Liquid Metal-Based Conductive Nerve Guidance Conduit Combined With Electrical Stimulation Boosts Peripheral Nerve Repair

The combination of nerve guide conduits (NGCs) and electrical stimulation (ES) is an effective treatment for peripheral nerve injury (PNI). Flexible conductive materials with mechanical properties similar to those of biological tissues have been shown to have better long-term biointegration and functionality than rigid conductive materials. In this study, liquid metal (LM)-based conductive polycaprolactone/gelatin/polypyrrole/LM (PCL/Gel/PPy/LM, PGPL) NGC was combined with exogenous ES to repair PNI. PGPL membranes had good hydrophilicity, degradability, and mechanical properties, and its conductivity reached 0.66 ± 0.02 S/m. In vitro studies showed that the combination of PGPL membranes and ES (2 Hz, 100 mV/cm, 30 min/d) could significantly increase the expression of neuromarkers and had a better pro-neural differentiation effect. In vivo studies demonstrated that PGPL NGCs in combination with ES (2 Hz, 200 mV/mm, 30 min/d) could effectively promote morphological reconstruction and functional recovery of the sciatic nerve in rats. At 3 months post-surgery, PGPL NGCs combined with ES restored the nerve conduction velocity to 73.85% ± 5.45% of the normal value. The LM-based NGCs prepared in this study could effectively repair long sciatic nerve defects, which may further expand the application of LM in the field of nerve tissue engineering.