Growth and division of chemically active droplets: A model for protocells

Macromolecular phase separation and droplet formation have long been proposed as key elements in the formation of protocells during the origin of life. A simple model of a protocell consists of a droplet, where droplet material is produced outside the droplet, and chemical reactions inside the droplet play the role of a simple metabolism. Our theoretical study shows that such chemically active droplets can have a flux-driven shape instability that leads to a symmetric droplet division. We analyze the dependence of the instability on the droplet viscosity and parameters that characterize the metabolism and material production. Our work provides a physical mechanism for the division of early protocells before the appearance of membranes.