Encapsulation of aqueous two-phase systems and gels within giant lipid vesicles

The aqueous interior of giant unilamellar vesicles (GUVs) can be subdivided into two or more distinct regions by encapsulating polymeric solutes to render the interior solution capable of either liquid-liquid phase separation or gelation. GUVs that incorporate coexisting microcompartments of distinct composition and properties are of interest as simple models for compartmentalization in biological cells. This chapter provides insight and advice for the encapsulation of aqueous two-phase systems (ATPS) and gels within GUVs. The phase behavior of polymer and gel systems is discussed, as well as the motivation for containing these systems within GUVs. Approaches to encapsulation are presented along with method-specific guidance. In order to highlight the range of information that can be gathered from studying these compartmentalized GUV systems, common types of experiments are reviewed.