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Journal of Thermal Analysis and Calorimetry
Authors: Eudes Lorençon, Rodrigo G. Lacerda, Luiz O. Ladeira, Rodrigo R. Resende, André S. Ferlauto, Ulf Schuchardt, and Rochel M. Lago

significantly when the metal impurity of the sample increased. Iijima et al. [ 13 ] reported that SWNT can be purified by using gold nanoparticles deposited on carbonaceous soot followed by controlled oxidation with O 2 . An overall analysis of these reports

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Journal of Thermal Analysis and Calorimetry
Authors: S. Papp, L. Kőrösi, B. Gool, T. Dederichs, P. Mela, M. Möller, and I. Dékány

Abstract  

Gold nanoparticles (Au NPs) were prepared by the reduction of HAuCl4 acid incorporated into the polar core of poly(styrene)-block-poly(2-vinylpyridine) (PS-b-P2VP) copolymer micelles dissolved in toluene. The formation of Au NPs was controlled using three reducing agents with different strengths: hydrazine (HA), triethylsilane (TES), and potassium triethylborohydride (PTB). The formation of Au NPs was followed by transmission electron microscopy, UV–Vis spectroscopy, isothermal titration calorimetry (ITC), and dynamic light scattering (DLS). It was found that the strength of the reducing agent determined both the size and the rate of formation of the Au NPs. The average diameters of the Au NPs prepared by reduction with HA, TES, and PTB were 1.7, 2.6, and 8 nm, respectively. The reduction of Au(III) was rapid with HA and PTB. TES proved to be a mild reducing agent for the synthesis of Au NPs. DLS measurements demonstrated swelling of the PS-b-P2VP micelles due to the incorporation of HAuCl4 and the reducing agents. The original micellar structure rearranged during the reduction with PTB. ITC measurements revealed that some chemical reactions besides Au NPs formation also occurred in the course of the reduction process. The enthalpy of formation of Au NPs in PS-b-P2VP micelles reduced by HA was determined.

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Gold nanoparticles (AuNPs) and l-cysteine (l-cys), in order, as first and second layer were coated on the surface of a commercial thin-layer chromatography (TLC) plate. This assemble has been used as a new substrate for direct resolution of propranolol enantiomers based on the ordinary TLC technique. The effect of concentrations of the involved chemicals, time periods of the required processes, pH of the sample solutions, as well as the effects of different coating protocols on the resolution of the enantiomers, were investigated in order to find the optimized separation conditions. The results showed that 10.0 mM copper(II) acetate, in 70% ethanol-water adjusted at pH = 6.3, was suitable for being used as the mobile phase. The AuNPs with the average size of 15 nm and l-cys solution with a concentration of 10.0 mM and pH = 8.1 had been chosen for impregnating TLC plates.

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. Luan , Y.X. , Chen , Z.B. , Xie , G. , Chen , J.Y. , Lu , A.X. , Li , C. , Fu , H.L. , Ma , Z.H. , Wang , J.H. 2015 . Rapid visual detection of aflatoxin B1 by label-free aptasensor using unmodified gold nanoparticles . J

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Abstract  

Gold nanoparticles (Au-NPs) were prepared by a surfactant-free single-phase reduction of hydrogen tetrachloroaurate(III) hydrate in the presence of different organic thiol ligands. Sizes, size distributions, and crystallinity of the Au-NPs were determined by high-resolution transmission electron microscopy and powder X-ray diffraction, whereas thermogravimetric analysis provided information on the organic ligand-to-gold ratios as well as amounts of contaminants. A systematic decrease in size with increasing conical bulk of the thiolate ligand is observed but large size distributions and contamination of the generated Au-NPs prohibit detailed mechanistic studies. A first-generation Fréchet dendron thiol produced the smallest and cleanest Au-NPs of the narrowest size distribution.

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The real-time monitoring of the adsorption kinetic of antibody onto polyethylene terephthalate (PET) modified with gold nanoparticles (NPs) is performed into a dielectric flow microchannel. The principle is based on the microelectrode–dielectric interface excitation by a modulated voltage excitation through the dielectric layer with high frequency range. The set-up configuration using a homemade current-to-voltage converter has been developed for fast monitoring of biomolecule adsorption without direct electrical contact of microelectrodes with the microchannel flow. The change in the interfacial admittance, related to the output voltage measured through the microchip, during antibody incubation, gives information on the kinetics involved while antibodies are adsorbed at the interface. An example of adsorption on PET modified with gold NPS was taken. Experimental data were fit with the Langmuir equation and a good correlation was obtained with this latter, where the equilibrium constant, K, was found as 1.55 × 108 M−1 with a limit of detection for antibody concentration without depletion equal to 8.25 nM.

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, which corresponds to lattice planes (120), (121), (022), (231), (241), (251) and (332) with diffraction peaks around 2ϑ = 25.3, 30.7, 40.1, 48.0, 55.2, 64.5, 70.5° (JCPDS No. 12-1360). The diffraction peaks of the gold nanoparticles were too small to be

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Abstract  

The thermal decomposition characteristics of gold acetate to produce gold nanoparticles were investigated. A rapid and violent fragmentation of the gold acetate particles was observed at approximately 103±20°C when a rapid heating rate of 25°C min−1 was used, leading to formation of nanosized spherical and partially coalesced gold particles. Particle size analysis was used to investigate possible relationships between the gold acetate crystallite size and the gold nanoparticles produced by thermal decomposition. The results indicate rapid (<0.14 ms) coalescence of the gold particles occurs for fragments in close proximity.

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Acta Physiologica Hungarica
Authors: Teodora Mocan, S. Clichici, L. Agoşton-Coldea, L. Mocan, Ş Şimon, I. Ilie, A. Biriş, and Adriana Mureşan

Chithrani BD, Ghazani AA, Chan WC: Determining the size and shape dependence of gold nanoparticle uptake into mammalian cells. Nano Lett. 6(4), 662–668 (2006) Chan W.C. Determining the

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probe and gold nanoparticles. Biosens. Bioelectron. , 26 , 3806–3811. Akkoca A. Development of an impedimetric aflatoxin M1 biosensor based on a DNA probe and gold nanoparticles

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