Precise Lubrication and Protection of Cartilage Damage by Targeting Hydrogel Microsphere

Abstract Osteoarthritis (OA) is a degenerative bone and joint disease characterized by decreased cartilage lubrication, leading to continuous wear and ultimately irreversible damage. This situation is particularly challenging for early‐stage OA, as current bio‐lubricants lack precise targeting for small inflammatory lesions. In this work, an antibody‐mediated targeting hydrogel microspheres (HMS) is developed to precisely lubricate the local injury site of cartilage and prevent the progression of early OA. Anti‐Collagen type I (Anti‐Col1) is an antibody that targets cartilage injury sites in early OA stages. It is anchored on a HMS matrix made of Gelatin methacrylate (GelMA) and poly (sulfobetaine methacrylate) (PSBMA) to create targeted HMS (T‐G/S HMS). The T‐G/S HMS's high hydrophilicity, along with the dynamic interaction between its surficial Anti‐Col1 and the Col1 on cartilage injury site, ensures its precise and effective lubrication of early OA lesions. Consequently, injecting T‐G/S HMS into rats with early OA significantly slows disease progression and reduces symptoms. In conclusion, the developed injectable targeted lubricating HMS and the precisely targeted lubrication strategy represent a promising, convenient technique for treating OA, particularly for slowing the early‐stage OA progression.