(116af) Tailoring Biomimetic Collagen-Poly(vinyl alcohol) Hydrogels for Articular Cartilage Repair

Every year, over 600,000 people seek treatment for articular cartilage damage (often repeat procedures), at a cost of $15 billion to the economy. This has motivated the investigation of poly(vinyl alcohol) (PVA) hydrogels as a replacement material for articular cartilage. By mixing PVA with organic solvents and then exposing the emulsions to physically-crosslinking freeze-thaw cycles, PVA solutions can be made into solid porous scaffolds without the use of chemical cross-linkers. This study investigated the effects of synthesis parameters (mixing speed and level & type of organic solvent) on the pore structure and mechanical properties of PVA hydrogels. This research also examined the swelling behavior of the hydrogels over a four week period in a solution simulating the internal environment of articular cartilage. Finally, in an effort to create a bioactive scaffold, type-II collagen was blended into the PVA hydrogels. The presence of active collagen was assessed with an immunohistochemical stain, and cell adhesion tests were run with mesenchymal stem cells. The results confirm the possibility of tailoring the material properties of PVA scaffolds based on synthesis parameters. The swelling experiments point to potential stiffening problems of the hydrogels in solution. Also, while previous studies have concentrated on coating PVA hydrogel surfaces with proteins through chemical or UV treatments, these experiments show the possibility of introducing a bioactive protein throughout the hydrogel scaffold without chemical biproducts.