Browsing by Author "Paredes, Maria G."

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    Crosslinked oxidized-nanocellulose/chitosan hydrogels as a scaffold matrix for mesenchymal stem cell growth
    (2024) Marino, Mayra A.; Oyarce, Karina; Tobar, Catalina; del Rio, Rodrigo Segura; Paredes, Maria G.; Pavez, Paulina; Sarabia, Mauricio; Amoroso, Alejandro; Concha, Jose L.; Norambuena-Contreras, Jose; Barjas, Gustavo Cabrera; Castano, Johanna
    Mesenchymal stem cells (MSC) are recognized for their immunomodulatory effects and regenerative properties, being promising therapeutic agents for a wide range of diseases. To ensure a localized effect of MSC in the organism biobased hydrogels have been tested for their ability to act as a matrix-embedded to improve MSC targeted delivery. In this context, nanocellulose (NC) has been used for drug delivery, showing biocompatibility and durability in time, but until now NC has not been tested for MSC growth exploiting the size and aldehyde content of NC. In this study, cellulose nanocrystals (CNC), cellulose nanofibers (CNF) and microfibrillated cellulose (MFC) were studied after one-pot oxidation and further crosslinking with chitosan (mass ratio 1:5). Size and aldehyde content of oxidized NC samples were evaluated to analyze their influence on the hydrogel's properties. The crosslinked hydrogels were analyzed by FESEM, swelling ability, FTIR, compression tests, thermal stability, and stability in culture cell conditions. Oxidized-MFC hydrogel improved the mechanical stability and swelling behavior, but it lacks stability at cell conditions possibly due to its low aldehyde content (0.54 mmol/g). Conversely, oxidized CNF and oxidized CNC formed suitable crosslinked hydrogels for cell adhesion, and for growing and proliferating of MSC 3D spheroids after 120 h. However, only hydrogel with PO-CNF/chitosan shows antibacterial activity as well as MSC proliferation.
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    Recycled ionic liquid vs . deep eutectic solvent in cellulose nanocrystals production: Characterization, techno-economic analysis, and life cycle assessment
    (2024) Marino, Mayra A.; Rueda-Ordonez, Diego; Paredes, Maria G.; Tapia, Ricardo A.; Pita, Ramon; Pavez, Paulina
    Three scenarios involving aqueous mixtures of neoteric solvents have been evaluated as solvents and catalysts for the cellulose hydrolysis reaction to obtain CNC in high yields (>70%). The scenarios considered were: scenario 1 (S1) involves a recyclable ionic liquid dilution of [Hmim][(HSO4)(H2SO4)]/H2O (64 wt% IL); scenario 2 (S2) another recyclable dilution of [Hmim][(HSO4)(H2SO4)]//H2O (80 wt% IL) and scenario 3 (S3) S3 ) a non-recyclable ternary deep eutectic solvent (60 wt% DES: choline chloride: oxalic acid/30 wt% PA/10 wt% water). Experimental analysis, techno-economic, and life cycle analysis (LCA) indicate that S1 emerges as a suitable scenario among the three analyzed. S1 demonstrated the highest competitiveness, with a lower raw material cost per gram of CNC produced (US$0.81/g) and lower environmental contributions concerning climate change and fossil fuel depletion, accounting mainly for its recyclability. Therefore, the recyclable dilution of 64 wt% IL used in S1 appears to be the most viable option for sustainable and environmentally conscious CNC production. Besides, the physicochemical properties of the CNC were revealed: aspect ratio range 7-8, high dispersion stability related to zeta potential >-40 mV, good crystallinity range 50-80%, and thermal stability with Tonset> 300 degrees C. These results guided towards a scenario with crucial advantages: a diluted IL that retains its acidity after reuse cycles by a facile recovery process, maintaining high CNC production performance and providing low environmental impacts.