Search results for " Gold"
showing 10 items of 278 documents
Mapping the plasmonic response of gold nanoparticles embedded in TiO2thin films
2015
We present the mapping of the plasmonic properties of gold nanoparticles that are embedded in a TiO2 thin film deposited over two different substrates, glass and silicon. An improved electron energy-loss spectroscopy (EELS) imaging technique was used to extract plasmon maps with nanometre resolution. Several representative cases of randomly dispersed NPs have been examined to carefully evaluate surrounding effects on the optical response of such nanostructured material. Data were compared to analytical calculations and showed good agreement. These results validate previous structural and far-field optical results and provide a clear description of the optical phenomena that take place at a …
The Important Role of the Nuclearity, Rigidity, and Solubility of Phosphane Ligands in the Biological Activity of Gold(I) Complexes
2018
A series of 4-ethynylaniline gold(I) complexes containing monophosphane (1,3,5-triaza-7-phosphaadamantane (pta; 2), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (3), and PR3 , with R=naphthyl (4), phenyl (5), and ethyl (6)) and diphosphane (bis(diphenylphosphino)acetylene (dppa; 7), trans-1,2-bis(diphenylphosphino)ethene (dppet; 8), 1,2-bis(diphenylphosphino)ethane (dppe; 9), and 1,3-bis(diphenylphosphino)propane (dppp; 10)) ligands have been synthesized and their efficiency against tumor cells evaluated. The cytotoxicity of complexes 2-10 was evaluated in human colorectal (HCT116) and ovarian (A2780) carcinoma as well as in normal human fibroblasts. All the complexes showed a hi…
Electrochemistry of methylene blue at an alkanethiol modified electrode
2012
International audience; Gold surfaces were derivatized with decanethiol. The electrochemistry of methylene blue at these modified electrodes was investigated in function of the gold cleaning process and compared with the results obtained at a bare gold electrode. Cyclic voltammetry at low methylene blue concentrations (c(MB) <= 16 mu M) yielded surface behavior data. The properties of the film vary with the electrode pretreatment. Without electrochemical cleaning step, the standard potential at a gold electrode modified with 1-decanethiol is nearly the same as on a bare gold electrode. On the other hand, when the electrode is electrochemically cleaned before adsorption of the alkanethiols, …
Glycopeptide-functionalized gold nanoparticles for antibody induction against the tumor associated mucin-1 glycoprotein
2015
We report the preparation of gold nanoparticle (AuNP)-based vaccine candidates against the tumor-associated form of the mucin-1 (MUC1) glycoprotein. Chimeric peptides, consisting of a glycopeptide sequence derived from MUC1 and the T-cell epitope P30 sequence were immobilized on PEGylated AuNPs and the ability to induce selective antibodies in vivo was investigated. After immunization, mice showed significant MHC-II mediated immune responses and their antisera recognized human MCF-7 breast cancer cells. Nanoparticles designed according to this report may become key players in the development of anticancer vaccines.
Johann Sebastian Bach - Variazioni Goldberg BWV 988
2017
Il saggio descrive la genesi e la struttura compositiva delle "Variazioni Goldberg" (1741) di Johann Sebastian Bach, anche in rapporto con alcune fra le ultime opere del "Periodo di Lipsia".
Application of an interspecific competition model to predict the growth of Aeromonas hydrophyla on fish surfaces during refrigerated storage (Anwendu…
2007
The growth of Aeromonas hydrophila and the aerobic mesophilic plate count (APC) on gilthead seabream surfaces was evaluated during refrigerated storage (21 days). The related growth curves were compared with those obtained by a conventional third order predictive model obtaining a low agreement between observed and predicted data (Root Mean Squared Error = 1.77 for Aeromonas hydrophila and 0.64 for APC).The Lotka-Volterra interspecific competition model was used in order to calculate the degree of interaction between the two bacterial populations (beta_{Ah/APC} and beta_{APC/Ah}, respectively, the interspecific competition coefficients of APC on Aeromonas hydrophila and vice-versa). Afterwa…
Gold Nanoparticles Coated with a Thermosensitive Hyperbranched Polyelectrolyte: Towards Smart Temperature and pH Nanosensors
2008
In syringe hybrid monoliths modified with gold nanoparticles for selective extraction of glutathione in biological fluids prior to its determination …
2020
Abstract In this work, a simple device for extraction glutathione (GSH) in biological fluids using a hybrid monolithic material within a polypropylene syringe is developed. For this purpose, glycidyl methacrylate-based monolith was firstly prepared within this housing material, and the polymer was modified with different ligands (ammonia, cysteamine and cystamine). The resulting materials (containing amine or thiol groups, respectively) were then functionalized with gold nanoparticles (AuNPs). The hybrid material that gave the largest AuNPs coverage was selected as solid-phase (SPE) sorbent and several variables affecting the extraction recovery of this compound were investigated. Under opt…
Supramolecular functionalization and concomitant enhancement in properties of Au25 clusters
2014
We present a versatile approach for tuning the surface functionality of an atomically precise 25 atom gold cluster using specific host-guest interactions between ?-cyclodextrin (CD) and the ligand anchored on the cluster. The supramolecular interaction between the Au25 cluster protected by 4-(t-butyl)benzyl mercaptan, labeled Au25SBB18, and CD yielding Au25SBB18�?�CDn (n = 1, 2, 3, and 4) has been probed experimentally using various spectroscopic techniques and was further analyzed by density functional theory calculations and molecular modeling. The viability of our method in modifying the properties of differently functionalized Au25 clusters is demonstrated. Besides modifying their optoe…
Exploiting multivalent nanoparticles for the supramolecular functionalization of graphene with a nonplanar recognition motif.
2013
The supramolecular modification of planar graphene with the geometri- cally mismatched, curved 9,10-di(1,3-dithiole-2-ylidene)-9,10-dihydroanthracene (exTTF) molecule is demonstrated. The exTTF-graphene interaction is governed by p-p and CH-p interactions, with a negligible contribution from charge transfer. We amplified these weak forces through multivalent gold nanoparticles. Our re- sults show that planarity is not a prerequisite for recognition motifs for graphene.