Design of a facile fluorescent probe with a large Stokes shift for hydrogen peroxide imaging in vitro and in vivo

By modifying 4'‑hydroxybiphenyl‑4‑carbonitrile (BPN-OH) with 2‑(4‑(bromo‑methyl)phenyl)‑4,4,5,5‑tetramethyl‑1,3,2‑dioxaborolane group, a facile fluorescent probe, BPN-TOB, for sensitively tracing H₂O₂ was designed and synthesized. BPN-TOB displayed a low detection limit (67 nM), fast response time (10 min), low cytotoxicity, a mega Stokes shift (170 nm) and a remarkable fluorescence enhancement (72-fold) in the detection of H₂O₂. Additionally, probe BPN-TOB could monitor exogenous and endogenous H₂O₂ in living MGC-803 cells (human gastric cancer cells) and RAW264.7 cells (leukemia cellsin mouse macrophage). In particular, this probe BPN-TOB was successfully utilized for imaging H₂O₂ in zebrafish.