微相分离超分子水凝胶的构建及其在组织工程中的应用

Hydrogels represent a group of materials with good biocompatibility, predictable degradation rates, holding large amounts of water, tuneable mechanical properties and good elasticity make them excellent materials for tissue scaffold applications. However, it is important and difficult to develop hydrogels with both high self-healing and mechanical strength. Up to now, there are mainly nanocomposite or double-network supramolecular hydrogels. While the macro phase separation was caused for the compatibility between the components is not good enough. The macro phase separation will affect the mechanical properties. Therefore, in this project, starting from the design of the polymer chains, supramolecular hydrogels was got based on the host-gust interaction; and microphase separation structure was obtained with the help of the thermodynamic incompatibility between the soft segment and hard segment; then microphase separation supramolecular hydrogels was prepared, and the aim of this project is to explore relationship between chain structure and material properties. Some useful rules will be summarized and explained based on rheological analysis, DMA, DSC, GPC, NMR, FT-IR, SEM, AFM etc. The influence such as structure and data of microphase separation on self-healing and mechanical strength performance will be systematically studied. The research will promote the development of the polymers with both high self-healing and mechanical strength and will provide a lot of important information on synthesis and safe application of hydrogels.

水凝胶具有良好的生物相容性、高可塑性、高含水量等特性，是一种理想的支架材料。发展兼具高自修复性和强力学性能的水凝胶支架材料，一直是研究水凝胶的重点与难点。目前，主要是采用纳米或双网络等结构，这些结构存在各组分之间相容性不够好，造成宏观上的相分离的问题，从而影响了其性能。因此本项目从高分子链的结构设计出发，以基于葫芦脲的主客体作用为驱动力制备超分子水凝胶；利用高分子链中的软段、硬段的热力学不相容，设计出微相分离结构；提出构建微相分离超分子水凝胶的研究课题，旨在探索此类高分子材料的结构与性能关系。通过结合流变分析、DMA、DSC、GPC、NMR、FT-IR、SEM、AFM等技术和手段，探讨水凝胶的组成、微相分离参数等对其自修复和力学性能的影响及其规律，从微观结构诠释所得构效关系。该研究工作将推进兼具自修复性和力学性能的高分子材料的发展，为水凝胶在生物医学中高效、安全应用，提供科学依据。

发展兼具高自修复性和强力学性能的水凝胶支架材料，一直是研究水凝胶的重点与难点。本工作基于超分子的主客体作用构建了具有自修复性能的超分子水凝胶，通过原位引入微米球以提升交联作用，构建了强力学性能的超分子水凝胶。发展多功能的超分子水凝胶，扩展其应用领域具有重要应用价值，本工作还分别将荧光分子、纳米材料及功能性的客体分子引入水凝胶体系中，并分别研究了其在水相光捕获、纳米催化的应用。研究主要分为以下四部分：.(1)通过葫芦[8]脲和客体分子的主客体作用作为交联驱动力构筑超分子水凝胶的网络。壳聚糖微球的引入使得拉伸强度和压缩强度提升了5倍，室温下24 h的自修复效率为88%。表明壳聚糖微球可作为多功能的引发和交联中心，主客体的动态作用提供了自修复性能。.(2)以超分子水凝胶为载体和反应器，制备出纳米金或纳米钯，将其应用于对硝基苯酚(4-Ap)的催化还原中，纳米金的反应的活化能为65.83 kJ mol−1，纳米钯的为39.99 kJ mol−1。复合催化剂具有良好的自修复和催化性能。.(3)通过主客体交联作用和四苯乙烯的的聚集诱导发光效应，制备出超分子荧光水凝胶，再吸收EY的水溶液，通过紫外可见吸收光谱，以及荧光发射光谱确认系统中发生了能量转移，成功构筑光捕获系统。.(4)基于二茂铁客体分子与主体分子葫芦[10]脲之间的动态主-客体作用为交联点的驱动力制备了超分子水凝胶。二茂铁的固有催化活性得以保留，对H2O2的检测限为2.5 × 10−4 mol/L。该研究为水凝胶功能化提供了新的方法，在生物和环境化学等领域具有潜在应用。