A mitochondria-targeting ICT probe for dual-functional peroxynitrite sensing: from live-cell imaging to serum model and plasma-activated water monitoring

Abstract

Peroxynitrite (ONOO⁻) plays dual roles as a key oxidative stress marker in pathological processes and as a critical bactericidal agent in plasma-activated water (PAW). However, real-time tracking and monitoring of ONOO⁻ within specific subcellular compartments and in complex aqueous environments remains challenging. This study presents a mitochondria-targeting fluorescent probe, TPA-Cz-PPh₃, which was engineered on an intramolecular charge transfer (ICT) platform for sensitive and selective ONOO⁻ detection. The probe exhibits a rapid response (<5 minutes), a large Stokes shift (178 nm), and a low detection limit (11 nM). Upon ONOO⁻-triggered oxidative cleavage of the CC bond, the emission shifts from 650 nm to 480 nm, enabling fluorescence-enhanced imaging in live cells. Notably, the probe successfully targeted mitochondria and achieved accurate quantification of ONOO⁻ in PAW under controlled laboratory conditions, with high recovery rates (100.06–100.18%, RSD < 1.05%), and also exhibited reliable spike recovery (98.95–101.30%) with RSD < 2.42% in fetal bovine serum (FBS). This work provides a versatile molecular tool for investigating ONOO⁻-related disease mechanisms and for monitoring disinfection efficacy in environmental applications.