Nicola Cioffi

Università degli Studi di Bari Aldo Moro, Bari, Apulia, Italy

Are you Nicola Cioffi?

Claim your profile

Publications (121)307.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Ternary CuxSnySz thin films with different Cu/Sn atomic ratios and thicknesses have been electrochemically deposited on the (111) face of a silver single crystal. The surface morphology and chemical composition of these chalcogenides, which have attracted considerable worldwide interest as low cost high conversion efficiency photovoltaic devices, have been characterized by means of SEM, parallel angle resolved (PAR-XPS) and TOF-SIMS depth profiling in order to gain insight into the morphology and element distribution within the layer and their effect on the band gap. This study constitutes the first in-depth chemical study on CuxSnySz thin films, providing evidence of notable discrepancies between the expected and real composition, especially regarding the Cu/Sn ratio. The samples were found to be chemically homogeneous through the whole deposit even though strongly tin depleted regardless their thickness or deposition sequence. Finally, the literature band gap data were discussed on the basis of these findings.
    Solar Energy Materials and Solar Cells 07/2015; 138:9-16. DOI:10.1016/j.solmat.2015.02.029 · 5.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ultrasensitive biosensors based on bottom gate organic field-effect transistors can be developed by depositing a functional biological (protein) interlayer directly on the silicon oxide gate dielectric and underneath the organic semiconductor film. However, the deposition methods for assembling the protein biological recognition layer can affect the biosensor analytical performances for the target analyte detection. Here, spin-coating and layer-by-layer techniques were considered as different approaches for streptavidin protein deposition. X-ray photoelectron spectroscopy (XPS) was systematically used in the non-destructive parallel angle resolved mode to characterize the multilayer device at each step of its assembly to gain information on elemental depth profiles. Scanning electron and scanning Helium ion microscopies gave information about stacked layer structure and morphology corroborating XPS results.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Copper(II) chloride catalyses the oxidative carbonylation of aminols, amine and alcohols to give 2-oxazolidinones, ureas and carbamates. Reaction proceeds smoothly in water under homogeneous conditions (Ptot= 4 MPa; PO2 = 0.6 MPa, PCO), at 100 °C in relatively short reaction times (4 h) and without using bases or any other additives. This methodology represents an economic and environmentally benign non-phosgene alternative for the preparation of these three important N-containing carbonyl compounds.
    Journal of Molecular Catalysis A Chemical 06/2015; DOI:10.1016/j.molcata.2015.06.007 · 3.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gold nanoparticles stabilized on metal oxide supports have found a wide range of applications especially in heterogeneous catalysis and gas sensing. A facile methodology for the in situ electrodecoration of gold nanoparticles on metal oxide supports is presented herein. Metal oxides such as indium oxide (In2O3) and zirconia (ZrO2) nanoparticles are first prepared via the sol–gel route. Subsequently, gold nanoparticles are electrodeposited in situ on the surface of these metal oxides using a modified sacrificial Au-anode electrolysis procedure. Both pristine as well as electrodecorated metal oxides are characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM, TEM). SEM images of electrodecorated metal oxides reveal successful deposition of gold nanoparticles on metal oxide supports. XPS shows that nano-sized gold is significantly available on the materials' surface and it is in the elemental oxidation state. Moreover, it is found that the electrodecoration of gold nanoparticles on metal oxide surfaces proceeds as a function of the concentration of hydroxyl groups on the surface of metal oxide supports.
    Materials Express 06/2015; 5(3). DOI:10.1166/mex.2015.1226 · 1.72 Impact Factor
  • Source
    Nanotechnology in Diagnosis, Treatment and Prophylaxis of Infectious Diseases, 1 edited by Katerina Kon, Mahendra Rai, 05/2015: chapter Chapter 6: pages 87-105; Elsevier., ISBN: 978-0-12-801317-5
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Designing bioactive materials, with controlled metal ion release, exerting significant bioactivity and associated low toxicity for humans, is nowadays one of the most important challenges for the scientific community. In this work, we propose a new material combining the well-known antimicrobial properties of copper nanoparticles (CuNPs) with those of bioactive chitosan (CS), a cheap natural polymer widely exploited for its biodegradability and nontoxicity. Here, we used ultrafast femtosecond laser pulses to finely fragment, via laser ablation, a Cu solid target immersed into aqueous CS solutions. Homogeneously dispersed copper-chitosan (Cu-CS) colloids were obtained by tuning the Cu/CS molar ratios, according to the initial chitosan concentration, as well as other experimental parameters. Cu-CS colloids were characterized by several techniques, like UV-Vis and X-ray Photoelectron spectroscopies (XPS). Transmission Electron Microscopy (TEM) was used to morphologically characterize the novel nanocomposites.
    MRS Online Proceeding Library 05/2015; 1804. DOI:10.1557/opl.2015.611
  • Source
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag2O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. Copyright © 2015 Elsevier B.V. All rights reserved.
    Materials Science and Engineering C 03/2015; 52:1-10. DOI:10.1016/j.msec.2015.03.035 · 2.74 Impact Factor
  • Source
    Solar Energy Materials and Solar Cells 03/2015; 138:9-16. · 5.03 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The phospholipidomic signatures of human blood microparticles and platelets, evaluated by hydrophilic interaction liquid chromatography coupled to electrospray ionization-mass spectrometry, were compared. The phospholipidome of platelet-derived microparticles, obtained by platelets stimulation with a mixture of Ca(II), thrombin and collagen, was also considered for the comparison. Platelets, blood microparticles and platelet-derived microparticles displayed qualitatively similar phospholipidomes, all based on eight major phospholipid classes, namely: phosphatidylcholines, diacyl- and plasme(a)nyl-phosphatidylethanolamines, phosphatidylserines, phosphatidylinositols, sphingomyelins and lyso forms of phosphatidylcholines and phosphatidylethanolamines. However, while the phospholipidomes of platelets and platelet-derived microparticles were found to be generally similar also from a quantitative point of view, a higher relative incidence of species bearing polyunsaturated side chains, especially in phospholipid classes sharing the choline head (i.e. phosphatidylcholines and lyso-phosphatidylcholines), was observed in the case of blood microparticles. As a further peculiar feature, never reported before, the relative abundance of lyso-phosphatidylcholines among the eight identified phospholipid classes was found to be significantly higher in the lipid extracts of blood microparticles.
    Lipids 01/2015; 50(1):71-84. DOI:10.1007/s11745-014-3975-7 · 2.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Automobile exhaust gas emissions are causing serious damage to urban air quality in and around major cities of the world, which demands continuous monitoring of exhaust emissions. The chief components of automobile exhaust include carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons. Indium zirconate (InZrOx) and gold/indium zirconate (Au/InZrOx) composite nanopowders are believed to be interesting materials to detect these substances. To this end, characterization and gas sensing properties of InZrOx and Au/InZrOx composite nanopowders are discussed. InZrOx nanoparticles with In/Zr atomic ratio of 1.00 (±0.05) are synthesized via pH-controlled co-precipitation of In and Zr salts in aqueous ammonia. Gold (Au) nanoparticles are subsequently deposited on InZrOx using an in situ sacrificial Au electrolysis procedure. The products are characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The gas sensing performance of Au/InZrOx composite nanopowder is studied by depositing a thick powder film on interdigitated electrode structures patterned on SiC substrate to facilitate high temperature operation. The resistivity of the Au/InZrOx layer is the sensor signal, and the sensors could be operated at 500-600 °C, which is a suitable temperature range for engine exhaust measurements. The control sensing measurements reveal that Au/InZrOx composite nanopowder exhibits higher response towards 2-20 % O2 gas as compared to pristine InZrOx nanoparticles. Further studies show that when applied to exhaust gases such as CO and nitric oxide (NO), the response of Au/InZrOx sensors is significantly higher towards NO in this temperature range. Thus, sensor performance characteristics of Au/InZrOx composite nanopowder are promising in terms of their applications in automobile exhaust emission control.
    Journal of Solid State Electrochemistry 01/2015; DOI:10.1007/s10008-015-2900-1 · 2.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An innovative one-step approach based on femtosecond laser ablation synthesis in aqueous solution is presented for the development of copper nanoparticle-chitosan (CuNP-CS) nano-antimicrobials. The influence of the CS concentration has been assessed, in order to tune the morphological and chemical features of the as-prepared nanomaterial. CuNP-CS hybrid nanocolloids have been characterized by TEM and XPS techniques. Ultrafine and almost monodisperse CuNPs are obtained at a CS concentration of 1 g/L.
    Materials Letters 12/2014; 136. DOI:10.1016/j.matlet.2014.08.083 · 2.27 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The antimicrobial properties of metals such as silver and copper have been known for centuries whereas the use of nanostructures and nanotechnology in antimicrobial strategies is an emerging area of research. Recently, the confluence of nanotechnology and the search for new agents in the fight against microbes with multi-drug resistance has brought metals in the form of nanoparticles (NPs) to the fore as potential antimicrobial agents. NPs have unique and well-defined physical and chemical properties that can be manipulated for desired applications, and the antimicrobial efficacy of metallic NPs is highly dependent on their large surface area to volume ratio. In this chapter, we review the properties of a range of metal and metal oxide NPs, such as those derived from copper, silver, zinc, and so on, along with different strategies for their development. In addition, we describe potential applications of NPs as antimicrobials in areas such as medical devices, the food industry, and textile fabrics.
    Novel Antimicrobial Agents and Strategies, Edited by David A. Phoenix, Frederick Harris, Sarah R. Dennison, 11/2014: chapter Nano‐Antimicrobials Based on Metals: pages 181-218; Wiley., ISBN: 9783527676132
  • [Show abstract] [Hide abstract]
    ABSTRACT: In the present study, Au-surfactant core-shell colloidal nanoparticles (NPs) with controlled dimension and composition were synthesized by sacrificial anode electrolysis. Transmission electron microscopy (TEM) revealed that Au NPs core diameter is between 8 and 12 nm, as a function of the electrosynthesis conditions. Moreover, surface spectroscopic characterization by X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of nanosized gold phase. Controlled amounts of Au NPs were then deposited electrophoretically on carbon nanotube (CNT) networked films. The resulting hybrid materials were morphologically and chemically characterized using TEM, SEM (scanning electron microscopy) and XPS analyses, which revealed the presence of nanoscale gold, and its successful deposition on CNTs. Au NP/CNT networked films were tested as active layers in a two-pole resistive NO2 sensor for sub-ppm detection in the temperature range of 100–200 °C. Au NP/CNT exhibited a p-type response with a decrease in the electrical resistance upon exposure to oxidizing NO2 gas and an increase in resistance upon exposure to reducing gases (e.g. NH3). It was also demonstrated that the sensitivity of the Au NP/CNT-based sensors depends on Au loading; therefore, the impact of the Au loading on gas sensing performance was investigated as a function of the working temperature, gas concentration and interfering gases.
    10/2014; 3:245–252. DOI:10.5194/jsss-3-245-2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: The surface chemistry of gold nanowires (AuNWs) has been systematically assessed in terms of contamination and cleaning processes. The nanomaterial's surface quality was correlated to its performance in the matrix-free laser desorption ionization mass spectrometry (LDI-MS) analysis of low molecular weight analytes. Arrays of AuNWs were deposited on glass slides by means of the lithographically patterned nanowire electrodeposition technique. AuNWs were then characterized in terms of surface chemical composition and morphology using X-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. AuNWs were subjected to a series of well-known cleaning procedures with the aim of producing the best performing surfaces for the LDI-MS detection of leucine enkephalin, chosen as a model analyte with a molar mass below 1,000 g/mol. Prolonged cyclic voltammetry in 2 M sulfuric acid and, most of all, oxygen plasma cleaning for 5 min provided the best results in terms of simpler (interference-free) and more intense mass spectrometry spectra of the reference compound. The analyte always ionized as the sodiated adduct, and leucine enkephalin limits of detection of 0.5 and 2.5 pmol were estimated for the positive and negative analysis modes, respectively. This study points out the tight correlation existing between the chemical status of the nanostructure surface and the AuNW-assisted LDI-MS performance in terms of reproducibility of spectra, intensity of analyte ions and reduction of interferences.
    Analytical and Bioanalytical Chemistry 07/2014; 406(19). DOI:10.1007/s00216-014-7876-7 · 3.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A new class of nano-antimicrobials was developed by Ion Beam co-Sputtering of ZnO and polytetrafluoroethylene targets. The resulting nanostructured coatings combine the antimicrobial properties of ZnO nanoparticles with the water repellence and anti-stain characters of the dispersing fluoropolymer (CFx). ZnO-CFx nanocomposites with variable ZnO volume fraction (phi) in the CFx matrix were prepared by tuning the sputtering deposition parameters. Morphological analysis confirmed the presence of homogenously distributed ZnO nanoclusters in the polymer. ZnO loadings ranging in the 0.05-0.15 interval were explored and the nanocomposites were characterized by X-ray Photoelectron Spectroscopy (XPS) to investigate their surface chemical composition. XPS spectra evidenced a high degree of polymer defluorination along with the formation of ZnF2 at increasing phi values. Zn speciation was performed on Zn L3M45M45 Auger signal. Coatings bioactivity was assessed against Escherichia coli, Staphylococcus aureus, and Kluyveromyces marxianus. At phi >= 0.10, ZnO-CFx composites exhibited appreciable antibacterial activity, irrespective of the target organism.
    Science of Advanced Materials 05/2014; 6(5):1019-1025. DOI:10.1166/sam.2014.1852 · 2.91 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gold (Au) nanoparticles stabilized on metal oxide supports offer superior catalytic activity and recyclability in organic catalysis. We report for the first time synthesis of indium oxide stabilized gold (Au@In2O3) nanocatalysts using an electrochemical procedure and their application in homocoupling of arylboronic acids. In2O3 nanoparticles prepared via sol-gel process are subjected to sacrificial anode electrolysis (SAE) under inert condition for electrodeposition of nano Au on In2O3. Thus Au@In2O3 nanoparticles obtained are thermally annealed at high temperature to partially oxidize Au and to remove any surfactants. XPS results show the existence of both elemental (nano Au) and cationic (Au3+) species in Au@In2O3 nanocatalysts, while SEM images confirm the presence of nanoscale Au (< 10 nm) particles on In2O3 surface. Au@In2O3 nanocatalysts are tested for arylboronic acids homocoupling under different conditions and it is found that they are highly active in organic medium with K2CO3 base and demonstrate excellent conversion (> 97%) and selectivity (> 98%). The catalyst recyclability and performance towards differently substituted arylboronic acids is also studied and a plausible mechanism of action is proposed.
    Journal of Molecular Catalysis A Chemical 05/2014; 386. DOI:10.1016/j.molcata.2014.01.030 · 3.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Silicon nanowires have been obtained by means of chemical etching and electron beam evaporation, spectroscopically characterized and then used as non-conventional promoters of desorption and ionization phenomena in the LDI-MS analysis of low-molecular weight species.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the present work was to compare the mucoadhesive and efflux pump P-gp interacting properties of chitosan (CS)- and glycolchitosan (GCS)-based thiomers and corresponding unmodified parent polymers. For this purpose, the glycol chitosan-N-acetyl-cysteine (GCS-NAC) and glycol chitosan-glutathione (GCS-GSH) thiomers were prepared under simple and mild conditions. Their mucoadhesive characteristics were studied by turbidimetric and zeta potential measurements. The P-gp interacting properties were evaluated measuring the effects of thiolated- and unmodified-polymers on the bidirectional transport (B→A/A→B) of Rhodamine-123 across Caco-2 cells as well as in the Calcein AM and ATPase activity assays. Although all the thiomers and unmodified polymers showed optimal-excellent mucoadhesive properties, the best mucoadhesive performances have been obtained by CS and CS-based thiomers. Moreover, it was found that the pretreatment of Caco-2 cell monolayer with GCS-NAC or GCS restores Rho-123 cell entrance by inhibiting P-gp activity. Hence, GCS-NAC and GCS may constitute new biomaterials useful for improving the bioavailability of P-gp substrates.
    Biomacromolecules 02/2014; 15(3). DOI:10.1021/bm401733p · 5.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present work is aimed at developing gold nanostructures functionalized with antenna systems to exploit the synergistic nanostructure/antenna desorption-ionization efficiency. A potential Matrix-Assisted Laser Desorption Ionisation (MALDI) organic matrix has been modified introducing specific functional groups or molecular linker and used as a capping agent for gold nanostructures. In particular, conjugated naphthyl-thio-derivative, i.e. 4-mercaptonaphthalene-1,8-dicarboxylic acid, was synthesized and characterized by means of nuclear magnetic resonance, UV-visible and X-ray photoelectron spectroscopies. Afterwards, the thio-derivative was used as covalent surface modifier for flat gold surfaces and nanostructured gold films. These surfaces were thoroughly characterized by means of parallel angle-resolved X-ray photoelectron spectroscopy to obtain quantitative information about elemental composition, chemical speciation, and in-depth distribution of the target chemical functional groups. Finally the compound was preliminarily tested as a non-conventional matrix in Laser Desorption Ionisation Mass Spectrometry (LDI-MS) analysis of low molecular weight biomolecules in order to assess its capability of acting as the antenna system and proton donor after covalent bonding to gold nanomaterials. (c) 2013 Elsevier Ltd. All rights reserved.
    Vacuum 02/2014; 100:78-83. DOI:10.1016/j.vacuum.2013.07.032 · 1.43 Impact Factor