Anisotropically Conductive Biodegradable Scaffold with Coaxially Aligned Carbon Nanotubes for Directional Regeneration of Peripheral Nerves

Abstract

Fascicular rearrangement of an injured peripheral nerve requires reconnection of nerve sprouts from anterior and Büngner bands from distal sides of the lesion, failing to which leads to inefficient regeneration of the injured nerve. However, existing neural scaffolds have limited neuroregeneration 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. The present study reports a biocompatible, multiwall carbon nanotube (MWCNT)-reinforced, anisotropically conductive, electrospun, aligned nanofibrous scaffold, ensuring maximal peripheral nerve regeneration. Electrospinning parameters were modulated to deposit random and parallel fibers in separate scaffolds for comparative analysis on the effect of fiber alignment on regeneration. Both types of scaffolds were reinforced with MWCNTs to impart electrical conductivity. Nonreinforced scaffolds were nonconductive. In this comparative study, MWCNT-reinforced, aligned scaffolds showed better tensile property with increased conductivity along the direction of alignment, thereby ensuring an escalated neural-regeneration rate. Collectively, in vitro studies established the scaffolds to be highly biocompatible, promoting cell 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. Rigorous revivification of the tissue was due to coordinated Wallerian degeneration and expedited guided axonal regeneration. 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 notes the efficacy of the coaxially aligned, MWCNT-reinforced neural scaffold, with a capability of establishing remarkable advancement in the field of peripheral neural regeneration.