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Phase behavior of fully hydrated DMPC-amphiphilic cyclodextrin systems
S Lesieur1, D Charon, P Lesieur
1Laboratoire de Physico-Chimie-Pharmacotechnie-Biopharmacie, UMR CNRS 8612, Université Paris-Sud, Faculté de Pharmacie, 5 rue J. B. Clément, F-92296 cedex, Châtenay-Malabry, France. sylviane.lesieur@cep.u-psud.fr
Chemistry and Physics of Lipids
|August 10, 2000
Summary
This study investigates the mixing of amphiphilic beta-cyclodextrin (beta-CDC(6)) with dimyristoylphosphatidylcholine (DMPC). Results show partial miscibility, with phase separation occurring above specific molar ratios, impacting mixed monolayer and lamellar structures.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Physical Chemistry
Background:
- Understanding the physico-chemical properties of amphiphilic cyclodextrins is crucial for their applications.
- Heptakis (2,3-di-O-hexanoyl)-beta-cyclodextrin (beta-CDC(6)) is an amphiphilic derivative of beta-cyclodextrin.
- Phospholipids like dimyristoylphosphatidylcholine (DMPC) are key components of biological membranes.
Purpose of the Study:
- To characterize the newly synthesized beta-CDC(6).
- To investigate the miscibility and formation of mixed structures between beta-CDC(6) and DMPC.
- To explore the structure-property relationships of these amphiphilic mixtures.
Main Methods:
- Synthesis and chemical characterization of beta-CDC(6).
- Surface pressure-area isotherm analysis of mixed monolayers at the air-water interface.
- Differential scanning calorimetry (DSC) and small/wide-angle X-ray diffraction of hydrated mixtures.
Main Results:
- Beta-CDC(6) and DMPC exhibit partial miscibility, with phase separation observed above 7-15 mol% beta-CDC(6).
- Mixed monolayers display non-ideal behavior, indicated by non-additive molecular areas.
- Hydrated mixtures form mixed lamellar phases, except at ~5 mol% beta-CDC(6) where a highly ordered structure emerges; higher beta-CDC(6) leads to coexisting hexagonal phases.
Conclusions:
- The miscibility and phase behavior of beta-CDC(6)/DMPC mixtures are dependent on composition and dimensional scale.
- These findings provide insights into the self-assembly of amphiphilic cyclodextrin-lipid systems.
- The study highlights the potential for tailored supramolecular structures through controlled mixing of amphiphiles.