Neutron Scattering Reveals Water Confined in a Watertight Bilayer Vesicle

Abstract

Water molecules confined in a nanocavity possess distinctly different characteristics from those in bulk, yet the preparation of such nanocavities is still a major experimental challenge. We report here a self-assembled vesicle of an anionic perfluoroalkylated [60]fullerene, unique for its outstanding stability and water tightness, containing water not bound to the membranes. Small-angle neutron scattering revealed that a vesicle of 14 nm outer radius contains a 2 nm thick fullerene bilayer, inside of which is a 3 nm thick membrane-bound water and unbound water in the 4 nm innermost cavity. The vesicle shows astonishingly low water permeability that is 6 to 9 orders of magnitude smaller than that of a lipid vesicle. As a result, a single vesicle isolated on a substrate can retain the interior water in air or even under high vacuum, indicating that the vesicle cavity provides a new tool for physicochemical studies of confined water as well as ions and molecules dissolved in it.

Generalization of Langevin Dynamics from Spatio-Temporal Dressed Dynamics Perspective

“…In diverse soft matter systems, the physio-chemical nature of the solvation shell could be very different; for instance, in the glass transition, the shells are built by the strong hydrogen bond network, and in the biological systems, the shells rise from the active interactions between biomolecules. ,− To quantitatively resolve the complexity of the real dynamics, this temporal dressed diffusion equation can be extended with more medium components each with different lifetime to describe the particle–medium interactions.…”

“…In recent years, microscopic measurements with unprecedented resolution unraveled new clues on the role of medium’s inhomogeneity in the non-Brownian dynamics. − In particular, ultrastrong damping of particle motion by several orders of magnitude indicated the strong interactions inside the system as measured by the liquid cell electron microscopy with excellent spatial resolution . To address these intriguing experimental observations, one temporal dressed diffusion model was recently developed by including particle–medium interactions in the system, which provided the needed framework for studying the multiscale dynamics beyond the scope of Langevin equation .…”

Unraveling Dynamic Transitions in Time-Resolved Biomolecular Motions by A Dressed Diffusion Model

“…2 , where r here is the spatial displacement relative to the ground state. 1 The long-term limit of this special kinetics is the confinement limit; that is, 35 This idea is equivalent with a specific case of our model: when λ = 0, a = −k/m, and b = 1, the negative part of the VAC cancels out the positive part. Besides, the classical Brownian diffusion can be retrieved by setting the couplings equal zero in eq 1 (Figure 1b).…”

“…The diffusion within confinement has been described by Kramers with a static parabolic potential well , where r here is the spatial displacement relative to the ground state . The long-term limit of this special kinetics is the confinement limit; that is, ⟨ r 2 ⟩( t → ∞) = constant . This idea is equivalent with a specific case of our model: when λ = 0, a = − k / m , and b = 1, the negative part of the VAC cancels out the positive part.…”

Dendronized oligoethylene glycols with phosphonate tweezers for cell-repellent coating of oxide surfaces: coarse-scale and nanoscopic interfacial forces

“…Water molecules conned near surfaces have been drawing increasing attention because of their physical characteristics distinct from those in the bulk. [35][36][37] Using frequency modulation AFM, Jarvis and co-workers identied layered water near the surface of crystalline-like, carboxyl-terminated thiol monolayers as oscillatory force signals separated at a distance of z0.25 nm. 38 Inada et al took a similar approach on highly ordered monolayers of oligoethylene glycol chains connected to alkanethiols.…”