Probe For Detection Of Biothiols Research Articles

Theoretical investigation on a simple turn on fluorescent probe for detection of biothiols based on coumarin unit.

The discovery of a simple and efficient detection method for biothiols would be scientifically significant due to the crucial role of them in various physiological processes. Recently, a simple fluorescent probe, DEMCA-NBSC, based on coumarin fragments, was developed by Ding et al., and provided an efficient way for real-time sensing of biothiols both in vivo and vitro. Theoretical insights to the fluorescence sensing mechanism of the probe were provided in this work. Details of the electron transfer process in the probe under optical excitation and the fluorescent character of the probe were analyzed using a quantum mechanical method. All these theoretical results could inspire the development of a highly convenient and efficient fluorescent probe to sense biothiols both in vivo and vitro.

Novel near-infrared frequency up-conversion luminescence probe for monitoring biothiols in vitro and in vivo

Biothiols including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play important roles in the antioxidant activity of cells, and a variety of diseases could be linked to their abnormal levels. Frequency up-conversion luminescence (FUCL) probes have low background fluorescence and cause low tissue damage; thus it is less harmful than Stokes shift luminescence probes, the traditional fluorescence probes. However, the utilization of FUCL probes for detection of biothiols has rarely been reported. In this work, we designed and synthesized a near-infrared (NIR) xanthene derivative IFU-1 and used as a frequency up-conversion luminescence probe to detect biothiols. The probe IFU-1 had high selectivity for biothiols and exhibited enhanced FUCL signals in response to them. In addition, it has extremely low limit of detection with regards to different biothiols: 4.8 nM for Cys; 6.2 nM for Hcy, and 9.5 nM for GSH, which are about 10 times lower than the detection limit of traditional excitation methods (63 nM for Cys, 31 nM for Hcy, and 76 nM for GSH). This work presents a novel approach for constructing FUCL biosensors.

A new fluorescent ‘turn on’ probe for rapid detection of biothiols

ABSTRACT We designed and synthesised a novel molecular probe exhibiting high selectivity and sensitivity towards reactive sulphur species (RSS) over other amino acids and biologically relevant species, as well as scrutinised its spectroscopic behaviours under physiological conditions and in living milieu. We used an electrophilic cyanate group as a masking agent to block the excited state intramolecular proton transfer process of 2-(2-cyanato-3-methoxyphenyl)benzo[d]thiazole (HMBT-OCN), which readily hydrolyses to the highly fluorescent structure, 2-(2ʹ-Hydroxy-3ʹ-methoxyphenyl)benzothiazole (HMBT-OH), in the presence of reactive sulphur species.

A novel NIR fluorescence probe with cysteine-activated structure for specific detection of cysteine and its application in vitro and in vivo

Cysteine (Cys) as a vital antioxidant molecule and an effective biomarker for illness, plays an essential role in physiological functions and pathological processes. Extensive work has been done to explore the physiological functions of Cys and develop probes for detection of biothiols. However, the challenge to differentiate Cys from glutathione and homocystine remains. In this work, we constructed a novel near-infrared (NIR) probe, termed TMN-Cys, using TMN-NH2 and thionoesters. The probe could selectively detect Cys over homocysteine and glutathione in solution. It displayed a large Stokes shift (210 nm) upon treatment with Cys, and its detection limit was as low as 79 nM. Moreover, this probe showed low toxicity and was successfully employed in monitoring endogenous Cys in living cells and mice.

A 2, 7-naphthyridine-based fluorescent turn-on probe for detection of biothiols in vitro and in vivo

A 2,7-naphthyridine derivative (AND-OH) was used as a fluorophore in the development of a novel fluorescent turn-on probe (AND-DNBS) by introducing a 2,4-dinitrobenzenesulfonate functionality. This fluorescent probe was successfully used for sensing glutathione (GSH) in aqueous media and showed favorable properties such as a rapid response time (45 s) and a significant Stokes shift (227 nm). The characteristics of the developed probe are better than those of another probe, namely ND-DNBS, which was also synthesized by our group and most other previously reported fluorescent probes for GSH. The AND-DNBS probe was able to detect GSH via a red emission in living A549 cells and zebrafishes. These results show that AND-DNBS has potential applications as an excellent probe for detecting GSH in various environments.

Fluorescent probes for detection of biothiols based on “aromatic nucleophilic substitution-rearrangement” mechanism

Biothiols, including cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play important roles in physiological processes, and the detection of thiol using fluorescent probes has attracted attention due to their high sensitivity and selectively and invasive on-time imaging. However, the similar structures and reactivity of these biothiols present great challenges for selective detection. This review focused on the the “aromatic nucleophilic substitution-rearrangement (SNAr-rearrangement) mechanism”, which provided a powerful tool to design fluorescent probes for the discrimination between biothiols. We classify the fluorescent probes according to types of fluorophores, such as difluoroboron dipyrromethene (BODIPY), nitrobenzoxadiazole (NBD), cyanine, pyronin, naphthalimide, coumarin, and so on. We hope this review will inspire exploration of new fluorescent probes for biothiols and other relevant analytes.

A New Quinone Based Fluorescent Probe for High Sensitive and Selective Detection of Biothiols and Its Application in Living Cell Imaging.

In view of the vital role of biothiols in many physiological processes, the development of simple and efficient probe for the detection of biothiols is of great medical significance. In this work, we demonstrate the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), which respond rapidly to biothiols especially to glutathione, as a new fluorescent probe for the selective detection and bioimaging of biothiols. This new fluorescent probe can distinguish glutathione from cysteine and homocysteine easily under physiological concentration and detect glutathione quickly within three minutes. This probe exhibits high selectivity to biothiols and the detection limit was determined to be 3.08 × 10−9 M for glutathione, 8.55 × 10−8 M for cysteine, and 2.17 × 10−9 M for homocysteine, respectively. The sensing mechanism was further explored by density functional theory (DFT) and nuclear magnetic resonance (NMR) experiment; results showed that the interaction forces between the probe and biothiols were electrostatic interaction. In addition, the probe has been successfully applied to the detection of biothiols in Eca9706 cells by fluorescence confocal imaging technology.

Rapid and selective detection of biothiols by novel ruthenium(II) complex-based phosphorescence probes.

Considering the excellent photochemical properties of ruthenium(II) complexes, two new ruthenium(II) complexes, RuL1-DNBS and RuL2-DNBS, have been developed as phosphorescence probes for detection of biothiols in 100:1 (v/v) Hepes buffer (20 mM, pH = 7.2)/CH3CN solution. The response rate was highly improved of these two probes toward biothiols because the steric interactions between 1H-imidazo [4, 5-f] [1,10] phenanthroline group and ortho-2, 4-dinitrobenzensulfonate resulted in a relatively rapid thiol-induced SNAr substitution reaction. RuL1-DNBS and RuL2-DNBS were weakly phosphorescent owing to the effectual photoinduced electron transfer from ruthenium(II) luminophore to the sensing group, 2,4-dinitrobenzenesulfonyl. After reacting with biothiols, the 2,4-dinitrobenzenesulfonyl group of RuL1-DNBS and RuL2-DNBS were cleavaged and the RuL1 and RuL2 were obtained. Meanwhile, the phosphorescence were "turn-on". Both of these two probes can detect biothiols sensitively and selectively under physiological conditions with submicromolar detection limits. Furthermore, application of RuL2-DNBS for detecting of intracellular biothiols has been successfully performed in living Glioma cells.

Facile preparation of N,S-graphene oxide nanosheets as a fluorescence “off–on” sensing platform for sensitive detection of biothiols

Fluorescent N,S-graphene oxide was prepared via a one-step, solvent-free approach, and used as a probe for sensitive detection of biothiols.

A novel near-infrared and naked-eyes turn on fluorescent probe for detection of biothiols with a large Stokes shift and its application in living cells

A novel turn-on fluorescent probe (DDND) for highly selective detection of biothiols over other amino acids was synthesized and investigated in this work, which used the 2,4-dinitrobenzenesulfonyl group as a fluorescent quencher.

The synthesis and application of a lysosome-targeted-fluorescent probe for the detection of biothiols

As an important member of bio-active species, biological thiols have been proved to play pivotal roles in cellular growth in cells. In this paper, we have designed and synthesized a new coumarin-based off-on fluorescent probe (Lyso-thiol ) for the selective detection of biothiols in aqueous solution and in living cells. Lyso-thiol has been prepared by a 2-step procedure using morpholine as the lysosome-targeting group. The probe has successfully realized the linear quantitative detection of biothiols in a relatively large concentration scope. Moreover, under the saturated concentration of the biological thiols, the fluorescence intensity of the probe can be enhanced by as much as 745 times. The intracellular experiments have also confirmed the low cytotoxity and exceptional biocompatibility of the probe. It is validated both in HeLa and HepG 2 cells that Lyso-thiol is capable of specifically targeting lysosome and vividly imaging biothiols in cellular level.

A novel cyanobiphenyl benzothiazole-based fluorescent probe for detection of biothiols with a large Stokes shift and its application in cell imaging

An ESIPT-based fluorescent probe (Probe 1) with a large Stokes shift (202 nm) for the sensing of biothiols has been developed based on cyanobiphenyl benzothiazole derivative exhibiting larger Stokes shift than 2-(benzothiazol-2-yl)phenol. This probe with 2,4-dinitrobenzenesulfonate (DNBS) as a highly thiol-selective group was constructed based on the combination of excited state intramolecular proton transfer (ESIPT) and photoinduced electron transfer (PET) mechanisms. Upon the treatment with biothiols, this probe produced a remarkable fluorescence enhancement at 482 nm. The detect limits for Cys, GSH and Hcy was calculated to be as low as 2.0 × 10−8 M, 1.7 × 10−7 M and 1.2 × 10−7 M, respectively (based on S/N = 3). Importantly, application of this probe was successfully demonstrated by imaging thiols in living NCI-H226 cells.

Discrimination of biothiols in different media with NBD-F as the probe

Abstract 4-Fluoro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-F) was employed as a colorimetric probe for differential detection of biothiols in different media. The spectral response and the selectivity of NBD-F toward thiols were significantly improved by surfactant micelles. Mercapto group exhibited high reactivity in all the solvents (including Tris–HCl buffer solution, CTAB and SDS micelles). The 4-thioether derivatives of NBD-F reacting with Cys and Hcy but not GSH could transfer to the corresponding 4-amino-substituents via intramolecular nucleophilic aromatic substitution, thus, GSH could be discriminated from Cys/Hcy. In CTAB micelles, the reaction product of NBD-F with Cys is non-fluorescent and it absorbs in long-wavelength region. According to the spectral responses of NBD-F toward different low-molecular-weight thiols, we could identify Cys, Hcy and GSH from each other.

Bovine serum albumin‐confined silver nanoclusters as fluorometric probe for detection of biothiols

Fluorescent bovine serum albumin-confined silver nanoclusters (BSA-AgNCs) were demonstrated to be a novel and environmentally friendly probe for the rapid detection of biothiols such as cysteine (Cys), homocysteine (Hcy) and glutathione (GSH). The sensing was ascribed to the strong affinity between the mercapto group of the biothiols and the silver nanoclusters. The fluorescence intensity of BSA-AgNCs was quenched efficiently on increasing the concentration of biothiol, corresponding with a red-shift in emission wavelength. However, the fluorescence of the silver nanoclusters was almost unchanged in the presence of other α-amino acids at 10-fold higher concentrations. By virtue of this specific response, a new, simple and rapid fluorescent method for detecting biothiols has been developed. The linear ranges for Cys, Hcy and GSH were 2.0 × 10(-6) to 9.0 × 10(-5) M (R(2) = 0.994), 2.0 × 10(-6) to 1.2 × 10(-4) M (R(2) = 0.996) and 1.0 × 10(-5) to 8.0 × 10(-5) M (R(2) = 0.980), respectively. The detection limits were 8.1 × 10(-7) M for Cys, 1.0 × 10(-6) M for Hcy and 1.1 × 10(-6) M for GSH. Our proposed method was successfully applied to the determination of thiols in human plasma and the recovery was 94.83-105.24%. It is potentially applicable to protein-stabilized silver nanoclusters in a chemical or biochemical sensing system.