Frequency-dependent electrodeformation of giant phospholipid vesicles in AC electric field

TL;DR

This paper presents a model for vesicle electrodeformation in AC electric fields, accurately predicting shape transitions and explaining experimental phase diagrams based on frequency and conductivity ratios.

Contribution

The model uniquely combines membrane bending energy and electric field energy, achieving quantitative agreement with experiments and explaining shape phase diagrams.

Findings

Good agreement with prolate-to-oblate transition frequencies

Explains vesicle shape phase diagram with frequency and conductivity ratio

Suggests applications in conductometry of small samples

Abstract

A model of vesicle electrodeformation is described which obtains a parametrized vesicle shape by minimizing the sum of the membrane bending energy and the energy due to the electric field. Both the vesicle membrane and the aqueous media inside and outside the vesicle are treated as leaky dielectrics, and the vesicle itself is modelled as a nearly spherical shape enclosed within a thin membrane. It is demonstrated (a) that the model achieves a good quantitative agreement with the experimentally determined prolate-to-oblate transition frequencies in the kHz range, and (b) that the model can explain a phase diagram of shapes of giant phospholipid vesicles with respect to two parameters: the frequency of the applied AC electric field and the ratio of the electrical conductivities of the aqueous media inside and outside the vesicle, explored in a recent paper (S. Aranda et al., Biophys. J. 95:L19--L21, 2008). A possible use of the frequency-dependent shape transitions of phospholipid vesicles in conductometry of microliter samples is discussed.