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- Produção de Scaffolds de β-TCP/Alginato para uso na Regeneração Óssea por Prototipagem RápidaPublication . Carlos, Gabriela Soares Diogo; Correia, Ilídio Joaquim SobreiraThe rise of bone defects in the last decades has become a worldwide problem. They can arise from several causes such as tumors, trauma, infection, nutrition and bone diseases. This may compromise the mechanical and biological functions of bone tissue. Autografts, allografts and xenografts are some attractive alternatives used for bone tissue regeneration, however, several factors such as high risk of infection, immunogenic response and lack of donor has limited their use. In this context, Tissue Engineering appears as a promising solution. Tissue Engineering is an interdisciplinary area that combines biomaterials and bioactive molecules to promote the repair and regeneration of bone. Scaffolds are 3D matrices that act as temporary templates, allowing cell adhesion and proliferation and providing mechanical support until new bone tissue formation. A 3D scaffold success depends on their chemical, mechanical and biological properties. Rapid prototyping technologies allow the production of 3D structures with controlled architecture from models created by computer-aided design, through a layer-by-layer process. The present study describes the characterization of the chemical, mechanical and biological properties of βeta-Tricalcium phosphate/Alginate 3D scaffolds. The scaffolds were characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-Ray Diffraction and Water Contact Angle. Porosity and Mechanical properties (Compressive Strength and Young´s Modulus) were also analyzed. The cytotoxic profile was evaluated by in vitro MTS assays, using human osteoblastic cells. Confocal Laser Scanning Microscopy was also performed. The results obtained showed that the scaffolds produced by the Rapid Prototyping technique have good chemical and biological properties, which is fundamental for its application on bone tissue regeneration. Furthermore, it is concluded that the scaffolds showed better mechanical and biological properties with the increase of the percentage of βeta-Tricalcium phosphate within scaffolds.
- Bioactive polymeric–ceramic hybrid 3D scaffold for application in bone tissue regenerationPublication . Torres, Ana; Gaspar, V. M.; Serra, Inês Raquel Tavares; Carlos, Gabriela Soares Diogo; Fradique, Ricardo Gil; Silva, Abílio P.; Correia, I.J.The regeneration of large bone defects remains a challenging scenario from a therapeutic point of view. In fact, the currently available bone substitutes are often limited by poor tissue integration and severe host inflammatory responses, which eventually lead to surgical removal. In an attempt to address these issues, herein we evaluated the importance of alginate incorporation in the production of improved and tunable β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) three-dimensional (3D) porous scaffolds to be used as temporary templates for bone regeneration. Different bioceramic combinations were tested in order to investigate optimal scaffold architectures. Additionally, 3D β-TCP/HA vacuum-coated with alginate, presented improved compressive strength, fracture toughness and Young's modulus, to values similar to those of native bone. The hybrid 3D polymeric–bioceramic scaffolds also supported osteoblast adhesion, maturation and proliferation, as demonstrated by fluorescence microscopy. To the best of our knowledge this is the first time that a 3D scaffold produced with this combination of biomaterials is described. Altogether, our results emphasize that this hybrid scaffold presents promising characteristics for its future application in bone regeneration.
- Manufacture of β-TCP/alginate scaffolds through a Fab@home model for application in bone tissue engineeringPublication . Carlos, Gabriela Soares Diogo; Gaspar, Vítor Manuel Abreu; Serra, Inês Raquel Tavares; Fradique, Ricardo Gil; Correia, Ilídio Joaquim SobreiraThe growing need to treat bone-related diseases in an elderly population compels the development of novel bone substitutes to improve patient quality of life. In this context, the advent of affordable and effective rapid prototyping equipment, such as the Fab@home plotter, has contributed to the development of novel scaffolds for bone tissue engineering. In this study, we report for the first time the use of a Fab@home plotter for the production of 3D scaffolds composed by beta-tricalcium phosphate (β-TCP)/alginate hybrid materials. β-TCP/alginate mixtures were used in a proportion of 50/50% (w/w), 30/70% (w/w) and 20/80% (w/w). The printing parameters were optimized to a nozzle diameter of 20 Gauge for the production of rigid scaffolds with pre-defined architectures. We observed that, despite using similar printing parameters, both the precision and resolution of the scaffolds were significantly affected by the blend's viscosity. In particular, we demonstrate that the higher viscosity of 50/50 scaffolds (150.0 ± 3.91 mPa s) provides a higher precision in the extrusion process. The physicochemical and biological characterization of the samples demonstrated that the 50/50 scaffolds possessed a resistance to compression comparable to that of native trabecular bone. Moreover, this particular formulation also exhibited a Young's modulus that was higher than that of trabecular bone. Scanning electron microscopy and fluorescence microscopy analysis revealed that osteoblasts were able to adhere, proliferate and also penetrate into the scaffold's architecture. Altogether, our findings suggest that the Fab@home printer can be employed in the manufacture of reproducible scaffolds, using a formulation 50/50 alginate-β-TCP that has suitable properties to be applied as bone substitutes in the future.