2. 丝素-P（LLA-CL）静电纺纳米纤维神经导管的制备用于周围神经的再生

2. 丝素-P（LLA-CL）静电纺纳米纤维神经导管的制备用于周围神经的再生

      周围神经损伤是临床常见疾患，其愈后差，致残率高，给病人、家庭和社会带来巨大的经济损失和精神负担。因此，如何促进神经的再生、恢复靶器官的功能一直是全社会关注的热点。对于周围神经缺损，自体神经移植仍是目前修复的“金标准”。其主要缺点是：自体神经取材来源有限，供体与受体神经直径不匹配，同时切取自体神经时也将造成供区的损伤及一定的功能障碍。因此寻找自体神经的替代物以及促进神经再生成为研究的热点。利用生物材料构建的神经再生导管，不仅可以为神经细胞获取营养、生长和代谢提供了一个有利的空间，还具有减轻缝合口的张力，引导神经纤维的生长，提高神经束对合的精确度，防止瘢痕组织侵入再生的神经纤维等优点。美国已有PGA导管商业化生产（Neurotube, Neroregen L.L.C. USA）,但此产品所用材料降解速度太快，不能用于长距离神经的修复。我国还没有神经导管产品。因此开发神经导管的研究，特别是修复长距离神经缺损具有重要的医学应用价值和社会效益。本实验室制备各种神经导管用于神经再生，所用原料是丝素蛋白和乳酸己内酯共聚物（P(LLA-CL)）。分别制备出了P(LLA-CL)纳米纤维神经导管和丝素-P(LLA-CL)复合纳米纤维神经导管，动物实验结果表明丝素-P(LLA-CL)复合纳米纤维神经导管与未加丝素的纯P(LLA-CL)神经导管相比更有利于神经组织的再生和神经功能的恢复。为了能修复长距离神经缺损我们又对神经导管进行了更进一步的优化设计，一是设计制备出轴向取向神经导管制备装置，可以使静电纺纳米纤维轴向取向，得到轴向取向纳米纤维神经导管促进神经再生；二是利用同轴共纺技术将神经生长因子和神经节苷脂纺在纳米纤维中，得到含生长因子的轴向取向丝素-P(LLA-CL)复合纳米纤维神经导管，此导管已经用于1.5cm距离大鼠坐骨神经缺损的修复；三是在神经导管中填充多孔纳米纤维海绵，让神经细胞附着在多孔纳米纤维海绵上生长，在用于大鼠坐骨神经缺损的修复上表现出促进神经快速完美修复的作用。

2. Silk fibroin-P (LLA-CL) electrospun nanofiber nerve conduit preparation for peripheral nerve regeneration

Peripheral nerve injury is a common clinical disease, which has a high disability rate, brings huge economic losses and mental burden to patients, families and society. Therefore, how to promote the regeneration of nerves and restore the function of target organs has always been a hot spot of concern for the whole society. For peripheral nerve defects, autologous nerve transplantation is still the "gold standard" for current repair. The main disadvantages are: the source of autologous nerves is limited, the donor and recipient nerve diameters do not match, and the autologous nerves will also cause damage to the donor site and certain dysfunction. Therefore, the search for alternatives to autologous nerves and the promotion of nerve regeneration have become the focus of research. The nerve regeneration conduit constructed by biomaterials not only provides a favorable space for the nerve cells to obtain nutrition, growth and metabolism, but also reduces the tension of the suture, guides the growth of the nerve fibers, and improves the precision of the nerve bundles.  It prevents the scar tissue from invading the regenerated nerve fibers. The United States has commercialized the production of PGA conduit (Neurotube, Neroregen L.L.C. USA), but the materials used in this product degrade too fast and cannot be used for the repair of long-distance nerves. There are no nerve conduit products in China. Therefore, the development of nerve conduit research, especially the repair of long-distance nerve defects has important medical application value and social benefits. Our laboratory prepares various nerve conduits for nerve regeneration using the silk fibroin and caprolactone copolymer (P(LLA-CL)). P(LLA-CL) nanofiber nerve conduit and silk fibroin-P(LLA-CL) composite nanofiber nerve conduit were prepared respectively. The results of animal experiments showed that silk fibroin-P(LLA-CL) composite nanofiber nerve conduit more beneficial to the regeneration of nerve tissue and the recovery of nerve function compared with the pure P (LLA-CL) nerve conduit. In order to repair long-distance nerve defects, we have further optimized the nerve conduit. First, we designed and prepared an axially oriented nerve conduit with electrospun nanofibers axially oriented, which promoted the nerve regeneration; secondly, nerve growth factor and ganglioside are spun in nanofibers by coaxial spinning technique to give nerve conduit, which has been used for the repair of rat sciatic nerve defects at a distance of 1.5 cm. The third is to fill the nerve tube with a porous nanofiber sponge, allowing nerve cells to attach to the porous nanofiber sponge for growth, and to be used for the repair of rat sciatic nerve defects.  It shows the role of promoting rapid and perfect repair of nerves.