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https://www.readbyqxmd.com/read/29792690/a-general-method-to-increase-stokes-shift-by-introducing-alternating-vibronic-structures
#1
Tian-Bing Ren, Wang Xu, Wei Zhang, Xing-Xing Zhang, Zhi-Yao Wang, Zhen Xiang, Lin Yuan, Xiaobing Zhang
Fluorescent dyes have enabled the progress of the broad biomedical fields. However, many commercially available dyes suffer from small Stokes shifts, resulting in poor signal-to-noise ratio and self-quenching on current microscope configuration. In this work, we have developed a general method to significantly increase the Stokes shifts of common fluorophores. By simply appending a 1,4-diethyl-decahydro-quinoxaline (DQ) moiety onto the conjugated structure, we introduced a vibronic backbone that could facilely expand the Stokes shifts, emission wavelength and photo-stability of eleven different fluorophores by more than 3-fold...
May 24, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29792319/a-metal-polydopamine-framework-mpda-as-an-effective-fluorescent-quencher-for-highly-sensitive-detection-of-hg-ii-and-ag-i-ions-through-exonuclease-iii-activity
#2
Ayyanu Ravikumar, Perumal Panneerselvam, Norhashimah Morad
In this paper, we propose a metal-polydopamine framework (MPDA) with specific molecular probe which appears to be the most promising approach to a strong fluorescence quencher. The MPDA framework quenching ability towards various organic fluorophore such as aminoethylcomarin acetate (AMCA), 6-carboxyfluorescein (FAM), carboxyteramethylrhodamine (TAMRA) and Cy5 are used to establish a fluorescent biosensor that can selectively recognize Hg2+ and Ag+ ion. The fluorescent quenching efficiency was sufficient to achieve more than 96%...
May 24, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29787269/highly-emissive-self-assembled-bodipy-platinum-supramolecular-triangles
#3
Jiong Zhou, Yuzhen Zhang, Guocan Yu, Matthew R Crawley, Cressa Ria Palencia Fulong, Alan Eric Friedman, Sanghamitra Sengupta, Jifu Sun, Qing Li, Feihe Huang, Timothy R Cook
Light-emitting supramolecular coordination complexes (SCCs) have been widely studied for applications in the chemical and biological sciences. Herein, we report the coordination-driven self-assembly of two highly emissive platinum(II) supramolecular triangles (1 and 2) containing BODIPY-based bridging ligands. The metallacycles exhibit favorable anticancer activities against HeLa cells (IC50 of 6.41 μM and 2.11 μM). The characteristic ~570 nm fluorescence of the BODIPY moieties in the metallacycles permits their intracellular visualization using confocal microscopy...
May 22, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29786089/spectral-analysis-of-fundus-autofluorescence-pattern-as-a-tool-to-detect-early-stages-of-degeneration-in-the-retina-and-retinal-pigment-epithelium
#4
Tatiana B Feldman, Marina A Yakovleva, Andrey V Larichev, Patimat M Arbukhanova, Alexandra Sh Radchenko, Sergey A Borzenok, Vladimir A Kuzmin, Mikhail A Ostrovsky
PURPOSE: The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). METHODS: RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method...
May 22, 2018: Eye
https://www.readbyqxmd.com/read/29785742/synthesis-and-characterization-of-a-new-bifunctionalized-fluorescent-and-amphiphilic-molecule-to-recruit-sh-containing-molecules-to-membranes
#5
Monique Mertens, Malte Hilsch, Ivan Haralampiev, Rudolf Volkmer, Pablo Wessig, Peter Mueller
The present study describes the synthesis and characterization of an amphiphilic construct which is aimed to recruit SH-containing molecules to membranes. The construct consists of (i) an aliphatic chain to enable the anchoring within membranes, (ii) a maleimide moiety to react with the sulfhydryl group of a soluble (bio)molecule, and (iii) a fluorescence moiety to follow the construct by fluorescence spectroscopy and microscopy. It is shown, that the construct can be incorporated into preformed membranes allowing the application of the approach with biological membranes...
May 22, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29785623/synthesis-spectroscopic-characterization-and-polymerization-abilities-of-blue-and-green-light-emitting-oxazol-5-one-fluorophores
#6
Gulsiye Ozturk Urut, Seher Aydin, Derya Topkaya, Elif Sahin, Serap Alp
New fluorescent thiophenyl group containing oxazol-5-one fluorophores of 3a (4-(3-thiophenylmethylene)-2-phenyloxazol-5-one), 3b (4-(3-thiophenylmethylene)-2-(4-tolyl)oxazol-5-one) and 3c (4-(3-thiophenylmethylene)-2-(4-nitrophenyl)oxazol-5-one) were synthesized and characterized. The newly synthesized oxazol-5-ones absorption and fluorescence characteristics were studied in some solvents of varying polarities. The heterocyclic chromophores were fluorescent, with two of them, 3a and 3b, emitting blue light, whilst the other one, 3c, emitting green light...
May 21, 2018: Journal of Fluorescence
https://www.readbyqxmd.com/read/29785442/photoinduced-intramolecular-charge-transfer-in-a-cross-conjugated-push-pull-enediyne-implications-toward-photoreaction
#7
Anuja Singh, Avik Kumar Pati, Ashok Kumar Mishra
Push-pull organic fluorophores are important owing to their interesting optoelectronical properties. Here we report the photophysics of a new cross-conjugated push-pull enediynyl dye which belongs to an unexplored class of π-conjugated donor-acceptor systems. Two N,N-dimethylaniline moieties serve as donors and one pyrene ring functions as an acceptor via a common Y-shaped 'enediyne' bridge which facilitates the cross-electronic communication. The dye exhibits dual emission from locally excited (LE) and intramolecular charge transfer (ICT) states...
May 22, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29784416/two-ratiometric-fluorescent-probes-for-hypochlorous-acid-detection-and-imaging-in-living-cells
#8
Xiang Han, Chang Tian, Jingjing Jiang, Mao-Sen Yuan, Shu-Wei Chen, Juan Xu, Tianbao Li, Jinyi Wang
Hypochlorous acid plays a very important role in living cells, because it can resist microorganism attack and has a lethal effect on pathogens. The unnormal generation of ClO- can cause tissue damage and corresponding diseases. Detection of ClO- is very necessary in biological systems. In this article, we respectively hybridized the two different water-soluble coumarin (7-hydroxycoumarin and 7-diethylaminocoumarin) fluorophores with a longer-wavelength emissive rhodamine fluorophore to construct an intergrant, and then isothiocyanate was modified with the intergrant to recognized ClO- ...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29784381/synthesis-of-a-selective-ratiometric-fluorescent-probe-based-on-naphthalimide-and-its-application-in-human-cytochrome-p450-1a
#9
Xiuxuan Zhang, Yan Zhou, Xiaofei Gu, Yu Cheng, Manxin Hong, Liqiang Yan, Fulong Ma, Zhengjian Qi
Cytochrome P450s have brought considerable attention to researchers for their significant correlations with metabolic behaviors of procarcinogenic chemicals. To better understand the roles of CYP1A in biological and physiological systems, we developed a novel ratiometric fluorescence probe N-((2-hydroxyl ethoxy) ethyl)- 4-methoxy-1, 8-naphthalimide (NEMN) allowing for selectively and sensitively monitoring the target enzymes under physiological conditions and living cells. The probe was designed based on substrate predilection of CYP1A and its outstanding O-dealkylation capacity, and 1, 8-naphthalimide was chosen as fluorophore on account of its desirable photophysical properties...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29784337/quinoline-derived-fluorescent-probes-for-the-discrimination-of-cys-from-hcys-gsh-and-bioimaging-in-living-cells
#10
Qingqing Wu, Mao Mao, Wenlang Liang, Florian J Stadler
Development of thiol-specific fluorescent probes with selectivity in different thiol compounds is more practical and significant than those without that capacity. In this work, a new quinoline-derived fluorophore, hydroxyl-substituted quinoline-benzo[d]oxazole 6 with high fluorescence quantum yield is synthesized and esterified with acrylic acid to afford two fluorescent probes, BQA-1 and BQA-2 for selectively discriminating Cys from Hcys/GSH based on conjugate addition-cyclization mechanism. BQA-1 exhibits a large ratiometric fluorescence response toward Cys in aqueous pH 7...
August 15, 2018: Talanta
https://www.readbyqxmd.com/read/29781099/flow-cytometric-analysis-of-extracellular-vesicle-subsets-in-plasma-impact-of-swarm-by-particles-of-non-interest
#11
S F W M Libregts, G J A Arkesteijn, A Németh, E N M Nolte-'t Hoen, M H M Wauben
BACKGROUND: Extracellular vesicles (EVs) in plasma are increasingly recognized as potential biomarkers. EV analysis for diagnostic purposes should be robust and should allow analysis of EV subsets in a wide range of abundance and in a large number of patient samples. Flow cytometry offers possibilities to meet these criteria as it allows multi-parameter analysis of individual EVs. However, analysis of plasma EVs is challenging due to their size and heterogeneity and the presence of other submicron-sized particles in plasma that could interfere in EV-analysis...
May 20, 2018: Journal of Thrombosis and Haemostasis: JTH
https://www.readbyqxmd.com/read/29780506/highly-luminescent-biocompatible-ytterbium-iii-complexes-as-near-infrared-fluorophores-for-living-cell-imaging
#12
Yingying Ning, Juan Tang, Yi-Wei Liu, Jing Jing, Yuansheng Sun, Jun-Long Zhang
Herein, we report the design and synthesis of biocompatible Yb3+ complexes for near-infrared (NIR) living cell imaging. Upon excitation at either the visible (Soret band) or red region (Q band), these β-fluorinated Yb3+ complexes display high NIR luminescence (quantum yields up to 23% and 13% in dimethyl sulfoxide and water, respectively) and have higher stabilities and prolonged decay lifetimes (up to 249 μs) compared to the β-non-fluorinated counterparts. This renders the β-fluorinated Yb3+ complexes as a new class of biological optical probes in both steady-state imaging and time-resolved fluorescence lifetime imaging (FLIM)...
April 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780500/disentanglement-of-excited-state-dynamics-with-implications-for-fret-measurements-two-dimensional-electronic-spectroscopy-of-a-bodipy-functionalized-cavitand
#13
John P Otto, Lili Wang, Igor Pochorovski, Samuel M Blau, Alán Aspuru-Guzik, Zhenan Bao, Gregory S Engel, Melanie Chiu
Förster Resonance Energy Transfer (FRET) is the incoherent transfer of an electronic excitation from a donor fluorophore to a nearby acceptor. FRET has been applied as a probe of local chromophore environments and distances on the nanoscale by extrapolating transfer efficiencies from standard experimental parameters, such as fluorescence intensities or lifetimes. Competition from nonradiative relaxation processes is often assumed to be constant in these extrapolations, but in actuality, this competition depends on the donor and acceptor environments and can, therefore, be affected by conformational changes...
April 21, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780462/fluorescent-dyes-and-probes-for-super-resolution-microscopy-of-microtubules-and-tracheoles-in-living-cells-and-tissues
#14
Gražvydas Lukinavičius, Gyuzel Y Mitronova, Sebastian Schnorrenberg, Alexey N Butkevich, Hannah Barthel, Vladimir N Belov, Stefan W Hell
We introduce fluorogenic tubulin probes based on the recently reported fluorescent dyes (510R, 580CP, GeR and SiR) and chemotherapy agents - taxanes (docetaxel, cabazitaxel and larotaxel). The cytotoxicity of the final probe, its staining performance and specificity strongly depend on both components. We found correlation between the aggregation efficiency (related to the spirolactonization of fluorophore) and cytotoxicity. Probe optimization allowed us to reach 29 ± 11 nm resolution in stimulated emission depletion (STED) microscopy images of the microtubule network in living human fibroblasts...
April 7, 2018: Chemical Science
https://www.readbyqxmd.com/read/29780456/design-synthesis-and-time-gated-cell-imaging-of-carbon-bridged-triangulenium-dyes-with-long-fluorescence-lifetime-and-red-emission
#15
M Rosenberg, K R Rostgaard, Z Liao, A Ø Madsen, K L Martinez, T Vosch, B W Laursen
Time-resolved fluorescence offers many advantages over normal steady-state detection and becomes increasingly important in bioimaging. However, only very few fluorophores with emission in the visible range and fluorescence lifetimes above 5 ns are available. In this work, we prepare a series of new aza/oxa-triangulenium dyes where one of the usual oxa or aza bridges is replaced by an isopropyl bridge. This leads to a significant redshift of fluorescence with only moderate reductions of quantum yields and a unique long fluorescence lifetime...
March 28, 2018: Chemical Science
https://www.readbyqxmd.com/read/29777313/gold-nanocluster-based-ratiometric-fluorescent-probes-for-hydrogen-peroxide-and-enzymatic-sensing-of-uric-acid
#16
Dongqin Yang, Minchuan Luo, Junwei Di, Yifeng Tu, Jilin Yan
A method is described for ratiometric fluorometric assays of H2 O2  by using two probes that have distinct response profiles. Under the catalytic action of ferrous ion, the 615 nm emission of protein-stabilized gold nanoclusters (under 365 nm photoexcitation) is quenched by H2 O2 , while an increased signal is generated with a peak at 450 nm by oxidizing coumarin with the H2 O2 /Fe(II) system to form a blue emitting fluorophore. These decrease/increase responses give a ratiometric signal. The ratio of the fluorescences at the two peaks are linearly related to the concentration of H2 O2 in the range from 0...
May 18, 2018: Mikrochimica Acta
https://www.readbyqxmd.com/read/29775058/multiple-click-selective-trna-synthetases-expand-mammalian-cell-specific-proteomics
#17
Andrew C Yang, Haley du Bois, Niclas Olsson, David Gate, Benoit Lehallier, Daniela Berdnik, Kyle D Brewer, Carolyn R Bertozzi, Joshua E Elias, Tony Wyss-Coray
Bio-orthogonal tools enable cell-type-specific proteomics, a prerequisite to understanding biological processes in multicellular organisms. Here we report two engineered aminoacyl-tRNA synthetases for mammalian bio-orthogonal labeling: a tyrosyl ( ScTyrY34G ) and a phenylalanyl ( MmPheT412G ) tRNA synthetase that incorporate azide-bearing noncanonical amino acids specifically into the nascent proteomes of host cells. Azide-labeled proteins are chemoselectively tagged via azide-alkyne cycloadditions with fluorophores for imaging or affinity resins for mass spectrometric characterization...
May 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29774897/development-of-highly-sensitive-fluorescent-probes-for-the-detection-of-%C3%AE-galactosidase-activity-application-to-the-real-time-monitoring-of-senescence-in-live-cells
#18
Mauro Safir Filho, Pascal Dao, Maéva Gesson, Anthony R Martin, Rachid Benhida
We report the development of four novel fluorescent probes to monitor the activity of the β-galactosidase enzyme (β-gal), in vitro and in living cells. The fluorophores are based on a 6-amino-styryl-benzothiazole push-pull core and display a strong ICT emission. The probes encompass the fluorescent motif that is connected to a β-d-galactopyranoside moiety through a self-immolative benzyl carbamate linker (βGal-1-4). The screening of four different fluorophores enabled us to access new light-up and two-band ratiometric reporters...
May 18, 2018: Analyst
https://www.readbyqxmd.com/read/29774672/glucose-sensitive-silicone-hydrogel-contact-lens-toward-tear-glucose-monitoring
#19
Ramachandram Badugu, Edward Albert Reece, Joseph R Lakowicz
Accurate and reliable monitoring of blood glucose is needed for the treatment of diabetes, which has many challenges, including lack of patient compliance. Measuring tear glucose is an alternative to traditional finger-stick tests used to track blood sugar levels, but glucose sensing using tears has yet to be achieved. We report a methodology for possible tear glucose monitoring using glucose-sensitive silicone hydrogel (SiHG) contact lenses, the primary type of lenses available in today's market. Initially, we assessed the interpenetrating polymer network, with nearly pure silicone and water regions, existing in the SiHGs using a polarity-sensitive probe Prodan...
May 2018: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29772060/nucleocytoplasmic-shuttling-the-ins-and-outs-of-quantitative-imaging
#20
Chris Molenaar, Kate L Weeks
Nucleocytoplasmic protein shuttling is integral to the transmission of signals between the nucleus and the cytoplasm. The nuclear/cytoplasmic distribution of proteins of interest can be determined via fluorescence microscopy, following labelling of the target protein with fluorophore-conjugated antibodies (immunofluorescence) or by tagging the target protein with an autofluorescent protein, such as green fluorescent protein (GFP). The latter enables live cell imaging, a powerful approach that precludes many of the artefacts associated with indirect immunofluorescence in fixed cells...
May 17, 2018: Clinical and Experimental Pharmacology & Physiology
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