Genipin-treated chitosan nanofibers as a novel scaffold for nerve guidance channel design

Schwann cell-seeded nerve guidance channels are designed to assist post-traumatic nerve regeneration in the PNS. Chitosan is a natural polymer well suited for tissue engineering as it is biocompatible, non-immunogenic, and biodegradable. Electrospun chitosan nanofibers utilized in nerve guidance channels have the capacity for guiding axonal growth within the channel lumen yet are limited in their capacity to maintain structural integrity within physiological environments. To address this, we attempted genipin crosslinking of chitosan nanofibers. Compared to neat chitosan nanofibers, genipin-treated nanofibers exhibited increased stiffness, resistance to swelling and lysozymal degradation. Furthermore, alignment and proliferation of purified Schwann cell cultures upon genipin-treated substratum was enhanced. When dorsal root ganglion explants were utilized as an in vitro model of peripheral nerve regeneration, emigrating neurons and Schwann cells assumed the uniaxial pattern of aligned electrospun chitosan nanofibers. Neurite growth along the nanofibers led, reaching a frontier more than twice that of the pursuant Schwann cells. Critically, neurite growth rate upon genipin-treated nanofibers demonstrated a 100% increase. Altogether, genipin treatment improves upon the physical and biological properties of chitosan nanofibers towards their utility in nerve guidance channel design.