R. Polez Teixeira: Tailoring the properties of polysaccharides-based hydrogels

Abstract: 

This thesis focused on developing polysaccharides-based hydrogels designed to closely mimic the properties of the human extracellular matrix (ECM) through innovative 3D biofabrication techniques. While nanocellulose hydrogels have shown promise in the fields of biomedical engineering and regenerative therapy, they face challenges related to poor mechanical properties and limited 3D printing resolution. To overcome these challenges, nanocellulose was combined with heteropolysaccharides (tragacanth gum, xanthan gum, and quince seed mucilage). This strategic combination enhanced the processability of the hydrogels by improving their viscosity and shear-thinning behavior, ensuring smooth extrusion and deposition through the printing nozzle. These hydrogels closely resemble the scaffolds typically used in biomedical applications in terms of their porosity, pore size, and porous structure. Additionally, adjusting the nanocellulose content enabled tailoring the stiffness and swelling of the hydrogel, allowing further optimization according to the specific intended application. Furthermore, the study explored controlled drug delivery, particularly the development of chitosan (CS) hydrogels enriched with the phenolic compound phloroglucinol (PG). These hydrogels exhibited versatility, as they could be prepared with varying porosities and morphologies, resulting in distinct release kinetics. This versatility positions them as suitable biocompatible scaffolds and drug delivery systems, particularly for applications like wound dressing. In addition, the research delved into the molecular-level interactions between biomaterials and living cells using advanced Atomic Force Microscopy-based techniques such as colloidal probe microscopy (CPM), and single-cell force spectroscopy (SCFS). These results revealed insights into cell-biomaterial and cell-cell interactions, shedding light on adhesion protein dependencies and cellular behaviors within different biomaterial environments. In summary, this study advanced polysaccharides-based hydrogels for biomedical applications, combining innovative fabrication strategies with a deep understanding of molecular-level interactions. The findings have the potential to significantly impact biomedical research, paving the way for high-performance functional materials in various biomedical domains.

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Opponent: Professor Aji Mathew, Stockholm University, Sweden

Supervisor: Professor Monika Österberg,  Aalto University, Department of Bioproducts and Biosystems

Link to electronic thesis: Tailoring the properties of polysaccharides-based hydrogels - From cell interactions to biomedical applications