A transient solution for vesicle electrodeformation and relaxation

TL;DR

This paper develops a transient model for vesicle deformation under DC electric fields, capturing the dynamics of shape change and relaxation, and revealing a universal scaling law for vesicle relaxation based on physical parameters.

Contribution

It introduces a new transient ODE-based model for vesicle deformation that accounts for membrane mechanics and charging, validated against experimental data.

Findings

Model accurately predicts vesicle behavior in weak electroporation regimes.

Vesicle relaxation follows a universal timescale independent of deformation method.

The universal law relates relaxation time to vesicle radius, viscosity, and membrane tension.

Abstract

A transient analysis for vesicle deformation under DC electric fields is developed. The theory extends from a droplet model, with the additional consideration of a lipid membrane separating two fluids of arbitrary properties. For the latter, both a membrane-charging and a membrane-mechanical model are supplied. The vesicle is assumed to remain spheroidal in shape for all times. The main result is an ODE governing the evolution of the vesicle aspect ratio. The effects of initial membrane tension and pulse length are examined. The model prediction is extensively compared with experimental data, and is shown to accurately capture the system behavior in the regime of no or weak electroporation. More importantly, the comparison reveals that vesicle relaxation obeys a universal behavior regardless of the means of deformation. The process is governed by a single timescale that is a function of the vesicle initial radius, the fluid viscosity, and the initial membrane tension. This universal scaling law can be used to calculate membrane properties from experimental data.