100 Section - 4D-Printed Regenerated Bacterial Cellulose Biomimetic Nerve Conduit Repairs Peripheral Nerve Defects via Non-Invasive Electromagnetic Induction

Peripheral nerve injury (PNI) disrupts motor, sensory, and autonomic functions. Autologous grafts are limited by donor scarcity, prompting nerve guide conduits (NGCs) to bridge defects. Current NGCs are restricted to < 30 mm gaps, with 10-26% failure rates. Conductive biomaterials in bioelectronics support cell growth and functional recovery. Magnetic stimulation (MS) non-invasively induces electromotive force via Faraday’s law. This study aims to integrate MS with conductive NGCs for novel PNI therapy.

Design:

This study utilized regenerated bacterial cellulose (RBC), carbon nanotubes (CNTs), and shape memory polymer (SMP) to fabricate a highly biocompatible "sandwich" structured RBC-CNT-SMP nerve conduit with excellent stiffness, elasticity, and adjustable dimensions via 4D printing technology. The conduit's microstructure and elemental distribution were characterized using electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and ion thinning. Hydrophilicity/hydrophobicity was assessed via contact angle and surface energy measurements. Finite element analysis evaluated changes in induced electromotive force under pulsed magnetic fields (MF). Therapeutic efficacy of RBC-CNT-SMP combined with MF was validated in a rat model of long-distance (1 cm) sciatic nerve injury (SNI) through assessments of motor function recovery and neuromuscular structural/functional rehabilitation.

Results: Finite element analysis confirmed stable electromotive force induction in RBC-CNT-SMP conduits under magnetic fields. Combined with magnetic stimulation, the conduit matched autologous graft efficacy. It significantly improved motor recovery in long-distance sciatic nerve injury rats, increasing ground contact time and sciatic function index versus non-autologous controls. Neurologically, it reduced compound motor action potential latency, increased amplitude, and enhanced myelin/axon regeneration. Muscularly, it boosted gastrocnemius wet weight recovery and minimized atrophy and fibrosis.

Conclusion: Our study demonstrates the practical role of electromagnetic induction in nerve repair and opens a window for electromagnetic synergy in peripheral nerve injury restoration.