Publicação
Gellan gum-based hydrogels for tissue engineering applications
| Resumo: | The use of hydrogels as platforms for Tissue Engineering and Regenerative Medicine approaches has been growing in the past years. Their resemblance to the natural extracellular matrix, and facility to modify and tailor their final properties are some of the aspects that appeal researchers around the world to use this type of material. Different hydrogel sources have been exploited and processed using different methodologies, resulting in different structures that can be tailored for the intended application. Indeed, cell-material interactions can be adjusted by using distinct hydrogel designs, processing methods or sources. One of the natural materials that has been considered for Tissue Engineering and Regenerative Medicine strategies is gellan gum. This natural polymer has been used for different applications over the last years, on its natural form or after chemical modifications. Among such modifications, gellan gum methacrylation already showed promising results on Tissue Engineering. Nevertheless, the impact of the crosslinking and processing strategies used with the material are still not well established. This thesis aimed to highlight the versatility of this polymer, achieved by using different crosslinking strategies. Ionic crosslinking with calcium chloride, one of the most used methods to prepare gellan gum hydrogels, were firstly considered envisioning bone tissue engineering. Ionic crosslinking was also used to prepare traceable hydrogels, taking advantage of the affinity of methacrylated gellan gum to the divalent paramagnetic manganese ion. The ionic-responsive property of gellan gum allowed a minimally invasive administration of gellan gum in the vicinities of the central nervous system, as well as the desired traceability. At last, a different strategy was used to obtain hydrogels with immunoprotective capabilities, intended to be used on immunoisolation strategies. Polyelectrolyte complexation of gellan gum with poly l-lysine yielded a semipermeable membrane, capable of blocking the passage of the immune cells towards the hydrogel core, where therapeutic cells are encapsulated. Altogether, the different approaches used on the scope of this thesis showed the versatility of methacrylated gellan gum and the importance of carefully chose the crosslinked methodology to prepare hydrogels, as they greatly influence final hydrogel behaviour. |
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| Autores principais: | Vieira, Sílvia Cristina Araújo |
| Assunto: | Crosslinking Hydrogels Methacrylated gellan gum Tissue engineering and regenerative medicine Goma gelana metacrilada Hidrogéis Reticulação Engenharia de tecidos e medicina regenerativa |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The use of hydrogels as platforms for Tissue Engineering and Regenerative Medicine approaches has been growing in the past years. Their resemblance to the natural extracellular matrix, and facility to modify and tailor their final properties are some of the aspects that appeal researchers around the world to use this type of material. Different hydrogel sources have been exploited and processed using different methodologies, resulting in different structures that can be tailored for the intended application. Indeed, cell-material interactions can be adjusted by using distinct hydrogel designs, processing methods or sources. One of the natural materials that has been considered for Tissue Engineering and Regenerative Medicine strategies is gellan gum. This natural polymer has been used for different applications over the last years, on its natural form or after chemical modifications. Among such modifications, gellan gum methacrylation already showed promising results on Tissue Engineering. Nevertheless, the impact of the crosslinking and processing strategies used with the material are still not well established. This thesis aimed to highlight the versatility of this polymer, achieved by using different crosslinking strategies. Ionic crosslinking with calcium chloride, one of the most used methods to prepare gellan gum hydrogels, were firstly considered envisioning bone tissue engineering. Ionic crosslinking was also used to prepare traceable hydrogels, taking advantage of the affinity of methacrylated gellan gum to the divalent paramagnetic manganese ion. The ionic-responsive property of gellan gum allowed a minimally invasive administration of gellan gum in the vicinities of the central nervous system, as well as the desired traceability. At last, a different strategy was used to obtain hydrogels with immunoprotective capabilities, intended to be used on immunoisolation strategies. Polyelectrolyte complexation of gellan gum with poly l-lysine yielded a semipermeable membrane, capable of blocking the passage of the immune cells towards the hydrogel core, where therapeutic cells are encapsulated. Altogether, the different approaches used on the scope of this thesis showed the versatility of methacrylated gellan gum and the importance of carefully chose the crosslinked methodology to prepare hydrogels, as they greatly influence final hydrogel behaviour. |
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