Engineering cartilage in a photochemically crosslinked collagen gel.

This study's purpose was to investigate whether photochemically crosslinking collagen gel to encapsulate chondrocytes (articular, auricular, costal) would permit new cartilage formation in vivo, and to determine whether this neocartilage had the ability to integrate with existing native cartilage. Chondrocytes from swine were embedded in collagen gel that was photochemically crosslinked using riboflavin and visible light. Controls were collagen gels containing cells that were not crosslinked. Cylindrical implants (0.1 cc) were placed in athymic mice for 4 and 8 weeks. To study integration, the constructs were crosslinked within articular cartilage rings and implanted in the mice. Samples were analyzed in terms of macroscopic, microscopic, and biochemical aspects. Photocrosslinking did not affect the amount of glycosaminoglycan and type II collagen produced by the cells. We found that photochemical crosslinking collagen gel enhances the physical parameters of the gel and permits new cartilage formation that can integrate with existing native cartilage.