Restriction Of Intramolecular Motion Research Articles

Fluorescent Particles Based on Aggregation-Induced Emission for Optical Diagnostics of the Central Nervous System.

In 2001, Tang's team discovered a unique type of luminogens with substantial enhanced fluorescence upon aggregation and introduced the concept of "aggregation-induced emission (AIE)". Unlike conventional fluorescent materials, AIE luminogens (AIEgens) emit weak or no fluorescence in solution but become highly fluorescent in aggregated or solid states, due to a mechanism known as restriction of intramolecular motions (RIM). Initially considered a purely inorganic chemical phenomenon, AIE was later applied in biomedicine to improve the sensitivity of immunoassays. Subsequently, AIE has been extensively explored in various biomedical applications, especially in cell imaging. Early studies achieved nonspecific cell imaging using nontargeted AIEgens, and later, specific cellular imaging was realized through the design of targeted AIEgens. These advancements have enabled the visualization of various biomacromolecules and intracellular organelles, providing valuable insights into cellular microenvironments and statuses. Neurological disorders affect over 3 billion people worldwide, highlighting the urgent need for advanced diagnostic and therapeutic tools. AIEgens offer promising opportunities for imaging the central nervous system (CNS), including nerve cells, neural tissues, and blood vessels. This review focuses on the application of AIEgens in CNS imaging, exploring their roles in the diagnosis of various neurological diseases. We will discuss the evolution and conclude with an outlook on the future challenges and opportunities for AIEgens in clinical diagnostics and therapeutics of CNS disorders.

Amidine-functionalized aggregation-induced emission luminogen and a 3D-printed digital sensor platform for ultrafast and visual detection of heparin.

Heparin is a widely used anticoagulant in clinic. However, improper dosing can increase the risk of thromboembolic events, potentially leading to life-threatening complications. Clinic monitoring of heparin is very important for its use safety. Rapid and accurate point-of-care testing can significantly reduce the risk of thrombotic events. The detection of heparin using fluorescent probes has emerged as a significant area of research, driven by the need for rapid, sensitive, and selective methods for monitoring this crucial anticoagulant in clinical settings. However, the absence of convenient and user-friendly heparin testing methods continues to pose a challenge. In this work, a tetraphenylethylene derivatives with four amidine active groups (TPE-4+) was prepared. TPE-4+ has obvious aggregation-induced emission (AIE) effect on the heparin with a 127-fold enhancement occurring within just 3s. The molecular docking simulation showed that TPE-4+ was closely embedded in the heparin by the electrostatic force between four amidine of TPE-4+ and sulfate ester group of heparin, restricted intramolecular motion of TPE-4+, and causing obvious AIE features. The fluorescence intensity of TPE-4+ was line with the concentration of heparin in the range of 0-2.0 U/mL with a lowest detection limit of 0.0038 U/mL. The possible interference in the serum samples had no influence on the determination of heparin. Using 3D printing technology, a compact, portable digital sensor platform for straightforward monitoring of heparin levels was fabricated. The proposed innovative platform provides a powerful tool to make portable and real-time monitoring of heparin possible, and thereby contributing to achieve point-of-care testing and decrease the risk of thrombotic events. This novel method of combining the probe with the sensing platform simplifies the detection process and enhances patient care by providing more accurate diagnostic capabilities.

AIEgens-based luminescent metal-organic frameworks as novel electrochemiluminescence emitters Integrated with co-reaction amplification strategy for CA15-3 detection

A current research focus in the field of electrochemiluminescence (ECL) is the development of novel high-performance emitters. Herein, we reported the synthesis of a zirconium-based metal–organic framework (Zr-TBAPy-MOF) using the aggregation-induced emission luminogens (AIEgens) 1,3,6,8-tetra(4-carboxyphenyl)pyrene (H4TBAPy) as ligands and Zr6-clusters as nodes. The resulting AIE-active luminescent MOF (AIE-LMOF) exhibited superior ECL properties and was used as an ECL emitter to construct a high-sensitivity ECL immunosensor. Conceptual experiments demonstrated that Zr-TBAPy-MOF showed significantly stronger ECL emission compared to both the monomers and aggregates of H4TBAPy, attributed to the effective restriction of intramolecular motion (RIM). On the sensor substrate, we designed an Au@ZnO/Cu2O nanocomposite as a co-reactant accelerator. This significantly promoted the generation of sulfate radicals (SO4•−) from persulfate (S2O82−) through the sustainable switching of Cu+/Cu2+ oxidation states in copper oxide (Cu2O). Additionally, zinc oxide (ZnO), which had excellent electrochemical properties, further enhanced the catalytic activity of the materials. Leveraging these advantages, we developed a sandwich-type ECL immunosensor for the ultrasensitive detection of carbohydrate antigen 15–3 (CA15-3), demonstrating a wide sensitive range (0.001 − 100 U/mL) and a low detection limit (0.0007 U/mL). Overall, this work paves the way for the development of efficient ECL luminophores with significant potential in the field of immunoassays for the early diagnosis of disease.

Supramolecular assemblies with aggregation-induced emission for in situ active imaging-guided photodynamic therapy of cancer cells

Photodynamic therapy (PDT) has attracted widespread attention as a novel non-invasive anticancer approach. However, the diminished photosensitivity and limited oxygen exposure caused by the aggregation of traditional photosensitizers greatly impair its overall therapeutic efficacy. Herein, a series of water-soluble aggregation-induced emission luminogens (AIEgens) with triphenylamine as skeleton were synthesized and exhibited bright Near-infrared (NIR) emission and strong reactive oxygen species (ROS) generation. Through host-guest complexation between the multicharged triphenylamine units on AIEgens and cucurbit[10]uril (CB[10]) host molecule, supramolecular nanoassemblies were constructed and exhibited negligible phototoxicity to normal cells due to their limited oxygen contact. In contrast, the efficient release of AIEgens from nanoassemblies through competitive binding of overexpressed peptides in cancer cells with CB[10], enabled the full exploitation of the photosensitivity of AIEgens to produce highly efficient ROS, achieving selective ablation of cancer cells. Moreover, due to the restriction of intramolecular motion (RIM) upon anchored on organelle membranes through electrostatic interactions, the cationic AIEgens with weak fluorescence in physiological environment exhibited intense fluorescence emission, thus realizing imaging-guided PDT. This work may open up an avenue for the development of simple and feasible smart responsive nanomaterials for cancer treatment using supramolecular host-guest complexation strategy.

Fluorescence probe based on ZIF-8-constrained AuNCs aggregation-induced enhancement applying for specific Cu2+ detection in water and fish samples

Herein, glutathione-gold nanoclusters (GSH-AuNCs) with aggregation-induced emission (AIE) property were successfully synthesized and encapsulated within the ZIF-8 framework through self-assembly to prepare GSH-AuNCs/ZIF-8 probes. This method enhanced the fluorescence efficiency and stability of AuNCs through two aspects: (i) the AIE effect of GSH-AuNCs and (ii) the confinement effect of ZIF-8 framework, which improved the restriction of intramolecular motion (RIM) of GSH-AuNCs. The constructed GSH-AuNCs/ZIF-8 probe was demonstrated to possess strong fluorescence response and remarkable specificity towards Cu2+, as well as reliable storage stability. Under optimal conditions, the proposed fluorescent sensor exhibited a favorable linear response to Cu2+ within the concentration range of 0.1–50.0 μmol L−1 (R2 = 0.9931), with a detection limit of 0.08 μmol L−1. During the spiked analysis of tap water and fish samples, this fluorescence probe not only demonstrated good detection accuracy (recovery: 89.2–103.0 %) and reproducibility (RSD < 4.2 %, n = 3) but also enabled the rapid analysis within a short time. These results indicated that the fluorescence probe based on GSH-AuNCs encapsulated by ZIF-8 proposed an effective strategy for improving the fluorescence efficiency of AuNCs in environment and food pollutant monitoring.

Designing affinity-switchable aggregation-induced emission-enhanced supramolecular biosensors for “lighting” of endogenous trans-zeatin bioactivity in plants

Interpreting signals from the endogenous phytohormone trans-zeatin, which promotes cell division and differentiation, is essential for understanding plant growth and development. In this work, a supramolecular biosensor consisting of β-cyclodextrin (β-CD) and aggregation-induced emission-enhancing organic molecules (AIETPA) is reported. The trans-zeatin aptamer (Apt) competes with the AIETPA for preferential access to the β-CD due to the affinity difference between the host and the guest. Conversely, the presence of trans-zeatin enables the Apt to dissociate from the β-CD, as it forms a more favorable affinity with the trans-zeatin. This release of Apt from the β-CD allows AIETPA to occupy the β-CD cavity as a guest, resulting in fluorescence due to the restricted intramolecular motion (RIM). The sensor developed in this work exhibits high sensitivity (3 nM) and selectivity for trans-zeatin. More importantly, this work can monitor the total bioactivity signal of plant endogenous trans-zeatin through in situ fluorescence imaging, which holds great significance for chemical biology research.

Role of alkyl chain length on aggregation enhanced two-photon absorption and thermal diffusivity of Carbazole-Barbituric acid D-π-A systems

Aggregation Induced Emission (AIE) luminogens exhibit no or faint emission in dilute solution and are induced to emit when aggregated with restriction of intramolecular motion as the principle mechanism. We investigated the role of hydrophobic interaction in AIE effect by varying the alkyl chain length of Carbazole-Barbituric acid (CBA) D-π-A system. We synthesized six CBA conjugates, studied their photophysical properties and morphological changes upon aggregation by varying water: tetrahydrofuran ratio. We performed thermal lens experiment in all CBA conjugates to understand the variation in radiative and non-radiative decays upon aggregation. Both aggregation and hydrophobic interaction is found to play significant role in tuning thermal diffusivity of CBA conjugates. The knowledge about their energy levels was gained by using DFT in Gaussian 09 program package. Perturbation of energy levels associated with molecular aggregation open up the possibility of such D-π-A system in nonlinear optics. The open aperture Z-scan technique with Nd:YAG laser at 1064 nm was utilized to measure the change in two-photon absorption (TPA) coefficient at different stages of aggregation and as a function of alkyl chain lengths. We observed an aggregation enhanced TPA and could tune the TPA in aqueous solution by changing the alkyl chain length. Experimentally observed TPA coefficient showed the same trend as obtained in DFT calculation for hyperpolarizability. Furthermore, for practical utility we fabricated CBA conjugate doped PMMA thin films for low threshold optical limiting applications.

Ligand Meta-Anchoring Strategy in Metal-Organic Frameworks for Remarkable Promotion of Quantum Yields.

Aggregation is a conventional method to enhance the quantum yields (QYs) of pure organic luminophores due to the restriction of intramolecular motions (RIM). However, how to realize RIM in metal-organic frameworks (MOFs) is still unclear and challenging. In this work, the ligand meta-anchoring strategy is first proposed and proved to be an effective and systematic approach to restrict the intramolecular motions of MOFs for the QY improvement. By simply shifting the substituent position in the ligand from para to meta, the QY of the resulting MOF is significantly enhanced by eleven-fold. The value is even higher than that of ligand aggregates, demonstrating the strong RIM effect of this ligand meta-anchoring strategy. The introduction of co-ligand induces the appearance of visible yellow room temperature phosphorescence with a lifetime of 222 ms due to the QY enhancement and the charge transfer between the donor and accepter units. The present work thus broadens the understanding of the RIM mechanism from a new perspective, develops a novel method to realize RIM and expands the applicable objects from pure organic materials to organic-inorganic hybrid materials.

Ligand Meta‐Anchoring Strategy in Metal–Organic Frameworks for Remarkable Promotion of Quantum Yields

AbstractAggregation is a conventional method to enhance the quantum yields (QYs) of pure organic luminophores due to the restriction of intramolecular motions (RIM). However, how to realize RIM in metal–organic frameworks (MOFs) is still unclear and challenging. In this work, the ligand meta‐anchoring strategy is first proposed and proved to be an effective and systematic approach to restrict the intramolecular motions of MOFs for the QY improvement. By simply shifting the substituent position in the ligand from para to meta, the QY of the resulting MOF is significantly enhanced by eleven‐fold. The value is even higher than that of ligand aggregates, demonstrating the strong RIM effect of this ligand meta‐anchoring strategy. The introduction of co‐ligand induces the appearance of visible yellow room temperature phosphorescence with a lifetime of 222 ms due to the QY enhancement and the charge transfer between the donor and accepter units. The present work thus broadens the understanding of the RIM mechanism from a new perspective, develops a novel method to realize RIM and expands the applicable objects from pure organic materials to organic–inorganic hybrid materials.

Water bridges as the trigger in an amino functionalized Zn-MOF for highly selective and sensitive fluorescent sensing of water

Water is a fundamental element for life. The highly selective and sensitive sensing of water is always attractive for mankind in activities such as physiological processes study and extraterrestrial life exploration. Fluorescent MOFs with precise channels and functional groups might specifically recognize water molecules with hydrogen-bond interaction or coordination effects and work as water sensors. As a proof of concept, herein, an amino functionalized Zn-MOF (named as complex 1) with pores that just right for water molecules to form hydrogen bond bridges is revealed for highly selective and sensitive fluorescent sensing of water. The single-crystal X-ray diffraction analysis indicates that the 3D framework of complex 1 is functionalized with free amino groups in the channels. Hydrogen bonds formed in the channel along b-axis as water bridges to connect two adjacent NH2bdc ligands and result in the restriction of intramolecular motions (RIM) which could responsible for the selective turn-on fluorescence response to water. Complex 1 exhibits high sensitive to trace amount of water in organic solvents and could be used for water detection in a wide range water contents. Take advantages of complex 1, portable sensors (complex 1@PMMA) were prepared and used in the highly sensitive water sensing.

Combined DFT and QM/MM Modeling on Multifunctional TADF Sensitizers and Hot-Exciton Emitters via Carborane Triads for Blue Hyperfluorescent OLEDs.

The scarcity of novel luminogens significantly impedes the advancement of TADF sensitizers and hot exciton emitters, attracting considerable attention for their potential to enhance energy conversion efficiencies in hyperfluorescent OLEDs. In this study, a systematic investigation is employed to design and develop multifunctional materials based on carborane cores through DFT and TD-DFT methods. In pursuit of this objective, 45 carborane triad-type molecules were systematically designed using four donors and two acceptor units. Electronic structure calculations revealed that (i) the singlet, triplet, ΔEST, and SOC values exhibit an increased trend as the carborane core shifts from ortho to meta to para, while an increase in donor strength on the core leads to a decrease in these values. (ii) Moreover, there is a decrease in reorganization energies, absorption wavelengths, ISC, and RISC rates as the carborane switches from ortho to meta to para while witnessing an increase in donor strength. The QM/MM study reveals that para carborane's restricted intramolecular motions improve its solid-state aggregation over ortho carborane and solution phases. Interestingly, carborane triads featuring P-DMB and P-BODIPY acceptor units satisfy the desired criteria for multifunctional TADF sensitizers and hot exciton emitters, respectively.

Loading of AuNCs with AIE effect onto cerium-based MOFs to boost fluorescence for sensitive detection of Hg2+

Ligand-protected gold nanoclusters (AuNCs) have become promising nanomaterials in fluorescence (FL) methods for mercury ions (Hg2+) monitoring, but low FL efficiency hinders their widespread application. Herein, AuNCs/cerium-based metal-organic frameworks (AuNCs/Ce-MOFs) were prepared by loading 6-aza-2-thiothymine-protected AuNCs (ATT-AuNCs) with aggregation-induced emission (AIE) effect on the surface of Ce-MOFs by electrostatic attraction. This strategy improved the FL intensity of AuNCs through two aspects: (i) the AIE effect of ATT-AuNCs and (ii) the confinement effect of Ce-MOFs, which improved the restriction of intramolecular motion (RIM) of ATT-AuNCs. In addition, Ce-MOFs could adsorb and aggregate Hg2+ during detection, which might increase the local concentration. Therefore, based on the high FL signal of AuNCs/Ce-MOFs and enriched Hg2+, sensitive detection of Hg2+ could be achieved. More importantly, the strong specific recognition between AuNCs and Hg2+ could guarantee selectivity. The developed FL sensor exhibited superior detection performances with a wide linear range of 0.2–500 ng mL−1 and a low detection limit of 0.067 ng mL−1. Furthermore, the FL sensor used for sensitive and selective detection of Hg2+ in real samples, and the results agreed well with the standard method. In summary, this work proposed an effective and generalized strategy for improving the FL efficiency of AuNCs, which would greatly facilitate their application in pollutant monitoring.

A Rationally Designed Prodrug for the Fluorogenic Labeling of Albumin and Theranostic Effects on Drug-Induced Liver Injury.

The development of small-molecular fluorogenic tools for the chemo-selective labeling of proteins in live cells is important for the evaluation of intracellular redox homeostasis. Dynamic imaging of human serum albumin (HSA), an antioxidant protein under oxidative stress with concomitant release of antioxidant drugs to maintain redox homeostasis, affords potential opportunities for disease diagnosis and treatment. In this work, we developed a nonfluorogenic prodrug named TPA-NAC, by introducing N-acetyl-l-cysteine (NAC) into a conjugated acceptor skeleton. Through combined thiol and amino addition, coupling with HSA results in fluorescence turn-on and drug release. It was reasoned that the restricted intramolecular motion of the probe under an HSA microenvironment after covalent bonding inhibited the nonradiative transitions. Furthermore, the biocompatibility and photochemical properties of TPA-NAC enabled it to image exogenous and endogenous HSA in living cells in a wash-free manner. Additionally, the released drug evoked upregulation of superoxide dismutase (SOD), which synergistically eliminated reactive oxygen species in a drug-induced liver injury model. This study provides insights into the design of new theranostic fluorescent prodrugs for chemo-selective protein labeling and disease treatments.

Two novel chiral AIEgens as coordination precursors: synthesis, structures and photophysical study

Two novel chiral molecules, (4S)-5,5-dimethyl-2-(4-oxo-4H-chromen-3-yl)thiazolidine-4-carboxylic acid (OCCA) and (4S)-5,5-dimethyl-2-(4-(1,2,2-triphenylvinyl)phenyl)thiazolidine-4-carboxylic acid (TPCA), were successfully synthesized by aldehyde amine condensation reaction, and their structures were characterized by 1H NMR and single crystal X-ray diffraction. The intensities of photoluminescence changed with the aggregation, exhibiting that OCCA and TPCA are aggregation-induced emission luminogens (AIEgens). After complete aggregation, OCCA emitted the purple-blue light at the peak of 388 nm and TPCA emitted the cyan light at the peak of 488 nm. The aggregation-induced emission (AIE) effects for OCCA and TPCA resulted from local state to twisted intermolecular charge transfer (TICT) and restriction of intramolecular motion (RIM), respectively. Other spectra including UV–vis, IR, and Raman spectra were also discussed in detail.

Aminoguanidine-based bioactive proligand as AIEE probe for anticancer and anticovid studies.

The emission features of a novel bioactive compound, 1,3-bis(2-hydroxy-3,5-diiodophenyl-methylideneamino)guanidine is found impressive with aggregation induced emission enhancement. The nitrogen and iodine rich multidentate proligand was characterized physicochemically. SCXRD and Hirshfeld surface investigation have revealed the presence of significant triangular iodine bonding apart from hydrogen bonding, weak C-H⋯π and π⋯π intermolecular interactions. These interactions collectively contribute to the solid-state packing arrangement of the molecules within the crystal lattice. The band gap of the compound was estimated experimentally and is supported with theoretical calculations. The solid-state fluorescence quantum yield of Φ = 0.36 emphasizes the utility of the proligand and the AIEE characteristics is attributed to restricted intramolecular motions as indicated by fluorescence lifetime decay studies. Strong interaction of the compound with calf thymus DNA was explored experimentally and found to align with in silico docking results. Notably, in vitro anticancer assessment on MCF-7 breast cancer cells show an IC50 value of 181.05 μg mL-1 and signifying its potent cytotoxic properties. Also, the compound is found to have lesser cytotoxicity against L929 normal cell line with an IC50 value of 356.54 μg mL-1. Computational studies further underscore the exceptional binding affinity with active sites in the SARS-CoV-2 main protease 3CLpro, surpassing established repurposed drugs. Furthermore, the proligand demonstrates excellent putative affinity towards the SARS-CoV-2 spike glycoprotein, accompanied by its distinctive AIEE attributes, drug likeness and DNA binding capability rendering it a valuable tool for prospective research investigations.

Polystyrene-Based Matrix to Enhance the Fluorescence of Aggregation-Induced Emission Luminogen for Fluorescence-Guided Surgery.

Achieving ultrabright fluorogens is a key issue for fluorescence-guided surgery (FGS). Fluorogens with aggregation-induced emission (AIEgens) are potential agents for FGS on the benefit of the bright fluorescence in physiological conditions. Herein, the fluorescence brightness of AIEgen is further improved by preparing the nanoparticle using a polystyrene-based matrix and utilizing it for tumor FGS with a high signal-to-background ratio. After encapsulating AIEgen into polystyrene-poly (ethylene glycol) (PS-PEG), the fluorescence intensity of the prepared AIE@PS-PEG nanoparticles is multiple times that of nanoparticles in 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-poly (ethylene glycol) (DSPE-PEG), a commonly used polymer matrix for nanoparticle preparation. Molecular dynamics simulations suggest that higher free energy is required for the outer rings of AIEgen to rotate in polystyrene than in the DSPE, indicating that the benzene rings in polystyrene can restrict the intramolecular motions of AIEgen better than the alkyl chain in DSPE-PEG. Fluorescence correlation microscopy detections suggest that the triplet excited state of AIEgens is less in PS-PEG than in DSPE-PEG. The restricted intramolecular motions and suppressed triplet excited state result in ultrabright AIE@PS-PEG nanoparticles, which are more conducive to illuminating tumor tissues in the intestine for FGS. The illumination of metastatic tumors in lungs by AIE@PS-PEG nanoparticles is also tried.

A triphenylamine-based near-infrared fluorescence turn off probe for nitroreductase imaging

Nitroreductase (NTR) is an essential biomarker for various diseases and widely used to evaluate the hypoxia status in tumor cells. In this work, we developed a near-infrared (NIR) fluorescence “on-off” probe PTP based on a triphenylamine scaffold, with an intrinsic long wavelength emission more than 700 nm. This probe showed typical aggregation-induced emission (AIE) properties with the increase of PBS fraction (fw), which might be attributed to the restriction of intramolecular motions (RIM) effect in high aqueous solution. The frontiers molecular orbitals (FMO) of the probe PTP and the resulting reduction compounds (PT-OH and TPA-OH) were calculated to determine their structure differences. The two nitro groups were reduced in response to NTR and then released the substance TPA-OH through the 1,6-rearrangement-elimination, resulting in simultaneous fluorescence decrease. This process was also demonstrated by the DFT/TD-DFT and docking calculations, indicating a favorable structural and spatial match between the probe and NTR. More importantly, the probe was successfully used to visualize the NTR distribution in living A431 cells with nontoxicity. It exhibited a time-dependent fluorescence quenching behavior at the cellular level, making it of great potential in NTR detection for other biosystems.

Synergistically Boosting the Circularly Polarized Luminescence of Functionalized Pillar[5]arenes by Polymerization and Aggregation.

Supramolecular polymers based on chiral macrocycles have attracted increasing attention in the field of circularly polarized luminescence (CPL) owing to their unique properties. However, the construction of macrocyclic supramolecular polymers with highly efficient CPL properties in aggregate states still remains challenging. Herein, w e constructed a class of macrocycle-based coordination polymers by combining the planar chiral properties of pillar[5]arene with the excellent fluorescence properties of aggregation-induced emission luminogens. The formation of polymers enhances both the fluorescence and chiral properties, resulting in chiral supramolecular polymers with remarkable CPL properties. Increasing the aggregation degree of the polymers can further improve their CPL properties, as evidenced by a 21-fold increase in the dissymmetry factor and an over 25-fold increase in the fluorescence quantum yield in the aggregate state compared to the solution state. Such a synergistic effect of polymerization- and aggregation-enhanced CPL can be explained by the restriction of intramolecular motions and aggregation-induced conformation confinement. This work provides a promising method for developing highly efficient CPL supramolecular polymers.

Aggregation-Induced Enhanced Electrochemiluminescence from Tris(bipyridine)ruthenium(II) Derivative Nanosheets for the Ultrasensitive Detection of Human Telomerase RNA.

The traditional tris(bipyridine)ruthenium(II) complex suffers from the notorious aggregation-caused quenching effect, which greatly compromises its electrochemiluminescence (ECL) efficiency, thus hindering further applications in biosensing and clinical diagnosis. Here, the ultrathin tetraphenylethylene-active tris(bipyridine)ruthenium(II) derivative nanosheets (abbreviated as Ru-TPE NSs) are synthesized through a protein-assisted self-assembly strategy for ultrasensitive ECL detection of human telomerase RNA (hTR) for the first time. The synthesized Ru-TPE NSs exhibit the aggregation-induced enhanced ECL behavior and excellent water-dispersion. Surprisingly, up to a 106.5-fold increase in the ECL efficiency of Ru-TPE NSs is demonstrated compared with the dispersed molecules in an organic solution. The restriction of intramolecular motions is confirmed to be responsible for the significant ECL enhancement. Therefore, this proposed ECL biosensor shows high sensitivity and excellent selectivity for hTR based on Ru-TPE NSs as efficient ECL beacons and the catalytic hairpin assembly as signal amplification, whose detection limit is as low as 8.0fm, which is far superior to the previously reported works. Here, a promising analytical method is provided for early clinical diagnosis and a new type of efficient ECL emitters with great application prospects is represented.

Triphenylamine-Based N,O-Bidentate BF2 -Enolimine Initiator for Three-Arm Star Polymethacrylates with Dual-State Fluorescent Emission.

Three-arm star polymethacrylates with dual-phase (solution and solid-state) fluorescent emission have been synthesized via atom transfer radical polymerization (ATRP) using a triphenylamine-derived organboron complex (TAPA-BKI-3Br) as initiator. The as-synthesized three-arm star polymethacrylates exhibited bright emission in both solution and the solid states due to the highly twisted structure and intramolecular charge transfer (ICT) effect of TAPA-BKI core, as well as the steric effect and restriction of intramolecular motions from the polymer arms. And the polymer chains have an important influence on the photophysical behavior of the as-synthesized three-arm star polymethacrylates in the aggregated state.