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Sensitized Fluorescence

Fangyun Xin, Yong Tian, Congcong Gao, Bingpeng Guo, Yulong Wu, Junfang Zhao, Jing Jing, Xiaoling Zhang
The detection of mitochondrial formaldehyde (FA) is of great significance because FA is generated through a one-carbon formaldehyde cycle in mitochondria, and abnormal elevations in FA levels can damage mitochondria by decreasing the mitochondrial membrane potential and inhibiting mitochondrial respiration. Herein, a mitochondria-targetable two-photon probe (Mito-FA-FP) has been well demonstrated. Mito-FA-FP is conjugated with hydrazine as the FA-reactive site and a pyridine derivate as the mitochondria-targetable moiety...
December 12, 2018: Analyst
Juan Ou-Yang, Yongfei Li, Wen-Li Jiang, Shuang-Yan He, Hong-Wen Liu, Chun-Yan Li
The ability to early detect cancer in an accurate and rapid fashion is of critical importance for cancer diagnosis and accurate resection in surgery. γ-Glutamyltranspeptidase (GGT) is overexpressed in several human cancers while keeps low expression in normal microenvironment, and thus recognized as an important cancer biomarker. To date, rational design of a zero cross-talk ratiometric near-infrared (NIR) GGT fluorescent probe for efficiently cancer diagnosis in various biological samples is still a big challenge...
December 12, 2018: Analytical Chemistry
Yingxin Chen, Lin Yang, Yan Huang, Ablikim Obolda, Alim Abdurahman, Zhiyun Lu, Feng Li
In traditional fluorescent organic light-emitting diodes (OLEDs), the upper limit of internal quantum efficiency (IQE) is only 25% because 75 % triplet excitons created on the fluorescent dyes are non-luminous. Here, luminescent radicals are proposed as the sensitizer. Under ideal conditions, electrons and holes firstly recombine on the sensitizer molecule to create doublet excitons, then through energy transfer to generate singlet excitons on the fluorescent dye, finally via radiative decay to emit light. The upper limit of IQE can theoretically reach 100%...
December 12, 2018: Journal of Physical Chemistry Letters
J Vanderlocht, J J B C van Beers, P C Limburg, J Damoiseaux, C Roozendaal
ANCA testing was introduced in many laboratories throughout the world when it was recognized that a significant subset of patients with small vessel vasculopathies presented with such antibodies. Many laboratories developed and introduced in-house testing methods for antigen-specific ANCA detection complementary to indirect immune fluorescence screening. Such in-house tests have proven their merit in diagnosing vasculitis and were important to identify critical steps in the development of antigen-specific assays with high sensitivity and specificity...
2019: Methods in Molecular Biology
M E P Didier, O B Tarun, P Jourdain, P Magistretti, S Roke
Neurons communicate through electrochemical signaling within a complex network. These signals are composed of changes in membrane potentials and are traditionally measured with the aid of (toxic) fluorescent labels or invasive electrical probes. Here, we demonstrate an improvement in label-free second harmonic neuroimaging sensitivity by ~3 orders of magnitude using a wide-field medium repetition rate illumination. We perform a side-by-side patch-clamp and second harmonic imaging comparison to demonstrate the theoretically predicted linear correlation between whole neuron membrane potential changes and the square root of the second harmonic intensity...
December 11, 2018: Nature Communications
Sorour Shojaeian, Abdolamir Allameh, Mahmood Jeddi-Tehrani, Roya Ghods, Jaleh Shojaeian, Akram-Sadat Tabatabaei-Panah, Amir-Hassan Zarnani
In recent years, a lot of attention has been paid to quantum dot (QD) nanoparticles as fluorescent sensors for sensitive and accurate detection of cancer biomarkers. Here, using a homemade specific monoclonal antibody against CA125 and QD525- or FITC-labeled probes, expression of this marker in an ovarian cancer cell line and cancer tissues were traced and optical properties of fluorophores were compared qualitatively and quantitatively. Our results clearly showed that besides lower background and exceptionally higher photobleaching resistance, QD525 exhibited higher fluorescent intensity for both ovarian cancer cell and tissues at different exposure times (p<0...
August 12, 2018: Iranian Journal of Allergy, Asthma, and Immunology
Yaoping Hu, Zhijin Gao, Jie Yang, Hui Chen, Lei Han
The increasing production of waste polyethylene terephthalate (PET) is a growing problem worldwide. Environmentally benign conversion of waste PET to valuable materials remains a substantial challenge. In this paper, we developed a green route to reuse waste PET for low-cost synthesis of fluorescent carbon dots (CDs) via air oxidation followed by hydrothermal treatment in aqueous H2 O2 solution. No expensive, corrosive, or toxic reagents, or severe conditions were required in the synthetic process. The resultant CDs possessed abundant oxygenous groups and unique photoluminescence (PL) properties, which showed a highly selective and sensitive detection of ferric ion (Fe3+ ) through a PL quenching effect (on-off)...
December 4, 2018: Journal of Colloid and Interface Science
Yingping Li, Yong Jia, Qi Zeng, Xiaohui Jiang, Zhengjun Cheng
We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to Förster resonance energy transfer (FRET). Moreover, the rate (KT ) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the KT and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm)...
December 4, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Lyudmila Ignatova, Elena Zhurikova, Boris Ivanov
The carrier of carbonic anhydrase (CA) activity was detected in gel among low molecular mass proteins from pea, spinach and Arabidopsis, after nondenaturing electrophoresis in PAAG of the dodecyl-β-d-maltoside treated PSII membranes (the fragments of thylakoid membrane containing PSII complexes). The elimination of Mn-stabilizing protein PsbO by treatment of PSII membranes with salts, did not lead to a decrease in CA activity observed in the gel although it reduced the amount of this protein down to 25% compared to the original sample...
November 20, 2018: Journal of Plant Physiology
Minghan Cai, Dongdong Zhang, Lian Duan
Recently, organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) materials have aroused huge attention in both academia and industry. Compared with fluorescent and phosphorescent materials, TADF materials can theoretically capture 100 % excitons without incorporating noble metals, making them effective emitters and hosts for OLEDs simultaneously. Here, in this review, our recent works on mechanisms and materials of high performance TADF-sensitized phosphorescent (TSP) OLEDs, TADF-sensitized fluorescent (TSF) OLEDs and TADF-sensitized TADF (TST) OLEDs are summarized...
December 10, 2018: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
Mahmoud A Omar, Dalia M Nagy, Monica E Halim
A novel sensitive and simple spectrofluorimetric method was developed then validated for determination of midodrine in both its authentic pure form and its tablets. This method is based on the reaction between midodrine's aliphatic primary amine moiety with fluorescamine reagent, using borate buffer at pH 7.8 and yielding a highly fluorescent product whose fluorescence intensity was measured at 462 nm after excitation at 388 nm. This method represents the first attempt for determination of midodrine spectrofluorimetrically...
December 10, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
J A Rangel-Méndez, M Graniel-Sabido, J Sanchez-Cruz, R Moo-Puc
To date, several methods for quantification of tamoxifen and its metabolites have been developed, most of which employ liquid chromatography tandem-mass spectrometry (LC-MS/MS). These methods are highly sensitive and reproducible, but are also time-consuming and require expensive equipment; one of its main disadvantages is matrix ionization effects. A more viable option, particularly in developing countries, is high-performance liquid chromatography (HPLC) coupled with UV or fluorescence detection (FLD). We developed and validated a method for simultaneous quantification of tamoxifen, endoxifen, and 4-hydroxytamoxifen based on high performance liquid chromatography with fluorescence detection (HPLC-FLD) in a reverse-phase column...
December 9, 2018: Biomedical Chromatography: BMC
F A Ibrahim, M E Fathy, H M Elmansi
Orciprenaline sulphate (ORP) is a direct-acting sympathomimetic with mainly beta-adrenoceptor stimulant activity. It is used as a bronchodilator in the management of reversible airway obstruction. For the first time, a rapid highly sensitive spectrofluorimetric method is described that is relied on measuring the fluorescence spectra of ORP at acidic pH and without addition of any chemical reagents. The relative fluorescence intensity was measured at 310 nm and after excitation at 224 nm. ORP native fluorescence was calibrated in both water and acetonitrile as diluting solvents...
December 11, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
V Krishnan Ramanujan
Cancer cells are known to display a variety of metabolic reprogramming strategies to fulfill their own growth and proliferative agenda. With the advent of high resolution imaging strategies, metabolomics techniques, and so forth, there is an increasing appreciation of critical role that tumor cell metabolism plays in the overall breast cancer (BC) growth. In this report, we demonstrate a sensitive, flow-cytometry-based assay for rapidly assessing the metabolic phenotypes in isolated suspensions of breast cancer cells...
December 11, 2018: Cytometry. Part A: the Journal of the International Society for Analytical Cytology
Yi-Wei Wang, Qiao Liu, Lixing Wang, Shurong Tang, Huang-Hao Yang, Hongbo Song
A one-step reduction method was used for the preparation of stable graphitic carbon nitride-gold nanoparticles (g-C3 N4 -Au) nanocomposites from ultrathin g-C3 N4 nanosheets and chloroauric acid by using NaBH4 as a reducing agent under ultrasonication. The nanocomposites were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis absorption and fluorescence spectroscopy etc. The results revealed that the gold nanoparticles (AuNPs) are uniformly formed on the g-C3 N4 nanosheets...
December 10, 2018: Mikrochimica Acta
Yanling Hu, Yu He, Yaxue Han, Yili Ge, Gongwu Song, Jiangang Zhou
A rapid method is described for synthesis of copper nanoclusters (CuNCs) by utilizing L-histidine as the stabilizer and ascorbic acid (AA) as the reductant. The CuNCs display blue-green fluorescence with excitation/emission peaks at 390/485 nm. A sensitive fluorometric assay was worked out for determination of alkaline phosphatase (ALP) activity. If the ALP substrate p-nitrophenylphosphate (PNPP) is enzymatically hydrolyzed, it forms p-nitrophenol (PNP) which reduces the fluorescence of CuNCs because its absorption band at 410 nm overlaps the excitation peak of CuNCs at 390 nm...
December 7, 2018: Mikrochimica Acta
Peng Hou, Jing Wang, Shuang Fu, Lei Liu, Song Chen
Based on an excited-state intramolecular proton transfer (ESIPT) fluorophore, a novel fluorescent off-on probe for detection of thiophenols was designed and synthesized. This probe (λex  = 401 nm, λem  = 527 nm) displayed high specificity for sensing thiophenols over other biologically related species. Besides, this probe possessed capabilities of monitoring thiophenols with rapid response rate (3 min), a large Stokes shift (126 nm), and high sensitivity (2.7 nM). The sensing mechanism was considered to be that thiophenols triggered thiolysis of the probe and the ESIPT fluorophore was released, as confirmed by means of HPLC and HRMS...
December 10, 2018: Analytical and Bioanalytical Chemistry
Hongzhi Lu, Chunwei Yu, Shuai Quan, Shoufang Xu
Based on the inner filter effect and charge transfer dual response mechanism, a dual response ratiometric fluorescent probe (D-RFP) with two reversible signal changes for sensing H2O2 and glucose was developed. The D-RFP was proposed by embedding glycine-derived carbon dots (CDs) (λem = 400 nm) into silica nanoparticles and covalently linking CdTe quantum dots (QDs) (λem = 600 nm) onto the surface of silica nanoparticles. When silver nanoparticles (Ag NPs) were mixed with D-RFP, the fluorescence intensity of CDs can be quenched by Ag NPs via the inner filter effect...
December 11, 2018: Analyst
Piaopiao Chen, Shixin Yan, Erica Sawyer, Binwu Ying, Xiawei Wei, Zhengzhi Wu, Jia Geng
Ascorbic acid (AA) and alkaline phosphatase (ALP) serve as an important coenzyme and enzyme in multiple biological metabolism reactions, respectively, and abnormal levels of these substrates have been associated with several diseases. Herein, a new and simple fluorescence strategy has been developed for AA and ALP sensing by exploiting CdTe quantum dots (QDs) as an effective signal indicator. This method is mainly based on the selective fluorescence-quenching reaction between Ag+ and CdTe QDs, as opposed to silver nanoparticles (Ag NPs); Ag+ can be reduced to Ag NPs by AA...
December 10, 2018: Analyst
Estela Climent, Mandy Hecht, Heike Witthuhn, Kornelia Gawlitza, Knut Rurack
The synthesis, characterization, and application of mesoporous materials containing boron-dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of HgII in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye I containing a thia-aza crown ether receptor as the fluorescent probe for the detection of HgII in aqueous environments is encapsulated into mesoporous materials to avoid self-quenching or aggregation in water. Determination of HgII is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt...
December 2018: ChemistryOpen
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