Publicação
One-step all-aqueous fabrication of tubular pre-endothelized structures
| Resumo: | Blood vessels are one of the most important constituents of the human body. They are responsible for maintaining tissue function and survival by providing oxygen and nutrients, as well as to provide essential molecules and biochemical signaling during tissue development and regeneration, which depend on the formation of new vascular structures. The ability to develop in vitro hollow and tubular structures capable of supporting cell functionality and mimicking biological architectures of native tissues such as blood vessels have the potential to foster scientific and technological advances in the fields of tissue engineering and regenerative medicine. Classical methods to fabricate self-sustained tubular structures are normally dependent on pre- and post-processing steps, or complex and non straightforward techniques, often incompatible with the fabrication of free-form architectures. The generation of tubular fiber-shaped materials through methods that allow their direct fabrication and their deposition in versatile shapes and directions in a spatial- and size-controlled manner may be key to overcome some of those limitations. Aqueous two-phase systems (ATPS), which behave as fully aqueous emulsions, have started to be recently explored in the biomedical field. Those are mostly used as templates for the generation of sophisticated biomaterials. Interfacial complexation of oppositely charged polyelectrolytes has been exploited as a valuable strategy for the production of materials using template ATPS. Most studies in the literature have focused at the fabrication of spherical shaped materials for the encapsulation of bioactive and delicate cargos. However, the production of fiber materials with a tubular structure by this strategy has been poorly explored, and its ability to allow cell encapsulation, viability and long-term culture has not been yet reported. In this project, we purpose a rapid strategy to fabricate hollow fiber-shaped materials in a full aqueous environment stabilized by an interfacial membrane resultant from the complexation of two naturally-derived oppositely charged polyelectrolytes. Simple straight or branched structures amenable to be perfused with liquids could be produced, and tubular features of the structures could be confirmed by scanning electron microscopy. The stability of the fabricated material was dependent on polyelectrolytes’ concentration, complexation time, and on the system’s pH. In addition, the mechanical properties and swelling behavior of the fibers could be tuned by complexation time, and their diameter could be tailored from millimeters to the micrometer scale. Encapsulation of human stem cells derived from adipose tissue (hASCs) demonstrated the ability of the system to withstand cell viability and adhesion up to 7 days, in systems containing cell adhesion sequences. Heterotypic fibers containing hASCs in co-culture with human umbilical vein endothelial cells (HUVECs) enabled endothelial cell survival for at least 14 days, which was confirmed by immunocytochemistry. This work may represent relevant advances on the easy and one-step fabrication of biomaterial-based structures with the ability to resemble native tubular tissues with biological relevance. |
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| Autores principais: | Gonçalves, Raquel Maria da Costa |
| Assunto: | Blood vessels Tissue engineering Aqueous two-phase systems Interfacial complexation Cell encapsulation Cytocompatibility Endothelial cells |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Aveiro |
| Idioma: | inglês |
| Origem: | RIA - Repositório Institucional da Universidade de Aveiro |
| Resumo: | Blood vessels are one of the most important constituents of the human body. They are responsible for maintaining tissue function and survival by providing oxygen and nutrients, as well as to provide essential molecules and biochemical signaling during tissue development and regeneration, which depend on the formation of new vascular structures. The ability to develop in vitro hollow and tubular structures capable of supporting cell functionality and mimicking biological architectures of native tissues such as blood vessels have the potential to foster scientific and technological advances in the fields of tissue engineering and regenerative medicine. Classical methods to fabricate self-sustained tubular structures are normally dependent on pre- and post-processing steps, or complex and non straightforward techniques, often incompatible with the fabrication of free-form architectures. The generation of tubular fiber-shaped materials through methods that allow their direct fabrication and their deposition in versatile shapes and directions in a spatial- and size-controlled manner may be key to overcome some of those limitations. Aqueous two-phase systems (ATPS), which behave as fully aqueous emulsions, have started to be recently explored in the biomedical field. Those are mostly used as templates for the generation of sophisticated biomaterials. Interfacial complexation of oppositely charged polyelectrolytes has been exploited as a valuable strategy for the production of materials using template ATPS. Most studies in the literature have focused at the fabrication of spherical shaped materials for the encapsulation of bioactive and delicate cargos. However, the production of fiber materials with a tubular structure by this strategy has been poorly explored, and its ability to allow cell encapsulation, viability and long-term culture has not been yet reported. In this project, we purpose a rapid strategy to fabricate hollow fiber-shaped materials in a full aqueous environment stabilized by an interfacial membrane resultant from the complexation of two naturally-derived oppositely charged polyelectrolytes. Simple straight or branched structures amenable to be perfused with liquids could be produced, and tubular features of the structures could be confirmed by scanning electron microscopy. The stability of the fabricated material was dependent on polyelectrolytes’ concentration, complexation time, and on the system’s pH. In addition, the mechanical properties and swelling behavior of the fibers could be tuned by complexation time, and their diameter could be tailored from millimeters to the micrometer scale. Encapsulation of human stem cells derived from adipose tissue (hASCs) demonstrated the ability of the system to withstand cell viability and adhesion up to 7 days, in systems containing cell adhesion sequences. Heterotypic fibers containing hASCs in co-culture with human umbilical vein endothelial cells (HUVECs) enabled endothelial cell survival for at least 14 days, which was confirmed by immunocytochemistry. This work may represent relevant advances on the easy and one-step fabrication of biomaterial-based structures with the ability to resemble native tubular tissues with biological relevance. |
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