The Effect of the Electric Field on the Shapes of Phospholipid Vesicles

The shapes of phospholipid vesicles in an external electric field are evaluated using the bilayer couple model of the phospholipid membrane. Nearly spherical vesicles have for small fields a shape of prolate ellipsoids, which get more elongated with increasing electric field. For larger fields the elongation does not increase simply, but a bulge starts to grow on the equator. The shapes which minimize the membrane bending energy at given membrane area are calculated in dependence of the electric field and the corresponding volumes are determined.