Effect of ethanol on dimyristoylphosphatidylcholine large unilamellar vesicles investigated by quasi-elastic light scattering and vibrational spectroscopy.
The gel-like liquid phase transition of dimyristoylphosphatidylcholine (DMPC) large unilamellar vesicles prepared by reverse phase evaporation has been investigated in buffers containing ethanol by quasi-elastic light scattering (QLS) and vibrational (infrared and Raman) spectroscopy. With the QLS technique, the relative change in the vesicles area (which is related to the molecular cross-sectional area of lipid molecules) was followed versus both temperature and ethanol concentration. When the latter was low, the depression of the transition point was a linear function of the alcohol concentration, c, but the vesicles area was practically unmodified. At alcohol concentration 10% v/v, an abrupt change of the vesicles area was observed and for c greater than 10% the depression of the transition point was a non-linear function of c. The infrared and Raman spectra showed a perturbation of the hydrophobic regions, including the terminal methyl groups of the acyl tails.
Hantz
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Laboratoire de Spectroscopie Biomoléculaire, Université Paris XIII, Bobigny, France.
Cao
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Taillandier
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D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004134:Dimyristoylphosphatidylcholine; D000431:Ethanol / Q000494:pharmacology*; D008081:Liposomes / Q000032:analysis*; D008560:Membrane Fluidity / Q000187:drug effects; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature; D014732:Vibration
D008081:Liposomes; D000431:Ethanol; D004134:Dimyristoylphosphatidylcholine