Conducting Biomaterials for Nerve Regeneration

描述(申请人提供)：在美国，每年有100多万人遭受严重的周围神经损伤，每年需要进行2万例手术来修复切断的周围神经。神经引导通道(NGCs)是一种中空管道，用来桥接切断的周围神经的大间隙。目前的NGC材料有许多缺点，这些缺点经常妨碍它们的使用或导致该过程的失败。因此，需要积极促进神经再生的新型生物材料来构建改良型NGCs。 导电生物材料之所以引起人们的兴趣，是因为它们可以用来向成骨细胞、内皮细胞和神经元等响应性细胞传递电刺激。聚吡咯(PPy)是一种无细胞毒性的导电聚合物，已被证明有利于大鼠受损周围神经的再生。由于PPy是一种半导体，它可以用来向培养的细胞传递电刺激，加速它们的生长、迁移和增殖。不幸的是，PPy不是可生物降解的，由PPy制成的NGCs在愈合后必须从体内移除，需要二次手术，并导致额外的部位发病率。此外，PPy像大多数导电聚合物一样，不溶不熔，机械性能较差。因此，将其加工成必要的形式是非常困难的。这些特性限制了聚吡咯在组织工程中的实际应用。 本项目的目标是制造一种可以从溶液中加工的可生物降解的PPy形式，并测试其作为切断的神经再生的载体的性能。在一期工程中，TDA成功地制备了一种PPy基生物材料，这种材料具有导电性，可以从溶液中加工，并能很好地支持神经元的体外生长。

DESCRIPTION (provided by applicant): In the U.S. more than one million people suffer serious peripheral nerve injuries every year and 20,000 procedures are carried out annually to repair severed peripherals nerves. Nerve guidance channels (NGCs) are hollow conduits used to bridge large gaps of severed peripheral nerves. Current NGC's materials have many drawbacks that often preclude their use or cause failure of the procedure. Therefore, new biomaterials that actively promote nerve regeneration are needed for the fabrication of improved NGCs. Electrically conducting biomaterials are of interest because they can be used to deliver electrical stimulation to responsive cells like osteoblasts, endothelial cells, and neurons. Polypyrrole (PPy) is an electrically conducting polymer that is not cytotoxic and has been demonstrated to favor the regeneration of damaged peripheral nerves in rats. Because PPy is a semiconductor, it can be used to deliver electric stimuli to cultured cells, accelerating their growth, migration and proliferation. Unfortunately PPy is not biodegradable, and NGCs made of PPy must be removed from the body upon healing, requiring a second surgery and causing additional site morbidity. Moreover, PPy, like most conducting polymers, is insoluble and infusible, and has poor mechanical properties. Therefore, it is very difficult to process it into the necessary form. Together, these properties limit the practical applications of PPy in tissue engineering. The objective of this project is to make a biodegradable form of PPy that can be processed from solution, and to test its properties as a support for the regeneration of severed nerves. During the Phase I project TDA successfully prepared a PPy-based biomaterials that are electrically conducting, can be processed from solution and support well neuron growth in vitro.