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Ultrasound‐Driven Secondary Self‐Assembly of Amphiphilic β‐Cyclodextrin Dimers
Author(s) -
Zhang Haitao,
Fan Xiaodong,
Tian Wei,
Suo Rongtian,
Yang Zhen,
Bai Yang,
Zhang Wanbin
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201405707
Subject(s) - amphiphile , micelle , dynamic light scattering , chemistry , self assembly , sonication , molecule , hydrophobic effect , cyclodextrin , aqueous solution , dimer , spectroscopy , protein secondary structure , two dimensional nuclear magnetic resonance spectroscopy , nuclear magnetic resonance spectroscopy , crystallography , copolymer , organic chemistry , polymer chemistry , materials science , stereochemistry , nanoparticle , nanotechnology , polymer , chromatography , biochemistry , physics , quantum mechanics
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 Cu 2+ ‐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.