Production and characterization of magnetic bioactive glass membranes

• Autor(a) principal: Rodrigues, José Miguel Botica
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10362/80557
• topic: Bioactive glass; bone regeneration; composite membranes; iron oxide nano-particles; magnetic hyperthermia; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Bone cancer treatment usually originates bone defects with residual tumour cells that can proliferate during bone regeneration. Therefore, a scaffold for bone regeneration that simultaneously kill residual tumour cells is needed. This project aims at producing a composite system composed of a bioactive glass (BAG) and magnetic nanoparticles (MNPs). This system is highly bioactive and reabsorbable due to the bioactive glass which leads to formation of a hydroxyapatite (HA) layer that bonds to bone. The system is biodegradable at an adequate rate for bone regeneration. Magnetic nanoparticles act as thermoseeds generating clinically relevant heat under an applied alternating magnetic field to kill or sensitize tumour cells. In combination with release of an anticancer drug, this composite system will effectively kill bone tumour cells whilst providing a base for bone regeneration. BAG was produced by a simple sol-gel technique assisted by EISA (Evaporation Induced Self-Assembly). Ball milling equipment was used to decrease the BAG particle size and increase its dispersibility. The powders were characterized by SEM (scanning electron microscopy), EDS (energy dispersive x-ray spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). IONPs were produced through chemical co-precipitation and coated with oleic acid to avoid aggregation and loss of superparamagnetic properties over time. First, PVP/BAG composite membranes were produced by electrospinning and the parameters were optimized to produce smaller fibres as it translates into higher surface area and higher bioactivity. IONPs were then incorporated in the solution. The electrospun membranes were crosslinked due to the PVP water-soluble characteristic. UV and thermal crosslinking were employed, but only thermal crosslinking proved to be successful. For this to be successful TGA/DSC was helpful to find the crosslinking temperature and provided information about the thermal stability of the membranes. Water-insoluble membranes were tested for magnetic hyperthermia application and cytotoxicity assays were also performed. The IONPs proved to have superparamagnetic properties and a small temperature variation was achieved for a 10 mg membrane sample, which proved the potential of composite membranes for this application.