A novel fluorescent sensing strategy for point-of-care monitoring of Hg2 +-induced oxidative stress in HeLa cells, zebrafish and mice models

Hg 2+ -induced oxidative stress is an important pathway mediating biotoxicity, and the dynamics of reactive oxygen/nitrogen species (ROS/RNS) is a key indicator for quantitatively assessing the level of oxidative stress. Herein, a novel “targeted dual recognition” NIR fluorescent chemosensor (DDPT) was constructed for the specific recognition of Hg 2+ and ONOO - . The DDPT activated by Hg 2+ for the detection of ONOO - exhibited rapid response (<50 s), high sensitivity (16.8 nM) and excellent selectivity. The P = S bond in DDPT is oxidized to P = O by Hg 2+ , followed by ONOO - the specific attack on the P-O bond to break it, releasing the DDPT-OH to generate a significant fluorescence enhancement (with a Stokes shift up to 188 nm). The response mechanism of DDPT was systematically verified by 1 HNMR, HRMS and DFT theoretical calculations. Furthermore, DDPT was successfully evaluated for imaging Hg 2+ -induced ONOO - dynamics in cellular, zebrafish and mouse models due to its advantages of low cytotoxicity, high tissue permeability and biocompatibility. The results reveal that Hg 2+ induces oxidative stress and increases ONOO - concentration to destroy the antioxidant defense system of organisms, thus triggering the toxic pathway of oxidative stress. The development of DDPT provides a basis for analyzing pollutant-oxidative stress interactions, assessing health risks, and developing targeted intervention strategies.