Fabrication of Anatomically\nEquivalent Pectin-Based\nMultifilament Nerve Conduits

Reuniting\ndenuded nerve ends after a long segmental peripheral\nnerve defect is challenging due to delayed axonal regeneration and\nincomplete, nonspecific reinnervation, as conventional hollow nerve\nguides fail to ensure proper fascicular complementation and obstruct\naxonal guidance across the defects. This study focuses on fabricating\nmultifilament conduits using a plant-derived anionic polysaccharide,\npectin, where the abundant availability of carboxylate (COO−)\nfunctional groups in pectin facilitates instantaneous sol–gel\ntransition upon interaction with divalent cations. Despite their advantages,\npectin hydrogels encounter structural instability under physiological\nconditions. Hence, pectin is conjugated with light-sensitive methacrylate\nresidues (49.8% methacrylation) to overcome these issues, enabling\nthe fabrication of dual cross-linked multifilament nerve conduits\nthrough an ionic interaction-driven, template-free 3D wet writing\nprocess, followed by photo-cross-linking at 525 nm. The anatomical\nequivalence including peri-, epi-, and endoneurium structures of the\ncustomized multifilament conduits was confirmed through scanning electron\nmicrographs and micro-CT analysis of rat and goat sciatic nerve tissues.\nFurthermore, the fabricated multifilament nerve conduits demonstrated\ncytocompatibility and promoted the expression of neuron-specific intermediate\nfilament protein (NF-200) in PC12 cells and neurite outgrowth of 16.90\n± 1.82 μm on day 14. Micro-CT imaging of an anastomosed\nnative goat sciatic nerve with an 8-filament conduit demonstrated\nprecise fascicular complementation in an ex vivo interpositional goat\nmodel. This approach not only eliminates the need for a suture-intensive\nligation process but also highlights the customizability of multifilament\nconduits to meet patient- and injury-specific needs.