Search results for "Nanoparticles"
showing 10 items of 1286 documents
Synthesis, physico-chemical and biological study of trialkylsiloxyalkyl amine coated iron oxide/oleic acid magnetic nanoparticles for the treatment o…
2008
New original water-soluble magnetic nanoparticles based on natural components, magnetite–oleic acid–biologically active silyl modified alkanolamine, were synthesized. Physico-chemical characterization, i.e. magnetic properties, concentration of magnetite, size of iron oxide core, of the nanoparticles synthesized and the corresponding magnetic fluids obtained, was carried out. Magnetic fluids were screened for in vitro cytotoxicity concerning human fibrosarcoma (HT-1080), mouse hepatoma (MG-22A) monolayer tumour cell lines and normal mouse fibroblasts (NIH 3T3). They possess low or moderate cytotoxic effects, are non-toxic, exhibit high NO-induction ability and strongly change tumour cell mo…
Myoglobin on Silica: A Case Study of the Impact of Adsorption on Protein Structure and Dynamics
2013
International audience; If protein structure and function changes upon adsorption are well documented, modification of adsorbed protein dynamics remains a blind spot, despite its importance in biological processes. The adsorption of metmyoglobin on a silica surface was studied by isotherm measurements, microcalorimetry, circular dichroïsm, and UV-visible spectroscopy to determine the thermodynamic parameters of protein adsorption and consequent structure modifications. The mean square displacement and the vibrational densities of states of the adsorbed protein were measured by elastic and inelastic neutron scattering experiments. A decrease of protein flexibility and depletion in low freque…
Analysis of Localized Surface Plasmon Resonances in Spherical Jellium Clusters and Their Assemblies
2017
Due to multiple possible applications of physico-chemical properties of plasmonic metal nanoparticles and particle systems, there is high interest to understand the mechanisms that underlie the birth of localized surface plasmon resonance (LSPR). Here we studied the birth of the LSPR in spherical jellium clusters with the density of sodium and with 8, 20, 34, 40, 58, 92, 138, and 186 electrons, by using the linear response time-dependent density functional theory (lr-TDDFT). The coupling of the individual plasmon resonances in dimer, trimer, tetramer, and hexamer cluster assemblies consisting of the 8-electron cluster was also studied. The Kohn-Sham electron-hole transitions contributing to…
A physiologically active interpenetrating collagen network that supports growth and migration of epidermal keratinocytes: zinc-polyP nanoparticles in…
2020
The distinguished property of the physiological polymer, inorganic polyphosphate (polyP), is to act as a bio-intelligent material which releases stimulus-dependent metabolic energy to accelerate wound healing. This characteristic is based on the bio-imitating feature of polyP to be converted, upon exposure to peptide-containing body fluids, from stable amorphous nanoparticles to a physiologically active and energy-delivering coacervate phase. This property of polyP has been utilized to fabricate a wound mat consisting of compressed collagen supplemented with amorphous polyP particles, formed from the inorganic polyanion with an over-stoichiometric ratio of zinc ions. The proliferation and t…
Biomimetic Alginate/Gelatin Cross-Linked Hydrogels Supplemented with Polyphosphate for Wound Healing Applications
2020
In the present study, the fabrication of a biomimetic wound dressing that mimics the extracellular matrix, consisting of a hydrogel matrix composed of non-oxidized and periodate-oxidized marine alginate, was prepared to which gelatin was bound via Schiff base formation. Into this alginate/oxidized-alginate-gelatin hydrogel, polyP was stably but reversibly integrated by ionic cross-linking with Zn2+ ions. Thereby, a soft hybrid material is obtained, consisting of a more rigid alginate scaffold and porous structures formed by the oxidized-alginate-gelatin hydrogel with ionically cross-linked polyP. Two forms of the Zn-polyP-containing matrices were obtained based on the property of polyP to f…
Small-sized platinum nanoparticles in soil organic matter: Influence on water holding capacity, evaporation and structural rigidity
2019
Abstract Engineered and anthropogenic nanoparticles represent a new type of pollutants. Up until now, many studies have reported its adverse effect on biota, but the potential influence on the properties and functions of environmental compartments has largely been ignored. In this work, the effect of Pt nanoparticles on the functions and properties of model soil organic matter has been studied. Using differential scanning calorimetry and molecular modeling, the effect of a wide range of 3 nm Pt nanoparticles concentrations on water holding capacity, the strength of water binding, the stability of water molecule bridges and the content of aliphatic crystallites was studied. It was found that…
Measuring the differential scattering cross-section of gold nanoparticles - art. no. 70321E
2008
International audience; In this paper we present an experimental apparatus capable of measuring the differential scattering cross sections of individual nanoparticles and arrangement of nanoparticles. We show that the mapping a partial differential scattering cross section, qualitative information about the electromagnetic local density of states dominated by evanescent modes scattered by the structure can be obtained.
Development of iron oxide/activated carbon nanoparticle composite for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution
2018
Iron oxide (Fe3O4) and iron oxide/activated carbon (Fe3O4/AC) were fabricated by co-precipitation method for the removal of Cr(VI), Cu(II) and Cd(II) ions from aqueous solution in batch mode. These nanoparticles were characterized by BET, FTIR, XRD, SEM/TEM and VSM. The optimum conditions for the removal of ions were pH = 2 for Cr(VI) and 6 for Cu(II) and Cd(II), initial metal ion concentration = 50 mg L−1, nanoparticle dose = 50 mg/10 mL, temperature = 25 ± 1 °C, shaking speed = 180 rpm and contact time = 3 h. The equilibrium data of ions sorption were well described by Langmuir, Freundlich, Redlich-Peterson and Intraparticle Diffusion model. The R2 values obtained by Langmuir model were h…
Polysulfonate Cappings on Upconversion Nanoparticles Prevent Their Disintegration in Water and Provide Superior Stability in a Highly Acidic Medium
2018
The stability of organic cappings on hexagonal NaYF4:Ln3+ upconversion nanoparticles (UCNPs) is crucial for their luminescence efficiency in aqueous solutions. The capping removal quickens as the acidity of the medium increases. We demonstrate here that polysulfonates, namely poly(2-acrylamido-2-methyl-1-propanesulfonate) (PAMPS) and poly(sodium 4-styrene sulfonate) (PSS), remain anchored to the surface of NaYF4:Yb3+,Er3+/Tm3 UCNPs even at a pH as low as 2 due to strong acidity of the sulfonate anchoring groups (pKa of ca. −3). Bare UCNPs progressively disintegrate into their compositional F–, Na+, Y3+, and Ln3+ ions. Their disintegration is particularly worrying in highly diluted dispersio…
Lanthanide complexes as imaging agents anchored on nano-sized particles of boehmite
2011
International audience; The synthesis of boehmite nanoparticles modified with lanthanides (Eu, Tb and Gd) is described. Their synthesis, characterization and in vitro assays with HeLa cells were performed. The nuclear magnetic relaxation dispersion (NMRD) profiles of the two chelating moieties were studied. Imaging data from laser scanning confocal fluorescence microscopy and flow cytometry revealed that the nanoscaffolds were taken up by the cells, distributed throughout the cytoplasm and showed no toxicity. This platform could represent an alternative to silica-based inert matrices as imaging vehicles.