Magneto-responsive piezoelectric CoFe₂O₄-PVDF system for on-demand electrical modulation of infarcted myocardium

Myocardial infarction (MI) disrupts myocardial electrical conduction and contractile function, causing irreversible cardiac dysfunction. Piezoelectric materials offer great potential for MI repair via in situ electrical generation. However, traditional ultrasound-triggered piezoelectric activation inevitably induces local hyperthermia and secondary myocardial damage. Additionally, the piezoelectric therapeutic mechanisms for cardiac therapy remain poorly understood. Herein, we innovatively fabricated a magneto-responsive, self-powered CoFe₂O₄-PVDF composite therapeutic system. This composite achieves on-demand electrical modulation via non-invasive magnetic stimulation: CoFe₂O₄ generates magnetostrictive strain under magnetic actuation, which is efficiently converted into functional piezoelectric charges by PVDF, thereby enabling safe, spatiotemporally controllable in situ cardiac electrical stimulation. In vivo results confirmed that the system significantly improved cardiac ejection fraction and reduced myocardial fibrosis. It upregulated key genes governing angiogenesis, calcium signaling, and cardiomyocyte proliferation. In vitro, the composite promoted hypoxic H9c2 cardiomyocyte spreading and suppressed apoptosis under magnetic stimulation. First-principles calculations further verified that CoFe₂O₄ optimizes the electronic state density of PVDF and enhances its charge output, revealing the synergistic mechanism. This work establishes an innovative magneto-driven, on-demand electrical therapy platform to overcome the limitations of conventional piezoelectric treatment. It provides novel mechanistic insights and a translational strategy for efficient MI repair via precise in situ regulation of the myocardial electrical microenvironment.