The Influences of Electric Fields on Lipid Membranes

Abstract

When phospholipid membranes are exposed to electric fields a variety of phenomena can be observed, such as phase separation, domain movement, electroporation, -deformation, -fusion, and -striction to name but a few. Understanding such responses is of both fundamental interest as well as of practical application. Various thermodynamic susceptibilities of lipid membranes increase strongly in the melting transition, leading to large changes in, for instance, membrane conductivity, compressibility, bending elasticity, relaxation time, and geometry. Another such property (susceptibility) of the membrane is its electrical capacitance. In the phase transition both area and thickness change significantly, but also the dielectric coefficient can increase due changes in membrane composition. This coupling of the membrane's capacitance to its phase state implies that transient currents will appear if the membrane is pushed into the phase transition by changes in e.g. pH, membrane potential, pressure or temperature. On this poster we will show some of these phenomena, and discuss them in the context of the recently proposed soliton model of nerve signal propagation by Heimburg and Jackson, where the coupling between the electrical aspects and the phase state of the system is of central importance.