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Surface plasmons

Antonino Rapisarda, Nicoletta Giamblanco, Giovanni Marletta
Clinical application of DNA microarrays used for screening of single nucleotide polymorphisms (SNPs) are very important for diagnosis of diseases and appropriate treatment of patients. In this paper localized surface plasmon resonance (LSPR) technique has been used to study the DNA hybridization process for binary solutions of respectively perfectly matching (PM) and single base mismatching (MM) 93-mer ssDNA from KRAS codon 12. 5'-thiol modified 35-mer ssDNA has been linked to the Au nanodisks array as probe with a surface coverage of 2...
October 14, 2016: Journal of Colloid and Interface Science
Flavia A Mercurio, Daniela Marasco, Concetta Di Natale, Luciano Pirone, Susan Costantini, Emilia M Pedone, Marilisa Leone
The EphA2 receptor controls diverse physiological and pathological conditions and its levels are often upregulated in cancer. Targeting receptor overexpression, through modulation of endocytosis and consequent degradation, appears to be an appealing strategy for attacking tumor malignancy. In this scenario, the Sam domain of EphA2 plays a pivotal role because it is the site where protein regulators of endocytosis and stability are recruited by means of heterotypic Sam-Sam interactions. Because EphA2-Sam heterotypic complexes are largely based on electrostatic contacts, we have investigated the possibility of attacking these interactions with helical peptides enriched in charged residues...
October 20, 2016: Chembiochem: a European Journal of Chemical Biology
Qiangbing Guo, Meixi Ji, Yunhua Yao, Meng Liu, Zhi-Chao Luo, Shian Zhang, Xiaofeng Liu, Jianrong Qiu
Here, we show that solution-processed Cu-Sn-S semiconductor nanocrystals (NCs) demonstrate a tunable localized surface plasmon resonance band in the near infrared region, where strong saturable absorption occurs. A saturable absorber based on these plasmonic NCs enables the construction of a stable mode-locked femtosecond fiber laser operating at the telecommunication band.
October 20, 2016: Nanoscale
Jibin Song, Peng Huang, Xiaoyuan Chen
Gold nanovesicles contain multiple nanocrystals within a polymeric coating. The strong plasmonic coupling between adjacent nanoparticles in their vesicular shell makes ultrasensitive biosensing and bioimaging possible. In our laboratory, multifunctional plasmonic vesicles are assembled from amphiphilic gold nanocrystals (such as gold nanoparticles and gold nanorods) coated with mixed hydrophilic and hydrophobic polymer brushes or amphiphilic diblock co-polymer brushes. To fulfill the different requirements of biomedical applications, different polymers that are either pH=responsive, photoactive or biodegradable can be used to form the hydrophobic brush, while the hydrophilicity is maintained by polyethylene glycol (PEG)...
November 2016: Nature Protocols
Nicolas Marinval, Pierre Saboural, Oualid Haddad, Murielle Maire, Kevin Bassand, Frederic Geinguenaud, Nadia Djaker, Khadija Ben Akrout, Marc Lamy de la Chapelle, Romain Robert, Olivier Oudar, Erwan Guyot, Christelle Laguillier-Morizot, Angela Sutton, Cedric Chauvierre, Frederic Chaubet, Nathalie Charnaux, Hanna Hlawaty
Herein we investigate the structure/function relationships of fucoidans from Ascophyllum nodosum to analyze their pro-angiogenic effect and cellular uptake in native and glycosaminoglycan-free (GAG-free) human endothelial cells (HUVECs). Fucoidans are marine sulfated polysaccharides, which act as glycosaminoglycans mimetics. We hypothesized that the size and sulfation rate of fucoidans influence their ability to induce pro-angiogenic processes independently of GAGs. We collected two fractions of fucoidans, Low and Medium Molecular Weight Fucoidan (LMWF and MMWF, respectively) by size exclusion chromatography and characterized their composition (sulfate, fucose and uronic acid) by colorimetric measurement and Raman and FT-IR spectroscopy...
October 17, 2016: Marine Drugs
Yvonne Voß, Ekram Wassel, Siyu Jiang, Qimeng Song, Sergey I Druzhinin, Holger Schönherr
Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes, which are known to suppress protein adsorption and prevent cell attachment, are reported here to possess interesting and tunable thermoresponsive behavior, if the brush thickness is reduced or the grafting density is altered. PDEGMA brushes with a dry ellipsometric thickness of 5 ± 1 nm can be switched from cell adherent behavior at 37 °C to cell nonadherent at 25 °C. This behavior coincides with the temperature-dependent irreversible adsorption of fibronectin from phosphate saline buffer and proteins present in the cell culture medium, as unveiled by surface plasmon resonance measurements...
October 20, 2016: Macromolecular Bioscience
Guang Yang, Daniel T Hallinan
Using a three-phase system, centimeter-scale monolayer gold nanoparticle (Au NP) films have been prepared that have long-range order and hydrophobic ligands. The system contains an interface between an aqueous phase containing Au NPs and an oil phase containing one of various types of amine ligands, and a water/air interface. As the Au NPs diffuse to the water/oil interface, ligand exchange takes place which temporarily traps them at the water/oil interface. The ligand-exchanged particles then spontaneously migrate to the air/water interface, where they self-assemble, forming a monolayer under certain conditions...
October 20, 2016: Scientific Reports
Christopher J Day, Rebecca M King, Lucy K Shewell, Greg Tram, Tahria Najnin, Lauren E Hartley-Tassell, Jennifer C Wilson, Aaron D Fleetwood, Igor B Zhulin, Victoria Korolik
A rare chemotaxis receptor, Tlp11, has been previously identified in invasive strains of Campylobacter jejuni, the most prevalent cause of bacterial gastroenteritis worldwide. Here we use glycan and small-molecule arrays, as well as surface plasmon resonance, to show that Tlp11 specifically interacts with galactose. Tlp11 is required for the chemotactic response of C. jejuni to galactose, as shown using wild type, allelic inactivation and addition mutants. The inactivated mutant displays reduced virulence in vivo, in a model of chicken colonization...
October 20, 2016: Nature Communications
Sheng-Hung Wang, John Yu
To develop peptide-conjugated liposomes for cancer imaging and therapy, the label-free surface plasmon resonance (SPR) biosensor (Biacore™) is a practical and also preferred strategy to examine protein-peptide interaction. A new Biacore protocol with "oriented immobilization" for peptide-binding assay, which overcomes the drawbacks of conventional protocols, was presented in this data article. These results were complementary to the research article Wang at al., [1], which reported a series of new cancer-targeting peptides found with HotLig software (Wang et al...
June 2016: Data in Brief
Hiroshi Imamura, Shinya Honda
Calibration-free concentration analysis (CFCA) based on surface plasmon resonance uses the diffusion coefficient of an analyte to determine the concentration of that analyte in a bulk solution. In general, CFCA is avoided when investigating analytes prone to self-association, as the heterogeneous diffusion coefficient results in a loss of precision. The derivation for self-association of the analyte was presented here. By using the diffusion coefficient for the monomeric state, CFCA provides the lowest possible concentration even though the analyte is self-associated...
October 16, 2016: Analytical Biochemistry
Jing-Min Liu, Yao-Yao Liu, Dong-Dong Zhang, Guozhen Fang, Shuo Wang
The rise of multimodal nanoprobes has promoted the development of new methods to explore multiple molecular targets simultaneously, or to combine various bioimaging tools in one assay to more clearly delineate localization and expression of bio-markers. Persistent luminescence nanophosphors (PLNPs) have been qualified as the promising contrast agent for in vivo imaging. The easy surface modification and proper nanostructure design strategy would favor the fabrication of PLNPs based multi-functional nanoprobes for biological application...
October 19, 2016: ACS Applied Materials & Interfaces
Kan Zhang, Shansheng Yu, Baoming Jv, Weitao Zheng
In this work, the adsorption of Rhodamine 6G molecules on some graphene substrates is investigated using density functional theory. Some simple models, such as those of perfect graphene, defective graphene, *O/*OH modified graphene and B/N doping graphene, are constructed as substrates to simulate graphene oxide and B/N doping graphene sheets. It is demonstrated that the interactions of Rhodamine 6G molecules with graphene materials are strong. In particular, the amine group of Rhodamine 6G molecules can favor the formation of a chemical bond with some graphene substrates characterized by under-coordinated atoms...
October 19, 2016: Physical Chemistry Chemical Physics: PCCP
Catia Contado, Roberto Argazzi, Vincenzo Amendola
Many advanced industrial and biomedical applications that use silver nanoparticles (AgNPs), require that particles are not only nano-sized, but also well dispersed, not aggregated and not agglomerated. This study presents two methods able to give rapidly sizes of monodispersed AgNPs suspensions in the dimensional range of 20-100nm. The first method, based on the application of Mie's theory, determines the particle sizes from the values of the surface plasmon resonance wavelength (SPRMAX), read from the optical absorption spectra, recorded between 190nm and 800nm...
October 13, 2016: Journal of Chromatography. A
Benjamin T Diroll, Peijun Guo, Robert P H Chang, Richard D Schaller
Epsilon-near-zero materials may be synthesized as colloidal nanocrystals which display large magnitude sub-picosecond switching of infrared localized surface plasmon resonances. Such nanocrystals offer a solution-processable, scalable source of tunable metamaterials compatible with arbitrary substrates. Under intraband excitation, these nanocrystals display a red-shift of the plasmon feature arising from the low electron heat capacities and conduction band non-parabolicity of the oxide. Under interband pumping, they show in an ultrafast blueshift of the plasmon resonance due to transient increases in the carrier density...
October 18, 2016: ACS Nano
Langdong Chen, Diya Lv, Dongyao Wang, Xiaofei Chen, Zhenyu Zhu, Yan Cao, Yifeng Chai
Herbal medicines have long been widely used in the treatment of various complex diseases in China. However, the active constituents and therapeutic mechanisms of many herbal medicines remain undefined. Therefore, the identification of the active components and target proteins in these herbal medicines is a formidable task in herbal medicine research. In this study, we proposed a strategy, which integrates network pharmacology with biomedical analysis and surface plasmon resonance (SPR) to predict the active ingredients and potential targets of herbal medicine Sophora flavescens or Kushen in Chinese, and evaluate its anti-fibrosis activity...
October 18, 2016: Molecular BioSystems
Yuki Osaka, Satoshi Sugano, Shuichi Hashimoto
Fabricating nano-sized through-holes on a coverslip approximately 100 μm thick is challenging but rewarding when applied to ultrafine filters that separate proteins and DNA of various sizes and isolate viruses from cells. Toward this end, we developed an in situ etching-assisted laser processing technique exploiting gold nanoparticles. Plasmonic heating of a single gold nanoparticle through focused illumination of a continuous-wave laser beam enables structural modifications to be localized to the contact area on the glass surface...
October 18, 2016: Nanoscale
F Alpeggiani, S D'Agostino, D Sanvitto, D Gerace
We report theoretical evidence that bulk nonlinear materials weakly interacting with highly localized plasmonic modes in ultra-sub-wavelength metallic nanostructures can lead to nonlinear effects at the single plasmon level in the visible range. In particular, the two-plasmon interaction energy in such systems is numerically estimated to be comparable with the typical plasmon linewidths. Localized surface plasmons are thus predicted to exhibit a purely nonclassical behavior, which can be clearly identified by a sub-Poissonian second-order correlation in the signal scattered from the quantized plasmonic field under coherent electromagnetic excitation...
October 18, 2016: Scientific Reports
Keiko Tawa, Shohei Yamamura, Chisato Sasakawa, Izumi Shibata, Masatoshi Kataoka
Plasmonic chip was applied to the live cancer cell imaging. The epithelial cell adhesion molecule (EpCAM) is a surface marker that can be used to classify breast cancer cell lines into distinct differentiation states. EpCAM and the nuclei of two kinds of living breast cancer cells, MDA-MB231 and MCF-7, were stained with allophycocyanin (APC)-labeled anti-EpCAM antibody and 4,6-diamidino-2-phenylindole (DAPI), respectively, and the cells were scattered on either a plasmonic chip (metal-coated wavelength-scale grating substrate) or a control glass slide...
October 18, 2016: ACS Applied Materials & Interfaces
Marco Sturaro, Enrico Della Gaspera, Niccolò Michieli, Carlo Cantalini, Seyed Mahmoud Emamjomeh, Massimo Guglielmi, Alessandro Martucci
Highly doped wide band gap metal oxides nanocrystals have recently been proposed as building blocks for applications as transparent electrodes, electrochromics, plasmonics, and optoelectronics in general. Here we demonstrate the application of gallium doped zinc oxide (GZO) nanocrystals as novel plasmonic and chemiresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO nanocrystals with a tunable surface plasmon resonance in the near infrared are obtained using a colloidal heat-up synthesis...
October 18, 2016: ACS Applied Materials & Interfaces
Yu-Hong Cheng, Yue Zhang, Siu-Leung Chau, Samuel Kin-Man Lai, Ho-Wai Tang, Kwan-Ming Ng
Metal alloy nanoparticles (NPs) offer a new combination of unique physicochemical properties based on their pure counterparts, which can facilitate the development of novel analytical methods. Here, we demonstrated that Ag-Au alloy NPs could be utilized for optical and mass spectrometric imaging of latent fingerprints (LFPs) with improved image contrast, stability, and detection sensitivity. Upon deposition of Ag-Au alloy NPs (Ag:Au = 60:40% wt), ridge regions of the LFP became amber-coloured, while the groove regions appeared purple-blue...
October 17, 2016: ACS Applied Materials & Interfaces
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