Cartilage lesions are common and could lead to osteoarthritis. Current therapies not only fail to mimic the characteristics of natural articular cartilage, they are limited to specific age groups, lesion sites or sizes. Therefore, a tissue engineered construct could be an ideal solution. The idea of the proposed solution is based on the mechanism employed in natural cartilage, mimicking the tension in collagen fibers created by the osmotic swelling of the extracellular matrix using a silk scaffold, restricting a high swelling poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogel.
The aim of this thesis was to study whether the combination of a PEGDMA hydrogel with a silk scaffold increases the mechanical properties compared to the individual components and if this construct was suitable for chondrocyte encapsulation. With this aim in mind, the report includes a method for the preparation of a porous silk scaffold with a silk top and bottom layer to seal off these surfaces to ensure a proper restriction of the swelling hydrogel. Moreover, the introduction and polymerization method of a PEGDMA hydrogel in this porous scaffold was optimized regarding the UV exposure. Restricted swelling was measured using free swelling PEGDMA hydrogels and hydrogels injected in the silk scaffold. To alter the swelling and the effect on the restriction, varying salt concentration of the bathing solution were used and monitored using indentation tests. Finally, an assessment of the suitability of the construct for cell encapsulation was performed using histological images for viability tests and cell distribution.
A successful approach was developed for preparation of a confining silk scaffold with covered top and bottom surfaces. Next, optimal UV exposure was determined for sufficient crosslinking of the hydrogel loaded scaffold. Furthermore, the confined construct revealed restricting properties of 69.5% compared to free swelling hydrogel samples. The combination of these two materials showed a synergistic effect on the mechanical properties, with an initial modulus of 657±225 kPa and equilibrium modulus of 267±111 kPa in unswollen state, which are within the lower range of native cartilage. Finally, the construct demonstrated a suitable environment for encapsulated chondrocytes.