A perylene diimide-based fluorescent probe for the selective detection of hypochlorite in living cells

Abstract

Electron leakage in the respiratory chain of mitochondria is the major causative factor for the production of reactive oxygen species (ROS), including hypochlorite (OCl⁻). As one of the most important ROS, OCl⁻ plays a vital role in the innate host defense and regulation of inflammation-related pathological conditions. Herein, a perylene diimide-based fluorescent probe (PDI-S) for OCl⁻ detection in mitochondria was developed, which utilized the CS bond of imidazole thiones as an OCl⁻ reactive moiety. When PDI-S was reacted with OCl⁻ to form an oxidized cationic diimidazolium salt, a significant enhancement in fluorescence intensity was observed under 564 nm. Cellular imaging revealed that PDI-S could sense both the exogenous OCl⁻ in A549 cells and endogenous OCl⁻ in RAW 264.7 macrophages with high selectivity and ultra-fast response with high specificity for mitochondria. The molecular design represents an attractive paradigm to guide the layout of fluorescent probes for further development of fluorescence detection.