AIE and ICT Synergistic Lysosome-Targeted Ratiometric Fluorescence Sensor for the Detection and Imaging of Th<sup>4+</sup> in the Liver of Zebrafish and Mice
Qinghua Hu, Cen Tang, Yuting Yin, Xiang‐he Kong, Chaowei Fu, Rong Hu, Hongqing Wang
Abstract
The sensitive detection of the radioactive thorium (Th) ion with an oxidation state of +4 (Th 4+ ) is of great significance for environmental protection and life safety. In this study, five fluorescence sensors with regulated donor–acceptor (D–A) interactions were constructed for Th 4+ detection based on intramolecular charge transfer and aggregation-induced emission mechanisms. Among the developed sensors, TPE-D bearing electron-deficient π-bridge and weak D–A interactions presented ratiometric fluorescence detection behavior toward Th 4+ in aqueous solution due to its aggregation-induced emission characteristics and unique D–A–D structures. Moreover, TPE-D showed excellent selectivity and sensitivity for Th 4+ detection, and the detection limit was as low as 8.1 × 10 –8 M. The sensing mechanism observation revealed that Th 4+ could coordinate with the hydroxyl, imine, and carbonyl groups of TPE-D accompanied by an electron transfer process. In addition, TPE-D could selectively be enriched in the lysosome. Both the detection of Th 4+ in the lysosome and liver of mice and zebrafish were realized based on this strategy, and a mobile-assisted detection approach toward Th 4+ in actual water samples was also established with high sensitivity. This is the first report for Th 4+ detection in organelles and organs, which provides a great significance and reliable strategy for radionuclide toxicology detection and analysis applications.