In improving 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 fluids. In addition, their special characteristics are: excellent biocompatibility and minimal probability of causing inflammatory responses, thrombosis and tissue damage. The hydrophilic but cross-linked structure gives them the ability to absorb a large quantity of water without dissolving the polymer. These unique characteristics make it a suitable substitute for soft and connective tissues. Additionally, hydrogels have high permeability to oxygen, nutrients, and other water-soluble metabolites. There are two sources of scaffolding polymer, natural and synthetic. The advantages of natural scaffolds are their excellent biocompatibility, cell-controlled degradability, and intrinsic cell interaction. Their disadvantage lies in their limited range of mechanical properties. On the other hand, synthetic polymers can be prepared with precisely controlled structures and functions. From all of the above, due to the hydrogel characteristics and their structural similarity to macromolecular components of the body, they are good candidates for scaffolding cartilage regeneration. In order to design a scaffold, attention should be paid to physical and biological parameters. For example, the biological parameters are shown as the ability of the hydrogel to adhere to cells and the main important physical parameters are the degradation and mechanics of the scaffold. It is believed that the degradation rates of tissue scaffolds should be the same as those of cellular processes. Another characteristic of hydrogels is...... middle of paper ......ted glycosaminoglycan, composed of N-acetyl-d-glucosamine and d-glucuronic acid. HA is the major component of ECM in connective tissues and is abundant in vitreous and synovial fluids. 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 hyaluronan oligosaccharides induced chondrocyte chondrolysis, including near-total loss of proteoglycan-rich matrix and activation of gelatinolytic activity. HA is known to interact with chondrocytes via various surface receptors, including CD44. HA-bound surface receptor triggers a sophisticated signaling pathway allowing chondrocytes to maintain their original phenotype.