Diffusive and Enzymatic Modulation of the Dynamic Size Distribution of DNA Droplets

We investigate how material diffusion processes affect the temporal evolution of the radii of DNA droplets formed from DNA nanoparticles whose phase-separation ability can be enzymatically degraded. The droplets are immobilized so as to disallow Brownian coalescence, and their size is tracked using confocal fluorescent microscopy. Without enzymes, we observe very slow Ostwald ripening in rough agreement with the Lifshitz-Slyozov-Wagner theory. With enzymes, we observe a dynamic radius distribution in which time and radius decouple, leading to an unusual behavior in which the average radius remains constant despite the total droplet volume decreasing. Our Letter provides insights into the statistical dynamics of phase-separated droplets, with relevance to both biological condensates and materials applications.