Dario Allevi

The global rise in tattooing practices and laser-based removal has highlighted the need for a deeper mechanistic understanding of pigment clearance. To date, tattoo removal performed using Nd:YAG picosecond lasers has been predominantly interpreted as a photothermal fragmentation process, based largely on macroscopic and histological observations. However, nanoscale characterization of pigment transformations remains limited. The study introduces a minimal and versatile platform for the nanometric investigation of laser–pigment interactions, enabling systematic analysis under controlled conditions. Two widely used tattoo pigments were selected as model systems: carbon black (CB), clinically recognized as highly responsive to laser treatment, and titanium dioxide (TiO2), known for its resistance to removal. Pristine and laser-irradiated samples were characterized using transmission electron microscopy (TEM, HR-TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Contrary to the prevailing fragmentation paradigm, CB laser exposure induces aggregate coalescence, accompanied by expansion and partial graphitization of the primary structural units. In contrast, TiO2 exhibits negligible morphological or structural modifications upon irradiation, confirming its poor laser responsiveness. These findings challenge the conventional photothermolysis-based interpretation of tattoo removal and underscore the importance of nanoscale analyses to elucidate underlying mechanisms and its health effect.

The global rise in tattooing practices and laser-based removal has highlighted the need for a deeper mechanistic understanding of pigment clearance. To date, tattoo removal performed using Nd:YAG picosecond lasers has been predominantly interpreted as a photothermal fragmentation process, based largely on macroscopic and histological observations. However, nanoscale characterization of pigment transformations remains limited. The study introduces a minimal and versatile platform for the nanometric investigation of laser–pigment interactions, enabling systematic analysis under controlled conditions. Two widely used tattoo pigments were selected as model systems: carbon black (CB), clinically recognized as highly responsive to laser treatment, and titanium dioxide (TiO2), known for its resistance to removal. Pristine and laser-irradiated samples were characterized using transmission electron microscopy (TEM, HR-TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). Contrary to the prevailing fragmentation paradigm, CB laser exposure induces aggregate coalescence, accompanied by expansion and partial graphitization of the primary structural units. In contrast, TiO2 exhibits negligible morphological or structural modifications upon irradiation, confirming its poor laser responsiveness. These findings challenge the conventional photothermolysis-based interpretation of tattoo removal and underscore the importance of nanoscale analyses to elucidate underlying mechanisms and its health effect.

Water remediation technologies urgently require materials that are sustainable, efficient, and regenerable. Here, we report a dynamic covalent aerogel derived from chitosan and formylated lignin, enabling dual functionality in heavy metal adsorption and heterogeneous catalysis. The aerogel is formed through reversible imine bonds between chitosan and aldehyde‐functionalized lignin, synthesized via a mild Reimer–Tiemann reaction. The resulting monoliths exhibit high structural integrity, solvent and pH resistance (pH ≥ 7), and remarkable adsorption capacities for Cu ²⁺ , Pb ²⁺ , and Zn ²⁺ ions (up to 32.8 mg/g for Cu ²⁺ ). Density functional theory (DFT) calculations reveal tridentate coordination as the dominant binding mechanism. When loaded with Cu ²⁺ , the aerogels act as effective heterogeneous catalysts for the Chan–Lam crosscoupling reaction in ethanol. They achieve initial yields of up to 92% and retain their catalytic activity over multiple reuse cycles. Importantly, the dynamic covalent framework allows complete recovery and regeneration of all components, underscoring its potential as a circular, bio‐based platform for sustainable water detoxification and green catalysis.

Tryptophan derivatives are valuable non‐canonical amino acids widely used as precursors for the synthesis of bioactive molecules, as biophysical probes or introduced into polypeptides to improve or create entirely new functions. The enzyme tryptophan synthase (TrpS) provides a sustainable biocatalytic route to access these compounds directly from substituted indoles and l ‐serine. In this work, the substrate scope of Salmonella enterica tryptophan synthase (SeTrpS) was probed using a diverse library of synthetic indole derivatives bearing aryl, N ‐methylamino, alkynyl, and halogen substituents. Notably, SeTrpS displayed moderate to high conversions for most of the indoles tested, particularly for those substituted at positions 6 and 7. Two representative preparative scale reactions demonstrated the scalability of the process, affording the corresponding l ‐7‐ethynyltryptophan and l ‐5‐phenyltryptophan analogues in 58% and 25% yield, respectively, and excellent purity. This study contributes to illustrate the versatility of SeTrpS as a biocatalyst for the efficient and sustainable synthesis of structurally diverse tryptophan analogues, expanding the known substrate tolerance of this enzyme.

Surface functionalization of carbon nanotubes (CNTs) remains a key challenge in materials chemistry, particularly when aiming to enhance their chemical compatibility without compromising their intrinsic properties. In this study, we present a sustainable and efficient method for the covalent modification of multi-walled carbon nanotubes (MWCNTs) using ethyl 3-hydroxy-2-oxo-2H-pyran-6-carboxylate (PyrEst), a biosourced pyrone derivative obtained from renewable mucic acid.The functionalization proceeds via a thermally activated Diels–Alder-type reaction, achieving yields of up to 96% under mild conditions and without the use of solvents or catalysts.The resulting MWCNTs/PyrEst adducts were thoroughly characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and wide-angle X-ray diffraction (WAXD). High-resolution transmission electron microscopy (HRTEM) revealed morphological changes consistent with a hypothesized “bamboo effect,” indicating localized structural disruptions that preserve the overall nanotube framework.This approach combines green chemistry principles with high functionalization efficiency, offering a scalable route to tailor CNT surface properties for applications in nanocomposites, printable electronics, and dispersible systems.

The integration of antimicrobial activity and electrical conductivity in carbon-based materials requires precise control of surface chemistry and metal-carbon interfaces under scalable conditions. Here, a pyrrole-based Janus molecule is employed as a molecular interface to covalently functionalize sp2 carbon allotropes and to drive the in-situ nucleation of silver nanoparticles via a mild, surfactant-free Tollens-type process. This chemistry enables controlled Ag nanoparticle growth directly on carbon substrates without the use of external reductants.The functionalization strategy is applicable to different carbon allotropes and is successfully translated to an aqueous high-shear mixing process, demonstrating industrially relevant scalability while preserving structural and electronic properties. The resulting silver-carbon nanohybrids exhibit minimum bactericidal concentrations down to 7 µg/mL, negligible mammalian cytotoxicity, and electrical conductivity suitable for printable formulations. When incorporated into polymeric coatings and conductive inks, the materials achieve >99.9% bacterial reduction and stable piezoresistive behavior at significantly reduced silver loadings.These results demonstrate how interface-engineered carbon surfaces can enable multifunctional performance through scalable chemistry, offering a general route to silver-carbon nanohybrids with controlled structure and properties.

Over the past two decades, the copper(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC), commonly known as click chemistry, and C–H bond activation have gained significant attention and have emerged as key synthetic methodologies. In our efforts to synthesize fused nitrogen-containing heterocycles, we developed a palladium-catalyzed protocol for the synthesis of functionalized 7,10-dihydropyrrolo[3,2,1-ij][1,2,3]triazolo[4,5-c]quinolines and 5,8-dihydrobenzo[3,4][1,2,3]triazolo[4′,5′:5,6]azepino[1,2-a]indoles from suitable bromo-substituted N-propargyl-indoles. The reaction conditions demonstrate broad functional group compatibility including halogen, alkoxyl, cyano, ketone, and ester, affording the target compounds in good to high yields.

A Pd-catalyzed, simple, and efficient approach toward structurally diverse fused polycyclic [1,2,3]triazolo[4,5-c]quinoline and 4,5-dihydro-[1,2,3]triazolo[4,5-c]quinoline has been developed. The method is based on intramolecular Pd-catalyzed C–H activation and features operational simplicity, high atom economy, broad substrate scope, excellent yields, and good functional group tolerance. Gram-scale experiments and post-synthetic modifications were performed to extend the synthetic applicability of the proposed methodology and enhance the structural complexity of the obtained derivatives.

Rapeseed meal (RSM) is a by-product of rapeseed oil extraction and is a rich source of bioactive compounds, including proteins and antioxidants. This study compared two methods for extracting antioxidants from RSM: conventional ethanol Soxhlet extraction and supercritical CO₂ extraction. These procedures were applied to both native RSM and RSM after protein removal to evaluate their bio-compound composition and potential applications. HPLC-DAD, NMR, and GC/MS analyses revealed a rich polyphenolic profile in the extracts, including the presence of sinapic acid. The concentration of sinapic acid varied depending on the extraction method used. The anti-radical activity of the extracts was also analysed using the DPPH assay, which confirmed the potential of RSM as a source of antioxidants for use in cosmetics, food, and pharmaceutical formulations.