Enhanced Sensory Properties of a Multichannel Quartz Crystal Microbalance Coated with Polymeric Nanobeads.

In this study the sensorial performances of a four-channel quartz crystalmicrobalance implemented on a single quartz plate are reported and compared with those offour independent quartz crystal microbalances. Particular attention has been devoted to bothcross talk in responses and sensor sensitivity. A recently synthesized nanostructuredpolymer, poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)], has been used aschemical interactive material. The interactions of our sensor system with relative humidityare also reported. The multichannel device shows a better homogeneity of the masssensitivity with a spread of the values less then 4% compared to a 50% spread observed inthe set of four microbalances.

Epigenetic effects of chromatin remodeling agents on organotypic cultures.

BACKGROUND: Tumor epigenetic defects are of increasing relevance to clinical practice, because they are 'druggable' targets for cancer therapy using chromatin-remodeling agents (CRAs). New evidences highlight the importance of the microenvironment on the epigenome regulation and the need to use culture models able to preserve tissue morphology, to better understand the action of CRAs. Methods & methods: We studied the epigenetic response induced by culturing and CRAs in a preclinical model, preserving ex vivo the original tissue microenvironment and morphology, assessing different epigenetic signatures. Our overall findings suggest that culturing and CRAs cause heterogeneous effects on the genes methylation; CRAs affect the global DNA methylation and can trigger an active DNA demethylation; the culture induces alterations in the histone deacetylase expression. CONCLUSION: Despite the limited number of cases, these findings can be considered a proof of concept of the possibility to test CRAs epigenetic effects on ex vivo tissues maintained in their native tissue architecture.

Platinum nanoparticles on electrospun titania nanofibers as hydrogen sensing materials working at room temperature.

Platinum nanoparticles (PtNPs), with diameters of 3-10 nm, were synthesized by water phase reduction, using 3-mercapto-1-propanesulfonate (3MPS) as a hydrophilic capping agent. PtNPs were deposited by a dipcoating technique on titania nanofibers (TiO2NFs), obtained by electrospinning. The investigated properties of the Pt-TiO2 hybrid at room temperature show that this material combines the properties of photoconduction of titania and the photocatalytic activity of the hybrid. To assess the best performance of Pt-TiO2, different measurements were performed at room temperature, comparing hydrogen response under UV of the uncoated TiO2NFs, compared with the Pt-TiO2 system prepared with two different amounts of PtNPs. During the sensing tests toward hydrogen an enhancement of photoconductivity (150%), an increase in response (400%) and an overall improvement of their dynamic behaviour were observed.

From nanospheres to microribbons: Self-assembled Eosin Y doped PMMA nanoparticles as photonic crystals.

A modified emulsion synthesis of poly(methylmethacrylate) (PMMA) with the Eosin Y (EY), commercial chromophore, yields dye doped polymeric nanoparticles (PMMA@EY). A systematic investigation on the experimental parameters (monomer and initiator concentration, reaction time and MMA/EY molar ratio) has been explored to modulate physico-chemical properties of the dye doped polymeric colloids. Spherical shaped particles, doped with EY (0.5-3.0 wt%; loading efficiency η = 11-15%), with controlled diameters in the range 240-510 nm, low dispersity and ζ-potential values in the range between -42 mV and -59 mV, have been synthesized and characterized by means of UV-Vis spectrometry, Dynamic Light Scattering (DLS), laser Doppler electrophoresis and Scanning Electron Microscopy (SEM). Microribbons based on PMMA@EY nanoparticles have been fabricated by room temperature self-assembly of aqueous colloidal suspension on highly wettable glass substrates. Surface chemical treatment assisted the formation of long (up to few centimeters) regular ribbons with rectangular section. Lateral size and height of the structures have been controlled by changing the suspension concentration and/or the deposition volume: the higher suspension concentration produces larger and thicker ribbons and the higher deposited volume produces thicker ribbons (up to 23 µm with 198 µL of a 3 wt% suspension). Moreover, a transition from a film-like to a ribbon-like growth has been observed with increasing nanoparticles concentration. Short range ordering and photonic crystal features have been maintained in the fluorescent ribbon microarchitecture, resulting in a self-assembled material with excellent potential for the development of mirror-less and random lasers.

Functional polymeric nanoparticles for dexamethasone loading and release.

Poly(phenylacetylene) (PPA) and poly(phenylacetylene-co-acrylic acid) (P(PA-co-AA)), nanoparticles bioconjugated with dexamethasone (DXM) during the synthesis, named PPA@DXM and P(PA-co-AA)@DXM, were prepared by a modified surfactant free emulsion method. The loading was studied as a function of different functionality grades of the copolymer and different amounts of drug, obtaining up to 90% of drug loading for P(PA-co-AA)@DXM with 8/1 PA/AA monomer ratio. The SEM images and DLS measurements showed spheres with average diameters in the range 190-500 nm, depending on the content of acrylic acid monomer units in the copolymer and of DXM loading. ζ-potential and surface charge density of DXM loaded nanoparticles were also investigated and confirm the charge density modulation in the range 0.62-2.68σ (µC/m(2)). The results highlight the enhanced capability of our copolymer of hosting DXM, with the advantage of a control of size, surface functionality, charge and release. Moreover we demonstrate for the first time the ability of P(PA-co-AA) DXM loaded nanoparticles to be used in the apoptosis inhibition of human tumor cells (HeLa). On the basis of the results obtained by comparing the effects elicited in HeLa cells by free DXM versus DXM loaded nanoparticles we confirmed the biological efficacy of our preparation.

Osmosis based method drives the self-assembly of polymeric chains into micro- and nanostructures.

Polymers derived from monomers with a variety of functionalities provide materials with a vast range of properties and applications. Worldwide research has recently developed a wide number of methods suitable for the preparation of polymeric materials of nanometric dimensions, in view of the fact that, at the nanoscale level, new and unexpected properties emerge and lead to innovative applications. In this framework, we have exploited an easy method for the generation of nanostructures, regardless of the chemical structure of the pristine amorphous polymers, that is, biopolymers (e.g., polysaccharides) and synthetic, functional, and structural polymers (i.e, polystyrene, polymethylmethacrylates, polyacetylenes, and polymetallaynes). The nanostructure of these macromolecules, considered as the prototypes of various classes of polymeric materials, was achieved by using a simple and versatile procedure based on an osmotic method (OBM). Depending on the choice of solvent/nonsolvent pairs, the dialysis membrane molecular weight cutoff (MWCO), temperature, and polymer concentration, different morphologies can be obtained (e.g., spheres, sponges, disks, and fibers); also, a tuning of the nanoparticle dimensions ranging from the micro- to nanoscale has been obtained.