Dual-Stimuli-Responsive Probes for Detection of Ovarian Cancer Cells and Quantification of Both pH and Enzyme Activity

Many physiological processes involve multiple coordinated chemical and/or biological events. Therefore, it is considered urgent to develop dual-responsive probes for a more comprehensive understanding of the synergistic effects between multiple analytes in complex cellular environments. In this study, we developed a dual-responsive probe βgal-BP-PMB (β-galactosyl–3,3′-dihydroxy-2,2′-bipyridyl–p-methoxybenzyl), the photoluminescence of which can be activated by β-galactosidase (β-gal) and acidic conditions. The overexpression of β-gal is an important feature of senescent and ovarian cancer cells. Single-input activatable probes for detecting β-gal activity in ovarian cancer cells can induce a false positive response from senescent cells. Because the lysosomal pH in senescent cells is increased, probe βgal-BP-PMB can be specifically activated in ovarian cancer cells, but silenced in senescent cells. Probe βgal-BP-PMB has a small molecular size, high sensitivity towards targeted stimuli and unique ratiometric properties, thereby enabling the quantification of both pH and enzyme activity. Such dual-responsive probes could earn a unique place in the field of bioimaging, where multiple analytes should be accurately and simultaneously monitored. Dual-responsive ratiometric probes enabling the detection of ovarian cancer cells without false positive response from senescent cells and the simultaneous quantification of pH and enzyme activity in an unknown sample have been developed.