AIE Materials Research Articles

Flexible AIE/PCM composite fiber with biosensing of alcohol, fluorescent anti-counterfeiting and body thermal management functions

Alcohol sensing plays a critical role in medical detection and personal health management. AIE materials with high sensitivity, selectivity and fast response have been widely used in biosensing, but their application in the field of alcohol sensing still needs further research and development. Furthermore, developing flexible phase change materials (PCMs) is significant for the research of human-body thermal management. In this study, a kind of flexible polyacrylonitrile (PAN)/polyvinylpyrrolidone (PVP)/polyethylene glycol (PEG)/Py-CH (pyrene-based AIE molecule)/SiO2@h-BN composite fiber textile (PAB) with alcohol sensing performance, writable fluorescence property, and human body thermal management function has been prepared via electrospinning technique. The PAN/PVP fiber matrix successfully integrated AIE fluorescent sensing material and PCM into a multi-functional composite with great shape stability. Owing to the introduction of novel pyrene-based Py-CH with AIE characteristic, this innovative textile exhibited wonderful fluorescent properties, including sensitive alcohol fluorescence sensing, writable fluorescence performance and variable temperature fluorescence. Furthermore, proposed PAB textile delivered a high energy storage density of 87∼90 J/g, excellent thermal reliability, great comprehensive mechanical flexibility and enhanced thermal conductivity for flexible human body thermal management. Hence, this flexible multifunctional AIE/PCM composite sensing textiles can be widely used in alcohol sensing, fluorescence anti-counterfeiting and flexible body thermal management.

A universal strategy for constructing high-performance silica-based AIE materials for biomedical application

As an emerging fluorophore, aggregation-induced emission luminogens (AIEgens) have received widespread attention in recent years, but the inherent drawbacks of AIEgens, such as the poor water-solubility and insufficient fluorescence stability in complex environments, restrict their performance in practical applications. Herein, we report a universal strategy based on hydrophobic dendritic mesoporous silica (HMSN) that can integrate different AIE molecules to construct multi-color fluorescent AIE materials. Specifically, HMSN with central radial pores was used as a powerful carrier for direct loading AIE molecules and restricting their intramolecular motions. Due to the pore-domain restriction effect and hydrophobic interaction, the obtained silica-based AIE materials have bright fluorescence with a maximum quantum yield of 68.38%, high colloidal/fluorescence stability, and excellent biosafety. Further, these silica-based AIE materials can be conjugated with functional antibodies to obtain probes with different targetability. After integration with immunomagnetic beads, the prepared detection probes achieved the quantitative detection of cardiac troponin I with the limit of detection (LOD) of 0.508 ng/mL. Overall, the targeting probes stemming from silica-based AIE materials can not only achieve cell-specific imaging, but quantify the number of Jurkat cells (LOD = 270 cells/mL) to further determine the specific etiology of the disease.

Metal–organic frameworks with aggregation‐induced emission

AbstractAggregation‐induced emission (AIE) materials exhibit remarkable emission in the aggregated or solid state while demonstrating minimal emission in dilute solutions. In contrast to conventional luminescent materials, AIE luminogens (AIEgens) offer several advantages in the aggregate state, including high quantum yield, excellent photostability, and low background signals, making them highly promising for diverse applications. Integrating AIEgens into designable metal–organic frameworks (MOFs) enables tunable and well‐ordered AIE materials, allowing for precise control over photophysical properties and deeper exploration of AIE mechanisms. Numerous AIE MOFs have been constructed and investigated, and several reviews focus on their structure design and applications in sensing and bioimaging. This review highlights the state‐of‐the‐art advancements in AIE MOFs, including mechanisms, design strategies, and applications in chemical sensing, bioimaging, and disease therapy. The challenges associated with practical applications of AIE MOFs are also addressed, with an emphasis on their large‐scale production involved interdisciplinary collaboration. This comprehensive review aims at guiding further development of AIE MOFs and promoting their practical applications in analysis, healthcare, and other luminescence related fields.

AIE Characteristics of Closely Packed Benzylidene Dimethylbarbituric Acid Derivatives

AbstractUsually, solid‐state fluorescence quenching is thought to be caused by π–π interaction. Hence, the common design strategies for materials with high‐brightness solid‐state luminescent rely on incorporating molecular rotors to weaken the intermolecular π–π packing. In this work, four types of BAs with the performance of solid‐state fluorescence and without molecular rotors have been synthesized. Among them, B‐4 was found to be a typical AIE compound and had a close cofacial packing mode, while it emitted strongly fluorescence in the solid state. The AIE characteristics of B‐4 was attributed to more electron‐donating groups and extended π‐conjugation. However, the other three BAs showed almost no fluorescence emission due to their more closed face‐to‐face packing mode or less electron‐donating groups. These results indicated that tight stacking mode unnecessarily lead to fluorescence quenching. This study suggests there may be fewer constraints to develop new AIE materials, and there might be a large number of tightly packed AIE molecules.

High-efficiency and low-efficiency roll-off fluorescence/phosphorescence hybrid white organic light-emitting diodes based on AIEgens with hot exciton property by strategically managing triplet excitons

OLEDs with efficient blue emission are fabricated using AIE materials. Utilizing TPB-AC enables high-efficiency two-color white OLEDs, and introducing a TTF layer significantly enhances the efficiency, the maximum efficiency increased to 23.2%.

Facile single-step synthesis of pentaaryl-substituted pyrano[3,2-b]pyrrol-5(1H)-ones showing aggregation-induced emission

The continuing desire for multifunctional AIE materials has stimulated intensified research efforts to develop both innovative synthetic techniques and novel scaffolds. Herein, we reported a new class of heterocyclic AIEgens,...

Lighting Up Fluorescence: Precise Recognition of Halogenated Solvents Through Effective Fluorescence Detection Using Chalcone Derivatives as a D-A-D-A-type Fluorescent Chemosensor.

In this paper, we report a D-A-D-A-type fluorescence sensor, FX, composed of triphenylamine and pyrazine units as electron donors, pyridine units, and α-β unsaturated carbon-based structures as electron acceptors. FX exhibits typical ICT characteristics. As a dual-emission material, FX undergoes acid-base-induced color changes and displays mechanofluorochromic properties in the solid state. In solution, FX, as an AIE material, shows significant fluorescence enhancement behavior in most halogenated solvents. Notably, it achieves a high quantum yield of 0.672 in a chloroform solution. We utilized this phenomenon to quantitatively detect chloroform through fluorescence titration analysis, with a detection limit of 0.061%. Additionally, we developed a test paper to verify the practical applicability of the sensor for detecting halogenated solvents. The fluorescence enhancement behavior was confirmed through DFT calculations. The results indicate that FX is not only a multifunctional dual-state emission material but also provides valuable references for the fluorescence detection of halogenated solvents.

Charge Separation to Facilitate The Conversion of Copper‐Phenylacetylide from Aggregation‐Induced Emission to Efficient Photocatalysis

AbstractAggregation‐induced emission (AIE) materials are considered promising photocatalyst candidates due to their robust light‐harvesting and efficient photoexcitation, if their photoexcited carriers can be separated effectively. Herein, by skillfully selecting multi‐alkynyl ligands instead of phenylacetylene to construct multi‐channel charge separation, copper‐phenylacetylide (CP‐1) with AIE properties is successfully transformed into efficient photocatalysts CP‐2P (copper‐1,4‐diethynylbenzene) and CP‐2M (copper‐1,3‐diethylnylbenzene). In these structures, the multi‐alkynyl ligands connects the copper‐ladder into multi‐dimensional metal‐organic frameworks with greatly reduced bandgap, enhances charge transfer and separation, and facilitated oxygen adsorption and activation. As a representative, CP‐2P has the best photocatalytic activity and stability for photocatalytic aerobic oxidation, such as thioanisole oxidation (conv. > 99%, methyl phenyl sulfoxide sel. ≧ 94%), benzyl alcohol oxidation (conv. > 99%, benzaldehyde sel. > 99%) and benzylamine oxidation (conv. > 99%, N‐benzylidene benzylamine sel. > 99%), which can be used for large‐scale sunlight‐driven organic photosynthesis. This work confirms the feasibility of controlled conversion of the conventional copper‐alkynyl from AIE material to efficient photocatalyst using charge separation strategy, which provides an important guidance for the rational design of new high‐efficiency photocatalyst.

Effects of Plasticizers on Structural Transitions and Heterogeneity of Poly(vinyl alcohol) Films as Studied via AIE Materials

Effects of Plasticizers on Structural Transitions and Heterogeneity of Poly(vinyl alcohol) Films as Studied via AIE Materials

Aggregation‐induced emission polymers via reversible‐deactivation radical polymerization

AbstractAggregation‐induced emission (AIE) is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation‐caused quenching (ACQ). AIE has the potential to be utilized in the large‐scale production of AIE‐active polymeric materials because of their wide range of practical applications such as stimuli‐responsive sensors, biological imaging agents, and drug delivery systems. This is evident from the increasing number of publications over the years since AIE was first discovered. In addition, the ever‐growing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers, initiators and crosslinkers, with the goal of broadening the scope and utility of AIE polymers. One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible‐deactivation radical polymerization (RDRP) techniques, which enabled the production of well‐controlled AIE materials that are often difficult to achieve by other methods. In this review, a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented, including (i) the design of AIE‐related monomers, initiators/crosslinkers; the achievements in preparation of AIE polymers using (ii) reversible addition–fragmentation chain transfer (RAFT) technique; (iii) atom transfer radical polymerization (ATRP) technique; (iv) other techniques such as Cu(0)‐RDRP technique and nitroxide‐mediated polymerization (NMP) technique; (v) the possible applications of these AIE polymers, and finally (vi) a summary/perspective and the future direction of AIE polymers.

Inorganic‐Based Aggregation‐Induced Luminescent Materials: Recent Advances and Perspectives

Luminogens with aggregation‐induced emission properties (AIEgens), as a novel and attractive fluorescent molecule, have been used in various fields, such as detection, imaging, and disease treatment, which can overcome the traditional aggregation‐caused quenching of organic fluorescent molecules. Nevertheless, AIEgens still have the problems of water solubility and fluorescence stability in practical applications. Aiming for improving the AIEgens’ performance and promoting the development of diverse applications of AIEgens, it is an available strategy to bind AIEgens to those inorganic materials with abundant variety, easy synthesis, and a unique rigid pore structure. The constructed inorganic‐based AIE materials not only inherit the unique luminescence characteristics of AIEgens, but also retain the biocompatibility and degradability of inorganic materials, endowing AIEgens with more attractive versatility. Herein, the up‐to‐date researches of several representative inorganic‐based AIE materials are introduced, with emphasis on their structure design, synthesis strategy, regulation of fluorescence properties of AIE, and their application in the biological field. Finally, the current situation, challenges, and future development potential of inorganic‐based AIE materials are discussed and prospected.

Target-Induced AIE Effect Coupled with CRISPR/Cas12a System Dual-Signal Biosensing for the Ultrasensitive Detection of Gliotoxin.

Here, a novel rapid and ultrasensitive aptamer biosensor was designed for target-induced activation of AIE effect and followed by the activation of Crispr Cas12a (LbCpf1)-mediated cleavage to achieve dual-signal detection. The prepared DNA building blocks contain the target aptamer, ssDNA-Fc, and Activator1. In this system, the activation mode was divided into two steps. First, when the target interacts with the aptamers, the DNA building blocks would be disintegrated rapidly, releasing a mass of Ac1, generating ETTC-dsDNA aggregated to produce a fluorescence signal by the AIE effect. Second, with the release of Ac2, LbCpf1-crRNA was activated, which greatly improves the ssDNA-Fc cleavage efficiency to render signal amplification and ultrasensitive detection of the target. Satisfactorily, using this approach to detect gliotoxin, optimal conditions for detection was achieved for reducing the detection time to 55 min, achieving a low detection limit of 2.4 fM and a satisfactory linear in the range of 50 fM to 1 nM, which addressed the shortcoming of a weak electrochemical signal in previous sensors. The water-insoluble AIE material was coupled with DNA to obtain water-soluble ETTC-dsDNA and successfully introduced into the sensor system, with a low detection limit of 5.6 fM. Subsequently, the biosensor combined with handheld electrochemical workstation was successfully applied in the detection of gliotoxin in five actual samples, with a detection range of 32.0 to 2.09 × 108 pM. This strategy not only provides a novel and effective detection platform for mycotoxins in complex food matrices but also opens a promising avenue for various molecules detection in imaging and disease diagnosis.

Diverse Synthesis of Alkenylsilanes via Pd-Catalyzed Alkenyl C-H Silylation.

Here, we disclose a general approach for the diverse synthesis of alkenylsilanes in a highly efficient, stereoselective, and atom-economic manner by leveraging the palladium-catalyzed disilylation reaction of 2-bromostyrene derivatives with hexamethyldisilane, which is suitable for the preparation of a series of disubstituted, trisubstituted, and tetrasubstituted alkenylsilanes. Furthermore, the resulting tetrasubstituted alkenylsilanes could be readily transformed into the corresponding diarylated benzosiloles, which have been proven to be a potential AIE material and a fluorene material.

Organic AIE material based on D-π-A for detecting lipid droplets in living cells and its application in photodynamic therapy

Organic AIE nanostructures are extremely important fluorescent dyes for imaging-guided photosensitizing therapy, which are capable of imaging organelles and producing ROS well, however, it remains difficulties nowadays. Here we disclose the development and assembly of a NIR AIE nanoparticle (MeTTSN) by multiple assembling chemical engineering for utilization in cellular LDs, with accurate dynamic monitoring (Pearson's coefficient of 0.981) and suitable particle size distribution (267.04 nm) in PBS solution, effective Stokes shifts (91 nm), valuable quantum yield (5.88%) in water and high bioactivity and stability, superior self-assembly and incredibly 1O2 and ROS generation. Moreover, under white light irradiation, the MeTTSN, as an ideal PS, displayed superior photosensitivity for active HepG2 cells. Furthermore, the end up living cells' co-staining imaging and flow cytometry revealed that MeTTSN could actively suppress cell growth and cause or lead to cell death. Overall, the current study presents a feasible method for LDs targeting chemical bioengineering and highlights the importance of organic AIE materials PSs medication throughout the healthcare and fluorescent imaging-guided PDT area.

Synthesis and Characterization of AIE Materials and Their Application for Anti-Counterfeit Printing

Synthesis and Characterization of AIE Materials and Their Application for Anti-Counterfeit Printing

A cyclopolymer incorporating tetraphenylethene groups in its cyclic repeating units

Although incorporating AIEgens in versatile polymer topological structures is of high interest, cyclopolymers incorporating AIEgens have rarely been reported yet. In this work, a cyclopolymer incorporating tetraphenylethene groups in its cyclic repeating units (pTPE-dMMA) is synthesized in comparison with a linear polymer with tetraphenylethene pendant side groups (pTPE-MMA). The PLQY of pTPE-dMMA in the solid state is 50.35%, higher than that of pTPE-MMA (32.06%) in the solid state. The AIE behaviors of both pTPE-dMMA and pTPE-MMA in solutions are investigated. Because of the ring-constraint, the PL color of AIE cyclopolymer is not dependent on aggregation, while the PL intensity increases as the increased cyclopolymer concentration or aggregation. Even in an ultra-dilute solution (0.002 mg/mL), pTPE-dMMA exhibits significant AIE performance as the water fraction is increased. The enhanced AIE properties of pTPE-dMMA are ascribed to the ring constraint in the side groups and dense intra-/inter-molecular stacking. This work is useful not only for the designing novel AIE materials or fluorescent dyes, but also for understanding the structure–property–function relationships of a cyclopolymer.

Polymerization-Enhanced Photophysical Performances of AIEgens for Chemo/Bio-Sensing and Therapy.

AIE polymers have been extensively researched in the fields of OLEDs, sensing, and cancer treatment since its first report in 2003, which have achieved numerous breakthroughs during the years. In comparison with small molecules, it can simultaneously combine the unique advantages of AIE materials and the polymer itself, to further enhance their corresponding photophysical performances. In this review, we enumerate and discuss the common construction strategies of AIE-active polymers and summarize the progress of research on polymerization enhancing luminescence, photosensitization, and room-temperature phosphorescence (RTP) with their related applications in chemo/bio-sensing and therapy. To conclude, we also discuss current challenges and prospects of the field for future development.

Interrogating the impact of aggregation‐induced emission nanoparticles on in vitro protein stability, ex vivo protein homeostasis, and in vivo biocompatibility

AbstractAggregation‐induced emission (AIE) materials offer promising perspectives in disease diagnosis and therapeutics given their unique optical and photochemical properties. A key step toward translational applications for AIE materials is to systematically and vigorously evaluate their biosafety and biocompatibility. While previous studies focus on cellular viability and toxicity, the impact of AIE materials on detailed stress responses manifesting cellular fitness has been less explored. Herein, this work provides the first piece of evidence to support amphiphilic functionalization of AIE nanoparticles minimizes the deterioration on proteome stability and cellular protein homeostasis (proteostasis). To this end, four scaffolds of AIE molecules were prepared, further functionalized into eight nanoparticles with two amphiphilic shells respectively, and characterized for their physicochemical properties. Thermal shift assay quantitatively demonstrates that AIE materials after amphiphilic functionalization into nanoparticles enhance proteome thermodynamic stability and ameliorate proteome aggregation propensity in cellular lysate, echoed by cell viability and fractionation experiments. Intriguingly, poor polydispersity index (PDI) of functionalized nanoparticles exaggerates their retention and aggregation in the cell. Comparative proteomic analysis uncovers that amphiphilic functionalization of AIE materials can minimize the deterioration of cellular protein homeostasis network. Finally, vigorous interrogation of functionalized AIE nanoparticles in mice model reveals the complexity of factors affecting the biocompatibility profiles in vivo, including materials’ size, PDI, and treatment frequencies. Overall, amphiphilic functionalization of AIE materials into nanoparticles is necessary to maintain proteome stability and balance cellular protein homeostasis.

Supramolecular materials based on AIEgens for photo-assisted therapy

Photo-assisted therapy has been an advancing branch in the fields of modern theranostics and nanomedicine, holding observable superiorities such as noninvasiveness, deep tissue penetration, and spatial precision. Aggregation-induced emission luminogens (AIEgens) have emerged as powerful fluorescent materials and organic optical agents capable of performing therapeutic effects under light activation. In this review, we underscore the elaborate design and fabrication of AIEgen-based supramolecular materials for applications in the scope of photo-assisted therapy, including photothermal therapy, photodynamic therapy, and photo-induced reactions. With the aid of supramolecular self-assembly, AIE materials are endowed with higher biocompatibility, better specificity, external stimuli responsiveness, and integrated functionalities. AIEgen-based self-assembled materials categorized by different supramolecular driving forces are summarized with their respective features in both structures and therapeutic effects fully described. With these highly adjustable physicochemical properties of supramolecular assemblies, the functions of such AIE materials can be considerably expanded and optimized, also opening up possibilities for controllable multimodal theranostics. In the conclusion part, perspectives and remaining challenges in this research area are discussed.

Aggregation-Induced Emission Luminogens for Cell Death Research.

Cell death is closely related to various diseases, and monitoring and controlling cell death is a promising strategy to develop efficient therapy. Aggregation-induced emission luminogens (AIEgens) are ideal candidates for developing novel theranostic agents because of their intriguing properties in the aggregate state. The rational application of AIE materials in cell death-related research is still in its infancy but has shown great clinical potential. This review discussed the research frontier and our understanding of AIE materials in various subroutines of cell death, including apoptosis, necrosis, immunogenic cell death, pyroptosis, autophagy, lysosome-dependent cell death, and ferroptosis. We hope that the new insights can be offered to this growing field and attract more researchers to provide valuable contributions.