Novel flexible nerve conduits made of water‐based biodegradable polyurethane for peripheral nerve regeneration

Peripheral nerve conduits were fabricated from biodegradable polyurethane (PU) which was synthesized by a waterborne process. The biodegradable PU was based on poly(ε‐caprolactone) diol and polyethylene butylene adipate diol (2:3 molar ratio) as the soft segment. Conduits formed by the freeze‐drying process had asymmetric microporous structure. The PU nerve conduits were used to bridge a 10‐mm gap in rat sciatic nerve. Nerve regeneration was evaluated by walking track analysis, magnetic resonance imaging (MRI), electrophysiological, and histological analyses. Results demonstrated that after 6 weeks, walking function was recovered by 40%. MR images showed that the transected nerve was reconnected after 3 weeks and the diameter of the regenerated nerve increased from 3 to 6 weeks. The nerve conduction velocity of the regenerated nerve reached 50% of the normal value after 6 weeks. Histological examination revealed that the cross‐sectional area of the regenerated nerve at the midconduit was 0.24 mm2 after 6 weeks. The efficacy of PU nerve conduits based on functional recovery and histology was superior to that of commercial conduits (Neurotube). The PU nerve conduit developed in this study may be a potential candidate for clinical peripheral nerve tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1383–1392, 2017.