Bioelectrochemisry and Bioenergetics. 34 ( 1994) 101 - 107

Deformation of a lipid vesicle in an electric field: a theoretical study

A. Sokirko 1, V. Pastushenko2, S. Svetina3 and Ž i e kš 3

1 Department of Chemistry, Trent University, Peterborough K9J 7BR Ontario (Canada)

2 Institute of Biophysics, J. Kepler University of Linz, Altenbergerstr. 69, A-4040 Linz-Auhof (Austria)

3 Institute of Biophysics, Medical Faculty and J. Stefan Institute, University of Ljubljana, Lipičeta, 61105 Ljubljana (Slovenia)


The deformation of a lipid vesicle in an external electric field is analyzed assuming constant membrane area and variable vesicle volume doe to water transport through the membrane. The shape of the vesicle is approximated by a rotational ellipsoid. The equilibrium ratio of the semi-axes varies monotonically with field strength E0. This ratio is useful for experimental determination of the bending elasticity modulus. The kinetics of vesicle deformation is described by the characteristic relaxation time t. This time increases drastically with vesicle size. A non-monotonic dependence of t on E0 is shown numerically and analytically. For weak and strong fields tis proportional to E04 and E0-8/3 respectively.