Dissolving a DNA liquid through competition

Coacervation plays a key role in spatial and temporal organization within the cell. Short nucleic acids are one mechanism that has been shown to control the intracellular dense liquids (e.g., introducing or removing short nucleic acids causes changes in the properties and appearance of droplets.) Here, we employ a model DNA liquid system and quantify the dissolution by short nucleic acids. Previous work has confirmed that this system is similar to intracellular droplets in terms of physical properties and spatial control (i.e., specific molecules are enriched or depleted in the droplet phase). The liquid is comprised of DNA in the shape of a 4-armed nanostar with each arm ending in a palindromic sequence that allows nanostars to interact and condense into droplets. By incorporating a toe-hold sequence on the nanostar, short hairpins are able to outcompete the nanostars for interaction sites causing the droplets to dissolve. Using confocal microscopy, we track DNA liquid break-up and compare the rate of decay to hairpin-nanostar interaction strength, concentration of the hairpin, and toehold location. This work will give insight into the different mechanisms that drive coacervate dissolution.