Logic‐Based Strategy for Spatiotemporal Release of Dual Extracellular Vesicles in Osteoarthritis Treatment.

To effectively treat osteoarthritis (OA), the existing inflammation must be reduced before the cartilage damage can be repaired; this cannot be achieved with a single type of extracellular vesicles (EVs). Here, a hydrogel complex with logic‐gates function is proposed that can spatiotemporally controlled release two types of EVs: interleukin 10 (IL‐10)+ EVs to promote M2 polarization of macrophage, and SRY‐box transcription factor 9 (SOX9)+ EVs to increase cartilage matrix synthesis. Following dose‐of‐action screening, the dual EVs are loaded into a matrix metalloporoteinase 13 (MMP13)‐sensitive self‐assembled peptide hydrogel (KM13E) and polyethylene glycol diacrylate/gelatin methacryloyl‐hydrogel microspheres (PGE), respectively. These materials are mixed to form a "microspheres‐in‐gel" KM13E@PGE system. In vitro, KM13E@PGE abruptly released IL‐10+ EVs after 3 days and slowly released SOX9+ EVs for more than 30 days. In vivo, KM13E@PGE increased the CD206+ M2 macrophage proportion in the synovial tissue and decreased the tumor necrosis factor‐α and IL‐1β levels. The aggrecan and SOX9 expressions in the cartilage tissues are significantly elevated following inflammation subsidence. This performance is not achieved using anti‐inflammatory or cartilage repair therapy alone. The present study provides an injectable, integrated delivery system with spatiotemporal control release of dual EVs, and may inspire logic‐gates strategies for OA treatment. [ABSTRACT FROM AUTHOR]