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Transparent nanocomposite films made of surface-modified titanium dioxide nanoparticles and thermoplastic polyurethane are prepared via film casting approach showing enhanced refractive indexes and mechanical properties. Two different sets of composites were prepared up to 37.5 wt % of inorganic nanoparticles with a diameter <15 nm, one set using particles capped only with oleic acid and a second one with a bimodal system layer made of oleic acid and mPEO-5000 as coating agents. All of the composites show significantly enhanced refractive index and mechanical properties than the neat polymeric matrix. The transparency of nanocomposite films shows the excellent dispersion of the inorganic nanoparticles in the polymeric matrix avoiding aggregation and precipitation phenomena. Our study provides a facile and feasible route to produce transparent nanocomposite films with tunable mechanical properties and high refractive indices for various applications.

Exosomes are promising therapeutics for tissue repair and regeneration to induce and guide appropriate immune responses in dystrophic pathologies. However, manipulating exosomes to control their biodistribution and targeting them in vivo to achieve adequate therapeutic benefits still poses a major challenge. Here we overcome this limitation by developing an externally controlled delivery system for primed annexin A1 myo-exosomes (Exomyo). Effective nanocarriers are realized by immobilizing the Exomyo onto ferromagnetic nanotubes to achieve controlled delivery and localization of Exomyo to skeletal muscles by systemic injection using an external magnetic field. Quantitative muscle-level analyses revealed that macrophages dominate the uptake of Exomyo from these ferromagnetic nanotubes in vivo to synergistically promote beneficial muscle responses in a murine animal model of Duchenne muscular dystrophy. Our findings provide insights into the development of exosome-based therapies for muscle diseases and, in general, highlight the formulation of effective functional nanocarriers aimed at optimizing exosome biodistribution

I materiali polimerici svolgono un ruolo cruciale nella nostra vita quotidiana, tuttavia, la scienza dei polimeri si trova di fronte a sfide continue, in particolare nello sviluppo di metodi precisi e sostenibili per la fabbricazione di materiali avanzati in molte discipline. La polimerizzazione “free-radical” (FRP) è il metodo industriale più comune per la sintesi dei polimeri, in quanto offre semplicità, temperature relativamente basse (60-80 °C) e versatilità. Tuttavia, presenta importanti limitazioni, come la mancanza di controllo sul peso molecolare e sulla morfologia. Negli ultimi decenni, lo sviluppo di tecniche di polimerizzazione controllate (Reversible-Deactivation Radical Polymerization, RDRP) ha rivoluzionato la chimica dei polimeri, consentendo un controllo preciso del peso molecolare, della morfologia e delle modifiche successive alla polimerizzazione. Una tecnica RDRP di spicco è la polimerizzazione RAFT (reversible addition-fragmentation chain transfer). Nel 2014 questa tecnica è stata fusa con la fotochimica, culminando nella polimerizzazione PET (Photoinduced Electron/Energy Transfer)-RAFT, come alternativa alla RAFT tradizionale. Questa offre ulteriori vantaggi come la tolleranza all'ossigeno, la polimerizzazione a temperatura ambiente e il controllo spazio-temporale, aprendo nuove applicazioni in campi come litografia, la stampa 3D, la biomedicina, e molte altre. Infine, il meccanismo PET-RAFT offre intriganti vantaggi nel campo della sostenibilità, con l'impegno a sviluppare strategie di riciclo nuove o più efficienti per creare un'economia circolare per le plastiche tradizionali. Questa tesi mira a esaltare il potenziale della PET-RAFT indotta dalla luce, attraverso lo studio del suo meccanismo, la sua applicabilità nella produzione di materiali e il suo possibile ruolo nel riciclo chimico. All'interno di questo ambito di ricerca, sono stati studiati vari fotocatalizzatori a seconda dello scopo. Tra questi, nanoparticelle di biossido d, Polymeric materials play a crucial role in our daily life dominating many applications and wide markets. However, polymer science faces ongoing challenges, particularly in developing precise and sustainable methods for the fabrication of advanced materials across multiple disciplines. Free radical polymerization (FRP) is the most common industrial method for polymer synthesis, offering simplicity, relatively low temperatures, and versatility. However, it has important limitations, such as the lack of control over molecular weight and morphology. In the last decades, Reversible-Deactivation Radical Polymerization (RDRP) has revolutionized polymer chemistry, allowing for precise control over molecular weight, morphology, and post-polymerization modifications. One prominent RDRP technique is the reversible addition-fragmentation chain transfer (RAFT) polymerization. In 2014 this technique was merged with photochemistry, culminating in Photoinduced Electron/Energy Transfer (PET)-RAFT polymerization, as an alternative to traditional RAFT. It offers advantages such as oxygen tolerance, room temperature polymerization, and spatiotemporal control, opening new applications in lithography, 3D printing, biomedicine, etc. Finally, the PET-RAFT offers intriguing advantages in the field of sustainability, in fact the RAFT mechanism is based on an equilibrium that can be exploited not only for polymerization but also for depolymerization. The goal of this thesis is to elucidate the potential of light-induced PET-RAFT control polymerization, by the examination of its underlying mechanisms, its applicability in material manufacturing, and its potential role in chemical recycling. Within the scope of this research, various photocatalysts have been studied and tailored to specific goals. These include titanium dioxide (TiO2), Porphyrin-based catalysts, CsPbBr3 nanocrystals, and Eosin Y. Specifically, the utilization of TiO2 offered a unique opportunity to explore the polymerization me

Keratin is one of the most abundant structural proteins occurring in nature. The waste stream of low-grade wool from fabric preparation or chicken feathers from the poultry industry are keratin-rich materials currently underused. Hence, appropriate waste management and finding new methods to give value to these wastes are necessary. The transformation of underutilized biomass into high value-added products improves the environmental and economic sustainability of the value chain. Moreover, keratin shows versatile properties, including biocompatibility, biodegradability, and the presence of various functional groups. Keratin-rich waste is available at a low cost, making its use more attractive and advantageous because a waste stream will become a renewable source of materials. Wool and feathers waste comprises more than 90% of keratin proteins by weight with 5-10 mol% cysteine residues. The presence of intra- and intermolecular bonding, including the disulfide bridges formed between cysteine residues, ionic bonds, hydrogen bonds, or hydrophobic bonds, makes the keratin structure strong but, conversely, challenging to extract and reprocess. Consequently, the key to successful keratin extraction is the selection of appropriate chemicals to break these bonds. The initial part of this thesis investigates the efficiency of keratin extraction with the high yield target. Extraction protocols based on sulfitolysis and reduction with cysteine produced keratins that showed a good compromise between the molecular weights (in the range of 10−60 kDa) and yield (63 and 56%, respectively). In addition, the possibilities of keratin particle preparation were explored. Furthermore, this study describes the utilization of micro-contact printing technique to fabricate keratin-based micropatterns and evaluate their role in cellular guidance applications. Leveraging on the presence of the amino acid sequence leucine−aspartic acid−valine (LDV) in keratin, a tripeptide promoting cell adhesi, Keratin is one of the most abundant structural proteins occurring in nature. The waste stream of low-grade wool from fabric preparation or chicken feathers from the poultry industry are keratin-rich materials currently underused. Hence, appropriate waste management and finding new methods to give value to these wastes are necessary. The transformation of underutilized biomass into high value-added products improves the environmental and economic sustainability of the value chain. Moreover, keratin shows versatile properties, including biocompatibility, biodegradability, and the presence of various functional groups. Keratin-rich waste is available at a low cost, making its use more attractive and advantageous because a waste stream will become a renewable source of materials. Wool and feathers waste comprises more than 90% of keratin proteins by weight with 5-10 mol% cysteine residues. The presence of intra- and intermolecular bonding, including the disulfide bridges formed between cysteine residues, ionic bonds, hydrogen bonds, or hydrophobic bonds, makes the keratin structure strong but, conversely, challenging to extract and reprocess. Consequently, the key to successful keratin extraction is the selection of appropriate chemicals to break these bonds. The initial part of this thesis investigates the efficiency of keratin extraction with the high yield target. Extraction protocols based on sulfitolysis and reduction with cysteine produced keratins that showed a good compromise between the molecular weights (in the range of 10−60 kDa) and yield (63 and 56%, respectively). In addition, the possibilities of keratin particle preparation were explored. Furthermore, this study describes the utilization of micro-contact printing technique to fabricate keratin-based micropatterns and evaluate their role in cellular guidance applications. Leveraging on the presence of the amino acid sequence leucine−aspartic acid−valine (LDV) in keratin, a tripeptide promoting cell adhesi

Molecularly imprinted polymers (MIPs) display intriguing recognition properties and can be used as sensor recognition elements or in separation. In this work, we investigated the formation of hierarchical porosity of compositionally varied MIPs using 129Xe Nuclear Magnetic Resonance (NMR) and 1H Time Domain Nuclear Magnetic Resonance (TD-NMR). Variable temperature 129Xe NMR established the morphological variation with respect to the degree of cross-linking, supported by 1H TDNMR determination of polymer chain mobility. Together, the results indicate that a high degree of cross-linking stabilizes the porous structure: highly cross-linked samples display a significant amount of accessible mesopores that instead collapse in less structured polymers. No significant differences can be detected due to the presence of templated pores in molecularly imprinted polymers: in the dry state, these specific shapes are too small to accommodate xenon atoms, which, instead, probe higher levels in the porous structure, allowing their study in detail. Additional resonances at a high chemical shift are detected in the 129Xe NMR spectra. Even though their chemical shifts are compatible with xenon dissolved in bulk polymers, variable temperature experiments rule out this possibility. The combination of 129Xe and TDNMR data allows attribution of these resonances to softer superficial regions probed by xenon in the NMR time scale. This can contribute to the understanding of the surface dynamics of polymers.

Lithium metal batteries (LMBs) will be a breakthrough in automotive applications, but they require the development of next-generation solid-state electrolytes (SSEs) to stabilize the anode interface. Polymer-in-ceramic PEO/TiO2 nanocomposite SSEs show outstanding properties, allowing unprecedented LMBs durability and self-healing capabilities. However, the mechanism underlying the inhibition/delay of dendrite growth is not well understood. In fact, the inorganic phase could act as both a chemical and a mechanical barrier to dendrite propagation. Combining advanced in situ and ex situ experimental techniques, we demonstrate that oligo(ethylene oxide)-capped TiO2, although chemically inert toward lithium metal, imparts SSE with mechanical and dynamical properties particularly favorable for application. The self-healing characteristics are due to the interplay between mechanical robustness and high local polymer mobility which promotes the disruption of the electric continuity of the lithium dendrites (razor effect).

The synthesis of hydrogels that are based on poly-hydroxyethyl methacrylate, p(HEMA), network semi-interpenetrated with linear polyvinylpyrrolidone (PVP) was optimized in order to allow both a fast preparation and a high cleaning effectiveness of artistic surfaces. For this purpose, the synthesis parameters of the gel with PVP having a high molecular weight (1300 kDa) that were reported in the literature, were modified in terms of temperature, time, and crosslinker amount. In addition, the gel composition was modified by using PVP with different molecular weights, by changing the initiator and by adding maleic anhydride. The modified gels were characterized in terms of equilibrium water content (EWC), water uptake, conversion grade, and thermal properties by differential scanning calorimetry (DSC). The cleaning effectiveness of the gels was studied through the removal of copper salts from laboratory-stained specimens. Cleaning materials were characterized by electron paramagnetic resonance (EPR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and inductively-coupled plasma-mass spectrometry (ICP-MS). Cleaning was assessed on marble specimens by color variation measurements. The gel synthesis is accelerated by using PVP 360 kDa. The addition of maleic anhydride in the p(HEMA)/PVP network allows the most effective removal of copper salt deposits from marble since it acts as a chelator towards copper ions.

La Risonanza Magnetica Nucleare (NMR) è una delle tecniche più potenti per studiare proprietà chimiche e fisiche dei materiali. Negli ultimi anni, (LF-)NMR a basso campo si è affermata come una valida alternativa per indagare proprietà fisiche e strutturali di materiali organici. Opportune modifiche alle sequenze di impulsi hanno permesso di eseguire rilassometria, quantificazione di fasi, determinazione della densità di crosslink in molti materiali polimerici. La dipendenza dei parametri NMR, come T2 e T1, dal tempo di correlazione li rende di grande importanza per studiare la dinamica di molecole e catene polimeriche, e la possibilità di eccitare transizioni multiquanto (MQ) permette di ricavare gli accoppiamenti dipolari residui (Dres), che possono essere correlati con la densità di vincoli. Il comportamento NMR si correla bene con le proprietà macroscopiche. Lo scopo di questo lavoro è stato mostrare l'applicabilità di NMR nel dominio del tempo (TD) a basso campo a vari materiali con potenziale interesse industriale, per comprendere meglio la loro struttura e le relazioni struttura-proprietà. L'analisi del rilassamento dell'acqua è stata sfruttata per studiare il processo di termogelazione di soluzioni di metilcellulosa (MC). I tempi di rilassamento del solvente nel gel non rispettano le condizioni BPP a causa di moti vincolati. L'accelerazione del rilassamento e moti anisotropi sono coerenti con l'effetto combinato di acqua intrappolata nella regione amorfa di fibrille semicristalline e rilassamento del solvente alla superficie della regione cristallina. E’ discusso l'effetto della concentrazione e PM delle catene di MC sul rilassamento. MSE in D2O mostra formazione di frazione rigida, assegnata sia al dominio cristallino che interfacciale, corrispondente al 57% di tutti i protoni. La determinazione di questo grado di cristallinità spiega il comportamento semiflessibile delle fibrille e alti moduli dei gel. L'evoluzione dei tempi di rilassamento e, Nuclear Magnetic Resonance (NMR) is one of the most powerful techniques to study chemical and physical properties of materials. In the last years, Low Field (LF) NMR instruments affirmed as a valuable alternative to conduct physical and structural investigation of organic materials. Appropriate adjustment of pulse sequences has allowed to perform relaxometry experiments, phases quantification, determination of crosslinks density and degree of order in many polymeric materials. The dependence of NMR parameters, such as T2 and T1, on the correlation time of fast and slower motions makes them of major importance to study the microscopic dynamics of molecules and polymer chains and the possibility to excite multiple quantum (MQ) transitions permits to quantify residual dipolar couplings (Dres), which can be correlated with the density of constraints. The NMR behavior correlates well with macroscopic properties. In this work, we aimed at showing the applicability of LF Time Domain (TD) NMR to a range of materials with potential industrial interest, to better understand their structure and structure-property relationships. Analysis of water relaxation has been exploited to study the thermogelation process of methylcellulose (MC) solutions. Solvent relaxation times in gel deviates from BPP conditions due to hindered motion. Relaxation acceleration and motional anisotropy are consistent with combined effect of water trapped in the amorphous region of semicrystalline fibrils, and surface solvent relaxation onto the crystalline region. The effect of concentration and Mw of MC chains on relaxation is discussed. MSE measurements in D2O allows the determination of the rigid fraction, which is assigned to both crystalline and interfacial domain, corresponding to 57% of all protons, in accord with expected crystallinity and interfacial part of MC. The determination of this crystallinity degree in MC explains semiflexible behavior of fibrils and gels high moduli. Evolution of relax