Visualization of endogenous hypochlorous acid during ferroptosis based on Rhodamine B fluorescent probe.

Hypochlorous acid (HClO) plays critical roles in ferroptosis process and the specific molecular mechanism related to it is still obscure. To reveal HClO fluctuation in the ferroptosis cells, a fluorescence turn-on probe RDM-577 that can detect intracellular HClO was skillfully engineered. The probe exhibited a substantial fluorescence enhancement in response to HClO (F/F0 = 35), enabling sensitive detection of HClO in both in vitro and in vivo environments. Additionally, it demonstrated remarkable performance characteristics, such as an exceptionally low detection limit (5.8 nM). Consequently, the probe effectively tracks dynamic changes of HClO levels in ferroptosis cells. By imaging HClO fluctuations during ferroptosis, we observed that GSH protects against GPX4 degradation triggered by ferroptosis inducers. Notably, RDM-577 precisely identifies inflammatory sites in vivo and exhibits strong fluorescence in a mouse model of hepatitis. The work yielded a fluorescence turn-on probe designed for intravital imaging of HClO within ferroptosis cells, offering potential for extending its use to investigate the specific molecular mechanisms underlying ferroptosis.