Imaginary Biology: Exploring Long-range Structures in DNA-Based Condensates

Biological cells have evolved to create elaborate internal partitions, which allow them to control biochemical and genetic processes in space and time. Increasing evidence indicates that some of these partitions are created by the phase separation of large biological molecules, in which complex mixtures of RNA and protein associate to form dense globules (‘condensates’), frequently with liquid-like properties. We study the underlying physical aspects of such biomolecular phase separation processes, particularly by performing experiments with a highly-tunable model system of ~10 nm DNA particles. We have developed the ability to use nanoscopic changes to the particles, and/or biologically-inspired non-equilibrium processing schemes, to drive the formation of structures and patterns on micron to millimeter scales. These scales transcend what is strictly relevant within the cell; instead they represent what might be called an ‘imaginary biology’ of locally disordered biomolecular phases that form emergent long-range structures.