Molecular engineering of polymeric supra-amphiphiles

Detecting Pb2+ in aqueous environment and live cells by amphiphilic pillar[5]arene-assembled supramolecular sensor based on host-guest charge transfer mechanism

Water-soluble fluorescent chemosensors for lead ion are highly desirable in environmental detection and bioimagery. Based on a water-soluble pillar[5]arene WP5 and imidazolium terminal functionalized 2,2'-bibenzimidazole derivative BIHB, we report a host-guest charge transfer assembly BIHB-2WP5 for sensitive and selective detection of Pb2+ in pure aqueous media. As a result of its high electron-rich cavity, WP5 can bind electron-deficiency guest BIHB with various host/guest stoichiometry to easily tune the microtopography of assembly from nanoparticle to nanocube. In view of the good biocompatibility and sensitivity, the supramolecular assembly BIHB-2WP5 was used as a fluorescent probe for the detection of Pb2+ in living cells and a smartphone Pb2+ detection device was constructed for the in situ test.

Gas-Controlled Self-Assembly of Metallacycle-Cored Supramolecular Star Polymer with Tunable Antibacterial Activity

Herein, a three-armed amphiphilic metallacycle-cored star supramolecular polymer (Por-MOM-PDMAEMA) has been designed and synthesized via highly efficient post-assembly polymerization. This star polymer is further self-assembled into nanoparticles of different sizes depending upon the experimental conditions. The gas-controlled morphology transformation and tunable antibacterial activities of Por-MOM-PDMAEMAis systematically investigated and compared with metallacycle (MOM). The superior antibacterial activity of Por-MOM-PDMAEMA against multidrug-resistant P. aeruginosa implies that the presence of photodynamic photosensitizer (Por) and cationic polymer chain will significantly enhance antibactericidal activity, which is mainly attributed to the synergistic effect of photosensitizer and polymer chain linked in one metallacycle core. By leveraging the unique properties of metallacycle and their dynamic response to gaseous stimuli, the antibacterial properties of the Por-MOM-PDMAEMA can be finely tuned in response to gas triggers.

Chiral Effect on the Electrochemistry of Magnetic Ferrite Colloidal Nanocrystal Assembly Modified by Amino Acids

Chirality on the molecular or nanometer scale is particularly significant in chemistry, materials science, and biomedicine. Chiral electrochemical reactions on solid surfaces are currently a hot research topic. Herein, a chiral solid surface is constructed in aqueous solutions by mixing chiral molecules, d- and l-glutamic, with γ-Fe2O3 and Fe3O4 nanoparticles (NPs) and MnFe2O4 colloidal nanocrystal assembly (CNA). Cyclic voltammetry and differential pulse voltammetry measurements are conducted in a phosphate buffer solution (PBS) containing ascorbic acid (AA) or isoascorbic acid (IAA), and a chiral effect appears on the electroreduction of ferric ions of amino acid-modified magnetic samples. A negative or positive potential shift is observed, respectively, for magnetic structures modified by l- and d-glutamic acid in aqueous AA electrolyte, while the opposite is observed for these samples in IAA electrolyte. The reduction peak current increases by 0.8-1.2 times for the electrodes modified with l- and d-glutamate molecules, improving the electron transport efficiency. The chiral effect is absent when the electrolytes contain achiral uric acid or dopamine, or even chiral l-/d-/ld-tartaric acid. The chiral recognition between d-/l-glutamic acid and AA/IAA at the electrochemical interface is suggested to be related to their spinal configurations. These observations will be helpful for the rational design of inorganic functional chiral micro/nanostructures.

ON-OFF Control of Marangoni Self-propulsion via A Supra-amphiphile Fuel and Switch

Marangoni self-propulsion refers to motion of liquid or solid driven by a surface tension gradient, and has applications in soft robots/devices, cargo delivery, self-assembly etc. However, two problems remain to be addressed for motion control (e.g., ON-OFF) with conventional surfactants as Marangoni fuel: (1) limited motion lifetime due to saturated interfacial adsorption of surfactants; (2) in- situ motion stop is difficult once Marangoni flows are triggered. Instead of covalent surfactants, supra-amphiphiles with hydrophilic and hydrophobic parts linked noncovalently, hold promise to solve these problems owing to its dynamic and reversible surface activity responsively. Here, we propose a new concept of 'supra-amphiphile fuel and switch' based on the facile synthesis of disodium-4-azobenzene-amino-1,3-benzenedisulfonate (DABS) linked by a Schiff base, which has amphiphilicity for self-propulsion, hydrolyzes timely to avoid saturated adsorption, and provides pH-responsive control over ON-OFF motion. The self-propulsion lifetime is extended by 50-fold with DABS and motion control is achieved. The mechanism is revealed with coupled interface chemistry involving two competitive processes of interfacial adsorption and hydrolysis of DABS based on both experiments and simulation. The concept of 'supra-amphiphile fuel and switch' provides an active solution to prolong and control Marangoni self-propulsive devices for the advance of intelligent material systems.

Intercage Polymerization of Postfunctionalized Phosphine Organic Prisms into Cage-Based Assemblies with Tunable Morphologies

Great effort has been dedicated to the engineering of porous organic cages (POCs) in geometry and topology. Yet, harnessing these cage-like entities as premade building units to construct infinite cage-based superstructures remains elusive. In this study, we design a type of vertex-modified phosphine organic prism by a postfunctionalized approach and use it as a ditopic cage monomer to achieve an intercage supramolecular polymerization via the synergy of metal coordination and π-π dimerization. The resulting cage-by-cage polymers can further hierarchically organize into superstructures of diverse morphologies and dimensionalities, including 1D fibers, 2D lamellae, and 3D vesicles. Control over the cosolvents is capable of well regulating their structural hierarchies and self-assembled shapes. This would pave a way for the creation of cage-based supramolecular assemblies and nanomaterials.

Polarization-Dependent Thin Films with Biaxial Anisotropic Absorption Constructed by a Single Coating and Subsequent Topochemical Polymerization of Chromophores

For the construction of hierarchical superstructures with biaxial anisotropic absorption, a newly synthesized diacetylene-functionalized bipyridinium is self-assembled to use an electron-accepting host for capturing and arranging guests. The formation of the donor-acceptor complex triggers an intermolecular charge transfer, leading to chromophore activation. Polarization-dependent multichroic thin films are prepared through a sequential process of single-coating, self-assembly, and topochemical polymerization of host-guest chromophores. Molecular packing structures constructed in the single-layer optical thin film possess orthogonal absorption axes for two different wavelengths. By tuning the linear polarization angle, the color of the optical thin film can be intentionally controlled. This single-layered multichroic film provides a new pathway for the development of anticounterfeiting and multiplexing encryptions.

Self-Assembly of Polyoxometalate-Based Nanoparticle Surfactants in Solutions

Nanoparticle surfactants (NPSs) are an emergent class of amphiphiles attractive for their controllable assembly at the liquid-liquid interface. In this work, intriguing self-assembly behavior and stimuli-responsiveness of NPSs in homogeneous solutions are presented. With β-cyclodextrin-grafted polyoxometalates (POMs) and ferrocene (or azobenzene)-terminated polystyrene in water/tetrahydrofuran, POM-based NPSs are formed via host-guest interactions and self-organize to vesicles driven by solvent-phobic effects. The tunable supramolecular interactions allow these assemblies to be responsive to redox or light stimulus, respectively, affording an on-demand assembly/disassembly capacity that shows promise in delivery and release applications.

Smart organic materials based on macrocycle hosts

Innovative design of smart organic materials is of great importance for the advancement of modern technology. Macrocycle hosts, possessing cyclic skeletons, intrinsic cavities, and specific guest binding properties, have demonstrated pronounced potential for the elaborate fabrication of a variety of functional organic materials with smart stimuli-responsive characteristics. In this tutorial review, we outline the current development of smart organic materials based on macrocycle hosts as key building blocks, focusing on the design principles and functional mechanisms of the tailored systems. Three main types of macrocycle-based smart organic materials are exemplified as follows according to the distinct forms of construction patterns: (1) supramolecular polymeric materials and nanoassemblies; (2) adaptive molecular crystals; (3) smart porous organic materials. The responsive performances of macrocycle-containing smart materials in versatile aspects, including mechanically adaptive polymers, soft optoelectronic devices, data encryption, drug delivery systems, artificial transmembrane channels, crystalline-state gas adsorption/separation, and fluorescence sensing, are illustrated by discussing the representative studies as paradigms, where the roles of macrocycles in these systems are highlighted. We also provide in the conclusion part the perspectives and remaining challenges in this burgeoning field.

Combined Amphiphilic Silybin Meglumine Nanosuspension Effective Against Hepatic Fibrosis in Mice Model

Introduction

Silybin (SLB) as an effective hepatoprotective phytomedicine has been limited by its hydrophobicity, poor bioavailability and accumulation at lesion sites. Additionally, present drug loading methods are impeded by their low drug loading capacity, potential hazard of materials and poor therapeutic effects. Consequently, there is a pressing need to devise an innovative approach for preparing nanosuspensions loaded with both SLB and Silybin Meglumine salt (SLB-M), as well as to investigate the therapeutic effects of SLB nanosuspensions against hepatic fibrosis.

Methods

The SLB nanosuspension (NS-SLB) was prepared and further modified with a hyaluronic acid-cholesterol conjugate (NS-SLB-HC) to improve the CD44 targeting proficiency of NS-SLB. To validate the accumulation of CD44 and ensure minimal cytotoxicity, cellular uptake and cytotoxicity assessments were carried out for the nanosuspensions. Western blotting was employed to evaluate the anti-hepatic fibrosis efficacy in LX-2 cells by inhibiting the secretion of collagen I. Hepatic fibrosis mouse models were used to further confirm the effectiveness of NS-SLB and NS-SLB-HC against hepatic fibrosis in vivo.

Results

Uniform nanosuspensions were prepared through self-assembly, achieving high drug loading rates of 89.44% and 60.67%, respectively. Both SLB nanosuspensions showed minimal cytotoxicity in cellular environments and mitigated hepatic fibrosis in vitro. NS-SLB-HC was demonstrated to target activated hepatic stellate cells by receptor-ligand interaction between HA and CD44. They can reverse hepatic fibrosis in vivo by downregulating TGF-β and inhibiting the secretion of α-SMA and collagen I.

Conclusion

Designed as a medical excipient analogue, SLB-M was aimed to establish an innovative nanosuspension preparation method, characterized by high drug loading capacity and a notable impact against hepatic fibrosis.

Enzymatic polymerization of enantiomeric L-3,4-dihydroxyphenylalanine into films with enhanced rigidity and stability

_L-3,4-dihydroxyphenylalanine is an important molecule in the adhesion of mussels, and as an oxidative precursor of natural melanin, it plays an important role in living system. Here, we investigate the effect of the molecular chirality of 3,4-dihydroxyphenylalanine on the properties of the self-assembled films by tyrosinase-induced oxidative polymerization. The kinetics and morphology of pure enantiomers are completely altered upon their co-assembly, allowing the fabrication of layer-to-layer stacked nanostructures and films with improved structural and thermal stability. The different molecular arrangements and self-assembly mechanisms of the _L+D-racemic mixtures, whose oxidation products have increased binding energy, resulting in stronger intermolecular forces, which significantly increases the elastic modulus. This study provides a simple pathway for the fabrication of biomimetic polymeric materials with enhanced physicochemical properties by controlling the chirality of monomers.

Green-step assembly of the supramolecular amphiphile constructed by sodium carboxymethyl cellulose and calixarene for facile loading of hydrophobic food bioactive compounds

The use of biologically active compounds is often limited due to their poor aqueous solubility, which generally reduces their bioavailability and useful efficacy. In this regard, a wide search is currently underway for colloidal systems capable of encapsulating these compounds. In the creation of colloidal systems, long-chain molecules of surfactants and polymers are mainly used, which in an individual state do not always aggregate into homogeneous and stable nanoparticles. In the present work, cavity-bearing calixarene was used for the first time to order polymeric molecules of sodium carboxymethyl cellulose. A set of physicochemical methods demonstrated the spontaneous formation of spherical nanoparticles by non-covalent self-assembly contributed by macrocycle and polymer, and formed nanoparticles were able to encapsulate hydrophobic quercetin and oleic acid. The preparation of nanoparticles by supramolecular self-assembly without use of organic solvents, temperature and ultrasound effects can be an effective strategy for creating water-soluble forms of lipophilic bioactive compounds.

Light-adjusted supramolecular host-guest interfacial recognition for reconfiguring soft colloidal aggregates

The soft interfacial template-assisted confined self-assembly of block copolymers (BCPs) guiding colloidal aggregates has been extensively investigated by interfacial instability. Whether the macromolecular polymer architectonics possessed stimulus-responsive self-regulated structural controllability more readily implement the morphological diversity of colloidal aggregates. Herein, we in-situ constructed the alginate-modified β-cyclodextrin/azobenzene-functionalized alkyl chains (Alg-β-CD/AzoC12) system by supramolecular host-guest interfacial recognition-engineered strategy, in which possessed photo-stimulated responsive structural reconfigurability by modulating assembly/disassembly behaviors between CD and Azo at oil/water interface. The host-guest droplet interfaces acted as soft templates managing interfacial instability by synergistically integrating supra-amphiphilic host-guest polymers with cosurfactants, further constructing various soft supracolloidal aggregates, including soft nanoaggregates, microspheres with tunable degrees of surface roughness. Additionally, the stimuli-altering structural reconfigurability of supramolecular host-guest polymers was regulated by ultraviolet/visible irradiation, endowing soft aggregates with structural diversity. It's highly anticipated that the supramolecular host-guest interfacial recognition self-assembly establishes great bridge between supramolecular host-guest chemistry and colloid interface science.

Supramolecular interaction enabled preparation of high-strength water-based adhesives from polymethylmethacrylate wastes

The preparation of water-based adhesives with high bonding strength for various substrates is challenging. Moreover, to construct a sustainable society, it is highly desirable to develop a cost-effective way to achieve the reuse of plastic wastes. Herein, using polymethylmethacrylate (PMMA) chemicals or wastes as raw materials, water-based adhesives with high bonding strength for various substrates are prepared through a simple one-step hydrolysis strategy. The adhesives possess the maximum bonding strength of 7.1 MPa to iron, 4.2 MPa to wood, and ∼1.5 MPa to plastics. The adhesives have a world-record bonding strength to metal when compared with that of current reported water-based adhesives. Our method is low cost, simple, environmentally friendly, and suitable for large-scale industrial production. More importantly, using plastic wastes as raw materials opens up a new and low-cost way to turn wastes into valuables, which will greatly contribute to construct a sustainable society.

Chiral-engineered supraparticles: Emerging tools for drug delivery

The handedness of chiral-engineered supraparticles (CE-SPs) influences their interactions with cells and proteins, as evidenced by the increased penetration of breast, cervical, and myeloma cell membranes by d-chirality-coordinated SPs. Quartz crystal dissipation and isothermal titration calorimetry have been used to investigate such chiral-specific interactions. d-SPs are more thermodynamically stable compared with l-SPs in terms of their adhesion. Proteases and other endogenous proteins can be shielded by the opposite chirality of d-SPs, resulting in longer half-lives. Incorporating nanosystems with d-chirality increases uptake by cancer cells and prolongs in vivo stability, demonstrating the importance of chirality in biomaterials. Thus, as we discuss here, chiral nanosystems could enhance drug delivery systems, tumor markers, and biosensors, among other biomaterial-based technologies, by allowing for better control over their features.

Cyclodextrin-mediated conjugation of macrophage and liposomes for treatment of atherosclerosis

Current pharmacological treatments of atherosclerosis often target either cholesterol management or inflammation management, to inhibit atherosclerotic progression, but cannot lead to direct plaque lysis and atherosclerotic regression, partly due to the poor accumulation of medicine in the atherosclerotic plaques. Due to enhanced macrophage recruitment during atheromatous plaque progression, a facilely macrophage-liposome conjugate was constructed for targeted anti-atherosclerosis therapy via synergistic plaque lysis and inflammation alleviation. Endogenous macrophage is utilized as drug-transporting cell, upon membrane-modification with β-cyclodextrin (β-CD) derivative to form β-CD decorated macrophage (CD-MP). Adamantane (ADA) modified quercetin (QT)-loaded liposome (QT-NP), can be conjugated to CD-MP via host-guest interactions between β-CD and ADA to construct macrophage-liposome conjugate (MP-QT-NP). Thus, macrophage carries liposome "hand-in-hand" to significantly increase the accumulation of anchored QT-NP in the aorta plaque in response to the plaque inflammation. In addition to anti-inflammation effects of QT, MP-QT-NP efficiently regresses atherosclerotic plaques from both murine aorta and human carotid arteries via CD-MP mediated cholesterol efflux, due to the binding of cholesterol by excess membrane β-CD. Transcriptome analysis of atherosclerotic murine aorta and human carotid tissues reveal that MP-QT-NP may activate NRF2 pathway to inhibit plaque inflammation, and simultaneously upregulate liver X receptor to promote cholesterol efflux.

Adsorption-Based Detoxification of Endotoxins by Porous Flexible Organic Frameworks

Bacterial lipopolysaccharides (LPS, endotoxins) cause sepsis that is responsible for a huge amount of mortality globally. However, their neutralization or detoxification remains an unmet medical need. We envisaged that cationic organic frameworks with persistent hydrophobic porosity may adsorb and thus neutralize LPS through a combination of cooperative ion-pairing electrostatic attraction and hydrophobicity. We here report the preparation of two water-soluble flexible organic frameworks (FOF-1 and FOF-2) from tetratopic and ditopic precursors through quantitative formation of hydrazone bonds at room temperature. The two FOFs are revealed to possess hydrodynamic diameters, which range from 20 to 120 nm, depending on the concentrations. Dynamic light scattering and isothermal titration calorimetric and chromogenic limulus amebocyte lysate experiments indicate that both frameworks are able to adsorb and thus reduce the concentration of free LPS molecules in aqueous solution, whereas cytokine inhibition experiments with RAW264.7 support that this adsorption can significantly decrease the toxicity of LPS. In vivo experiments with mice (five males per group) show that the injection of FOF-1 at a dose of 0.6 mg/kg realizes the survival of all of the mice administrated with LPS of the d-galactosamine (d-Gal)-sensitized absolute lethal dose (LD₁₀₀, 0.05 mg/kg), whereas its maximum tolerated dose for mice is determined to be 10 mg/kg. These findings provide a new promising sequestration strategy for the development of porous agents for the neutralization of LPS.

Programmed Macromolecular Assembly by Dipole-Dipole Interactions with Aggregation-Induced Enhanced Emission in Aqueous Medium

Self-assembling polymers by bioinspired directional supramolecular interactions currently hold great scientific and technological interests. Herein, we report an unorthodox strategy based on a dipole-dipole interaction-mediated extended antiparallel dipolar assembly of a model merocyanine (MC) dye for maneuvering the self-assembly of a highly water-soluble MC-functionalized block copolymer (P2). Unlike traditional amphiphilic block copolymers featuring distinct hydrophobic segments (flexible aliphatic hydrocarbon chains or rigid nonpolar aromatic scaffolds), P2 comprises polyethylene glycol monomethyl ether (PEG) as a hydrophilic block and an unconventional structure-directing acrylate block functionalized with polar MC-dyes in the side chains of every repeat unit. In the absence of any additional hydrophobic assistance, P2 spontaneously self-assembles in water through the continuous opposite alignment of its pendant MCs by multiple dipole-dipole interactions to cancel out their ground state dipole moments, which initially generates an H-aggregated species with ill-defined morphology (Aggregate 1). Upon thermal annealing, Aggregate 1 reorganizes into higher-order core-shell nanodisc-like structures (Aggregate 2) driven by the orthogonal π-stacking interactions of the rigid aromatic framework derived from the extended cofacial MC-stacks. The aromatic interiors of the nanodiscs gain colloidal stability from the externally decorated hydrophilic PEG chains. While the initially formed Aggregate 1, predominantly by dipole-dipole interactions, showed remarkable thermal stability due to the cooperative effect of the polymer chain, the hierarchical assembly guided by relatively weaker dispersion forces of the MC-stacked π-surfaces could be tailored by dilution or thermal treatment. Such organized packing of pendant MCs by the dual effect of dipole-dipole interactions and π-stacking conferred several exciting properties to the P2 assembly in water. Long-range ordered antiparallel stacking of the pendant MCs rendered outstanding aggregation-induced enhanced emission (AIEE) properties to the resultant nanostructures in water with increased fluorescence lifetime, quantum yield, and Stokes shift compared to nonaggregating P2 in CHCl₃. The remarkable thermal and kinetic stability of the nanodiscs, their guest loading ability, and very low critical aggregation concentration (CAC) were demonstrated by Förster resonance energy transfer (FRET) studies with an encapsulated donor-acceptor dye pair.

Fabrication of Host-Guest Complexes between Adamantane-Functionalized 1,3,4-Oxadiazoles and β-Cyclodextrin with Improved Control Efficiency against Intractable Plant Bacterial Diseases

Supramolecular chemistry provides huge potentials and opportunities in agricultural pest management. In an attempt to develop highly bioactive, eco-friendly, and biocompatible supramolecular complexes for managing intractable plant bacterial diseases, herein, a type of interesting adamantane-functionalized 1,3,4-oxadiazole was rationally prepared to facilitate the formation of supramolecular complexes via β-cyclodextrin-adamantane host-guest interactions. Initial antibacterial screening revealed that most of these adamantane-decorated 1,3,4-oxadiazoles were obviously bioactive against three typically destructive phytopathogens. The lowest EC₅₀ values could reach 0.936 (III₁₈), 0.889 (III₁₈), and 2.10 (III₁₉) μg/mL against the corresponding Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Pseudomonas syringae pv. actinidiae (Psa). Next, the representative supramolecular binary complex III₁₈@β-CD (binding mode 1:1) was successfully fabricated and characterized by ¹H nuclear magnetic resonance (NMR), isothermal titration calorimetry (ITC), high-resolution mass spectrometry (HRMS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Eventually, correlative water solubility and foliar surface wettability were significantly improved after the formation of host-guest assemblies. In vivo antibacterial evaluation found that the achieved supramolecular complex could distinctly alleviate the disease symptoms and promote the control efficiencies against rice bacterial blight (from 34.6-35.7% (III₁₈) to 40.3-43.6% (III₁₈@β-CD)) and kiwi canker diseases (from 41.0-42.3% (III₁₈) to 53.9-68.0% (III₁₈@β-CD)) at 200 μg/mL (active ingredient). The current study can provide a feasible platform and insight for constructing biocompatible supramolecular assemblies for managing destructive bacterial infections in agriculture.

Chiral graphene-based supramolecular hydrogels toward tumor therapy

Drugs with chiral property are playing very important role on precise treatment of diseases (especially antitumor drugs), however, enantioselective delivery of chiral anticancer drugs is still challenge. Herein, a chiral...

Supramolecular Drug Delivery System from Macrocycle-Based Self-Assembled Amphiphiles for Effective Tumor Therapy

Intelligent drug delivery systems (DDSs) that can improve therapeutic outcomes of antitumor agents and decrease their side effects are urgently needed to satisfy special requirements of treatment of malignant tumors in clinics. Here, the fabrication of supramolecular self-assembled amphiphiles based on the host-guest recognition between a cationic water-soluble pillar[6]arene (WP6A) host and a sodium decanesulfonate guest (G) is reported. The chemotherapeutic agent doxorubicin hydrochloride (DOX) can be encapsulated into the formed vesicle (G/WP6A) to construct supramolecular DDS (DOX@G/WP6A). WP6A affords strong affinities to G to avoid undesirable off-target leakage during delivery. Nanoscaled DOX@G/WP6A is capable of preferentially accumulating in tumor tissue via enhanced permeability and retention (EPR) effect. After internalization by tumor cells, the abundant adenosine triphosphate (ATP) binds competitively with WP6A to trigger the disintegration of self-assembled vesicles with the ensuing release of DOX. In vitro and in vivo research confirmed that DOX@G/WP6A is not only able to promote antitumor efficacy but also reduce DOX-related systemic toxicity. The above favorable findings are ascribed to the formation of ternary self-assembly, which profits from the combination of the factors of the EPR effect and the ATP-triggered release.

Tuning Supramolecular Polymers' Amphiphilicity via Host-Guest Interfacial Recognition for Stabilizing Multiple Pickering Emulsions

Supramolecular host-guest chemistry bridging the adjustable amphiphilicity and macromolecular self-assembly is well advanced in aqueous media. However, the interfacial self-assembled behaviors have not been further exploited. Herein, we designed a β-cyclodextrin-grafted alginate/azobenzene-functionalized dodecyl (Alg-β-CD/AzoC12) supra-amphiphilic system that possessed tunable amphiphilicity by host-guest interfacial self-assembly. Especially, supra-amphiphilic aggregates could be utilized as highly efficient soft colloidal emulsifiers for stabilizing water-in-oil-water (W/O/W) Pickering emulsions due to the excellent interfacial activity. Meanwhile, the assembled particle structures could be modulated by adjusting the oil-water ratio, resulting from the tunable aggregation behavior of supra-amphiphilic macromolecules. Additionally, the interfacial adsorption films could be partially destroyed/reconstructed upon ultraviolet/visible irradiation due to the stimuli-altering balance of amphiphilicity of Alg-β-CD/AzoC12 polymers, further constructing the stimulus-responsive Pickering emulsions. Therefore, the supramolecular interfacial self-assembly-mediated approach not only technologically advances the continued development of creative templates to construct multifunctional soft materials with anisotropic structures but also serves as a creative bridge between supramolecular host-guest chemistry, colloidal interface science, and soft material technology.

Self-Assembly of a Pyridine-Based Amphiphile Complexed with Regioisomeric Dihydroxy Naphthalenes into Supramolecular Nanotubes with Different Inner Diameters

A pyridine-based amphiphile complexed with 1,5-, 1,6-, 2,6-, or 2,7-dihydroxy naphthalene self-assembled in water to form nanotubes with inner diameters of 46, 38, 24, 18, and 11 nm in which the naphthalene molecules formed J-type aggregates. In contrast, the amphiphile complexed with 1,2-, 1,3-, 1,4-, 1,7-, 1,8-, or 2,3-dihydroxy naphthalene formed nanofibers in which the naphthalene molecules formed H-type aggregates. The inner diameter of the nanotubes strongly depended on the regioisomeric dihydroxy naphthalene. UV-vis, fluorescence, infrared spectroscopy, X-ray diffraction analysis, and differential scanning calorimetry showed that nanotubes with smaller inner diameters had weaker intermolecular hydrogen bonds between the tilted amphiphiles complexed with the naphthalene molecules within the membrane walls and showed larger Stokes shifts in the excimer fluorescence of the naphthalene moiety. These findings should be useful not only for fine-tuning the inner diameters of supramolecular nanotubes but also for controlling the aggregation states of functional aromatic molecules to generate nanostructures with useful optical and electronic properties in water.

An antibody-like peptidic network for anti-angiogenesis

Different from chemical (small molecular inhibitor) and biological (monoclonal antibody) drugs, herein, based on angiogenesis-related neuropilin-1 (NRP-1), we develop a biomimetic superstructure drug, i.e. an antibody-like peptidic network (ALPN) to achieve the high-efficient treatment of choroidal neovascularization (CNV). The ALPN in nanoparticulated formulation (ALPN-NP_S) can bind NRP-1 through targeting unit and form fibrous peptidic networks trapping NRP-1 on the surface of endothelial cells (ECs), leading to anti-angiogenesis. The ALPN shows high-efficacy against angiogenesis in CNV rat model ascribed to the superstructure-enhanced binding and blockage of NRP-1. The very low dose of ALPN (0.263 μg/Kg) exhibits similar anti-angiogenesis effect comparing with monoclonal antibody bevacizumab (23.5 μg/Kg), which shows potential advantages over traditional monoclonal antibodies.

Force-Induced Self-Assembly of Supramolecular Modified Mica Nanosheets for Ductile and Heat-Resistant Mica Papers

Mica is a naturally abundant layered silicate mineral that has higher strength than other layered silicate minerals, but its inherent brittleness limits its application in some fields. In this work, mica was ultrasonically exfoliated into a single-layered nanomaterial after thermal activation, acidification, sodium replacement, and cetyltrimethylammonium bromide (CTAB) intercalation and then modified with ureido-pyrimidinone (UPy)-based PEG chains. Vacuum-assisted self-assembly was used to construct supramolecularly modified single-layered mica into bulk materials, in which the mica nanosheets were stacked into mica paper. The reversible quadruple hydrogen-bonded UPy moieties provided a high binding constant and significantly improved the strength and toughness of the obtained mica paper. These force-induced assembled mica papers showed significantly improved tensile strength and toughness compared with pure mica paper and simultaneously maintained the heat resistance of the mica materials, which may be good candidates for the substrates of flexible sensors working at higher temperatures.

Recent advances in supramolecular block copolymers for biomedical applications

Supramolecular block copolymers (SBCs) have received considerable interest in polymer chemistry, materials science, biomedical engineering and nanotechnology owing to their unique structural and functional advantages, such as low cytotoxicity, outstanding biodegradability, smart environmental responsiveness, and so forth. SBCs comprise two or more different homopolymer subunits linked by noncovalent bonds, and these polymers, in particular, combine the dynamically reversible nature of supramolecular polymers with the hierarchical microphase-separated structures of block polymers. A rapidly increasing number of publications on the synthesis and applications of SBCs have been reported in recent years; however, a systematic summary of the design, synthesis, properties and applications of SBCs has not been published. To this end, this review provides a brief overview of the recent advances in SBCs and describes the synthesis strategies, properties and functions, and their widespread applications in drug delivery, gene delivery, protein delivery, bioimaging and so on. In this review, we aim to elucidate the general concepts and structure-property relationships of SBCs, as well as their practical bioapplications, shedding further valuable insights into this emerging research field.

Polymeric Systems Containing Supramolecular Coordination Complexes for Drug Delivery

Cancer has become a common disease that seriously endangers human health and life. Up to now, the essential treatment method has been drug therapy, and drug delivery plays an important role in cancer therapy. To improve the efficiency of drug therapy, researchers are committed to improving drug delivery methods to enhance drug pharmacokinetics and cancer accumulation. Supramolecular coordination complexes (SCCs) with well-defined shapes and sizes are formed through the coordination between diverse functional organic ligands and metal ions, and they have emerged as potential components in drug delivery and cancer therapy. In particular, micelles or vesicles with the required biocompatibility and stability are synthesized using SCC-containing polymeric systems to develop novel carriers for drug delivery that possess combined properties and extended system tunability. In this study, the research status of SCC-containing polymeric systems as drug carriers and adjuvants for cancer treatment is reviewed, and a special focus is given to their design and preparation.

Building a quadruple stimuli-responsive supramolecular gel based on a supra-amphiphilic metallogelator

A supramolecular gel was fabricated based on a novel supra-amphiphilic metallogelator, and it showed quadruple stimuli-responsive properties.

Controllable and Diversiform Topological Morphologies of Self-Assembling Supra-Amphiphiles with Aggregation-Induced Emission Characteristics for Mimicking Light-Harvesting Antenna

Controllable construction of diversiform topological morphologies through supramolecular self-assembly on the basis of single building block is of vital importance, but still remains a big challenge. Herein, a bola-type supra-amphiphile, namely DAdDMA@2β-CD, is rationally designed and successfully prepared by typical host-guest binding β-cyclodextrin units with an aggregation-induced emission (AIE)-active scaffold DAdDMA. Self-assembling investigation reveals that several morphologies of self-assembled DAdDMA@2β-CD including leaf-like lamellar structure, nanoribbons, vesicles, nanofibers, helical nanofibers, and toroids, can be straightforwardly fabricated by simply manipulating the self-assembling solvent proportioning and/or temperature. To the best of knowledge, this presented protocol probably holds the most types of self-assembling morphology alterations using a single entity. Moreover, the developed leaf-like lamellar structure performs well in mimicking the light-harvesting antenna system by incorporating with a Förster resonance energy transfer acceptor, providing up to 94.2% of energy transfer efficiency.

In situ self-assembled biosupramolecular porphyrin nanofibers for enhancing photodynamic therapy in tumors

Due to the complicated environment and high tissue hydraulic pressure in tumors that easily pumps the nanomedicines back to the systemic circulation, the concentration of released photosensitizers (PSs) retained in a tumor by a traditional nano-delivery system is very low, causing an unsatisfactory photodynamic therapy (PDT) effect. Therefore, we prepared a pH/H₂O₂-responsive nano-system (ZnP-OC-M) through modified porphyrin PS units with a long-unsaturated oleoyl chloride chain, and by the further introduction of hydrophilic hydroxyl groups and MnO₂ through a cis-addition reaction between the unsaturated double bonds of oleoyl chloride and dilute KMnO₄ solution. Making use of the sensitivity of MnO₂ to the H₂O₂ in the acid environment of tumor cells, ZnP-OC-M selectively realized responsive disintegration and O₂ generation. More importantly, the rich amphiphilic PS units were shedded simultaneously and spontaneously completed the self-assembly into nanofibers in situ by helical stacking, which displayed a 1.85-fold higher retention effect of PSs in vivo compared with free PS groups and showed a great tumor inhibition effect in enhancing PDT. This nanosystem effectively solves the problem of the low retention abilities leading to a poor PS concentration in a tumor, prolonging the treatment time window efficiently after only a single administration and achieving the purpose of PDT enhancement.

Assembling Anthracene-Tailored Amphiphiles: Charge-Transfer Interactions Directed Hierarchical Nanofibers with Ameliorative Antibacterial Activity toward Plant Pathogens

The effective prevention of plant bacterial infections has been complicated and challenged by unceasing bacterial resistance. The application of traditional bactericides has achieved certain effects to alleviate this situation. However, these chemicals also have limitations, such as short half-life in reality, limited bioavailability, and pollutant emission from their formulations. These disadvantages drive the demand for promoting antibacterial therapeutics. Self-assembled nanostructures based on amphiphiles have inherently versatile characteristics, including high durability, good bioavailability, sustained release, and regenerability. As such, they have garnered wide interest because of these advantages that may serve as a feasible platform for the management of pathogenic infections. Flexible tuning of the shapes of these nanostructures by manipulating noncovalent driving forces consequently results in different levels of antibacterial activity. Herein, an antibacterial amphiphile, 1-[11-(9-anthracenylmethoxy)-11-oxoundecyl]pyridinium bromide (AP), was assembled into microfilms in screening medium. Hierarchical nanofibers were constructed by introducing an electron-deficient trinitrofluorenone (TNF) molecule into the assembling system directed by charge-transfer (CT) interactions to further investigate the contribution of aggregate shape to bioactivity. Biological evaluation revealed that antibacterial efficacy improved after CT complex formation. This study provides an innovative platform for developing versatile assembled structures for restraining the propagation of plant pathogens and an improved understanding of the actual interplay between the self-assembly and antibacterial ability of bactericides at the supramolecular level.

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

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.

Regulating the Structures of Self-Assembled Mechanically Interlocked Moleculecular Constructs via Dianion Precursor Substituent Effects

Substituent effects play critical roles in both modulating reaction chemistry and supramolecular self-assembly processes. Using substituted terephthalate dianions (p-phthalic acid dianions; PTADAs), the effect of varying the type, number, and position of the substituents was explored in terms of their ability to regulate the inherent anion complexation features of a tetracationic macrocycle, cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene) (referred to as the Texas-sized molecular box; 1⁴⁺), in the form of its tetrakis-PF₆^- salt in DMSO. Several of the tested substituents, including 2-OH, 2,5-di(OH), 2,5-di(NH₂), 2,5-di(Me), 2,5-di(Cl), 2,5-di(Br), and 2,5-di(I), were found to promote pseudorotaxane formation in contrast to what was seen for the parent PTADA system. Other derivatives of PTADA, including those with 2,3-di(OH), 2,6-di(OH), 2,5-di(OMe), 2,3,5,6-tetra(Cl), and 2,3,5,6-tetra(F) substituents, led only to so-called outside binding, where the anion interacts with 1⁴⁺ on the outside of the macrocyclic cavity. The differing binding modes produced by the choice of PTADA derivative were found to regulate further supramolecular self-assembly when the reaction components included additional metal cations (M). Depending on the specific choice of PTADA derivatives and metal cations (M = Co²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Gd³⁺, Nd³⁺, Eu³⁺, Sm³⁺, Tb³⁺), constructs involving one-dimensional polyrotaxanes, outside-type rotaxanated supramolecular organic frameworks (RSOFs), or two-dimensional metal-organic rotaxane frameworks (MORFs) could be stabilized. The presence and nature of the substituent were found to dictate which specific higher order self-assembled structure was obtained using a given cation. In the specific case of the 2,5-di(OH), 2,5-di(Cl), and 2,5-di(Br) PTADA derivatives and Eu³⁺, so-called MORFs with distinct fluorescence emission properties could be produced. The present work serves to illustrate how small changes in guest substitution patterns may be used to control structure well beyond the first interaction sphere.

Structurally Tunable pH-Responsive Luminescent Assemblies from Halogen Bonded Supra-π-amphiphiles

Supra-amphiphiles constituted of noncovalent bonds have emerged as attractive systems for fabrication of stimuli-responsive self-assembled nanostructures. A unique supramolecular strategy utilizing halogen (X)-bonding interaction has been demonstrated for constructing emissive supra-π-amphiphiles in water from a hydrophobic pyridyl functionalized naphthalene monoimide (NMI-Py) based X-bond acceptor and hydrophilic iodotetrafluorophenyl functionalized polyethylene glycol (PEG-I) or triethylene glycol (TEG-I) based X-bond donors, while their luminescent higher ordered assemblies were governed by orthogonal dipole-dipole interaction and π-stacking of the NMI-Py fluorophore as probed by SCXRD and DFT calculations. Control molecules lacking iodotetrafluorophenyl moiety at the polyethylene glycol chain end failed to create any defined morphology from the NMI-Py, suggesting X-bonding is prerequisite for the nanostructure formation. Variation in the chain length of the X-bond donors leads to different morphologies (fiber vs vesicle) for PEG-I and TEG-I. Acid triggered denaturing of the X-bonds caused pH responsive disassembly of the thermally robust nanostructures. This strategy paves the way for facile fabrication of structurally diverse smart and adaptive luminescent functional materials with tunable morphology.