摘要Mesenchymal stem cells(MSC)are particularly effective in promoting cartilage regeneration due to their immunomodulatory,anti-inflammatory and regenerative repair functions of tissues and organs.Meanwhile,the intra-articular delivery and synergy with other therapeutic drugs have been the key issues driving their further application.We report a mussel-inspired multifunctional hydrogel system,which could achieve co-delivery and synergism effect of MSC-derived exosomes(Exos)with icariin(ICA).The ICA and Exos co-delivered articular cavity injection system are expected to retain in the joint cavity and promote cartilage regeneration,due to the thermosensitive,self-healing and adhesion properties of the mussel-inspired multifunctional hydrogel.The experimental results proved that Exos enhanced the cellular uptake of ICA by more than 2-fold evenly,and the synergism of Exos and ICA efficiently improve the cell proliferation and migration.After synergic treatment,the content of matrix metalloproteinase 13 in the supernatant and intracellular decreased by 47%and 59%,respectively.In vivo study,ICA-loaded Exos exhibited prolonged retention behavior by multifunctional hydrogel delivery,thus displayed an increased cartilage protection.In the model of osteoarthritis,co-delivery hydrogel system relieved the cartilage recession,ensuring appropriate cartilage thickness.