With the improvement of tissue engineering and waiting to find a suitable scaffold to guide the growth of new tissues, hydrogels play an important role as they can absorb large quantities of water and physiological liquids. Furthermore, their peculiar characteristics are: they show excellent biocompatibility and the probability of causing inflammatory responses, thrombosis and tissue damage is also minimal. The hydrophilic but cross-linked structure gives them the ability to absorb large quantities of water without dissolving the polymer. These unique characteristics make them an appropriate substitute for soft and connective tissues. Furthermore, hydrogels have high permeability to oxygen, nutrients, and other water-soluble metabolites. There are two sources of polymers for scaffolds, natural and synthetic. The advantages of natural scaffolds are their excellent biocompatibility, cell-controlled degradability, and intrinsic cell interaction. Their disadvantage is the limited range of mechanical properties. On the other hand, synthetic polymers with precisely controlled structures and functions can be prepared. All in all, due to the characteristics of the hydrogel and their structural similarity to the macromolecular-based components of the body, they are a good candidate for the scaffold of cartilage regeneration. To design a scaffold, attention must be paid to physical and biological parameters. For example, the biological parameters are referred to as the cell adhesion capacity of the hydrogel, and the main important physical parameters are the degradation and mechanics of the scaffold. It is believed that degradation rates of tissue scaffolds should be the same as cellular processes. Another characteristic of hydrogels is...... middle of paper...... glycosaminoglycan, composed of N-acetyl-d-glucosamine and d-glucuronic acid. HA is the major component of the ECM in connective tissues and is abundant in vitreous and synovial fluid. HA enhances the proliferation and differentiation of progenitor cells. It is a mucopolysaccharide present in various types of tissues and its immunoneutrality makes it an excellent building block for biomaterials to be used for tissue engineering and drug delivery system. Knudson et al. determined that hyaluronic oligosaccharides induced chondrocyte chondrolysis, including near-total loss of the proteoglycan-rich stainable matrix and activation of gelatinolytic activity. HA is known to interact with chondrocytes via various surface receptors including CD44. The HA-bound surface receptor activates a sophisticated signaling pathway that causes chondrocytes to maintain their original phenotype.