3D打印高强度物理水凝胶及其在可控变形、细胞支架中的应用研究

The developments of various tough hydrogels have greatly broadened the applications of gel materials in different fields. In practical applications, precise control of gel's shape and structure is really required. However, in the preparation of most tough hydrogels, polymerization and gelation are completed in one single step; therefore, the shape of resulting hydrogels depends on the reaction mold. How to process tough hydrogels in a facile yet effective approach has become a fundamental issue to be solved. In this project, we propose to develop processable tough physical hydrogels by separating the toughening process from the polymerization and preparing the gels via spin-coating and gelation of a polymer solution. The structure-property relationship of the resultant tough gels will be investigated. On this basis, extrusion-based printing will be applied to fabricate tough hydrogels with programmed structures, in which polymer solution will be used as the printing material and an adjustable printing stage will be simultaneously moved to temporally control the sinking of printed material and the gelation time. The printing process and parameters will be optimized toward high printing resolution, shape fidelity, binding strength between gel fibers at different layers, and mechanical performances of printed structure. Composite printed structures will be obtained by multi-nozzle printing of different materials or filling another gel in the printed gel structure, and their potentials will be demonstrated as controllable deformations and cell culture scaffolds. This project will provide a novel avenue for processing tough hydrogels and promote the applications of hydrogels in different areas such as flexible devices.

高强度水凝胶的开发大幅拓展了凝胶材料的应用领域；在实际应用中，材料外部形状与内部结构的精确控制至关重要。但是，高强度水凝胶制备时，聚合与凝胶化往往同步完成，导致其形状依赖于反应模具。如何通过简单有效的方法实现高强度水凝胶的成型加工，成为亟需解决的重要基础问题。本项目拟通过聚合物溶液旋涂、凝固浴中凝胶化的步骤，使成型与强韧化过程分开，制备不同类型的高强度物理水凝胶薄膜，揭示其结构-性能关系；在此基础上，以聚合物溶液为打印材料，在挤出过程中同步移动打印平台，控制打印结构进入凝固浴中凝胶化的时间点，实现高强度水凝胶的挤出打印与成型加工；通过打印工艺的设计与优化，调控打印精度、结构保真度、层间粘结强度以及整体力学性能；通过多喷头打印或者先打印后填充的方法制备多组分复合凝胶，探索其在可控变形、细胞培养支架中的应用。该研究将为高强度水凝胶的成型加工提供新的思路和方法，拓宽水凝胶在柔性器件等领域的应用。

高强度水凝胶的开发大幅拓展了凝胶材料的应用领域，柔性器件、软驱动器等实际应用需要对凝胶材料外部形状与内部结构进行精确控制。通过简单有效的方法实现高强度水凝胶的成型加工，成为亟需解决的重要基础问题。本项目通过将聚合与凝胶化过程分离，在特定条件下实现凝胶化、强韧化，从而实现了高强度水凝胶的成型加工与结构控制。采用聚合物溶液旋涂、凝固浴中凝胶化步骤，制备了高强度物理水凝胶薄膜，揭示了其结构-性能关系、力学破坏过程及增强机制。在此基础上，以高粘聚合物水溶液为打印材料，打印后通过形成离子键、配位键完成结构固定，获得了具有可控三维结构的高强度水凝胶；研究了聚合物浓度、凝胶化条件、打印工艺对打印精度、粘结强度以及整体力学性能的影响。通过多喷头打印不同响应性水凝胶，或者先打印高强度凝胶后填充含有细胞的弱凝胶，制备多组分复合水凝胶，研究了其在可控变形、细胞培养支架中的应用。该研究为高强度水凝胶的成型加工提供新的思路和方法，有利于拓宽水凝胶在柔性器件、组织工程等领域的应用。通过该项目的开展培养了本科生5名，硕士研究生1名，博士研究生3名，博士后1名；以通讯作者在Adv. Mater. (5篇)、Nat. Commun.、Adv. Funct. Mater. (3篇)、Macromolecules (5篇) 等高水平期刊上发表论文42 篇，获得授权发明专利4项，提交了国内外学术会议论文16篇，完成了各项预定目标。