Nicola Cioffi

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

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Publications (111)295.19 Total impact

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    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
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    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 fibres. 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.
    Materials Science and Engineering C 03/2015; 03(35). DOI:10.1016/j.msec.2015.03.035 · 2.74 Impact Factor
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    Solar Energy Materials and Solar Cells 03/2015; 138:9-16. · 5.03 Impact Factor
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    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 · 2.56 Impact Factor
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    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
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    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
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    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
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    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 · 3.66 Impact Factor
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    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
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    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
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    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.
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    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
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    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
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    MRS Online Proceeding Library 01/2014; 1675. DOI:10.1557/opl.2014.847
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    ABSTRACT: In this work, the unique capability of femtosecond laser pulses to finely fragment via laser ablation a Cu solid target immersed into CS-HAc solutions was exploited in order to obtain a homogeneously dispersed colloid of Cu-CS nanocomposites with different Cu/CS molar ratios according to the initial chitosan concentration. Using these hybrid nanocolloids as solvents, well-dispersed nanocomposite polymer films were produced after spin-coating on glass substrates. Both Cu-CS colloids and coatings were characterized by several techniques, including UV-Vis, FTIR, DLS, TEM and XPS aiming to analyse the surface and bulk chemical composition as well as the morphology of the novel nanocomposite. The antimicrobial properties of the proposed hybrid Cu-CS nanomaterial, which in the intention combines the bioactivity of both components, have been assessed by biological experiments using selected microorganism strains including samples from hospitalized dermatology patients.
    The European Conference on Lasers and Electro-Optics; 05/2013
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    ABSTRACT: One- and two-dimensional carbon nanostructures, i.e. carbon nanotubes (CNTs) and graphene possess exceptional physical properties owing to their distinctive structure and atomic arrangement. High electrical conductivity, highly exposed surface area and stability of these carbon nanostructures institute them as the leading choice of nanomaterials for a number of electrical and industrial applications. Besides these carbon nanostructures are extremely sensitive toward minute changes in the surrounding gas atmosphere, i.e. their conductance (or resistance) varies greatly with the adsorption–desorption of gas molecules such as nitrogen oxides (NOx). This article critically reviews the most recent advances in NOx sensors based on one- and two-dimensional carbon nanostructures and nanohybrids as gas sensitive materials. The advantages and limitations of CNT- and graphene-based devices are briefly discussed in the light of recent literature. The potential and future perspectives of these devices are also outlined in this study.
    Sensors and Actuators B Chemical 05/2013; 181. DOI:10.1016/j.snb.2013.01.089 · 3.84 Impact Factor
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    ABSTRACT: In this paper a study of Multi Wall Carbon Nanotube films deposited at low temperature by means of a spray tech-nique on different substrates is presented. Nanodispersion of nanotube powder in a non-polar 1,2-dichloroethane solvent was used as starting solution. Electron Microscopy in Scanning and Transmission modes were used in order to verify the morphological properties of the deposited films. Visible light detectors were prepared spraying Multi Wall Carbon Nanotubes on silicon substrates with different lay-outs. In some detectors the nanotubes were covered by an Indium Tin Oxide (ITO) layer. Electrical measurements, both in dark and under light irradiation, were performed and Current-Voltage characteristics are reported. The Indium Tin Oxide coating effect on the photoconductivity yield is presented and discussed along with device ageing test, resulting in a very good photoconduction and stability over four months.
    Thin Solid Films 04/2013; DOI:10.1016/j.tsf.2013.03.079 · 1.87 Impact Factor
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    ABSTRACT: Research on nanomaterials containing one or more transition metals is growing tremendously, thanks to the large number of preparation processes available, and to the novel applications that can be envisaged in several fields. This review presents an overview of selected studies in the field of antimicrobial textiles, employing bioactive nano-phases of elements/compounds such as silver, copper or zinc oxide. In addition, the history of use of these antimicrobials and their mechanism of action are shortly reported.. Finally, a short description is provided of deposition/preparation methods which are being used in the authors labs for the development of textiles modified by novel nanoantimicrobials.
    04/2013; DOI:10.1515/ntrev-2013-0004
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    ABSTRACT: The aim of this study was to evaluate the performance of chitosan (CS) and glycol chitosan (GCS) nanoparticles containing the surfactant Lipoid S100 for the systemic delivery of low molecular weight heparin (LMWH) upon pulmonary administration. These nanoparticles were prepared in acidic and neutral conditions using the ionotropic gelation technique. The size and zeta potential of the NPs were affected by the pH and also the type of polysaccharide (CS or GCS). The size (between 156 and 385nm) was smaller and the zeta potential (from +11mV to +30mV) higher for CS nanoparticles prepared in acidic conditions. The encapsulation efficiency of LMWH varied between 100% and 43% for the nanoparticles obtained in acidic and neutral conditions, respectively. X-ray photoelectron spectroscopy studies indicated that the surfactant Lipoid S100 was localized on the nanoparticle's surface irrespective of the formulation conditions. In vivo studies showed that systems prepared in acidic conditions did not increase coagulation times when administered to mice by the pulmonary route. In contrast, Lipoid S100-LMWH GCS NPs prepared in neutral conditions showed a pharmacological efficacy. Overall, these results illustrate some promising features of CS-based nanocarriers for pulmonary delivery of LMWH.
    International Journal of Pharmaceutics 02/2013; DOI:10.1016/j.ijpharm.2013.02.035 · 3.99 Impact Factor
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    ABSTRACT: AbstractA plasma deposition (PE‐CVD) process is proposed to functionalize the surface of P3HT organic semiconductor with an hydrophilic coating characterized by carboxyl groups. The functionalized P3HT is employed as electronic active layer in an electrolyte gated organic field‐effect transistor (EGOFET). Nanometric coatings were plasma deposited at the surface of P3HT from glow discharges fed with ethylene and acrylic acid vapors. The surface chemical composition of coated P3HT along with its wettability, have been assessed by means of X‐ray photoelectron spectroscopy and water contact angle. Results show that PE‐CVD is a valid approach to functionalize P3HT surfaces with carboxyl groups, leaving negligible adverse effect on the EGOFET performances. Possibly, chemical or biological species could be immobilized on PE‐CVD‐functionalized EGOFETs, opening to further developments in their use as sensors.
    Plasma Processes and Polymers 02/2013; 10(2). DOI:10.1002/ppap.201200080 · 2.96 Impact Factor