Mitochondria Targeting Fluorescent Probes Based on through Bond-Energy Transfer for Mutually Imaging Signaling Molecules H2 S and H2 O2.

Reactive signaling molecules participate in varieties of biochemical reactions, and methods to detect their mutual existence and crosstalk are in urgent demand. A benzothiadiazole-based handle was designed to fluorescently respond to the co-existence of H2 S and H2 O2 under pseudo-physiological conditions on a basis of a thiyl-radical-mediated mechanism that accounts for the rapid and efficient domino-like reaction processes. Then the handle motif was attached to a rhodamine moiety by means of an ethynylene linkage, and achieved a significant H2 S-H2 O2 mutual response in the mitochondria of living cells. Theoretical calculations supported that a through bond energy transfer mechanism contributes to the drastic fluorescence response.