A Reversible Aggregation-Induced Emission Fluorescent Probe for Dynamic Visualization of Intracellular Mercury(II) and Cell State Differentiation

Abstract

The dynamic interplay between toxic mercury ions (Hg²⁺) and reactive sulfur species (RSS) in living systems plays a crucial role in cellular defense mechanisms and redox homeostasis. However, current fluorescent probes for Hg²⁺ are limited by their irreversibility and inability to provide the real-time information. Herein, we present a novel reversible aggregation-induced emission (AIE) fluorescent probe, NI-PSO, that overcomes these limitations. NI-PSO exhibits a remarkable 160-fold fluorescence enhancement upon Hg²⁺ binding with high sensitivity and selectivity. The probe’s unique reversibility, facilitated by the coordination interaction between phenylthioether and Hg²⁺, enables real-time monitoring of mitochondrial Hg²⁺ in the presence of exogenous and endogenous RSS. Notably, by visualizing Hg²⁺ dynamics, NI-PSO successfully differentiates various cellular states, including normal, inflammatory, and cancerous cells, providing insights into the role of RSS in mercury detoxification and maintaining cellular redox homeostasis. Our design opens up new avenues for investigating dynamic biological processes and their implications in health and disease.