Nerve conduits based on immobilization of nerve growth factor onto modified chitosan by using genipin as a crosslinking agent

• Published in: European journal of pharmaceutics and biopharmaceutics Vol. 79; no. 3; pp. 519 - 525
• Main Authors: Yang, Yumin, Zhao, Weijia, He, Jianghong, Zhao, Yahong, Ding, Fei, Gu, Xiaosong
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.2011; Elsevier
• Subjects: Animals; Animals, Newborn; Biocompatible Materials - chemistry; Biological and medical sciences; Cell Culture Techniques; Cell Proliferation - drug effects; Cell Survival - drug effects; Chitosan; Chitosan - chemistry; Controlled release; Cross-Linking Reagents - chemistry; General pharmacology; Genipin; Iridoids - chemistry; Medical sciences; Microscopy, Electron, Scanning; Nerve conduits; Nerve growth factor; Nerve Growth Factor - administration & dosage; Nerve Growth Factor - pharmacology; Nerve Regeneration - drug effects; Neurites - drug effects; PC12 Cells; Peripheral nerve regeneration; Peripheral Nerves - drug effects; Peripheral Nerves - ultrastructure; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Rats; Rats, Sprague-Dawley; Schwann Cells - drug effects; Schwann Cells - ultrastructure; Nerve growth factor; Chitosan; Peripheral nerve regeneration; Nerve conduits; Controlled release; Genipin; Pharmaceutical technology; Controlled release form; Control release polymer; Immobilization; Crosslinking; Regeneration; Chitosan derivatives; Dosage form; Oside polymer
• ISSN: 0939-6411; 1873-3441
• DOI: 10.1016/j.ejpb.2011.06.008

To fabricate chitosan (CS)-genipin (GP)-nerve growth factor (NGF) nerve conduits, genipin, a natural and low toxic agent, was used to immobilize NGF into a nerve conduit made up of modified CS. Immunocytochemistry confirmed that CS-GP-NGF nerve conduits kept the neural affinity of NGF, and the continuous release profile of NGF from CS-GP-NGF nerve conduits, within a 60-day time span, consisted of an initial burst that was controlled by concentration gradient-driven diffusion, followed by a zero-order release that was controlled by the degradation of CS. Incorporation of nerve growth factor (NGF) into a nerve conduit can improve peripheral nerve regeneration. Here, genipin, a natural and low toxic agent, was used to crosslink chitosan, a natural polysaccharide, and concurrently to immobilize NGF onto modified chitosan, followed by fabrication of chitosan (CS)–genipin (GP)–NGF nerve conduits. MTT test showed that the cell viability of Schwann cells cultured in the conduit extract was not significantly different from that in plain medium. The neurite outgrowth measurement and immunocytochemistry with anti-growth-associated protein-43 and anti-neurofilament indicated that NGF released from CS–GP–NGF nerve conduits retained the bioactivity of stimulating neuronal differentiation of PC12 cells. Fracture strength measurements and vitamin B12 release analysis confirmed that CS–GP–NGF nerve conduits possessed good mechanical properties and adequate permeability. We also investigated the in vitro release kinetics of NGF from CS–GP–NGF nerve conduits by ELISA. The continuous release profile of NGF, within a 60-day time span, consisted of an initial burst that was controlled by a concentration gradient-driven diffusion, followed by a zero-order release that was controlled by a degradation of chitosan matrix. Collectively, CS–GP–NGF nerve conduits had an integrated system for continuous release of NGF, thus holding promise for peripheral nerve repair applications.