General hydrophobic interaction potential for surfactant/lipid bilayers from direct force measurements between light-modulated bilayers
- 6 September 2011
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 108 (38), 15699-15704
- https://doi.org/10.1073/pnas.1112411108
Abstract
We establish and quantify correlations among the molecular structures, interaction forces, and physical processes associated with light-responsive self-assembled surfactant monolayers or bilayers at interfaces. Using the surface forces apparatus (SFA), the interaction forces between adsorbed monolayers and bilayers of an azobenzene-functionalized surfactant can be drastically and controllably altered by light-induced conversion of trans and cis molecular conformations. These reversible conformation changes affect significantly the shape of the molecules, especially in the hydrophobic region, which induces dramatic transformations of molecular packing in self-assembled structures, causing corresponding modulation of electrostatic double layer, steric hydration, and hydrophobic interactions. For bilayers, the isomerization from trans to cis exposes more hydrophobic groups, making the cis bilayers more hydrophobic, which lowers the activation energy barrier for (hemi)fusion. A quantitative and general model is derived for the interaction potential of charged bilayers that includes the electrostatic double-layer force of the Derjaguin-Landau-Verwey-Overbeek theory, attractive hydrophobic interactions, and repulsive steric-hydration forces. The model quantitatively accounts for the elastic strains, deformations, long-range forces, energy maxima, adhesion minima, as well as the instability (when it exists) as two bilayers breakthrough and (hemi)fuse. These results have several important implications, including quantitative and qualitative understanding of the hydrophobic interaction, which is furthermore shown to be a nonadditive interaction.Keywords
This publication has 29 references indexed in Scilit:
- Photocontrolled Self-Assembly and Disassembly of Block Ionomer Complex Vesicles: A Facile Approach toward Supramolecular Polymer NanocontainersLangmuir, 2009
- Spatial and temporal control of surfactant systemsJournal of Colloid and Interface Science, 2009
- Photoreversible Conformational Changes in Membrane Proteins Using Light-Responsive SurfactantsThe Journal of Physical Chemistry B, 2009
- Dynamic Surface Tension Behavior in a Photoresponsive Surfactant SystemLangmuir, 2007
- Photoreversible DNA Condensation Using Light-Responsive SurfactantsJournal of the American Chemical Society, 2006
- Photocontrol of Protein Folding: The Interaction of Photosensitive Surfactants with Bovine Serum AlbuminBiochemistry, 2004
- Comparison of the Surface Activity and Bulk Aggregation of Ferrocenyl Surfactants with Cationic and Anionic HeadgroupsLangmuir, 2001
- Photochemical Switching of Vesicle Formation Using an Azobenzene-Modified SurfactantThe Journal of Physical Chemistry B, 1999
- Molecular mechanisms and kinetics during the self-assembly of surfactant layersJournal of Colloid and Interface Science, 1992
- Adsorption of sodium dodecyl sulfate at various hydrocarbon-water interfacesThe Journal of Physical Chemistry, 1967