Hemicyanine-based near-infrared fluorescent probe for the ultrasensitive detection of hNQO1 activity and discrimination of human cancer cells

NAD(P)H: Quinone Oxidoreductase 1 (hNQO1) is a cytosolic flavin two-electron reductase involved in many physiological and pathological processes that is overexpressed in many cancers and recognized as a potential cancer biomarker. However, it is still challenging for highly sensitive and selective monitoring hNQO1 in living cells. Here, we developed a highly selective and ultrasensitive hemicyanine-based near-infrared (NIR) fluorescence probe (probe HCYSN) for the sensing of hNQO1 activity and discrimination of human cancer cells. The fluorescent sensing system with NIR emission is low phototoxic to normal cells but is highly selective and ultrasensitive to hNQO1 in a linear range from 0.03 μg/mL to 0.6 μg/mL with detection limit (LOD) of 4.9 ng/mL (0.49 mU/mL), which is better than most of other hNQO1 probes reported. In particular, the NIR fluorescent probe was successfully applied to distinguish various cancer cells through the different distribution of endogenous hNQO1. All the present results demonstrated that the probe HCYSN exhibited great potential for human hNQO1 assay and in vivo imaging for the early cancers diagnosis and pathological studies. [Display omitted] •A new hemicyanine-based near infrared fluorescence probe HCYSN was designed.•The probe exhibited low phototoxicity to normal cells due to its NIR emission.•The probe showed high selectivity and sensitivity for detecting hNQO1 with a LOD superior to that of other probes.•The sulfonic acid group of the probe greatly promoted the interaction between probe and enzyme.•The probe was successfully applied for the visual discrimination of human cancer cells.