Publicação
Chitosan-Silk scaffolds for piezoelectric regeneration of bone tissue
| Resumo: | Bone tissue can regenerate over the years, however, after a certain point, the rate of regeneration becomes lower than the rate of deterioration, resulting in loss of this tissue. This fact causes the tissue to become increasingly fragile, as well as certain diseases such as osteoarthritis, osteoporosis, which cannot be cured. However, the area of biomedical engineering has been developing scaffolds that can be implanted in the damaged location, enhancing the regeneration of bone tissue. In this work, scaffolds using biopolymers were developed, due to their biocompatibility and biodegradability. Piezoelectricity has demonstrated potential in this area, as it can enhance the growth and regeneration of bone tissue. However, despite the research about porous structures and their piezoelectricity, there is still a long way to go. Therefore, the main objective of this work was to create porous structures, consisting of two biopolymers with piezoelectric response and with mechanical and biological properties like those of bone tissue. The biopolymers chosen were chitosan (CS) and silk fibroin (SF), the latter is described in the literature as having a good electromechanical response. With this objective, porous structures of chitosan and silk were created with ratios 1:1 [CS/SF (1:1)] and 2:8 [CS/SF (2:8)], in terms of mass, using the ice templating process. In addition, structures with just one of the polymers were also prepared for better comparison. Through SEM analysis, it was found that CS had greater interconnectivity between pores than SF, resulting in greater interconnectivity in the mixture that had more CS. All samples, in general, had a heterogeneous structure, with pores of sizes between 100-300 μm, being higher for the sample containing only SF. The scaffolds presented high porosity, with values of 94.7%, 95.7%, 95.1% and 98.8% for CS, SF, CS/SF (1:1) and CS/SF (2:8), respectively. Through XRD analysis, it was noticed that polymers can interact with each other, presenting also the characteristic bands of the polymers that constitute them. FTIR allowed to confirm that combination of the two biopolymers created a peak at 1075 cm ˉ¹, which did not exist in samples with just one of the polymers, indicating their interaction. The cell viability of all samples was also tested, through MG-63 lineage, showing results above 70%, indicating that they are non-toxic to bone tissue. Furthermore, the swelling test showed values of 852%, 1196%, 837% and 1515% for CS, SF, CS/SF (1:1) and CS/SF (2 :8), respectively. When testing mechanical properties, SF and CS/SF (2:8) samples exhibited lower values, due to the random coils and α-helix chains being the most dominant silk structure, which confers a lower capacity to sustain loadings. The piezoelectric properties were tested and did not show adequate values to trigger the piezoelectric effect present in the bone for its regeneration. Through this research, it was realized that these materials interact well with each other, with high interconnectivity, are non-toxic to the organism and have high porosity, proving their potential for future studies. |
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| Autores principais: | Guedes, Joana Reis |
| Assunto: | Bone regeneration Scaffold Chitosan Silk Piezoelectricity Mechanical properties Biological properties |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso embargado |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Bone tissue can regenerate over the years, however, after a certain point, the rate of regeneration becomes lower than the rate of deterioration, resulting in loss of this tissue. This fact causes the tissue to become increasingly fragile, as well as certain diseases such as osteoarthritis, osteoporosis, which cannot be cured. However, the area of biomedical engineering has been developing scaffolds that can be implanted in the damaged location, enhancing the regeneration of bone tissue. In this work, scaffolds using biopolymers were developed, due to their biocompatibility and biodegradability. Piezoelectricity has demonstrated potential in this area, as it can enhance the growth and regeneration of bone tissue. However, despite the research about porous structures and their piezoelectricity, there is still a long way to go. Therefore, the main objective of this work was to create porous structures, consisting of two biopolymers with piezoelectric response and with mechanical and biological properties like those of bone tissue. The biopolymers chosen were chitosan (CS) and silk fibroin (SF), the latter is described in the literature as having a good electromechanical response. With this objective, porous structures of chitosan and silk were created with ratios 1:1 [CS/SF (1:1)] and 2:8 [CS/SF (2:8)], in terms of mass, using the ice templating process. In addition, structures with just one of the polymers were also prepared for better comparison. Through SEM analysis, it was found that CS had greater interconnectivity between pores than SF, resulting in greater interconnectivity in the mixture that had more CS. All samples, in general, had a heterogeneous structure, with pores of sizes between 100-300 μm, being higher for the sample containing only SF. The scaffolds presented high porosity, with values of 94.7%, 95.7%, 95.1% and 98.8% for CS, SF, CS/SF (1:1) and CS/SF (2:8), respectively. Through XRD analysis, it was noticed that polymers can interact with each other, presenting also the characteristic bands of the polymers that constitute them. FTIR allowed to confirm that combination of the two biopolymers created a peak at 1075 cm ˉ¹, which did not exist in samples with just one of the polymers, indicating their interaction. The cell viability of all samples was also tested, through MG-63 lineage, showing results above 70%, indicating that they are non-toxic to bone tissue. Furthermore, the swelling test showed values of 852%, 1196%, 837% and 1515% for CS, SF, CS/SF (1:1) and CS/SF (2 :8), respectively. When testing mechanical properties, SF and CS/SF (2:8) samples exhibited lower values, due to the random coils and α-helix chains being the most dominant silk structure, which confers a lower capacity to sustain loadings. The piezoelectric properties were tested and did not show adequate values to trigger the piezoelectric effect present in the bone for its regeneration. Through this research, it was realized that these materials interact well with each other, with high interconnectivity, are non-toxic to the organism and have high porosity, proving their potential for future studies. |
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