Showing papers by "Mirko Prato published in 2008"
TL;DR: In this article, the optical response of self-assembled monolayers (SAMs) deposited from the liquid phase on well characterized, (111)-textured gold films based on the use of in situ and ex situ optical spectroscopic ellipsometry was investigated.
Abstract: We have investigated the optical response of thiolate self-assembled monolayers (SAMs) deposited from the liquid phase on well characterized, (111)-textured gold films based on the use of in situ and ex situ optical spectroscopic ellipsometry We considered SAMs formed by several molecules with thiol functionality, focusing on the octadecanethiol (C18) SAM model system We were able to show the tiny spectroscopic variations induced by the monolayer thick films with great reproducibility and high signal-to-noise ratio We identified spectral features related to the alkyl chain and to the S−Au interface, providing a reliable spectral “fingerprint” of the formation of densely packed thiolate layers By comparing data with simulations based on several effective models developed within the framework of Fresnel approach, we identified the main optical features related to the thiolate interface and in particular an absorption band whose spectral weight increases regularly from 500 nm toward the IR limit We also
69 citations
TL;DR: The measurements show that nicely organized HSC9SH SAMs can be obtained in n-hexane provided that N2-degassed solutions are used and all preparation steps are performed in the absence of ambient light.
Abstract: A study of the self-assembly of nonane-alkanedithiol monolayers on gold in n-hexane and ethanol solvents is presented. Self-assembled monolayers (SAMs) are characterised by reflection–absorption infrared spectroscopy (RAIRS), sum frequency generation (SFG) and spectroscopic ellipsometry (SE) measurements. Data obtained for alkanethiols SAMs are also shown for comparison. The measurements show that nicely organized HSC9SH SAMs can be obtained in n-hexane provided that N2-degassed solutions are used and all preparation steps are performed in the absence of ambient light. SFG measurements show that these SAMs have free standing SH groups. Use of an un-degassed and/or light-exposed n-hexane solutions leads to a worse layer organization. Preparation in ethanol, even in degassed solutions with processing in the dark, leads to poorly organized layers and no sign of free –SH groups was observed.
61 citations
TL;DR: This work has shown that upon adsorption of commonly available proteins onto the hydrophobic and long-range ordered surface of pyrolytic graphite, proteins lose their native folding and polypeptide chains re-assemble on the surface in a layered fashion, forming a molecular bilayer.
Abstract: Molecular layers patterned on the nanoscale, with long-range order properties extending over the microscopic scale, have been obtained upon adsorption of commonly available proteins onto the hydrophobic and long-range ordered surface of pyrolytic graphite (HOPG). Proteins lose their native folding and polypeptide chains re-assemble on the surface in a layered fashion, forming a molecular bilayer. This behaviour is rather general since it is observed for different proteins irrespective of their specific structural properties.
24 citations
TL;DR: In this paper, real-time Spectroscopic Ellipsometry (SE) was used to discriminate the under-potential (UP) and over potential (OP) regimes.
Abstract: We have studied Cu electrodeposition on well defined Au films using real time Spectroscopic Ellipsometry (SE). SE allows to discriminate the under-potential (UP) and over-potential (OP) regimes. In the UP regime, tiny yet reproducible variations of Ψ and Δ parameters indicate the formation of two phases with slightly different optical behavior. The phase at the largest coverage is assigned to a Cu monolayer. The SE response in the OP regime shows a marked dependence on the potential scan rate. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
15 citations
TL;DR: Multiwalled carbon nanotubes made highly water-dispersible by organic functionalization and radiolabeled with Indium-111 were shown to translocate through the kidney glomerular filter and accumulate in the bladder before clearance in the urine.
Abstract: Multiwalled carbon nanotubes (MWNTs) made highly water-dispersible by organic functionalization and radiolabeled with Indium-111 were shown to translocate through the kidney glomerular filter. On p. 225, multinational, multicenter research led by Kostas Kostarelos on dynamic imaging and tissue distribution of MWNTs in live animals is presented. The cover image presents a single plane single photon computed tomography whole body image of a rat following intravenous injection with the In-111 labeled MWNTs as seen through a 3D carbon NT projection. The radioactivity from carbon NTs was mainly localized in the kidneys, and accumulated in the bladder before clearance in the urine.
4 citations
01 Oct 2008
TL;DR: It is shown that various types of functionalized-carbon nanotubes (f-CNT) exhibit a capacity to be uptaken by a wide range of cells and can intracellularly traffick through different cellular barriers.
Abstract: The interaction between cells and carbon nanotubes (CNT) is a critical issue that will determine any future biological application of such structures. In this communication we will show that various types of functionalized-carbon nanotubes (f-CNT) exhibit a capacity to be uptaken by a wide range of cells (prokaryotic and eukaryotic) and can intracellularly traffick through different cellular barriers([1, 2]). The mechanism by which f-CNT are able to cross cell membranes and deliver their cargo will also be discussed. Energy-independent mechanisms are explained based on the cylindrical shape and high aspect ratio of f-CNT that can allow their penetration through the plasma membrane, similar to a 'nanosyringe'([3]).