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In this study, rose bengal‐derived carbon quantum dots (RB‐CQDs) was synthesized by a one‐step solvothermal method using rose bengal and 1,2‐phenylenediamine as precursors in ethanol at 180 °C for 10 h and purified by silica gel chromatography. The as‐synthesized RB‐CQDs disperses well in water with particle sizes ranging from 0.78 to 2.46 nm and exhibits excitation‐independent yellow fluorescent emission (529 nm), high quantum yield (44.3 %) and good biocompatibility. More importantly, the fluorescence of RB‐CQDs can be selectively quenched by Fe3+ ions with good linear correlation and the detection limit is 19.9 nM. The recoveries of this method in actual water samples are 90 % to 110 % with relative standard deviations less than 5 %. [ABSTRACT FROM AUTHOR]

A ratiometric fluorescent zinc probe 1 of carboxamidoquinoline with a carboxylic acid group was designed and synthesised. Probe 1 exhibits high selectivity for sensing Zn2+; about a 13-fold increase in fluorescence emission intensity and an 82 nm red-shift of fluorescence emission are observed upon binding Zn2+ in EtOH/H2O (1 : 1, V/V) solution. The ratiometric fluorescence response is attributed to the 1 : 1 complex formation between probe 1 and Zn2+ which has been utilised as the basis for the selective detection of Zn2+. The analytical performance characteristics of the proposed Zn2+-sensitive probe were investigated. The linear response range covers a concentration range of Zn2+ from 2.0 × 10-6 to 5.0 × 10-5 mol L-1 and the detection limit is 2.7 × 10-7 mol L-1. The determination of Zn2+ in both tap and river water samples shows satisfactory results. [ABSTRACT FROM AUTHOR]

Abstract: A fluorescent probe 1 for Hg2+ based on a rhodamine–coumarin conjugate was designed and synthesized. Probe 1 exhibits high sensitivity and selectivity for sensing Hg2+, and about a 24-fold increase in fluorescence emission intensity is observed upon binding excess Hg2+ in 50% water/ethanol buffered at pH 7.24. The fluorescence response to Hg2+ is attributed to the 1:1 complex formation between probe 1 and Hg2+, which has been utilized as the basis for the selective detection of Hg2+. Besides, probe 1 was also found to show a reversible dual chromo- and fluorogenic response toward Hg2+ likely due to the chelation-induced ring opening of rhodamine spirolactam. The analytical performance characteristics of the proposed Hg2+-sensitive probe were investigated. The linear response range covers a concentration range of Hg2+ from 8.0×10−8 to 1.0×10−5 molL−1 and the detection limit is 4.0×10−8 molL−1. The determination of Hg2+ in both tap and river water samples displays satisfactory results. [Copyright &y& Elsevier]

Abstract: N-Methyl-α,β,γ,δ-tetraphenylporphine (NMTPPH) has been used to detect trace amount of zinc ions in ethanol–water solution by fluorescence spectroscopy. The fluorescent probe undergoes a fluorescent emission intensity enhancement upon binding to zinc ions in EtOH/H2O (1:1, v/v) solution. The fluorescence enhancement of NMTPPH is attributed to the 1:1 complex formation between NMTPPH and Zn(II) which has been utilized as the basis for the selective detection of Zn(II). The linear response range covers a concentration range of Zn(II) from 5.0×10−7 to 1.0×10−5 mol/L and the detection limit is 1.5×10−7 mol/L. The fluorescent probe exhibits high selectivity over other common metal ions except for Cu(II). [Copyright &y& Elsevier]

[Display omitted] • A Golgi-targetable fluorescent probe for hypochlorous acid has been reported. • The probe displays high sensitivity and high selectivity for HOCl. • The probe can be used for detection of HOCl within the Golgi apparatus of living cells. The Golgi apparatus (GA) is a vital organelle in biological systems and excess reactive oxygen species (ROS) is produced during stress in the Golgi apparatus. Hypochlorous acid (HOCl) is a significant reactive oxygen species and has strong oxidative and antibacterial activity, but excessive secretion of hypochlorous acid can affect Golgi structure or function abnormally, it will lead to a series of diseases including Alzheimer's disease, neurodegenerative diseases, autoimmune diseases, and Parkinson's disease. In present work, a novel fluorescent probe for Golgi localization utilizing naphthalimide derivatives was constructed to detect hypochlorous acid. The fluorescent probe used a derivatived 1,8-naphthalimide as the emitting fluorescence group, phenylsulfonamide as the localization group and dimethylthiocarbamate as the sensing unit. When HOCl was absent, the intramolecular charge transfer (ICT) process of the developed probe was hindered and the probe exhibited a weak fluorescence. When HOCl was present, the ICT process occurred and the probe showed strong green fluorescence. When the HOCl concentration was altered from 5.0 × 10−7 to 1.0 × 10−5 mol·L-1, the fluorescence intensity of the probe well linearly correlated with the HOCl concentration. The detection limit of 5.7 × 10−8 mol·L-1 was obtained for HOCl. The HOCl fluorescent probe possessed a rapid reaction time, a high selectivity and a broad working pH scope. In addition, the probe possessed good biocompatibility and had been magnificently employed to image Golgi HOCl in Hela cells. These characteristics of the probe demonstrated its ability to be used for sensing endogenous and exogenous hypochlorous acids within the Golgi apparatus of living cells. [ABSTRACT FROM AUTHOR]

Heat stroke is a symptom of hyperthermia with a temperature of more than 40 °C, which usually leads to all kinds of physical discomfort and even death. It is necessary to study the mechanism of action of heat stroke on cells or organelles (such as cytotoxicity of heat) and the processes of cells or organelles during heat stroke. Recent studies have shown that there is a certain correlation between heat stroke and lysosome acidity. In order to clarify their relationship, Lyso-NIR-pH, a photostable Si-rhodamine-based near-infrared fluorescent probe, was developed for sensing pH changes in lysosomes during heat stroke in this paper. For Lyso-NIR-pH, a morpholine group is employed as the lysosome-targeting unit and a H+-triggered openable deoxylactam is employed as the response unit to pH. Lyso-NIR-pH can detect pH with a high selectivity and a sensitivity, and its pK a is 4.63. Lyso-NIR-pH also has outstanding imaging performances, such as excellent lysosome-targeting ability, low autofluorescence and photostable fluorescence signal, which are in favor of long-term imaging of pH with accurate fluorescence signals. Moreover, we successfully applied Lyso-NIR-pH to monitor lysosomal pH increases induced by chloroquine and apoptosis in live cells. Finally, we successfully applied Lyso-NIR-pH for monitoring changes of lysosomal pH during heat stroke. These results confirmed that Lyso-NIR-pH is a powerful tool to monitor pH change in lysosomes and study its possible effects. Image 1 • A photostable Si-rhodamine-based near-infrared fluorescent probe, Lyso-NIR-pH , was developed for pH in lysosomes. • Lyso-NIR-pH was successfully applied to monitor lysosomal pH increases induced by chloroquine and apoptosis. • Lyso-NIR-pH was successfully applied to monitor lysosomal pH increases during heat stroke. [ABSTRACT FROM AUTHOR]

Hypochlorite (ClO−), one of reactive oxygen species (ROS), is closely related with many physiological and pathological processes. Especially as one of cellular reactive oxygen species in mitochondria, ClO− can induce mitochondrial permeability, which leads to apoptosis. Thus, developing an effective method which is able to sense ClO− in mitochondria is important. Although fluorescent probe has become a powerful tool for imaging ClO− in mitochondria, most of them suffered from phototoxicity to biosamples, autofluorescence, and photobleaching phenomenon due to their short-wavelength excitations and emissions. Based on advantages of two-photon fluorescent probe and far-red to NIR fluorescent probe, a mitochondria-targetable two-photon fluorescent probe with a turn-on signal in far-red to NIR region, Mito-TP-ClO , was developed for ClO− in this paper. Mito-TP-ClO is consisted of a triphenylphosphonium cations as a mitochondria-targetable unit and a structure of dibenzoylhydrazine as a response unit to ClO−. Mito-TP-ClO exhibited a high sensitivity and a high selectivity to ClO−, with a linear range from 6.0 × 10−8 to 1.0 × 10−5 M and a detection limit of 2.5 × 10−8 M. Due to its large two-photon cross section (267 GM) and far-red to NIR emission, Mito-TP-ClO exhibits excellent performances including low autofluorescence, photostable fluorescence signal, and deep tissue penetration (230 μM). Moreover, Mito-TP-ClO was successfully used to detect endogenous ClO− in bacteria-infected cells and inflammatory mouse model, which confirmed that Mito-TP-ClO is a powerful tool to monitor ClO− in mitochondria and study on effects of hypochlorite on mitochondria. Image 1 • A mitochondria-targetable two photon fluorescent probe Mito-TP-ClO with a far-red to NIR emission was developed for ClO−. • Mito-TP-ClO exhibited a deep tissue penetration of 230 μM for imaging ClO−. • Mito-TP-ClO was successfully applied to visualize endogenous ClO− in bacteria-infected cells and inflammatory mouse model. [ABSTRACT FROM AUTHOR]