Self-organization and hydrodynamics of active rods on fluid membranes

The transport and self-organization of active self-propelled rod-like proteins and biopolymers on the cell membrane is a key component of many cellular processes and functions. Such systems are shown to exhibit a complex range of collective behavior, including aggregation, self-organization, and complex defect dynamics. Here we use a combination of continuum modeling and particle simulations based on slender-body theory to study the collective dynamics of a suspension of pusher and puller rods in a fluid membrane submerged in bulk fluid, as a simplified model for the assembly of cytoskeletal biopolymers on the cell membrane. Specifically, we explore the effect of the ratio of the membrane to bulk fluid viscosities and the aspect ratio of the rods on the generated flows and the orientation and concentration fields of the active rods.