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Desenvolvimento, caracterização e otimização de um biocompósito cerâmico multifuncional
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| Documento em Acesso Embargado até dia 22-10-2027. Tente solicitar cópia ao autor carregando no ficheiro | 23.68 MB | Adobe PDF |
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Esta tese foca-se no desenvolvimento e otimização de biocerâmicas de Fosfato Tricálcico (TCP) dopado com iões metálicos e reforçado com grafeno ou zircónia, com o objetivo de criar materiais altamente biomiméticos para aplicações em engenharia de tecidos ósseos. O TCP foi dopado com iões de Mg2+, tendo obtido melhores propriedades mecânicas para TCP + 10 mol% Mg2+. Seguidamente, foi dopado com iões Mn2+, Zn2+ e Fe3+, cujas combinações foram otimizadas através do Design of Experiments (DoE) para combinação conjunta de 5 mol% total de dopagem, revelando que certas proporções promovem microestruturas densas, com boas propriedades mecânicas e ausência de citotoxicidade. Das várias composições testadas destacou-se o TCP dopado com 10 mol% Mg2+, 1,67 mol% Mn2+, 1,67 mol% Zn2+ e 1,67 mol% Fe3+ (TCP7). A adição de zircónia tetragonal e cúbica aumentou a resistência mecânica em até 55%, enquanto a porosidade interconectada, controlada com o porogénio Polimetilmetacrilato (PMMA), simulou a arquitetura óssea natural, favorecendo a viabilidade celular, mas reduziu a resistência mecânica em mais de 90%. Paralelamente, a incorporação de grafeno, até 3 wt%, melhorou significativamente a resistência à compressão diametral sem comprometer a biocompatibilidade, demonstrada em ensaios de citotoxicidade. A composição com melhores propriedades mecânicas foi o TCP7 com 1,5 wt% de grafeno. Para apoiar o design racional destes materiais, foi desenvolvida uma abordagem de modelação numérica avançada baseada em microestruturas reais 2D, permitindo gerar Volume Elementar Representativo (RVE) em 3D que preveem com alta precisão o módulo de Young dos compósitos, superando métodos analíticos convencionais. Em conjunto, os resultados demonstraram que é possível conceber biocerâmicas de TCP com propriedades mecânicas reforçadas, arquitetura porosa controlada e elevada citocompatibilidade, graças a uma estratégia multifatorial que combina dopagem iónica, reforço com nanomateriais e simulação digital. Estes avanços posicionaram os materiais desenvolvidos como candidatos promissores para implantes ósseos multifuncionais, com forte potencial clínico em ortopedia e odontologia.
This thesis focuses on the development and optimisation of bioceramics made of Tricalcium Phosphate (TCP) doped with metal ions and reinforced with graphene or zirconia, with the aim of creating highly biomimetic materials for applications in bone tissue engineering. The TCP was doped with Mg2+ ions, obtaining better mechanical properties for TCP + 10 mol% Mg2+. Subsequently, it was doped with Mn2+, Zn2+, and Fe3+ ions, whose combinations were optimised through Design of Experiments (DoE) for a joint combination of 5 mol% total doping, revealing that certain proportions promote dense microstructures with good mechanical properties and no cytotoxicity. Of the various compositions tested, TCP doped with 10 mol% Mg2+, 1,67 mol% Mn2+, 1,67 mol% Zn2+ and 1,67 mol% Fe3+ (TCP7) stood out. The addition of tetragonal and cubic zirconia increased mechanical strength by up to 55%, while interconnected porosity — controlled with the porogen Polymethylmethacrylate (PMMA) — simulated natural bone architecture, favouring cell viability, but reduced mechanical strength by more than 90%. At the same time, the incorporation of graphene, up to 3 wt%, significantly improved diametral compressive strength without compromising biocompatibility, as demonstrated in cytotoxicity tests. The composition with the best mechanical properties was TCP7 with 1.5 wt% graphene. To support the rational design of these materials, an advanced numerical modelling approach based on real 2D microstructures was developed, allowing the generation of 3D RVE that predict the Young’s modulus of the composites with high accuracy, surpassing conventional analytical methods. Together, the results demonstrated that it is possible to design TCP bioceramics with enhanced mechanical properties, controlled porous architecture, and high cytocompatibility, thanks to a multifactorial strategy combining ion doping, reinforcement with nanomaterials, and digital simulation. These advances have positioned the developed materials as promising candidates for multifunctional bone implants, with strong clinical potential in orthopaedics and dentistry.
This thesis focuses on the development and optimisation of bioceramics made of Tricalcium Phosphate (TCP) doped with metal ions and reinforced with graphene or zirconia, with the aim of creating highly biomimetic materials for applications in bone tissue engineering. The TCP was doped with Mg2+ ions, obtaining better mechanical properties for TCP + 10 mol% Mg2+. Subsequently, it was doped with Mn2+, Zn2+, and Fe3+ ions, whose combinations were optimised through Design of Experiments (DoE) for a joint combination of 5 mol% total doping, revealing that certain proportions promote dense microstructures with good mechanical properties and no cytotoxicity. Of the various compositions tested, TCP doped with 10 mol% Mg2+, 1,67 mol% Mn2+, 1,67 mol% Zn2+ and 1,67 mol% Fe3+ (TCP7) stood out. The addition of tetragonal and cubic zirconia increased mechanical strength by up to 55%, while interconnected porosity — controlled with the porogen Polymethylmethacrylate (PMMA) — simulated natural bone architecture, favouring cell viability, but reduced mechanical strength by more than 90%. At the same time, the incorporation of graphene, up to 3 wt%, significantly improved diametral compressive strength without compromising biocompatibility, as demonstrated in cytotoxicity tests. The composition with the best mechanical properties was TCP7 with 1.5 wt% graphene. To support the rational design of these materials, an advanced numerical modelling approach based on real 2D microstructures was developed, allowing the generation of 3D RVE that predict the Young’s modulus of the composites with high accuracy, surpassing conventional analytical methods. Together, the results demonstrated that it is possible to design TCP bioceramics with enhanced mechanical properties, controlled porous architecture, and high cytocompatibility, thanks to a multifactorial strategy combining ion doping, reinforcement with nanomaterials, and digital simulation. These advances have positioned the developed materials as promising candidates for multifunctional bone implants, with strong clinical potential in orthopaedics and dentistry.
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TCP dopado com iões metálicos DoE Análise Mecânica Análise Biológica Iões metálicos Citotoxicidade RVE Simulação Numérica Módulo de Young Grafeno TCP doped with metal ions Mechanical Analysis Biological Analysis Metal Ions Citotoxicity Numerical Simulation Young’s Modulus Graphene