ИСТИНА

The theory of elasticity of lipid membranes is an important tool used for the theoretical description of processes of cell membrane remodelling. The classic Helfrich functional of elastic energy of lipid membrane is quadratic on the deformations and derived under the assumption of small deformations. Recently, molecular dynamics researches challenged the validity of the linear model, questioning the constancy of the bending modulus at high curvatures. Analyzing both cylindrical and parabolic deformations realized in molecular dynamic simulations, we have demonstrated the applicability of the quadratic Helfrich elastic model, if it is used separately to obtain the energy of each membrane leaflet. We confirmed theoretical results experimentally, additionally proving that the elastic energy of two lipid monolayers is additive. Furthermore, we found that membrane bending stiffness can be decreased twofold by the addition of a low molecular weight solvent to the lipid mixture. We attribute this effect to incorporation of solvent molecules in between the lipids of the inner monolayer, to relax the curvature stress. The study supported by RSCF grant No.19-74-00152.