Browsing by Author "Rojo, Luis"
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- Biofunctional silk sericin hydrogels: a versatile platform with potential for tissue healing and regenerationPublication . Veiga, Anabela; Ribeiro, Viviana; Ramírez-Jiménez, Rosa Ana; Aguilar, Maria Rosa; Rojo, Luis; Oliveira, Ana L.Discarded silk sericin protein (SS) presents a high yet underexplored potential as a biomaterial for tissue engineering (TE). Despite its biocompatibility, antioxidant activity, and moisture retention properties, its poor stability in aqueous media has limited broader application. In this work, we developed and characterized SS-based hydrogels using tannic acid (TA) and horseradish peroxidase (HRP) crosslinking systems to address these limitations and expand their use in skin TE. Hydrogels were prepared using SS concentrations of 2.5 % and 5 % (w/v) and evaluated for rheological behavior (G′ ranging from 100 to 10,000 Pa), swelling (up to 24 %), retention capacity (stable over 24–30 h), and degradation in proteolytic environments (mass loss ranging from ∼0–11 %, depending on formulation). TA-crosslinked hydrogels showed strong fluid retention and are suitable for high-moisture 3D wound dressings and coating applications. HRP-crosslinked hydrogels demonstrated tunable mechanical properties, shear-thinning behavior, and full recovery post-deformation, making them ideal for use as bioinks in 3D bioprinting and injectable matrices. In vitro assays confirmed cytocompatibility, with viability exceeding 85 %, and successful cell encapsulation and proliferation. Overall, this study presents a versatile SS-based hydrogel platform with potential for various biomedical applications, particularly in skin tissue healing and regeneration.
- Innovative processing and sterilization techniques to unlock the potential of silk sericin for biomedical applicationsPublication . Veiga, Anabela; Ramírez-Jiménez, Rosa Ana; Santos-Rosales, Víctor; García-González, Carlos A.; Aguilar, Maria Rosa; Rojo, Luis; Oliveira, Ana L.Silk sericin (SS), a by-product of the textile industry, has gained significant attention for its biomedical potential due to its biocompatibility and regenerative potential. However, the literature lacks information on SS processing methods and the resulting physicochemical properties. This study represents the first step in protocol optimization and standardization. In the present work, different processing techniques were studied and compared on SS extracted from boiling water: evaporation, rotary evaporation, lyophilization, and dialysis, which presented a recovery yield of approximately 27–32%. The goal was to find the most promising process to concentrate extracted SS solutions, and to ensure that the SS structure was highly preserved. As a result, a new cryo-lyophilization methodology was proposed. The proposed method allows for the preservation of the amorphous structure, which offers significant advantages including complete dissolution in water and PBS, an increase in storage stability, and the possibility of scaling-up, making it highly suitable for industrial and biomedical applications. The second part of the work focused on addressing another challenge in SS processing: efficient and non-destructive sterilization. Supercritical CO2 (scCO2) has been gaining momentum in the last years for sterilizing sensitive biopolymers and biological materials due to its non-toxicity and mild processing conditions. Thus, scCO2 technology was validated as a mild technique for the terminal sterilization of SS. In this way, it was possible to engineer a sequential cryo-lyophilization/scCO2 sterilization process which was able to preserve the original properties of this natural silk protein. Overall, we have valorized SS into a sterile, off-theshelf, bioactive, and water-soluble material, with the potential to be used in the biomedical, pharmaceutical, or cosmetic industries.
- Porphyridium cruentum: a factory for the production of a new polysaccharide-based biomaterial for tissue regenerationPublication . Duarte, Marta M.; Suprinovych, Artem; Silva, Inês V.; Ramos, Oscar L.; Costa, Joana R.; Rojo, Luis; Oliveira, Ana L.Marine algae and their metabolites have been widely recognized for their bioactive properties with applications in various industries, such as nutraceutical, cosmetical, and pharmaceutical. In this study, the best strategy for the extraction and processing of the exopolysaccharides (EPS) from Poryphydium cruentum for a laboratory scale was discussed, and the collected, purified EPS fraction was extensively characterized. The results show that impurities and other co-precipitants can be significantly reduced via trichloroacetic acid (TCA) treatment, followed by dialysis, resulting in a more purified EPS fraction with a higher carbohydrate content and solubility ability, at the cost of lower mass yield. The obtained EPS fraction was of a high molecular weight, presented a high crystallinity index, was thermally stable and cytocompatible within the range of tested concentrations. These results show its potential to be used as a new platform for healing and regeneration of chronic wounds.
- Ready-to-use silkworm sericin: finding the best starting pointPublication . Veiga, Anabela; Castro, Filipa; Rocha, Fernando; Blanca, Vasquez Lasa; Rojo, Luis; Oliveira, Ana L.
- Revolutionizing silk production: a cutting-edge, eco-friendly approach to sericin synthesis and sterilizationPublication . Bernardes, Beatriz G.; Veiga, Anabela; Rojo, Luis; Oliveira, Ana L.
- Vitamin B9 derivatives as carriers of bioactive cations for musculoskeletal regeneration applications: synthesis, characterization and biological evaluationPublication . Fernández-Villa, Daniel; Asensio, Gerardo; Silva, Manuel; Ramírez-Jiménez, Rosa Ana; Saldaña, Laura; Vilaboa, Nuria; Leite-Oliveira, Ana; Román, Julio San; Vázquez-Lasa, Blanca; Rojo, LuisThe development of new drugs for musculoskeletal regeneration purposes has attracted much attention in the last decades. In this work, we present three novel vitamin B9 (folic acid)-derivatives bearing divalent cations (ZnFO, MgFO and MnFO), providing their synthesis mechanism and physicochemical characterization. In addition, a strong emphasis has been placed on evaluating their biological properties (along with our previously reported SrFO) using human mesenchymal stem cells (hMSC). In all the cases, pure folate derivatives (MFOs) with a bidentate coordination mode between the metal and the folate anion, and a 1:1 stoichiometry, were obtained in high yields. A non-cytotoxic dose of all the MFOs (50 μg/mL) was demonstrated to modulate by their own the mRNA profiles towards osteogenic-like or fibrocartilaginous-like phenotypes in basal conditions. Moreover, ZnFO increased the alkaline phosphatase activity in basal conditions, while both ZnFO and MnFO increased the matrix mineralization degree in osteoinductive conditions. Thus, we have demonstrated the bioactivity of these novel compounds and the suitability to further studied them in vivo for musculoskeletal regeneration applications.