Percorrer por autor "Bernardes, Beatriz G."
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- Adenosine-loaded silk fibroin aerogel particles for wound healingPublication . Bernardes, Beatriz G.; Rossa, Valentina; Silva, Sara Baptista da; Magalhães, Rui; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana LeiteThe healing process of an injury comprises a series of steps (haemostasis, inflammation and proliferation/maturation). Exudate from wounds is a natural response to heal. However, an excess production can compromise and delay the inflammatory phase, resulting in chronicity. Novel biocompatible, biodegradable and adaptable dressings are sought to promote tissue regeneration, prevent infection and control inflammation. Aerogels are nanostructured dry materials with high porosity, large surface and low bulk density. Bio-based aerogels, from natural polymer sources, can provide advanced performance for wound healing; also, they can act as carriers for bioactive compounds.[1] Adenosine (ADO) is a nucleoside that is expected to trigger the healing process of chronic wounds, promoting angiogenesis and regeneration.[2] Silk fibroin (SF) aerogels can act as promising carriers of bioactive molecules while supporting cell proliferation. Hereupon, SF aerogels loaded with Adenosine were developed in the form of particles for wound healing applications, using supercritical CO2 technology.
- Adenosine-loaded silk fibroin aerogel particles for wound healingPublication . Bernardes, Beatriz G.; Rossa, Valentina; Baptista-Silva, Sara; Magalhães, Rui; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana LeiteChronic wounds are one of the major therapeutic and healthcare challenges. A natural healing response is the production of exudate from a wound. However, its overproduction can compromise and delay the inflammatory phase, resulting in chronicity. Bio-based aerogels, from natural polymer sources, can provide advanced performance for wound healing due to their high porosity and large surface area, which can be tailored for a fast and directional fluid transfer of the exudate; also, they can act as carriers for bioactive compounds. Silk fibroin (SF) protein is an excellent carrier of bioactive compounds while supporting cell proliferation, being presently used in wound healing and regeneration. In this work, we propose the use supercritical CO2 technology to develop SF aerogel particles as a controlled release system of adenosine, a protein that is herein proposed for the first time being expected to trigger the healing process of chronic wounds, promoting angiogenesis and regeneration. For the aerogel particles’ production, SF aqueous solutions at different concentrations (3, 5 and 7 %(w/v)) loaded with adenosine at different ratios were dispersed in a solution of ethanol/Span 80 (3 wt.% with respect to SF), followed by supercritical CO2 drying (120 bar, 39ºC, 3.5 h). Physico-chemical characteristics, drug release and cytotoxicity activity of bioactive SF particles will be explored.
- Adenosine-loaded silk fibroin: a promising approach for chronic wound healing and regenerationPublication . Bernardes, Beatriz G.; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana L.Introduction: Chronic wounds are one of the major therapeutic and healthcare challenges affecting the population globally. During the healing stage of a wound the production of exudate is considered as a normal process. However, its overproduction can compromise and delay the inflammatory phase, contributing to wound chronicity. Aerogels are highly porous materials which can provide advanced performance for wound healing, as they can be tailored for a fast and directional fluid transfer of the exudate; also, they can have a therapeutic function, as carriers for bioactive compounds. Silk fibroin (SF) protein is well known to stabilize bioactive molecules and therapeutic drugs while supporting cell proliferation, being presently used in wound healing and regeneration. In this work, we propose the use supercritical CO2 technology to develop SF aerogel particles as a controlled release system of adenosine (ADO). This nucleoside is herein proposed for the first time, being expected to trigger the healing and regeneration of chronic wounds. Methods: Development of aerogel particles SF aqueous solutions at different concentrations (3, 5 and 7% (w/v)) loaded with ADO at different weight ratios (10:1, 5:1, 2:1), were introduced into absolute ethanol and Span 80 followed by supercritical CO2 drying (Figure 1). Scanning Electron Microscopy (SEM) was used to analyze the morphology of the particles and to visualize their interaction with; laser diffraction was performed to determine particles diameter. The biocompatibility was assessed using three types of cells that play an important role during wound healing, human dermal fibroblasts (HDF), human immortalized keratinocytes (HaCaT) and human dermal microvascular endothelial cells (HDMEC). The interaction between ADO-loaded SF aerogel particles was assessed by viability and proliferation assays. Quantitative data were subjected to an analysis of variance (one-way ANOVA, Tukey’s test; α=0.05). Conclusions: The microparticles showed favorable morphological properties and supported cell proliferation and biocompatibility, with drug release tests indicating rapid adenosine release. Ongoing assays with HDMEC indicate favorable cell behavior, providing insights into their angiogenic properties. Future work involves optimizing formulations for enhanced therapeutic efficacy and exploring clinical applications in chronic wound management and tissue regeneration.
- Automated high-throughput microscopy screening unveiled new Listeria monocytogenes genes involved in cell infectionPublication . Alves, Ângela; Meireles, Diana; Suriano, Chiara; Monteiro, Ricardo; Oliveira, Rute; Bernardes, Beatriz G.; Sousa, Sandra; Pombinho, Rita; Cabanes, DidierTo uncover novel genetic factors required for Listeria monocytogenes cell infection, we developed an automated high-throughput microscopy screening pipeline that integrates GFP-expressing bacteria with machine learning-based image analysis. Using this approach, we screened a mariner transposon library comprising 4,224 L. monocytogenes EGDe mutants and identified 58 with significantly reduced numbers of intracellular bacteria. Sequencing revealed 24 unique insertion sites corresponding to 14 genes, including previously known virulence factors and nine novel candidates not previously implicated in cell infection. These genes encode the protease chaperone ClpX, the ferric uptake regulator Fur, the sensor histidine kinase LisK, the peptide chain release factor 2 PrfB, proteins involved in proline and purine biosynthesis (ProAB, PurAB), and Lmo2217, a protein of unknown function. Among these, the targeted deletion of the adenylosuccinate synthetase gene, purA, resulted in impaired growth in minimal medium, severely reduced proliferation in epithelial and macrophage cell lines, and attenuated virulence in mice. Unexpectedly, PurA was also essential for bacterial internalization into cells. Supplementation with AMP or adenine, but not ATP, rescued the invasion capacity of the ?purA mutant. Mechanistically, purA deletion induced a reduction in the levels of surface-associated GAPDH, a putative plasminogen-binding protein, likely contributing to the observed invasion defect. Overall, these findings highlight the power of automated high-throughput microscopy screening to dissect host–pathogen interactions, identify novel L. monocytogenes genes required for cell infection, and uncover an unexpected role for PurA in maintaining GAPDH surface localization and promoting bacterial entry into host cells.
- Bioaerogels: promising nanostructured materials in fluid management, healing and regeneration of woundsPublication . Bernardes, Beatriz G.; Gaudio, Pasquale del; Alves, Paulo; Costa, Raquel; García-Gonzaléz, Carlos A.; Oliveira, Ana LeiteWounds affect one’s quality of life and should be managed on a patient-specific approach, based on the particular healing phase and wound condition. During wound healing, exudate is produced as a natural response towards healing. However, excessive production can be detrimental, representing a challenge for wound management. The design and development of new healing devices and therapeutics with improved performance is a constant demand from the healthcare services. Aerogels can combine high porosity and low density with the adequate fluid interaction and drug loading capacity, to establish hemostasis and promote the healing and regeneration of exudative and chronic wounds. Bio-based aerogels, i.e., those produced from natural polymers, are particularly attractive since they encompass their intrinsic chemical properties and the physical features of their nanostructure. In this work, the emerging research on aerogels for wound treatment is reviewed for the first time. The current scenario and the opportunities provided by aerogels in the form of films, membranes and particles are identified to face current unmet demands in fluid managing and wound healing and regeneration.
- Design and characterization of biopolymer-based core–shell particles for sustained release of adenosine in tissue regenerationPublication . Bernardes, Beatriz G.; Sousa, Clara; Sellitto, Maria Rosaria; Iglesias-Mejuto, Ana; Gaudio, Pasquale del; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana Leite
- Design and characterization of biopolymer-based core–shell particles for sustained release of adenosine in tissue regenerationPublication . Bernardes, Beatriz G.; Sousa, Clara; Sellitto, Maria Rosaria; Iglesias-Mejuto, Ana; Gaudio, Pasquale del; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana LeiteThe treatment of chronic wounds remains a formidable challenge in regenerative medicine, necessitating multifunctional biomaterials capable of modulating inflammation, promoting angiogenesis, and enabling sustained drug delivery [1]. This study presents a novel class of core–shell aerogel particles engineered from silk fibroin (SF), silk sericin (SS), and alginate (ALG), designed for the controlled release of adenosine (ADO)—a nucleoside with anti-inflammatory and pro-regenerative properties [2]. Using coaxial prilling and supercritical CO? drying, two architectures were fabricated: SF/ALG cores enveloped by ALG or ALG/SS shells.
- Development of self-assembled aerogel silk particles for wound healingPublication . Bernardes, Beatriz G.; Baptista-Silva, Sara; Illanes-Bordomás, Carlos; Magalhães, Rui; Costa, Raquel; García-González, Carlos A.; Oliveira, Ana Leite
- Dual and sequential drug delivery systems with antimicrobial and bone regenerative therapeutic effectsPublication . Rodrigues, Miguel A.; Ferreira, Carla; Borges, João P.; Bernardes, Beatriz G.; Oliveira, Ana L.; Santos, José D.; Lopes, Maria A.Bone defect healing is often compromised by infections acquired during surgery, hindering regeneration. An effective solution should first prevent infection and then promote bone repair. Localised drug-delivery systems capable of dual and sequential release of antimicrobial and bone-regenerative agents represent a promising solution; however, precisely controlling this sequential release remains an unmet challenge. To address this issue, this study explores a novel approach by developing delivery systems based on either hollow or non-hollow porous bioceramics with an alginate hydrogel matrix, resulting in cutting-edge systems with a controlled, stage-specific release of antimicrobial and bone regenerative agents that meet the clinical needs. Gentamicin served as the antimicrobial agent, while raloxifene and/or alendronate represented hydrophobic and hydrophilic bone-regenerative agents. The systems were evaluated for release profiles, kinetic modelling, and the effects of lyophilisation and sterilisation (using ethylene oxide or supercritical CO2) on drug stability and release kinetics. The release followed a precise dual-sequential pattern: gentamicin was released over 2–3 weeks, followed by another 2–3 weeks of bone-regenerative agents. Kinetic model fitting showed that gentamicin release was driven mainly by diffusion (with or without hydrogel swelling), and raloxifene/alendronate release was dominated by a mixture of diffusion and polymeric matrix swelling/erosion. Lyophilisation and sterilisation preserved release profiles, though timeframes shifted slightly, with supercritical CO2 causing minimal delay. Gentamicin retained strong antimicrobial activity post-processing, confirming the system's potential for infection control and bone repair.
- Eucalyptus-enhanced cotton: pretreatment and bioactive coating strategies for the development of sustainable textiles with antimicrobial and antioxidant activities for skin applicationsPublication . Oliveira, Cláudia S.; Costa, Ana; Mendanha, Daniel; Macedo, Tiago; Moreira, Joana; Oliveira, Juliana A. S. A.; Bernardes, Beatriz G.; Silva, Carla J.; Tavaria, Freni K.Eucalyptus essential oils and extracts are widely recognized for their antimicrobial, antioxidant, insecticidal, anti-inflammatory, and aromatizing properties, making them highly valuable across pharmaceuticals, cosmetics, and textiles. For the design of biomedical textiles, cotton is favored for its mechanical strength, porosity, and biodegradability, but its vulnerability to microbial action limits its applications. To address this issue, natural compounds like eucalyptus essential oils and extracts have been prioritized over synthetic agents to enhance their antimicrobial properties. While bioactive textiles using essential oils have been well-documented, the incorporation of eucalyptus leaf extracts with different surface modifications of cotton remains largely unexplored. In this line, this study investigated pretreatment approaches to improve the uptake and uniformity of eucalyptus extract on cotton fibers. To achieve this, chitosan (CH), a cationic agent, and alum were applied to the cotton fabric to promote stronger electrostatic interactions and improve the binding of extract’s bioactive components. The functionalized fabrics were tested for antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli, antioxidant properties, and cytotoxicity using human keratinocytes. Eucalyptus-functionalized cotton, particularly with CH pretreatment, exhibited strong antibacterial activity against Gram-positive bacteria and enhanced antioxidant capacity in the DPPH assay. No cytotoxicity was detected with 8 h of exposure, but potential effects were observed after 24 h, indicating the need for further evaluation of long-term safety. These findings highlight the potential of eucalyptus-functionalized textiles for personalized clothing aimed at managing skin conditions linked to microbiota dysregulation, emphasizing the need for optimized functionalization and biocompatibility evaluation.
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