Publicação
A new approach for ligament regeneration based on graphene nanocomposites
| Resumo: | Ligament injuries are frequent and often require surgical reconstruction with auto-/ allografts, with severe limitations that have prompted a growing interest in the development of tissue-engineered scaffolds for ligament regeneration. Polylactic acid (PLA) is a biocompatible/biodegradable polymer with acceptable mechanical properties and routinely used for several medical applications. It may be reinforced with nanoparticles such as few-layer graphene to enhance the mechanical performance and provide other functionalities. Micronized graphite nanoplatelets (EG) may be covalently functionalized (f-EG) maintaining the excellent mechanical properties and providing adequate chemistry to bond with PLA, establishing strong interfaces that will enhance stress-transfer from polymer to reinforcement. Anchoring on f-EG a controlled concentration of silver nanoparticles ((f-EG)+Ag) may be beneficial for tissue regeneration by preventing bacterial adhesion and accelerating the healing process. The present work targeted the production of novel biodegradable and biocompatible graphenebased scaffolds, with controlled dimensions, as well as mechanical properties that match the requirements of the native human ligaments. Two alternative manufacturing techniques were investigated, one based on braiding, the other using 3D printing. To reach this goal, composite filaments of PLA reinforced with (f-EG)+Ag were produced by twin screw extrusion and melt-drawing, with enhanced mechanical performance for textile-engineered and 3D-printed ligament scaffolds. The composite filaments and scaffolds were extensively characterized by relevant techniques, being suitable for tendon/ligament tissue engineering applications. Scaffolds based on a medical grade PLA containing 0.5 wt.% of (f-EG)+Ag were produced by 3D printing. (f-EG)+Ag exhibited antibacterial properties against Staphylococcus aureus and Escherichia coli , an important feature for the healing process and prevention of bacterial infections. The scaffolds’ structure, biodegradation, and mechanical properties confirm their suitability for tendon and ligament regeneration. The PLA+[(f-EG)+Ag] scaffolds were nontoxic, and showed the ability to maintain the tenogenic commitment of human tendon-derived cells, with an increase in the gene expression of specific tendon/ligament-related markers. The results demonstrate the possibility for easy, cost-effective and personalized 3D-printed scaffolds with great potential applications for tendon and ligament regeneration. |
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| Autores principais: | Silva, Magda Sofia Gonçalves |
| Assunto: | 3D printing Graphite Ligaments PLA Grafite Impressão 3D Ligamentos |
| Ano: | 2024 |
| 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: | Ligament injuries are frequent and often require surgical reconstruction with auto-/ allografts, with severe limitations that have prompted a growing interest in the development of tissue-engineered scaffolds for ligament regeneration. Polylactic acid (PLA) is a biocompatible/biodegradable polymer with acceptable mechanical properties and routinely used for several medical applications. It may be reinforced with nanoparticles such as few-layer graphene to enhance the mechanical performance and provide other functionalities. Micronized graphite nanoplatelets (EG) may be covalently functionalized (f-EG) maintaining the excellent mechanical properties and providing adequate chemistry to bond with PLA, establishing strong interfaces that will enhance stress-transfer from polymer to reinforcement. Anchoring on f-EG a controlled concentration of silver nanoparticles ((f-EG)+Ag) may be beneficial for tissue regeneration by preventing bacterial adhesion and accelerating the healing process. The present work targeted the production of novel biodegradable and biocompatible graphenebased scaffolds, with controlled dimensions, as well as mechanical properties that match the requirements of the native human ligaments. Two alternative manufacturing techniques were investigated, one based on braiding, the other using 3D printing. To reach this goal, composite filaments of PLA reinforced with (f-EG)+Ag were produced by twin screw extrusion and melt-drawing, with enhanced mechanical performance for textile-engineered and 3D-printed ligament scaffolds. The composite filaments and scaffolds were extensively characterized by relevant techniques, being suitable for tendon/ligament tissue engineering applications. Scaffolds based on a medical grade PLA containing 0.5 wt.% of (f-EG)+Ag were produced by 3D printing. (f-EG)+Ag exhibited antibacterial properties against Staphylococcus aureus and Escherichia coli , an important feature for the healing process and prevention of bacterial infections. The scaffolds’ structure, biodegradation, and mechanical properties confirm their suitability for tendon and ligament regeneration. The PLA+[(f-EG)+Ag] scaffolds were nontoxic, and showed the ability to maintain the tenogenic commitment of human tendon-derived cells, with an increase in the gene expression of specific tendon/ligament-related markers. The results demonstrate the possibility for easy, cost-effective and personalized 3D-printed scaffolds with great potential applications for tendon and ligament regeneration. |
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