Modelling induced currents in biological cells exposed to low-frequency magnetic fields

Interactions of low-frequency magnetic fields with biological systems have been a subject of intense scientific inquiry and public concern. Most research has been done at powerline frequencies of 50 Hz or 60 Hz. One of the key questions related to interactions of low-frequency magnetic fields with biological systems is which parameters of the exposure field are responsible for observed effects. Knowledge of the induced electric field and current in various experimental in vitro systems is important for this purpose. The 3D impedance method is used in this research to model spatial patterns of induced electric fields and current in two preparations of cells. A cell monolayer with a random distribution of cells and a confluent monolayer of cells with gap junctions are considered; because of the limitations of the computational method, biological cells are represented by cubes rather than more realistic shapes (e.g. spheres). The random model indicates that for higher cell densities the pattern of the induced current flow has a limited dependence on the size and shape of the container in which the cells are placed, it depends mostly on the actual cell placement. Gap junctions, not surprisingly, are shown to increase the current density, but only if their resistance is sufficiently low. The highest current density occurs in the gaps.