Razieh Amiri | University of Isfahan (original) (raw)
Papers by Razieh Amiri
As a dedicated physical chemist, I bring a solid academic background and extensive research exper... more As a dedicated physical chemist, I bring a solid academic background and extensive research experience in protein chemistry, nanotechnology, biosensors, and advanced spectroscopic techniques. My expertise in protein interactions and nanomaterials is demonstrated through a proven record of research publications in high-impact journals. I am particularly proud of being recognized for excellence in academic and research contributions, which assures you of my competence. Academic Qualifications Ph.D. in Physical Chemistry University of Isfahan, Thesis: Energetic and structural studies on protein-surfactant interactions using NMR, Circular Dichroism, and Fluorescence Spectroscopies. Skills Spectroscopic Techniques: NMR (1D & 2D), FT
Proceeding of the 33rd European Safety and Reliability Conference
Home fires can cause fatalities, severe injuries, and damage to the household assets. Statistics ... more Home fires can cause fatalities, severe injuries, and damage to the household assets. Statistics indicate that the current fire safety measures are not effective for all types of dwellers. In many countries, majority of fire fatalities occurs mostly among vulnerable groups. The main objective of this paper is to conduct a systematic literature review in the field of residential fire safety and to evaluate fire safety measures in two perspectives. First, it is investigated which dimensions of fire safety are addressed, such as individual needs, the technical and physical environment, as well as the social and organizational environment. Second, it is investigated whether the studies focused more toward preventing the causes, and/or the consequences. Out of the initial 1303 studies from three search engines, 437 studies were selected for further assessment. The results show that the amount of published research in residential fire safety is generally increasing during the last decades. In recent years only, research has addressed all the three dimensions: individual needs, the technical and physical environment, as well as the social and organizational environment. Considering the total number of articles focusing on preventing the causes and/or consequences, the existing literature seems to be leaning toward measures reducing the consequence of the fire. The studies that aimed to address both causes and consequences, are likely to address more than one of the three dimensions. While research on individual measures and technologies are highly valuable, research that focuses on the interplay of individual needs, the technical and physical environment, as well as the social and organizational environment in residential fire safety can lead to new insights and better prioritization of measures. This can especially be useful in terms of prioritizing and aiding the implementation of measures, thus providing policymakers, governments, and authorities information that can contribute to achieving higher fire safety levels in homes. The need to include the "soft" dimensions of fire prevention is further emphasized by the fact that the majority of residential fires harm specific vulnerable groups. This understanding can be crucial to develop new solutions and measures to find and target the most important ones that can be connected to fire causes and hazardous events, and it can only be achievable through multidisciplinary cooperation with different groups of expertise including health care, social science and humanities, technical fire safety, relevant authorities, stakeholders, as well as representatives for the risk groups and the vulnerable communities.
Journal of The Taiwan Institute of Chemical Engineers, Nov 1, 2017
Generally, heavy metal ions derived from different industrial sources are absorbed by organisms' ... more Generally, heavy metal ions derived from different industrial sources are absorbed by organisms' ecosystems, causing serious illnesses. Therefore, removing them by a new and practical technique is essential. In this study, poly(acrylonitrile co maleic acid) nanofibers were prepared by the electrospinning technique for the removal of heavy metal ions Ni(II) and Cr(VI) from water. Firstly, polymer concentration (w/w %), applied voltage (kV), and the distance tip to collector (cm) values were optimized to find the finest nanofiber by employing response surface methodology. The minimum average of the nanofiber diameters of SEM images and the minimum standard deviation without beads were considered as the criteria for the selection of the aforementioned parameters; also, they were converged at 5.2%, 10.2 kV, and 16.3 cm, respectively. The nanofiber diameter averaged was obtained to be 180.7 nm. Secondly, the effects of contact time (min), stirring rate (rpm) and the pH of the mixed nanofibers and heavy metal ions solutions were investigated to find the maximum adsorption of ions by the nanofiber mats. These values were, respectively, obtained to be 20 and 15 min, 1250, and 10 0 0 rpm; also, they were 6 and 4 for Ni(II) and Cr(VI) ions, respectively. In addition, the adsorption values of heavy metal ions by the nanofiber mats were reported in this study, showing that the nanofiber sites for adsorption Ni(II) ions could be more appropriate than its Cr(VI) ions.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Dec 1, 2021
Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the a... more Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the attachment of Na+ and Li+ ions to four dipeptides including phenylalanyl-alanine (Phe-Ala), tyrosyl-alanine (Tyr-Ala), L-Phenylalanyl-L-Phenylalanine (Phe-Phe), and alanyl-glutamine (Ala-Gln) dipeptides. The LiCl, NaOH, and NaF salts are used as the source of Li+ and Na+ ions in the LDI of the dipeptides. Our aim is the investigation of the difference between the fragmentation patterns of the selected dipeptides in the presence of Na+ and Li+ ions due to the laser radiation and providing information for the fragmentation of larger peptides in the same conditions. The characteristic peak, related to [dipeptide-H + 2Na]+ species, is observed in the mass spectrum of Phe-Ala and Tyr-Ala dipeptides in the presence of NaF, while the breaking of the peptide bond (OC-NH) occurs for the Phe-Phe in the presence of the aforementioned salts. The characteristic peak of Ala-Gln dipeptide ([(Ala-Gln)-H + 2Na]+) is observed in the absence of any salt. The mass spectra of the dipeptides, recorded in the presence of LiCl, are crowded compared to those recorded in the presence of NaF and NaOH showing the effect of the type of alkali salt on the dipeptide fragmentation. The theoretical calculations are employed to investigate the ability of the interaction sites of dipeptides for the attachment of one and two Na+ and determine the most stable structure of the [dipeptide-H + 2Na]+ species for each dipeptide.
Applied Organometallic Chemistry, Apr 11, 2019
The Glucose amount of human blood is very vital because in higher levels than allowed value the c... more The Glucose amount of human blood is very vital because in higher levels than allowed value the corporal biological system was hampered. Therefore, in this study, the Cu 2 O was deposited on the reduced Graphene oxide (RGO) by polydopamin (PDA) as linker. The new RGO-PDA-Cu 2 O nanocomposite was deposited on the glassy carbon electrode (GCE) surface after its characterization by UV-Visible, fourier transform infrared (FT-IR), X-ray diffraction (XRD), Energy-dispersive X-ray (EDX), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques. The electroanalysis of the new electrode was investigated by the cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) methods. The obtained detection limit of glucose (Glu) showed that the deposited GCE by RGO-PDA-Cu 2 O nanocomposite has a high potential for its diagnosis. In addition, this electrode was applied to the Glu detection as biosensor in real samples in order to utilize in commercial applications.
Journal of Electroanalytical Chemistry, Apr 1, 2019
Quick, inexpensive and accurate methods are needed for glucose determination in many biochemical ... more Quick, inexpensive and accurate methods are needed for glucose determination in many biochemical and medical labs. The purpose of this study is to develop and test a novel inexpensive electrode based on nickel/ gamma-aminopropyltriethoxysilane nanoparticles for measuring glucose concentrations. First, the Ni nanoparticles (Ni NPs) were synthesized by a bottom-up approach. Then, the Ni NPs and gamma-Aminopropyltriethoxysilane (KH550) were mixed at 60°C under a nitrogen atmosphere to produce Ni/KH550 nanocomposite. Afterwards, the synthesized Ni/KH550 nanocomposites were characterized using different methods such as Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Next, the surface of a glassy carbon electrode (GCE) was polished and washed with alumina powder and deionized water, respectively; and ultrasonicated in the H 2 O/ethanol solution. Then, the nanocomposite suspension was pipetted dropwise on the GCE surface and dried to GCE-Ni/KH550 production. The newly prepared electrode was characterized and applied to glucose detection utilizing electrochemical methods. The cyclic voltammetry measurements showed that the oxidation peak of glucose appeared at a potential of about 0.53 V (vs. Ag/AgCl) on the surface of the modified GCE. Differential pulse voltammetry exhibited two wide linear dynamic ranges of 0.5-20 and 100-500 μM glucose with a detection limit of 0.043 μM. Finally, measurements of glucose in a real sample using our designed sensor indicated that GCE-Ni/KH550 is as good as those obtained with a high efficiency, commercial apparatus.
Journal of Materials Science: Materials in Electronics, May 8, 2017
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2021
Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the a... more Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the attachment of Na+ and Li+ ions to four dipeptides including phenylalanyl-alanine (Phe-Ala), tyrosyl-alanine (Tyr-Ala), L-Phenylalanyl-L-Phenylalanine (Phe-Phe), and alanyl-glutamine (Ala-Gln) dipeptides. The LiCl, NaOH, and NaF salts are used as the source of Li+ and Na+ ions in the LDI of the dipeptides. Our aim is the investigation of the difference between the fragmentation patterns of the selected dipeptides in the presence of Na+ and Li+ ions due to the laser radiation and providing information for the fragmentation of larger peptides in the same conditions. The characteristic peak, related to [dipeptide-H + 2Na]+ species, is observed in the mass spectrum of Phe-Ala and Tyr-Ala dipeptides in the presence of NaF, while the breaking of the peptide bond (OC-NH) occurs for the Phe-Phe in the presence of the aforementioned salts. The characteristic peak of Ala-Gln dipeptide ([(Ala-Gln)-H ...
Journal of the Chinese Chemical Society, 2021
Applied Surface Science, 2016
Abstract Immobilized proteins and enzymes are widely investigated in the medical field as well as... more Abstract Immobilized proteins and enzymes are widely investigated in the medical field as well as the food and environmental fields. In this study, glucose oxidase (GOX) was covalently immobilized on the surface of modified iron oxide magnetic nanoparticles (MIMNs) to produce a bioconjugate complex. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to the size, shape and structure characterization of the MIMNs. Binding of GOX to these MIMNs was confirmed by using FT-IR spectroscopy. The stability of the immobilized and free enzyme at different temperature and pH values was investigated by measuring the enzymatic activity. These studies reveal that the enzyme's stability is enhanced by immobilization. Further experiments showed that the storage stability of the enzyme is improved upon binding to the MIMNs. The results of kinetic measurements suggest that the effect of the immobilization process on substrate and product diffusion is small. Such bioconjugates can be considered as a catalytic nanodevice for accelerating the glucose oxidation reaction for biotechnological purposes.
![Research paper thumbnail of In vitro antitumor activity of free and nano-encapsulated Na5[PMo10V2O40]·nH2O and its binding properties with ctDNA by using combined spectroscopic methods](https://attachments.academia-assets.com/84660659/thumbnails/1.jpg)
](Journal of Inorganic Biochemistry, 2015
Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as P... more Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as PMoV, SEP and LEP, respectively) have been prepared and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma (ICP) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The results show that the PMoV retains its parent structure after encapsulation by starch and lipid nanoparticles. The in vitro antitumor activity of PMoV in its free and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay that was carried out on two types of human cancer cells, MCF-7 (breast cancer cells) and HEK-293 (Human Embryonic Kidney). The results represent the enhancement of cell penetration and antitumor activity of PMoV due to its encapsulation in starch or lipid nanoparticles. However, this observed enhancement for the lipid relative to the starch nanocapsule can be attributed to its smaller size. In order to investigate the molecular nature of antitumor activity, the binding properties of PMoV with calf thymus DNA (ctDNA) were also comprehensively evaluated using UV-vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. The results rule out the intercalating binding mode and propose the groove or outside stacking binding for PMoV. However, a biphasic binding behavior that is due to the change in the binding mode was observed by varying of [PMoV]/[ctDNA] mole ratio. The results of cell culture assay and DNA binding experiments represent that the rate of cell penetration is more important than DNA binding affinity in the antitumor activity for POM.
The Journal of Physical Chemistry B, 2014
Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond mono... more Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA.
Journal of Thermal Analysis and Calorimetry, 2014
ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been inv... more ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been investigated by means of UV–Vis spectroscopy and isothermal titration calorimetry. First, the values of the first and second associative stepwise binding constants of Ga(ma)3 to apotransferrin were estimated by use of a data analyzing method. The synergistic role of the carbonate anion in the formation of gallium-transferrin bonds was also investigated. Experimental results indicated that the extent of binding is maximum at physiological pH. Citrate ion and transferrin have a competitive behavior toward gallium binding. By use of the calorimetric results, the values of 23.44 and 8.99 kJ mol−1 were determined for the associative stepwise enthalpy changes. This represents the endothermic entropy-driven nature of the process.
Journal of Colloid and Interface Science, 2012
Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacologica... more Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant milk protein that is highly amphiphilic and self-assembles into stable micellar nanoparticles in aqueous solution. β-Casein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drug-delivery system comprising hydrophobic anticancer drug, CUR, entrapped within β-casein-based nanoparticles. The interaction of CUR with β-casein was investigated using steady-state fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to β-casein micelle and formed complexes through hydrophobic interactions. Förster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of β-casein. The binding parameters including number of su...
Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacologica... more Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant milk protein that is highly amphiphilic and self-assembles into stable micellar nanoparticles in aqueous solution. β-Casein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drug-delivery system comprising hydrophobic anticancer drug, CUR, entrapped within β-casein-based nanoparticles. The interaction of CUR with β-casein was investigated using steady-state fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to β-casein micelle and formed complexes through hydrophobic interactions. Forster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of βcasein. The binding parameters including number of sub...
Because of the many applications of surfactants in bioscience, drug delivery, and biotechnologica... more Because of the many applications of surfactants in bioscience, drug delivery, and biotechnological processes, they are one of the most significant classes of applied ligands and their interaction with different proteins has been studied widely. The conformational stability of ribonuclease A (RNase A) has been measured at the per residue level by NMR-monitored hydrogen exchange in the absence and presence of cationic gemini surfactants. The hydrogen/deutrium exchange mechanism of RNase A has been found EXII in these conditions. We used gemini surfactants alkanediyl -α,ω-bis (Hydroxy ethyl methyl hexadecyl ammonium bromide) in this study. 1D NMR experiments showed gemini surfactants bind to DSS. 2D 1H-NMR spectroscopy shows that the conformation of RNase A is unaffected at acidic pH where this protein is positively charged, although hydrogen exchange results shows that the conformational stability of RNase A is slightly lowered at high molar ratios and acidic pH. At low molar ratios, ...
Applied Surface Science
In this study, the NiFe 2 O 4 was embedded in (3-mercaptopropyl) trimethoxysilane (TPS) and tetra... more In this study, the NiFe 2 O 4 was embedded in (3-mercaptopropyl) trimethoxysilane (TPS) and tetraethyl orthosilicate (TEOS) using the sol-gel method. These compounds were used as the support of Ag nanoparticles (Ag NPs). The NiFe 2 O 4 @TEOS-TPS@Ag nanocomposites were obtained with the development of bonding between the silver atoms of Ag NPs and the sulfur atoms of TPS molecule. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of the Ag nanocomposites. Also, the magnetic properties of these nanocomposites were studied by using a vibrating sample magnetometer (VSM) technique. The disk diffusion, minimum inhibition concentration (MIC) and minimum bactericidal concentrations (MBC) tests were used for the investigation of the antibacterial effect of this nanocomposite against bacterial strains. The synthesized nanocomposite presented high reusability and good antibacterial activity against gram-positive and gram-negative bacteria. Remarkably, this nanocomposite could be easily removed from the disinfected media by magnetic decantation.
Biotechnology Research International, 2014
Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coat... more Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction, and then were activated with 2,4,6-trichloro-1,3,5-triazine (TCT) and covalently immobilized with bovine serum albumin (BSA). The size and structure of the particles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and dynamic light scattering (DLS) techniques. The immobilization was confirmed by Fourier transform infrared spectroscopy (FT-IR). XRD analysis showed that the binding process has not done any phase change to Fe3O4. The immobilization time for this process was 4 h and the amount of immobilized BSA for the initial value of 1.05 mg BSA was about 120 mg/gr nanoparticles. Also, the influences of three different buffer solutions and ionic strength on covalent immobilization were evaluated.
As a dedicated physical chemist, I bring a solid academic background and extensive research exper... more As a dedicated physical chemist, I bring a solid academic background and extensive research experience in protein chemistry, nanotechnology, biosensors, and advanced spectroscopic techniques. My expertise in protein interactions and nanomaterials is demonstrated through a proven record of research publications in high-impact journals. I am particularly proud of being recognized for excellence in academic and research contributions, which assures you of my competence. Academic Qualifications Ph.D. in Physical Chemistry University of Isfahan, Thesis: Energetic and structural studies on protein-surfactant interactions using NMR, Circular Dichroism, and Fluorescence Spectroscopies. Skills Spectroscopic Techniques: NMR (1D & 2D), FT
Proceeding of the 33rd European Safety and Reliability Conference
Home fires can cause fatalities, severe injuries, and damage to the household assets. Statistics ... more Home fires can cause fatalities, severe injuries, and damage to the household assets. Statistics indicate that the current fire safety measures are not effective for all types of dwellers. In many countries, majority of fire fatalities occurs mostly among vulnerable groups. The main objective of this paper is to conduct a systematic literature review in the field of residential fire safety and to evaluate fire safety measures in two perspectives. First, it is investigated which dimensions of fire safety are addressed, such as individual needs, the technical and physical environment, as well as the social and organizational environment. Second, it is investigated whether the studies focused more toward preventing the causes, and/or the consequences. Out of the initial 1303 studies from three search engines, 437 studies were selected for further assessment. The results show that the amount of published research in residential fire safety is generally increasing during the last decades. In recent years only, research has addressed all the three dimensions: individual needs, the technical and physical environment, as well as the social and organizational environment. Considering the total number of articles focusing on preventing the causes and/or consequences, the existing literature seems to be leaning toward measures reducing the consequence of the fire. The studies that aimed to address both causes and consequences, are likely to address more than one of the three dimensions. While research on individual measures and technologies are highly valuable, research that focuses on the interplay of individual needs, the technical and physical environment, as well as the social and organizational environment in residential fire safety can lead to new insights and better prioritization of measures. This can especially be useful in terms of prioritizing and aiding the implementation of measures, thus providing policymakers, governments, and authorities information that can contribute to achieving higher fire safety levels in homes. The need to include the "soft" dimensions of fire prevention is further emphasized by the fact that the majority of residential fires harm specific vulnerable groups. This understanding can be crucial to develop new solutions and measures to find and target the most important ones that can be connected to fire causes and hazardous events, and it can only be achievable through multidisciplinary cooperation with different groups of expertise including health care, social science and humanities, technical fire safety, relevant authorities, stakeholders, as well as representatives for the risk groups and the vulnerable communities.
Journal of The Taiwan Institute of Chemical Engineers, Nov 1, 2017
Generally, heavy metal ions derived from different industrial sources are absorbed by organisms' ... more Generally, heavy metal ions derived from different industrial sources are absorbed by organisms' ecosystems, causing serious illnesses. Therefore, removing them by a new and practical technique is essential. In this study, poly(acrylonitrile co maleic acid) nanofibers were prepared by the electrospinning technique for the removal of heavy metal ions Ni(II) and Cr(VI) from water. Firstly, polymer concentration (w/w %), applied voltage (kV), and the distance tip to collector (cm) values were optimized to find the finest nanofiber by employing response surface methodology. The minimum average of the nanofiber diameters of SEM images and the minimum standard deviation without beads were considered as the criteria for the selection of the aforementioned parameters; also, they were converged at 5.2%, 10.2 kV, and 16.3 cm, respectively. The nanofiber diameter averaged was obtained to be 180.7 nm. Secondly, the effects of contact time (min), stirring rate (rpm) and the pH of the mixed nanofibers and heavy metal ions solutions were investigated to find the maximum adsorption of ions by the nanofiber mats. These values were, respectively, obtained to be 20 and 15 min, 1250, and 10 0 0 rpm; also, they were 6 and 4 for Ni(II) and Cr(VI) ions, respectively. In addition, the adsorption values of heavy metal ions by the nanofiber mats were reported in this study, showing that the nanofiber sites for adsorption Ni(II) ions could be more appropriate than its Cr(VI) ions.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Dec 1, 2021
Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the a... more Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the attachment of Na+ and Li+ ions to four dipeptides including phenylalanyl-alanine (Phe-Ala), tyrosyl-alanine (Tyr-Ala), L-Phenylalanyl-L-Phenylalanine (Phe-Phe), and alanyl-glutamine (Ala-Gln) dipeptides. The LiCl, NaOH, and NaF salts are used as the source of Li+ and Na+ ions in the LDI of the dipeptides. Our aim is the investigation of the difference between the fragmentation patterns of the selected dipeptides in the presence of Na+ and Li+ ions due to the laser radiation and providing information for the fragmentation of larger peptides in the same conditions. The characteristic peak, related to [dipeptide-H + 2Na]+ species, is observed in the mass spectrum of Phe-Ala and Tyr-Ala dipeptides in the presence of NaF, while the breaking of the peptide bond (OC-NH) occurs for the Phe-Phe in the presence of the aforementioned salts. The characteristic peak of Ala-Gln dipeptide ([(Ala-Gln)-H + 2Na]+) is observed in the absence of any salt. The mass spectra of the dipeptides, recorded in the presence of LiCl, are crowded compared to those recorded in the presence of NaF and NaOH showing the effect of the type of alkali salt on the dipeptide fragmentation. The theoretical calculations are employed to investigate the ability of the interaction sites of dipeptides for the attachment of one and two Na+ and determine the most stable structure of the [dipeptide-H + 2Na]+ species for each dipeptide.
Applied Organometallic Chemistry, Apr 11, 2019
The Glucose amount of human blood is very vital because in higher levels than allowed value the c... more The Glucose amount of human blood is very vital because in higher levels than allowed value the corporal biological system was hampered. Therefore, in this study, the Cu 2 O was deposited on the reduced Graphene oxide (RGO) by polydopamin (PDA) as linker. The new RGO-PDA-Cu 2 O nanocomposite was deposited on the glassy carbon electrode (GCE) surface after its characterization by UV-Visible, fourier transform infrared (FT-IR), X-ray diffraction (XRD), Energy-dispersive X-ray (EDX), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques. The electroanalysis of the new electrode was investigated by the cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) methods. The obtained detection limit of glucose (Glu) showed that the deposited GCE by RGO-PDA-Cu 2 O nanocomposite has a high potential for its diagnosis. In addition, this electrode was applied to the Glu detection as biosensor in real samples in order to utilize in commercial applications.
Journal of Electroanalytical Chemistry, Apr 1, 2019
Quick, inexpensive and accurate methods are needed for glucose determination in many biochemical ... more Quick, inexpensive and accurate methods are needed for glucose determination in many biochemical and medical labs. The purpose of this study is to develop and test a novel inexpensive electrode based on nickel/ gamma-aminopropyltriethoxysilane nanoparticles for measuring glucose concentrations. First, the Ni nanoparticles (Ni NPs) were synthesized by a bottom-up approach. Then, the Ni NPs and gamma-Aminopropyltriethoxysilane (KH550) were mixed at 60°C under a nitrogen atmosphere to produce Ni/KH550 nanocomposite. Afterwards, the synthesized Ni/KH550 nanocomposites were characterized using different methods such as Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Next, the surface of a glassy carbon electrode (GCE) was polished and washed with alumina powder and deionized water, respectively; and ultrasonicated in the H 2 O/ethanol solution. Then, the nanocomposite suspension was pipetted dropwise on the GCE surface and dried to GCE-Ni/KH550 production. The newly prepared electrode was characterized and applied to glucose detection utilizing electrochemical methods. The cyclic voltammetry measurements showed that the oxidation peak of glucose appeared at a potential of about 0.53 V (vs. Ag/AgCl) on the surface of the modified GCE. Differential pulse voltammetry exhibited two wide linear dynamic ranges of 0.5-20 and 100-500 μM glucose with a detection limit of 0.043 μM. Finally, measurements of glucose in a real sample using our designed sensor indicated that GCE-Ni/KH550 is as good as those obtained with a high efficiency, commercial apparatus.
Journal of Materials Science: Materials in Electronics, May 8, 2017
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2021
Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the a... more Laser desorption ionization-time of flight (LDI-TOF) mass spectrometry is used for studying the attachment of Na+ and Li+ ions to four dipeptides including phenylalanyl-alanine (Phe-Ala), tyrosyl-alanine (Tyr-Ala), L-Phenylalanyl-L-Phenylalanine (Phe-Phe), and alanyl-glutamine (Ala-Gln) dipeptides. The LiCl, NaOH, and NaF salts are used as the source of Li+ and Na+ ions in the LDI of the dipeptides. Our aim is the investigation of the difference between the fragmentation patterns of the selected dipeptides in the presence of Na+ and Li+ ions due to the laser radiation and providing information for the fragmentation of larger peptides in the same conditions. The characteristic peak, related to [dipeptide-H + 2Na]+ species, is observed in the mass spectrum of Phe-Ala and Tyr-Ala dipeptides in the presence of NaF, while the breaking of the peptide bond (OC-NH) occurs for the Phe-Phe in the presence of the aforementioned salts. The characteristic peak of Ala-Gln dipeptide ([(Ala-Gln)-H ...
Journal of the Chinese Chemical Society, 2021
Applied Surface Science, 2016
Abstract Immobilized proteins and enzymes are widely investigated in the medical field as well as... more Abstract Immobilized proteins and enzymes are widely investigated in the medical field as well as the food and environmental fields. In this study, glucose oxidase (GOX) was covalently immobilized on the surface of modified iron oxide magnetic nanoparticles (MIMNs) to produce a bioconjugate complex. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to the size, shape and structure characterization of the MIMNs. Binding of GOX to these MIMNs was confirmed by using FT-IR spectroscopy. The stability of the immobilized and free enzyme at different temperature and pH values was investigated by measuring the enzymatic activity. These studies reveal that the enzyme's stability is enhanced by immobilization. Further experiments showed that the storage stability of the enzyme is improved upon binding to the MIMNs. The results of kinetic measurements suggest that the effect of the immobilization process on substrate and product diffusion is small. Such bioconjugates can be considered as a catalytic nanodevice for accelerating the glucose oxidation reaction for biotechnological purposes.
Journal of Inorganic Biochemistry, 2015
Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as P... more Free and nanosized starch and lipid encapsulated Na5[PMo10V2O40]·nH2O complexes (abbreviated as PMoV, SEP and LEP, respectively) have been prepared and structurally characterized by Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma (ICP) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The results show that the PMoV retains its parent structure after encapsulation by starch and lipid nanoparticles. The in vitro antitumor activity of PMoV in its free and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay that was carried out on two types of human cancer cells, MCF-7 (breast cancer cells) and HEK-293 (Human Embryonic Kidney). The results represent the enhancement of cell penetration and antitumor activity of PMoV due to its encapsulation in starch or lipid nanoparticles. However, this observed enhancement for the lipid relative to the starch nanocapsule can be attributed to its smaller size. In order to investigate the molecular nature of antitumor activity, the binding properties of PMoV with calf thymus DNA (ctDNA) were also comprehensively evaluated using UV-vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. The results rule out the intercalating binding mode and propose the groove or outside stacking binding for PMoV. However, a biphasic binding behavior that is due to the change in the binding mode was observed by varying of [PMoV]/[ctDNA] mole ratio. The results of cell culture assay and DNA binding experiments represent that the rate of cell penetration is more important than DNA binding affinity in the antitumor activity for POM.
The Journal of Physical Chemistry B, 2014
Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond mono... more Gemini surfactants have important advantages, e.g., low micromolar CMCs and slow millisecond monomer ↔ micelle kinetics, for membrane mimetics and for delivering nucleic acids for gene therapy or RNA silencing. However, as a prerequisite, it is important to characterize interactions occurring between Gemini surfactants and proteins. Here NMR and CD spectroscopies are employed to investigate the interactions of cationic Gemini surfactants with RNase Sa, a negatively charged ribonuclease. We find that RNase Sa binds Gemini surfactant monomers and micelles at pH values above 4 to form aggregates. Below pH 4, where the protein is positively charged, these aggregates dissolve and interactions are undetectable. Thermal denaturation experiments show that surfactant lowers RNase Sa's conformational stability, suggesting that surfactant binds the protein's denatured state preferentially. Finally, Gemini surfactants were found to bind RNA, leading to the formation of large complexes. Interestingly, Gemini surfactant binding did not prevent RNase Sa from cleaving RNA.
Journal of Thermal Analysis and Calorimetry, 2014
ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been inv... more ABSTRACT The interaction of gallium maltolate (Ga(ma)3) with human serum transferrin has been investigated by means of UV–Vis spectroscopy and isothermal titration calorimetry. First, the values of the first and second associative stepwise binding constants of Ga(ma)3 to apotransferrin were estimated by use of a data analyzing method. The synergistic role of the carbonate anion in the formation of gallium-transferrin bonds was also investigated. Experimental results indicated that the extent of binding is maximum at physiological pH. Citrate ion and transferrin have a competitive behavior toward gallium binding. By use of the calorimetric results, the values of 23.44 and 8.99 kJ mol−1 were determined for the associative stepwise enthalpy changes. This represents the endothermic entropy-driven nature of the process.
Journal of Colloid and Interface Science, 2012
Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacologica... more Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant milk protein that is highly amphiphilic and self-assembles into stable micellar nanoparticles in aqueous solution. β-Casein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drug-delivery system comprising hydrophobic anticancer drug, CUR, entrapped within β-casein-based nanoparticles. The interaction of CUR with β-casein was investigated using steady-state fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to β-casein micelle and formed complexes through hydrophobic interactions. Förster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of β-casein. The binding parameters including number of su...
Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacologica... more Curcumin (CUR) is the active curcuminoid with many physiological, biochemical, and pharmacological properties. Solubility and stability of CUR is the limiting factors for realizing its therapeutic potential. Bovine β-casein is an abundant milk protein that is highly amphiphilic and self-assembles into stable micellar nanoparticles in aqueous solution. β-Casein nanoparticle can solubilize CUR molecules. In the present study, we introduced a drug-delivery system comprising hydrophobic anticancer drug, CUR, entrapped within β-casein-based nanoparticles. The interaction of CUR with β-casein was investigated using steady-state fluorescence spectroscopy and molecular docking calculation. Results showed that at pH 7, CUR molecules bind to β-casein micelle and formed complexes through hydrophobic interactions. Forster energy transfer measurements and molecular docking studies suggested that CUR molecules bind to the hydrophobic core of βcasein. The binding parameters including number of sub...
Because of the many applications of surfactants in bioscience, drug delivery, and biotechnologica... more Because of the many applications of surfactants in bioscience, drug delivery, and biotechnological processes, they are one of the most significant classes of applied ligands and their interaction with different proteins has been studied widely. The conformational stability of ribonuclease A (RNase A) has been measured at the per residue level by NMR-monitored hydrogen exchange in the absence and presence of cationic gemini surfactants. The hydrogen/deutrium exchange mechanism of RNase A has been found EXII in these conditions. We used gemini surfactants alkanediyl -α,ω-bis (Hydroxy ethyl methyl hexadecyl ammonium bromide) in this study. 1D NMR experiments showed gemini surfactants bind to DSS. 2D 1H-NMR spectroscopy shows that the conformation of RNase A is unaffected at acidic pH where this protein is positively charged, although hydrogen exchange results shows that the conformational stability of RNase A is slightly lowered at high molar ratios and acidic pH. At low molar ratios, ...
Applied Surface Science
In this study, the NiFe 2 O 4 was embedded in (3-mercaptopropyl) trimethoxysilane (TPS) and tetra... more In this study, the NiFe 2 O 4 was embedded in (3-mercaptopropyl) trimethoxysilane (TPS) and tetraethyl orthosilicate (TEOS) using the sol-gel method. These compounds were used as the support of Ag nanoparticles (Ag NPs). The NiFe 2 O 4 @TEOS-TPS@Ag nanocomposites were obtained with the development of bonding between the silver atoms of Ag NPs and the sulfur atoms of TPS molecule. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used for the characterization of the Ag nanocomposites. Also, the magnetic properties of these nanocomposites were studied by using a vibrating sample magnetometer (VSM) technique. The disk diffusion, minimum inhibition concentration (MIC) and minimum bactericidal concentrations (MBC) tests were used for the investigation of the antibacterial effect of this nanocomposite against bacterial strains. The synthesized nanocomposite presented high reusability and good antibacterial activity against gram-positive and gram-negative bacteria. Remarkably, this nanocomposite could be easily removed from the disinfected media by magnetic decantation.
Biotechnology Research International, 2014
Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coat... more Magnetite Fe3O4 nanoparticles (NPs) were prepared by chemical coprecipitation method. Silica-coated magnetite NPs were prepared by sol-gel reaction, subsequently coated with 3-aminopropyltriethoxysilane (APTES) via silanization reaction, and then were activated with 2,4,6-trichloro-1,3,5-triazine (TCT) and covalently immobilized with bovine serum albumin (BSA). The size and structure of the particles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and dynamic light scattering (DLS) techniques. The immobilization was confirmed by Fourier transform infrared spectroscopy (FT-IR). XRD analysis showed that the binding process has not done any phase change to Fe3O4. The immobilization time for this process was 4 h and the amount of immobilized BSA for the initial value of 1.05 mg BSA was about 120 mg/gr nanoparticles. Also, the influences of three different buffer solutions and ionic strength on covalent immobilization were evaluated.