Viscoelastic and conductive nerve guidance conduits for peripheral nerve repair

Peripheral nerve injury is challenging to self-repair and often leads to severe functional impairment. Utilizing neural tissue engineering scaffolds to promote nerve regeneration presents a promising strategy. However, current nerve scaffolds generally lack the ability to accurately replicate the viscoelastic properties of native neural tissues. Here, aligned carbon nanotubes (ACNTs) were integrated onto the surface of gelatin methacryloyl (GelMA) with a 30% MA substitution degree (GelMA30), exhibiting viscoelastic properties closest to those of neural tissue, to fabricate GelMA30-ACNT (GM30-ACNT) scaffolds. Subsequently, an additional outer layer of GelMA with a 90% MA substitution degree (GelMA90) was applied to construct GelMA30/90-ACNT (GM30/90-ACNT) nerve guidance conduits (NGCs), aiming to enhance the mechanical properties of the NGCs. The scaffolds exhibit viscoelastic properties close to those of nerve tissues while retaining the topological guidance cues and excellent conductivity of ACNTs. The results demonstrated that the prepared GM30/90-ACNT substrates supported the growth and differentiation of pheochromocytoma (PC12) in vitro and significantly promoted the oriented extension of neurites. Additionally, the NGCs based on the GM30/90-ACNT scaffold significantly facilitated nerve regeneration and motor function recovery in a rat sciatic nerve injury model. These findings suggest that viscoelastic and conductive scaffolds represent a promising alternative for peripheral nerve injury repair.