Active self-organization and division of nematic droplets*

Recently, experiments have shown that actin filaments which self-organize into tactoids can be deformed and divided by myosin motors. We present a continuum model that accounts for the activity of myosin motors that slide actin filaments according to their polarity. Using simulations and analytical arguments, we demonstrate how our model captures the essential dynamics and morphology observed in experiments. First a single tactoid is formed, then myosin motors bind, accumulate within the tactoid and localize in the droplet midplane. The myosin motors enable the formation of an aster in the tactoids center, which causes the tactoid to deform into two tactoids with myosin motors at their connecting center. By increasing activity we show how a tactoid can fully divide into two and that multiple asters can emerge inside a droplet, dividing it into three daugter tactoids.