42 results on '"Tooba Hallaj"'
Search Results
2. A sensitive homogeneous enzyme assay for euchromatic histone-lysine-N-methyltransferase 2 (G9a) based on terbium-to-quantum dot time-resolved FRET
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Mohammad Amjadi, Tooba Hallaj, and Niko Hildebrandt
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enzyme assay ,histone-modifying enzymes ,epigenetic enzymes ,time-resolved fret ,inhibitor screening ,Medicine (General) ,R5-920 ,Biology (General) ,QH301-705.5 - Abstract
Introduction: Histone modifying enzymes include several classes of enzymes that are responsible for various post-translational modifications of histones such as methylation and acetylation. They are important epigenetic factors, which may involve several diseases and so their assay, as well as screening of their inhibitors, are of great importance. Herein, a bioassay based on terbium-to-quantum dot (Tb-to-QD) time-resolved Förster resonance energy transfer (TR-FRET) was developed for monitoring the activity of G9a, the euchromatic histone-lysine N-methyltransferase 2. Overexpression of G9a has been reported in some cancers such as ovarian carcinoma, lung cancer, multiple myeloma and brain cancer. Thus, inhibition of this enzyme is important for therapeutic purposes. Methods: In this assay, a biotinylated peptide was used as a G9a substrate in conjugation with streptavidin-coated ZnS/CdSe QD as FRET acceptor, and an anti-mark antibody labeled with Tb as a donor. Time-resolved fluorescence was used for measuring FRET ratios. Results: We examined three QDs, with emission wavelengths of 605, 655 and 705 nm, as FRET acceptors and investigated FRET efficiency between the Tb complex and each of them. Since the maximum FRET efficiency was obtained for Tb to QD705 (more than 50%), this pair was exploited for designing the enzyme assay. We showed that the method has excellent sensitivity and selectivity for the determination of G9a at concentrations as low as 20 pM. Furthermore, the designed assay was applied for screening of an enzyme inhibitor, S-(5’-Adenosyl)-L-homocysteine (SAH). Conclusion: It was shown that Tb-to-QD FRET is an outstanding platform for developing a homogenous assay for the G9a enzyme and its inhibitors. The obtained results confirmed that this assay was quite sensitive and could be used in the field of inhibitor screening.
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- 2021
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3. Terbium Sensitized Chemiluminescence Method for the Determination of Rabeprazole -Application to Pharmaceutical Analysis and Dissolution Studies
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Mohammad Amjadi, Jamshid Manzoori, and Tooba Hallaj
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Sensitized chemiluminescence ,Terbium(III) ,Cerium(IV)-Sulfite ,Rabeprazole ,Dissolution study ,Human plasma ,Analytical chemistry ,QD71-142 - Abstract
A simple and sensitive chemiluminescence-based method was established for the determination of rabeprazole.The proposed method was based on the enhancing effect of rabeprazole on Ce(IV)-Na2SO3 -Tb(III) chemiluminescence reaction. A possible mechanism was discussed for chemiluminescence system by studying UV-Vis, fluorescence and chemiluminescence spectra. The effects of various chemical parameters were investigated and optimized. Under the optimum conditions, the enhanced chemiluminescence intensity was directly proportional to the concentration of rabeprazole in the range of 0.015-0.2 µg ml-1, with a detection limit of 6 ng ml-1. The proposed method was applied to the analysis of pharmaceutical formulations and human plasma samples and to the dissolution study of rabeprazole tablets with satisfactory results. The results indicated that more than 95% of the labeled amount of rabeprazole was dissolved over 30 min in the basic medium, while only 10% of rabeprazole was released in acidic medium.
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- 2015
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4. Sulfur quantum dots as a novel platform to design a sensitive chemiluminescence probe and its application for Pb 2+ detection
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Sima Mojarrad, Abdolhossein Naseri, and Tooba Hallaj
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Chemistry (miscellaneous) ,Biophysics - Published
- 2022
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5. Nitrogen and copper-doped saffron-based carbon dots: Synthesis, characterization, and cytotoxic effects on human colorectal cancer cells
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Mohadeseh Nemati, Tooba Hallaj, Jafar Rezaie, and Yousef Rasmi
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General Medicine ,General Pharmacology, Toxicology and Pharmaceutics ,General Biochemistry, Genetics and Molecular Biology - Published
- 2023
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6. A turn off-on fluorometric and paper-based colorimetric dual-mode sensor for isoniazid detection
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Neda Azizi, Tooba Hallaj, and Naser Samadi
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Detection limit ,Materials science ,Isoniazid ,Biophysics ,Dual mode ,Paper based ,Fluorescence ,Carbon ,Turn off ,Cobalt oxyhydroxide ,Chemistry (miscellaneous) ,Quantum Dots ,medicine ,Colorimetry ,Fluorometry ,Naked eye ,medicine.drug ,Nuclear chemistry - Abstract
In the present study, cobalt oxyhydroxide (CoOOH) nanosheets were applied for establishing a dual fluorometric and smartphone-paper-based colorimetric method to detect isoniazid. CoOOH nanosheets quenched the fluorescence emission of sulfur and nitrogen co-doped carbon dots (S,N-CDs) due to inner filter effect (IFE). The quenched fluorescence intensity of S,N-CDs restored in the presence of isoniazid due to destroying CoOOH nanosheets by this drug. Moreover, with adding isoniazid the solution color of CoOOH nanosheets altered from brownish yellow to pale yellow. We exploited these facts to design a turn off-on fluorometric and paper-based colorimetric sensor for isoniazid measurement at the range 0.5-5 and 5-100 μM with detection limits of 0.28 μM and 4.0 μM, respectively. The introduced dual sensor was used for pharmaceutical, environmental and biological analysis of isoniazid with satisfactory results. The paper-based colorimetric sensor can be applied for isoniazid portable monitoring using a smartphone as a detector or even the naked eye.
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- 2021
7. Microwave-assisted facile synthesis of N, P co-doped fluorescent carbon dot probe for the determination of nifedipine
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Tooba Hallaj, Saeedeh Narimani, and Naser Samadi
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Carbon dot ,Nifedipine ,Chemistry ,Fluorescence ,Microwave assisted ,Carbon ,Analytical Chemistry ,Quantum Dots ,medicine ,Humans ,Microwaves ,Co doped ,medicine.drug ,Nuclear chemistry ,Fluorescent Dyes - Abstract
A simple and fast microwave synthesis method was applied for the preparation of several carbon dots (CDs) from various combinations of urea, phosphoric acid, and B-alanine as nitrogen, phosphorus, and carbon precursors. The maximum quantum yield (44%) was obtained for nitrogen and phosphorus co-doped carbon dots (N, P-CDs) prepared from urea, B-alanine, and phosphoric acid. Furthermore, N, P-CDs were exploited to synthesize a simple and sensitive fluorometric probe to determine nifedipine (NFD). We determined that the analytical response of the designed sensor could be affected by the kind of dopant and synthesis precursors. It is worth mentioning that the fluorescence intensity of N, P-CDs was weakened by NFD, and no fluorescence quenching was observed for other prepared CDs. The NFD-developed sensor demonstrated a linear response range of 3.3 × 10
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- 2021
8. Morphology transition of Ag nanoprisms as a platform to design a dual sensor for NADH sensitive assay
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Tooba Hallaj, Rana Salari, and Mohammad Amjadi
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General Chemical Engineering ,General Physics and Astronomy ,General Chemistry - Published
- 2022
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9. Plasmon-enhanced fluorimetric and colorimetric dual sensor based on fluorescein/Ag nanoprisms for sensitive determination of mancozeb
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Tooba Hallaj, Mohammad Amjadi, and Afrooz Zandi
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Zineb ,Chromatography ,Silver ,Chemistry ,Metal Nanoparticles ,Wavelength shift ,General Medicine ,Fluorescence ,Analytical Chemistry ,Dual sensor ,Fluorescence intensity ,chemistry.chemical_compound ,Maneb ,Fruit juice ,Mancozeb ,Colorimetry ,Fluorescein ,Fluorometry ,Plasmon ,Food Science - Abstract
A plasmon-enhanced fluorimetric and colorimetric dual sensor was designed to detect mancozeb based on fluorescein (as a fluorimetric reporter) and AgNPRs (as a fluorescence enhancer and colorimetric reporter). The sensing mechanism was based on the shape transformation of AgNPRs due to etching and anti-etching effect of S2O32− and mancozeb. We observed that AgNPRs enhanced the fluorescence intensity of fluorescein around 4-fold. By adding S2O32−, the AgNPR florescence enhancement effect decreased, also SPR peak of AgNPRs blue-shifted and the solution color altered from blue to purple. The fluorescein fluorescence intensity and AgNPR’s SPR peak position restored in the presence of mancozeb due to its protecting effect on AgNPRs. The restored fluorescence intensity and the SPR wavelength shift were proportional to the mancozeb concentration at the range of 0.005–0.1 and 0.005–0.075 mg/L, respectively. The developed sensor was successfully applied to measure mancozeb in fruit juice samples.
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- 2021
10. A sensitive turn-off-on fluorometric sensor based on S,N co-doped carbon dots for environmental analysis of Hg(II) ion
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Zahra Abolghasemi-Fakhri, Tooba Hallaj, and Mohammad Amjadi
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Materials science ,Silver ,Biophysics ,Analytical chemistry ,chemistry.chemical_element ,Metal Nanoparticles ,02 engineering and technology ,01 natural sciences ,Ion ,Quantum Dots ,Fourier transform infrared spectroscopy ,Spectroscopy ,Detection limit ,Quenching ,010401 analytical chemistry ,Mercury ,021001 nanoscience & nanotechnology ,Fluorescence ,Carbon ,0104 chemical sciences ,Spectrometry, Fluorescence ,chemistry ,Chemistry (miscellaneous) ,Transmission electron microscopy ,0210 nano-technology - Abstract
A simple and sensitive fluorescence turn-off-on sensor was established by means of S,N co-doped carbon dots (S,N-CDs) and Ag nanoparticles (AgNPs) for the determination of Hg2+ . For this purpose, blue emissive S,N-CDs were hydrothermally synthesized and characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. We observed that the fluorescence intensity of the as-prepared S,N-CDs was impressively quenched by AgNPs. The quenching mechanism was studied and attributed to nanosurface energy transfer and the inner filter effect between S,N-CDs and AgNPs. Furthermore, by adding Hg2+ , the fluorescence intensity of S,N-CDs/AgNPs was restored as a result of aggregation of AgNPs in the presence of Hg2+ . Based on these facts, S,N-CDs and AgNPs were exploited to design a sensitive turn-off-on sensor for analysis of Hg2+ . The recovered fluorescence signal was proportional to the concentration of Hg2+ in the range 1.5-2000 nM with a detection limit of 0.51 nM. The established sensor was used with satisfactory results for measurement of Hg2+ in environmental water samples.
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- 2021
11. Terbium–To–Quantum Dot Förster Resonance Energy Transfer for Homogeneous and Sensitive Detection of Histone Methyltransferase Activity
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Kimihiro Susumu, Xue Qiu, Tooba Hallaj, Igor L. Medintz, Niko Hildebrandt, Mohammad Amjadi, Urmia University, University of Tabriz [Tabriz], Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Naval Research Laboratory (NRL), Chimie Organique et Bioorganique : Réactivité et Analyse (COBRA), Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie Organique Fine (IRCOF), Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Organique Fine (IRCOF), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and ANR-16-CE09-0015,NEUTRINOS,Suivi des interactions biologiques par détection optique ultrasensible à base de nanoparticules(2016)
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Streptavidin ,Histone methyltransferase activity ,[SDV]Life Sciences [q-bio] ,Kinetics ,010402 general chemistry ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Histone H3 ,Quantum Dots ,Fluorescence Resonance Energy Transfer ,[CHIM]Chemical Sciences ,General Materials Science ,Enzyme kinetics ,Terbium ,030304 developmental biology ,[PHYS]Physics [physics] ,0303 health sciences ,Combinatorial chemistry ,0104 chemical sciences ,3. Good health ,Förster resonance energy transfer ,chemistry ,Histone methyltransferase ,Histone Methyltransferases ,Biosensor - Abstract
International audience; The development of rapid, simple, and versatile biosensors for monitoring the activity of histone modifying enzymes (HMEs) is needed for the improvement of diagnostic assays, screening of HME inhibitors, and a better understanding of HME kinetics in different environments. Nanoparticles can play an important role in this regard by improving or complementing currently available enzyme detection technologies. Here, we present the development and application of a homogeneous methyltransferase (SET7/9) assay based on time-gated Förster resonance energy transfer (TG-FRET) between terbium complexes (Tb) and luminescent semiconductor quantum dots (QDs). Specific binding of a Tb-antibody conjugate to a SET7/9-methylated Lys4 on a histone H3(1–21) peptide substrate attached to the QD surface resulted in efficient FRET and provided the mechanism for monitoring the SET7/9 activity. Two common peptide-QD attachment strategies (biotin–streptavidin and polyhistidine-mediated self-assembly), two different QD colors (625 and 705 nm), and enzyme sensing with post- or pre-assembled QD–peptide conjugates demonstrated the broad applicability of this assay design. Limits of detection in the low picomolar concentration range, high selectivity tested against non-specific antibodies, enzymes, and co-factors, determination of the inhibition constants of the SET7/9 inhibitors SAH and (R)-PFI-2, and analysis of the co-factor (SAM) concentration-dependent enzyme kinetics of SET7/9 which followed the Michaelis–Menten model highlighted the excellent performance of this TG-FRET HME activity assay.
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- 2020
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12. A sensitive plasmonic probe based on in situ growth of a Ag shell on a Au@N-CD nanocomposite for detection of isoniazid in environmental and biological samples
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Tooba Hallaj and Mohammad Amjadi
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Detection limit ,Nanocomposite ,Analytical chemistry ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Dielectric ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Catalysis ,0104 chemical sciences ,Ion ,chemistry ,Materials Chemistry ,Surface plasmon resonance ,0210 nano-technology ,Carbon ,Plasmon - Abstract
In this study, a new plasmonic probe based on the wavelength shift of the surface plasmon resonance band of a Au@N-CD nanocomposite was introduced for determination of isoniazid. The Au@N-CD nanocomposite was synthesized using a simple method by using N-doped carbon dots (N-CDs) as a reducing and stabilizing agent. When isoniazid is added to a mixture of Au@N-CD nanocomposite and Ag+ ions, it reduces Ag+ to Ag0 on the surface of the Au@N-CDs to produce Au@N-CDs@AgNP core–shell nanoparticles. As a result, the dielectric environment around the Au@N-CDs is altered and their SPR peak shifts to shorter wavelengths. Based on this principle, a probe was designed for isoniazid detection in the range of 0.1 to 2.0 μM with a detection limit (3 s) of 0.06 μM. The method was applied for determination of isoniazid in biological and environmental samples with satisfactory results.
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- 2019
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13. Energy transfer with nanoparticles for in vitro diagnostics
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Niko Hildebrandt, Jiajia Guo, Jingyue Xu, Tooba Hallaj, Laura Francés-Soriano, Xue Qiu, Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Urmia University, Chimie Organique et Bioorganique : Réactivité et Analyse (COBRA), Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie Organique Fine (IRCOF), Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Organique Fine (IRCOF), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
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[PHYS]Physics [physics] ,Materials science ,[SDV]Life Sciences [q-bio] ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Chromophore ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Acceptor ,Small molecule ,Fluorescence ,0104 chemical sciences ,Förster resonance energy transfer ,Colloidal gold ,[CHIM]Chemical Sciences ,0210 nano-technology ,Luminescence ,ComputingMilieux_MISCELLANEOUS - Abstract
In vitro diagnostics is an important application for nanoparticles in the life sciences and has attracted continuous research interest. While nanoparticles can be used as single luminescent probes, their unique photophysical properties provide many more advantages when they are combined with other nanoparticles or molecules to form energy transfer pairs. Energy transfer-based assays are homogeneous in nature and are often as simple as “mix and measure,” which has catalyzed their frequent use in clinical diagnostics. Most bioanalytical applications involve Forster resonance energy transfer (FRET), a distance-dependent nonradiative energy transfer from a donor to acceptor chromophore through dipole–dipole interaction. Nanosurface energy transfer (NSET) describes energy transfer to metal nanoparticles. Semiconductor quantum dots, upconversion nanoparticles, gold nanoparticles, and carbon dots are among the most applied nanoparticles in in vitro diagnostics and they have been largely explored in the analysis of disease-related nucleic acids, proteins, and small molecules. The utilizations of various nanoparticles with their intrinsic optical properties have changed the diagnostic horizon substantially by improving the assay simplicity, sensitivity, selectivity, robustness, and multiplexing capacity. In this chapter, we discuss the use of nanoparticles in energy transfer assays for in vitro diagnostics and show their strong potential for advancing the field beyond molecular fluorescent probes.
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- 2020
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14. A chemiluminescence reaction consisting of manganese(IV), sodium sulfite, and sulfur- and nitrogen-doped carbon quantum dots, and its application for the determination of oxytetracycline
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Tooba Hallaj, Fatemeh Mirbirang, and Mohammad Amjadi
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Nitrogen ,chemistry.chemical_element ,Food Contamination ,Oxytetracycline ,02 engineering and technology ,Manganese ,01 natural sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,Limit of Detection ,law ,Quantum Dots ,Animals ,Sulfites ,Colloids ,Fourier transform infrared spectroscopy ,Spectroscopy ,Sodium sulfite ,Chemiluminescence ,Detection limit ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,Sulfur ,Carbon ,0104 chemical sciences ,Milk ,Manganese Compounds ,chemistry ,Luminescent Measurements ,0210 nano-technology ,Luminescence ,Nuclear chemistry - Abstract
Sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) were prepared by a solid-phase hydrothermal method from cysteine and citric acid and characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR spectroscopy. These QDs were exploited as enhancers to amplify the chemiluminescence (CL) of manganese(IV)-sodium sulfite reaction. S,N-CQDs exceptionally enhanced the CL intensity of this system, around 900-fold. This effect was attributed to the energy transfer from SO2*, produced by reaction of Mn(IV) with SO32−, to S,N-CQDs. The maximum wavelength of CL emission was 480 nm, which confirmed that the final emitting species was S,N-CQDs. After optimization of reaction conditions, the analytical applicability of S,N-CQD-Mn(IV)-SO32− CL system was studied. In the presence of oxytetracycline, the CL intensity was significantly diminished. A linear relationship was observed between CL signal and the logarithm of oxytetracycline concentration in the range of 0.075–3.0 μM with a detection limit of 25 nM. This CL assay for oxytetracycline was used for analysis of spiked milk and water samples.
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- 2020
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15. A highly sensitive plasmonic sensor for detection of selenium based on the shape transformation of silver nanoprisms
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Tooba Hallaj, Mohammad Amjadi, and Rana Salari
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Detection limit ,Materials science ,Absorption spectroscopy ,010401 analytical chemistry ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Ion ,Wavelength ,chemistry ,Etching (microfabrication) ,Transmission electron microscopy ,Materials Chemistry ,Electrical and Electronic Engineering ,0210 nano-technology ,Instrumentation ,Selenium ,Plasmon - Abstract
We report on a plasmonic probe for detection of ultra-trace amounts of Se(IV) based on morphological transformation of silver nanoprisms (AgNPRs). AgNPRs were synthesized in a mild condition and characterized by UV–vis absorption spectroscopy and transmission electron microscopy (TEM). It was found that in the presence of Se(IV), SPR peak of AgNPRs at 720 nm shifts to lower wavelengths and the color of solution changes from light blue to violet. This is due to the shape transformation of AgNPRs to nanodisks which is proved by TEM images, and probably results from the etching of corners of NPRs by selenite ions. Based on this phenomenon, a sensitive colorimetric probe was developed for determination of Se(IV) in the concentration range of 2.5–100 μg L−1 with a detection limit of 1.2 μg L-1. The developed method was applied for analysis of water and food samples.
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- 2018
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16. An amplified chemiluminescence system based on Si-doped carbon dots for detection of catecholamines
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Tahmineh Shahbazsaghir, Jamshid L. Manzoori, Mohammad Amjadi, and Tooba Hallaj
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Silicon ,Inorganic chemistry ,Si doped ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Analytical Chemistry ,law.invention ,Surface-Active Agents ,chemistry.chemical_compound ,Catecholamines ,Magazine ,Pulmonary surfactant ,Limit of Detection ,Bromide ,law ,Humans ,Instrumentation ,Spectroscopy ,Chemiluminescence ,Detection limit ,Cetrimonium ,Chemistry ,010401 analytical chemistry ,Reproducibility of Results ,021001 nanoscience & nanotechnology ,Carbon ,Atomic and Molecular Physics, and Optics ,Nanostructures ,0104 chemical sciences ,Human plasma ,Luminescent Measurements ,Cetrimonium Compounds ,Linear Models ,0210 nano-technology - Abstract
We report on a chemiluminescence (CL) system based on simultaneous enhancing effect of Si-doped carbon dots (Si-CDs) and cetyltrimethylammonium bromide (CTAB) on HCO3−-H2O2 reaction. The possible CL mechanism is investigated and discussed. Excited-state Si-CDs was found to be the final emitting species, which are probably produced via electron and hole injection by oxy-radicals. The effect of several other heteroatom-doped CDs and undoped CDs was also investigated and compared with Si-CDs. Furthermore, it was found that catecholamines such as dopamine, adrenaline and noradrenaline remarkably diminish the CL intensity of Si-CD-HCO3−-H2O2-CTAB system. By taking advantage of this fact, a sensitive probe was designed for determination of dopamine, adrenaline and noradrenaline with a limit of detection of 0.07, 0.60 and 0.01 μM, respectively. The method was applied to the determination of catecholamines in human plasma samples.
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- 2018
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17. An enzyme-free fluorescent probe based on carbon dots – MnO2 nanosheets for determination of uric acid
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Zahra Kouhi, Mohammad Amjadi, and Tooba Hallaj
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Detection limit ,Quenching (fluorescence) ,General Chemical Engineering ,Inorganic chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nitrogen ,Sulfur ,Fluorescence ,Redox ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Uric acid ,0210 nano-technology ,Carbon - Abstract
A turn-on fluorescent probe based on the effect of MnO2 nanosheets on the fluorescence of sulfur and nitrogen co-doped carbon dots (S,N-CDs) is reported for detection of uric acid. MnO2 nanosheets have several interesting physicochemical properties such as high extinction coefficient and rich redox chemistry, which make them an excellent sensing platform. The fluorescence of S,N-CDs efficiently turns off in the presence of MnO2 nanosheets due to the inner filter effect as well as other quenching mechanisms. By adding uric acid to the solution of S,N-CDs–MnO2 nanosheets, the fluorescence of S,N-CDs is partially recovered as a result of its reaction with MnO2 nanosheets. Under the optimum conditions, the recovered fluorescence intensity displays a linear relationship with the concentration of uric acid in the range of 2.5–30 μM with a detection limit of 0.8 μM. The method was applied for analysis of biological samples with satisfactory results.
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- 2018
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18. A dual colorimetric and fluorometric sensor based on N, P-CDs and shape transformation of AgNPrs for the determination of 6-mercaptopurine
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Rana Salari and Tooba Hallaj
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Detection limit ,Silver ,Mercaptopurine ,Chemistry ,Analytical chemistry ,Shape transformation ,Phosphor ,Serum samples ,Fluorescence ,Carbon ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry ,Fluorescence intensity ,Etching (microfabrication) ,Quantum Dots ,Humans ,Colorimetry ,Fluorometry ,Surface plasmon resonance ,Instrumentation ,Spectroscopy - Abstract
In this study, we designed a dual colorimetric and fluorometric sensor by using nitrogen and phosphor doped carbon dots (N, P-CDs) and Ag nanoprisms (AgNPrs) to detect 6-mercaptopurine (6-MP). For this purpose, we applied the AgNPrs/I- mixture to establish a shape transformation based colorimetric method for the detection of 6-MP. The assay mechanism of colorimetric method was based on etching and protecting effect of I- and 6-MP on the AgNPrs. In the presence of I-, as an etching agent, the solution color altered from blue to purple and the position of AgNPrs' local surface plasmon resonance (LSPR) peak shifted to the blue wavelengths. This phenomenon was assigned to the morphological change of AgNPrs. In the presence of 6-MP, AgNPrs were protected from etching by I-, so the LSPR peak position and solution color of AgNPrs remained unchangeable. Furthermore, the fluorescence intensity of N, P-CDs decreased with adding AgNPrs/I- due to the spectral overlap between etched AgNPrs and N, P-CDs. The CDs' quenched fluorescence was restored in the presence of 6-MP, as a result of the protecting effect of 6-MP on the AgNPrs. These facts have been applied to develop a dual sensor for the determination of 6-MP at the range of 10–500 nM and 30–500 nM by colorimetric and fluorometric detection methods. The detection limits were obtained 10 and 4 nM for fluorometric and colorimetric methods, respectively. The developed sensor was utilized for dual signal analysis of 6-MP in human serum samples with satisfactory results.
- Published
- 2021
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- View/download PDF
19. A novel chemiluminescence sensor for the determination of indomethacin based on sulfur and nitrogen co‐doped carbon quantum dot–KMnO 4 reaction
- Author
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Tooba Hallaj, Jamshid L. Manzoori, Mohammad Amjadi, and Neda Azizi
- Subjects
Detection limit ,Calibration curve ,Biophysics ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Sulfur ,Nitrogen ,0104 chemical sciences ,law.invention ,chemistry ,Chemistry (miscellaneous) ,law ,Quantum dot ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Carbon ,Chemiluminescence - Abstract
We report on a simple and sensitive sulfur and nitrogen co-doped carbon quantum dot (S,N-CQD)-based chemiluminescence (CL) sensor for the determination of indomethacin. S,N-CQDs were prepared by a hydrothermal method and characterized by fluorescence spectra, Fourier transform infrared spectroscopy and transmission electron microscopy. To obtain the best CL system for determination of indomethacin, the reaction of S,N-CQDs with some common oxidants was studied. Among the tested systems, the S,N-CQD–KMnO4 reaction showed the highest sensitivity for the detection of indomethacin. Under optimum conditions, the calibration plot was linear over a concentration range of 0.1–1.5 mg L−1, with a limit of detection (3σ) of 65 μg L−1. The method was applied to the determination of indomethacin in environmental and biological samples with satisfactory results.
- Published
- 2017
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- View/download PDF
20. Application of the chemiluminescence system composed of silicon-doped carbon dots, iron(II) and K2S2O8 to the determination of norfloxacin
- Author
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Tooba Hallaj, Mohammad Amjadi, Jamshid L. Manzoori, and Tahmineh Shahbazsaghir
- Subjects
Detection limit ,Silicon ,Chemistry ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,law ,Transmission electron microscopy ,medicine ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Carbon ,Norfloxacin ,medicine.drug ,Chemiluminescence - Abstract
The authors describe a new chemiluminescence (CL) system composed of Si-doped carbon dots (Si-CDs), Fe(II) ions, and K2S2O8. The Si-CDs were prepared by a hydrothermal method and characterized by fluorescence spectra, transmission electron microscopy, energy-dispersive X-ray and FTIR spectroscopy. The weak CL of the Fe(II)-K2S2O8 reaction is found to be intensified by a factor of ~125 in the presence of Si-CDs. The possible mechanism for CL and its enhancement was studied by recording fluorescence and CL spectra and by investigating the effect of some radical scavengers. It is found that norfloxacin exerts a strong enhancing effect on the CL intensity of the system. This finding was employed to design a CL-based norfloxacin assay that works in the 5.0 to 300 μg L−1 concentration range, with a limit of detection (3 σ) of 1.5 μg L−1. The method was applied to the determination of therapeutic levels of norfloxacin in spiked human plasma and gave satisfactory results.
- Published
- 2017
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21. Sulfur and nitrogen co-doped carbon quantum dots as the chemiluminescence probe for detection of Cu2+ ions
- Author
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Tooba Hallaj, Mohammad Amjadi, Neda Azizi, and Jamshid L. Manzoori
- Subjects
inorganic chemicals ,Detection limit ,Metal ions in aqueous solution ,Inorganic chemistry ,Biophysics ,chemistry.chemical_element ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Fluorescence ,Copper ,Nitrogen ,Sulfur ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Ion ,law.invention ,chemistry ,law ,0210 nano-technology ,Chemiluminescence - Abstract
Herein, we investigated the direct chemiluminescence (CL) of sulfur and nitrogen co-doped carbon quantum dots (S,N-CQDs) induced by some common oxidants. The results showed that KMnO4 can produce much more intensive CL than other oxidants. The mechanism of the CL reaction was proposed based on the UV–vis, fluorescence and CL emission spectra. Moreover, the effect of some metal ions on the S,N-CQDs–KMnO4 CL system was studied and found that the CL intensity of this system was significantly declined by Cu2+ ions. Based on this effect, a simple and selective CL sensor was established for the detection of trace amount of Cu2+ in the concentration range of 0.01–0.5 mg L−1 with a limit of detection (3 s) of 2.1 µg L−1. The method was exploited for the determination of Cu2+ in human plasma and water samples with satisfactory results.
- Published
- 2017
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22. Doped-carbon dots: Recent advances in their biosensing, bioimaging and therapy applications
- Author
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Legha Ansari, Tooba Hallaj, Mohammad Amjadi, and Shahin Hallaj
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Diagnostic Imaging ,Materials science ,Multifunctional nanoparticles ,Photoacoustic imaging in biomedicine ,Nanotechnology ,Computed tomography ,02 engineering and technology ,01 natural sciences ,Colloid and Surface Chemistry ,Quantum Dots ,0103 physical sciences ,medicine ,Physical and Theoretical Chemistry ,010304 chemical physics ,Low toxicity ,medicine.diagnostic_test ,Doped carbon ,Surfaces and Interfaces ,General Medicine ,Photothermal therapy ,021001 nanoscience & nanotechnology ,Carbon ,Dual imaging ,Nanostructures ,Photochemotherapy ,0210 nano-technology ,human activities ,Biosensor ,Biotechnology - Abstract
As a fascinating class of fluorescent carbon dots (CDs), doped-CDs are now sparked intense research interest, particularly in the diverse fields of biomedical applications due to their unique advantages, including low toxicity, physicochemical, photostability, excellent biocompatibility, and so on. In this review, we have summarized the most recent developments in the literature regarding the employment of doped-CDs for pharmaceutical and medical applications, which are published over approximately the past five years. Accordingly, we discuss the toxicity and optical properties of these nanomaterials. Beyond the presentation of successful examples of the application of these multifunctional nanoparticles in photothermal therapy, photodynamic therapy, and antibacterial activity, we further highlight their application in the cellular labeling, dual imaging, and in vitro and in vivo bioimaging by use of fluorescent-, photoacoustic-, magnetic-, and computed tomography (CT)-imaging. The potency of doped-CDs was also described in the biosensing of ions, small molecules, and drugs in biological samples or inside the cells. Finally, the advantages, disadvantages, and common limitations of doped-CD technologies are reviewed, along with the future prospects in biomedical research. Therefore, this review provides a concise insight into the current developments and challenges in the field of doped-CDs, especially for biological and biomedical researchers.
- Published
- 2021
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23. A dual-mode colorimetric and fluorometric nanosensor for detection of uric acid based on N, P co-doped carbon dots and in-situ formation of Au/Ag core-shell nanoparticles
- Author
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Mohammad Amjadi, Tooba Hallaj, and Neda Azizi
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Detection limit ,010401 analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Nitrogen ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Nanosensor ,Urea ,Uric acid ,Surface plasmon resonance ,0210 nano-technology ,Citric acid ,Phosphoric acid ,Spectroscopy ,Nuclear chemistry - Abstract
Green emissive N,P co-doped carbon dots (N,P-CDs) were prepared by a simple hydrothermal method from citric acid, urea, and phosphoric acid as carbon, nitrogen and phosphorous pre-sources, respectively. The prepared N,P-CDs were applied to establish a dual-mode colorimetric and fluorometric sensor for monitoring - uric acid based on in-situ formation of Ag shell on the surface of AuNPs. We observed that the fluorescence intensity of N,P-CDs was quenched by adding AuNPs due to overlap between the emission peak of N,P-CDs and surface plasmon resonance peak (SPR) of AuNPs. With adding Ag+ and uric acid, the SPR peak intensity of AuNPs increased due to the reduction of Ag+ to Ag0 and Ag shell formation on the surface of AuNPs. Also, a blue shift in the SPR peak position of AuNPs was observed at the higher concentration of uric acid, resulting in the color variation of the solution from red to orange. These variations in the SPR peak intensity and position caused more fluorescence quenching of N,P-CDs because of the increasing spectral overlap between N,P-CDs and Au@AgNPs. We indicated that there is a logarithmic relationship between increasing SPR peak intensity of AuNPs as well as fluorescence quenching of N,P-CDs and uric acid concentration in the range of 0.1–10 and 0.5–10 μM, respectively. Regarding the mentioned facts, we developed a dual colorimetric and fluorometric sensor to determine uric acid. The detection limit was 40 and 400 μM for colorimetric and fluorometric methods, respectively. The established sensor was exploited for uric acid analysis in human urine samples.
- Published
- 2021
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24. Interaction of glucose-derived carbon quantum dots with silver and gold nanoparticles and its application for the fluorescence detection of 6-thioguanine
- Author
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Roghayeh Shokri, Tooba Hallaj, and Mohammad Amjadi
- Subjects
Detection limit ,Quenching (fluorescence) ,Materials science ,Biophysics ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,Fluorescence spectroscopy ,Silver nanoparticle ,0104 chemical sciences ,Chemistry (miscellaneous) ,Quantum dot ,Colloidal gold ,0210 nano-technology - Abstract
The interaction of glucose-derived carbon quantum dots (CQDs) with silver (Ag) and gold (Au) nanoparticles (NPs) was explored by fluorescence spectroscopy. Both metal NPs cause an efficient quenching of CQD fluorescence, which is likely due to the energy transfer process between CQDs as donors and metal NPs as acceptors. The Stern-Volmer plots were evaluated and corresponding quenching constants were found to be 1.9 × 1010 and 2.2 × 108 M-1 for AgNPs and AuNPs, respectively. The analytical applicability of these systems was demonstrated for turn-on fluorescence detection of the anti-cancer drug, 6-thioguanine. Because the CQD-AgNP system had much higher sensitivity than the CQD-AuNP system, we used it as a selective fluorescence probe in a turn-on assay of 6-thioguanine. Under optimum conditions, the calibration graph was linear from 0.03 to 1.0 μM with a detection limit of 0.01 μM. The developed method was applied to the analysis of human plasma samples with satisfactory results.
- Published
- 2016
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25. Dramatic enhancement effect of carbon quantum dots on the chemiluminescence of Ru(bpy)32+–Ce(IV) reaction and application to the determination of 4-nitrophenol
- Author
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Mohammad Amjadi and Tooba Hallaj
- Subjects
Detection limit ,Biophysics ,4-Nitrophenol ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microwave method ,Photochemistry ,01 natural sciences ,Biochemistry ,Fluorescence ,Atomic and Molecular Physics, and Optics ,Spectral line ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,chemistry ,Carbon quantum dots ,law ,0210 nano-technology ,Nuclear chemistry ,Chemiluminescence - Abstract
We studied the effect of glucose-derived carbon quantum dots (CQDs), prepared by a facile microwave method, on the R u ( b p y ) 3 2 + –Ce(IV) chemiluminescence (CL) reaction for the first time. It was found that the prepared CQDs enhance the CL intensity of this reaction by a factor of ~70. Possible mechanisms that lead to the effect were elucidated by recording the fluorescence and CL spectra. It was suggested that the phenomenon is probably due to the action of CQDs as reductive intermediates and also as accelerators of R u ( b p y ) 3 2 + and Ce(IV) reaction. It was also shown that 4-nitrophenol at even trace levels exerts a significant increasing effect on the R u ( b p y ) 3 2 + –Ce(IV)-CQDs CL system. This was exploited to design a new CL sensor for selective determination of 4-nirteophenol in the concentration range from 0.1 to 2.5 μM, with a limit of detection of 0.03 µM. 4-Nitrophenol was determined by this method in water and wastewater samples with satisfactory results.
- Published
- 2016
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26. S, N-doped carbon quantum dots enhanced Luminol-Mn(IV) chemiluminescence reaction for detection of uric acid in biological fluids
- Author
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Mohammad Amjadi, Tooba Hallaj, and Fatemeh Mirbirang
- Subjects
Detection limit ,010401 analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Luminol ,law.invention ,chemistry.chemical_compound ,chemistry ,Quantum dot ,law ,Transmission electron microscopy ,Uric acid ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Spectroscopy ,Chemiluminescence ,Nuclear chemistry - Abstract
Herein, S, N doped carbon quantum dots (S, N- CQDs) were prepared by a simple hydrothermal method and characterized by transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FTIR) analysis. The influence of as-prepared CQDs was studied on the luminol- Mn(IV) CL reaction. The results indicated that S,N-CQDs remarkably increase the CL intensity of this reaction (about 13 fold). Furthermore, it was found that the CL intensity of S,N-CQDs–luminol-Mn(IV) system was significantly declined by uric acid. We exploited the amplified CL system to design a novel probe for the detection of uric acid. The CL intensity of S,N-CQDs–luminol-Mn(IV) reaction was proportional to the logarithm of uric acid concentration in the range of 0.05 to 1.5 µM, with a limit of detection of 17 nM. Based on these results, a sensitive and straightforward CL method was developed for the analysis of uric acid in biological fluids with satisfactory results.
- Published
- 2020
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27. In situ formation of Ag/Au nanorods as a platform to design a non-aggregation colorimetric assay for uric acid detection in biological fluids
- Author
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Mohammad Amjadi, Tooba Hallaj, and Elham Nasirloo
- Subjects
Detection limit ,In situ ,010401 analytical chemistry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Colorimetric sensor ,chemistry ,Human plasma ,Biological fluids ,Uric acid ,Nanorod ,Surface plasmon resonance ,0210 nano-technology ,Spectroscopy ,Nuclear chemistry - Abstract
Herein, we report on a sensitive probe for colorimetric detection of uric acid based on the formation of Ag shell on Au nanorods (Ag/AuNRs) in the presence of uric acid. Uric acid can reduce Ag+ to Ag atoms which deposit on the surface of AuNRs and form Ag shell. As a result of this phenomenon, the dielectric environment around AuNRs changes and the longitudinal surface plasmon resonance (SPR) peak of AuNRs blue-shifts, leading to the change of solution color from purple to green. Based on these facts, a colorimetric sensor for the detection of uric acid in the concentration range of 0.1–1.0 µM with a detection limit of 0.065 µM was developed. The method was applied for analysis of uric acid in human plasma and urine samples with satisfactory results. The sensor can be used for uric acid detection even with bare eyes.
- Published
- 2020
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28. A sensitive colorimetric probe for detection of 6-thioguanine based on its protective effect on the silver nanoprisms
- Author
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Mohammad Amjadi, Rana Salari, and Tooba Hallaj
- Subjects
Silver ,Iodide ,Color ,02 engineering and technology ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Sensitivity and Specificity ,Analytical Chemistry ,Nanomaterials ,Etching (microfabrication) ,Limit of Detection ,Humans ,Surface plasmon resonance ,Thioguanine ,Instrumentation ,Spectroscopy ,6-Thioguanine ,chemistry.chemical_classification ,Detection limit ,Chemistry ,Hydrogen-Ion Concentration ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Nanostructures ,Human plasma ,Color changes ,Colorimetry ,0210 nano-technology - Abstract
In this work a non-aggregated colorimetric probe for detection of chemotherapeutic drug, 6–thioguanine (6-TG), is introduced. It is based on the protective effect of 6-TG on silver nanoprisms (AgNPRs) against the iodide-induced etching reaction. Iodide ions can attack the corners of AgNPRs and etch them, leading to the morphological transition from nanoprisms to nanodiscs. As a consequence, the solution color changes from blue to pink. However, in the presence of 6-TG, due to its protective effect on the corners of AgNPRs, I− ions cannot etch the prisms and the blue color of solution remains unchanged. Using this effect, selective sensor was designed for detection of 6–TG in the range of 2.5–500 μg L−1, with a detection limit of 0.95 μg L−1. Since with varying the concentration of 6-TG in this range, the color variation from pink to blue can be easily observed, the designed sensing scheme can be used as a colorimetric probe. The method was used for analysis of human plasma samples.
- Published
- 2018
29. Determination of 2,4-dichlorophenol in water samples using a chemiluminescence system consisting of graphene quantum dots, rhodamine B and cerium(IV) ion
- Author
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Mohammad Amjadi and Tooba Hallaj
- Subjects
Detection limit ,Chemistry ,Graphene ,Inorganic chemistry ,chemistry.chemical_element ,Nanochemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,Nanomaterials ,chemistry.chemical_compound ,Cerium ,law ,Quantum dot ,Rhodamine B ,0210 nano-technology ,Chemiluminescence - Abstract
We report that the presence of graphene quantum dots (GQDs) causes an ~60-fold enhancement of the chemiluminescence (CL) caused by the reaction between rhodamine B (RhB) and Ce(IV) ion. A possible CL mechanism is established on the basis of fluorescence, CL and UV-vis spectra. It is suggested that the GQDs facilitate the oxidation of RhB and accelerate the generation of the CL emitting species, thus leading to stronger CL intensity. We further observed that 2,4-dichlorophenol at even trace levels exerts a diminishing effect on this CL system. This finding was exploited to design a CL method for determination of 2,4-dichlorophenol in the 0.1 to 5.0 μM concentration range, with a detection limit of 25 nM. The method was applied to the analysis of spiked real water and wastewater samples and gave satisfactory results.
- Published
- 2016
- Full Text
- View/download PDF
30. Green synthesis of nitrogen-doped carbon dots from lentil and its application for colorimetric determination of thioridazine hydrochloride
- Author
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Masoumeh Aghdas Mayan, Tooba Hallaj, and Mohammad Amjadi
- Subjects
Detection limit ,Chromatography ,Chemistry ,General Chemical Engineering ,010401 analytical chemistry ,Nitrogen doped ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Serum samples ,01 natural sciences ,0104 chemical sciences ,Adsorption ,Thioridazine Hydrochloride ,0210 nano-technology ,Nitrogen source - Abstract
Herein, a simple and green hydrothermal method is introduced for the synthesis of nitrogen-doped carbon dots (N-CDs) by using lentils as both a carbon and a nitrogen source. The interaction of as-prepared N-CDs with AgNPs was utilized for the colorimetric detection of thioridazine hydrochloride. The yellow color of AgNPs changed to pale orange in the presence of N-CDs as a result of their adsorption on the surface of AgNPs. Furthermore, the addition of thioridazine hydrochloride to N-CD/AgNP mixture led to a change of the solution color to red. This unique behavior was exploited to design a sensitive colorimetric method for the determination of thioridazine hydrochloride in the concentration range of 5.0–150 μg L−1 with a detection limit of 3.0 μg L−1. The established method was applied to the determination of this drug in human serum samples.
- Published
- 2016
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- View/download PDF
31. A new turn-off fluorescence probe based on graphene quantum dots for detection of Au(III) ion
- Author
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Mohammad Amjadi, Tooba Hallaj, and Roghayeh Shokri
- Subjects
Metal ions in aqueous solution ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,Ion ,law.invention ,law ,Quantum Dots ,Graphite ,Instrumentation ,Spectroscopy ,Fluorescent Dyes ,Ions ,Detection limit ,Chemistry ,Carbonization ,Graphene ,021001 nanoscience & nanotechnology ,Fluorescence ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Spectrometry, Fluorescence ,Quantum dot ,Gold ,0210 nano-technology - Abstract
In this work, a new turn-off fluorescence probe based on the graphene quantum dots (GQDs) was designed for detection and quantification of Au(III) ion. GQDs were prepared by two simple carbonization methods using glucose (g-GQDs) and citric acid (c-GQDs) as carbon sources. The effect of some metal ions on the fluorescence intensity of the prepared GQDs was studied. It was found that the fluorescence of both GQDs is significantly quenched by Au(III) ions but the sensitivity and analytical performances are different for two prepared GQDs. Using g-GQDs, a new analytical method was developed for the determination of Au(III) in the concentration range of 1.0-80 μM, with a detection limit of 0.5 μM. The developed method was applied to the determination of Au(III) in water and plasma samples with satisfactory results.
- Published
- 2016
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- View/download PDF
32. A novel chemiluminescence method for determination of bisphenol Abased on the carbon dot-enhanced HCO3−–H2O2 system
- Author
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Mohammad Amjadi, Tooba Hallaj, and Jamshid L. Manzoori
- Subjects
Detection limit ,endocrine system ,Carbon dot ,Bisphenol A ,Baby bottle ,urogenital system ,Bisphenol ,Biophysics ,Analytical chemistry ,General Chemistry ,Condensed Matter Physics ,Biochemistry ,Fluorescence ,Atomic and Molecular Physics, and Optics ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Chemiluminescence ,Nuclear chemistry - Abstract
A simple and sensitive chemiluminescence (CL) method on the basis of carbon dot (C-dot) enhanced HCO 3 − –H2O2 system, is designed for the determination of bisphenol A (BPA). The very weak CL of the HCO 3 − –H2O2 system is enhanced by a factor of ~100 in the presence of C-dots. Possible mechanisms that lead to the effect were elucidated by recording fluorescence and CL spectra and studying the effect of some radical scavengers. This enhancement is inhibited by BPA in the concentration range from 1.0 to 100 µg L−1. This is exploited for its trace determination with a detection limit (3 s) of 0.3 µg L−1. The established method was applied to the determination of BPA in baby bottle and water samples with satisfactory results.
- Published
- 2015
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33. A sensitive chemiluminescence method for the determination of celecoxib in pharmaceutical and biological samples
- Author
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Jamshid L. Manzoori, Mohammad Amjadi, Tooba Hallaj, and Mohammad H. Sorouraddin
- Subjects
Detection limit ,Chromatography ,Nonsteroidal ,Fluorescence ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,Linear relationship ,chemistry ,law ,Celecoxib ,medicine ,Selectivity ,Sodium sulfite ,medicine.drug ,Chemiluminescence - Abstract
A simple and sensitive chemiluminometric method was developed for the determination of celecoxib, a nonsteroidal anti-inflammatory drug. It is based on the sensitization of Ce(IV)-Na2SO3 chemiluminescence reaction by celecoxib in the presence of Tb(III) ions. The mechanism of chemiluminescence reaction was studied by obtaining fluorescence and chemiluminescence spectra. The effects of various chemical parameters on chemiluminescence intensity were investigated and optimized. Under the optimum conditions, a linear relationship was obtained between the enhanced chemiluminescence intensity and the concentration of celecoxib in the range of 0.01–0.15 μg/mL, with a limit of detection of 2.5 ng/mL. Study of interferences confirmed the selectivity of the developed method for analysis of pharmaceutical and biological samples. The method was applied to the determination of celecoxib in pharmaceutical formulations and human plasma samples, and also to dissolution studies with satisfactory results.
- Published
- 2015
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34. Strong enhancement of the chemiluminescence of the Cu(II)-H2O2 system on addition of carbon nitride quantum dots, and its application to the detection of H2O2 and glucose
- Author
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Tooba Hallaj, Mohammad Amjadi, Zhenlun Song, and Robabeh Bagheri
- Subjects
Detection limit ,Chemistry ,Nanochemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,Fluorescence ,Spectral line ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,law ,Quantum dot ,0210 nano-technology ,Carbon nitride ,Chemiluminescence - Abstract
The authors report that carbon nitride quantum dots (CN QDs) exert a strong enhancing effect on the Cu(II)/H2O2 chemiluminescent system. Chemiluminescence (CL) intensity is enhanced by CN QDs by a factor of ~75, while other carbon nanomaterials have a much weaker effect. The possible mechanism of the effect was evaluated by recording fluorescence and CL spectra and by examining the effect of various radical scavengers. Emitting species was found to be excited-state CN QDs that produce green CL peaking at 515 nm. The new CL system was applied to the sensitive detection of H2O2 and glucose (via glucose oxidase-catalyzed formation of H2O2) with detection limits (3σ) of 10 nM for H2O2 and 100 nM for glucose. The probe was employed for glucose determination in human plasma samples with satisfactory results.
- Published
- 2017
- Full Text
- View/download PDF
35. Chemiluminescence of graphene quantum dots and its application to the determination of uric acid
- Author
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Jamshid L. Manzoori, Tooba Hallaj, and Mohammad Amjadi
- Subjects
Detection limit ,Graphene ,Chemistry ,Inorganic chemistry ,Biophysics ,Analytical chemistry ,General Chemistry ,Condensed Matter Physics ,Biochemistry ,Atomic and Molecular Physics, and Optics ,law.invention ,Nanomaterials ,symbols.namesake ,law ,Quantum dot ,symbols ,Emission spectrum ,Fourier transform infrared spectroscopy ,Raman spectroscopy ,Chemiluminescence - Abstract
We report on the chemiluminescence (CL) of graphene quantum dots (GQDs) induced by direct chemical oxidation. GQDs were prepared by a simple carbonization method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and Raman spectroscopy. It was found that Ce(IV) could oxidize GQDs to produce a relatively intense CL emission. The mechanism of CL generation was investigated based on the fluorescence and CL emission spectra. It was attributed to the radiative recombination of oxidant-injected holes and thermally excited electrons in the GQDs. In order to show the analytical application potential of GQDs-Ce(IV) CL system, it was applied to the determination of uric acid. Under the optimized conditions, the proposed CL system exhibited excellent analytical performance for determination of uric acid in the range of 1.0×10 −6 M–5.0×10 −4 M with a limit of detection of 5.0×10 −7 M. The method was applied to the determination of uric acid in human plasma and urine samples, with satisfactory results.
- Published
- 2014
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36. Direct chemiluminescence of carbon dots induced by potassium ferricyanide and its analytical application
- Author
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Tooba Hallaj, Mohammad Amjadi, Mohammad H. Sorouraddin, and Jamshid L. Manzoori
- Subjects
Chromium ,Luminescence ,Epinephrine ,Metal ions in aqueous solution ,Inorganic chemistry ,chemistry.chemical_element ,Analytical Chemistry ,law.invention ,Nanomaterials ,chemistry.chemical_compound ,law ,Quantum Dots ,Molecule ,Ferricyanides ,Instrumentation ,Spectroscopy ,Chemiluminescence ,Luminescent Agents ,Chemistry ,Water ,Fluorescence ,Carbon ,Atomic and Molecular Physics, and Optics ,Potassium ferricyanide ,Solubility ,Transmission electron microscopy ,Luminescent Measurements ,Oxidation-Reduction - Abstract
The chemiluminescence (CL) of water-soluble fluorescent carbon dots (C-dots) induced by direct chemical oxidation was investigated. C-dots were prepared by solvothermal method and characterized by fluorescence spectra and transmission electron microscopy. It was found that K3Fe(CN)6 could directly oxidize C-dots to produce a relatively intense CL emission. The mechanism of CL generation was investigated based on the fluorescence and CL emission spectra and the effect of radical scavengers on the CL intensity. The inhibitive effect of some metal ions and biologically important molecules on the CL intensity of the system was examined and the potential of the system for the determination of these species at trace levels was studied. In order to evaluate the capability of method to real sample analysis, it was applied to the determination of Cr(VI) and adrenaline in water and injection samples, respectively.
- Published
- 2014
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37. Strong enhancement of the chemiluminescence of the cerium(IV)-thiosulfate reaction by carbon dots, and its application to the sensitive determination of dopamine
- Author
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Mohammad H. Sorouraddin, Mohammad Amjadi, Tooba Hallaj, and Jamshid L. Manzoori
- Subjects
Thiosulfate ,Detection limit ,Inorganic chemistry ,chemistry.chemical_element ,Nanochemistry ,Fluorescence ,Analytical Chemistry ,law.invention ,Cerium ,chemistry.chemical_compound ,chemistry ,Transmission electron microscopy ,law ,Carbon ,Chemiluminescence - Abstract
We show that the very weak chemiluminescence (CL) of the Ce(IV)-thiosulfate system is enhanced by a factor of ~150 in the presence of fluorescent carbon dots (C-dots). The C-dots were prepared by a solvothermal method and characterized by fluorescence spectra and transmission electron microscopy. Possible mechanisms that lead to the effect were elucidated by recording fluorescence and CL spectra. It is found that dopamine at even nanomolar levels exerts a diminishing effect on the enhancement of CL. This was exploited to design a method for the determination of dopamine in the concentration range from 2.5 nM to 20 μM, with a limit of detection (at 3 s) of 1.0 nM. Dopamine was determined by this method in spiked human plasma samples with satisfactory results.
- Published
- 2014
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38. Facile synthesis of carbon quantum dot/silver nanocomposite and its application for colorimetric detection of methimazole
- Author
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Hamideh Asadollahi, Marta de Frutos, Zhenlun Song, Mohammad Amjadi, Niko Hildebrandt, Tooba Hallaj, Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NanoBioPhotonics (NANO), Département Biochimie, Biophysique et Biologie Structurale (B3S), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Calibration curve ,[SDV]Life Sciences [q-bio] ,chemistry.chemical_element ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Silver nanoparticle ,Nano ,Materials Chemistry ,Electrical and Electronic Engineering ,Surface plasmon resonance ,Instrumentation ,ComputingMilieux_MISCELLANEOUS ,Detection limit ,Nanocomposite ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,Quantum dot ,0210 nano-technology ,Carbon ,Nuclear chemistry - Abstract
Here we present a very simple and fast method for preparation of carbon quantum dot/silver (CQD/Ag) nanocomposites at room temperature. Glucose-derived CQDs were prepared by a facile microwave-assisted method and used as both reducing and stabilizing agents for synthesis of CQD/Ag nanocomposites. We found that a unique interaction between as-prepared nanocomposites and anti-thyroid drug methimazole occurs in the solution, which results in a sharp color change from yellow to red. At the same time, the intensity of surface plasmon resonance peak of CQD/Ag nanocomposites at 400 nm decreases and a new peak appears at higher wavelengths. This finding formed a basis for developing a new colorimetric detection method for methimazole. The calibration curve for this drug was linear in the concentration range of 2.0–40 μg L−1 with a detection limit of 1.0 μg L−1. The method was applied to the determination of methimazole in urine samples with satisfactory results.
- Published
- 2017
- Full Text
- View/download PDF
39. A novel chemiluminescence sensor for the determination of indomethacin based on sulfur and nitrogen co-doped carbon quantum dot-KMnO
- Author
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Tooba, Hallaj, Mohammad, Amjadi, Jamshid L, Manzoori, and Neda, Azizi
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Nitrogen ,Anti-Inflammatory Agents, Non-Steroidal ,Indomethacin ,Sensitivity and Specificity ,Carbon ,Microscopy, Electron, Transmission ,Potassium Permanganate ,Limit of Detection ,Calibration ,Luminescent Measurements ,Quantum Dots ,Humans ,Sulfur ,Water Pollutants, Chemical - Abstract
We report on a simple and sensitive sulfur and nitrogen co-doped carbon quantum dot (S,N-CQD)-based chemiluminescence (CL) sensor for the determination of indomethacin. S,N-CQDs were prepared by a hydrothermal method and characterized by fluorescence spectra, Fourier transform infrared spectroscopy and transmission electron microscopy. To obtain the best CL system for determination of indomethacin, the reaction of S,N-CQDs with some common oxidants was studied. Among the tested systems, the S,N-CQD-KMnO
- Published
- 2016
40. Preconcentration of trace cadmium and manganese using 1-(2-pyridylazo)-2-naphthol-modified TiO2nanoparticles and their determination by flame atomic absorption spectrometry
- Author
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Jamshid L. Manzoori, Tooba Hallaj, and Mohammad Amjadi
- Subjects
inorganic chemicals ,Cadmium ,Trace Amounts ,Health, Toxicology and Mutagenesis ,Inorganic chemistry ,Public Health, Environmental and Occupational Health ,Soil Science ,Nanoparticle ,chemistry.chemical_element ,Manganese ,Pollution ,humanities ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,fluids and secretions ,Adsorption ,chemistry ,Flame atomic absorption spectrometry ,law ,Titanium dioxide ,Environmental Chemistry ,Atomic absorption spectroscopy ,Waste Management and Disposal ,Water Science and Technology - Abstract
A new method has been developed for the preconcentration of trace amounts of manganese and cadmium prior to their determination by flame atomic absorption spectrometry (FAAS). The method is based o...
- Published
- 2009
- Full Text
- View/download PDF
41. Interaction of glucose-derived carbon quantum dots with silver and gold nanoparticles and its application for the fluorescence detection of 6-thioguanine
- Author
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Mohammad, Amjadi, Roghayeh, Shokri, and Tooba, Hallaj
- Subjects
Glucose ,Silver ,Spectrometry, Fluorescence ,Surface Properties ,Quantum Dots ,Metal Nanoparticles ,Gold ,Particle Size ,Thioguanine ,Carbon ,Fluorescence - Abstract
The interaction of glucose-derived carbon quantum dots (CQDs) with silver (Ag) and gold (Au) nanoparticles (NPs) was explored by fluorescence spectroscopy. Both metal NPs cause an efficient quenching of CQD fluorescence, which is likely due to the energy transfer process between CQDs as donors and metal NPs as acceptors. The Stern-Volmer plots were evaluated and corresponding quenching constants were found to be 1.9 × 10
- Published
- 2016
42. Terbium Sensitized Chemiluminescence Method for the Determination of Rabeprazole -Application to Pharmaceutical Analysis and Dissolution Studies
- Author
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Amjadi, M., Manzoori, J. L., and Tooba Hallaj
- Subjects
lcsh:QD71-142 ,Rabeprazole ,Sensitized chemiluminescence ,Human plasma ,lcsh:Analytical chemistry ,Terbium(III) ,Cerium(IV)-Sulfite ,Dissolution study - Abstract
A simple and sensitive chemiluminescence-based method was established for the determination of rabeprazole.The proposed method was based on the enhancing effect of rabeprazole on Ce(IV)-Na2SO3 -Tb(III) chemiluminescence reaction. A possible mechanism was discussed for chemiluminescence system by studying UV-Vis, fluorescence and chemiluminescence spectra. The effects of various chemical parameters were investigated and optimized. Under the optimum conditions, the enhanced chemiluminescence intensity was directly proportional to the concentration of rabeprazole in the range of 0.015-0.2 µg ml-1, with a detection limit of 6 ng ml-1. The proposed method was applied to the analysis of pharmaceutical formulations and human plasma samples and to the dissolution study of rabeprazole tablets with satisfactory results. The results indicated that more than 95% of the labeled amount of rabeprazole was dissolved over 30 min in the basic medium, while only 10% of rabeprazole was released in acidic medium.
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