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Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy
Published on: October 24, 2017
Fluorescent probes alter miscibility phase boundaries in ternary vesicles.
Sarah L Veatch1, Sherry S W Leung, Robert E W Hancock
1Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
The Journal of Physical Chemistry. B
|January 19, 2007
Summary
Fluorescent probes significantly alter lipid membrane miscibility transitions. Even trace amounts of DiIC12 dramatically increase transition temperatures and affect lipid ordering in phospholipid bilayers.
Area of Science:
- Membrane biophysics
- Lipid self-assembly
- Materials science
Background:
- Phosphatidylcholine (PC) and cholesterol form complex lipid bilayers.
- Miscibility transitions in lipid membranes are crucial for cellular function.
- Fluorescent probes are widely used to study membrane properties.
Purpose of the Study:
- To investigate the impact of fluorescent probes (DiIC12 and DiOC18) on lipid miscibility transitions.
- To quantify the effect of probe concentration on membrane phase behavior.
- To understand how probes influence lipid ordering and phase boundaries.
Main Methods:
- Deuterium nuclear magnetic resonance (2H NMR) spectroscopy.
- Studying multilamellar vesicles composed of specific phosphatidylcholine lipids (DOPC, DPPCd62) and cholesterol.
- Varying the concentration of fluorescent probes (DiIC12, DiOC18).
Main Results:
- Both DiIC12 and DiOC18 increased the miscibility transition temperature in 1:1 DOPC/DPPCd62 + 30% cholesterol mixtures.
- DiIC12 significantly increased the fraction of DPPCd62 in the liquid disordered phase and reduced its ordering.
- Even 0.05 mol % DiIC12 drastically elevated the transition temperature, indicating sensitivity to trace components.
Conclusions:
- Fluorescent probes can significantly expand the miscibility phase boundary of lipid membranes.
- Trace amounts of probes can dramatically alter the phase behavior and ordering of lipid bilayers.
- Findings highlight the importance of considering probe artifacts in membrane studies.
