Browsing by Author "Serra, Julia"
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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.
- Exploring new biobased material sources as platforms to advance skin wound healing and regenerationPublication . Ribeiro, Viviana; Bernardes, Beatriz G.; Duarte, Marta; Rosadas, Marta; Sousa, Teresa; Sousa, Alda; Serra, Julia; García-González, Carlos; Oliveira, Ana L.Chronic wounds are one of the major therapeutic and healthcare challenges affecting the population globally. One of the research interests of the Biomaterials and Biomedical Technology Lab (BBT Lab) is to explore the potential of biobased material platforms to advance skin wound healing and regeneration solutions. From the use of natural based biopolymers such as silk fibroin (SF) or sulfated exopolysaccharides (EPS), to the processing of more complex matrices such as the extracellular matrices, the group has been collaborating with some strategic partners in IBEROS+ to process, functionalize and characterize the materials for their physicochemical properties, structural adaptability, biocompatibility and bioactivity. SF microparticulate aerogels loaded with adenosine have been developed via supercritical fluid technology in collaboration with the University of Santiago de Compostela. These particles exhibit a high porosity, biocompatibility, and positive interactions with skin cells towards regeneration, highlighting their promise in wound healing. A new Exopolysaccharide (EPS) produced by Porphyridium cruentum microalgae was developed as a novel biomaterial platform, offering bioactive properties, high molecular weight, thermal stability, and cytocompatibility for complex wound healing. An extensive characterization is ongoing, with contribution of the University of Vigo. For extensive burn wounds, where autologous grafts are impractical, skin xenografts may provide a viable alternative, mostly if depleted from its immunogenic load. To achieve this, our group has developed and optimized methods for obtaining highly-preserved animal- origin decellularized tissues for human skin healing and regeneration. An important example is the valorization of rabbit skin, a valuable agro-food by-product that exceeds 5000 skins/day only in Europe. Our group has recently developed decellularized rabbit dermal matrices with preserved microarchitecture and human-like biochemical properties and expects to continue further developments in collaboration with the IBEROS+ consortium.