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Metal enhanced fluorescence

Ying-Chen Chiang, Chun-Ta Huang, Wei Hsin Wang, Cheng-Chung Chang
This manuscript describes the preparation of water soluble aggregation-induced emission enhancement (AIEE)-based fluorescent organic nanoparticles (FONs). The fluorescence diversity of the FONs was investigated in the presence of silver nanowires. We observed that the emission of the FONs can be enhanced by mixing with the nanowires, which is believed to originate from resonance between the emission of the FONs and the surface plasmon resonances of the metal surface. That is, the AIEE phenomenon was promoted according to the metal-enhanced fluorescence (MEF) mechanism that can be used to build up a novel double emission enhancement (DEE) platform and to extend the range of AIEE applications...
December 1, 2016: Faraday Discussions
Kun-Peng Wang, Zhi-Hui Jin, Hui-Shi Shang, Cheng-Dong Lv, Qi Zhang, Shaojin Chen, Zhi-Qiang Hu
A coumarin-appended rhodamine derivative was prepared by reacting rhodamine hydrazide and coumarin-3-carboxylic acid, which fluorescence sensing behavior toward Zn(2+) against other metal ions was investigated in CH3CN. Significantly, the rodamine-coumarin derivative exhibited highly selective and sensitive recognition toward Zn(2+) with a limit of detection (LOD) down to 10(-9) M. Upon addition of Zn(2+), remarkable fluorescent intensities enhanced and also clear color changed from colorless to pink. The Job's plot indicated the formation of 1:1 complex between the rhodamine-coumarin derivative and Zn(2+)...
November 29, 2016: Journal of Fluorescence
Xueliang Liu, Paola A Lopez, Tobias W Giessen, Michael Giles, Jeffrey C Way, Pamela A Silver
Genetically encoding the synthesis of functional nanomaterials such as magnetic nanoparticles enables sensitive and non-invasive biological sensing and control. Via directed evolution of the natural iron-sequestering ferritin protein, we discovered key mutations that lead to significantly enhanced cellular magnetism, resulting in increased physical attraction of ferritin-expressing cells to magnets and increased contrast for cellular magnetic resonance imaging (MRI). The magnetic mutants further demonstrate increased iron biomineralization measured by a novel fluorescent genetic sensor for intracellular free iron...
November 29, 2016: Scientific Reports
Lijun Tang, Shuangli Ding, Keli Zhong, Shuhua Hou, Yanjiang Bian, Xiaomei Yan
A new 2-(2'-hydroxyphenyl)quinazolin-4(3H)-one derived acylhydrazone (QP) was designed and synthesized as a fluorescent sensor. In Tris∙HCl buffer (10mM, pH7.4)/ethanol (1/9, v/v) solution, QP exhibits a highly selective fluorescence response to Al(3+) over other metal ions with a significant blue-shifted and enhanced emission at 473nm. QP interacts with Al(3+) reversibly through a 1:2 binding ratio with a detection limit of 4.79×10(-8)M. Potential applicability of QP for Al(3+) detection in tap and lake water samples were also examined by 'proof-of-concept' experiments...
November 20, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Lei Wang, Zhigang Xie
Polymer-modified metal-organic frameworks combine advantages of both soft polymers and crystalline metal-organic frameworks (MOFs). It is a big challenge to develop simple method for surface modification of MOFs. In this work, a MOFs@microporous organic polymers (MOPs) hybrids nanoparticle (UNP) has been synthesized by epitaxial growth of luminescent BODIPYs-imine MOPs on the surface of UiO-MOFs seeds, which exhibits low cytotoxicity, smaller size distribution, well-retained pore integrity and available functional sites...
November 22, 2016: Chemistry: a European Journal
Anita Toscani, Khairil A Jantan, Jubeda B Hena, Jonathan A Robson, Emily J Parmenter, Valentina Fiorini, Andrew J P White, Stefano Stagni, James D E T Wilton-Ely
The versatile rhenium complex [ReCl(CO)3(bpyC[triple bond, length as m-dash]CH)] (HC[triple bond, length as m-dash]Cbpy = 5-ethynyl-2,2'-bipyridine) is used to generate a series of bimetallic complexes through the hydrometallation of [MHCl(CO)(BTD)(PPh3)2] (M = Ru, Os; BTD = 2,1,3-benzothiadiazole). The ruthenium complex [Ru{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}Cl(BTD)(CO)(PPh3)2] was characterised structurally. Ligand exchange reactions with bifunctional linkers bearing oxygen and sulfur donors provide access to tetra- and pentametallic complexes such as [{M{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}(CO)(PPh3)2}2(S2CNC4H8NCS2)] and Fe[C5H4CO2M{CH[double bond, length as m-dash]CH-bpyReCl(CO)3}(CO)(PPh3)2]2...
November 22, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Yun-Fei Li, Feng-Xi Dong, Yang Chen, Xu-Lin Zhang, Lei Wang, Yan-Gang Bi, Zhen-Nan Tian, Yue-Feng Liu, Jing Feng, Hong-Bo Sun
The transfer-free fabrication of the high quality graphene on the metallic nanostructures, which is highly desirable for device applications, remains a challenge. Here, we develop the transfer-free method by direct chemical vapor deposition of the graphene layers on copper (Cu) nanoparticles (NPs) to realize the hybrid nanostructures. The graphene as-grown on the Cu NPs permits full electric contact and strong interactions, which results in a strong localization of the field at the graphene/copper interface...
November 22, 2016: Scientific Reports
Shilpa Bothra, Yachana Upadhyay, Rajender Kumar, Suban K Sahoo
Vitamin B6 cofactor pyridoxal 5'-phosphate (PLP) and PLP crowned gold nanoparticles (PLP-AuNPs) was applied for the optical chemosensing of metal ions in aqueous medium. PLP showed a visually detectable colour change from colourless to yellow and 'turn-off' fluorescence in the presence of Fe(3+). The fluorescence intensity of PLP at 433nm was also blue-shifted and enhanced at 395nm upon addition of Al(3+). When the PLP was functionalized over AuNPs surface, the wine red colour of PLP-AuNPs was turned to purplish-blue and the SPR band at ~525nm was red-shifted upon addition of Al(3+), Cd(2+) and Pb(2+) due to the complexation-induced aggregation of nanoparticles...
November 13, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Pradeepkumar Jagadesean, Tyler Whittemore, Toni Beirl, Claudia Turro, Psaras McGrier
The synthesis and photophysical properties of three tris(salicylideneaniline) (TSA) compounds containing 1,3,5-triarylbenzene, -tristyrylbenzene and -triarylethynylbenzene core units are reported. The TSA compounds undergo efficient excited state intramolecular proton transfer (ESIPT) in solution and in solid state due to the preformed C=N---H-O hydrogen bonded motifs of the structures. Steady state fluorescence emission spectra of the TSA molecules revealed dual bands in only DMSO, and large Stokes shifts in other polar aprotic and protic solvents...
November 17, 2016: Chemistry: a European Journal
Huixin Zhang, Luping Zhao, Dongxue Sun, Zhiyue Cai, Jie Zhang, Xu Han, Xiaohui Guo, Manli Cui, Duanduan Xie
Carboxymethyl-quaternary ammonium oligochitosan (CM-QAOC) exhibited high inhibition to scaling and microbial formation and also remarkable fluorescence. In this paper its fluorescent properties and application as a fluorescent tracing chemical for industrial water treatment were studied in detail. The fluorescence intensities of CM-QAOC were in good linear agreement with its content in the concentration range of 5 to 500 mg/L and in the range of pH 7 to 9, which shows CM-QAOC can trace itself directly. The results showed the fluorescence would not be influenced by common phosphorus-containing organic and inorganic water treatment chemicals and N-dodecyl-N,N-dimethyl-benzenemethanaminium chloride...
November 2016: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Qitian Lin, Jessica J Gruskos, Daniela Buccella
Fluorescent sensors with low-energy excitation are in great demand for the study of cellular Mg(2+) by fluorescence miscroscopy, but to date they remain scarce. Addressing this gap, we report herein a new set of molecular fluorescent sensors for the detection of Mg(2+) based on an o-aminophenol-N,N,O-triacetic acid (APTRA) metal-recognition moiety combined with two different BODIPY fluorophores. The new sensors, MagB1 and MagB2, display absorption and emission maxima in the visible range and respond to Mg(2+) in aqueous buffer with large fluorescence enhancements...
November 18, 2016: Organic & Biomolecular Chemistry
Chengyun Zhang, Qingyan Han, Caixia Li, Mingdi Zhang, Longxiang Yan, Hairong Zheng
A single silica-shell isolated Au-Ag alloy nanoparticle is used for investigating a metal-enhanced fluorescence effect. Well-dispersed alloy nanoparticles are prepared by the facile chemical method, and the property of local surface plasmon resonance is controlled by adjusting the metal component of the alloy and shell thickness. The distance dependence of fluorescence enhancement for a single Au-Ag alloy nanoparticle is studied systematically with different silica shell thickness ranging from 2 to 35 nm. The isolation shell not only adjusts the distance between metal surface and fluorophore emitters but also improves the chemical stability of the metal particle...
November 10, 2016: Applied Optics
Zahra Bagheri, Reza Massudi
An analytical quantum model is used to calculate electrical permittivity of a metal nanoparticle located in an adjacent molecule. Different parameters, such as radiative and non-radiative decay rates, quantum yield, electrical field enhancement factor, and fluorescence enhancement are calculated by such a model and they are compared with those obtained by using the classical Drude model. It is observed that using an analytical quantum model presents a higher enhancement factor, up to 30%, as compared to classical model for nanoparticles smaller than 10 nm...
November 16, 2016: Applied Spectroscopy
Yau-Tsz Lai, Ya Yang, Ligang Hu, Tianfan Cheng, Yuen-Yan Chang, Mohamad Koohi-Moghadam, Yuchuan Wang, Jiang Xia, Junwen Wang, Hongyan Li, Hongzhe Sun
Metalloproteins account for nearly one-third of proteins in proteomes. To date, the identification of metalloproteins relies mainly on protein purification and the subsequent characterization of bound metals, which often leads to losses of metal ions bound weakly and transiently. Herein, we developed a strategy to visualize and subsequently identify endogenous metalloproteins and metal-binding proteins in living cells via integration of fluorescence imaging with proteomics. We synthesized a "metal-tunable" fluorescent probe (denoted as M(n+)-TRACER) that rapidly enters cells to target proteins with 4-40 fold fluorescence enhancements...
November 10, 2016: Metallomics: Integrated Biometal Science
Tao Lan, Feng-He Wang, Xing-Jun Xi, Chun-Wen Cheng, Wu Lei, Ming-Zhu Xia, Feng-Yun Wang
A Rhodamine-based dual chemosensor L1 for simultaneously detecting Fe(3+) and Cu(2+) was designed and synthesized. The spectroscopic properties of L1 were analyzed, and its recognition mechanism was speculated. We found that the addition of Fe(3+) induced a great fluorescence enhancement, while Cu(2+) induced a strong UV-Vis absorption enhancement. The results revealed that L1 was highly selective for recognizing Fe(3+) and Cu(2+) in UV-Vis spectroscopy in CH3OH-H2O (1/1, v/v, pH 7.2) with the interference of other metal ions...
2016: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Mengqi Zou, Daxiu Li, Ruo Yuan, Yun Xiang
Based on target-induced immuno-proximity binding and metal ion-dependent DNAzyme recycling signal amplification, we describe the development of a homogeneous and sensitive fluorescent method for the detection of protein cancer biomarkers by using α-fetoprotein (AFP) as the model target. Two DNA strands with short complementary regions are conjugated to the AFP antibodies to prepare the recognition probes. The hybridization of the two DNAs in the absence of the AFP target molecules is inhibited due to the low melting temperature (Tm) of the complementary regions...
October 19, 2016: Biosensors & Bioelectronics
Lishi Jiao, Mingyue Liu, Monalisa Garai, Nengyue Gao, Jing Yang, Qing-Hua Xu, Minghui Hong
The local field enhancement in proximity of metallic nanostructures can strongly modify the excitation and emission behaviors for the nearby fluorophore. In this paper, Maxwell's time-dependent curl equations are solved by the finite-difference time-domain method to investigate the electric field enhancement around an atomic-force microscopy (AFM) tip and a Au nanosphere (NS). To lower the background fluorescence signal, we proposed to induce the fluorescence quenching by placing the emitter at an optimized position that is 2 nm away from the Au NS...
November 1, 2016: Applied Optics
Jin-Biao Liu, Li-Juan Liu, Zhen-Zhen Dong, Guan-Jun Yang, Chung-Hang Leung, Dik-Lung Ma
A long-lived aldol reaction-based iridium(III) chemosensor [Ir(ppy)2(5-CHOphen)]PF6 (1, where ppy = 2-phenylpyridine and 5-CHOphen = 1,10-phenanthroline-5-carbaldehyde) for proline detection has been synthesized. The iridium(III) complex 1, incorporating an aldehyde group in N^N donor ligand, can take part in aldol reaction with acetone mediated by proline. The transformation of the sp(2)-hybridized carbonyl group into a sp(3)-hybridized alcohol group influences the metal-to-ligand charge-transfer (MLCT) state of the iridium(III) complex, resulting in a change in luminescence in response to proline...
November 4, 2016: Scientific Reports
Juan He, Han Yang, Yayun Zhang, Jie Yu, Longfei Miao, Yonghai Song, Li Wang
Herein, a smart porous material, Cu-hemin metal-organic-frameworks (Cu-hemin MOFs), was synthesized via assembling of Cu(2+) with hemin to load glucose oxidase (GOD) for electrochemical glucose biosensing for the first time. The formation of the Cu-hemin MOFs was verified by scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, N2 adsorption/desorption isotherms, UV-vis absorption spectroscopy, fluorescence spectroscopy, thermal analysis and electrochemical techniques...
November 4, 2016: Scientific Reports
Rahul S Kathayat, Lijun Yang, Tosaporn Sattasathuchana, Laura Zoppi, Kim K Baldridge, Anthony Linden, Nathaniel S Finney
We provide herein a mechanistic analysis of aryl sulfoxide excited state processes, inspired by our recent report of aryl sulfoxide-based fluorescent chemosensors. The use of aryl sulfoxides as reporting elements in chemosensor development is a significant deviation from previous approaches, and thus warrants closer examination. We demonstrate that metal ion binding suppresses non-radiative excited state decay by blocking formation of a previously unrecognized charge transfer excited state, leading to fluorescence enhancement...
November 3, 2016: Journal of the American Chemical Society
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