title: Dynamic domains in polymersomes: mixtures of polyanionic and neutral diblocks respond more rapidly to changes in calcium than to pH.
abstract: Chemical triggering of membrane domain dynamics is of broad relevance to cell signaling through lipid bilayers and might also be exploited in application of phase-separated vesicles. Here we describe the morphodynamics and remixing kinetics of spotted polymersomes made with mixtures of polyanionic and neutral amphiphiles plus calcium. Addition of the calcium chelator EDTA to vesicle dispersions produced a decrease in domain size within minutes, whereas increasing the pH with NaOH led to the viscous fingering of domains and decreased domain size over hours. Although the latter suggests that the charge of the polyanion contributes to domain formation, the remixing of more negative chains at high pH is surprising. Domain roughening at high pH is also accelerated by EDTA, which highlights the dominance of cross-bridging. Importantly, even though vesicles were perturbed only externally, the inner and outer leaflets remain coupled throughout, consistent with molecular dynamics simulations and suggestive of an order-disorder transition that underlies the remixing kinetics.
authors: Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
authors: Kyle
authors: K
authors: Spinler
authors: Aiwei
authors: A
authors: Tian
authors: David A
authors: DA
authors: Christian
authors: Diego A
authors: DA
authors: Pantano
authors: Tobias
authors: T
authors: Baumgart
authors: Dennis E
authors: DE
authors: Discher
mesh_terms: D000838:Anions; D002118:Calcium / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D011108:Polymers / Q000737:chemistry*
chemical_list: D000838:Anions; D011108:Polymers; D004492:Edetic Acid; D002118:Calcium