Influence of the Preparation Route on the Supramolecular Organization of Lipids in a Vesicular System
Influence of the Preparation Route on the Supramolecular Organization of Lipids in a Vesicular System
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DOI：
10.1021/ja2086678
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发表时间：
2012-02-01
影响因子：
15
通讯作者：
Ventosa, Nora
中科院分区：
文献类型：
--
作者：
Elizondo, Elisa;Larsen, Jannik;Ventosa, Nora
采用共聚焦荧光显微法研究了制备途径对囊泡系统中脂质超分子组织的影响。本研究采用压缩流体法（DELOS-susp）或常规膜水合工艺制备了由胆固醇和CTAB （1/1 mol %）或胆固醇和DOPC （2/8 mol %）组成的囊泡，并加入了两种膜染料。随后将它们固定并使用共聚焦荧光显微镜单独成像。对每个跟踪的囊泡分配两个综合荧光强度i -染料1和i -染料2，并使用它们的比值i -染料1/ i -染料2来量化每个样品中单个囊泡之间的膜不均匀性程度。i -染料1/ i -染料2值在所有研究的囊泡系统中均有分布，表明样品内存在异质性。两种方法制备的Chol/DOPC囊泡的不均匀度（DI）相似。相比之下，在Chol/CTAB囊泡的情况下，水合法的DI是基于cf的方法的两倍多，Chol/CTAB囊泡在成膜过程中会受到脂质脱混的影响。这些发现揭示了CFs更均匀的囊泡形成路径，这保证了囊泡系统的良好均匀性，而不依赖于所使用的脂质混合物。
A confocal fluorescence microscopy-based assay was used for studying the influence of the preparation route on the supramolecular organization of lipids in a vesicular system. In this work, vesicles composed of cholesterol and CTAB (1/1 mol %) or cholesterol and DOPC (2/8 mol %) and incorporating two membrane dyes were prepared by either a compressed fluid (CF)-based method (DELOS-susp) or a conventional film hydration procedure. They were subsequently immobilized and imaged individually using a confocal fluorescence microscope. Two integrated fluorescence intensities, I-dye1 and I-dye2, were assigned to each tracked vesicle, and their ratio, I-dye1/I-dye2, was used for quantifying the degree of membrane inhomogeneity between individual vesicles within each sample. A distribution of I-dye1/I-dye2 values was obtained for all the studied vesicular systems, indicating intrasample heterogeneity. The degree of inhomogeneity (DI) was similar for Chol/DOPC vesicles prepared by both procedures. In contrast, DI was more than double for the hydration method compared to the CF-based method in the case of Chol/CTAB vesicles, which can suffer from lipid demixing during film formation. These findings reveal a more homogeneous vesicle formation path by CFs, which warranted good homogeneity of the vesicular system, independently of the lipid mixture used.