1,721,088 research outputs found
The puzzle of toxicity of gold nanoparticles. The case-study of HeLa cells
No full textBecause of the growing interest of gold nanoparticles in biomedical and biotechnological applications, their toxicity is becoming an increasingly important issue and, in the last few years, there has been continuously expanding research activity in this field. However, due to the intrinsic complexity of the problem, together with the lack in the standardization of the experimental procedures, there is to date a large scattering of the results that still prevents reaching a general consensus of the possible toxic effects of gold nanoparticles in biological systems of increasing complexity (cell membrane, cells, tissues, organs and human body). The strong need to systematize the data suggests employing an appropriate metric, as far as the particle concentration is concerned, that could help in comparing and organizing the available data in a more intelligible scenario. In this note, some recent literature data on the viability of HeLa cells exposed to differently functionalized gold nanoparticles have been analyzed on the basis of a metric based on the numerical particle concentration (number of particles per unit volume of cell culture) that, to a certain extent, takes into account both the size and the shape of nanoparticles. This analysis offers a much more intelligible behavior than the one based on metrics that considers mass concentration (molar concentration) or particle size. At least, in the particular case of HeLa cells, the analysis of the data shows that differently functionalized gold nanoparticles behave similarly and that the different surface coating of the different nanoparticles considered defines the range of particle concentration where toxic effects begin. This kind of analysis could furnish some albeit preliminary suggestions towards an appropriate method to study gold nanoparticle toxicity
Functionalized platinum nanoparticles with surface charge trigged by pH: Synthesis, characterization and stability studies
No full textIn this work, the synthesis and characterization of functionalized platinum nanoparticles (PtNPs) have been investigated. PtNPs were obtained by a wet redox procedure using 2-diethylaminoethanethiol hydrochloride (DEA) as capping agent. By varying the Pt/thiol molar ratio, monodispersed and stable particles with diameters in the range of 3-40 nm were isolated. The amino functionality allows neutral particles to be obtained in basic water solution and positive charged nanoparticles in neutral or acidic water solution (pH 7-2), as confirmed by DLS and ζ-potential measurements. FTIR spectroscopy, FE-SEM, DLS and ζ-potential measurements confirmed the size and showed long term water stability (up to three months) of the colloidal system
NEXAFS study of a Pt-containing rod-like organometallic polymer (Pt-DEBP). Molecular orientation onto HOPG, Au/Si(111), Cr/Si(111) and Si(111) surfaces
No full textFunctionalized platinum nanoparticles with surface charge trigged by pH: synthesis, characterization and stability studies
Full text linkIn this work, the synthesis and characterization of functionalized platinum nanoparticles (PtNPs) have been investigated. PtNPs were obtained by a wet redox procedure using 2-diethylaminoethanethiol hydrochloride (DEA) as capping agent. By varying the Pt/thiol molar ratio, monodispersed and stable particles with diameters in the range of 3–40 nm were isolated. The amino functionality allows neutral particles to be obtained in basic water solution and positive charged nanoparticles in neutral or acidic water solution (pH 7–2), as confirmed by DLS and ζ-potential measurements. FTIR spectroscopy, FE-SEM, DLS and ζ-potential measurements confirmed the size and showed long term water stability (up to three months) of the colloidal system
Magnetic Nanoparticles as an Efficient Tool for Analyte Extraction: Challenges and New Opportunities
No full textNanomaterials are introducing changes in many industrial areas, allowing someparticular characteristics such as the type ofmaterial, and the size, shape, morphology, chemical composition and molecular configuration of the materials to be managed. Moreover, the use of nanomaterials has expanded rapidly, from the first applications in the materials field, to multiple sectors such as medical and pharmaceutical, biological, environmental, electronic and recently agro-food
Hydrophilic gold nanoparticles as multimodal agents for plasmonic nanomedicine. Salamone TA., B. Pennacchi B, Mercurio M, Cerra S, Marotta S, Mrmic S, Alimandi M, Visco V, Taurino M, Trivedi P, I. Fratoddi I, Anastasiadou E
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Synthesis and characterization of stereoregular π-conjugated polyarylenynes, (-Ar-(E)-CH=CHC≡C-)n, decorated with branched bis-alkoxy side chains
No full textNovel poly(p-phenyleneethynylenevinylene)s (PPEV) have been synthesized by step-growth oligomerization of 2,5-diethynyl-1,4-dialkoxybenzene monomers promoted by the ruthenium pre-catalyst [{RuCl(μ-Cl)(η6-p-cymene)}2] in the solvent mixture AcOH/CH2Cl2. The presence of the branched side chains 2-ethylhexyloxy or 3,7-dimethyloctyloxy in the phenylene unit allows for the formation of soluble π-conjugated short polymers, with slightly increased degree of polymerization (Xn = 5 - 10) and red-shifted photophysical properties (λem ≅ 515 nm in CHCl3) with respect to the analogues with linear alkoxy side chains. The aggregation properties of the polymer with 2-ethylhexyloxy groups have been investigated by an osmosis driven procedure, yielding nanospheres of different size depending on the adapted solvent/nonsolvent mixture
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