Piezoelectric-Conductive Microcarrier Combined with Ultrasonic Driven Electrical Stimulation to Promote Sciatic Nerve Regeneration.

Electrical stimulation from electroactive bioma0terials is indispensable for peripheral nerve regeneration, but traditional invasive methods carry infection risks. Non-invasive techniques based on ultrasound and piezoelectric materials provide new solutions to this challenge. In this study, polydopamine (PDA) was used to surface-modify barium titanate nanoparticles (BTNPs), which were then combined with chitosan (CS) microcarriers to successfully fabricate composite microcarriers (BTNP@PDA/CS) with piezoelectric-conductive dual electroactivity for sciatic nerve defect repair. BTNP@PDA/CS piezoelectric microcarrier has good charge transfer ability and electrochemical stability. Under ultrasonic stimulation (US), it has good piezoelectric effect and ultrasonic response characteristics, and the output voltage can be controlled by the ultrasonic power. The results of cell experiment under in vitro ultrasonic electrical stimulation showed that it has a positive effect on promoting macrophage M2-type polarization and the elongation of PC12 cells. The results of animal experiments showed that the combination of piezoelectric microcarriers loaded with rBMSCs and US had anti-inflammatory effects on sciatic nerve defects in rats, accelerated nerve regeneration, and promoted the recovery of nerve motor and conduction functions as well as the recovery of nerve innervation target organs. In summary, the piezoelectric conductive microcarriers leverage ultrasound-driven in situ electrostimulation, offering a synergistic therapeutic strategy for nerve regeneration.