Cover image by James C. S. Ho and Atul N. Parikh. Giant lipid vesicles, topologically closed flexible compartments, subject to solute concentration gradients dissipate the available chemical energy through the osmotic movement of water, producing shape transformations driven by surface-area–volume changes.
Upon immersion in a hypertonic bath, the increased surface-area–volume ratio promotes large-scale morphological remodeling, reducing symmetry and stabilizing irregular shapes determined by the equilibrium minimal bending energy configurations.
By contrast, when subjected to hypotonic bath, walls of giant vesicles lose thermal undulation, accumulate mechanical tension, and, beyond a threshold swelling, exhibit characteristic oscillatory swell–burst cycles, the latter characterized by damped, periodic oscillations in vesicle size, membrane tension, and domain patterns in phase-separating membrane shells.
For more information, see “Mixing Water, Transducing Energy, and Shaping Membranes: Autonomously Self-Regulating Giant Vesicles” by James C. S. Ho, Padmini Rangamani, Bo Liedberg, and Atul N. Parikh (DOI: 10.1021/acs.langmuir.5b04470).