Figure 5.

Click chemistry‐mediated crosslinked hydrogel. A) Formation of cartilage‐mimetic injectable hydrogel utilizing the photo‐clickable thiol–ene reaction between multiarm PEG norbornene monomer and crosslinker PEG dithiol, along with the incorporation of extracellular matrix mimetics of chondroitin sulfate, RGD, and HMSCs. Hydrogel with chondroitin sulfate when combined with dynamic compressive loading acted as a potent physiochemical cue to the cartilage environment upregulating p38 MAPK and downregulating SMAD 1/5/8 signaling pathways maintaining stable HMSCs chondrogenesis for cartilage repair. B) Encapsulation of chondrocytes progenitor cells in HA‐SH and HB‐PEG injectable hydrogel crosslinked via thiol–ene click chemistry for cartilage regeneration. The porous hydrogel promoted the extracellular matrix synthesis function of the encapsulated cells and downregulated gene expression related to inflammation for treating osteoarthritis. C) In situ crosslinking of chondroitin sulfate with PEG monomers using Diels–Alder reaction. Hydrogels containing ChS decreased the expression of TNFα and IL‐1β, and favored chondrogenesis of encapsulated cells.