n-Butanol Partitioning and Phase Behavior in DPPC/DOPC Membranes

Membrane phase behavior and fluidization have been examined in heterogeneous membranes composed of dipalmitoylphosphatidylcholine (DPPC, a saturated lipid) and dioleoylphosphatidylcholine (DOPC, an unsaturated lipid) at n-butanol concentrations below and above the interdigitation threshold of DPPC....

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Bibliographic Details
Published in:The journal of physical chemistry. B 2012-05, Vol.116 (20), p.5919-5924
Main Authors: Kurniawan, Yogi, Venkataramanan, Keerthi P, Scholz, Carmen, Bothun, Geoffrey D
Format: Article
Language:English
Subjects:
1,2-Dipalmitoylphosphatidylcholine - chemistry
1-Butanol - chemistry
Calorimetry, Differential Scanning
Fluidizing
Fluorescence Polarization
Lipid Bilayers - chemistry
Lipids
Membranes
Partitioning
Phosphatidylcholines - chemistry
Physical chemistry
Thresholds
Unsaturated
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Summary:Membrane phase behavior and fluidization have been examined in heterogeneous membranes composed of dipalmitoylphosphatidylcholine (DPPC, a saturated lipid) and dioleoylphosphatidylcholine (DOPC, an unsaturated lipid) at n-butanol concentrations below and above the interdigitation threshold of DPPC. Our results show that the presence of DOPC did not influence the interdigitation concentration of n-butanol on DPPC (0.1–0.13 M) despite the fact that DOPC increased n-butanol partitioning into the membranes. When DPPC was the continuous phase, up to equimolar DPPC:DOPC, n-butanol partitioning into gel or interdigitated DPPC was only slightly affected by the presence of DOPC. In this case a “cooperative effect” of DOPC + n-butanol eliminated the DPPC pretransition phase and yielded an untilted gel-like phase. When DOPC was the continuous phase, more n-butanol was needed to cause DPPC interdigitation (0.2 M), which was attributed to n-butanol residing at the interface between DOPC and DPPC domains. To our knowledge, this is the first study to examine the effects of n-butanol partitioning on membranes composed of saturated and unsaturated lipids that exhibit coexisting phase states.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp301340k