Hydrogen sulfide (H2S) is an important gasotransmitter. Although a large number of fluorescent probes for cellular H2S have been reported, only a few can detect H2S in mitochondria, a cellular organelle connecting H2S with mitochondrial function and metabolic pathways. We hereby describe a novel near-infrared fluorescent probe, nimazide, by introducing sulfonyl azide to the core structure of a QSY-21 dark quencher. Nimazide responded quickly to H2S, resulting in robust fluorescence turn-off changes. This conversion displayed high specificity and fast kinetics. More impressively, we observed a robust fluorescence decrease in live cells loaded with mitochondrial nimazide in response to extracellular addition of nanomolar H2S, and successfully imaged biologically generated mitochondrial H2S in live mammalian cells. Nimazide is one of the most sensitive fluorescent probes for mitochondrial H2S.

中文翻译：

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用于线粒体硫化氢的灵敏的近红外荧光传感器。

硫化氢（H2S）是重要的气体传输剂。尽管已报道了大量用于细胞H2S的荧光探针，但只有少数能检测到线粒体中的H2S，线粒体是连接H2S与线粒体功能和代谢途径的细胞器。我们在此描述一种新型的近红外荧光探针，尼马西德，是通过将磺酰叠氮化物引入QSY-21暗猝灭剂的核心结构而实现的。Nimazide对H2S的反应很快，从而导致强大的荧光关闭变化。该转化显示出高特异性和快速动力学。更加令人印象深刻的是，我们观察到响应纳摩尔H2S的细胞外添加，在装载了线粒体氮化物的活细胞中荧光显着降低，并成功地在哺乳动物活体细胞中对生物学产生的线粒体H2S进行了成像。