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Title: Insights into the structure and nanomechanics of a quatsome membrane by force spectroscopy measurements and molecular simulation
Author: Gumí Audenis, Berta
Illa Tuset, Silvia
Grimaldi, Natascia
Pasquina Lemonche, Laia
Ferrer Tasies, Lídia
Sanz Carrasco, Fausto
Veciana, Jaume
Ratera, Imma
Faraudo, Jordi
Ventosa, Nora
Giannotti, Marina Ines
Keywords: Dinàmica molecular
Membranes (Biologia)
Microscòpia de força atòmica
Molecular dynamics
Membranes (Biology)
Atomic force microscopy
Issue Date: 12-Nov-2018
Publisher: Royal Society of Chemistry
Abstract: Quatsomes (QS) are unilamellar nanovesicles constituted by quaternary ammonium surfactants and sterols in defined molar ratios. Unlike conventional liposomes, QS are stable upon long storage such as for several years, they show outstanding vesicle-to-vesicle homogeneity regarding size and lamellarity, and they have the structural and physicochemical requirements to be a potential platform for site-specific delivery of hydrophilic and lipophilic molecules. Knowing in detail the structure and mechanical properties of the QS membrane is of great importance for the design of deformable and flexible nanovesicle alternatives, highly pursued in nanomedicine applications such as the transdermal administration route. In this work, we report the first study on the detailed structure of the cholesterol : CTAB QS membrane at the nanoscale, using atomic force microscopy (AFM) and spectroscopy (AFM-FS) in a controlled liquid environment (ionic medium and temperature) to assess the topography of supported QS membranes (SQMs) and to evaluate the local membrane mechanics. We further perform molecular dynamics (MD) simulations to provide an atomistic interpretation of the obtained results. Our results are direct evidence of the bilayer nature of the QS membrane, with characteristics of a fluid-like membrane, compact and homogeneous in composition, and with structural and mechanical properties that depend on the surrounding environment. We show how ions alter the lateral packing, modifying the membrane mechanics. We observe that according to the ionic environment and temperature, different domains may coexist in the QS membranes, ascribed to variations in molecular tilt angles. Our results indicate that QS membrane properties may be easily tuned by altering the lateral interactions with either different environmental ions or counterions.
Note: Versió postprint del document publicat a:
It is part of: Nanoscale, 2018, vol. 10, num. 48, p. 23001-23011
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ISSN: 2040-3364
Appears in Collections:Articles publicats en revistes (Ciència dels Materials i Química Física)
Articles publicats en revistes (Institut de Bioenginyeria de Catalunya (IBEC))

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