Search results for "surface plasmon resonance"
showing 10 items of 208 documents
Surface plasmons and vibrations of self-assembled silver nanocolumns
2006
6 pags. ; 5 figs. 1 tab.
Plasmonic Nanosensors for Simultaneous Quantification of Multiple Protein–Protein Binding Affinities
2014
Most of current techniques used for the quantification of protein-protein interactions require the analysis of one pair of binding partners at a time. Herein we present a label-free, simple, fast, and cost-effective route to characterize binding affinities between multiple macromolecular partners simultaneously, using optical dark-field spectroscopy and individual protein-functionalized gold nanorods as sensing elements. Our NanoSPR method could easily become a simple and standard tool in biological, biochemical, and medical laboratories.
2NH and 3OH are crucial structural requirements in sphingomyelin for sticholysin II binding and pore formation in bilayer membranes.
2013
AbstractSticholysin II (StnII) is a pore-forming toxin from the sea anemone Stichodactyla heliantus which belongs to the large actinoporin family. The toxin binds to sphingomyelin (SM) containing membranes, and shows high binding specificity for this lipid. In this study, we have examined the role of the hydrogen bonding groups of the SM long-chain base (i.e., the 2NH and the 3OH) for StnII recognition. We prepared methylated SM-analogs which had reduced hydrogen bonding capability from 2NH and 3OH. Both surface plasmon resonance experiments, and isothermal titration calorimetry measurements indicated that StnII failed to bind to bilayers containing methylated SM-analogs, whereas clear bind…
Sizzled Is Unique among Secreted Frizzled-related Proteins for Its Ability to Specifically Inhibit Bone Morphogenetic Protein-1 (BMP-1)/Tolloid-like …
2012
BMP-1/tolloid-like proteinases (BTPs) are major enzymes involved in extracellular matrix assembly and activation of bioactive molecules, both growth factors and anti-angiogenic molecules. Although the control of BTP activity by several enhancing molecules is well established, the possibility that regulation also occurs through endogenous inhibitors is still debated. Secreted frizzled-related proteins (sFRPs) have been studied as possible candidates, with highly contradictory results, after the demonstration that sizzled, a sFRP found in Xenopus and zebrafish, was a potent inhibitor of Xenopus and zebrafish tolloid-like proteases. In this study, we demonstrate that mammalian sFRP-1, -2, and …
Formation of irreversibly bound annexin A1 protein domains on POPC/POPS solid supported membranes
2008
AbstractThe specific interaction of annexin A1 with phospholipid bilayers is scrutinized by means of scanning force and fluorescence microscopy, quartz crystal microbalance, ellipsometry, and modeled by dynamic Monte Carlo simulations. It was found that POPC/POPS bilayers exhibit phase separation in POPC- and POPS-enriched domains as a function of Ca2+ concentration. Annexin A1 interacts with POPC/POPS bilayers by forming irreversibly bound protein domains with monolayer thickness on POPS-enriched nanodomains, while the attachment of proteins to the POPC-enriched regions is fully reversible. A thorough kinetic analysis of the process reveals that both, the binding constant of annexin A1 at …
Monitoring the formation of biosilica catalysed by histidine-tagged silicatein.
2004
Surface bound silicatein retains its biocatalytic activity, which was demonstrated by monitoring the immobilisation of silicatein using a histidine-tag chelating anchor and the subsequent biosilicification of SiO(2) on surfaces by surface plasmon resonance spectroscopy, atomic force microscopy and scanning electron microscopy.
An advance Towards the Synthesis of Ag Nanorod Arrays with Controlled Surface Roughness for SERS Substrates
2016
An innovative approach to produce silver nanorod (NRs) arrays with controlled morphological parameters and surface roughness is presented. The Ag NRs were obtained using a three-stage fabrication process based on the electron beam exposure of a metal-polymer nanocomposite resist on a transparent substrate and development, a post bake and then a series of non-electrochemical metallization steps. After each step the evolution of the Ag NRs was characterized by scanning electron microscopy (SEM) for morphology and optical transmittance (T) measurements for Localized Surface Plasmon Resonance (LSPR). The transmittance measurements were interpreted using models based on the Finite Element Method…
Au-PVA Nanocomposite Negative Resist for One-Step Three-Dimensional e-Beam Lithography
2009
Au nanoparticles are synthesized in situ upon the electron beam exposure of a poly(vinyl alcohol) (PVA) thin film containing Au(III). The e-beam-irradiated areas are insoluble in water (negative-tone resist), and Au-PVA nanocomposite patterns with a variable profile along the structure can be thus generated (3D lithography) in a single step. A local characterization of the generated patterns is performed by high-resolution transmission electron microscopy and UV-vis localized surface plasmon resonance microspectroscopy. This characterization confirms the presence of crystalline nanoparticles and aggregates.
Green synthesis and characterizations of silver and gold nanoparticles using leaf extract of Rosa rugosa
2010
Abstract Metal nanostructures have unusual physicochemical properties and biological activities compared to their bulk parent materials. Thus in recent years a number of physical, chemical and biological techniques were applied for the development of metal nanoparticles (NP). Here we have synthesized silver and gold nanoparticles (AgNPs and AuNPs) by using leaves extracts of Rosa rugosa . Surface plasmon resonance spectra for silver and gold are obtained at 451 and 578 nm with brown yellow and pink-red color, respectively. AgNPs and AuNPs vary in size according to different leaves extract and metal concentration used for the synthesis. Different instrumental techniques were applied to chara…
Single Out-of-Resonance Dielectric Nanoparticles as Molecular Sensors.
2021
Light scattering from single nanoparticles and nanostructures is a commonly used readout method for nanosensors. Increasing the spectral sensitivity of resonant nanosensors to changes in their local surrounding has been the focus of many studies. Switching from spectral to intensity monitoring allows one to investigate nonresonant or out-of-resonance dielectric nanoparticles. Here, we systematically compared such dielectric silica nanoparticles with plasmonic gold nanorods by deriving analytical expressions and by performing experiments. The experiments show a similar sensitivity for the detection of an adsorbate layer for both particle types, which is in good agreement with theory. The fla…