pH/ROS Dual-Responsive Supramolecular Vesicles Fabricated by Carboxylated Pillararene-Based Host–Guest Recognition and Phenylboronic Acid Pinacol Ester Derivative
journal contributionposted on 06.04.2020, 21:29 authored by Qi Hao, Yuetong Kang, Jiang-Fei Xu, Xi Zhang
The pH and reactive oxygen species (ROS) dual-responsive supramolecular vesicle utilizing a novel host–guest molecular recognition between a phenylboronic acid pinacol ester derivative carrying long alkyl chain (PBEC12A) and carboxylated pillararene (CP) is developed. The host–guest complexation between CP and PBEC12A was first studied in aqueous solution. PBEC12A was encapsulated within CP forming a stable host–guest complex with a binding constant as high as 106 M–1 order of magnitude. The driving force behind such a host–guest recognition was the combination of electrostatic interaction and hydrophobic effect. Then, the self-assembly of the supra-amphiphiles of PBEC12A-CP host–guest complexes was investigated in aqueous solution through high-resolution transmission electron microscope and dynamic light scattering. It was found that the supra-amphiphiles self-assembled into supramolecular vesicles and the size of the self-assembled supramolecular vesicles could be tuned from 25 to 200 nm by varying the ratio of CP to PBEC12A. To demonstrate the pH– and ROS-responsive properties of the self-assembled vesicles, the supramolecular vesicles self-assembled from PBEC12A/CP (5:1) were utilized. The Nile Red loading and release studies demonstrated that the supramolecular vesicles possessed good pH/ROS dual-responsive properties. This study enriches the field of supra-amphiphile based on noncovalent interactions. It is anticipated that the pH/ROS dual-responsive supramolecular vesicles have potential applications in drug-delivery systems because both the stimuli are in close relation with specific microenvironments of tumors and relevant diseases of the human body.