A temperature gradient method for lipid phase diagram construction using time-resolved x-ray diffraction.
Citation:
Caffrey M, Hing FS, A temperature gradient method for lipid phase diagram construction using time-resolved x-ray diffraction., Biophysical journal, 51, 1, 1987, 37-46Download Item:
Abstract:
A method that enables temperature-composition phase diagram construction at unprecedented rates is
described and evaluated. The method involves establishing a known temperature gradient along the length of a metal
rod. Samples of different compositions contained in long, thin-walled capillaries are positioned lengthwise on the rod
and "equilibrated" such that the temperature gradient is communicated into the sample. The sample is then moved
through a focused, monochromatic synchroton-derived x-ray beam and the image-intensified diffraction pattern from
the sample is recorded on videotape continuously in live-time as a function of position and, thus, temperature. The
temperature at which the diffraction pattern changes corresponds to a phase boundary, and the phase(s) existing
(coexisting) on either side of the boundary can be identified on the basis of the diffraction pattern. Repeating the
measurement on samples covering the entire composition range completes the phase diagram. These additional samples
can be conveniently placed at different locations around the perimeter of the cylindrical rod and rotated into position for
diffraction measurement. Temperature-composition phase diagrams for the fully hydrated binary mixtures, dimyristoylphosphatidylcholine
(DMPC)/dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylethanolamine
(DPPE)/DPPC, have been constructed using the new temperature gradient method. They agree well with and extend
the results obtained by other techniques. In the DPPE/DPPC system structural parameters as a function of
temperature in the various phases including the subgel phase are reported. The potential limitations of this steady-state
method are discussed.
Author's Homepage:
http://people.tcd.ie/mcaffreDescription:
PUBLISHED
Author: CAFFREY, MARTIN
Type of material:
Journal ArticleCollections
Series/Report no:
Biophysical journal51
1
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Full text availableDOI:
http://dx.doi.org/10.1016/S0006-3495(87)83309-XISSN:
0006-3495Metadata
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