Silk fibroin scaffolds were studied as a new biomaterial option for tissue engineered
cartilage-like tissue. Human bone marrow derived mesenchymal stem cells (MSC)
were seeded on silk, collagen, and cross-linked collagen scaffolds and cultured for 21
days in serum free chondrogenic medium. Cells proliferated more rapidly on the silk
fibroin scaffolds when compared to the collagen matrices. The total content of
glycosaminoglycan (GAG) deposition was three times higher on silk when compared
to collagen scaffolds. GAG deposition coincided with overexpression of type II
collagen and aggrecan genes. Cartilage-like tissue was homogeneously distributed
throughout the entire silk scaffolds, while on the collagen and cross-linked collagen
systems tissue formation was restricted to the outer rim leaving a doughnut
appearance. Round or angular-shaped cells resided in deep lacunae in the silk systems
and stained positively for type II collagen. The aggregate modulus of the tissue
engineered cartilage constructs was more than two-fold higher when compared to the
unseeded silk scaffold controls. These results suggest that silk fibroin scaffolds are
suitable biomaterial substrates for autologous cartilage tissue engineering in serum free
medium and enable mechanical improvements along with compositional features
suitable for durable implants to (re)generate cartilage.