用于修复受损神经网络的短肽金属水凝胶的设计及自组装机理探索

The main mission of this project is to construct a series of self-developed metallogel systems as in vitro templates to prove our original proposes for building up a new protocol to re-establish and repair the blocked cross-link among neuron cells with Vitamin B12 liked metallogels. Some recent reports indicated that the memory lapse and cognitive disorder caused by neurodegenerative diseases and craniocerebral injuries can be improved or repaired through repairing and reconstruction of the connection among nerve cells. The principle is similar to the rebuilding of the partition pointer to find the loss data on the hard disk. Inspired by the hand book of “Brain Research through Advancing Innovative Neurotechnologies, BRAIN” from the United States and the extremely useful technique "CLARITY " for studying the nervous system of cerebrum, we here promote a protocol to construct a series of Vitamin B12 liked metallogels to re-establish and repair the impaired neural network. Our experimental results convinced that introducing the core structure of Vitamin 12 in to certain peptides resulted in a Co(II)-selective and chirality-sensitive supramolecular metallohydrogel with a nanofiber network skeleton. Our results were in good agreement with the cell viability tests. This interesting metallohydrogel shows potential for developing new soft materials to construct three dimensional (3D) interactions among 3D neuron cells which cultured in the metallohydrogel system. By combining two well-established techniques: atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM), we are able to monitor the self-assembly mechanism of this kind of metallohydrogel. To identify the noncovalent interactions among the monomers and other aggregates is of great important to obtain the insights into the gelation process of this kind of metallohydrogelators. .The second mission of this project is to use the protocol we established to apply quick and High-throughput drug screening for the "memory lost" caused by Alzheimer Disease and brain injury and so on.

国内外最新研究结果显示，人类大脑中存在极少量的原生干细胞，在未知条件激发时可能随机修复并重构受损神经细胞之间的联系。 该发现为人工修复和改善疾病及颅脑伤引起的神经网络受损提供了客观依据。受研究大脑神经体系利器 “透明大脑技术”启发，本课题首次提出使用与维生素B12核心片段具有类似结构的短肽金属凝胶来激发、诱导大脑原生干细胞的定向生长，进而对局部受损的神经网络进行靶向性修复的一种方案。 设计、筛选各种新型水凝胶， 总结其在体外环境下激活原生干细胞的定向生长行为与本身结构的规律性联系，是现阶段本研究的核心目标。拟构筑一个和人体大脑环境近似的体外体系，利用改进的表界面化学的分析测试手段，原位观测不同结构单元的短肽金属凝胶因子的自组装-解组装的形貌学及动力学行为，归纳总结各类短肽金属凝胶对原生干细胞分化、生长及转化过程中的规律。 课题的实时能够为研究复杂生物体系提供一种实时、微观的原位观测方法。

在本项目基金的资助下，工作按计划进行，取得了一系列的进展，研究成果主要包括以下几个内容：1. 验证了包括短肽金属凝胶在内的多种天然小分子金属凝胶对神经细胞突触生成的正面作用。证实了一些金属短肽凝胶可以促进神经细胞的突触生长，分化，交联。这一突破性的发现，为研究部分恢复神经退行性疾病患者记忆的研究提供了体外实验证据。2.改进了利用天然小分子凝胶培养神经干细胞的实验方案，实现了神经干细胞的无血清培育。探索并证实了利用小分子凝胶在4摄氏度保存神经干细胞外泌体及RNA适配体的可行性。3. 建立了使用小分子凝胶作为药物递送平台及药物直接递送系统，通过鼻粘膜给药实现了对帕金森小鼠的治疗的方案。4. 建立了一种能够有效筛选对由于神经退行性疾病引起的记忆缺失的天然小分子凝胶的策略，从中筛选了以大黄酸单体，大黄酸及大黄酸锌、钴水凝胶对脑损伤引起的脑水肿及脑部神经炎症的治疗作用。这部分工作，为中药单体分子的直接给药，特别是注射型给药提供了一个示范性模板，为促进中药产品的规范化、定量化应用提供了一个有意义的研究方向。例如，课题组也尝试将七叶皂苷凝胶用于眼底视神经网络修复，双醋瑞英凝胶用于骨关节炎治疗，均取得了较好的效果。.此外，在新冠疫情期间，开发了一系列潜在新冠治疗小分子药物凝胶剂疫苗载体凝胶，成功制备了瑞德西韦，地塞米松（纯）小分子凝胶，验证了含有西韦类基团的小分子的成胶性能，验证了鼻粘膜给药及气溶胶雾化直接肺部给药的可行性。