Pyrene-based Fluorescent Probe Research Articles

An endoplasmic reticulum-targeted ratiometric fluorescent probe for hypochlorite bioimaging based on aggregation-induced ratiometric emission

A novel pyrene-based fluorescent probe was synthesized, with an aggregation-induced ratiometric emission (AIRE) at 525 nm in 99% H2O solution (containing 1% DMSO). This AIRE was quenched, and a new blue emission at 470 nm was detected after adding hypochlorite (ClO−), according to a fast (within 20 s) and sensitive (detection limit of 269 nM) ratiometric fluorescent response to ClO−. The sensing mechanism of the probe to ClO− was assessed by ESI-MS, transmission electron microscopy, time-resolved fluorescence measurements, and density functional theory. In addition, the probe is equipped with p-toluenesulfonamide as the endoplasmic reticulum (ER) localization group, and has been applied to the imaging of endogenous and exogenous ClO− in both living cells and zebrafish.

A reversible pyrene-based fluorescent probe for visual detection of cysteine in food samples

A reversible fluorescent probe Pyr-1 was developed by integrating pyrene and oxime functional groups and applied for visual detection of Cysteine (Cys). By featuring three binding sites, Pyr-1 exhibited selective fluorescence quenching response towards Fe3+ through the formation of 1:1 coordination complex. The ensemble Pyr-1-Fe3+ was further applied to detect Cys. Among the various test species, Cys induced unique fluorescence enhancement through the decomplexation process. The detection of Cys exhibited a fluorescence “turn-off-on” phenomenon within 50 s and reversible cycle performed up to at least 32 times. The detection limit was calculated as 0.446 µM. Due to the excellent stability in wide pH range (2−11), Pyr-1-Fe3+ was successfully applied in detection of Cys in diverse food samples. In practical applications, an obvious fluorescent color difference was observed on paper-based device modified by Pyr-1-Fe3+, which was convenient and could be used for on-site evaluation of Cys in food samples.

Pyrene-Based Fluorescent Probe for “Off-on-Off” Sequential Detection of Cu2+ and CN− with HeLa Cells Imaging

The novel pyrene-appended Schiff base probe L with aggregation-induced emissions (AIE) relevant to an increase in water fractions (0–90%) is synthesized and applied in sequentially detecting Cu2+ and CN−. The pyrene-based probe L firstly induces the excimer formation in the presence of Cu2+. However, the process can be reversed by sequentially adding CN−, which is demonstrated using the fluorescence “Off-On-Off” response in semi-aqueous media ethanol water (v/v = 7/3) under physiological pH (5 mM HEPES, pH 7.0). The Job’s plot, mass analysis, 1H NMR titrations, and density functional theory (DFT) interrogations confirm the 2:1 stoichiometry of excimer complex L–Cu2+-L*, preferential binding atoms, and CN− tuned complex reversibility. Based on the photoluminescence (PL) titration, the association constant of L to Cu2+ is determined as 4.95 × 106 M−1. From standard deviation and linear fittings, the detection limits (LODs) of Cu2+ and CN− are estimated as 219 nM and 580 nM, respectively. The practicality of Cu2+ and CN− detection is demonstrated using a TLC plate and a blended polymer membrane through which significant color changes under a UV lamp can be monitored. Moreover, utility of the designed probe L towards biological application with low toxicity is demonstrated by detecting Cu2+ and CN− inside HeLa cells. The responses of the probe to Cu(II) ions were also verified using living HeLa cells imaging.

Cardiomyocyte mitochondrial respiration and microviscosity in rats of different ages in heart failure

Highlights. Heart failure in older age groups is an urgent medical and social issue. Mitochondrial dysfunction is a key link in the pathogenesis of heart failure. In this study we have demonstrated a decrease in mitochondrial respiratory function in old rats. In this age group, the development of heart failure is accompanied by a further decrease in respiratory control. An increase in the mitochondrial microviscosity in older animals may affect the activity of respiratory chain enzymes in heart failure.Aim. To study the respiratory activity and mitochondrial membrane microviscosity of cardiomyocyte of rats of different ages with heart failure.Methods. The study involved 22 2- and 15-month-old male Wistar rats. The animals were divided into 4 groups: 2 groups of intact animals of both ages (n = 12) and 2 groups of rats with isadrine model of heart failure (HF) (n = 10). HF was modeled by two subcutaneous injections of isoproterenol hydrochloride (170 mg/kg) at interval of 24 hours. Mitochondrial respiratory activity was assessed using respiratory control coefficient. The microviscosity of mitochondrial membranes was evaluated by eximerization coefficients of pyrene-based fluorescent probe in areas of protein-lipid and lipid-lipid contact. Comparative statistical analysis of independent groups was performed using the nonparametric Mann-Whitney test.Results. A decrease in mitochondrial respiratory control in older rats was shown in comparison with young animals. In the HF model, inter-age difference increases, but at the same time, in younger rats, the development of HF is not accompanied by significant changes in mitochondrial respiratory control. An age dependent decrease in the microviscosity of mitochondrial membranes in the area of protein-lipid and lipid-lipid interaction was revealed. In younger rats, the development of HF is characterized by a significant increase in microviscosity in the area of protein-lipid and lipid-lipid contact. In older rats, the development of the pathology is characterized by a significant decrease in microviscosity in the area of protein-lipid interaction.Conclusion. Multidirectional age-related changes in cardiomyocyte mitochondria of rats with heart failure were revealed. It was shown that mitochondria in younger rats retain their functional activity in the HF model unlike older rats.

One-step synthesis of a pH switched pyrene-based fluorescent probe for ratiometric detection of HS- in real water samples.

Only a few probes are suited for highly acidic environments and sensitive to pH values below 4. Thus, finding a solution for detecting strong acidic (pH value below 2) conditions is still challenging. Herein, we constructed and created a pH-switched fluorescent probe based on pyrene and a heteroatom containing pyridine unit. When exposed to acidic environments (pH 2.0), the probe's fluorescence redshifted with distinct colour and fluorescence changes owing to protonation on the nitrogen atom containing pyridine moiety, which could be deprotonated by HS- selectively compared to other competing analytes. Pyr can detect HS- with a rapid response within 5 s and showed very good quantum yield under acidic environments. The sensing mechanism was confirmed by Density Functional Theory (DFT) studies using the B3LYP and 6-31G+ (d) basis sets. Furthermore, the probe was utilized to monitor HS- in actual water samples and identify H2S gas by a simple paper strip test.

Synergetic effect of pyrene-based fluorescent probes for trace nitroaniline sensing

This article presents a new pyrene-based fluorescent probe for p-nitroaniline detection with a limit of detection as low as 6.18 × 10−9 M.

A novel pyrene-based fluorescent probe for Al3+ detection

Based on the classical Schiff base reaction, fluorescent probe dimethyl 5-((pyren-1-ylmethylene)amino)isophthalate (PAI) is designed and synthesized through introducing Schiff base structure to pyrene unit for structural modification. The structure of the synthesized probe PAI is determined and characterized by FT-IR, 1H NMR, 13C NMR and HRMS. PAI is a type of “turn-on” probe which can specifically recognize Al3+ ion with high selectivity. The limit of detection is calculated to be 3.07 × 10−8 M, which proves the probe’s high sensitivity and is lower than that of many efficient reported probes. The probe PAI is intrinsically non-fluorescent due to the photoinduced electron transfer (PET) process. However, the addition of Al3+ ion leads to the breakage of the carbon–nitrogen double bond of Schiff base in PAI resulting in the product without PET property, which shows a typical localized state with enhanced fluorescence and blue color. In addition, PAI can recognize Al3+ ion through test papers, which is in favor of the future research regarding to Al3+ ion sensing.

Novel Docetaxel-Loaded Micelles Based on all-trans-Retinoic Acid: Preparation and Pharmacokinetic Study in Rats

AbstractDocetaxel (DTX) is a poorly soluble drug. The purpose of this study was to explore a DTX-loaded micelle delivery system using N-(all-trans-retinoyl)-L-cysteic acid methyl ester sodium salt (XMeNa) as the carrier materials. In this study, amphiphilic surfactant XMeNa was synthesized. Then, the blood biocompatibility and the value of critical micelle concentration (CMC) were assessed by a hemolysis test and pyrene-based fluorescent probe techniques, respectively. The XM-DTX micelles were prepared using the method of thin-film hydration, and characterized by dynamic light scattering and transmission electron microscopy (TEM). The entrapment efficiency (EE) and drug loading efficiency (DLE) were assessed by the ultrafiltration method. In vitro release and pharmacokinetic behaviors of XM-DTX micelles were performed in rats using Taxotere (a commercialized DTX injection) as a control. Our data confirmed the excellent blood biocompatibility of XMeNa as a carrier. XMeNa can self-assemble into micelles in aqueous media with a very low CMC (6.2 μg/mL). The average size and zeta potential of the XM-DTX micelles were 17.3 ± 0.2 nm, and −41.6 ± 0.3 mV, respectively. EE and DLE reached up to 95.3 ± 0.7% and 22.4 ± 0.2%, respectively, which may account for the high solubility of DTX in normal saline. The micelles were spherical in TEM with good dispersion and no aggregation and adhesion, and exhibited good stability after reconstitution over 8 hours. Results from in vitro release assay suggested a much slower release behavior of XM-DTX micelles in comparison to Taxotere. Additionally, XM-DTX micelles prolonged DTX retention in blood circulation, increased the area under the curve by 2.4-fold, and significantly decreased the clearance of the drug. Given above, the XM-DTX micelles could improve the solubility and the release of DTX. The amphiphilic surfactant XMeNa also exhibited great potential as a vehicle for exploring delivery of poorly water soluble drugs in the future.

Synthesis of a dual-emissive pyrene-based fluorescent probe for imaging intracellular viscosity

A pyrene-based fluorescent molecular probe (Py2-5EG) was synthesized for optical detection of viscosity variation. Py2-5EG was synthesized by the reaction of two hydroxyl groups at the two ends of pentaethylene glycol with pyrene via a two-step reaction. Unlike typical pyrene compounds, the monomer fluorescence of Py2-5EG was not observed even in a dilute solution. Instead, the monomer fluorescence gradually increased with the increase in solvent viscosity. Blue fluorescent emission was observed from the monomer in a more viscous medium, and greenish blue emission from excimer was dominant in a less viscous medium in which dynamic excimer formation was involved. The observed fluorescence change of Py2-5EG was ratiometric and depended on the solution viscosity. A microscopic change in cellular viscosity was clearly observed inside and outside the mitochondria of living cells via different fluorescence colors of blue and green. The viscosity inside and outside mitochondria was determined using the fluorescence colors. Py2-5EG featured noticeable fluorescence emission shift in response to viscosity, and this phenomenon can be applied as a fluorescent probe, estimating the viscosity of various solutions as well as inside living cells.

Multi-dentate chelation induces fluorescence enhancement of pyrene moiety for highly selective detection of Fe(III).

Fluorescence enhancement has great advantages and various promising applications for a fluorescent molecular probe, which shows high sensitivity and high selectivity. In this report, a novel pyrene-based fluorescent probe with multidentate ligand (PPD) was synthesized for highly selective detection of Fe(III), which exhibited great fluorescence enhancement response upon the addition of Fe(III) in aqueous solution of pH 3.5 ~ 7.5, with a detection limit of 115nM. The probe also has good water solubility and photostability. Further fluorescence titration confirmed 1:1 stoichiometric ratio for the probe PPD-Fe(III), which can be applied for quantification of Fe(III). The probe was validated for ferric detection in real water samples by spike and recovery test.

A Pyrene-Based Fluorescent Probe for Specific Detection of Cysteine and its Application in Living Cell.

Cysteine (Cys) is an essential amino acid in organism, which is transformed from methionine in vivo and participates in protein synthesis and cell redox process. Therefore, the detection of Cys is of great significance. In this work, a novel fluorescent probe, (E)-3-(2-chloroquinolin-3-yl)-1-(pyren-3-yl) prop-2-en-1-one (PAQ) was designed and synthesized to specifically detect Cys. The response mechanism of the reaction between PAQ and Cys was due to the addition reaction of Cys to α,β-unsaturated ketone of PAQ. Interestingly, the addition of Cys induced significant fluorescence intensity enhancement at 462nm. PAQ exhibited favorable sensing properties towards Cys such as the low limit of detection (0.27μM) and fast response speed (2min). In addition, PAQ displayed high selectivity and anti-interference ability toward Cys among various analytes. Notably, PAQ has been successfully used to image exogenous and endogenous Cys in HeLa cells.

Pyrene Excimer-Based Fluorescent Labeling of Cysteines Brought into Close Proximity by Protein Dynamics: ASEM-Induced Thiol-Ene Click Reaction for High Spatial Resolution CLEM.

Fluorescence microscopy (FM) has revealed vital molecular mechanisms of life. Mainly, molecules labeled by fluorescent probes are imaged. However, the diversity of labeling probes and their functions remain limited. We synthesized a pyrene-based fluorescent probe targeting SH groups, which are important for protein folding and oxidative stress sensing in cells. The labeling achieved employs thiol-ene click reactions between the probes and SH groups and is triggered by irradiation by UV light or an electron beam. When two tagged pyrene groups were close enough to be excited as a dimer (excimer), they showed red-shifted fluorescence; theoretically, the proximity of two SH residues within ~30 Å can thus be monitored. Moreover, correlative light/electron microscopy (CLEM) was achieved using our atmospheric scanning electron microscope (ASEM); radicals formed in liquid by the electron beam caused the thiol-ene click reactions, and excimer fluorescence of the labeled proteins in cells and tissues was visualized by FM. Since the fluorescent labeling is induced by a narrow electron beam, high spatial resolution labeling is expected. The method can be widely applied to biological fields, for example, to study protein dynamics with or without cysteine mutagenesis, and to beam-induced micro-fabrication and the precise post-modification of materials.

A novel pyrene-based fluorescent probe for the rapid and efficient detection of Co2+ in HeLa cells and natural water samples

Excessive levels of Co2+ in the environment can cause serious diseases to humans and affect the growth of crops. Therefore, it is necessary to develop effective methods for monitoring Co2+. In the present work, a novel, low-toxic fluorescent probe, PEPA, for the rapid and efficient detection of Co2+ is synthesized. PEPA shows high sensitivity, with a limit of detection of 0.104 μM and a fast response to Co2+ (<4 min). The detection mechanism was confirmed by FT-IR, HRMS and DFT calculations. Co2+ can restrict the free rotation of the CN group and the pyrazine ring of PEPA, resulting in the enhancement of fluorescence. In addition, the recognition process of Co2+ can be realized with the naked eye (i.e., a color change from colorless to blue fluorescence). The successful detection of Co2+ in test strips and environmental water samples provides strong support for its application potential. Interestingly, the recovery rate of Co2+ detected by PEPA can reach 93% after being recovered four times. Importantly, PEPA was suitable for the fluorescence imaging of exogenous Co2+ in HeLa cells.

Self-Assembly of Nanoscale Induced Excimers of 12-Pyren-1-yldodecanoic Acid for TNT Detection

We report nanoscale pyrenyl excimers induced by the self-assembly of a pyrene-based fluorescent probe, 12-pyren-1-yldodecanoic acid (PyDA), for rapid detection of 2,4,6-trinitrotoluene (TNT) in aqu...

Mechanistic and thermodynamic aspects of a pyrene-based fluorescent probe to detect picric acid

Thermodynamic investigation of picric acid sensing using a pyrene-based fluorescent probe.

A simple pyrene-based fluorescent probe for highly selective detection of formaldehyde and its application in live-cell imaging

A novel and simple pyrene-based fluorescent probe (B1) was synthesized and used for the detection of formaldehyde (FA). When B1 was added to FA in CH3CH2OH/HEPES (10 mM, pH = 7.4, 1:99, v/v) solution, the solution system strongly enhanced the fluorescence. Over various small molecular species, probe B1 showed high sensitivity and selectivity for detecting FA, with a low limit of detection (0.107 μM). Furthermore, probe B1 was successfully applied for visualizing FA in human embryonic kidney (HEK293T) cells, demonstrating its value of application in living biomedical samples.

Ultrasensitive detection of thiophenol based on a water-soluble pyrenyl probe

We report a simple pyrene-based fluorescent probe, sodium 8-(2,4-dinitrophenoxy)pyrene-1,3,6-trisulfonate (HPTS-DNP), for the ultrasensitive and visual detection of thiophenol in 100% aqueous media. The sensing mechanism of this method is based on nucleophilic aromatic substitution on HPTS-DNP caused by thiophenol to afford a highly fluorescent product, 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). The extremely low fluorescence background of HPTS-DNP and high quantum yield of HPTS ensure the superior sensing performance toward thiophenol, including rapid responses, off-on detection mode and excellent sensitivity. The detection limit is as low as 0.49 nmol L−1 according to the measurements with a spectrofluorimeter. This probe also features good selectivity (response ratio of thiophenol to interferents >30), precision (2.93%) and accuracy (102%). This approach could be applied for monitoring the thiophenol concentrations in environmental water samples. HPTS-DNP also showed good cell permeation capacity and low cellular cytotoxicity, indicating further application in bioimaging studies.

A new pyrene-based fluorescent probe with large Stokes shift for detecting hydrogen peroxide in aqueous solution and living cells

Abstract Hydrogen peroxide (H 2 O 2 ) plays an important role in signal transduction and therapy of serious diseases. In this work, we have developed a new pyrene-based fluorescent probe Py-Boe , which possesses large Stokes shift and achieves detection of H 2 O 2 in aqueous solution. The probe Py-Boe exhibits excellent photostability, high sensitive and selectivity. Taking advantage of these properties, the probe Py-Boe achieves succussfully imaging of exogenous and endogenous H 2 O 2 in living RAW 264.7 cells. We expect that this dye with large Stokes shift may open an avenue to construct novel fluorescent probe with large Stokes shift for biological application.

A pyrene-based fast-responsive fluorescent probe for G-quadruplexes

A novel pyrene-based fluorescent probe (3-methyl-2-(pyren-1-yl)benzo[d]thiazol-3-ium iodide) (PBT) was found to be a fast-responsive and highly selective towards G-quadruplexes. PBT exhibited an opposite fluorescent variation tendency on binding with G-quadruplexes and ds-DNAs.

A novel pyrene based fluorescent probe for selective detection of cysteine in presence of other bio-thiols in living cells

This manuscript reports the synthesis of pyrene-based fluorescent probe (PA-1) containing α,β-unsaturated carbonyl moiety and its application towards the selective and sensitive detection of cysteine (Cys) over other bio-thiols. The probe, 3-(2-hydroxyphenyl)-1-pyrenyl-2-propenone (PA-1) was synthesized through Claisen-Schmidt condensation between acetyl pyrene and salicylaldehyde. The formed product was characterized by 1H NMR, 13C NMR and GC–MS techniques. The probe exhibited absorption maximum at 374nm and emission maximum at 467nm (λex=342nm). The emission intensity of PA-1 was greatly enhanced while adding 2.5nM Cys. This can be attributed to the nucleophilic attack of Cys to the α,β-unsaturated ketone resulting in switching off, intramolecular charge transfer (ICT) from pyrene moiety to the phenolic nucleus. This was confirmed by DFT measurements. The PA-1 exhibited an excellent selectivity towards the determination of 40nM cys in the presence of 250,000-fold higher concentration of common interferents. The emission intensity was linearly increased and the limit of detection was found to be 10pM/L (S/N=3). Interestingly, the response of the PA-1 towards Cys is less than 1min. The confocal laser scanning micrographs of HeLa cells confirmed the cell permeability of the PA-1 and its ability to selectively detect Cys in living cells. In addition, the proposed probe was successfully applied for the determination of Cys in blood serum samples.