Search for: silver-nanoparticle
0.007 seconds
Total 117 records

    Nanodiamond Decorated with Silver Nanoparticles as a Sensitive Film Modifier in a Jeweled Electrochemical Sensor: Application to Voltammetric Determination of Thioridazine

    , Article Electroanalysis ; Volume 25, Issue 2 , 2013 , Pages 417-425 ; 10400397 (ISSN) Shahrokhian, S ; Hosseini Nassab, N ; Sharif University of Technology
    Nanodiamond-graphite (NDG) decorated with Ag nanoparticles (AgNPs-NDG) was prepared and used to construct a novel sensitive sensor for the voltammetric determination of thioridazine (TR). The results indicate a remarkable increase in the oxidation peak currents together with a negative shift in the oxidation peak potentials, in comparison to the bare pyrolytic graphite electrode. Remarkable enhancement in microscopic area of the electrode along with strong adsorption of TR on the surface of the modified electrode resulted in a considerable increase in the peak current of TR. The surface morphology and the nature of the composite film deposited on PGE were characterized by scanning electron... 

    Optical detection of some hydrazine compounds based on the surface plasmon resonance band of silver nanoparticles

    , Article Spectroscopy Letters ; Volume 46, Issue 1 , 2013 , Pages 73-80 ; 00387010 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Fotovat, M ; Sharif University of Technology
    An indirect colorimetric method is presented for spectrophotometric determination of hydrazine, phenylhydrazine, and isoniazid. Reduction of silver ions to silver nanoparticles (AgNPs) by these analytes as active reducing agents in the presence of polyvinylpyrrolidone (PVP) and also cetyltrimethylammonium chloride (CTAC) as a stabilizer is the basis of the proposed method. The changes in plasmon absorbance of the AgNPs at λ = 415 nm in the presence of PVP were proportional to concentration of hydrazine, phenylhydrazine, and isoniazid in the ranges of 4.0-150.0 μM, 1.0-55.0 μM, and 2.0-30.0 μM, respectively, and the detection limit obtained was 0.79 μM. In the presence of CTAC, the linear... 

    Sensitive spectrophotometric detection of dopamine, levodopa and adrenaline using surface plasmon resonance band of silver nanoparticles

    , Article Journal of the Iranian Chemical Society ; Volume 7, Issue SUPPL. 1 , 2010 , Pages S83-S91 ; 1735207X (ISSN) Hormozi Nezhad, M. R ; Tashkhourian, J ; Khodaveisi, J ; Sharif University of Technology
    A simple and effective procedure is proposed for spectrophotometric determination of catecholamines; Dopamine (1), L-Dopa (2) and Adrenaline (3). It was found that the reduction of Ag+ to silver nanoparticles (Ag-NPs) by these catecholamines in the presence of polyvinylpyrrolidone (PVP) as a stabilizing agent produced very intense surface plasmon resonance peak of Ag-NPs. The plasmon absorbance of the Ag-NPs allows the quantitative spectrophotometric detection of the catecholamines. The calibration curves derived from the changes in absorbance at λ = 440 nm were linear with concentration of Dopamine, Levodopa and Adrenaline in the range of 3.2×10-6- 2.0x10-5 M, 1.6x10-7 - 1.0×10-5 M,... 

    Modification of the electrode surface by ag nanoparticles decorated nano diamond-graphite for voltammetric determination of ceftizoxime

    , Article Electroanalysis ; Volume 28, Issue 3 , 2016 , Pages 469-476 ; 10400397 (ISSN) Shahrokhian, S ; Ranjbar, S ; Ghalkhani, M ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    A modified glassy carbon electrode with a film of nano diamond-graphite nano mixture decorated with Ag nanoparticles (AgNPs-NDG/GCE) was constructed and used for sensitive voltammetric determination of ceftizoxime (CFX). Morphology of AgNPs-NDG/GCE has been examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental variables such as deposited amount of the modifier suspension, pH of the supporting electrolyte and accumulation potential and time were optimized by monitoring of CV and LSV responses of CFX. The results illustrate that AgNPs-NDG/GCE exhibits an excellent electrocatalytic effect in the electro-oxidation of CFX that leads to a considerable... 

    Efflux pump inhibitory activity of biologically synthesized silver nanoparticles against multidrug-resistant Acinetobacter baumannii clinical isolates

    , Article Journal of Basic Microbiology ; Volume 60, Issue 6 , 2020 , Pages 494-507 Behdad, R ; Pargol, M ; Mirzaie, A ; Karizi, S. Z ; Noorbazargan, H ; Akbarzadeh, I ; Sharif University of Technology
    Wiley-VCH Verlag  2020
    This study was carried out to investigate the possible efflux pump inhibitory activity of biologically synthesized silver nanoparticles (AgNPs) against multidrug-resistant (MDR) Acinetobacter baumannii isolates. In this study, the physicochemical characteristics of synthesized AgNPs were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometer (FTIR) methods. Subsequently, MDR A. baumannii isolates were recovered from clinical samples and the phenotypic cartwheel efflux assay and polymerase chain reaction (PCR) were used to elucidate the possible presence of efflux pump in MDR... 

    Silver Nanowaste Reduction and Recycling by Combination of Physical and Chemical Seperation Methods

    , M.Sc. Thesis Sharif University of Technology Sabetghadam, Afzal (Author) ; Hormozi Nezhad, Mohammad Reza (Supervisor) ; Sajjadi, Ali Akbar (Supervisor)
    The increasing utilization of silver nanoparticles (Ag-NPs) in industrial and consumer products has raised concern to wastewater treatment utilities, due to its antimicrobial activity. In this research, recovery of silver nanoparticles from wastewater via using activated carbon and convert it into usable nanoparticles is presented. real waste of silver nanoparticles have been used and activated carbon as adsorbent has a high absorption recovery for silver. Under the optimized experimental parameters e.g. pH, temperature, time of process, and amount of activated carbon, an absorption maximum was achieved and over than 99% of silver nanoparticles can be removed from wastewater. After the... 

    Biopolymers Mediated Green Synthesis of Silver Nanoparticles With Definite Shape and Their Biomedical Activity Investigation

    , M.Sc. Thesis Sharif University of Technology Soleyman, Rouhollah (Author) ; Pourjavadi, Ali (Supervisor)
    Silver nanoparticles (Ag-NPs) are promising agents in bionanotechnology, because of their unique activity against unfavorable processes in bioscience such as undesirable microbial growth, angiogenesis in tumors and etc. Ag-NPs have been widely used in wound dressing; wound healing, water treatment filters, inks, sensors, catalysts, cosmetics, orthopaedics, surgical instruments and vascular prosthesis. Ever-increasing applications of Ag-NPs in biomedical field are due to the anti-bacterial, anti-fungal, anti-viral, anti-platelet, anti-proliferative, anti-inflammatory (apoptosis detection) and anti-angiogenesis properties (cancer therapy). In the current research, we synthesized Ag-NPs in... 

    Synthesis of Colloidal Silver Nanoparticles by Microwave Method and Study of its Antibacterial Activity

    , M.Sc. Thesis Sharif University of Technology Abtahi, Nikoo (Author) ; Dolati, Abolghasem (Supervisor)
    Silver nanoparticles are widely used in different industries because of their antibacterial effects. Many synthesis methods were used to obtain silver nanoparticles. In this study the microwave method is used to synthesize nanosilver. This method is easier and faster in comparison to other methods. The effect of precursors’ concentrations, using different solvents, different remaining time in microwave and microwave power were studied. By increasing the reaction time, microwave power and using different solvents, nanosilver particle size varies from 2 nm up to 300nm. The TEM images, size distribution, XRD patterns and UV-visible spectrum are shown. The obtained nanosilver was used to observe... 

    An Investigation on the Effects of Experimental Variables on Silver Nano Particles Produced by Electromagnetic Levitation Technique

    , Article Journal of Cluster Science ; Volume 24, Issue 3 , 2013 , Pages 635-642 ; 10407278 (ISSN) Halali, M ; Malekzadeh, M ; Sharif University of Technology
    In this study the effects of melt temperature and flow rate of cooling gas on the characteristics of silver nanoparticles have been studied. Transmission electron microscopy and dynamic light scattering techniques have been employed to monitor morphology and particle size of the product. Measurements reveal that higher melt temperatures and higher cooling gas flow rates can decrease particle size. Silver nanoparticles with an average particle size of 35 nm and specific surface of 18.489 m2/g have been obtained at a melt temperature of 1,130 °C with argon flow rate of 20 liters per minute  

    Microextraction of antidepressant drugs into syringes packed with a nanocomposite consisting of polydopamine, silver nanoparticles and polypyrrole

    , Article Microchimica Acta ; Volume 183, Issue 1 , 2016 , Pages 195-202 ; 00263672 (ISSN) Bagheri, H ; Bani Hashemi, S ; Zandian, F. K ; Sharif University of Technology
    Springer-Verlag Wien 
    We describe a nanocomposite prepared from polydopamine, silver nanoparticles, and polypyrrole (PDA-Ag-PPy) that can be used for the microextraction in packed syringe (MEPS) of tricyclic antidepressants from urine samples. The PDA-Ag-PPy composite was prepared in-situ by the reduction of silver ion - doped PPy during oxidative polymerization of dopamine. The PDA-Ag coatings on the nanoribbon – shaped PPy represent a highly porous, inorganic–organic hybrid nanomaterial that has a wide range of applications. The nanocomposite was characterized by FTIR and scanning electron microscopy. It is shown to be an efficient sorbent for the MEPS of the tricyclic antidepressants amitriptyline, imipramine... 

    Comparative study of antibacterial inhibitory effect of silver nanoparticles and garlic oil nanoemulsion with their combination

    , Article Biointerface Research in Applied Chemistry ; Volume 9, Issue 6 , 2019 ; 20695837 (ISSN) Keshvadi, M ; Karimi, F ; Valizadeh, S ; Valizadeh, A ; Sharif University of Technology
    AMG Transcend Association  2019
    Silver can inhibit bacterial activity. Previous studies showed that high concentration of silver nanoparticles (AgNPs) in compared to its lower concentrations is toxic for human health. However, by decreasing concentration of AgNPs, antibacterial activity also decreases. In this study, we investigated synergistic inhibitory activity of the combination of AgNPs and garlic oil nanoemulsion (GONE) for increase antibacterial activity of AgNPs at lower concentrations. AgNPs and GONE with sizes of 30.7 and 19.3 nm were synthesized and prepared by chemical reduction and low energy method, respectively. Physicochemical properties of AgNPs and GONE were investigated. The minimum inhibitory... 

    Stability, size and optical properties of silver nanoparticles prepared by laser ablation in different carrier media

    , Article Applied Physics A: Materials Science and Processing ; Volume 84, Issue 1-2 , 2006 , Pages 215-219 ; 09478396 (ISSN) Tilaki, R. M ; Irajizad, A ; Mahdavi, S. M ; Sharif University of Technology
    We studied the effects of the surrounding liquid environment on the size and optical properties of silver nanoparticles prepared by laser ablation by a pulsed Nd:YAG laser operated at 1.064 nm. The silver targets used were kept in acetone, water and ethanol. TEM observations and optical extinction were employed for characterization of particle size, shape and optical properties, respectively. Nano silver in acetone showed a narrow size distribution with a mean size of 5 nm and the colloidal solution was stable. In deionised water a rather narrow size distribution with a mean size of 13 nm was observed and nanoparticles were precipitated slowly after about two weeks. In ethanol, a broadening... 

    Synthesis of γ-Fe2O3 Nanoparticles by Gelatin Mediator and Synthesis of γ-Fe2O3/SiO2/PCA/Ag-NPs Nanostructure Drug Delivery System

    , M.Sc. Thesis Sharif University of Technology Masoud, Nazila (Author) ; Pourjavadi, Ali (Supervisor)
    Maghemite (γ-Fe2O3) nanoparticles were produced after high temperature oxidation of gelatin-Fe3O4 nanocomposite, obtained from a common coprecipitation process of Fe2+ and Fe3+ ions in an alkaline medium in the presence of a gelatin protein as an effective mediator. Size, shape, surface morphology and magnetic properties of the prepared γ-Fe2O3 nanoparticles were characterized using XRD, FTIR, TEM, SEM and VSM data. The results revealed that primary, gelatin-Fe3O4 nanocomposite had been formed and next, the gelatin decomposition in furnace produced a spinel structure of γ-Fe2O3. The effects of furnace temperature and time of heating together with the amount of gelatin on the produced... 

    Separation of Olefins from Paraffins Using Nanocomposite Polymeric Membranes

    , M.Sc. Thesis Sharif University of Technology Karami, Meysam (Author) ; Soltanieh, Mohammad (Supervisor) ; Goodarznia, Iraj (Supervisor)
    In this study, fabrication of polymeric nanocomposite membranes for separation of olefins from paraffins was investigated. Silver nanoparticles were prepared by Polyol chemical reduction method. At first, dense ethylcellulose and ethylcellulose-silver nanoparticles membranes were fabricated by solvent-evaporation method. Then Asymmetric EC and EC-silver nanoparticle nanocomposite membranes were fabricated by dry/wet phase inversion method as a means to improve flux rates and olefin selectivity in olefin/paraffin separations. The membranes properties and The Effects of incorporating nanoparticles in polymer matrix in low concentration on gas permeability and membranes morphology were... 

    Synthesis of Graphene-Based Magnetic Nanocatalyst Supported Ag Nanoparticles for Alcohols Oxidation

    , M.Sc. Thesis Sharif University of Technology Ataei Kachouei, Shiva (Author) ; Mahmoodi Hashemi, Mohammad (Supervisor)
    In this thesis the graphene-based magnetic nanocatalyst was synthesized. The surface of this catalyst was cavered by silica and AgNPs. In addithion of simple sepration by magnetbar, yeild of reaction was promoted by surface modification. Catalyst structure was verified by transmission electron microscopy , scanning electron microscope, fourier transform infrared spectroscopy, X-ray diffraction and Energy dispersive spectroscopy.At the end catalytic activity was examined by oxidation reaction in persense of different alcohols. The oxidation of benzylic alcohol with electron withdrawing substituents was more difficult and the yield was lower, but electron donor substituents effect positively... 

    Construction of Scaffold by Electrospinning Method for Use in Skin Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Heidari Forushani, Parisa (Author) ; Alemzadeh, Iran (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
    Making artificial skin and skin alternatives is one of the most important areas in tissue engineering. Although much progress has been made so far, there is still no definitive cure for second- and third-degree burns. To create new tissue in the body, a suitable substrate for cells is needed, which is called scaffolding, and an ideal scaffold in tissue engineering should mimic the dimensions of extracellular matrix, and nanofibers seem to be the best option for this purpose. Among the methods of manufacturing of nanofibers, electrospun is very easy and accurate method. In previous studies, many natural and synthetic polymers such as chitosan, alginate, collagen, polyathylene oxide, etc.... 

    Synthesis and Characterization of Silver/Poly (Lactic Acid) Nanocomposite and Effect of Gamma Ray

    , M.Sc. Thesis Sharif University of Technology Golestani, Maryam (Author) ; Forounchi, Massoud (Supervisor) ; Dadbin, Susan (Supervisor)
    Nanocomposites of PLA/Ag, PLA/PEG/Ag and PLA/PEG/Oleic acid were synthesized via chemical reduction of AgNO3.The formation of nano-silver particles (Ag-NPs) started in the aqueous phase (using NaBH4 as a reducing agent) followed by transfer of the silver nanoparticles into the organic phase (PLA solution in chloroform) due to the presence of van der waals interactions between the hydroxyl groups of the PLA and the particles charges surrounded in the surface of the Ag-NPs. The nanocomposites films were prepared by the solution casting method. The XRD patterns and UV-Vis spectra of the nanocomposites demonstrated face–centered cubic (fcc) silver crystals and spherical nanoparticles... 

    Study of Some Effective Parameters on Uv Curable Coating Containing Nano Silver

    , M.Sc. Thesis Sharif University of Technology Labbani Motlagh, Akram (Author) ; Mahmoodi Hashemi, Mohammed (Supervisor) ; Bastani, Saeed (Co-Advisor)
    Antibacterial coatings are a branch of paints and coatings industry that has a wide application from Clothing and Textiles to Floor and Medical instrument. Different antibacterial agents such as silver, titanium dioxide, zinc oxide, gold, chitosan, Silicon dioxide, Magnesium hydroxide and carbon nanotubes have been used. UV curable coatings are economic and environmentally friendly coatings and they are one of the fastest growing segments in the paint and coatings industry. Many studies have been conducted on UV curable coatings and their properties. Among different resins, The UV curable polyurethane offer properties such as: Excellent hardness, High gloss, good chemical and weather... 

    Synthesis of Silver Based Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Jelvani Esfahani, Samaneh (Author) ; Bagheri, Habib (Supervisor)
    Recently, conductive nanocomposites have found great deals of attentions due to their vast applications in different fields. According to the definition of nanocomposite, the filler component should be in the range of 10-100 nm. In this study, silver nanoparticles was used as filler with 4 nm size and synthesized by microemulsion method that is known as the best approach for fabricating silver nanoparticles with small sizes, narrow size distribution and high stability.
    Copoly (ortho-phenylenediamine/dopamine) was used as matrix component. Ortho-phenylenediamine is one of the conductive polymers that was used less than other conductive polymers such as polyaniline in this research area.... 

    Comparing Effects of Natural Antibiotics and Anti Bacterial Materials in Burn Wound Infections with Nanoparticles and Skin Scaffold

    , M.Sc. Thesis Sharif University of Technology Ramezani, Bita (Author) ; Alemzadeh, Iran (Supervisor) ; Vosoughi, Manouchehr (Supervisor)
    Burns are one of the most important accidents related to human health. Due to the intense physical and mental complications and high fatality rate associated with them, receiving proper treatment is of paramount importance. The control of infection in wounds would cure and eliminates the effect of wounds and treatment of skin lesions with engineered scaffolds can be an effective method. The purpose of this project is proposing a hydrogel scaffold based on natural polymers of oxidized alginate and gelatin loaded with an herbal drug to control infection and treat burn wounds. For this purpose, the Iranian Oak extract that it's main content is Tanin and PolyPhenolinc materials, was prepared and...