Magnesium-based Biodegradable Scaffolds for Bone Tissue Regeneration

• Autor(a) principal: Oliveira, Beatriz Catarino
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/163643
• topic: Bone Regeneration; Additive Manufactured Scaffolds; Hydrogel; Magnesium; Tissue Engineering; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Bone, a remarkable tissue with the ability to naturally regenerate when slightly damaged, faces limitations when submitted to critical injuries that can inhibit its inherent healing process, necessitating external interventions like bone grafts, which present challenges, restricting their clinical application. Thus, biodegradable materials have gained importance to be used for bone replacement alternatives. These materials can be manipulated to obtain porous structures in several forms, promoting cell proliferation and adhesion while supporting the formation of new bone. Magnesium (Mg) emerges as an attractive biomaterial for these scenarios due to its biodegradability, mechanical properties similar to natural bone, and its predominant presence in bones, making it an ideal candidate for bone applications. The primary goal of this studywas to manufacture temporary implants for bone regeneration. Three approaches were studied incorporating Mg to achieve this: i) three-dimensional (3D) Additive Manufactured (AM) scaffolds; ii) hydrogels; and iii) hybrid, through the combination of a scaffold with hydrogel. To produce theAMscaffolds, two weight percentages of Mg, 5 and 15%, were used in two forms, Magnesium Oxide, MgO, and Magnesium Sulphate, MgSO4. The addition of Mg resulted in a rough surface and enhanced mechanical properties, with an optimal Mg content of 5%, presenting the highest resistance to compression. A synthetic polymer, PEGDA, was used as the hydrogel base, and MgSO4 was added. The mechanical properties of the Mg group showed an improvement in the compressive Young’s Modulus (2.28 MPa) and an increase in their ductility. The plateau reached after an intital weight increase proved that these hydrogels do not degrade immediately, being stable enough to help bone regeneration. A third approach was made, combining the two previously mentioned, an AM scaffold with a Mg-hydrogel. Notably, the mechanical properties of this strategy surpassed those of both previous approaches. The results demonstrated that the hybrid approach presents a mechanical behaviour closer to the levels found in natural bone, reaching Compressive Young’s Modulus of about 2 GPa.