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[Display omitted] Fluorescent red-emissive carbon dots (RCDs) were synthesized using the solvothermal method with citric acid as a carbon source, N , N -dimethylformamide as a nitrogen source, and formamide as a solvent. The as-synthesized RCDs show red fluorescence in an aqueous solution and have an excellent stability towards photobleaching as well as extremely low cytotoxicity and are successfully used for cell and zebrafish imaging. The results indicate that RCDs have potential applications in both in vitro and in vivo bioimaging. [ABSTRACT FROM AUTHOR]

A new coumarin-based probe 3-acetyl-7-diethylaminocoumarinthiosemicarbazone (DCT) is synthesized for Al3+ fluorescence detection in CH 3 CH 2 OH/H 2 O (6 : 4, v / v). The fluorescence intensity at 428 nm was enhanced about 15-fold with the fluorescence changed from colorless to blue. The binding constantof Al3+ with DCT is 5.04 × 106 M−1. The limit of detection (LOD) of Al3+ is calculated to be 82 nM. Furthermore, the binding details are determined by Job's plot and ESI - MS studies, which indicated that a stoichiometric ratio of 1 : 1 complex is formed between Al3+ and DCT. Cell imaging confirmed that DCT could useful for detecting Al3+ in HepG2 cells. • Probe DCT is highly selective and sensitive towards Al3+in aqueous solution phase with LOD is 82 nM,which could monitor intracellular Al3+ levels. • The mechanism indicated that a ratio of 1 : 1 complex is formed between Al3+ and DCT. [ABSTRACT FROM AUTHOR]

Isatin-3-(7′-Methoxychromone-3′-methylidene) hydrazone (L) was synthesized based on chromone schiff base, and used to construct a novel sensor to detect Cr3+. Fluorescence detection experiments were carried out for a range of different concentrations of Cr3+ in aqueous solutions. A concentration calculation model was built on the basis of eliminating interference of excitation spectrum in the fluorescence spectra with mathematical method. Results showed that probe L displayed a 70 -fold fluorescence enhancement upon the addition of Cr3+ due to the photo-induced electron transfer (PET) effect. On the other hand, metal ions except Cr3+ did not cause significant change in either the absorption or the fluorescence spectrum of L. In addition, L showed a good selectivity to Cr3+ over other metal cations, especially Al3+ and Cu2+. The probe L can detect Cr3+ highly and selectively by the direct chelation enhanced fluorescence with a detection limit of 3.14 × 10−6 M. Furthermore, benefiting from their good water solubility and biocompatibility, cell imaging and real-time monitoring of Cr3+ in living HepG2 cells were successfully achieved. L was synthesized. Cell imaging of HeLG2 cells labeled with the as-prepared L– Cr 3+ revealed the potential applications as a biological probe. A novel of coumarin derivatives isatin-3-(7′-Methoxychromone-3′-methylidene) hydrazone (L) were synthesized to detect Cr3+. Cell imaging of HeLG2 cells labeled with the as-prepared L revealed the potential applications as a biological probe. [Display omitted] • The novel L was synthesized based on coumarin schiff-base conjugate. • L– Cr3+ shown obvious fluorescence change. • Imaging strained with L– Cr3+ confirmed that it could be to detect HepG2 cells. [ABSTRACT FROM AUTHOR]

• A novel benzothiazole derivative BP was prepared for the relay quantification of Fe3+ and PPi. • Chemosensor BP displayed highly selective fluorescence "ON-OFF-ON" response to Fe3+ and PPi. • This chemosensor BP was applied to living cells imaging. A novel on-off-on fluorescence chemosensor BP based on benzothiazole for the relay recognition of Fe3+ and PPi was designed and synthesized. The chemosensor BP exhibited a high affinity to Fe3+ in the presence of other competing cations. The resultant BP -Fe3+ showed excellent recognition ability for PPi via Fe3+ displacement approach. The detection limits of BP for Fe3+ and BP -Fe3+ for PPi were estimated to be 2.59 × 10−8 M and 8.47 × 10−8 M, respectively. The low cytotoxicity and good cell-membrane permeability of BP and BP -Fe3+ complex makes them capable of Fe3+ and PPi imaging in living Hep G2 cells. [ABSTRACT FROM AUTHOR]

A turn-on fluorescent probe (Naphsulf-O) for hydrazine was developed by protecting the hydroxy group of the fluorophore 6-acetyl-2-hydroxynaphthalene via O-4-nitrobenzenesulfonylation, where 4-nitrobenzene was used as a fluorescence quenching moiety as well as an electrophile. Upon nucleophilic aromatic substitution (NAS) reaction of hydrazine toward the probe, the protecting group was removed and fluorophore was released. The probe exhibits a large Stokes shift, excellent selectivity and high sensitivity for hydrazine detection in aqueous solution with a detection limit of 0.716 ppb (22 nM), which is of great importance in both environmental and biological system. Furthermore, it was successfully applied to imaging of hydrazine in living cells. [ABSTRACT FROM AUTHOR]

Fluorescence probes have shown great potential in lipid droplets (LDs) imaging, whereas the imaging performance of the present commercial dyes is far from ideal. In addition, there still is lack of an effective strategy for designing LDs specific probes with satisfactory imaging performance. In this work, we have provided a novel method and probes based on donor (D)-acceptor (A) structure with nitrobenzoxadiazole (NBD) as the A unit and benzene derivatives as the D units, which are expected to show strong emission in lipid environment. Four probes (N–B , N–MeB , N–MeOB and N–Me 2 NB) with increasing electron-donating ability were prepared, whose fluorescence-emission changed from aggregation-induced emission (AIE) (N–B and N–MeB) to aggregation-caused quenching (ACQ) (N–MeOB and N–Me 2 NB). Intriguingly, the emission of these probes in oil changed from blue region to red (652 nm) with the increase of electron-donating ability from N–B to N–Me 2 NB , indicating the great emission regulable ability of this strategy. Moreover, these probes could specifically stain the intracellular and tissular LDs, which had shown considerable performance in the studying of LDs spatial distributions in mice and human atherosclerosis plaques. Impressively, N–Me 2 NB with the strongest electron-donating group of N-dimethylaniline showed negligible emission in aqueous solution but remarkable enhanced emission in oil, which could still efficiently stain the intracellular LDs at 200 nM. This novel construction strategy would provide new ideas for preparation of LDs specific probes. • A novel strategy for designing lipid droplets (LDs) specific probe was provided. • The fluorescence emission of N–MeOB and N–Me 2 NB were significantly enhanced in lipid environment. • N–MeOB and N–Me 2 NB showed great LDs imaging performance in cells. • N–MeOB and N–Me 2 NB can detect the LDs distribution in mice and human atherosclerosis plaques. [ABSTRACT FROM AUTHOR]

A new fluorescein-based fluorescent probe for the detection of Au 3+ has been developed. This probe was derived from 4′,5′-fluoresceindicarboxaldehyde and exhibited highly selective and sensitive response toward gold(III) ions in aqueous solution. There is a good linear relationship between the fluorescence intensity at 523 nm and the concentrations of Au 3+ ranging from 0 μM to 60 μM, which makes it effective for the detection of Au 3+ . The limit of detection (LOD) was evaluated to be 0.07 μM based on S/N = 3. The fluorescence enhancement was attributed to the irreversible C N bond hydrolysis that occurred to this probe in the presence of Au 3+ , generating the fluorescent 4′,5′-fluoresceindicarboxaldehyde. Furthermore, the imaging experiments indicated that this probe is cell-permeable and can be used to detect Au 3+ within living cell. [ABSTRACT FROM AUTHOR]

In this study, t Q[14] based AIE supramolecular network polymers were first constructed through the host-guest interaction between t Q[14] and tetrakis[4-(1-methylpyridin-4-yl) phenyl]ethene iodide (TPE-4P), which display excellent fluorescence properties due to AIE (aggregation-induced emission) effect. T Q[14] is tightly bonded to the methyl-pyridine part of TPE-4P to induce RIR (restricted intramolecular rotation), further triggering the AIE effect. The constructed supramolecular network polymer illustrates good biocompatibility in cell imaging for cytoplasmic HeLa cells and sensitively and selectively detected Fe3+ in an aqueous solution. This polymer has also been successfully applied to detect Fe3+ ions in live HeLa cells, especially to differentiate normal and iron-overloaded cells. Overall, this study broadens the application of t Q[14] in supramolecular chemistry and provides a new direction for t Q[14] in biological research. • This article are the first to use t Q[14], a unique and rare macrocyclic host, to construct a loosely cross-linked network AIE supramolecular polymers through the host-guest interaction between t Q[14]and tetrakis[4-(1-methylpyridin-4-yl) phenyl]ethene iodide (TPE-4P), which display excellent fluorescence properties due to AIE (aggregation-induced emission) effect. • The constructed supramolecular network polymer(TPE-4P@ t Q[14]) illustrates good biocompatibility in cell imaging for cytoplasmic HeLa cells and sensitively and selectively detected Fe3+ in an aqueous solution. • This supramolecular network polymer(TPE-4P@ t Q[14]) has also been successfully applied to detect Fe3+ ions in live HeLa cells, especially to differentiate normal and iron-overloaded cells. • This study broadens the application of t Q[14] in supramolecular chemistry and provides a new direction for t Q[14] in biological research. [ABSTRACT FROM AUTHOR]

Highlights: [•] The commercially available compounds act as selective sensor for Cu2+ ions. [•] S1 with Cu2+ ions show fluorescent turn-off by the paramagnetic effect. [•] S2 and S3 with Cu2+ ions show fluorescent turn-on due to the PET mechanism. [•] Sensors (S1–S3) detect Cu2+ ions in aqueous solution at nanomolar levels. [Copyright &y& Elsevier]

• F, N-dopped carbon dots and silica nanocomposites (F, NCDs@SiO 2) were synthesized. • F, NCDs@SiO 2 exhibits special visible-light excitable TADF in aqueous solution. • Fluorine doping can narrow the energy gap between T 1 and S 1 and promote the RISC. • Time-resolved cell imaging and anti-counterfeiting were realized by F, NCDs@SiO 2. Visible light has better biocompatibility and is more accessible for anti-counterfeiting compared to UV light. However, the synthesis of visible light excitable CDs-based long afterglow materials is still a challenge, especially in aqueous solution. Herein, we provide the first example of visible-light excitable thermally activated delayed fluorescence (TADF) in aqueous solution by confining the fluorine and nitrogen co-doped CDs in silica nanoparticles (F, NCDs@SiO 2). The hydrogen network and covalent bonds effectively protect the triplet excitons from quenching by water oxygen, so the nanoparticles can produce long-lived TADF in aqueous solutions under the excitation of white light. Meanwhile, the large number of silanol groups on the surface of amorphous silicon endows F, NCDs@SiO 2 with water solubility making them possible for time-resolved probes. We reveal that fluorine doping is essential for obtaining visible-light excitable TADF, which redshifts the excitation spectra and narrows the energy level between the singlet and triplet states through strong electron-withdrawing effect and heavy-atom effects. Our work provides a new strategy for the development of visible-light-excited TADF materials in aqueous solution and potential applications of CDs in information encryption, temperature sensor and time-resolved fluorescence bioimaging. [ABSTRACT FROM AUTHOR]

A novel single-component fluorescent probe using N -acetylgalactosamine as the hepatocyte-specific moiety and 3-nitrophthalimide as the fluorescent reactive unit was designed and synthesized for specifically detecting hepatocellular carbon monoxide in the liver of zebrafish in situ during acute liver injury. [Display omitted] • A novel one-component hepatocyte-specific fluorescent probe (HCP) was designed and successfully synthesized. • HCP exhibited a fast and high degree of fluorescence response to trace CO in solutions. • HCP could selectively visualize the endogenous CO in HepG2 cells over other cells. • HCP could be used to image hepatocellular endogenous CO release in the liver of zebrafish in situ during acute liver injury. A novel single-component fluorescent probe HCP using N -acetylgalactosamine (GalNAc) as the hepatocyte-specific moiety and 3-nitrophthalimide as the fluorescent reactive unit was designed and synthesized to specifically detect hepatocellular carbon monoxide (CO) in vitro and in vivo. The spectral experimental results indicate that HCP displayed high selectivity to CO and could be used to detect trace CO in an aqueous solution with a prominent fluorescent response (more than 80 times). Bioimaging results show that HCP could specifically transport to asialoglycoprotein receptor overexpressed HepG2 cells and could image endogenous CO release in HepG2 cells and the liver of zebrafish in situ during acute liver injury. [ABSTRACT FROM AUTHOR]

New strategies still need to be proposed that can be used to sense and remove toxic environmental pollutants in a sensing system. In this research, a novel NIR fluorescence sensor 1 was designed and prepared with aggregation induced emission (AIE) property. The fluorescence intensity of the sensor 1 in DMSO/H 2 O mixed solvent was changed along with the proportion of water. The sensor 1 can be successfully used for real-time detection and removal of Hg2+ in 20% DMSO aqueous solution with high selectivity, quick response and so on. Furthermore it can be efficiently reused and recycled without any loss through Na 2 S. In addition, the sensor 1 displayed high sensitivity and selectivity to cyanide ions in 1% DMSO aqueous solution with the presence of other interference anions. The sensing mechanism for Hg2+ and cyanide ion was evaluated by 1H NMR spectra, Mass spectrometry. The sensor 1 exhibited low cytotoxicity for biological applications, which was used as an outstanding fluorescent transducer for detection of cyanide ion in living cells. Based on the visible fluorescence change for the sensor 1 to cyanide ion, the measurement was performed for food materials containing cyanide, such as potato, cassava powder and almond. This research provides perspective potential in solving the problem of other pollution and stimulating new thinking for designing of the novel fluorescence materials. Unlabelled Image • A novel NIR sensor based triphenylamine was designed and synthesized with AIE effect. • The sensor successfully was used for detection Hg2+ and CN− with high selectively and sensitively. • The sensor was successfully applied to detection of Hg2+ and CN− in real samples and live cell imaging. [ABSTRACT FROM AUTHOR]

A cholesterol conjugated fluorescence probe T was designed and synthesized. The probe T can be used for recognition of Cu2+ by the absorption spectrum, fluorescence spectrum, and naked eyes respectively in aqueous solution. The cell imaging experiments showed that the probe has good membrane permeability and a huge potentiality for the detection of Cu2+ in living cells. Image 1 • A novel cholesterol conjugated fluorescence probe T was designed and synthesized. • The probe T exhibited a selective and sensitive response to Cu2+ in aqueous solution. • The cell imaging exhibited that the probe has huge potentiality for the detection of Cu2+ in living cells. [ABSTRACT FROM AUTHOR]

• A novel isatin-based Schiff base derivative L was prepared for the relay quantification of Fe3+ and PPi. • Chemosensor L displayed highly selective fluorescence "ON-OFF-ON" response to Fe3+ and PPi. • This chemosensor L was applied to living cells imaging. In this paper, we have designed and synthesized a novel isatin-based Schiff base derivative L as a fluorescence probe for the relay recognition of Fe3+ and PPi in aqueous and live cells. L exhibited a highly selective and sensitive fluorescence quenching for Fe3+ ions through a 1:1 stoichiometry. The decomplexation of L -Fe3+ by PPi led to the liberation of the fluorescent ligand L and thus the fluorescence was switched on. The detection limits of L for Fe3+ and L -Fe3+ for PPi were estimated to be 1.37 × 10−8 M and 4.21 × 10−8 M, respectively. The low cytotoxicity and good cell-membrane permeability of L and L -Fe3+ complex makes them capable of Fe3+ and PPi imaging in living Hep G2 cells. [ABSTRACT FROM AUTHOR]