Examenspresentation Oliver Forsell

Hydrogels as scaffolds for stem cell therapy with focus on cartilage

Opponent: Lisa Witte

Supervisor: Hanne Evenbratt and Marina Marinea

Examiner: Anna Ström

Abstract:

Osteoarthritis, a disease arising from degradation of articular cartilage in joints, presents a major cost for the healthcare system and is a leading reason behind work disability. Conventional therapies are temporary fixes with limit applications and an inability to fully restore the damaged tissue. In recent years, cell therapy has emerged as an alternative and regenerative cartilage therapy. Challenges remain in developing proper scaffolds which serve the purpose of protecting the cells and preventing migration while providing the right mechanical and biochemical signals ensuring high cell viability, proper differentiation and phenotype maintenance. In this study, hydrogel scaffolds were formulated with the objective to achieve both sufficient biochemical and mechanical properties by attempting to create an interpenetrating network (IPN) of polymers forming physical and covalent crosslinks. To determine whether an IPN could be obtained, gels with a variety of crosslinking degrees and polymer concentrations were formulated using a Box-Behnken design of experiments. The gelation kinetics were investigated using a rheometer and molded gels were mechanically tested with a universal testing machine as well as structurally characterized by fluorescent microscopy. A positive synergistic effect was observed with respect to the torsional elasticity but not for unconfined axial compression. Microstructure analysis revealed impact of polymer type and concentration on dispersion quality.   

Keywords: Hydrogels, crosslinking, osteoarthritis, cartilage, cell-therapy, alginate, rheology, microscopy