Co-assembled white-light-emitting hydrogel of melamine

A temperature and pressure dual-responsive, stretchable, healable, adhesive, and biocompatible carboxymethyl cellulose-based conductive hydrogels for flexible wearable strain sensor

The study aimed to develop a novel temperature and pressure dual-responsive conductive hydrogel with self-healing, self-adhesive, biocompatible, and stretchable properties, for the development of multifunctional anti-counterfeiting and wearable flexible electronic materials. A conductive hydrogel based on carboxymethyl cellulose (CMC) was synthesized by simple "one pot" free radical polymerization of CMC, acrylamide (AAm) and acrylic acid (AAc). The hydrogel displayed temperature responsiveness and possessed an upper critical solution temperature (UCST) value. In addition, hydrogels also had surprising pressure responsiveness. The synthesized hydrogels were characterized by FTIR, TGA, DSC, and XRD analysis. Importantly, the obtained hydrogels exhibited exceptional mechanical properties (stress: 730 kPa, strain: 880%), fatigue resistance, stretchability, self-healing capability, self-adhesive properties, and conductivity. In addition, valuable insights were obtained into the synthesis and application of flexible anti-counterfeiting and camouflage materials by the temperature and pressure dual-responsive hydrogels. Moreover, the prepared hydrogel, with an electrically sensitive perception of external strain (GF = 2.61, response time: 80 ms), can be utilized for monitoring human movement, emotional changes, physiological signals, language, and more, rendering it suitable for novel flexible anti-counterfeiting materials and versatile wearable iontronics. Overall, this study provided novel insights into the simple and efficient synthesis and sustainable manufacturing of environmentally friendly multifunctional anti-counterfeiting materials and flexible electronic skin sensors.

Adenine selected hydrogelation of vitamin B2 with amplified circularly polarized luminescence

Although the individual VB2 cannot form gels in water, it could form a two-component hydrogel with adenine (A) through the intermolecular π-π stacking and hydrogen bonding between VB2 and A, while other nucleobases, including thymine (T), guanine (G), cytosine (C) and uracil (U), could not. The chiral information of VB2 was amplified in the co-assembly of VB2 and A, which was revealed by the enhanced circular dichroism (CD) and circularly polarized luminescence (CPL). Moreover, due to the different interaction modes between VB2 and A in 1 : 1 and 1 : 2 molar ratio, a reversion of the CPL signal was observed. This work demonstrated how biological molecules could be fabricated into functional materials using the specific interactions within the biological molecules.

Supramolecular polymers based on host-guest interactions for the construction of artificial light-harvesting systems

In the present work, artificial light-harvesting systems with a fluorescence resonance energy transfer (FRET) process were successfully obtained in the aqueous solution. We designed and synthesized an amphiphilic pyrene derivative with two 4-vinylpyridium arms (Pmvb), which can interact with cucurbit[8]uril (CB[8]) to form supramolecular polymer through host-guest interactions in aqueous solution. The formation of supramolecular polymers results in a significant enhancement of fluorescence, which makes Pmvb-CB[8] an ideal energy donor to construct artificial light-harvesting systems in the aqueous solution. Subsequently, two different fluorescence dyes Rhodamine B (RhB) and Sulforhodamine 101 (SR101) were introduced as energy acceptors into the solution of Pmvb-CB[8] respectively, to fabricate two different artificial light-harvesting systems. The obtained artificial light-harvesting systems can achieve an efficient energy transfer process from Pmvb-CB[8] to RhB or SR101 with high energy transfer efficiency.

Artificial Light-Harvesting System with White-Light Emission in a Bicontinuous Ionic Medium

Artificial light-harvesting systems (ALHSs), which are closely related to Förster resonance energy transfer (FRET), are among the most attractive scientific topics during the past few decades. Specifically, binary ALHSs that are composed of a fluid donor and acceptor have a simplified composition and high number density of the donor units. However, largely due to the difficulty in obtaining a fluid donor, investigation of these systems is still quite limited, especially for the ionic systems. Herein, we report a new type of binary ALHS using an ionic naphthalimide (NPI) derivative as a donor, which shows greatly improved photoluminescence for its bicontinuous liquid structure. When blending with an acceptor such as rhodamine 6G or trans-4-[4-(dimethylamino)styryl]-methylpyridinium iodide, efficient FRET was confirmed by both experimental results and molecular dynamics simulations, with an energy transfer efficiency up to ∼90%. Tunable color, including white-light emission, was achieved by tuning the acceptor/donor ratio, opening the door for a variety of applications such as light-emitting diodes and photoluminescent inks.

Recent Progress in Smart Polymeric Gel-Based Information Storage for Anti-Counterfeiting

Information security protection has a tremendous impact on human life, social stability and national security, leading to the rapid development of anti-counterfeiting materials and related techniques. However, the traditional stored information on hard or dry media is often static and lacks functions, which makes it challenging to deal with increasing and powerful counterfeiting technologies. Modified intelligent polymeric gels exhibit color changes and shape morphing under external stimuli, which give them great potential for applications in information storage. This paper provides an overview of the latest progress in polymeric gel-based information storage materials in relation to counterfeiting. Following a brief introduction of anti-counterfeiting materials, the preparation methods for intelligent gels with adjustable colors (e.g., chemical colors and physical colors) and various encryption/decryption modes involving dimensions and diverse colors are outlined. Finally, the challenges and prospects for information storage and anti-counterfeiting based on smart gels are discussed.

Single-Component White Light Emission from a Metal-Coordinated Cyclotriveratrylene-Based Coordination Polymer

A coordination polymer, namely, [Cd₃L(H₂O)₃]·DMA·4H₂O (1) (DMA = N,N-dimethylacetamide), was prepared by the solvothermal reaction of cyclotriveratrylene-based ligand 5,6,12,13,19,20-hexacarboxy-methoxy-cyclotriveratrylene (H₆L) and Cd(NO₃)₂·4H₂O. In 1, a two-dimensional structure was constructed by the connection of hexanuclear Cd-O clusters and L^6- anions. Photoluminescence measurements indicated that 1 displayed tunable photoluminescence through the variation of the excitation wavelength. Significantly, the white light emission of 1 can be observed with a broad excitation wavelength range from 320 to 385 nm. When 1 is excited by 385 nm light, its chromatic coordinate is (0.29, 0.34), which is located very close to the pure white light region (0.33, 0.33). Meanwhile, the color temperature (CCT) is 7994 K, which corresponds well to "cold" white light.

Phenothiazine and triphenylamine-based fluorescent Schiff bases for the dual application of white light generation and H2O2 sensing

Two simple Schiff bases applied for white light emission in an ionic liquid medium and peroxide sensing with an exceptional LOD.

Feasible polarised white-light emission based on conjugate plane-structured yellow/blue dye molecules encapsulated in metal-organic frameworks

We use a two-stage hierarchical growth method to encapsulate the blue KSN and yellow RhB molecules into a MOF crystal. By aligning these two conjugate plane-structured molecules in the MOF channel, a polarised white-light emission is obtained, with CIE coordinates of (0.3285, 0.3204) and a polarization ratio of 2.98.

Paintable Hybrids with Thermally Stable Dual Emission Composed of Tetraphenylethene-Integrated POSS and MEH-PPV for Heat-Resistant White-Light Luminophores

Thermally stable dual emission followed by white-light luminescence from hybrid materials is reported. Hybrid films were prepared with a spin-coating method with the mixture solution containing tetraphenylethene (TPE)-integrated polyhedral oligomeric silsesquioxane (POSS) and poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV). TPE-tethered POSS (TPE-POSS) showed high compatibility with MEH-PPV. Therefore, homogeneous films with variable concentrations of TPE-POSS were obtained. Owing to good dispersion of rigid silica cubes into matrices, POSS-containing films demonstrated high thermal stability toward molecular rearrangement by annealing as well as pyrolysis, similar to conventional polymer hybrids. Furthermore, it was found that TPE-POSS was able to enhance emission efficiencies, probably by suppressing chain aggregation. By modulating introduction ratios of TPE-POSS, dual-emission properties followed by white-light luminescence composed of cyan and orange emissions from TPE-POSS and MEH-PPV, respectively, were accomplished. It should be noted that these color balances can be preserved even in the high-temperature region (425 K). Finally, white-light luminescent materials with thermal durability were obtained.

A robust stimuli responsive Eu3+ - Metalo organic hydrogel and xerogel emitting white light

Recently, there is incredible growth on optoelectronic properties of new supramolecular gels and white-light-emitting (WLE) metalo-organic gel comprised with single lanthanide metal ion having stimuli-responsive property is not yet reported. Here, we report a mandelic acid (MA)-triethylene tetraamine (TETA)-Eu-acetate conjugate (4.5:1:0.4 mol ratio), producing stimuli-sensitive WLE hydrogel exhibiting thermoreversible, thixotropic, pH-switchable, self-standing and self-healing properties. Energy minimized structure suggests complexation between MA-TETA conjugate and Eu³⁺ ion. Fluorescence intensity of MA-TETA conjugate decreases with increasing Eu³⁺ concentration indicating energy transfer from MA-TETA to Eu³⁺. Decay of donor fluorescence intensity follows Stern-Volmer equation and energy transfer efficiency is 42%. WLE gel has Quantum yield 11.4% and Förster distance 1.7 Å. Hydrogel and xerogel show WLE on excitation at 330 and 350 nm having CIE coordinates (0.34, 0.33) and (0.28, 0.32), respectively. WLE gel has Correlated colour temperature 5148 K, appropriate for cool day light emission and on coating over UV-LED bulb it emits bright white light.

White-light-emitting hydrogels with self-healing properties and adjustable emission colors

White-light-emitting soft materials with self-healing properties show extensive applications in many fields. Herein, a novel self-healing hydrogel is successfully fabricated using oxidized dextran (Odex) and dithiodipropionate dihydrazide (TPH). Carbon dots (CDs), Riboflavin (Ri) and Rhodamine B (RhB) are incorporated into the gel matrix to produce white light emission through fluorescence resonance energy transfer (FRET) process, thus achieving excellent Commission Internationale de L'eclairage (CIE) coordinate value of (0.30, 0.33). The emission colors can be easily tuned via changing proportions of three emitters or the excitation wavelength. When the hydrogels are coated on an ultraviolet light-emitting diodes (UV LED), the hydrogel coating converts UV light to white light and repairs itself in 20 h while a hole is dug from it. Thanks to reversible exchanging reactions of acylhydrazone and disulfide bonds in hydrogel networks, the hydrogel coating exhibits perfect self-healing property in a wide range of pH (from 5 to 9 except for 7). The excellent emission and self-healing properties of hydrogels have great value in practical applications.

Highly efficient full-color and white circularly polarized luminescent nanoassemblies and their performance in light emitting devices

Chiral nanomaterials with circularly polarized luminescence (CPL) have attracted increasing attention as they show improved luminous efficiency and high contrast images in optical displays. Herein, nanotwisted fibers with bright full-color CPL are developed through the co-assembly of chiral phenylalanine derived gelators and achiral aromatic molecules. The synergic effect of π-π stacking and hydrogen bonding interactions between the chiral and achiral building blocks results in long-range ordered self-assembly, enabling the chirality of the gelators to be better transmitted to the achiral aromatic molecules. Highly ordered co-assemblies lead to the formation of supramolecular gels with high glum values which range up to 10-3. Moreover, nanoassemblies with white CPL are obtained by tuning the ratio of colorful achiral aromatic molecules in the gels. These nanotwisted gels show diverse colors or even white circularly polarized light when coated on UV chips, which enable their future application in the construction of low-cost and flexible light-emitting devices such as circularly polarized organic light-emitting diodes (CPOLEDs).

Supramolecular Assembly-Driven Color-Tuning and White-Light Emission Based on Crown-Ether-Functionalized Dihydrophenazine

The development of color-tunable white-light-emitting systems is significant for artificial smart materials. Recently, a set of conformational dependent fluorophores N,N'-diaryl-dihydrodibenzo[a,c]phenazines (DPACs) have been developed with unique photoluminescence mechanism vibration-induced emission (VIE). DPACs can emit intrinsical blue emission at a bent excited state and abnormal orange-red emission at a planar excited state, which are due to the varied π-conjugation via excited-state configuration transformation along the N-N' axis from bent to planar form. Herein, a novel VIE-active compound DPAC-[B15C5]₂ is designed and synthesized with two wings of benzo-15-crown-5. The excited-state vibration of the DPAC moiety can be modulated by tuning the supramolecular assembly and disassembly via chelation competition of K⁺ between 15-crown-5 and 18-crown-6, and hence, a wide-color-tuning emission is achieved from blue to orange-red including white. Dynamic light scattering and transmission electron microscopy experiments were conducted to exhibit the supramolecular assembling process. Additionally, the moisture detection in organic solvents is realized since the water could dissociate the supramolecular assembly.

Tunable multi-color luminescence from a self-assembled cyanostilbene and cucurbit[7]uril in aqueous media

A tunable multicolor luminescent supramolecular system was designed in aqueous media employing the self-assembly of a cationic amphiphilic cyanostilbene and the host–guest chemistry of cucurbit[7]uril.

Terpyridine-functionalized chemically cross-linked polyacrylamide hydrogel for white emission and multistimuli-responsive behaviour

A highly efficient and multifunctional white-emitting hydrogel was fabricated using a facile copolymerization process by introducing a hydrophilic terpyridine-based chromophore into a polyacrylamide network.

Rotaxane-Based Mechanophores Enable Polymers with Mechanically Switchable White Photoluminescence

Three mechanoresponsive polyurethane elastomers whose blue, green, and orange photoluminescence can be reversibly turned on by mechanical force were prepared and combined to create a blend that exhibits deformation-induced white photoluminescence. The three polyurethanes contain rotaxane-based supramolecular mechanoluminophores based on π-extended pyrene, anthracene, or 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) luminophores, respectively, and 1,4,5,8-naphthalenetetracarboxylic diimide as an electronically matched quencher. Each polymer shows instantly reversible, strain-dependent switching of its photoluminescence intensity when stretched and relaxed, as deformation leads to a spatial separation of the luminophore and quencher. The present study shows that the photoluminescence color can easily be tailored by variation of the luminophore and also by combining several mechanophores in one material and demonstrates that adaptability is a key advantage of supramolecular approaches to create mechanoresponsive polymers.

Multitasking behaviour of a small organic compound: solid state bright white-light emission, mechanochromism and ratiometric sensing of Al(iii) and pyrophosphate

Solid state bright white-light emission, mechanochromism and ratiometric fluorescence sensing of Al³⁺ and pyrophosphate by a single organic molecule are demonstrated.

Single Chromophore-Based White-Light-Emitting Hydrogel with Tunable Fluorescence and Patternability

Bioluminescence is widespread in nature such as the jellyfish, which inspires scientists to design polymer hydrogels with tunable fluorescence. However, it remains a big challenge to develop white-light-emitting hydrogels with local tunability of the fluorescent behavior. Herein, we report a white fluorescent hydrogel prepared by one-pot micellar copolymerization of hydrophilic acrylamide and hydrophobic single donor-acceptor chromophore monomer, in which the unimer and the dimer of the chromophore coexist and generate high- and low-energy emission, respectively, under excitation. The fluorescent behavior of the hydrogel can be well tuned by phototreatment or heat treatment that induces unimer-to-dimer transformation of the chromophore and thus variation of the fluorescent color from blue to white and then to yellow. The fluorescence can also be reversibly switched off by forming terpyridine-Cu²⁺ chelate complexes and recovered by using chelating agent to extract the Cu²⁺ ions out of the gel matrix. These properties afford patterning the fluorescent hydrogel, which is transparent under daylight yet shows the pattern under ultraviolet light. These patterned fluorescent hydrogels should find applications in protected message display for improved information security.

Dual fluorescence of tetraphenylethylene-substituted pyrenes with aggregation-induced emission characteristics for white-light emission

This article presents a new strategy to achieve white-light emission from single tetraphenylethylene-substituted pyrenes (TPE-Pys) with aggregation-induced emission (AIE) characteristics. TPE-Pys were synthesized by a Pd-catalyzed coupling reaction of a boronic acid or pinacol ester of pyrene and tetraphenylethylene (TPE) derivatives and showed multicolor emission by introducing different substituents on the phenyl rings of TPE. TPE-Pys with a TPE unit at the 1-position and asymmetric TPE units at 2,7-positions show dual fluorescence in THF/water mixtures to realize white-light emission with CIE coordinates of (x = 0.30 and y = 0.41) and (x = 0.21 and y = 0.16), respectively. The structure-property relationship of TPE-Pys were investigated to elucidate the origin of the white emission. The results showed that due to the weak electronic interaction of pyrene and its chromophoric units at the 2,7-positions and the constraint of the rotation of the TPE unit at the 1-position of pyrene, each component can exhibit its own emission color. The combination of appropriate colors gives rise to white-light emission. Such a principle of molecular design may open a new avenue for preparing advanced multicolor and multifunctional optical materials for organic electronics.

White Light-Emitting Multistimuli-Responsive Hydrogels with Lanthanides and Carbon Dots

Polymers that confer changes in optical properties in response to chemical or mechanical cues offer diverse sensing applications, particularly if this stimuli response is accessible in humid or aqueous environments. In this study, luminescent hydrogels were fabricated using a facile aqueous process by incorporating lanthanide ions and carbon dots (CD) into a network of polyacrylamide and poly(acrylic acid). White luminescence was obtained by tuning the balance of blue-light-emitting CD to green- and red-light-emitting lanthanide ions. Exploiting the combined specific sensitivities of the different emitters, the luminescent hydrogel showed chromic responsiveness to multiple stimuli, including pH, organic vapors, transition-metal ions, and temperature. The white-light-emitting hydrogel was also stretchable with a fracture strain of 400%. We envision this photoluminescent hydrogel to be a versatile and multifunctional material for chemical and environmental sensing.

Tunable multicolor emissions in a monocomponent gel system by varying the solvent, temperature and fluoride anion

The facile tuning of the fluorescent properties of organogels is highly desirable for optical switches, light-emitting diodes, chemosensors and bioprobes. The design of organic molecules with multiple emission colors but only one molecular platform remains challenging. Herein, a new cholesterol-based organogelator N1 containing D-A pairs (salicylaldehyde and naphthalimide units) was designed. We successfully obtained multiple solvent-tuned emission colors in both the solution and gel states using a unimolecular platform. Moreover, the effects of the solvent on the gel morphology, rheology and anion-responsive properties were studied. Finally, we showed that the gel in benzene displayed reversible thermochromic properties with changes in emission color from yellow-green to red. Several experiments suggested that a short-distance and ordered array of the D-A pairs facilitated the efficient intermolecular electron transfer of the fluorophores.

Facile synthesis of triphenylamine and phenothiazine-based Schiff bases for aggregation-induced enhanced emission, white light generation, and highly selective and sensitive copper(ii) sensing

Facile synthesis of triphenylamine and phenothiazine based Schiff bases for multiple applicability, viz., in AIEE, WLE and Cu²⁺ sensing.

White light emission from fluorene-EDOT and phenothiazine-hydroquinone based D–π–A conjugated systems in solution, gel and film forms

The appropriate composition of two new D–π–A conjugated organic molecules in combination with rhodamine B is observed to emit cool white light in solution and solid states.

Broad-Spectrum Tunable Photoluminescent Nanomaterials Constructed from a Modular Light-Harvesting Platform Based on Macrocyclic Amphiphiles

Broad-spectrum tunable photoluminescent nanomaterials are developed based on macrocyclic amphiphiles serving as a novel modular light-harvesting platform with discrete addressability of luminophores in a noncovalent way. By simply varying the donor/acceptor ratio, a broad spectrum of energy transfer outputs is achieved, pointing toward a proof-of-principle application as fluorescent inks for security printing.

Lamellar Peptide-Cadmium-Doped Zinc Oxide Nanohybrids That Emit White Light

A variety of hybrid nanostructures have been developed that emit white light. Two different white-light-emitting systems are reported. These are cadmium-doped zinc oxide nanosheets and complex lamellar nanostructures that consist of alternating inorganic cadmium-doped zinc oxide domains with the self-assembled aromatic-capped peptide BPI-FF-OH (BPI: benzo[ghi]perylene monoimide, F: d-phenylalanine). An electrochemical method is employed to synthesize cadmium-doped zinc oxide nanosheets and lamellar organic/cadmium-doped zinc oxide nanoflakes on a gallium-doped ZnO/p-Si (111) substrate. External structural features and internal structural ordering of wurtzite cadmium-doped zinc oxide and lamellar organic/cadmium-doped zinc oxide nanohybrids are characterized by small-angle X-ray scattering, XRD, field-emission SEM, energy-dispersive X-ray spectroscopy, secondary-ion mass spectrometry, ellipsometry, and photoluminescence spectroscopy. Cadmium-doped zinc oxide nanosheets and lamellar organic/cadmium-doped zinc oxide hybrids emit white light with a broad emission covering the visible spectrum from λ=415 to 700 nm. Characteristic white-light emissions of both materials were well characterized by photoluminescence studies. The white-light luminescence is attributed to cadmium doping in the zinc oxide crystal and the presence of the dipeptide-functionalized BPI fluorophore in the lamellar nanohybrid.

Pure white light emission from organic molecules using solvent induced selective self-assembly

Selectively promoting and preventing aggregation of structurally similar anthracene derivatives to obtain pure white light emission.

Two in one: switchable ion conductivity and white light emission integrated in an iodoplumbate-based twin chain hybrid crystal

A [Pb₂I₆]_∝ twin chain hybrid crystal shows novel switchable ion conductivity arising from the structural phase transition and color-tunable photoluminescence attributed to the broadband semiconductor emission of twin chain.

White light emissive molecular siblings

White-light emission from boron based molecular siblings.

Supramolecular Hydrogelators and Hydrogels: From Soft Matter to Molecular Biomaterials

In this review we intend to provide a relatively comprehensive summary of the work of supramolecular hydrogelators after 2004 and to put emphasis particularly on the applications of supramolecular hydrogels/hydrogelators as molecular biomaterials. After a brief introduction of methods for generating supramolecular hydrogels, we discuss supramolecular hydrogelators on the basis of their categories, such as small organic molecules, coordination complexes, peptides, nucleobases, and saccharides. Following molecular design, we focus on various potential applications of supramolecular hydrogels as molecular biomaterials, classified by their applications in cell cultures, tissue engineering, cell behavior, imaging, and unique applications of hydrogelators. Particularly, we discuss the applications of supramolecular hydrogelators after they form supramolecular assemblies but prior to reaching the critical gelation concentration because this subject is less explored but may hold equally great promise for helping address fundamental questions about the mechanisms or the consequences of the self-assembly of molecules, including low molecular weight ones. Finally, we provide a perspective on supramolecular hydrogelators. We hope that this review will serve as an updated introduction and reference for researchers who are interested in exploring supramolecular hydrogelators as molecular biomaterials for addressing the societal needs at various frontiers.

Tunable and Switchable Control of Luminescence through Multiple Physical Stimulations in Aggregation-Based Monocomponent Systems

This report describes how the luminescence of naphthalimide could be tuned by various physical stimuli, including heat, sonication, and grinding. Herein, instant and switchable control of color and fluorescent emissions has been achieved by the sonication-triggered gelation of an organic liquid with naphthalimide-based organogelators (N3-N7). Green emissive suspensions of the gelators in organic liquids are transformed into orange emissive gels upon brief irradiation with ultrasound with an emission wavelength red-shift of approximately 60 nm and fluorescence intensity quenching by a factor of 20, which can subsequently be reversed by heating. When sonication-triggered S-gels are evaporated to S-xerogels, the solid state xerogels (N3, N4, N6, N7) exhibit mechanochromism, the color of which changes from red to yellow and the emission color of which changes from orange to green with enhanced intensity by grinding. This mechanochromic property can be reversed through a regelation process. The mechanochromic character of the S-xerogel of N3 is thus applied to quantitatively sense the mechanical pressure range from 2 to 40 MPa through fluorescence changes, reflecting a new type of application for gelation assembly. The physical stimuli triggered fluorescence changes of these compounds strongly depend on the molecular structure and solvent. The results demonstrate that the different aggregation modes and long-range order arrangement of the molecules regulated by the stimulus may affect the internal charge transfer (ICT) process of the naphthalimide groups, resulting in the tunability of the photophysical properties of the gelators. This report provides a new strategy for tunable and switchable control of luminescence through nonchemical stimuli in aggregation-based monocomponent systems.

White-Light-Emitting Lanthanide Metallogels with Tunable Luminescence and Reversible Stimuli-Responsive Properties

We have developed model light-emitting metallogels functionalized with lanthanide metal-ligand coordination complexes via a terpyridyl-end-capped four-arm poly(ethylene glycol) polymer. The optical properties of these highly luminescent polymer networks are readily modulated over a wide spectrum, including white-light emission, simply by tuning of the lanthanide metal ion stoichiometry. Furthermore, the dynamic nature of the Ln-N coordination bonding leads to a broad variety of reversible stimuli-responsive properties (mechano-, vapo-, thermo-, and chemochromism) of both sol-gel systems and solid thin films. The versatile functional performance combined with the ease of assembly suggests that this lanthanide coordination polymer design approach offers a robust pathway for future engineering of multi-stimuli-responsive polymer materials.

Artificial Peroxidase/Oxidase Multiple Enzyme System Based on Supramolecular Hydrogel and Its Application as a Biocatalyst for Cascade Reactions

Inspired by delicate structures and multiple functions of natural multiple enzyme architectures such as peroxisomes, we constructed an artificial multiple enzyme system by coencapsulation of glucose oxidases (GOx) and artificial peroxidases in a supramolecular hydrogel. The artificial peroxidase was a functional complex micelle, which was prepared by the self-assembly of diblock copolymer and hemin. Compared with catalase or horseradish peroxidase (HRP), the functional micelle exhibited comparable activity and better stability, which provided more advantages in constructing a multienzyme with a proper oxidase. The hydrogel containing the two catalytic centers was further used as a catalyst for green oxidation of glucose, which was a typical cascade reaction. Glucose was oxidized by oxygen (O2) via the GOx-mediated reaction, producing toxic intermediate hydrogen peroxide (H2O2). The produced H2O2 further oxidized peroxidase substrates catalyzed by hemin-micelles. By regulating the diffusion modes of the enzymes and substrates, the artificial multienzyme based on hydrogel could successfully activate the cascade reaction, which the soluble enzyme mixture could not achieve. The hydrogel, just like a protective covering, protected oxidases and micelles from inactivation via toxic intermediates and environmental changes. The artificial multienzyme could efficiently achieve the oxidation task along with effectively eliminating the toxic intermediates. In this way, this system possesses great potentials for glucose detection and green oxidation of a series of substrates related to biological processes.

Ultrasensitive ROS-Responsive Coassemblies of Tellurium-Containing Molecules and Phospholipids

Reactive oxygen species (ROS) play crucial roles in cell signaling and redox homeostasis and are strongly related to metabolic activities. The increase of the ROS concentration in organisms can result in several diseases, such as cardiovascular diseases and cancer. The concentration of ROS in biologically relevant conditions is typically as low as around tens of micromolars to 100 μM H2O2, which makes it necessary to develop ultrasensitive ROS-responsive systems. A general approach is reported here to fabricate an ultrasensitive ROS-responsive system via coassembly between tellurium-containing molecules and phospholipids, combining the ROS-responsiveness of tellurium and the biocompatibility of phospholipids. By using dynamic light scattering, transmission electron microscopy, scanning electron microscopy, and NMR spectra, coassembly behaviors and the responsiveness of the coassemblies have been investigated. These coassemblies can respond to 100 μM H2O2, which is a biologically relevant ROS concentration, and demonstrate reversible redox properties.

Supramolecular hydrogels: synthesis, properties and their biomedical applications

As a novel class of three-dimensional (3D) hydrophilic cross-linked polymers, supramolecular hydrogels not only display unique physicochemical properties (e.g., water-retention ability, drug loading capacity, biodegradability and biocompatibility, biostability) as well as specific functionalities (e.g., optoelectronic properties, bioactivity, self-healing ability, shape memory ability), but also have the capability to undergo reversible gel-sol transition in response to various environmental stimuli inherent to the noncovalent cross-linkages, thereby showing great potential as promising biomaterial scaffolds for diagnosis and therapy. In this Review, we summarized the recent progress in the design and synthesis of supramolecular hydrogels through specific, directional noncovalent interactions, with particular emphasis on the structure-property relationship, as well as their wide-ranging applications in disease diagnosis and therapy including bioimaging, biodetection, therapeutic delivery, and tissue engineering. We believe that these current achievements in supramolecular hydrogels will greatly stimulate new ideas and inspire persistent efforts in this hot topic area in future.

White light emission from a two-component hybrid gel via an energy transfer process

A two-component light-harvesting organogel containing a naphthalimide-based gelator as a donor and a phosphorescent Ir(iii) complex as an acceptor was used to produce white-light-emitting organogels.

Long-chain alkylamide-derived oil gels: mixing induced onset of thixotropy and application in sustained drug release

Oil gels composed of long-chain alkylamides exhibited thixotropic properties, although the same property was absent in each alkylamide.

Thermo-responsive white-light emission based on tetraphenylethylene- and rhodamine B-containing boronate nanoparticles

White-light emissive boronate nanoparticles have been prepared, which exhibit reversible and thermo-responsive emission in the investigated temperature range (5–65 °C) with a temperature sensitivity of 1.1% K⁻¹ in water.

Tuning of multiple luminescence outputs and white-light emission from a single gelator molecule through an ESIPT coupled AIEE process

A single gelator molecule (1) shows an ESIPT coupled AIEE process for generating multiple luminescent colors, including white-light, with varying aggregation as a function of the water content in a THF–water mixture. Luminescent property of 1 is retained in gel as well as in solid state.