Thermodynamic and structural study of DMPC-alkanol systems
Mária Klacsová1, Attila Bóta, Peter Westh
1Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia. klacsova@fpharm.uniba.sk.
Physical Chemistry Chemical Physics : PCCP
|April 20, 2021
Summary
This study reveals how alkanols affect lipid bilayers, showing biphasic behavior and phase separation in dimyristoylphosphatidylcholine-alkanol systems, influenced by alkanol chain length.
Area of Science:
- Biophysics
- Materials Science
- Physical Chemistry
Background:
- Lipid bilayers are fundamental to cell membranes.
- Alkanols can alter lipid bilayer properties.
- Understanding these interactions is crucial for drug delivery and biomaterials.
Purpose of the Study:
- To investigate the thermodynamic and structural effects of alkanols on dimyristoylphosphatidylcholine (DMPC) lamellar systems.
- To determine how alkanol chain length influences bilayer behavior.
- To construct a phase diagram for a specific DMPC-alkanol system.
Main Methods:
- Differential Scanning Calorimetry (DSC) for thermodynamic analysis.
- Small-Angle X-ray Diffraction (SAXD) and Wide-Angle X-ray Diffraction (WAXD) for structural analysis.
- Systematic variation of alkanol chain length (C8-C18) and concentration.
Main Results:
- Observed biphasic behavior in DMPC-alkanol systems for alkanols with chain lengths up to C10, characterized by turning points (TP) and threshold concentrations (cT).
- Identified a shift in TP and cT to lower concentrations for alkanols with chain lengths greater than C10, leading to a monotonic increase in transition temperature (tm).
- Constructed a phase diagram for DMPC-C12OH, suggesting fluid-fluid immiscibility and domain formation above cT.
Conclusions:
- Alkanol concentration and chain length significantly influence DMPC bilayer thermodynamics and structure.
- The observed effects are attributed to a balance between van der Waals interactions and headgroup repulsion.
- Fluid-fluid immiscibility and domain formation are proposed mechanisms in DMPC-alkanol systems.
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