Pyrene-based dual-mode nanoprobe for hydrogen peroxide determination and mitochondria-targeted fluorescent imaging

A novel ultra-small dual-mode pyrenyl nanoprobe (PQL-B NPs, approximately 1.47 nm) was constructed for selective detection of H₂O₂ using quaternized quinoline unit and boronate as mitochondrial targeting moiety and reactive recognition group, respectively. PQL-B NPs exhibit a distinct fluorescence shift from orange-red to bright blue after reacting with H₂O₂, accompanying a clear visible color change from yellow to colorless. In particular, this dual-mode sensing mechanism was confirmed by ¹H NMR spectra and DFT calculations. The PQL-B NPs probe encapsulated with amphiphilic DSPE-mPEG-2000 possesses good biocompatibility, superior specificity, and satisfactory sensitivity (LOD, 0.59 μM) and has been successfully used to image hydrogen peroxide in living HeLa cells with excellent mitochondrial-targeting ability.