title: Amphiphilic behavior and membrane solubility of a dicholesteryl-cyclodextrin.
abstract: Amphiphilic cyclodextrins (CDs) are good candidates to functionalize natural membranes as well as synthetic vesicles. In this paper, we provide a full description of the interfacial behavior of pure 6I,6IV-(β-cholesteryl)succinylamido-6I,6IV-(6-deoxy-per-(2,3,6-O-methyl))cycloheptaose (TBdSC) and how it inserts in dipalmitoyl-l-α-phosphatidylcholine (DPPC) monolayers as a membrane model. Langmuir isotherms of pure TBdSC suggest a reorganization upon compression, which could be clarified using X-ray reflectivity. The CD head can adjust its conformation to the available area per molecule. A compatible model involving a rotation around a horizontal axis defined by the two selectively substituted glucose units is proposed. The in-plane structure is characterized at all scales by Brewster angle microscopy (BAM) on the water surface and atomic force microscopy (AFM) on monolayers deposited on solid substrates. The same tools are used for its mixtures with DPPC. We show in particular that TBdSC seems to be soluble in the liquid-expanded DPPC. However, phase segregation occurs at higher pressure, allowing for sequentially liquid-condensed DPPC and high-pressure conformation of TBdSC. This gives rise to a remarkable contrast inversion in both imaging methods.
authors: UMR 3299 Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA)/Centre National de la Recherche Scientifique (CNRS), SIS2M, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), CEA Saclay, 91191 Gif sur Yvette, France.
authors: Angelika
authors: A
authors: Klaus
authors: Christophe
authors: C
authors: Fajolles
authors: Martin
authors: M
authors: Bauer
authors: Mayeul
authors: M
authors: Collot
authors: Jean-Maurice
authors: JM
authors: Mallet
authors: Jean
authors: J
authors: Daillant