Search results for "Gold nanoparticle"
showing 10 items of 54 documents
Ascorbic Acid determination using linear sweep voltammetry on flexible electrode modified with gold nanoparticles and reduced graphene oxide
2020
Indium tin oxide (ITO) coated on flexible polyethylene terephthalate (PET) substrate electrode was modified with reduced graphene oxide and gold nanoparticles by simple co-electrodeposition performed at -0.8 V vs SCE for 200 s. All samples were characterized by electron scan microscopy. The as prepared electrode was used as electrochemical sensor to selective detection of ascorbic acid using linear sweep voltammetry. Excellent results were obtained in a linear range from 20 to 150 µM of ascorbic acid with a limit of detection of about 3.1 µM (S/N=3.3). The sensors have a reproducibility of about 5.5% and also show high selectivity towards different interferents such as chlorine, calcium, ma…
Structure and the metal-support interaction of the Au/Mn oxide catalysts
2010
Gold catalysts with loading 1 and 10 wt % were-prepared by deposition precipitation method with urea over mesoporous manganese oxide, obtained through a surfactant-assisted procedure by using cetyltrimethylammonium bromide (CTAB), followed by treatment with sulphuric acid. For comparison, Au(10 wt %) was also deposited over commercial CeO2 and SiO2 supports. The materials were characterized by XRD and EXAFS at the Mn K and Au L-III edges and XPS. Moreover, the analyses were performed on the samples treated under 1%CO/He, at 250 degrees C for 90 min. The structural and surface results of the as prepared manganese oxide confirmed the formation of gamma-MnO2 along with some amorphous Mn3O4 upo…
Gold Nanoparticles on 3D-Printed Filters : From Waste to Catalysts
2019
Three-dimensionally printed solid but highly porous polyamide-12 (PA12) plate-like filters were used as selective adsorbents for capturing tetrachloroaurate from acidic solutions and leachates to prepare PA12–Au composite catalysts. The polyamide-adsorbed tetrachloroaurate can be readily reduced to gold nanoparticles by using sodium borohydride, ascorbic acid, hydrogen peroxide, UV light, or by heating. All reduction methods led to polyamide-anchored nanoparticles with an even size distribution and high dispersion. The particle sizes were somewhat dependent on the reduction method, but the average diameters were typically about 20 nm. Particle sizes were determined by using a combination of…
Gold recycling at laboratory scale: from nanowaste to nanospheres
2019
The market for products based on nanotechnology, and with it the use of nanomaterials and the generation of nanowaste, increases day by day. Among the vast variety of nanomaterials available, gold nanoparticles (AuNPs) are among the most studied and applied in commercial products. This current situation requires both the development of recovery methods to reduce the amount of nanowaste produced, and new synthetic methods that allow the reuse of recovered gold for new nanomaterial production, keeping in mind both economical and ecological considerations. In this work, a methodology to recover gold from aqueous laboratory nanowaste and transform it into an aqueous HAuCl4 solution was develope…
Nanophase Segregation of Self-Assembled Monolayers on Gold Nanoparticles
2017
International audience; Nanophase segregation of a bi-component thiol self-assembled monolayer is predicted using atomistic molecular dynamics simulations and experimentally confirmed. The simulations suggest the formation of domains rich in acid-terminated chains, on one hand, and of domains rich in amide-functionalized ethylene glycol oligomers, on the other hand. In particular, within the amide-ethylene glycol oligomers region, a key role is played by the formation of inter-chain hydrogen bonds. The predicted phase segregation is experimentally confirmed by the synthesis of 35 and 15 nm gold nanoparticles functionalized with several binary mixtures of ligands. An extensive study by trans…
Surface plasmon subwavelength optics.
2003
International audience; Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons- in particular their interaction with light-can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.
Synthesis and physico-chemical characterization of gold nanoparticles softly coated by AOT
2006
Size-controlled gold nanoparticles/surfactant stable systems were prepared by the combined action of the solvated metal atom dispersion (SMAD) technique and confinement in anhydrous sodium bis(2-ethylhexyl)sulfosuccinate (AOT) micellar solution. From liquid samples, by evaporation of the organic solvent, solid gold nanoparticle-surfactant liquid crystals composites were obtained. Sample characterization was performed by X-ray diffraction (SAXS and WAXS), XPS spectroscopy and UV-vis-NIR spectroscopy. All experimental data consistently revealed the coexistence of two gold nanoparticle size populations: bigger nanoparticles (size 20-50 angstrom) and smaller ones (size of few angstrom). The two…
Donor–Acceptor Interfaces by Engineered Nanoparticles Assemblies for Enhanced Efficiency in Plastic Planar Heterojunction Solar Cells
2016
Precisely positioning functionalized gold nanoparticles assemblies at planar donor-acceptor interfaces results in 14-fold enhancement of power conversion efficiency in P3HT/PCBM organic solar cells on plastic (ITO/PET) substrates. This result has been achieved by employing naphthalenethiol-capped gold nanoparticles (NT-Au-NPs) produced by laser ablation in liquid and size varied in the 10-30 nm range. Upon surface functionalization with the aromatic thiol, these particles self-assemble in submicrometer aggregates, which give increased light scattering. When these aggregates are deposited in the planar heterojunction between the donor and the acceptor systems, the localized scattering leads …
Photothermal Ablation of Cancer Cells Using Folate-Coated Gold/ Graphene Oxide Composite
2017
Objective: A new tumor targeted polymer-coated gold/graphene hybrid has been developed for achieving simultaneously thermoablation and chemoterapy of folate receptor-positive cancer cells. Methods: The gold/graphene hybrid was prepared by depositing gold nanospheres onto graphene oxide and coating it with an inulin-folate conjugate. Paclitaxel was loaded by sonication. The hybrid was characterized by UV-Vis spectroscopy, DSC analysis and SEM microscopy. The cytotoxicity, thermoablation and anticancer activity were evaluated in vitro on MCF-7 and 16 HBE. Results: In vitro tests showed that the paclitaxel-loaded hybrid improved the effectiveness of the drug especially after photothermal treat…
Development of a three-dimensional cell culture system based on microfluidics for nuclear magnetic resonance and optical monitoring
2014
A new microfluidic cell culture device compatible with real-time nuclear magnetic resonance (NMR) is presented here. The intended application is the long-term monitoring of 3D cell cultures by several techniques. The system has been designed to fit inside commercially available NMR equipment to obtain maximum readout resolution when working with small samples. Moreover, the microfluidic device integrates a fibre-optic-based sensor to monitor parameters such as oxygen, pH, or temperature during NMR monitoring, and it also allows the use of optical microscopy techniques such as confocal fluorescence microscopy. This manuscript reports the initial trials culturing neurospheres inside the micro…