Highly selective fluorescent and colorimetric probe for live-cell monitoring of sulphide based on bioorthogonal reaction

Activity-Based Fluorescent Probes for Hydrogen Sulfide and Related Reactive Sulfur Species

Hydrogen sulfide (H2S) is not only a well-established toxic gas but also an important small molecule bioregulator in all kingdoms of life. In contemporary biology, H2S is often classified as a "gasotransmitter," meaning that it is an endogenously produced membrane permeable gas that carries out essential cellular processes. Fluorescent probes for H2S and related reactive sulfur species (RSS) detection provide an important cornerstone for investigating the multifaceted roles of these important small molecules in complex biological systems. A now common approach to develop such tools is to develop "activity-based probes" that couple a specific H2S-mediated chemical reaction to a fluorescent output. This Review covers the different types of such probes and also highlights the chemical mechanisms by which each probe type is activated by specific RSS. Common examples include reduction of oxidized nitrogen motifs, disulfide exchange, electrophilic reactions, metal precipitation, and metal coordination. In addition, we also outline complementary activity-based probes for imaging reductant-labile and sulfane sulfur species, including persulfides and polysulfides. For probes highlighted in this Review, we focus on small molecule systems with demonstrated compatibility in cellular systems or related applications. Building from breadth of reported activity-based strategies and application, we also highlight key unmet challenges and future opportunities for advancing activity-based probes for H2S and related RSS.

A highly selective colorimetric and fluorescent probe Eu(tdl)2abp for H2S sensing: Application in live cell imaging and natural water

Using 4-([2,2': 6', 2'- terpyridin] -4'-yl) -N, N-dimethylaniline (tdl) as auxiliary ligand and 6-azido-2,2'-bipyridine (abp) as recognition ligand, a europium complex fluorescent probe Eu(4-([2,2': 6', 2'-terpyridin] -4' -yl) -N, N-dimethylaniline)₂-6-azido-2,2'-bipyridine Eu(tdl)₂abp for efficient and specific recognition of hydrogen sulfide (H₂S) was successfully synthesized and characterized by NMR and MS. Eu(tdl)₂abp represented "on-off" fluorescence signals for H₂S and its color changes could be identified with naked eyes. Eu(tdl)₂abp had short response time (2 min) to H₂S, high selectivity and good anti-interference, large stokes shift (207 nm). In various samples, when H₂S existed, the azide group was reduced to amine group, resulting in closed fluorescence signal, and the fluorescence intensity reached the degree of quenching without being affected by other interference. At the same time, there was a good linear relationship between relative fluorescence intensity and H₂S concentration with the detection limit (LOD) of 0.64 μM. The sensing mechanism of Eu(tdl)₂abp to detect H₂S was characterized by ¹H NMR and HR-MS. Eu(tdl)₂abp was used with success for the sensitive detection of H₂S in natural water and living cells.

Gut microbiota and neuroinflammation in pathogenesis of hypertension: A potential role for hydrogen sulfide

Inflammation and gut dysbiosis are hallmarks of hypertension (HTN). Hydrogen sulfide (H2S) is an important freely diffusing molecule that modulates the function of neural, cardiovascular and immune systems, and circulating levels of H2S are reduced in animals and humans with HTN. While most research to date has focused on H₂S produced endogenously by the host, H2S is also produced by the gut bacteria and may affect the host homeostasis. Here, we review an association between neuroinflammation and gut dysbiosis in HTN, with special emphasis on a potential role of H2S in this interplay.

A novel water-soluble fluorescence probe based on ICT lighten for detecting hydrogen sulfide and its application in bioimaging

Endogenous H₂S, considered to be involved in many physiological processes, has attracted more attention in fluorescence detection and bioimaging. Therefore, it is necessary to design probes with good biocompatibility and high bioavailability. In this study, a novel fluorescent probe, QN-1, based on azide group and quinoline derivatives was developed for detecting H₂S. QN-1 can detect H₂S specifically in aqueous phase, which indicated QN-1 has excellent water solubility. Besides, QN-1 shows excellent properties of higher selectivity and 11-fold fluorescence enhancement at 533 nm. Therefore, QN-1 with excellent properties can be used for cell imaging.

Superb-selective chemodosimetric signaling of sulfide in the absence and in the presence of CT-DNA and imaging in living cells by a plant alkaloid berberine analogue

New berberine analogue (BER-S), as a colorimetric probe in the absence of DNA and turn-on fluorometric probe in the presence of DNA towards S²⁻ detection is reported.

A dual-response sensor based on NBD for the highly selective determination of sulfide in living cells and zebrafish

A dual chemosensor, 1-NO₂, showing fluorogenic and colorimetric responses was developed for the detection of sulfide in vitro and in vivo.

Highly selective turn-on probe for H2S with imaging applications in vitro and in vivo

A pyrene-based chemosensor, PyN3, has been developed as a H₂S turn-on sensor via reduction of azide to amine.

Cyclodextrin-Based Metal-Organic Nanotube as Fluorescent Probe for Selective Turn-On Detection of Hydrogen Sulfide in Living Cells Based on H2S-Involved Coordination Mechanism

Hydrogen sulfide (H₂S) has been considered as the third biologically gaseous messenger (gasotransmitter) after nitric oxide (NO) and carbon monoxide (CO). Fluorescent detection of H₂S in living cells is very important to human health because it has been found that the abnormal levels of H₂S in human body can cause Alzheimer’s disease, cancers and diabetes. Herein, we develop a cyclodextrin-based metal-organic nanotube, CD-MONT-2, possessing a {Pb₁₄} metallamacrocycle for efficient detection of H₂S. CD-MONT-2′ (the guest-free form of CD-MONT-2) exhibits turn-on detection of H₂S with high selectivity and moderate sensitivity when the material was dissolved in DMSO solution. Significantly, CD-MONT-2′ can act as a fluorescent turn-on probe for highly selective detection of H₂S in living cells. The sensing mechanism in the present work is based on the coordination of H₂S as the auxochromic group to the central Pb(II) ion to enhance the fluorescence intensity, which is studied for the first time.

Selective and sensitive detection of hydrogen sulfide in live cells

We report herein a fluorescence switch-on probe suitable for the detection of hydrogen sulfide (H₂S) in complex biological systems.

Silicon nanowires-based fluorescent sensor for in situ detection of hydrogen sulfide in extracellular environment

Based on a Si nanowire array, a fluorescent sensor for H₂S was realized and successfully used for real time and in situ imaging of the changes in extracellular H₂S of live cells.