DEFORMATION OF A LIPID VESICLE IN AN ELECTRIC-FIELD - A THEORETICAL-STUDY

The deformation of a lipid vesicle in an external electric field is analysed assuming constant membrane area and variable vesicle volume due 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 E(0). This ratio is useful for experimental determination of the bending elasticity modulus. The kinetics of vesicle deformation is described by the characteristic relaxation time tau. This time increases drastically with vesicle size. A non-monotonic dependence of tau on E(0) is shown numerically and analytically. For weak and strong fields tau is proportional to E(0)(4) and E(0)(-8/3) respectively.