Consequences of ions and pH on the supramolecular organization of sphingomyelin and sphingomyelin/cholesterol bilayers |
| |
Authors: | Chemin Caroline Bourgaux Claudie Péan Jean-Manuel Pabst Georg Wüthrich Patrick Couvreur Patrick Ollivon Michel |
| |
Institution: | Université Paris Sud, UMR CNRS 8612, Chatenay-Malabry, France. caroline.chemin@fr.netgrs.com |
| |
Abstract: | For drug delivery purpose the anticancer drug S12363 was loaded into ESM/Chol-liposomes using either a pH or an ammonium gradient. Association between the drug and the liposome depends markedly on the liposome membrane structure. Thus, ESM and ESM/Chol bilayer organization had been characterized by coupled DSC and XRDT as a function of both cholesterol concentration and aqueous medium composition. ESM bilayers exhibited a ripple lamellar gel phase P(beta') below the melting temperature and adopted a L(beta)-like gel phase upon Chol insertion. Supramolecular organization of ESM and ESM/Chol bilayers was not modified by citrate buffer or ammonium sulfate solution whatever the pH (3< or = pH < or =7). Nevertheless, in ESM bilayer, ammonium sulfate salt induced a peculiar organization of head groups, leading to irregular d-spacing and weakly correlated bilayers. Moreover, in the presence of salts, a weakening of van der Waals attraction forces was seen and led to a swelling of the water layer. |
| |
Keywords: | Differential scanning calorimetry (DSC) X-ray diffraction (XRD) pH Ion Egg sphingomyelin (ESM) Cholesterol (Chol) |
本文献已被 ScienceDirect PubMed 等数据库收录! |