Search for: magnetite-nanoparticle
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    Avrami behavior of magnetite nanoparticles formation in co-precipitation process

    , Article Journal of Mining and Metallurgy, Section B: Metallurgy ; Volume 47, Issue 2 , 2011 , Pages 211-218 ; 14505339 (ISSN) Ahmadi, R ; Hosseini, H. M. R ; Masoudi, A ; Sharif University of Technology
    In this work, magnetite nanoparticles (mean particle size about 20 nm) were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS) instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles  

    A new approach for calculation of relaxation time and magnetic anisotropy of ferrofluids containing superparmagnetic nanoparticles

    , Article Journal of Mining and Metallurgy, Section B: Metallurgy ; Volume 48, Issue 1 , 2012 , Pages 81-88 ; 14505339 (ISSN) Ahmadi, R ; Hosseini, H. R. M ; Sharif University of Technology
    In this work, a new approach is described for the calculation of the relaxation time and magnetic anisotropy energy of magnetic nanoparticles. Ferrofluids containing monodispersed magnetite nanoparticles were synthesized via hydrothermal method and then heated using the 10 kA/m external AC magnetic fields in three different frequencies: 10, 50 and 100 kHz. By measuring the temperature variations during the application of the magnetic field, the total magnetic time constant including both Brownian and Neel relaxation times can be calculated. By measuring the magnetic core size and hydrodynamic size of particles, the magnetic anisotropy can be calculated too. Synthesized ferrofluids were... 

    Targeted pulmonary drug delivery in coronavirus disease (COVID-19) therapy: A patient-specific in silico study based on magnetic nanoparticles-coated microcarriers adhesion

    , Article International Journal of Pharmaceutics ; Volume 609 , 2021 ; 03785173 (ISSN) Ebrahimi, S ; Shamloo, A ; Alishiri, M ; Mozhdehbakhsh Mofrad, Y ; Akherati, F ; Sharif University of Technology
    Elsevier B.V  2021
    Since the beginning of the COVID-19 pandemic, nearly most confirmed cases develop respiratory syndromes. Using targeted drug delivery by microcarriers is one of the most important noteworthy methods for delivering drugs to the involved bronchi. This study aims to investigate the performance of a drug delivery that applies microcarriers to each branch of the lung under the influence of a magnetic field. The results show that by changing the inlet velocity from constant to pulsatile, the drug delivery performance to the lungs increases by ∼31%. For transferring the microcarriers to the right side branches (LUL and LLL), placing the magnet at zero height and ∼30° angle yields the best outcome.... 

    Microemulsion Synthesize of Fe3O4/TiO2 Core-Shell Nanoparticles

    , M.Sc. Thesis Sharif University of Technology Sonbolestan, Hosein (Author) ; Madaah Hoseini, Hamid Reza (Supervisor)
    In this study magnetite nanoparticles were synthesized by microemulsion and were coated with TiO2 by a precipitation technique. The synthesize process were done under fixed molar ratio of various constituents of microemulsion and molar ratio of water to oil. Results of X-ray diffraction spectroscopy (XRD) showed that the uncoated nanoparticles were consisted of magnetite as the major phase and no other detectable phases such as pure iron or hematite were found. Field emission scanning electron microscopy (FE-SEM) results showed that the synthesized nanoparticles small size and narrow particle size distribution. For TiO2 coating process the effect of TBOT concentration, water concentration,... 

    Factors Affecting the Efficiency of Ferrite Process for Removal of Heavy Metals (Case study of Chromium and Nickel)

    , M.Sc. Thesis Sharif University of Technology Abdolshahinejad, Sara (Author) ; Borgheei, Mahdi (Supervisor)
    Heavy metals, present in many industrial wastewaters, are considered as major pollutants of environment. Various methods to removal heavy metals effectively from effluents have been used in industry, yet more efficient and economical methods are required. Magnetic iron nanoparticles are known for their superior adsorption, ion exchange and electro-static forces characteristics.The aim of this study was to evaluate the efficiency of magnetic nanoparticles for removal of hexavalent chromium (VI) and Divalent nickel from wastewater and the parameters that influence the removal.The magnetite nanoparticles were prepared by co-precipitation method where produced Fe3O4 nanoparticle’s average size... 

    Effect of Coprecipitation and Hydrothermal Parameters on the Properties of Ferrofluids Based on Magnetite Nanoparticles as MRI Contrast Agent

    , Ph.D. Dissertation Sharif University of Technology Ahmadi, Reza (Author) ; Madaah Hosseini, Hamid Reza (Supervisor)
    Ferrofluids are special stable suspensions of magnetic nanoparticles dispersed in liquid phase. These materials have numerous biological applications such as drug delivery, magnetic hyperthermia and magnetic resonance imaging due to their special magnetic properties and fluidity. Particle size and magnetic properties of ferrofluids have an important role in these applications. In this work, magnetite-based ferrofluids have been synthesized via coprecipitation and hydrothermal methods. In the coprecipitation process, cysteine and dextran surfactants have been used as ferrofluid stabilizer and effect of synthesize temperature, time, pH and surfactant concentration have been investigated on... 

    Solid phase extraction of trace amounts of Pb(II) in opium, heroin, lipstick, plants and water samples using modified magnetite nanoparticles prior to its atomic absorption determination

    , Article Journal of the Iranian Chemical Society ; Volume 9, Issue 2 , 2012 , Pages 171-180 ; 1735207X (ISSN) Karimi, M. A ; Hatefi Mehrjardi, A ; Mohammadi, S. Z ; Mohadesi, A ; Mazloum Ardakani, M ; Hormozi Nezhad, M. R ; Kabir, A. A ; Sharif University of Technology
    A new, simple, fast and reliable solid-phase extraction method has been developed for separation/preconcentration of trace amounts of Pb(II) using dithizone/sodium dodecyl sulfate-immobilized on alumina-coated magnetite nanoparticles, and its determination by flame atomic absorption spectrometry (FAAS) and graphite furnace atomic absorption spectrometry (GFAAS) after eluting with 4.0 mol L -1 HNO 3. Optimal experimental conditions including pH, sample volume, eluent concentration and volume, and co-existing ions have been studied and established. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range and relative standard deviation of Pb(II)... 

    Comparison of different strategies for the assembly of gold colloids onto Fe3O4@SiO2 nanocomposite particles

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 49 , 2013 , Pages 30-38 ; 13869477 (ISSN) Mohammad Beigi, H ; Yaghmaei, S ; Roostaazad, R ; Arpanaei, A ; Sharif University of Technology
    Three strategies were employed for the assembly of gold nanoparticles on silica-coated magnetite particles (SCMPs). In strategy I, citrate-coated gold nanoparticles were attached on the surface of amine-SCMPs. In strategy II, amine-SCMPs were coated with carboxylated gold nanoparticles via amide bond formation. In strategy III, the thiol-SCMPs surface was coated with gold nanoparticles. Among the above examined strategies, coating amine-SCMPs with gold nanoparticles via strategy I resulted in a better coverage and stronger intensity of absorption bands. Furthermore, results obtained through strategy I showed that decreasing the pH of the solution from 7 to 3 leads to a further red-shift of... 

    Kinetics of magnetite nanoparticles formation in a one step low temperature hydrothermal process

    , Article Ceramics International ; Volume 39, Issue 5 , July , 2013 , Pages 4999-5005 ; 02728842 (ISSN) Ahmadi, R ; Masoudi, A ; Madaah Hosseini, H. R ; Gu, N ; Sharif University of Technology
    In the present study, a one step hydrothermal process was employed to synthesize magnetite nanoparticles using oleic acid as surfactant agent at 140 °C. Effects of reaction time and alkalinity were studied on particles size and morphology. By changing these parameters, some monodisperse spherical nanoparticles with mean particle size between 2.71 and 13.88 nm were synthesized and characterized via TEM, XRD, VSM, TGA and FT-IR techniques. Assuming the Avrami behavior of particles formation, a kinetics equation was proposed for the transformation rate at 140 °C. Using some simplifying assumptions, nucleation and growth rates were calculated for the hydrothermal formation of magnetite... 

    , M.Sc. Thesis Sharif University of Technology Azimi, Saloomeh (Author) ; Maddah Hosseini, Hamid Reza (Supervisor)
    A biocompatible ferrofluid have been prepared by co-precipitation of FeCl2.4H2O and FeCl3.6H2O under ultrasonic irradiation and with NaOH as alkaline agent. Also cystein was used as capping agent in the solution. Magnetic properties of the produced ferrofluid then determined by VSM test and magnetite nanoparticles were characterized by XRD and TEM techniques. Results indicate the presence of a biocompatible superparamagnetic ferrofluid including magnetite nanoparticles with particle size ranging under 15 nm. The effect of ultrasonic irradiation on presence of a sharp particle size distribution then denoted by comparing the condition with production without ultrasonic irradiation  

    Preparation of Metal Nanoparticles/Ionic Liquid Composites and Investigation of Their Catalytic Activity

    , M.Sc. Thesis Sharif University of Technology Gharegozloo, Nazanin (Author) ; Gholami, Mohammad Reza (Supervisor) ; Salari, Hadi (Co-Advisor)
    In this research Fe3O4 magnetic nanoparticles were prepared. To protect against oxidation, a shell of SiO2 was deposited on Fe3O4. Graphene oxide was prepared by the modified Hummer method and supported on the Fe3O4@SiO2 core-shell. Then, ionic liquid layer was impregnated on it. Afterward, PtAu nano alloy were synthesized on the surface of nanocomposite with the different molar ration including 100:0, 75:25, 50:50, 25:75 and 0:100. The as-prepared nanocomposite was characterized by SEM, XRD, and FT-IR analytical methods.For investigation of kinetically activity of catalysts, reduction of 4-nitrophenol with NaBH4 as reducer was used. The adsorption in different times was obtained by UV-vis... 

    A Facile, Two-step Synthesis and Characterization of Fe3O4-Lcysteine- Graphene Quantum Dots as a Multifunctional Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Alaghmand Fard, Amir Hossein (Author) ; Madah Hosseini, Hamid Reza (Supervisor)
    In this research, a facile, two-step synthesis was reported for 34-LCysteine- nanocomposites. The first step comprises the preparation of LCysteine functionalized magnetic nanoparticles (MNPs) core-shell structures via co-precipitation method. In the second step, graphene quantum dots (GQDs), which were synthesized by citric acid carbonization, added to the functionalized MNPs and finally refluxed at the appropriate time and temperature. LCysteine as a biocompatible, natural amino acid were used to link MNPs with GQDs. This nanocomposite was characterized by various techniques. XRD and FT-IR were used to investigate the formation of MNPs and LCysteine existence on the MNPs surface. XPS... 

    Preconcentration and determination of pantoprazole by solid-phase extraction coupled with spectrophotometry using iron oxide nanoparticles modified with cetyltrimethylammonium bromide

    , Article Nano Biomedicine and Engineering ; Volume 7, Issue 3 , 2015 , Pages 102-110 ; 21505578 (ISSN) Sayyahmanesh, M ; Naghian, E ; Sahebi, H ; Asgari, S ; Sharif University of Technology
    Open Access House of Science and Technology  2015
    Solid phase extraction coupled with spectrophotometric detection was applied to trace amounts of Pantoprazole (PP) drug using Cetyltrimethylammonium bromide coated-iron oxide magnetite nanoparticles CTAB@Fe3O4 MNPs. After characterization of the prepared nano-adsorbents, experimental parameters affecting the extraction efficiency of the developed method were optimized. The results obtained showed that this proposed approach is applicable in concentrations ranging from 0.1 to 1.5 μg/ml (R2 = 0.9958) indicating that follows Beer's-Lambert law. The limit of detection and the limit of quantification calculated to be 0.014 and 0.04 μg/ml, respectively. The repeatability of the proposed method was... 

    Covalent immobilization of cellulase using magnetic poly(ionic liquid) support: improvement of the enzyme activity and stability

    , Article Journal of Agricultural and Food Chemistry ; Volume 66, Issue 4 , 2018 , Pages 789-798 ; 00218561 (ISSN) Hosseini, H ; Hosseini, A ; Zohreh, N ; Yaghoubi, M ; Pourjavadi, A ; Sharif University of Technology
    American Chemical Society  2018
    A magnetic nanocomposite was prepared by entrapment of Fe3O4 nanoparticles into the cross-linked ionic liquid/epoxy type polymer. The resulting support was used for covalent immobilization of cellulase through the reaction with epoxy groups. The ionic surface of the support improved the adsorption of enzyme, and a large amount of enzyme (106.1 mg/g) was loaded onto the support surface. The effect of the presence of ionic monomer and covalent binding of enzyme was also investigated. The structure of support was characterized by various instruments such as FT-IR, TGA, VSM, XRD, TEM, SEM, and DLS. The activity and stability of immobilized cellulase were investigated in the prepared support. The... 

    RSM based engineering of the critical gelation temperature in magneto-thermally responsive nanocarriers

    , Article European Polymer Journal ; Volume 120 , 2019 ; 00143057 (ISSN) Khodaei, A ; Bagheri, R ; Madaah Hosseini, H. R ; Bagherzadeh, E ; Sharif University of Technology
    Elsevier Ltd  2019
    The multistep release of therapeutic agents in the theranostic particulate systems has remained as a challenge in smart drug delivery. In this study, superparamagnetic nanoparticles of Fe3O4 were coated with a blend of F127/F68 grades of pluronic in order to adjust the lower critical solution temperature (LCST) and consequently engineering of the release temperature. Pluronic as a biocompatible thermo-sensitive polymer is frequently used as a self-emulsifying drug delivery system. Magnetite nanoparticles with double layer coating of oleic acid and pluronic F127 have been reported as an on-demand smart carrier for hydrophobic drugs. LCST was examined using differential scanning calorimetry... 

    Synthesis, characterization and catalytic activity of supported vanadium Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation of alkenes and oxidation of sulfides

    , Article Journal of Organometallic Chemistry ; Volume 897 , 2019 , Pages 200-206 ; 0022328X (ISSN) Bagherzadeh, M ; Bahjati, M ; Mortazavi Manesh, A ; Sharif University of Technology
    Elsevier B.V  2019
    A new magnetically separable nanocatalyst was successfully synthesized by immobilizing of vanadyl acetylacetonate complex, [VO(acac)2], onto silica coated magnetite nanoparticles previously functionalized with 3-aminopropyltriethoxysilane (3-APTES) and reacted by 5-bromosalicylaldehyde to form Schiff base moiety. The obtained nanocatalyst was characterized by elemental analysis (CHN), FT-IR spectroscopy, Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and thermogravimetric analysis (TGA). Eventually, the resulting nanoparticles were used as catalyst for epoxidation of alkenes and... 

    Cancer cell enrichment on a centrifugal microfluidic platform using hydrodynamic and magnetophoretic techniques

    , Article Scientific Reports ; Volume 11, Issue 1 , 2021 ; 20452322 (ISSN) Shamloo, A ; Naghdloo, A ; Besanjideh, M ; Sharif University of Technology
    Nature Research  2021
    Isolation of rare cancer cells is one of the important and valuable stages of cancer research. Regarding the rarity of cancer cells in blood samples, it is important to invent an efficient separation device for cell enrichment. In this study, two centrifugal microfluidic devices were designed and fabricated for the isolation of rare cancer cells. The first design (passive plan) employs a contraction–expansion array (CEA) microchannel which is connected to a bifurcation region. This device is able to isolate the target cells through inertial effects and bifurcation law. The second design (hybrid plan) also utilizes a CEA microchannel, but instead of using the bifurcation region, it is... 

    The Study of Function of Lipase Biocatalyst Immobilized on Silica Nanoparticles Used for Biodiesel Production

    , M.Sc. Thesis Sharif University of Technology Kalantari, Mohammad (Author) ; Kazemini, Mohammad (Supervisor) ; Arpanaei, Ayyoob (Supervisor) ; Tabandeh, Fatemeh (Co-Advisor)
    Superparamagnetic core/shell nonporous (S1) and core/shell/shell mesoporous (S2 and S3) nanocomposite magnetite/silica particles with a magnetite cluster core of 130±30 nm, a nonporous silica shell of 90±10 nm thickness, and a mesoporous silica shell of 70±15 nm thickness were prepared thorough a simple method. Mesoporous particles were prepared with two BJH pore sizes (2.44 for S2 and 3.76 nm for S3 particles, respectively). The fabricated S1, S2 and S3 particles present high saturation magnetization values of 20, 13 and 17 emu/g, respectively. As a biological application, the lipase from Pseudomonas cepacia was successfully immobilized onto the amino-functionalized nanocomposite particles... 

    Experimental Study of Biological Synthesis, Stabilization and Delivery of the Recombinant Protein of Chondroitinase

    , Ph.D. Dissertation Sharif University of Technology Askaripour, Hossein (Author) ; Vossoughi, Manouchehr (Supervisor) ; Alemzadeh, Iran (Supervisor) ; Khajeh, Khosro (Supervisor)
    In this research, immobilization method was employed to increase the thermal stability of Chondroitinase ABC I (cABC I) enzyme. In first step, magnetite nanoparticle (Fe3O4) was selected as a support and cABC I enzyme was attached via the adsorption method. The results showed that pH=6.5, temperature 15 ˚C, enzyme-to-support mass ratio 0.75, and incubation time 4.5 hr were the appropriate conditions for immobilizing cABC I enzyme on Fe3O4 nanoparticle. It was also found that the optimum pH for free and immobilized enzymes was 7.6 and 8.0, respectively. The maximum activity of free enzyme was obtained at 25 ˚C, whereas the activity of immobilized enzyme was almost constant in the temperature... 

    Synthesis and Characterization of Dextran Based Magnetic Nanogels as a Gene Delivery Vector and Investigating its Gene Therapy Efficiency

    , M.Sc. Thesis Sharif University of Technology Azadpour, Behnam (Author) ; Madaah Hosseini, Hamid Reza (Supervisor) ; Arefian, Ehsan (Supervisor)
    The use of magnetic nanoparticles modified with proper surface agent and the ability of controlling by magnetic field, that can induce colloidal stability, is considered as a vector to transfer DNA plasmid, or pDNA in short, in the field of gene therapy. In thiss research, pH-responsive dextran-based magnetic nanogels (dextMNGs) were synthesized via inverse mini-emulsion method. Fourier transformation infrared spectroscopy (FTIR) showed that magnetite nanoparticles (MNPs) were successfully modified with arginine and had amine terminals. FTIR, also, proved that aldehyded dextran was crosslinked by arginine modified magnetite nanoparticles (RMNPs) via pH sensitive imine bonds. X-ray...