Chitosan nerve conduit filled with ZIF-8-functionalized guide microfibres enhances nerve regeneration and sensory function recovery in sciatic nerve defects

Nerve conduits have shown promise as alternatives to autologous nerves, but their repair effects need to be improved. The topographical guidance and functionalization of scaffolds are crucial in nerve repair. In this work, a chitosan-based nerve graft filled with guiding fibres modified by ZIF-8 nanoparticles (CS@ZIF-8) was fabricated for defective nerve repair. An in vitro study demonstrated that CS@ZIF-8 exhibited excellent cytocompatibility and could significantly promote Schwann cell proliferation. In vivo, nerve conduits filled with CS@ZIF-8 were observed to guide stronger axonal longitudinal elongation. Rats bridged with the conduit filled with CS@ZIF-8 showed significant morphological and functional improvements in terms of regenerated nerve density, the number of myelinated nerve fibres, the number of myelin layers, the thickness of myelin sheath, target muscle recovery and sensory function compared to those transplanted with the hollow conduit and the conduit filled with pure chitosan fibres. The repair effects achieved by using the conduit filled with CS@ZIF-8 were similar to those of autografts. Altogether, the data here show that nerve conduits filled with ZIF-8-loaded guide fibres provide a promising approach for repairing nerve defects.