Facile engineering of droplet-in-droplet structures using DNA nanostars

Biological condensates, notably the nucleolus, display droplet-in-droplet morphologies due to the magnitude of interfacial tensions between the various pairs of phases. Here, we investigate the ability to engineer artificial condensates with such nested morphologies. We specifically use the DNA nanostar system, and show that mixtures of nanostar particles with different sizes, and with strong homotypic attractions but weak heterotypic attractions, can lead to droplet-in-droplet structures. This strategy can be iterated to create a hierarchy of droplet nesting. We discuss the relation of mesoscopic morphology to the phase behavior of the nanostar particles.