Magnetic-driven wireless electrical stimulation in a scaffold

Electrical stimulation was constrained in commonly requiring a complicated wiring and external power source, despite its ability in modulating cellular functions in tissue repair. Herein, a wireless electrical stimulation system was constructed by taking advantage of magnetoelectric coupling effect. Specifically, piezoelectric BaTiO3 (BT) was in-situ grown on magnetostrictive CoFe2O4 (CFO), forming core-shell structured nanoparticles. Among them, CFO core enabled to generate strain in response to external magnetic field as a result of the shift and rotation of magnetic domains. The generated strain transferred to BT shell through interface coupling, compelled the reversal of BT domain, and eventually induced the generation of electrical signals, thereby constructing a noninvasive electrical stimulation system. Therefore, electrical stimulation system was incorporated into polymer scaffolds. Encouragingly, under the excitation of magnetic field, the scaffold exhibited a magnetoelectric coupling coefficient about 10 mV/cm*Oe and bring a voltage of 100 mV/cm, which was in appropriate electrical stimulation range (50–150 mV/cm). The results demonstrated that electrical signals effectively promoted cell proliferation and differentiation, and up-regulated genes expression including Col-I, OCN and Runx2. These findings light up possibility of wireless electrical stimulation for bone repair in future.