pH/ROS Dual-Responsive Supramolecular Vesicles Fabricated by Carboxylated Pillar[6]arene-Based Host–Guest Recognition and Phenylboronic Acid Pinacol Ester Derivative

Abstract

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 pillar[6]­arene (CP[6]) is developed. The host–guest complexation between CP[6] and PBEC12A was first studied in aqueous solution. PBEC12A was encapsulated within CP[6] 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[6] 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[6] to PBEC12A. To demonstrate the pH– and ROS-responsive properties of the self-assembled vesicles, the supramolecular vesicles self-assembled from PBEC12A/CP­[6] (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.

Enzyme-Responsive Molecular Assemblies Based on Host–Guest Chemistry

“…CDs are macrocyclic compounds and considered biologically safe. Recent studies have shown that CDs are able to form host–guest complexes by associating with a vast number of commercially available materials. − In particular, we demonstrated previously that β-CD-amphiphile complexes can further assemble into diverse structures, including vesicles, − tubes, − lamellae, − helical ribbons, and rhombics . Because 1,4-glycosidic bonds in CDs can be cleaved by α-amylase, , we are able to construct the CD-based molecular assemblies that may serve as a versatile platform for the development enzyme-responsive systems, especially in the construction of enzyme-responsive assemblies that exhibit structural transitions.…”

Supramolecular vesicle engineering by regulating the assembly of shape-persistent aromatic-hydrazone macrocycles

“…[29][30][31] If the assembly of supramolecular building blocks can be manipulated, the sizes and properties of supramolecular vesicles may be controlled. [32][33][34][35] However, understanding the relationship between vesicle size and the corresponding assembly of supramolecular building blocks is still a challenge.…”

Fabrication of poly methylacrylate acid hybrid silica core‐shell microspheres with redox responsive biodegradability for drug delivery

“…4 With the use of stimuli-responsive bonds, DDSs could stay stable during blood circulation after administration to minimize the side effects caused by drug leakage and achieve TME responsive drug release to ensure high bioavailability. 5,6 To overcome the drawbacks of traditional chemotherapy, several DDSs have been developed, including nanoparticles, [7][8][9][10][11][12][13][14] micelles, 15 and hydrogel. 16 Mesoporous silica nanoparticle (MSNP) based biomaterials are one of the most promising platforms in constructing DDSs, due to their ease of fabrication, mesoporous structure, and a large amount of surface functional groups.…”

“…To overcome the drawbacks of traditional chemotherapy, several DDSs have been developed, including nanoparticles, 7–14 micelles, 15 and hydrogel 16 . Mesoporous silica nanoparticle (MSNP) based biomaterials are one of the most promising platforms in constructing DDSs, due to their ease of fabrication, mesoporous structure, and a large amount of surface functional groups 17–19 .…”