Novel fluorescent probe for rapid and ratiometric detection of β-galactosidase and live cell imaging.

β-Galactosidase (β-gal) is an important biomarker for primary ovarian cancers and cell senescence; however, a fast response fluorescent probe for ratiometric monitoring is still rare. A novel, ratiometric water-soluble fluorescent probe (FLM) for β-gal was developed. The emission ratio F/F reached the maxima at about 5 min and can be used for real-time detection of β-gal; the ratio gained an ultimate enhancement of about 260-fold. The ratio (F/F) displayed brilliant β-gal-dependent performance and responded linearly with β-gal activity. The probe showed wonderful biocompatibility and was successfully used for the bioimaging of endogenous β-gal in the human ovarian cancer cell line OVCAR-3.