1,721,011 research outputs found
Diselenide-based probe for the selective imaging of hypochlorite in living cancer cells
No full textA non-traditional and robust probe skeleton was derivatized for chemosensing applications to investigate a potential novel mode of hypochlorite detection. The BDPP-DSe probe gave a ∼180-fold turn-on response to hypochlorite. Confocal fluorescence imaging demonstrated detection of hypochlorite in living cells and cell membrane permeability. © The Royal Society of Chemistry 20167
Real nerve agent study assessing pyridyl reactivity: Selective fluorogenic and colorimetric detection of Soman and simulant
No full textHerein, a chemical probe is tested with live agents for the purpose of benchmarking fluorescent pyridyl-containing systems with actual nerve agents and simulants together. The molecule showed selective fluorogenic and colorimetric detection of Soman (GD) and its simulant over other G-series nerve agents and their simulants. H-1 and P-31 NMR spectroscopy and TD-DFT calculations help reveal the origin of the colorimetric and fluorogenic changes in the reacted system. (C) 2016 Elsevier B.V. All rights reserved1661sciescopu
Fluorescent Sensing of a Nerve Agent Simulant with Dual Emission over Wide pH Range in Aqueous Solution
No full textA new 1,8-naphthalimide-based fluorescent probe for the detection of diethyl cyanophosphonate, a very common nerve agent simulant, is designed, synthesized, and characterized fully. The probe shows around 50-fold enhancement of fluorescence intensity over other nerve agent simulants. Importantly, the probe is able to work under aqueous conditions in a wide pH range. Two reactive groups, the oxime and the phenol, allow a dual emission with different kinetic reactions. The reaction of diethyl cyanophosphonate with the oxime group occurs in advance; the resulting time response of the fluorescence enhancement is observed within approximately 30 s. After the oxime reaction, then phenol also undergoes a substitution reaction with diethyl cyanophosphonate, resulting in a blue emission. The real application of this new probe is demonstrated through the use of silica plate assays for the detection of diethyl cyanophosphonate in both gas and liquid phases through dual emission channels. (c) 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim7
Nerve agent simulant diethyl chlorophosphate detection using a cyclization reaction approach with high stokes shift system
No full textA reaction-based fluorescent probe (CoumNMe2) containing a coumarin-4-dimethyaminoaryl scaffold for the detection of nerve agent simulants was developed. The probe showed fluorescence enhancement selectively with diethyl chlorophosphate (DCP) over close competitors diethyl cyanophosphonate (DECP), and diethyl methylphosphonate (DEMP) with very little interference from metal ions. O-P bond formation by reaction of the benzyl alcohol motif on the probe with DCP, favours intramolecular cyclization that leads to the ammonium salt. The cyclization strongly inhibits the photo-induced electron transfer (PET) process, which leads to the enhancement of fluorescence intensity (∼10 fold). Also, DFT/TDDFT calculations were exploited to explain the nature of the fluorescence “turn-on” process. Herein, we report a new fluorescent probe (CoumNMe2) based on the intramolecular cyclization reaction for the detection of nerve agent simulant and has potential for real applications. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique9
Substituent Effects in BODIPY in Live Cell Imaging
No full textSmall-molecule organoselenium-based fluorescent probes possess great capacity in understanding biological processes through the detection of various analytes such as reactive oxygen/nitrogen species (ROS/RNS), biothiols (cysteine, homocysteine and glutathione), lipid droplets, etc. Herein, we present how substituents on the BODIPY system play a significant part in the detection of biologically important analytes for in vitro conditions and live cell imaging studies. The fluorescence of the probe was quenched by 2-chloro and 6-phenyl selenium groups; the probe shows high selectivity with NaOCl among other ROS/RNS, and gives a turn-on response. The maximum fluorescence intensity is attained within ≈1–2 min with a low detection limit (19.6 nm), and shows a ≈110-fold fluorescence enhancement compared to signals generated for other ROS/RNS. Surprisingly, in live cell experiments, the probe specifically located and accumulated in lipid droplets, and showed a fluorescence turn-on response. We believe this turn-on response occurred because of aggregation-induced emission (AIE), which surprisingly occurred only by introducing one lipophilic mesityl group at the meso position of the BODIPY. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei8
Aqueous Red-Emissive Probe for the Selective Fluorescent Detection of Cysteine by Deprotection/Cyclization Cascade Resulting in Large Stokes' Shift
No full textCysteine plays a crucial role in cellular functions and in human pathologies. However, the development of cysteine probes with extremely accurate detection is still a key challenge for the field. Herein, we have fully characterized and developed a novel selective fluorescent probe: red emission, aqueous detection and large Stokes' shift for cysteine (Reals-C). Key in the probe synthesis is a Michael addition onto an acroylate group and subsequent intramolecular cyclization. The probe exhibits analyte detection via an intricate role set up by the leaving groups so to discriminate and form the red-emissive analyte sensing platform (lambda(ex) = 471 nm, lambda(em) = 637 nm) through a chemical cascade pathway. Furthermore, the sensing ability of the probe was demonstrated by both in vitro and in vivo assays. This probe enables for successfully endogenous cysteine sensing in HaCaT human keratinocytes through comparison with a commercial thiol-sensitive probe; Reals-C shows excellent in vivo cysteine detection in a drug-induced animal liver injury model 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Enhanced Doubly Activated Dual Emission Fluorescent Probes for Selective Imaging of Glutathione or Cysteine in Living Systems
No full textThe development of novel fluorescent probes for monitoring the concentration of various biomolecules in living systems has great potential for eventual early diagnosis and disease intervention. Selective detection of competitive species in biological systems is a great challenge for the design and development of fluorescent probes. To improve on the design of fluorescent coumarin-based biothiol sensing technologies, we have developed herein an enhanced dual emission doubly activated system (DACP-1 and the closely related DACP-2) for the selective detection of glutathione (GSH) through the use of one optical channel and the detection of cysteine (Cys) by another channel. A phenylselenium group present at the 4-position completely quenches the fluorescence of the probe via photoinduced electron transfer to give a nonfluorescent species. Probes are selective for glutathione (GSH) in the red region and for cysteine/homocysteine (Cys/Hcy) in the green region. When they were treated with GSH, DACP-1 and DACP-2 showed strong fluorescence enhancement in comparison to that for closely related species such as amino acids, including Cys/Hcy. Fluorescence quantum yields (φF) increased for the red channel (<0.001 to 0.52 (DACP-1) and 0.48 (DACP-2)) and green channel (Cys) (<0.001 to 0.030 (DACP-1) and 0.026 (DACP-2)), respectively. Competing fluorescent enhancements upon addition of closely related species were negligible. Fast responses, improved water solubility, and good cell membrane permeability were all properly established with the use of DACP-1 and DACP-2. Live human lung cancer cells and fibroblasts imaged by confocal microscopy, as well as live mice tumor model imaging, confirmed selective detection. © 2018 American Chemical Societ
Exceptional time response, stability and selectivity in doubly-activated phenyl selenium-based glutathione-selective platform
No full textA phenyl-selenium-substituted coumarin probe was synthesized for the purpose of achieving highly selective and extremely rapid detection of glutathione (GSH) over cysteine (Cys)/homocysteine (Hcy) without background fluorescence. The fluorescence intensity of the probe with GSH shows a ∼100-fold fluorescent enhancement compared with the signal generated for other closely related amino acids, including Cys and Hcy. Importantly, the substitution reaction with the sulfhydryl group of GSH at the 4-position of the probe, which is doubly-activated by two carbonyl groups, occurs extremely fast, showing subsecond maximum fluorescence intensity attainment; equilibrium was reached within 100 ms (UV-vis). The probe selectivity for GSH was confirmed in Hep3B cells by confocal microscopy imaging. © 2015 Royal Society of Chemistry139411sciescopu
Enhanced Fluorescence Turn-on Imaging of Hypochlorous Acid in Living Immune and Cancer Cells
No full textTwo closely related phenyl selenyl based boron-di-pyrromethene (BODIPY) turn-on fluorescent probes for the detection of hypochlorous acid (HOCl) were synthesized for studies in chemical biology; emission intensity is modulated by a photoinduced electron-transfer (PET) process. Probe 2 intrinsically shows a negligible background signal; however, after reaction with HOCl, chemical oxidation of selenium forecloses the PET process, which evokes a significant increase in fluorescence intensity. The fluorescence intensity of probes 1 and 2 with HOCl involves an similar to 18 and similar to 50-fold enhancement compared with the respective responses from other reactive oxygen/nitrogen species (ROS/RNS) and low detection limits (30.9 nM for 1 and 4.5 nM for 2). Both probes show a very fast response with HOCl; emission intensity reached a maximum within 1 s. These probes show high selectivity for HOCl, as confirmed by confocal microscopy imaging when testing with RAW264.7 and MCF-7 cells
(c) 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim121221sciescopu
Thiomaleimide Functionalization for Selective Biological Fluorescence Detection of Peroxynitrite as Tested in HeLa and RAW 264.7 Cells
No full textThe role of fluorescent molecules in diagnosis, treatment as well as in biomedical research has great current medicinal significance and is the focus of concentrated effort across the scientific research spectrum. Related research continues to reveal new practical sensing systems that bear enhanced features for interfacing of substituted molecules with biological systems. As part of an effort to better understand chalcogenide systems, a new dithiomaleimide BODIPY (BDP-NGM) probe has been designed, synthesized and characterized. The fluorescence of BDP-NGM was quenched by the incorporation of [3,4-bis(phenylthio)] on the maleimide-4-phenyl moiety which is, in turn, placed at the meso-position of the BODIPY system. The probe shows a turn-on fluorescence response upon reaction with ONOO-; mass spectral evidence reveals peaks in agreement with products involving oxidation of the sulfur groups to sulfone groups. An about 18.0-fold emission intensity enhancement was found. By comparison, the emission signal from another ROS/RNS, superoxide, gave a modest turn on signal (approximate to 5.0-fold). The reaction is complete within 10 min, judging from the monitoring of the turn-on fluorescence process; the detection limit was found to be 0.4 mu m. BDP-NGM can be used for the detection of ONOO- under both acidic and basic conditions. Live cell imaging showed that the current probe can be used for the selective detection of ONOO- in living systems
(c) 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim11sciescopu
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