A novel PBT-based fluorescent probe for hydrazine detection and its application in living cells

Cinnamyl Chalcone Based AIE Fluorescent Probes for Sensitive Detection of Hydrazine and its Application in Living Cells

Widely utilized in the chemical industry and agriculture, hydrazine is easily absorbed by living things and can cause physical harm when in touch for an extended period of time. As a result, a novel cinnamaldehyde chalcone C5 was produced by Friedel Crafts process and aldol condensation reaction. Triphenylamine was used as the raw material for hydrazine determination in both reactions. Chalcone C5 exhibits significant AIE behavior in a mixed mixture of ethanol and water in addition to having great selectivity and a low detection limit (0.119 nm) for hydrazine. The solvent effect test revealed a linear relationship between the Stokes shift of C5 in the solvent and the rise in solvent orientation polarization. It is important to note that C5 is not harmful to MCF-7 cells, mouse kidney cells, or pig kidney cells. Furthermore, research on cell imaging has demonstrated that probe C5 may be utilized to image the fluorescence of hydrazine in active MCF-7 cells.

Turn-on Coumarin Precursor: From Hydrazine Sensor to Covalent Inhibition and Fluorescence Detection of Rabbit Muscle Aldolase

Hydrazine, a highly toxic compound, demands sensitive and selective detection methods. Building upon our previous studies with pre-coumarin OFF-ON sensors for fluoride anions, we extended our strategy to hydrazine sensing by adapting phenol protecting groups (propionate, levulinate, and γ-bromobutanoate) to our pre-coumarin scaffold. These probes reacted with hydrazine, yielding a fluorescent signal with low micromolar limits of detection. Mechanistic studies revealed that hydrazine deprotection may be outperformed by a retro-Knoevenagel reaction, where hydrazine acts as a nucleophile and a base yielding a fluorescent diimide compound (6,6'-((1E,1'E)-hydrazine-1,2diylidenebis(methaneylylidene))bis(3(diethylamino)phenol, 7). Additionally, our pre-coumarins unexpectedly reacted with primary amines, generating a fluorescent signal corresponding to phenol deprotection followed by cyclization and coumarin formation. The potential of compound 3 as a theranostic Turn-On coumarin precursor was also explored. We propose that its reaction with ALDOA produced a γ-lactam, blocking the catalytic nucleophilic amine in the enzyme's binding site. The cleavage of the ester group in compound 3 induced the formation of fluorescent coumarin 4. This fluorescent signal was proportional to ALDOA concentration, demonstrating the potential of compound 3 for future theranostic studies in vivo.

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.

Theoretical Insights on the Sensing Performance for Newly-synthesized Two-photon Fluorescent N2H4 Probes Based on Spirobifluorence

The development of fluorescent probe for hydrazine (N2H4) detection has attracted much attention due to the important role of N2H4 plays in the fields of medicine, agriculture, biology and environments. In this paper, the optical properties and water solubility of two novel two-photon fluorescent molecular probes (Probe1 and Probe2) before and after the reaction with N2H4 are studied by using the density function theory. The results show that electronic distribution and transition dipole moment of the probes are obviously changed after the reaction with N2H4, thus the optical properties of the molecules are influenced and the detection of N2H4 are realized. In addition, photoinduced electron transfer processes for Probe1 and Probe2 in the presence of N2H4 are theoretically characterized, which explains the experimental observations from the microscopic mechanism. Special attention has been paid on the analysis of the two-photon absorption for the probes with the absence and presence of N2H4 by the response theory method. Both probes with good water solubility show large variation on the two-photon absorption cross section when reacts with N2H4. In particular, the two-photon absorption response of Probe2 is more obvious, so it possesses preferable two-photon fluorescence microscopic imaging ability. More importantly, the receptor effect on the sensing performances of the probes are demonstrated, providing a theoretical reference for the design and synthesis on more efficient two-photon fluorescence N2H4 probes. Our study provides necessary information on the response mechanism of the studied chemosensors and helps to establish the relationship between the structure and optical properties of two-photon fluorescence N2H4 probes.

A fluorescent probe based on triphenylamine with AIE and ICT characteristics for hydrazine detection

A fluorescent probe MAM based on triphenylamine scaffold was synthesized. The electron donating group 4-methoxyphenyl and the electron acceptor dicyanoethylene were introduced on the triphenylamine scaffold to form a D-π-A fluorescent probe. The probe MAM exhibited the typical aggregation-induced emission (AIE) and intramolecular charge transfer (ICT) characteristics with the bright orange-red fluorescent emission in high water fraction (f_w ≥ 50%) and negligible emission in low water fraction. The probe MAM could detect hydrazine (N₂H₄) in DMSO-tris-HCl (10 mM, pH7.4, v/v, 3:1) with high selectivity and sensitivity. The specific reaction between MAM and hydrazine and the formation of the hydrazone blocked the ICT process, and the system emitted the cyan fluorescence which could be easily observed by naked eyes. The limit of detection (LOD) was 0.196 μM (6.25 ppb), which is lower than the US Environmental Protection Agency standard (10 ppb). The test strips prepared by the probe MAM could realize the convenient and rapid detection of N₂H₄ solution and vapor. The application of MAM in actual water samples and cells was investigated, and the results showed that MAM could sense N₂H₄ in environmental and biological aspects with potential application prospects.

Switching to a 'turn-on' fluorescent probe for rapid detection of hydrazine in human breast cancer cells using a test-strip

A fluorescent probe TPSBT was developed to monitor hydrazine detection with a "turn on" response, converting from a "non-responsive" probe by a simple structural modification. The probe shows very weak fluorescence due to the strong ICT process and upon treatment with hydrazine, green fluorescence appears due to the blocking of this ICT by the formation of a hydrazone. The probe TPSBT can detect hydrazine with a very low detection limit (1.22 × 10^-7 M) and within a very short time period of 50 s. Additionally, the probe is able to give a response in live cell imaging (MDA-MB 231) and also in the solid phase.

A colorimetric and fluorometric probe for phenylhydrazine and its application in real samples

A fluorescent probe for phenylhydrazine detection was developed with aldehyde as the recognition group and good selectivity towards phenylhydrazine over hydrazine, hydroxylamine and other amines was observed. Its application in real water samples and fast visualization of phenylhydrazine using a probe-loaded paper strip were demonstrated.

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 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.

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 novel berberine-based colorimetric and fluorimetric probe for hydrazine detection

Hydrazine in water and soil has caused serious diseases for human health. In this work, a simple fluorescent probe (BP) for hydrazine detection was synthesized from berberine. The probe has excellent fluorescence properties and naked-eye detection.

Tetrathienylethene-based Positional Isomers with Aggregation-induced Emission Enabling Super Red-shifted Reversible Mechanochromism and Naked-eye Sensing of Hydrazine Vapor

AIE-active positional isomers, TTE-o-PhCHO, TTE-m-PhCHO and TTE-p-PhCHO, tetrathienylethene (TTE) derivates with peripherally attached ortho-/meta-/para-formyl phenyl groups, were designed and synthesized. The formyl substitution position can effectively modulate their photophysical properties, mechanochromism and fluorescent response to hydrazine. TTE-o-PhCHO and TTE-m-PhCHO exhibit remarkable AIE characteristics, and TTE-p-PhCHO possesses aggregation-induced emission enhancement performance. They all exhibit high contrast mechanochromism, and TTE-m-PhCHO shows larger red-shift (164 nm) than TTE-o-PhCHO (104 nm) and TTE-p-PhCHO (125 nm) due to the more twisted molecular conformation and much looser molecular packing. Moreover, TTE-o-PhCHO with a higher contrast color change can be used as ink-free rewritable paper. In addition, TTE-p-PhCHO, as a turn-on fluorescent probe, can selectively detect hydrazine with significant color changes that are visible by the naked eye . Therefore, the position dependence of groups would be an effective method to modulate the molecular arrangement, as well as develop AIE compounds for mechano-stimuli responsive materials, ink-free rewritable papers and chemosensors.

Development of Azo-Based Turn-On Chemical Array System for Hydrazine Detection with Fluorescence Pattern Analysis

A facile turn-on chemical sensor array was developed for hydrazine detection by means of fluorescence pattern recognition. Taking advantage of the unique properties of the azo group, four different fluorogenic probes, Seoul-Fluor (SF)-Azo 01-04, were designed and prepared. SF-Azo 01-04 displayed fluorescence enhancement of up to 800-fold upon reaction with hydrazine, and all probes exhibited excellent selectivity in the presence of various anions and nucleophiles. By employing the probes in a cellulose paper-based array system, the hydrazine concentration was successfully determined by monitoring the change in fluorescent patterns.

A dual-excitation fluorescent probe EuIII-dtpa-bis(HBT) for hydrazine detection in aqueous solutions and living cells

The Eu^III-dtpa-bis(HBT) dual-excitation fluorescence probe has good selectivity and strong anti-interference ability for the detection of N₂H₄.

A hybrid hydrazine redox flow battery with a reversible electron acceptor

Hydrazine is a pollutant with high hydrogen content, offering tremendous possibilities in a direct hydrazine fuel cell (DHFC) as it can be converted into electricity via benign end products. Due to the inner sphere nature of half-cell chemistries, hydrazine cross over triggers parasitic chemistry at the Pt-based air cathode of a state-of-the-art DHFC, overly complicating the already sluggish electrode kinetics at the positive electrode. Here, we illustrate that by altering the interfacial chemistry of the catholyte from inner sphere to outer sphere, the parasitic chemistry can be dissociated from the redox chemistry of the electron acceptor and the hybrid fuel cell can be driven by simple carbon-based cathodes. The reversible nature of an outer sphere catholyte leads to a hybrid fuel cell redox flow battery with performance metrics ∼4 times higher than a Pt-based DHFC-air configuration.