When dispersed in biological fluids, engineered nanoparticles are selectively coated with proteins, resulting in the formation of a protein corona. It is suggested that the protein corona is critical in regulating the conditions of entry into the cytoplasm of living cells. Recent reports describe this phenomenon as ubiquitous and independent of the nature of the particle. For nanomedicine applications, however, there is a need to design advanced and cost-effective coatings that are resistant to protein adsorption and that increase the biodistribution in vivo. In this study, phosphonic acid poly(ethylene glycol) copolymers were synthesized and used to coat iron oxide particles. The copolymer composition was optimized to provide simple and scalable protocols as well as long-term stability in culture media. It is shown that polymers with multiple phosphonic acid functionalities and PEG chains outperform other types of coating, including ligands, polyelectrolytes, and carboxylic acid functionalized PEG. PEGylated particles exhibit moreover exceptional low cellular uptake, of the order of 100 femtograms of iron per cell. The present approach demonstrates that the surface chemistry of engineered particles is a key parameter in the interactions with cells. It also opens up new avenues for the efficient functionalization of inorganic surfaces.

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A terpyridine-functionalized perylene bisimide chromophore (TPBI) has been used as a building block in the stepwise, layer-by-layer fabrication of self-assembled Fe-TPBI multilayers on gold, with the assembled supramolecular chains oriented approximately perpendicular to the gold surface. Time-resolved spectroscopy measurements seem to indicate that the energy absorbed by the multilayer is promptly dissipated to the gold surface by ultrafast processes.

Abstract:In this review, we discuss the basic concepts related to (co-)evaporation and (co)sputtering based fabrication methods and the electrical properties of polymer-metal nanocomposite films. Within the organic-inorganic hybrid nanocomposites research framework, the field related to metal-polymer nanocomposites is attracting much interest. In fact, it is opening pathways for engineering flexible composites that exhibit advantageous electrical, optical, or mechanical properties. The metal-polymer nanocomposites research field is, now, a wide, complex, and important part of the nanotechnology revolution. So, with this review we aim, starting from the discussion of specific cases, to focus our attention on the basic microscopic mechanisms and processes and the general concepts suitable for the interpretation of material properties and structure-property correlations. The review aims, in addition, to provide a comprehensive schematization of the main technological applications currently in development worldwide.

Surface-confined polypyridinebased metal complexes are of importance in several applications such as solar energy conversion, luminescent sensors and molecular electronics [1] . Anchoring of complexes on metal surfaces can be obtained, among others, via an intermediate step involving the preparation of a self-assembled monolayer (SAM) with suitable functional tail groups. The SAM can then be used for binding the metal complex, by a stepwise procedure involving coordination chemistry reactions, directly at the surface. However, the known synthetic routes for bulk preparation of metal complexes, such as polypyridine complexes of ruthenium, osmium and iridium (among the most interesting polypyridine metal complexes, because of their outstanding photophysical and redox properties) [2] are based on reaction conditions that could be incompatible with the properties (e.g. thermal stability) of the monolayer that acts as one of the reactants. Indeed, whereas for example, surface-confined iron or cobalt polypyridine complexes have been prepared by a stepwise procedure based on suitably-derivatized surfaces, [3] analogous ruthenium systems have been elusive up to now, in spite of the large interest of these latter species.Here we report the "proof of concept" that stepwise synthesis of polypyridine-ruthenium complexes by direct coordination reaction at surface is feasible. This is made by means of the reaction between a terpyridine functionalized thiol-based SAM on gold with a suitable precursor of the complex (see Scheme 1). This method allows the preparation of2 + (1; tpy = 2,2':6',2"-terpyridine; MPTP = 4'(4-mercaptophenyl)-2,2':6',2"-terpyridine) directly at the surface of a mixed component SAM of MPTP and mercaptobenzene (MB) (3-surface in Scheme 1). The SAM employed as platform for the reaction is reproducibly obtained with 1:1 MPTP/MB ratio.[4] To the best of our knowledge, this is the first time that preparation of a surface-confined Ru II polypyridine compound by direct coordination of a Ru II precursor to a polypyridine-derivatized gold surface is reported.The surface-anchored ruthenium complex (hereafter called 1-surface) obtained in this way has been studied by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Such investigations involve the comparison of these systems with analogous ones prepared via surface anchoring of the pre-synthesized ruthenium complex 1, whose synthesis is sketched in Scheme 2 and described in the Experimental Section.The stepwise synthesis of 1-surface according to method A (Scheme 1) implies that the terpyridine-based (MB/MPTP) SAM used as reactant should not be damaged under the conditions used for reaction. The usual protocol employed for the synthesis of heteroleptic Ru II terpyridine-type complexes requires relatively severe conditions, since it involves several hours of reaction in refluxing solvent.[5] However, probably due to the relatively weak link of thiolate on gold, the MB/MPTP SAM does not stand long refluxing conditio...

The morphology evolution of nano-grained Ag and Au films deposited on polystyrene (PS) and poly(methyl methacrylate) (PMMA) polymeric layers were studied, using the atomic force microscopy technique, when annealed above the polymers glass transition temperature. The main effects on the morphology changes were identified with those concerning the embedding kinetics of the Ag and Au nanoparticles in the PS or PMMA layers. The embedding process of the nanoparticles follows as a consequence of the long-range mobility of the polymeric chains above the glass transition temperature. In particular, the dependence of the nanoparticles mean height and surface density on the annealing time at various temperatures was quantified. The analyses of these behaviors allowed us: (1) to distinguish the overall embedding process in a first stage in which a thin wetting layer of the polymer coats the nanoparticles followed by a true embedding process of the nanoparticles into the polymer layer; (2) to evaluate the characteristic coating time for the Ag and Au nanoparticles in the PS and PMMA in the first stage; (3) to evaluate the characteristic embedding velocity for the Ag and Au nanoparticles in the PS and PMMA in the second stage; (4) to derive the activation energies for the embedding process of the Ag and Au nanoparticles in PS F. Ruffino ( ) · M.G. Grimaldi

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