1. Ultrasound-Driven Secondary Self-Assembly of Amphiphilic β-Cyclodextrin Dimers.
- Author
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Zhang, Hai-tao, Fan, Xiao-dong, Tian, Wei, Suo, Rong-tian, Yang, Zhen, Bai, Yang, and Zhang, Wan-bin
- Subjects
CYCLODEXTRINS ,DIMERS ,ULTRASOUND contrast media ,AMPHIPHILES ,LITHOCHOLIC acid ,HYDROPHOBIC compounds ,HYDROPHILIC compounds ,MICELLES - Abstract
The controlled secondary self-assembly of amphiphilic molecules in solution is theoretically and practically significant in amphiphilic molecular applications. An amphiphilic β-cyclodextrin (β-CD) dimer, namely LA-(CD)
2 , has been synthesized, wherein one lithocholic acid (LA) unit is hydrophobic and two β-CD units are hydrophilic. In an aqueous solution at room temperature, LA-(CD)2 self-assembles into spherical micelles without ultrasonication. The primary micelles dissociates and then secondarily form self-assemblies with branched structures under ultrasonication. The branched aggregates revert to primary micelles at high temperature. The ultrasound-driven secondary self-assembly is confirmed by transmission electron microscopy, dynamic light scattering,1 H NMR spectroscopy, and Cu2+ -responsive experiments. Furthermore, 2D NOESY NMR and UV/Vis spectroscopy results indicate that the formation of the primary micelles is driven by hydrophilic-hydrophobic interactions, whereas host-guest interactions promote the formation of the secondary assemblies. Additionally, ultrasonication is shown to be able to effectively destroy the primary hydrophilic-hydrophobic balances while enhancing the host-guest interaction between the LA and β-CD moieties at room temperature. [ABSTRACT FROM AUTHOR]- Published
- 2015
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