A dual-analytes responsive fluorescent probe for discriminative detection of ClO- and N2H4 in living cells

Sulfur-based fluorescent probes for biological analysis: A review

The widespread adoption of small-molecule fluorescence detection methodologies in scientific research and industrial contexts can be ascribed to their inherent merits, including elevated sensitivity, exceptional selectivity, real-time detection capabilities, and non-destructive characteristics. In recent years, there has been a growing focus on small-molecule fluorescent probes engineered with sulfur elements, aiming to detect a diverse array of biologically active species. This review presents a comprehensive survey of sulfur-based fluorescent probes published from 2017 to 2023. The diverse repertoire of recognition sites, including but not limited to N, N-dimethylthiocarbamyl, disulfides, thioether, sulfonyls and sulfoxides, thiourea, thioester, thioacetal and thioketal, sulfhydryl, phenothiazine, thioamide, and others, inherent in these sulfur-based probes markedly amplifies their capacity for detecting a broad spectrum of analytes, such as metal ions, reactive oxygen species, reactive sulfur species, reactive nitrogen species, proteins, and beyond. Owing to the individual disparities in the molecular structures of the probes, analogous recognition units may be employed to discern diverse substrates. Subsequent to this classification, the review provides a concise summary and introduction to the design and biological applications of these probe molecules. Lastly, drawing upon a synthesis of published works, the review engages in a discussion regarding the merits and drawbacks of these fluorescent probes, offering guidance for future endeavors.

A dual-channel ICT fluorescent probe assisted by smartphone for quantitative detection, and visualization of residual hydrazine in the living cells, water, soil, plant, and food samples

BACKGROUND

Hydrazine (N2H4) serves as a crucial industrial raw material and finds extensive applications in the fields of medicine, pesticides, ecological environment, and textile dyes. Excessive residue of hydrazine will cause significant toxicity risks to the ecosystem and human health. Traditional detection methods often require multi-step pretreatment of samples, and complex instrumentation, and are time-consuming, which is not conducive to rapid on-site detection. Therefore, it is imperative to develop a method suitable for rapid detection of N2H4 in multiple fields.

RESULTS

In this study, we constructed a red emission fluorescent probe (BCM). BCM can recognize N2H4 by colorimetric and fluorescence dual-channel response with a good anti-interference ability and a low detection limitation. The fluorescence emission of BCM is attributed to the ICT effect by DFT calculations, and a new product 3H-benzo[f]chromene-2-carbaldehyde hydrazine is formed after BCM recognition of N2H4. A linear relationship was established between the ratio of red-blue (R/B) coming from the fluorescence color of BCM and the N2H4 level. Hence, a BCM-based smartphone sensing platform for detecting N2H4 was developed, and the N2H4 content can be rapidly detected with satisfactory accuracy in the lake water samples. In addition, the residues of N2H4 in soils, plants and food samples can be visualized, and BCM can image for N2H4 in living cells, as well as N2H4 vapor can be detected by using the electrospinning film loaded with BCM.

SIGNIFICANCE

In particular, the fluorescent probe BCM can be combined with a smartphone for the detection and visual imaging of hydrazine in environmental samples. We believe the BCM and smartphone-based sensing platforms constructed in this paper will be a powerful tool for visual quantitative detection of N2H4 in the fields of food safety assessment, bioimaging, and environmental protection.

Ex Tenebris Lux: Illuminating Reactive Oxygen and Nitrogen Species with Small Molecule Probes

Reactive oxygen and nitrogen species are small reactive molecules derived from elements in the air─oxygen and nitrogen. They are produced in biological systems to mediate fundamental aspects of cellular signaling but must be very tightly balanced to prevent indiscriminate damage to biological molecules. Small molecule probes can transmute the specific nature of each reactive oxygen and nitrogen species into an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging in living cells and whole animals. This review focuses specifically on small molecule probes for superoxide, hydrogen peroxide, hypochlorite, nitric oxide, and peroxynitrite that provide a luminescent or photoacoustic signal. Important background information on general photophysical phenomena, common probe designs, mechanisms, and imaging modalities will be provided, and then, probes for each analyte will be thoroughly evaluated. A discussion of the successes of the field will be presented, followed by recommendations for improvement and a future outlook of emerging trends. Our objectives are to provide an informative, useful, and thorough field guide to small molecule probes for reactive oxygen and nitrogen species as well as important context to compare the ecosystem of chemistries and molecular scaffolds that has manifested within the field.

Synthesis and Application of Specific N2H4 Fluorescent Probes with AIE Effect Based on Pyrazole Structure

Two fluorescent probes, Y1-2 were synthesized from 2-acetonaphthone, 4-acetylbiphenyl, and phenyl hydrazine by Vilsmeier-Haack reaction and Knoevenagel condensation. Their recognition efficacies for N2H4 were tested by UV-visible absorption spectroscopy and fluorescence emission spectroscopy. The recognition mechanism were studies by density-functional theory calculations, and the effect of pH on N2H4 recognition was also studied. The results showed that the probe Y1-2 has high selectivity and a low detection limit for N2H4, and the recognition of N2H4 can be accomplished at physiological pH. The probes have had obvious aggregation-induced luminescence effect, large Stokes shift, high sensitivity, and can be successfully applied to live cell imaging.

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.

Two novel fluorescent probes based on quinolinone for continuous recognition of Al3+ and ClO. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023;300:122917. [PMID: 37269662 DOI: 10.1016/j.saa.2023.122917]

On the basis of classical Schiff base reaction, two novel and efficient fluorescent probes (DQNS, DQNS1) were designed and synthesized by introducing Schiff base structure into dis-quinolinone unit for structural modification, which can be used to detect Al³⁺ and ClO^-. Because the power supply capacity of H is weaker than that of methoxy, DQNS shows better optical performance: a large Stokes Shift (132 nm), identify Al³⁺ and ClO^- with high sensitivity and selectivity, low detection limit (29.8 nM and 25 nM) and fast response time (10 min and 10 s). Through the working curve and NMR titration experiment, the recognition mechanism of Al³⁺ and ClO^- (PET and ICT) probes are confirmed. Meanwhile, it is speculated that the probe has continuity for the detection of Al³⁺ and ClO^-. Furthermore, DQNS detection of Al³⁺ and ClO^- was applied to real water samples and living cell imaging.

Point-of-Care and Dual-Response Detection of Hydrazine/Hypochlorite-Based on a Smart Hydrogel Sensor and Applications in Information Security and Bioimaging

A novel dual-response fluorescence probe (XBT-CN) was developed by using a fluorescence priming strategy for quantitative monitoring and visualization of hydrazine (N2H4) and hypochlorite (ClO-). With the addition of N2H4/ClO-, the cleavage reaction of C=C bond initiated by N2H4/ClO- was transformed into corresponding hydrazone and aldehyde derivatives, inducing the probe XBT-CN appeared a fluorescence "off-on" response, which was verified by DFT calculation. HRMS spectra were also conducted to confirm the sensitive mechanism of XBT-CN to N2H4 and ClO-. The probe XBT-CN had an obvious fluorescence response to N2H4 and ClO-, which caused a significant color change in unprotected eyes. In addition, the detection limits of XBT-CN for N2H4 and ClO- were 27 nM and 34 nM, respectively. Interference tests showed that other competitive analytes could hardly interfere with the detection of N2H4 and ClO- in a complex environment. In order to realize the point-of-care detection of N2H4 and ClO-, an XBT-CN@hydrogel test kit combined with a portable smartphone was developed. Furthermore, the portable test kit has been applied to the detection of N2H4 and ClO- in a real-world environment and food samples, and a series of good results have been achieved. Attractively, we demonstrated that XBT-CN@hydrogel was successfully applied as an encryption ink in the field of information security. Finally, the probe can also be used to monitor and distinguish N2H4 and ClO- in living cells, exhibiting excellent biocompatibility and low cytotoxicity.

A highly sensitive ratiometric fluorescent probe based on fluorescein coumarin for detecting hydrazine in actual water and biological samples

Hydrazine (N₂ H₄ ) is a highly toxic and harmful chemical reagent. Fluorescent probes are simple and efficient tools for sensitive monitoring of N₂ H₄ enrichment in the environment, humans, animals, and plants. In this work, a ratiometric fluorescent probe (FP-1) containing coumarin was used for hydrazine detection. The proposed FP-1 probe had a linear detection range of 0-250 μM and a limit of detection (LOD) of 0.059 μM (1.89 ppb). A large red Stokes shift was observed in fluorescence and UV-vis absorption spectra due to the hydrolysis of ester bonds between FP-1 and hydrazine. The hydrazine detection mechanism of FP-1 was also investigated using density functional theory (DFT) calculations. Finally, FP-1 could sensitively and selectively monitor hydrazine in actual water samples and BEAS-2B cells. Therefore, it has great application potential in environmental monitoring and disease diagnosis.

A smartphone-adaptable chromogenic and fluorogenic sensor for rapid visual detection of toxic hydrazine in the environment

Hydrazine is an essential chemical in industries, but its high toxicity poses great threats to human health and environmental safety. Hence, it is of great significance to monitor the hydrazine in environment. In this work, we presented a chromogenic and fluorogenic dual-mode sensor RA for the detection of hydrazine based on nucleophilic substitution reaction. A linear relationship was obtained between the fluorescence intensity and the concentrations of N₂H₄ ranging from 0 to 35 μM (R² = 0.9936). The sensor can determine hydrazine with fast response (within 12 min), low limit of detection (0.129 μM) and high selectivity. RA was successfully used to detect N₂H₄ in real water samples with good recoveries and the results corresponded to the standard method. Furthermore, the sensor-coated portable test papers were fabricated, which can visually quantify hydrazine solutions with obvious fluorescence transformation from colorless to red. Moreover, RA-loaded papers were used to create a smartphone-adaptable RGB values analytical method for quantitative N₂H₄ detection.

A hemicyanine-based near-infrared fluorescent probe for vapor-phase hydrazine detection and bioimaging in a complete aqueous media

A novel near-infrared fluorescent probe CyOE based on hemicyanine dye containing acetyl as a recognition site is reported. The probe CyOE shows high selectivity and sensitivity (LOD = 82 nM, 2.58 ppb), as well as good water solubility and quantitative detectability of hydrazine in the concentration range of 0-75 μM (R² = 0.993). Moreover, CyOE has a significant increase in fluorescence at 735 nm with the addition of N₂H₄, which provides a rapid, colorimetric and gas-phase detection method for N₂H₄ in both aqueous solution and real water samples. In addition, CyOE is successfully utilized to visualize hydrazine in cells with low cytotoxicity and high cell permeability.

A lysosomal targeted fluorescent probe based on coumarin for monitoring hydrazine in living cells with high performance

A lysosomal targeted fluorescent probe based on coumarin for monitoring hydrazine (N₂H₄) in living cells was designed and synthesised. The novel fluorescent probe Cou-Lyso-N2H4, in response to N₂H₄, exhibited good selectivity, low cytotoxicity, and lysosomal localization, which could be suitable for studying the harmfulness of N₂H₄ in subcellular organelles during various physiological processes.

Dual-channel colorimetric fluorescent probe for determination of hydrazine and mercury ion

Hydrazine and mercury (Hg) poisoning represented a serious hazard to human health. So, developing method to detect and recognize them is highly desirable. Here, we prepared a multifunctional colorimetric and fluorescent probe (PI-Rh) consisting of a phenanthroimidazole (PI) dye conjugated with a Rhodamine (Rh) group for the effective recognition of hydrazine and Hg²⁺, induvidually and collectively, with different colorimetric and fluorescence outputs. Probe PI-Rh displays low detection limits measured to be 0.0632 μM (~2 ppb) and 0.0101 μM (~2 ppb) respectively for hydrazine and Hg²⁺ with high selectivity and excellent sensitivity. Moreover, the experimental results indicated that the superiority of this probe lied in its wide applications, for example, successful response in real water, and soil analysis. Interestingly, an visual, rapid, and real-time detection of gaseous hydrazine can be realized with 0.2793 μM detection limit using the facile PI-Rh-impregnated test paper.

One-step construction of a novel AIE probe based on diaminomaleonitrile and its application in double-detection of hypochlorites and formaldehyde gas

A novel and efficient probe with AIE property was designed and synthesized for application in double-detection of hypochlorites and formaldehyde gas.