Chemical Modification of Graphene Oxide through Diazonium Chemistry and Its Influence on the Structure-Property Relationships of Graphene Oxide-Iron Oxide Nanocomposites.

4-Carboxyphenyl groups are covalently grafted onto graphene oxide via diazonium chemistry for studying their role on the adsorption of iron oxide nanoparticles. The nanoparticles are deposited via a novel phase-transfer approach involving specific interactions at the interface between two immiscible solvents. The increased density and the homogeneous distribution of surface carboxyl moieties enable the preparation of a nanocomposite with improved iron oxide distribution and loading. Structure-properties relationships are investigated by analysing the electrochemical properties of the nanocomposites, which are regarded as promising active materials for application in supercapacitors. It is demonstrated that the nature of the interactions between the components similarly affects the overall electrochemical performances of the nanocomposites and the structure of the materials.

In-vacuum projection of nanoparticles for on-chip tunneling spectroscopy.

Starting with a discussion of the percolation problem applied to the trapping of conducting nanoparticles between nanometer-spaced electrodes, we show that a good strategy to trap a single nanoparticle between the electrodes is to prepare chips with low coverage of nanoparticles to avoid percolating current paths. To increase the probability of trapping a single nanoparticle, we developed a new method where nanoparticles are projected in-vacuum on the chip, followed by a measure of the tunnel current, in a cycle that is repeated up to a few thousand times until a preset threshold value is reached. A plot of the tunneling current as a function of time allows discriminating between the two possible current paths, i.e., a single nanoparticle trapped between the electrodes or a percolating path across many nanoparticles. We applied the method to prepare chip circuits with single gold nanoparticles, as demonstrated by the observation of Coulomb blockade. Furthermore, we applied the method to trap single magnetite nanoparticles for the study of electric-field-induced switching from insulator to metal in single nanoparticles.

Zirconia-doped nanoparticles: organic coating, polymeric entrapment and application as dual-imaging agents.

Zirconia nanoparticles doped with Eu3+, Tb3+ and Gd3+ ions have been synthesized following the benzyl alcohol route. The nanoparticles were coated with N-hydroxydodecanamide and encapsulated in PLGA-b-PEG-COOH nanomicelles. The magnetic and fluorescent properties of these hybrid nanocarriers were investigated, proving them to be potential dual-imaging contrast agents.

One-step synthesis and self-assembly of metal oxide nanoparticles into 3D superlattices.

A simple one-pot approach based on the "benzyl alcohol route" is introduced for the fabrication of highly ordered supercrystals composed of highly uniform 3-4 nm zirconia and rare-earth stabilized zirconia nanoparticles. The as-fabricated supercrystals reach sizes larger than 10 µm and present well-defined 3D morphologies such as flower-like, rhombic dodecahedron, and bipyramids. This system is unique in that the supercrystals are formed in one-step directly in the reaction medium where the nanoparticles are synthesized. The uniformity in nanocrystal shape and size is attributed to the in situ formation of benzoate species that directs the nanoparticle growth and assembly. The low colloidal stabilization of the benzoate-capped nanoparticles in benzyl alcohol promotes the formation of supercrystals in solution by π-π interaction between the in situ formed benzoate ligands attached to neighboring particles. By varying the reaction temperature and the nature of the doping the way the nanobulding blocks assemble in the supercrystals could be controlled. Standard FCC superlattice packings were found together with more unusual ones with P6/mmm and R ̅3m symmetries.

Design, synthesis and biological evaluation of pyrazole derivatives as potential multi-kinase inhibitors in hepatocellular carcinoma.

We described the optimization, by molecular modelling, of small pyrazole derivatives, as kinase inhibitors, obtained through a 1,3-dipolar cycloaddition between nitrile imines and functionalized acetylenes. The two compounds, selected as potential agents active against hepatocellular carcinoma (HCC) were then evaluated in vitro for their biological activity on HCC-derived cell lines. The compounds show a promising inhibitory growth efficacy (IC(50) 50-100 µM) in SNU449 cell line, as well as block of cell cycle progression and induction of apoptosis, and can be considered as lead compounds for further SAR developments.