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Metal enhanced fluorescence

Xuefeng Wang, Hua Wang, Qin Jiang, Yong-Ill Lee, Shengyu Feng, Hong-Guo Liu
In this study, thiophene was linked to polybenzene to generate novel fluorescent probes, namely 3,4-diphenyl-2,5-di(2-thienyl)phenyl-trimethylsilane (DPTB-TMS) with a -SiMe3 substituent and 3,4-diphenyl-2,5-di(2-thienyl)phenyl (DPTB) without the -SiMe3 substituent, respectively. Both of the two compounds exhibit aggregation-enhanced emission (AEE) properties in tetrahydrofuran/water mixtures due to restricted intramolecular rotation of the peripheral groups, which make the two compounds good candidates for the detection of Fe(3+) ions in aqueous-based solutions...
July 13, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Jian Zhu, Hui Chang, Jian-Jun Li, Xin Li, Jun-Wu Zhao
The effect of silicon-coated gold nanoparticles with different gold core diameter and silica shell thickness on the fluorescence emission of CdTe quantum dots (QDs) was investigated. For gold nanoparticles with a diameter of 15nm, silica coating can only results in fluorescence recover of the bare gold nanoparticle-induced quenching of QDs. However, when the size of gold nanoparticle is increased to 60nm, fluorescence enhancement of the QDs could be obtained by silica coating. Because of the isolation of the silica shell-reduced quenching effect and local electric field effect, the fluorescence of QDs gets intense firstly and then decreases...
June 30, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Eman S Elzanfaly, Rania M Youssif, Nahla N Salama, Ahmed S Fayed, Hassan A M Hendawy, Maissa Y Salem
The formation of metal chelates with various ligands may lead to the production of fluorescent chelates or enhance the fluorescence of the chelating agent. This paper describes two sensitive, selective and computer-solved methods, namely, zero order (SF) and second-derivative synchronous spectrofluorimetry (SDSFS) for nano-quantitation of two carbapenems; meropenem (MP) and ertapenem (EP). The methods are based on the chelation of MP with Tb(3+) and EP with Zr(4+) in buffered organic medium at pH 4.0 to produce fluorescent chelates...
July 12, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Kyung-Jo Kim, Am Jang
The adsorption characteristics of three types of standard natural organic matter (NOM) on iron-aluminum (Fe-Al) binary oxide (FAO) and heated aluminum oxide (HAO) under natural surface water condition were investigated using various adsorption isotherms and kinetic models. FAO was synthesized by Fe oxide and Al oxide, mixed using the sol-gel hydrothermal method, and aluminum sulfate was used to make HAO. The amount of adsorbed NOM was increased to 79.6 mg g(-1) for humic acid (HA), 101.1 mg g(-1) for sodium alginate (SA) in the FAO, but the maximum adsorption capacity of bovine serum albumin (BSA) (461...
July 4, 2017: Chemosphere
Bin Li, Jianfei Tian, Dan Zhang, Fuli Tian
A novel fluorescent sensor bearing a quinoline and an anisidine moiety has been developed for highly selective detection of Fe(3+) , which shows photo-induced electron transfer (PET) behavior induced by Fe(3+) . Binding of Fe(3+) to the sensor induced the electron of C = N group transfer from quinoline to iron, the result exhibits fluorescent enhancement. With the features of easy synthesis, simple structural skeleton and excellent sensing ability, the newly synthesized chemosensor also applied as a highly selective fluorescent probe in complex samples containing various competitive metal ions...
July 7, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Xiaoping Li, Ting Wu, Hongxiang Bao, Xianyu Liu, Changlin Xu, Yanan Zhao, Dongying Liu, Hongtao Yu
Rapid urbanization and industrialization may cause increased exposure levels to potential toxic trace elements (PTEs) and associated health risks for population living in cities. The main objectives of this study are to investigate systematically the occurrence, source, fate, and risk of PTE contamination from industrial influence in Baoji urban soil. Seven PTE levels (Pb, Zn, Cu, Cr, V, Sb, and As) were surveyed in 50 composite samples from Baoji urban soil by wavelength dispersive X-ray fluorescence spectrometry...
July 6, 2017: Environmental Science and Pollution Research International
Yuanyuan Liu, Yuanyuan Li, Qi Feng, Na Li, Kai Li, Hongwei Hou, Bing Zhang
A series of naphthaldehyde-2-pyridinehydrazone derivatives were discovered to display interesting 'turn-on' fluorescence response to Zn(2+) in 99% water/DMSO (v/v) at pH 7.0. Mechanism study indicated that different substituent groups in the naphthaldehyde moiety exhibited significant influence on the detection of Zn(2+) . The electron rich group resulted in longer fluorescence wavelengths but smaller fluorescence enhancement for Zn(2+) . Among these compounds, 1 showed the highest fluorescence enhancement of 19-fold with the lowest detection limit of 0...
July 6, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Dong-Mei Wang, Qi-Qi Gai, Rong-Fu Huang, Xingwang Zheng
Development of ultrasensitive method for Hg(2+) analysis is important for human health protection and environment monitoring. In this work, we present a highly sensitive and selective electrochemiluminescence (ECL) assay in a "turn-on" mode for the detection of Hg(2+) through selective assembly of gold nanoparticles (AuNPs) on the surface of indium tin oxide (ITO) electrode. In the absence of Hg(2+), the nonthiolated ssDNA could protected AuNPs against its assembly on ITO surface, producing rather low ECL emission for Ru(bpy)3(2+)/TPA system...
June 28, 2017: Biosensors & Bioelectronics
Yao Yu, Youshen Wu, Jiajun Liu, Yiming Liu, Daocheng Wu
On the basis of finite-difference time-domain simulations, a novel strategy is developed to prepare highly efficient bis(2-(2'-benzothienyl)pyridinato-N, C(3)')iridium (BTP) and AuNP polyiohexol composite nanoparticles (BAPI NPs) as dual-modal phosphorescence/computed tomography (CT) bioprobes. In these bioprobes, BTP and AuNPs are both encapsulated with polyiohexol NPs. All bioprobe components perform two functions here: AuNPs could be used as both a CT contrast agent and a phosphorescence enhancement reagent of BTP with a metal-enhancement fluorescence effect...
July 13, 2017: Nanoscale
Ren-Wu Huang, Yong-Sheng Wei, Xi-Yan Dong, Xiao-Hui Wu, Chen-Xia Du, Shuang-Quan Zang, Thomas C W Mak
Silver(i) chalcogenide/chalcogenolate clusters are promising photofunctional materials for sensing, optoelectronics and solar energy harvesting applications. However, their instability and poor room-temperature luminescent quantum yields have hampered more extensive study. Here, we graft such clusters to adaptable bridging ligands, enabling their interconnection and the formation of rigid metal-organic frameworks. By controlling the spatial separation and orientation of the clusters, they then exhibit enhanced stability (over one year) and quantum yield (12...
July 2017: Nature Chemistry
Jian-Feng Li, Chao-Yu Li, Ricardo F Aroca
Fluorescence spectroscopy with strong emitters is a remarkable tool with ultra-high sensitivity for detection and imaging down to the single-molecule level. Plasmon-enhanced fluorescence (PEF) not only offers enhanced emissions and decreased lifetimes, but also allows an expansion of the field of fluorescence by incorporating weak quantum emitters, avoiding photobleaching and providing the opportunity of imaging with resolutions significantly better than the diffraction limit. It also opens the window to a new class of photostable probes by combining metal nanostructures and quantum emitters...
June 22, 2017: Chemical Society Reviews
Xiao Lian, Tifang Miao, Xiaoyu Xu, Chi Zhang, Bing Yan
The harm of plastic pollutants for human and environment is being paid more and more attention. Polystyrene (PS) and styrene are toxic compounds used in large quantities in the production of fiberglass reinforced polyesters. In this work, a simple method was designed for independent detecting polystyrene and styrene biomarker (phenylglyoxylic acid, PGA) in serum and urine. We prepared Eu3+ functionalized Sc-based metal-organic frameworks as turn-on fluorescent switch for PGA. The distinct enhanced luminescence is observed from the Eu@MOFs with addition of PGA...
June 10, 2017: Biosensors & Bioelectronics
A C Gonçalves, J Luis Capelo, C Lodeiro, A A Dos Santos
A new selenium containing coumarin (compound 7) was designed and synthesized from the amide linkage between coumarin-519 (6) and 2-(butylselanyl)ethanamine (5). The molecular structure of 7 was accurately characterized, and its photophysical properties in acetonitrile, ethanol and chloroform solutions were studied by absorption, stationary and time-resolved fluorescence spectroscopies. Changes in the solvent polarity affected the Stokes shift, quantum yields and lifetime of the excited states. The spectroscopic behavior of compound 7 was evaluated in the presence of different monovalent, divalent and trivalent metallic cations (Na(+), K(+), Ca(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), Pb(2+), Hg(2+), Hg(+), Ag(+), Al(3+), Fe(3+), Ga(3+) and Cr(3+)) in acetonitrile solution...
July 1, 2017: Photochemical & Photobiological Sciences
Jing Li, Shuhua Han
A novel chemosensor TrisRh based on tris(2-aminoethyl)amine and rhodamine 6G is designed and synthesized as a fluorescence turn-on probe for Co(2+) ions that is paramagnetic with a property of quenching fluorescence. Rhodamine spirolactam forms are nonfluorescent, whereas, ring-opening of corresponding spirocyclic induced by Co(2+) results in strong fluorescence emission. Upon the addition of Co(2+) ions, TrisRh can display significant enhancements in absorbance and fluorescence intensity as well as evident colorific transformation, which can be perceived by the naked eye...
June 7, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Keyur D Bhatt, Hemangini D Shah, Manthan Panchal
A new fluorescence receptor calix[4]pyrrole-N-(quinoline-8-yl) acetamide (CAMQ) containing a pyrrolic ring connected via the meso-position was synthesized, purified and characterized by elemental analysis, NMR and mass spectroscopy. This compound was examined for its fluorescence properties towards different metal ions e.g. Ag(I), Hg(II), Co(II), Ca(II), Ni(II), Zn(II), Cr(II), Ba(II), Fe(II), Cu(II), Pb(II)and Mg(II) ions by spectrophotometry and spectrofluorometry. It was concluded that the compound (CAMQ) possessed significantly enhanced selectivity for Pb(II) and Cu(II) ions in dimethyl sulfoxide (DMSO) even at very low concentrations (1 μM)...
June 7, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Najim Akhtar, Sanjay Kisan Metkar, Agnishwar Girigoswami, Koyeli Girigoswami
Zinc oxide (ZnO) is a semiconductor metal oxide nanoparticle with inherent optical properties. Among the different zinc oxide nanostructures, nanoflowers have greater surface area. Utilizing this property a reagentless biosensor has been developed for the detection of beta amyloids, a hallmark of neurodegenerative diseases like Alzheimer's disease, Creutzfeldt-Jakob Syndrome, insulin dependent type II diabetes etc. The poor fluorescence quantum yield and photobleaching effect of Thioflavin T (ThT) upon binding to the model insulin amyloid beta sheets in solution can be overcome by the present engineered biosensor where ThT acts as a target as well as a reporter to detect amyloids adsorbed on a solid template based on ZnO nanoflower...
September 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Keying Cai, Mulan Zeng, Fenfen Liu, Nan Liu, Zhenzhong Huang, Yonghai Song, Li Wang
An easy and effective strategy for synthesizing a ratiometric fluorescent nanosensor has been demonstrated in this work. Novel fluorescent BSA-AuNPs@Tb-AMP (BSA, bovine serum albumin; AMP, adenosine 5'-monophosphate; AuNPs, Au nanoparticles) metal-organic framework (MOF) nanostructures were synthesized by encapsulating BSA-AuNPs into Tb-AMP MOFs for the detection of 2,6-pyridinedicarboxylic acid (DPA) and Hg(2+) . DPA could strongly co-ordinate with Tb(3+) to replace water molecules from the Tb(3+) center and accordingly enhanced the fluorescence of Tb-AMP MOFs...
June 1, 2017: Luminescence: the Journal of Biological and Chemical Luminescence
Jing-Xing Wu, Bing Yan
A highly fluorescent metal-organic framework (In-MOF, In(OH)bpydc (bpydc=biphenyl-5,5'-dicarboxylate)) imparting additional luminescent Eu(3+) ions has been synthesized for sensing organic molecules and anions, especially chloroform and MnO4(-), both of them have a significant spectral response. This Eu(3+)-incorporated hybrid (In-MOF-Eu) has been fully characterized, which reveals large surface area, great pore size, favorable thermal stability, excellent luminescence as well as good fluorescence stability...
May 19, 2017: Journal of Colloid and Interface Science
Tânia Ribeiro, Carlos Baleizão, José Paulo S Farinha
Metal nanoparticles can either quench or enhance the emission of dyes in their vicinity, but the precise measurement and understanding of this effect is still hindered by experimental artifacts, especially for particles in colloidal dispersion. Here, we introduce a new methodology to correct the inner filter effect of the metal on the dye emission. To test the method, we developed new hybrid nanoparticles with a gold core and a silica shell of precise thickness (tuned from 7 to 13 nm), with a high quantum yield perylenediimide dye on the surface...
May 26, 2017: Scientific Reports
Trisha Das, Ankita Roy, Hiroshi Uyama, Partha Roy, Mahasweta Nandi
Mesoporous silica functionalized with a 2-hydroxy-naphthyl moiety has been synthesized and characterized by standard techniques like powder X-ray diffraction, N2 adsorption/desorption studies, transmission electron microscopy and spectral studies like FT-IR, UV-visible, fluorescence and (13)C and (29)Si solid state NMR. The functionalized silica material showed significant enhancement in its emission intensity in the presence of Al(3+) ions whereas other metal ions could not bring about any increase in its emission intensity...
June 6, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
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