Articular cartilage is aexible and connective tissue in which the chondrocytes are sparsely distributed into a highly organized extracellular matrix (ECM) rich in proteoglycans, glycosaminoglycans (GAGs), and collagen bers. The repair of cartilage damage, which occurs as a result of injury, disease, trauma and tumor, is one of the most challenging clinical problems in orthopedics.
The low repair capacity of cartilage is attributed to the lack of chondrocyte mobility in the ECM and the absence of progenitor cells and vascular networks.
Among different scaffolds being developed for cartilage regeneration, hydrogels are of great interest due to their interesting properties that can mimic the physiochemical and biological properties of the native hydrated cartilage ECM.
Injectable hydrogels, which arein situformed aer injection at the defect site, have received much attention in recent years.
The injectable nature of these hydrogels provides the attractive feature of facile and homogenous cell distribution within any defect size or shape prior to gelation in good alignment with the surrounding tissue by a simple minimally invasive injection procedure.
Thermosensitive hydrogels as specic injectable biomaterials can undergo reversible sol–gel transitions upon exposure to physiological temperature