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Transport Processes in Responding Lipid Membranes: A Possible Mechanism for the pH Gradient in the Stratum Corneum

Åberg, Christoffer LU ; Wennerström, Håkan LU and Sparr, Emma LU (2008) In Langmuir 24(15). p.8061-8070
Abstract
The “acidic mantle” of the skin surface has been related to several essential functions of the skin, although the origin of the acidity is still obscure. In this paper, we investigate how different transport processes can influence the local proton concentration inside a membrane consisting of oriented lipid bilayers. This system is chosen as a simple model of the extracellular lipids in the upper layer of the skin, the stratum corneum. We present a theoretical model for diffusional transport over the membrane in the presence of an osmotic gradient and a gradient in CO2, taking into account the influence of these gradients on the lipid structure and the local electrostatics. We are also discussing the complications in applying the concept... (More)
The “acidic mantle” of the skin surface has been related to several essential functions of the skin, although the origin of the acidity is still obscure. In this paper, we investigate how different transport processes can influence the local proton concentration inside a membrane consisting of oriented lipid bilayers. This system is chosen as a simple model of the extracellular lipids in the upper layer of the skin, the stratum corneum. We present a theoretical model for diffusional transport over the membrane in the presence of an osmotic gradient and a gradient in CO2, taking into account the influence of these gradients on the lipid structure and the local electrostatics. We are also discussing the complications in applying the concept of pH to the stratum corneum. From this, we make the following conclusions: (i) The definition of pH in the stratum corneum is ambiguous, and thus, all statements regarding pH should always be related to a clear definition. (ii) A natural definition of pH in the stratum corneum can be proposed which takes into account local heterogeneity, local charges, and the fact that the stratum corneum is not in thermodynamical equilibrium. (iii) Diffusive transport across an oriented bilayer stack in the presence of an osmotic gradient and/or a gradient in CO2 can give rise to a substantial gradient in pH. (iv) The results from the simplified model can be correlated to experimental observations of pH in the stratum corneum. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
24
issue
15
pages
8061 - 8070
publisher
The American Chemical Society
external identifiers
  • wos:000258034500061
  • scopus:49649128460
ISSN
0743-7463
DOI
10.1021/la800543r
language
English
LU publication?
yes
id
1693364d-8879-4695-99f3-9ac72e609f4d (old id 1226041)
date added to LUP
2008-09-03 11:57:34
date last changed
2017-01-01 05:16:46
@article{1693364d-8879-4695-99f3-9ac72e609f4d,
  abstract     = {The “acidic mantle” of the skin surface has been related to several essential functions of the skin, although the origin of the acidity is still obscure. In this paper, we investigate how different transport processes can influence the local proton concentration inside a membrane consisting of oriented lipid bilayers. This system is chosen as a simple model of the extracellular lipids in the upper layer of the skin, the stratum corneum. We present a theoretical model for diffusional transport over the membrane in the presence of an osmotic gradient and a gradient in CO2, taking into account the influence of these gradients on the lipid structure and the local electrostatics. We are also discussing the complications in applying the concept of pH to the stratum corneum. From this, we make the following conclusions: (i) The definition of pH in the stratum corneum is ambiguous, and thus, all statements regarding pH should always be related to a clear definition. (ii) A natural definition of pH in the stratum corneum can be proposed which takes into account local heterogeneity, local charges, and the fact that the stratum corneum is not in thermodynamical equilibrium. (iii) Diffusive transport across an oriented bilayer stack in the presence of an osmotic gradient and/or a gradient in CO2 can give rise to a substantial gradient in pH. (iv) The results from the simplified model can be correlated to experimental observations of pH in the stratum corneum.},
  author       = {Åberg, Christoffer and Wennerström, Håkan and Sparr, Emma},
  issn         = {0743-7463},
  language     = {eng},
  number       = {15},
  pages        = {8061--8070},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Transport Processes in Responding Lipid Membranes: A Possible Mechanism for the pH Gradient in the Stratum Corneum},
  url          = {http://dx.doi.org/10.1021/la800543r},
  volume       = {24},
  year         = {2008},
}