CBQF - Documentos de Conferências / Conference Objects
Permanent URI for this collection
Browse
Recent Submissions
- A new bioactive dermal substitute for wound healing and skin regenerationPublication . Rosadas, Marta; Sousa, Teresa; Reis, Mariana; Sousa, Clara; Sousa, Alda; Sánchez Espinel, Christian; Peleteiro, Mercedes; González-Fernández, África; Ribeiro, Viviana P.; Oliveira, Ana LeiteAim: Rabbit skin is an abundant agri-food by-product with interesting properties to be up-cycled into a xenogeneic dermal substrate for skin and regeneration. When decellularized, rabbit dermis preserves collagen–elastin components that can guide cell behavior. However, decellularization conditions can also influence the preservation of tissue architecture and may introduce immunogenic triggers such as damage-associated molecular patterns (DAMPs). This work aimed to develop low-immunogenicity decellularized dermal matrices (dDMs) using rabbit skin as by- product. Method: dDMs were generated using optimized chemical decellularization protocols and evaluated for structural and biochemical integrity using SEM, tensile testing, FTIR, proteomics, and DNA, GAGs, collagen, and elastin quantification. Immunogenicity was assessed throughendotoxin analysis and by exposing human peripheral blood mononuclear cells (PBMCs) to the matrices to measure complement activation, ROS, apoptosis, activation markers, and cytokine release. The ability of dDMs to support human dermal fibroblasts (hDFs) and keratinocytes (HaCaTs) was examined over 14 days using Alamar Blue, BrdU, SEM, and DAPI/phalloidin staining. Results/Discussion: dRDMs preserved native collagen–elastin architecture, and GAG levels were comparable to human dermis. Residual DNA confirmed effective decellularization. No significant immune activation occurred: ROS and apoptosis were absent, and PBMC activation matched controls with only mild monocyte and B-cell responses. Cytokine release indicated modest inflammatory signaling induction. Interestingly, matrices with lower DNA content triggered stronger immune responses, suggesting biocompatibility is influenced more by processing-related factors (detergent residues or DAMPs) than by DNA levels. hDF and HaCaT adhesion, viability, and proliferation were maintained for 14 days. Conclusion: dRDMs showed favorable structural, biochemical, and immunological profiles and supported dermo-epidermal cell growth, demonstrating potential as bioactive dermal substitutes for skin regeneration.
- Beyond DNA removal: assessing the immunological response to decellularized rabbit dermal matricesPublication . Rosadas, Marta; Sánchez Espinel, Christian; Peleteiro, Mercedes; Sousa, Alda; Ribeiro, Viviana P.; González-Fernández, África; Oliveira, Ana L.Introduction: Decellularized matrices have attracted considerable attention in tissue engineering and regenerative medicine due to their ability to preserve the biochemical composition and microarchitecture of native tissues. Although DNA removal is commonly used as the main indicator of decellularization efficiency, other factors—such as endotoxin contamination, damage-associated molecular patterns, and residual reagents—can significantly influence the host immune response. In this study, decellularized rabbit dermal matrices (dRDM) produced using two different protocols— resulting in DNA levels below or above the proposed safety threshold of 50 ng/mg dry tissue—were evaluated for their immunological performance. Conclusions: Two decellularization protocols produced dRDMs with distinct biological profiles. Although the SDC 3H protocol achieved DNA levels below the recommended threshold, it was associated with greater collagen degradation, whereas the SDC 30 min protocol better preserved native dermal collagen. Both matrices were sterile, endotoxin-free, and did not induce ROS production in PBMCs. However, dry dRDMs and SDC 3H-treated matrices promoted complement activation and increased PBMC necrosis. Overall, despite not meeting the recommended DNA threshold, the SDC 30 min protocol demonstrated superior immunocompatibility and collagen preservation, highlighting that DNA content alone is not a reliable predictor of decellularization efficiency. Instead, immunocompatibility, collagen integrity, physical cell–matrix interactions, and potential detergent residues play a critical role in defining matrix performance.
- Decellularized dermal matrix-based hydrogels and their potential as immunomodulatory biomaterialsPublication . Pereira, Ana Beatriz V.; Rosadas, Marta; Gomes, Patricia; Sousa, Alda; Oliveira, Ana Leite; Ribeiro, Viviana P.
- Packaging atmosphere and confinement as key factors in shelf-life extension of live clamsPublication . Goes, Cintia; Vieira, Tiago Monteiro; Pereira, Joel; Mota, Ana; Cruz, Andreia; Sivertsvik, Morten; Poças, Maria de FátimaLive bivalve molluscs are highly valued for their nutritional, gastronomic, and commercial qualities. However, they are extremely perishable, which increases production losses and waste in the supply chain. This study aimed to evaluate the shelf-life and physiological quality of live Venerupis corrugata clams stored at 3 ± 1°C in different packaging systems evaluating the effect of high-oxygen modified atmosphere packaging versus ambient air, and of physical confinement in net bags versus loose storage. Survival percentage, gases concentration, volatile organic compounds, pH, glycogen content, and biogenic amines were monitored throughout storage. Results showed that survival and physiological quality were strong influenced by the combined effects of oxygen availability and confinement. High-oxygen MAP delayed mortality by sustaining aerobic metabolism for longer, thereby reducing the respiration quotient. Physical confinement was critical in maintaining intravalvular liquid and preserving clam viability. Nevertheless, the modelled survivability extension was limited to only 1 day under optimal MAP conditions and confinement, highlighting the intrinsic sensitivity of this species.
- Decellularized dermal matrix-based hydrogels and their potential as immunomodulatory biomaterialsPublication . Pereira, Ana Beatriz V.; Rosadas, Marta; Gomes, Patricia; Sousa, Alda; Oliveira, Ana Leite; Ribeiro, Viviana P.Decellularization is a process that aims to remove cellular and nuclear components from tissues, while preserving the bioactivity of the extracellular matrix (ECM) and minimizing the immunogenicity. Decellularized ECMs positively influence cell adhesion, proliferation, and differentiation, establishing them as promising biomaterials for tissue regeneration. Recent research has highlighted their potential immunomodulatory effect, including their ability to regulate the crosstalk between macrophages and T cells and influence the polarization of macrophages, which leads to an anti-inflammatory and pro-remodelling response. For example, hydrogels derived from decellularized dermal matrix (dDM) have reported potential immunomodulatory effect, namely the regulation of macrophage phenotypes. Using techniques involving enzymatic digestion and collagen crosslinking, dDMs can be converted into hydrogels that preserve growth factors, bioactive binding sites, and the fundamental structural and functional proteins of the ECM. Moreover, hydrogels have the benefit of being injectable and can be used in defect areas with irregular shapes when compared to three-dimensional porous scaffolds. The aim of this study is to develop an hydrogel matrix derived from decellularized rabbit dermal matrix dRDMs and assess its immunomodulatory capabilities for applications in tissue engineering and regenerative medicine. These dermal matrices (dDMs), mostly consisting of collagen, elastin, fibronectin, and laminin, offer advantages over other decellularized tissues regarding availability and adaptability. In addition, by combining the innate immunomodulatory characteristics of dDMs with the adjustable physical properties of hydrogels, we hypothesize that the developed hydrogel will promote a favorable immune response, potentially enabling an immunomodulatory environment. dRDM, obtained through a chemical decellularization, will be lyophilized and subsequently processed into hydrogels through a pepsin-mediated digestion, followed by pH neutralization and warming to 37 ºC to induce gelation. Since the immunomodulatory response may be conditioned by the hydrogel synthesis process, different collagen crosslinking strategies will be evaluated, including photo, thermal, and chemical approaches. Hydrogel formulations will be characterized in terms of rheological properties, microstructure, biocompatibility, and immune response. Immunological assessment will include analysis of cytokine profiles, macrophages polarization markers and immune-related genes.
- Going green and mimetic: new ECM-based hydrogel for meniscus regeneration using supercritical CO2-assisted decellularizationPublication . Ho, Chou I.; Rodrigues, Francisco A. P.; Reis, Mariana S.; Sousa, Clara; Ribeiro, Viviana P.; Oliveira, Ana L.; Costa, João B.Meniscal injuries and its subsequent progression to osteoarthritis represent a major clinical challenge, as current treatments often fail to achieve effective and complete functional restoration. An alternative regenerative approach is tissue engineering using decellularized extracellular matrix (dECM), which aims to restore meniscal structure and function. Porcine meniscus, an abundant byproduct of meat production, offers a readily available source for this purpose. Unlike conventional decellularization methods that are harsh, time-consuming, and detrimental to extracellular matrix (ECM) integrity, a detergent-free decellularization protocol utilizing supercritical carbon dioxide (scCO2) fluid was developed. This sustainable and minimally-invasive process was employed in cyclic pressurization-depressurization dynamics and scCO2 fluid was applied for sterilization by incorporating oxidative additives. Quantitative and qualitative analyses using quantification extraction kits and Fourier transform infrared (FTIR) spectroscopic analysis, presented as principal component analysis (PCA) and loading plots through a Machine Learning Toolbox, demonstrated substantial preservation of key ECM components. Sterilization efficiency was also confirmed using turbidity tests. dECM residual DNA content results fell within the range of general benchmark of 50ng/mg of dry tissue and the endotoxin levels, recently recognized as critical cause of host responds and regenerative outcomes [1], were below 20 endotoxin units (EU). The dECM showed cytocompatibility in vitro and an injectable hydrogel was successfully developed. The dECM hydrogel presented adhesive properties and was optimized to be used as a bioink for 3D bioprinting approaches.
- A novel ECM platform for skin regeneration: balancing structural integrity with low immunogenicityPublication . Rosadas, Marta; Sousa, Teresa; Sousa, Alda; Sánchez Espinel, Christian; Peleteiro, Mercedes; González-Fernández, África; Ribeiro, Viviana P.; Oliveira, Ana LeiteRabbit skin is an abundant agri-food by-product which can be up-cycled for generating xenogeneic extracellular matrix (ECM) scaffolds for skin tissue engineering, regeneration and modelling. When decellularized, rabbit dermis can preserve native collagen–elastin architecture and bioactive cues that support cell behaviour. However, decellularization parameters strongly influence ECM preservation, and trigger residual immunogenic components such as damage-associated molecular patterns (DAMPs). Decellularized rabbit dermal matrices (dRDMs) were produced using optimized chemical decellularization protocols and evaluated for decellularization efficiency, physicochemical properties and biochemical composition, using SEM, tensile testing, FTIR, proteomics, DNA, GAGs, collagen, and elastin quantification. Immunogenicity of dRDMs was assessed by endotoxin evaluation and using human peripheral blood mononuclear cells (PBMCs) to measure complement activation, ROS, apoptosis, activation markers and cytokines. dRDMs capacity to support human dermal fibroblasts (hDF) and keratinocytes (HaCaTs) adhesion and proliferation was assessed for 14 days, via Alamar Blue, BrdU, SEM, and DAPI/phalloidin staining. The dRDMs preserved native collagen and elastin networks. GAGs content was comparable to human dermis. DNA remained <50 ng/mg dry tissue, indicating efficient decellularization. No significant immune activation occurred: ROS and apoptosis were absent. PBMC activation matched controls with mild monocyte/B-cell responses. Cytokine profiles revealed modest inflammatory signaling with IL-10 production. Notably, lower DNA matrices induced stronger immune response, suggesting that biocompatibility depends on processing factors like detergent residues or DAMPs rather than DNA alone. In vitro, hDF and HaCaT viability and proliferation were maintained for 14 days on dRDM, supporting its potential for dermo-epidermal reconstruction in advanced co-culture models. Overall, dRDMs exhibited structural, biochemical, and immunological features supporting their potential as a robust dermal substrate for skin tissue engineering.
- Comparative in silico docking of bioactive peptides across the gut-skin axis: a systems approach to psoriasis modulation via the host-microbe interactionsPublication . Silva, Isa; Lambert, Jo L. W.; Pintado, Manuela; Coscueta, Ezequiel R.
- Effects of combining organic acid and essential oil as an alternative to replace potassium sorbate in fruit preparationsPublication . Melo, A.; Sorathiya, K.; Paulico, L.; Magalhães, I.; Hogg, M. C.; Pintado, M.The replacement of synthetic preservatives by natural alternatives is an increasing demand in the food industry, driven by consumer preference for clean-label products. This study investigated the substitution of potassium sorbate (PS) in red fruit preparations using combinations of propionic acid (PA) and lemongrass essential oil (LEO) with antimicrobial potential against fungi, yeasts, and bacteria, while maintaining safety and stability of the product. Six treatments were developed with different combinations of PA and LEO applied in concentrations ranging from minimum inhibitory concentration (MIC)/4 to 2 x MIC against Lactobacillus plantarum, Escherichia coli; Candida intermedia, Pichia fermentans, Aspergillus niger and Penicillium glabrum incorporated in red fruit preparation during 28 days. The systems were kept refrigerated (4 ± 2ºC) and counts were performed for each microorganism every 7 days. Inoculums of 105 and 102 spores/mL were used for fungi, 106 CFU/mL for bacteria and 103 CFU/mL for yeast. For all treatments, it was observed that there was no growth of any bacteria or yeast from the 1st day of the study. The 2 x MIC treatment inhibited fungal growth from day 7 onwards, followed by the MIC treatment, which inhibited fungi from day 14 onwards, with results similar to those of PS to A. niger (105 spores/mL), followed by the MIC/2 treatment which also inhibited P. glabrum (105 spores/mL) from the 7th day. All treatments completely inhibited the growth of both fungi with 102 spores/mL from 1st day (P. glabrum) or day 7 (A. niger), results similar to those of PS. These findings demonstrate the potential of replacing potassium sorbate with natural antimicrobial systems based on propionic acid and lemongrass essential oil in fruit-based products. Future work will focus on optimizing sensory attributes, assessing shelf-life performance, and evaluating the scalability of these formulations for industrial implementation.
- Development of an oleogel as a strategy to reduce saturated fats in biscuit filling creamPublication . Lima, Vasco; Vila-Real, Catarina; García-Guzmán, Andrea; Peixoto, Rita; Gomes, Ana MariaBackground: Food reformulation to improve the nutritional profile is a key strategy to promote balanced diets and offer additional benefits but the addition, substitution, or elimination of ingredients can affect functional and sensory properties. This work aimed to improve the nutritional profile of a biscuit filling cream, by creating an oleogel with reduced saturated fats. Methods: High-oleic sunflower oil was used as the liquid oil phase and two natural waxes (rice bran wax (RBW) and candelilla wax (CDW)) were tried as oleogelators at varied concentrations (2-14%). Oleogels were added sugar and cocoa powder to make the creams. Textural profile analysis, oil binding capacity (filter paper method) and microstructure (polarized light microscopy) of oleogels and creams were assessed. Total saturated fat content (gas chromatography with a flame ionization detector) was evaluated in experimental and commercial biscuits. Results: The hardness of filling creams, simple oleogel and oleogel with sugar was similar: as oleogelator’s concentration increases, oleogel’s hardness increases (not proportionally). 14% RBW (0.04%/h) and 10% CDW (0.03%/h) creams had the lowest oil migration rate, with a final oil loss <2% after 5 days for both. CDW oleogels had a feather and needle-like structure, forming a continuous network and RBW oleogels had a spherulitic structure without a continuous network. Micrographs of the oleogels with sugar showed white, shiny structures, while those with cocoa particles were brown, opaque and homogeneously distributed throughout the network. The most promisor cream was prepared with 14% RBW. Experimental biscuit’s saturated fat content was ~50% lower than commercial biscuit’s value (9.7 ± 0.7 g/ 100g vs. 19.9 ± 0.5 g/ 100g). Conclusions: The high unsaturated fat oleogel-based filling cream developed shows potential to replace traditional high saturated fat creams. This strategy helps enhance confectionery foods, offering health-conscious consumers indulgent, yet nutritious snacks.