Reversible Permeabilization of Cancer Cells by High Sub-Microsecond Magnetic Field

Exposure of cells to pulsed electric fields (PEFs) induces a phenomenon known as electroporation, which leads to increase of membrane permeability. Electroporation is applied in biotechnology, food processing, and medicine, including cancer treatment. Recently, a contactless method based on pulsed magnetic fields (PMFs) for the permeabilization of biological cells has been proposed; however, the permeabilization mechanism of the PMF method is still hypothetical. In this paper, we have shown that it is possible to reversibly permeabilize Sp2/0 myeloma cells by sub-microsecond (450 ns) PMF in the range of 0-3.3 T. The PMF methodology was also combined with PEF treatment to evaluate additive effects. The 1.35 kV/cm 1 × 100 μs (PEF) and 3.3 T, 50 pulses, 0.25 Hz (PMF) protocols were applied. The cells were treated in the presence of fluorescence dye YO-PRO-1 and influx into the cells was evaluated by cytometry. Cell viability after the treatment was evaluated by CellEvent Caspase-3/7 assays. A significant (P <; 0.05) additive effect of the two pulsed power methodologies was detected, resulting in up to 12% increase of membrane permeabilization. The PMF method is an emerging technique and the results of the study can be used for the development of new effective protocols, while the determined additive effects with PEF are promising in the field of electrochemotherapy.