Novel naphthalimide derived fluorescent probe based on aggregation-induced emission for turn-on detection of hydrogen sulfide

Novel thiomaleimide-based fluorescent probe with aggregation-induced emission for detecting H2S

It has been well established that Hydrogen sulfide (H2S) is involved in various pathophysiological processes. Therefore, accurate monitoring H2S levels in vitro or vivo is of great significance in biological systems. Herein, we firstly developed a thiomaleimide-based compound MAL-1 bearing aggregation-induced emission characteristic for selective response toward H2S due to its nucleophilicity. The proposed sensor presented prominent sensitivity and selectivity with low detection limit of 75 nM and pseudo-first-order reaction rate constant of 9.65 × 10-2 s-1, as well as low cytotoxicity which works well in recognizing H2S in real samples and visualizing H2S in living cells. Thus, it could be concluded that the novel thiomaleimide-based probe would be a promising tool for assessing intracellular H2S levels.

Difunctional Fluorescent Probes for Iron and Hydrogen Sulfide Detection Based on Diphenyl Derivative

In order to better monitor the content of Fe3+ and H2S in the biological environment, two new fluorescent probes were designed and synthesized. With the addition of Fe3+, the strong fluorescence emission of two probes was significantly quenched due to the paramagnetic effect of Fe3+. With the further addition of S2-, the fluorescence intensity was quickly restored. Two probes showed high selectivity and strong sensitivity for the detection of Fe3+ and S2-, and the fluorescence intensity "ON-OFF-ON" was accompanied with the interaction process. At the same time, two probes displayed good anti-interference ability which was not interfered by the existence of other ions. In addition, two probes illustrated fast response time to Fe3+, S2- and small cytotoxicity to cells. Therefore, two probes can provide a potential ideal tool for detecting Fe3+ and H2S in organisms and the environment.

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 Novel DNBS-based Fluorescent Probe for the Detection of H2S in Cells and on Test Strips

Hydrogen sulfide (H2S) plays a key role in the physiology and pathology of organisms, and H2S in the environment is easily absorbed and harmful to health. It is of great significance to develop a probe with good selectivity, high sensitivity and good stability that can detect hydrogen sulfide inside and outside organisms. In this work, we designed a novel "turn-on" fluorescent probe CIM-SDB for the detection of H2S. The probe CIM-SDB used indene-carbazole as the fluorophore and 2,4-dinitrobenzenesulfonyl as the recognition site. The probe CIM-SDB exhibited high selectivity and sensitivity to H2S (detection limit as low as 123 nM). Moreover, the probe CIM-SDB was successfully applied to the detection of intracellular exogenous and endogenous H2S, and the test strips prepared by the probe CIM-SDB could realize the convenient and rapid detection of H2S.

Synthesis and applications of a corrole-based dual-responsive fluorescent probe for separate detection of hydrazine and hydrogen sulfide

Here, a corrole-based dual-responsive fluorescent probe DPC-DNBS was rationally designed and synthesized for the separate detection of hydrazine (N₂H₄) and hydrogen sulfide (H₂S) with high selectivity and sensitivity. The probe DPC-DNBS is intrinsically none fluorescent due to PET effect, however, addition of increasing amount of N₂H₄ or H₂S to DPC-DNBS turned on an excellent NIR fluorescence centered at 652 nm and thereby provided a colorimetric signaling behavior. The sensing mechanism was verified by HRMS, ¹H NMR and the DFT calculations. Common metal ions and anions do not interfere with the interactions of DPC-DNBS with N₂H₄ or H₂S. Furthermore, the presence of N₂H₄ does not affect the detection of H₂S; however, the presence of H₂S interferes with the detection of N₂H₄. Hence, quantitative detection of N₂H₄ must occur in an H₂S-free environment. The probe DPC-DNBS displayed some fascinating merits in separate detection of these two analytes, including large Stokes shift (233 nm), fast response (15 min for N₂H₄, 30 s for H₂S), low detection limit (90 nM for N₂H₄, 38 nM for H₂S), wide pH range (6-12) and outstanding biological compatibility. Significantly, DPC-DNBS was utilized to detect hydrazine in real water, soil and food samples. And its favorable performances for separate detection N₂H₄ and H₂S were successfully demonstrated in HeLa cells and zebrafish, indicating its value of practical application in biology.

Mitochondria-targeted fluorescent probe with long wavelength emission for detecting H2S and its application in foodstuff, water and living cells

Hydrogen sulfide (H₂S) is crucial to cellular energy production, apoptosis, and redox homeostasis in mitochondria of living cells. In this work, a unique mitochondria-targeting fluorescence probe (DDMI) was established for H₂S determination based on styrylpyridinium scaffold. When DDMI was treated with H₂S, it showed significant fluorescence enhancement at 623 nm, with good selectivity, and high sensitivity. In addition, the "turn-on" fluorescent probe DDMI could detect H₂S in water samples with good recoveries in the range of 95.4 %-105.6 % and track the degree of food spoilage by visualizing the change of DDMI-loaded test strips. Furthermore, the established probe DDMI was successfully used for monitoring exogenous H₂S in living cells and mitochondria targeting. These results paved the way for success in developing a technology that could be used to identify H₂S in environment, foodstuff, and living cells.

Using Room Temperature Phosphorescence of Gold(I) Complexes for PAHs Sensing

The synthesis of two new phosphane-gold(I)–napthalimide complexes has been performed and characterized. The compounds present luminescent properties with denoted room temperature phosphorescence (RTP) induced by the proximity of the gold(I) heavy atom that favors intersystem crossing and triplet state population. The emissive properties of the compounds together with the planarity of their chromophore were used to investigate their potential as hosts in the molecular recognition of different polycyclic aromatic hydrocarbons (PAHs). Naphthalene, anthracene, phenanthrene, and pyrene were chosen to evaluate how the size and electronic properties can affect the host:guest interactions. Stronger affinity has been detected through emission titrations for the PAHs with extended aromaticity (anthracene and pyrene) and the results have been supported by DFT calculation studies.

A novel fast-responsive fluorescent probe based on 1,3,5-triazine for endogenous H2S detection with large Stokes shift and its application in cell imaging

A novel fast-responsive fluorescent probe TzAr-H2S based on 1,3,5-triazine was constructed to monitor endogenous H₂S. The probe TzAr-H2S can quickly (only 20 s) detect H₂S with good selectivity, large Stokes shift (100 nm) and low cytotoxicity.