Search Results (215)

Nanotheranostics integrate theranostic functions onto a single nanoscale platform, and have become a new approach in precision medicine. Nanotheranostics rely on probes. However, traditional fluorescent probes often exhibit aggregation-caused quenching (ACQ) when loaded at high concentrations onto nanocarriers, severely limiting their imaging performance. Aggregation-induced emission agents (AIEgens) offer a solution to this long-standing problem through their ability to enhance fluorescence during aggregation. This mini-review systematically outlines nanotheranostic systems based on aggregation-induced emission (AIE). We first introduce the basic mechanism of AIE (the limitation of molecular internal motion) and its advantages over traditional fluorescent probes. Then, we discuss the design strategies of AIE nanoprobes according to the types of nanocarriers (including liposomes, polymer nanoparticles, and self-assembling systems). Additionally, we emphasize the disease-specific AIE nanotheranostic designs tailored for pathological microenvironments such as tumors, neurodegenerative diseases, and inflammatory diseases. Finally, we conduct an in-depth analysis of the current challenges hindering clinical translation, and propose future AIE nanotheranostic technologies applicable to clinical practice and the direction for personalized medicine. Full article

Three new heteroleptic copper(I) complexes of the form [Cu(N,N)(XantPhos)]PF₆ were synthesized and characterized, where N,N refers to phenyl-substituted imidazo[4,5-f][1,10]phenanthroline. All complexes were obtained as yellow powders in yields ranging 82–95% and were fully characterized by NMR spectroscopy, FT-IR, and mass spectrometry. The complexes were also redox-optically characterized. Their absorption profiles display a lower-energy metal-to-ligand charge-transfer (MLCT) band at approximately 412 nm. In solution, weak dual emission is observed, combining ligand-centered and MLCT contributions, with oxygen-dependent quenching supporting the presence of triplet character in the latter. Temperature- and solvent-dependent studies reveal thermally coupled emissive states, in which a relaxed ³MLCT state dominates at low temperatures. In the solid state, intense orange-to-red emission arises from restricted molecular motion and stabilized ³MLCT states, with C3 showing the highest efficiency. Additionally, aggregation-induced emission (AIE) is observed in solvent mixtures. These results suggest that remote substitution can influence the excited-state dynamics and aggregation-driven emission in Cu(I) complexes. Full article

A novel transition-metal-free alkyne–thiol click polymerization with 100% atom economy is reported. Using ^tBuOLi as a catalyst at 80 °C, the polymerization efficiently yields poly(vinyl sulfide)s (PVSs) with molecular weights up to 11,800 g/mol and yields up to 91%. These sulfur-rich polymers exhibit high thermal stability (T_d up to 293 °C) and high refractive indices (1.8375–1.6383) across the visible range. By integrating abundant sulfur coordination sites with aggregation-induced emission (AIE) properties, the PVS aggregates serve as high-performance fluorescent chemosensors. The sensor enables exclusive, sensitive trace detection of Pd²⁺ and Au³⁺ with remarkable anti-interference capability and pH robustness (pH 1–7). Notably, an ultrafast response (1–2 min) for Pd²⁺ is achieved, with limits of detection (LOD) reaching 7.11 × 10⁻⁷ M for Pd²⁺ and 1.06 × 10⁻⁶ M for Au³⁺, and corresponding limits of quantification (LOQ) reaching 2.37 × 10⁻⁶ M and 3.53 × 10⁻⁶ M, respectively. This methodology offers a sustainable route to heteroatom-rich macromolecules for next-generation optical engineering and environmental monitoring. Full article

The design of novel aggregation-induced emission (AIE)-active molecules represents a cutting-edge strategy for integrated phototheranostics in the second near-infrared (NIR-II) window. This review systematically outlines rational molecular engineering approaches based on D-A, D-A-D, and A-D-A systems to achieve red-shifted NIR-II absorption/emission, enhanced AIE characteristics, and balanced radiative and non-radiative decay pathways. These AIEgens enable high-contrast NIR-II fluorescence imaging (FLI) and photoacoustic imaging (PAI) for precise tumor localization, while concurrently facilitating efficient photothermal therapy (PTT) and robust photodynamic therapy (PDT) through both type-I and type-II mechanisms. Nanoformulations of these molecules exhibit excellent stability, biocompatibility, and passive targeting via the enhanced permeability and retention (EPR) effect. We further highlight representative “all-in-one” AIE platforms that demonstrate synergistic PTT/PDT under multimodal imaging guidance, offering a promising paradigm for precision cancer theranostics. Challenges and future directions in clinical translation and combination therapy are also discussed. Full article

All forms of neural communications, from cognition to emotion, are regulated by neurotransmitters, which are otherwise the chemical language of the brain. Precise detection of these neurotransmitters is essential for the perception of neurophysiology and diagnosis of neurodegenerative diseases as well. Among the existing techniques for the detection of these molecules, fluorescence sensing is evolving as a powerful approach in terms of high sensitivity, rapid response, and real-time visualization of the chemical events occurring in the neural system. In recent years, nanomaterials have transformed this field by integrating tunable optical properties, excellent photostability, and modifiable surface chemistry into biocompatible nanostructures. We summarize the recent advances of these architectures to show how the material type and dimensionality, as well as the surface functionality, play roles in sensing through the mechanisms of Förster resonance energy transfer (FRET), photoinduced electron transfer (PET), inner filter effect (IFE), and aggregation-induced emission (AIE). The discussion has also been extended to the correlation of fluorescence modulation with the selectivity and sensitivity in the mechanism-to-function relationship. The potential utility of such innovative technologies, including artificial intelligence, spectral deconvolution analysis via big data algorithms, and chip-integrated sensing, was explored as a means to enable real-time neurochemical detection. This converging area of nanotechnology and neuroscience leaves a mark not just in analytical accuracy, but also parallels human brain rhythms. Full article

We report an optical method to estimate local microviscosity in thermotropic liquid crystals using viscosity-responsive aggregation-induced emission luminogens. Pendant-type luminogens were designed by covalently attaching 4-cyano-4′-n-octyloxybiphenyl mesogens (n = 8, 10) to a bis(N,N-dialkylamino)anthracene emissive core. When introduced at 1.0 wt% into 8OCB and 10OCB, thermal and optical analyses showed that the intrinsic liquid crystal properties were essentially unchanged, indicating good structural compatibility. Temperature-dependent fluorescence and polarization measurements revealed that emission changes are governed mainly by microviscosity rather than macroscopic phase disruption. Effective microviscosity was evaluated from absolute fluorescence quantum yields using the Förster–Hoffmann relation. On this basis, the microviscosity in the nematic phase is 21 mPa·s for 8OCB upon cooling, which correlates with the enhancement in fluorescence. In the smectic phase, although the director distribution parameter remains nearly constant, the effective microviscosity is ca. 21 mPa·s for 10OCB and ca. 54 mPa·s for 8OCB, and the fluorescence varies smoothly with temperature, reflecting changes in local segmental mobility within the layered structure. These values are broadly consistent with reported viscosity ranges/trends for cyanobiphenyl-type liquid crystals. Full article

Heparin (Hep) and its clinical antidote protamine (PRO) play essential yet antagonistic roles in anticoagulant therapy, necessitating reliable analytical tools to monitor their levels and interactions. Herein, we report that coptisine chloride (COP), a natural isoquinoline alkaloid, acts as an aggregation-induced emission (AIE) sensor enabling dual-responsive fluorescence modulation toward Hep and PRO. Owing to its rigid polycyclic and intrinsically twisted molecular framework, COP displays typical AIE behavior. In a DMSO/PBS mixture (PBS fraction = 99%, v/v), COP forms strongly emissive aggregates with Hep through electrostatically driven complexation, allowing sensitive Hep detection with a limit of detection (LOD) of 0.70 μg/mL. Subsequent competitive binding of PRO to Hep disrupts the COP–Hep aggregates, giving rise to fluorescence quenching and reversible PRO sensing (LOD: 0.49 μg/mL). Theoretical calculations together with multiple characterization techniques reveal an aggregation–disaggregation mechanism governing the dual fluorescence modulation. Moreover, COP achieves accurate Hep quantification in spiked diluted human serum, affording satisfactory linearity and recoveries (LOD = 0.71 μg/mL; recoveries 98.3–101.6%). These results demonstrate that COP, a structurally simple natural AIE luminogen, serves as a sustainable, biocompatible, and accessible tool for reversible Hep and PRO analysis in complex media. Full article

Fluorescence imaging is crucial for providing detailed information in clinical practice. However, traditional first near-infrared (NIR-I) dyes such as indocyanine green (ICG) exhibit limitations such as shallow penetration depth, low contrast, and suboptimal clarity due to light scattering and autofluorescence. To overcome these drawbacks, we utilized a novel amphiphilic second near-infrared (NIR-II) aggregation-induced emission (AIE) probe (TCP) with an emission range beyond 1300 nm (NIR-IIa). Using approximately 200 co-registered NIR-I/NIR-IIa image pairs acquired with TCP, we trained a SwinUnet-based deep learning model to transform low-quality NIR-I ICG images into high-resolution NIR-IIa-like images. Owing to its superior brightness and photostability, TCP enhances in vivo fluorescent angiography, offering clearer vascular details and a higher signal-to-background ratio (SBR) in the NIR-IIa region, 2.6-fold higher than that of ICG in the NIR-I region. The deep learning model successfully converted blurred NIR-I images into high-SBR NIR-IIa-like images, achieving rapid imaging speeds without compromising quality. This work introduces a synergistic “probe-plus-AI” paradigm that substantially improves both the quality and speed of clinical fluorescence imaging, providing a pathway that is immediately translatable to enhanced diagnostics and image-guided surgery. Full article

The development of nanoscale chiral materials with enhanced optical properties holds significant promise for advancing technologies in light-emitting devices and enantioselective sensing. Here, we report the self-assembly of chiral metal–organic cages from an axially chiral, AIE-active binaphthyl dicarboxylate ligand. This supramolecular architecture functions as a multifunctional platform, demonstrating a high affinity for anionic guests through synergistic electrostatic and hydrogen-bonding interactions. The rigid cage framework not only enhances the ligand’s intrinsic aggregation-induced emission (AIE) but also serves as a highly effective chiral amplifier. Notably, MOCs significantly boost the circularly polarized luminescence (CPL), achieving a luminescence dissymmetry factor (|g_lum|) of 1.2 × 10⁻³. This value represents an approximately five-fold enhancement over that of the unassembled ligand. The photophysical properties of this chiral supramolecular system provide a strategic blueprint for designing next-generation optical nanomaterials. Full article

Organic light-emitting diodes (OLEDs) have attracted remarkable interest in display and lighting. To effectively address triplet exciton harvesting and enhance external quantum efficiency (EQE), delayed fluorescence AIEgens have gained significant prominence. The primary luminescence mechanism involves the efficient harvesting of triplet excitons via reverse intersystem crossing (RISC) channels, categorized into three types: thermally activated delayed fluorescence (TADF), hybridized local and charge transfer (HLCT), and triplet–triplet annihilation (TTA). In this review, we summarize the recent development of doped and non-doped delayed fluorescent AIEgens-based OLEDs. This review mainly discusses the molecular design strategies and photophysical properties of delayed fluorescent AIEgens and the electroluminescent properties of OLEDs as emitting layers. Finally, the challenges and prospects of delayed fluorescent AIEgens for the fabrication of OLEDs are also briefly discussed. Full article

The porcine epidemic diarrhea virus (PEDV) has inflicted substantial economic losses on the swine industry, underscoring the need for sensitive point-of-care diagnostics. While lateral flow immunoassays (LFIA) offer rapidity and ease of use, traditional labels like colloidal gold suffer from limited sensitivity. Herein, we developed an aggregation-induced emission (AIE)-based LFIA, termed PED-ALFIA, for the highly sensitive detection of the PEDV antigen. PED-ALFIA exhibited a detection limit of 2.44 × 10² TCID₅₀/mL, which represents a 256-fold improvement in sensitivity over commercial colloidal gold kits and a 4-fold enhancement compared to our previously developed PED-TRFIA. The assay showed no cross-reactivity with other common swine viruses and demonstrated high reproducibility. When tested on clinical samples (n = 42), results showed 100% concordance with qPCR. Utilizing a portable fluorescence reader, the assay can be completed within 10 min, establishing PED-ALFIA as a sensitive, specific, and rapid on-site tool for the early diagnosis of PEDV. Full article

Liposomal systems are advanced carriers of active substances which, thanks to their ability to encapsulate these substances, significantly improve their pharmacokinetics, bioavailability, and selectivity. This article presents the results of spectroscopic studies for a selected compound from the 1,3,4-thiadiazole group, namely 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl]benzene-1,3-diol (NTBD, see below in the text), in selected liposomal systems formed from the phospholipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Detailed spectroscopic analyses were carried out using electronic absorption and fluorescence spectroscopy; resonance light scattering (RLS) spectra measurements; dynamic light scattering (DLS); as well as time-resolved methods—fluorescence lifetime measurements using the TCSPC technique. Subsequently, based on the interpretation of spectra obtained by FTIR infrared spectroscopy, the preliminary molecular organization of the above-mentioned compounds within lipid multilayers was determined. It was found that NTBD preferentially occupies the region of polar lipid headgroups in the lipid multilayer, although it also noticeably interacts with the hydrocarbon chains of the lipids. Furthermore, X-ray diffraction (XRD) techniques were used to study the effect of NTBD on the molecular organization of DPPC lipid multilayers. Monomeric structures and aggregated forms of the above-mentioned 1,3,4-thiadiazole analogue were characterized using X-ray crystallography. Interesting dual fluorescence effects observed in steady-state fluorescence measurements were linked to the excited-state intramolecular proton transfer (ESIPT) effect (based on our earlier studies), which, in the obtained biophysical systems—liposomal systems with strong hydrophobicity—is greatly enhanced by aggregation-induced emission (AIE) effects. In summary, the research presented in this study, concerning the novel 1,3,4-thiadiazole derivative NTBD, is highly relevant to drug delivery systems, such as various model liposomal systems, as it demonstrates that depending on the concentration of the selected fluorophore, different forms may be present, allowing for appropriate modulation of its biological activity. Full article

Dual-mode fluorescent materials are vital in bioimaging, sensing, displays, and lighting, owing to their efficient emission of visible or near-infrared light. Traditional optimization methods, including empirical experiments and quantum chemical computations, suffer from high costs, high labor intensities, and difficulties capturing complex relationships among molecular structures, synthesis parameters, and key photophysical properties. In this review, fundamental principles, key methodologies, and representative applications of machine learning (ML) in predicting fluorescent material performance are systematically summarized. The core ML techniques covered include supervised regression, neural networks, and physics-informed hybrid frameworks. The representative fluorescent materials analyzed encompass aggregation-induced emission (AIE) luminogens, thermally activated delayed fluorescence (TADF) emitters, quantum dots, carbon dots, perovskites, and inorganic phosphors. This review details the modeling approaches and typical workflows—such as data preprocessing, descriptor selection, and model validation—and highlights algorithmic optimization strategies such as data augmentation, physical constraints embedding, and transfer learning. Finally, prevailing challenges, including limited high-quality data availability, weak model interpretability, and insufficient model transferability, are discussed. Full article

Aggregation-induced emission (AIE) luminogens are materials that exhibit enhanced light emission in the aggregated state, primarily due to the restriction of intramolecular motions, which reduces energy loss through non-radiative pathways. Tetraphenylethylene (TPE) and its derivatives are prominent examples of AIE-active materials, owing to their ease of synthesis, tuneable photophysical properties, and strong aggregation tendencies. This review provides an overview of the fundamental AIE mechanisms in TPE-based systems, with a focus on the role of restricted intramolecular rotation (RIR) and π-twisting in governing their emission behaviour. It explores the influence of molecular structure, electronic configuration, and intermolecular interactions on fluorescence properties. Furthermore, recent advances in practical applications of TPE-based AIE luminogens are highlighted across a spectrum of biological imaging domains, including cellular imaging, tissue and in vivo imaging, and organelle-targeted imaging. Additionally, their integration into multifunctional and theranostic platforms, along with the development of stimuli-responsive and self-assembled systems, underscores their versatility and expanding potential in biomedical research and diagnostics. This review aims to offer valuable insights into the design principles and functional potential of TPE-based AIE luminogens, guiding the development of next-generation materials for advanced bioimaging technologies. Full article

Graphene quantum dots (GQDs) have emerged as promising nanomaterials due to their unique optical properties, high biocompatibility, and tunable surface functionalities. In this work, GQDs were synthesized via a one-pot hydrothermal method and further functionalized using polyethylene glycol (PEG) of various molecular weights and sodium hydroxide to tailor their photoluminescence (PL) behavior and enhance their applicability in thin-film illumination and biological staining. PEG-modified GQDs exhibited a pronounced red-shift and intensified fluorescence response due to aggregation-induced emission, with GQD-PEG (molecular weight: 300,000) achieving up to eight-fold enhancement in PL intensity compared to pristine GQDs. The influence of solvent environments on PL behavior was studied, revealing solvent-dependent shifts and emission intensities. Transmission electron microscopy confirmed the formation of core–shell GQD clusters, while Raman spectroscopy suggested improved structural ordering upon modification. The prepared GQD thin films demonstrated robust fluorescence stability under prolonged water immersion, indicating strong adhesion to glass substrates. Furthermore, the modified GQDs effectively labeled E. coli, Gram-positive, and Gram-negative bacteria, with GQD-PEG and GQD-NaOH displaying red and green emissions, respectively, at optimal concentrations. This study highlights the potential of surface-functionalized GQDs as versatile materials for optoelectronic devices and fluorescence-based bioimaging. Full article