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192 results on '"Giorgis, Fabrizio"'

151. SERS active Ag nanoparticles in mesoporous silicon: detection of organic molecules and peptide–antibody assays

Author

Virga, Alessandro, primary, Rivolo, Paola, additional, Descrovi, Emiliano, additional, Chiolerio, Alessandro, additional, Digregorio, Gabriella, additional, Frascella, Francesca, additional, Soster, Marco, additional, Bussolino, Federico, additional, Marchiò, Serena, additional, Geobaldo, Francesco, additional, and Giorgis, Fabrizio, additional

Published
2011
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158. Guided Bloch Surface Waves on Ultrathin Polymeric Ridges

Author

Descrovi, Emiliano, primary, Sfez, Tristan, additional, Quaglio, Marzia, additional, Brunazzo, Daniele, additional, Dominici, Lorenzo, additional, Michelotti, Francesco, additional, Herzig, Hans Peter, additional, Martin, Olivier J. F., additional, and Giorgis, Fabrizio, additional

Published
2010
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162. Amorphous silicon and silicon nitride channel optical waveguides

Author

Celasco, Edvige, primary, Quaglio, Marzia, additional, Chiodoni, Angelica, additional, Ricciardi, Carlo, additional, Pirri, Candido Fabrizio, additional, Dominici, Lorenzo, additional, Michelotti, Francesco, additional, Angelis, Francesco De, additional, Fabrizio, Enzo Di, additional, and Giorgis, Fabrizio, additional

Published
2010
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173. Ultrasensitive Ag-coated TiO2 nanotube arrays for flexible SERS-based optofluidic devices.

Author

Lamberti, Andrea, Virga, Alessandro, Chiadò, Alessandro, Chiodoni, Angelica, Bejtka, Katarzyna, Rivolo, Paola, and Giorgis, Fabrizio

Abstract

In this study, a novel SERS sensor has been developed for repeatable detection of organic molecules and biological assays. Vertically oriented titania nanotube (TiO2 NT) arrays were grown by ultra-fast anodic oxidation of flexible titanium foils and then decorated with Ag nanoparticles (NPs) through d.c. sputtering deposition at room temperature. A parametric study was carried out taking into account the effect of sputtering parameters on the Ag NP arrangements on the NT surface. The structure morphology was investigated by means of scanning and transmission electron microscopy, evidencing the formation of hexagonal close-packed TiO2 NTs coated with Ag nanoparticles showing tunable diameter and distribution. The substrates were employed in a SERS optofluidic device, consisting of a polydimethylsiloxane cover irreversibly sealed to the silver-coated TiO2 NTs, able to detect Rhodamine molecules in ethanol over a wide range of concentrations down to 10−14 M, taking advantage of both electromagnetic and chemical enhancements. In order to evaluate the performances of the SERS substrates in terms of biosensing, an optimized protocol for the immobilization of oligonucleotide probes on the metal-dielectric surfaces was developed for verifying the hybridization events. [ABSTRACT FROM AUTHOR]

Published
2015
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177. Defect Influence on the Electrical Properties of 4H-SiC Schottky Diodes

Author

Scaltrito, Luciano, primary, Celasco, Edvige, additional, Porro, Samuele, additional, Ferrero, Sergio, additional, Giorgis, Fabrizio, additional, Pirri, C. Fabrizio, additional, Perrone, Denis, additional, Meotto, Umberto M., additional, Mandracci, P., additional, Richieri, G., additional, Merlin, Luigi, additional, Cavallini, Anna, additional, Castaldini, Antonio, additional, and Rossi, Marco, additional

Published
2004
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178. Correlation between Defects and Electrical Properties of 4H-SiC Based Schottky Diodes

Author

Scaltrito, Luciano, primary, Porro, Samuele, additional, Giorgis, Fabrizio, additional, Mandracci, P., additional, Cocuzza, M., additional, Pirri, C. Fabrizio, additional, Ricciardi, C., additional, Ferrero, Sergio, additional, Richieri, G., additional, Sgorlon, C., additional, Merlin, Luigi, additional, Cavallini, Anna, additional, and Castaldini, Antonio, additional

Published
2003
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184. Fast optical vapour sensing by Bloch surface waves on porous silicon membranes.

Author

MichelottiF. Michelotti and F. Giorgis are also with Consorzio Nazionale Interuniversitario per le S, Francesco, Sciacca, Beniamino, Dominici, Lorenzo, Quaglio, Marzia, Descrovi, Emiliano, Giorgis, Fabrizio, and Geobaldo, Francesco

Abstract

The coupling of optical Bloch surface waves at the truncated end of one dimensional porous silicon photonic crystals is exploited for fast vapour sensing. Self-standing multilayered membranes bound to transparent substrates were fabricated by electrochemical etching and used in an attenuated total reflection configuration to resonantly excite the surface waves and perform real-time sensing. [ABSTRACT FROM AUTHOR]

Published
2010

186. Optical and photoluminescence properties of a-Si1−xNx: H/a-Si3N4: H and a-Si1−xCx: H/a-SiC: H superlattices

Author

Giorgis, Fabrizio

Abstract

AbstractSuperlattices based on wide-bandgap hydrogenated amorphous silicon based alloys were studied in terms of optical absorption and photo-luminescence properties. A critical comparison between a-Si1−xNx: H/a-Si3N4: H and a-Si1−xCx: H/a-SiC: H multilayers was made, revealing the former as a promising structure for electroluminescent devices in the visible range. As evidence of this potentiality, a light-emitting device was realized using an a-Si1−xNx: H/a-Si3N4: H multilayer as the radiative element.

Published
1997
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188. SERS-active metal-dielectric nanostructures integrated in microfluidic devices for label-free quantitative detection of miRNA

Author

Vittorio de Franciscis, Gerolama Condorelli, Carla Lucia Esposito, Francesco Geobaldo, Fabrizio Giorgis, Chiara Novara, Silvia Catuogno, Niccolo' Paccotti, Alessandro Chiadò, Paola Rivolo, Novara, Chiara, Chiado, Alessandro, Paccotti, Niccolo, Catuogno, Silvia, Esposito, CARLA LUCIA, Condorelli, Gerolama, De Franciscis, Vittorio, Geobaldo, Francesco, Rivolo, Paola, and Giorgis, Fabrizio

Subjects
Materials science, Silver, Microfluidics, Metal Nanoparticles, Nanotechnology, 02 engineering and technology, 010402 general chemistry, Spectrum Analysis, Raman, 01 natural sciences, Silver nanoparticle, Nucleic acid thermodynamics, Limit of Detection, Cell Line, Tumor, Lab-On-A-Chip Devices, Humans, SERS-active, nanostructures, microfluidic, miRNA, Physical and Theoretical Chemistry, Detection limit, Oligonucleotide, Hybridization probe, Nucleic Acid Hybridization, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Nanostructures, MicroRNAs, Membrane, 0210 nano-technology, Biosensor
Abstract

In this work, SERS-based microfluidic PDMS chips integrating silver-coated porous silicon membranes were used for the detection and quantitation of microRNAs (miRNAs), which consist of short regulatory non-coding RNA sequences typically over- or under-expressed in connection with several diseases such as oncogenesis. In detail, metal–dielectric nanostructures which provide noticeable Raman enhancements were functionalized according to a biological protocol, adapted and optimized from an enzyme-linked immunosorbent assay (ELISA), for the detection of miR-222. Two sets of experiments based on different approaches were designed and performed, yielding a critical comparison. In the first one, the labelled target miRNA is revealed through hybridization to a complementary thiolated DNA probe, immobilized on the silver nanoparticles. In the second one, the probe is halved into shorter strands (half1 and half2) that interact with the complementary miRNA in two steps of hybridization. Such an approach, taking advantage of the Raman labelling of half2, provides a label-free analysis of the target. After suitable optimisation of the procedures, two calibration curves allowing quantitative measurements were obtained and compared on the basis of the SERS maps acquired on the samples loaded with several miRNA concentrations. The selectivity of the two-step assay was confirmed by the detection of target miR-222 mixed with different synthetic oligos, simulating the hybridization interference coming from similar sequences in real biological samples. Finally, that protocol was applied to the analysis of miR-222 in cellular extracts using an optofluidic multichamber biosensor, confirming the potentialities of SERS-based microfluidics for early-cancer diagnosis.

Published
2017

189. Optimization and characterization of paper-made Surface Enhanced Raman Scattering (SERS) substrates with Au and Ag NPs for quantitative analysis

Author

Valter Sergo, Silvia Dalla Marta, Alois Bonifacio, Fabrizio Giorgis, Chiara Novara, Dalla Marta, Silvia, Novara, Chiara, Giorgis, Fabrizio, Bonifacio, Aloi, and Sergo, Valter

Subjects
Paper, Analyte, Materials science, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, lcsh:Technology, Article, symbols.namesake, Molecule, SERS substrate, General Materials Science, SERS substrates, Porosity, lcsh:Microscopy, lcsh:QC120-168.85, Nanoparticles, Materials Science (all), Filter paper, lcsh:QH201-278.5, lcsh:T, paper, Substrate (chemistry), Repeatability, nanoparticles, 021001 nanoscience & nanotechnology, 0104 chemical sciences, lcsh:TA1-2040, symbols, lcsh:Descriptive and experimental mechanics, lcsh:Electrical engineering. Electronics. Nuclear engineering, 0210 nano-technology, lcsh:Engineering (General). Civil engineering (General), lcsh:TK1-9971, Raman scattering
Abstract

In this work, we present a systematic study on solid Surface Enhanced Raman Scattering (SERS) substrates consisting of Au and Ag nanoparticles (NPs) loaded on filter paper with the dip-coating method. The aim of this work is to explore how a series of parameters (e.g., concentration of colloidal solution, different porosity of filter paper, and the presence of an aggregating agent) affects the analytical performance of paper-based SERS substrates. All the substrates developed in this study have been analyzed with two non-resonant probe molecules, 4-mercaptobenzoic acid (4-MBA) and adenine, in terms of (i) inter-sample repeatability, (ii) intra-sample repeatability, (iii) sensitivity, and (iv) overall SERS performance in terms of analyte quantification. Moreover, the issue of how to evaluate the repeatability for a solid SERS substrate is carefully discussed.

Published
2017

190. SERS-active Ag nanoparticles on porous silicon and PDMS substrates: A comparative study of uniformity and Raman efficiency

Author

Fabrizio Giorgis, Andrea Lamberti, Angelo Angelini, Francesco Geobaldo, Silvia Dalla Marta, Alessandro Chiadò, Valter Sergo, Alessandro Virga, Chiara Novara, Alois Bonifacio, Paola Rivolo, Novara, Chiara, DALLA MARTA, Silvia, Virga, Alessandro, Lamberti, Andrea, Angelini, Angelo, Chiadò, Alessandro, Rivolo, Paola, Geobaldo, Francesco, Sergo, Valter, Bonifacio, Aloi, and Giorgis, Fabrizio

Subjects
Materials science, Silicon, Physics::Optics, chemistry.chemical_element, Surfaces, Coatings and Film, Nanotechnology, 02 engineering and technology, Dielectric, 010402 general chemistry, Porous silicon, 01 natural sciences, Porous Silicon, Coatings and Films, symbols.namesake, chemistry.chemical_compound, PDMS, Electronic, Optical and Magnetic Materials, Physical and Theoretical Chemistry, Plasmon, Polydimethylsiloxane, Scattering, SERS, Electronic, Optical and Magnetic Material, 021001 nanoscience & nanotechnology, SERS, Raman spectroscopy, Plasmonics, Porous Silicon, PDMS, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Surfaces, Energy (all), General Energy, chemistry, Raman spectroscopy, symbols, Plasmonics, 0210 nano-technology, Raman scattering
Abstract

Silver-coated porous silicon and polydimethylsiloxane (PDMS) are systematically analyzed as substrates for surface-enhanced Raman scattering (SERS). They were selected as representative metal-dielectric nanostructures characterized by different morphology and substrate dielectric constant which is reflected in the electromagnetic near-field intensity spectra. The study is conducted using 4-mercaptobenzoic acid as probe molecule with the aim to compare the scattering efficiency and the homogeneity of the Raman signal on the selected substrates. A larger SERS enhancement is evidenced for the silicon-based plasmonic nanostructures (>106, despite the electronic off-resonant excitation of the analyte). On the other hand, the silvered elastomeric substrates, characterized by a good Raman efficiency, show good repeatability featured by a low inter- and intrasubstrate standard deviation of the SERS signal intensity, which make them suitable for quantitative analysis. The influence of the excitation wavelength on such properties is deeply discussed taking into account experimental results and 3D modeling.

Published
2016

191. Reverse Micelle Strategy for the Synthesis of MnO x -TiO 2 Active Catalysts for NH 3 -Selective Catalytic Reduction of NO x at Both Low Temperature and Low Mn Content.

Author

Bonelli B, Tammaro O, Martinovic F, Nasi R, Dell'Agli G, Rivolo P, Giorgis F, Ditaranto N, Deorsola FA, and Esposito S

Abstract

MnO x -TiO 2 catalysts (0, 1, 5, and 10 wt % Mn nominal content) for NH 3 -SCR (selective catalytic reduction) of NO x have been synthesized by the reverse micelle-assisted sol-gel procedure, with the aim of improving the dispersion of the active phase, usually poor when obtained by other synthesis methods (e.g., impregnation) and thereby lowering its amount. For comparison, a sample at nominal 10 wt % Mn was obtained by impregnation of the (undoped) TiO 2 sample. The catalysts were characterized by using an integrated multitechnique approach, encompassing X-ray diffraction followed by Rietveld refinement, micro-Raman spectroscopy, N 2 isotherm measurement at -196 °C, energy-dispersive X-ray analysis, diffuse reflectance UV-vis spectroscopy, temperature-programmed reduction technique, and X-ray photoelectron spectroscopy. The obtained results prove that the reverse micelle sol-gel approach allowed for enhancing the catalytic activity, in that the catalysts were active in a broad temperature range at a substantially low Mn loading, as compared to the impregnated catalyst. Particularly, the 5 wt % Mn catalyst showed the best NH 3 -SCR activity in terms of both NO x conversion (ca. 90%) and the amount of produced N 2 O (ca. 50 ppm) in the 200-250 °C temperature range., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Published
2021
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192. Direct patterning of silver particles on porous silicon by inkjet printing of a silver salt via in-situ reduction.

Author

Chiolerio A, Virga A, Pandolfi P, Martino P, Rivolo P, Geobaldo F, and Giorgis F

Abstract

We have developed a method for obtaining a direct pattern of silver nanoparticles (NPs) on porous silicon (p-Si) by means of inkjet printing (IjP) of a silver salt. Silver NPs were obtained by p-Si mediated in-situ reduction of Ag+ cations using solutions based on AgNO3 which were directly printed on p-Si according to specific geometries and process parameters. The main difference with respect to existing literature is that normally, inkjet printing is applied to silver (metal) NP suspensions, while in our experiment the NPs are formed after jetting the solution on the reactive substrate. We performed both optical and scanning electron microscopes on the NPs traces, correlating the morphology features with the IjP parameters, giving an insight on the synthesis kinetics. The patterned NPs show good performances as SERS substrates.

Published
2012
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