Pulsed electric field induced changes in dielectric properties of biological cells

The initial response of a cell to an applied electric field is determined by its dielectric properties. Conversely, exposure to an electric field can alter these parameters. Hence, an understanding of dielectric membrane phenomena helps in explaining the underlying interaction mechanisms. Moreover, different electrical characteristics might also allow devising exposure conditions for pulsed electric field treatments that can preferentially target specific cells, such as tumor cells. Using time domain reflectometry dielectric spectroscopy, we have investigated the dielectric properties of Jurkat cells, a malignant human T-cell line, before and after application of microsecond and nanosecond pulsed electric fields. For microsecond exposures, the conductivity of a cell suspension is expected to increase dramatically following pulse application, suggesting that membrane poration has occurred. For nanosecond-duration pulses, our measurements indicate that changes in the dielectric properties of nuclear envelope, and nucleoplasm are more pronounced than for microsecond pulse duration, implying that intracellular structures are more responsive to shorter pulses.