Analysis of stability of cylindrical multicomponent vesicles

Multicomponent vesicles are sacs of fluid containing multiple phospholipids and cholesterol molecules on the lipid bilayer. The lipid bilayer can phase separate into ordered/disordered domains that give rise to inhomogeneous bending resistances and line tension between domains. These systems give rise to a richer set of hydrodynamic instabilities than simple fluids and single component vesicles. In this study, we inspect the linear and non-linear stability of a multicomponent, cylindrical vesicle by solving the Stokes equations along with the Cahn-Hilliard equations. We delineate the effects of phase separation on pearling and how it aids the process depending on the underlying critical dimensionless variables. We determine the conditions under which axisymmetric and non-axisymmetric modes are unstable and supplement our results with an energy analysis that shows the sources for these instabilities. We provide a comparison between linear and weakly-nonlinear dynamics in this study to shed light on the coarsening dynamics and the dependence on physical parameters. Moreover, we share a qualitative comparison with previous experiments. This study could be instrumental in understanding a multitude of physical phenomena surrounding cells, organelles, and even active fibers.