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Surface plasmon resonance

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https://www.readbyqxmd.com/read/28544921/in-situ-formed-copper-nanoparticles-templated-by-tdt-mediated-dna-for-enhanced-spr-sensor-based-dna-assay
#1
Pei-Xin Yuan, Sheng-Yuan Deng, Chen-Yu Zheng, Serge Cosnier, Dan Shan
For the efficient surface plasmon resonance (SPR)-based DNA assay researching, signal amplification tactics were absolutely necessary. In this work, a sensitive SPR-DNA sensor was developed by employing in situ synthesis of copper nanoparticles (CuNPs) templated by poly-T sequences DNA from terminal deoxynucleotidyl transferase (TdT)-mediated extension, and synergistically with nano-effect deposition as the mass relay. The objective of this strategy was manifold: firstly, tDNA hybridized with the optimal designed probes to active the TdT-mediated DNA extension onto the surface of SPR chip, resulted a long poly-T sequences ssDNA chain in dsDNA terminal onto surface of gold chip and characterized by SPR signal amplitudes...
May 18, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28541828/simple-green-production-of-silver-nanoparticles-facilitated-by-bacterial-genomic-dna-and-their-antibacterial-activity
#2
Jiraporn Chumpol, Sineenat Siri
Green synthesis of AgNPs has gained many research interests as a low cost and eco-friendly approach. This work reported on the use of bacterial genomic DNA as the alternative biopolymer for a green production of AgNPs under a neutral pH. Although both ssDNA and dsDNA could function as stabilizing agents during the synthesis process, the ssDNA, generated by pre-heating the dsDNA at 100 °C, was more efficient to produce AgNPs with higher yield as determined by the intensity of the surface plasmon resonance (SPR) peak of silver at 475 nm...
May 25, 2017: Artificial Cells, Nanomedicine, and Biotechnology
https://www.readbyqxmd.com/read/28541708/highly-stable-monocrystalline-silver-clusters-for-plasmonic-applications
#3
Sergey M Novikov, Vladimir N Popok, Andrey B Evlyukhin, Muhammad Hanif, Per Morgen, Jacek Fiutowski, Jonas Beermann, Horst-Guenter Rubahn, Sergey I Bozhevolnyi
: Plasmonics sensor configurations utilizing localized plasmon resonances in silver nanostructures typically suffer from rapid degradation of silver in ambient atmospheric conditions. In this work, we report on the fabrication and detailed characterization of ensembles of monocrystalline silver nanoparticles (NPs), which exhibit a long-term stability of optical properties under ambient conditions without any protective treatments. Ensembles with different densities (surface coverages) of size-selected NPs (diameters from 12...
May 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28541355/strong-chiroptical-activity-from-achiral-gold-nanorods-assembled-with-proteins
#4
Hideyuki Shinmori, Chihiro Mochizuki
The side-by-side assembly of gold nanorods and proteins, particularly human serum albumin, exhibits a distinct chiroptical activity in a wide range of visible and near-infrared wavelengths corresponding to the surface plasmon resonance. The anisotropy factor was the highest in a colloidal solution system and was able to be inverted by an external environment.
May 25, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28541250/plasmonic-surface-nanostructuring-of-au-dots-sio2-via-laser-irradiation-induced-dewetting
#5
Ruixuan Yu, Tamaki Shibayama, Junya Ishioka, Xuan Meng, Yanhua Lei, Seiichi Watanabe
The in-situ observation of Au dot formation and the self-assembly dynamics of Au nanoparticles (NPs) was successfully demonstrated via dewetting of Au thin films on SiO<sub>2</sub> glass substrates under nano-second pulsed laser irradiation using a multi-quantum beam high-voltage electron microscope. Moreover, using electron energy-loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM), the plasmonic properties of the formed Au/SiO<sub>2</sub> nanostructure were analyzed to demonstrate its validity in advanced optical devices...
May 25, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28537028/enhanced-larvicidal-antibacterial-and-photocatalytic-efficacy-of-tio2-nanohybrids-green-synthesized-using-the-aqueous-leaf-extract-of-parthenium-hysterophorus
#6
Keerthika Thandapani, Manikandan Kathiravan, Elangovan Namasivayam, Indira Arulselvi Padiksan, Geetha Natesan, Manish Tiwari, Benelli Giovanni, Venkatachalam Perumal
Titanium dioxide nanoparticles are emerging as a biocompatible nanomaterial with multipurpose bioactivities. In this study, titanium dioxide (TiO2) nanoparticles were effectively synthesized using the aqueous leaf extracts of Parthenium hysterophorus prepared by microwave irradiation. TiO2 nanoparticles were fabricated by treating the P. hysterophorus leaf extracts with the TiO4 solution. Biologically active compounds such as alcohols, phenols, alkanes, and fluoroalkanes were involved in bioreduction of TiO4 into TiO2...
May 23, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28536157/identification-of-a-conformational-heparin-recognition-motif-on-the-peptide-hormone-secretin-key-role-for-cell-surface-binding
#7
Noe Quittot, Phuong Trang Nguyen, Armelle Tchoumi Nerée, Marc P Lussier, Steve Bourgault
Secretin is a peptide hormone that exerts pleiotropic physiological functions by specifically binding to its cognate membrane-bound receptor. The membrane catalysis model of peptide-receptor interactions states that soluble peptidic ligands initially interact with the plasma membrane. This interaction increases the local concentration and structures the peptide, enhancing the rate of receptor binding. However, this model does not consider the dense network of glycosaminoglycans (GAGs) at the surface of eukaryotic cells...
May 23, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28536098/rosuvastatin-and-atorvastatin-are-ligands-of-the-human-car-rxr%C3%AE-complex
#8
Tadeja Rezen, Mateja Hafner, Sandhya Kortagere, Sean Ekins, Vesna Hodnik, Damjana Rozman
Statins are well known lipid lowering agents that inhibit the enzyme HMG-CoA reductase. They also activate drug metabolism but their exact receptor-mediated action has not been proven so far. The aim of this study was to test if atorvastatin and rosuvastatin are direct ligands of human CAR. We measured binding activities of atorvastatin and rosuvastatin to the human CAR/RXRα-LBD heterodimer with surface plasmon resonance (SPR). Additionally, three-dimensional models of CAR/RXRα-LBD were constructed by ligand-based and structure-based in silico modelling...
May 23, 2017: Drug Metabolism and Disposition: the Biological Fate of Chemicals
https://www.readbyqxmd.com/read/28535885/development-of-a-simplified-approach-for-the-fabrication-of-localised-surface-plasmon-resonance-sensors-based-on-gold-nanorods-functionalized-using-mixed-polyethylene-glycol-layers
#9
Jing-Hong Pai, Chih-Tsung Yang, Hung-Yao Hsu, A Bruce Wedding, Benjamin Thierry
A simplified approach for the fabrication of localised surface plasmon resonance (LSPR) sensors based on gold nanorods (GNRs) is described and validated in a model immunoassay for the activated leukocyte cell adhesion molecule (ALCAM) cancer biomarker. Towards improving on standard bottom-up LSPR sensor fabrication methodologies, we demonstrate that GNRs bioconjugated with monoclonal antibodies can be readily covalently immobilized onto silanized glass substrates to yield highly sensitive LSPR sensors. To maximise the performance of the proposed sensors, mixed polyethylene glycol adlayers were optimized in regards to the bioconjugation of monoclonal antibodies using the standard carbodiimide chemistry...
June 29, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28535337/overall-structural-model-of-ns5a-protein-from-hepatitis-c-virus-and-modulation-by-mutations-confering-resistance-of-virus-replication-to-cyclosporin-a
#10
Aurelie Badillo, Veronique Brechot, Stephane Sarrazin, François-Xavier Cantrelle, Frederic Delolme, Marie-Laure Fogeron, Jennifer Molle, Roland Montserret, Anja Bockmann, Ralf Bartenschlager, Volker Lohmann, Guy Lippens, Sylvie Ricard-Blum, Xavier Hanoulle, Francois Penin
Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is a RNA-binding phosphoprotein composed of a N-terminal membrane anchor (AH), a structured domain 1 (D1) and two intrinsically disordered domains (D2 and D3). The knowledge of the functional architecture of this multifunctional protein remains limited. We report here that NS5A-D1D2D3 produced in a wheat germ cell-free system is obtained under a highly phosphorylated state. Its NMR analysis revealed that these phosphorylations do not change the disordered nature of D2 and D3 domains but increase the number of conformers due to partial phosphorylations...
May 23, 2017: Biochemistry
https://www.readbyqxmd.com/read/28534621/spectral-response-of-plasmonic-gold-nanoparticles-to-capacitive-charging-morphology-effects
#11
Benjamin S Hoener, Hui Zhang, Thomas S Heiderscheit, Silke R Kirchner, Agampodi Swarnapali De Silva Indrasekara, Rashad Baiyasi, Yi-Yu Cai, Peter Nordlander, Stephan Link, Christy F Landes, Wei-Shun Chang
We report a study of the shape-dependent spectral response of the gold nanoparticle surface plasmon resonance at various electron densities to provide mechanistic insight into the role of capacitive charging, a topic of some debate. We demonstrate a morphology dependent spectral response for gold nanoparticles due to capacitive charging using single-particle spectroscopy in an inert electrochemical environment. A decrease in plasmon energy and increase in spectral width for gold nanospheres and nanorods was observed as the electron density was tuned through a potential window of -0...
May 23, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28533486/galectin-3-acts-as-an-angiogenic-switch-to-induce-tumor-angiogenesis-via-jagged-1-notch-activation
#12
Sofia Nascimento Dos Santos, Helen Sheldon, Jonathas Xavier Pereira, Christopher Paluch, Esther M Bridges, Márcia Curry El-Cheikh, Adrian L Harris, Emerson Soares Bernardes
Angiogenesis is a coordinated process tightly regulated by the balance between Delta-like-4 (DLL4) and Jagged-1 (JAG1) in endothelial cells. Here we show that galectin-3 (gal-3), a glycan-binding protein secreted by cancer cells under hypoxic conditions, triggers sprouting angiogenesis, assisted by hypoxic changes in the glycosylation status of endothelial cells that enhance binding to gal-3. Galectin-3's proangiogenic functions were found to be predominantly dependent on the Notch ligand JAG1. Differential direct binding to JAG1 was shown by surface plasmon resonance assay...
May 9, 2017: Oncotarget
https://www.readbyqxmd.com/read/28533135/enhanced-local-disorder-in-a-clinically-elusive-von-willebrand-factor-provokes-high-affinity-platelet-clumping
#13
Alexander Tischer, Venkata R Machha, Juan P Frontroth, Maria A Brehm, Tobias Obser, Reinhard Schneppenheim, Leland Mayne, S Walter Englander, Matthew Auton
Mutation of the cysteines forming the disulfide loop of the platelet GPIbα adhesive A1 domain of von Willebrand factor causes quantitative VWF deficiencies in the blood and von Willebrand disease. We report two cases of transient severe thrombocytopenia induced by DDAVP-treatment. Cys1272Trp and Cys1458Tyr mutations identified by genetic sequencing implicate an abnormal gain-of-function phenotype, evidenced by thrombocytopenia, that quickly relapses back to normal platelet counts and deficient plasma VWF. Using surface plasmon resonance, analytical rheology, and hydrogen-deuterium exchange mass spectrometry (HXMS), we decipher mechanisms of A1-GPIbα mediated platelet adhesion and resolve dynamic secondary structure elements that regulate the binding pathway...
May 19, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28532130/effect-of-systematic-control-of-pd-thickness-and-annealing-temperature-on-the-fabrication-and-evolution-of-palladium-nanostructures-on-si-111-via-the-solid-state-dewetting
#14
Sundar Kunwar, Puran Pandey, Mao Sui, Quanzhen Zhang, Ming-Yu Li, Jihoon Lee
Si-based optoelectronic devices embedded with metallic nanoparticles (NPs) have demonstrated the NP shape, size, spacing, and crystallinity dependent on light absorption and emission induced by the localized surface plasmon resonance. In this work, we demonstrate various sizes and configurations of palladium (Pd) nanostructures on Si (111) by the systematic thermal annealing with the variation of Pd thickness and annealing temperature. The evolution of Pd nanostructures are systematically controlled by the dewetting of thin film by means of the surface diffusion in conjunction with the surface and interface energy minimization and Volmer-Weber growth model...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28531089/au-nanoparticle-decorated-silicon-pyramids-for-plasmon-enhanced-hot-electron-near-infrared-photodetection
#15
Zhiyang Qi, Yusheng Zhai, Long Wen, Qilong Wang, Qin Chen, Sami Iqbal, Guangdian Chen, Ji Xu, Yan Tu
Heterojunction between metal and silicon (Si) is an attractive route to extend the response of Si-based photodiodes into the near-infrared (NIR) region, so-called Schottky barrier diodes. Photons absorbed into a metallic nanostructure excite the surface plasmon resonances (SPRs), which can be damped non-radiatively through the creation of hot electrons. Unfortunately, quantum efficiency of hot electron detectors remains low due to low optical absorption and poor electron injection efficiency. In this study, we propose an efficient and low-cost plasmonic hot electron NIR photodetector based on Au nanoparticle (Au NP)-decorated Si pyramid Schottky junction...
May 22, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28530599/a-saliva-molecular-imprinted-localized-surface-plasmon-resonance-biosensor-for-wine-astringency-estimation
#16
J Rafaela L Guerreiro, Natércia Teixeira, Victor De Freitas, M Goreti F Sales, Duncan S Sutherland
Wine astringency was evaluated based on the interaction of two complex matrices (red wine and saliva) by combining localized surface plasmon resonance (LSPR) and molecular imprinted polymers (MIP) at gold nanodisks as an alternative to sensorial analysis. The main objective of the work was to simulate wine astringency inside the mouth by mimicking this biological system. The LSPR/MIP sensor provided a linear response for astringency expressed in pentagalloyl glucose (PGG) units in concentrations ranging from 1 to 140μmol/L...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28530195/facile-synthesis-of-silver-nanoparticles-mediated-by-polyacrylamide-reduction-approach-to-antibacterial-application
#17
Hosam I Salaheldin, Meshal H K Almalki, Abd Elhameed M Hezma, Gamal E H Osman
The current time increase in the prevalence of antibiotic resistant 'super-bugs' and the risks associated with food safety have become global issues. Therefore, further research is warranted to identify new and effective antimicrobial substances. Silver nanoparticles (Ag-NPs) were synthesized by autoclaving technique using, different concentrations of Ag salt (AgNO3) solution (1, 5, 10, and 25 mM). Their presence was confirmed by a surface plasmon resonance band at ∼435 nm using UV-Vis absorption spectra...
June 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28530191/green-synthesis-of-silver-nanoparticles-using-bovine-skin-gelatin-and-its-antibacterial-effect-on-clinical-bacterial-isolates
#18
Hosam I Salaheldin, Meshal H K Almalki, Gamal E H Osman
Nanoparticles are being increasingly used in day-to-day life. Therefore, concerns have been raised regarding their interactions with the surrounding environment. This study focused on a simple green method for synthesizing silver nanoparticles (Ag-NPs) in an autoclave at 15 psi (103 kPa) and 121°C. An aqueous solution of AgNO3 as a precursor of Ag-NPs and gelatin (type B) reducing and/or stabilizing (capping) agent were used. The effect of various AgNO3 concentrations of certain gelatin concentration and various gelatin concentrations at constant AgNO3 concentration, and autoclaving time, was studied...
June 2017: IET Nanobiotechnology
https://www.readbyqxmd.com/read/28528543/plasmon-enhanced-energy-transfer-in-photosensitive-nanocrystal-device
#19
Shahab Akhavan, Mehmet Zafer Akgul, Pedro Ludwig Hernandez Martinez, Hilmi Volkan Demir
Förster resonance energy transfer (FRET) interacted with localized surface plasmon (LSP) gives us the ability to overcome inadequate transfer of energy between donor and acceptor nanocrystals (NCs). In this paper, we show LSP-enhanced FRET in colloidal photosensors of NCs in operation, resulting in substantially enhanced photosensitivity. The proposed photosensitive device is a layered self-assembled colloidal platform consisting of separated monolayers of the donor and the acceptor colloidal NCs with an intermediate metal nanoparticle (MNP) layer made of gold inter-spaced by polyelectrolyte layers...
May 20, 2017: ACS Nano
https://www.readbyqxmd.com/read/28527412/early-stage-detection-of-ve-cadherin-during-endothelial-differentiation-of-human-mesenchymal-stem-cells-using-spr-biosensor
#20
Farzaneh Fathi, Aysa Rezabakhsh, Reza Rahbarghazi, Mohammad-Reza Rashidi
Surface plasmon resonance (SPR) biosensors are most commonly applied for real-time dynamic analysis and measurement of interactions in bio-molecular studies and cell-surface analysis without the need for labeling processes. Up to present, SPR application in stem cell biology and biomedical sciences was underused. Herein, a very simple and sensitive method was developed to evaluate human mesenchymal stem cells trans-differentiation to endothelial lineage of over a period of 14 days based on VE-cadherin biomarker...
May 10, 2017: Biosensors & Bioelectronics
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