Intra-Articular Injection of PLGA/Polydopamine Core–Shell Nanoparticle Attenuates Osteoarthritis Progression

Osteoarthritis (OA) is a common joint disease characterized by progressive cartilage degeneration. Unfortunately, currently available clinical drugs are mainly analgesics and cannot alleviate the development of OA. Kartogenin (KGN) has been found to promote the differentiation of bone marrow mesenchymal stem cells (BMSCs) into chondrocytes for the treatment of cartilage damage in early OA. However, KGN, as a small hydrophobic molecule, is rapidly cleared from the synovial fluid after intra-articular injection. This study synthesized a KGN-loaded nanocarrier based on PLGA/polydopamine core/shell structure to treat OA. The fluorescence signal of KGN@PLGA/PDA-PEG-E7 nanoparticles lasted for 4 weeks, ensuring long-term sustained release of KGN from a single intra-articular injection. In addition, the polyphenolic structure of PDA enables it to effectively scavenge reactive oxygen species, and the BMSC-targeting peptide E7 (EPLQLKM) endows KGN@PLGA/PDA-PEG-E7 NPs with an effective affinity for BMSCs. As a result, the KGN@PLGA/PDA-PEG-E7 nanoparticles could effectively induce cartilage in vitro and protect the cartilage and subchondral bone in a rat ACLT model. This therapeutic strategy could also be extended to the delivery of other drugs, targeting other tissues to treat joint diseases.