A Platform for the Actuation of Magnetically Labeled Skeletal Muscle Cells Using Dynamic Magnetic Stimulation

Engineering skeletal muscle tissues with controllable bioactuation is essential for advances in biohybrid robotics, regenerative medicine, and high-fidelity disease models. Mechanical stimulation has been shown to replicate the effects of physical exercise, while magnetic stimulation allows the manipulation of cells in a non-invasive manner. Here, a platform based on Helmholtz coil pair for magnetic stimulation is developed. To focus the stimulation through mechanotransduction, magnetic microspheres (MMS) were conjugated to myoblast integrins at defined MMS-to-cell ratios, functioning as microscale actuators under alternating magnetic fields. Exposure of non-labeled C2C12 cells to ∼2.9 mT, 50 Hz magnetic fields enhanced myogenic differentiation, with significantly increased fusion indices after 10 and 30 min of daily stimulation. Remarkably, MMS-labeled cells (1:1 ratio) required only 2 min of daily stimulation to achieve comparable enhancement, demonstrating the efficacy of targeted microactuation. Mechanistic analysis revealed elevated nuclear localization of Yes-associated protein (YAP) in stimulated MMS-labeled cells, confirming activation of force-dependent signaling pathways. qRT-PCR analysis further supported these findings, showing stimulation-associated upregulation of myogenic genes, particularly in MMS-labeled cells. The integration of cell labeling with dynamic magnetic fields offers new opportunities for remote stimulation strategies in biofabrication, muscle tissue engineering, and therapeutic approaches for muscle tissue.