利用丝素蛋白/石墨烯有序纳米纤维构建导电神经导管并缓释NGF和GDNF修复周围神经缺损的研究

The repair of peripheral nerves remains a major challenge in regenerative neurobiology. Regenerative guides possessing critical features such as cell adhesion, physical guiding and conducting electricity are needed. To generate such a conduit, silk-graphene aligned nanofibers are prepared using electrospinning in this project. Silk fibroin is selected due to its biocompatibility and its ability to be electrospun for the formation of aligned biofunctional nanofibers. Graphene is selected due to its excellent electrical properties. In addition, the silk-graphene electrospun nanofibers developed by coaxial electrospinning are able to provide sustained release of nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF) to enhance functions. Conductive properties, mechanical properties, permeability, degradation rate and neurotrophic factors release rate are used as the main indicators to determine the best ratio of silk fibroin to graphene and optimize the preparation conditions. Schwann cells and hippocampal neurons are cultured on the conductive nanofibers to investigate the cytocompatibility in vitro. Moreover, the silk-graphene conductive nerve conduit is used to regenerate rat sciatic nerve defects. Morphological, biochemical and electrophysiological methods are used to assess the regenerative effect. Therefore, the goal of this project is to synthesize a conductive nerve conduit with silk fibroin-graphene aligned nanofibers which can provide sustained release of NGF and GDNF, attempting to develop a promising nerve conduit for peripheral nerve regeneration in the clinic.

如何促进周围神经损伤的再生和功能重建一直以来都是国内外神经科学领域研究的难点和热点。本项目在申请人以往对丝素蛋白研究工作的基础上，拟将具有优异导电性能的石墨烯和具有良好生物相容性的丝素蛋白结合起来，采用静电纺丝同轴共纺技术制备能够同时缓释NGF和GDNF两种神经营养因子的、有序排列的丝素蛋白/石墨烯导电纳米纤维，并利用丝素蛋白/石墨烯导电纳米纤维构建神经导管。以导电性能、力学性能、渗透性能、降解速度和神经营养因子的释放速度为主要指标，确定丝素蛋白和石墨烯之间的最佳比例并优化制备条件。利用施旺细胞和海马神经元体外考察导电纳米纤维的细胞相容性，并进一步应用导电纳米纤维神经导管修复大鼠坐骨神经缺损，采用形态学、生物化学和电生理学等方法评估修复效果。以寻求更适合临床应用的神经修复导管，为神经修复支架材料的开发提供新思路，在周围神经损伤的修复方面进行一些有益的尝试。

如何促进周围神经损伤的再生和功能重建一直以来都是国内外神经科学领域研究的难点和热点。本项目在负责人以往对丝素蛋白研究工作的基础上，将具有优异导电性能的石墨烯和具有良好生物相容性的丝素蛋白结合起来，采用静电纺丝技术制备有序排列的丝素蛋白/石墨烯导电纳米纤维，并利用丝素蛋白/石墨烯导电纳米纤维构建神经导管。确定丝素蛋白和石墨烯之间的最佳比例并优化制备条件，利用神经细胞体外考察导电纳米纤维的细胞相容性。同时，在丝素蛋白多孔支架上成功制备了聚吡咯-氧化石墨烯二元涂层，使其表现出优异的电化学性能和力学性能，并进一步将iPSCs接种在丝素蛋白-石墨烯复合薄膜材料表面诱导其向神经细胞方向分化，为神经修复支架材料的开发提供了新思路。本项目共发表高水平SCI论文7篇；培养博士研究生4人，硕士研究生6名；参加了第四届新型高分子材料与控制释放国际会议、2017全国生物材料大会以及2018全国再生医学材料大会。