Fluorescent Probe For Specific Detection Research Articles

A near-infrared turn on fluorescent probe for specific detection of cysteine and its application based on a corrole fluorophore

A near-infrared turn on fluorescent probe for specific detection of cysteine and its application based on a corrole fluorophore

A sensitive PET “turn on” fluorescent probe for specific detection of 4-methoxy-thiophenol

Thiophenols as a series of industrial products are widely used and high toxicity to the organisms and the environment. The fluorescent probe technique offers important insights into thiophenols convenient sensing. Herein, we report a 1,8-naphthalimide/ triphenylamine-based fluorescent probe (TPA-NI-NO2) for the specific detection of 4‑methoxy-thiophenol (MTP). The probe can “turn on” specific detect MTP with the limit of detection (LOD) of 80 nM among various relevant analytes and homologues (p-Cl-C6H4SH, p-NO2-C6H4SH, C6H5SH and o-CH3-C6H5SH). The sensing mechanism was explored by the HPLC experiment and the PET process was determined by density functional theory (DFT) calculations. In addition, the specificity of the probe was also studied by the Gibbs free energy (ΔG) analysis of the reaction between the probe and different thiophenols. The reaction between probe and MTP gives the minimum of the ΔG value (∼ -9.7280 kcal/mol) and that of other thiophenols-mediated is -2.5283 to -5.8911 kcal/mol, which proves the thermodynamic chemical equilibrium can optimize the design of reaction-based fluorescent probes with excellent specificity. At last, TPA-NI-NO2 was successfully applied to Hela cells imaging.

An extra-large Stokes shift near-infrared fluorescent probe for specific detection and imaging of cysteine

Cysteine (Cys) plays a crucial role in numerous physiological and pathological processes. Therefore, it is imperative to design a highly selective and sensitive near-infrared (NIR) fluorescent probe to monitor Cys. In this study, we have developed a novel NIR fluorescent probe XA based on Xanthene hybrid tetrahydro-acridine salt dye for specifically tracking of Cys, where a chlorine-substituted tetrahydro-acridine acts as a high Cys-reactive site and water-soluble group. Probe XA exhibits a remarkable "turn-on" NIR emission (830 nm) with an extra-large Stokes shift (305 nm) for monitoring Cys. It also has a high selectivity, rapid response time (6 min) and high sensitivity (LOD as 0.5 μM). We fully characterized and discussed the sensing mechanism of XA toward Cys using HPLC and MS spectrums, as well as quantum theory calculations. Furthermore, the excellent properties of NIR fluorescent detection allow this novel probe to successfully monitor fluctuations of exogenous and endogenous Cys concentration levels in living cells and in vivo.

New 1,8-naphthalimide-based colorimetric fluorescent probe for specific detection of hydrazine and its multi-functional applications

Detection of hydrazine is particularly important given its toxicity and extensive application in various industries. In the present paper, a colorimetric fluorescent probe NI-CIN based on 1,8-naphthalimide derivative was rationally designed and simply synthesized for specific detection of hydrazine based on the intramolecular charge transfer (ICT) mechanism. Upon the addition of hydrazine, a significant fluorescence enhancement at 556 nm could be observed within 4 min with a distinct color change from colorless to bright yellow, readily observed by naked eye. Except for HRMS and 1H NMR, density functional theory (DFT) calculations were also performed to support the sensing mechanism. In addition, eco-friendly paper test strips were easily prepared by NI-CIN for selective and real-time detection of hydrazine under aqueous and vapor phases. Furthermore, NI-CIN shows many potential applications for detecting hydrazine in real water and soil samples along with bio-imaging in HepG-2 cells and zebrafish.

A red-emitting ultrasensitive fluorescent probe for specific detection and biological visualization of cysteine in vitro and in vivo

Developing efficient strategies for specific detection of cysteine (Cys) is of great importance for identifying complicated biological roles in physiological and pathological processes. Herein, an ultrasensitive red-emission fluorescent probe (termed 1) is constructed for specific detection and biological visualization of Cys. The linked-anthocyanin fluorophore modified with a twisted N, N-diethylamino moiety shows improved red-shifted emission (642 nm) and absolute quantum yield (0.224 in dimethyl sulfoxide), as well as minimal fluorescence background signal and good water solubility. Meanwhile, utilizing acryloyl chloride as recognition group endows the probe 1 with excellent sensitivity and selectivity towards Cys (limit of detection: 2.93 nM). More importantly, the in vitro and in vivo results confirm that the probe 1 has the capacity of fluorescence imaging of Cys and good biological safety, which holds great promise for bioanalysis and biosensing of Cys.

Water-soluble fluorescent probe for specific detection of SO2 derivatives in food and cells

SO2, the fourth endogenous gaseous signaling molecule, plays an important role in cells. Besides, SO2 derivatives are used as preservatives in food and drinks. To understand the level of SO2 derivatives in body and food, we developed a FRET-based fluorescent probe CPO. CPO had high energy transfer efficiency and high selectivity toward SO2 derivatives. It could fast respond toward SO2 derivatives in an aqueous solution (3 min) and possessed a low detection limit (68 nM). Furthermore, the SO2 derivatives in tap water, sugar, vermicelli and cells were detected by probe CPO. In addition, probe CPO had a high colocalization coefficient (0.95) for lipid droplets.

A New Lysosome-Targeted NIR Fluorescent Probe for Specific Detection of Cysteine over Homocysteine and Glutathione.

In this paper, by modifying the thioxanthene-benzothiozolium fluorophore, BCy-Cys, a lysosome-targeted near-infrared (NIR) fluorescent probe was synthesized for the detection of cysteine (Cys) from homocysteine (Hcy)/glutathione (GSH). As expected, BCy-Cys exhibited high selectivity and high sensitivity for detection of Cys over Hcy/GSH, with an extremely low limit of detection at 0.31 μM, marked by obvious color changes. HRMS was conducted to confirm that the fluorescence intensity at 795 nm was significantly enhanced by the enhancement of intramolecular charge transfer (ICT). Importantly, BCy-Cys could be used to visualize both exogenous and endogenous lysosomal Cys, signifying its potential application in complex organismal systems.

Mitochondrial targeting fluorescent probe for specific detection of nickel ions and biological imaging

Nickel ion, a kind of essential trace element, is indispensable for maintaining life health. Nickel ions in excess will induce a series of reactions in the body and be correlative with the diseases and even cancer. As one of the most important organelles, mitochondrion is responsible for maintaining the homeostasis of metal ions in cells. Therefore, sensitive detection of nickel ions in mitochondria contributes to further study the physiological function of mitochondria, and is of great significance for investigating body health. In this study, a simple and effective fluorescence probe method for the detection of nickel ions in organisms and environment was proposed. The probe has shown excellent spectral performance in vitro experiments, and the detection limits was as low as 17 nM. And it can be applied to the detection of nickel ions in environmental water samples with satisfactory results, the recovery rate is higher than 85%. More importantly, the probe can specifically target to mitochondria to realize the imaging of nickel ions in cells and provide an effective auxiliary tool for in-depth study of the relationship between mitochondrial function and metal ions. In addition, the probe has been successfully applied to the detection of nickel ions in zebrafish model, which further demonstrates the great potential and value of the probe in biological applications.

A naphthalimide functionalized chitosan-based fluorescent probe for specific detection and efficient adsorption of Cu2+

As one of the most abundant metal ions, Cu2+ has turned into a great threat to human health and the natural environment due to its widely utilized in various industries. In this paper, a chitosan-based fluorescent probe CTS-NA-HY for detection and adsorption of Cu2+ was rationally prepared. CTS-NA-HY exhibited a specific “turn off” fluorescence response to Cu2+ and the fluorescence color changed from bright yellow to colorless. It possessed satisfactory detection performance to Cu2+ including good selectivity and anti-interference, low detection limit (29 nM) and wide pH range (4–9). The detection mechanism was confirmed by Job's plot, X-ray photoelectron spectroscopy, FT-IR and 1H NMR analysis. Additionally, the probe CTS-NA-HY was capacity of determining Cu2+ in environmental water and soil samples. Besides, CTS-NA-HY-based hydrogel could also remove Cu2+ in aqueous solution effectively, which the ability of adsorption was greatly improved compared with original chitosan hydrogel.

Blue Fluorescent Nitrogen‐Doped Carbon Dots for the Specific Detection of Mn2+

AbstractManganese is one of vital elements related to various diseases. Nowadays, few works can specifically respond to Mn2+ alone. Hence, it is still challenging for specific detection of Mn ion. In this work, nitrogen‐doped carbon dots (N‐CDs) with blue luminescence properties was prepared using nitrated pyrene and diethylenetriamine (DETA) via one‐step solvothermal process. N‐CDs were applied as a fluorescent probe for specific detection of Mn2+ because of their high selectivity and sensitivity. No apparent fluorescence interferences can be observed with various amino acids and metal ions. The minimum concentration detected was 5 nM. The quenching mechanism maybe attributed to dynamic quenching processes. Notably, in this work, a visual early‐warning of Mn content exceeding the standard in drinking water in the light of fluorescence quenching of N‐CDs was achieved, and the practical sensing of N‐CDs which performed in environmental water samples demonstrated the detection performance of N‐CDs in real samples.

A coumarin-based fluorescent probe for specific detection of cysteine in the lysosome of living cells

Cysteine (Cys), the only amino acid in the 20 natural amino acids that contains a reduced sulfhydryl group, plays important roles in the balance of redox homeostasis in biological systems. Lysosome is an important organelle containing a variety of hydrolases and has been proved to be the decomposition center of a variety of exogenous and endogenous macromolecular substances. In this research, a coumarin-based fluorescent probe MCA for the detection of Cys in lysosomes of living cells was developed. Due to the acrylate moiety, this probe exhibited high sensitivity (detection limit = 6.8 nM) and selectivity towards Cys superior to other analytes. Moreover, the probe was proved to be lysosome-targetable and showed good cell imaging ability and low cell toxicity.

Synthesis and mechanism study of two similar colorimetric fluorescent probes for specific detection of bisulfite and hypochlorite

Synthesis and mechanism study of two similar colorimetric fluorescent probes for specific detection of bisulfite and hypochlorite

Naphthalimide appended isoquinoline fluorescent probe for specific detection of Al3+ ions and its application in living cell imaging

Herein, a novel Schiff base fluorescent probe NIQ based on naphthalimide and iso-quinoline units has been readily prepared for the selective detection of Al3+ ions. The obviously visible color changes and prominent fluorescence enhancement were observed upon the addition of Al3+ to NIQ, which could be attributed to the complexation of NIQ with Al3+ and thus leading to the inhibition of photo-induced electron transfer (PET) and the chelation-enhanced fluorescence (CHEF) progress. The limit of detection (LOD) was 52 nM that was far below the standard recommended by the WHO. Binding ratio (1:1) of NIQ with Al3+ ions was supported by Job’s plot. The binding constant of NIQ for Al3+ were calculated to be 3.27 × 105 M−1 on the basis of benesi-Hildebrand plot. The plausible binding mechanism for NIQ towards Al3+ ions was evidenced by the density functional theory (DFT) and 1H NMR titration experiment. Furthermore, this “turn-on” probe NIQ has been successfully applied as a biomarker for imaging the Al3+ ions in living cells.

Water-Soluble Near-Infrared Fluorescent Probes for Specific Detection of Monoamine Oxidase A in Living Biosystems.

Monoamine oxidase (MAO) has two isomers (A and B), and the analysis of each one in biological samples is of great potential in studying MAO-related diseases. However, specific detection and imaging of MAO-A in cells and in vivo are still a great challenge at present due to the relative lack of suitable near-infrared (NIR) fluorescent probes. In this work, two new NIR fluorescent probes, Rma-1 and Rma-2, have been developed for the analysis of MAO-A in living biosystems. The probes were designed by conjugating the specific structure of the MAO-A inhibitor to hemicyanine (an NIR fluorophore) directly or through a self-immolative linker. Both probes are water-soluble and showed selective and sensitive NIR (708 nm) responses toward MAO-A rather than MAO-B, of which probe Rma-1 with a self-immolative linker exhibited superior analytical performance with a detection limit of 4.5 ng/mL and 13-fold specificity for MAO-A over MAO-B. Further, probe Rma-1 has been successfully utilized to image the MAO-A activity in cells, zebrafish, and tumor-bearing mice, showing a promising prospect for MAO-A study in carcinoma.

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.

A fluorescent probe for specific detection of β-galactosidase in living cells and tissues based on ESIPT mechanism

β-galactosidase is of great significance to living organisms, which is an important marker of primary ovarian cancer and cellular senescence. To detect the activity of β-galactosidase, a novel fluorescent probe ESIPT-GAL which based on excited state intramolecular proton transfer (ESIPT) mechanism for detecting β-galactosidase is developed in this work with low background fluorescence and high sensitivity (ΦF = 0.0045–0.2409). The fluorescence intensity at 552 nm of this probe increased by ~ 55 times with β-galactosidase addition (0–4 U/mL), and its detection limit is very low (3.9 × 10−5 U/mL). In addition, the spectral data (pseudo-first-order rate: 1.303 min−1) and enzyme kinetic parameter (Vmax = 69.5 μΜ•S−1) both show that the probe can achieve rapid response to β-galactosidase. Moreover, the probe has good water solubility, which ensures that it has good biocompatibility and can be easily applied to detect β-galactosidase in living cells and tissues. Importantly, the probe ESIPT-GAL can monitor β-galactosidase in deep mouse tissue sections (90 μm).

A novel ratiometric AIE-based fluorescent probe for specific detection of Hcy/Cys and imaging of living cells in vivo

The sensing mechanism toward Hcy/Cys is realized based on the condensation reaction, which breaks CN to form a thiazolidine adduct.

A rational design of fluorescent probes for specific detection and imaging of endogenous formaldehyde in living cells

Formaldehyde (FA) plays important roles in many physiological processes and closely relates to human health. However, the specific detection of FA remains a great challenge. Herein, we report a rational strategy for specific detection and imaging of FA through combining characteristic structure of a fluorophore merged with the modified ortho-phenylenediamine as a recognition moiety. After the reaction of FA and the propyl-modified ortho-phenylenediamine, the probe NP1 and NP2 based on naphthalimide fluorophore exhibited the turn-on fluorescence response for the detection of FA. In particular, the probe NP2 with the greater steric hindrance presented superior specificity for imaging the endogenous FA in living cells. This work may serve as a general strategy to design specific recognition moieties for FA probes.

A fluorescent probe for specific detection of cysteine in lysosomes via dual-color mode imaging.

Biothiols, as part of the reactive sulfur species (RSS), are a class of bioactive molecules that play important physiological roles in human body. However, due to the similarity in structure and reaction sites of biothiols, it is difficult to differentiated detection them at the same time. In this work, a fluorescent probe CM-NBD combined coumarin derivative and 7-nitrobenzofurazan has been developed, which can effectively detect biothiols through simple ether cleavage. Because of a specific location group, CM-NBD can well localize in lysosomes with a high co-localization coefficient. Interesting, due to the weakly acidic environment of lysosomes, Cys can be distinguished from Hcy/GSH and H2S via dual-color mode. The probe is able not only to image exogenous biothiols but also to discriminate Cys from Hcy/GSH and H2S in cells and zebrafish model.

A novel ratiometric fluorescent probe for specific detection of HSO3- at nanomolar level through 1, 4-Michael addition

A Fluorescence Resonance Energy Transfer (FRET)-based ratiometric fluorescent probe, Cy-p-Np, was reported for specificial detection of HSO3− over anions and other Reactive Sulfur Species (RSS). In free probe, naphthalimide was selected as the donor while hemicyanine acted as the acceptor and the recognition unit for HSO3−. The probe Cy-p-Np displayed a ratiometric fluorescent response (I527/I590) to HSO3− with response time (150s) and limit detection (98.1 nM) based on the nucleophilic attack of HSO3− toward electrically positive hemicyanine. The proposed mechanism of nucleophilic HSO3−-promoted 1, 4-Michael addition reaction was proved by HRMS. The low toxicity allowed probe Cy-p-Np to be applied to detect exogenous HSO3− in living cells successfully. All the outstanding properties of probe Cy-p-Np provided the potential for the further application in live detection and even deeper biological applications.