Unexpected stability of phospholipid langmuir monolayers deposited on Triton X-100 aqueous solutions.
We studied at the molecular level the interaction between neutral detergent Triton X-100 aqueous solution and a phospholipid Langmuir monolayer deposited on top using surface pressure measurement and grazing incidence X-ray diffraction (GIXD). Macroscopically, the detergent-phospholipid system follows the Gibbs law. However, GIXD shows that the detergent and the phospholipid segregate at the interface. The molecular organization of pure phospholipid domains is imposed by the detergent through surface pressure. Compression and expansion of the surface monolayer system in its final state reveal the stability of the phospholipids domains against dissolution by the detergent in the subphase, even above the detergent cmc. This resistance to dissolution is suppressed by an expansion of the monolayer.
Fontaine
Philippe
P
Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin, BP48, 91192 Gif sur Yvette Cedex, France. philippe.fontaine@synchrotron-soleil.fr
Fauré
Marie Claude
MC
Muller
François
F
Poujade
Mathieu
M
Micha
Jean-Sébastien
JS
Rieutord
François
F
Goldmann
Michel
M
D017830:Octoxynol / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D010743:Phospholipids; D012996:Solutions; D013501:Surface-Active Agents; D014867:Water; D017830:Octoxynol