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Light‐mediated therapies such as photodynamic therapy (PDT) are considered emerging cancer treatment strategies. However, there are still lots of defect with common photosensitizers (PSs), such as short emission wavelength, weak photostability, poor cell permeability, and low PDT efficiency. Therefore, it is very important to develop high‐performance PSs. Recently, luminogens with aggregation‐induced emission (AIE) characteristics and red/near‐infrared (NIR) emissive have been reported as promising PSs for image‐guided cancer therapy, due to them being able to prevent autofluorescence in physiological environments, their enhanced fluorescence in the aggregated state, and generation of reactive oxygen species (ROS). Herein, we developed PSs named TBTCPM and MTBTCPM with donor–acceptor (D–A) structures, strong red/NIR, excellent targeting specificities to good cell permeability, and high photostability. Interestingly, both of them can efficiently generate ROS under white light irradiation and possess excellent killing effect on cancer cells. This study, thus, not only demonstrates applications in cell image‐guided PDT cancer therapy performances but also provides strategy for construction of AIEgens with long emission wavelengths. [ABSTRACT FROM AUTHOR]

Phototheranostic agents have thrived as promising tools for cancer theranostics because of the integration of sensitive in situ fluorescence imaging and effective multi‐model synergistic therapy. However, how to manipulate the intangible photon energy transfer to balance the competitive radiative and nonradiative processes is still challenging. Although numerous phototheranostic molecules are reported, their complicated molecular design and tedious synthesis often stumble further their development. Herein, three simple molecules with electron donating−accepting structures are developed. The electron acceptor engineering on molecules by introducing acridinium unit gives rise to TPEDCAc with aggregation‐induced second near‐infrared emission (AIE NIR‐II), high reactive oxygen species generation capability, and excellent photothermal conversion efficiency (44.8%) due to the drastic intramolecular motion of large acridinium rotor and balanced AIE effect. Experimental analysis and calculation on the controlled molecules suggested that large torsional angle and the strong electron‐withdrawing ability of the acridinium unit are keys for NIR‐II emission and balanced photodynamic/photothermal conversion. Impressively, the positively charged TPEDCAc shows mitochondria‐targeting capability and high performance in in vivo multi‐modal cancer theranostics under NIR laser irradiation. Hence, this work not only provides a single NIR‐II AIE‐based multi‐modal cancer theranostic system but inspires new insights into future development of new theranostic platforms. [ABSTRACT FROM AUTHOR]

Platinum(II) coordination‐driven architectures have exhibited unique features in fabricating functional supramolecular materials. By introducing luminescent moieties into the ligand structure, various light‐emitting metallacycles and metallacages have been facilely prepared, presenting specific applications in chemical sensing, light‐harvesting, and bio‐imaging. Except for building up the metal–ligand bonds, the platinum(II) center should also benefit the ultimate luminescence due to its unique photophysical traits. Here, a platinum(II) metallacycle with deep‐red emission for solution‐processed organic light‐emitting diodes is reported. This metallacycle is assembled by mixing a 180° di‐Pt(II) acceptor with a pyridyl‐decorated ligand functionalized by a deep‐red fluorescent emitter. Notably, the platinum(II) acceptor permits the efficient intramolecular transfer of all electrically generated singlet and triplet excitons from itself to the fluorescent moiety, which dramatically enhances the external quantum efficiency of the device compared with the one consisting of the sole ligand. The present results reveal the function of platinum(II) metallacycles in light‐emitting devices, a finding which should apply to other coordination‐driven architectures with versatile properties. [ABSTRACT FROM AUTHOR]

Organic materials with multiple emissions tunable by external stimuli represent a great challenge. TTPyr, crystallizing in different polymorphs, shows a very rich photophyisics comprising excitation‐dependent fluorescence and phosphorescence at ambient conditions, and mechanochromic and thermochromic behavior. Transformation among the different species has been followed by thermal and X‐ray diffraction analyses and the emissive features interpreted through structural results and DFT/TDDFT calculations. Particularly intriguing is the polymorph TTPyr(HT), serendipitously obtained at high temperature but stable also at room temperature, whose non‐centrosymmetric structure guarantees an SHG efficiency 10 times higher than that of standard urea. Its crystal packing, where only the TT units are strongly rigidified by π‐π stacking interactions while the Pyr moieties possess partial conformational freedom, is responsible for the observed dual fluorescence. The potentialities of TTPyr for bioimaging have been successfully established. [ABSTRACT FROM AUTHOR]

Fluorescence‐based techniques have found potential biomedical applications owing to their high sensitivity, rapid response, and in situ characteristics. Traditional fluorescent probes suffer from aggregation‐caused quenching effects, which limit their usage at high concentrations or in nanoparticles. Aggregation‐induced emission (AIE), on the other hand, is a phenomenon wherein luminogens are non‐emissive in dilute solutions but highly emissive in the aggregate and solid states. AIE bioconjugates formed by covalent linkage of AIE luminogens to biomolecules are especially promising candidates for biomedical applications because they show excellent biocompatibility, good water solubility, high specificity to the target of interest, wide functionality, and smart responsiveness. This review summarizes the methodologies in synthesizing AIE bioconjugates and their intricate applications in biosensing, bioimaging, image‐guided therapy, and "Lab‐in‐cell" over the past 20 years. Perspectives are also shared to inspire enthusiasm and motivate researchers to further develop this emerging field. [ABSTRACT FROM AUTHOR]

In this work, we aim to develop cancer cell‐targeting AIE dots based on a polyyne‐bridged red‐emissive AIEgen, 2TPE‐4E, through the combination of metabolic engineering and bio‐orthogonal reactions. Azide groups on a tumor were efficiently produced by intravenous injection of Ac4ManNAz and glycol‐metabolic engineering. These bio‐orthogonal azide groups could facilitate the specific targeting of DBCO‐AIE dots to the tumor cells undergoing metal‐free click reaction in vivo. The efficiency of this targeting strategy could be further improved with the development of new bio‐orthogonal chemical groups with higher reactivity and a large amount of AIEgens could be delivered to the tumor for diagnosis. Bridging the gap: Bio‐orthogonal red‐emissive AIE dots based on the polyyne‐bridged AIEgen were fabricated through the nanoprecipitation method using DBCO‐decorated PEG‐lipids as encapsulation matrices. Furthermore, a two‐step in vivo metabolic enhanced labeling strategy for in vivo cancer‐targeting delivery was developed. Various hydrophobic AIEgens can be delivered to disease areas with abnormal metabolic processes. [ABSTRACT FROM AUTHOR]

Visualizing behaviors of cell populations within living multicellular organisms in real time is of great value to life science but challenging due to the lack of ideal probes. In this work, a biocompatible fluorogen, azide-functionalized tetraphenylethene pyridinium (TPE-PyN3), is reported for noninvasive imaging and sensing within living systems. TPE-PyN3 exhibits unique aggregation-induced emission (AIE) attributes and high affinity to mitochondria, enabling it to achieve specific mitochondrial imaging and long-term cellular observing with excellent photostability both in vitro and in vivo. The high membrane penetrability of TPE-PyN3 allows all of the cells within the living zebrafish embryos to be morphologically visualized and reconstructed in 3D. Moreover, TPE-PyN3 is capable of indicating cell apoptosis because of its sensitivity to the change of mitochondrial membrane potential. The findings presented here provide a simple and noninvasive tool for studying behaviors of cell populations in vivo for the first time by a small-molecule AIE probe. [ABSTRACT FROM AUTHOR]

The detection of , such as DNA and RNA, plays a significant role in , forensics, and bioinformatics. Traditional nucleic acid probes are mainly intercalators, which are potential mutagens, or groove binders that show high preference only for double-stranded DNA. We herein present two versatile fluorescent probes for nucleic acid detection and visualization. The nonemissive tetraphenylethene derivatives (TTAPE) are induced by DNA/RNA to emit, thereby showing a novel phenomenon of aggregation-induced emission (AIE). This kind of 'light-up' property enables the quantitation and visualization of in aqueous solution and electrophoretic gels, respectively. The cationic TTAPE can penetrate cells with a compromised plasma membrane easily but cannot enter live cells with an intact membrane, thus making them useful for the differentiation between dead and live cells. On account of the high binding affinity to DNA, TTAPE can selectively label the chromosomes and nuclei in fixed cells, which provides a simple and fast method for the observation of cell mitosis. Owing to their AIE characteristics, the dye molecules aggregate in DNA-rich regions and exert appreciable quantum efficiency as well as superior photostability. [ABSTRACT FROM AUTHOR]

Acetylenic polymers are a group of specialty materials with novel properties. In this paper, recent progress in the development of functional acetylenic polymers is summarized. These polymers are synthesized through different polymerization approaches such as Sonogashira polycoupling, decarbonylative chloroarylation polyaddition, and polycyclotrimerization. Efforts in the development of new monomers and catalyst exploration as well as reaction optimization have lead to a large quantity of linear and hyperbranched polymers with high molecular weights and good processability. The polymer functionalization is realized by incorporating functional units into the monomer structures, which endow the resulting polymers with fascinating properties such as aggregation-induced emission, optical nonlinearity, light refractivity, photosensitivity, photopatternability, redoxactivity, and magnetism. [ABSTRACT FROM AUTHOR]

A facile approach to thermally stable and efficient solid-state emitters is proposed. By hooking up tetraphenylethene (TPE) units through aryl linkers under Suzuki coupling conditions, a series of arylene bis(tetraphenylethene)s (TPE-Ar-TPE Ar=2,5-dimethyl-1,4-phenylene, 2,5-bis(hexyloxyl)-1,4-phenylene, 1,5-naphthylene, and 9,10-anthracenylene) are prepared in satisfactory to high yields (67-96 %). These molecules are nonluminescent when dissolved in solutions but become highly emissive when aggregated in poor solvents or fabricated as thin film in the solid state, displaying a phenomenon of aggregation-induced emission. Fluorescence quantum yields of 100 % were achieved in the amorphous films of the luminogens. The luminogens exhibit mechano-, vapo-, and thermochromism: their emissions can be repeatedly switched between blue and blue-green colors by simple grinding-fuming and grinding-heating cycles owing to the morphological change from a crystalline to an amorphous state and vice versa. These compounds are thermally stable, losing little of their weight at high temperatures of 421-452 °C. All the luminogens are morphological stable with high glass transition temperatures. Multilayer light-emitting diodes with a device configuration of ITO/NPB/dye/TPBi/Alq3/LiF/Al are fabricated, which emit sky-blue electroluminescence with maximum luminance and external quantum efficiency of 7900 cd m−2 and 2.1 %, respectively. [ABSTRACT FROM AUTHOR]