Azacoumarin-based "turn-on" fluorescent probe for the detection and imaging of hydrogen peroxide in living cells.

Azacoumarins are a relatively unexplored group of coumarin fluorophores, despite their excellent light-emitting properties. In this report, we detail the creation and production of a fluorescent probe (PYCB) based on azacoumarin for detecting HO. The probe utilizes a carboxy benzyl boronic pinacol ester as the recognition unit and displays a turn-on fluorescence response at 460 nm upon exposure to HO. The probe shows excellent sensitivity and selectivity to HO, with a detection limit of 0.385 μM. PYCB also exhibited strong pH stability and selectivity for HO over other reactive oxygen species (ROS). Additionally, MTT assay results demonstrated the excellent biocompatibility of PYCB in MCF-7 cell lines. Fluorescence imaging of PYCB-treated MCF-7 cells revealed enhanced blue fluorescence corresponding to varying concentrations of exogenous HO.