Browsing by Author "Dias, Juliana R."
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- Continuous production of highly tuned silk/calcium-based composites: exploring new pathways for skin regenerationPublication . Veiga, Anabela; Magalhães, Rui; Duarte, Marta M.; Dias, Juliana R.; Alves, Nuno M.; Costa-Pinto, Ana Rita; Castro, Filipa; Rocha, Fernando; Oliveira, Ana L.Calcium plays an important role in barrier function repair and skin homeostasis. In particular, calcium phosphates (CaPs) are well established materials for biomedical engineering due to their biocompatibility. To generate biomaterials with a more complete set of biological properties, previously discarded silk sericin (SS) has been recovered and used as a template to grow CaPs. Crucial characteristics for skin applications, such as antibacterial activity, can be further enhanced by doping CaPs with cerium (Ce) ions. The effectiveness of cell attachment and growth on the materials highly depends on their morphology, particle size distribution, and chemical composition. These characteristics can be tailored through the application of oscillatory flow technology, which provides precise mixing control of the reaction medium. Thus, in the present work, CaP/SS and CaP/SS/Ce particles were fabricated for the first time using a modular oscillatory flow plate reactor (MOFPR) in a continuous mode. Furthermore, the biological behavior of both these composites and of previously produced pure CaPs was assessed using human dermal fibroblasts (HDFs). It was demonstrated that both CaP based with plate-shaped nanoparticles and CaP-SS-based composites significantly improved cell viability and proliferation over time. The results obtained represent a first step towards the reinvention of CaPs for skin engineering.
- Editorial: advances in biofabrication for skin regenerationPublication . Dias, Juliana R.; Longoni, Alessia; Oliveira, Ana L.
- In situ enabling approaches for tissue regeneration: current challenges and new developmentsPublication . Dias, Juliana R.; Ribeiro, Nilza; Baptista-Silva, Sara; Costa-Pinto, Ana Rita; Alves, Nuno; Oliveira, Ana. L.In situ tissue regeneration can be defined as the implantation of tissue-specific biomaterials (by itself or in combination with cells and/or biomolecules) at the tissue defect, taking advantage of the surrounding microenvironment as a natural bioreactor. Up to now, the structures used were based on particles or gels. However, with the technological progress, the materials’ manipulation and processing has become possible, mimicking the damaged tissue directly at the defect site. This paper presents a comprehensive review of current and advanced in situ strategies for tissue regeneration. Recent advances to put in practice the in situ regeneration concept have been mainly focused on bioinks and bioprinting techniques rather than the combination of different technologies to make the real in situ regeneration. The limitation of conventional approaches (e.g., stem cell recruitment) and their poor ability to mimic native tissue are discussed. Moreover, the way of advanced strategies such as 3D/4D bioprinting and hybrid approaches may contribute to overcome the limitations of conventional strategies are highlighted. Finally, the future trends and main research challenges of in situ enabling approaches are discussed considering in vitro and in vivo evidence.
- Streamlining skin regeneration: a ready-to-use silk bilayer wound dressingPublication . Veiga, Anabela; Silva, Inês V.; Dias, Juliana R.; Alves, Nuno M.; Oliveira, Ana L.; Ribeiro, Viviana P.Silk proteins have been highlighted in the past decade for tissue engineering (TE) and skin regeneration due to their biocompatibility, biodegradability, and exceptional mechanical properties. While silk fibroin (SF) has high structural and mechanical stability with high potential as an external protective layer, traditionally discarded sericin (SS) has shown great potential as a natural-based hydrogel, promoting cell–cell interactions, making it an ideal material for direct wound contact. In this context, the present study proposes a new wound dressing approach by developing an SS/SF bilayer construct for full-thickness exudative wounds. The processing methodology implemented included an innovation element and the cryopreservation of the SS intrinsic secondary structure, followed by rehydration to produce a hydrogel layer, which was integrated with a salt-leached SF scaffold to produce a bilayer structure. In addition, a sterilization protocol was developed using supercritical technology (sCO2) to allow an industrial scale-up. The resulting bilayer material presented high porosity (>85%) and interconnectivity while promoting cell adhesion, proliferation, and infiltration of human dermal fibroblasts (HDFs). SS and SF exhibit distinct secondary structures, pore sizes, and swelling properties, opening new possibilities for dual-phased systems that accommodate the different needs of a wound during the healing process. The innovative SS hydrogel layer highlights the transformative potential of the proposed bilayer system for biomedical therapeutics and TE, offering insights into novel wound dressing fabrication.
- Ultrasound sonication prior to electrospinning tailors silk fibroin/PEO membranes for periodontal regenerationPublication . Serôdio, Ricardo; Schickert, Sónia L.; Costa-Pinto, Ana R.; Dias, Juliana R.; Granja, Pedro L.; Yang, Fang; Oliveira, Ana L.In this study, silk fibroin (SF)/poly(ethylene oxide) (PEO) membranes were designed and fabricated by combining ultrasound sonication prior to electrospinning (0 to 20 min) as a strategy to physically control the rheological properties of solutions (10 to 30% w/v PEO) and to improve the spinnability of the system. PEO has proved to be essential as a co-spinning agent to assure good membrane reproducibility and enough flexibility for clinical manipulation. The rheological tests indicated that sonication greatly increased the viscosity of SF/PEO solutions and further enhanced the quality of the produced electrospun fibers with consequent improved mechanical properties in dry and wet conditions. By tuning the viscosity of the solutions using a simple sonication step prior to electrospinning, it was possible to induce water stability in the as-electrospun matrix, as demonstrated by infra-red spectroscopy. This reduced complexity in the process since it was not necessary to concentrate silk prior to electrospinning while avoiding the use of toxic solvents to perform a post-processing stabilization treatment which usually causes dimensional changes to the SF materials. Sonication pre-treatment allowed for minimizing the amount of synthetic polymer used to achieve the desirable mechanical properties (with the modulus ranging between 90 and 170 MPa), while avoiding a further water stabilization treatment. It also had a positive impact in the in vitro cell behavior of human primary periodontal ligament cells (hPDLs), resulting in a marked increase in cell proliferation. The present developed work constitutes a step forward towards simplicity and a better fabrication control of viable electrospun SF-based membranes for periodontal regeneration.