A highly responsive, sensitive NIR fluorescent probe for imaging of superoxide anion in mitochondria of oral cancer cells.

Superoxide anion (O) is an important biomarker for reactive oxygen species (ROS) generated through physiological and pathological processes. However, due to the short half-life of O and high autofluorescence of cell tissues, in situ real-time tracking and monitoring of endogenous O can be difficult. In this paper, a fluorescent probe IFP-O was developed to detect endogenous O in cells. The probe could instantaneously react with O to produce fluorescence off-on effect; its detection limit was as low as 10 nM. Cell experiments also showed that the probe had low toxicity and mitochondrial targeting ability. The article presents, for the first time, a probe that can be employed to measure endogenous O in oral cancer Cal-27 cells and is a promising tool for monitoring and evaluating apoptosis.