Aligned graphene/silk fibroin conductive fibrous scaffolds for guiding neurite outgrowth in rat spinal cord neurons.

Graphene, as a highly conducting material, incorporated into silk fibroin (SF) substrates is promising to fabricate an electroactive flexible scaffolds toward neural tissue engineering. It is well known that aligned morphology could promote cell adhesion and directional growth. The purpose of this study was to develop aligned conductive scaffolds made of graphene and SF (G/SF) by electrospinning technique for neural tissue engineering applications. The physicochemical characterization of scaffolds revealed that the mechanical and electrochemical property of aligned G/SF scaffolds continually raised with the increasing contents of graphene (A0% G/SF, A1% G/SF, A2% G/SF, A3% G/SF), but the mechanical property descended when the graphene concentration reached to 4% (the A4% G/SF group). The results of cell experiment in vitro indicated that all the aligned G/SF scaffolds were no neurotoxic to primary cultured spinal cord neurons. In addition, the neurite elongation in all aligned groups was significantly enhanced by the up-regulation of Netrin-1 expression compared to them in the control group. Thus, A3% G/SF scaffolds not only possessed the optimal property based on the mechanical and electrochemical performances, but also displayed beneficial capability to neurite outgrowth, which might perform a suitable candidate to successfully scaffold electrically active tissues during neural regeneration or engineering.