(305c) Awe-Somes: All Water Emulsion Bodies

We are developing encapsulation methods via interfacial complexation of polyelectrolytes and other charged species in all aqueous two phase systems to make multi-functional All Water Emulsion bodies- AWE-somes. Such capsules can be particularly interesting for sequestration of delicate components, including proteins and microbes, which should not be placed in contact with oils or hydrophobic media. These platforms have several exciting applications, and open interesting questions for fundamental study.

Here we discuss the example of the PEG-Dextran-water system, which separates into PEG-rich and dextran-rich phases. The interfacial tension between the phases is quite low. Furthermore, many molecules, including polyelectrolytes, partition freely between the two phases. These factors make interfacial structure formation especially challenging. We develop strategies to build membranes from complementary polyelectrolytes in each phase by balancing their rates of transport to the interface. To impart additional functionality, we develop methods to include charged nanoparticles (NPs) in such membranes. Here, NPs can be selected that preferentially partition into one of the phases, facilitating interfacial transport, and creating an osmotic stress imbalance between the two phases that allows us to form encapsulated multiple emulsions. These AWE-somes, with internal structures reminiscent of membraneless organelles, provide a rich platform for separation, partitioning, reaction, and transport, suggesting AWE-somes might be developed into protocell systems.