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Surface plasmons

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
Haidan Mao, Yahong Chen, Sergey A Ponomarenko, Ari T Friberg
We develop a general coherent (pseudo)-mode representation of partially coherent surface plasmon polaritons in the Kretschmann excitation geometry. We obtain explicit analytical results for coherent pseudo-modes of narrowband SPPs with Gaussian spectra and spectral correlations. We also evaluate the global degree of coherence of such SPPs which quantifies their overall coherence state within a given spatial domain. Not only will the developed coherent pseudo-mode representation facilitate SPP coherence state characterization, but it will also substantially reduce the computational complexity of the studies of partially coherent SPP interactions with nanoparticles...
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
Elham Karami Keshmarzi, R Niall Tait, Pierre Berini
Single-mode surface plasmon distributed feedback (DFB) lasers are realized in the near infrared using a two-dimensional non-uniform long-range surface plasmon polariton structure. The surface plasmon mode is excited onto a 20 nm-thick, 1 μm-wide metal stripe (Ag or Au) on a silica substrate, where the stripe is stepped in width periodically, forming a 1st order Bragg grating. Optical gain is provided by optically pumping a 450 nm-thick IR-140 doped PMMA layer as the top cladding, which covers the entire length of the Bragg grating, thus creating a DFB laser...
March 14, 2018: Nanoscale
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
Minho Kim, Sung Min Ko, Jae-Myoung Kim, Jiwoong Son, Chungyeon Lee, Won-Kyu Rhim, Jwa-Min Nam
Uniformly controlling a large number of metal nanostructures with a plasmonically enhanced signal to generate quantitative optical signals and the widespread use of these structures for surface-enhanced Raman scattering (SERS)-based biosensing and bioimaging applications are of paramount importance but are extremely challenging. Here, we report a highly controllable, facile selective-interdiffusive dealloying chemistry for synthesizing the dealloyed intra-nanogap particles (DIPs) with a ∼2 nm intragap in a high yield (∼95%) without the need for an interlayer...
February 28, 2018: ACS Central Science
Xuming Sun, Lin Huang, Ru Zhang, Wei Xu, Jingyi Huang, Deepanjali D Gurav, Vadanasundari Vedarethinam, Ruoping Chen, Jiatao Lou, Qian Wang, Jingjing Wan, Kun Qian
Current metabolic analysis is far from ideal to engage clinics and needs rationally designed materials and device. Here we developed a novel plasmonic chip for clinical metabolic fingerprinting. We first constructed a series of chips with gold nanoshells on the surface through controlled particle synthesis, dip-coating, and gold sputtering for mass production. We integrated the optimized chip with microarrays for laboratory automation and micro-/nanoscaled experiments, which afforded direct high-performance metabolic fingerprinting by laser desorption/ionization mass spectrometry using 500 nL of various biofluids and exosomes...
February 28, 2018: ACS Central Science
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
Jukun Liu, Xin Jia, Weishu Wu, Ke Cheng, Donghai Feng, Shian Zhang, Zhenrong Sun, Tianqing Jia
This paper reports the ultrafast imaging on the formation of periodic surface ripples induced by a single 800 nm, 50 fs laser pulse. The evolution process is observed on a Si surface with a prefabricated nanogroove. The ripples emerge very quickly, only 3 ps after the laser pulse with a fluence of 0.18 J/cm2 irradiating on the surface, and last for several hundreds of picoseconds. The ultrafast dynamics of laser-matter interaction, such as free carrier excitation, carrier and lattice heating, surface plasmon polariton (SPP) excitation, etc, are studied theoretically...
March 5, 2018: Optics Express
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