Vesicle Concentration as a Factor in NaCl-Induced Structural Transitions of Lipid Vesicles

The physics of cell membranes play an important role in biological systems and affect fields from drug delivery to cosmetics. The simplest model of the cell membrane is the lipid vesicle. Various medical conditions related to high sodium states in the human body highlight the importance of understanding the interaction of lipid membranes with NaCl. Concentration-dependent effects, including osmotic pressure and electrostatic effects induced by the addition of salt to a system of small unilamellar lipid vesicles, can lead to rupture and thereby the development of various multilamellar structures. Lipid vesicle concentration affects the onset NaCl concentration for these changes. We begin with a well-defined system, a small, unilamellar lipid vesicle, then examine the effect of NaCl concentration on the structure of Lipid vesicles at different vesicle concentrations, focusing particularly on the number of lamellae and effects on size and size distribution, to examine the role of osmotic pressure resulting from the lipid vesicles themselves.