Evaluation of peroxynitrite fluxes in inflammatory mice with a ratiometric fluorescence probe

Inflammation is a critical physiological process in the human body, which is closely related to numerous disorders and cancers. ONOO^- is generated and functionalized in the inflamed process, but the roles of ONOO^- are still blurred. To illuminate the roles of ONOO^-, we fabricated an intramolecular charge transfer (ICT)-based fluorescence probe, HDM-Cl-PN, for the ratiometric determination of ONOO^- in the inflamed mouse model. The probe displayed a gradual fluorescence increase at 676 nm and a fluorescence drop at 590 nm toward 0-10.5 μM ONOO^-, and the ratio of 676 nm fluorescence and 590 nm fluorescence varied from 0.7 to 24.7. The significantly changed ratio and favorable selectivity ensure the sensitive detection of subtle changes in cellular ONOO^-. Thanks to the excellent sensing performance, HDM-Cl-PNin vivo ratiometrically visualized ONOO^- fluctuations in the LPS-triggered inflammatory process. Overall, this work not only expatiated the rational design for a ratiometric ONOO^- probe but also built a bridge to investigate the connections between ONOO^- and inflammation in living mice.