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Haas P.,Institute of Physics | Then P.,Physikalisches Institute | Wild A.,Institute of Physics | Grange W.,Institute Jacques Monod | And 6 more authors.
Analytical Chemistry | Year: 2010

The applicability of single-molecule fluorescence assays in liquids is limited by diffusion to concentrations in the low picomolar range. Here, we demonstrate quantitative single-molecule detection at attomolar concentrations within 1 min by excitation and detection of fluorescence through a single-mode optical fiber in presence of turbulent flow. The combination of high detectability and short measurement times promises applications in ultrasensitive assays, sensors, and point-of-care medical diagnostics. © 2010 American Chemical Society. Source

Collins G.,Tyndall National Institute | Collins G.,Center for Research on Adaptive Nanostructures and Nanodevices | Fleming P.,Tyndall National Institute | Fleming P.,Center for Research on Adaptive Nanostructures and Nanodevices | And 9 more authors.
Chemistry of Materials | Year: 2010

The ambient stability and surface coverage of halogen (Cl, Br, and I) passivated germanium nanowires were investigated by X-ray photoelectron and X-ray photoelectron emission spectroscopy. After exposure to air for 24 h, the stability of the halogen-terminated Ge nanowire surfaces toward reoxidation was found to improve with the increasing size of the halogen atoms, i.e., I>Br>Cl. Halogen termination was effective in removing the native Ge oxide (GeOx) and could also be utilized for further functionalization. Functionalization of the halogenated Ge nanowires was investigated using alkyl Grignard reagents and alkanethiols. The stability of the alkyl and alkanethiol passivation layers from the different halogen-terminated surfaces was investigated by X-ray photoelectron spectroscopy and attenuated total reflectance infrared spectroscopy. Alkanethiol functionalized nanowires showed greater resistance against reoxidation of the Ge surface compared to alkyl functionalization when exposed to ambient conditions for 1 week. ©2010 American Chemical Society. Source

Kumar S.,Center for Research on Adaptive Nanostructures and Nanodevices | Kumar S.,Trinity College Dublin | Rezvani E.,Center for Research on Adaptive Nanostructures and Nanodevices | Rezvani E.,Trinity College Dublin | And 3 more authors.
Nanotechnology | Year: 2012

We present a graphene resist interlacing process (GRIP) to sandwich graphene between polymer lines in a cloth-like fashion, making it more accessible for experiments and applications. We demonstrate the handling of large-area graphene in this way. Here, GRIP is used to fabricate supports for transmission electron microscopy. These supports improve the imaging quality of nanoparticles, as we show by comparison to imaging on standard lacey carbon supports. © 2012 IOP Publishing Ltd. Source

Murphy F.A.,Queens Medical Research Institute | Poland C.A.,Queens Medical Research Institute | Poland C.A.,Institute of Occupational Medicine | Duffin R.,Queens Medical Research Institute | And 19 more authors.
American Journal of Pathology | Year: 2011

The fibrous shape of carbon nanotubes (CNTs) raises concern that they may pose an asbestos-like inhalation hazard, leading to the development of diseases, especially mesothelioma. Direct instillation of long and short CNTs into the pleural cavity, the site of mesothelioma development, produced asbestos-like length-dependent responses. The response to long CNTs and long asbestos was characterized by acute inflammation, leading to progressive fibrosis on the parietal pleura, where stomata of strictly defined size limit the egress of long, but not short, fibers. This was confirmed by demonstrating clearance of short, but not long, CNT and nickel nanowires and by visualizing the migration of short CNTs from the pleural space by single-photon emission computed tomographic imaging. Our data confirm the hypothesis that, although a proportion of all deposited particles passes through the pleura, the pathogenicity of long CNTs and other fibers arises as a result of length-dependent retention at the stomata on the parietal pleura. Copyright © 2011 American Society for Investigative Pathology. Source

Keeley G.P.,CNRS Molecular Chemistry Department | Keeley G.P.,Center for Research on Adaptive Nanostructures and Nanodevices | Keeley G.P.,Trinity College Dublin | O'Neill A.,Center for Research on Adaptive Nanostructures and Nanodevices | And 7 more authors.
Physical Chemistry Chemical Physics | Year: 2011

The electrochemical detection of NADH is of considerable interest because it is required as a cofactor in a large number of dehydrogenase-based biosensors. However, the presence of oxygenated functionalities on the electrode often causes fouling due to the adsorption of the oxidised form, NAD +. Here we report an electroanalytical NADH sensor based on DMF-exfoliated graphene. The latter is shown to have a very low oxygen content, facilitating the exceptionally stable and sensitive detection of this important analyte. © 2011 the Owner Societies. Source

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