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Herein, we report a novel fluorescent probe based on coumarin to detect cysteine (Cys). The probe can react rapidly and selectively with Cys but not with the other amino acids. When the Cys was added to the solution of the probe, we could observe obvious color change from pale green to bright green. The detection limit of this probe for Cys was found to be 0.06 μM. Additionally, bioimaging of intracellular Cys by this probe was successfully applied in living cells, which indicating that this probe holds great potential for biological applications. [ABSTRACT FROM AUTHOR]

An off-on fluorescent probe (CuCIN), coumarin-naphthol linked by an imine group, for detecting Cu 2+ in DMSO-HEPES buffer (1:99, v/v) solution was successfully developed. Mechanism studies suggested that CuCIN firstly formed a complex with Cu 2+ in a 1:2 metal-to-ligand ratio, and then 60-fold fluorescence enhancement was observed when Cu 2+ promoted the imine hydrolysis to release the fluorescence compound 7-diethylaminocoumarin-3-aldehyde. This probe displayed desired properties such as high selectivity toward other metal ions, low detection limit (12.7 nM) and low cytotoxicity. Bio-imaging study revealed that the new probe CuCIN could be applied for imaging living cells with good cell permeability. We hope to apply this probe in the biomedical research field for the imaging of disease-relevant Cu 2+ . [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel dual-site fluorescent probe (MTRN) for HClO and H 2 S was constructed by combining naphthalimide fluorophore with rhodamine fluorophore. • The detection limits (LOD) for HClO and H 2 S were calculated to be 3.39 nM and 0.13 μM, respectively. • MTRN was successfully exploited for detecting HClO and H 2 S in cell imaging and test strip. HClO and H 2 S commonly coexist in organisms and act synergistically to maintain the redox dynamic balance in vivo; however, it is difficult to trace precisely and simultaneously HClO and H 2 S by single recognition-type fluorescent probes. In this paper, a novel probe (MTRN) was designed for detecting specifically HClO and H 2 S with dual-emission property by using an acrylate and a phenyl isothiocyanate as recognition sites. MTRN possessed outstanding performances including ultrasensitivity (LOD = 3.39 nM), high specificity and short response time (<2 min) for HClO under excitation of 530 nm with the fluorescence's color change from dark to red. Moreover, upon treating with H 2 S, the fluorescence peak centered at 488 nm of MTRN enhanced obviously within 1 min and color changed from colorless to blue, the LOD was found to be 0.13 µM. The possible reaction mechanism for HClO and H 2 S in CH 3 CN/PBS (9/1, v/v) was substantiated via 1H NMR and HRMS. Above all, MTRN was successfully used to detect HClO and H 2 S in HeLa cells and made into test strips to detect HClO and H 2 S. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel benzocoumarin-based fluorescent probe BL for monitoring HOCl was designed and synthesized. • BL exhibits simple synthesis, excellent selectivity, fast response (<60 s), high sensitivity (DL, 5.64 nM). • BL was successfully applied to detect HClO spiked in tap water, 84 disinfectants and lake water, and has achieved satisfying recovery rates. • BL could readily fabricate solid-state visual sensors to be used to convenient detect HClO. • BL was nontoxic andsuccessfully used to monitor the variations of endogenous/exogenous HOCl in live RAW 264.7 macrophages. Hypochlorous acid (HOCl) is widely used in daily production and life. It is also a kind of endogenously produced reactive oxygen species (ROS) in the human immune system, plays a crucial role in many pathophysiological processes. This work designed and synthesized a novel based on benzocoumarin fluorescent probe BL for specific detection HOCl. BL has brilliant selectivity, high sensitivity (5.64 nM), fast response (60 s), moderate water-solubility. The intramolecular charge transfer (ICT) sensing mechanism of BL has been verified by fluorescence, UV, MS, and density functional theory (DFT) calculations. BL can make into a solid-state visual sensor to detect HOCl conveniently. BL was also applied to detect HClO spiked in tap water, 84 disinfectants, lake water, and satisfying recovery rates. Finally, BL was low toxic and used to track the variations of endogenous/exogenous HClO in living cells successfully. Totally, BL provides a powerful and reliable monitoring tool to reveal the biological functions of HOCl and ensure safe use. [ABSTRACT FROM AUTHOR]

Abstract: Acrylic acid 3-acetyl-2-oxo-2 H-chromen-7-yl ester (ACA) was rationally designed and synthesized as a simple and effective fluorescent probe for sensing cysteine with high selectivity and naked-eye detection. The probe can detect cysteine by fluorescence spectrometry with a detection limit of 0.657μM and can be used with calf serum and in live cell imaging. The conjugate addition/cyclization sequence mechanism of the reaction between ACA and cysteine was confirmed by ESI-MS and fluorescence spectra. [Copyright &y& Elsevier]