The Influence of Magnetothermal Stimulation on Viability of Cells in 2D Cultures and 3D Magnetic Collagen Gels

Magnetic nanoparticles (MNPs) hold great promise for bioelectronic medicine, particularly as transducers of remote activation to control cell function. MNPs in the 20-30 nm size range efficiently dissipate heat under alternating magnetic fields (AMFs), enabling control of heat-sensitive receptors that regulate electrogenic cell signaling. However, effective magnetothermal stimulation tools must maintain cell viability and optimally deliver heat to the cellular microenvironment. Moreover, improved in vitro models, particularly 3D cultures that better mimic the cell microenvironment, are needed to assess magnetothermal stimulation before transitioning to in vivo demonstrations. This study examined cell viability under AMF conditions with different heating rates and stimulation durations. In addition, a tunable magnetic collagen gel is developed to support magnetothermal stimulation while allowing control over heat dissipation and mechanical properties by adjusting MNP concentration inside the gel. Cells embedded within the stimuli-responsive magnetic gel exhibited proliferation and cytoskeletal organization, suggesting its suitability as a biological implant. These findings advance the design of magnetothermal stimulation systems and pave new avenues for bioelectronic medicine, including the integration of magnetic implants in cell therapies.