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Eutrophication of water bodies is a phenomenon during which toxic microcystins from cyanobacteria are released into water. Natural minerals in soils and sediments are able to catalyze the degradation of microcystins. Here we studied the hydrolytic removal of microcystins on the surface of pyrite (FeS2). The surface structure of pyrite was analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and Fourier transformed infrared. The surface acidity of pyrite was measured by in situ diffuse reflectance infrared Fourier transform spectroscopy during pyridine adsorption/desorption. The concentration of d-alanine, d-glutamic acid, l-arginine and l-leucine were determined in pyrite/microcystin aqueous solution by high-performance liquid chromatography. Hydrolysis at the pyrite–microcystin interface was monitored by attenuated total reflection Fourier transformed infrared spectroscopy. Results show that sulfion and iron are layered, wherein the sulfion is above the surface, which provides active sites for the hydrolysis of microcystins. The hydrolysis rate of microcystins was up to 100% at 60 °C after 24 h in the presence of pyrite, based on the yield of l-arginine. Surface Lewis (≡Fe) and Bronsted acid (≡SH) sites of pyrite possibly bond to the carbonyl oxygen of peptide bonds, leading to highly efficient hydrolysis of microcystins.

CO-releasing molecule-3 (CORM-3) has been widely used recently as a convenient and safe CO donor to release exogenous CO in living cells and to study the effects of CO on cellular systems. Accordingly, development of effective methods for detecting and tracking CORM-3 in living systems is of great significance. In this work, a readily available fluorescent probe for detection of CORM-3 was reported for the first time. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye phthalimide and uses the reducing ability of CORM-3 to convert a nitro group to an amino group, and more importantly, it can be used for rapid, highly selective, and sensitive detection of CORM-3 with a distinct turn-on green fluorescence change in aqueous solution, living cells, and animals, thus providing a useful tool for studying CORM-3 in living systems.

Peroxynitrite (ONOO−) is one of the most important reactive oxygen species (ROS) in living systems and its subcellular detection is very important. In this research, a lysosome-targetable fluorescent probe for detection of exogenous and endogenous peroxynitrite in living systems was developed. This probe exhibits not only fast (25 s), highly sensitive (detection limit = 16 nM), and highly selective red to near-infrared fluorescent turn-on responses for ONOO− in the solution, but also excellent imaging ability for ONOO− in living cells and animals with low cytotoxicity. Moreover, this probe is lysosome-targetable and can be used for imaging lysosomal ONOO− in living cells. Overall, this work provides a new powerful fluorescent turn-on probe for detection of lysosomal peroxynitrite in living systems.

In this work, an ultrasensitive fluorescent turn-on probe (HBT-Phos) for rapid detection of the highly toxic phosgene is reported. This probe uses 2-(2′-hydroxyphenyl)benzothiazole (HBT), a well-known excited-state intramolecular proton transfer (ESIPT) dye as the fluorophore and an oxime moiety as the reaction site. Upon addition of various analytes, this probe specifically reacts with phosgene to release a highly fluorescent nitrile product (HBT-CN) via a dehydration process, which provides a new selective and ultrasensitive fluorescent turn-on detection method for phosgene (F/F0 ∼1750-fold, detection limit ∼0.48 nM in solution). Furthermore, using the aggregation-induced emission (AIE) of the product in solid state, this probe was successfully applied to prepare a silica plate-based portable sensing system for detecting phosgene gas in air with a detection limit as low as ∼0.34 ppm. All the results indicate that this probe is of great value for on-site detection of phosgene.

We report herein a new dicyanoisophorone-based colorimetric and near-infrared (NIR) fluorescent probe for rapid detection of thiophenols. This probe possesses a remarkable large Stokes shift (208 nm) and works in almost pure aqueous solution under mild conditions. More importantly, it displays a rapid, highly selective and sensitive dual colorimetric and NIR fluorescent turn-on signal responses for thiophenols and allows the detection of thiophenols in the presence of analytes including amino acids, biothiols and aliphatic thiols. Moreover, the fluorescence of this probe at 655 nm displays a good linear relationship with the thiophenol concentration ranging from 0 to 20 μM, and the detection limit is as low as 12 nM. Furthermore, the practicability of this new probe has been successfully proved by detection of thiophenol in real water samples and bioimaging of thiophenol in living cells.

The detection of pyrophosphate (PPi) in living systems has attracted considerable attention in recent years due to its biological significance. While many fluorescent PPi sensors were developed with emission changes in the visible region, near-infrared (NIR) fluorescent sensors for PPi are rather scarce. In this paper, a dicyanomethylene-benzopyran (DCMB) based phenol-bridged dinuclear Zn(II)-DPA (DPA: dipicolylamine) complex was prepared, which was found to be a promising NIR fluorescent sensor for PPi. This sensor features a remarkable large Stokes shift (>150 nm) and shows colorimetric and NIR fluorescence changes for PPi with high selectivity and sensitivity in 100% aqueous solution. The detection limit of this sensor for PPi was determined to be as low as 42 nM. In addition, this sensor exhibits low cytotoxicity and can be conveniently employed for bioimaging PPi in living cells and animals, indicating it has great potential for in vitro and in vivo detection of PPi.

In this paper, a new colorimetric and ratiometric fluorescent probe for the rapid detection of phosgene is reported. This probe is based on a readily prepared and highly fluorescent iminocoumarin, which reacts rapidly with phosgene to form a cyclic carbamate product to produce, distinctive colorimetric and ratiometric fluorescent signal changes. The detection of phosgene with this probe is fast (complete within 2 min), highly selective and sensitive with a detection limit of 27 nM in solution. Moreover, this probe can be used to prepare easy-to-use paper test strips for convenient visual and fluorescent detection of phosgene gas even at a concentration of 0.1 mg/L. Overall, this work provides a very promising dual colorimetric and ratiometric fluorescent probe for rapid and sensitive detection of phosgene both in solution and in the gas phase.

The detection of hydrogen sulfide (H2S) in living systems has received considerable attention in recent years. Although many probes have been reported for detection of cellular H2S, the creation of rapid, highly selective and sensitive near-infrared (NIR) probe for in vivo detection of H2S still remains a challenging target. Herein, a novel dicyanoisophorone-based NIR fluorescent turn-on probe for H2S was reported. This probe uses a sulfonamide group for the first time as a selective reaction site for H2S and more importantly, it displays a rapid ( 130-fold) with a remarkable large Stokes shift (221 nm). Moreover, it has low cytotoxicity and can be used for tracking and imaging of H2S in living cells and animals. Overall, this work provided a very promising NIR fluorescent probe with a new reaction site and excellent sensing properties for rapid detection of H2S both in vitro and in vivo.

In this work, a new colorimetric and far-red to near-infrared fluorescent turn-on probe for rapid detection of palladium was reported. This probe uses a readily available seminaphthorhodafluor dye as the fluorophore and an allylcarbonate moiety as the reaction site. Based on the Pd0-triggered cleavage reaction, this probe shows rapid (within 2 min), selective, and sensitive response for palladium with different oxidation states (Pd0, or Pd2+ and Pd4+ in the presence of PPh3) in almost wholly aqueous solution under mild conditions, accompanied by distinct color changes and significant fluorescent turn-on signal in the far-red to near-infrared region. The detection limit of this probe for Pd0 was determined to be as low as 1.6 nM in solution. In addition, a sensitive bioimaging of palladiun in living cells can be achieved with a low level of this probe (2 μM), indicating the new developed probe has great potential for palladium detection in both solution and living systems.

In this paper, a new colorimetric and ratiometric fluorescent probe was developed for rapid detection of palladium in aqueous solution under mild conditions. This probe is based on a novel phthalimide-rhodol dyad, which has a unique ESIPT-FRET mechanism to give the desired ratiometric fluorescent signal changes. Optical sensing studies showed that this probe not only has high selectivity and sensitivity for palladium with a low detection limit of 31 nM, but also exhibits rapid and distinct colorimetric and ratiometric fluorescent signal changes with a large pseudo Stokes shift. In addition, the probe was successfully used for fluorescent imaging of palladium in living cells. Overall, this work provided a new ESIPT-FRET platform for development of ratiometric probes and a new attractive colorimetric and ratiometric fluorescent probe for detection of palladium.

Since carbon monoxide (CO) was recognized as an important gasotransmitter, great interest has been given to develop probes for detection of this gas molecule in living systems. While several fluorescent probes have been developed very recently for imaging CO in living cells, probes for in vivo detection of CO have not yet been reported. Herein, we report a new NIR fluorescent CO probe that can be used for detection of CO both in vitro and in vivo. This probe works in almost wholly aqueous solution under mild conditions and shows high selectivity and sensitivity for CO in the presence of Pd 2+ , giving rapid (within few minutes) and distinct colorimetric and near-infrared (NIR) fluorescent turn-on signal changes with a detection limit as low as 3.2 nM. Moreover, we also show that this probe has low cytotoxicity and can be conveniently used to image CO in both living cells and animals.

Selenocysteine (Sec) is known as the 21st amino acid that is incorporated into selenoproteins (SePs) and plays vital roles in living systems. Accordingly, development of fluorescent detection method for Sec is of significance. Herein, a readily available fluorescent Sec probe is reported. Although this probe has been reported before for detection of biothiols, the studies in this work show that it can be used for rapid, high selective and sensitive detection of Sec over biothiols and many other analytes with dual colorimetric and fluorescent turn-on signal changes simply by slightly changing the detection conditions. The detection limit of this probe for Sec was found to be about 47 nM with a wide linear range (0–80 μM). In addition, this probe has low cytotoxicity and is able to detect Sec in serum samples and in living cells, indicating it can be used as a potential new molecular tool for Sec detection.

Carbon monoxide (CO), a highly toxic gas, is now well known as an important gasotransmitter in living systems. Accordingly, development of fluorescent probes for CO is of great significance. However, fluorescent detection of CO in living systems is challenging due to the lack of effective probes, and particularly, ratiometric fluorescent probes for CO have not yet been reported. In this article, a readily available colorimetric and ratiometric fluorescent probe system for CO was reported. This probe system shows excellent sensing properties for CO including rapid response, high selectivity and sensitivity with a low detection limit (58 nM), and capable of giving distinct colorimetric and ratiometric fluorescent signal changes for CO in aqueous solution under mild conditions. In addition, this probe system has low cytotoxicity and can be used to ratiometrically detect CO in living cells. Furthermore, a very convenient paper test strip system can be developed with this probe for visual detection of CO gas. Overall, this work provided a very promising probe for colorimetric and ratiometric fluorescent detection of CO in air, aqueous solution, and living cells.

Ratiometric near-infrared (NIR) fluorescent probes are attractive tools for bioimaging applications. Although many fluorescent probes have been developed for detection of the biologically important cysteine (Cys), ratiometric NIR fluorescent probes for Cys are very rare, particularly those with significant fluorescence enhancement in the NIR region. In this work, a new ratiometric NIR fluorescent probe with significant NIR fluorescent turn-on changes was reported for rapid, colorimetric and ratiometric fluorescent detection of Cys. This probe is able to detect Cys in aqueous solution under mild conditions, with high selectivity and sensitivity for Cys over various analytes including the similar structured homocysteine (Hcy) and glutathione (GSH). The detection limit of this probe for Cys was found to be as low as 0.2 μM, which is far below the normal content of Cys (30–200 μM) in cells. Besides the excellent sensing properties, this probe shows low cytotoxicity and can be conveniently applied to image intracellular Cys in living cells, indicating it is a promising tool for biological applications.

Haptens 2-Methyl-4-(trifluoromethyl)thiazole-5-carboxylic acid and 2,6-Dibromo-4-(trifluoromethoxy)aniline, the two moieties of thifluzamide, were conjugated with carrier proteins for the synthesis of artificial antigens. Two distinct anti-thifluzamide polyclonal antibodies (PAb-1 and PAb-2) were produced from the immunized female Balb/c mice. The indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) in two formats based on the PAbs was developed for thifluzamide analysis. The concentration of 50% inhibition (IC50) of ELISA-1 was 1.39 mg L−1 and its limit of detection (LOD) was 0.082 mg L−1. Meanwhile, ELISA-2 had a similar IC50 of 1.96 mg L−1 and a LOD of 0.074 mg L−1 as ELISA-1. Both the raised PAbs exhibited high specificity to thifluzamide. The recoveries for spiked samples including water and wheat ranged from 72.0% to 128.4%, and the accuracy of ELISA was confirmed by high-performance liquid chromatography. In summary, the ic-ELISA might be a promising tool for simple, sensitive and rapid detection of thifluzamide residues in real samples.

A novel aza-coumarin-hemicyanine conjugated hybrid was prepared, which was found to be a promising colorimetric and ratiometric near-infrared (NIR) fluorescent probe for detection of bisulfite/sulfite in aqueous solution. This probe shows a rapid response (within 30 s) and high selectivity and sensitivity for bisulfite/sulfite, giving distinct colorimetric and ratiometric fluorescence changes at 717 and 560 nm. The detection limit for bisulfite was estimated to be 87 nM. In addition, detection of bisulfite in food samples and bioimaging of both exogenous and endogenous bisulfite in living cells with this probe were successfully applied, which indicates that this probe holds great potential for bisulfite detection both in real samples and in living cells.

A new simple and readily available fluorescent probe for cysteine (Cys) was reported. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye and uses two acrylate moieties as the Cys reaction sites to promote signal changes. Importantly, this probe shows rapid fluorescent turn-on signal changes for Cys with high selectivity and sensitivity over various analytes including the similar structured homocysteine (Hcy) and glutathione (GSH) in aqueous solution under mild conditions. The detection limit of this probe for Cys was found to be as low as 0.80 μM, which is far below the normal content of Cys (30–200 μM) in cells. This probe was also successfully applied for bioimaging of intracellular Cys in living cells with low cytotoxicity. Besides, a paper test strip system was developed with this probe for a convenient detection of Cys.

Carbon monoxide (CO) is an important gasotransmitter in living systems. The biological detection of this gasotransmitter is still in its infancy and urgently needs probes. In this paper, a novel fluorescent probe system, which is based on the Pd 0 -mediated Tsuji–Trost reaction, is reported for rapid detection of CO both in in vitro and in living cells. This probe system is readily available and shows excellent sensing properties for CO including rapid and distinct colorimetric and fluorescent turn-on responses, high selectivity and sensitivity with a low detection limit (25 nM) in aqueous solution under mild conditions. In addition, fluorescent imaging of CO in living cells can be conveniently achieved by a low dose of this probe system.

Recently, the fluorescent detection of carbon monoxide (CO) in living cells has attracted great attention. However, due to the lack of effective ways to construct fluorescent CO probes, fluorescent detection of CO in living cells is still in its infancy. In this paper, we report for the first time the use of allyl ether as a reaction site for construction of fluorescent CO probes. By this way, two readily available allyl fluorescein ethers were prepared, which were found to be highly selective and sensitive probes for CO in the presence of PdCl2. These probes have the merits of good stability, good water-solubility, and rapid and distinct colorimetric and remarkable fluorescent turn-on signal changes. Moreover, a very low dose of these two probes can be used to detect and track CO in living cells, indicating that these two probes could be very promising biological tools for CO detection in living systems. Overall, this work provided not only two new promising fluorescent CO probes but also a new way to de...

Since the biological significance of hydrogen sulfide (H 2 S) has been disclosed recently, great attention has been given to the development of efficient and selective fluorescent probes for H 2 S over other biothiols. Herein, we report that combining an aldehyde group with thiolysis of nitrobenzofurazan (NBD) ether can be used as a new approach to develop such kind of probes for H 2 S. Using this approach, two new fluorescent H 2 S probes were developed, and both of them can be used for rapid capture and visualization of H 2 S with excellent sensing properties including good water solubility, high selectivity and sensitivity, and distinct colorimetric and fluorescent turn-on responses. More importantly, these two probes are able to detect H 2 S in the presence of other biothiols. In addition, we also demonstrated that one probe can be used for fluorescent imaging of H 2 S in living cells with low cytotoxicity.

The first visible-light-triggered metal-free and ratiometric fluorescent CORM is reported. This CORM can be used to release CO with distinct ratiometric fluorescence changes in aqueous solution, living cells, zebrafish, and mice, which provided an excellent controllable and trackable CORM for living systems.

Carbon monoxide (CO) is an important gasotransmitter in living systems and its fluorescent detection is of particular interest. However, fluorescent detection of CO in living cells is still challenging due to lack of effective probes. In this paper, a readily available fluorescein-based fluorescent probe was developed for rapid detection of CO. This probe can be used to detect CO in almost wholly aqueous solution under mild conditions and shows high selectivity and sensitivity for CO with colorimetric and remarkable fluorescent turn-on signal changes. The detection limit of this probe for CO is as low as 37 nM with a linear range of 0-30 μM. More importantly, this probe (1 μM dose) can be conveniently used for fluorescent imaging CO in living cells.

This is the first report on ligand-assisted assembly of BiOBr. BiOBr, using cetylpyridinium bromide (CPB) as Br source and surface template, was prepared with water with the presence of three polyhydroxyl alcohols. Based on SEM, HR-TEM and XRD, mannitol results in different particle morphologies. Rather than smooth microspheres, projections form that double surface area. BiOBr prepared in mannitol displayed the highest photocatalytic activity and tripled the oxygen consumption rate compared to the other preparations. The Bi 3 + –mannitol complex competes with hydroxide for Bi 3 + in the CPB micelles and limits the availability of BiO + , altering the assembly process. A four-step mechanism for ligand-assisted assembly of BiOBr in mannitol is proposed.

The detection of hydrazine is of particular interest given its toxicity and high levels of use. In this paper, a new fluorescent probe was developed for rapid detection of hydrazine. This probe is chemically masked with a 2-fluoro-5-nitro-benzoic ester motif as a new reaction site for hydrazine. More importantly, unlike most probes for hydrazine in the literature that need to use high levels of organic solvents, this probe displays a fast colorimetric and fluorescent turn-on response for hydrazine with high selectivity and sensitivity in almost wholly water solution under mild conditions. The detection limit of this probe for hydrazine is about 0.10 μM (∼3 ppb) with a linear range of 0–20 μM. Further investigation showed that this probe could be used to develop an easy-to-prepare and easy-to-detect paper test strip for cheap and effective visual detection of hydrazine. In addition, this probe can be used to image hydrazine in living cells.

Detection and imaging of peroxynitrite (ONOO−) in living systems has attracted considerable attention in recent years due to its biological significance. In this paper, a new highly selective and sensitive near-infrared (NIR) fluorescent turn-on probe for ONOO− was developed. This probe uses a dicyanoisophorone-based fluorescent dye as the fluorophore and α-ketoamide as the reaction site. In the presence of ONOO−, the probe exhibits notable fluorescence enhancement at 660 nm with rapid response (

Selenocysteine (Sec) is the 21st naturally occurring amino acid and has emerged as an important sensing target in recent years. However, fluorescent detection of Sec in living systems is challenging. To date, very few fluorescent Sec probes have been reported and most of them respond fluorescence to Sec in the visible region. In this paper, a very promising near-infrared fluorescent probe for Sec was developed. This probe works in aqueous solution over a wide pH range under mild conditions and can be used for rapid, highly selective and sensitive detection of Sec with significant near-infrared fluorescent turn-on signal changes. In addition, it features a remarkable large Stokes shift (192 nm) and a low detection limit (60 nM) for Sec with a wide linear range (0–70 μM). Moreover, this probe can be conveniently used to detect Sec in serum samples, living cells, and animals, indicating it holds great promise for biological applications.

Selenocysteine (Sec) has emerged as an important sensing target in recent years. In this paper, a colorimetric and near-infrared fluorescent turn-on probe for Sec was developed. This probe features a remarkable large Stokes shift (146nm) and shows a rapid, highly selective detection process for Sec with obvious colorimetric and near-infrared fluorescent (Em 706nm with Ex 560nm) turn-on responses. In addition, this probe can be used to quantitatively detect Sec with high sensitivity with a detection limit of 62nM over a wide linear range (0.2-80μM). Moreover, it was further demonstrated that this NIR fluorescent probe can be employed to image both exogenous and endogenous Sec in living cells, indicating that this probe has great potential for biological applications.