Fluorescence Detection Of Fe3 Research Articles

A highly selective and sensitive peptide-based probe for the colorimetric and fluorescent detection of Fe3+, Al3+ and Cr3+ and its application in living cells imaging

A new colorimetric and fluorescent dual-responsive probe named Rb-SSC was designed and synthesized using Rhodamine B and tripeptide (SerSerCys-NH2) as raw reactants. The selective recognition properties in detecting 17 metal ions were investigated by UV–Vis spectroscopy and fluorescence spectroscopy in DMF/water (4:6, v/v, 10.0 mM HEPES, pH = 7.4), and the results showed that Rb-SSC had high selectivity fluorescence response and clear colorimetric analysis for trivalent metal ions (Fe3+, Al3+ and Cr3+). These selectivity were attributed to protonation of Rb-SSC, and the Ksp value of the trivalent ions promotes the formation of hydrolyzed H+. Additionally, the limit of detections (LODs) were found to be 27.4 nM for Fe3+, 28 nM for Al3+ and 62.3 nM for Cr3+, respectively. In addition, MTT assay and cells experiments showed that Rb-SSC has low toxicity and achieved fluorescence imaging of trivalent metal ions in living cells. What's more, the G/B ratio has a good linear relationship with the concentrations of Fe3+ based on the smartphone sensing platform (RGB values), and the limit of detection (LOD) was as low as 0.37 μM.

Red Emission Carbon Dots Prepared by 1,4-Diaminonaphthalene for Light-Emitting Diode Application and Metal Ion Detection.

Carbon dots (CDs), as the most important type of carbon materials, have been widely used in many fields because of their unique fluorescence characteristics and excellent properties of biocompatibility. In previous studies, the fluorescence of CDs was mainly concentrated in the blue and green, whereas the red fluorescence was relatively less. Herein, we prepared efficient red-emitting CDs from 1,4-diaminonaphthalene using solvothermal methods. We discussed the effects of different solvothermal solvents on CDs. The results show that CDs prepared with octane and acetone as reaction media have the best fluorescence properties. The CDs dispersed in different organic solvents exhibited tunable emission across a wide spectrum from 427 nm to 679 nm. We further demonstrated the application of red light-emitting diode (LED) optoelectronics and fluorescence detection of Fe3+ in aqueous solution.

A chiral carbazole based sensor for sequential “on-off-on” fluorescence detection of Fe3+ and tryptophan/histidine

Quantitative analysis of the L-tryptophan content in commercial products by chemosensor has not been reported yet. In this study, the chiral carbazole based sensor (CCS), bearing a chiral “urea-carboxylic acid” binding site was prepared. CCS was proved to be effective in the consecutive detection of Fe3+, L-tryptophan (Trp), and L-histidine (His) by naked eyes. CCS exhibits different color changes and fluorescent ‘turn-off’ response toward Fe3+ and Fe2+. The discrimination of these two oxidation states of iron by CCS is important to understand the iron-related biological reactions. The limit of detection for Fe3+ by CCS is 84 nM in a high water-content solution (99 % water). CCS sensor can act as a reversible fluorescence quenching sensor for Fe3+. The results of Job’s plot analysis and mass spectra reveal that Fe3+ binds to CCS with a 1:1 stoichiometry. The CCS-Fe3+ complex can sense tryptophan, or histidine by a dose-dependent turn-on fluorescent response in a high water-content solution (99 % water). The mass spectra suggest the sensing of L-histidine or L-tryptophan by CCS-Fe3+ was performed with a CCS-Fe3+: amino acid binding ratio of 1:1. In comparison with other chemosensors reported in the literature, CCS can detect the L-Trp and L-His with a low limit of detection (0.31 μM L-Trp, 7.64 μM L-His) in a high water content environment. Furthermore, the CCS - Fe3+ complex based chemosensor was successfully applied to quantify the L-tryptophan content in commercial sleep-improving capsules containing various ingredients. The measured L-tryptophan contents in two samples are close to the announced values.

A New Zn(II) Complex: Fluorescent Detection of Fe3+ Ions in Water and Prevention Effect on DVT By Regulating Platelets Numbers and Activity of Clotting Factor.

[Zn(dima)(H2O)0.5]·H2O (1), a three-dimensional metal organic framework (MOF) with high porosity was formed by self-assembly of 4,6-di(1h-imidazol-1-yl)isophthalic acid (H2dima) and Zn2+ ion. Owning to its excellent luminescence and excellent water stability, complex 1 can be used as a super sensitive sensor to detect Fe3+ ions via the behaviors of fluorescence quenching. At the same time, the mechanism for the fluorescence quenching is also further discussed. Furthermore, the prevention effect of the compound on the deep vein thrombosis of the lower extremities (DVT) after lower venous CHIVA surgery was evaluated in vivo. Firstly, the DVT animal models was constructed and the number of platelets was measured with flow cytometry and content of clotting factor IX and anticoagulant factor III was also detected with Lowry method after compound treatment. The molecular docking simulation results indicate that the Zn(II) complex has activity to protein docking pocket with different sizes.

Novel rhodamine probe for colorimetric and fluorescent detection of Fe3+ ions in aqueous media with cellular imaging.

A novel rhodamine-pyridine conjugated spectroscopic probe RhP was synthesized and its X-ray single crystalline properties were revealed with tabulation. The RhP displayed a distinct pale-pink colorimetric and "turn-on" fluorescent response to Fe3+ in aqueous media [H2O:DMSO (95:5, v/v)] than that of other interfering ions. During the Fe3+ recognition, the absorption (UV-Vis) and photoluminescence (PL) spectral studies revealed new peaks at 561 and 592nm, respectively. The 1:1 stoichiometry and binding sites were verified by Job's plot, ESI-mass, and 1H NMR titrations. Subsequently, LOD and binding constant for RhP+Fe3+ complex were estimated as 102.3nM and 6.265×104M-1 from linear fitting and Benesi-Hildebrand plots, correspondingly. Sensor reversibility of RhP+Fe3+ by EDTA was demonstrated by UV/PL and TRPL investigations. Moreover, the photoinduced energy transfer mechanism and band gap changes were established from the DFT interrogations. Lastly, cellular imaging studies were carried out to authenticate the real applicability of RhP in Fe3+ detection.

Fluorescence detection of Fe3+ ion using ultra-small fluorescent carbon dots derived from pineapple (Ananas comosus): Development of miniaturized analytical method

Herein, water soluble nanosize carbon dots (CDs) were derived from pineapple (Ananas comosus) via acid-oxidation method using sulphuric and phosphoric acids as oxidizing agents. The synthesized CDs showed three fluorescence colors i.e., blue (B-CDs), green (G-CDs) and, yellow (Y-CDs) under UV-lamp. Spectroscopic techniques (fluorescence, UV–visible and Fourier-transform infrared) were used for the investigation of surface chemistry of three CDs and their analytical applications. The three different fluorescent CDs probes were subjected to metal ions selectivity study where the fluorescence of B-CDs was significantly quenched by one of the metal ion i.e., Fe3+, which indicates that the formation of Fe3+ ion - B-CDs complex. The rapid fluorescence quenching occurs when Fe3+ ion is added. The fluorescence quenching exhibited a linear response for Fe3+ ion (0.05–500 μM) and a detection limit of 0.03 μM. The B-CDs-based fluorescence “turn-off” method may open up a facile and sensitive analytical approach for fluorescence assay of Fe3+ ion in biofluids and environmental matrices.

A diarylethene derived Fe3+ fluorescent chemosensor and its application in wastewater analysis

A diarylethylene derivative containing an acylhydrazone Schiff base moiety was designed and synthesized. Upon alternative irradiation with UV and visible lights, the compound showed distinct fluorescence switching properties based on fluorescence resonance energy transfer mechanism. On the other hand, the fluorescence can be efficiently quenched by 69 fold in the presence of Fe3+ ion in methanol. As a Fe3+ fluorescent chemosensor, the sensing mechanism, the influence of pH on sensing properties, and the practical application were also studied. In the complex, the breaking of the intramolecular H-bonding between the –CO NH– proton and the oxygen at the C O of lactone, the weaking of electrons transfer, and the paramagnetic nature of Fe3+ induced a consequent decrease fluorescence. The compound was found to be stable in a wide range of pH and a highly efficient Fe3+ ion quencher with a detection limit of 4.6 × 10−6 mol L−1. Moreover, the fluorescent detection of Fe3+ was demonstrated by filter paper strips. A series of test papers with different Fe3+ concentrations were prepared and used as the standard card. The analytical application of measuring Fe3+ concentration in wastewater samples were evaluated by comparison with the standard card directly and quickly.

A cystine-based dual chemosensor for fluorescent-colorimetric detection of CN- and fluorescent detection of Fe3+ in aqueous media: Synthesis, spectroscopic, and DFT studies.

A new dual-responsive chiral cystine based chemosensor, Cys(cou)2, has been designed and characterized by 1H NMR, 13C NMR, FT-IR, UV-vis as well as elemental analysis. This sensor exhibited an excellent response towards Fe3+ and CN- with high selectivity and sensitivity by fluorescence turn-off mechanism. The binding mode of Cys(cou)2 with Fe3+, and CN- was confirmed by ESI-MS, 1H NMR, and fluorescence titration and also quantum chemical calculation. These results showed that the stoichiometric ratio of Cys(cou)2-Fe3+ and Cys(cou)2-CN is 1:1 and 1:3 in DMSO/Tris aqueous buffer (1:1, v/v), respectively. The linear relationship of the Stern-Volmer plot illustrates the static quenching mechanism at different concentrations. The detection limit (LOD) and binding constant (Ka) for Fe3+ and CN- are 0.029 μM, 1.28 × 104 and 0.51 μM, 9.94 × 106, respectively. Moreover, Cys(cou)2 can act as a colorimetric sensor for CN- in DMSO with the color change from colorless to yellow.

Benzothiazole-based fluorescence chemosensors for rapid recognition and “turn-off” fluorescence detection of Fe3+ ions in aqueous solution and in living cells

Two new benzothiazole-based fluorescence sensors (sensor 1 and sensor 2) have been successfully synthesized and their structures have been well characterized by 1H NMR, 13C NMR and mass spectrometry. Sensor 1 and sensor 2 displayed a selective fluorescence quenching response towards Fe3+ ions in aqueous solutions with good anti-interference ability. Sensor 1 and sensor 2 exhibited lower detection limits for Fe3+, 8.43 μM for sensor 1 and 5.86 μM for sensor 2, respectively. The Job's plot, mass spectrometry, 1H NMR titration and DFT calculations proved that sensors formed 1:1 complexes with Fe3+ ions. In addition, sensor 1 and Sensor 2 had low cell toxicity and could be used to monitor the existence of Fe3+ ions in living cells.

Dual-mode colorimetric and fluorometric probe for ferric ion detection using N-doped carbon dots prepared via hydrothermal synthesis followed by microwave irradiation

Dual-mode colorimetry and fluorescence detection methods have gained more attentions in recent years. In this paper, a colorimetric and fluorescent dual-mode probe was constructed based on N-doped carbon dots (CDs) that was synthesized using hydrothermal heating followed by microwave irradiation. The CDs were purified using a polarity-based method followed by a size-based method. The CDs selectively form a purple-colored complex with Fe3+ ions accompanied by quenching of the fluorescence emission. The fluorescence emission of CDs was not affected by common metal cations and anions, but was only complexed and quenched by Fe3+ ions. Cyclic voltammetry and optical spectroscopy were used to measure the HUMO and LUMO levels of the CDs. The fluorescence quenching is due to the transfer of the photo-induced electrons from the excited state of the CDs to the LUMO of Fe3+ ions. The fluorescence lifetime of CDs in the presence and absence of Fe3+ was examined by time-correlated single-photon counting. These results along with changes in the absorption spectra suggest a static fluorescence quenching mechanism. The CDs were used as a dual-readout probe for the colorimetric and fluorescent detection of Fe3+ ions in real samples. The lower limit of detection obtained using colorimetry was 0.5 μM (S/N = 3), while that obtained using fluorimetry was 50 nM. The fluorescence intensity of the CDs is pH independent between 2 and 9, which increases the working range for practical application. Furthermore, the CDs in aqueous solution are photostable, thermostable, and stable under high ionic strength, which makes the probe robust and rugged.

Ultrasensitive fluorescence detection of Fe3+ ions using fluorescein isothiocyanate functionalized Ag/SiO2/SiO2 core–shell nanocomposites

Fluorescein isothiocyanate (FITC) functionalized Ag/SiO2/SiO2 core–shell (CS) nanoparticles (NPs) and nanorods (NRs) are synthesized by chemical method to perform the fluorescence detection of Fe3+ in aqueous medium. The Fe3+ ion sensing is performed on the basis of metal-enhanced fluorescence and subsequent fluorescence quenching of fluorophore (fluorescein isothiocyanate) in aqueous medium. The intensity of fluorescence of FITC is found to get enhanced with increasing the silica shell thickness. The fluorescence intensity of FITC of spherical Ag/SiO2/SiO2 (FITC) CS NPs (AgSiF50) is amplified up to 2.25-folds whereas, in case of Ag/SiO2/SiO2 (FITC) CS NRs (AgSiFNR), the fluorescence intensity of FITC is amplified up to 3.63-folds compared to that of pure FITC. Owing to the amplified fluorescence of FITC, AgSiF50 and AgSiFNR samples are evaluated for detection of Fe3+ in an aqueous medium and the proposed nanoprobes exhibit good sensitivity towards Fe3+ detection because of strong binding affinity of Fe3+ with isothiocyanate group of FITC. The limit of detections for AgSiF50 and AgSiFNR are found to be 19.4 nM and 0.8 nM, respectively. The BET surface areas of AgSiF50 and AgSiFNR are calculated to be 157.64 m2 g−1 and 193.42 m2 g−1, respectively. The higher sensitivity of AgSiFNR compared to AgSiF50 for Fe3+ ion sensing is accredited to the higher adsorption capacity and higher fluorescence of FITC. This Ag/SiO2/SiO2 (FITC) CS NRs probe is a very simple and efficient sensor for Fe3+ ion detection and thus, using this sample, a very simple Arduino based electronic device is fabricated which can give real-time application of the idea.

Nitrogen-doped carbon dots with high quantum yield for colorimetric and fluorometric detection of ferric ions and in a fluorescent ink.

Nitrogen-doped carbon dots (N-CDs) with a quantum yield of 41 ± 3% and excellent stability were prepared and are shown to be viable probes for the determination of ferric ions, which is a strong quencher of fluorescence. The absorption peak of the N-CDs is located at325nm. The optimal excitation and emission wavelengths of the N-CDs are 340nm and 430nm, respectively. The fluorometric response to Fe(III) is linear in the ranges between 1.0 and 21.0μM and between 0.05 and 30.0μM, and the limits of detection are 0.28μM in case of colorimetry and 13.5nM in case of fluorometry. Quenching by Fe(III) is mainly attributed to a combination of chelation (static quenching) and inner filter effect. The N-CDs also can be used as a new sort of fluorescent ink owing to the strong luminous performance and chemical inertness. Graphic abstract The illustration for synthesis of the N-CDs and its applications for colorimetric and fluorescent detection of Fe3+ and fluorescent ink.

Fluorescent detection of Fe3+ ions in living cells by novel NaTb(SO4)2•H2O nanospheres

Fluorescent detection of Fe3+ ions in living cells by novel NaTb(SO4)2•H2O nanospheres

A pyrene-based dual chemosensor for colorimetric detection of Cu2+ and fluorescent detection of Fe3+

A pyrene based chemosensor was designed and synthesized. The pyrene fluorophore was connected with a pyridine unit through a Schiff base structure to give the sensor (L). L was tested with a variety of metal ions and exhibited high colorimetric selectivities for Cu2+ and Fe3+ over other ions. Upon binding with Cu2+ or Fe3+, L showed an obvious optical color change from colorless to pink for Cu2+ or orange for Fe3+ over a wide pH range from 3 to 12. Moreover, the fluorescence of L at 370nm decreased sharply after bonding with Fe3+, while other metal ions including Cu2+ had no apparent interference. Thus, using such single chemosensor, Cu2+ and Fe3+ can be detected independently with high selectivity and sensitivity. The limits of detection toward Cu2+ and Fe3+ were 8.5 and 2.0μM, respectively. DFT calculation results also proved the formation of stable coordination complexes and the phenomenon of fluorescence quenching by Fe3+. Furthermore, L was also successfully used as a bioimaging reagent for detection of Fe3+ in living cells.

A rhodamine-based “turn-on” fluorescent probe for Fe3+ in aqueous solution and its application in bioimaging

A novel colorimetric and off–on fluorescent chemosensor which contained a strong electron-withdrawing group was synthesized. As expected, the chemosensor exhibited high selectivity and excellent sensitivity in both absorbance and fluorescence detection of Fe3+ (Θ (CH3OH, H2O) = 3/7, 1 mM Tris–HCl buffer, pH = 7.40). Upon addition of Fe3+, the solution of the chemosensor resulted in a color change from colorless to obvious pink. These significant changes in color could be used for naked-eye detection. Furthermore, fluorescence imaging experiments of Fe3+ ions in living MGC-803 cells demonstrated its value of practical applications in biological systems.

Fluorescence detection of Fe3+ ions in aqueous solution and living cells based on a high selectivity and sensitivity chemosensor

Although ferric ion (Fe3+) performs critical roles in diverse biochemical processes in living systems, its physiological and pathophysiological functions have not been fully explored due to the lack of methods for quantification of Fe3+ ions in biological system. In this work, a highly sensitive and selective fluorescence chemosensor, L, was developed for the detection of Fe3+ ions in aqueous solution and in living cells. L was facile synthesized by one step reaction and well characterized by NMR, API-ES, FT-IR, and elementary analysis. The prepared chemosensor displayed excellent selectivity for Fe3+ ions detection over a wide range of tested metal ions. In the present of Fe3+ ions, the strong green fluorescence of L was substantially quenched. The 1:1 stoichiometry of the complexation was confirmed by a Job’s plot. The association constant (Ka) of L with Fe3+ was evaluated using the Benesi–Hildebrand method and was found to be 1.36×104M−1. The MTT assay determined that L exhibits low cytotoxicity toward living cells. Confocal imaging and flow cytometry studies showed that L is readily interiorized by MDA-MB-231 cells through an energy-dependent pathway and could be used to detect of Fe3+ ions in living cells.

A rhodamine-based sensor for chromogenic detection of Cu2+ and fluorescent detection of Fe3+

A rhodamine-benzimidazole conjugate (RB) as a probe was investigated. UV-Vis analysis showed that a strong absorption band at 552 nm was formed with the addition of Cu2+, while other transition metal ions induced a little more absorption. The absorption value of RB solution at 552 nm has a linear correlation with Cu2+ concentration between 35–70 μmol/L; the detection limit reached 6.82×10−2 μmol/L, which is lower than the settled limitation for copper in the drinking water (∼30 μmol/L) standardized by World Health Organization (WHO). Moreover, FL analysis showed that only Fe3+ could induce large fluorescence intensity enhancement at 582 nm; other common metal ions including Cu2+ cannot induce the enhancement. There was a good linear correlation between relative fluorescence intensity and Fe3+ concentration ranging from 2 μmol/L to 20 μmol/L, and the detection limit reached 1.70×10−2 μmol/L. The results showed that RB could detect Cu2+ and Fe3+ simultaneously, with the UV-Vis and fluorescence spectroscopy, respectively.

A ratiometric fluorescent probe for iron(III) and its application for detection of iron(III) in human blood serum

A simple and versatile ratiometric fluorescent Fe3+ detecting system, probe 1, was rationally developed based on the Fe3+-mediated deprotection of acetal reaction. Notably, this reaction was firstly employed to design fluorescent Fe3+ probe. Upon treatment with Fe3+, probe 1 showed ratiometric response, with the fluorescence spectra displaying significant red shift (up to 132nm) and the emission ratio value (I522/I390) exhibiting approximately 2362-fold enhancement. In addition, the probe is highly sensitive (with the detection limit of 0.12μM) and highly selective to Fe3+ over other biologically relevant metal ions. The sensing reaction product of the probe with Fe3+ was confirmed by NMR spectra and mass spectrometry. TD-DFT calculation has demonstrated that the ratiometric response of probe 1 to Fe3+ is due to the regulation of intramolecular charge transfer (ICT) efficiency. Moreover, the practical utility in fluorescence detection of Fe3+ in human blood serum was also conducted, and probe 1 represents the first ratiometric fluorescent probe that can be used to monitor Fe3+ level in human blood serum. Finally, probe 1 was further employed in living cell imaging with pancreatic cancer cells, in which it displayed low cytotoxicity, satisfactory cell permeability, and selective ratiometric response to Fe3+.

A GBI@PPyNWs-based prototype of reusable fluorescence sensor for the detection of Fe3+ in aqueous solution

Polypyrrole nanowires (PPyNWs) anchored with 2-guanidinobenzimidazole (GBI) molecules (denoted as GBI@PPyNWs) have been achieved via porous anodic aluminum oxide (AAO) template-assisted approach, and used for sensitive and selective rapid fluorescence detection of Fe3+ based on the formation of coordination compound between GBI and Fe3+. The fluorescence intensity of the GBI@PPyNWs increases linearly with [Fe3+] ranging from 10−5 to 1.4 × 10−4 M in water solution, while in ethanol/water solution it linearly decreases with [Fe3+] ranging from 2 × 10−6 to 3.8 × 10−5 M, both with good selectivity. The GBI@PPyNWs were used to detect Fe3+ in blood serum solution successfully. Moreover, the GBI@PPyNWs are reusable. Our new conceptual design, using the assembly of two biocompatible materials of PPy and GBI, for the detection of Fe3+ in aqueous solution, has potential in biological detection and may open a door to the design of effective fluorescence probes for other metal ions.

Single sensor for multiple analytes: chromogenic detection of I− and fluorescent detection of Fe3+

A novel receptor, designed with a combination of oxygen and nitrogen-binding sites for metal ions and hydrogen bond donor sites for anion binding, was synthesized. The receptor has been explored for the selective detection of I − against a range of physiologically relevant anions and cations through changes in its UV–vis spectra. On the other hand, receptor-binding selectivity for Fe 3+ over a wide linear concentration range was observed through changes in the emission spectra. This is the first Letter of a sensor capable of detecting both I − and Fe 3+ using two different detection modes.