纳米银－胶原蛋白组织工程周围神经支架的构建及其理化性能的检测

Construction of tissue-engineered scaffold for peripheral nerve regeneration with nano-sliver and col- lagen and their physical and chemical examinations

目的探讨纳米银－胶原蛋白组织工程周围神经支架的构建及其理化性能和生物相容性。方法采用不同浓度纳米银溶液构建含不同浓度纳米银（1、2、3、4、5、6mg／L）的胶原蛋白组织工程支架，对照组仅加入为含纳水银的等量纯水。分别以扫描电镜观察其横截面和纵截面孔径结构，测定微拉但强度。采用5只SD仔鼠进行纳米银-胶原蛋白支架细胞毒性实验，8只雄性成年SD大鼠进行支架体内降解实验，12只雄性成年SD大鼠行纳米银体内蓄积毒性测试。逐步按照空间结构以及化模拟体内环境下的多种理化特性筛选最佳纳米银含量的纳米银-胶原蛋白材料，构建周围神经支架。结果纳米银含量为1、2mg／L的纳米银-胶原蛋白支架内部孔径结构高度仿生，其中2mg／L纳米银含量组的支架抗拉伸强度达到0.22MPa，优于其他测试组、采用含2mg／L纳米银支架材料制作薄膜行雪旺细胞培养证实该支架材料无神经细胞毒性。体内降解实验显示该组织工程支架从植入体内外始缓慢发生降解，4个月后可以完全降解。纳水银体内蓄积毒性测试显示在支架植入体内直至完全降解过程中，脑、脊髓、肝和肾脏银元素含最均低于1ng／mL，不存在蓄积毒性。结论使用含2mg／L纳米银的胶原蛋白周围神经组织工程支架不仅在内部空间结构上可高度仿生周围神经，且具有较好的抗拉伸强度、在体内可完全降解、无细胞毒性和银蓄积毒性等优点。

Objective To construct a kind of nanosilver-embedded collagen seaffold for peripheral nerve regeneration and to investigate its physical and chemical characters anti bioeompatibility. Methods The nanosilver particles at different concentrations of 1. 2. 3, 4, 5 and 6 mg/L were added into collagen respectively while pure water of the same amount was added in the control groups. Improved eryodesiecation was used to construct the nanosilver-embedded collagen seaffoht with micro-channels. The uanosilver-eud）edded collagen scaffold suitable for the peripheral nerve was selected according to the diameters of micro-channels upon scanning electron microscopy and the lensile strength at the axial direction of the scaffohl. The in lifo eyloloxicity of the selected scaffohl was tested in 5 SD newborn rats, the in vivo degradation rate of tile selected seaffohl in 8 aduh male SD rats and the in rivo cumulative toxicity of the nanosilver in 12 aduh male SD rats. The best nanosilver-embedded collagen scaffold for peripheral nerve regeneralion after injury was determined according to the comprehensive properties examined. Results The micro-channels of the nanosilver-embedded collagen scaffold were the most suitable fi）r the peripheral nerve when the concentrations of nanosilver in the collagen were I or 2 mg/L. Tensile strength at the axial direction of the collagen scaffold embedded with 2 mg/L nanosilver was 0.22 MPa, better Ihan the other groups. The collagen seaffohl embedded with 2 rag/I, nanosilver degraded in vivo gradually anti completely after 4 months with no eytotoxieity or storage fo toxieity. The contents of silver in the brain, spinal cord, liver and kidney were all lower than 1 ng/mL. Conclusion The collagen seaffoht embedded with 2 mg/l, nanosilver best suits the peripheral nerve regeneration after injury, because it has good tensile strength, can be fully degraded in vivo, and is free from cytotoxicyty storage of toxicity.