The Growth Rate of DNA Condensate Droplets Increases with the Size of Participating Subunits

The bottom-up synthesis of biomolecular condensates with simple constituents, like nucleic acids and peptides, is supporting the development of new amorphous materials. Understanding which parameters determine condensate growth kinetics is important for the synthesis of condensates with the capacity for active, dynamic behaviors. Here we use DNA nanotechnology to study artificial liquid condensates through programmable star-shaped subunits, focusing on the effects of changing subunit size. First, we show that condensation is achieved in a 6-fold range of subunit size. Second, we demonstrate that the rate of growth of condensate droplets scales with subunit size. Our investigation is supported by a general model that describes how coarsening and coalescence are expected to scale with subunit size under ideal assumptions. Beyond suggesting a route toward achieving control of condensation kinetics via design of subunit size in synthetic liquids, our work suggests that particle size may be a key parameter in biological phase separation.