为进一步提升止血或抗凝血功能，在超临界CO2介质中进行功能化化学修饰或交联。研究"先化学修饰后胶原提取"的方法制备化学修饰胶原，在较高温度下分别与环氧磺酸盐、环氧有机硅、环氧季铵盐、肝素等进行化学修饰，反应温度更高、速度更快，能够使更多的化学物质满足修饰的需要，克服了胶原溶液热稳定性低而导致的反应条件受限的问题。后期进行胶原提取，从而分别得到水溶性、疏水性、抗菌性、抗凝血功能化修饰胶原；分别或适当复合双醛壳寡糖、环氧化合物、碳化二亚胺、京尼平、交联与胶原交联，以提高胶原的物理机械性能和结构稳定性，交联后加入小分子功能物质（如RGD）封端，将残留化学活性基团功能化，提高生物相容性。在改性结束后，利用超临界CO2的萃取性能，除去残留改性剂，保证胶原改性后的生物相容性。通过本项目的实施，可以克服胶原的缺陷、增强胶原的

课题针对胶原物理机械性能差、溶解性不佳、降解速度快、缺乏抗菌/抑菌功能等缺陷，开展在超临界CO2介质中进行功能化化学修饰或交联的研究。（1）比较了在超临界CO2流体、丙酮、乙醇三种介质中，乙二醇缩水甘油醚（EGDE）交联脱细胞猪真皮基质（pADM）的性能，论证了功能化修饰和交联在超临界CO2流体中比普通溶剂中具有更高的反应效率，制备出的材料生物相容性优良。（2）研究了单环氧有机硅功能化修饰胶原，提高了胶原的疏水性能，指出了非交联条件下，可通过提高胶原疏水性能以改善其耐降解性；开展了环氧丙磺酸钠功能化修饰胶原的研究，改善了胶原的亲水性能，该结果对于胶原基敷料的“湿润愈合”具有参考意义。（3）采用优良的天然止血剂“三七素”、氧化壳聚糖、双醛羧甲基纤维素对胶原进行功能化修饰并揭示其分子作用机制，提高了胶原的凝血功能，对胶原更好应用作止血材料指明了方向。采用高碘酸钠将肝素钠氧化，然后交联胶原，氧化度低，抗凝血功能不明显。（4）研究了原花青素、功能性多糖衍生物“氧化海藻酸钠”、“氧化壳寡糖”交联胶原，胶原材料的耐降解能力明显提高，阐明了提高胶原稳定性的交联机制，揭示其功能化构效关系，为拓展胶原的生物交联剂开辟了道路。（5）通过先化学修饰后酶法提取获得了亲水性胶原，但反应较慢，提取率较低，不适于大规模提取。（6）采用神经传导物质“多巴胺”、氧化海藻酸钠、氧化石墨烯（GO）-碳化二亚胺盐酸盐功能化修饰胶原，研发出具有强烈黏合功能的胶原基水凝胶。（7）采用多次清洗、甘氨酸、赖氨酸和1640培养基对氧化多糖交联后的胶原进行后处理，论证了后处理方法对降低细胞毒性和提高生物相容性的有效性。通过本课题的研究，阐明了提高和赋予胶原功能性的途径和原理，开发出系列功能化胶原新方法，为进一步拓展胶原在生物材料方面广泛应用奠定了基础。