Bilayer sheet protrusions and budding from bilayer membranes induced by hydrolysis and condensation reactions

Abstract

Shape transformations of flat bilayer membranes and vesicles induced by hydrolysis and condensation reactions of amphiphilic molecules are studied using coarse-grained molecular dynamics simulations. The hydrolysis and condensation reactions result in the formation and dissociation of amphiphilic molecules, respectively. Asymmetric reactions between the inner and outer leaflets of a vesicle can transport amphiphilic molecules between the leaflets. It is found that the resulting area difference between the two leaflets induces bilayer sheet protrusion (BP) and budding at low reduced volumes of the vesicles, whereas BP only occurs at high reduced volumes. The probabilities of these two types of transformations depend on the shear viscosity of the surrounding fluids compared to the membrane as well as the reaction rates. A higher surrounding fluid viscosity leads to more BP formation. The inhomogeneous spatial distribution of the hydrophobic reaction products forms the nuclei of BP formation, and faster diffusion of the products enhances BP formation. Our results suggest that adjustment of the viscosity is important to control membrane shape transformations in experiments.

Insight into the Polymerization-Induced Self-Assembly via a Realistic Computer Simulation Strategy

“…Wang and co-workers , had recently used dissipative particle dynamics (DPD) to simulate the PISA process and studied the influence of reaction rate, size of macro-CTA, and concentration on the kinetics of PISA. Besides, Shupanov et al had also used DPD combined with the Monte Carlo scheme to study the PISA as well as the relevant micellar polymerization process based on the BCP surfactants, in which the phase diagrams of the micelle states were constructed depending on the polymer concentration and the asymmetry of the composition for various reaction conditions. , Nakagawa and Noguchi , had also simulated the similar polymerization of amphiphilic molecules on the surface of the oil droplet, who had discovered that the polymerization could efficiently induce the transition of equilibrated self-assembly structures to other structures. Nevertheless, the only few simulation works are still based on generic model studies, and the authors mainly aimed to conveying proof-of-concept insights.…”

Membrane domain formation induced by binding/unbinding of curvature-inducing molecules onto both membrane surfaces

“…In nonequilib-rium steady states, the binding molecules can flow from the upper and lower solutions via flip-flop. Previously, such a flow has been reported for vesicles, in which inner and outer solutions are different, in experiments [57,58] and simulations [59].…”

Detachment of a fluid membrane from a substrate and vesiculation

“…The membrane detachment is a normal motion to the membrane while the vesiculation is also accompanied by the tangential motion. When the hydrodynamic interactions are taken into account, the tangential motion becomes relatively slower as the membrane viscosity increases compared to the solvent viscosity [49]. Thus, it is expected that the vesiculation occurs later for higher membrane viscosity.…”