Shortening the early diagnostic window of Hg-induced liver injury with a HO-activated fluorescence/afterglow imaging assay.

Mercury ions (Hg) and mercury derivatives are a serious threat to ecosystems and human health due to their toxicity, and their toxicological effects are associated with a burst of reactive oxygen species (ROS) due to the oxidative stress. Endogenous hydrogen peroxide (HO), a featured ROS in vivo, plays an irreplaceable role in a significant number of pathological processes. However, the exact bioeffect role that HO plays in Hg-induced oxidative stress in a specific disease has not been well answered. In particular, optical imaging probes for HO endowed with afterglow emission properties are very rare. Here, the first fluorescence/afterglow probe (FA-HO) for accurate and specific detection of HO in cells, zebrafish, and mice under Hg-induced oxidative stress is reported. Moreover, FA-HO in its afterglow emission enables efficient monitoring of endogenous HO with a higher signal-to-noise ratio (SNR) in comparison to its fluorescence signals. More importantly, by virtue of the merits of afterglow emission that can eliminate autofluorescence, thus for the first time, shortening the diagnostic window of Hg-induced liver injury with FA-HO via noninvasive afterglow emission tracking of HO is achieved, which definitely provides a new opportunity and promising tool for early diagnosis of Hg-induced liver injury.