Plasma Membrane Charging of Jurkat Cells by Nanosecond Pulsed Electric Fields

With the application of pulsed electric fields of only nanosecond duration but field strengths of several megavolts per centimeter, apoptosis can be induced in tumor cells. The detailed mechanisms of this process are not yet completely understood. The accumulation of charges along the membranes in the applied electric field is likely the primary trigger. This first response is observed as a sudden shift in the plasma transmembrane potential that is faster than can be attributed to any physiological event. These immediate, yet transient, effects are only measurable if the diagnostic is faster than the exposure, i.e. on a nanosecond timescale. In this study, we monitored changes in the plasma transmembrane potential of Jurkat cells exposed to a nanosecond pulsed electric fields (nsPEF) of 60 ns and amplitudes from 5 to 90 kV/cm in real time, i.e. with a temporal resolution of 5 ns* After an initial sudden increase to 1 V, the potential differences at the anodic pole continue to rise at a more moderate rate to ~1.6 V for applied field strengths equal to, or greater than, 50 kV/cm. The subsequent drop in voltage even while the electric field is still applied suggest the formation of pores.