Influence of the Preparation Route on the Supramolecular Organization of Lipids in a Vesicular System
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- 作者：Elisa Elizondo ; Jannik Larsen ; Nikos S. Hatzakis ; Ingrid Cabrera ; Thomas Bj酶rnholm ; Jaume Veciana ; Dimitrios Stamou ; Nora Ventosa
- 刊名：The Journal of the American Chemical Society
- 出版年：2012
- 出版时间：February 1, 2012
- 年：2012
- 卷：134
- 期：4
- 页码：1918-1921
- 全文大小：234K
- 年卷期：v.134,no.4(February 1, 2012)
- ISSN：1520-5126
文摘
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, Idye1 and Idye2, were assigned to each tracked vesicle, and their ratio, Idye1/Idye2, was used for quantifying the degree of membrane inhomogeneity between individual vesicles within each sample. A distribution of Idye1/Idye2 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.