Search

Metal halide perovskites are set to revolutionise photovoltaic energy harvesting owing to an unmatched combination of high efficiency and low fabrication costs. However, to improve the sustainability of this technology, replacing lead with less toxic tin is highly desired. Tin halide perovskites are approaching 15 in power conversion efficiency PCE , mainly employing PEDOT PSS as a hole selective layer. Unfortunately, PEDOT PSS is processed from an aqueous solution, which is hardly compatible with the strict anoxic requirements for processing tin halide perovskites due to tin s instability to oxidation. Here, we present a water free PEDOT formulation for developing tin based lead free perovskite solar cells. We show that the main difference between the PCE of devices made from aqueous and water free PEDOT is due to the marked hydrophobicity of the latter, which complicates the perovskite deposition. By modifying the surface of water free PEDOT with a thin Al2O3 interlayer, we could achieve good perovskite morphology that enabled perovskite solar cells with a PCE of 7.5

Alessandro Paolini,1 Giulia Battafarano,1 Valentina D’Oria,1 Francesco Mura,2 Simona Sennato,3 Valentina Mussi,4 Roberta Risoluti,5 Stefano Materazzi,5 Andrea Del Fattore,1 Andrea Masotti1 1Bambino Gesù Children’s Hospital, IRCCS, Research Laboratories, Rome 00146, Italy; 2Center for Nanotechnology for Engineering (CNIS), Sapienza University of Rome, Rome 00185, Italy; 3CNR-ISC UOS Sapienza and Physics Department, Sapienza University of Rome, Rome 00185, Italy; 4National Research Council, Institute for Microelectronics and Microsystems IMM-CNR, Roma 00133, Italy; 5Department of Chemistry, Sapienza University of Rome, Rome 00185, ItalyCorrespondence: Andrea MasottiBambino Gesù Children’s Hospital, IRCCS, Research Laboratories, Gene Expression-Microarrays Laboratory, Viale di San Paolo 15, Rome 00146, ItalyTel +39-06-68592650Fax +39-0668592904Email andrea.masotti@opbg.netBackground: The advent of 3D printing technology allowed the realization of custom devices that can be used not only in the everyday life but also in the nanotechnology and biomedical fields. In nanotechnology, the use of bi-dimensional nanostructures based on carbon nanotubes, generally referred as buckypapers, have received considerable attention for their versatility and potential application in many biomedical fields. Unfortunately, buckypapers are extremely hydrophobic and cannot be used in aqueous media to culture cells.Methods: A polymeric device able to accommodate buckypapers and facilitate cell growth was fabricated by using 3D printing technology. We imparted hydrophilicity to buckypapers by coating them with polyamidoamine (PAMAM) dendrimers.Results: We found that by using novel techniques such as polymer coating the buckypaper hydrophilicity increased, whereas the use of 3D printing technology allowed us to obtain custom devices that have been used to culture cells on buckypapers for many days. We characterized in details the morphology of these structures and studied for the first time the kinetic of cell proliferation. We found that these scaffolds, if properly functionalized, are suitable materials to grow cells for long time and potentially employable in the biomedical field.Conclusion: Although these materials are cytotoxic under certain circumstances, we have found a suitable coating and specific experimental conditions that encourage using buckypapers as novel scaffolds for cell growth and for potential applications in tissue repair and regeneration.Keywords: 3D printing, buckypaper, PAMAM dendrimer, cell proliferation, tissue regeneration, transfection

A number of policy measures have been adopted to cope with ongoing ocean degradation. Marine protected areas (MPAs) are among them. MPAs and their coverage have increased worldwide, including in EU waters. Natura 2000 (Nat2000) sites are at the core of the EU biodiversity conservation strategy and have been established to protect habitats and species included in two EU directives. Besides their specific objectives, their potential to contribute to an ecosystem-wide conservation and their complementarity with other national and supranational initiatives (e.g. nationally established MPA networks, the Marine Strategy Framework Directive, the Convention on Biological Diversity Ecosystem-Based Approach) have been called into question. Using visual censuses on rocky reefs, the biomass of whole fish assemblages and of a set of ecologically important species (widely used as indicators of coastal marine ecosystem health) have been assessed to evaluate the potential ecosystem-wide effectiveness of Nat2000 marine sites located along the coasts of Sardinia (Italy). The assessment was performed in six fully protected MPAs, in 12 Nat2000 sites established or extending at sea, and in 18 adjacent unprotected control sites. Results show that the highest fish biomasses are observed in fully protected MPAs. The values observed at Nat2000 sites do not differ or only slightly differ from those observed at control sites. This shows that Nat2000 sites may not presently contribute to effectively protect fish and the related rocky reef ecosystems. These results do not dismiss at all the role of Nat2000 sites relative to the objectives for which they have been established. However, they show that to achieve ecosystem-wide benefits it is crucial to rethink and broaden the scope of Nat2000 sites and adapt their management to that. By providing sounder and more comprehensive management plans, and implementing more consistent ecosystem-wide conservation measures, Nat2000 marine sites could become an extraordinary tool at the EU scale, capable of delivering wider ecological benefits.

The moonmilk is a secondary calcite deposit (speleothem) formed by nanofibers of calcite and commonly found in karst caves. While its biogenic origin is widely accepted, the mechanism of calcite nanofibers production remains unclear. Crystallization and formation mechanism of calcium carbonate nanostructures are of high interest in different fields, such as geomicrobiology (rock-microbes interactions), astrobiology (biosignatures), medicine (antibiotics producing bacteria), nanotechnology (calcium carbonate nanofibers) and recently, archeology. The discovery of the moonmilk in the hypogeal tombs of the ancient necropolis of Tarquinia (Italy), provides a unique opportunity to compare moonmilk crystal shapes that originated from two type of rocks, Macco (a calcarenite) and Sabbione (a hybrid sandstone). We analyzed, through a SEM analysis, moonmilk samples from twelve tombs in the necropolis area and found that rocks provide an ideal environment for the formation of the nanofibers; the Sabbione promoted the growth of a finer and thinner carbonate nanostructures, probably due to a slower growth kinetics caused by a low calcium value present in this rock.

Exosome-like nanoparticles (ELNs) are attracting interest as important vehicles of intercellular communication, both in prokaryotes and eukaryotes. Recently, dietary nanoparticles similar to mammalian exosomes have attracted attention for these features. In particular they appear to be relevant in the modulation of several cellular processes as well as candidate carriers of bioactive molecules (proteins, lipids, and nucleic acids, including miRNAs) with therapeutic value. Herein, we investigated the cellular uptake of blueberry-derived ELNs (B-ELNs) by a human stabilized endothelial cell line (EA.hy926) and the ability of B-ELNs to modulate the expression of inflammatory genes as the response of tumor necrosis factor-&alpha, (TNF-&alpha, ). Our results indicate that 1) EA.hy926 cells internalize B-ELNs in a dose-dependent manner, 2) pretreatment with B-ELNs counters TNF-&alpha, induced reactive oxygen species (ROS) generation and loss of cell viability and modulates the differential expression of 29 genes (fold change &gt, 1.5) induced by TNF-&alpha, compared to control, 3) pathway analysis reveals their involvement in a total of 340 canonical pathways, 121 KEGG pathways, and 121 GO Biological processes, and 4) the intersection between differentially expressed (DE) genes and miRNAs contained in B-ELNs unveils a set of candidate target genes, such as prostaglandin I2 synthase (PTGIS), mitogen-activated protein kinase 14 (MAPK14), and phosphodiesterase 7A (PDE7A), for ELNs-contained cargo. In conclusion, our study indicates that B-ELNs can be considered candidate therapeutic carriers of bioactive compounds potentially able to protect vascular system against various stressors.

Earth's microbial biosphere extends down through the crust and much of the subsurface, including those microbial ecosystems located within cave systems. Here, we elucidate the microbial ecosystems within anthropogenic 'caves'; the Iron-Age, subterranean tombs of central Italy. The interior walls of the rock (calcium-rich macco) were painted ~2500 years ago and are covered with CaCO3 needles (known as moonmilk). The aims of the current study were to: identify biological/geochemical/biophysical determinants of and characterize bacterial communities involved in CaCO3 precipitation; challenge the maxim that biogenic activity necessarily degrades surfaces; locate the bacterial cells that are the source of the CaCO3 precipitate; and gain insight into the kinetics of moonmilk formation. We reveal that this environment hosts communities that consist primarily of bacteria that are mesophilic for temperature and xerotolerance (including Actinobacteria, Bacteroidetes and Proteobacteria); is populated by photosynthetic Cyanobacteria exhibiting heterotrophic nutrition (Calothrix and Chroococcidiopsis); and has CaCO3 precipitating on the rock surfaces (confirmation that this process is biogenic) that acts to preserve rather than damage the painted surface. We also identified that some community members are psychrotolerant (Polaromonas), acidotolerant or acidophilic (members of the Acidobacteria), or resistant to ionizing radiation (Brevundimonas and Truepera); elucidate the ways in which microbiology impacts mineralogy and vice versa; and reveal that biogenic formation of moonmilk can occur rapidly, that is, over a period of 10 to 56 years. We discuss the paradox that these ecosystems, that are for the most part in the dark and lack primary production, are apparently highly active, biodiverse and biomass-rich.

Few works have addressed the effects provoked by the exposure to cadmium containing nanoparticles (NPs) on adult zebrafish (Danio rerio). We studied the effects of CdS NPs (5 nm) or ionic cadmium (10 μg Cd/L) after 3 and 21 d of exposure and at 6 months post-exposure (mpe). Acute toxicity was recorded after exposure to both forms of cadmium. Significant cadmium accumulation was measured in the whole fish after both treatments and autometallography showed a higher accumulation of metal in the intestine than that in the liver. Histopathological alterations, such as inflammation in gills and vacuolization in the liver, were detected after the exposure to both cadmium forms and, in a lower extent, at 6 mpe. X-ray analysis proved the presence of CdS NPs in these organs. The hepatic transcriptome analysis revealed that gene ontology terms such as “immune response” or “actin binding” were over-represented after 21 d of exposure to ionic cadmium respect to CdS NPs treatment. Exposure to CdS NPs caused a significant effect on pathways involved in the immune response and oxidative stress, while the exposure to ionic cadmium affected significantly pathways involved in DNA damage and repair and in the energetic metabolism. Oxidative damage to liver proteins was detected after the exposure to ionic cadmium, while a stronger destabilization of the hepatocyte lysosomal membrane was recorded under exposure to CdS NPs. In summary, although ionic cadmium provoked stronger effects than CdS NPs, both cadmium forms exerted an array of lethal and sublethal effects to zebrafish.

In this work, we have analyzed and characterized a white patina, that covers the walls and frescoes of two Etruscan tombs located in the Monterozzi's necropolis of Tarquinia: the Tomba degli Scudi and the Tomba Bartoccini. The powders have been retrieved from these areas before and during the intervention of the restorers and then SEM\EDX, FT-IR and XRD have been performed for the characterization. These white powders are formed by rod-like and crystalline calcium carbonate, the length of which is a few micrometers, while the thickness has an average value of about 400 nm. This particular structure can be traced back to the moonmilk, a particular form of calcium carbonate, normally found in karst caves or other underground environments. Besides, the presence of some microorganisms in close connection with this material provides an important clue of its biological origin.

Effects of silver nanoparticles (Ag NPs) on freshwater species have been reported in several studies, but there is not information on the potential long-term consequences of a previous exposure. In this work, we investigated the long-term effects of maltose-coated Ag NPs (20 nm) and of ionic silver (10 μg/L) after 21 days of exposure and at 6 months post-exposure (mpe) in adult zebrafish. Exposure resulted in significant silver accumulation in the whole body of fish exposed to ionic silver, but not in those exposed to Ag NPs. However, autometallography revealed metal accumulation in the liver and intestine of fish treated with the two silver forms and especially in the intestine of fish exposed to Ag NPs. X-ray microanalysis showed the presence of silver in gills, liver and intestine and of Ag NPs in gill and liver cells. Inflammation and hyperplasia were evident in the gills after both treatments and these histopathological conditions remained at 6 mpe. According to the hepatic transcriptome analysis, at 3 days ionic silver regulated a larger number of transcripts (410) than Ag NPs (129), while at 21 days Ag NPs provoked a stronger effect (799 vs 165 regulated sequences). Gene ontology terms such as “metabolic processes” and “response to stimulus” appeared enriched after all treatments, while “immune system” or “reproductive processes” were specifically enriched after the exposure to Ag NPs. This suggests that the toxicity of Ag NPs may not be solely related to the release of Ag ions, but also to the NP form. No evident effects were found on protein oxidation or on hepatocyte lysosomal membrane stability during exposure, but effects recorded on liver lysosomes and persistent damage on gill tissue at 6 mpe could indicate potential for long-term effects in exposed fish.

Self-assembled structures formed by mixtures of cationic and anionic surfactants are interesting tools for applications requiring interactions with charged particles and molecules. Nevertheless, they present instability close to the equimolar composition and poor morphological versatility, which is generally restricted to vesicles and micelles. Against this general trend, we report on bile salt derivative based catanionic mixtures assembling in tubules and lamellae depending on the mixture composition. Electrophoretic mobility measurements prove that the composition also dictates their superficial charge, which can be tuned from negative to positive by increasing the positively charged surfactant fraction in the mixtures. The study of the catanionic aggregates was conducted by means of microscopy and spectroscopy techniques and compared to the self-assembly behaviors of the individual building blocks. This study broadens the so far small array of bile salt derivative catanionic systems, confirming their distinctive behavior in the spectrum of catanionic mixtures.

One hour annealing at 300 °C changes the optical emission characteristics of InAs nanowires (NWs) from the wurtzite (WZ) phase into that of zincblende (ZB). These results are accounted for by the conversion of a small fraction of the NW WZ metastable structure into the stable ZB structure. Several paths toward the polytype transformation in the configuration space are also demonstrated using first-principles calculations. For lower annealing temperatures, emission which is likely related to WZ polytypes is observed at energies that agree with theoretical predictions. These results demonstrate severe constraints on thermal processes to which devices made from InAs WZ NWs can be exposed.

This study aims to determine the interaction (uptake and biological effects on cell viability and cell cycle progression) of glucose capped silver nanoparticles (AgNPs-G) on human epithelioid cervix carcinoma (HeLa) cells, in relation to amount, 2 × 10 3 or 2 × 10 4 NPs/cell, and exposure time, up to 48 h. The spherical and well dispersed AgNPs (30 ± 5 nm) were obtained by using glucose as reducing agent in a green synthesis method that ensures to stabilize AgNPs avoiding cytotoxic soluble silver ions Ag + release. HeLa cells take up abundantly and rapidly AgNPs-G resulting toxic to cells in amount and incubation time dependent manner. HeLa cells were arrested at S and G2/M phases of the cell cycle and subG1 population increased when incubated with 2 × 10 4 AgNPs-G/cell. Mitotic index decreased accordingly. The dissolution experiments demonstrated that the observed effects were due only to AgNPs-G since glucose capping prevents Ag + release. The AgNPs-G influence on HeLa cells viability and cell cycle progression suggest that AgNPs-G, alone or in combination with chemotherapeutics, may be exploited for the development of novel antiproliferative treatment in cancer therapy. However, the possible influence of the cell cycle on cellular uptake of AgNPs-G and the mechanism of AgNPs entry in cells need further investigation.

In Crohn&rsquo, s disease (CD) patients, intestinal dysbiosis with an overgrowth of Proteobacteria, mainly Escherichia coli, has been reported. A new pathotype of E. coli, the adherent-invasive Escherichia coli strain (AIEC), has been isolated from the mucosae of CD patients. AIEC strains play an important role in CD pathogenesis, increasing intestinal mucosa damage and inflammation. Several studies have been undertaken to find possible strategies/treatments aimed at AIEC strain reduction/elimination from CD patients&rsquo, intestinal mucosae. To date, a truly effective strategy against AIEC overgrowth is not yet available, and as such, further investigations are warranted. Bdellovibrio bacteriovorus is a predator bacterium which lives by invading Gram-negative bacteria, and is usually present both in natural and human ecosystems. The aim of this study was to evaluate a novel possible strategy to treat CD patients&rsquo, mucosae when colonized by AIEC strains, based on the utilization of the Gram-negative predatory bacteria, B. bacteriovorus. The overall results indicate that B. bacteriovorus is able to interfere with important steps in the dynamics of pathogenicity of AIEC strains by its predatory activity. We indicate, for the first time, the possibility of counteracting AIEC strain overgrowth by exploiting what naturally occurs in microbial ecosystems (i.e., predation).

InAs nanowires (NWs) have been grown on semi-insulating InAs (111)B substrates by metal-organic chemical vapor deposition catalyzed by 50, 100, and 150 nm-sized Au particles. The pure wurtzite (WZ) phase of these NWs has been attested by high-resolution transmission electron microscopy and selected area diffraction pattern measurements. Low temperature photoluminescence measurements have provided unambiguous and robust evidence of a well resolved, isolated peak at 0.477 eV, namely 59 meV higher than the band gap of ZB InAs. The WZ nature of this energy band has been demonstrated by high values of the polarization degree, measured in ensembles of NWs both as-grown and mechanically transferred onto Si and GaAs substrates, in agreement with the polarization selection rules for WZ crystals. The value of 0.477 eV found here for the bandgap energy of WZ InAs agrees well with theoretical calculations.

Coupling graphene with a soft polymer surface offers the possibility to build hybrid constructs with new electrical, optical, and mechanical properties. However, the low reactivity of graphene is a hurdle in the synthesis of such systems which is often bypassed by oxidizing its carbon planar structure. However, the defects introduced with this process jeopardize the properties of graphene. In this paper we present a different approach, applicable to many different polymer surfaces, which uses surfactant assisted ultrasonication to exfoliate, and simultaneously suspend, graphene in water in its intact form. Tethering pristine graphene sheets to the surfaces is accomplished by using suitable reactive functional groups of the surfactant scaffold. We focused on applying this approach to the fabrication of a hybrid system, made of pristine graphene tethered to poly(vinyl alcohol) based microbubbles (PVA MBs), designed for enhancing photoacoustic signals. Photoacoustic imaging (PAI) is a powerful preclinical diagnostic tool which provides real time images at a resolution of 40 μm. The leap toward clinical imaging has so far been hindered by the limited tissues penetration of near-infrared (NIR) pulsed laser radiation. Many academic and industrial research laboratories have met this challenge by designing devices, each with pros and cons, to enhance the photoacoustic (PA) signal. The major advantages of the hybrid graphene/PVA MBs construct, however, are (i) the preservation of graphene properties, (ii) biocompatibility, a consequence of the robust anchoring of pristine graphene to the bioinert surface of the PVA bubble, and (iii) a very good enhancement in a NIR spectral region of the PA signal, which does not overlap with the signals of PA active endogenous molecules such as hemoglobin.

Heat management mechanisms play a pivotal role in driving the design of nanowire (NW)-based devices. In particular, the rate at which charge carriers cool down after an external excitation is crucial for the efficiency of solar cells, lasers, and high-speed transistors. Here, we investigate the thermalization properties of photo-generated carriers by continuous-wave (cw) photoluminescence (PL) in InP and GaAs NWs. A quantitative analysis of the PL spectra recorded up to 310 K shows that carriers can thermalize at a temperature much higher than that of the lattice. We find that the mismatch between carrier and lattice temperature, T, increases exponentially with lattice temperature and depends inversely on the NW diameter. T is instead independent of other2 NW characteristics, such as crystal structure (wurtzite vs zincblende), chemical composition (InP vs GaAs), shape (tapered vs columnar NWs), and growth method (vapor-liquid-solid vs selective-area growth). Remarkably, carrier temperatures as high as 500 K are reached at the lattice temperature of 310 K in NWs with ~70 nm diameter. While a population of non-equilibrium carriers, usually referred to as “hot carriers”, is routinely generated by high-power laser pulses and detected by ultrafast spectroscopy, it is quite remarkable that it can be observed in cw PL measurements, when a steady-state population of carriers is established. Time-resolved PL measurements show that even in the thinnest NWs carriers have enough time (~1 ns) after photo-excitation to interact with phonons and thus to release their excess energy. Nevertheless, the inability of carriers to reach a full thermal equilibrium with the lattice points to inhibited phonon emission primarily caused by the large surface-to-volume ratio of small diameter NWs.

Recent progresses in nanotechnology and their application to biomedical settings have generated great advantages in dealing with early cancer diagnosis. The identification of specific properties of cancer cells, such as the expression of particular plasma membrane molecular receptors, has become crucial in revealing the presence and in assessing the stage of development of the disease. Here we report on a single cell screening approach based on Surface Enhanced Raman Scattering (SERS) microimaging. We fabricated a SERS-labelled nanovector based on the biofunctionalization of gold nanoparticles with folic acid. After treating the cells with the nanovector, we were able to distinguish three different cell populations from different cell lines (cancer HeLa and PC-3, and normal HaCaT lines), properly chosen for their different expression of folate binding proteins. The nanovector, indeed, binds much more efficiently on cancer cell lines than on normal ones, resulting in a higher SERS signal measured on cancer cells. These results pave the way for applications in single cell diagnostics and, potentially, in theranostics.

A white deposit covering the walls in the Stanza degli Scudi of the Tomba degli Scudi, Tarquinia, Italy, has been investigated. In this chamber, which is still preserved from any kind of intervention such as cleaning and sanitization, ancient Etruscans painted shields to celebrate the military power of the Velcha family. Scanning electron microscopy analysis has revealed the presence of characteristic nanostructures corresponding to a calcite secondary mineral deposit called moonmilk. Analysis of the microbial community identified Proteobacteria, Acidobacteria and Actinobacteria as the most common phyla in strong association with the moonmilk needle fibre calcite and nanofibers of calcium carbonate. Employing classical microbiological analysis, we isolated from moonmilk a Streptomyces strain able to deposit gypsum and calcium carbonate on plates, supporting the hypothesis of an essential contribution of microorganisms to the formation of moonmilk.

This paper presents the first prototype of a new concept nanogripper whose overall size has been reduced as much as permitted by a new fabrication process based on Nano Technology. The jaws lumen size is adequate to the mechanical manipulation of microorganisms colonies.

Many advanced synthetic, natural, degradable or non-degradable materials have been employed to create scaffolds for cell culture for biomedical or tissue engineering applications. One of the most versatile material is poly-lactide (PLA), commonly used as 3D printing filament. Manufacturing of multifunctional scaffolds with improved cell growth proliferation and able to deliver oligonucleotides represents an innovative strategy for controlled and localized gene modulation that hold great promise and could increase the number of applications in biomedicine. Here we report for the first time the synthesis of a novel Rhodamine derivative of a poly-amidoamine dendrimer (G = 5) able to transfect cells and to be monitored by confocal microscopy that we also employed to coat a 3D-printed PLA scaffold. The coating do not modify the oligonucleotide binding ability, toxicity or transfection properties of the scaffold that is able to increase cell proliferation and deliver miRNA mimics (i.e., pre-mir-503) into human cells. Although further experiments are required to optimize the dendrimer/miRNA ratio and improve transfection efficiency, we demonstrated the effectiveness of this promising and innovative 3D-printed transfection system to transfer miRNAs into human cells for future biomedical applications.

Tesi di Laurea Magistrale in Scienze Chimiche di Francesco Mura

The Tell es-Sultan, ancient Jericho, is amongst the earliest “cities” that rose in the Southern Levant between the end of 4th and the beginning of the 3rd millennium BCE. The site is being excavate...

Medicine, food, and cosmetics represent the new promising applications for silver (Ag) and gold (Au) nanoparticles (NPs). AgNPs are most commonly used in food and cosmetics; conversely, the main applications of gold NPs (AuNPs) are in the medical field. Thus, in view of the risk of accidentally or non-intended uptake of NPs deriving from the use of cosmetics, drugs, and food, the study of NPs–cell interactions represents a key question that puzzles researchers in both the nanomedicine and nanotoxicology fields. The response of cells starts when the NPs bind to the cell surface or when they are internalized. The amount and modality of their uptake depend on many and diverse parameters, such as NPs and cell types. Here, we discuss the state of the art of the knowledge and the uncertainties regarding the biological consequences of AgNPs and AuNPs, focusing on NPs cell uptake, location, and translocation. Finally, a section will be dedicated to the most currently available methods for qualitative and quantitative analysis of intracellular transport of metal NPs.

Based on atomic force microscopy (AFM), contact resonance AFM (CR-AFM) is a nondestructive technique that allows one to perform single point measurements as well as surface mapping of the indentation modulus of a material. In this work we exploit the possibility to use CR-AFM to study synthetic materials representative of K-basalt from Roman comagmatic Province. Having observed the presence of subsurface voids and inclusions at micrometer and sub-micrometer scale, a preliminary study has been conducted to verify the capability of CR-AFM nanomechanical mapping to nondestructively detect these features.