Reversible electrical breakdown

Chernomordik, L.V., Pastushenko, V.F., and Sokirko, A.I. (1988) Reversible electrical breakdown of lipid... 

In contrast, pore models consider the pore-expanding forces that are parallel to the membrane and that arise from normal forces acting on pores as U is increased. Pore models can quantitatively account for both rupture and reversible electrical breakdown (REB) in planar membranes and reversible behavior in cells. For this reason, our discussion will emphasize localized electroconformational changes, particularly hydrophilic pores. The modeling of electroporation using such pores was first presented in an impressive series of seven back-to-back papers only the first paper is cited here (10). 

Reversible electrical breakdown (REB) is particularly striking. (REB is actually a rapid discharge due to the high ionic conductivity caused by the gentle structural membrane rearrangement of multiple pore formation.) In our models, subcritical pores (i.e., nonrupture-causing pores) are responsible for this high conductance state (II). Our first quantitative description of REB (33, 34) correctly predicted many key features of U(t) and G(t) but had... 

Reversible electrical breakdown (REB) is caused by large ionic conduction through... 

Figure 1A. Short time scale (0-1 pus) behavior of the transmembrane voltage [U(t)] predicted by a recent version of the theoretical model for a planar bilayer membrane exposed to a single very short (0.4-fis) pulse that is, charge injection conditions (16). The key features of reversible electrical breakdown (REB) are predicted by the model, as is the occurrence of incomplete reversible electrical breakdown. In the case of incomplete reversible electrical breakdown, the membrane discharge is incomplete because U(t) does not reach zero after the pulse. Each curve is labeled by the corresponding value of the injected charge Q. The curves for Q = 25 and 20 nC show REB, whereas the other...

Chang, D.C., 1989. Cell poration and cell fusion using an oscillating electric field. Biophys. J. 56, 641—652. Chemomordik, L.V., Sukharev, S.I., Abidor, I.G., Chizmadzhev, Yu.A., 1982. The study of the BLM reversible electrical breakdown mechanism in the presence of UO2. Bioelectrochem. Bioenerg. 9, 149—155. Chilcott, T.C., Coster, H.G.L., 1991. AC impedance measurements on Chara Corallina. 1 Characterization of the static cytoplasm. Aust. J. Plant Physiol. 18 (2), 191—199. 

About 10 years ago, a new, easy and versatile technique for the introduction of larger macromolecules into eukaryotic and prokaryotic cells was established (Neumann et al., 1982 Knight, 1981) it is now commonly known as electroporation (Weaver, 1993). It is mainly a physical process, based on the transient permeabiliza-tion of cell membranes by pulses of sufficiently high electric fields. The underlying membrane phenomenon, called reversible electrical breakdown (REB) followed by transient pore formation, occurs if the transmembrane potential reaches values of 0.5 -1.5 V. Membrane pores are generated and molecules are transported through these pores by diffusion, electrical drift, and electroosmosis. Electroporation seems to be a rather universal process in most natural membranes. 

Benz, F. Beckers, and U. Zimmermann, Reversible electrical breakdown of lipid bilayer membranes a charge-pulse relaxation study,... 

Reversible electrical breakdown of lipid bilayers Formation and evolution of pores. Biochim. Biophys. Acta 940 275-287. 

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The other factor which makes liquid insulators so attractive is the reversibility of the changes caused by the electrical breakdown phenomenon, i.e., structural and chemical changes of the material. In practice, the liquid dielectrics may be used repetitively for electrical energy storage devices. 

This model raises the question of the dependence of the electrical breakdown potential on the electronic work function of the electrodes. At a first approximation one could conclude that a lower breakdown voltage will be observed for the cathodes with lower electronic work function (less voltage is required to bring the Fermi level to the conduction band of solvent cf. Fig. 31), but this is not true (Fig. 30). To explain this discrepancy, we recall the effect of the rate of the electrochemical reaction on the breakdown potential (Fig. 29), which is the reverse of the changes in the electronic work function of the electrode material. The changes... 

Electroporation. When bacteria are exposed to an electric field a number of physical and biochemical changes occur. The bacterial membrane becomes polarized at low electric field. When the membrane potential reaches a critical value of 200—300 mV, areas of reversible local disorganization and transient breakdown occur resulting in a permeable membrane. This results in both molecular influx and efflux. The nature of the membrane disturbance is not clearly understood but bacteria, yeast, and fungi are capable of DNA uptake (see Yeasts). This method, called electroporation, has been used to transform a variety of bacterial and yeast strains that are recalcitrant to other methods (2). Apparatus for electroporation is commercially available, and constant improvements in the design are being made. 

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