Controlled transformation from nanorods to vesicles induced by cyclomaltoheptaoses (β-cyclodextrins).

A modified cyclomaltoheptaose (β-cyclodextrin) containing an anthraquinone moiety, mono[6-deoxy-N-n-hexylamino-(N'-1-anthraquinone)]-β-cyclodextrin (1), which can self-assemble into nanorods in aqueous solution, was synthesized. Interestingly, upon the addition of natural cyclodextrin, the nanorods could transform into bilayer vesicles, which were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), and epi-fluorescence microscopy (EFM). A transformation mechanism is suggested based on the results of (1)H NMR, 2D NMR ROESY, FTIR, and UV-vis spectra. The response of the vesicles to changing pH and adding Cu(2+) was also tested. Our research may pave the way to the development of new intelligent materials and biomaterials. 2010 Elsevier Ltd. All rights reserved.