Optimizing Moss and Lichen Transplants as Biomonitors of Airborne Anthropogenic Microfibers.

Anthropogenic microfibers (mfs) are synthetic particles composed of cellulose (cotton, rayon, acetate, etc.) or petrochemical-based polymers (i.e., microplastics-MPs) that are less than 5 mm in length. The accumulation of mfs, including MPs, in the moss Hypnum cupressiforme and the lichen Pseudevernia furfuracea was compared in a transplant experiment lasting 6 weeks. We also tested the effects of the bag used for transplants on the accumulation of mfs. Anthropogenic particles trapped by both biomonitors were mostly filamentous (99% mfs), and their number was overall higher in the moss (mean ± s.d. 102 ± 24) than in the lichen (mean ± s.d. 87 ± 17), at parity of sample weight. On average, mfs found in lichen were significantly longer than those found in moss bags, suggesting that lichens are less efficient at retaining smaller mfs. Exposure without the net yielded a higher mfs number accumulation in both species, indicating that "naked" transplants provide greater sensitivity. The calculation of daily fluxes evidenced a loss of mfs in the lichen, suggesting the presence of more stable bonds between moss and mfs. Raman microspectroscopy carried out on about 100 debris confirms the anthropogenic nature of mfs, of which 20% were MPs. Overall results indicate that moss is preferable to lichen in the biomonitoring of airborne mfs especially when exposed naked.

The Effectiveness of Cyrene as a Solvent in Exfoliating 2D TMDs Nanosheets.

The pursuit of environmentally friendly solvents has become an essential research topic in sustainable chemistry and nanomaterial science. With the need to substitute toxic solvents in nanofabrication processes becoming more pressing, the search for alternative solvents has taken on a crucial role in this field. Additionally, the use of toxic, non-economical organic solvents, such as N-methyl-2 pyrrolidone and dimethylformamide, is not suitable for all biomedical applications, even though these solvents are often considered as the best exfoliating agents for nanomaterial fabrication. In this context, the success of producing two-dimensional transition metal dichalcogenides (2D TMDs), such as MoS2 and WS2, with excellent captivating properties is due to the ease of synthesis based on environment-friendly, benign methods with fewer toxic chemicals involved. Herein, we report for the first time on the use of cyrene as an exfoliating agent to fabricate monolayer and few-layered 2D TMDs with a versatile, less time-consuming liquid-phase exfoliation technique. This bio-derived, aprotic, green and eco-friendly solvent produced a stable, surfactant-free, concentrated 2D TMD dispersion with very interesting features, as characterized by UV-visible and Raman spectroscopies. The surface charge and morphology of the fabricated nanoflakes were analyzed using ς-potential and scanning electron microscopy. The study demonstrates that cyrene is a promising green solvent for the exfoliation of 2D TMD nanosheets with potential advantages over traditional organic solvents. The ability to produce smaller-sized-especially in the case of WS2 as compared to MoS2-and mono/few-layered nanostructures with higher negative surface charge values makes cyrene a promising candidate for various biomedical and electronic applications. Overall, the study contributes to the development of sustainable and environmentally friendly methods for the production of 2D nanomaterials for various applications.

Tunable Raman Gain in Transparent Nanostructured Glass-Ceramic Based on Ba2NaNb5O15 †.

Stimulated Raman scattering in transparent glass-ceramics (TGCs) based on bulk nucleating phase Ba2NaNb5O15 were investigated with the aim to explore the influence of micro- and nanoscale structural transformations on Raman gain. Nanostructured TGCs were synthesized, starting with 8BaO·15Na2O·27Nb2O5·50SiO2 (BaNaNS) glass, by proper nucleation and crystallization heat treatments. TGCs are composed of nanocrystals that are 10-15 nm in size, uniformly distributed in the residual glass matrix, with a crystallinity degree ranging from 30 up to 50% for samples subjected to different heat treatments. A significant Raman gain improvement for both BaNaNS glass and TGCs with respect to SiO2 glass is demonstrated, which can be clearly related to the nanostructuring process. These findings show that the nonlinear optical functionalities of TGC materials can be modulated by controlling the structural transformations at the nanoscale rather than microscale.

Combating Actions of Green 2D-Materials on Gram Positive and Negative Bacteria and Enveloped Viruses.

Interactions of novel bi-dimensional nanomaterials and live matter such as bacteria and viruses represent an extremely hot topic due to the unique properties of the innovative nanomaterials, capable in some cases to exhibit bactericide and antiviral actions. The interactions between bacteria and viruses and two dimensional nanosheets are here investigated. We extensively studied the interaction between a gram-negative bacterium, Escherichia coli, and a gram-positive bacterium, Staphylococcus aureus, with two different types of 2D nanoflakes such as MoS2, belonging to the Transition Metal Dichalcogenides family, and Graphene Oxide. The same two types of nanomaterials were employed to study their antiviral action toward the Herpes simplex virus type-1, (HSV-1). The experimental results showed different bactericide impacts as well as different antiviral power between the two nanomaterials. The experimental findings were interpreted in bacteria on the base of the Derjaguin-Landau-Verwey-Overbeek theory. A simple kinetic model of bacterial growth in the presence of the interacting nanosheets is also elaborated, to explain the observed results. The experimental results in viruses are really novel and somewhat surprising, evidencing a stronger antiviral action of Graphene Oxide as compared to MoS2. Results in viruses are complicated to quantitatively interpret due to the complexity of the system under study, constituted by virus/host cell and nanoflake, and due to the lack of a well assessed theoretical context to refer to. Thus, these results are interpreted in terms of qualitative arguments based on the chemical properties of the interactors in the given solvent medium.

Green synthesis of conductive polyaniline by Trametes versicolor laccase using a DNA template.

The green synthesis of highly conductive polyaniline by using two biological macromolecules, i.e laccase as biocatalyst, and DNA as template/dopant, was achieved in this work. Trametes versicolor laccase B (TvB) was found effective in oxidizing both aniline and its less toxic/mutagenic dimer N-phenyl-p-phenylenediamine (DANI) to conductive polyaniline. Reaction conditions for synthesis of conductive polyanilines were set-up, and structural and electrochemical properties of the two polymers were extensively investigated. When the less toxic aniline dimer was used as substrate, the polymerization reaction was faster and gave less-branched polymer. DNA was proven to work as hard template for both enzymatically synthesized polymers, conferring them a semi-ordered morphology. Moreover, DNA also acts as dopant leading to polymers with extraordinary conductive properties (∼6 S/cm). It can be envisaged that polymer properties are magnified by the concomitant action of DNA as template and dopant. Herein, the developed combination of laccase and DNA represents a breakthrough in the green synthesis of conductive materials.

Biological interactions of biocompatible and water-dispersed MoS2 nanosheets with bacteria and human cells.

Two dimensional materials beyond graphene such as MoS2 and WS2 are novel and interesting class of materials whose unique physico-chemical properties can be exploited in applications ranging from leading edge nanoelectronics to the frontiers between biomedicine and biotechnology. To unravel the potential of TMD crystals in biomedicine, control over their production through green and scalable routes in biocompatible solvents is critically important. Furthermore, considering multiple applications of eco-friendly 2D dispersions and their potential impact onto live matter, their toxicity and antimicrobial activity still remain an open issue. Herein, we focus on the current demands of 2D TMDs and produce high-quality, few-layered and defect-free MoS2 nanosheets, exfoliated and dispersed in pure water, stabilized up to three weeks. Hence, we studied the impact of this material on human cells by investigating its interactions with three cell lines: two tumoral, MCF7 (breast cancer) and U937 (leukemia), and one normal, HaCaT (epithelium). We observed novel and intriguing results, exhibiting evident cytotoxic effect induced in the tumor cell lines, absent in the normal cells in the tested conditions. The antibacterial action of MoS2 nanosheets is then investigated against a very dangerous gram negative bacterium, such as two types of Salmonellas: ATCC 14028 and wild-type Salmonella typhimurium. Additionally, concentration and layer-dependent modulation of cytotoxic effect is found both on human cells and Salmonellas.

Minimally Invasive and Portable Method for the Identification of Proteins in Ancient Paintings.

A novel method for the analysis of proteinaceous materials present on painted surfaces was developed by taking advantage of the adhesive ability of some fungal proteins which can form a stable and homogeneous layer on flexible transparency sheets able to capture trypsin in a fully active form. We demonstrated that the bioactive sheets were able to efficiently digest proteins, present as such, on surfaces of painted tests and historical samples, releasing peptides that can allow an easy and confident identification of the proteinaceous binders by standard bottom-up proteomic approach. By this method there is no need: (i) to transport the artifacts and (ii) to remove, even at micro level, a sample from the object. The ingenuity of the method lies in the easily accommodated sampling coupled with a minimal invasiveness.

Photosynthesis and mineralogy of Jania rubens at low pH/high pCO2: A future perspective.

Corallinales (Rhodophyta) are high Mg-calcite macroalgae and are considered among the most vulnerable organisms to ocean acidification (OA). These sensitive species play fundamental roles in coastal systems as food source and settlement promoters as well as being involved in reef stabilization, and water carbonate balance. At present only a few studies are focused on erect calcifying macroalgae under low pH/high pCO2 and the contrasting results make difficult to predict the ecological consequences of the OA on the coralline algae. In this paper the physiological reasons behind the resistance of Jania rubens, one of the most common calcareous species, to changing ocean pH are analysed. In particular, we studied the photosynthetic and mineralogical response of J. rubens after a three-week transplant in a natural CO2 vent system. The overall results showed that J. rubens could be able to survive under predicted pH conditions even though with a reduced fitness; nevertheless physiological limits prevent the growth and survival of the species at pH6.7. At low pH (i.e. pH7.5), the maximum and effective PSII efficiency decreased even if the increase of Rubisco expression suggests a compensation effort of the species to cope with the decreased light-driven products. In these circumstances, a pH-driven bleaching phenomenon was also observed. Even though the photosynthesis decreased at low pH, J. rubens maintained unchanged the mineralogical composition and the carbonate content in the cell wall, suggesting that the calcification process may also have a physiological relevance in addition to a structural and/or a protective role. Further studies will confirm the hypotheses on the functional and evolutionary role of the calcification process in coralline algae and on the ecological consequences of the community composition changes under high pCO2 oceans.

The characterization of natural gemstones using non-invasive FT-IR spectroscopy: New data on tourmalines.

Fourteen samples of tourmaline from the Real Museo Mineralogico of Federico II University (Naples) have been characterized through multi-methodological investigations (EMPA-WDS, SEM-EDS, LA-ICP-MS, and FT-IR spectroscopy). The samples show different size, morphology and color, and are often associated with other minerals. Data on major and minor elements allowed to identify and classify tourmalines as follows: elbaites, tsilaisite, schorl, dravites, uvites and rossmanite. Non-invasive, non-destructive FT-IR and in-situ analyses were carried out on the same samples to validate this chemically-based identification and classification. The results of this research show that a complete characterization of this mineral species, usually time-consuming and expensive, can be successfully achieved through non-destructive FT-IR technique, thus representing a reliable tool for a fast classification extremely useful to plan further analytical strategies, as well as to support gemological appraisals.

Easy entry into reduced Ar-BIANH2 compounds: a new class of quinone/hydroquinone-type redox-active couples with an easily tunable potential.

Ar-BIANH2 bearing different substituents on the aryl rings have been synthesized in high yield by reduction of the corresponding bis(aryl)acenaphthenequinonediimine (Ar-BIAN) compounds. The structure of p-CH3 C6 H4 -BIANH2 in the solid state was determined by X-ray diffraction. An exhaustive voltammetric investigation of the two parallel BIAN and BIANH2 series afforded a first rationalization of the redox properties of these molecules, highlighting their analogies with quinone/hydroquinone systems. Such analogies, in combination with the much more negative reduction potential range of Ar-BIAN compounds with respect to quinones, can afford to extend the range of reduction potentials so far obtainable by the use of quinones.

IL-6 impairs myogenic differentiation by downmodulation of p90RSK/eEF2 and mTOR/p70S6K axes, without affecting AKT activity.

IL-6 is a multifaceted pleiotropic cytokine, which is produced by a variety of cell types and targets different cells and tissues. In physiological conditions, IL-6 can be locally and transiently produced by skeletal muscle and plays an important role in muscle homeostasis. Circulating IL-6 levels are normally very low or undetectable but are dramatically increased in several pathologic conditions. In this study, we aimed to define the potential molecular mechanisms underlying the effects of IL-6 on myogenic program. We explored the molecular mechanisms through which exogenous IL-6, or the conditioned medium from the murine C-26 adenocarcinoma cells (a cellular model that secretes high levels of IL-6 and induces cancer cachexia in mice), interferes with the myogenic program. Our study revealed that IL-6 induces the activation of the Stat3 signaling and promotes the downmodulation of the p90RSK/eEF2 and mTOR/p70S6K axes, while it does not affect the activation of AKT. We thus identified potential molecular mediators of the inhibitory effects of IL-6 on myogenic program.

Age-dependent alteration in muscle regeneration: the critical role of tissue niche.

Although adult skeletal muscle is composed of fully differentiated fibers, it retains the capacity to regenerate in response to injury and to modify its contractile and metabolic properties in response to changing demands. The major role in the growth, remodeling and regeneration is played by satellite cells, a quiescent population of myogenic precursor cells that reside between the basal lamina and plasmalemma and that are rapidly activated in response to appropriate stimuli. However, in pathologic conditions or during aging, the complete regenerative program can be precluded by fibrotic tissue formation and resulting in functional impairment of the skeletal muscle. Our study, along with other studies, demonstrated that although the regenerative program can also be impaired by the limited proliferative capacity of satellite cells, this limit is not reached during normal aging, and it is more likely that the restricted muscle repair program in aging is presumably due to missing signals that usually render the damaged muscle a permissive environment for regenerative activity.

Synthesis, physicochemical properties, and preliminary biological characterizations of a novel amphoteric agmatine-based poly(amidoamine) with RGD-like repeating units.

A linear, amphoteric poly(amidoamine) nicknamed AGMA1, based on 4-aminobutylguanidine, or agmatine, was successfully prepared by Michael-type polyaddition of monoprotonated agmatine and 2,2-bis(acrylamido)acetic acid (BAC). Copolymers between AGMA1 and the biocompatible poly(amidoamine) ISA23 (deriving from the polyaddition of 2-methylpiperazine with BAC) were also prepared. Acid-base titrations gave for AGMA1 three acid dissociation constants, with pKa values of 2.25, 7.45, and >or=12.1, corresponding to a strong acid, a medium-weak base, and a strong base, respectively. The charge distribution profiles show that this polymer is prevailingly cationic at all physiological pH values, the positive net average charge per unit varying from about 0.5 at pH 7.4 to about 1.0 at pH 5, with an isoelectric point at pH approximately 10. Zeta-potential measurements confirmed this. Despite that, AGMA1 is nontoxic and nonhemolytic in vitro within all pH ranges tested (4-7.5). This is in contrast with the previously observed behavior of amphoteric PAAs, for instance ISA23, that are weakly hemolytic at pH 7.4 but highly hemolytic at pH 5/5.5. The lack of hemolytic activity of AGMA1 even at acidic pH values seems typical of the agmatine-BAC sequences and may be ascribed to their RGD-like structure. In fact, AGMA1-ISA23 copolymers behave in a way increasingly similar to that of ISA23; that is, they become hemolytic at low pH values as their ISA23 content increases.