Lorena Carla Giannossa

An innovative, easily fabricated, silver nanoparticle-based titanium implant coating: development and analytical characterization

AbstractMicrobial colonization and biofilm formation on implanted devices represent an important complication in orthopaedic and dental surgery and may result in implant failure. Controlled release of antibacterial agents directly at the implant site may represent an effective approach to treat these chronic complications. Resistance to conventional antibiotics by pathogenic bacteria has emerged in recent years as a major problem of public health. In order to overcome this problem, non-conventional antimicrobial agents have been under investigation. In this study, polyacrylate-based hydrogel thin coatings have been electrosynthesised on titanium substrates starting from poly(ethylene glycol diacrylate)–co–acrylic acid. Silver nanoparticles (AgNPs) with a narrow size distribution have been synthesized using a “green” procedure and immobilized on Ti implant surfaces exploiting hydrogel coatings’ swelling capabilities. The coatings have been characterized by XPS and SEM/EDX, while their silver release performances have been monitored by ICP–MS. The antibacterial activity of these AgNP-modified hydrogel coatings was tested evaluating in vitro inhibition growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, among the most common pathogens in orthopaedic infections. Moreover, a preliminary investigation of the biocompatibility of silver-loaded coatings versus MG63 human osteoblast-like cells has been performed. An important point of strength of this paper, in fact, is the concern about the effect of silver species on the surrounding cell system in implanted medical devices. Silver ion release has been properly tuned in order to assure antibacterial activity while preserving osteoblasts’ response at the implant interface. FigureSilver nanoparticles-loaded PEGDA-AA hydrogel coatings for inhibition of titanium implants associated infections

Palladium/Zirconium Oxide Nanocomposite as a Highly Recyclable Catalyst for C-C Coupling Reactions in Water

Palladium nanoparticles have been electrochemically supported on zirconium oxide nanostructured powders and all the nanomaterials have been characterized by several analytical techniques. The Pd/ZrO2 nanocatalyst is demonstrated to be a very efficient catalyst in Heck, Ullmann, and Suzuki reactions of aryl halides in water. The catalyst efficiency is attributed to the stabilization of Pd nanophases provided by tetra(alkyl)-ammonium hydroxide, which behaves both as base and PTC (phase transfer catalyst) agent.

Metal nanoantimicrobials for textile applications

Abstract Research on the 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 the selected studies in the field of antimicrobial textiles, employing bioactive nanophases 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 the deposition/preparation methods, which are being used in the authors’ labs for the development of the textiles modified by the novel nanoantimicrobials.

A multianalytical study of archaeological faience from the Vesuvian area as a valid tool to investigate provenance and technological features

The investigation was aimed at defining the compositional and structural characteristics of a group of monochrome blue faiences recovered in Pompeii to assess provenance on the basis of their technological features. Different complementary analytical techniques were used: Scanning Electron Microscopy (SEM) to investigate the morphological aspects of the samples and in particular of the interfaces, micro-Raman Spectroscopy and XRPD to identify crystalline phases and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to assess the elemental composition due to its sensitivity to a wide range of elements and the adequate lateral resolution. Statistical data treatment of the elemental concentrations of both the ceramic bodies and the glazes allowed us to classify the objects into compositional groups and to verify the previously established archaeological hypothesis suggesting an Egyptian provenance for faience of Pompeii.

Towards highly stable aqueous dispersions of multi-walled carbon nanotubes: the effect of oxygen plasma functionalization

In order to improve the dispersion of multi-walled carbon nanotubes (MWCNTs) in aqueous media, their surface functionalization was carried out in O2-fed low-pressure plasmas. Differently from what can be found in the literature of this field, homogeneous functionalization was achieved by generating the plasma inside vials containing the nanotube powders properly stirred. Experimental parameters, such as input power, treatment time and pressure, were varied to investigate their influence on the process efficiency. A detailed characterization of the plasma treated nanotubes, dry and in aqueous suspension, was carried out with a multi-diagnostic analytical approach, to evaluate their surface chemical properties, morphology, structural integrity and stability in the colloidal state. The plasma grafting of polar ionizable (e.g. acid) groups has been proved to successfully limit the agglomeration of MWCNTs and to produce nanotubes suspensions that are stable for one month and more in water.

Characterization and behaviour of ZnO-based nanocomposites designed for the control of biodeterioration of patrimonial stoneworks

In this study, a preventive method for fighting bio-deterioration of stone substrates is proposed. This is based on the use of bioactive zinc oxide nanoparticles (ZnO-NPs), which are able to exert a marked biological activity over a long period of time due to their peculiar structure. ZnO-NPs are synthesised by a simple and reproducible electrochemical procedure. The nanomaterials are embedded in consolidant/water-repellent matrices to obtain nanostructured coatings. Commonly used products based on tetraethoxysilane and/or polysiloxanes were tested. The resulting nanomaterials were fully characterised by X-ray photoelectron spectroscopy (XPS) to investigate the amount and composition of the NPs and the behaviour of the nanocomposites. Inductively coupled plasma mass spectrometry (ICP-MS) was used for the study of the release of metal from the composites when put in contact with artificial rainwater. The nanocomposites were applied to specimens composed of three different types of stone and chromatic changes upon curing were measured by spectrophotocolorimetry. Finally, morphological characterization by scanning electron microscopy (SEM) was performed. The bioactivity of ZnO-NPs nanocomposites was also assessed in preliminary tests against Aspergillus niger fungus.

Methodology of a combined approach: analytical techniques to identify the technology and raw materials used in thin-walled pottery from Herculaneum and Pompeii

This study focuses on defining compositional and structural characteristics, identifying raw materials and production technology, and validating the archaeological hypothesis of a local production of thin-walled pottery (2nd cent. BC–3rd cent. AD) in the Vesuvian area. Samples investigated were analysed using OM, SEM-EDS, XRD and LA-ICPMS supported by a statistical multivariate treatment of the compositional data of the ceramic bodies. The results obtained show how an integrated approach of analytical techniques can provide answers to archaeological questions and also give a valuable insight into the exchange of raw materials and/or finished products between sites. The paper also discloses how a combined analytical methodology represents a positive step in answering the one question which remains unsolved concerning the entire ceramic production in the Vesuvian area: the provenance of the clayey raw materials used. Indeed, the massive pottery production in the Bay of Naples down the ages contrasts with the unavailability of the necessary clayey local resources.

A systematic characterization of fibulae from Italy: from chemical composition to microstructure and corrosion processes

Fibulae from the archaeological site of Egnatia were examined with the aim of identifying types of alloys, the processes employed for their manufacturing, and outlining the corrosion products. The results obtained, by identifying the raw materials and the technological solutions used allowed us to provide convincing answers to most of the archaeological questions and confirmed the integration of Egnatia in a complex commercial network. In addition, investigations focused on the study of corrosion products, with a view to the planning of more suitable restoration and preservation strategies.

An archaeometric approach to gain knowledge on technology and provenance of Apulian red-figured pottery from Taranto

A large sampling of Apulian red-figured pottery fragments (fifth to fourth century BC) coming from Taranto (Italy) was analyzed by a multi-technique approach. The ceramic bodies’ elemental composition has been obtained by inductively coupled plasma mass spectrometry (ICP-MS), the mineralogical composition of pastes by polarized-light optical and electron microscopies (OM and SEM-EDS), and X-ray powder diffraction (PXRD). The results obtained from the statistical treatment of compositional data, combined with those driven from mineralogical composition of pastes, allow to formulate hypotheses about the provenance of the objects and the manufacturing tradition of the workshops, starting to make it possible to understand the relationships among ceramic technology, artistic expression, and workshop practice in the samples analyzed.

Integrated investigations for the characterisation of Roman lead-glazed pottery from Pompeii and Herculaneum (Italy)

A multi-analytical approach was used to investigate Roman lead-glazed ceramic artefacts from archaeological excavations at Pompeii and Herculaneum (Italy) aiming at defining the production technology of both glaze and ceramic body, by way of integrated investigations. The chemical, structural, and micro-morphological characterisations were performed using a combination of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), optical microscopy (OM), scanning electron microscopy (SEM), and micro-Raman spectroscopy. Fragments of artefacts (skyphoi, oil lamps, bowls, askoi, amphorae, krateres) of great historical and archaeological interest were sampled. LA-ICP-MS was used to determine the elemental composition by virtue of its effective lateral resolution, its ability to detect most elements and also to analyse comparably small samples. All the archaeological objects were coated with a lead-based glaze produced using a lead oxide-plus-quartz mixture, with sodium/potassium feldspars added as a flux and two different metals used: copper and iron. Two types of ceramic pastes have been identified, but chemometric techniques support the hypothesis of a Campanian provenance for the raw materials. Degradation phenomena such as the partial devitrification of the glaze, i.e. the slow structural reorganisation towards stable crystalline phases, and the leaching by mineral dissolution in the soil, were determined.