A novel NIR fluorescent probe with fast response and large stokes shift for the detection and imaging of hypochlorous acid in living cells

Hypochlorous acid (HOCl), one of the physiologically important reactive oxygen species (ROS), is engaged in a diverse variety of biological and pathophysiological functions. Excessive HOCl buildup can cause a variety of illnesses, therefore, the identification of events in real-time of abnormal levels of exogenous and endogenous HOCl in biological settings is extremely important. In the present paper, we reported a new near-infrared emissive fluorescent probe D-HBT-HOCl for the detection and bioimaging of HOCl in live cells. With regard to the construction of D-HBT-HOCl, we combined the dicyanoisophorone motif with a 2-aminobenzenethiol unit, resulting in the near-infrared emission wavelength of 700 nm and an ultra-large Stokes shift of 180 nm, which potentially endowed D-HBT-HOCl with superiority in biological imaging. In addition, the N, N-dimethylthiocarbamate served as an efficient recognition group for HOCl as well as a fluorescence quenching group in the probe. The results of the experiments showed that the newly designed probe exhibited excellent sensing capacity, including outstanding selectivity, a high signal-to-noise ratio, and a rapid response time for the detection of HOCl. What's more, this probe was further effectively leveraged for the imaging of both extrinsic and intrinsic HOCl in live cells, demonstrating its versatility, and possessed the potential to be used to further investigate the physiological and pathological activity of HOCl in biological systems.