PEGylated near-infrared fluorescence probe for mitochondria-targetable hydrogen peroxide detection

Oxidative stress plays significant roles in the development of various diseases. H₂O₂ acts as a signaling molecule physiologically or harmful substance pathologically and the mitochondria are one of the most active places for the generation of H₂O₂. Thus, a new mitochondria-targeted probe 1 for H₂O₂ detection was synthesized herein, based on D-π-A structure with a large Stokes shift (150 nm) due to its ICT process. To improve its water solubility and sensitivity, probe 2 with PEG chain and probe 3 with two responsive boronated groups were then designed based on the structure of probe 1. As a result, the fluorescence intensity of probe 2 was far higher than that of probe 1 and probe 3 not only in vitro experiment but in cell imaging study with a larger linear range and signal-to-noise ratio, rendering it the best probe for further exogenous and endogenous H₂O₂ detection in Hela cells.