Development of multifunctional hybrid scaffolds for massive bone defects filling and regeneration

• Autor(a) principal: Amaral, Miguel Filipe Lourenço de
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/130561
• topic: 3D printing; Chitosan; Drug delivery; Hydrogel; Scaffold; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

Despite the growing number of survival cases, due to the increase in cases, the death rate from cancer-related diseases has been increasing over the years. Being less than 0.2% of all cancers, primary bone cancers are extremely unusual and often curable. However, about 50% of these tumors can metastasize, so early intervention is frequently necessary. Tumor or tumor-like resection derived from osteosarcoma usually leads to the creation of large bone defects, which constitute a reconstructive problem. The current standard procedures used to resolve this and other related issues are viable solutions. However, they are far from being ideal, still carrying many risks, and often failing. With the ongoing advances in a variety of theoretical subjects and in manufacturing (namely 3D printing), bone graft substitutes using smart biodegradable scaffolds are revolutionizing bone tissue engineering and regenerative medicine. In addition, despite the numerous options currently available, the scientific consensus is that the ideal bone graft should likely have a hybrid composition. The goal of this thesis is to provide an overall review of the current state-of-the-art on the main concepts associated with chitosan-based 3D scaffolds. Porous scaffolds produced by conventional fabrication techniques, using chemically cross-linked chitosan hydrogel are analysed. Due to its growing popularity, cross-linking agent genipin was selected as a case study. Follows an analysis on the most recent methods of scaffold fabrication reinforced by rapid prototyping techniques (PLA is further examined as printing material). The incorporation of bioactive agents and cells is evaluated in both options. The different factors that influence the properties of each material, the overall performance of the 3D structures, and the most common methods of surface modification are also discussed topics. To finalize, the key aspects that still need improvement and future perspectives for scaffold technology are highlighted.