Bioorthogonal dual-channel imaging of NO and H2S reveals redox imbalance in atherosclerotic plaques.

Redox imbalance is closely associated with atherosclerosis (AS), but tools for precise, simultaneous, and in situ imaging of oxidative NO and reductive H2S within the AS plaque microenvironment are still lacking. Herein, we developed a bioorthogonal small-molecule fluorescent probe, DBCO-BOD-NH, for dual-channel imaging of NO and H2S. The probe is built on a BODIPY fluorophore, incorporates a dibenzocyclooctyne (DBCO) bioorthogonal group, and combines metabolic labeling with an unnatural sugar (N3-AC4GlcN). Through a "recognition-reporting" separation strategy, it achieves high signal-to-noise, synchronous imaging of both gasotransmitters in the plaque microenvironment. In vitro, the probe exhibits excellent optical properties, high selectivity, and good photostability. Cellular imaging reveals a dynamic inverse evolution during macrophage-to-foam cell transformation: NO levels gradually increase while H2S levels decrease. In animal models of AS and diabetes-combined AS, plaque progression is accompanied by increased NO and decreased H2S levels, and diabetes further exacerbates the NO-H2S redox homeostasis imbalance. This study not only provides a dual-channel imaging tool to investigate the dynamic evolution of NO-H2S imbalance in the AS plaque microenvironment, but also offers reliable evidence for the direct involvement of gasotransmitters in diabetes-accelerated AS progression.