A novel LD-targeting cysteine-activated fluorescent probe for diagnosis of APAP-induced liver injury and its application in food analysis

Cysteine (Cys) not only plays an indispensable role in maintaining the redox balance in organisms, but is also an important nutrient in the food industry. Fluorescence-based detection systems have emerged as an effective method to track the locations and concentrations of different species. To achieve efficient monitoring of Cys in both food samples and biological systems, a novel lipid droplet (LD) targeted fluorescent probe (namely NIT-Cys) was constructed for the turn-on detection of Cys, characterized by a large Stokes shift (142 nm), a short response time (<8 min), and a low Cys detection limit (39 nM). Furthermore, the NIT-Cys probe has been successfully used not only to quantify the amounts of Cys in selected food samples, but also to enable the visualization of endogenous Cys in acetaminophen (APAP)-induced drug-induced liver injury cells, zebrafish larvae and mice models. Consequently, the work presented here provides an efficient tool for monitoring Cys.