Reasonable construction of a unique near-infrared fluorescent probe with improved performance for imaging β-galactosidase in living cells and in vivo.

β- Galactosidase is closely related to primary ovarian cancer and highly expressed in metastatic ovarian cancer. Therefore, the development of effective tool for in situ detecting β -gal is urgently needed for further studies in ovarian cancer. Inspired by the advantages of near-infrared (NIR) fluorescence imaging, a NIR fluorescent probe (DCM-CHO-βgal) with improved near-infrared fluorescence emission and detection performance was reasonably designed for the quantification and visualization of β -gal, employing structurally modified dicyanobenzopyran derivative (DCM-CHO-OH) as fluorophore. DCM-CHO-βgal showed a rapid response (<20 min) towards β -gal accompanied by nearly 40-fold fluorescence enhancement at 665 nm. DCM-CHO-βgal can quantitatively detect β -gal ranging from 0.2 to 3 U/mL with a low detection limit (3.15 × 10−5 U/mL), and can selectively detect β -gal in the presence of other possible interferences. In view of excellent optical, analytical performance and good biocompatibility, DCM-CHO-βgal was applied to the visualization of endogenous β -gal in ovarian cancer cells and zebrafish, which provided a powerful tool for the in-depth study of the role of β-gal in β-gal-related diseases. [Display omitted] • A near-infrared fluorescent probe with improved performance is constructed. • The probe featured low detection limit to β -gal with high sensitivity. • The probe can visualize β -gal in living cells and zebrafish. • The probe can distinguish ovarian cancer cells from other cancer cells. [ABSTRACT FROM AUTHOR]