Calculations of Cell Transmembrane Voltage Induced by Time-Varying Magnetic Fields

Electric pulses can create pores and/or render cell membranes permeable, and this effect has been studied for decades. Applications include cell membrane permeabilization for gene electrotransfer, drug delivery, and related electrochemotherapy, as well as tissue ablation. Here, we probe the use of time-varying magnetic fields to modulate the transmembrane voltage (TMV) across cell membranes through numerical simulations. This could be a contactless, noninvasive technique. Results show that the induced TMV values exceeding the 1 V threshold for electroporation could be achieved for short duration pulsing with fast rise and fall times. The strongest response is then predicted to occur when the lateral distance between a cell and the center of a current carrying coil equals the coil radius. The induced TMV is shown to peak when the gradient in the magnetic potential is the largest. However, with the more realistic but longer microsecond pulse stimulation systems, the induced TMV is much smaller. Hence, developing shorter pulses or fast rise times is critical for achieving membrane poration based on time-varying magnetic fields. Other effects could also focus on the use of nanoparticles (including magnetic materials) for possible heating for synergistic enhancements of transport through tumor cell membranes.