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Organic materials are widely employed to tune surface chemistry and/or as structuring agents of inorganic materials. Here, we propose a novel synthesis approach whereby TiO2 not only promotes 5,6-dihydroxyindole-2-carboxylic acid (DHICA) polymerization but also acts as a templating agent for the formation itself. Hybrid TiO2–DHICA melanin nanostructures have been produced, showing biocide activity even under visible light conditions (activation). Hybrid nanostructures have been analyzed and characterized by multiple techniques, proving that both organic and inorganic phases strongly affect each other during in situ formation, as far as it concerns both morphology and microstructure, conferring unique biocide properties to the resulting nanomaterials. This strategy ensures much more far-reaching implementation in the synthesis of hybrid nanosystems, opening new perspectives in the design of multifunctional materials. [ABSTRACT FROM AUTHOR]

Glycerol is the main by-product of biodiesel production; its upgrading to more valuable products is a demanding issue. Hydrogenolysis to 1,2-propanediol is one of the most interesting processes among the possible upgrading routes. In this study, we propose novel copper/zirconia catalysts prepared by advanced preparation methods, including copper deposition via metal–organic framework (MOF) and support preparation via the sol–gel route. The catalysts were characterized by N2 physisorption, X-ray diffraction, Scanning Electron Microscopy, H2-TPR and NH3-TPD analyses and tested in a commercial batch reactor. The catalyst prepared by copper deposition via MOF decomposition onto commercial zirconia showed the best catalytic performance, reaching 75% yield. The improved catalytic performance was assigned to a proper combination of redox and acid properties. In particular, a non-negligible fraction of cuprous oxide and of weak acid sites seems fundamental to preferentially activate the selective pathway. In particular, these features avoid the overhydrogenolysis of 1,2-propanediol to 1-propanol and enhance glycerol dehydration to hydroxyacetone and the successive hydrogenation of hydroxyacetone to 1,2-propanediol. [ABSTRACT FROM AUTHOR]

[Display omitted] • A green synthetic route leads to light-triggered redox-active melanin biointerfaces. • Post-reduction with ascorbic acid improves the radical scavenging activity. • Post-reduction with ascorbic acid increases the colloidal stability. • IR and UV light irradiation activates production of ROS. • ROS generation is quenched after redox exchange with ascorbic acid. Redox-active nanomaterials represent powerful tools for therapeutics due to either antioxidant or pro-oxidant behavior that is essential in regulating the reactive oxygen species (ROS) levels in the biological systems. A promising way to design and realize bioinspired versatile redox-active nanoplatforms is offered by melanin polymers, which are widely available hydrophobic pigments made of poly(hydroxy indole) planar structures produced by oxidative polymerization of the monomeric precursors. Melanins can radically change the redox activity as a response to external stimuli such as acidification or light irradiation, thus exhibiting ROS-generating ability. Herein, the design of versatile light-triggered redox-active melanin-based nanoplatforms is proposed through a green photocatalytic/solvothermal approach. Extensive physicochemical characterization and radical scavenging assays are conducted to define the main properties of such nanomaterials. They exert a significant paramagnetic behavior together with a strong radical scavenging activity benefitting from post-reduction with ascorbic acid, due to increase in the colloidal stability at high concentrations. ROS generation by 2D melanin-based biointerfaces obtained by depositing thin layers on glass slides is activated by IR and UV light irradiation but quenched after redox exchange with ascorbic acid. This study contributes to the future development of sustainable light-responsive bioelectronic devices. [ABSTRACT FROM AUTHOR]

TiO 2 nanoparticles loaded with pistachio shell lignin (8 % and 29 % w /w) were prepared by a hydrothermal wet chemistry approach. The efficient interaction at the molecular level of the biomacromolecule and inorganic component was demonstrated by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–Visible (UV–Vis), Fourier transform infrared (FT-IR), dynamic light scattering (DLS), and electron paramagnetic resonance (EPR) analysis. The synergistic combination of lignin and TiO 2 nanoparticles played a key role in the functional properties of the hybrid material, which exhibited boosted features compared to the separate organic and inorganic phase. In particular, the hybrid TiO 2 -lignin nanoparticles showed a broader UV–Vis protection range and remarkable antioxidant performance in aqueous media. They could also better protect human skin explants from the DNA damaging effect of UV radiations compared to TiO 2 as indicated by lower levels of p-H2A.X, a marker of DNA damage, at 6 h from exposure. In addition, the samples could protect the skin against the structural damage occurring 24 h post UV radiations by preventing the loss of keratin 10. These results open new perspectives in the exploitation of food-waste derived phenolic polymers for the design of efficient antioxidant materials for skin photoprotection in a circular economy perspective. • Hybrid TiO 2 nanostructures containing lignin as organic counterpart were prepared. • An efficient interaction of lignin and TiO 2 at the molecular level was demonstrated. • The final hybrid materials showed a broader UV-Vis protection range. • The final hybrid materials exhibited also remarkable antioxidant properties. • The hybrid materials could efficiently inhibit DNA damaging effects of UV radiations. [ABSTRACT FROM AUTHOR]

Pyro-electrohydrodynamic jetting (p-jet) has emerged recently as a promising technique for biosensing applications, through the concentration of highly diluted biomolecules in fluorescent spots at microscale. However, a great challenge still remains in optimizing the binding strategy for the sensing interface, enabling the detection of low abundance proteins through immunofluorescence protocols. Indeed, the surface of reaction can be functionalized with different chemical groups able to bind the target molecule with a strong interaction, prior to the p-jet spots decreasing the possibility to lose sensitivity after the common rinsing steps. Here, we characterize the immobilization of a model protein, specifically the bovine serum albumin (BSA), in the concentrated p-jet spots to demonstrate the reliability of the technique for highly sensitive immunodetection assays. We first performed spectroscopic measurements on BSA deposited through pipette spots at relatively high concentrations and we achieved a higher efficiency in case of the covalent bond by using the carbonate buffer and the epoxy-based slides. We then tested the covalent setting in case of the p-jet spots with highly diluted samples of pre-labelled BSA. A significant concentration-dependent behavior of the signal was obtained down to picogram levels. Finally, an immunofluorescent protocol was settled with the p-jet spots and a Limit of the Detection (LOD) of 0. 27 pg/mL was reached. The demonstration here that the p-jet spots are compatible with immunodetection procedures and provide a LOD down to 0.27 pg/mL, launches the p-jet technique towards the development in future of a point-of-care (POC) diagnostic tool. This would become a major force in analytical chemical laboratories. The identification of highly diluted biomarkers from peripheral body fluids would help clinicians performing early diagnosis, overcoming the limitations of the traditional immunochemistry tests, such as the enzyme-linked immunosorbent assay (ELISA). [Display omitted] • p-jet can concentrate highly diluted biomolecules in fluorescent spots at microscale. • The detection limit is enhanced optimizing the chemical deposition of proteins. • BSA is used as proof of concept to demonstrate the reliability of the technique. • Our revolutionary biosensor could revolutionize point-of-care (POC) diagnostics. [ABSTRACT FROM AUTHOR]

It is largely documented that neurodegenerative diseases can be effectively treated only if early diagnosed. In this context, the structural changes of some biomolecules such as Tau, seem to play a key role in neurodegeneration mechanism becoming eligible targets for an early diagnosis. Post-translational modifications are responsible to drive the Tau protein towards a transition phase from a native disorder conformation into a preaggregation state, which then straight recruits the final fibrillization process. Here, we show for the first time the detection of pre-aggregated Tau in artificial urine at femto-molar level, through the concentration effect of the pyro-electrohydrodynamic jet (p-jet) technique. An excellent linear calibration curve is demonstrated at the femto-molar level with a limit of detection (LOD) of 130 fM. Moreover, for the first time we show here the structure stability of the protein after p-jet application through a deep spectroscopic investigation. Thanks to the small volumes required and the relatively compact and cost-effective characteristics, this technique represents an innovative breakthrough in monitoring the early stage associated to neurodegeneration syndromes in different scenarios of point of care (POC) and such as for example in long-term human space exploration missions. The mechanisms of Tau protein aggregation are based on a transition phase that can be very useful in the field of neurodegeneration disorder for early diagnosis applications. Here we show an innovative strategy for detecting the initial transition phase of the Tau protein in highly diluted samples of urine, by using the concentration effect of the p-jet technique. [Display omitted] [ABSTRACT FROM AUTHOR]

• Thermal investigation of flammable dusts. • Synergistic behaviour of dust mixtures. • Novel safety classification of dust mixtures. In this work the flammable/explosive behavior of mixtures of flammable dusts is investigated. In particular, minimum ignition temperature, minimum ignition energy, maximum pressure and deflagration index have been measured at varying the relative content of dusts in the mixtures. The thermal behavior of these mixtures has been also studied by means of DSC analysis coupled to chemical analysis performed by HPLC and ATR-FTIR. Depending on the mixtures, a synergistic behavior has been found due to physical and/or chemical reactions. For some mixtures, the more severe behavior has been attributed to the presence of a eutectic point (niacin/anthraquinone, ascorbic acid/niacin), in other cases, to chemical reactions with the formation of volatiles (ascorbic acid/irganox 1222, ascorbic acid/glucose). On this basis, we propose a new classification of dusts mixtures in three mixtures safety classes (MSC): MSC 0 (no synergistic effect, ideal behavior); MSC 1 (deviation from ideality, safety parameters included between those of the pure dusts) and MSC 2 (at least 1 parameter with more sever value than those of pure dusts). [ABSTRACT FROM AUTHOR]

Sustainable active food packaging is essential to reduce the use of plastics, preserve food quality and minimize the environmental impact. Humic substances (HS) are rich in redox-active compounds, such as quinones, phenols, carboxyl, and hydroxyl moieties, making them functional additives for biopolymeric matrices, such as poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV). Herein, composites made by incorporating different amounts of HS into PHBV were developed using the electrospinning technology and converted into homogeneous and continuous films by a thermal post-treatment to obtain a bioactive and biodegradable layer which could be part of a multilayer food packaging solution. The morphology, thermal, optical, mechanical, antioxidant and barrier properties of the resulting PHBV-based films have been evaluated, as well as the antifungal activity against Aspergillus flavus and Candida albicans and the antimicrobial properties against both Gram (+) and Gram (−) bacterial strains. HS show great potential as natural additives for biopolymer matrices, since they confer antioxidant, antimicrobial, and antifungal properties to the resulting materials. In addition, barrier, optical and mechanical properties highlighted that the obtained films are suitable for sustainable active packaging. Therefore, the electrospinning methodology is a promising and sustainable approach to give biowaste a new life through the development of multifunctional materials suitable in the active bio-packaging. [Display omitted] • Redox behavior of humic substances makes them promising additives for biopolymers. • Electrospinning was used to obtain composite films with HS and PHBV biopolymer. • The resulting films had antioxidant, antimicrobial and antifungal properties. • Films exhibit good barrier, optical, mechanical properties for active packaging. • PHBV/HS films significantly extend shelf life of perishable food items. [ABSTRACT FROM AUTHOR]