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Photodynamic therapy (PDT) exerts its therapeutic effects by inducing apoptosis, necrosis, and microvascular damage in tumor cells, but it also causes inflammation and induces the expression of angiogenic factors, accelerating tumor metastasis and proliferation. In this study, aggregation-induced emission (AIE) photosensitizer (PS) for PDT was combined with the cyclooxygenase-2 (COX-2) inhibitor indomethacin (IMC) for cancer-selective imaging and more efficiency in inducing apoptosis in cancer cells. In detail, inhibition of COX-2-mediated AIE PS effectively targeted the Golgi apparatus (GA) of cancer cells to generate large amounts of reactive oxygen species (ROS) in situ, thereby exerting a PDT effect. Specifically, COX-2 and other key enzymes that trigger inflammation and metastasis were significantly inhibited. It had more potent anti-tumor activity (tumor inhibition rate of 64.32 %), as well as anti-metastatic and anti-proliferative effects compared to the use of usual AIE PS. [Display omitted] • TTPI was obtained by combining AIE-PS with the COX-2 inhibitor indomethacin. • TTPI precisely targeted COX-2 in the Golgi with high co-location coefficient. • PDT while inhibiting enzymes that trigger inflammation and metastasis such as COX-2. • The inhibition rate of TTPI in vivo was significantly increased to 64.32 %. [ABSTRACT FROM AUTHOR]

Targeting the organelles that generate oxidative stress and implementing oxidative stress therapy is an essential and ambitious task. As an important subcellular organelle in eukaryotic cells, the endoplasmic reticulum (ER) is significant in mediating the direction of cell metabolism and apoptosis. To achieve the goal, we rationally designed and synthesized a photosensitizer named TTQ-ER with aggregation-induced emission (AIE) characteristics. Such a probe connects the AIE-fluorophore to the glibenclamide backbone, which enables TTQ-ER to specifically target the ER and promote emission in the near-infrared region, avoiding the negative impact of autofluorescence in organisms. Meanwhile, TTQ-ER has a large stokes shift, excellent anti-photobleaching properties, and sufficient 1O 2 production (8.85-fold of Ce6). Apoptosis assay and cell migration assay further verified that excessive reactive oxygen species production by TTQ-ER in cancer cells could promote oxidative stress in the ER microenvironment and disrupt the normal biological function of ER, thus causing elevated local lipid peroxidation and inducing apoptosis in cancer cells. Consequently, this work offers informative ideas for designing a newly generation of photosensitizers to achieve accurate photodynamic therapy. Schematic diagram of TTQ-ER promoting apoptosis of cancer cells. [Display omitted] • TTQ-ER possesses bright NIR emission, large stokes shifts and precise ER targeting. • Significant ER-targeted specificity (Rr = 0.903). • Extremely high generation yield of 1O 2 (8.85-fold that of Ce6). • Superior photodynamic ablation of cancer cells. [ABSTRACT FROM AUTHOR]

Abstract Three novel thermally activated delayed fluorescence (TADF) emitters, named MCZ-B-DTM, MCZ-P2-DTM and MCZ-P3-DTM are designed and synthesized for fabricating blue emission devices. The position of nitrogen atom in pyridine ring is varied relative to the donor unit and the presence of CH⋯N hydrogen bonding in MCZ-P3-DTM is confirmed by theoretic simulation and 1H NMR analysis. Due to the introduction of CH⋯N hydrogen bonding between donor and acceptor, the dihedral angles, photophysical properties, together with thermal stabilities, of the targeted compounds are regulated ingeniously. As a consequence, MCZ-P3-DTM displays an increase of the molar extinction coefficient obviously and offers a higher PLQY of 60.1%. The TADF device adopting MCZ-P3-DTM as emitter shows a maximum external quantum efficiency (EQE) of 12.1%, which is superior to those of MCZ-B-DTM and MCZ-P2-DTM, demonstrating the introducing of intramolecular hydrogen bonding interactions between donor and acceptor is an efficient strategy for future structural design of TADF emitters. Highlights • Higher absorption coefficient achieved by introducing hydrogen bonding into the molecule. • Formation of intramolecular CH⋯N hydrogen bonding enhances the molecule rigidity with increased PLQY and EQE. • Comparative study is carried out by varied the position of nitrogen atom in pyridine. • This strategy is promising to achieve high efficient blue TADF emitters. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) combined with critical organelle targeting can maximize ablation of malignant tumors, which is a desirable route against cancer. However, the short excitation/emission wavelengths of conventional photosensitizers (PSs), the inefficient production of reactive oxygen species (ROS) and the inevitable aggregation-induced quenching phenomenon have restricted their development. Herein, we developed and synthesized a set of photoactivated fluorescent probes named MoTQu and MeTQu with aggregation-induced emission properties. The both of fluorescent probes have merits of bright near-infrared fluorescence emission, large stokes shift and enhanced intramolecular charge transfer attributed to the synergistic interaction of strong donor and acceptor of molecular. In addition, the optimal PS named MoTQu not only possesses superior anti-photobleaching, biocompatibility and extremely high-level ROS generation efficiency, on the other hand, can time-responsive target mitochondria and lysosomes in living cells to cause lysosomal dysfunction by generating large amount of ROS in situ under photoexcitation, subsequently targeting mitochondria through the positive electrical properties of the quinoline fraction, further inducing and promoting cancer cell damage and irreversible apoptosis. Consequently, we are convinced that MoTQu can be a powerful tool to foster the development of image-guided PDT. [Display omitted] • MoTQu has merit of time-responsive mitochondria and lysosomes targeting. • MoTQu have desirable advantages of large stokes shifts and bright NIR emission. • The sufficient ROS generation of MoTQu upon photoexcitation can ablate cancer cells. • Tiny doses of MoTQu under photoexcitation could suppress metastasis of cancer cells. [ABSTRACT FROM AUTHOR]

A family of near-infrared (NIR) aggregation-induced emission (AIE) photosensitizers (PSs) were designed and synthesized to modulate the spectroscopic and photochemical properties of the contained donor-acceptor (D-A) units. Stronger intermolecular charge transfer (ICT) states were promoted by the synergistic action of benzothiadiazoles and quinolines, which accelerates intersystem crossing (ISC). The best NIR AIE-PS, BTQ , showed an extremely high 1O 2 generation rate (5.6-fold of Rose Bengal) and highly efficient photodynamic killing of cancer cells. Furthermore, the mechanism by which mitochondria-targeted PSs produce large amounts of reactive oxygen species (ROS) triggering calcium ion (Ca2+) overload and opening of the mitochondrial permeability transition pore (mPTP), thereby disrupting mitochondria and leading to apoptosis, was demonstrated for the first time. This work provides an exciting benchmark for the molecular engineering of AIE-PSs targeting mitochondria and presented new insights of the development of fluorescence imaging guided photodynamic therapy (FL-G-PDT). [Display omitted] • Simple Molecular engineering to synthesize mitochondrial targeting NIR AIE photosensitizers (BTQ). • BTQ can efficiently generated singlet oxygen and precisely target mitochondria. • BTQ can open the transition pore of mitochondrial membrane permeability and reduce the mitochondrial membrane potential. • BTQ has excellent photodynamic effect on HepG2 cells under light irradiation. [ABSTRACT FROM AUTHOR]

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 1O 2 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. • MeTTSN was applied to glow brightly and high-fidelity monitoring lipids droplets. • MeTTSN has suitable particle size distribution in PBS. • MeTTSN has excellent bioactivity and photostability. • MeTTS N has been utilized effectively for the photodynamic etching of cancer cells. [ABSTRACT FROM AUTHOR]

Intramolecular through-space charge transfer (TSCT) excited state has been exploited for developing thermally activated delayed fluorescence (TADF) emitters, while the adjustment of excited state dynamics by conformational engineering is still rare. Herein, we designed a series of AIE-active TADF emitters, bearing triphenylamine as donor and phenyl ketone as acceptor unit, and the evolution of charge transfer from through-bond to through-space is realized by controlling the relative position of the donor and acceptor units. Upon transforming the charge transfer categories from through-bond to through-space, the reverse intersystem crossing (RISC) rate is progressively improved by virtue of the narrower energy split between singlet and triplet states (ΔΕ ST), meanwhile, the restricted intramolecular motion suppresses the non-radiative decay effectively, resulting in obviously improved luminescence efficiency. Appointing a bipolar blue TADF material as host to sensitize these emitters, solution-processed organic light-emitting diodes (OLEDs) based on TSCT emitter 1TCPM-Cz achieve maximum current efficiency (CE) of 35.5 cd A−1 and external quantum efficiency (EQE) of 13.3%, respectively, which is higher than that of through-bond charge transfer (TBCT) analogues. The work demonstrates a convenient design strategy to achieve high-performance TSCT emitters by regulating the conformation of the donor and acceptor. A convenient design strategy is demonstrated to achieve high-performance TSCT emitters by regulating the conformation of the donor and acceptor. Image 1 • Evolution of CT from through-bond to through-space realized by controlling the position of donor and acceptor. • Faster k RISC achieved in TSCT emitters due to the very small ΔΕ ST. • Suppressed k nr in TSCT emitters realized own to restricted intramolecular motion. • Solution-processed OLEDs realizes a higher EQE of 13.3%. [ABSTRACT FROM AUTHOR]

As dynamic subcellular organelles, lipid droplets (LDs) are associated with energy homeostasis and handling of cellular lipids and proteins, and their abnormal activity and quantity are involved in many serious diseases, even cancer. Thus, the biological morphology of LDs monitoring is very important to disease screening and biomedical research. In this work, we developed a series of aggregation-induced emission luminogens (AIEgens, TFI , MTFI and MOTFI) via very ordinary synthetic technology and convenient purification. Owing to large Stokes shifts (greater than 140 nm), bright red emissions, excellent photostability and good biocompatibility, these lipotropic AIEgens can specially accumulate in LDs and visually 'light up' them. In addition, the MTFI was successfully engaged to high-fidelity monitoring and tracking the LDs' movements in living cells. Moreover, the LO2 and HepG2 cells could be clearly distinguished according to the significantly different fluorescence intensity of MTFI marked LDs. Thus these AIEgens may become promising imaging molecule tools to investigate the physiological and pathology function of intracellular LDs, and show great potential for diagnosis of LDs-related diseases. Lipotropic nanoparticle was used for high-fidelity imaging of lipid droplets and detecting HepG2 cells from LO2 cells. Image 1 • Lipophilic NIR AIEgens was developed using a simple functional fragment assembly molecular engineering. • MTFI was used to specifically 'light up' and high-fidelity dynamically monitored LDs in living cells. • MTFI could clearly distinguish between normal liver cells and cancer liver cells. [ABSTRACT FROM AUTHOR]

Reactive sulfur species (RSS), primarily containing glutathione (GSH), cysteine (Cys), hydrogen sulfide (H 2 S) and hydrogen polysulfides (H 2 S n , n > 1), were crucial endogenous biological signal molecules. Among them, H 2 S and H 2 S n played extremely momentous roles in many physiological and pathological processes. Limited by the vivo environmental diversity and complexity, it was highly desirable to rely on the single fluorescence probe platform to visualize H 2 S n and H 2 S according different fluorescence signals. Herein, we reported a two-photon excited fluorescent probe MC-S n that had the following merits: (Ⅰ) ratiometric and colorimetric: reducing detection errors and conducting visual analysis; (Ⅱ) two-photon microscope: better performance in vivo and vitro imaging; (Ⅲ) two specific sulfide reaction sites: studying on the mutual transformation of H 2 S n and H 2 S in biological systems. Furthermore, take advantages of low cytotoxicity (cell viability ≥ 85.99%), low limit of detection (21 nM), significant photostability, excellent pH stability, quick response behavior (175 s) and high penetration depth (110 μm), MC-S n can be employed to visualize endogenous and exogenous H 2 S n and H 2 S in cells, liver tissues and zebrafish. • Ratiometric and colorimetric: reducing detection errors and conducting visual analysis. • Two-photon microscope: better performance in vivo and vitro imaging. • Two specific sulfide reaction sites: studying on the mutual transformation of H2Sn and H2S in biological systems. • Low limit of detection (21 nM) and high penetration depth (110 μm). [ABSTRACT FROM AUTHOR]