Browsing by Author "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.
- Detergent-free supercritical CO2–assisted protocol for the production of sustainable and highly preserved decellularized porcine meniscus for orthopedic applicationsPublication . Ho, Chou I.; Rodrigues, Francisco A. P.; Reis, Mariana S.; Ribeiro, Viviana P.; Oliveira, Ana Leite; Costa, João B.Introduction & Objectives Meniscal injuries occur approximately 66 to 70 per 100,000 individuals annually (Fig. 1), potentially leading to the development of osteoarthritis (OA) or other degenerative cartilage disease in 10 to 20 years. One of the conventional treatments is meniscal allograft transplantation. However, its limitations constrain its comprehensive application in the healthcare system.
- Detergent-free supercritical CO2–assisted protocol for the production of sustainable and highly preserved decellularized porcine meniscus for orthopedic applicationsPublication . Ho, Chou I.; Rodrigues, Francisco A. P.; Reis, Mariana S.; Ribeiro, Viviana P.; Oliveira, Ana Leite; Costa, João B.
- Development of composite scaffolds based on cerium doped-hydroxyapatite and natural gums-biological and mechanical propertiesPublication . Santos, Marcus Vinicius Beserra dos; Rocha, Lorenna Bastos Nogueira; Vieira, Ewerton Gomes; Oliveira, Ana Leite; Lobo, Anderson Oliveira; Carvalho, Maria Acelina Martins de; Osajima, Josy Anteveli; Silva-Filho, Edson CavalcantiHydroxyapatite (HAp) is a ceramic material composing the inorganic portion of bones. Ionic substitutions enhance characteristics of HAp, for example, calcium ions (Ca2+) by cerium ions (Ce3+). The use of HAp is potentialized through biopolymers, cashew gum (CG), and gellan gum (GG), since CG/GG is structuring agents in the modeling of structured biocomposites, scaffolds. Ce-HApCG biocomposite was synthesized using a chemical precipitation method. The obtained material was frozen (–20 °C for 24 h), and then vacuum dried for 24 h. The Ce-HApCG was characterized by X-Ray diffractograms (XRD), X-ray photoemission spectra (XPS), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS). XRD and FTIR showed that Ce-HApCG was successfully synthesized. XRD showed characteristic peaks at 2θ = 25.87 and 32.05, corresponding to the crystalline planes (0 0 2) and (2 1 1), respectively, while phosphate bands were present at 1050 cm−1 and 1098 cm−1, indicating the success of composite synthesis. FESEM showed pores and incorporated nanostructured granules of Ce-HApCG. The mechanical test identified that Ce-HApCG has a compressive strength similar to the cancellous bone’s strength and some allografts used in surgical procedures. In vitro tests (MTT assay and hemolysis) showed that scaffold was non-toxic and exhibited low hemolytic activity. Thus, the Ce-HApCG has potential for application in bone tissue engineering.
- 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