A Sensitive Near-Infrared Fluorescent Sensor for Mitochondrial Hydrogen Sulfide

Abstract

Hydrogen sulfide (HS) is an important gasotransmitter. Although a large number of fluorescent probes for cellular HS have been reported, only a few can detect HS in mitochondria, a cellular organelle connecting HS 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 HS, 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 HS, and successfully imaged biologically generated mitochondrial HS in live mammalian cells. Nimazide is one of the most sensitive fluorescent probes for mitochondrial HS.

A Powerful Turn‐On Fluorescent Probe for Phosgene: A Primary Amide Strategically Attached to an Anthracene Fluorophore

“…However, the linear nature of the nitrile functionality in the product, 9‐ACN makes the molecule amenable to radiative emission and this is the basis for successful application of 9‐AM in phosgene sensing . Emission enhancement at still higher wavelengths, notably those approaching the Near InfraRed (NIR) zone of the electromagnetic spectrum, are certainly desirable for many modern sensing purposes due to the superior biological advantages associated . However, when it comes to lethal substances such as the nerve agent precursor, phosgene, sensing and containment before these make their way into living organisms is of supreme importance.…”

Emerging analytical tools for the detection of the third gasotransmitter H2S, a comprehensive review

“…: near infrared emission (710 nm), detection medium aqueous (PBS) Disadv. : long response time (40 min); small Stokes shift (60 nm), Application: mitochrondria / human embryonic kidney (HEK) 293 T & HeLa cells [52] F7 Adv. : good hepatocyte-targeting, excellent water solubility, low cytotoxicity, fast response (within 1 min), high selectivity, good sensitivity (LOD 126 nM) Application: hepatocyte-targeting [51] F8 Adv.…”

“…Many sensors were developed exhibiting “turn-off” fluorescence response, Table 1 . for example compound F9 contains an azide group linked to rhodamine derivative as a fluorophore [52] . This compound was used for quantifying H 2 S in human embryonic kidney 293 T cells and could target mitochondria but it suffers from relatively long response time (40 min).…”

Near-Infrared Mitochondria-Targetable Fluorescent Probe for High-Contrast Bioimaging of H2S

“…In this respect, fluorescence probes exhibited great potential due to their advantages of excellent sensitivity, simple operation, and noninvasive in situ and real-time spatial imaging. − Over the past decade, the development of fluorescent probes for H 2 S has attracted extensive attention and a huge amount of probes have been developed for the fluorescence detection of H 2 S. − Although great success has been achieved, most of them are incompetent in visualizing H 2 S in mitochondria and in vivo, mainly due to their short fluorescence wavelengths (<650 nm) and lack of mitochondrial localization performance. Currently, only a few probes are available to detect H 2 S in mitochondria. − However, they are mainly fluorescent probes with visible fluorescence changes, and many of them suffer from long response time, narrow Stokes shifts, and/or unsatisfactory water solubility (Table S1). For in vivo detection and imaging, probes with near-infrared (NIR) fluorescence have been proved to be more suitable; however, NIR probes for H 2 S detection in mitochondria and in vivo are very rare. − To date, only a few NIR H 2 S probes have been shown to have mitochondrial-targeting properties, and still, they showed drawbacks of “turn-off” NIR fluorescence and small Stokes shifts, , poor water solubility and long reaction time, or applicability only in living cells .…”