Dual-response Fluorescent Probe Research Articles

A dual-response fluorescent probe for Al3+ and Zn2+ in aqueous medium based on benzothiazole and its application in living cells

A new benzothiazole-based fluorescent chemosensor (BZDM), namely 2-amino-3-(((E)-3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzylidene)amino)maleonitrile, has been designed and synthesized for detection of Al3+/Zn2+ in aqueous medium. The sensing behavior displayed that BZDM possessed an excellent selectivity towards Al3+/Zn2+ with a distinct fluorescence enhancement in DMSO/Tris-HCl buffer solution. The binding stoichiometry was determined to be 1: 1 between BZDM and Al3+/Zn2+ according to Job’s plot method and NMR analysis. The sensing of Al3+/Zn2+ was almost free from interference of other relevant metal ions. Under optimal conditions, the LOD value for Al3+ and Zn2+ was found to be 7.06 μM and 2.98 μM, separately. Notably, the probe was found to have good biological compatibility and was employed to detect Al3+/Zn2+ in living Hela cells.

A novel dual-responsive fluorescent probe for the detection of copper(II) and nickel(II) based on BODIPY derivatives

A novel dual-responsive fluorescence probe 6 was constructed by introducing a dipicolyamine moiety on the BODIPY-based skeleton via Sonogashira coupling reaction and confirmed by 1H NMR, 13C NMR, elemental analysis and high-resolution mass spectroscopy (HRMS). The present probe 6 exhibited high selectivity and sensitivity toward Cu2+ and Ni2+ detection over other competitive metal ions by fluorescence quenching phenomena, respectively. In addition, the detection limits (DLs) for Cu2+ and Ni2+ were calculated to be as low as both 0.1 μM respectively, which were lower than the maximum allowable level of the World Health Organization (WHO) limit for the drinking water. The stoichiometric ratio of the probe 6 toward the Cu2+ or Ni2+ ions was determined to be 1:1 according to the result of the Job's plot and HRMS analysis. These results indicated that probe 6 can be used as a selective ‘‘turn-off’’ fluorescent sensor for the detection of Cu2+ and Ni2+.

A dual-response fluorescent probe for detection and bioimaging of hydrazine and cyanide with different fluorescence signals

Due to favourable efficiency and low cost, dual-response fluorescent probes play critical roles in the development of fluorescence assay system. Herein, a novel dual-response fluorescent probe (RDCN) was designed and synthesized for the detection of two environmental contaminants: hydrazine (N2H4) and cyanide (CN−). Probe RDCN exhibited discriminative sensing behaviors to N2H4 and CN− with different reaction mechanisms, allowing the high selectivity and sensitivity detection for N2H4 and CN−. The probe itself displayed red-emitting fluorescence as a result of strong intramolecular charge transfer (ICT) between diethylamino and dicyano. After mixing with hydrazine, a new corresponding hydrazone came into being with an intense yellow fluorescence. While, the probe could also largely switch to blue fluorescence in response to CN−. Furthermore, the probe RDCN was successfully employed to determine N2H4 and CN− in water samples with the detection limits of 0.08 μM and 0.33 μM, and to visualize N2H4 and CN− in live cells by means of different fluorescence channels (blue and yellow channels), revealing that probe RDCN has potential applications for discriminative detection N2H4 and CN− in biological environment.

A novel dual-response fluorescent probe based on nopinone for discriminative detection of hydrazine and bisulfate from different emission channels

A novel fluorescent probe 4-(4′-(2-cyano-3-ethoxy-3-oxoprop-1-en-1-yl)- [1,1′-biphenyl]-4-yl)-2,2-difluoro-7,7-dimethyl-5,6,7,8-tetrahydro-2H-6,8-methanobenzo[d][1,3,2]dioxaborinin-1-ium-2-uide (CEFN) had been designed and developed for discriminative detection of N2H4 and HSO3− with two different sets of colorimetric and ratiometric fluorescence signals. The novel dual-response fluorescent probe CEFN can discriminative detect N2H4 and HSO3− with high selectivity, good sensitivity and fast response time. The response behaviors of probe CEFN for N2H4 and HSO3− were ascribed to different sensing mechanisms, which were investigated in detail by 1H NMR, HRMS spectra. Furthermore, the probe CEFN could be served as a novel method for tracking N2H4 and HSO3− in living cells.

Dual-Response Detection of Oxidized Glutathione, Ascorbic Acid, and Cell Imaging Based on pH/Redox Dual-Sensitive Fluorescent Carbon Dots.

The pH/redox dual-sensitive fluorescent carbon dots (pHRCDs) with the fluorescence quantum yield of 16.97% were synthesized by the pyrolysis of l-glutamic acid (l-glu) and dopamine (DA). Compared with the quantum dot (QD)–dopamine conjugate, when the pH value of the solution was changed from neutral to alkaline, the pHRCDs exhibited unique optical phenomenon including red-shift of fluorescence peak and the fluorescence intensity first decreasing from pH 7 to 10 and then increasing from pH 10 to 13. The pHRCDs could be developed for a discriminative and highly sensitive dual-response fluorescent probe for the detection of oxidized glutathione (GSSG) and ascorbic acid (AA) activity in human blood. Under the optimized experimental conditions, the dual-response fluorescent probe can detect GSSG and AA in the linear range of 1.2–3.6 and 27–35 μM with the detection limits of 0.1 and 3.1 μM, respectively. In addition, the pHRCDs demonstrated low cytotoxicity and good biocompatibility, which can be well applied to in vitro cell imaging, and the pHRCDs/GSH fluorescence system has been successfully developed for the detection of AA in real samples.

Step-wise functionalization of polysiloxane towards a versatile dual-response fluorescent probe and elastomer for the detection of H2S in two-photon and NO in near-infrared modes.

Simultaneous detection of gasotransmitters such as NO and H2S is a crucial task to investigate the complicated relationship between NO and H2S. In this work, we presented a new approach to construct a dual response fluorescent probe for NO/H2S by step-wise functionalization of polysiloxanes. A near-infrared (NIR) and two-photon (TP) fluorescent probe, P-CYN, was fabricated for respectively visualizing H2S and NO in vivo. This work presented a powerful tool for the investigation of the relationship between gasotransmitters, and provided a valid strategy for further design of dual-response fluorescent probes.

1,8-Naphthalimide-based dual-response fluorescent probe for highly discriminating detection of cys and H2S

Hydrogen sulfide (H2S) and cysteine (Cys) are ubiquitous biological thiols in physiological and pathological processes of living systems. Their aberrant concentration levels are associated with many diseases. Hence, we developed a water-soluble fluorescent (FL) probe for H2S and Cys response. The probe was synthesized by two steps of reaction coupling between a triethylene glycol naphthalimide dye and 7-chlorobenzofurazan-4-sulfonyl chloride (CBD) dye linked by a rigid piperazine group. The probe displayed dual fluorescence emission for Cys (λem = 571 nm) and H2S (λem = 535 nm) detection, accompanied by different absorbance changes for Cys (λex = 405 nm) and H2S (λex = 486 nm). The probe could distinguish Cys and H2S from other biological thiols (GSH, Hcy) with longer wavelength or stronger fluorescence emission. Moreover, the probe was allowed to sense the exogenous or endogenous H2S and Cys with dual-emission signal (blue and red channel) in living MCF-7 cells.

A dual-responsive fluorescent probe for detection of fluoride ion and hydrazine based on test strips.

Hydrazine (N2H4) and fluoride ion (F-) are regarded as environmental pollutants and potential carcinogens. A dual-functional fluorescent probe (probe 1) was developed for both F- and N2H4 with high selectivity and sensitivity. 1 was based on nucleophilic aromatic substitution reaction for N2H4 detection and selective cleavage of 4-nitrobenzenesulphonyl group for the determination of F-. The limits of detection of probe for F- and N2H4 were 77.82 nM and 29.34 nM, respectively, which are far below the threshold limit value (TLV) of United States Environmental Protection Agency (EPA). The home-made test strips of 1 provided the positive tool for F- and gaseous N2H4 in different system. And the confocal fluorescence images indicated that 1 can quantitatively detect N2H4 in living PC12 cells. Promisingly, 1 has great prospects for N2H4 imaging and determining in living system.

A dual-response fluorescent probe for the discrimination of cysteine from glutathione and homocysteine

A highly selective and sensitive turn-on fluorescent BODIPY-based probe for the simultaneous and selective detection of Cys and Hcy/GSH from dual emission channels was developed. The spatial steric hindrance of the methyl groups at 1- and 7-positions in BODIPY skeleton prevented intramolecular displacement of sulfur with amino group of Hcy but not of Cys. GSH molecular skeleton is larger and amino is far away from sulfydryl group, and the product of the reaction of probe with GSH canstay in thiol phase. Therefore, the probe was successfully applied to the detection of Cys from GSH/Hcy. The confocal microscopy experiments implied that this probe is a promising candidate for imaging of Cys and Hcy/GSH in Hela cells.

A Dual-Response Fluorescent Probe for the Detection of Viscosity and H2S and Its Application in Studying Their Cross-Talk Influence in Mitochondria.

Intracellular viscosity is an essential microenvironmental parameter and H2S is a critical gaseous signaling molecule, which are both related to various physiological processes. It is reported that the change of viscosity and an imbalance of H2S production in the mitochondria are both associated with overexpression of amyloid betapeptide (Aβ), which is thought to play a central role in the pathogenesis of Alzheimer's disease (AD). However, to our best knowledge, no fluorescent probe is found for dual detection of mitochondrial viscosity and H2S. Herein, a dual-response fluorescent probe (Mito-VS) is designed and synthesized to monitor the level of viscosity and H2S, respectively. Mito-VS itself is nonfluorescent due to a free intramolecular rotation between dimethylaniline and pyridine. After the increase of viscosity, the rotation is prohibited and an intense red fluorescence is released. Upon the addition of H2S, the probe can react with H2S to form compound 3 and a strong green fluorescence can be observed. Moreover, the probe possesses a good mitochondrion-targeting ability and is applied for imaging the change of viscosity on the red channel and visualizing the variation of exogenous and endogenous H2S concentration on the green channel in mitochondria. Most importantly, the probe is capable of studying the cross-talk influence of viscosity and H2S in mitochondria, which is very beneficial for knowing the pathogenesis of AD.

Dual-responsive fluorescent probe for hypochlorite via pH-modulated, ring-opening reactions of a coumarin-fused rhodol derivative

Hypochlorite plays crucial roles in various human activities and is involved in many diseases. Therefore, facile and accurate detection of hypochlorite is imperative. In the current study, a coumarin-fused rhodol derivative (CR-Ts) with a sulfonohydrazide hypochlorite recognition unit was synthesized and validated for its ability to detect hypochlorite in real samples. Both the related intermediate, CR, and CR-Ts were fully characterized, including their X-ray crystal structures. Unlike previously reported methods, the CR-Ts probe, which is based on the unique, pH-modulated, ring-opening reactions of the coumarin-rhodol hybrid, displayed selective, dual-fluorescent turn-on responses to hypochlorite without interferences from many metal ions and other reactive oxygen/nitrogen species. In acidic media, only the five-membered spiro-ring opened, which resulted in an obvious color change and fluorescence enhancement, and both the five-membered spiro-ring and six-membered lactone ring opened under alkaline conditions to exhibit another color change and more intense fluorescence. The reaction mechanism was also investigated via a pKa study and was confirmed by mass spectrometry. The limit of detection (LOD) for hypochlorite in alkaline conditions (21.53 nM) is approximately four times more sensitive than that in acidic media (88.01 nM). The proposed method was successfully used to detect the hypochlorite concentration in tap water and commercial disinfectants, and consistent results with low discrepancies were obtained.

A novel dual-ratiometric-response fluorescent probe for SO2/ClO− detection in cells and in vivo and its application in exploring the dichotomous role of SO2 under the ClO− induced oxidative stress

Intracellular reactive sulfur species and reactive oxygen species play vital roles in immunologic mechanism. As an emerging signal transmitter, SO2 can be generated as the anti-oxidant, while SO2 is also a potential oxidative stress-inducer in organism. Aiming to elucidate in-depth the dichotomous role of SO2 under oxidative stress, we designed a dual-response fluorescent probe that enabled the respective or successive detection of SO2 and ClO-. The probe itself emits the red fluorescence (625nm) which can largely switch to blue (410nm) and green fluorescence (500nm) respectively in response to SO2 and ClO-, allowing the highly selective and accurate ratiometric quantification for both SO2 and ClO- in cells. Moreover the ultrafast (SO2: <60s; ClO-: within sec) and highly sensitive (detection limits: SO2: 3.5nM; ClO-: 12.5nM) detection were achieved. With the robust applicability, the developed probe was successfully used to quantify SO2 and endogenous ClO- in respectively the HeLa cells and the RAW 264.7cells, as well as to visualize the dynamic of SO2/ClO- in zebrafish. The fluorescent imaging studies and flow cytometry analysis confirmed the burst-and-depletion and meanwhile the oxidative-and-antioxidative effects of intracellular SO2 under the NaClO induced oxidative stress.

A dual-response quinoline-based fluorescent sensor for the detection of Copper (II) and Iron(III) ions in aqueous medium

A new and dual-response fluorescent probe (QLBM) based on quinoline and benzimidazole groups has been designed and developed for recognition of copper(II) ion (Cu2+) and iron(III) ion (Fe3+) simultaneously. This sensor displays a favorable selectivity for Cu2+ and Fe3+ ions over a range of other common metal cations in 100% aqueous medium (50mM Tris buffer, pH 7.2), leading to prominent fluorescence on-off. The detection limits were 1.35×10−7M for Cu2+ and 1.24×10−7M for Fe3+ respectively. This dual-response fluorescent probe for Cu2+ and Fe3+ was distinguished by further reduction of the ascorbic acid. It is reported for the first time to use ascorbic acid to discriminate Cu2+ and Fe3+ by fluorescent probe technology. The recognizing mechanism of QLBM toward Cu2+ and Fe3+ has been investigated in detail by NMR, HR-MS and density functional theory (DFT) calculations. Moreover, further application of the sensor in fluorescence imaging was studied in HeLa cells due to the low cytotoxicity and good photophysical properties, suggesting that QLBM could be used as a fluorescent sensor for tracking Cu2+ and Fe3+ in cells.

A dual-response fluorescent probe for Zn2+ and Al3+ detection in aqueous media: pH-dependent selectivity and practical application

A Schiff base-type fluorescent probe (1) consist of 2-hydroxynaphthaldehyde and glutamide moieties has been designed and synthesized for detection Zn2+ and Al3+. The probe shows pH dependent dual-selectivity for Zn2+ and Al3+ in Tris-HCl buffer, viz. that can selectively recognized Zn2+ at pH 7.4 and Al3+ at pH 6.0, respectively. From Job's plots and MS data, the stoichiometric ratios of the probe with Zn2+ and Al3+ appeared to be 1:1 and 2:1, respectively. The probe can detect as low as 5.5 × 10−8 M−1 Zn2+ and 1.27 × 10−7 M−1 Al3+, whereas respective association constants are 4.27 × 104 M−1 and 3.50 × 109 M−1. Furthermore, it is also confirmed that the probe has good cell-permeability and could thus be used to selectively sense intracellular Zn2+ and Al3+ by bioimaging in different pH environment. Finally the probe has been used successfully for determination of the analytes in real drug samples.

Correction: A dual stimuli responsive fluorescent probe carrier from a double hydrophilic block copolymer capped with β-cyclodextrin

Correction for ‘A dual stimuli responsive fluorescent probe carrier from a double hydrophilic block copolymer capped with β-cyclodextrin’ by Guang Yang et al., Polym. Chem., 2015, 6, 3382–3386.

A dual stimuli responsive fluorescent probe carrier from a double hydrophilic block copolymer capped with β-cyclodextrin

A β-cyclodextrin terminated triblock copolymer with both hydrophilic temperature and pH sensitive segments was prepared and characterized in terms of self-assembling and encapsulation behaviors.

A 1,3‐Indandione‐Functionalized Tetraphenylethene: Aggregation‐Induced Emission, Solvatochromism, Mechanochromism, and Potential Application as a Multiresponsive Fluorescent Probe

A tetraphenylethene (TPE) derivative substituted with the electron-acceptor 1,3-indandione (IND) group was designed and prepared. The targeted IND-TPE reserves the intrinsic aggregation-induced emission (AIE) property of the TPE moiety. Meanwhile, owing to the decorated IND moiety, IND-TPE demonstrates intramolecular charge-transfer process and pronounced solvatochromic behavior. When the solvent is changed from apolar toluene to highly polar acetonitrile, the emission peak redshifts from 543 to 597 nm. IND-TPE solid samples show an evident mechanochromic process. Grinding of the as-prepared powder sample induces a redshift of emission from green (peak at 515 nm) to orange (peak at 570 nm). The mechanochromic process is reversible in multiple grinding-thermal annealing and grinding-solvent-fuming cycles, and the emission of the solid sample switches between orange (ground) and yellow (thermal/solvent-fuming-treated) colors. The mechanochromism is ascribed to the phase transition between amorphous and crystalline states. IND-TPE undergoes a hydrolysis reaction in basic aqueous solution, thus the red-orange emission can be quenched by OH(-) or other species that can induce the generation of sufficient OH(-). Accordingly, IND-TPE has been used to discriminatively detect arginine and lysine from other amino acids, due to their basic nature. The experimental data are satisfactory. Moreover, the hydrolyzation product of IND-TPE is weakly emissive in the resultant mixture but becomes highly blue-emissive after the illumination for a period by UV light. Thus IND-TPE can be used as a dual-responsive fluorescent probe, which may extend the application of TPE-based molecular probes in chemical and biological categories.