Here, a formulation of silver nanoparticles (AgNPs) and two natural polymers such as alginate (ALG) and nanocrystalline cellulose (CNC) was developed for the 3D printing of scaffolds with large surface area, improved mechanical resistance and sustained capabilities to promote antimicrobial and cytotoxic effects. Mechanical resistance, water content, morphological characterization and silver distribution of the scaffolds were provided. As for applications, a comparable antimicrobial potency against S. aureus and P. aeruginosa was demonstrated by in vitro tests as function of the AgNP concentration in the scaffold (Minimal Inhibitory Concentration value: 10 mg/mL). By reusing the 3D system the antimicrobial efficacy was demonstrated over at least three applications. The cytotoxicity effects caused by administration of AgNPs to hepatocellular carcinoma (HepG2) cell culture through ALG and ALG/CNC scaffold were discussed as a function of time and dose. Finally, the liquid chromatography-mass spectrometry (LC-MS) technique was used for targeted analysis of pro-apoptotic initiation and executioner caspases, anti-apoptotic and proliferative proteins and the hepatocyte growth factor, and provided insights about molecular mechanisms involved in cell death induction.

The increase of agri-food wastes by agriculture and industries is one of the main causes of environmental pollution. Here we propose the recycling of Cynara scolymus L. wastes to obtain polymorph II cellulose nanocrystals (CNC). Two different extraction procedures are compared: (i) Soxhlet extraction in an ethanol/toluene mixture, and (ii) water boiling of the agricultural waste. Both procedures were followed by purification of cellulose fibers through bleaching treatments and extraction of cellulose nanocrystals by acid hydrolysis. CNCs have been extensively characterized by FTIR spectroscopy, electrophoretic light scattering measurements, X-ray powder diffraction methods, transmission electron microscopy, and thermogravimetric analyses. Extracted CNC are rod-like-shaped polymorph IIs with a good crystallinity index, and they are characterized by high hydrogen bonding intensity. The ELS measurements on samples from both procedures show good results regarding the stability of the CNC II sol (ζ < −40 ± 5 mV), comparable to that of the CNC polymorph I. Both polymorph II CNCs show better thermal stability, compared to CNC I. The results show that the easy extraction procedure from agricultural Cynara scolymus L. waste can be used to produce high-quality cellulose nanocrystals as a green alternative to the commonly used synthetic route.

Due to the release of active pharmaceutical compounds in wastewater and their persistence in the environment, dangerous consequences can develop in the aquatic and terrestrial organisms. Chitosan/Ag/TiO₂ 3D printed scaffolds, at different Ag nanoparticle concentrations (10, 100, 1000 ppm) are investigated here as promising materials for photocatalytic degradation under the UV–Vis irradiation of pharmaceutical compounds in wastewater. As target drugs, amoxicillin, paracetamol and their 1:1 mix were selected. Ag nanoparticles increase the photocatalytic efficiency of the system based on titanium dioxide embedded in the chitosan scaffold: in the presence of Chitosan/Ag₁₀₀/TiO₂, the selected pharmaceuticals (PhCs), monitored by UV–Vis spectroscopy, are completely removed in about 2 h. The photodegradation products of the PhCs were identified by Liquid Chromatography–Mass Spectroscopy and assessed for their toxicological impact on six different bacterial strains: no antibacterial activity was found towards the tested strains. This new system based on Ag/TiO₂ supported on 3D chitosan scaffolds may represent an effective strategy to reduce wastewater pollution by emerging contaminants.

Self-cleaning and hydrophobic treatments based on TiO₂ and SiO₂ nanoparticles are widely applied for the preservation of cultural heritage materials, to improve their resilience in polluted environments. Excellent results have been obtained on stone materials, but experiments on painted stone surfaces, such as wall paintings and polychrome plasters used in historic buildings, are still limited. In this work, we present a study on the use of water dispersions of TiO₂ nanoparticles obtained via sol-gel and organically modified silica (OrMoSil) for cleaning and protective purposes on Lecce stone, a carbonate stone, widely used for its excellent workability but easily attacked by atmospheric agents and pollutants. First, we evaluated the harmlessness of the treatment on Lecce stone through colorimetric tests, water absorption by capillarity and permeability to water vapor. The photocatalytic activity of the TiO₂ nanoparticles was assessed by photo-degradation of methyl orange and methylene blue dyes. The dispersion was then applied on painted samples prepared according to ancient recipes to confirm the effectiveness of the cleaning. The proposed TiO₂/OrMoSil-based coating can act as a self-cleaning and protective treatment on lithic surfaces to prevent degradation phenomena and preserve the original appearance of the monument.

In this study, the use of surfactant-free water-in-oil gelled emulsions containing benzyl alcohol (BAl/w) is proposed as an alternative to the more traditional use of organic solvents for removing varnishes. To mitigate the strong swelling and solvent action of benzyl alcohol and protect the paint and the underlying layers, temporary hydrophobization with cyclomethicone D5 has been proposed. The aim of this study was to evaluate the application of BAl/w surfactant-free, constructed with three different gelling agents of the aqueous dispersing phase (xanthan gum, agar-agar, and polyacrylate) on the surface of an oil painting varnished with and without preliminary saturation with D5. The role of pH, which can influence the ionization, and therefore the water solubility of terpene molecules and all other acid species present on the surface, was also studied. Fourier transform infrared (FT-IR) and Raman spectroscopies were used to characterize the pigments and the surface before and after varnish removal. Elemental analysis and any morphological changes were evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The leaching efficiency of each surfactant-free emulsion applied on the paint surface was evaluated using a gas chromatography/mass spectroscopy (GC/MS) analysis: the fatty acid content was established in each sample before and after the treatments.