Electrically Stimulated Membrane Breakdown

Abstract

The first sign of cell exposure to electrical pulses (strength in Kilovolts per Centimeter and duration in microseconds to milliseconds) is loss of the membrane permeation barrier against ions and small molecules. These permeability changes may be rapidly reversible or irreversible depending on the intensity and the width of the electrical pulses, as well as the composition of the suspending medium. After the rapid increase of the membrane permeability, many delayed effects of the electrical stimulation are observed. These slower secondary effects include membrane fusions, membrane bleb formation, endocytotic reactions, reorganization of the cytoskeletal network, and, in severe cases, lysis of the cells. Global membrane rupture and cell death are mainly due to these secondary effects. Cell death may be prevented by following certain protocols, the most crucial of which is to balance the osmotic pressure of the cytoplasmic fluid and the extracellular medium. Experiments show that electrical stimulation introduces pores of limited sizes in the plasma membrane. These pores can be resealed without losing the cytoplasmic macromolecular contents, and most cells will survive after pore resealing. Electroporation has found many applications in molecular biology, genetic engineering, agricultural research, and biotechnology.