Amphiphilic Behavior and Membrane Solubility of a Dicholesteryl-Cyclodextrin

作者：Klaus Angelika; Fajolles Christophe^*; Bauer Martin; Collot Mayeul; Mallet Jean Maurice; Daillant Jean

来源：Langmuir, 2011, 27(12): 7580-7586.

DOI：10.1021/la200863c

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-(beta-cholesteryl)succinylamido-6I,6IV-(6-deoxy-per-(2,3,6-O-methyl))cycloheptaose (TBdSC) and how it inserts in dipalmitoyl-L-alpha-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.

• 出版日期2011-6-21
• 单位中国地震局