Eco-design di materiali avanzati per la protezione della salute dell’uomo e dell’ambiente

The widespread manufacturing of nanomaterials and nano-enabled products (NEPs) has led to concerning human and environmental exposure levels. The lack of knowledge regarding the occupational, consumer, and environmental potential adverse effects of this burgeoning technology has ignited serious safety issues and highlighted the importance of a comprehensive risk evaluation. Safety and Sustainability by Design (SSbD) is a concept that thanks to a prevention approach aims to reduce the hazards at the early stages of product development. The combined implementation of safety measures and risk assessment will have to meet regulatory infrastructures to deliver SSbD guidelines and tools. To reach this goal it will be crucial to monitor the effects of these products and their manufacturing processes on human and environmental health. Structure-properties correlations must be studied to determine general guidelines and deliver safer and more sustainable design alternatives to the actual nanomaterials. A proper design of the synthesis step directly affects the structure of the nanomaterials allowing to building of the desired physicochemical, functional, and safety profiles. In this context, the design or re-design of a nanomaterial is an early-stage measure that can effectively improve the safety and sustainability of the product creating a bridge between design space and functional properties. A full life cycle assessment is required to link the nanomaterials design step to the nano-enabled products manufacturing, use phase, and end of life. To contribute to this research field, during this work, three main topics were assessed: the synthesis of antimicrobial silver nanoparticles and their implementation into several case studies, the synthesis of gold-platinum nanoparticles for application as a catalyst in biomass valorization, and the production of biopolymeric scaffolds embedding natural-derived active phases for the wastewater remediation. Three AgNPs synthesis methods using different capping agents were studied: - Quaternized hydroxyethyl cellulose is a natural-derived biopolymer with positive charged quaternary ammonium groups that confers antibacterial activity to this compound. - Curcumin is a natural-derived organic molecule with intrinsic antimicrobial and antioxidant properties. - Cyclic lipopeptide biosurfactant derived from bacterial metabolism which possesses antimicrobial properties thanks to its cell wall lysis capability. A wide-ranging physicochemical characterization (TEM, XRD, ICP-OES, UV-Vis, DLS, ELS) was performed to correlate synthesis parameters to physicochemical and functional properties. The so-obtained AgNPs were tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus and Listeria innocua) bacteria, demonstrating excellent antibacterial activity against all the tested bacterial strains. Antiviral tests were performed against the SARS-CoV-2 enveloped virus and BK polyomavirus non-enveloped virus, proposing an antiviral mechanism of action of AgNPs involving the interaction of AgNPs with the viral envelope inhibiting the attachment to cell’s receptors. The most active AgNPs variants were selected for the implementation into nano-enabled products within different case studies: antimicrobial textiles, paper, and biopolymeric film and scaffolds. The antimicrobial properties were successfully transferred from the nanomaterial to the nano-enabled product. Thanks to these case studies workers, users, and environmental exposures were assessed. NEPs antibacterial efficacy and product durability were evaluated. The Safe and Sustainable by Design approach was applied for the synthesis of gold-platinum nanoparticles catalysts. The green chemistry principles were implemented on multiple levels, first for the safe and sustainable synthesis of the nanoparticles and then in their application for biomass valorization by converting biomass wastes into chemical building blocks. Two different gold-platinum nanoparticles structures were studied core-shell (gold core and a platinum external shell) and alloy. The correlation between the structure and the catalytic activity of these materials was studied thanks to an in-depth physicochemical characterization (TEM, XRD, ICP-OES, UV-Vis, DLS, ELS). The catalytic activity was evaluated in the model reaction of hydrogenation of nitrophenol to aminophenol. Synergistic effects were observed for the bi-metallic nanoparticles, thanks to which a reduced load of platinum allows excellent catalytic activity. The increasing contamination of hydric resources caused by human activities has highlighted the necessity to develop new technologies for wastewater remediation. From a circular economy perspective, natural adsorbent materials were selected for this purpose. Clays and hydrotalcites share a layered structure able to host counterions, the deriving ion exchange capability has been efficiently exploited for the adsorption of heavy metals and organic pollutants. The selected adsorbents were characterized by XRD, BET, and ELS, subsequently, they were tested in the adsorption of simulated pollutants, namely the cationic dye rhodamine B, anionic dye methyl orange, and copper (II) cation. Clays and hydrotalcites were embedded into renewable seaweed-derived biopolymeric scaffolds made of k-carrageenan, chitosan, or agarose to improve their handleability. The pollutants adsorption tests were replicated on the scaffolds and the resulting adsorption process kinetic followed the pseudo-second-order model.