Laboratoire Matière et Systèmes Complexes, UMR 7057, Université Paris Diderot, Sorbonne Paris Cité , 10 Rue Alice Domon et Léonie Duquet , 75205 Paris , France.
Plateforme Rayons X-UFR de Chimie, Université Paris Diderot , 35 rue Hélène Brion , 75205 Paris Cedex 13 , France.
J Phys Chem B. 2018 Jun 7;122(22):6055-6063. doi: 10.1021/acs.jpcb.8b01417. Epub 2018 May 25.
Cyclodextrins (CDs) are a family of oligosaccharides with a toroid shape, which exhibit a remarkable ability to include guest molecules in their internal cavity, providing a hydrophobic environment for poorly soluble molecules. Recently, new types of inclusions of α CDs with alkyl grafted polysaccharide chains (pullulan, chitosan, dextran, amylopectin, chondroitin sulfate...) have been prepared which are autoassembled into micro- and nanoplatelets. We report in this paper an extensive investigation of platelets with different compositions, including their reversible hydration (thermogravimetric analysis), crystalline structure (powder X-ray diffraction), dimensions and shapes (scanning electron microscopy-field emission gun), thermal properties, solubility, and melting (micro-differential scanning calorimetry). The crystalline platelets exhibit layered structures intercalating the polysaccharide backbones and CD complexes hosting the grafted alkyl chains. The monoclinic symmetry of columnar-type crystals suggests a head-to-tail arrangement of the CDs. The platelets have a preferentially hexagonal shape with sharp edges, variable sizes, and thicknesses and sometimes show incomplete layers (terraces). The crystal parameters change upon dehydration. Melting temperatures of platelets in aqueous solutions exceed 100 °C. Finally, we discuss the potential relation between the platelet structure and applications for mucoadhesive devices.
环糊精（CDs）是一类具有环形形状的低聚糖，它们具有将客体分子包含在其内部空腔中的显著能力，为疏水性较差的分子提供了疏水环境。最近，已经制备了具有烷基接枝多糖链（普鲁兰、壳聚糖、葡聚糖、支链淀粉、硫酸软骨素……）的α-CD 的新型包合物，这些包合物自组装成微纳米片。本文报告了对具有不同组成的片层的广泛研究，包括其可逆水合（热重分析）、晶体结构（粉末 X 射线衍射）、尺寸和形状（扫描电子显微镜-场发射枪）、热性能、溶解度和熔融（微差示扫描量热法）。结晶片层具有层状结构，其中嵌入多糖主链，并且包含接枝烷基链的 CD 配合物。柱状晶体的单斜对称性表明 CD 的头尾排列。片层具有优先的六边形形状，具有锐利的边缘、可变的尺寸和厚度，有时显示不完整的层（梯田）。脱水量的变化会导致晶体参数发生变化。水合溶液中片层的熔融温度超过 100°C。最后，我们讨论了片层结构与用于粘膜粘附装置的潜在关系。
