3D printed hydrogels based on polysaccharides and magnetic nanoparticles for biomedical applications

• Main Author: Calado, Beatriz
• Publication Date: 2024
• Format: Master thesis
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10362/168833
• topic: Impressão 3D; quitosano; nanocelulose; fotopolimerização; SPIONs; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Médica

Cancer is one of the most significant challenges humanity faces nowadays. The most commonly applied therapies, like chemotherapy, are not specific for tumour cells, causing systemic toxicity. Drug delivery systems are an approach to avoid these effects. Hydrogels, polymeric crosslinked matrices, are widely studied for this application due to their advantageous characteristics, like matrices porosity and swelling capacity. Hydrogels can be processed by 3D bioprinting, a technique to develop layer-by-layer structures through software-controlled bioink deposition, enabling customized systems for drug delivery applications. Hydrogels may also be coupled with Superparamagnetic Iron Oxide Nanoparticles (SPIONs). In a therapeutic approach named magnetic hyperthermia, these NPs cause the tumour temperature to rise when subjected to an Alternating Magnetic Field (AMF). This master thesis developed 3D bioprinted methacrylate chitosan (ChMA) hydrogels reinforced with Cellulose Nanocrystals (CNC) with SPIONs incorporated. The successful methacrylation process of ChMA was confirmed through chemical characterization, while thermal analysis indicated a lower decomposition temperature compared to chitosan. Subsequently, bioink formulations incorporating ChMA, CNC, and Irgacure 2959 as the photoinitiator were developed and assessed rheologically, demonstrating shear-thinning behaviour and increased viscosity with higher ChMA and CNC concentrations. Based on these findings, two formulations were selected for 3D bioprinting, with one yielding successful outcomes after optimization of printing parameters, UV light exposure, and photopolymerization mechanisms. This formulation was used to produce bulk hydrogels for characterization purposes. Mechanical tests on the obtained structures provided insights into their compression behaviour, while morphological analysis via Scanning Electron Microscopy (SEM) revealed a porous matrix with homogeneous CNC distribution. PBS absorption tests indicated rapid phosphate buffered saline uptake followed by stabilization. Despite initial attempts, the addition of SPIONs to the hydrogels was unsuccessful in achieving photocrosslinked structures or bulk hydrogels. This work represents an early stage in the development of a novel 3D bioprinted system, encompassing material synthesis, bioink formulation, bioprinting processes and bioink and structure characterization.