Shape dynamics and lipid hydrodynamics of bilayer membranes
Mohammad Rahimi (), Marino Arroyo (UPC-BarcelonaTech)
Computational Mechanics of Biomembranes
Mon 9:00 - 10:30
Barus-Holley 160
Biological membranes are continuously brought out of equilibrium, as they shape organelles, package and transport cargo, or respond to external actions. Even the dynamics of plain lipid membranes in experimental model systems are very complex due to the tight interplay between the bilayer architecture, the shape dynamics, and the rearrangement of the lipid molecules. We formulate and numerically implement a continuum model of the shape dynamics and lipid hydrodynamics, which describes the bilayer by its midsurface and by a lipid density field for each monolayer. The viscoelastic response of bilayers is determined by the stretching and curvature elasticity, and by the inter-monolayer friction and the membrane interfacial shear viscosity. While the bilayer equilibria are well-understood theoretically, dynamical calculations have relied on simplified continuum approaches of uncertain transferability, or on molecular simulations reaching very limited length and time scales. Our approach incorporates the main physics, is fully nonlinear, does not assume predefined shapes, and can access a wide range of time and length scales. We use this model to examine the dynamics of confined bilayers, of bilayers exposed to stimuli changing locally the lipid density, or to study the mobility of inclusions and the fluctuations in curved membranes.