title: Transformation of micelles into supramolecular vesicles triggered by the formation of [4]pseudorotaxanes.
abstract: Spontaneous formation of supramolecular vesicles which are triggered by the formation of [4]pseudorotaxane B was demonstrated, whereas both Guest and [2]pseudorotaxane A, the precursors of [4]pseudorotaxane B, only assemble into micelles in DMF/water solution. The remarkable transformation of Guest from micelles to supramolecular vesicles was confirmed through DLS, TEM, and Cryo-TEM experiments. The cumulative release of a model drug, 5-carboxyfluorescein (CF), was used to determine the permeability of the supramolecular vesicles. No leakage of entrapped CF was observed within 48 h by fluorescence measurement, indicating the high stability of supramolecular vesicles. The formation mechanism of supramolecular vesicles self-assembled by [4]pseudorotaxane B was also discussed. In [4]pseudorotaxane B, CB[6] is used to increase the hydrophobic property of site β, which acts as hydrophobic "tail." Meanwhile, CB[7] plays the role of increasing "head area" of site α, which acts as hydrophilic "head." The synergistic effect of CB[6] and CB[7] induces the formation of supramolecular vesicles. Moreover, the effect of DMF content was investigated by TEM observations. It was found that the [4]pseudorotaxane B can self-assemble into regular supramolecular vesicles when the DMF content is in the range of 50-70%.
authors.affiliation: College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
authors.forename: Qiongbo
authors.initials: Q
authors.lastname: Zhou
authors.forename: Ding
authors.initials: D
authors.lastname: Gao
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Xuzhuo
authors.initials: X
authors.lastname: Sun
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Qi
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhang
authors.forename: Chunlan
authors.initials: C
authors.lastname: Xia
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Zhou
mesh_terms: D046911:Macromolecular Substances / Q000737:chemistry; D008823:Micelles; D008958:Models, Molecular; D015394:Molecular Structure; D010316:Particle Size; D043862:Rotaxanes / Q000138:chemical synthesis* / Q000737:chemistry; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008823:Micelles; D043862:Rotaxanes
keywords: Aggregation; Cucurbituril; Pseudorotaxane; Supramolecular vesicles; Transformation