Vesicles in Electric Fields

Abstract

Giant vesicles provide exceptional biomembrane models for systematic studies on the effect of electric fields because the membrane response can be directly visualized under the microscope (1-3). In AC fields, the dependence of the vesicle morphology on both field frequency and media conductivity has been characterized recently (3, 4). The theoretical models for the observed morphological transitions (5, 6) predict the dependence of the frequency of the prolate-oblate transition on the vesicle size. We used this prediction to develop a method for measuring the membrane capacitance (7). At a fixed field frequency and increasing field strength, the degree of vesicle deformation increases and can be used to deduce the membrane bending rigidity (8). Inhomogeneous AC fields trigger flows on the membrane surface visualized by domain movement (9). When exposed to strong DC pulses, giant vesicles porate. Using the dynamics of the pore closure, we developed an approach for measuring the edge tension and evaluate the membrane stability (10). The response of both fluid- and gel-phase membranes will be discussed. We also established an electrofusion protocol for creating multicomponent giant vesicles with precisely known composition and used it to locate tie lines in the region of coexistence of liquid-ordered and liquid-disordered phases (11).1. Dimova, in Advances in Planar Lipid Bilayers and Liposomes, p. 1, Academic Press (2012).2. Dimova et al., Soft Matter, 3, 817 (2007).3. Dimova et al., Soft Matter, 5, 3201 (2009).4. Aranda et al., Biophys. J., 95, L19 (2008).5. Vlahovska et al., Biophys. J., 96, 4789 (2009).6. Yamamoto et al., Langmuir, 26, 12390 (2010).7. Salipante et al., Soft Matter, 8, 3810 (2012).8. Gracia et al., Soft Matter, 6, 1472 (2010).9. Staykova et al., Soft Matter, 4, 2168 (2008).10. Portet and R. Dimova, Biophys. J., 99, 3264 (2010).11. Bezlyepkina et al., Biophys. J., 104, 1456 (2013).