A Superparamagnetic Composite Hydrogel Scaffold as in Vivo Dynamic Monitorable Theranostic Platform for Osteoarthritis Regeneration.

Osteoarthritis is a prevalent disease, characterized by subchondral fractures in its initial stages, which has no precise and specific treatment now. In this study, a novel multifunctional scaffold was synthesized by photopolymerizing glycidyl methacrylate-modified hyaluronic acid as the matrix in the presence of hollow porous magnetic microspheres based on hydroxyapatite. In vivo subchondral bone repairing results demonstrate that the scaffold's meticulous design has the most suitable properties for subchondral bone repair. The porous structure of inorganic particles within the scaffold facilitates efficient transport of loaded exogenous vascular endothelial growth factor. The Fe 3 O 4 nanoparticles assembled in the microspheres could promote the osteogenic differentiation of bone marrow mesenchymal stem cells and accelerate the generation of new bone. These features enable the scaffold to exhibit favorable subchondral bone repair properties and attain high cartilage repair scores. The therapy results prove that the subchondral bone support considerably influences the upper cartilage repair process. Furthermore, magnetic resonance imaging monitoring demonstrates that Fe 3 O 4 nanoparticles, which were gradually replaced by new bone during osteochondral defect repair, allow a noninvasive and radiation-free assessment to track the newborn bone during the osteoarthritis repair process. The composite hydrogel scaffold provides a versatile platform for biomedical applications in osteoarthritis treatment. This article is protected by copyright. All rights reserved.