Cell Membrane Electropermeabilization

Abstract

The behavior of cell membranes can be strongly affected when pulsed electric fields are delivered on a cell culture. Fields can be applied either continuously or during a short duration (electric pulse). Electropulsation results in the cell membrane permeabilization. Electropermeabilization is one of the most successful methods to introduce foreign molecules in living cells in vitro or to assist the extraction of high value compounds from microorganisms and from plant cells. The treatment is observed to be lethal. Death of the organisms is not due to the products of electrolysis; the temperature rise of the suspension is too small and short-lived to cause lethality. Many physical effects of the field pulse can be observed in the cell. From the dielectric properties of the cell membrane, it is proposed that the field modulates the transmembrane potential of cells. The induced potential triggers conformational changes in the membrane structure when it is larger than a critical value. These structural changes result in the observed loss of the cell's permeability barrier properties. The level of membrane alteration is observed to increase with the pulse length and number of pulses, and by the field strength in the suspension. The molecular processes are complicated and remain poorly characterized. Membrane damage is demonstrated by the lysis of protoplasts, the leakage of intracellular contents, and the loss of the ability of Escherichia coli to plasmolyze in a hypertonic medium