Browsing by Author "Oliveira, A. L."
Now showing 1 - 10 of 13
Results Per Page
Sort Options
- Aplicação de um hidrogel de sericina em feridas crónicas de animais com diabetes tipo 2Publication . Costa, R.; Silva, S. B.; Rodrigues, I.; Soares, R.; Oliveira, A. L.
- Bioinspired silk microparticles loaded with adenosine: advanced therapeutics for targeting chronic wound healingPublication . Bernardes, B. G.; Laurano, R.; Costa, R.; Oliveira, A. L.; García-González, C. A.Chronic wound healing is a complex process often associated with excessive exudate production, which can prolong inflammation and raise infection risk due to polymicrobial microflora. Current wound dressings often lack efficient absorption kinetics, leading to tissue maceration and discomfort, while patient pain and inflammation management persist [1]. Aerogels, characterized by high porosity and large surface area, offer promising solutions for wound care. Bio-based aerogels, particularly those derived from natural polymers, show potential in facilitating fluid transfer and acting as carriers for bioactive compounds, thereby aiding inflammation control and infection prevention. Silk-based biomaterials have emerged as promising candidates for drug and cell delivery due to their biocompatibility, low toxicity, and customizable drug-release capabilities [2,3]. In this work we have developed new silk fibroin (SF) microparticulate aerogels loaded with Adenosine (ADO) using supercritical fluid technology, to create a drug carrier system targeting chronic wound healing to address the inflammatory stage and angiogenic properties. ADO is a nucleoside known for its ability to promote angiogenesis and tissue regeneration [4]. Various concentrations of SF (3%, 5%, and 7% w/v) and different ratios of ADO were employed for particle production. The resultant particles exhibited favorable characteristics, including high porosity (93% to 94%), an envelope density spanning 0.07 to 0.11 g/cm3, skeletal density falling between 1.22 and 1.31 g/cm3, and a surface area ranging from 191 to 306 m2/g. The drug release tests revealed that approximately 80% of adenosine was released within 30 minutes. In vitro tests were conducted using keratinocytes (HaCaT), primary fibroblasts (HDF), and endothelial (HDMEC) cells, all of which are critical to the wound healing and regeneration process. These cells contribute to the deposition of new matrix, blood vessels, and skin tissue repair. Cell viability and proliferation assays demonstrated the biocompatibility of all particle formulations with HDF and HaCaT cells (Figure 1). However, some differences were observed in the cellular interactions. Specifically, HDF exhibited favorable interaction with the particles on day 1, whereas HaCaT cells demonstrated a range of different behaviors. This variance may be linked to the superior performance of HDF over HaCaT cells when exposed to adenosine solutions within the concentration range of 0.1 – 2 mg/mL. HDMEC assays are currently underway, with preliminary findings indicating that adenosine-containing particles exhibit favorable cell biocompatibility. CAM assay is presently ongoing to evaluate the blood vessel formations in a live system. In conclusion, the microparticles showed favorable morphological properties and supported cell proliferation and biocompatibility, with drug release tests indicating rapid adenosine release. Ongoing assays with HDMEC suggest favorable cell behaviour, particularly when adenosine, in line with its ability to promote angiogenesis. Future work involves optimizing formulations for enhanced therapeutic efficacy and exploring clinical applications in chronic wound management and tissue regeneration.
- Biomechanical performance of hybrid electrospun structures for skin regenerationPublication . Dias, J. R.; Baptista-Silva, S.; Sousa, A.; Oliveira, A. L.; Bártolo, P. J.; Granja, P. L.Wound dressings made by electrospun nanofibers have been demonstrating great potential to regenerate skin tissue as compared to the conventional membrane products available in the market. Until today most of the developed dressings have only demonstrated the capability to regenerate the dermis or epidermis. In this study we propose new hybrid electrospun meshes combining polycaprolactone and gelatin. Several approaches, multilayer, coating and blend were stablished to investigate the most appropriate hybrid structure with potential to promote skin regeneration in its full thickness. The structures were evaluated in terms of physico-chemical properties (porosity, water vapor permeability, contact angle and swelling degree) and according to its mechanical and biological performance. Multilayer and blend structures demonstrated to fit most of native skin requirements. However, looking to all the performed characterization we considered multilayer as the most promising hybrid structures, due its high porosity which contributed to an ideal water vapor permeability rate and good mechanical and biological properties. Based on this multilayer structure is a promisor wound dressing.
- Chondrogenic effect of kartogenin on an immortalized cell line derived from mesenchymal stromal cells isolated from human bone marrowPublication . Guiance-Varela, C.; Rodríguez-Pereira, C.; Burguera, E. F.; Hermida-Gómez, T.; Goyanes, N.; Oliveira, A. L.; Blanco, F. J.; Magalhaes, J.
- Complex 3D architectures using a textile technology for bone tissue engineering applicationsPublication . Ribeiro, V. P.; Ribeiro, A. S.; Silva, C. J.; Durães, N. F.; Bonifácio, G.; Correlo, V. M.; Marques, A. P.; Sousa, R. A.; Oliveira, A. L.; Reis, R. L.Textile-based technologies are particularly interesting in tissue engineering since they allow producing finely tuned fibre-based porous structures, offering superior control over the material design (size, porosity, fibre alignment) and manufacturing. Scaffolds with very reproducible and interconnected intra-architectural geometry can be processed increasing the surface area for cell attachment and tissue ingrowth. This work aims to evaluate the potential of recently developed 3D textile structures based on silk fibroin (SF) to support human Adipose-derived Stem Cells (hASCs) adhesion, proliferation and osteogenic differentiation. These cells constitute an emerging possibility for regenerative medicine, including for bone tissue regeneration. A comparative analysis was performed with a more stable polymeric system, polyethylene terephthalate (PET). SF and PET yarns were processed into 3D spacer structures using warp-knitting technology. The obtained complex 3D architectures are composed of two knitted layers assembled/spaced by a PET monofilament to increase the tri-dimensionality of the scaffold. Cells were able to attach to the fibres, proliferate and differentiate into the osteogenic lineage. hASCs were able to deeply penetrate into the scaffold and colonize its interior with great evidences of extracellular matrix mineralization (Fig.1). The efficiency and high level of control of the warpknitting technology together with the interesting structural properties of the resulting constructs makes this a very versatile and adaptable system to the specific bone tissue anatomy and function.
- Decellularized small intestine for burn wound treatment: a tissue engineering paradigm shift?Publication . Silva, I. V. M.; Rosadas, M.; Duarte, M.; Rodrigues, I.; Ribeiro, V.; Costa, R.; Oliveira, A. L.Burn injuries are a major global health concern, estimated to cause 11 million injuries and 180,000 fatalities annually (1). The morbidity of burn injuries extends beyond the physical trauma, resulting in microorganism invasion, infection, and sepsis (1). Moreover, burn scars can compromise the quality of life, affecting joint mobility, functionality, and daily activities (2,3). Conventional dressings and autografts face limitations in healing, requiring the emergence of novel strategies (4). Xerographic tissue, after the adequate decellularization processing to cope with the low immunogenicity requirements, represents a unique avenue for developing advanced wound dressings. Porcine small intestine is characterized by its composition of fibroblast growth factors, transforming growth factor-beta, vascular endothelial growth factor, and structural and functional proteins. These components play pivotal roles in wound healing, regulating cell division, migration, and differentiation (5). To fully preserve these important bioactive molecules while ensuring its cost-effectiveness is an essential task, that can only be achieved by adequately designing tissue specific decellularization processes. This work proposes an advanced decellularization pipeline to obtain a safe and highly preserved porcine small intestine decellularized ECM, using combinatorial approaches and advanced technologies to achieve optimal tissue functionality as a wound dressing.
- Evaluation of novel 3D architectures based on knitting technologies for engineering biological tissuesPublication . Ribeiro, V. P.; Ribeiro, A. S.; Silva, J. C.; Durães, N. F.; Bonifácio, G.; Correlo, V. M.; Marques, A. P.; Sousa, R. A.; Oliveira, A. L.; Reis, R. L.Textile-based technologies are considered as potential routes for the production of 3D porous architectures for tissue engineering applications. We describe the use of two polymers, namely polybutylene succinate (PBS) and silk fibroin (SF) to produce fiber-based finely tuned porous architectures by weft and warp knitting. The obtained knitted constructs are described in terms of their morphology, mechanical properties, swelling ability, degradation behaviour and cytotoxicity. Each type of polymer fibers allow for the processing of a very reproducible intra-architectural scaffold geometry, with distinct characteristics in terms of the surface physicochemistry, mechanical performance and degradation capability, which has an impact on the resulting cell behaviour at the surface of the respective biotextiles. Preliminary cytotoxicity screening shows that both materials can support cell adhesion and proliferation. Furthermore, different surface modifications were performed (acid/alkaline treatment, UV radiation and plasma) for modulating cell behavior. An increase of cell- material interactions were observed, indicating the important role of materials surface in the first hours of culturing. Human Adipose-derived Stem Cells (hASCs) became an emerging possibility for regenerative medicine and tissue replacement therapies. The potential of the recently developed silk- based biotextile structures to promote hASCs adhesion, proliferation and differentiation is also evaluated. The obtained results validate the developed constructs as viable matrices for TE applications. Given the processing efficacy and versatility of the knitting technology, and the interesting structural and surface properties of the proposed polymer fibers, it is foreseen that our developed systems can be attractive for the functional engineering of tissues such as bone, skin, ligaments or cartilage and also for develop more complex systems for further industrialization of TE products.
- In situ antioxidant activity of an enzymatically crosslinked sericin hydrogel for healing of chronic woundsPublication . Bernardes, B. G.; Baptista-Silva, S.; Borges, S.; Pintado, M.; Granja, P. L.; Soares, R.; Costa, R.; Oliveira, A. L.
- In situ antioxidant activity of an enzymatically crosslinked sericin hydrogel towards chronic wound healingPublication . Bernardes, B. G.; Baptista-Silva, S.; Borges, S.; Pintado, M.; Granja, P. L.; Soares, R.; Costa, R.; Oliveira, A. L.
- In vitro evaluation of the biological performance of macro/ micro-porous silk fibroin and silk-nano calcium phosphate scaffoldsPublication . Yan, L.-P.; Oliveira, J. M.; Oliveira, A. L.; Reis, R. L.This study evaluates the biological performance of salt-leached macro/microporous silk scaffolds (S16) and silk-nano calcium phosphate scaffolds (SC16), both deriving from a 16 wt % aqueous SF solution. Enzymatic degradation results showed that the silk-based scaffolds presented desirable biostability, and the incorporation of calcium phosphate further improved the scaffolds' biostability. Human adipose tissue derived stromal cells (hASCs) were cultured onto the scaffolds in vitro. The Alamar blue assay and DNA content revealed that both scaffolds were non-cytotoxic and can support the viability and proliferation of the hASCs. Scanning electron microscopy observation demonstrated that the microporous structure was beneficial for the cell adhesion while the macroporous structure favored the cell migration and proliferation. The histological analysis displayed abundant extracellular matrix formed inside the scaffolds, leading to the significant increase of scaffolds' modulus. These results revealed that S16 and SC16 could be promising alternatives for cartilage and bone tissue engineering scaffolding applications, respectively.