An Activatable and Switchable Nanoaggregate Probe for Detecting H₂ S and Its Application in Mice Brains

Employing a sequentially activated probe design method, an activatable, switchable and dual-mode probe was designed. This nanoprobe, HSDPP, could be effectively activated by H₂ S to form H-type aggregates with green emission; subsequently, the aggregates could bind to mtDNA to form monomers and the emIssion color switched from green to deep-red. We exploited HSDPP to image exogenous and endogenous H₂ S in living cells. Of note, for the first time, this novel nanoprobe with an optimal partition coefficient value (LogP=1.269) was successfully applied for tracking the endogenous H₂ S upregulation stimulated by cystathionase activator S-adenosyl-L-methionine (SAM) in mice brains. Finally, our work provides an invaluable chemical tool for probing endogenous H₂ S upregulation in vitro/vivo and, importantly, affords a prospective design strategy for developing switchable chemosensors to unveil the relationship between biomolecules and DNA in mitochondria in many promising areas.