A mitochondrial-targetable dual functional near-infrared fluorescent probe to monitor pH and H2O2 in living cells and mice

Abstract

A lower pH level and high hydrogen peroxide (H₂O₂) concentration in mitochondria is closely associated with a variety of diseases including cancer and inflammation. Thus, determination of changes in the level of acidic pH and H₂O₂ is of great importance and could provide new insights into the key functions under both physiological and pathological conditions. Herein, we present a novel mitochondria-targetable probe NIR-pH-H₂O₂, as the first near infrared (NIR) fluorescent small molecule, to monitor changes of endogenous pH (pk_a = 6.17) and H₂O₂ with high sensitivity, good compatibility and low cytotoxicity. Futhermore, it was successfully employed to monitor pH and H₂O₂ in a mouse acute inflammation model. These results demonstrate that NIR-pH-H₂O₂ is a novel bifunctional mitochondrial-targeted NIR probe to sense acidic pH and H₂O₂ in vitro and in vivo, indicating its huge potential for the diagnosis of pH and H₂O₂-related diseases.