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Comprehensive Summary: Currently, solid‐state fluorescent carbonized polymer dots (CPDs) have attracted attention increasingly due to their applications for optoelectronic display. However, designing CPDs possessing solid‐state fluorescence and clarifying the fluorescence mechanism remain challenging. Herein, we initially synthesized a novel type of polythiophene derivatives CPDs, poly‐4,4'‐(thiophene‐3,4‐diyl)dibenzoic acid carbonized polymer dots (PDBA‐CPDs) with solid‐state fluorescence. Subsequently, the structural and optical characterization revealed that the solid‐state fluorescence originated from the aggregation induced emission of the CPDs. In brief, in aggregation state, the remaining polymer structure groups on the surface of the CPDs overlapped and weakened the non‐radiative transition, enhancing solid‐state fluorescence emission. Thirdly, three polythiophene‐derived CPDs were designed to further demonstrate the aggregation induced solid‐state fluorescence mechanism. Finally, owing to their unique properties of solid‐state fluorescence, the white LEDs (light emitting diodes) were fabricated with high color rendering index (CRI) of 82.7 and CIE coordinates of (0.37, 0.39) using commercial 460 nm chip. This work facilitates the development of CPDs' solid‐state fluorescence mechanisms and advances the application of CPDs in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

The development of a fluorescent probe to distinguish between cysteine (Cys) and homocysteine (Hcy) is always a challenge owing to their structural similarity, and the simultaneous detection of Cys and Hcy by utilizing different emission channels is especially difficult. In this work, we designed and synthesized a new fluorescent probe to differentiate between Cys and Hcy on the basis of a coumarin derivative with a chlorine atom and an α,β-unsaturated aldehyde. Cys and Hcy induced different cascade reactions with the probe, which led to different products with distinct photophysical properties. The nonfluorescent probe responded to Cys and emitted strong blue fluorescence, whereas it reacted with Hcy and generated yellow fluorescence without interference from glutathione. In addition, the probe was successfully applied to distinguish between Cys and Hcy in living cells. [ABSTRACT FROM AUTHOR]

Fluorescence imaging is a promising tool for the visualization of biomolecules in living systems and there is great demand for new fluorescent dyes that absorb and emit in the near-infrared (NIR) region. Herein, we constructed three new fluorescent dyes ( NBC dyes) based on keto-benzo[ h]coumarin ( k-BC) and benzopyrilium salts. These dyes showed large Stokes shifts (>100 nm) and NIR emission (>800 nm). The relationship between the structures and optical properties of these dyes was further investigated by using density functional theory calculations at the B3LYP/6-3G level of theory. Fluorescence images indicated that the fabricated dyes exhibited good photostability and low cytotoxicity and, thus, have potential applications as imaging agents in living cells and animals. [ABSTRACT FROM AUTHOR]

During the past decade, fluorescent chemosensors have become an important research field of supramolecular chemistry and have attracted great attention because of their simplicity, high selectivity and sensitivity in fluorescent assays. In the design of new fluorescent chemosensors, exploration of new sensing mechanisms between recognition and signal reporting units is of continuing interest. Based on different photophysical processes, conventional sensing mechanisms including photo-induced electron transfer (PET), intramolecular charge transfer (ICT), metal–ligand charge transfer (MLCT), twisted intramolecular charge transfer (TICT), electronic energy transfer (EET), fluorescence resonance energy transfer (FRET), and excimer/exciplex formation have been investigated and reviewed extensively in the literature. This tutorial reviewwill mainly focus on new fluorescent sensing mechanisms that have emerged in the past five years, such as aggregation-induced emission (AIE) and CN isomerization, which can be ascribed to fluorescence changes viaconformational restriction. In addition, excited-state intramolecular proton transfer (ESIPT) has not been well reviewed yet, although a number of chemosensors based on the ESIPT mechanism have been reported. Thus, ESIPT-based chemosensors have been also summarized in this review. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Currently, solid‐state fluorescent carbonized polymer dots (CPDs) have attracted attention increasingly due to their applications for optoelectronic display. However, designing CPDs possessing solid‐state fluorescence and clarifying the fluorescence mechanism remain challenging. Herein, we initially synthesized a novel type of polythiophene derivatives CPDs, poly‐4,4'‐(thiophene‐3,4‐diyl)dibenzoic acid carbonized polymer dots (PDBA‐CPDs) with solid‐state fluorescence. Subsequently, the structural and optical characterization revealed that the solid‐state fluorescence originated from the aggregation induced emission of the CPDs. In brief, in aggregation state, the remaining polymer structure groups on the surface of the CPDs overlapped and weakened the non‐radiative transition, enhancing solid‐state fluorescence emission. Thirdly, three polythiophene‐derived CPDs were designed to further demonstrate the aggregation induced solid‐state fluorescence mechanism. Finally, owing to their unique properties of solid‐state fluorescence, the white LEDs (light emitting diodes) were fabricated with high color rendering index (CRI) of 82.7 and CIE coordinates of (0.37, 0.39) using commercial 460 nm chip. This work facilitates the development of CPDs' solid‐state fluorescence mechanisms and advances the application of CPDs in the field of optoelectronics. [ABSTRACT FROM AUTHOR]

As phototheranostic agents, carbon dots (CDs), have recently drawn considerable attention due to their excellent physicochemical properties. However, the complex synthetic route and high-cost of CDs greatly limit their practical application. To address this issue, given their nearly infinite supply from nature, Hypocrella bambusae is used as the precursor for the preparation of CDs in this study. The obtained Hypocrella bambusae CDs (HBCDs) possess good water solubility, broad absorption (350–800 nm), red-light emission (maximum peak at 610 nm), and low biotoxicity. Moreover, HBCDs can highly generate 1 O 2 (0.38) and heat (27.6%) under 635 nm laser irradiation. These excellent properties of HBCDs capacitate them to be utilized for bimodal fluorescence/photoacoustic imaging-guided synergistic photodynamic therapy (PDT)/photothermal therapy (PTT). This work provides a new candidate for tumor treatment with the combination of PDT and PTT, and explores a novel approach for the preparation of CD-based phototheranostic agents with natural biomass as raw carbon sources. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Multifunctional liposomes with tumor targeted drug delivery and imaging. • Enhanced photoluminescence emission of carbon dots. • Enhanced anti-cancer efficacy of cinobufagin after loading into liposomes. Abstract Integrating the optical properties of near-infrared fluorescent carbon dots into liposomes may construct a multifunctional nano-system with the potential as a drug carrier, tracer and efficacy intensifier of the anticancer agent. In this study, the liposomes loaded with hydrophilic near-infrared carbon dots as a nano-carrier and tracer of lipophilic anticancer agent cinobufagin were developed. Prepared liposomes were characterized by particle size, morphology and entrapment efficiency. The drug release behavior, the tracer function, the anticancer effect and the side effect were investigated in vitro and in vivo. It was observed that the photoluminescence emission of carbon dots could be strongly enhanced up to 5 times by nano-liposomes. Due to this property, the bio-imaging of CDs + CB liposomes in vitro and in vivo could be clearly obtained. Our results also showed that the CDs + CB liposomes could be uptaken by cells (the lysosomes targeted) and delivered to the tumor site, and undoubtedly, the CDs + CB liposomes demonstrated sustained drug release, enhanced anticancer efficacy and low side effects in vivo. With the assistance of imaging function of CDs, the CDs + CB liposomes can easily display the distribution of drugs, which is very helpful for drug development and may open a novel avenue for drug delivery. [ABSTRACT FROM AUTHOR]

On base of the good optical properties of coumarin and fluorescein, we designed and synthesized two coumarin/fluorescein-fused fluorescent dyes ( CF dyes), which enlarged the emission wavelength and increased the Stokes shift of fluorescein moiety. The corresponding optical properties of CF dyes were investigated in detail. CF dyes could easily introduce other groups to design different functional molecules. CF dyes also exhibited rapid and sensitive responses to pH values in the range of 4.0–7.4 through the characterization of absorption and fluorescence spectra in buffer solution. More importantly, CF ethyl ester dye ( CFE dye) not only showed good cell membrane permeability and low cytotoxicity, but also had the ability to rapidly monitor mitochondrial pH changes in living cells. [ABSTRACT FROM AUTHOR]

A fluorescent probe ( 1 ) for distinguishing amongst biothiols, including cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), is developed based on different cascade reactions. The key design feature of fluorescent probe 1 is the integration of two potential reaction groups for the thiol and amino groups of biothiols in one molecule. By reacting with the halogen atom and α, β-unsaturated malonitrile in probe 1 , Cys, Hcy and GSH can generate a total of three main products with distinct photophysical properties. Probe 1 shows a strong fluorescence turn-on response to Cys with blue–green emission by using an excitation wavelength of 390 nm. At an excitation wavelength of 500 nm, probe 1 responds to GSH over Cys and Hcy and emits strong orange fluorescence. The discrimination of biothiols can be demonstrated by cell imaging experiments, indicating that probe 1 can be a useful tool for the selective imaging of Cys and GSH in living cells. [ABSTRACT FROM AUTHOR]