Analysis of stability of cylindrical multicomponent vesicles*

Pearling of complex cylindrical fluid threads has been a problem of interest for fluid mechanicians over the last century. More importantly, pearling phenomena of biological vesicles are important to understand the mechanical behavior of cell membranes and other organelles. These vesicles are made up of multiple phospholipids and cholesterol distributed on the membrane surface that give rise to bending resistances. Tubular vesicles can undergo pearling – formation of beads on the liquid threads akin to the Rayleigh Plateau instability. Previous studies have inspected the effects of surface tension on the pearling instabilities of vesicles made up of homogenous phospholipids. However, not much has been discussed about the pearling instabilities in multicomponent vesicles which involve an additional factor, phase separation and domain line tension. In this study, we inspect the linear stability of a cylindrical vesicle with multiple phospholipids on the surface undergoing phase separation and diffusion. We solve the Stokes equations along with the Cahn-Hilliard equations to develop the linearized dynamic equations governing the shape and concentration fields. We delineate the effects of phase separation on pearling and how it aids the process depending on the underlying critical dimensionless variables. This study could be instrumental in understanding a multitude of physical phenomena surrounding cells, organelles, and even active fibers.