Flagellar dynamics of a connected chain of active, Brownian particles

Abstract

Eukaryotic flagella are active structures with a complex architecture of microtubules, motor proteins and elastic links. They are capable of whiplike motions driven by motors sliding along filaments that are themselves constrained at an end. Here, we show that active, self-propelled particles that are connected together to form a single chain that is anchored at one end can produce the graceful beating motions of flagella. We use a combination of numerical simulations, scaling analysis and mean field continuum elastic theory to demarcate the phase diagram for this type of oscillatory motion as a function of the filament length, passive elasticity, propulsion force and longitudinal persistence of propulsion directions. Depending on the nature of the anchoring, we show that filament either undergoes flagella-like beating or assumes a steadily rotating coiled conformation. Our system is simpler than its biological inspiration, and thus could be experimentally realized using a variety of self-propelled particles.