Effect of visco-elastic silk-chitosan microcomposite scaffolds on matrix deposition and biomechanical functionality for cartilage tissue engineering.

Commonly used polymer-based scaffolds often lack visco-elastic properties to serve as a replacement for cartilage tissue. This study explores the effect of reinforcement of silk matrix with chitosan microparticles to create a visco-elastic matrix that could support the redifferentiation of expanded chondrocytes. Goat chondrocytes produced collagen type II and glycosaminoglycan (GAG)-enriched matrix on all the scaffolds (silk:chitosan 1:1, 1:2 and 2:1). The control group of silk-only constructs suffered from leaching out of GAG molecules into the medium. Chitosan-reinforced scaffolds retained a statistically significant (p < 0.02) higher amount of GAG, which in turn significantly increased (p < 0.005) the aggregate modulus (as compared to silk-only controls) of the construct akin to that of native tissue. Furthermore, the microcomposite constructs demonstrated highly pronounced hysteresis at 4% strain up to 400 cycles, mimicking the visco-elastic properties of native cartilage tissue. These results demonstrated a step towards optimizing the design of biomaterial scaffolds used for cartilage tissue engineering.