Electrodeless coating polypyrrole on chitosan grafted polyurethane with functionalized multiwall carbon nanotubes electrospun scaffold for nerve tissue engineering

Herein, we engineered a self-electrical stimulated double-layered nerve guidance conduit (NGC) assembled from electrospun mats with an aligned oriented inward layer covered with a random oriented outer layer. The biomimetic NGC can be achieved from chitosan grafted polyurethane with well-dispersed functionalized multiwall carbon nanotubes (fMWCNTs) nanofibrous mats after a uniform coating of polypyrrole (PPy). The structural framework of interconnected NGC exhibited cellular biomaterial interface and improved the physicochemical properties, including electrical conductivity, mechanical strength, and cytocompatibility, serving as natural hosting substrate to natural extracellular matrices (ECM) for vital roles in nerve tissue engineering. The regrowth, proliferation, and migration, of Schwann cells (S42) and the differentiation of rat pheochromocytoma cells (PC12) were greatly accelerated on the aligned oriented mats as compared to the randomly oriented mats during in vitro cell cultures. The morphology of the spontaneous outgrowth and phenotype of neurite bundles were preferentially guided along the axis of the aligned oriented nanofibers, which maintains a strong adaptability in axonal regeneration. In addition, the differentiation of PC12 cells cultured on as-fabricated NGCs were evaluated from cDNA gene expression. It is hoped that the results will contribute to the efficient application of designed NGCs and can be used in therapeutic strategies for treating injured sites and stimulate recovery from substantial damage to nerve cells.