Slippery Multicomponent Vesicles*

Multicomponent vesicles are composed of cholesterol that combine with saturated lipids to form energetically stable domains on the vesicle surface. The presence of different lipid species lead to varying material properties, such as bending rigidity, produce a rich variety of dynamics as seen in experiments. In this work, a three-dimensional model is developed to study multicomponent vesicle dynamics in the presence of an externally driven fluid. The domains on the membrane experience an effective velocity, differing from the surrounding fluid velocity due to the molecular diffusivity of the lipids. Unlike prior modeling efforts, this effective velocity is now considered. The membrane surface is modeled using a two-phase Cahn-Hilliard equation using a level set/closest point method while the membrane is coupled to the surrounding fluid using the energy variation approach. The dynamics observed by this predictive model, influence of material properties and impact of the surface effective velocity will be discussed. We envision applications in measuring surface properties of biological cells and manufacturing of designer vesicles.