Related Experiment Videos
Structure and interactions of fully hydrated dioleoylphosphatidylcholine bilayers
S Tristram-Nagle1, H I Petrache, J F Nagle
1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 USA. stn+@andrew.cmu.edu
Biophysical Journal
|July 24, 1998
Summary
This study quantifies the area compressibility of hydrated dioleoylphosphatidylcholine (DOPC) lipid bilayers. Researchers found fluctuation pressure decays exponentially with water spacing, offering insights into lipid bilayer interactions near full hydration.
Area of Science:
- Biophysics
- Materials Science
- Physical Chemistry
Background:
- Phospholipids like dioleoylphosphatidylcholine (DOPC) are fundamental to biological membranes.
- Understanding lipid bilayer properties near full hydration is crucial for membrane biophysics.
Purpose of the Study:
- To determine the area compressibility and structural parameters of hydrated DOPC bilayers.
- To investigate the role of liquid crystal fluctuations and fluctuation pressure in lipid bilayers.
Main Methods:
- Utilized volumetric and high-resolution synchrotron X-ray diffraction data.
- Compared DOPC with dipalmitoylphosphatidylcholine (DPPC) under varying osmotic pressures (0-56 atm).
- Applied corrections for liquid crystal fluctuations to obtain electron density profiles.
Main Results:
- Determined the fully hydrated area per lipid (A0) for DOPC as 72.2 ± 1.1 Ų at 30°C.
- Estimated the area compressibility (KA) to be 188 dyn/cm.
- Quantified fluctuation pressure decay with water spacing, finding a decay length ratio deviating from theoretical predictions.
Conclusions:
- The study provides key structural and mechanical properties of hydrated DOPC bilayers.
- Experimental data on fluctuation pressure align with soft confinement theories but show discrepancies in decay length ratios compared to analytical predictions.
- Hamaker parameter and bending modulus estimates are shown to be coupled.