A novel activation-triggered-immobilizing fluorescent probe for real-time tracking of mitochondrial ONOOˉ with high fidelity

Peroxynitrite (ONOOˉ) can participate in signal transduction, immune response and other processes in organisms. It has been shown to be associated with multifarious diseases and metabolic disorders. The mitochondrial respiratory chain is the main site for endogenous ONOOˉ production and response. Thus, monitoring ONOOˉ dynamics in mitochondria is crucial for understanding its physiological and pathological roles. Herein, we designed and synthesized a mitochondria-immobilizing fluorescent probe CB-IMP employing an activation-triggered-immobilizing strategy. CB-IMP consists of a coumarin modified with an arylboronic ester as a recognition receptor, and a quaternized thiomorpholine salt with positive charge for mitochondria targeting and immobilization. CB-IMP with superior water solubility exhibits rapid response (t ˂ 5 s), outstanding selectivity and highly sensitive recognition towards ONOOˉ (LOD = 9 nM). Notably, the activation-triggered-immobilizing strategy provides CB-IMP with in situ tracking ability for mitochondrial ONOOˉ (P = 0.9513). Therefore, combined the low cytotoxicity and high membrane permeability, CB-IMP is allowed for highly sensitive detection and high-fidelity imaging of endogenous/exogenous mitochondrial ONOOˉ in live cells and zebrafish. It has the potential to provide new insights for the detection of mitochondrial dysfunction and early imaging and diagnosis of various related diseases.