Alessandro Buccolieri

Non-functionalized silver nanoparticles for a localized surface plasmon resonance-based glucose sensor

The optical properties of non-functionalized silver nanoparticles in ethanol solution have been analyzed and a progressive shift of localized surface plasmon resonances caused by the adding of increasing quantities of glucose has been observed. To understand this occurrence, the interaction of glucose molecules with the silver nanoparticle surface has been investigated using Raman spectroscopy. In addition, high resolution transmission electron microscopy shows the presence of superstructures on the silver nanoparticle surface that can be imputed to the presence of glucose.

Monitoring of total and bioavailable heavy metals concentration in agricultural soils

The aim of this paper is to evaluate total and bioavailable concentration of heavy metals in agricultural soils in order to estimate their distribution, to identify the possible correlations among toxic elements and the pollution sources, to distinguish the samples in relation to sampling site or to sampling depth, and to evaluate the available fraction providing information about the risky for plants. In particular, we reinvestigated total concentrations of As, Be, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, V, and Zn and available concentrations of As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, and Zn in soil from Apulia (Southern Italy). Analytical results showed that total concentrations, for all soils, are in the range permitted by regulations in force in Italy, but some soils evidence slight enrichment of Cd, Cr, Cu, Pb, and Zn. All the heavy metals in the available fraction were below the detection limits of the analytical techniques used except Cu, Ni, Pb, and Zn.

Particulate matter characterization at a coastal site in south-eastern Italy

Several samples of airborne particulate matter (PM), collected from 6th November to 6th December 2003 at a coastal site in the south-east of Italy, have been analyzed by different techniques to characterize elemental composition and morphological properties of the inorganic PM fraction and obtain preliminary results on anthropogenic contributions. Al, Cr, Cu, Fe, Mn, V, Pb, Ti, Ca and Zn mass concentrations, evaluated by an inductively coupled plasma atomic emission spectrometer, account for up to l% of the bulk PM mass in the investigated samples. According to geochemical calculations, Ca, Al, Fe and Mn are predominantly of crustal origin, while Cr, Cu, Pb, V, Ti and Zn heavy metals are of anthropogenic origin. Ion chromatography analyses have identified sulfate (SO(4)(2-)) nitrate (NO(3)(-)), sodium (Na(+)), and ammonium (NH(4)(+)) as the main ionic components accounting for up to 38% of the total PM mass and up to 90% of the total ionic mass. Besides ion chromatography, X-ray energy dispersive (EDX) microanalyses have revealed the high variability of Cl: its weight concentration varies from about 24% to below the detection limit (>or=0.5%) in the investigated samples. The marked anti-correlation between the excess of S and the Cl/Na ratio has allowed inferring that reactions between sea salt particles and acidic sulfates, which liberate HCl gas to the atmosphere leaving particles enriched in non-sea-salt sulfates, have significantly contributed to chloride depletion. Morphological analyses by scanning electron microscopy have shown that about 90% of the total sampled particles have a diameter <or=5 microm.

Synthesis and In Vitro Cytotoxicity of Glycans-Capped Silver Nanoparticles

Silver nanostructures were successfully synthesized through a simple and “green” method using saccharides as reducing and capping agent. Transmission electron microscopy (TEM) and UV–Vis absorption...

High ordered biomineralization induced by carbon nanoparticles in the sea urchin Paracentrotus lividus

A surprising and unexpected biomineralization process was observed during toxicological assessment of carbon nanoparticles on Paracentrotus lividus (sea urchin) pluteus larvae. The larvae activate a process of defense against external material, by incorporating the nanoparticles into microstructures of aragonite similarly to pearl oysters. Aiming at a better understanding of this phenomenon, the larvae were exposed to increasing concentrations of carbon nanoparticles and the biomineralization products were analyzed by electron microscopy, x-ray diffraction and Raman spectroscopy. In order to evaluate the possible influence of Sp-CyP-1 expression on this biomineralization process by larvae, analyses of gene expression (Sp-CyP-1) and calcein labeling were performed. Overall, we report experimental evidence about the capability of carbon nanoparticles to induce an increment of Sp-CyP-1 expression with the consequent activation of a biomineralization process leading to the production of a new pearl-like biomaterial never previously observed in sea urchins.

Silver and carbon nanoparticles toxicity in sea urchin Paracentrotus lividus embryos

Abstract Environment hazards and risks of engineered NanoParticles (NPs) have been debated in recent years. In this paper, the effects of silver (Ag) and carbon (C) NPs were explored in sea urchin Paracentrotus lividus (P. lividus) development. Fertilization and development of P. lividus up to the pluteus stage were assayed in the presence of increasing amounts of NPs. The embryotoxicity test performed on sea urchin P. lividus, from fertilization until the larva stage, revealed that both AgNPs and CNPs were embryotoxic since they caused embryo malformations and alteration of the normal progression through the development stages. Embryonic development was slowed down by AgNPs and sped up by CNPs. Interestingly, AgNPs-induced malformations led embryos to die in a concentration-dependent manner; while embryos bearing CNPs-induced malformations survived for a longer time.

Cytotoxicity of β-D-glucose coated silver nanoparticles on human lymphocytes

This study deals with the cytotoxicity of 30 nm sized β-D-Glucose-coated silver NanoParticles (AgNPs-G) on human lymphocytes isolated from peripheral blood. Human lymphocytes were treated with different amounts (2 or 10×103 NPs/cell) of AgNPs-G for 24hs. AgNPs-G toxicity was assayed with MTT test and morphological observations. Further evaluation included: (i) ROS generation (NBT assay) and (ii) absorption/uptake of AgNPs-G by lymphocytes (GF-AAS). As a general result, AgNPs-G were absorbed/taken up by lymphocytes and cytotoxicity and morphology changes were amount and time-dependent. By incubating cells with the highest NPs amount, only 10% viable lymphocytes were found at the end of experimental time. Parallel to cytotoxicity, morphological modifications and ROS generation were induced, thus supporting the increasing cell deaths. Interestingly, the lower amount of AgNPs-G increased cell viability as the glucose did. Our findings suggest that AgNPs-G-induced cytotoxicity depends on NPs amount and provide...

Enhanced electrical conductivity of collagen films through long-range aligned iron oxide nanoparticles

The development of biocompatible collagen substrates able to conduct electric current along specific pathways represent an appealing issue in tissue engineering, since it is well known that electrical stimuli significantly affects important cell behaviour, such as proliferation, differentiation, directional migration, and, therefore, tissue regeneration. In this work, a cheap and easy approach was proposed to produce collagen-based films exhibiting enhanced electrical conductivity, through the simple manipulation of a weak external magnetic trigger. Paramagnetic iron oxide nanoparticles (NPs) capped by a biocompatible polyethylene-glycol coating were synthetized by a co-precipitation and solvothermic method and sprayed onto a collagen suspension. The system was then subjected to a static external magnetic field in order to conveniently tune NPs organization. Under the action of the external stimulus, NPs were induced to orient along the magnetic field lines, forming long-range aligned micropatterns within the collagen matrix. Drying of the substrate following water evaporation permanently blocked the magnetic architecture produced, thereby preserving NPs organization even after magnetic field removal. Electrical conductivity measurements clearly showed that the presence of such a magnetic framework endowed collagen with marked conductive properties in specific directions. The biocompatibility of the paramagnetic collagen films was also demonstrated by MTT cell cytotoxicity test.

Solid-to-solid phase transformations of nanostructured selenium-tin thin films induced by thermal annealing in oxygen atmosphere

The structural and morphological evolution of nanostructured thin films obtained from thermal evaporation of polycrystalline Sn-Se starting charge as a function of the subsequent annealing temperature in an oxygen flow has been analysed. High-resolution transmission electron microscopy, small area electron diffraction, digital image processing, x-ray diffraction and Raman spectroscopy have been employed in order to investigate the structure and the morphology of the obtained films. The results evidenced, in the temperature range from RT to 500°C, the transition of the material from a homogeneous mixture of SnSe and SnSe2 nanocrystals, towards a homogeneous mixture of SnO2 and SeO2 nanocrystals, with an intermediate stage in which only SnSe2 nanocrystals are present.

Laser ablation threshold of cultural heritage metals

In this work we determined experimentally the threshold fluence of the most common metals found in cultural heritage, e.g. copper, silver and their alloys. We carried out the ablation process in air at atmospheric pressure with 8 ns pulsed Nd:YAG and 23 ns pulsed KrF lasers, at 532 and 248 nm, respectively. We irradiated every target by a fixed number of laser shots (repetition rate of 1 Hz) at several laser fluence values. Then, the resulting craters were characterized by a stylus surface profiler in order to obtain the dependence of ablation rate on laser fluence F. Here, we defined the ablation raate as ablated matter thickness for single laser pulse, x. Therefore, we identified the ablation threshold fluence, Fth, as the fluence value below which no ablation process would occur.