Search results for "nanoparticle"

Antioxidant activity of cerium dioxide nanoparticles and nanorods in scavenging hydroxyl radicals

2019

Cerium oxide nanoparticles (CeNPs) have been shown to exhibit antioxidant capabilities, but their efficiency in scavenging reactive oxygen species (ROS) and the underlying mechanisms are not yet well understood. In this study, cerium dioxide nanoparticles (CeNPs) and nanorods (CeNRs) were found to exhibit much stronger scavenging activity than ·OH generation in phosphate buffered saline (PBS) and surrogate lung fluid (SLF). The larger surface area and higher defect density of CeNRs may lead to higher ·OH scavenging activity than for CeNPs. These insights are important to understand the redox activity of cerium nanomaterials and provide clues to the role of CeNPs in biological and environmen…

Tetrazine Click Chemistry for the Modification of 1-Hydroxy-1,1-methylenebisphosphonic Acids: Towards Bio-orthogonal Functionalization of Gold Nanopa…

2016

Inverse electron demand Diels-Alder (iEDDA) was evaluated for the functionalization of gold nanoparticles. The reaction was first modelled with the free coating molecule 1-hydroxy-1,1-methylenebisphosphonate bearing an alkene functionality (HMBPene). A model tetrazine 3,6-dipyridin-2-yl-1,2,4,5-tetrazine (pyTz) was used, kinetic of the reaction was calculated and coupling products were analysed by NMR and HRMS. The reaction was then transposed at the nanoparticle surface. Gold nanoparticles bearing an alkene functionality were obtained using a one-pot methodology with HMBPene and the tetrazine click chemistry was evaluated at their surface using pyTz. The successful coupling was assessed by…

Physico-chemical investigation of nanostructures in liquid phases: Nickel chloride ionic clusters confined in sodium bis(2-ethylhexyl) sulfosuccinate…

2009

The confinement of finite amounts of nickel chloride in the hydrophilic core of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles dispersed in n-heptane has been investigated by FT-IR, UV-vis-NIR and fluorescence spectroscopies. The analysis of experimental data consistently leads to hypothesize that NiCl(2) forms small size ionic clusters stabilized by a monolayer of oriented surfactant molecules. Due to confinement and interfacial effects, these ionic clusters show peculiar photophysical properties, which are different from those possessed by the bulk material. From NiCl(2)/AOT/n-heptane solutions, by evaporation of the organic solvent, interesting salt/surfactant nanocomposi…

Dye loading of amphiphilic poly(organosiloxane) nanoparticles.

2003

Novel patternable and conducting metal-polymer nanocomposites: a step towards advanced mutlifunctional materials

2013

In this work, we present a novel patternable conducting nanocomposite containing gold nanoparticles. Here, the in-situ polymerization of 3T is carried out using HAuCl 4 as oxidizing agent inside PMMA as host matrix. During the bake step, the gold salt is also reduced from Au(III) to Au(0) generating Au nanoparticles in the interpenetrating polymer network (IPN) system. We found that this novel multifunctional resist shows electrical conductivity and plasmonic properties as well as potential patterning capability provided by the host matrix. The resulting nanocomposite has been investigated by TEM and UV-Vis spectroscopy. Electrical characterization was also conducted for different concentra…

Effective pair potential between charged nanoparticles at high volume fractions

2017

Simulations of charged colloidal dispersions are technically challenging. One possible workaround consists in reducing the system to the colloids only, whose interactions are described through an effective pair potential, wf. Still, the determination of wf is difficult mainly because it depends on the colloidal density, ϕ. Here we propose to calculate wf from simulations of a pair of colloids placed in a cubic box with periodic boundary conditions. The variation in ϕ is mimicked by an appropriate change in the concentration of counterions neutralized by an homogeneous background charge. The method is tested at the level of the primitive model. A good description of the structure of the coll…

Quantum dot/cyclodextrin supramolecular systems based on efficient molecular recognition and their use for sensing.

2011

A supramolecular system based on ketoprofen functionalised CdSe/ZnS nanoparticles and pyrene-modified β-CD was prepared and successfully used for molecular sensing of different analytes. In addition, a strategy for the individual recovery of all the components of the sensing assay is reported.

Supramolecular organic-inorganic hybrid assemblies with tunable particle size: interplay of three noncovalent interactions.

2013

Plasmonic optical sensors printed from Ag–PVA nanoinks

2014

In this paper we report on the use of a nanocomposite based on silver nanoparticles embedded in PVA as a plasmonic optical sensor to detect and quantify trace amounts of amines in gas and water, respectively. The transduction mechanism of the sensor is based on the changes of the LSPR band of Ag NPs when analyte molecules are chemisorbed on their surface. The Ag–PVA sensors are fabricated by means of a high-precision microplotter, a direct-write technology developed for printing materials from solution. The nanoink is formulated with a metal precursor (AgNO3) and a polymer (PVA) using an adequate mixture of solvents to meet the rheological requirements for the fluid dispensing process. The …

Quantitative study of the capture of silver nanoparticles by several kinds of soils

2018

The capacity of different soils to capture silver nanoparticles (AgNPs) by measuring changes of an AgNP intrinsic property such as the plasmon for the first time, was studied. In-tube solid-phase microextraction (IT-SPME) coupled on-line to capillary liquid chromatography (CapLC) with diode array detection (DAD) was employed for measuring the interactions between soil and in-contact AgNP dispersions. Its achieved LOD 9 pM assures quantitative retention measurements and selectivity for soil lixiviation was suitable. Electronic microscopy was employed for corroborating the entrapped Ag into the soils. Capture % of AgNPs was calculated in compost (>99%), mountain (>99%), orchard (15±1%) and ur…