https://repository.kulib.kyoto-u.ac.jp -2-K.M. and N.I. conceived and designed the research; N.I. and K.N. executed the synthetic experiments; K.M., N.I., K.N., M.O., H.M., W.H., and H.H. executed the biological experiments; K.O. directed the project and wrote the paper with K.M.

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 gal-BP-PMB (-galactosyl-3,3-dihydroxy-2,2-bipyridyl-p-methoxybenzyl), the photoluminescence of which can be activated by -galactosidase (-gal) and acidic conditions. The overexpression of -gal is an important feature of senescent and ovarian cancer cells. Single-input activatable probes for detecting -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 gal-BP-PMB can be specifically activated in ovarian cancer cells, but silenced in senescent cells. Probe gal-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.

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