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Small polar molecules like glycerol and urea can preserve the fluidity of lipid bilayers under dry conditions

Nowacka, Agnieszka LU ; Douezan, Stephane LU ; Wadsö, Ingemar LU ; Topgaard, Daniel LU and Sparr, Emma LU (2012) In Soft Matter 8(5). p.1482-1491
Abstract
Glycerol and urea are examples of small, water-soluble molecules with low vapor pressure that can protect lipid membranes upon dehydration. Both are a part of the Natural Moisturizing Factor in human skin, and are also present in other organisms, where they prevent drying due to osmotic stress. This study was conducted in order to understand the mechanism of such protection. We have selected two ternary systems: dimyristoylphosphatidylcholine (DMPC)-glycerol-water and DMPC-urea-water, as models to investigate the molecular mechanisms behind this protective effect with a focus on factors that control the solid to liquid phase transition in the phospholipid bilayers. By combining a number of experimental techniques, including solid-state... (More)
Glycerol and urea are examples of small, water-soluble molecules with low vapor pressure that can protect lipid membranes upon dehydration. Both are a part of the Natural Moisturizing Factor in human skin, and are also present in other organisms, where they prevent drying due to osmotic stress. This study was conducted in order to understand the mechanism of such protection. We have selected two ternary systems: dimyristoylphosphatidylcholine (DMPC)-glycerol-water and DMPC-urea-water, as models to investigate the molecular mechanisms behind this protective effect with a focus on factors that control the solid to liquid phase transition in the phospholipid bilayers. By combining a number of experimental techniques, including solid-state NMR, sorption microbalance and DSC, the structure and the phase transitions have been characterized at low water content and in excess solution. It was discovered that both glycerol and urea stabilize the liquid crystalline bilayers at low relative humidities (down to 75% RH at 27 degrees C), whereas for the pure DMPC-water system, a solid gel phase is induced at 93% RH. This demonstrates the protective effect of glycerol and urea against osmotic stress. It is further concluded that for lipid systems with limited access to solvent, the phase behavior is determined by solvent volume, irrespective of the composition. The observation that glycerol and urea have a similar effect on the lipid phase behavior under dry conditions, together with the lack of evidence of specific interactions between the lipids and glycerol or urea, implies a general mechanism, which might also be applicable to other, similar solutes. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Soft Matter
volume
8
issue
5
pages
1482 - 1491
publisher
Royal Society of Chemistry
external identifiers
  • wos:000298990600028
  • scopus:84855697852
ISSN
1744-6848
DOI
10.1039/c1sm06273e
language
English
LU publication?
yes
id
15013fbc-36e7-43a1-bc8c-49354bcd2f38 (old id 2362428)
date added to LUP
2012-02-23 14:47:47
date last changed
2017-03-05 04:01:09
@article{15013fbc-36e7-43a1-bc8c-49354bcd2f38,
  abstract     = {Glycerol and urea are examples of small, water-soluble molecules with low vapor pressure that can protect lipid membranes upon dehydration. Both are a part of the Natural Moisturizing Factor in human skin, and are also present in other organisms, where they prevent drying due to osmotic stress. This study was conducted in order to understand the mechanism of such protection. We have selected two ternary systems: dimyristoylphosphatidylcholine (DMPC)-glycerol-water and DMPC-urea-water, as models to investigate the molecular mechanisms behind this protective effect with a focus on factors that control the solid to liquid phase transition in the phospholipid bilayers. By combining a number of experimental techniques, including solid-state NMR, sorption microbalance and DSC, the structure and the phase transitions have been characterized at low water content and in excess solution. It was discovered that both glycerol and urea stabilize the liquid crystalline bilayers at low relative humidities (down to 75% RH at 27 degrees C), whereas for the pure DMPC-water system, a solid gel phase is induced at 93% RH. This demonstrates the protective effect of glycerol and urea against osmotic stress. It is further concluded that for lipid systems with limited access to solvent, the phase behavior is determined by solvent volume, irrespective of the composition. The observation that glycerol and urea have a similar effect on the lipid phase behavior under dry conditions, together with the lack of evidence of specific interactions between the lipids and glycerol or urea, implies a general mechanism, which might also be applicable to other, similar solutes.},
  author       = {Nowacka, Agnieszka and Douezan, Stephane and Wadsö, Ingemar and Topgaard, Daniel and Sparr, Emma},
  issn         = {1744-6848},
  language     = {eng},
  number       = {5},
  pages        = {1482--1491},
  publisher    = {Royal Society of Chemistry},
  series       = {Soft Matter},
  title        = {Small polar molecules like glycerol and urea can preserve the fluidity of lipid bilayers under dry conditions},
  url          = {http://dx.doi.org/10.1039/c1sm06273e},
  volume       = {8},
  year         = {2012},
}