PH-Induced Transition Between Single-Chain Macrocyclic Amphiphile and [c2]Daisy Chain-Based Bola-Type Amphiphile and the Related Self-Assembly Behavior in Water.

Pi Wang,Danyu Xia,Ruihuan Wang

doi:10.3389/fchem.2019.00894

Pi Wang, Danyu Xia + Show 1 more

Open Access

https://doi.org/10.3389/fchem.2019.00894

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Abstract

Macrocyclic amphiphiles, a type of amphiphiles synthesized based on macrocyclic compounds, have attracted much attention over the past decades due to their unique superiority in the construction of various functional nanomaterials. The regulation of the state of macrocyclic amphiphiles by introducing stimuli-responsive motif to macrocyclic amphiphiles is an efficient way to extend their applications in diverse fields. Herein, pillararene-based macrocyclic amphiphile H1 was prepared. H1 can act as single-chain amphiphile to self-assemble into micelles in water when the pH was ≥5.0. H1 can be protonated to turn into H2 when pH changed to <5.0. Interestingly, H2 formed [c2]daisy chain-based bola-type supramolecular amphiphile. This bola-type supramolecular amphiphile self-assembled into nanosheets in water. Therefore, pH-induced transition between single-chain macrocyclic amphiphile and bola-type amphiphile and the corresponding self-assembly system based on pillararene in water were constructed.

Highlights

Amphiphiles, carrying both hydrophilic and hydrophobic parts connected by covalent bonds, are a class of interesting molecules to fabricate self-assembly systems (Discher and Eisenberg, 2002; Sorrenti et al, 2013; Chang et al, 2019b)
Atomic force microscopy experiments were performed by a Bruker Multi-Mode 8.0 instrument
H1 can act as a single-chain amphiphile and self-assembled into micelles in water

Summary

Introduction

Amphiphiles, carrying both hydrophilic and hydrophobic parts connected by covalent bonds, are a class of interesting molecules to fabricate self-assembly systems (Discher and Eisenberg, 2002; Sorrenti et al, 2013; Chang et al, 2019b). Owing to their amphiphilic nature, amphiphiles can self-assemble into various nanostructures in water that can be applied in various areas, including drug/gene delivery, photodynamic therapy, and bioimaging (Zhang and Wang, 2011; Hu et al, 2013; Kelley et al, 2013; Ma and Zhao, 2015; Yu et al, 2015; Ji et al, 2016; Xia et al, 2016; Webber and Langer, 2017; Guo et al, 2018; Zuo et al, 2018; Wang S.-P. et al, 2019; Wang Y. et al, 2019). External stimuli-responsive macrocyclic amphiphiles play important roles in many fields, such as injectable materials, sensing, and cell imaging (Chang et al, 2014; Himmelein et al, 2014; Wang et al, 2015; Yang et al, 2016; Himmelein and Ravoo, 2017; Gao et al, 2018; Hu et al, 2018; Sun et al, 2018; Lee et al, 2019; Li et al, 2019)

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