A Tandemly Activated Fluorescence Probe for Detecting Senescent Cells with Improved Selectivity by Targeting a Biomarker Combination.

The heterogeneous and complex phenotypes of cellular senescence necessitate a biomarker combination for the accurate detection of senescent cells from others. However, this raises the challenge of detecting multiple senescent biomarkers in the same live cell simultaneously. Herein we reported the strategy of biomarker combination triggered tandem activation for designing senescence-specific fluorogenic probes, which resulted in the development of the probe PGal-FA. The fluorescence of PGal-FA can only be activated by the sequential stimulation by the senescent biomarker combination of β-galactosidase (βGal) and formaldehyde (FA), with βGal activating the sensing ability of the probe toward FA. Facilitated by probe PGal-FA, the simultaneous detection of a biomarker combination in the same live cell was realized. We have demonstrated the improved selectivity of probe PGal-FA toward senescent cells compared to the traditional single-biomarker-based probe. Probe PGal-FA was also successfully used to detect senescent cells in bleomycin-induced pulmonary fibrosis tissues. We expect probe PGal-FA to be a reliable tool for the study on cellular senescence and envision that this probe design strategy may be expanded to other biological events to improve accuracy.