Eur. Phys. J. E (2015) 38: 112
https://doi.org/10.1140/epje/i2015-15112-6

Regular Article

Complex instability of axially compressed tubular lipid membrane with controlled spontaneous curvature

¹ Faculty of Physics, Southern Federal University, 5 Zorge Street, 344090, Rostov-on-Don, Russia
² Laboratoire Charles Coulomb, UMR 5221 CNRS, Université de Montpellier, Place E. Bataillon, F-34095, Montpellier Cedex 5, France

^* e-mail: vaniagolushko@yandex.ru

Received: 6 July 2015
Revised: 20 August 2015
Accepted: 13 October 2015
Published online: 29 October 2015

Abstract

Tubular lipid membranes (TLMs) are formed by an external pulling force from artificial or biological bilayer vesicles and can be subsequently stabilized by incorporating proteins or amphiphilic polymers into the lipid bilayer. The arising spontaneous curvature of the lipid sheet allows switching off the pulling force without TLM destabilization. However, here we show that during this process two different thermal fluctuation modes drastically increase their amplitudes making fluctuations of the TLM much greater than its radius. Due to the system’s proximity to the critical fluctuation point, a weak axial compressive force is sufficient to destabilize the TLM. Its absolute value is shown to be much smaller than that of the pulling force required for the initial lipid nanotube formation. Induced complex instability was studied in the frame of Landau phase transition theory. The process involves two consecutive second-order phase transitions and leads to the tube deformation combining annular corrugation with completely unconventional chiral buckling.