Pulsed electric field induced dielectric evolution of mammalian cells

Pulsed electric field with duration and amplitude over a certain threshold can permeabilize live mammalian cells and trigger various bioelectric effects. These conformational and functional changes lead to modifications in the dielectric characteristic of corresponding cellular structures. Hence, time-resolved measurement of cellular dielectric parameters following exposures to pulsed electric field helps to understand the underlying interaction mechanisms. In this study, we have recorded the dielectric evolution of Jurkat cells, a malignant human T-cell line, induced by exposure to nanosecond and mircosecond pulsed electric fields using time domain dielectric spectroscopy. Cell suspensions were exposed to 8 pulses of 100 μs, 300 ns and 60 ns duration with different amplitude. By combining the Maxwell-Wagner mixture model and a double shell cell model, we observed increases in conductivities of plasma membrane and nuclear envelope after exposure to 300-ns pulses, indicating that intracellular structures had been affected by nanosecond pulses. A strong correlation was found between the plasma membrane conductivity 30 minutes after exposure and the long term cell survival 24 hours after exposure, suggesting the possibility of employing dielectric spectroscopy as a noninvasive means to evaluate and predict the efficacy of pulsed electric field treatment.