Piezoelectric Surface Charge and Dynamic Stimulation Synergize to Promote Cardiac Myoblast Alignment and Maturation

This work investigates the role of surface charge and synergistic mechano-electrical stimulation of piezoelectric poly(vinylidene fluoride) (PVDF) on the behaviour of H9c2 cardiac cells. H9c2 cells preferentially adhered to poled PVDF samples, regardless of polarity, indicating that increased average surface charge creates a favourable environment for initial attachment. Proliferation assays showed that negatively charged PVDF films promote the highest early growth, while dynamic mechanical stimulation (1 h/day) further enhanced proliferation, particularly on positively poled PVDF, highlighting a synergistic effect between charge and mechanical cues. Differentiation assays demonstrated that stimulation applied during either the proliferation or differentiation phase promoted myotube formation, increasing length, width, and alignment, with negatively poled PVDF supporting the most advanced maturation. At the molecular level, qPCR confirmed upregulation of the early cardiomyogenic marker actc1, whereas the late marker Tnnt2 remained unchanged, indicating partial but incomplete cardiomyocyte differentiation. These results reveal that both static polarization and dynamic piezoelectric stimulation cooperatively modulate cell fate decisions, integrating electrical and mechanical signalling pathways. Together, these findings demonstrate that surface polarization and mechano-electrical cues of piezoelectric biomaterials act in concert to regulate cardiomyoblast adhesion, proliferation, and differentiation, unveiling charge-dependent design principles for multifunctional electroactive materials aimed at cardiac tissue regeneration.