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Surface plasmon resonance

Xinxing Zhou, Lijuan Sheng, Xiaohui Ling
In this work, we theoretically propose an optical biosensor (consists of a BK7 glass, a metal film, and a graphene sheet) based on photonic spin Hall effect (SHE). We establish a quantitative relationship between the spin-dependent shift in photonic SHE and the refractive index of sensing medium. It is found that, by considering the surface plasmon resonance effect, the refractive index variations owing to the adsorption of biomolecules in sensing medium can effectively change the spin-dependent displacements...
January 19, 2018: Scientific Reports
Xiaorong Zhang, Aysu Yarman, Júlia Erdossy, Sagie Katz, Ingo Zebger, Katharina J Jetzschmann, Zeynep Altintas, Ulla Wollenberger, Róbert E Gyurcsányi, Frieder W Scheller
Molecularly imprinted polymer (MIP) nanofilms for transferrin (Trf) have been synthesized on gold surfaces by electro-polymerizing the functional monomer scopoletin in the presence of the protein target or around pre-adsorbed Trf. As determined by atomic force microscopy (AFM) the film thickness was comparable with the molecular dimension of the target. The target (re)binding properties of the electro-synthesized MIP films was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV) through the target-binding induced permeability changes of the MIP nanofilms to the ferricyanide redox marker, as well as by surface plasmon resonance (SPR) and surface enhanced infrared absorption spectroscopy (SEIRAS) of the immobilized protein molecules...
January 9, 2018: Biosensors & Bioelectronics
S Centi, F Ratto, F Tatini, S Lai, R Pini
BACKGROUND: Gold nanorods (GNRs) display unique capacity to absorb and scatter near infrared light, which arises from their peculiar composition of surface plasmon resonances. For this reason, GNRs have become an innovative material of great hope in nanomedicine, in particular for imaging and therapy of cancer, as well as in photonic sensing of biological agents and toxic compounds for e.g. biomedical diagnostics, forensic analysis and environmental monitoring. As the use of GNRs is becoming more and more popular, in all these contexts, there is emerging a latent need for simple and versatile protocols for their modification with targeting units that may convey high specificity for any analyte of interest of an end-user...
January 19, 2018: Journal of Nanobiotechnology
Chuanhui Zhu, Qun Xu
The discovery of localized surface plasmon resonances (LSPR) in semiconductor nanocrystals has initiated a new field in plasmonics. And plasmonic nanocrystals of crystal materials have gained rapid development in the past years with a class of materials with unique photoelectronic properties. Present now a growing number of amorphous plasmonic materials are steadily capturing scientific interest of people, though only a few are well-characterized. Here, we focus on the recent development in state-of-the art experiments, and explore the vast library of plasmonic properties in amorphous materials, including their application fields and optical spectral range...
January 19, 2018: Chemistry, An Asian Journal
Lin Chen, Xianmin Ke, Huijie Guo, Junhao Li, Xun Li, Lei Zhou
Although metamaterials wave-plates have been demonstrated previously, many of them suffer from the issue of narrow bandwidth since they typically rely on resonance principles and thus exhibit inevitable frequency dispersions. Here, we show that the dispersion of spoof surface plasmon (SSP) mode supported by a fishbone structure can be freely modulated by varying the structural parameters. This motivates us to establish a general strategy of building broadband wave-plates by cascading two fishbone structures with different propagation constants of SSP modes...
January 18, 2018: Scientific Reports
Chihun In, Sangwan Sim, Beom Kim, Hyemin Bae, Hyunseung Jung, Woosun Jang, Myungwoo Son, Jisoo Moon, Maryam Salehi, Seung Young Seo, Aloysius Soon, Moon-Ho Ham, Hojin Lee, Seongshik Oh, Dohun Kim, Moon-Ho Jo, Hyunyong Choi
Understanding the mutual interaction between electronic excitations and lattice vibrations is key for electronic transport and optoelectronic phenomena. Dynamic manipulation of such interaction is elusive as it requires varying the material composition on the atomic level. In turn, recent studies on topological insulators (TIs) have revealed the coexistence of a strong phonon resonance and topologically protected Dirac plasmon, both in the terahertz (THz) frequency range. Here, using these intrinsic characteristics of TIs, we demonstrate a new methodology for controlling electron-phonon interaction by lithographically engineered Dirac surface plasmons in the Bi2Se3 TI...
January 18, 2018: Nano Letters
Neerugatti KrishnaRao Eswar, Sangeeta Adhikari, Praveen C Ramamurthy, Giridhar Madras
The present work demonstrates an extremely proficient and robust study of efficient interfacial charge transfer through plasmonic Ag decorated Bi2O3 hierarchical photoanodes for the photoelectrochemical treatment of chlorinated phenols. Unique 2D flake-like Bi2O3 hierarchical nanostructures were grown onto a fluorine-doped tin oxide (FTO) substrate by a simple chemical bath deposition method using triethanolamine as complexing agent. The formation of Bi2O3 on FTO was governed by the decomposition of a nucleated bismuth-hydroxyl complex (Bi2O1-x(OH)x) and modification to the electrode was carried out by the deposition of Ag via a chemical reduction method using hydrazine hydrate...
January 18, 2018: Physical Chemistry Chemical Physics: PCCP
Yoonho Choi, Sehyeon Kang, Song-Hyun Cha, Hyun-Seok Kim, Kwangho Song, You Jeong Lee, Kyeongsoon Kim, Yeong Shik Kim, Seonho Cho, Youmie Park
A green synthesis of gold and silver nanoparticles is described in the present report using platycodon saponins from Platycodi Radix (Platycodon grandiflorum) as reducing agents. Platycodin D (PD), a major triterpenoidal platycodon saponin, was enriched by an enzymatic transformation of an aqueous extract of Platycodi Radix. This PD-enriched fraction was utilized for processing reduction reactions of gold and silver salts to synthesize gold nanoparticles (PD-AuNPs) and silver nanoparticles (PD-AgNPs), respectively...
January 17, 2018: Nanoscale Research Letters
Rui Zhu, Xuannan Wu, Yidong Hou, Gaige Zheng, Jianhua Zhu, Fuhua Gao
Optical diode-like effect has sparked growing interest in recent years due to its potential applications in integrated photonic systems. In this paper, we propose and numerically demonstrate a new type of easy-processing metal/dielectric cylinder composite grating on semi-sphere substrate, which can achieve high-contrast asymmetric transmission of unpolarized light for the sum of all diffraction modes in the entire visible region, and effectively guide the diffraction light transmitting out the substrate. The asymmetric light transmission (ALT) ratio is larger than 2 dB in the waveband from 380 nm to 780 nm and the maximum ALT ratio can reach to 13 dB at specified wavelengths...
January 17, 2018: Scientific Reports
Ying Zhang, Chengliang Yang, Bin Xue, Zenghui Peng, Zhaoliang Cao, Quanquan Mu, Li Xuan
We demonstrated flower-like 3D Ag-Au hetero-nanostructures on an indium tin oxide glass (ITO glass) for surface enhanced Raman scattering (SERS) applications. The flower-like 3D Ag nanostructures were obtained through electrodeposition with liquid crystalline soft template which is simple, controllable and cost effective. The flower-like 3D Ag-Au hetero-nanostructures were further fabricated by galvanic replacement reaction of gold (III) chloride trihydrate (HAuCl4·3H2O) solution and flower-like Ag. The flower-like Ag-Au hetero-nanostructure exhibited stronger SERS effects and better chemical stability compared with flower-like Ag nanostructure...
January 17, 2018: Scientific Reports
Anumol Sugathan, Biswajit Bhattacharyya, V V Ravi Kishore, Abhinav Kumar, Guru Pratheep Rajasekar, D D Sarma, Anshu Pandey
While several potential applications of CuFeS2 quantum dots have already been reported, doubts regarding their optical and physical properties persist. In particular, it is unclear if the quantum dot material is metallic, a degenerately doped semiconductor or else an intrinsic semiconductor material. Here we examine the physical properties of CuFeS2 quantum dots in order to address this issue. Specifically, we study the bump that is observed in the optical spectra of these quantum dots at ~500 nm. Using a combination of structural and optical characterization methods, ultrafast spectroscopy, as well as electronic structure calculations, we ascertain that the unusual purple color of CuFeS2 quantum dots as well the golden luster of CuFeS2 films arise from the existence of a plasmon resonance in these materials...
January 17, 2018: Journal of Physical Chemistry Letters
H-H Kung, S Maiti, X Wang, S-W Cheong, D L Maslov, G Blumberg
Using polarization-resolved resonant Raman spectroscopy, we explore collective spin excitations of the chiral surface states in a three dimensional topological insulator, Bi_{2}Se_{3}. We observe a sharp peak at 150 meV in the pseudovector A_{2} symmetry channel of the Raman spectra. By comparing the data with calculations, we identify this peak as the transverse collective spin mode of surface Dirac fermions. This mode, unlike a Dirac plasmon or a surface plasmon in the charge sector of excitations, is analogous to a spin wave in a partially polarized Fermi liquid, with spin-orbit coupling playing the role of an effective magnetic field...
September 29, 2017: Physical Review Letters
Hai-Xia Zhang, Yang Li, Min-Yu Li, Huabin Zhang, Jian Zhang
High-performance catalysts for electrocatalytic and photoelectrochemical water splitting hold great promise for renewable energy conversion and storage. Herein, using porous N-doped carbon supported Au nanoparticles as catalysts, we demonstrate that the photon-induced localized surface plasmon resonance (LSPR) excitation on Au nanoparticles dramatically improves the hydrogen evolution reaction (HER), leading to a more than 4-fold increase of current and meanwhile affording a markedly decreased overpotential of 99 mV at a current density of 10 mA cm-2...
January 17, 2018: Nanoscale
A V Svirid, P V Ershov, E O Yablokov, L A Kaluzhskiy, Yu V Mezentsev, A V Florinskaya, T A Sushko, N V Strushkevich, A A Gilep, S A Usanov, A E Medvedev, A S Ivanov
Thromboxane synthase (TBXAS1) catalyzes the isomerization reaction of prostaglandin H2 producing thromboxane A2, the autocrine and paracrine factor in many cell types. A high activity and metastability by these arachidonic acid derivatives suggests the existence of supramolecular structures that are involved in the regulation of the biosynthesis and directed translocation of thromboxane to the receptor. The objective of this study was to identify TBXAS1 protein partners from human liver tissue lysate using a complex approach based on the direct molecular fishing technique, LC-MS/MS protein identification, and protein-protein interaction validation by surface plasmon resonance (SPR)...
October 2017: Acta Naturae
Roxana Jalili, Joe Horecka, James R Swartz, Ronald W Davis, Henrik H J Persson
Proximity ligation assay (PLA) is a powerful tool for quantitative detection of protein biomarkers in biological fluids and tissues. Here, we present the circular proximity ligation assay (c-PLA), a highly specific protein detection method that outperforms traditional PLA in stringency, ease of use, and compatibility with low-affinity reagents. In c-PLA, two proximity probes bind to an analyte, providing a scaffolding that positions two free oligonucleotides such that they can be ligated into a circular DNA molecule...
January 16, 2018: Proceedings of the National Academy of Sciences of the United States of America
Tomoe Kitao, Francois Lepine, Seda Babloudi, Frederick Walte, Stefan Steinbacher, Klaus Maskos, Michael Blaesse, Michele Negri, Michael Pucci, Bob Zahler, Antonio Felici, Laurence G Rahme
New approaches to antimicrobial drug discovery are urgently needed to combat intractable infections caused by multidrug-resistant (MDR) bacteria. Multiple virulence factor regulator (MvfR or PqsR), a Pseudomonas aeruginosa quorum sensing transcription factor, regulates functions important in both acute and persistent infections. Recently identified non-ligand-based benzamine-benzimidazole (BB) inhibitors of MvfR suppress both acute and persistent P. aeruginosa infections in mice without perturbing bacterial growth...
January 16, 2018: MBio
Yasutaka Kitahama, Tamitake Itoh, Toshiaki Suzuki
To evaluate the shape of an Ag tip with regard to tip-enhanced Raman scattering (TERS) signal, the enhanced electromagnetic (EM) field and scattering spectrum, arising from surface plasmon resonance at the apex of the tip, were calculated using a finite-difference time domain (FDTD) method. In the calculated forward scattering spectra from the smooth Ag tip, the band appeared within the visible region, similar to the experimental results and calculation for a corrugated Ag cone. In the FDTD calculation of TERS, the Ag tip acting as a monopole antenna was adopted by insertion of a perfect electric conductor between the root of the tip and a top boundary surface of the calculation space...
January 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Yahui Zhang, Lin Wang, Xiang Xu, Fang Li, Qingsheng Wu
AIM: The combined efficacy of CuO nanoparticles (NPs) with 22 kinds of antibiotics against Escherichia coli was systematic studied, and CuO with cephalexin synergistic system was screened out. METHODS: Antimicrobial susceptibility test included disk diffusion test, checkerboard method and time-kill assay. The interactions of CuO NPs and antibiotics were analyzed by x-ray photoelectron spectroscopy, Fourier transform infrared spectra and Zeta. The interactions between bacteria and antibacterial agents were studied by surface plasmon resonance sensor for the first time...
January 17, 2018: Nanomedicine
Ho-Pan Hsia, Yin-Hua Yang, Wun-Chung Szeto, Benjamin E Nilsson, Chun-Yeung Lo, Andy Ka-Leung Ng, Ervin Fodor, Pang-Chui Shaw
The influenza virus RNA genome is transcribed and replicated in the context of the viral ribonucleoprotein (vRNP) complex by the viral RNA polymerase. The nucleoprotein (NP) is the structural component of the vRNP providing a scaffold for the viral RNA. In the vRNP as well as during transcription and replication the viral polymerase interacts with NP but it is unclear which parts of the polymerase and NP mediate these interactions. Previously the C-terminal '627' domain (amino acids 538-693) of PB2 was shown to interact with NP...
2018: PloS One
Haibin Zhang, Chunlin Guan, Ning Song, Yuanyuan Zhang, Hong Liu, Jingzhong Fang
Herein, we present an effective bottom-up strategy to fabricate unprecedented macroscopic two-dimensional (2D) plasmonic gold superlattices composed of high-index faceted gold nanocrystal building blocks (NBBs) at the air-liquid interface. In this approach, a synergistic electrostatic and layered self-assembly technique was executed using unique icosidodecahedral gold nanocrystals. It showed that centimeter-squared areas of close-packed monolayer films were formed, and the interparticle spacing of neighbouring Au NBBs could be facilely manipulated from hundreds to several nanometers...
January 16, 2018: Physical Chemistry Chemical Physics: PCCP
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