Das, C, Olmsted, PD and Noro, MG (2009) Water permeation through stratum corneum lipid bilayers from atomistic simulations. Soft Matter, 5 (22). 4549 - 4555. ISSN 1744-683X
Abstract
Stratum corneum, the outermost layer of skin, consists of keratin filled rigid non-viable corneocyte cells surrounded by multilayers of lipids. The lipid layer is responsible for the barrier properties of the skin. We calculate the excess chemical potential and diffusivity of water as a function of depth in lipid bilayers with compositions representative of the stratum corneum using atomistic molecular dynamics simulations. The maximum in the excess free energy of water inside the lipid bilayers is found to be twice that of water in phospholipid bilayers at the same temperature. Permeability, which decreases exponentially with the free energy barrier, is reduced by several orders of magnitude as compared with phospholipid bilayers. The average time it takes for a water molecule to cross the bilayer is calculated by solving the Smoluchowski equation in the presence of the free energy barrier. For a bilayer composed of a 2:2:1 molar ratio of ceramide NS 24:0, cholesterol and free fatty acid 24:0 at 300 K, we estimate the permeability P = 3.7 × 10-9 cm/s and the average crossing time τav = 0.69 ms. The permeability is about 30 times smaller than existing experimental results on mammalian skin sections.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2009, Royal Society of Chemistry. This is an author produced version of a paper published in Soft Matter. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Molecular-dynamics simulations; barrier function; constant-pressure; human skin; permeability; hydration; models; cholesterol; transitions; morphology |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Oct 2014 11:20 |
Last Modified: | 25 Apr 2015 11:48 |
Published Version: | http://dx.doi.org/10.1039/b911257j |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/b911257j |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80483 |