A conducting neural interface of polyurethane/silk-functionalized multiwall carbon nanotubes with enhanced mechanical strength for neuroregeneration

A fibrous scaffold, fully assimilating polyurethane (PU) and silk fibroin associated with functionalized multi-walled carbon nanotubes (fMWCNTs) was developed by electrospinning technique. Herein, we engineered the PU/Silk fibroin-fMWCNTs-based biomaterial that shows great promise as electrospun scaffolds for neuronal growth and differentiation, because of its unique mechanical properties, hydrophilicity, and biodegradability, with outstanding biocompatibility in nerve tissue engineering. The morphology and structural properties of the scaffolds were studied using various techniques. In particular, the presence of fMWCNTs enhances the electrical conductivity and plausible absorption of sufficient extracellular matrix (ECM). The in vitro tests revealed that the aligned scaffolds (PU/Silk-fMWCNTs) significantly stimulated the growth and proliferation of Schwann cells (S42), together with the differentiation and spontaneous neurite outgrowth of rat pheochromocytoma (PC12) cells that were particularly guided along the axis of fiber alignment. The conductive PU/Silk-fMWCNTs scaffold significantly improves neural expression in vitro with successful axonal regrowth, which was confirmed by immunocytochemistry and qRT-PCR analysis. Inspired by the comprehensive experimental results, the fMWCNTs-based scaffold affords new insight into nerve-guided conduit design from both conductive and protein rich standpoints, and opens a new perspective on peripheral nerve restoration in preclinical applications.