Department of Chemistry, Michigan State University, East Lansing, Michigan 48824-1322, USA.
J Phys Chem B. 2010 Mar 25;114(11):3840-6. doi: 10.1021/jp910897t.
We have investigated the consequences of the addition of ethanol to aqueous solutions containing 100 nm diameter phosphocholine unilamellar vesicles. We have studied the effect of ethanol addition on both gel phase and fluid phase phospholipid bilayers of 1,2-dimyristoyl-sn-phosphatidylcholine (DMPC), using time-resolved fluorescence measurements of perylene incorporated into the vesicles. We observe an increase in the perylene rotational diffusion time constants for ethanol concentrations of ca. 0.6 M in both the gel phase (289 K) and the fluid phase (303 K), indicating a change in the bilayer interacyl chain spacing and/or organization. While the change in rotational diffusion behavior of perylene is seen for both phospholipid phases, the details of the change in chromophore dynamics are not the same for the two phases, likely due to the differing extents of disorder in the phospholipid acyl chain region at the two temperatures. These data provide insight into the effects of ethanol on the local environment of the probe in both gel phase and fluid phase lipid bilayers.
我们研究了在含有 100nm 直径磷酸胆碱单层囊泡的水溶液中加入乙醇的后果。我们使用掺入囊泡的苝的时间分辨荧光测量，研究了乙醇添加对 1,2-二肉豆蔻酰基-sn-磷脂酰胆碱 (DMPC) 的凝胶相和流体相磷脂双层的影响。我们观察到苝的旋转扩散时间常数在凝胶相（289K）和流体相（303K）中约 0.6M 的乙醇浓度下均增加，表明双层酰基链间距和/或组织发生了变化。虽然苝的旋转扩散行为在两种磷脂相中都发生了变化，但发色团动力学的变化细节在两相中并不相同，这可能是由于在这两个温度下磷脂酰链区域的无序程度不同所致。这些数据提供了对乙醇在凝胶相和流体相脂质双层中探针局部环境的影响的深入了解。
