A unique off-on near-infrared QCy7-derived probe for selective detection and imaging of hydrogen sulfide in cells and in vivo.

Hydrogen sulfide (H2S) has been found to be an important biological regulator that plays important roles in many physiological and pathological processes. Near-infrared (NIR) fluorescent probes capable of selectively detecting H2S in vivo will be useful tools to understand its mechanisms in biological processes. Herein, we reported an easily synthesized and stimuli-responsive NIR fluorescent probe (QCy7-HS) for selective evaluation of endogenous H2S in the living cells and mice. In response to cellular H2S stimulus, QCy7-HS is converted to QCy7 and shows a unique off-on near-infrared fluorescence signal change. The results of selectivity and kinetic studies indicated that our probe has high H2S binding capacity. Therefore, this probe was used for the fluorescence detection of H2S in cells. Moreover, the probe was applied for study exogenous and endogenous H2S in live mice, indicating that the new probe can be used as an efficient tool on H2S related events in living animals.