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Nonequilibrium behavior in supported lipid membranes containing cholesterol
Benjamin L Stottrup1, Sarah L Veatch, Sarah L Keller
1Departments of Chemistry and Physics, University of Washington, Seattle, Washington, USA.
Biophysical Journal
|April 28, 2004
Summary
Supported lipid membranes and monolayers show static domains, unlike dynamic domains in vesicles. This difference impacts how lipid collective behavior is studied in artificial cell membrane models.
Area of Science:
- Biophysics
- Materials Science
- Surface Chemistry
Background:
- Lipid domains are crucial for cell membrane function.
- Vesicles and supported membranes are models for studying lipid organization.
- Previous studies show coexisting liquid phases in lipid mixtures.
Purpose of the Study:
- To compare lateral organization of lipid domains in vesicles versus supported membranes and monolayers.
- To investigate the transferability and stability of lipid domains onto solid supports.
Main Methods:
- Utilized lipid mixtures (DOPC/DPPC/Chol and DOPC/BSM/Chol) known to form liquid phases.
- Employed Langmuir-Schäfer deposition to transfer lipid monolayers onto silanized glass and supported monolayers.
- Analyzed domain presence and characteristics before and after transfer, and on different supports.
Main Results:
- Micron-scale lipid domains transferred to supports were static, unlike dynamic domains in vesicles.
- Transferred domains did not align across leaflets or reappear after temperature cycling.
- Supported membranes reproduced some equilibrium properties but poorly mimicked collective lipid domain behavior.
Conclusions:
- Supported membranes and monolayers are limited models for replicating the dynamic collective behavior of lipid domains found in vesicles.
- Static domains on supports differ significantly from fluid domains in biological membranes.
- Further development of model systems is needed to accurately study lipid domain dynamics.