Nanosecond electric pulse induced changes in cell suspension conductivity

Electric pulses (EPs) can permeabilize cell membranes and intracellular organelles for ion and molecule transport. One can modulate these biophysical effects by changing the pulse shape and duration. Electrically, EPs change the permittivity and conductivity of the cell membrane and intracellular structures; however, measuring these parameters during the EPs is challenging. We assess the impact of EPs on extracellular conductivity to assess membrane permeabilization and ion transport into or out of the cells. For low conductivity buffer solutions, the extracellular conductivity increases from ~0.15 S/m to 1.1 S/m during 300 ns EPs, indicating membrane pore formation and ion motion out of the cell. For buffer conductivity on the order of the intracellular conductivity, extracellular conductivity changes from ~1.8 S/m without cells to ~1.6 S/m, suggesting much less ion flow. The implications of these results are discussed.