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Metal enhanced fluorescence

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https://www.readbyqxmd.com/read/28214744/tuning-of-the-selectivity-of-fluorescent-peptidyl-bioprobe-using-aggregation-induced-emission-for-heavy-metal-ions-by-buffering-agents-in-100-aqueous-solutions
#1
Lok Nath Neupane, Gi Won Hwang, Keun-Hyeung Lee
Smart fluorescent probes of which the detection of specific target molecules can be controlled are attracting remarkable interest. A fluorescent peptidyl bioprobe (1) was rationally synthesized by conjugating tetraphenylethylene, an aggregation-induced emission (AIE) fluorophore with a peptide receptor (AspHis) that acted as hard and intermediate bases. The selective detection of 1 for specific metal ion in 100% aqueous solutions was controlled by the buffering agents with the chelate effect without the change of pH...
February 3, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28208304/boric-acid-functional-lanthanide-metal-organic-frameworks-for-selective-ratiometric-fluorescence-detection-of-fluoride-ions
#2
Zhong-Rui Yang, Man-Man Wang, Xue-Sheng Wang, Xue-Bo Yin
Here, we report that boric acid is used to tune the optical properties of lanthanide metal-organic frameworks (LMOFs) for dual-fluorescence emission and improves the selectivity of LMOFs for the determination of F(-) ions. The LMOFs are prepared with 5-boronoisophthalic acid (5-bop) and Eu(3+) ions as the precursors. Emission mechanism study indicates that 5-bop is excited with UV photons to produce its triplet state, which then excites Eu(3+) ions for their red emission. This is the general story of the antenna effect, but electron-deficient boric acid decreases the energy transfer efficiency from the triplet state of 5-bop to Eu(3+) ions, so dual emission from both 5-bop and Eu(3+) ions is efficiently excited at the single excitation of 275 nm...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28195665/zn2-ion-sensing-by-fluorescent-schiff-base-calix-4-arene-macrocycles
#3
Steve Ullmann, Rene Schnorr, Marcel Handke, Christian Laube, Bernd Abel, Jörg Matysik, Matthias Findeisen, Robert Rüger, Thomas Heine, Berthold Kersting
A new macrocycle H2L comprising fluorescent bis(iminomethyl)phenol and calix[4]arene head units has been synthesized and its coordination chemistry examined. H2L allows the sensitive optical detection of Zn2+ among a series of biologically relevant metal ions by a dual fluorescence enhancement / quenching effect in solution.
February 13, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28194985/nano-endoscopy-with-plasmon-enhanced-fluorescence-for-sensitive-sensing-inside-ultrasmall-volume-samples
#4
Hang Yuan, Jie Liu, Yuexiang Lu, Zhe Wang, Guoyu Wei, Tianhao Wu, Gang Ye, Jing Chen, Sichun Zhang, Xinrong Zhang
Plasmon-enhanced fluorescence (PEF) generally requires the samples settled on a metal substrate and the effective enhancement distance is less than 100 nm, which limit its application in intracellular sensing. Herein, we report a nano endoscopy with PEF effect for sensing analytes inside the extremely small volume samples. The nano endoscopy was fabricated by assembling single nanoporous gold nanowire (PGNW) on the tip of a tungsten needle. It was accurately manipulated to insert into a micro droplet, and an effective sensing was realized at micrometre scale with submicrometer resolution...
January 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192925/two-photon-ratiometric-fluorescence-probe-with-enhanced-absorption-cross-section-for-imaging-and-biosensing-of-zinc-ions-in-hippocampal-tissue-and-zebrafish
#5
Wanying Li, Bingqing Fang, Ming Jin, Yang Tian
Zinc ion (Zn(2+)) not only plays an important function in the structural, catalytic, transcription, and regulatory of proteins, but is also an essential ionic signal to regulate brain neurotransmitters pass process. In this work, we designed and synthesized an intramolecular charge transfer-based ratiometric two-photon fluorescence probe, P-Zn, for imaging and biosensing of Zn(2+) in live cell, hippocampal tissue, and zebrafish. The developed probe demonstrated high two-photon absorption cross section (δ) of 516 ± 77 GM, which increased to 958 ± 144 GM after the probe was coordinated with Zn(2+)...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192912/spectral-interference-elimination-in-soil-analysis-using-laser-induced-breakdown-spectroscopy-assisted-by-laser-induced-fluorescence
#6
Rongxing Yi, Jiaming Li, Xinyan Yang, Ran Zhou, Huiwu Yu, Zhongqi Hao, Lianbo Guo, Xiangyou Li, Xiaoyan Zeng, Yongfeng Lu
The complex and serious spectral interference makes it difficult to detect trace elements in soil using laser-induced breakdown spectroscopy (LIBS). To address it, LIBS-assisted by laser-induced fluorescence (LIBS-LIF) was applied to selectively enhance the spectral intensities of the interfered lines. Utilizing this selective enhancement effect, all the interference lines could be eliminated. As an example, the Pb I 405.78 nm line was enhanced selectively. The results showed that the determination coefficient (R(2)) of calibration curve (Pb concentration range = 14-94 ppm), the relative standard deviation (RSD) of spectral intensities, and the limit of detection (LOD) for Pb element were improved from 0...
February 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28169391/an-anti-fouling-nanoplasmonic-sers-substrate-for-trapping-and-releasing-a-cationic-fluorescent-tag-from-human-blood-solution
#7
Kundan Sivashanmugan, Po-Chun Liu, Kai-Wei Tsai, Ying-Nien Chou, Chen-Hsueh Lin, Yung Chang, Ten-Chin Wen
In bioenvironmental detection, surface-enhanced Raman scattering (SERS) signals are greatly affected by anti-specific biomolecule adsorption, which generates strong background noise, reducing detection sensitivity and selectivity. It is thus necessary to modify the SERS substrate surface to make it anti-fouling to maintain excellent SERS signals. Herein, we propose a zwitterionic copolymer, namely poly(glycidyl methacrylate-co-sulfobetaine methacrylate) (poly(GMA-co-SBMA)), for the surface modification of SERS substrates, which were fabricated and characterized spectroscopically...
February 7, 2017: Nanoscale
https://www.readbyqxmd.com/read/28157895/polarization-dependence-of-plasmon-enhanced-fluorescence-on-au-nanorod-array
#8
Mingdi Zhang, Caixia Li, Chi Wang, Chengyun Zhang, Zhaojin Wang, Qinyan Han, Hairong Zheng
The spatial anisotropy of Au nanorod results in two distinct orientational modes by which the polarization orientation dependence of excitation and emission can be studied. In this work, a periodical distributed metallic nanostructure substrate, which contains an array of Au nanorods, is synthesized, and the polarization dependence of the plasmon enhanced fluorescence effect is investigated experimentally and numerically. It is found that the fluorescence emission enhancement of organic probe fluorophores located at the surface of Au nanorods depends on the polarization angle very sensitively...
January 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28153811/cdte-quantum-dot-based-fluorescent-probes-for-selective-detection-of-hg-ii-the-effect-of-particle-size
#9
Jian Zhu, Zhu-Jun Zhao, Jian-Jun Li, Jun-Wu Zhao
Mercury ions-induced fluorescence quenching properties of CdTe quantum dots (QDs) have been studied using the fluorescence spectroscopic techniques. By using the hydrothermal method, the CdTe QDs with different particles sizes from 1.98 to 3.68nm have been prepared, and the corresponding fluorescence emission wavelength is changed from 518 to 620nm. The fluorescence of QDs is enhanced after linking Bovine serum albumin (BSA) onto the surface of the QDs. Experimental results show that the fluorescence intensity of BSA-coated CdTe QDs could be effectively quenched when Hg(2+) react with BSA-coated CdTe QDs...
January 27, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28150195/multifunctional-liposomes
#10
Bhawani Aryasomayajula, Giuseppina Salzano, Vladimir P Torchilin
Liposomes have come a long way since their conception in the 1960s, when they were envisioned primarily for drug delivery. Besides serving the important function of the delivery of a variety of drugs, liposomes offer a platform for the co-delivery of a range of therapeutic and diagnostic agents with different physicochemical properties. They are also amenable to the addition of various targeting moieties such as proteins, sugars, and antibodies for selective targeting at a desired site, including tumors. Currently, the design of stimuli-sensitive liposomes for drug delivery is a lively area of research...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28143572/poly-lactic-acid-nanoparticles-pla-np-promote-physiological-modifications-in-lung-epithelial-cells-and-are-internalized-by-clathrin-coated-pits-and-lipid-rafts
#11
Camila Macedo da Luz, Matthew Samuel Powys Boyles, Priscila Falagan-Lotsch, Mariana Rodrigues Pereira, Henrique Rudolf Tutumi, Eidy de Oliveira Santos, Nathalia Balthazar Martins, Martin Himly, Aniela Sommer, Ilse Foissner, Albert Duschl, José Mauro Granjeiro, Paulo Emílio Corrêa Leite
BACKGROUND: Poly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce. METHODS: We conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies...
January 31, 2017: Journal of Nanobiotechnology
https://www.readbyqxmd.com/read/28134473/highly-selective-turn-on-fluorescent-chemodosimeter-for-al-iii-detection-via-al-iii-promoted-hydrolysis-of-carbon-nitrogen-double-bond-in-8-hydroxyquinoline-aldehyde-schiff-base
#12
Jinmin Wang, Yuanyuan Li, Kai Li, Xiangru Meng, Hongwei Hou
Fluorescent chemodosimeters based on small organic molecules are widely used in the detection of various analytes. However, chemodosimeters for metal ions detections are still limited in a few transition metals like Hg (II), Cu (II), Fe (III), Au(III), etc. In this work, a fluorescent chemodosimeter of 5-chloro-7-phenyliminomethyl-8-hydroxyquinoline (2) for the detection of Al(III) was reported. Chemodosimeter 2 exhibited a turn-on fluorescence response to Al(III) due to an Al(III)-promoted hydrolysis of carbon-nitrogen double bond reaction...
January 30, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28121418/ruthenium-ii-complex-incorporated-uio-67-metal-organic-framework-nanoparticles-for-enhanced-two-photon-fluorescence-imaging-and-photodynamic-cancer-therapy
#13
Rui Chen, Jinfeng Zhang, Jipsa Chelora, Yuan Xiong, Stephen V Kershaw, King Fai Li, Pik-Kwan Lo, Kok Wai Cheah, Andrey L Rogach, Juan Antonio Zapien, Chun-Sing Lee
Ruthenium(II) tris(bipyridyl) cationic complex (Ru(bpy)3(2+)) incorporated UiO-67 (Universitetet i Oslo) nanoscale metal-organic frameworks (NMOFs) with an average diameter of ∼92 nm were developed as theranostic nanoplatform for in vitro two-photon fluorescence imaging and photodynamic therapy. After incorporation into porous UiO-67 nanoparticles, the quantum yield, luminescence lifetime, and two-photon fluorescence intensity of Ru(bpy)3(2+) guest molecules were much improved owing to the steric confinement effect of MOF pores...
February 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28117978/metallo-toehold-activated-catalytic-hairpin-assembly-formation-of-three-way-dnazyme-junctions-for-amplified-fluorescent-detection-of-hg-2
#14
Xin Li, Jiaqing Xie, Bingying Jiang, Ruo Yuan, Yun Xiang
Because of their irreversible toxicological impacts on the environment and human body, the development of reliable and sensitive Hg(2+) detection methods with high selectivity is of great significance. On the basis of the substantial signal amplification by metallo-toehold-triggered, catalytic hairpin assembly (CHA) formation of three-way DNAzyme junctions, we have constructed a highly selective and sensitive fluorescent sensing system for the determination of Hg(2+) in different environmental water samples...
February 8, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28113076/expression-of-flhma3-a-p1b2-atpase-from-festulolium-loliaceum-correlates-with-response-to-cadmium-stress
#15
Qiang Guo, Lin Meng, Mike W Humphreys, John Scullion, Luis A J Mur
Heavy metal ATPase 3 (HMA3), a P1B2-ATPase, is a key tonoplast transporter involved in mediating the vacuolar sequestration of cadmium (Cd) to detoxify the intake of this element by plants. HMA3 expression in response to Cd stress has not been previously examined in the grass hybrid species Festulolium loliaceum (Huds.) P. Fourn. In this study, FlHMA3 isolated from F. loliaceum was found to comprise 833 amino acid residues with 77% homology to the rice OsHMA3. Transient expression of FlHMA3 fused to enhanced green fluorescent protein in Arabidopsis protoplasts suggested its localization to vacuolar membranes...
January 16, 2017: Plant Physiology and Biochemistry: PPB
https://www.readbyqxmd.com/read/28110683/electronically-tuned-sulfonamide-based-probes-with-ultra-sensitivity-for-ga-3-or-al-3-detection-in-aqueous-solution
#16
Ashwani Kumar, Pil Seok Chae
Three electronically tuned fluorescent probes (1-3) were synthesized by conjugating a fluorescent unit to N,N-bis-(hydroxyethyl)ethylenediamine. Probe 1 bearing an electron-deficient naphthalenedimide unit did not give a fluorescence response to the presence of various metal ions including monovalent metal ions (Na(+), K(+), and Ag(+)), divalent metal ions (Ca(2+), Cd(2+), Co(2+), Ni(2+), Cu(2+), Hg(2+), Pb(2+), and Zn(2+)) and trivalent metal ions (Al(3+), Ga(3+), Fe(3+), and Cr(3+)) in an aqueous solution...
March 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28109965/a-novel-acidic-ph-fluorescent-probe-based-on-a-benzothiazole-derivative
#17
Qiujuan Ma, Xian Li, Suxiang Feng, Beibei Liang, Tiqiang Zhou, Min Xu, Zhuoyi Ma
A novel acidic pH fluorescent probe 1 based on a benzothiazole derivative has been designed, synthesized and developed. The linear response range covers the acidic pH range from 3.44 to 6.46, which is valuable for pH researches in acidic environment. The evaluated pKa value of the probe 1 is 4.23. The fluorescence enhancement of the studied probe 1 with an increase in hydrogen ions concentration is based on the hindering of enhanced photo-induced electron transfer (PET) process. Moreover, the pH sensor possesses a highly selective response to H(+) in the presence of metal ions, anions and other bioactive small molecules which would be interfere with its fluorescent pH response...
January 12, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28107934/tuning-sensitivity-of-a-simple-hydrazone-for-selective-fluorescent-turn-on-chemo-sensing-of-al-3-and-its-application-in-living-cells-imaging
#18
Faiz-Ur Rahman, Amjad Ali, Saira Khan Khalil, Rong Guo, Peng Zhang, Hui Wang, Zhan-Ting Li, Dan-Wei Zhang
Salicylaldehyde based hydrazones 2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (SMPH), 4-methyl-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (MSMPH) and 4-fluoro-2-((2-methyl-2-(pyridin-2-yl)hydrazono)methyl)phenol (FSMPH) were prepared and structurally characterized. These hydrazones exhibited fluorescence "turn on" response toward Al(3+) in dimethyl formamide/water (DMF/H2O) (1: 1) mixture. SMPH showed enhanced emission (70 folds) as compared to MSMPH (46 folds) and FSMPH (28 folds) upon the addition of 3 equivalents of Al(3+)...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28088285/plasmon-enhanced-fluorescence-imaging-with-silicon-based-silver-chips-for-protein-and-nucleic-acid-assay
#19
Bing Yuan, Xiangxu Jiang, Chu Yao, Meimei Bao, Jiaojiao Liu, Yujiang Dou, Yinze Xu, Yao He, Kai Yang, Yuqiang Ma
Metal-enhanced fluorescence shows great potential for improving the sensitivity of fluoroscopy, which has been widely used in protein and nucleic acid detection for biosensor and bioassay applications. In comparison with the traditional glass-supported metal nanoparticles (MNPs), the introduction of a silicon substrate has been shown to provide an increased surface-enhanced Raman scattering (SERS) effect due to the coupling between the MNPs and the semiconducting silicon substrate. In this work, we further study the fluorescence-enhanced effect of the silicon-supported silver-island (Ag@Si) plasmonic chips...
February 22, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28087367/production-of-recombinant-proteins-in-escherichia-coli-tagged-with-the-fusion-protein-cusf3h
#20
Teresa Vargas-Cortez, Jose Ruben Morones-Ramirez, Isaias Balderas-Renteria, Xristo Zarate
Recombinant protein expression in the bacterium Escherichia coli still is the number one choice for large-scale protein production. Nevertheless, many complications can arise using this microorganism, such as low yields, the formation of inclusion bodies, and the requirement for difficult purification steps. Most of these problems can be solved with the use of fusion proteins. Here, the use of the metal-binding protein CusF3H+ is described as a new fusion protein for recombinant protein expression and purification in E...
January 11, 2017: Protein Expression and Purification
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