Title: Anisotropically electro-conductive biodegradable scaffold with coaxially aligned carbon nanotubes for directional regeneration of peripheral nerves
In an injured peripheral nerve fascicular rearrangement needs reconnection of nerve sprouts from anterior and Büngner bands from distal sides of the injury. Failing to that results in inefficient structural and functional regeneration of the injured nerve. However, existing neural scaffolds have limited neuro-regeneration efficiency because of either the lack of alignment of fibers and a conductive second phase leading to compromised electrical conductivity, or the lack of extracellular matrix components and in vivo validation. In the present study, the synthesis of a biocompatible, multiwalled carbon nanotube (MWCNT)- reinforced, anisotropically conductive, electrospun, aligned nanofibrous scaffold has been reported ensuring maximal peripheral nerve regeneration. This study mainly focused on the synthesis of two different types of scaffolds based on the fiber orientation and comparative analysis of the effect of fiber orientaion on peripheral nerve regeneration. Both types of scaffolds were reinforced with MWCNTs to impart electrical conductivity. This study showed, MWCNT-reinforced, aligned scaffolds have better tensile property with increased conductivity along the direction of alignment, thereby ensuring an escalated neural-regeneration rate. Overall, in vitro cell culture studies with IMR-32 cells indicated the scaffolds to be highly biocompatible and promoted cellular growth and proliferation. With 85% more anisotropic conductivity in the direction of the alignment and the degradation kinetics tuned to the regeneration regime, the MWCNT-reinforced, aligned scaffold efficiently healed injured sciatic nerves in rats within 30 days. Structural and functional analysis of nerves in vivo showed the aligned, MWCNT-reinforced scaffold to be very efficient in peripheral sciatic nerve regeneration. This study documented the efficacy of the coaxially aligned, MWCNT reinforced neural scaffold, with a capability of establishing remarkable advancement in the field of peripheral neural regeneration.