Measurement Of Mechanical Parameters Of Lipid Bilayer Form The Deformation Of Membrane Nanotube In Electric Field

Abstract

The effect of a longitudinal electric field on the shape of a lipid nanotube formed in an electrolyte solution is considered experimentally and theoretically. Application of a moderate (50-250mV) potential difference between two ends of the nanotube caused the tube expansion so that its shape deflected from the initial cylindrical to the parabolic one. The magnitude of this deviation depends on 1) the potential difference applied, 2) initial lateral tension and 3) bending modulus of the nanotube membrane. This deviation can be quantified as an effective radius of the nanotube determined by the mechanical parameters of the nanotube membrane and the magnitude of the applied electrical field. From the dependence of this radius on the potential difference the values of both lateral tension and bending rigidity of the nanotube membrane can be extracted. The obtained results are in good agreement with the data reported by different techniques for similar lipid compositions. Hence the electric field can be utilized for measurement of mechanical parameters of tubular membrane, specifically, short and/or narrow tubules which are not readily accessible by conventional techniques.