Investigation of Different Crosslinking Strategies to Develop 3D Polymer Scaffolds for Cartilage Tissue Engineering

Scaffolds play an important role in cartilage tissue engineering as they can support regeneration of the damaged tissue which cannot be restored by standard medical interventions. Collagen type I and its denatured form, gelatin are widely used biomaterials in scaffolds' synthesis due to their high biodegradability and biocompatibility. However, without suitable stabilization, these natural polymers can degrade quickly in the physiological conditions as well as under mechanical load. In order to enhance chemical stability, structural integrity and stiffness of the biomaterials, different crosslinking methods (reinforcements) were applied to produce 3D porous polymeric scaffolds. The first part of my work was focused on developing 3D gelatin scaffolds through stabilization by physical (DHT), chemical (BDDGE) and natural (Genipin) crosslinking approaches. The comparative analysis among these three different constructs were assessed by investigating scaffold's microstructure, porosity, degradation rate and mechanical behaviour. Additionally, cytocompatibility, bioactivity and overall cell-scaffold interaction was verified using human osteoblast-like cells and human chondrocytes. The second part of this thesis aimed to investigate the effectiveness of non-enzymatic crosslinking by ribose glycation to improve stability and rigidity of type I collagen matrices. The main objectives were to determine optimal conditions of this novel crosslinking approach and to deeply characterize the 3D porous collagen scaffolds stabilized by two different crosslinking strategies: PRE- and POST-crosslinking. Both studies presented in this work exhibited feasibility to develop 3D scaffolds with proper interconnected porosity, resistance to degradation and mechanical load as well as cytocompatibility and rich cartilage components deposition in vitro. Benefits and limitations of each crosslinking method have been demonstrated highlighting the DHT treatment and POST-glycation as the most suitable crosslinking strategies to develop 3D scaffolds for cartilage regeneration.