A Magnetic Apoptotic Body‐Loaded Triblock Hydrogel Amplifies Efferocytosis for Hyaline Cartilage Regeneration

ABSTRACT

Articular cartilage injury remains a refractory clinical challenge because chronic inflammatory microenvironments impede functional hyaline cartilage regeneration. We identified impaired efferocytosis by synovial macrophages as a mechanism that perpetuates inflammation and compromises effective cartilage repair. To address this limitation, we developed a magnetic engineering strategy by anchoring superparamagnetic Fe ₃ O ₄ nanorods onto neutrophil apoptotic bodies to generate FP‐NABs, which were subsequently loaded into an injectable thermosensitive hydrogel (PFN), to enable sustained intra‐articular release and in situ retention. Under external magnetic field stimulation, PFN amplified macrophage efferocytosis, suppressed M1 polarization, and enhanced anti‐inflammatory signaling in vitro. In a rat osteochondral defect model, PFN remodeled the synovial microenvironment, recruited endogenous bone marrow stem cells, and promoted fibrocartilage hyalinization, ultimately redirecting the repair process toward hyaline cartilage regeneration. This work establishes a causal link between restored efferocytosis and high‐quality cartilage repair, and provides a translatable magnetic‐immune engineering platform for hyaline cartilage regeneration.