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Development by robocasting of scaffolds of HAp-ZnO and HAp-MgO composites for bone tissue regeneration
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Advisor(s)
Abstract(s)
As doenças e traumas ósseos afetam milhões de pessoas a nível global e, com o aumento da
esperança média de vida, prevê-se que a sua prevalência continue a crescer. Os implantes
metálicos representam o golden standard nos tratamentos atuais. No entanto, em casos mais
graves, torna-se necessário recorrer a substitutos ósseos, como enxertos. Este tipo de
abordagem enfrenta diversas limitações, incluindo disponibilidade reduzida, dimensões
inadequadas e risco de rejeição imunológica. Neste contexto, a impressão 3D surge como
uma solução inovadora, possibilitando a criação de enxertos sintéticos personalizados para
cada paciente, utilizando materiais biocompatíveis que promovem a regeneração óssea,
reduzindo complicações e acelerando a recuperação.
O objetivo deste estudo consiste no desenvolvimento de scaffolds compósitos à base de
hidroxiapatite, incorporando óxido de zinco e óxido de magnésio, para o tratamento do tecido
ósseo. Estes scaffolds foram produzidos através da técnica de impressão 3D Robocasting,
com o intuito de estudar como esta tecnologia pode melhorar a produção de enxertos
sintéticos, tornando-os mais compatíveis com cada paciente, explorando as suas limitações
ao produzir diferentes geometrias.
Para a produção dos scaffolds, foi possível desenvolver pastas com uma reologia adequada
para impressão 3D, alcançando 58wt% de sólidos. Através da formulação base, foram
produzidas 4 geometrias diferentes, com propriedades mecânicas similares ao osso
trabecular. Sendo a geometria Honeycomb que mais se destacou, por ser uma geometria
complexa e por ter boas propriedades mecânicas. Com a incorporação de óxido de zinco e
óxido de magnésio na formulação, as pastas de HAp-ZnO registaram uma diminuição de
viscosidade. Através dos estudos realizados, os scaffolds HAp-ZnO obtiveram uma
diminuição de porosidade e consequentemente um aumento das propriedades mecânicas
superando resistência à compressão do osso trabecular. O grupo HAp-MgO registou um
aumento de porosidade, que afetou diretamente as suas propriedades mecânicas. Contudo,
quando submetidas a ensaios in vitro, as amostras de HAp-MgO apresentaram maior variação
de peso e alterações na superfície em comparação com os restantes grupos.
Os resultados demonstram as capacidades de produzir scaffolds com diferentes geometrias
e integrar diferentes biomateriais através da tecnologia Robocasting. Além disso, evidenciam
como estas modificações impactam as propriedades microestruturais e mecânicas do
scaffolds. Apontando um caminho promissor para a impressão 3D no desenvolvimento de
enxertos personalizados para substituição óssea.
Bone problems and trauma affect millions of people worldwide and, with the increase in life expectancy, their prevalence is expected to continue rising. Metallic implants represent the gold standard in current treatments. However, in more severe cases, it becomes necessary to resort to bone substitutes, such as grafts. This approach faces several limitations, including limited availability, inadequate dimensions, and the risk of immune rejection. In this context, 3D printing emerges as an innovative solution, enabling the creation of synthetic grafts tailored to each patient, using biocompatible materials that promote bone regeneration, reduce complications, and accelerate recovery. The aim of this study is to develop composite scaffolds based on hydroxyapatite, incorporating zinc oxide and magnesium oxide, for bone tissue treatment. These scaffolds were produced by Robocasting, with the objective to understand how this technology can improve the production of synthetic grafts, making them more compatible with individual patients and addressing their limitations by producing different geometries. For scaffold production, it was possible to develop pastes with rheology properties suitable for 3D printing, achieving 58wt% solids. Using the base formulation, four different geometries were produced, with mechanical properties similar to trabecular bone. Among these, the Honeycomb geometry stood out for its structural complexity and excellent mechanical properties. With the incorporation of zinc oxide and magnesium oxide into the formulation, HAp-ZnO pastes showed a decrease in viscosity. Through the conducted studies, HAp-ZnO scaffolds exhibited reduced porosity and, consequently, improved mechanical properties, surpassing the compressive strength of trabecular bone. The HAp-MgO group exhibited an increase in porosity, which directly affected its mechanical properties. However, when subjected to in vitro tests, the HAp-MgO samples showed greater weight variation and surface alterations compared to the other groups. The results demonstrate the ability to produce scaffolds with different geometries and integrate various biomaterials through Robocasting technology. Moreover, they highlight how these modifications impact the microstructural and mechanical properties of the scaffolds, indicating a promising pathway for 3D printing in the development of personalized scaffolds for bone treatment.
Bone problems and trauma affect millions of people worldwide and, with the increase in life expectancy, their prevalence is expected to continue rising. Metallic implants represent the gold standard in current treatments. However, in more severe cases, it becomes necessary to resort to bone substitutes, such as grafts. This approach faces several limitations, including limited availability, inadequate dimensions, and the risk of immune rejection. In this context, 3D printing emerges as an innovative solution, enabling the creation of synthetic grafts tailored to each patient, using biocompatible materials that promote bone regeneration, reduce complications, and accelerate recovery. The aim of this study is to develop composite scaffolds based on hydroxyapatite, incorporating zinc oxide and magnesium oxide, for bone tissue treatment. These scaffolds were produced by Robocasting, with the objective to understand how this technology can improve the production of synthetic grafts, making them more compatible with individual patients and addressing their limitations by producing different geometries. For scaffold production, it was possible to develop pastes with rheology properties suitable for 3D printing, achieving 58wt% solids. Using the base formulation, four different geometries were produced, with mechanical properties similar to trabecular bone. Among these, the Honeycomb geometry stood out for its structural complexity and excellent mechanical properties. With the incorporation of zinc oxide and magnesium oxide into the formulation, HAp-ZnO pastes showed a decrease in viscosity. Through the conducted studies, HAp-ZnO scaffolds exhibited reduced porosity and, consequently, improved mechanical properties, surpassing the compressive strength of trabecular bone. The HAp-MgO group exhibited an increase in porosity, which directly affected its mechanical properties. However, when subjected to in vitro tests, the HAp-MgO samples showed greater weight variation and surface alterations compared to the other groups. The results demonstrate the ability to produce scaffolds with different geometries and integrate various biomaterials through Robocasting technology. Moreover, they highlight how these modifications impact the microstructural and mechanical properties of the scaffolds, indicating a promising pathway for 3D printing in the development of personalized scaffolds for bone treatment.
Description
Keywords
Tecido ósseo Impressão 3D Forma dos poros Hidroxiapatite Óxido de Zinco Óxido de Magnésio Bone tissue 3D Printing Pore shape Hydroxyapatite Zinc Oxide Magnesium Oxide