Practical considerations for generation of multi-compartment complex coacervates.

We discuss preparation of experimental models for multi-compartment membraneless organelles in which distinct compositions are maintained indefinitely for macromolecule-rich phases in contact with each other. These model systems are based on the physical chemistry phenomenon of complex coacervation. In complex coacervation, liquid-liquid phase separation occurs due to ion pairing interactions between oppositely charged polyelectrolytes. This mechanism can drive the associative phase separation of proteins and nucleic acids, the major macromolecular components of membraneless organelles. Here we provide examples, advice and practical considerations for the design, generation, and analysis of multi-compartment complex coacervates. These structures are of interest to compartmentalize the interior of artificial cells and as models for the intracellular membraneless organelles of biological cells.