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Metal enhanced fluorescence

Hai Guo, Cheng-Gang Niu, Xiao-Ju Wen, Lei Zhang, Chao Liang, Xue-Gang Zhang, Dan-Lin Guan, Ning Tang, Guang-Ming Zeng
In this work, the novel ternary AgBr/Ag/PbBiO2Br Z-scheme photocatalysts were synthesized via a CTAB-assisted calcination process. The AgBr/Ag/PbBiO2Br composites were employed for the degradation of rhodamine B (RhB) and antibiotic bisphenol A (BPA) under visible light irradiation. Results showed that the obtained AgBr/Ag-3/PbBiO2Br displayed optimal photocatalytic performance, which could remove almost all RhB within 25 min and effectively decompose 82.3% of BPA in 120 min. Three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs) were utilized for the purposes of fully grasping the behaviors of RhB molecules during the reaction process...
December 5, 2017: Journal of Colloid and Interface Science
Moonseong Park, Charles Soon Hong Hwang, Ki-Hun Jeong
Plasmonic alloy has attracted much interest in tailoring localized surface plasmon resonance (LSPR) for recent biosensing techniques. In particular, paper-based plasmonic substrates allow capillary-driven lateral flow as well as three-dimensional metal nanostructures and therefore they become actively transferred to LSPR-based biosensing such as surface-enhanced Raman spectroscopy (SERS) or metal-enhanced fluorescence (MEF). However, employing plasmonic alloy nanoislands on heat-sensitive substrate is still challenging, which significantly inhibits broad-range tailoring of the plasmon resonance wavelength (PRW) for superior sensitivity...
December 8, 2017: ACS Applied Materials & Interfaces
Yan-Ping Zhao, Jin-Li Cui, Ting-Shan Chan, Jun-Cai Dong, Dong-Liang Chen, Xiang-Dong Li
Chelants are known to enhance metal translocation in plants; however, the underlying mechanisms are still not fully understood. This study aimed to elucidate the distribution and speciation of Cu in ryegrass (Lolium multiflorum) in both absence and presence of the biodegradable chelant [S,S']-ethylenediamine disuccinic acid (EDDS). The results showed that EDDS increased the Cu translocation factor from root to shoot by 6-9 folds under CuEDDS in comparison with free Cu (50-250μM). Synchrotron-based microscopic X-ray fluorescence (μ-XRF) mapping revealed that EDDS alleviated Cu deposition in the root meristem of root apex and the junction of lateral root zone, and facilitated Cu transport to root stele for subsequent translocation upwards...
December 1, 2017: Science of the Total Environment
Ting Ting Zhao, Zhe Wei Peng, Dan Yuan, Shu Jun Zhen, Cheng Zhi Huang, Yuan Fang Li
In this contribution, we demonstrated that Cu-based metal-organic gel (Cu-MOG) was able to serve as a novel amplification platform for fluorescence anisotropy (FA) assay for the first time, which was confirmed by the sensitive detection of a common cancer biomarker, prostate specific antigen (PSA). The dye-labeled probe aptamer (PA) product was adsorbed onto the benzimidazole derivative-containing Cu-MOG via electrostatic incorporation and strong π-π stacking interactions, which significantly increased the FA value due to the enlargement of the molecular volume of the PA/Cu-MOG complex...
October 31, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yanan Pan, Jundong Wang, Xiumei Guo, Xiaoyan Liu, Xiaoliang Tang, Haixia Zhang
In this study, a novel three-dimensional zinc-based metal-organic framework (Zn-MOF), i.e., {Zn2(L)2(DMF)2H2O}n (L = 2,5-bis(phenylamino)-1,4-benzenedicarboxylic acid) was designed and developed under solvothermal condition. As a proof-of-principle, a π-conjugated framework of carboxylate ligand capable of "bottom up" synthesis was integrated with metal ion to construct a novel MOF for sensing applications. As expected, the synthesized Zn-MOF exhibited fluorescence enhancement for cadmium ion (Cd2+) and sensing of nitrobenzene (NB) through fluorescence quenching...
November 11, 2017: Journal of Colloid and Interface Science
Sabrina Simoncelli, Maria Makarova, William Wardley, Dylan M Owen
In the discussion of resolution in optical microscopy, axial precision has often come second to its lateral counterpart. However, biological systems make no special arrangements for our preferred direction of imaging. The ability to measure axial distances, that is, the heights of fluorophores relative to a plane of reference, is thus of paramount importance and has been the subject of several recent advances. A novel method is to modify the fluorescence emission based on the height of the individual fluorophore, such that its z-position is encoded somehow in the detected signal...
November 21, 2017: ACS Nano
Dongdong Wang, Jiajia Zhou, Ruohong Shi, Huihui Wu, Ruhui Chen, Beichen Duan, Guoliang Xia, Pengping Xu, Hui Wang, Shu Zhou, Chengming Wang, Haibao Wang, Zhen Guo, Qianwang Chen
Metal-organic-frameworks (MOFs) possess high porosity, large surface area, and tunable functionality are promising candidates for synchronous diagnosis and therapy in cancer treatment. Although large number of MOFs has been discovered, conventional MOF-based nanoplatforms are mainly limited to the sole MOF source with sole functionality. In this study, surfactant modified Prussian blue (PB) core coated by compact ZIF-8 shell (core-shell dual-MOFs, CSD-MOFs) has been reported through a versatile stepwise approach...
2017: Theranostics
Arnab Mukherjee, Hunter C Davis, Pradeep Ramesh, George J Lu, Mikhail G Shapiro
Magnetic resonance imaging (MRI) is a powerful technique for observing the function of specific cells and molecules inside living organisms. However, compared to optical microscopy, in which fluorescent protein reporters are available to visualize hundreds of cellular functions ranging from gene expression and chemical signaling to biomechanics, to date relatively few such reporters are available for MRI. Efforts to develop MRI-detectable biomolecules have mainly focused on proteins transporting paramagnetic metals for T1 and T2 relaxation enhancement or containing large numbers of exchangeable protons for chemical exchange saturation transfer...
November 2017: Progress in Nuclear Magnetic Resonance Spectroscopy
Sourav Das, Pooja Ghosh, Sudipta Koley, Atanu Singha Roy
The interactions of naringenin (NG) and naringin (NR) with Hen Egg White Lysozyme (HEWL) in aqueous medium have been investigated using UV-vis spectroscopy, steady-state fluorescence, circular dichroism (CD), Fourier Transform infrared spectroscopy (FT-IR) and molecular docking analyses. Both NG and NR can quench the intrinsic fluorescence of HEWL via static quenching mechanism. At 300K, the value of binding constant (Kb) of HEWL-NG complex (5.596±0.063×10(4)M(-1)) was found to be greater than that of HEWL-NR complex (3...
November 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Sarah Elisabeth Ochmann, Carolin Vietz, Kateryna Trofymchuk, Guillermo P Acuna, Birka Lalkens, Philip Tinnefeld
Due to the limited signal-to-background ratio, molecular diagnostics requires molecular amplification of the target molecules or molecular signal amplification after target recognition. For direct molecular detection, we demonstrate a purely physical fluorescence enhancement process which can elevate the fluorescence signal of single fluorescent dyes by several orders of magnitude. To this end, DNA origami-based optical antennas with a height of around 125 nm are used, which utilize metallic nanoparticles to create a hotspot where fluorescence signals are enhanced by plasmonic effects...
November 16, 2017: Analytical Chemistry
Yi Liu, Dong Yao, Hao Zhang
Because of the specific properties including HOMO-LUMO electronic transition, size-dependent fluorescent emission, and intense light absorption, metal nanoclusters (NCs) have been considered to be one of the most competitive color conversion materials in light-emitting diodes (LEDs). However, the monotonous emission color and the low emission stability and intensity of individual metal NCs strongly limit their universal application. Inspired by the concept of "aggregation-induced emission" (AIE), the utilization of highly ordered metal NC assemblies opens a door to resolve these problems...
November 16, 2017: ACS Applied Materials & Interfaces
Gurpreet Singh, Renzhe Bi, U S Dinish, Malini Olivo
A theoretical design and analysis of a tapered-coupler structure on a silicon nitride integrated-photonic platform for coupling optical energy from a dielectric waveguide to a plasmonic tip is presented. The proposed design can be considered as a hybrid photonic-plasmonic structure that generally supports hybrid symmetric and asymmetric modes. Along the taper, one of the hybrid modes approaches the cut-off, while the other approaches the short-range surface plasmon mode that generates localized fields. Potential use of the proposed novel tapered-coupler plasmonic structure for highly sensitive biosensing applications using surface enhanced Raman scattering (SERS) and metal enhanced fluorescence (MEF) techniques is discussed...
November 14, 2017: Scientific Reports
Chanida Boonmee, Vinich Promarak, Thawatchai Tuntulani, Wittaya Ngeontae
A new type of copper nanoclusters was synthesized by a one-pot reaction using cysteamine as a capping agent and reducing agent (Cys-CuNCs). The synthesized CuNCs exhibited a spherical shape and a monodisperse and strong fluorescent emission characteristic peak at 430nm when exciting at 330nm. The Cys-CuNCs were demonstrated as a fluorescent chemodosimeter for the selective detection of Al(3+). In the presence of Al(3+), the fluorescent emission of the Cys-CuNCs was considerably enhanced, while other studied metal ions did not show this phenomenon...
February 1, 2018: Talanta
Dan Li, Zhenhua Chen, Xifan Mei
Noble metal nanoclusters have attracted great attentions in the area of fluorescence related applications due to their special properties such as low toxicity, excellent photostability and bio-compatibility. However, they still describe disadvantages for low quantum yield compared to quantum dots and organic dyes though the brightness of the fluorescence play an important role for the efficiency of the applications. Attentions have been attracted for exploring strategies to enhance the fluorescence based on the optical fundamentals through various protocols...
November 7, 2017: Advances in Colloid and Interface Science
Rostislav Bukasov, Olena Filchakova, Kristina Gudun, Mohamed Bouhrara
Strong surface (metal) enhanced fluorescence (SEF or MEF) is observed from clusters and single E coli bacteria cells labeled with Carbon nanodots (CDs), which were synthesized from date pits. The enhancement factor (EF) for SEF of the cell clusters were close to 50 for both 533 and 633 nm laser excitation wavelength. Those EFs are ratios of emission peak areas from CD labeled cell clusters on gold film to the peak areas of the same batch cell clusters on glass substrate. SEF with 633 nm excitation performed better than SEF with 532 nm excitation, achieving higher fluorescence intensity and much higher contrast...
November 10, 2017: Journal of Fluorescence
Ajcharapan Tantipanjaporn, Samran Prabpai, Kanoknetr Suksen, Palangpon Kongsaeree
A rhodamine-thiourea conjugate RTP with an o-phenylenediamine linker was developed as a fluorogenic chemodosimeter for Hg(2+) detection. In the presence of Hg(2+), a colorless solution of RTP turned pink with a maximum absorption band at 555nm and with a 62-fold fluorescence enhancement at 578nm (Φ=0.34). RTP is highly selective to Hg(2+) among other metal ions with a detection limit of 1.6nM (0.3ppb). A similar rhodamine analog with a flexible ethylenediamine spacer was less selective and less sensitive than RTP...
October 25, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Hyun Chul Park, Isnaeni, Suhyun Gong, Yong-Hoon Cho
Enhancing the fluorescence intensity of colloidal quantum dots (QDs) in case of color-conversion type QD light-emitting devices (LEDs) is very significant due to the large loss of QDs and their quantum yields during fabrication processes, such as patterning and spin-coating, and can therefore improve cost-effectiveness. Understanding the enhancement process is crucial for the design of metallic nanostructure substrates for enhancing the fluorescence of colloidal QDs. In this work, improved color conversion of colloidal green and red QDs coupled with aluminum (Al) and silver (Ag) nanodisk (ND) arrays designed by in-depth systematic finite-difference time domain simulations of excitation, spontaneous emission, and quantum efficiency enhancement is reported...
November 9, 2017: Small
Si Zhang, Yuzhang Liang, Qiang Jing, Zhenda Lu, Yanqing Lu, Ting Xu
Metal halide perovskite nanocrystals (NCs) as a new kind of promising optoelectronic material have attracted wide attention due to their high photoluminescence (PL) quantum yield, narrow emission linewidth and wideband color tunability. Since the PL intensity always has a direct influence on the performance of optoelectronic devices, it is of vital importance to improve the perovskite NCs' fluorescence emission efficiency. Here, we synthesize three inorganic perovskite NCs and experimentally demonstrate a broadband fluorescence enhancement of perovskite NCs by exploiting plasmonic nanostructured surface consisting of nanogrooves array...
November 7, 2017: Scientific Reports
Igor O Koshevoy, Andrey Belyaev, Toni Eskelinen, Thuy Minh Dau, Yana Yu Ershova, Alexei S Melnikov, Sergey P Tunik, Pipsa Hirva
The series of cyanide-bridged coordination polymers [(P2)CuCN]n (1), [(P2)Cu{M(CN)2}]n (M = Cu 3, Ag 4, Au 5) and molecular tetrametallic clusters [{(P4)MM´(CN)}2]2+ (MM´ = Cu2 6, Ag2 7, AgCu 8, AuCu 9, AuAg 10) were obtained using the bidentate P2 and tetradentate P4 phosphane ligands. All title complexes were crystallographically characterized to reveal zig-zag chain arrangement for 1 and 3-5, while 6-10 possess metallocyclic frameworks with different degree of metal-metal bonding. The d10-d10 interactions were evaluated by QTAIM computational approach...
November 8, 2017: Chemistry: a European Journal
Enxian Shi, Wenlong Zhang, Yaqin Zhao, Binsheng Yang
Centrins are Ca(2+)-binding proteins found throughout eukaryotic organisms. Xeroderma pigmentosum group C protein (XPC), a dominant component of the nuclear excision repair (NER) pathway, is a critical target protein of centrins. A 22-residue peptide (K842-R863) from XPC was used to investigate the effect of metal ions (Ca(2+) and Tb(3+)) on the peptide binding of Euplotes octocarinatus centrin (EoCen) by isothermal titration calorimetry (ITC) and fluorescence spectroscopy. ITC and tryptophan spectrofluorimetric titrations revealed that metal ions (Ca(2+) and Tb(3+)) could enhance the affinity between EoCen and the XPC peptide, and the enhanced effects were closely related to the ion potential of metal ions...
November 8, 2017: Metallomics: Integrated Biometal Science
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