This thesis focuses on electron irradiated gelatin hydrogel composites for the development of a magnetically-controllable material. Smart materials comprised of magnetic nanoparticles embedded in hydrogels are known as ferrogels. Deformation, swelling and viscoelasticity of ferrogels can be controlled by external magnetic fields, with potential applications in drug delivery, tissue engineering, actuation and sensing.
High energy electron irradiation was used to create stable gelatin hydrogels. Geometry, swelling, solubility and viscoelasticity were experimentally quantified for the irradiated gelatin. The degree of crosslinking and mesh size were calculated by theories of rubber elasticity and Flory-Rehner. Fourier transform infrared spectroscopy was used to confirm minimal chemical changes occurred as a result of crosslinking. The micro- and nanostructure of the hydrogels were investigated using small-angle X-ray scattering to supplement macroscopic investigations, allowing for comparison of experimental data with additional semiflexible polymer models.
The cytotoxicity of the irradiated hydrogels and liquid byproduct were analyzed using NIH 3T3 mouse embryonic fibroblasts and human umbilical vein endothelial cells. The influence of the degree of crosslinking on cellular morphologies was also explored. Additionally, surface wettability and hydrogel degradation times were quantified with respect to the irradiation dose. Preliminary experiments examined the potential of irradiated gelatin hydrogels as components of vascular scaffolds. Potential surface modification strategies to enhance and direct cellular interactions were briefly explored, such as surface coating and patterning.
After integration of magnetic nanoparticles into the gelatin, the magnetic response of the ferrogels was investigated using magnetic particle spectroscopy and magnetorelaxometry. These techniques were highly sensitive to the changing matrix viscoelasticity around the sol-gel transition. Irradiated ferrogels exhibited thermal stability across the sol-gel transition, although some local softening was observed. This research highlights the potential of electron irradiated gelatin hydrogels and ferrogels, while providing fundamental insights into the physical processes influencing the network structure, mechanics and resulting cellular interactions.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:15845 |
| Date | 10 July 2017 |
| Creators | Wisotzki, Emilia |
| Contributors | Universität Leipzig |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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