فهرست مطالب

Nano Structures - Volume:9 Issue:2, 2019
  • Volume:9 Issue:2, 2019
  • تاریخ انتشار: 1398/01/12
  • تعداد عناوین: 20
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  • Ali Babaei *, Sara Soleimani Babadi, Masoud Sohrabi Pages 190-201
    A novel chemically modified electrode was constructed based on multi-walled carbon nanotubes, MCM48 molecular sieve composite modified glassy carbon electrode .The modified electrode showed that it can be used for simultaneous determination of acetaminophen (ACT) and codeine (COD), simultaneously. The measurements were carried out by the application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. The fabricated sensor revealed some advantages such as excellent selectivity, good stability and high sensitivity toward ACT and COD determination. Application of DPV method under the optimum conditions showed the modified electrode provides linear responses versus ACT concentrations in the range of 0.2-40 µM and 80-350 µM. The results for COD showed the linear responses in the ranges of 4-70 µM and 150-400 µM respectively using DPV method. The modified electrode was used for determination of ACT and COD in real samples like human blood serum and plasma with satisfactory results.
    Keywords: Acetaminophen, Codeine, Multiwalled carbon nanotubes, MCM-48
  • Puttaraju Shankar *, Bhavyashri Shetty, Antony Lazor Jayasheelan, Nanja Reddy Sivasankara Reddy, Challa Seshu Prakash Pages 202-210
    Barium substituted nanocrystalline ferrites with chemical composition BaxCa1-xFe2O4 (x =0.0 to 0.25) BCAF were prepared by solution combustion method. The phase formation of mixed spinal structured ferrites was confirmed by PXRD analysis. The average crystallite size was calculated using Debye-Scherrer formula and it was found to be in the range of 27-44 nm. Surface morphology was analyzed by SEM, it reveals the highly porous nature of the synthesized samples. Nanocrystalline nature of samples was confirmed by TEM. The real and imaginary part of dielectric constant (ε′ & ε′′), dielectric loss factor (tan δ) and AC conductivity (σac) of the samples were measured using LCR meter in the frequency range of 100 Hz–5 MHz at room temperature. The dielectric constant of the synthesized ferrite samples was found to decrease with increase in frequency and finally reaches a constant value at higher frequencies which is typical behavior of dielectric ferrites. The observed dielectric dispersion is of Maxwell-Wagner type interfacial polarization. The contribution of grain boundary resistance has been studied from the cole-cole plots. The impedance spectroscopy analysis confirms the non-Debye type of conductivity relaxation for the nanocomposite. The high value of the dielectric constant makes the material suitable for miniature memory devices based capacitive components or energy storage devices. The samples also show low dielectric losses at high-frequency region which make them suitable for high-frequency applications and also long relaxation time of BCAF nanocomposites could make them suitable for nano scale spintronic devices.
    Keywords: Barium calcium ferrite, complex Impedance spectroscopy Dielectric properties, Electric modulus, Nano-ferrites
  • Ahmad Gholizadeh, Saeid Jamehbozorgi, Mohammad Yousefi *, Ali Niazi Pages 211-218
    In this study, Flake-like magnesium hydroxide (Mg(OH)2) and cubic-like aluminum hydroxide (Al(OH)3) nanostructures were synthesized via a simple co-precipitation method at relatively low temperature. Chemical properties and surface morphology of the magnesium hydroxide and aluminum hydroxide were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy image (SEM), transmission electron microscopy image (TEM), differential scanning calorimetery analysis (DSC) and thermo gravimetric analysis (TGA). Magnesium hydroxide and cubic-like aluminum hydroxide were then added to PVC, Graphite and PMMA polymers. The effect of cooperation between magnesium hydroxide and cubic-like aluminum hydroxide nanostructures on the fire retardant of the polymeric matrixes has been investigated. The results show that the thermal decomposition of the nanocomposites shifts towards higher temperature in the presence of the magnesium hydroxide and cubic-like aluminum hydroxide. As well as, the enhancement of fire retardant of nanocomposites is due to endothermically decomposition of these nanostructures and releases of water and dilutes combustible gases.
    Keywords: Cubic like, Flake- Like, Flame retardant, Nanocomposite
  • Abdolhamid Bamoniri *, Bi Bi Fatemeh Mirjalili, Nahid Yaghmaeiyan, Mahabadi Pages 219-229
    Kaolinite clay found its application in medicine, in toothpaste, in cosmetic and as a food additive. Recently, a specially formulated spray is used in fruit and vegetable production to repel the insects and prevent sunburn. Kaolin-SO3H nanoparticles were prepared via reaction of kaolin and chlorosulfonic acid and characterized by FT-IR, XRD, FESEM, TEM, XRF, EDS, BET and TGA. 2-Substituted benzimidazoles have been used as selective neuro-peptides YY, receptor antagonists, antitumor, antivirus, antimicrobial, antioxidant, antiparasitic, antihelmintics, antiproliferative, anti-HIV, anticonvulsant, anti-inflammatory, antihypertensive, antineoplastic, analgesicand antitrichinellosis, topoisomerase IV inhibitors, potent inhibitors of TiE-2 and VEGFER-2 tyrosine kinase receptor, and 5-HT3 antagonists. 2-Substituted benzimidazoles are prepared via condensation of o-phenylenediamines and aldehydes. In this article, we have used Kaolin-SO3H nanoparticles for the synthesis of 2-substituted benzimidazoles under mild reaction conditions. The structure of products were identified by FT-IR, 1H-NMR and 13C-NMR. This method has the advantages of high yields, short reaction times and easy work-up.
    Keywords: Benzimidazole, Kaolin-SO3H nanoparticles, Solid acid, Heterogeneous catalyst
  • Alireza Razeghizadeh, Maryam Mahmudi Ghalavandi, Farhang Sohili, Vahdat Rafee * Pages 230-237
    In this paper, the RF power change effect on the structural, optical and electrical properties of CuO thin films prepared by RF reactive magnetron sputtering deposited on glass substrates are studied. At first, the thin films are prepared at 150, 280, 310 and 340W respectively. Then, the films are characterized by XRD, AFM, Uv-visible and four-point probe analysis respectively. The results show that the crystallite size and lattice constant of samples increased from about 20 nm to 59 nm and 4.15 to 4.51 respectively with an increase in RF power from 150 to 340W. The AFM and four-point analysis results show that the samples deposited at 150 and 340W have smooth surfaces and more surface electrical resistance than the samples deposited at 280 and 310W because the dominant phase of samples prepared at 150 and 340W are CuO2 and 280 and 310 are CuO respectively. Also, the results indicate the energy band gap increased from about 2.25 to 2.52eV with an increase in RF power from 150 to 340W and the extinction coefficient of samples prepared at 150W is more than samples prepared at 340W in all of the wavelength.
    Keywords: RF Reactive Magnetron sputtering, Copper oxide, AFM, Four-point probe
  • Mitra Amoli Diva *, Kamyar Pourghazi, Majid Amoli Diva Pages 238-248
    Abstract A new adsorbent, ethylene glycol bisthioglycolate modified gold nanoparticles grafted Mn doped Fe3O4 nanoparticles (EGBTG-Au@Mn-Fe3O4 NPs) were synthesized through chemical precipitation followed by an oxidative Mn doping process to use for extraction and preconcentration of trace amounts of Hg, and Cu ions in artificial and natural saliva. The prepared adsorbent was characterized by TEM, BET, XRD and VSM techniques. Fusayama artificial saliva was prepared and used as blank sample and natural saliva was collected from nine volunteers ranged from 15-29 years old who exposed to posterior decayed teeth amalgam filling and short-term release of heavy metal ions was assessed in 24, 72 and 96 h after filling. Various factors affecting extraction/desorption efficiency of target ions have been investigated and analytical characteristics of the recommended method were determined. Detection limits of 0.12 and 0.09 ng mL-1 were obtained for Cu and Hg ions respectively with preconcentration factor of 96. The results revealed that the adsorbent has high adsorbent capacity and good reusability for extraction/preconcentration of target ions in relatively high saline solution like biological fluids.
    Keywords: Mn doped Fe3O4 nanoparticles, Magnetic solid phase extraction, Saliva, Dental amalgam, Cold vapor atomic absorption spectrometry, ICP-OES
  • Mohamad Reza Afifeh, Ali Ahmadpour *, Mohammad Taghi Hamed Mosavian, Ali Ayati, Fatemeh F. Bamoharram, Fatemeh Ahmadi Hekmatikar Pages 249-257
    In the present study, platinum nanoparticles were synthesized through an effective, facile and green method using H14[NaP5W30O110], a Preyssler-structured polyoxometalate, under UV light irradiation. Preyssler plays the roles of photocatalyst, reducing agent and stabilizer in the synthesis of Pt nanoparticles. The effect of different parameters, i.e. time, propan-2-ol volume, pH, molar ratio of Preyssler to Pt ions ([Preyssler]/[Pt4+]) and temperature on the size of prepared nanoparticles were investigated. Under different conditions, platinum nanoparticles with minimum size of 13 nm were ultimately obtained. The nanoparticles were characterized by UV/Vis spectroscopy, particle size distribution, transmission electron microscopy and electron diffraction techniques. The results showed that the photocatalytic behavior of Preyssler was a propulsion factor in reducing the Pt4+ ions. The resultant NPs are covered with a Preyssler layer which contributes to the stabilization of NPs. It was shown that the subsequent increasing of NP size can be on account of partly increasing rate of NP growth compared to nucleation. Moreover, the stability of obtained nanoparticles was inspected.
    Keywords: Green method, Platinum Nanoparticle, Polyoxometalate, Preyssler
  • Farideh Sedighi, Ali Sobhani, Nasab *, Mohsen Behpour, Mehdi Rahimi, Nasrabadi Pages 258-267
    NiMn2O4 nanoparticles have been successfully prepared through sol-gel method. The effects of different factors such as the type of solvent, and amino acid temperature were investigated on the size and morphologies of products. The smallest particle size of NiMn2O4 nanoparticles was found to be 25 nm in diameter. The magnetic properties of the samples were also measured by an alternating gradient force magnetometer (AGFM). The optical property of the desired products was investigated by UV–vis diffuse reflectance spectroscopy , and the band gap of product was computed nearly 3 eV. The estimated band gap confirms that this product may be used as a photocatalyst, so the photocatalytic test was conducted by photooxidation of dyes under ultraviolet irradiation and in the presence of NiMn2O4 nanoparricles. The results demonstrated that rhodamine B degradation was about 98 % under ultraviolet light for 80 min. Therefore, the synthesized product can be employed as an effective photocatalyst.
    Keywords: Nanostructure, NiMn2O4, New approach, Amino acid, photocatalyst
  • Mozhgan Yavari, Mohammad Mazloum, Ardakani *, Alireza Khoshroo Pages 268-275
    Abstract Recently alcohol fuel cells has been increased consideration because of their environmental friendliness, high energy conversion efficiency and low emissions. Many effort have been made to improve the electro-oxidation performance of alcohols such as methanol, ethanol and propanol. In this work, a new method for ethanol oxidation based on core–shell titanium dioxide / carbon nanofibers (TiO2@C NFs), TiO2 as a core and carbon as a shell, decorated Ni nanoparticles (NiNPs) is presented. TiO2@C NFs were prepared by mixing the electrospinning technique and hydrothermal method. Nickel nanoparticles were electrodeposed on the surface of TiO2@C NFs denoted as TiO2@C- Ni. The catalyst was characterized by SEM and electrochemical methods. Performance of ethanol oxidation was investigated in aqueous NaOH solutions by chronoamperometry and cyclic voltammetry. The electrochemical measurements showed that this electrode is effective and has good electrocatalytic activity for ethanol oxidation and the structures of nanofibers have important effect on the electrooxidation of ethanol. The synergy between Ni, carbon shell and TiO2 support, boost ethanol oxidation on TiO2@C- Ni. Keywords: Ethanol electrooxidation; Electrospinning; Nickel nanoparticles; Core–shell titanium dioxide /carbon nanofibers
    Keywords: Ethanol electrooxidation, Electrospinning, Nickel nanoparticles, Core–shell titanium dioxide, carbon nanofibers
  • Siamk Hoseinzadeh *, Amir Hoshang Ramezani Pages 276-286
    In the last decades an important number of research papers published on nano chip electrode and cathode electrochromic materials. Tantalum (Ta) with so high melting point can be as a good candidate for the future of nano chip devices. However, its surface has not enough trap centers and/or occupation states, so nitrogen ions exposed on Ta surafce, may solve this problem. For this purpose, in the present work, samples of tantalum with purities of 99.99% (0.58 mm thickness) were implanted by nitrogen ions. The ions’ implantation process was performed at 30 keV and also at different doses which were in the range between 1017- 1018 ions/cm2. The electrical, nano structural characteristics, sample surface topography characteristic were investigated on Tantalum nitrides (Ta/N) structures by looking at current–voltage (I–V) curves.In addition to Ta/N, WO3powders as a famous EC metal oxide, a silver metal deposited on fluorine doped tin oxide (FTO)-coated glass andmultilayer structure with using the physical vapor deposition (PVD) apparatus are formed. Some techniques such as uv- visible, Atomic Force Microscopy (AFM) and X Ray Diffraction (XRD) have been used. The obtained results show the formation of hexagonal tantalum nitride (TaN0.43), and more trap centers of sample surface (in comparison to current cathode material of EC device). The electrical resistivity of the tantalum after nitrogen implantation is also found to increase with ion doses.Therefore, Ta/N with more trap centers (rough surface) can be suggested as a good element of the future of EC and nano devices.
    Keywords: Nano composite, nano electronic devices, cathode, Tantalum, Ion implantation
  • Gheffar Kheraldeen Kara, Mahboubeh Rabbani * Pages 287-300
    According to the increasing development of the mankind, social and technology activities in the earth, various industry is in a state of uncontrolled growth. In the present study, magnetite/nickel oxide mixed metal oxide nanoparticles (FNMMO NPs) were prepared by a simple method assisted by ultrasonic waves and applied as a novel adsorbent to dispose of dye wastewater. The morphology and chemical structures of the Fe3O4, NiO and FNMMO NPs were characterization by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), energy-dispersive X-ray spectroscopy (EDX), scanning electronic microscope (SEM) and transmission electron microscope (TEM). The adsorption of methylene blue (MB) onto FNMMO NPs was studied in relation to initial concentration of MB, contact time, adsorbent dose and pH value of solution. The equilibrium adsorption isotherm was fitted by Langmuir isotherm. The capacity of adsorption was evaluated 40.1 mg.g-1 and the time required to reach the adsorption equilibrium was 180 min.
    Keywords: Novel adsorbent, Mixed metal oxide, Adsorbent dose, Methylene blue
  • Nafiseh Sabzroo, Tahereh Rohani Bastami *, Majid Karimi, Tahereh Heidari Pages 301-315
    Magnetic poly (acrylonitrile-co-acrylic acid) (PAN-co-AA) composite nanofibers with different proportions of magnetic nanoparticles (MNPs) were fabricated using electrospinning technique. Electrospinning conditions like polymeric concentration, applied voltage, feeding rate, working distance, and collector type were explored and optimized to produce ultrafine- uniform size and bead free nanofibers. Electrospun nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer−Emmett−Teller (BET) isotherms, X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometry (VSM). The optimum electrospinning conditions were obtained to be 12wt% concentration, 20 kV voltages, 20 cm tips to collector distance and 0.5 mL/h flow rate. At the optimal operating condition the nanofibers diameter dropped from 359 nm to 74 nm and the specific surface area increased to 12.09 m2g-1 with respect to MNPs content (0 to 40 wt. %). Also, the magnetic property of magnetic nanofibers facilitated the separation of solid phase much easier than nonmagnetic nanofiber.
    Keywords: Electrospinning, Nanofibers, Poly (acrylonitrile-co-acrylic acid), Magnetic nanoparticle
  • Mehrdad Manteghian *, Abdolhamid Sameni Pages 316-325
    A major portion of BaSO4 is used as drilling fluid additives in the presence of some biopolymers such as starch and PAC (Polyanionic Cellulose) as filtration control and viscosifier. BaSO4 nanoparticle was synthesized in the presence of these applicable polymers with precipitation method by using BaS produced from carbothermal method and Na2SO4. Synthesized nanoparticles size and morphology were analyzed using DLS (Dynamic Light Scattering) and FESEM (Field Emission Scanning Electron Microscope). It can be concluded that, nanoparticles size have inverse proportion with polymer concentration. Also nanoparticles have smaller size in the presence of PAC with longer functional group than starch and prevent chemical reaction due to steric hindrance. If pH increases from 7 to 11, nanoparticles in starch had minimum size in pH=9 and various pH didn’t have noticeable effect on size with PAC. In kinetic study, conductometer is used to detect induction time in different Na2SO4 concentrations and polymers and it is indicated that interfacial tension is decreased as reactant concentration increased and PAC increase induction time and reduce interfacial tension more than starch.
    Keywords: barium sulfate, Nanoparticles, biopolymers, induction time
  • Anil Ramdas Bari *, Prapti Anil Bari, Ramesh Harishchandra Bari Pages 326-330
    Nanostructured ZnO thin films were prepared by sol-gel dip coating technique. Zinc acetate and ammonium hydroxide were used as precursors and ethanol was as solvent. Ammonium hydroxide (NH4OH) solution was added drop-wise under vigorous stirring to obtain the sol-gel of different pH (varying from 6.9 to 7.2). ZnO thin films were obtained by dipping the glass substrates for few seconds and then dried in air at room temperature. This process was repeated for different number of coats for the typical sol. Different numbers of coating cycle was employed to obtain the films with varying thicknesses. These films were annealed at 5000C and were characterized by x-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive analysis of x-rays (EDAX). ZnO thin films obtained from sol-gel dip-coating technique were observed to nanostructured. Average particle size was observed to be smaller than 50 nm. The most of the particles were observed to be spherical in shape. ZnO films were observed to be nonstoichiometric (Zinc deficient) in nature. The results were discussed and interpreted.
    Keywords: Nanostructured ZnO, Thin films, Sol-gel dip coating technique, Grain Size
  • Farideh Sedighi, Ali Sobhani, Nasab, Mahdiyeh Esmaeili, Zare, Mohsen Behpour * Pages 331-339
    A simple co-presipitation method has been developed to synthesize SrWO4 and Ag°-SrWO4 micro/nanostructures with different morphologies, including platelet-, star- and flower-like, in the presence of Na(B(C6H5)) as surfactant. The formation of platelet-, star- and flower-like shapes of particulate system was examined by electron microscopy technique. The products were characterized by X-ray diffraction, scanning electron microscope, UV-vis absorption, energy dispersive X-ray and fourier transform infrared spectra. The scheelite type tetragonal structure of all the synthesized compounds was revealed by powder X-ray diffraction analysis. The influence of surfactant concentration (sodium tetraphenylborate as new surfactant) on the size and morphology of products was investigated. Finally, a good photocatalytic activity was first discovered of the Ag°-SrWO4 microcrystals for the degradation of methyl orange dye after 100 min under UV-vis light. Hence, from the present investigation it was observed that the doping of Ag in SrWO4 will yield a new kind of multifunctional material for fabricating electronic devices.
    Keywords: SrWO4, Surfactant concentration, Photocatalysis, Co-precipitation
  • Ahmed Mohaisen *, Zinah Hamad Pages 340-348
    Nanocomposites films of (polymer blend-ceramics) were prepared from (PVA-PAA) blend and (PVA-PAA) blend doped with niobium carbide nanoparticles for humidity sensors have low cost, easy fabrication, high sensitivity, lightweight and high corrosion resistance. The structural, electrical and optical properties of (PVA-PAA-NbC) nanocomposites have been studied. The D.C electrical properties of (PVA-PAA-NbC) nanocomposites were studied with different temperature range. The results showed that the D.C electrical conductivity (PVA-PAA) blend increases with increase in niobium carbide nanoparticles concentrations and temperatures. The activation energy of (PVA-PAA) blend decreases with increase in niobium carbide nanoparticles concentrations. The results of optical properties showed that the transmittance of (PVA-PAA) blend decreases with increase in niobium carbide nanoparticles concentrations. The (PVA-PAA-NbC) nanocomposites tested for humidity sensors and the results showed that the (PVA-PAA-NbC) nanocomposites have high sensitivity for humidity sensors. Keywords: niobium carbide, nanocomposites, humidity sensors, activation energy.
    Keywords: activation energy, Humidity sensors, Nanocomposites, Niobium Carbide
  • Mohammad Ali Rezvani *, Maryam Shaterian, Nasrin Khalafi Pages 349-364
    To prepare ultra-clean gasoline fuel, a new nanocomposite TBA-PV2Mo10@PVA was introduced as an efficient and green catalyst for oxidative desulfurization (ODS) process. The nanocomposite was successfully prepared by reaction of tetrabutylammonium bromide (TBA), H5PMo10V2O40, and poly vinyl alcohol (PVA) at room temperature via sol–gel method under oil-bath condition. The synthesized TBA-PV2Mo10@PVA was characterized by FT-IR, XRD, UV-vis, SEM and 31P NMR spectroscopy. The catalytic activity of catalyst was tested on the ODS of gasoline in the presence of CH3COOH/H2O2 (1/1 volume ratio) as oxidant system and results were compared with model sulfur compounds (MSCs). After 2 h, the results were shown that the removal of total sulfur content could be reduced to 97% at the temperature of 35 °C. The main factors affecting the desulfurization efficiency, including catalyst dosage and temperature were investigated in detail. In addition, the kinetic parameters of oxidation of MSCs, reaction mechanism, and reusability of catalyst were discussed. The TBA-PV2Mo10@PVA nanocatalyst was separated and reused conveniently at the end of the reaction for five times. The excellent performance of this catalytic oxidation system can be a promising rout to achieve ultra-clean gasoline.
    Keywords: Gasoline, Heterogeneous catalyst, Nanocomposite, Oxidative desulfurization, Polyoxometalate
  • Matin Karbasi, Farnaz Maghazeii *, Davood Ghanbari Pages 365-375
    We synthesized CoFe2O4 nanoparticles using heating in various times by simple microwave method at power about 600W. Water, ethylene glycol and their combination were used as solvent. X-ray diffraction pattern(XRD) analysis was performed for evaluation of structural characterization of samples. We also used scanning electron microscopy (SEM) to evaluate the effects of various parameters of heating time and solvent type on mean grain size and nanostructure of the samples. Our results showed that with changing of these parameters, we can control the nanostructure and grain size of prepared samples. In addition, we produced polymeric nanocomposite of PVA/CoFe2O4 using poly vinyl alcohol films. The thermal stability of it in comparison to PVA polymer was assessed by thermal gravimetric analysis (TGA). Also the nanostructures of polymer nanocomposite were analyzed by SEM. To evaluate the magnetic parameters of samples, vibrating sample magnetometer (VSM) analysis were done. Also the spectrum of synthesized nanoparticles and polymer nanocomposite were drawn by FT-IR. Our results confirmed that the nanostructures, magnetic behavior and thermal stability of the prepared nanocomposite are acceptable for needed applications. Key Words: Cobalt ferrite nanoparticles, Magnetic behavior, Nanostructure, Polymer nanocomposite, Thermal stability
    Keywords: Cobalt ferrite nanoparticles, Magnetic behavior, Nanostructure, Polymer nanocomposite, Thermal stability
  • Tahira Akther, S Priya, Saroj Kumar Sah, Mohd Shahanbaj Khan, S Hemalatha * Pages 376-383
    An easy and rapid microwave-assisted green synthesis of silver nanoparticles (AgNPs) was carried out using aqueous bark extract of arjuna and their antibacterial and anti-biofilm potential was investigated. The AgNPs were characterized by various techniques .The FTIR data revealed the presence of plant organic constituents and metabolites bound to TA-AgNPs, which contributes for their stability. To elucidate the antibacterial efficacy and biofilm inhibition of Ta-AgNps against multidrug-resistant. Pathogenic E.coli harbouring the ESBLs. Treatment of TA-AgNps inhibited the growth of human pathogenic (both gram positive and gram negative) bacterial strains including Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Salmonella typhimurium (ATCC 14028), Proteus mirabilis (ATCC 35659), Acinetobacter baumannii (ATCC 19606) and Methicillin-Resistant Staphylococcus Aureus (MRSA). Further, the clinical isolates of E.coli that are resistant and susceptible to antibiotics are utilized to test the efficacy of TA-AgNps. In E.coli, ESBLS are responsible for antibiotic resistance. Moreover, docking study with T.arjuna phytochemical constituents confirmed that the phytochemical constituents present in TA-AgNPs interacted well with CTXM-15 and highest interaction was observed with tannic acid. Hence the expression of gene encoding CTXM-15 was screened in clinical isolates. Interestingly, the expression of CTXM-15 was not observed in samples treated with TA-AgNps. The results suggested that AgNPs of Terminalia arjuna bark extract can be used to control multidrug-resistant E.coli to prevent the antibiotic resistance. To the best of our knowledge, this is the first attempted study to show the effectiveness of Ta-AgNps against multidrug-resistant E.coli harbouring CTXM-15.
    Keywords: T.arjuna, Phytochemical screening, Antioxidant activity, Antibacterial Activity
  • Sheida Sarafraz, Hossain, Ali Rafiee, Pour *, Maryam Khayatkashani, Asa Ebrahimi Pages 384-395
    Gallic acid (GA) is the main phenolic antioxidant which has been subjected of many studies because of its important biological properties including anticancer, anti-inflammatory and antimicrobial activities as well as free radicals scavenger and cardiovascular diseases protector. Hereupon, fabricating a selective and sensitive sensor for GA detection and measurement is an important issue. In this paper a carboxylated MWCNTs modified carbon paste electrode (MWCNTs-COOH/CPE) was successfully fabricated and employed for GA determination. Activating the carboxylic sites of the MWCNTs carried out in nitric acid solution in ultrasonic bath and further studied by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The electrocatalytic oxidation of GA at the MWCNTs-COOH/CPE surface was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The GA presented a high electrochemical response on MWCNTs-COOH/CPE at pH 2 in comparison with the CPE. This sensor showed a linear response range of 0.33 - 196 µM and detection limit of 17.2 nM (S/N = 3). Furthermore, the designed MWCNTs-COOH/CPE was successfully applied as a electrochemical sensing system for GA determination in extracts of Camellia sinensis, Viola odorata L, Commiphora mukul, and Vitex agnus-castus respectively with estimated amount of 11.4, 8.9, 11.91 and 2.9 mg L-1 GA in each extract.
    Keywords: Carbon paste electrode, Electrochemical sensor, Gallic acid, Antioxidant Capacity, Multiwalled carbon nanotubes, Plants extracts