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Surface plasmon resonance

Chansik Yang, Sugyeong Kwon, Se-Jong Kim, Minseon Jeong, Ji-Young Park, Dongeun Park, Soon Jun Hong, Jong-Wha Jung, Chungho Kim
Cardiovascular disease, which is caused by unregulated platelet aggregation, is one of the main causes of deaths worldwide. Many studies have focused on natural products with antiplatelet effects as a safe alternative therapy in order to prevent the disease. In this context, an in-house chemical library was screened to find natural products capable of inhibiting the interaction between platelet integrin αIIbβ3 and fibrinogen, which is an essential step in platelet aggregation. On the basis of the screening results, indothiazinone, an alkaloid found in microbial cultures, was identified as a potential antiplatelet agent...
April 22, 2017: Chemical Biology & Drug Design
Stefano Stassi, Alessandro Chiadò, Giuseppe Calafiore, Gianluca Palmara, Stefano Cabrini, Carlo Ricciardi
Fano resonance refers to an interference between localized and continuum states that was firstly reported for atomic physics and solid-state quantum devices. In recent years, Fano interference gained more and more attention for its importance in metamaterials, nanoscale photonic devices, plasmonic nanoclusters and surface-enhanced Raman scattering (SERS). Despite such interest in nano-optics, no experimental evidence of Fano interference was reported up to now for purely nanomechanical resonators, even if classical mechanical analogies were referred from a theoretical point of view...
April 21, 2017: Scientific Reports
Wuyun Shang, Fajun Xiao, Weiren Zhu, Hongsen He, Malin Premaratne, Ting Mei, Jianlin Zhao
Being an enabling technology for applications such as ultrasensitive biosensing and surface enhanced spectroscopy, enormous research interests have been focused on further boosting the local field enhancement at Fano resonance. Here, we demonstrate a plasmonic Fano resonance resulting from the interference between a narrow magnetic dipole mode and a broad electric dipole mode in a split-ring resonator (SRR) coupled to a nanoarc structure. Strikingly, when subjected to an azimuthally polarized beam (APB) excitation, the intensity enhancement becomes more than 60 times larger than that for a linearly polarized beam (LPB)...
April 21, 2017: Scientific Reports
Xiaolin Kang, Qifeng Ruan, Han Zhang, Feng Bao, Jun Guo, Minghua Tang, Si Cheng, Jianfang Wang
Concave nanocrystals usually exhibit a large electromagnetic-field enhancement and superior catalytic performance due to their sharp corners, negative curvature and high-index facets. Conventional gold bipyramids (AuBPs) possess intriguing plasmonic properties which are attractive for various applications while the surface curvature of the reported bipyramids has not been fine-tuned to concave or convex structures to date. Additionally, the longitudinal surface plasmon resonance (LSPR) wavelengths of conventional AuBPs are mostly located in the range of 650-1350 nm and the sizes of these nanoparticles are usually not beyond 350 nm, which are not facilitated to some nano-focusing and nanophotonic applications...
April 21, 2017: Nanoscale
Jeeban Kumar Nayak, Rajan Jha
A graphene-based surface plasmon resonance sensor using D-shaped fiber in anti-crossing has been designed. Silver as a plasmon active metal is followed by graphene, which helps in preventing oxidation and shows better adsorption efficiency to biomolecules. A wavelength interrogation technique based on the finite element method has been used to evaluate performance parameters. Design parameters such as thickness of silver, residual cladding, and GeO<sub>2</sub> dopant concentration have been optimized...
April 20, 2017: Applied Optics
Andrea E Schlather, Alejandro Manjavacas, Adam Lauchner, Valeria Spolon Marangoni, Christopher J DeSantis, Peter Nordlander, Naomi J Halas
There is currently a worldwide need to develop efficient photocatalytic materials that can reduce the high energy cost of common industrial chemical processes. One possible solution focuses on metallic nanoparticles (NPs) that can act as efficient absorbers of light due to their surface plasmon resonance. Recent work indicates that small NPs, when photoexcited, may allow for efficient electron or hole transfer necessary for photocatalysis. Here we investigate the mechanisms behind hot hole carrier dynamics by studying the photo-driven oxidation of citrate ions on Au@SiO2@Au core-shell nanoparticles...
April 20, 2017: Journal of Physical Chemistry Letters
Vincenzo Amendola, Roberto Pilot, Marco Frasconi, Onofrio M Maragò, Maria Antonia Iatì
In the last two decades, plasmon resonance in gold nanoparticles (Au NPs) has been the subject of intense research efforts. Plasmon physics is intriguing and its precise modelling proved to be challenging. In fact, plasmons are highly responsive to a multitude of factors, either intrinsic to the Au NPs or from the environment, and recently the need emerged for the correction of standard electromagnetic approaches with quantum effects. Applications related to plasmon absorption and scattering in Au NPs are impressively numerous, ranging from sensing to photothermal effects to cell imaging...
May 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Hirokazu Tanoue, Norifumi L Yamada, Kohzo Ito, Hideaki Yokoyama
Polymer brush formation kinetics was measured by quartz crystal microbalance (QCM). In the QCM measurement anomalous complex frequency shift as a function of graft density was observed: dissipation rate shift ΔΓ first increased, showed a peak and then decreased despite the graft density of the polymer brush was increasing monotonically. We calculated the shear modulus of the brush layer from the measured complex frequency shift and revealed that the peak of ΔΓ described the crossover from a viscous brush layer to elastic brush layer...
April 20, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
A Le Beulze, S Gomez-Graña, H Gehan, S Mornet, S Ravaine, M Correa-Duarte, L Guerrini, R A Alvarez-Puebla, E Duguet, E Pertreux, A Crut, P Maioli, F Vallée, N Del Fatti, O Ersen, M Treguer-Delapierre
Raspberry-like nano-objects made of large plasmonic satellites (>10 nm) covering a central dielectric particle have many potential applications as photonic materials, superlenses and (bio-) sensors, but their synthesis remains challenging. Herein, we show how to build stable and robust raspberry-like nano-systems with close-packed satellites, by combining monodisperse silica particles (80 or 100 nm diameter) and oppositely charged noble metal nanoparticles (Au or Ag) with well-defined sizes (10-50 nm). The spectral characteristics of their associated plasmonic resonances (wavelength, linewidth, extinction cross-section) and the electromagnetic coupling between satellites were observed using the spatial modulation spectroscopy technique and interpreted through a numerical model...
April 20, 2017: Nanoscale
Ovidio Peña-Rodríguez, Alejandro Prada, José Olivares, Alicia Oliver, Luis Rodríguez-Fernández, Héctor G Silva-Pereyra, Eduardo Bringa, José Manuel Perlado, Antonio Rivera
In this work we have studied the elongation of silver nanoparticles irradiated with 40 MeV Bromine ions by means of in situ optical measurements, transmission electron microscopy and molecular dynamics simulations. The localized surface plasmon resonance of silver nanoparticles has a strong dependence on the particle shape and size, which allowed us to obtain the geometrical parameters with remarkable accuracy by means of a fit of the optical spectra. Optical results have been compared with transmission electron microscopy images and molecular dynamics simulations and the agreement is excellent in both cases...
April 19, 2017: Scientific Reports
Ravi Kant, Rana Tabassum, Banshi D Gupta
Caffeine is the most popular psychoactive drug consumed in the world for improving alertness and enhancing wakefulness. However, caffeine consumption beyond limits can result in lot of physiological complications in human beings. In this work, we report a novel detection scheme for caffeine integrating nanohybrid membranes of reduced graphene oxide (rGO) in chitosan modified silica sol gel (rGO: chitosan: silica sol gel) with fiber optic surface plasmon resonance. The chemically synthesized nanohybrid membrane forming the sensing route has been dip coated over silver coated unclad central portion of an optical fiber...
May 12, 2017: Nanotechnology
Si Chen, Zhiwei Feng, Yun Wang, Shifan Ma, Ziheng Hu, Peng Yang, Yifeng Chai, Xiang-Qun Sean Xie
Tumor Necrosis Factor alpha (TNF-α) is overexpressed in various diseases, and it has been a validated therapeutic target for autoimmune diseases. All therapeutics currently used targeting TNF-α are biomacromolecules, and limited numbers of TNF-α chemical inhibitors have been reported, which makes the identification of small molecule alternatives in urgent need. Recent studies mainly focused on identifying small molecules that directly bind to TNF-α or TNF receptor-1 (TNFR1), and/or inhibit the interaction between TNF-α and TNFR1, and/or regulate related signaling pathways...
April 19, 2017: Journal of Chemical Information and Modeling
X-L Wu, H Wu, Z-M Wang, H Aizawa, J Guo, Y-H Chu
Herein, debris particulates of nanoporous silver (np-Ag) were synthesised by a dealloying method, and their integration behaviour and surface-enhanced Raman scattering (SERS) properties during iodine functionalisation were examined. It was found that the dealloyed np-Ag debris particulates gradually assembled to form rigid nanoporous microspheres comprising Ag nano-ligaments due to mechanical collisions during iodine treatment. High-resolution transmission electron microscopy and X-ray photoelectron microscopy clearly showed the iodide surface of np-Ag, which was dotted with iodine or iodide 'nanoislands'...
April 19, 2017: Scientific Reports
Stanislav Melnik, A-C Neumann, R Karongo, S Dirndorfer, Martin Stübler, Verena Ibl, R Niessner, Dietmar Knopp, Eva Stoger
Antibody MC10E7 is one of a small number of monoclonal antibodies that bind specifically to [Arg4]-microcystins and it can be used to survey natural water sources and food samples for algal toxin contamination. However, the development of sensitive immunoassays in different test formats, particularly user-friendly tests for on-site analysis, requires a sensitive but also cost-effective antibody. The original version of MC10E7 was derived from a murine hybridoma, but we determined the sequence of the variable regions using the peptide mass-assisted cloning strategy and expressed a scFv (single-chain variable fragment) format of this antibody in yeast and a chimeric full size version in leaves of Nicotiana tabacum and N...
April 19, 2017: Plant Biotechnology Journal
David P Hoogerheide, Sergei Y Noskov, Daniel Jacobs, Lucie Bergdoll, Vitalii Silin, David L Worcester, Jeff Abramson, Hirsh Nanda, Tatiana K Rostovtseva, Sergey M Bezrukov
Dimeric tubulin, an abundant water-soluble cytosolic protein known primarily for its role in the cytoskeleton, is routinely found to be associated with mitochondrial outer membranes, although the structure and physiological role of mitochondria-bound tubulin are still unknown. There is also no consensus on whether tubulin is a peripheral membrane protein or is integrated into the outer mitochondrial membrane. Here the results of five independent techniques-surface plasmon resonance, electrochemical impedance spectroscopy, bilayer overtone analysis, neutron reflectometry, and molecular dynamics simulations-suggest that α-tubulin's amphipathic helix H10 is responsible for peripheral binding of dimeric tubulin to biomimetic "mitochondrial" membranes in a manner that differentiates between the two primary lipid headgroups found in mitochondrial membranes, phosphatidylethanolamine and phosphatidylcholine...
April 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
David M Fryauf, Juan Jose Diaz Leon, Andrew C Phillips, Nobuhiko Paul Kobayashi
Silver thin films covered with dielectric films serving as protective coatings are desired for telescope mirrors, but durable coatings have proved elusive. As part of an effort to develop long-lived protected-silver mirrors, silver thin films were deposited by electron beam evaporation using a physical vapor deposition system at the University of California Observatories Astronomical Coatings Lab. The silver films were later covered with a stack of dielectric films utilizing silicon nitride and titanium dioxide deposited by ion assisted electron beam evaporation to fabricate protected mirrors...
April 18, 2017: ACS Applied Materials & Interfaces
Zheng Zeng, Xiaojun Shi, Taylor Mabe, Shaun Christie, Grant Gilmore, Adam W Smith, Jianjun Wei
A novel plasmonic nanoledge device was presented to explore the geometry-induced trapping of nanoscale biomolecules and examine a generation of surface plasmon resonance (SPR) for plasmonic sensing. To design an optimal plasmonic device, a semi-analytical model was implemented for a quantitative analysis of SPR under plane-wave illumination and a finite-difference time-domain (FDTD) simulation was used to study the optical transmission and refractive index (RI) sensitivity. In addition, total internal reflection fluorescence (TIRF) imaging was used to visualize the migration of fluorescently labeled bovine serum albumin (BSA) into the nanoslits; and fluorescence correlation spectroscopy (FCS) was further used to investigate the diffusion of BSA in the nanoslits...
April 18, 2017: Analytical Chemistry
Joji Tanaka, Anne S Gleinich, Qiang Zhang, Richard Whitfield, Kristian Kempe, David M Haddleton, Thomas P Davis, Sébastien Perrier, Daniel A Mitchell, Paul Wilson
A range of glycopolymers composed of N-acetylgalactosamine were prepared via sequential Cu(I)-mediated polymerization and alkyne-azide click (CuAAC). The resulting polymers were shown, via multichannel surface plasmon resonance, to interact specifically with human macrophage galactose lectin (MGL; CD301) with high affinity (KD = 1.11 μM), but they did not bind to the mannose/fucose-selective human lectin dendritic-cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN; CD209). The effect of sugar ligand valency on the binding (so-called "glycoside cluster effect") of poly(N-acetylgalactosamine) to MGL was investigated by varying first the polymer chain length (DP: 100, 64, 40, 23, 12) and then the architecture (4- and 8-arm star glycopolymers)...
April 18, 2017: Biomacromolecules
Jhovani Bornacelli, Carlos Torres-Torres, Hector Silva-Pereyra, Luis Rodriguez-Fernandez, Miguel Avalos-Borja, Juan Cheang-Wong, Alicia Oliver
The authors describe a systematic study about photoluminescence and third order nonlinear ultraviolet properties exhibited by platinum nanoparticles nucleated in a high-purity silica matrix. The modification in the characteristic photoluminescence spectra of the nanocomposites, range between 400 to 600 nm, was obtained by the assistance of a thermal annealing process that changed the average size of the platinum nanoparticles. The influence of temperature between 200-1100 °C during the thermal treatment of the nanostructures was analyzed...
April 18, 2017: Methods and Applications in Fluorescence
Tomáš Špringer, Xue Chadtová Song, Maria Laura Ermini, Josefína Lamačová, Jiří Homola
Functional gold nanoparticles (AuNPs) are commonly used to enhance the response of optical affinity biosensors. In this work, we investigated the effect of preparation conditions on functional properties of AuNPs functionalized with antibody (Ab-AuNPs), specifically AuNPs with antibody against carcinoembryonic antigen (CEA) covalently attached via carboxy-terminated oligo-ethylene thiolate linker layer. The following parameters of preparation of Ab-AuNP have been found to have a significant effect on Ab-AuNP performance in affinity biosensors: the time of reaction of activated AuNPs with antibody, concentrations of antibody and amino-coupling reagents, and composition of immobilization buffer (molarity and salt content)...
April 17, 2017: Analytical and Bioanalytical Chemistry
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