Search results for "nanoparticle"

Super Resolved Holographic Configurations

2014

Enhanced H2O2 production over Au-rich bimetallic Au-Pd nanoparticles on ordered mesoporous carbons

2015

1 figures, 3 tables.-- © 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical …

2000

Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. Mossbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the Mossbauer spectra on temperature and particle size is explai…

Enhanced Efficiency of Organic Solar Cells by Thiol-capped Au-Nanoparticles

2015

In this work, we present a study on the effect of thiol-capped AuNPs of various sizesin an organic solar cell.AuNPs have been obtained by laser ablation in liquid solution[2], have been functionalized both with 2-naphthalenethiol and alkanethiol having different length. In addition to bulk heterojunction structures with optimized interpenetrating network of donors and acceptor domains, we have chosen to study planar heterojunctions (PHJs), consisting of three component thin films realized by sequential deposition of P3HT, AuNPs and PCBM from orthogonal solvents.

Insight into the primary mode of action of TiO2 nanoparticles on Escherichia coli in the dark.

2015

16 pages; International audience; Large-scale production and incorporation of titanium dioxide nanoparticles (NP-TiO2 ) in consumer products leads to their potential release into the environment and raises the question of their toxicity. The bactericidal mechanism of NP-TiO2 under UV light is known to involve oxidative stress due to the generation of reactive oxygen species. In the dark, several studies revealed that NP-TiO2 can exert toxicological effects. However, the mode of action of these nanoparticles is still controversial. In the present study, we used a combination of fluorescent probes to show that NP-TiO2 causes Escherichia coli membrane depolarization and loss of integrity, lead…

Selective and sensitive colorimetric detection of the neurotransmitter serotonin based on the aggregation of bifunctionalised gold nanoparticles

2018

[EN] We report a simple, sensitive and selective method for the colorimetric detection of serotonin (5-HT) in aqueous media using bifunctionalized gold nanoparticles (AuNPs). The probe (1) consisted of AuNPs functionalised with dithiobis(succinimidylpropionate) (DSP) and N-acetyl-l-cysteine (NALC). DSP was chosen to react with the amino group of 5-HT, whereas NALC was chosen to bind the hydroxyl group in 5-HT through hydrogen bonding and electrostatic interactions. A double interaction between nanoparticles and the hydroxyl and the amino group of serotonin led to interparticle-crosslinking aggregation. This, resulted in a colour change from red to blue that can be observed by the naked eye.…

Colorimetric detection of normetanephrine, a pheochromocytoma biomarker, using bifunctionalised gold nanoparticles.

2019

[EN] A simple and effective colorimetric method for the detection of normetanephrine (NMN), an O-methylated metabolite of norepinephrine, using functionalised gold nanoparticles is described. This metabolite is an important biomarker in the diagnosis of adrenal tumours such as pheocromocytoma or paraganglioma. The colorimetric probe consists of spherical gold nanoparticles (AuNPs) functionalised with two different ligands, which specifically recognize different functional groups in normetanephrine. Thus, a benzaldehyde-terminated ligand was used for the recognition of the amino alcohol moiety in NMN, by forming the corresponding oxazolidine. On the other hand, N-acetyl-cysteine was chosen f…

STRATEGIE DI DIREZIONAMENTO ALL’EPATOCARCINOMA DI FARMACI ANTITUMORALI MEDIANTE SISTEMI NANOPARTICELLARI E DI VISUALIZZAZIONE IN CELLULE TUMORALI DEL…

Lo scopo di questo lavoro di tesi è stato quello di realizzare nuovi sistemi nanoparticellari per il direzionamento di farmaci o di agenti per l’imaging, potenzialmente utilizzabili per la terapia e/o per la diagnosi dell’epatocarcinoma (HCC), in particolare per quelle forme caratterizzate dall’overespressione del recettore di membrana degli epatociti ASGP-R o del recettore mitocondriale TSPO. In particolare, nel capitolo 2 sono state descritte la sintesi, la caratterizzazione chimico fisica, la capacità di internalizzazione cellulare e l’efficacia antitumorale di un nuovo sistema nanoparticellare, costituito da un dendrimero a struttura poli-amido-aminica (PAMAM) di quarta generazione, opp…

Experimental quantification of useful and parasitic absorption of light in plasmon-enhanced thin silicon films for solar cells application

2016

AbstractA combination of photocurrent and photothermal spectroscopic techniques is applied to experimentally quantify the useful and parasitic absorption of light in thin hydrogenated microcrystalline silicon (μc-Si:H) films incorporating optimized metal nanoparticle arrays, located at the rear surface, for improved light trapping via resonant plasmonic scattering. The photothermal technique accounts for the total absorptance and the photocurrent signal accounts only for the photons absorbed in the μc-Si:H layer (useful absorptance); therefore, the method allows for independent quantification of the useful and parasitic absorptance of the plasmonic (or any other) light trapping structure. W…

Formation and evolution of self-organized Au nanorings on indium-tin-oxide surface

2011

This work reports on the formation of Au nanoclusters and on their evolution in nanoring structures on indium-tin-oxide surface by sputtering deposition and annealing processes. The quantification of the characteristics of the nanorings (surface density, depth, height, and width) is performed by atomic force microscopy. The possibility to control these characteristics by tuning annealing temperature and time is demonstrated establishing relations which allow to set the process parameters to obtain nanostructures of desired morphological properties for various technological applications. © 2011 American Institute of Physics.