Real time measurements of cell suspension conductivity changes due to pulsed electric fields

Pulsed electric fields (PEFs) may interact with the cell and/or intracellular membranes depending upon the pulse duration and rise time. The resulting modifications in cell structure and function may be observed through changes in the electrical properties of the cell suspension or of the individual components of the cell, such as the cell membrane, cytoplasm, nuclear envelope, and nucleoplasm. Some past experiments have used time domain dielectric spectroscopy (TDDS) to measure the changes induced by PEFs; however, TDDS cannot be used to measure real time changes since the PEF´s high voltage would damage the sensitive measurement electronics. Thus, we extend previous cell suspension conductivity measurements by measuring the voltage and current across a cuvette during single or multiple pulses and calculating the resulting cell suspension conductivity. Additionally, this approach will enable the use of standard electroporation buffers (e.g. Hank´s Balanced Salt Solution) that have higher conductivities than can be used in TDDS due to electrode polarization. Implications of membrane permeabilization, buffer conductivity, and pulse parameters on PEF induced cell suspension conductivity changes will be discussed.