Effect of externally applied electric field on lipid monolayers at the air-water interfase

. WILKE, B. MAGGIO, SA DASSIE, EPM LEIVA

Actas de la Academia Nacional de Ciencias

Año: 2007 p. 123 - 123

0325-7533

font face="Times-Roman" size="2"> Lipid and protein molecules anisotropically oriented at a hydrocarbon-aqueous interface configure a dynamic array of selforganized molecular dipoles. Electrostatic fields applied to lipid monolayers have been shown to induce in-plane migration of domains or phase separation in a homogeneous system. In this work, we have investigated the effect of externally applied electrostatic fields on the distribution of the condensed ceramide-enriched domains in mixed monolayers with sphingomyelin. In these monolayers, the lipid segregates in different phases at all pressures. This allows analyzing by epifluorescence microscopy the effect of the electrostatic field at all lateral pressures since dark domains are always present. Our  observations indicate that a positive potential applied to an electrode placed over the monolayer induces lateral displacements of the dark-condensed domains from the electrode perturbed region. The effect is rat