Organic and inorganic nanoparticles for imaging and sensing in water

Nanotechnology aims at the design, synthesis, characterization and application of materials and devices on the nanoscale. Nanoparticles are defined as materials with the three dimensions in the space less than 100 nm. They possess properties hugely different from the corresponding macroscopic materials. Their peculiarities depend on the reduced size, shape, composition and interface, all aspects that can be controlled during the synthesis. Moreover, nanoparticles can act as platforms for assemble well-defined multifunctional structures able to perform varied tasks. Nanoparticles can be made by inorganic materials and by soft materials. In the currently work a wide range of nanoparticles have been designed, synthesized and characterized for various purposes. In chapter 4 we propose simple and cheap strategy to develop multi-stimuli sensitive perylene diimide (PDI) molecules to create new smart materials by self-assembly. In chapter 5 we report synthesis of designed molecule that self-assemble in nanoparticles in biocompatible environment without any dramatic decrease of fluorescence brightness. In chapter 6 a similar work has been repeated with commercial fluorophores. Detection of chemical and biological agents plays a fundamental role in environmental and biomedical sciences. In chapter 7 small gold nanocluster functionalised with seven thiols in has been studied in presence active pharmaceutical ingredient (API). In chapter eight we try to increase melanin radiation protection activity both increasing number of stable free radicals and introducing oxidative ion transition metal. We have chosen Fe(III) and Mn(III) to increase oxidative ability and Zn(II), that do not possess oxidative ability as reference. We used 4-amino-TEMPO to increase number of stable free radicals

Self-Assembled Biocompatible Fluorescent Nanoparticles for Bioimaging

Fluorescence is a powerful tool for mapping biological events in real-time with high spatial resolution. Ultra-bright probes are needed in order to achieve high sensitivity: these probes are typically obtained by gathering a huge number of fluorophores in a single nanoparticle (NP). Unfortunately this assembly produces quenching of the fluorescence because of short-range intermolecular interactions. Here we demonstrate that rational structural modification of a well-known molecular fluorophore N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) (NBD) produces fluorophores that self-assemble in nanoparticles in the biocompatible environment without any dramatic decrease of the fluorescence quantum yield. Most importantly, the resulting NP show, in an aqueous environment, a brightness which is more than six orders of magnitude higher than the molecular component in the organic solvent. Moreover, the NP are prepared by nanoprecipitation and they are stabilized only via non-covalent interaction, they are surprisingly stable and can be observed as individual bright spots freely diffusing in solution at a concentration as low as 1 nM. The suitability of the NP as biocompatible fluorescent probes was demonstrated in the case of HeLa cells by fluorescence confocal microscopy and MTS assays

Synthesis and characterization of CdS nanoparticles embedded in a polymethylmethacrylate matrix

CdS nanopowder capped with sodium bis(2-ethylhexyl)sulfosuccinate was synthesized by using water-in-oil microemulsions. The CdS nanoparticles of about 5 nm obtained were embedded in polymethylmethacrylate matrix by a photocuring process. The transparent yellow solid compound was characterized by optical absorption and emission spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The properties of this compound were compared with those of the nanopowder dispersed in heptane and in methylmethacrylate. The results obtained indicate that the nanoparticles are homogeneously dispersed in the matrix and do not change in size during the embedding process. Even if the surface slightly changes its luminescence properties, as a consequence of the different new chemical environment, the final product seems to be suitable for practical applications

On regulated solutions of impulsive differential equations with variable times

In this paper we investigate the unified theory for solutions of differential equations without impulses and with impulses, even at variable times, allowing the presence of beating phenomena, in the space of regulated functions. One of the aim of the paper is to give sufficient conditions to ensure that a regulated solution of an impulsive problem is globally defined

Towards Ultra-Bright Gold Nanoclusters

Fluorescence bioimaging is a non-invasive technique that permits to investigate living organism in real time with high tridimensional resolution. Properly engineered fluorescent (or photoluminescent) nanoparticles promise to surpass conventional fluorescent molecular probes as contrast agent. Photoluminescent semiconductor quantum dots show, for example, enhanced brightness and photostability. Concerns arising from the toxic metal content of quantum dots prompted the search for alternative inorganic nanoparticles with similar properties but less hazardous. Gold is almost unanimously considered to be highly tolerated by living organism and the environment. Nevertheless, although photoluminescence of gold nanocluster is known by decades, brightness of these nanoparticles has typically reported to be low, mostly because of the poor photoluminescence quantum yield (< 1 %). Different approaches have been proposed to enhance this poor quantum yield aiming to achieve ultra-bright gold nanoparticles with features superior to conventional dyes. Here most relevant and recent results in this direction are summarized and critically discussed

A Selective Ratiometric Fluorescent Probe for No-Wash Detection of PVC Microplastic

Microplastics (MP) are micrometric plastic particles present in drinking water, food and the environment that constitute an emerging pollutant and pose a menace to human health. Novel methods for the fast detection of these new contaminants are needed. Fluorescence-based detection exploits the use of specific probes to label the MP particles. This method can be environmentally friendly, low-cost, easily scalable but also very sensitive and specific. Here, we present the synthesis and application of a new probe based on perylene-diimide (PDI), which can be prepared in a few minutes by a one-pot reaction using a conventional microwave oven and can be used for the direct detection of MP in water without any further treatment of the sample. The green fluorescence is strongly quenched in water at neutral pH because of the formation dimers. The ability of the probe to label MP was tested for polyvinyl chloride (PVC), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), poly methyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE). The probe showed considerable selectivity to PVC MP, which presented an intense red emission after staining. Interestingly, the fluorescence of the MP after labeling could be detected, under excitation with a blue diode, with a conventional CMOS color camera. Good selectivity was achieved analyzing the red to green fluorescence intensity ratio. UV–Vis absorption, steady-state and time-resolved fluorescence spectroscopy, fluorescence anisotropy, fluorescence wide-field and confocal laser scanning microscopy allowed elucidating the mechanism of the staining in detail

A national survey on prevalence of possible echocardiographic red flags of amyloid cardiomyopathy in consecutive patients undergoing routine echocardiography: study design and patients characterization-the first insight from the AC-TIVE Study

none46National survey on prevalence of possible echocardiographic red flags of amyloid cardiomyopathy in consecutive patients undergoing routine echocardiography: study design and patients characterization-the first insight from the AC-TIVE StudynoneMarco Merlo, Aldostefano Porcari, Linda Pagura, Matteo Cameli, Giuseppe Vergaro, Beatrice Musumeci, Elena Biagini, Marco Canepa, Lia Crotti, Massimo Imazio, Cinzia Forleo, Francesco Cappelli, Stefano Favale, Gianluca Di Bella, Franca Dore, Carlo Mario Lombardi, Rita Pavasini, Valeria Rella, Giuseppe Palmiero, Martina Caiazza, Miriam Albanese, Andrea Igoren Guaricci, Giovanna Branzi, Angelo Giuseppe Caponetti, Giulia Saturi, Giovanni La Malfa, Andrea Carlo Merlo, Alessandro Andreis, Francesco Bruno, Francesca Longo, Enrico Sfriso, Luca Di Ienno, Giuseppe De Carli, Elisa Giacomin, Valentina Spini, Antonino Milidoni, Giuseppe Limongelli, Camillo Autore, Iacopo Olivotto, Luigi Badano, Gianfranco Parati, Stefano Perlini, Marco Metra, Michele Emdin, Claudio Rapezzi, Gianfranco SinagraMerlo, Marco; Porcari, Aldostefano; Pagura, Linda; Cameli, Matteo; Vergaro, Giuseppe; Musumeci, Beatrice; Biagini, Elena; Canepa, Marco; Crotti, Lia; Imazio, Massimo; Forleo, Cinzia; Cappelli, Francesco; Favale, Stefano; Di Bella, Gianluca; Dore, Franca; Mario Lombardi, Carlo; Pavasini, Rita; Rella, Valeria; Palmiero, Giuseppe; Caiazza, Martina; Albanese, Miriam; Igoren Guaricci, Andrea; Branzi, Giovanna; Giuseppe Caponetti, Angelo; Saturi, Giulia; La Malfa, Giovanni; Carlo Merlo, Andrea; Andreis, Alessandro; Bruno, Francesco; Longo, Francesca; Sfriso, Enrico; Di Ienno, Luca; De Carli, Giuseppe; Giacomin, Elisa; Spini, Valentina; Milidoni, Antonino; Limongelli, Giuseppe; Autore, Camillo; Olivotto, Iacopo; Badano, Luigi; Parati, Gianfranco; Perlini, Stefano; Metra, Marco; Emdin, Michele; Rapezzi, Claudio; Sinagra, Gianfranc