Search for: narrow-size-distributions
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    Synthesis and characterization of pure metallic titanium nanoparticles by an electromagnetic levitation melting gas condensation method

    , Article RSC Advances ; Vol. 4, issue. 14 , 2014 , pp. 7104-7108 ; ISSN: 20462069 Mohammadi, A. V ; Halali, M ; Sharif University of Technology
    Pure titanium nanoparticles were synthesized by utilizing an Electromagnetic Levitation Melting Gas Condensation (ELM-GC) method. Pure bulk titanium samples were melted and evaporated by electromagnetic levitation technique in an inert gas atmosphere in a silica tube. Titanium nanoparticles were formed from ascending vapor by employing high purity argon and helium as carrier gases and cooling agents. Particle size and morphology of the produced nanoparticles were studied by Field-Emission Scanning Electron Microscopy (FE-SEM) and Dynamic Light Scattering (DLS) analysis. Results showed almost spherical nanoparticles with a narrow size distribution under both cooling atmospheres. The purity of... 

    The improvement of light scattering of dye-sensitized solar cells aided by a new dandelion-like TiO2 nanostructures

    , Article Solar Energy Materials and Solar Cells ; Volume 137 , 2015 , Pages 113-123 ; 09270248 (ISSN) Musavi Gharavi, P. S ; Mohammadi, M. R ; Sharif University of Technology
    Elsevier  2015
    We present a new dandelion-like TiO2 spheres by a modified hydrothermal method for manufacture of dye-sensitized solar cells (DSSCs). This construct is composed of numerous nanowires for employment as the scattering layer of DSSCs. Such morphology is produced by nucleation-growth-assembly mechanism. The size of the dandelion-like spheres and their morphology can be tailored by controlling the processing parameters of the modified hydrothermal process. TiO2 nanoparticles with narrow size distribution are also synthesized by hydrothermal route for the active layer of DSSCs. The nanoparticles show pure anatase phase with average size of 40 nm, whereas the dandelion-like TiO2 spheres are pure... 

    Production of silver nanoparticles by electromagnetic levitation gas condensation

    , Article Chemical Engineering Journal ; Volume 168, Issue 1 , March , 2011 , Pages 441-445 ; 13858947 (ISSN) Malekzadeh, M ; Halali, M ; Sharif University of Technology
    Electromagnetic levitation gas condensation (ELGC) method was used to synthesize silver nanoparticles (NPs). Silver droplets were melted and levitated stably at about 1130°C with appropriate flat coils in a 10mm OD silica tube. High purity argon, nitrogen and helium were employed as carrier gases and cooling media. Morphology and particle size of the products were investigated by scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX) and dynamic light scattering (DLS). The DLS, SEM and TEM studies demonstrated narrow size distribution of spherical shape silver NPs with mean particle size of about 60, 50 and 30nm... 

    Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells

    , Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) Tavakoli, M. M ; Simchi, A ; Aashuri, H ; Sharif University of Technology
    Elsevier Ltd  2015
    Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,... 

    Rapid and efficient synthesis of colloidal gold nanoparticles by arc discharge method

    , Article Applied Physics A: Materials Science and Processing ; Volume 96, Issue 2 , 2009 , Pages 423-428 ; 09478396 (ISSN) Ashkarran, A. A ; Iraji zad, A ; Mahdavi, M ; Ahadian, M. M ; Hormozi nezhad, M. R ; Sharif University of Technology
    We report a simple, inexpensive and one-step synthesis route of colloidal gold nanoparticles using arc discharge between titanium electrodes in HAuCl 4 solution achieving long-time stability. Gold nanoparticles of 8 nm diameter were formed during reduction of HAuCl4 in the plasma discharge zone. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Optical absorption spectroscopy of as prepared samples at 15 A arc current in HAuCl4 solution shows a surface plasmon resonance around 550 nm. It was found that sodium citrate acts as a stabilizer and surface capping agent of the colloidal... 

    Antibacterial activity of ultra-small copper oxide (II) nanoparticles synthesized by mechanochemical processing against S. aureus and E. coli

    , Article Materials Science and Engineering C ; Volume 105 , 2019 ; 09284931 (ISSN) Moniri Javadhesari, S ; Alipour, S ; Mohammadnejad, S ; Akbarpour, M. R ; Sharif University of Technology
    Elsevier Ltd  2019
    In this paper, ultra-small CuO nanoparticles (NPs) were synthesized through a mechanochemical method using two different Cu-containing precursors (i.e. CuSO4·5H2O and CuCl2·2H2O), and their structure and antibacterial activity were studied. From the microstructural studies, it was observed that CuO NPs have a spherical morphology and a narrow size distribution with 7 and 14 nm median particle sizes for CuCl2·2H2O and CuSO4.5H2O precursors, respectively. The CuCl2·2H2O derived nanoparticles showed more antibacterial activity than CuSO4.5H2O derived nanoparticles. The minimum inhibitory concentration (MIC) of the synthesized nanoparticles (derived from both precursors) against E. coli and... 

    A new approach for the in vitro identification of the cytotoxicity of superparamagnetic iron oxide nanoparticles

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 75, Issue 1 , 2010 , Pages 300-309 ; 09277765 (ISSN) Mahmoudi, M ; Simchi, A ; Imani, M ; Shokrgozar, M. A ; Milani, A. S ; Häfeli, U. O ; Stroeve, P ; Sharif University of Technology
    Superparamagnetic iron oxide nanoparticles (SPIONs) are increasingly used in medical applications, such as targeting delivery and imaging. In the future, patients are more likely to be exposed to pharmaceutical products containing such particles. The study of toxicity of SPIONs has become of great importance in recent years, although the published data in this arena is limited. The aim of the present work is to investigate the cytotoxicity of SPIONs and the effect of the particles on the cell medium components. For this purpose, uncoated and polyvinyl alcohol (PVA) coated SPIONs with narrow size distribution were synthesized via a well-known coprecipitation method. The mouse fibroblast cell... 

    Optimal design and characterization of superparamagnetic iron oxide nanoparticles coated with polyvinyl alcohol for targeted delivery and imaging

    , Article Journal of Physical Chemistry B ; Volume 112, Issue 46 , 2008 , Pages 14470-14481 ; 15206106 (ISSN) Mahmoudi, M ; Simchi, A ; Imani, M ; Milani, A. S ; Stroeve, P ; Sharif University of Technology
    American Chemical Society  2008
    Superparamagnetic iron oxide nanoparticles (SPION) with narrow size distribution and stabilized by polyvinyl alcohol (PVA) were synthesized. The particles were prepared by a coprecipitation technique using ferric and ferrous salts with a molar Fe3+/Fe2+ ratio of 2. Using a design of experiments (DOE) approach, the effect of different synthesis parameters (stirring rate and base molarity) on the structure, morphology, saturation magnetization, purity, size, and size distribution of the synthesized magnetite nanoparticles was studied by various analysis techniques including X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) with differential scanning calorimetry (DSC)... 

    Design of pH-responsive nanoparticles of terpolymer of poly(methacrylic acid), polysorbate 80 and starch for delivery of doxorubicin

    , Article Colloids and Surfaces B: Biointerfaces ; Volume 101 , January , 2013 , Pages 405-413 ; 09277765 (ISSN) Shalviri, A ; Chan, H. K ; Raval, G ; Abdekhodaie, M. J ; Liu, Q ; Heerklotz, H ; Wu, X. Y ; Sharif University of Technology
    This work focused on the design of new pH-responsive nanoparticles for controlled delivery of anticancer drug doxorubicin (Dox). Nanoparticles of poly(methacrylic acid)-polysorbate 80-grafted starch (PMAA-PS 80-g-St) were synthesized by using a one-pot method that enabled simultaneous grafting of PMAA and PS 80 onto starch and nanoparticle formation in an aqueous medium. The particles were characterized by FTIR, 1H NMR, TEM, DLS, and potentiometric titration. Dox loading and in vitro release from the nanoparticles were investigated. The FTIR and 1H NMR confirmed the chemical composition of the graft terpolymer. The nanoparticles were relatively spherical with narrow size distribution and... 

    Cell toxicity of superparamagnetic iron oxide nanoparticles

    , Article Journal of Colloid and Interface Science ; Volume 336, Issue 2 , 2009 , Pages 510-518 ; 00219797 (ISSN) Mahmoudi, M ; Simchi, A ; Milani, A. S ; Stroeve, P ; Sharif University of Technology
    The performance of nanoparticles for biomedical applications is often assessed by their narrow size distribution, suitable magnetic saturation and low toxicity effects. In this work, superparamagnetic iron oxide nanoparticles (SPIONs) with different size, shape and saturation magnetization levels were synthesized via a co-precipitation technique using ferrous salts with a Fe3+/Fe2+ mole ratio equal to 2. A parametric study is conducted, based on a uniform design-of-experiments methodology and a critical polymer/iron mass ratio (r-ratio) for obtaining SPION with narrow size distribution, suitable magnetic saturation, and optimum biocompatibility is identified. Polyvinyl alcohol (PVA) has been... 

    An in vitro study of bare and poly(ethylene glycol)-co-fumarate-coated superparamagnetic iron oxide nanoparticles: A new toxicity identification procedure

    , Article Nanotechnology ; Volume 20, Issue 22 , 2009 ; 09574484 (ISSN) Mahmoudi, M ; Simchi, A ; Imani, M ; Milani, A. S ; Stroeve, P ; Sharif University of Technology
    As the use of superparamagnetic iron oxide nanoparticles (SPION) in biomedical applications increases (e.g. for targeting drug delivery and imaging), patients are likely to be exposed to products containing SPION. Despite their high biomedical importance, toxicity data for SPION are limited to date. The aim of this study is to investigate the cytotoxicity of SPION and its ability to change cell medium components. Bare and poly(ethylene glycol)-co-fumarate (PEGF)-coated SPION with narrow size distributions were synthesized. The particles were prepared by co-precipitation using ferric and ferrous salts with a molar Fe3+/Fe2+ ratio of 2. Dulbecco's modified Eagle's medium (DMEM) and primary...