(5g) Enzyme-Powered Surface-Adherent Protocells from Double Emulsion-Templated Polymersomes

Cellular biomimicry using artificial cells, or protocells, can not only enhance our understanding of complex physical processes essential for maintaining life, but also enable the development of autonomously functioning particles whose capabilities extend what is currently achievable in biology. While lipids, which are the principal component of most biological membranes, traditionally serve as a frame for artificial cells, vesicles assembled from synthetic block copolymers, or polymersomes, can be imparted with unique properties that widen the palette of possible responses programmed by nature. Our lab previously demonstrated that catalase-containing surface-adherent polymersomes made from poly(ethylene oxide) – b – poly(1,2 butadiene) display random autonomous motion – akin to eukaryotic cell motion – in the presence of hydrogen peroxide. However, these experiments used heterogenous populations of polymersomes made from thin-film rehydration. Thus, in an effort to create a more elegant platform for enzyme-driven motion, here we use a surfactant-assisted high-yielding microfluidic approach to form monodisperse, unilamellar polymersomes. The key to this approach is precise control over the interfacial energies of the evolving W/O/W emulsion system via addition of Pluronic F-68 to the outer aqueous phase, which ensures complete separation of the inner aqueous droplet from the oil shell. Under sufficiently high surfactant concentrations, spontaneous dewetting is observed in as fast as 10 minutes following double emulsion fabrication. The extent and time of dewetting is controlled by the amount of F-68 added to the outer aqueous phase. We explore the use of these capsules by incorporating coacervating proteins within the lumen to self-assemble into membraneless organelles, as one step towards the larger goal of recreating a natural cell using designer bio-inspired materials. Moreover, we propose to attach high force-generating enzymes, including catalase and urease, to the shell of these capsules and examine their motion both in solution and on adherent surfaces in response to enzymatic turnover.