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Surface plasmon resonance

Yuriy Akimov
This Letter revises the resonance theory of Kretschmann and Otto configurations, where enhanced electromagnetic fields and strong reflectance dips observed under total internal reflection are conventionally attributed to the resonance on surface plasmon-polaritons, the subsystem eigenwaves supported by a single metal/dielectric interface. The rigorous mathematical analysis demonstrates that the field enhancement and reflection decrease, in fact, are two independent physical phenomena that occur under different conditions...
March 15, 2018: Optics Letters
Peng Chen, Xiaohu Liu, Garima Goyal, Nhung Thi Tran, James Chin Shing Ho, Yi Wang, Daniel Aili, Bo Liedberg
Localized surface plasmon resonance (LSPR) constitutes a versatile technique for biodetection exploiting the sensitivity of plasmonic nanostructures to small changes in refractive index. The optical shift in the LSPR band caused by molecular in-teractions in the vicinity of the nanostructures are typically < 5 nm and can readily be detected using a spectrophotometer. Widespread use of LSPR based sensors require cost effective devices and would benefit from sensing schemes that enables use of very simple spectrophotometers or even naked eye detection...
March 15, 2018: Analytical Chemistry
Yan Zhan, Yingliang Liu, Hongru Zu, Yanxian Guo, Shuangshuang Wu, Haiyao Yang, Zhiming Liu, Bingfu Lei, Jianle Zhuang, Xuejie Zhang, Di Huang, Chaofan Hu
Different from their bulk counterparts, plasmonic molybdenum oxide nanomaterials display superior optical and electronic properties, but unfortunately, phase-controlled synthesis of molybdenum oxide nanomaterials with multifunctional performances still remains a challenge. To actualize this, a surfactant-free solvothermal strategy was proposed to fabricate molybdenum oxide nanomaterials with a tunable phase. Encouragingly, the as-prepared molybdenum dioxide nanoparticles (MoO2 NPs) exhibit intense near-infrared (NIR) absorption attributed to the localized surface plasmon resonance (LSPR) effect, which results in their application as a surface enhanced Raman scattering (SERS) substrate to detect trace amounts of molecular species including Rhodamine 6G (R6G), crystal violet (CV), IR-780 iodide (IR780) and methylene blue (MB)...
March 15, 2018: Nanoscale
Wei Wang
Nanomaterials exhibit structural and functional heterogeneity among individual nanoparticles, thus requiring a capability to study single nanoparticles. While electron microscopes often provide static images of their chemical composition, morphology and structure, imaging the chemical activity of single nanoparticles is highly desirable for exploring the structure-activity relationship via a bottom-up strategy, to understand their microscopic reaction mechanisms and kinetics, and to identify a minority subpopulation with extraordinary activity...
March 15, 2018: Chemical Society Reviews
Emily G Westbrook, Peng Zhang
We report the localized surface plasmon resonance (LSPR)-enhanced triplet-triplet annihilation upconversion (TTA-UC) of polymeric acceptors containing high percentages of acceptor units. A poly[(methyl methacrylate)-co-(glycidyl methacrylate)] copolymer series with increasing glycidyl methacrylate ratio was prepared using reversible addition-fragmentation chain transfer (RAFT) polymerization. After post-modification of the glycidyl group with anthracene, the acceptor unit, a series of poly[(methyl methacrylate)-co-(2-hydroxypropyl-9-anthroate methacrylate)] (polyACA) was produced with different numbers of acceptor units...
March 15, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Enrico Della Gaspera, Enrico Menin, Gianluigi Maggioni, Cinzia Sada, Alessandro Martucci
Sub-monolayers of monodisperse Au colloids with different surface coverage have been embedded in between two different metal oxide thin films, combining sol-gel depositions and proper substrates functionalization processes. The synthetized films were TiO₂, ZnO, and NiO. X-ray diffraction shows the crystallinity of all the oxides and verifies the nominal surface coverage of Au colloids. The surface plasmon resonance (SPR) of the metal nanoparticles is affected by both bottom and top oxides: in fact, the SPR peak of Au that is sandwiched between two different oxides is centered between the SPR frequencies of Au sub-monolayers covered with only one oxide, suggesting that Au colloids effectively lay in between the two oxide layers...
March 14, 2018: Materials
Jitendra B Maurya, Alexandre François, Yogendra K Prajapati
One-dimensional photonic crystal (1DPC) sensors have emerged as contenders for traditional surface plasmon resonance sensors, owing to their potential for the detection of bigger molecules and particles due to their higher interaction volume in the sensing medium. Two-dimensional layered nanomaterials, most notably graphene and dichalcogenides (e.g., MoS₂, MoSe₂, WS₂, and WSe₂), have shown higher refractive index sensitivity because of their absorption as well as adsorption property. The proposed configuration of 1DPC presented consists of alternate layers of the aforementioned nanomaterials and silicon...
March 14, 2018: Sensors
Gayan S Jayawickrama, Alireza Nematollahi, Guanchen Sun, W Bret Church
Kynurenine aminotransferase-II (KAT-II) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that acts in the tryptophan metabolic pathway by catalyzing the transamination of kynurenine into kynurenic acid (KYNA). It is one of four isoforms in the KAT family, of which it is the primary homologue responsible for KYNA production in the mammalian brain. KAT-II is targeted for inhibition as KYNA is implicated in diseases such as schizophrenia, where it is found in elevated concentrations. Previously, many different approaches have been taken to develop KAT-II inhibitors, and herein fragment-based drug design (FBDD) approaches have been exploited to provide further lead compounds that can be designed into novel inhibitors...
March 1, 2018: SLAS Discovery
A Bar-Ilan, T Livnat, M Hoffmann, L Binder, M Zakar, R Guy, Y Felikman, L Moschcovich, B Shenkman, D Monroe, O Hershkovitz, G Kenet, G Hart
INTRODUCTION: Recombinant FVIIa (rFVIIa) is an effective treatment for haemophilia through frequent administration. However, the short half-life of rFVIIa decreases its prophylactic ability to reduce bleeding. Carboxy-terminal peptide (CTP)-modified FVIIa (MOD-5014) is a long-acting rFVIIa developed for on-demand treatment of haemophilia using either an intravenous or subcutaneous injection with the aim of less frequent administrations, as well as for prophylactic use. AIM: The comprehensive evaluation of the activity MOD-5014 vs commercially available rhFVIIa, as well as their interaction with cofactors and inhibitors...
March 14, 2018: Haemophilia: the Official Journal of the World Federation of Hemophilia
Yakai Song, Linjuan Li, Yantao Chen, Jingqiu Liu, Senhao Xiao, Fulin Lian, Naixia Zhang, Hong Ding, Yuanyuan Zhang, Kaixian Chen, Hualiang Jiang, Chenhua Zhang, Yu-Chih Liu, Shijie Chen, Cheng Luo
DOT1L (the disruptor of telomeric silencing 1-like), through its methyltransferase activity of H3K79, plays essential roles in transcriptional regulation, cell cycle regulation, and DNA damage response. In addition, DOT1L is believed to be involved in the development of MLL-rearranged leukemia driven by the MLL (mixed-lineage leukemia) fusion proteins, which thus to be a crucial target for leukemia therapy. Hence, discovering of novel DOT1L inhibitors has been in a great demand. In this study, we initiated the discovering process from setting up the AlphaLISA based High Throughput Screening (HTS) assay of DOT1L...
February 24, 2018: Bioorganic & Medicinal Chemistry
Diana David, Arun Surendran, Jissa V Thulaseedharan, Asha S Nair
BACKGROUND: Smurf2 E3 ubiquitin ligase physically associates with and regulate the stability of distinct cellular protein substrates. The multi-functional scaffold protein Connector enhancer of kinase suppressor of ras 2 (CNKSR2) plays a key role in regulating cell proliferation, and differentiation through multiple receptor tyrosine kinase pathways. The aim of this study was to investigate whether the interaction between Smurf2 and CNKSR2 has any significant role in the post transcriptional regulation of CNKSR2 expression in breast cancer...
March 13, 2018: BMC Cancer
Md Zakir Hossain, Susan P McCormick, Chris M Maragos
A sensitive, rapid, and reproducible imaging surface plasmon resonance (iSPR) biosensor assay was developed to detect T-2 toxin and T-2 toxin-3-glucoside (T2-G) in wheat. In this competitive assay, an amplification strategy was used after conjugating a secondary antibody (Ab₂) with gold nanoparticles. Wheat samples were extracted with a methanol/water mixture (80:20 v/v), then diluted with an equal volume of primary antibody (Ab₁) for analysis. Matrix-matched calibration curves were prepared to determine T-2 toxin and T2-G...
March 10, 2018: Toxins
Cecilia Augustsson, Anders Svensson, Birgitte Kjaer, Tzu-Yuan Chao, Xia Wenjuan, Berit Olsen Krogh, Jens Breinholt, Jes Thorn Clausen, Ida Hilden, Helle Heibroch Petersen, Lars Christian Petersen
BACKGROUND: Initiation of coagulation is induced by binding of activated factor VII (FVIIa) to tissue factor (TF) and activation of factor X (FX) in a process regulated by tissue factor pathway inhibitor (TFPI). TFPI contains three Kunitz-type protease inhibitor domains (K1-K3) of which K1 and K2 block the active sites of FVIIa and FXa respectively. OBJECTIVE: To produce a monoclonal antibody (mAb) directed towards K1, to characterize the binding epitope, and to study its effect on TFPI inhibition...
March 12, 2018: Journal of Thrombosis and Haemostasis: JTH
Jatish Kumar, Hasier Eraña, Elena López-Martínez, Nathalie Claes, Víctor F Martín, Diego M Solís, Sara Bals, Aitziber L Cortajarena, Joaquín Castilla, Luis M Liz-Marzán
Amyloid fibrils, which are closely associated with various neurodegenerative diseases, are the final products in many protein aggregation pathways. The identification of fibrils at low concentration is, therefore, pivotal in disease diagnosis and development of therapeutic strategies. We report a methodology for the specific identification of amyloid fibrils using chiroptical effects in plasmonic nanoparticles. The formation of amyloid fibrils based on α-synuclein was probed using gold nanorods, which showed no apparent interaction with monomeric proteins but effective adsorption onto fibril structures via noncovalent interactions...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Artur Movsesyan, Anne-Laure Baudrion, Pierre-Michel Adam
The optical characterization of a single metallic nanostructure has a strong interest in the scientific community owing to its localized surface plasmon resonances. For a single nano-object, the simplest and the accepted optical characterization technique is dark-field spectroscopy, even if there are many drawbacks and a certain complexity to operate it. We propose here using extinction spectroscopy of nanoparticles ensembles to characterize optically a single nanostructure. The scattering spectrum of a single gold nanocylinder and the extinction spectrum of a well-chosen array show similar results...
March 5, 2018: Optics Express
Lei Lei, Shun Li, Haixuan Huang, Keyu Tao, Ping Xu
We propose a design of an ultra-broadband absorber based on a thin metamaterial nanostructure composed of a periodic array of titanium-silica (Ti-SiO2 ) cubes and an aluminum (Al) bottom film. The proposed structure can achieve nearly perfect absorption with an average absorbance of 97% spanning a broad range from visible to near-infrared (i.e., from 354 nm to 1066 nm), showing a 90% absorption bandwidth over 712 nm, and the peak absorption is up to 99.8%. The excitation of superior surface plasmon resonance combined with the resonance induced by the metal-insulator-metal Fabry-Perot (FP) cavity leads to this broadband perfect absorption...
March 5, 2018: Optics Express
Shinpei Ogawa, Masaaki Shimatani, Shoichiro Fukushima, Satoshi Okuda, Kazuhiko Matsumoto
Metal-insulator-metal-based plasmonic metamaterial absorbers (MIM-PMAs) generate strong localized surface plasmon resonance (LSPR) on their surfaces. Therefore, MIM-PMAs are expected to enhance the absorption of graphene coated on their surfaces. Graphene-coated MIM-PMAs (GMIM-PMAs) were developed and their optical properties were investigated both experimentally and numerically at infrared wavelengths. Significant modification of the absorption of GMIM-PMAs was achieved only in the main LSPR wavelength region, where the insulator is lossless...
March 5, 2018: Optics Express
Kristian Tølbøl Sørensen, Charlotte Bonde Ingvorsen, Line Hagner Nielsen, Anders Kristensen
A photonic crystal slab (PCS) sensor is a universal refractive index sensor with possibilities and performance very similar to surface plasmon resonance (SPR), which represents the gold standard of biosensing. Cheap PCS sensors can be made vacuum-free entirely out of polymers, but come with additional challenges, besides those relating to temperature-variations, which must be considered in any refractive index based method: The polymeric waveguide core was found to swell by ∼0.3% as water absorbed into the waveguide core over ∼1...
March 5, 2018: Optics Express
Ognjen Ilic, Nathan H Thomas, Thomas Christensen, Michelle C Sherrott, Marin Soljacic, Austin J Minnich, Owen D Miller, Harry A Atwater
We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative heat transfer, which, when combined with the use of resonant structures, overcomes the intrinsically broadband nature of thermal radiation. In canonical geometries, we use nonlinear optimization to show that stacked graphene sheets offer improved heat conductance contrast between "ON" and "OFF" switching states, but that a >10x higher modulation is achieved between isolated graphene resonators than for parallel graphene sheets...
March 12, 2018: ACS Nano
Yongbing Lou, Yake Zhang, Lin Cheng, Jinxi Chen, Yixin Zhao
he localized surface plasmon resonance (LSPR) effect has been widely utilized in photocatalysis, but most reported LSPR materials are based on noble metals of Au or Ag with high chemical stability. The plasmonic Cu nanoparticles exhibiting LSPR absorbance locating at 600 nm are promising for lots of applications such as photocatalysis. Unfortunately, plasmonic Cu nanoparticles are bothered by their serious surface oxidation in air. Herein, a novel lollipop-shaped Cu@Cu2O/ZnO heterojunction nanostructure was designed, for the first time, to stabilize the plasmonic Cu core by decorating ZnO nanorods onto Cu@Cu2O core-shell structures...
March 12, 2018: ChemSusChem
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