Ingenious Synergy of a Pathology‐Specific Biomimetic Multifunctional Nanoplatform for Targeted Therapy in Rheumatoid Arthritis

Abstract Based on the pathological characteristics of rheumatoid arthritis, including the overproduction of reactive oxygen species (ROS), inflammatory responses, and osteoclast differentiation, a biomimetic multifunctional nanomedicine (M‐M@I) is designed. Iguratimod (IGU) is loaded, which inhibits inflammatory responses and osteoclast differentiation, into mesoporous polydopamine (MPDA), which scavenges ROS. Subsequently, the nanoparticles are coated with a cell membrane of macrophages to achieve actively targeted delivery of the nanoparticles to inflamed joints. It is shown that the M‐M@I nanoparticles are taken up well by lipopolysaccharide‐induced RAW 264.7 macrophages or bone marrow‐derived macrophages (BMDMs). In vitro, the M‐M@I nanoparticles effectively scavenge ROS, downregulate genes related to inflammation promotion and osteoclast differentiation, and reduce the proinflammatory cytokines and osteoclast‐related enzymes. They also reduce the polarization of macrophages to a pro‐inflammatory M1 phenotype and inhibit differentiation into osteoclasts. In mice with collagen‐induced arthritis, the M‐M@I nanoparticles accumulate at arthritic sites and circulate longer, significantly mitigating arthritis symptoms and bone destruction. These results suggest that the pathology‐specific biomimetic multifunctional nanoparticles are effective against rheumatoid arthritis, and they validate the approach of developing multifunctional therapies that target various pathological processes simultaneously.