Nicoletta Ditaranto

Antifungal activity of polymer-based copper nanocomposite coatings

Eukaryotes, such as fungi, can be harmful pathogen agents, and the control of their bioactivity is critical as humans are eukaryote organisms, too. Here, copper∕polymer nanocomposites are proposed as antifungal spinnable coatings with controlled copper-releasing properties. The tests of the bioactivity show that fungal growth is inhibited on the nanocomposite-coated plates, and the antifungal activity can be modulated by controlling the Cu nanoparticle loading.

Analytical characterization of laser-generated copper nanoparticles for antibacterial composite food packaging

AbstractA new type of nanomaterial has been developed as antibacterial additive for food packaging applications. This nanocomposite is composed of copper nanoparticles embedded in polylactic acid, combining the antibacterial properties of copper nanoparticles with the biodegradability of the polymer matrix. Metal nanoparticles have been synthesised by means of laser ablation, a rising and easy route to prepare nanostructures without any capping agent in a liquid environment. As prepared, nanoparticle suspensions have been easily mixed to a polymer solution. The resulting hybrid solutions have been deposited by drop casting, thus obtaining self-standing antibacterial packages. All samples have been characterized by UV–Vis spectroscopy, X-ray photoelectron spectroscopy and electro-thermal atomic absorption spectroscopy. Ion release data have been matched with bioactivity tests performed by Japanese Industrial Standard (JIS) method (JIS Z 2801:2000) against Pseudomonas spp., a very common Gram-negative microbial group able to proliferate in processed food. Online abstract figureAnalytical characterization of copper nanoparticles: an XPS spectrum and a TEM image

Systemic heparin delivery by the pulmonary route using chitosan and glycol chitosan nanoparticles

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 385 nm) was smaller and the zeta potential (from +11 mV to +30 mV) 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 nanoparticles 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.

Analytical characterization of chitosan nanoparticles for peptide drug delivery applications.

Chitosan-cyclodextrin hybrid nanoparticles (NPs) were obtained by the ionic gelation process in the presence of glutathione (GSH), chosen as a model drug. NPs were characterized by means of transmission electron microscopy and zeta-potential measurements. Furthermore, a detailed X-ray photoelectron spectroscopy study was carried out in both conventional and depth-profile modes. The combination of controlled ion-erosion experiments and a scrupulous curve-fitting approach allowed for the first time the quantitative study of the GSH in-depth distribution in the NPs. NPs were proven to efficiently encapsulate GSH in their inner cores, thus showing promising perspectives as drug carriers.

Highly selective detection of Epinephrine at oxidized Single-Wall Carbon Nanohorns modified Screen Printed Electrodes (SPEs).

Oxidized Single-Wall Carbon Nanohorns (o-SWCNHs) were used, for the first time, to assemble chemically modified Screen Printed Electrodes (SPEs) selective towards the electrochemical detection of Epinephrine (Ep), in the presence of Serotonine-5-HT (S-5HT), Dopamine (DA), Nor-Epineprhine (Nor-Ep), Ascorbic Acid (AA), Acetaminophen (Ac) and Uric Acid (UA). The Ep neurotransmitter was detected by using Differential Pulse Voltammetry (DPV), in a wide linear range of concentration (2-2500 μM) with high sensitivity (55.77 A M(-1) cm(-2)), very good reproducibility (RSD% ranging from 2 to 10 for different SPEs), short response time for each measurement (only 2s) and low detection of limit (LOD=0.1 μM). o-SWCNHs resulted in higher analytical performances when compared with other nanomaterials used in literature for electrochemical sensors assembly.

Synthesis and analytical characterisation of copper-based nanocoatings for bioactive stone artworks treatment

AbstractBiological agents play an important role in the deterioration of cultural heritage causing aesthetic, biogeophysical and biogeochemical damages. Conservation is based on the use of preventive and remedial methods. The former aims at inhibiting biological attack, and the latter aims at eradicating the biological agents responsible for biodeterioration. Here, we propose the preparation and the analytical characterisation of copper-based nanocoating, capable of acting both as a remedy and to prevent microbial proliferation. Core–shell CuNPs are mixed with a silicon-based product, commonly used as a water-repellent/consolidant, to obtain a combined bioactive system to be applied on stone substrates. The resulting coatings exert a marked biological activity over a long period of time due to the continuous and controlled release of copper ions acting as biocides. To the best of our knowledge, this is the first time that a multifunctional material is proposed, combining the antimicrobial properties of nanostructured coatings with those of the formulations applied to the restoration of stone artworks. A complete characterisation based on a multi-technique analytical approach is presented. Online abstract figureRelease properties and morphological features of copper-based nanocoatings.

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.

1,8-Bis(dimethylamino)naphthalene/9-aminoacridine: A new binary matrix for lipid fingerprinting of intact bacteria by matrix assisted laser desorption ionization mass spectrometry

The effectiveness of a novel binary matrix composed of 1,8-bis(dimethylamino)naphthalene (DMAN; proton sponge) and 9-aminoacridine (9AA) for the direct lipid analysis of whole bacterial cells by matrix assisted laser desorption ionization mass spectrometry (MALDI MS) is demonstrated. Deprotonated analyte signals nearly free of matrix-related ions were observed in negative ion mode. The effect of the most important factors (laser energy, pulse voltage, DMAN/9AA ratio, analyte/matrix ratio) was investigated using a Box-Behnken response surface design followed by multi-response optimization in order to simultaneously maximize signal-to-noise (S/N) ratio and resolution. The chemical surface composition of single or mixed matrices was explored by X-ray photoelectron spectroscopy (XPS). Moreover, XPS imaging was used to map the spatial distribution of a model phospholipid in single or binary matrices. The DMAN/9AA binary matrix was then successfully applied to the analysis of intact Gram positive (Lactobacillus sanfranciscensis) or Gram negative (Escherichia coli) microorganisms. About fifty major membrane components (free fatty acids, mono-, di- and tri-glycerides, phospholipids, glycolipids and cardiolipins) were quickly and easily detected over a mass range spanning from ca. 200 to ca. 1600 m/z. Moreover, mass spectra with improved S/N ratio (compared to single matrices), reduced chemical noise and no formation of matrix-clusters were invariably obtained demonstrating the potential of this binary matrix to improve sensitivity.

Synthesis and Antimicrobial Activity of Copper Nanomaterials

Bioactive copper nanomaterials are an emerging class of nano-antimicrobials providing complimentary effects and characteristics, as compared to other nano-sized metals, such as silver or zinc oxide nanoparticles. In this chapter, copper nano-antimicrobials are reviewed and classified firstly as a function of the preparation methods, and secondly as a function of the target microorganism used for testing their antimicrobial activity. The antimicrobial activity of copper-based nanostructures depends on the microbial species and on the experimental set-up. As a consequence, in this chapter details are provided on methods, as well as on experimental details such as contact time, microorganism strain, concentration of the interacting species, etc. Finally, real-life applications of copper-based nanoantimicrobials are briefly discussed.

Thermally annealed gold nanoparticles for surface-assisted laser desorption ionisation-mass spectrometry of low molecular weight analytes

Metal nanomaterials have an emerging role in surface-assisted laser desorption ionisation–mass spectrometry (SALDI-MS) providing a useful tool to overcome some limitations intrinsically related to the use of conventional organic matrices in matrix-assisted LDI-MS. In this contribution, the possibility to use a stainless-steel-supported gold nanoparticle (AuNP) film as a versatile platform for SALDI-MS was assessed. A sacrificial anode electrosynthetic route was chosen in order to obtain morphologically controlled core–shell AuNPs; the colloidal AuNPs were, thereafter, drop cast onto a stainless-steel sample plate and the resulting AuNP film was thermally annealed in order to improve its effectiveness as LDI-MS promoter. Spectroscopic characterization of the nanostructured film by X-ray photoelectron spectroscopy was crucial for understanding how annealing induced changes in the surface chemistry and influenced the performance of AuNPs as desorption/ionisation promoter. In particular, it was demonstrated that the post-deposition treatments were essential to enhance the AuNP core/analyte interaction, thus resulting in SALDI-MS spectra of significantly improved quality. The AuNP films were applied to the detection of three different classes of low molecular weight (LMW) analytes, i.e. amino acids, peptides and LMW polymers, in order to demonstrate the versatility of this nanostructured material.