A hydrazinobenzothiazole-appended phenanthroimidazole-based turn-on fluorescent probe, TPIHB, was developed for dual-channel sensing of reactive oxygen species, hypochlorite, and nerve agent simulant diethyl chlorophosphate (DCP), through two distinct mechanistic pathways in biological settings and vapor-phase applications.

Abstract

A turn-on fluorescent probe, TPIHB, featuring a hydrazinobenzothiazole-appended phenanthroimidazole core, was developed for dual-channel sensing of reactive oxygen species, hypochlorite, and nerve agent simulant diethyl chlorophosphate (DCP), through two distinct mechanistic pathways in biological settings and vapor-phase applications. The probe lighted up with a strong blue signal at 437 nm due to the formation of triazole TPITT through the hypochlorite-induced intramolecular oxidative cyclization. In contrast, DCP-triggered protonation of the secondary nitrogen led to the formation of ICT-enabled TPIHB-DH, resulting in a bright cyan emission at 458 nm in an aqueous THF medium. With excellent selectivity over other ROS and phosphates, the probe displayed a rapid response time of 30 s for hypochlorite and 14 s for DCP. Additionally, it displayed high sensitivity, with detection limits of 13.73 nM for hypochlorite and 16.96 nM for DCP. Moreover, TPIHB was employed to monitor hypochlorite in environmental water samples, in solid-state TLC strip studies, in commercial disinfectants, exogenous bioimaging in human breast cancer cells (MDA-MB 231), and endogenous bioimaging in RAW 264.7 macrophage cells with very low cytotoxicity and good cell viability. On the other hand, aiming at real-world applicability, a probe-embedded filter paper strip was fabricated, designed for real-time sensing of DCP vapor through smartphone-supported analysis, and also with cotton biopolymer as the supporting matrix.