Critical electric field and transmembrane voltage for lipid pore formation in experiments

Abstract

Electropermeabilization is the result of exposure of cells to electric field pulses. The field pulse lasts from submicro- to several milliseconds. The field intensity should be large enough to induce a dramatic structural local alteration of the cell membrane organization. This results in transiently increased permeabilization of the target cell membrane. Due to the dielectric properties of the cell membrane, the external field induces a transmembrane voltage (TMV) which is controlled by size distribution in a population of cells. In most experiments, permeabilization is detected only when cell is exposed to a critical field strength. This is associated to a critical TMV that affects a subpopulation among the treated cells. This chapter describes the approaches to associate external field and induced TMV. The definition of the critical TMV is discussed. The different assays (conductance, transport) are described with the critical consideration of their sensitivity for the definition of a threshold. The resulting different estimations of the critical TMVare then reported for the different assays and systems. The information provided by lipid assemblies, the simplest system, is then described as a guide for the effects of chemical and biochemical modifications of cell membranes. But the final conclusions remain that cell membrane electropermeabilization is indeed a complex process and its molecular characterization remains an intense field of investigations.