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Yinqiang Xia, Rongxin Su, Renliang Huang, Li Ding, Libing Wang, Wei Qi, Zhimin He
For the analysis of massive samples containing multiple analytes, the enhancement of detection efficiency is crucial. In this study, a facile method was developed for sequential detection of chloramphenicol (CAP) and gentamicin (GEN) in complex samples, e.g. milk, using a surface plasmon resonance (SPR)-based biosensor. Based on the immune inhibition format, two conjugates of antigen and bovine serum albumin (BSA)-denoted as CAP-BSA and GEN-BSA-were grafted on the same channel of the SPR sensor chip. Two standard curves for CAP and GEN were separately obtained by first mixing a single antibody with different concentrations of the relevant antigen...
February 16, 2017: Biosensors & Bioelectronics
Raj Kumar Thapa, Jae Hee Kim, Jee-Heon Jeong, Beom Soo Shin, Han-Gon Choi, Chul Soon Yong, Jong Oh Kim
Combination therapies are widely investigated cancer treatment modalities. Carbon based systems such as graphene oxide (GO), plasmonic nanoparticles such as silver nanoparticles (AgNPs), and the folate analog, methotrexate (MTX), have been separately studied for their potential anticancer effects. In this study, we combined these systems to develop AgNPs-embedded GO with conjugated MTX (MTX-GO/AgNPs) and studied their folate receptor-targeted anticancer effects. Results revealed successful formation of AgNPs on GO along with MTX conjugation as suggested by UV/visible, TEM, AFM, FTIR, and XRD analysis...
February 13, 2017: Colloids and Surfaces. B, Biointerfaces
Fengli Gao, Maozhong Sun, Wei Ma, Xiaoling Wu, Liqiang Liu, Hua Kuang, Chuanlai Xu
Photodynamic therapy (PDT) agent, which generates singlet oxygen ((1) O2 ) under light, has attracted significant attention for its broad biological and medical applications. Here, DNA-driven shell-satellite (SS) gold assemblies as chiral photosensitizers are first fabricated. The chiral plasmonic nanostructure, coupling with cysteine enantiomers on its surface, exhibits intense chiroplasmonic activities (-40.2 ± 2.6 mdeg) in the visible region. These chiral SS nanoassemblies have high reactive oxygen species generating efficiency under circular polarized light illumination, resulting in a (1) O2 quantum yield of 1...
February 23, 2017: Advanced Materials
Min Hu, Ning Cui, Zhixiang Bo, Feixiang Xiang
In this study, we aimed to use different strategies to further uncover the anti-angiogenic molecular mechanism of a fucoidan-like polysaccharide STPC2, isolated from brown alga Sargassum thunbergii. A desulfated derivative, STPC2-DeS, was successfully prepared and identified. The native polysaccharide and desulfated product were subjected to evaluate their anti-angiogenic effects. In the tube formation assay, STPC2 showed dose-dependent inhibition. In addition, STPC2 could distinctly inhibit the permeation of HUVEC cells into the lower chamber...
February 21, 2017: Marine Drugs
Xiao Zhang, Xueqian Li, Du Zhang, Neil Qiang Su, Weitao Yang, Henry O Everitt, Jie Liu
Photocatalysis has not found widespread industrial adoption, in spite of decades of active research, because the challenges associated with catalyst illumination and turnover outweigh the touted advantages of replacing heat with light. A demonstration that light can control product selectivity in complex chemical reactions could prove to be transformative. Here, we show how the recently demonstrated plasmonic behaviour of rhodium nanoparticles profoundly improves their already excellent catalytic properties by simultaneously reducing the activation energy and selectively producing a desired but kinetically unfavourable product for the important carbon dioxide hydrogenation reaction...
February 23, 2017: Nature Communications
Jian Hu, Yun Zhu, Jian-Zhong Zhang, Rong-Guang Zhang, Hou-Min Li
BACKGROUND: Cryopyrin-associated periodic syndrome (CAPS) is a group of rare, heterogeneous autoinflammatory disease characterized by interleukin (IL)-1β-mediated systemic inflammation and clinical symptoms involving skin, joints, central nervous system, and eyes. It encompasses a spectrum of three clinically overlapping autoinflammatory syndromes including familial cold autoinflammatory syndrome, Muckle-Wells syndrome (MWS), and neonatal-onset multisystem inflammatory disease. CAPS is associated with gain-of-function missense mutations in NOD-like receptor family pyrin domain-containing protein 3 (NLRP3), the gene encoding NLRP3...
2017: Chinese Medical Journal
O Bibikova, J Haas, A I López-Lorente, A Popov, M Kinnunen, I Meglinski, B Mizaikoff
We report the preparation and characterization of plasmonic chip-based systems comprising self-assembled gold nanostars at silicon substrates that enable concomitantly enhanced Raman (surface enhanced Raman spectroscopy; SERS) and mid-infrared (surface enhanced infrared reflection or absorption spectroscopy; SEIRA) spectral signatures. The high-aspect-ratio structure of gold nanostars provides an increased number of hot spots at their surface, which results in an electric field enhancement around the nanomaterial...
February 23, 2017: Analyst
Hao Shen, Li Chen, Lorenzo Ferrari, Meng-Hsien Lin, N Asger Mortensen, Shangjr Gwo, Zhaowei Liu
The advances in recent nanofabrication techniques have facilitated explorations of metal structures into nanometer scales, where the traditional local-response Drude model with hard-wall boundary conditions fails to accurately describe their optical responses. The emerging nonlocal effects in single ultrasmall silver nanoparticles have been experimentally observed in single-particle spectroscopy enabled by the unprecedented high spatial resolution of electron energy loss spectroscopy (EELS). However, unambiguous optical observation of such new effects in gold nanoparticles has yet not been reported, due to the extremely weak scattering and the obscuring fingerprint of strong interband transitions...
February 22, 2017: Nano Letters
Grant J Stec, Adam Lauchner, Yao Cui, Peter Nordlander, Naomi J Halas
Polycyclic aromatic hydrocarbon (PAH) molecules, the hydrogen-terminated, subnanometer scale version of graphene, support plasmon resonances with the addition or removal of a single electron. Typically colorless when neutral, they are transformed into vivid optical absorbers in either their positively or negatively charged states. Here we demonstrate a low-voltage, multistate electrochromic device based on PAH plasmon resonances that can be reversibly switched between nearly colorless (0 V), olive (+4 V), and royal blue (-3...
February 22, 2017: ACS Nano
Xiaoying Wang, Zhiqiang Li, Nguyen Ly, Feimeng Zhou
Surface plasmon resonance (SPR) has been well established as a method of choice for label-free kinetic measurements of biomolecular interactions. The conventional approach involves multiple injections of an analyte of different concentrations into a fluidic channel covered with a fixed ligand density. Optimization of the experimental conditions and assessment of the data quality can be complicated by issues such as disruption of the ligand structure by the regeneration step and limited availability of the sample solution...
February 22, 2017: Analytical Chemistry
Angelo Bozzola, Sara Perotto, Francesco De Angelis
In this review we present the state of the art and the most recent advances in the field of optical sensing with hybrid plasmonic-photonic whispering gallery mode (WGM) resonators. After a brief introduction on the basic physics behind photonic WGM resonators and localized surface plasmon (LSP) nanostructures, we analyze the different types of optical sensors specifically designed for bulk refractive index sensing, molecular binding and single object detection. We point out the physical and technological key points of the different approaches proposed in the literature, and we systematically compare hybrid sensors and purely photonic WGM sensors...
February 22, 2017: Analyst
Joel D Cox, Andrea Marini, F Javier García de Abajo
High-harmonic generation in condensed-matter systems is both a source of fundamental insight into quantum electron motion and a promising candidate to realize compact ultraviolet and ultrafast light sources. While graphene is anticipated to efficiently generate high-order harmonics due to its anharmonic charge-carrier dispersion, experiments performed on extended samples using THz illumination have revealed only a weak effect. The situation is further complicated by the enormous electromagnetic field intensities required by this highly nonperturbative nonlinear optical phenomenon...
February 22, 2017: Nature Communications
Gangtao Dai, Zhiqiang Zhong, Xiaofeng Wu, Shiping Zhan, Shigang Hu, Pan Hu, Junshan Hu, Shaobing Wu, Junbo Han, Yunxin Liu
Lanthanide doped upconversion nanoparticles NaGdF4:Yb3+/Er3+ received increasing attention due to their unique optical-magnetic bifunctional properties. Here, we show that the luminescent intensity from NaGdF4:Yb3+/Er3+ nanoparticles decreases monotonously with increasing the applied magnetic field from 0 to 37.1 T, while Plasmon enhanced upconversion luminescence in Au/NaGdF4:Yb3+/Er3+ nanocomposite is independent from a magnetic field lower than 6 T. The surface plasmon resonances could compensate for the energetic mismatching between the excitation light and the energy level gaps induced by magnetic field and enhance the radiative efficiency that are main factors for achieving this stable upconversion emission in this nanocomposite under a magnetic field not higher than 6 T...
February 22, 2017: Nanotechnology
Vishal Kamat, Ashique Rafique
Rapid growth in the field of biotherapeutics has led to an increased demand for high-throughput, label-free biosensors exhibiting high sensitivity. To support the current needs, Sierra Sensors introduced a surface plasmon resonance imaging (SPRi) based biosensor, Molecular Affinity Screening System (MASS-1). We assessed the potential utility of MASS-1 to support Regeneron's therapeutic antibody discovery. A large panel of antibody-antigen interactions was characterized using MASS-1 and the kinetic data were compared with the Biacore 4000 biosensor...
February 18, 2017: Analytical Biochemistry
Alexander Köwitsch, Ankur Chhalotre, Thomas Groth
PURPOSE: The influence of extracellular matrix components like glycosaminoglycans (GAG) or adhesive proteins on the migration of cancer cells and the progression of tumorigenesis remains a challenging task. Therefore, this study aims to give insight into the interaction of cancer cells exhibiting different metastatic potential (MDA-MB-231, MDA-MB-468) with surface immobilized GAG interacting with serum proteins like fibronectin. METHODS: Model substrata were covalently coated with different thiolated GAG (hyaluronan (HA), chondroitin sulfate (CS), heparin (Hep)) and investigated for the adsorption of fibronectin (FN) with surface plasmon resonance...
February 18, 2017: International Journal of Artificial Organs
Ali Hatef, Naser Zamani, William Johnston
We systematically investigate the optical response of a semiconductor quantum dot (QD) hybridized with a vanadium dioxide nanoparticle (VO2NP) in the infrared (IR) region. The VO2NP features a semiconductor to metal phase change characteristic below and above a critical temperature that leads to an abrupt change in the particle's optical properties. This feature means that the QD-VO2NP hybrid system can support the coherent coupling of exciton-polaritons and exciton-plasmon polaritons in the semiconductor and metal phases of the VO2NP, respectively...
February 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Yefei Yin, Ze Wang, Shuguang Wang, Yujie Bai, Zuimin Jiang, Zhenyang Zhong
The photoluminescence from the Si and the SiGe is comprehensively modified by the Au NPs under the excitation without the surface plasmon resonance. Moreover, it sensitively depends on the size of the Au NPs, the excitation power and the thickness of Si between the Au NPs and the SiGe. A model is proposed in terms of the electrostatic effects of the naturally charged Au NPs due to the electron transferring through the nanoscale metal/semiconductor Schottky junction without an external bias and an external injection of carriers...
February 21, 2017: Nanotechnology
Si-Jing Ding, Da-Jie Yang, Jin-Ling Li, Gui-Ming Pan, Liang Ma, Yong-Jie Lin, Jia-Hong Wang, Li Zhou, Min Feng, Hongxing Xu, Shiwu Gao, Qu-Quan Wang
The surface plasmon resonance (SPR) of metal nanoparticles exhibits quantum behaviors as the size decreases owing to the transitions of quantized conduction electrons, but most studies are limited to the monotonous SPR blue-shift caused by off-resonant transitions. Here, we demonstrate the nonmonotonous SPR red-shift caused by resonant electron transitions and photocatalytic activity enhanced by the quantum plasmon resonance of colloidal gold nanoparticles. A maximal SPR wavelength and the largest photocatalytic activity are observed in the quantum regime for the first time for the gold nanoparticles with a diameter of 3...
February 21, 2017: Nanoscale
André Reinhard, Thorsten Nürnberger
Dissecting the functional basis of pathogenicity and resistance in the context of plant innate immunity benefits greatly from detailed knowledge about biomolecular interactions, as both resistance and virulence depend on specific interactions between pathogen and host biomolecules. While in vivo systems provide biological context to host-pathogen interactions, these experiments typically cannot provide quantitative biochemical characterization of biomolecular interactions. However, in many cases, the biological function does not only depend on whether an interaction occurs at all, but rather on the "intensity" of the interaction, as quantified by affinity...
2017: Methods in Molecular Biology
Jian Wei You, Jie You, Martin Weismann, Nicolae C Panoiu
Intriguing and unusual physical properties of graphene offer remarkable potential for advanced, photonics-related technological applications, particularly in the area of nonlinear optics at the deep-subwavelength scale. In this study, we use a recently developed numerical method to illustrate an efficient mechanism that can lead to orders of magnitude enhancement of the third-harmonic generation in graphene diffraction gratings. In particular, we demonstrate that by taking advantage of the geometry dependence of the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and discs one can engineer the spectral response of graphene gratings so that strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH)...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
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