Red emissive carbon dots Self-Cascading antioxidant nanozymes combine with anti-miRNA-155 for accurate monitoring and ameliorating rheumatoid arthritis.

• A nanoplatform (CS-CDs@155) for rheumatoid arthritis accurate monitoring and amelioration was fabricated. • CS-CDs@155 effectively scavenges intracellular reactive oxygen species and downregulates pro-inflammatory cytokines. • CS-CDs@155 realize macrophage subphenotype identification via miRNA-155 ratiometric imaging. • CS-CDs@155 regulate the polarization of proinflammatory macrophages. Accurate monitoring and effective antioxidant treatment strategies are highly desirable in rheumatoid arthritis (RA) amelioration. Herein, cerium (Ce) and selenium (Se) co-doped carbon dots (CS-CDs) integrated superoxide dismutase (SOD)-like and glutathione peroxidase (GPx)-like self-cascading catalytic activity are engineered. In this self-cascading nanozymes system, Ce active center catalyzes ·O 2 − to H 2 O 2 by mimicking SOD, and the adjacent Se component sequentially decomposes the H 2 O 2 by mimicking GPx, achieving enhanced catalytic and superior reactive oxygen species (ROS)-scavenging activities. CS-CDs further load cyanine-5 (Cy5)-labeled anti-miRNA-155 to realize macrophage subphenotype identification via miRNA-155 ratiometric imaging for RA accurate monitoring, and regulate the polarization of pro-inflammatory macrophages for synergistic RA amelioration. Comprehensive in vitro and in vivo experiments validate the advanced RA monitoring and therapy performance of the self-cascading nanozymes. This work not only offers a rationally designed self-cascading nanozyme with simple structures and intriguing ROS-scavenging capacity, but also opens up a strategy for accurate RA monitoring and synergistic amelioration. [ABSTRACT FROM AUTHOR]