Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10773/36012 |
Resumo: | Melt-electrowriting (MEW) is an emerging technology that has been developed to produce scaffolds with three-dimensional ordered, precise and porous structures with fibre size smaller than 100 μm. Calcium phosphates facilitate bone growth and improve scaffolds bioactivity, which is essential for bone tissue engineering. Incorporating calcium phosphate particles, such as hydroxyapatite (HAp), into fibrous scaffolds is therefore desirable. However, this remains a challenge in MEW as HAp particles can agglomerate and hinder a continuous printing process. The polymer poly(ε-caprolactone) (PCL) and the copolymer of ε-caprolactone/ lactic acid (PCL/PLA) were selected as materials in this work. In the first part of the work, PCL and PCL/PLA were characterised, and it was observed that the copolymer exhibits slight thermal degradation when heated. Moreover, the copolymer showed a lower Young modulus than PCL. Melt-electrowritten scaffolds were produced with both polymers. PCL scaffolds showed aligned fibres, while PCL/PLA scaffolds had misaligned fibres and decreased porosity compared to PCL scaffolds. In the second part of this work, blends of the two polymers with two types of HAp powders – a nanoHAp and a microHAp – were produced. After characterization, the blends demonstrated a HAp particles’ loading near the planned amount (3.5 wt%), and the addition of HAp particles enhanced the Young modulus compared to the plain polymer. The printing parameters for MEW were optimised with the produced blends, and composite melt-electrowritten scaffolds were printed. PCL composite scaffolds with a pore size of 500 μm demonstrated aligned fibres with defined porosity. PCL/PLA-microHAp composite melt-electrowritten scaffolds never described in the literature before were produced in this work. The scaffolds did not present aligned fibres, nevertheless, this study represents an important advance in the optimization of the printing process. PCL/PLA-nanoHAp scaffolds were not possible to print due to particle agglomeration. The tendency of nano-HAp to agglomerate disrupted the printing process, whereas the micro-HAp agglomerated less and proved superior performance for scaffold production by MEW. The scaffolds were seeded with human mesenchymal stem cells and allowed their attachment and proliferation, showing potential for bone tissue engineering. |
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Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regenerationMelt-electrowritingBone tissue engineering3D scaffoldComposite materialsMelt-electrowriting (MEW) is an emerging technology that has been developed to produce scaffolds with three-dimensional ordered, precise and porous structures with fibre size smaller than 100 μm. Calcium phosphates facilitate bone growth and improve scaffolds bioactivity, which is essential for bone tissue engineering. Incorporating calcium phosphate particles, such as hydroxyapatite (HAp), into fibrous scaffolds is therefore desirable. However, this remains a challenge in MEW as HAp particles can agglomerate and hinder a continuous printing process. The polymer poly(ε-caprolactone) (PCL) and the copolymer of ε-caprolactone/ lactic acid (PCL/PLA) were selected as materials in this work. In the first part of the work, PCL and PCL/PLA were characterised, and it was observed that the copolymer exhibits slight thermal degradation when heated. Moreover, the copolymer showed a lower Young modulus than PCL. Melt-electrowritten scaffolds were produced with both polymers. PCL scaffolds showed aligned fibres, while PCL/PLA scaffolds had misaligned fibres and decreased porosity compared to PCL scaffolds. In the second part of this work, blends of the two polymers with two types of HAp powders – a nanoHAp and a microHAp – were produced. After characterization, the blends demonstrated a HAp particles’ loading near the planned amount (3.5 wt%), and the addition of HAp particles enhanced the Young modulus compared to the plain polymer. The printing parameters for MEW were optimised with the produced blends, and composite melt-electrowritten scaffolds were printed. PCL composite scaffolds with a pore size of 500 μm demonstrated aligned fibres with defined porosity. PCL/PLA-microHAp composite melt-electrowritten scaffolds never described in the literature before were produced in this work. The scaffolds did not present aligned fibres, nevertheless, this study represents an important advance in the optimization of the printing process. PCL/PLA-nanoHAp scaffolds were not possible to print due to particle agglomeration. The tendency of nano-HAp to agglomerate disrupted the printing process, whereas the micro-HAp agglomerated less and proved superior performance for scaffold production by MEW. The scaffolds were seeded with human mesenchymal stem cells and allowed their attachment and proliferation, showing potential for bone tissue engineering.Melt-electrowriting (MEW) é uma tecnologia emergente que foi desenvolvida para produzir scaffolds com estruturas tridimensionais ordenadas, precisas e porosas, possibilitando obter tamanhos de fibras menores que 100 μm. Fosfatos de cálcio facilitam o crescimento ósseo e melhoram a bioatividade dos scaffolds, que é essencial para a engenharia de tecido ósseo. A incorporação de partículas de fosfatos de cálcio, como hidroxiapatite (HAp), em scaffolds fibrosas é, portanto, desejável. No entanto, continua a ser um obstáculo em MEW, dado que as partículas de HAp podem aglomerar e dificultar um processo de impressão contínuo. O polímero poly(ε-caprolactone) (PCL) e o copolímero of ε-caprolactone/ lactic acid (PCL/PLA) foram selecionados como materiais poliméricos neste trabalho. Na primeira parte do trabalho, os dois polímeros, PCL e PCL/PLA foram caracterizados e observou-se que o copolímero apresentou alguma degradação térmica quando aquecido durante algumas horas. Além disso, o copolímero apresentou um módulo de Young menor que o PCL. Scaffolds destes dois polímeros foram produzidos por MEW. Os scaffolds de PCL/PLA apresentaram fibras desalinhadas e diminuição da porosidade quando comparados aos scaffolds PCL, que por sua vez apresentaram fibras alinhadas e porosidade definida. Na segunda parte do trabalho, foram produzidas misturas dos dois polímeros com dois tipos de pós de HAp – um pó com partículas nanométricas (nanoHAp) e um com partículas micrométricas (microHAp). As misturas foram caracterizadas, e demonstraram a incorporação de uma quantidade de partículas perto de 3.5 % em massa, que foi a quantidade desejada. Além disso, a adição de partículas de HAp aumentou o módulo de Young em comparação com o polímero. Os parâmetros de impressão foram otimizados com as misturas produzidas, e scaffolds compósitos foram produzidos por MEW. Os scaffolds compósitos de PCL-microHAp e PCL-nanoHAp com um tamanho de poro de 500 μm apresentaram fibras alinhadas com porosidade definida. Neste trabalho, foram produzidos scaffolds compósitos por MEW de PCL/PLA-microHAp nunca descritos na literatura. Os scaffolds não apresentaram fibras alinhadas, no entanto, este estudo representa um avanço importante na otimização do processo de impressão. Scaffolds de PCL/PLA-nanoHAp não foram possíveis imprimir devido à aglomeração de partículas. A tendência de aglomeração da nano-HAp prejudicou o processo de impressão, enquanto que a micro-HAp demonstrou menos aglomeração e teve um desempenho superior para produção de scaffolds por MEW. Os scaffolds foram semeados com células-tronco mesenquimais humanas e permitiram a sua fixação e proliferação, mostrando potencial para regeneração de tecido ósseo.2022-102022-10-01T00:00:00Z2024-10-31T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10773/36012engFerreira, Marta Albuquerque Cristóvãoinfo:eu-repo/semantics/embargoedAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-02-22T12:09:35Zoai:ria.ua.pt:10773/36012Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:07:00.214963Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
title |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
spellingShingle |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration Ferreira, Marta Albuquerque Cristóvão Melt-electrowriting Bone tissue engineering 3D scaffold Composite materials |
title_short |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
title_full |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
title_fullStr |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
title_full_unstemmed |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
title_sort |
Melt-electrowritten scaffolds containing hydroxyapatite for guided bone tissue regeneration |
author |
Ferreira, Marta Albuquerque Cristóvão |
author_facet |
Ferreira, Marta Albuquerque Cristóvão |
author_role |
author |
dc.contributor.author.fl_str_mv |
Ferreira, Marta Albuquerque Cristóvão |
dc.subject.por.fl_str_mv |
Melt-electrowriting Bone tissue engineering 3D scaffold Composite materials |
topic |
Melt-electrowriting Bone tissue engineering 3D scaffold Composite materials |
description |
Melt-electrowriting (MEW) is an emerging technology that has been developed to produce scaffolds with three-dimensional ordered, precise and porous structures with fibre size smaller than 100 μm. Calcium phosphates facilitate bone growth and improve scaffolds bioactivity, which is essential for bone tissue engineering. Incorporating calcium phosphate particles, such as hydroxyapatite (HAp), into fibrous scaffolds is therefore desirable. However, this remains a challenge in MEW as HAp particles can agglomerate and hinder a continuous printing process. The polymer poly(ε-caprolactone) (PCL) and the copolymer of ε-caprolactone/ lactic acid (PCL/PLA) were selected as materials in this work. In the first part of the work, PCL and PCL/PLA were characterised, and it was observed that the copolymer exhibits slight thermal degradation when heated. Moreover, the copolymer showed a lower Young modulus than PCL. Melt-electrowritten scaffolds were produced with both polymers. PCL scaffolds showed aligned fibres, while PCL/PLA scaffolds had misaligned fibres and decreased porosity compared to PCL scaffolds. In the second part of this work, blends of the two polymers with two types of HAp powders – a nanoHAp and a microHAp – were produced. After characterization, the blends demonstrated a HAp particles’ loading near the planned amount (3.5 wt%), and the addition of HAp particles enhanced the Young modulus compared to the plain polymer. The printing parameters for MEW were optimised with the produced blends, and composite melt-electrowritten scaffolds were printed. PCL composite scaffolds with a pore size of 500 μm demonstrated aligned fibres with defined porosity. PCL/PLA-microHAp composite melt-electrowritten scaffolds never described in the literature before were produced in this work. The scaffolds did not present aligned fibres, nevertheless, this study represents an important advance in the optimization of the printing process. PCL/PLA-nanoHAp scaffolds were not possible to print due to particle agglomeration. The tendency of nano-HAp to agglomerate disrupted the printing process, whereas the micro-HAp agglomerated less and proved superior performance for scaffold production by MEW. The scaffolds were seeded with human mesenchymal stem cells and allowed their attachment and proliferation, showing potential for bone tissue engineering. |
publishDate |
2022 |
dc.date.none.fl_str_mv |
2022-10 2022-10-01T00:00:00Z 2024-10-31T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/masterThesis |
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masterThesis |
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publishedVersion |
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http://hdl.handle.net/10773/36012 |
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http://hdl.handle.net/10773/36012 |
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eng |
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eng |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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