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Surface plasmon resonance

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https://www.readbyqxmd.com/read/28749589/precisely-assembled-cyclic-gold-nanoparticle-frames-via-2d-polymer-single-crystal-templating
#1
Christopher Yuren Li, Shan Mei, Hao Qi, Tian Zhou
In recent decades, extensive studies have been devoted to assembling nanoparticles (NPs) into various ordered structures to achieve novel optical properties. It however still remains a challenging task to assemble NPs into cyclic one-dimensional (1D) shapes such as rings and frames. In this work, we report a directed assembly method to precisely assemble NPs into well-defined, free-standing frames using polymer single crystals (PSCs) as the template. Preformed poly(ethylene oxide) (PEO) single crystals were used as the template to direct the crystallization of block copolymer (BCP) poly(ethylene oxide)-b-poly(4-vinylpyridine) (PEO-b-P4VP), which directed gold NPs (AuNPs) to form AuNP frames...
July 27, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28747434/thrombospondin-1-tsp-1-a-new-bone-morphogenetic-protein-2-and-4-bmp-2-4-antagonist-identified-in-pituitary-cells
#2
Céline Sallon, Isabelle Callebaut, Ida Boulay, Joel Fontaine, Delphine Logeart-Avramoglou, Corinne Henriquet, Martine Pugnière, Xavier Cayla, Philippe Monget, Grégoire Harichaux, Valérie Labas, Sylvie Canepa, Catherine Taragnat
Bone morphogenetic proteins (BMPs) regulate diverse cellular responses during embryogenesis and in adulthood including cell differentiation, proliferation and death in various tissues. In the adult pituitary, BMPs participate in the control of hormone secretion and cell proliferation suggesting a potential endocrine/paracrine role for BMPs, but some of the mechanisms are unclear. Here, using a bioactivity test based on embryonic cells (C3H10T1/2) transfected with a BMP-responsive element, we sought to determine whether pituitary cells secrete BMPs or BMP antagonists...
July 26, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28746830/biophysical-characterization-of-e-coli-tolc-interaction-with-the-known-blocker-hexaamminecobalt
#3
A Gilardi, S P Bhamidimarri, M Brönstrup, U Bilitewski, R K R Marreddy, K M Pos, L Benier, P Gribbon, M Winterhalter, B Windshügel
BACKGROUND: The tripartite efflux pump AcrAB-TolC in E. coli is involved in drug resistance by transporting antibiotics out of the cell. The outer membrane protein TolC can be blocked by various cations, including hexaamminecobalt, thereby TolC represents a potential target for reducing antimicrobial resistance as its blockage may improve efficacy of antibiotics. METHODS: We utilized single channel electrophysiology measurements for studying TolC conductance in absence and presence of the known TolC blocker hexaamminecobalt...
July 23, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28746731/towards-improved-oligonucleotide-therapeutics-through-faster-target-binding-kinetics
#4
Mirjam Menzi, Bettina Wild, Ugo Pradère, Andreas Brunschweiger, Anna L Malinowska, Helen Louise Lightfoot, Jonathan Hall
When used as inhibitors of gene expression in vivo, oligonucleotides require modification of their structures to boost their binding affinity for complementary target RNAs. To date, hundreds of modifications have been designed and tested but few have proven to be useful. Among those investigated are mono- and polyamino-groups. These are positively charged at physiological pH and have been appended to oligonucleotides in an effort to reduce electrostatic repulsion during hybridization to RNAs, but have generally shown relatively minor benefits to binding...
July 26, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28745060/tunable-fluorescence-of-a-semiconducting-polythiophene-positioned-on-dna-origami
#5
Johanna Zessin, Franziska Fischer, Andreas Heerwig, Alfred Kick, Susanne Boye, Manfred Stamm, Anton Kiriy, Michael Mertig
A novel approach for the integration of π-conjugated polymers (CPs) into DNA-based nanostructures is presented. Using the controlled Kumada catalyst-transfer polycondensation, well-defined thiophene-based polymers with controllable molecular weight, specific end groups and water-soluble oligoethylene glycol-based side chains were synthesized. The end groups were used for the easy but highly efficient click chemistry-based attachment of end-functionalized oligodeoxynucleotides (ODNs) with predesigned sequences...
July 26, 2017: Nano Letters
https://www.readbyqxmd.com/read/28743841/double-fano-resonances-in-individual-metallic-nanostructure-for-high-sensing-sensitivity
#6
Zhendong Yan, Xiangmin Wen, Ping Gu, Zhong Huang, Peng Zhan, Zhuo Chen, Zhenlin Wang
In this paper, we report the design and observation of double Fano resonances (DFRs) in an individual symmetry reduced nanostructure and the induced high sensing sensitivity. Such a plasmonic nanostructure consists of a partially overlapped double metallic nanotriangles with unequal sizes fabricated by using the fast and low-cost angle-resolved nanosphere lithography. Symmetry breaking generates two narrow quadrupolar dark modes, which further enhance the coupling with fundamental bright dipole modes within the same structure, manifesting the effect of DFRs...
July 26, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28743169/development-and-validation-of-an-optical-biosensor-for-rapid-monitoring-of-adalimumab-in-serum-of-patients-with-crohn-s-disease
#7
Sumin Bian, Jiadi Lu, Filip Delport, Séverine Vermeire, Dragana Spasic, Jeroen Lammertyn, Ann Gils
Therapeutic drug monitoring of adalimumab is recommended to improve therapeutic outcome in patients with Crohn's disease. Performing an ELISA requires a rather long time-to-result and the necessity of collecting multiple samples in order to decrease the cost per adalimumab determination. In this study, we aim to develop and validate a rapid assay suitable for measuring a single adalimumab serum sample using a fiber-optic surface plasmon resonance (FO-SPR) based sensor. Therefore, we have immobilized MA-ADM28B8 as capture antibody on a FO-probe and conjugated MA-ADM40D8 as detecting antibody to gold nanoparticles...
July 25, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28743089/understanding-the-interaction-of-concanavalin-a-with-mannosyl-glycoliposomes-a-surface-plasmon-resonance-and-fluorescence-study
#8
Catalina Sandoval-Altamirano, Susana A Sanchez, Nancy F Ferreyra, German Gunther
The specificity of carbohydrate-protein interaction is a key factor in many biological processes and it is the foundation of technologies using glycoliposomes in drug delivery. The incorporation of glycolipids in vesicles is expected to increase their specificity toward particular targets such as lectins; however, the degree of exposure of the carbohydrate moiety at the liposome surface is a crucial parameter to be considered in the interaction. Herein we report the synthesis of mannose derivatives with one or two hydrophobic chains of different length, designed with the purpose of modifying the degree of exposure of the mannose when they were incorporated into liposomes...
July 18, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28743029/thermoresponsive-nanoparticle-agglomeration-aggregation-in-salt-solutions-dependence-on-graft-density
#9
Thaddeus W Vasicek, Samir V Jenkins, Leticia Vaz, Jingyi Chen, Julie A Stenken
Gold nanoparticles with a graft density of 0.09, 0.30 and 0.40chains/nm(2) of poly(N-isopropylacrylamide) were reproducibly synthesized by varying the ratio of disulfide terminated poly(N-isopropylacrylamide) to gold nanoparticle. The polymer coated nanoparticles were stable at room temperature in 50mM NaCl, yet agglomerated at 37°C. Previous studies have observed conflicting results as to the reversibility of this agglomeration. Particle agglomeration with three different graft densities was studied in 50mM NaCl by measurements of their localized surface plasmon resonance and hydrodynamic diameter, and imaging with electron microscopy...
July 17, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28741643/self-reference-plasmonic-sensors-based-on-double-fano-resonances
#10
Yujia Wang, Chengwei Sun, Hongyun Li, Qihuang Gong, Jianjun Chen
High-sensitivity plasmonic refractive index sensors show great applications in the areas of biomedical diagnostics, healthcare, food safety, environmental monitoring, homeland security, and chemical reactions. However, the unstable and complicated environments considerably limit their practical applications. By employing the independent double Fano resonances in a simple metallic grating, we experimentally demonstrate a self-reference plasmonic sensor, which significantly reduces the error contributions of the light intensity fluctuations in the long-distance propagation and local temperature variations at the metallic grating, and the detection accuracy is guaranteed...
July 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28741598/plasmonic-enhancement-of-cyanine-dyes-for-near-infrared-light-triggered-photodynamic-photothermal-therapy-and-fluorescent-imaging
#11
Mindan Lu, Ning Kang, Chuan Chen, Liuqing Yang, Yang Li, Minghui Hong, Xiangang Luo, Lei Ren, Xiumin Wang
Near infrared (NIR) triggered cyanine dyes have attracted considerable attentions in multi-modal tumor theranostics. However, near infrared (NIR) cyanine dyes used in tumor treatment often suffer from low fluorescence intensity and weak singlet oxygen generation efficiency, resulting in inadequate diagnostic and therapy efficacies for tumors. It is still a great challenge to improve both the photodynamic therapy (PDT) and fluorescent imaging (FLI) efficacy of cyanine dyes in tumor applications. Herein, a novel multifunctional nanoagent of AuNRs@SiO2-IR795 was developed to realize the integrated photothermal/photodynamic therapy (PTT/PDT) and FLI at a very low dosage of IR795 (0...
July 25, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28738618/high-sensitivity-surface-plasmon-resonance-biosensor-for-detection-of-microrna-and-small-molecule-based-on-graphene-oxide-gold-nanoparticles-composites
#12
Qing Li, Qing Wang, Xiaohai Yang, Kemin Wang, Hua Zhang, Wenyan Nie
A versatile and sensitive surface plasmon resonance (SPR) biosensor based on two layers of graphene oxide-gold nanoparticles (GO-AuNPs) composites was designed for the detection of microRNA (miRNA) and small molecule adenosine. The bottom layer, which acted as a functionalized substrate on the sensor chip, provided a high specific surface area convenient for the immobilization of capture DNA molecules. The upper layer served as a signal-amplification element. By employing these two layers of GO-AuNPs composites, the dual amplification strategy was achieved so that a measurement of miRNA-141 with a detection limit of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28737382/solid-state-plasmonic-solar-cells
#13
Kosei Ueno, Tomoya Oshikiri, Quan Sun, Xu Shi, Hiroaki Misawa
Metallic nanoparticles such as silver and gold show localized surface plasmon resonances (LSPRs), which are associated with near-field enhancement effects in the vicinity of nanoparticles. Therefore, strong light-matter interaction is induced by the near-field enhancement effects of LSPRs. Because the resonant wavelength of LSPRs can be easily controlled by the size and shape of the metallic nanoparticles in the visible and near-infrared wavelength range, LSPRs have received considerable attention as optical antennae for light energy conversion systems such as solar cells...
July 24, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28734932/a-pyridone-derivative-activates-serca2a-by-attenuating-the-inhibitory-effect-of-phospholamban
#14
Manami Kaneko, Hisato Yamamoto, Hiroki Sakai, Yusuke Kamada, Toshiki Tanaka, Shuji Fujiwara, Synsuke Yamamoto, Hiroki Takahagi, Hideyuki Igawa, Shizuo Kasai, Masakuni Noda, Makoto Inui, Tomoyuki Nishimoto
The cardiac sarco/endoplasmic reticulum Ca(2+)-dependent ATPase 2a (SERCA2a) plays a central role in Ca(2+) handling within cardiomyocytes and is negatively regulated by phospholamban (PLN), a sarcoplasmic reticulum (SR) membrane protein. The activation of SERCA2a, which has been reported to improve cardiac dysfunction in heart failure, is a potential therapeutic approach for heart failure. Therefore, we developed a novel small molecule, compound A and characterized it both in vitro and in vivo. Compound A activated the Ca(2+)-dependent ATPase activity of cardiac SR vesicles but not that of skeletal muscle SR vesicles that lack PLN...
July 19, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28732866/probing-cleavage-promiscuity-of-heparinase-iii-towards-chemoenzymatically-synthetic-heparan-sulfate-oligosaccharides
#15
Guixin Hu, Meng Shao, Xin Gao, Fengshan Wang, Chunhui Liu
An insightful investigation into specificity of bacterial heparinase III has been intriguingly difficult due to heterogeneity of polymeric substrates. Herein, we chemoenzymatically synthesized a tailored library of HS oligosaccharides as substrates. A ∼15-fold reactivity difference to heparinase III was found between trisaccharides bearing different primary cleavage sites. Variable glucosamine modification decreased reactivity of trisaccharides by >20-fold compared with their counterpart primary substrates, while iduronate-containing secondary linkage showed slightly less sensitivity...
October 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28732041/understanding-russell-s-viper-venom-factor-v-activator-s-substrate-specificity-by-surface-plasmon-resonance-and-in-silico-studies
#16
Pradeep K Yadav, Christian B Antonyraj, Syed Ibrahim Basheer Ahamed, Sistla Srinivas
Blood coagulation factor V (FV) is activated either by Factor X or thrombin, cleaving at three different sites viz., Site I (Arg709-Ser710), site II (Arg1018-Thr1019), and site III (Arg1545-Ser1546). Russell's viper venom factor V activator (RVV-V) is a thrombin-like serine proteinase that activates FV with selective, single cleavage at site III. A long lasting effort is being pending in understanding the 'selective' binding specificity of the RVV-V towards site III. Here, we present the binding kinetic study of RVV-V with two designed peptides corresponding to the regions from site I (Gln699-Asn713) and site II (1008Lys-Pro1022), respectively, that include 15 amino acids...
2017: PloS One
https://www.readbyqxmd.com/read/28731574/rapid-buffer-and-ligand-screening-for-affinity-chromatography-by-multiplexed-surface-plasmon-resonance-imaging
#17
Karin P M Geuijen, Daniëlle E J W van Wijk-Basten, David F Egging, Richard B M Schasfoort, Michel H Eppink
Protein purifications are often based on the principle of affinity chromatography, where the protein of interest selectively binds to an immobilized ligand. The development of affinity purification requires selecting proper wash and elution conditions. In recent years, miniaturization of the purification process is applied to speed up the development (e.g. microtiterplates, robocolumns). We have studied the application of surface plasmon resonance imaging (SPRi) as a tool to simultaneously screen many buffer conditions for wash and elution steps in an affinity-based purification process...
July 21, 2017: Biotechnology Journal
https://www.readbyqxmd.com/read/28731438/evidence-that-the-human-innate-immune-peptide-ll-37-may-be-a-binding-partner-of%C3%A2-amyloid-%C3%AE-and-inhibitor-of%C3%A2-fibril-assembly
#18
Ersilia De Lorenzi, Marcella Chiari, Raffaella Colombo, Marina Cretich, Laura Sola, Renzo Vanna, Paola Gagni, Federica Bisceglia, Carlo Morasso, Jennifer S Lin, Moonhee Lee, Patrick L McGeer, Annelise E Barron
BACKGROUND: Identifying physiologically relevant binding partners of amyloid-β (Aβ) that modulate in vivo fibril formation may yield new insights into Alzheimer's disease (AD) etiology. Human cathelicidin peptide, LL-37, is an innate immune effector and modulator, ubiquitous in human tissues and expressed in myriad cell types. OBJECTIVE: We present in vitro experimental evidence and discuss findings supporting a novel hypothesis that LL-37 binds to Aβ42 and can modulate Aβ fibril formation...
July 18, 2017: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/28730812/potential-scanning-localized-plasmon-sensing-with-single-and-coupled-gold-nanorods
#19
Tokuhisa Kawawaki, Heyou Zhang, Hiroyasu Nishi, Paul Mulvaney, Tetsu Tatsuma
Single plasmonic nanoparticles can potentially serve as optical sensors for detecting local refractive index changes. However, simultaneous monitoring of the scattering spectra from multiple nanoparticles is not practical. Here we perform potential-scanning localized surface plasmon resonance (LSPR) sensing. Gold nanorods are immobilized on an ITO electrode. Instead of collecting the full spectrum, as is done in conventional LSPR sensing, the electrode potential is scanned while the rod spectra are monitored at a single wavelength...
July 21, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28730357/biosynthesis-of-silver-nanoparticles-from-spirulina-microalgae-and-its-antibacterial-activity
#20
Govarthanan Muthusamy, Selvankumar Thangasamy, Mythili Raja, Sudhakar Chinnappan, Selvam Kandasamy
The present work focuses on a low-cost, simple, and green synthesis of silver nanoparticles (AgNPs) by mixing AgNO3 solution with the extract of Spirulina platensis (SP) without any chemical reducing and/or capping agents. The green synthesis of AgNPs was confirmed by the color change from colorless to yellowish brown. The biosynthesis of AgNPs was further confirmed by UV-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), biological transmission electron microscopy (Bio-TEM), and energy dispersive X-ray analysis (EDX)...
July 20, 2017: Environmental Science and Pollution Research International
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