功能化自组装多肽水凝胶修饰仿基底膜管结构神经移植物修复周围神经缺损

Tissue-engineered nerve is an effective way to repair peripheral nerve defects. It is a research hotspot how to construct the favorable microenvironment of tissue-engineered nerve. The extensive studies have demonstrated that the biomimetic structure,biomimetic composition and growth factors of tissue-engineered nerve are crucial factors which affect reconstructive outcomes of long segmental nerve defects by tissue-engineered nerve. This project is based on the extracellular matrix from cauda equine as main material (biomimetic composition ) to construct 3D bionic nerve scaffold with internal honeycomb conduit, highly aligned electrospinning in the conduit and favorable mechanical properties through the method of electrostatic spinning technology (aligned bionics of conduit wall fiber), aligned conduit mold and freeze-drying method (biomimetic structure of axial microtubules). Compared with the normal neural basement membrane structures, the 3D bionic nerve scaffold has a high degree of simulation in the composition and internal structure. KLT/RGI-based functionalized self-assembling peptides were developed by conjugating the bioactive motif from VEGF and BDNF onto the C-terminal of the peptide RADARADARADARADA (RADA16-I) to form a new RADA/KLT/RGI peptide. Our previous study showed KLT/RGI could significantly enhance endothelial cell angiogenesis and promote motor nerve functional recovery. In this project, we will explore the main mechanisms of the mimic neural basement membrane structures and RADA/KLT/RGI peptide in the nerve regeneration and microenvironment reconstruction. The 3D bionic nerve scaffold composited KLT/RGI-based functionalized self-assembling peptides will be used to repair long segmental peripheral nerve defects and evaluated its feasibility.

周围神经缺损是临床治疗难题。如何制备具有仿神经基底膜管结构的神经移植物，模拟神经再生微环境，让更多的再生神经纤维跨越缺损与靶器官形成精确对接，是该领域研究的热点。本项目在前期研究工作基础上，①以细胞外基质（成分仿生）为主要原料，采用静电纺丝技术（管壁纤维取向仿生）和取向管道模具、冷冻干燥方法（轴向微管样结构仿生）制备内部蜂窝状多孔道、孔道内部纺丝高取向排列、力学性能良好的3D仿基底膜管结构神经移植物；②在前期研究发现RADA16-I/KLT/RGI功能化自组装肽水凝胶促壳聚糖导管移植物内血管生成和促运动功能恢复的基础上，探讨KLT/RGI功能化自组装肽水凝胶对雪旺细胞增殖、迁移、分化机制及对神经元轴突再生影响；③建立功能化自组装肽水凝胶修饰仿基底膜管结构神经移植物修复周围神经大段缺损的新技术，为周围神经缺损修复提供新的治疗策略。

周围神经缺损修复是临床治疗中的难题，治疗的难点在于如何让更多的再生纤维跨越缺损，并与靶器官形成准确对接。如何利用微纳结构、生物信号等要素仿生重建神经再生微环境，对组织工程神经移植物修复长距离神经缺损具有重要意义。项目组紧紧围绕“重建神经再生微环境”这一科研主线，采用静电纺丝技术、功能化多肽水凝胶制备技术在周围神经损伤与修复领域开展了系列特色工作。我们取得了研究成果包括：1）将去细胞马尾神经与可降解几丁质导管复合构建新型细胞外基质源性神经移植物，体内研究结果表明该成分仿生和结构仿生神经移植物能更好地促进坐骨神经修复及靶器官功能恢复，相关研究发表在Advanced Healthcare Materials杂志；2）采用静电纺丝技术构建取向拓扑结构神经导管，将取向神经导管修复大鼠坐骨神经 15mm缺损，研究结果显示取向神经导管有利于再生轴突快速通过缺损区，相关研究成果发表在Neural Regeneration Research杂志；3）采用静电纺丝技术和取向管道模具、冷冻干燥方法制备内部蜂窝状多孔道、孔道内部纺丝高取向排列的3D仿生支架，核心技术已获得国家发明专利1项（ZL 201510639623.8）；4）采用静电纺丝技术制备出新型螺旋纹修饰的柔性神经导管，该螺旋纹神经导管具有抗扭结、术中缝合张力小、防止管壁塌陷及易于术后康复锻炼等特点。体内研究表明其在体内修复3个月后仍保持神经导管柔性，具有与传统神经导管相似的修复效果，相关研究结果发表在Biomaterials杂志；5）基于生物信号（NGF多肽、BDNF多肽等）构建功能化自组装多肽水凝胶体系，该功能化水凝胶具有与天然细胞外基质相似的微观结构及与神经组织相近的弹性模量，同时可为神经再生提供特定功能的微环境，相关研究结果发表在ACS Biomater. Sci. Eng.杂志。项目实施期间，项目组已在Biomaterials等国际杂志发表 SCI 论文8篇(标注基金号)，授权国家发明专利2项（ZL201510639623.8和ZL201811331708.X）；项目组基于微纳信号、生物信号等要素构建4种周围神经缺损修复策略；培养硕博士研究生4名，获评全军优秀博士学位论文1篇。