An Amphiphilic Pillar[5]arene: Synthesis, Controllable Self-Assembly in Water, and Application in Calcein Release and TNT Adsorption

Novel binding regioselectivity in the interpenetration of a non-symmetric axle into a non-symmetric pillar[5]arene wheel

A non-symmetric pillar[5]arene bearing methyl and pentyl rims can regioselectively bind 5-bromovaleronitrile, with the directionality of CN@methyl rim and Br@pentyl rim.

Construction of muscle-like metallo-supramolecular polymers from a pillar[5]arene-based [c2]daisy chain

A muscle-like metallo-supramolecular polymer based on a solvent-driven [c2]daisy chain has been prepared from an amino-modified pillar[5]arene. The integration of terpyridine moieties on both ends of the [c2]daisy chain and the stiff architecture of pillar[5]arene units facilitated the efficient formation of the metallo-supramolecular polymer.

Reversible assembly of silver nanoparticles driven by host–guest interactions based on water-soluble pillar[n]arenes

Water-soluble pillar[5]arene stabilized silver nanoparticles tend to assemble together upon addition of guest molecules due to the host–guest interactions. Further disassembly of AgNPs is realized by addition of a competitive host water-soluble pillar[6]arene which can form a stronger complex with G.

Controlling the self-assembly of cationic bolaamphiphiles: hydrotropic counteranions determine aggregated structures

The size and substitution pattern of hydrotropic counteranions determine the aggregated structures of cationic bolaamphiphiles.

Charge-transfer interactions for the fabrication of multifunctional viral nanoparticles

In this paper, a facile strategy to fabricate multifunctional viral nanoparticles was described by introducing charge-transfer interactions between a pyrenyl motif with dinitrophenyl and pyridinium-contained guest molecules.

An enzyme-responsive supra-amphiphile constructed by pillar[5]arene/acetylcholine molecular recognition

A novel molecular recognition motif between a water-soluble pillar[5]arene (WP5) and acetylcholine is established with an association constant of (5.05 ± 0.13) × 10⁴ M⁻¹.

Chemical-responsive control of lower critical solution temperature behavior by pillar[10]arene-based host–guest interactions

A new water-soluble thermoresponsive pillar[10]arene with tri(ethylene oxide) groups was synthesized and its cloud point could be reversibly controlled based on a chemical-responsive host–guest system.

Synergistically enhanced electrochemical response of host-guest recognition based on ternary nanocomposites: reduced graphene oxide-amphiphilic pillar[5]arene-gold nanoparticles

An amphiphilic pillar[5]arene (AP5) was modified onto the surface of reduced graphene oxide (RGO) to form the water-dispersive RGO-AP5 nanocomposite. And then, as-prepared gold nanoparticles (AuNPs) self-assembled onto the surface of RGO-AP5 through amido groups of AP5 to achieve RGO-AP5-AuNPs nanocomposites. It was verified that a large amount of AP5 molecules had been effectively loaded onto the surface of RGO and lots of AuNPs could be uniformly dispersed on RGO-AP5. Electrochemical results showed that the RGO-AP5 could exhibit selective supramolecular recognition and enrichment capability toward guest molecules. More significantly, in electrochemical sensing the guest molecules, ternary nanocomposites RGO-AP5-AuNPs performed the synergetic action of multifunctional properties, which were excellent performances of RGO, selective supramolecular recognition, and enrichment capability of AP5 and catalytic property of AuNPs for guest molecules. Therefore, RGO-AP5-AuNPs showed an outstanding analyzing performance for DA with broad linear range (1.5 × 10(-8) to 1.9×10(-5) M) and low detection limit (1.2 × 10(-8) M) at a signal-to-noise ratio of 3.

Self-assembly of nonionic surfactant Tween 20@2β-CD inclusion complexes in dilute solution

It has long been considered that the addition of cyclodextrins (CDs) disfavors the self-assembly of surfactants in dilute solutions since the hydrophobic effect is destroyed upon the formation of the hydrophiphilic CD/surfactant inclusion complex. However, in this work, we found that β-CD/nonionic surfactant inclusion complexes are able to self-assemble into vesicles in dilute solutions, namely in solutions with concentration lower than the CMC of surfactants. When using Tween 20 as a model surfactant, HNMR and MS measurements indicate that the building block for the vesicles is the channel type Tween 20@2β-CD inclusion complex. Structure and IR analysis suggests that the self-assembly of hydrophilic Tween 20@2β-CD is driven by H-bonds between both the headgroup of Tween 20 and the hydroxyl groups of β-CD. The self-assembly of the inclusion complex between the β-CD and the nonionic surfactant in dilute solution is found to be a general phenomenon. Undoubtedly, surfactant@2β-CD inclusion complex can be a novel building block for nonamphiphilic self-assembly, which provides a new physical insight for the influence of cyclodextrins on the self-assembly of surfactants.

Mechanized silica nanoparticles based on pillar[5]arenes for on-command cargo release

Mechanized silica nanoparticles, equipped with pillar[5]arene-[2]pseudorotaxane nanovalves, operate in biological media to trap cargos within their nanopores, but release them when the pH is lowered or a competitive binding agent is added. Although cargo size plays an important role in cargo loading, cargo charge-type does not appear to have any significant influence on the amount of cargo loading or its release. These findings open up the possibility of using pillar[n]arene and its derivatives for the formation of robust and dynamic nanosystems that are capable of performing useful functions.

Biocompatible pillararene-assembly-based carriers for dual bioimaging

Present research provides a successful example to use biocompatible pillararene-based assemblies for delivering mixed dyes in dual bioimaging. A series of tadpole-like and bola amphiphilic pillararenes 1-4 were synthesized by selectively employing water-soluble ethylene glycols and hydrophobic alkyl units as the starting materials. In comparison with their monomers, these amphiphilic pillararenes not only show improved biocompatibility to cells but also could form homogeneous supramolecular self-assemblies. Interestingly, different types of amphiphilic pillararene-based assemblies exhibit various performances on the delivery of dyes with different aqueous solubility. All assemblies can deliver water-soluble rhodamine B to cells, while only tadpole-like amphiphilic pillararene-based assemblies performed better on delivering hydrophobic fluorescein isothiocyanate for imaging. In addition, pillararene derivatives 1, 3, and 4 could complex with a viologen guest, further forming stable assemblies for bioimaging. In such cases, the assembly formed from the complex of tadpole-like amphiphile pillararene 1 with the viologen guest performed better in delivering mixed dyes. Finally, an anticancer drug, doxorubicin, was successfully delivered to cells by using the pillararene-based assemblies. The current research has determined the capacities of pillararene-based assemblies to deliver different dyes for bioimaging and paves the way for using these biocompatible carriers toward combined cancer therapy.

Hierarchical self-assembly: well-defined supramolecular nanostructures and metallohydrogels via amphiphilic discrete organoplatinum(II) metallacycles

Metallacyclic cores provide a scaffold upon which pendant functionalities can be organized to direct the formation of dimensionally controllable nanostructures. Because of the modularity of coordination-driven self-assembly, the properties of a given supramolecular core can be readily tuned, which has a significant effect on the resulting nanostructured material. Herein we report the efficient preparation of two amphiphilic rhomboids that can subsequently order into 0D micelles, 1D nanofibers, or 2D nanoribbons. This structural diversity is enforced by three parameters: the nature of the hydrophilic moieties decorating the parent rhomboids, the concentration of precursors during self-assembly, and the reaction duration. These nanoscopic constructs further interact to generate metallohydrogels at high concentrations, driven by intermolecular hydrophobic and π-π interactions, demonstrating the utility of coordination-driven self-assembly as a first-order structural element for the hierarchical design of functional soft materials.

pH-responsive supramolecular vesicles based on water-soluble pillar[6]arene and ferrocene derivative for drug delivery

The drug delivery system based on supramolecular vesicles that were self-assembled by a novel host-guest inclusion complex between a water-soluble pillar[6]arene (WP6) and hydrophobic ferrocene derivative in water has been developed. The inclusion complexation between WP6 and ferrocene derivative in water was studied by (1)H NMR, UV-vis, and fluorescence spectroscopy, which showed a high binding constant of (1.27 ± 0.42) × 10(5) M(-1) with 1:1 binding stoichiometry. This resulting inclusion complex could self-assemble into supramolecular vesicles that displayed a significant pH-responsive behavior in aqueous solution, which were investigated by fluorescent probe technique, dynamic laser scattering, and transmission electron microscopy. Furthermore, the drug loading and in vitro drug release studies demonstrated that these supramolecular vesicles were able to encapsulate mitoxantrone (MTZ) to achieve MTZ-loaded vesicles, which particularly showed rapid MTZ release at low-pH environment. More importantly, the cellular uptake of these pH-responsive MTZ-loaded vesicles by cancer cells was observed by living cell imaging techniques, and their cytotoxicity assay indicated that unloaded vesicles had low toxicity to normal cells, which could dramatically reduce the toxicity of MTZ upon loading of MTZ. Meanwhile, MTZ-loaded vesicles exhibited comparable anticancer activity in vitro as free MTZ to cancer cells under examined conditions. This study suggests that such supramolecular vesicles have great potential as controlled drug delivery systems.

A sugar-functionalized amphiphilic pillar[5]arene: synthesis, self-assembly in water, and application in bacterial cell agglutination

A novel sugar-functionalized amphiphilic pillar[5]arene containing galactose groups as the hydrophlic part and alkyl chains as the hydrophobic part was designed and synthesized. It self-assembles in water to produce nanotubes as confirmed by TEM, SEM, and fluorescence microscopy. These nanotubes, showing low toxicity to both cancer and normal cells, can be utilized as excellent cell glues to agglutinate E. coli. The existence of galactoses on these nanotubes provides multivalent ligands that have high affinity for carbohydrate receptors on E. coli.