A probe with double acetoxyl moieties for hydrazine and its application in living cells

A dual-color ESIPT-based probe for simultaneous detection of hydrogen sulfide and hydrazine

Hydrogen sulfide (H2S) and hydrazine (N2H4) are toxic compounds in environmental and living systems, and hydrogen sulfide is also an important signaling molecule. However, in the absence of dual-color probes capable of detecting both H2S and N2H4, the ability to monitor the crosstalk of these substances is restricted. Herein, we developed an ESIPT-based dual-response fluorescent probe (BDM-DNP) for H2S and N2H4 detection via dually responsive sites. The BDM-DNP possessed absorbing strength in the detection of H2S and N2H4, with a large Stokes shift (156 nm for H2S and 108 nm for N2H4), high selectivity and sensitivity, and good biocompatibility. Furthermore, BDM-DNP can be utilized for the detection of hydrogen sulfide and hydrazine in actual soil, and gaseous H2S and N2H4 in environmental systems. Notably, BDM-DNP can detect H2S and N2H4 in living cells for disease diagnosis and treatment evaluation.

Engineering a "turn-on" NIR fluorescent sensor-based hydroxyphenyl benzothiazole with a cinnamoyl unit for hydrazine and its environmental and in-vitro applications

Hydrazine (N2H4), a chemical compound widely used in various industrial applications, causes significant environmental and biological hazards. Therefore, it is crucial to develop methodologies for the visualization and real time tracking of N2H4. In this regard, we have constructed a novel near-infrared fluorescent probe (HBT-Cy) that can effectively detect N2H4 in various samples. HBT-Cy contains 2-(2'-hydroxyphenyl)benzothiazole (HBT), cinnamoyl (Cy), and pyridinium (Py) moieties. Importantly, HBT-Cy exhibits a rapid, selective, and highly sensitive response to N2H4. This response results in the release of HBT-Py and the generation of considerable colorimetric changes along with a significant NIR (near infrared) fluorescence signal, peaking at 685 nm. Advantages of this system include turn on NIR fluorescence with large Stokes shift, (approximately 171 nm), low limit of detection (LOD = 0.11 μM) and quantum yield (0.211). The probe with low cytotoxic behavior demonstrates strong NIR fluorescence imaging capabilities to visualize endogenous and exogenous N2H4 in live cells. This mitochondria-targetable probe shows effective subcellular localization. These results suggest that HBT-Cy is a valuable probe for tracking and investigating the behavior of N2H4 in biological systems and environmental samples.

A Ratiometric Fluorescent Probe for N2H4 Having a Large Detection Range Based upon Coumarin with Multiple Applications

Although hydrazine (N2H4) is a versatile chemical used in many applications, it is toxic, and its leakage may pose a threat to both human health and environments. Consequently, the monitoring of N2H4 is significant. This study reports a one-step synthesis for coumarin-based ratiometric fluorescent probe (FP) CHAC, with acetyl as the recognition group. Selected deprotection of the acetyl group via N2H4 released the coumarin fluorophore, which recovered the intramolecular charge transfer process, which caused a prominent fluorescent, ratiometric response. CHAC demonstrated the advantages of high selectivity, a strong capacity for anti-interference, a low limit of detection (LOD) (0.16 μM), a large linear detection range (0-500 μM), and a wide effective pH interval (6-12) in N2H4 detection. Furthermore, the probe enabled quantitative N2H4 verifications in environmental water specimens in addition to qualitative detection of N2H4 in various soils and of gaseous N2H4. Finally, the probe ratiometrically monitored N2H4 in living cells having low cytotoxicity.

Advances in Optical Probes for the Detection of Hydrazine in Environmental and Biological Systems

Hydrazine, as a crucial raw material in the fine chemical industry, plays an indispensable role in fuel, catalyst, pesticide and drug synthesis. Due to its good water solubility and high toxicity, hydrazine can cause irreparable damage to water and soil in the environment, and it can also be released by taking certain drugs, which brings potential risks to human health. Therefore, it is vital to develop a method that can specifically detect hydrazine in the environment and in vivo. As an effective analysis and detection tool, fluorescence probe has attracted extensive attention in recent years. In this review, we summarized and classified hydrazine fluorescence probes based on various reaction mechanisms, and discussed their structures and applications in the past ten years. At least, we briefly outline the challenges and prospects in this field.

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.

A flavonol-derived fluorescent probe for highly specific and sensitive detection of hydrazine in actual environmental samples and living zebrafish

Hydrazine (N₂H₄) is a significant chemical reagent and widely applied in industrial field, which can bring potential risk to environmental safety and human health due to its high toxicity and potential carcinogenicity. In this paper, a flavonol-derived fluorescent probe named TB-N₂H₄ was rationally developed for detecting N₂H₄ based on the excited intramolecular proton transfer (ESIPT) principle. TB-N₂H₄ exhibited a remarkable fluorescence turn-on response toward N₂H₄ with a large Stokes shift of 191 nm. Moreover, TB-N₂H₄ could selectively recognize N₂H₄ over other competitive analytes, and displayed high sensitivity toward N₂H₄ with a low detection limit of 0.117 μM. The sensing mechanism of the probe TB-N₂H₄ for N₂H₄ was confirmed by theoretical calculation and HRMS analysis. This probe was able to quantitatively determine N₂H₄ in environmental water and soil samples. Additionally, TB-N₂H₄ was also successfully utilized for real-time tracking of the distribution of N₂H₄ in living zebrafish.

A ratiometric fluorescent probe with large Stokes shift and emission shift for sensing hydrazine in living organisms

As a highly toxic reagent, hydrazine (N₂H₄) is notorious to human beings and the environment. To simply and conveniently detect N₂H₄ in environmental and biological systems, a ratiometric fluorescent probe MA-N₂H₄ was developed with excellent sensitivity and selectivity. Probe MA-N₂H₄ was readily prepared based on a naphthalene as the fluorescent scaffold and an indanedione group as the responsive moiety for N₂H₄. This probe displayed a red-emitting fluorescence at 670 nm with a large Stokes shift (200 nm). After treatment with N₂H₄, a significant blue-shifted emission at 440 nm could be observerd, which led to an extremely large emission wavelength shift (230 nm). The fluorescent intensity ratio (I₄₄₀/I₆₇₀) of probe MA-N₂H₄ was rapidly and significantly increased (273-fold) within 18 min. The detection limit for N₂H₄ was 0.5 µM. In addition, the probe was successfully employed for tracking N₂H₄ in living cells and zebrafish through a ratiometric manner.

A highly-sensitive "turn on" probe based on coumarin β-diketone for hydrazine detection in PBS and living cells

Herein, a new "turn on" fluorescent probe C-1 is developed to specifically detect hydrazine using coumarin nucleus as the fluorophore and β-diketone as the recognition group. The probe shows high selectivity towards hydrazine over other common ions and amine-containing species, as well as good water solubility and quantitative detectability of hydrazine in concentration range of 1-200 μM. The detection limit is as low as 1.89 ppb, which is lower than the threshold set by EPA (10 ppb). Probe-coated filter papers are confirmed to detect gaseous hydrazine successfully through obvious fluorescence color changes. In addition, the probe has been verified to detect hydrazine in actual water environment and living cells.

Radical anion formation exhibiting "turn-on" fluorescence sensing of hydrazine using a naphthalene diimide (NDI) derivative with a donor-acceptor-donor (D-A-D) molecular structure

In this paper, the synthesis of a naphthalene diimide (NDI) derivative with a donor-acceptor-donor (D-A-D) molecular structure substituted with a long alkyl chain (12 carbons) containing naphthalene hydrazide at the imide position is reported. The reduced emission quantum yield (φf = 0.01-0.03) of the NDI derivative in various solvents indicates the perturbation of the electronic state of π-electron deficient NDI (A) by the peripheral naphthalene (D) units. The investigation of the influence of the alkyl chain and naphthalene substituent on the self-assembling properties of the NDI derivative reveals an isodesmic mode of self-assembly in a chloroform/methylcyclohexane (CHCl3/MCH, 1 : 9, v/v) mixture. The self-assembling nature of the NDI derivative also results in the formation of an organogel in the CHCl3/MCH (1 : 9, v/v) mixture, and gel formation is well-comprehended by techniques such as P-XRD, rheological studies, and FT-IR measurements. Furthermore, radical anion (NDI˙-) formation of π-acidic NDI was used as a sensing tool for hydrazine by a fluorescence "turn-on" (φf = 0.12) method in the solution (DMSO), film, and gel state with a detection limit of 284.1 ppb in DMSO and 32 ppb in the gel state.

A new "turn-on" fluorescence probe based on hydrazine-triggered tandem reaction

Hydrazine is extremely harmful to the human body. The leakage of hydrazine is liable to cause potential safety hazards. Here, we reported a new fluorescence probe based on the tandem reaction. The hydrazine-triggered hydrazinolysis-cyclization resulted in the formation of the iminocoumarin. The fluorescence intensity at 522 nm of the probe increased after the reaction with hydrazine. There was a linear relationship between the fluorescence intensity and the concentration of hydrazine (0.14-120.00 μM). The LOD of the probe to N₂H₄ was 1.36 ppb. Notably, the probe could detect hydrazine in BT474 cells and tap water.

A New Fluorescent Turn-on Dual Interaction Position Probe for Determination of Hydrazine

Hydrazine is an important catalyst and chemical raw material. But it is highly toxic and potentially carcinogenic. We designed a new hydrazine probe based on a synergistic effect by introducing acetate and phthalimide into 2-phenyl-benzimidazole (PBI). Comparative experiments proved that "the dual position interaction" had a "synergistic effect" on fluorescence enhancement. The fluorescence enhancement caused by the probe (15.0 fold) is much larger than the sum of the fluorescence enhancement of the two monomer compounds (2.6 and 1.4 folds, respectively). A theoretical calculation showed an inhibition of the PET process and a recovery of the ICT process led to a fluorescence enhancement. The probe was specific to hydrazine and showed a linear response to it in the concentrations range of 0.2 - 200 μM with a LOD of 0.062 μM (1.99 ppb). Moreover, the probe could detect hydrazine in tap water; the recovery of hydrazine from the tap water was between 98.86 - 103.28%.

A near-infrared xanthene-based fluorescent probe for selective detection of hydrazine and its application in living cells

Developing fluorescent probes for selective determination of the toxic and carcinogenic hydrazine are pretty significant. Herein, a rhodamine dye coupled to naphthalene was selected as a near-infrared fluorophore and acetyl group as a trigger unit for hydrazine sensing with a Stokes shifts of 62 nm. The probe showed about 77-fold NIR fluorescence enhancement in the presence of hydrazine. In addition, the detection limit was as low as 3.4 ppb, and the fluorescence intensity at 654 nm showed a satisfactory linearity with the concentration range of hydrazine from 0 to 120 μM. More importantly, the practical utility of probe has been successfully proved through the fluorescence bioimaging of hydrazine in living cells with low cytotoxicity and quantitative N₂H₄ detection in environmental water samples.

A coumarin-based fluorescent probe for ratiometric detection of hydrazine and its application in living cells

A new ratiometric fluorescent probe (1) was developed for the detection of hydrazine. The probe was obtained by incorporating the recognition moiety of acetyl group onto a coumarin fluorophore. Probe 1 displayed a distinct cyan emission in a 100% aqueous phosphate buffer solution. In the presence of hydrazine, probe 1 undergoes a hydrazinolysis process to release the coumarin fluorophore, which exhibited significant hypsochromic shifts in both absorption and emission spectra, and thus achieving a ratiometric response. This ratiometric probe is highly selective and sensitive towards hydrazine detection. The limit of detection (LOD) was calculated to be 34 nM. Moreover, cellular toxicity and imaging experiments suggested that probe 1 is can be used to monitor hydrazine in live cells.

A coumarin chalcone ratiometric fluorescent probe for hydrazine based on deprotection, addition and subsequent cyclization mechanism

A coumarin chalcone derivative with a levulinic acid terminal group acts as a ratiometric fluorescent probe for hydrazine based on deprotection, addition and a subsequent cyclization reaction mechanism.