Search

Mercury (Hg) is a heavy metal with high toxicity and easy migration; it can be enriched through the food chain, and cause serious threats to the natural environment and human health. So, the development of a method that can be used to detect mercury ions (Hg2+ ) in the environment, in cells, and in organisms is very important. Here, a new 7-hydroxycoumarin-derived carbonothioate-based probe (CC-Hg) was designed and synthesized for detection of Hg2+ . After addition of Hg2+ , a large fluorescence enhancement was observed due to the formation of 7-hydroxyl, which reinforced the intramolecular charge transfer process. The CC-Hg probe had good water solubility and selectivity. Moreover, the probe was able to detect Hg2+ quantitatively over the concentration range 0-2 μM and with a detection limit of 7.9 nM. Importantly, we successfully applied the probe to detect Hg2+ in water samples, in living cells, and in zebrafish. The experimental results demonstrated its potential value in practical applications.

Hepatitis B virus (HBV) is a widespread blood-borne pathogen associated with the complication of liver cirrhosis and hepatocellular carcinoma, particularly in south-east Asian and African countries where HBV is highly endemic and the budget and resources are limited. Therefore, simple, rapid, and portable field detection methods are crucial to efficiently control HBV infection. In this study, using heat-treated DNA, we developed two-field applicable detection assays for HBV based on recombinase-aided amplification (RAA). One was an internal controlled duplex RAA assay using a portable real-time fluorescence detection device, another was an instrument-free visual observation assay using lateral flow dipsticks. The entire experimental time was greatly shortened to less than 40 minutes at 39.0°C. The sensitivities, specificities, and clinical performance of both assays were evaluated. Compared with quantitative polymerase chain reaction assay as a reference, our results demonstrated that the two RAA-based assay obtained 97.18% and 95.77% of sensitivity, respectively, and the specificity was 100%, by testing a total of 157 serum samples with HBsAg positive. We conclude that the advantages of rapidity, simplicity, portability, and visualization of proposed two assays make them great potentials in point-of-care testing of HBV infection by untrained people in resource-limited situations.

Peroxynitrite (ONOO

Mercury ions as high toxic pollutants have received wide-spread attention because of their poisonousness, persistence and enrichment. To better understand the distribution of mercury species and supplement more detailed toxicological research, it is necessary to develop some methods for monitoring mercury ions with high sensitivity and selectivity. Therefore, a simple rhodol-based highly selective fluorescent probe, RH-Hg, has been developed for monitoring Hg2+ with thiocarbamate as the recognition receptor. The probe RH-Hg can quantificationally detect mercury ions in aqueous solution assisted by hydrogen peroxide (H2O2), and it can discriminate Hg2+ through "naked-eye" observation of the color changes from light orange to dark pink. Finally, the practical applications of the probe RH-Hg in the river water further demonstrated that it will be an effective and economical tool for monitoring the distribution of Hg2+ in the environment.

In this work, by taking full advantage of the transformation of nitro group into amino moiety under the direct reduction of CO, a new metal-free colorimetric and near-infrared fluorescent probe NIR-CO for rapid and specific tracing of intracellular CO has been constructed, and it also become the first reaction-based near-infrared fluorescent probe for CO detection without additional reagents. Probe NIR-CO could quantitatively detect CO at the nanomolar level and the detection limit was calculated as low as 6.1 nM. Additionally, probe NIR-CO with preeminent sensing properties was successfully applied to monitor the fluctuations of endogenous CO levels in living systems. In particular, the up-regulation of heme oxygenase-1 (HO-1) caused by transient glucose deprivation (TGD) in living cells and the down-regulation of HO-1 inhibited by high glucose (HG) in zebrafish were confirmed for the first time via mapping the glucose-induced fluctuations of CO levels. Thus, we anticipate that probe NIR-CO not only can serve as a powerful tool to investigate the detailed biological functions of CO in the pathophysiological processes, but also possesses potential applications of in situ monitoring HO-1 activity in the complex biological systems.

Cell-selective imaging of some biological species is significant for the diseases research of a specific tissue or organ. Peroxynitrite (ONOO−) as a kind of reactive nitrogen species (RNS), plays extremely important roles in diverse physiological and pathological processes. Developing cell-specific fluorescent probes for tracing ONOO− in living systems remains a great challenge due to the complexity of internal environment and high autofluorescence. In this work, we developed a galactose-appended hepatoma-specific fluorescent probe Gal-NHP with hydroxynaphthalimide as the fluorophore and hydroquinone moiety as the responsive receptor for sensitively detecting endogenous ONOO− in live HepG2 cells. Probe Gal-NHP could selectively trace ONOO− without interference from other species such as HOCl and H2O2. In addition, the introduction of galactose enhanced the water solubility of this probe, and Gal-NHP could respond quickly to ONOO− in aqueous solution. The quantitative experiment showed the excellent sensitivity of this probe with a good linear relationship. Above all, fluorescence imaging results displayed it possessed excellent hepatoma-specific ability and could successfully detect endogenous ONOO− of hepatoma cells in real time. Thus, this newly developed probe would benefit to reveal the roles of ONOO− in hepatoma cells.

It is very important to detect native hypochlorous acid (HOCl) in the complex biosystems owing to the important roles of HOCl in the immune defense and the pathogenesis of numerous diseases. In this paper, a new p-aminophenylether-based fluorescent probe PAPE-HA was developed for specific detection of HOCl. Probe PAPE-HA could implement the quantitative detection of HOCl ranging from 0 to 1 μM and the detection limit was obtained as low as 1.37 nM. Additionally, probe PAPE-HA could reach a rapid response for HOCl (2 min). Importantly, probe PAPE-HA with preeminent specificity and ultrasensitivity was proven to possess powerful capability of tracking native HOCl in live cells and zebrafish, and we thus anticipate that probe PAPE-HA could be used as a novel promising tool for revealing diverse cellular functions of HOCl.

In this work, taking full advantage of the intramolecular charge transfer (ICT) mechanism, a hydroxynaphthalimide-based ratiometric two-photon fluorescent probe RTP-PN was synthesized to detect ONOO−. Probe RTP-PN could accurately detect ONOO− in the range of 1.4 nM-1.4 μM with the detection limit of 1.4 nM by a ratiometric fluorescence spectroscopy method. Additionally, probe RTP-PN exhibited an ultrafast response for ONOO− than other various species including H2O2 and ClO−. Finally, probe RTP-PN was successfully adopted to detect intracellular ONOO− by the two-photon excitation microscopy.

A water-soluble fluorescent probe for monitoring thiophenols based on a GFP-type TPC-OH fluorophore and a 2,4-dinitrophenyl ether recognition unit was designed. This probe possessed remarkable sensitivity and specificity toward thiophenols in an almost pure aqueous solution, and also showed good interference immunity to other related analytes including aliphatic mercaptans. Meanwhile, the probe displayed a prominent linear correlation between the thiophenol concentrations in the range of 0 to 20 μM and the fluorescence intensities at 492 nm, and the detection limit was as low as 33 nM. More strikingly, probe 1 was employed to visualize thiophenol in both living cells and zebrafish, which further demonstrated that probe 1 was a powerful practical tool in monitoring thiophenols in living systems.

The detection of ionic mercury (Hg2+) is very important because it is a highly toxic environmental pollutant that could cause serious diseases and threaten human health. Herein, we designed a new carbonothioate-based far-red fluorescent probe, CBRB, with a seminaphthorhodafluor dye as the fluorophore for the detection of Hg2+. The CBRB probe by itself exhibited very weak fluorescence due to the enhanced photo-induced electron transfer (PET) effect and inhibited the intramolecular charge transfer (ICT) process caused by the carbonothioate moiety. Upon addition of Hg2+, a tremendous fluorescence enhancement was achieved, attributed to the removal of the carbonothioate group via a specific mercury-promoted desulfurization reaction. Moreover, the probe displayed a large Stokes shift (about 105 nm) and was used to quantitatively measure the concentration of Hg2+ for concentrations ranging from 0 to 1 μM (DL = 3.6 nM). In addition, CBRB in our experiments responded exclusively to Hg2+, even in the presence of high concentrations other ions. Gratifyingly, this probe was successfully used to monitor Hg2+ in environmental water samples and to image Hg2+ in living cells as well as in zebrafish.

The development of techniques for monitoring the gasotransmitter carbon monoxide (CO) at the subcellular level is significant for elucidating its diverse cellular functions. Herein, a mitochondria-targetable, colorimetric and far-red fluorescent probe FR-CO is presented for tracking CO levels in the mitochondria of living cells. The FR-CO probe can sensitively detect CO using a turn-on fluorescence spectroscopic method, with a detection limit of around 38.9 nM. Additionally, the FR-CO probe exhibits outstanding selectivity towards CO over other various bioactive molecules. Moreover, the obvious color change (from colorless to pink) of the probe makes it possible to visually detect CO in aqueous solution. Most importantly, the excellent response properties of the FR-CO probe enable its application in the tracking of fluctuations in the CO levels of mitochondria in living cells, and it is thus anticipated that this probe will be a novel tool for further investigating the biological functions of CO in subcellular mitochondria.

In this work, a simple dichlororesorufin-based colorimetric and fluorescent probe R-Hg with the recognition receptor of carbonothioate was designed, synthesized, and exploited to determine mercury ions in aqueous solution and living cells as well as in zebrafish. After a series of analytical tests, probe R-Hg showed some excellent characteristics, such as ultrasensitivity, high selectivity, and good water solubility. The probe solution exhibited a very large fluorescence enhancement (about 150-fold) upon addition of Hg2+. Additionally, probe R-Hg exhibited excellent sensitivity, which could quantificationally detect Hg2+ at the nanomolar level, and the detection limit was 0.49 nM. Moreover, probe R-Hg could be used as a “naked-eye” probe for monitoring Hg2+, because the color of its solution transformed remarkably from yellow into pink with the participation of Hg2+. Importantly, probe R-Hg has potential application value and has been successfully applied to the determination of Hg2+ in practical water sa...

A new rhodol-derived fluorescent probe 1 with picolinate as the recognition receptor was designed and simply synthesized using a one-step reaction. With the concentration of added Cu2+ increases, it gradually turns pink, so the effect of naked eye detection can be achieved. The detection limit of probe 1 for Cu2+ is 42 nM, and the linear detection range was 0-2 μM. The experimental results showed that 1 was a fluorescent probe with high selectivity, good water solubility, and high sensitivity to Cu2+ . Probe 1 was successfully applied in cell imaging experiments and can detect the concentration of Cu2+ in water samples. All these indicate that probe 1 has the potential to be applied to the detection of Cu2+ concentration in the real environment.

Mercury (Hg) is a heavy metal with high toxicity and easy migration; it can be enriched through the food chain, and cause serious threats to the natural environment and human health. So, the development of a method that can be used to detect mercury ions (Hg

Developing highly specific and ultrasensitive techniques for monitoring hypochlorous acid (HOCl) in the environment and living systems is very important to guarantee its safe use and disclose its diverse biological functions. We herein presented a simple water-soluble lysosome-targeted fluorescent probe TCRH for the detection of HOCl. Probe TCRH could sensitively monitor HOCl at the nanomolar levels with the detection limit of 0.12 nM. Additionally, probe TCRH with the response unit of thiocarbamate could selectively detect HOCl over other various analytes. Furthermore, probe TCRH showed an ultrafast response for HOCl (

Exploiting specific and sensitive techniques for tracking peroxynitrite (ONOO−) in the biological systems is of great significance to understand its diverse pathophysiology. Herein, we have constructed a simple, 4-hydroxynaphthalimide-derived two-photon fluorescent probe TPHQ for imaging ONOO− in live cells. Probe TPHQ with the recognition receptor of hydroquinone moiety exhibited excellent selectivity towards ONOO− over various bio-related analytes including H2O2 and OCl−. Additionally, probe TPHQ could rapidly monitor ONOO− with high sensitivity (DL = 16 nM). With probe TPHQ, the fluctuations of ONOO− levels in live cells were successfully tracked by the one-photon and two-photon fluorescence microscopy.

Highly specific and ultrasensitive fluorescent probes for tracking the intracellular native hypochlorous acid (HOCl) levels are urgently needed owing to its important molecular functions in the biological systems. In this contribution, a simple thiocarbamate-caged 7-hydroxycoumarin (TCHC) was developed as fluorescent probe for monitoring HOCl in live cells. Probe TCHC exhibited preeminent specificity towards HOCl over other various bioactive substances. Importantly, probe TCHC could sensitively detect HOCl in the range of 0–175 pM with the detection limit of 17 pM, which was attributed to the multiple fluorescence sensing mechanisms including photo-induced electron transfer (PET), intramolecular charge transfer (ICT), and the chlorination. Furthermore, probe TCHC displayed an instant response towards HOCl (

The development of highly specific and ultrasensitive fluorescent probes for tracking basal mitochondrial hypochlorite is very important to unravel its diverse cellular functions in the mitochondria of living cells. In this paper, we have developed a water-soluble, mitochondria-targeted near-infrared fluorescent probe NB-OCl for selectively measuring OCl- in the presence of higher concentration (500 μM) other biologically important substances. Surprisingly, the obtained results demonstrated that probe NB-OCl could sensitively determine OCl- in the range of 0-200 pM with the detection limit of 10.8 pM. To the best of our knowledge, NB-OCl is the first fluorescent probe for the specific determination of OCl- at the picomolar level. Moreover, probe NB-OCl exhibits a fast response for OCl- (< 5 s), which would be in favor of tracking the highly reactive and short-lived OCl- in the living systems. The preeminent recognition properties of probe NB-OCl enable its applications in the monitoring of basal OCl- and the fluctuations of endogenous/exogenous OCl- levels in the mitochondria of living cells.

Peroxynitrite (ONOO − ) is involved in various physiological and pathological processes. However the detailed mechanisms of ONOO − in the biological systems remain unclear, probably due to the lack of specific and sensitive methods for detecting ONOO − in living cells. Herein, based on the intramolecular charge transfer (ICT) mechanism, we have developed a highly specific and ultrasensitive ratiometric far-red fluorescent probe RFR-PN for monitoring ONOO − in living cells. Experimental results demonstrated probe RFR-PN possesses high specificity toward ONOO − than other various bioactive molecules. Probe RFR-PN could quantitatively and sensitively detect ONOO − with the detection limit of 0.9 nM by the ratiometric fluorescence method. Surprisingly, the fast response of probe RFR-PN for ONOO − ( − in the living systems. Moreover, probe RFR-PN was successfully applied to the fluorescence imaging of endogenous ONOO − in living cells.

The development of sensitive methods for imaging endogenous peroxynitrite (ONOO − ) in the mitochondria of living cells is very important to disclose its diverse physiological and pathological functions. In this paper, we have described a simple, mitochondria-targeted far-red fluorescent probe Mito-PN for selectively detecting ONOO − even though in the presence of higher concentration (1 mM) other biologically important substances. The experimental results indicated that probe Mito-PN could quantitatively determine ONOO − in the range of 0.5–8 μM with the detection limit of 17 nM. In addition, probe Mito-PN exhibits a fast response for ONOO − ( − in the biological systems. The excellent sensing properties of probe Mito-PN enable its applications in the tracking of the fluctuations of endogenous ONOO − levels in the mitochondria of living cells.

Developing some methods that can simply and effectively detect mercury ions (Hg2+) in the environment and biological systems are very important due to the problems of high toxicity and biological accumulation. Herein, we report a simple rhodol-derived colorimetric and fluorescent probe rhodol-Hg with a recognition receptor of carbonothioate for the specific determination of Hg2+. The color of probe rhodol-Hg solution changed remarkably from colorless to pink in the presence of Hg2+, thus rhodol-Hg could act as a "naked-eye" probe for Hg2+. Additionally, this probe exhibited high selectivity and ultrasensitivity in aqueous solution with the limit of detection (LOD) of 1.4 nM toward Hg2+, and the linear range was 0 - 0.8 μM determined by turn-on fluorescence spectrometry. Importantly, this probe has been successfully used for the detection of Hg2+ in environmental waters and living cells.

The development of techniques for detecting HOCl at the subcellular level is very important to elucidate its cellular functions. Due to its relatively low concentration, it is still a great challenge to specifically track the basal HOCl in normal cells. In this paper, based on the unique chlorination of HOCl by the initiation of chlorinium ions (Cl+) in an acidic medium, we have developed a simple pH-mediated lysosome-targetable fluorescent probe Lyso-HOCl for the specific detection of HOCl over other bioactive molecules at higher concentration (500 μM). Our results show that Lyso-HOCl possesses a detection limit of 8.0 pM, and can quantitatively detect HOCl at the picomolar level. The ultrasensitive and ultrafast response property of probe Lyso-HOCl offers a good opportunity to monitor the basal HOCl and the fluctuation of endogenous HOCl levels in the lysosomes of macrophages (Raw 264.7 cells), and we thus anticipate that this probe would provide a promising tool for further unraveling the biological functions of HOCl in subcellular lysosomes.

Mercury ions as high toxic pollutants have received wide-spread attention because of their poisonousness, persistence and enrichment. To better understand the distribution of mercury species and supplement more detailed toxicological research, it is necessary to develop some methods for monitoring mercury ions with high sensitivity and selectivity. Therefore, a simple rhodol-based highly selective fluorescent probe, RH-Hg, has been developed for monitoring Hg

Exploring techniques for monitoring the intracellular signaling molecule carbon monoxide (CO) in biosystems is important to help understand its various cellular functions. Therefore, a simple long-wavelength colorimetric fluorescent probe LW-CO was designed for selectively and sensitively detecting intracellular CO in living systems. Probe LW-CO is ultrasensitive and can track CO levels in the range of 0–1 μM, with a detection limit of about 3.2 nM. Additionally, the obvious color changes of probe LW-CO with CO (yellow to pink) provide a convenient way for on-site detection of CO with the naked eye. Probe LW-CO was applied to track the exogenous levels of CO in RAW264.7 cells. Probe LW-CO proved to be an efficient method for investigating various cellular functions of CO.

Background Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two main etiological agents of Hand, Foot and Mouth Disease (HFMD). Simple and rapid detection of EV71 and CA16 is critical in resource-limited settings. Methods Duplex real time reverse-transcription recombinase aided amplification (RT-RAA) assays incorporating competitive internal amplification controls (IAC) and visible RT-RAA assays combined with lateral flow strip (LFS) for detection of EV71 and CA16 were developed respectively. Duplex real time RT-RAA assays were performed at 42 °C within 30 min using a portable real-time fluorescence detector, while LFS RT-RAA assays were performed at 42 °C within 30 min in an incubator. Recombinant plasmids containing conserved VP1 genes were used to analyze the sensitivities of these two methods. A total of 445 clinical specimens from patients who were suspected of being infected with HFMD were used to evaluate the performance of the assays. Results The limit of detection (LoD) of the duplex real time RT-RAA for EV71 and CA16 was 47 copies and 38 copies per reaction, respectively. The LoD of the LFS RT-RAA for EV71 and CA16 were both 91 copies per reaction. There was no cross reactivity with other enteroviruses. Compared to reverse transcription-quantitative PCR (RT-qPCR), the clinical diagnostic sensitivities of the duplex real time RT-RAA assay were 92.3% for EV71 and 99.0% for CA16, and the clinical diagnostic specificities were 99.7 and 100%, respectively. The clinical diagnostic sensitivities of the LFS RT-RAA assay were 90.1% for EV71 and 94.9% for CA16, and the clinical diagnostic specificities were 99.7 and 100%, respectively. Conclusions The developed duplex real time RT-RAA and LFS RT-RAA assays for detection of EV71 and CA16 are potentially suitable in primary clinical settings.

Liver cancer is a kind of high mortality cancer due to the difficulty of early diagnosis. And according to the reports, the concentration of reactive oxygen species (ROS) was higher in cancer cells than normal cells. Therefore, developing an effective fluorescent probe for hepatoma-selective imaging of hypochlorous acid (HOCl) which is one of the vital ROS is of great importance for understanding the role of HOCl in liver cancer pathogenesis. However, the cell-selective fluorescent probe still remains a difficult task among current reports. Herein, a galactose-appended naphthalimide (Gal-NPA) with p-aminophenylether as a new receptor and galactose moiety as hepatoma targeting unit was synthesized and employed to detect endogenous HOCl in living HepG2 cells. This probe was proved to possess good water solubility and could respond specifically to HOCl. In addition, probe Gal-NPA could completely react to HOCl within 3 s meanwhile accompanied by tremendous fluorescence enhancement. The quantitative linear range between fluorescence intensities and the HOCl concentrations was 0 to 1 μM (detection limit = 0.46 nM). More importantly, fluorescence confocal imaging experiments showed that probe Gal-NPA could discriminate hepatoma cells over other cancer cells and simultaneously trace endogenous HOCl levels in living HepG2 cells. And we thus anticipate that probe Gal-NPA has the potential application for revealing the functions of HOCl in hepatoma cells.

The development of probes for selective detection of mercury ions (Hg2+) is an important mission to accomplish because of the toxicity and ubiquity of Hg2+. Herein, we designed and synthesized a novel fluorescent probe O-(N-butyl-1,8-naphthalimide)-4-yl-O-phenyl carbonothioate (CBONT) for selective and sensitive detection of Hg2+ by turn-on fluorescence spectroscopy. Probe CBONT exhibited a fast response for Hg2+ with excellent sensitivity (limit of detection = 1.9 nM, 3σ/slope), and it might be attributed to the adoption of a new recognition receptor of carbonothioate moiety. Additionally, probe CBONT could serve as a “naked-eye” indicator for Hg2+. Finally, probe CBONT could be successfully applied to detect the concentrations of Hg2+ in real water samples. Our proposed recognition receptor would open up new, exciting opportunities for designing highly selective and ultrasensitive fluorescent probes for the determination of Hg2+ in real water samples.

As a typical reactive oxygen species, peroxynitrite (ONOO−) plays vital roles in various biological functions and pharmacological activities. Specific, sensitive and rapid fluorescent probes are helpful tools for monitoring endogenous peroxynitrite. In this work, a highly selective fluorescent probe BTCBE was designed based on benzothiazole-2-acetonitrile and 4-formylphenylboronic acid pinacol cyclic ester. BTCBE showed the merits of rapid response (

Developing a reliable tool for monitoring peroxynitrite (ONOO−) in the complex organisms is critical to uncover its detailed cellular functions in numerous physiological and pathological processes. Thus, a novel ratiometric fluorescent probe was reasonably designed for ONOO−, in which the rhodol-HBT conjugate dye was chosen as a fluorophore, and hydrazine moiety was adopted as recognition receptor of ONOO−. The probe exhibited outstanding sensitivity, specificity, and a fast response towards ONOO−. More importantly, the probe with a large emission shift (Δλem = 127 nm) has been proven to be capable of tracking ONOO− with high resolution in live cells and zebrafish. This work provides a simple and reliable tool for detecting and imaging ONOO− in the living systems, and thus we anticipate that the designed probe could be used as a powerful imaging tool in unraveling biological functions of ONOO−.

The effects of agricultural wastes on degradation of polycyclic aromatic hydrocarbons(PAHs) and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in PAH-polluted soils were determined by liquid chromatography and real-time quantitative PCR. The results showed that addition of agricultural wastes didn't improve the degradation of PAHs, in the contrary, the degradation of PAHs decreased in the soil added with wheat straw. And the degradation rate of PAHs decreased with increased molecular weight of PAHs. Furthermore, the abundance of AOA and AOB was enhanced in PAH-polluted soils after adding agricultural wastes, the content of pyrene and benzo(a)pyrene has significant negative correlation with the abundance of AOA. These results suggested that the degradation of PAHs can not be promoted through applying agricultural wastes into the soils freshly polluted by PAHs. Pyrene and benzo(a)pyrene would reduce the abundance of AOA, while addition of agricultural wastes could improve the ammonia oxidation function in PAH-polluted soils. This study provided some insights for the remediation and risk assessment of PAH-polluted soils.