Alkaline phosphatase-instructed self-assembling supramolecular glucosamine hydrogel for osteoarthritis treatment

Osteoarthritis (OA) is the most prevalent musculoskeletal disorder, affecting hundreds of millions of people worldwide. Glucosamine (GlcN) has been shown to effectively reduce proteoglycan degradation, attenuate articular cartilage degeneration and joint space narrowing, and alleviate osteoarthritis-related pain. However, the use of GlcN as a long-term medication for alleviating osteoarthritis is limited by its short half-life. Herein, we employed an enzyme-instructed self-assembly (EISA) strategy to construct a prodrug molecule, TP-(P)-G, containing a glucosamine (GlcN) moiety, which forms the supramolecular hydrogel TP-G under alkaline phosphatase (ALP) catalysis for OA treatment. Physicochemical characterization demonstrated that the hydrogel self-assembles into structurally stable nanofibrous networks exhibiting optimal viscoelastic behavior. In vitro evaluation revealed TP-G potently upregulated proteoglycan production in chondrocytes—with no significant cytotoxicity observed at biologically relevant doses. Subsequent in vivo studies established that TP-(P)-G administration significantly reduced key inflammatory cytokine concentrations, attenuated cartilage degeneration, and ameliorated synovitis and gait impairment in rats. Micro-CT and histological examinations provided further evidence of the hydrogel's protective effects on cartilage matrix and the subchondral bone interface, indicating that TP-G helps maintain the structural integrity of the joint. Additionally, H&E staining of major organs revealed no observable pathological abnormalities, confirming the hydrogel's excellent biocompatibility and systemic safety. Collectively, these findings establish ALP-instructed self-assembly of TP-(P)-G into TP-G hydrogel as a disease-modifying strategy for OA, offering strong anti-inflammatory properties and chondroprotective benefits that could open new avenues for clinical intervention.