13 results on '"Tabrizi, Mahmoud Amouzadeh"'
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2. A portable electrochemical DNA sensor for sensitive and tunable detection of piconewton-scale cellular forces.
- Author
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Tabrizi MA, Ali AA, Singuru MMR, Mi L, Bhattacharyya P, and You M
- Abstract
Cell-generated forces are a key player in cell biology, especially during cellular shape formation, migration, cancer development, and immune response. A new type of label-free smartphone-based electrochemical DNA sensor is developed here for cellular force measurement. When cells apply tension forces to the DNA sensors, the rapid rupture of DNA duplexes allows multiple redox reporters to reach the electrode and generate highly sensitive electrochemical signals. The sensitivity of these portable sensors can be further enhanced by incorporating a CRISPR-Cas12a system. Meanwhile, the threshold force values of these DNA-based sensors can be rationally tuned based on the force application geometries and also DNA intercalating agents. Overall, these highly sensitive, portable, cost-efficient, and easy-to-use electrochemical sensors can be powerful tools for detecting different cell-generated molecular forces., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Published
- 2024
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3. Electrochemical DNA-based sensors for measuring cell-generated forces.
- Author
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Tabrizi MA, Bhattacharyya P, Zheng R, and You M
- Abstract
Mechanical forces play an important role in cellular communication and signaling. We developed in this study novel electrochemical DNA-based force sensors for measuring cell-generated adhesion forces. Two types of DNA probes, i.e., tension gauge tether and DNA hairpin, were constructed on the surface of a smartphone-based electrochemical device to detect piconewton-scale cellular forces at tunable levels. Upon experiencing cellular tension, the unfolding of DNA probes induces the separation of redox reporters from the surface of the electrode, which results in detectable electrochemical signals. Using integrin-mediated cell adhesion as an example, our results indicated that these electrochemical sensors can be used for highly sensitive, robust, simple, and portable measurement of cell-generated forces., Competing Interests: Competing interests The authors declare no competing interests.
- Published
- 2023
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4. Novel enzyme-based electrochemical and colorimetric biosensors for tetracycline monitoring in milk.
- Author
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Besharati M, Tabrizi MA, Molaabasi F, Saber R, Shamsipur M, Hamedi J, and Hosseinkhani S
- Subjects
- Animals, Electrochemical Techniques, Electrodes, Milk chemistry, Tetracycline analysis, Biosensing Techniques, Colorimetry
- Abstract
Recently, there has been a growing demand to develop portable devices for the fast detection of contaminants in food safety, healthcare, and environmental fields. Herein, two biosensing methods were designed by the use of nicotinamide adenine dinucleotide phosphate (NAD(P)H)-dependent TetX2 enzyme activity and thionine as an excellent electrochemical and colorimetric mediator/probe to monitor tetracycline (TC) in milk. The nanoporous glassy carbon electrode (NPGCE) modified with polythionine was first prepared by electrochemically and then TetX2 was immobilized onto the NPGCE using polyethyleneimine. The prepared biosensor provided a high electrocatalytic response toward NAD(P)H by significantly reducing its overpotential. The proposed biosensor exhibited a detection limit of 40 nM with a linear range of 0.1-0.8 μM for TC determination. Besides, the thionine probe was used to develop a novel colorimetric assay using a simple enzymatic color reaction within a few minutes. The limit of detection for TC was experimentally achieved as 60 nM, which was lower than the safety levels established by the World Health Organization (225 nM). The correlation between change in the color of the solution and the concentration of TC was used for quality control of milk samples, as confirmed by the standard high-performance liquid chromatography method. The results show the great potential of the proposed assays as portable instruments for on-site TC measurements., (© 2020 International Union of Biochemistry and Molecular Biology, Inc.)
- Published
- 2022
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5. Zinc oxide-gold nanocomposite as a proper platform for label-free DNA biosensor.
- Author
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Hatami Z, Ragheb E, Jalali F, Tabrizi MA, and Shamsipur M
- Subjects
- DNA Probes chemistry, Electrochemical Techniques methods, Immobilized Nucleic Acids chemistry, Metal Nanoparticles chemistry, Metal Nanoparticles ultrastructure, Nanocomposites ultrastructure, Nucleic Acid Hybridization methods, Sulfhydryl Compounds chemistry, Biosensing Techniques methods, DNA analysis, Gold chemistry, Nanocomposites chemistry, Zinc Oxide chemistry
- Abstract
In this study, a simple and cost-effective electrochemical DNA biosensor was developed for sensitive detection of mycobacterium tuberculosis (TB). Nanocomposite of zinc oxide (ZnO) and gold nanoparticles (AuNPs) was used as a platform for immobilizing thiolated TB DNA (probe DNA). ZnO was electrodeposited on a glassy carbon electrode by potentiostat electrolysis of Zn (NO
3 )2 solution at -1.0 V (vs. Ag/AgCl), then AuNPs were loaded as the second layer at -0.4 V from HAuCl4 solution. Thiolated probe DNA was then covalently attached to AuNPs. Anodic peak current of Fe (CN)6 3-/4- was followed in hybridization experiments and a linear calibration curve was obtained in concentration range of 2.5-250 pM and limit of detection (LOD) of 1.8 pM for target DNA. The label-free TB biosensor exhibited high selectivity, suitable stability, and reproducibility., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)- Published
- 2020
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6. A photoelectrochemical sandwich immunoassay for protein S100β, a biomarker for Alzheimer's disease, using an ITO electrode modified with a reduced graphene oxide-gold conjugate and CdS-labeled secondary antibody.
- Author
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Tabrizi MA, Ferré-Borrull J, Kapruwan P, and Marsal LF
- Subjects
- Alzheimer Disease metabolism, Biomarkers analysis, Electrochemistry, Electrodes, Models, Molecular, Molecular Conformation, Oxidation-Reduction, Oxides chemistry, Photochemical Processes, Antibodies, Immobilized chemistry, Cadmium Compounds chemistry, Gold chemistry, Graphite chemistry, Immunoassay instrumentation, S100 Calcium Binding Protein beta Subunit analysis, Sulfides chemistry, Tin Compounds chemistry
- Abstract
A sandwich-type photoelectrochemical immunoassay is described for the protein S100ß which is an Alzheimer's disease biomarker found in the astrocytes of the brain. Antibody against S100ß (anti-S100ß) was labeled with CdS quantum dots and then acted as a secondary antibody. The labeled antibody was characterized by FTIR, ultraviolet-visible and fluorescence spectroscopy. An indium-tin oxide (ITO) electrode was modified with a nanocomposite prepared from reduced graphene oxide and gold nanoparticles. Then, a sol-gel film containing isocyanate functional groups (-N=C=O) was cast on the surface of the electrode. The NCO group reacts with amino groups of the labeled antibody to covalently bind them to the surface. The S100β was bound by the primary immobilized antibody on the rGO-Au/ITO electrode and then sandwiched with the labeled secondary antibody. Cyclic voltammetry and electrochemical impedance spectroscopy were applied to confirm the stepwise changes in the electrochemical properties of the electrode surface. The photoelectrochemical immunoassay, typically operated at a potential of +0.2 V (vs. Ag|AgCl
sat ) gives a signal that is related to the logarithm of the S100β concentration in the range from 0.25 to 10 ng·mL-1 with a lower detection limit of 0.15 pg·mL-1 . The method was successfully applied to the determination of S100β in human serum samples. Graphical abstract Schematic presentation of an immunosensor which is based on an indium tin oxide modified with reduced graphene oxide decorated with gold nanocomposite and antibody. The immunosensor was applied for the determination of S100β biomarker by using in the labeled antibody.- Published
- 2019
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7. A highly sensitive electrochemical sensor for the determination of methanol based on PdNPs@SBA-15-PrEn modified electrode.
- Author
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Karimi Z, Shamsipur M, Tabrizi MA, and Rostamnia S
- Subjects
- Oxidation-Reduction, Electrochemical Techniques methods, Metal Nanoparticles chemistry, Methanol analysis, Palladium chemistry, Silicon Dioxide chemistry
- Abstract
In this study, a novel electrochemical sensor for the determination of methanol based on palladium nanoparticles supported on Santa barbara amorphous-15- PrNHEtNH
2 (PdNPs@SBA-15-PrEn) as nanocatalysis platform is presented. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electrochemical methods are employed to characterize the PdNPs@SBA-15-PrEn nanocomposite. The Nafion-Pd@SBA-15-PrEn modified glassy carbon electrode (Nafion-PdNPs@SBA-15-PrEn/GCE) displayed the high electrochemical activity and excellent catalytic characteristic for electro-oxidation of methanol in an alkaline solution. The electro-oxidation performance of the proposed sensor was investigated using cyclic voltammetry (CV) and amperometry. The sensor exhibits a good sensitivity of 0.0905 Amol-1 Lcm-2 , linear range of 20-1000 μM and the corresponding detection limit of 12 μM (3σ). The results demonstrate that the Nafion-PdNPs@SBA-15-PrEn/GCE has potential as an efficient and integrated sensor for methanol detection., (Copyright © 2018 Elsevier Inc. All rights reserved.)- Published
- 2018
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8. CdTe amplification nanoplatforms capped with thioglycolic acid for electrochemical aptasensing of ultra-traces of ATP.
- Author
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Shamsipur M, Farzin L, Tabrizi MA, and Shanehsaz M
- Subjects
- Electrodes, Methylene Blue chemistry, Quantum Dots chemistry, Quantum Dots ultrastructure, Solubility, Spectrophotometry, Ultraviolet, Water chemistry, Adenosine Triphosphate analysis, Aptamers, Nucleotide chemistry, Biosensing Techniques methods, Cadmium Compounds chemistry, Electrochemistry methods, Nanoparticles chemistry, Tellurium chemistry, Thioglycolates chemistry
- Abstract
A "signal off" voltammetric aptasensor was developed for the sensitive and selective detection of ultra-low levels of adenosine triphosphate (ATP). For this purpose, a new strategy based on the principle of recognition-induced switching of aptamers from DNA/DNA duplex to DNA/target complex was designed using thioglycolic acid (TGA)-capped CdTe quantum dots (QDs) as the signal amplifying nano-platforms. Owing to the small size, high surface-to-volume ratio and good conductivity, quantum dots were immobilized on the electrode surface for signal amplification. In this work, methylene blue (MB) adsorbed to DNA was used as a sensitive redox reporter. The intensity of voltammetric signal of MB was found to decrease linearly upon ATP addition over a concentration range of 0.1nM to 1.6μM with a correlation coefficient of 0.9924. Under optimized conditions, the aptasensor was able to selectively detect ATP with a limit of detection of 45pM at 3σ. The results also demonstrated that the QDs-based amplification strategy could be feasible for ATP assay and presented a potential universal method for other small biomolecular aptasensors., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
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9. Achieving direct electrochemistry of glucose oxidase by one step electrochemical reduction of graphene oxide and its use in glucose sensing.
- Author
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Shamsipur M and Tabrizi MA
- Subjects
- Biosensing Techniques, Carbon chemistry, Electrodes, Enzymes, Immobilized chemistry, Enzymes, Immobilized metabolism, Glucose Oxidase metabolism, Hydrogen-Ion Concentration, Oxides chemistry, Sodium Dodecyl Sulfate chemistry, Electrochemical Techniques, Glucose analysis, Glucose Oxidase chemistry, Graphite chemistry
- Abstract
In this paper, the direct electrochemistry of glucose oxidase (GOD) was accomplished at a glassy carbon electrode modified with electrochemically reduced graphene oxide/sodium dodecyl sulfate (GCE/ERGO/SDS). A pair of reversible peaks is exhibited on GCE/ERGO/SDS/GOD by cyclic voltammetry. The peak-to-peak potential separation of immobilized GOD is 28 mV in 0.1 M phosphate buffer solution (pH7.0) with a scan rate of 50 mV/s. The average surface coverage is 2.62×10(-10) mol cm(-2). The resulting biosensor exhibited a good response to glucose with linear range from 1 to 8 mM (R(2)=0.9878), good reproducibility and detection limit of 40.8 μM. The results from the biosensor were similar (±5%) to those obtained from the clinical analyzer., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
- Full Text
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10. Imidazolium or guanidinium/layered manganese (III, IV) oxide hybrid as a promising structural model for the water-oxidizing complex of Photosystem II for artificial photosynthetic systems.
- Author
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Najafpour MM, Tabrizi MA, Haghighi B, Eaton-Rye JJ, Carpentier R, and Allakhverdiev SI
- Subjects
- Electrochemical Techniques, Electrodes, Microscopy, Electron, Transmission, Oxidation-Reduction, Oxygen metabolism, X-Ray Diffraction, Guanidine chemistry, Imidazoles chemistry, Manganese Compounds chemistry, Models, Molecular, Oxides chemistry, Photosynthesis, Photosystem II Protein Complex metabolism, Water metabolism
- Abstract
Photosystem II is responsible for the light-driven biological water-splitting system in oxygenic photosynthesis and contains a cluster of one calcium and four manganese ions at its water-oxidizing complex. This cluster may serve as a model for the design of artificial or biomimetic systems capable of splitting water into oxygen and hydrogen. In this study, we consider the ability of manganese oxide monosheets to self-assemble with organic compounds. Layered structures of manganese oxide, including guanidinium and imidazolium groups, were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, and atomic absorption spectroscopy. The compounds can be considered as new structural models for the water-oxidizing complex of Photosystem II. The overvoltage of water oxidation for the compounds in these conditions at pH = 6.3 is ~0.6 V. These compounds may represent the first step to synthesize a hybrid of guanidinium or imidazole together with manganese as a biomimetic system for the water-oxidizing complex of Photosystem II.
- Published
- 2013
- Full Text
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11. Nano-size layered manganese-calcium oxide as an efficient and biomimetic catalyst for water oxidation under acidic conditions: comparable to platinum.
- Author
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Najafpour MM, Leonard KC, Fan FR, Tabrizi MA, Bard AJ, King'ondu CK, Suib SL, Haghighi B, and Allakhverdiev SI
- Subjects
- Catalysis, Coordination Complexes chemical synthesis, Coordination Complexes chemistry, Crystallography, X-Ray, Electrodes, Hydrogen-Ion Concentration, Molecular Conformation, Oxidation-Reduction, Biomimetic Materials chemistry, Calcium Compounds chemistry, Manganese chemistry, Metal Nanoparticles chemistry, Oxides chemistry, Platinum chemistry, Water chemistry
- Abstract
Inspired by Nature's catalyst, a nano-size layered manganese-calcium oxide showed a low overvoltage for water oxidation in acidic solutions, which is comparable to platinum.
- Published
- 2013
- Full Text
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12. Direct electron transfer from glucose oxidase immobilized on an overoxidized polypyrrole film decorated with Au nanoparticles.
- Author
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Haghighi B and Tabrizi MA
- Subjects
- Carbon chemistry, Electrochemical Techniques, Electrodes, Glucose analysis, Hydrodynamics, Metal Nanoparticles ultrastructure, Oxidation-Reduction, Aspergillus niger enzymology, Electrons, Enzymes, Immobilized metabolism, Glucose Oxidase metabolism, Gold chemistry, Metal Nanoparticles chemistry, Polymers chemistry, Pyrroles chemistry
- Abstract
An overoxidized polypyrrole (OOPPy) film was electrodeposited on a glassy carbon electrode (GCE) and the modified electrode (GCE/OOPPy) was then decorated with Au nanoparticles (nanoAu). Glucose oxidase was immobilized on the surface of nanoAu decorated OOPPy modified GCE to fabricate a novel glucose biosensor (GCE/OOPPy-nanoAu/GOx). Cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) were used to characterize the modified electrodes. A pair of well-defined redox peaks with a formal potential (E°') of -0.449 V and a peak to peak separation (ΔE(p)) of 28 mV was observed for the direct electron transfer (DET) of the immobilized GOx. The electron transfer rate constant (k(s)) was calculated to be 10.3 s(-1). The fabricated glucose biosensor was employed for the determination of glucose in the concentration range between 1 and 8mM using cyclic voltammetry and amperometry. The results clearly demonstrate that nanoAu decorated OOPPy film is an excellent biocompatible scaffold for the immobilization of GOx and fabrication of a glucose biosensor., (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Published
- 2013
- Full Text
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13. A manganese oxide with phenol groups as a promising structural model for water oxidizing complex in Photosystem II: a 'golden fish'.
- Author
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Najafpour MM, Tabrizi MA, Haghighi B, and Govindjee
- Subjects
- Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Oxidation-Reduction, Powder Diffraction, Spectroscopy, Fourier Transform Infrared, Water chemistry, X-Ray Diffraction, Aminophenols chemistry, Manganese Compounds chemistry, Oxides chemistry, Photosystem II Protein Complex chemistry
- Abstract
We describe here the ability of manganese oxide monosheets to aggregate to form layered structures with 4-aminophenol molecules. These aggregated monosheets could be considered as the first step to synthesize a self-assembled layered hybrid of phenol-manganese ions with phenol and manganese(III) and (IV) as exists in the water oxidizing complex of Photosystem II.
- Published
- 2012
- Full Text
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