An HPQ-based near-infrared dye for the detection of ClO− and accurate imaging of cells and mouse tumor sites in situ

Abstract

A new fluorescent probe (SWJT-32) with a large Stokes shift was designed and synthesized with 2-(2-hydroxyphenyl)-4(1H)-quinazolinone (HPQ) as the skeleton and N,N-dimethylthiocarbamate as the recognition site. It can detect hypochlorite ions (ClO⁻) through fluorescence spectroscopy based on the excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) mechanism. The probe has the advantages of strong diffusion resistance, good photostability and selectivity, and high imaging contrast, and can be used for the detection of ClO⁻. Meanwhile, due to its low toxicity and good biocompatibility in living cells, SWJT-32 can be used for the detection of endogenous and exogenous ClO⁻ in HeLa cells as well as for long-term in vivo imaging in tumor mice.