67 research outputs found

    Porosity-moderated ultrafast electron transport in Au nanowire networks

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    We demonstrate for first time the ultrafast properties of a newly formed porous Au nanostructure. The properties of the porous nanostructure are compared with those of a solid gold film using time-resolved optical spectroscopy.The experiments suggest that under the same excitation conditions the relaxation dynamics are slower in the former. Our observations are evaluated by simulations based on a phenomenological rate equation model. The impeded dynamics has been attributed to the porous nature of the structure in the networks, which results in reduced efficiency during the dissipation of the laser-deposited energy. Importantly,the porosity of the complex three-dimensional nanostructure is introduced as a geometrical control parameter of its ultrafast electron transport

    Hyperspectral darkfield microscopy of single hollow gold nanoparticles for biomedical applications

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    Hyperspectral microscopy is a versatile method for simultaneous spatial and spectroscopic characterization of nonfluorescent samples. Here we present a hyperspectral darkfield imaging system for spectral imaging of single nanoparticles over an area of 150 × 150 µm2 and at illumination intensities compatible with live cell imaging. The capabilities of the system are demonstrated using correlated transmission electron microscopy and single-particle optical studies of colloidal hollow gold nanoparticles. The potential of the system for characterizing the interactions between nanoparticles and cells has also been demonstrated. In this case, the spectral information proves a useful improvement to standard darkfield imaging as it enables differentiation between light scattered from nanoparticles and light scattered from other sources in the cellular environment. The combination of low illumination power and fast integration times makes the system highly suitable for nanoparticle tracking and spectroscopy in live-cell experiments

    Chemically induced self-assembly of spherical and anisotropic inorganic nanocrystals

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    The self-assembly of inorganic nanoparticles is a research area of great interest aiming at the fabricationof unique mesostructured materials with intrinsic properties. Although many assembly strategies have been reportedover the years, chemically induced self-assembly remains one of the dominant approaches to achieve a high levelof nanoparticle organization. In this feature article we review the latest developments in assembly drivenby the active manipulation of nanoparticle surface

    Enzymatic manipulation of DNA/gold nanoparticle assemblies

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    EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Preparation of peptide functionalized gold nanoparticles using one pot EDC/sulfo-NHS coupling

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    Although carbodiimides and succinimides are broadly employed for the formation of amide bonds(i.e. in aminoacid coupling), their use in the coupling of peptides to water-soluble carboxylicterminated colloidal gold nanoparticles remains challenging. In this paper, we present anoptimization study for the successful coupling of the KPQPRPLS peptideto spherical and rod-likecolloidal gold nanoparticles. We show that the concentration, reaction time and the chemicalenvironment are all critical to achieve the formation of robust, peptide-coated colloidalnanoparticles. Agarose gel electrophoresis was used for the characterization of conjugates

    Laser-induced damage and recovery of plasmonically targeted human endothelial cells

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    Laser-induced techniques that employ the surface plasmon resonances of nanoparticles have recently been introduced as an effective therapeutic tool for destroying tumor cells. Here, we adopt a low-intensity laser-induced technique to manipulate the damage and repair of a vital category of noncancerous cells, human endothelial cells. Endothelial cells construct the interior of blood vessels and play a pivotal role in angiogenesis. The degree of damage and repair of the cells is shown to be influenced by laser illumination in the presence of gold nanoparticles of different morphologies, which either target the cellular membrane or are endocytosed. A pronounced influence of the plasmonic nanoparticle laser treatment on the expression of critical angiogenic genes is shown. Our results show that plasmon-mediated mild laser treatment, combined with specific targeting of cellular membranes, enables new routes for controlling cell permeability and gene regulation in endothelial cells.<br/
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