Percorrer por autor "Oliveira, Ana Leite"
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- 3D-printed PLA medical devices: physicochemical changes and biological response after sterilisation treatmentsPublication . Pérez-Davila, Sara; González-Rodríguez, Laura; Lama, Raquel; López-Álvarez, Miriam; Oliveira, Ana Leite; Serra, Julia; Novoa, Beatriz; Figueras, Antonio; González, PíoPolylactic acid (PLA) has become one of the most commonly used polymers in medical devices given its biocompatible, biodegradable and bioabsorbable properties. In addition, due to PLA’s thermoplastic behaviour, these medical devices are now obtained using 3D printing technologies. Once obtained, the 3D-printed PLA devices undergo different sterilisation procedures, which are essential to prevent infections. This work was an in-depth study of the physicochemical changes caused by novel and conventional sterilisation techniques on 3D-printed PLA and their impact on the biological response in terms of toxicity. The 3D-printed PLA physicochemical (XPS, FTIR, DSC, XRD) and mechanical properties as well as the hydrophilic degree were evaluated after sterilisation using saturated steam (SS), low temperature steam with formaldehyde (LTSF), gamma irradiation (GR), hydrogen peroxide gas plasma (HPGP) and CO2 under critical conditions (SCCO). The biological response was tested in vitro (fibroblasts NCTC-929) and in vivo (embryos and larvae wild-type zebrafish Danio rerio). The results indicated that after GR sterilisation, PLA preserved the O:C ratio and the semi-crystalline structure. Significant changes in the polymer surface were found after HPGP, LTSF and SS sterilisations, with a decrease in the O:C ratio. Moreover, the FTIR, DSC and XRD analysis revealed PLA crystallisation after SS sterilisation, with a 52.9% increase in the crystallinity index. This structural change was also reflected in the mechanical properties and wettability. An increase in crystallinity was also observed after SCCO and LTSF sterilisations, although to a lesser extent. Despite these changes, the biological evaluation revealed that none of the techniques were shown to promote the release of toxic compounds or PLA modifications with toxicity effects. GR sterilisation was concluded as the least reactive technique with good perspectives in the biological response, not only at the level of toxicity but at all levels, since the 3D-printed PLA remained almost unaltered.
- 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.
- 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.
- Chitosan/collagen biomembrane loaded with 2,3-dihydrobenzofuran for the treatment of cutaneous LeishmaniasisPublication . Braz, Elton Marks Araujo; Silva, Solranny Carla Cavalcante Costa; Alves, Michel Muálem Moraes; Carvalho, Fernando Aécio Amorim; Magalhães, Rui; Osajima, Josy Anteveli; Silva, Durcilene Alves; Oliveira, Ana Leite; Muniz, Edvani Curti; Silva-Filho, Edson CavalcantiIn this work, chitosan/collagen-based membranes loaded with 2,3-dihydrobenzofuran (2,3-DHB) were developed through a simple solvent-casting procedure for use in the treatment of cutaneous Leishmaniasis. The obtained membranes were characterized by elemental analysis, FTIR, TG, DSC, and XRD. Porosity, swelling, mechanical properties, hydrophilicity, and antioxidant activity were analyzed. In addition, assessment to the biocompatibility, through fibroblasts/keratinocytes and in vitro wound healing essays were performed. The obtained results show that the new 2,3-DHB loaded chitosan/collagen membrane presented high porosity and swelling capacity as well as maximum strength, hydrophilicity, and antioxidant activity higher in relation to the control. The tests of antileishmanial activity and the AFM images demonstrate great efficacy of inhibition growth of the parasite, superior to those from the standard therapeutic agent that is currently used: Amphotericin B. The new membranes are biocompatible and stimulated the proliferation of keratinocytes. SEM images clearly demonstrate that fibroblasts were able to adhere, maintained their characteristic morphology. The healing test evidenced that the membranes have adequate environment for promoting cell proliferation and growth. As the conventional treatments often use drugs with high toxicity, the as-developed new membranes proved to be excellent candidate to treat cutaneous Leishmaniasis and can be clearly indicated for further advanced studies in vivo.
- Coaxial 3D printing: synergistic approach of natural and synthetic biomaterials for knee meniscus replacementPublication . Rodrigues, Francisco A. P.; Araújo, Marco; Granja, Pedro L.; Oliveira, Ana Leite; Costa, João B.
- 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.
- 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.
- 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.