Investigating the Structure-Related Properties of Cellulose-Based Superabsorbent Hydrogels

Superabsorbent hydrogels are macromolecular networks able to absorb and retain large amounts of water solutions within their fine mesh-like structure. More importantly, they are capable of multiple swelling/shrinking transitions in response to specific environmental cues (e.g., pH, ionic strength, temperature, presence of given electrolytes), thus exhibiting a stimuli-sensitive behavior, which makes them appealing for the design of smart devices in a number of technological fields. In particular, in the last two decades, cellulose-based superabsorbent hydrogels have proven to be an environmentally friendly and cost-effective alternative to acrylamide-based products. This chapter reviews the relationship between the molecular structure of cellulose-based hydrogels and their physicochemical properties. First, the network formation through the use of different cellulose derivatives and chemical or physical crosslinking agents is presented. Successively, the smart swelling capability of the hydrogels as a function of composition and structure is thoroughly discussed. Finally, several approaches to the hydrogel characterization are reviewed, with focus on the assessment of key mechanical, thermal and morphological properties

Bioactivation Routes of Gelatin-Based Scaffolds to Enhance at Nanoscale Level Bone Tissue Regeneration

The present work is focused on the development of gelatin-based scaffolds crosslinked through carbodiimide reaction and their bioactivation by two different methods: (i) surface modification by inorganic signals represented by hydroxyapatite nanoparticles precipitated on scaffold through biomimetic treatment; (ii) analog of BMP-2 peptide decoration. The results showed the effects of polymer concentration and crosslinking time on the physico-chemical, morphological, and mechanical properties of scaffolds. Furthermore, a comparative study of biological response for both bioactivated structures allowed to evaluate the influence of inorganic and organic cues on cellular behavior in terms of adhesion, proliferation and early osteogenic marker expression. The bioactivation by inorganic cues induced positive cellular response compared to neat scaffolds in terms of increased cell proliferation and early osteogenic differentiation of human mesenchymal stem cell (hMSC), as evidenced by the Alkaline phosphatase (ALP) expression. Similarly BMP-2 peptide decorated scaffolds showed higher values of ALP than biomineralized ones at longer time. The overall results demonstrated that the presence of bioactive signals (either inorganic or organic) at nanoscale level allowed an osteoinductive effect on hMSC in a basal medium, making the modified gelatin scaffolds a promising candidate for bone tissue regeneration

Supplementation with ribonucleotide-based ingredient (Ribodiet®) lessens oxidative stress, brain inflammation, and amyloid pathology in a murine model of Alzheimer

Abstract Alzheimer's disease (AD) is the most common type of dementia worldwide, characterized by the deposition of neurofibrillary tangles and amyloid-β (Aβ) peptides in the brain. Additionally, increasing evidence demonstrates that a neuroinflammatory state and oxidative stress, iron-dependent, play a crucial role in the onset and disease progression. Besides conventional therapies, the use of natural-based products represents a future medical option for AD treatment and/or prevention. We, therefore, evaluated the effects of a ribonucleotides-based ingredient (Ribodiet®) in a non-genetic mouse model of AD. To this aim, mice were injected intracerebroventricularly (i.c.v.) with Aβ1–42 peptide (3 µg/3 μl) and after with Ribodiet® (0.1–10 mg/mouse) orally (p.o.) 3 times weekly for 21 days following the induction of experimental AD. The mnemonic and cognitive decline was then evaluated, and, successively, we have assessed ex vivo the modulation of different cyto-chemokines on mice brain homogenates. Finally, the level of GFAP, S100β, and iron-related metabolic proteins were monitored as markers of reactive gliosis, neuro-inflammation, and oxidative stress. Results indicate that Ribodiet® lessens oxidative stress, brain inflammation, and amyloid pathology via modulation of iron-related metabolic proteins paving the way for its rationale use for the treatment of AD and other age-related diseases

The synergistic effect of an imidazolium salt and benzotriazole on the protection of bronze surfaces with chitosan-based coatings

Abstract The class of imidazolium salts contains effective anticorrosion additives for metal substrates. This study evaluated the potential of 1-carboxymethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (HO 2 CC 1 MImNTf 2 ) for application in cultural heritage, exploring it as anticorrosion additive in chitosan-based coatings for the protection of copper-based alloys. Under accelerated corrosion conditions with HCl vapor, the chitosan coating with HO 2 CC 1 MImNTf 2 was less effective than the one with benzotriazole. The coating with a combination of HO 2 CC 1 MImNTf 2 and benzotriazole resulted in the optimal protective efficacy of the bronze surface, and it also maintained high transparency without changing the bronze appearance

Proprietà biologiche di materiali sintetizzati con la tecnica sol-gel

Il lavoro di tesi si basa sulla sintesi di materiali preparati con la tecnica sol-gel, in particolar modo lo studio è stato focalizzato sulla sintesi di ibridi organo-inorganici. Il metodo sol-gel ha ricevuto notevole attenzione negli ultimi anni grazie ai suoi vantaggi come la bassa temperatura di processo, alta omogeneità dei prodotti finali. Generalmente, il prodotto formato può essere considerato come un polimero inorganico avendo un network strutturale tridimensionale capace di intrappolare molecole di polimero organico. Gli ibridi si prospettano come un’alternativa per ottenere materiali con caratteristiche innovative. La sintesi di tali materiali ha lo scopo di eliminare, gli svantaggi connessi all’utilizzo dei singoli componenti quali i polimeri e i ceramici. Nel caso dei polimeri, accanto ai vantaggi rappresentati dalla bassa densità, alta tenacità e quindi facili da lavorare, abbiamo anche svantaggi associati alla bassa resistenza meccanica e alla degradazione. I ceramici hanno il vantaggio di avere elevata resistenza, buona biocompatibilità e non si degradano (inerzia chimica), tra gli svantaggi ricordiamo la fragilità e le difficoltà di lavorazione. Nel lavoro sono stati realizzati, con la tecnica sol-gel, ibridi organo-inorganici per i quali sono state considerate due tipi di matrici inorganiche, il sistema ZrO2-5wt%Y2O3 e il sistema a base di TiO2, la parte organica per entrambi i sistemi è rappresentata da un poliestere biodegradabile quale il poli-e-caprolattone (PCL). Tali campioni sono stati caratterizzati sia da un punto di vista chimico che biologico per poterli identificare come biomateriali. Le prestazioni dei materiali impiegati in campo medico sono valutate in base alla loro biocompatibilità e biofunzionalità. La biocompatibilità rimane il tema centrale per le applicazioni dei biomateriali in medicina. Oltre allo studio della biocompatibilità di questi materiali, in questo lavoro è stata studiata anche la bioattività, ossia la capacità dei materiali di promuovere la formazione di idrossiapatite sulla loro superficie quando sono posti a contatto con un fluido biologico (SBF), e quindi di valutare la loro capacità di osteointegrarsi in seguito ad un impianto. L’incorporazione di ampicillina in questi materiali ha permesso, inoltre, lo studio del rilascio controllato dell’antibiotico. Lo scopo di sviluppare sistemi a rilascio controllato è quello di ridurre la frequenza del dosaggio o/e aumentare l’efficacia del farmaco attraverso la circoscrizione del sito d’azione, di conseguenza riducendo la dose richiesta o provvedendo a un rilascio di farmaci costante. È ovvio che questo sistema di rilascio avrà requisiti differenti per differenti stati di disagio e per differenti farmaci. La potenzialità di questi materiali innovativi è certamente la produzione di composti con struttura più ordinata e anisotropa

Hydrogel-Based Platforms for the Regeneration of Osteochondral Tissue and Intervertebral Disc

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