Articular cartilage defects can be caused by disease,trauma,or sports-related injury.Without blood vessels,lymphatic and nerve tissue,the damaged articular cartilage shows limited capacity of self-repair.Tissue engineering provides a promising approach in the treatment of cartilage defects [1].This approach generally involves the use of three-dimensional scaffolds,which can support the growth,proliferation and differentiation of seeded cells.Hydrogels are three-dimensional hydrophilic polymer networks retaining a large amount of water.Due to physical properties that resemble the native extracellular matrix (ECM),hydrogels are considered suitable scaffolds for cartilage tissue engineering [2].