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1

Preparation of Nanoparticles of Barium Ferrite from Precipitation in Microemulsions  

Microsoft Academic Search

Magnetic nanoparticles of barium ferrite (BaFe12O19) have been synthesized using a microemulsion mediated process. The aqueous cores of water-in-oil microemulsions were used as constrained microreactors for the precipitation of precursor carbonate and hydroxide particles. These precursors were then calcined at 925°C for 12?h, during which time they were transformed to the hexagonal ferrite. The pH of reaction was varied between

B. J. Palla; D. O. Shah; P. Garcia-Casillas; J. Matutes-Aquino

1999-01-01

2

Preparation and characterization of cobalt ferrite nanoparticles coated with fucan and oleic acid  

NASA Astrophysics Data System (ADS)

Cobalt ferrite has attracted considerable attention in recent years due to its unique physical properties such as high Curie temperature, large magnetocrystalline anisotropy, moderate saturation magnetization, large magnetostrictive coefficient, excellent chemical stability and mechanical hardness. In this work we present the preparation, of fucan coated cobalt ferrite nanoparticles by a modified co-precipitation method and the study of their structural, microstructural and magnetic characteristics for their application as a solid support for enzymes immobilization and other biotechnology applications. Aqueous suspensions of magnetic particles were prepared by coprecipitation of Fe(III) and Co(II) in the presence of NaOH, acid oleic and fucan polymer. The X-ray diffraction indicates that the funtionalization does not degrade the core cobalt ferrite. The infrared (FTIR) bands, indicate the functional characteristics of the coating on the cobalt ferrite. Mössbauer spectra at room temperature indicate the presence of a broadened sextet plus a doublet which is typical of superparamagnetic relaxation. For the Co-ferrite uncoated and coated with fucan the doublets have areas of 36.1 % and 40.3 % respectively, indicating the presence of non-interacting particles and faster relaxation time. The Co-ferrite coated with oleic acid and oleic acid plus fucan have areas around 17.5 % and 17.1 % respectively which indicate a weak superparamagnetic relaxation due to a slow relaxation time. The magnetization measurements of the cobalt ferrite nanoparticles with and without coating confirm that they are superparamagnetic and this behavior is produced by the core nanoparticles rather than the coatings. The cobalt ferrite nanoparticles coated with oleic acid presented the highest magnetization than when coating with fucan.

Andrade, P. L.; Silva, V. A. J.; Maciel, J. C.; Santillan, M. M.; Moreno, N. O.; De Los Santos Valladares, L.; Bustamante, Angel; Pereira, S. M. B.; Silva, M. P. C.; Albino Aguiar, J.

2014-01-01

3

Preparation and characterization of ultra-stable biocompatible magnetic fluids using citrate-coated cobalt ferrite nanoparticles  

Microsoft Academic Search

Preparation and characterization of ultra-stable biocompatible cobalt ferrite-based magnetic fluids has been reported. Synthesized samples have core particle diameter in the range of 4.7 to 14.8 nm, as indicated by TEM. Chemical and crystalline data show that the prepared nanoparticles are cobalt ferrite with a slight deviation from the Fe:Co::2:1 stoichiometry. ATR-FTIR spectroscopy was used to investigate the citrate adsorption

P. C. Morais; R. L. Santos; A. C. M. Pimenta; R. B. Azevedo; E. C. D. Lima

2006-01-01

4

Preparation of cobalt ferrite nanoparticles via a novel solvothermal approach using divalent iron salt as precursors  

SciTech Connect

Graphical abstract: CoFe{sub 2}O{sub 4} nanoparticles are obtained via solvothermal approach using Fe{sup 2+} salt as iron resource. The magnetic properties can be modified by some additives. Display Omitted Highlights: ? CoFe{sub 2}O{sub 4} nanoparticles are synthesized by a facile one-step novel solvothermal method. ? The system is firstly performed in water–glycol mixture solvent with an ordinary air surrounding. ? The ferrous ions are used as iron source without adding oxidant. ? It is firstly found the low-coercivity CoFe{sub 2}O{sub 4} nanoparticles can be obtained with the help of some additives in the synthesis system. -- Abstract: Cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles are synthesized by a facile novel solvothermal method. The reactions are firstly performed in water–glycol system and Fe{sup 2+} salt is used as iron source without oxidant help. Some factors influenced the reactions, including temperature, reaction time, additives, are investigated. The samples are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), respectively. The magnetic properties of some samples are detected by vibrating sample magnetometry techniques (VSM). It is firstly found that the magnetism of cobalt ferrites nanomaterials can be modified by some additives. The coercivity of CoFe{sub 2}O{sub 4} nanoparticles evidently decreases from 600 to 50 Oe in the presence of PEG-4000 in the system.

Ma, Jie, E-mail: majie0203ch@hotmail.com [College of Science, University of Shanghai for Science and Technology (China) [College of Science, University of Shanghai for Science and Technology (China); Green Bio- and Eco-Chem. Eng. Lab, University of Shanghai for Science and Technology (China); Zhao, Jiantao; Li, Wenlie [College of Science, University of Shanghai for Science and Technology (China)] [College of Science, University of Shanghai for Science and Technology (China); Zhang, Shuping [College of Science, University of Shanghai for Science and Technology (China) [College of Science, University of Shanghai for Science and Technology (China); Green Bio- and Eco-Chem. Eng. Lab, University of Shanghai for Science and Technology (China); Tian, Zhenran; Basov, Sergey [College of Science, University of Shanghai for Science and Technology (China)] [College of Science, University of Shanghai for Science and Technology (China)

2013-02-15

5

Highly aluminium doped barium and strontium ferrite nanoparticles prepared by citrate auto-combustion synthesis  

SciTech Connect

Aluminium doped barium and strontium hexaferrite nanoparticles BaAl {sub x}Fe{sub (12-x)}O{sub 19} and SrAl {sub x}Fe{sub (12-x)}O{sub 19} were synthesised via a sol-gel route using citric acid to complex the ions followed by an auto-combustion reaction. This method shows promise for the synthesis of complex ferrite powders with small particle size. It was found that around half of the iron could be substituted for aluminium in the barium ferrite with structure retention, whereas strontium aluminium ferrites could be produced with any aluminium content including total substitution of the iron. All synthesised materials consisted of particles smaller than 1 {mu}m, which is the size of a single magnetic domain, and various doping levels were achieved with the final elemental composition being within the bounds of experimental error. The materials show structural and morphological changes as they move from iron to aluminium ferrites. Such materials may be promising for imaging applications.

Shirtcliffe, Neil J. [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom)]. E-mail: neil.shirtcliffe@ntu.ac.uk; Thompson, Simon [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom); O'Keefe, Eoin S. [QinetiQ, Farnborough, Hampshire (United Kingdom); Appleton, Steve [QinetiQ, Farnborough, Hampshire (United Kingdom); Perry, Carole C. [Nottingham Trent University, Clifton Lane, Clifton, Nottingham NG11 8NS (United Kingdom)]. E-mail: carole.perry@ntu.ac.uk

2007-02-15

6

Magnetocaloric effect in Ni-Zn ferrite nanoparticles prepared by using solution combustion  

NASA Astrophysics Data System (ADS)

Ni x Zn1- x Fe2O4 ( x = 0.2 and 0.3) ferrite nanoparticles with sizes ranging from 65 to 70 nm were synthesized employing the solution combustion route. The magnetocaloric behavior was investigated within the 50 K ? T ? 400 K range of temperatures ( T). The entropy change (? S) and the adiabatic temperature change (? T) were derived from magnetization ( M) and specific heat ( C P ) measurements. Both compositions exhibited broad peaks for the isothermal entropy change. The magnetic field ( H)-dependent ? T was analyzed within the mean-field approximation scheme, and the observed magnetocaloric properties of the nanoparticle samples were compared with those of a bulk sample. Our study suggests that the magnetocaloric properties of magnetic oxides strongly depend on the particle size; thus, particle size should be considered as a key tuning parameter in the optimization of magnetic refrigeration.

Lee, K. D.; Kambale, R. C.; Hur, N.

2014-12-01

7

Preparation of bismuth ferrite nanoparticles and their photocatalytic activity for MO degradation  

Microsoft Academic Search

A modified polyacrylamide gel method was used to fabricate Bi2Fe4O9 nanoparticles. Thermogravimetric (TG) analysis, differential scanning calorimetry (DSC) analysis, fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used in combination to investigate the thermal decomposition process of xerogels and the formation of Bi2Fe4O9 phase. It is demonstrated that high-phase-purity Bi2Fe4O9 nanoparticles can be prepared at a calcining temperature

Man Zhang; Hua Yang; Tao Xian; Zhiqiang Wei; Wangjun Feng

2011-01-01

8

Synthesis and magnetic properties of cobalt ferrite (CoFe 2O 4) nanoparticles prepared by wet chemical route  

Microsoft Academic Search

Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single-phase cobalt ferrite nanoparticles in the range 15–48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature

K. Maaz; Arif Mumtaz; S. K. Hasanain; Abdullah Ceylan

2007-01-01

9

Structural and magnetic properties of magnesium ferrite nanoparticles prepared via EDTA-based sol-gel reaction  

NASA Astrophysics Data System (ADS)

Magnesium ferrite (MgFe2O4) nanoparticles have been prepared, for the first time, by ethylene diamine tetraacetic acid (EDTA)-based sol-gel combustion method. The prepared ferrite system is calcined at 400, 500 and 600 °C. Thermo-gravimetric and differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometry (VSM) were applied for elucidating the structural and magnetic properties of the prepared system. XRD patterns revealed that the prepared system have two spinel MgFe2O4 structures, namely cubic and tetragonal phases that are dependent on calcination temperature (Tc). The crystallite sizes varied from 8.933 to 41.583 nm, and from 1.379 to 292.565 nm for the cubic and tetragonal phases respectively depending on Tc. The deduced lattice parameters for the cubic and (tetragonal) systems are a=8.368, 8.365 and 8.377 and (a=7.011, 5.922, 5.908 and c=6.622, 8.456, 8.364) Å at Tc=400, 500 and 600 °C respectively. While the cation distribution of the cubic phase is found to be mixed spinel and Tc-dependent, it is an inverse spinel in the tetragonal phase where the Fe3+ ions occupy both the tetrahedral A- and octahedral B-sites in almost equal amount; the Mg2+ ions are found to occupy only the B-sites. The HRTEM and selected-area electron diffraction (SAED) revealed the detailed morphology of the nanoparticles, and confirmed their crystalline spinel structure. VSM indicated the existence of an appreciable fraction of superparamagnetic particles at room temperature, with pure superparamagnetic behavior observed for samples calcined at 400 °C. Besides, the magnetic properties are found to change by thermal treatment as a result of the varied phase concentration, cation distribution and lattice parameters. Thus, the new synthesis route used in this study by applying EDTA as an organic precursor for preparing MgFe2O4 nanoparticles at rather low temperatures proved to be efficient in obtaining nanoparticles with favorable structural and magnetic properties. Such properties would qualify them for several potential applications including e.g. in hyperthermia treatment, as contrast agents in magnetic resonance imaging (MRI), and in ferroelastomers technology.

Hussein, Shaban I.; Elkady, Ashraf S.; Rashad, M. M.; Mostafa, A. G.; Megahid, R. M.

2015-04-01

10

Oleate Coated Magnetic Cores Based on Magnetite, Zn Ferrite and Co Ferrite Nanoparticles - Preparation, Physical Characterization and Biological Impact on Helianthus Annuus Photosynthesis  

SciTech Connect

Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic nanoparticle levels of 10{sup -14}-10{sup -15}/cm{sup 3}) on sunflower seedlings was studied considering the changes in the photosynthesis pigment levels. Similar responses were obtained for magnetite and cobalt ferrite nanoparticle treatment consisting in the apparent inhibition of chlorophyll biosynthesis while for zinc ferrite nanoparticles some concentrations seemed to have stimulatory effects on the chlorophylls as well as on the carotene levels. But the chlorophyll ratio was diminished in the case of all three types of magnetic nanoparticles meaning their slight negative effect on the light harvesting complex II (LHC II) from the chloroplast membranes and consequently on the photosynthesis efficiency.

Ursache-Oprisan, Manuela; Foca-nici, Ecaterina; Cirlescu, Aurelian; Caltun, Ovidiu; Creanga, Dorina [Al. I. Cuza' University, Faculty of Physics, 11A Blvd.Copou, 700506, Iasi (Romania)

2010-12-02

11

Oleate Coated Magnetic Cores Based on Magnetite, Zn Ferrite and Co Ferrite Nanoparticles—Preparation, Physical Characterization and Biological Impact on Helianthus Annuus Photosynthesis  

NASA Astrophysics Data System (ADS)

Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic nanoparticle levels of 10-14-10-15/cm3) on sunflower seedlings was studied considering the changes in the photosynthesis pigment levels. Similar responses were obtained for magnetite and cobalt ferrite nanoparticle treatment consisting in the apparent inhibition of chlorophyll biosynthesis while for zinc ferrite nanoparticles some concentrations seemed to have stimulatory effects on the chlorophylls as well as on the carotene levels. But the chlorophyll ratio was diminished in the case of all three types of magnetic nanoparticles meaning their slight negative effect on the light harvesting complex II (LHC II) from the chloroplast membranes and consequently on the photosynthesis efficiency.

Ursache-Oprisan, Manuela; Foca-nici, Ecaterina; Cirlescu, Aurelian; Caltun, Ovidiu; Creanga, Dorina

2010-12-01

12

Photocatalytic activities of multiferroic bismuth ferrite nanoparticles prepared by glycol-based sol–gel process  

Microsoft Academic Search

The uniform multiferroic BiFeO3 nanoparticles with fairly narrow particle size distribution have been successfully synthesized by a simple glycol-based sol–gel\\u000a route at relatively low temperature. The thus-prepared powders were characterized by X-ray diffractometry (XRD), thermogravimetric\\u000a and differential thermal analysis (DTA\\/TG), and transmission electron microscopy (TEM). Rapid sintering and subsequently quenching\\u000a to room temperature are the two vital important factors for

X. WangY; Y. Lin; Z. C. Zhang; J. Y. Bian

13

Preparation and magnetic properties of hexagonal barium ferrite films using BaM nanoparticles  

Microsoft Academic Search

Barium ferrite (BaFe12O19—BaM) thick films have been synthesized using a spinning coating sol–gel process. The coating sol was formed from BaM powders dispersed in the BaM raw sol. XRD, SEM, EDX, vibrating sample magnetometer (VSM), and ac susceptometer, were employed to evaluate the structure, composition and magnetic properties of BaM thick films. The results indicated that a uniform and crack-free

Ali Ghasemi; Reza Shams Alam; Akimitsu Morisako

2008-01-01

14

Preparation of single-crystal copper ferrite nanorods and nanodisks  

SciTech Connect

This article, for the first time, reports the preparation of single-crystal copper ferrite nanorods and nanodisks. Using amorphous copper ferrite nanoparticles synthesized by reverse micelle as reaction precursor, single-crystal copper ferrite nanorods were synthesized via hydrothermal method in the presence of surfactant polyethylene glycol (PEG), however, copper ferrite nanodisks were prepared through the same procedures except the surfactant PEG. The resulting nanomaterials have been characterized by powder X-ray diffraction (XRD), selected electron area diffraction (SEAD), and transmission electron microscopy (TEM). The bulk composition of the samples was determined by means of X-ray photoelectron spectroscopy (XPS)

Du Jimin [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China); Liu Zhimin [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China)]. E-mail: liuzm@iccas.ac.cn; Wu Weize [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China); Li Zhonghao [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China); Han Buxing [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China)]. E-mail: hanbx@iccas.ac.cn; Huang Ying [Center for Molecular Sciences, CAS Key Laboratory of Colloid, Interfacial and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 Beiyijie, Zhongguancun, Beijing 100080 (China)

2005-06-15

15

Ferrite Nanoparticles in Pharmacological Modulation of Angiogenesis  

NASA Astrophysics Data System (ADS)

Nanoparticles are being explored in the targeted drug delivery of pharmacological agents : angiogenesis being one such novel application which involves formation of new blood vessels or branching of existing ones. The present study involves the use of ferrite nanoparticles for precise therapeutic modulation of angiogenesis. The ferrite nanoparticles synthesized by co-precipitation of ferrous and ferric salts by a suitable base, were found to be 10-20 nm from X-ray diffraction and TEM measurements. The magnetization measurements showed superparamagnetic behavior of the uncoated nanoparticles. These ferrite nanoparticles were found to be bio-compatible with lymphocytes and neural cell lines from the biochemical assays. The chick chorioallantoic membrane(CAM) from the shell of fertile white Leghorn eggs was chosen as a model to study angiogenic activity. An enhancement in the angiogenic activity in the CAM due to addition of uncoated ferrite nanoparticles was observed.

Deshmukh, Aparna; Radha, S.; Khan, Y.; Tilak, Priya

2011-07-01

16

Preparation, characterization, in vivo and in vitro studies of arsenic trioxide Mg-Fe ferrite magnetic nanoparticles  

Microsoft Academic Search

Aim:MgFe2O4 magnetic nanoparticle composed of As2O3 (As2O3-MNPs) were prepared and their in vitro and in vivo characteristics were studied.Methods:The solvent-displacement method was applied for preparation of the nanoparticle using Poly-D,L-lactic-co-glycolic acid(PLGA). The characteristics studies of the products included magnetic response, morphology (transmission electron microscopy and scanning electron microscopy), entrapment efficiency, drug loading, particle sizes, zeta potential, in vitro drug release

Guo-fu Yang; Xiang-hui Li; Zhe Zhao; Wen-bo Wang; Wen-bo Wang

2009-01-01

17

Study of DNA interaction with cobalt ferrite nanoparticles.  

PubMed

Interaction of cobalt ferrite nanopowder and nucleic acid was investigated. Superparamagnetic cobalt ferrite nanoparticles (6-12 nm) were prepared by mechanochemical synthesis. Structure of the nanopowder was characterized using X-ray diffraction. It was shown that cobalt ferrite nanoparticles were associated with ssDNA and dsDNA in Tris-buffer resulting in bionanocomposite formation with mass weight relation nanoparticles: DNA 1:(0.083 +/- 0.003) and 1:(0.075 +/- 0.003) respectively. The mechanism of interaction between a DNA and cobalt ferrite nanoparticles was considered basing on the whole set of obtained data: FTIR-spectroscopy, analyzing desorption of DNA from the surface of the particles while changing the chemical content of the medium, and on the modeling interaction of specific biomolecule fragments with surface of a inorganic material. It was supposed that the linkage was based on coordination interaction of the phosphate groups and oxygen atoms heterocyclic bases of DNA with metal ions on the particle surface. These data can be used to design specific magnetic DNA-nanoparticles hybrid structures. PMID:21449452

Pershina, A G; Sazonov, A E; Novikov, D V; Knyazev, A S; Izaak, T I; Itin, V I; Naiden, E P; Magaeva, A A; Terechova, O G

2011-03-01

18

Strong and moldable cellulose magnets with high ferrite nanoparticle content.  

PubMed

A major limitation in the development of highly functional hybrid nanocomposites is brittleness and low tensile strength at high inorganic nanoparticle content. Herein, cellulose nanofibers were extracted from wood and individually decorated with cobalt-ferrite nanoparticles and then for the first time molded at low temperature (<120 °C) into magnetic nanocomposites with up to 93 wt % inorganic content. The material structure was characterized by TEM and FE-SEM and mechanically tested as compression molded samples. The obtained porous magnetic sheets were further impregnated with a thermosetting epoxy resin, which improved the load-bearing functions of ferrite and cellulose material. A nanocomposite with 70 wt % ferrite, 20 wt % cellulose nanofibers, and 10 wt % epoxy showed a modulus of 12.6 GPa, a tensile strength of 97 MPa, and a strain at failure of ca. 4%. Magnetic characterization was performed in a vibrating sample magnetometer, which showed that the coercivity was unaffected and that the saturation magnetization was in proportion with the ferrite content. The used ferrite, CoFe2O4, is a magnetically hard material, demonstrated by that the composite material behaved as a traditional permanent magnet. The presented processing route is easily adaptable to prepare millimeter-thick and moldable magnetic objects. This suggests that the processing method has the potential to be scaled-up for industrial use for the preparation of a new subcategory of magnetic, low-cost, and moldable objects based on cellulose nanofibers. PMID:25331121

Galland, Sylvain; Andersson, Richard L; Ström, Valter; Olsson, Richard T; Berglund, Lars A

2014-11-26

19

Preparation of ferrite-coated MFM cantilevers  

NASA Astrophysics Data System (ADS)

Ferrite-coated magnetic force microscopy (MFM) cantilevers were prepared for the use with a high-frequency MFM (HF-MFM) setup. The ferrite coatings were fabricated by means of radio frequency (RF) magnetron sputtering directly on the Si surface. Two types of ferrites were employed in this study: NiZnFe 2O 4 spinel and Co 2Z-type hexaferrite (Ba 3Co 2Fe 24O 41, BCFO). The typical thickness of the coatings was 50 nm. For comparison, ferrite samples on (1 0 0) and (1 1 1)-oriented Si substrates (analogous to the surfaces of the cantilevers) were prepared. Successful HF-MFM imaging was performed with both types of cantilevers using harddisk writer poles as samples. The HF-MFM images obtained by ferrite-coated cantilevers evidently reveal more details of the magnetic field distribution of the writer poles up to the GHz range than conventional CoCr-coated MFM cantilevers.

Koblischka, M. R.; Kirsch, M.; Wei, J.; Sulzbach, T.; Hartmann, U.

2007-09-01

20

Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel ferrite nanoparticles were prepared by a modified sol-gel technique employing coconut oil, and then annealed at different temperatures in 400-1200 °C range. This route of preparation has revealed to be one efficient and cheap technique to obtain high quality nickel ferrite nanosized powder. Sample particles sizes obtained with XRD data and Scherrer's formula lie in 13 nm to 138 nm, with increased size with annealing temperature. Hysteresis loops have been obtained at room temperature with an inductive method. Magnetic field induced microwave absorption in nanoscale ferrites is a recent an active area of research, in order to characterize and explore potential novel applications. In the present work microwave magnetoabsorption data of the annealed nickel ferrite nanoparticles are presented. These data have been obtained with a system based on a network analyzer that operates in the frequency range 0 - 8.5 GHz. At fields up to 400 mT we can observe a peak according to ferromagnetic resonance theory. Sample annealed at higher temperature exhibits different absorption, coercivity and saturation magnetization figures, revealing its multidomain character.

Hernández-Gómez, P.; Muñoz, J. M.; Valente, M. A.; Torres, C.; de Francisco, C.

2013-01-01

21

Ferrite nanoparticles for future heart diagnostics  

NASA Astrophysics Data System (ADS)

Normally, CoFe2O4 has been known as ferromagnetic ferrite with a quite large magnetic moment. However, since we aim to inject the particles into the human body, we are also interested in ZnFe2O4 because in the human body, Fe and Zn exist, so that adding ZnFe2O4 is safer. In both cases, the nanoparticles are coated by silica in order to get rid of toxicity. Our main purpose is to test whether these nanoparticles affect the contractile function of heart cells. Our results on rat's heart cells have shown that both Zn and Co ferrites improved the contractility of heart cells. Notably, although both nanoparticles increased contraction and delayed relaxation, Co ferrites induced a greater contraction but with a slower relaxation. We can theoretically argue that the magnetization effects of the quantum dots have a considerable effect on the pulsating properties of the heart cells. Through this effect, the locally applied magnetic field is able to induce as well as turn on/off various regular beating patterns, thus, resetting the heart beatings.

Hong, Nguyen Hoa; Raghavender, A. T.; Ciftja, O.; Phan, M.-H.; Stojak, K.; Srikanth, H.; Zhang, Yin Hua

2013-08-01

22

Low-temperature calorimetric properties of zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Calorimetric measurements between 1 and 40 K by a thermal relaxation technique have been made on zinc ferrite nanoparticles prepared from an aerogel process. The expected ?-type heat-capacity peak near 10 K, which corresponds to a long-range antiferromagnetic transition in the bulk form of this material, is greatly suppressed. Broad peaks begin to prevail after the sample is annealed at 500 or 800 °C, but ball milling of the nanoparticles leads to almost complete disappearance of the low-temperature ordering. In all cases, calorimetrically based magnetic entropy at 40 K accounts for only a fraction of 2R ln(2S+1) with S=5/2 for Fe3+. These results are corroborated by magnetic data, which also indicate magnetic ordering at high temperatures. Such observations can be understood by considering the relative distribution of Fe3+ between two nonequivalent (A and B) sites in the spinel-type lattice. In particular, the as-prepared fine particles show large Fe3+ occupancy of the A sites, whereas these ions prefer the B sites in bulk zinc ferrite. Meanwhile, the lattice heat capacity is enhanced, yielding effective Debye temperatures of 225, 285, 345, and 360 K for the as-prepared, 500 °C-annealed, 800 °C-annealed, and ball milled sample, respectively, in contrast to 425 K for the bulk material.

Ho, J. C.; Hamdeh, H. H.; Chen, Y. Y.; Lin, S. H.; Yao, Y. D.; Willey, R. J.; Oliver, S. A.

1995-10-01

23

Cobalt ferrite nanoparticles: The control of the particle size and surface state and their effects on magnetic properties  

Microsoft Academic Search

In order to improve the efficacy of magnetic fluid hyperthermia (MFH) mediators, we synthesised cobalt ferrite nanoparticles with different sizes (between 5 and 7nm) via successive polyol synthesis. The static and dynamic magnetic properties of the prepared particles, dispersed in a solid matrix, were investigated in order to evaluate the possibility of applying cobalt ferrite as magnetic susceptors in MFH.

Giovanni Baldi; Daniele Bonacchi; Claudia Innocenti; Giada Lorenzi; Claudio Sangregorio

2007-01-01

24

Preparation of acicular NiZn-ferrite powders  

Microsoft Academic Search

Acicular NiZn-ferrite powder particles have been prepared from goethite-derived acicular Fe2O3 and spherical constituent oxides in the presence of molten chloride or sulphate. The morphology of NiZn-ferrite particles has been studied with reference to the effect of chemical species of molten salts, ferrite composition and particle size of constituent divalent oxides. Hence the best preparation conditions for acicular NiZn-ferrite powder

Yoshihiro Hayashi; Toshio Kimura; Takashi Yamaguchi

1986-01-01

25

Spindly cobalt ferrite nanocrystals: preparation, characterization and magnetic properties  

Microsoft Academic Search

In this paper we describe the preparation of homogeneously needle-shaped cobalt ferrite (CoFe2O4) nanocrystals on a large scale through the smooth decomposition of urea and the resulting co-precipitation of Co2+ and Fe3+ in oleic acid micelles. Furthermore, we found that other ferrite nanocrystals with a needle-like shape, such as zinc ferrite (ZnFe2O4) and nickel ferrite (NiFe2O4), can be prepared by

Xuebo Cao; Li Gu

2005-01-01

26

Fabrication of Mn-ferrite nanoparticles from MnO colloids.  

PubMed

The reaction mechanism for conversion of MnO nanoparticles to Mn-ferrite nanoparticles was studied, which involved sequential consumption of MnO and the growth of ferrite. The method could be applied to other ferrite nanoparticles including cobalt ferrite. PMID:19885477

Han, Anna; Choi, Donghyuk; Kim, Taehei; Lee, Jei Hee; Kim, Jai Keun; Yoon, Mi Jin; Choi, Kyeong Sook; Kim, Sang-Wook

2009-11-28

27

Optimizing hysteretic power loss of magnetic ferrite nanoparticles  

E-print Network

This thesis seeks to correlate hysteretic power loss of tertiary ferrite nanoparticles in alternating magnetic fields to trends predicted by physical models. By employing integration of hysteresis loops simulated from ...

Chen, Ritchie

2013-01-01

28

Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications.  

PubMed

Transition metals of copper, zinc, chromium and nickel were substituted into cobalt ferrite nanoparticles via a sol-gel route using citric acid as a chelating agent. The microstructure and elemental composition were characterized using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. Phase analysis of transition metal-substituted cobalt ferrite nanoparticles was performed via X-ray diffraction. Surface wettability was measured using the water contact angle technique. The surface roughness of all nanoparticles was measured using profilometry. Moreover, thermogravimetric analysis and differential scanning calorimetry were performed to determine the temperature at which the decomposition and oxidation of the chelating agents took place. Results indicated that the substitution of transition metals influences strongly the microstructure, crystal structure and antibacterial property of the cobalt ferrite nanoparticles. PMID:23137676

Sanpo, Noppakun; Berndt, Christopher C; Wen, Cuie; Wang, James

2013-03-01

29

Dielectric properties of cobalt ferrite nanoparticles in ultrathin nanocomposite films.  

PubMed

Multilayered nanocomposite films (thickness 50-90 nm) of cobalt ferrite nanoparticles (np-CoFe2O4, 18 nm) were deposited on top of interdigitated microelectrodes by the layer-by-layer technique in order to study their dielectric properties. For that purpose, two different types of nanocomposite films were prepared by assembling np-CoFe2O4 either with poly(3,4-ethylenedioxy thiophene):poly(styrene sulfonic acid) or with polyaniline and sulfonated lignin. Despite the different film architectures, the morphology of both was dominated by densely-packed layers of nanoparticles surrounded by polyelectrolytes. The dominant effect of np-CoFe2O4 was also observed after impedance spectroscopy measurements, which revealed that dielectric behavior of the nanocomposites was largely influenced by the charge transport across nanoparticle-polyelectrolyte interfaces. For example, nanocomposites containing np-CoFe2O4 exhibited a single low-frequency relaxation process, with time constants exceeding 15 ms. At 1 kHz, the dielectric constant and the dissipation factor (tan ?) of these nanocomposites were 15 and 0.15, respectively. These values are substantially inferior to those reported for pressed pellets made exclusively of similar nanoparticles. Impedance data were further fitted with equivalent circuit models from which individual contributions of particle's bulk and interfaces to the charge transport within the nanocomposites could be evaluated. The present study evidences that such nanocomposites display a dielectric behavior dissimilar from that exhibited by their individual counterparts much likely due to enlarged nanoparticle-polyelectrolyte interfaces. PMID:24145704

Alcantara, Gustavo B; Paterno, Leonardo G; Fonseca, Fernando J; Pereira-da-Silva, Marcelo A; Morais, Paulo C; Soler, Maria A G

2013-12-01

30

Preparation of high-permeability NiCuZn ferrite.  

PubMed

Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature of NiZn ferrite from 1200 degrees C to 930 degrees C. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 degrees C is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 degrees C because the microstructure of the NiZn ferrite sintered at 930 degrees C is more uniform and compact than that of the NiZn ferrite sintered at 1200 degrees C. The high permeability of 1700 and relative loss coefficient tandelta/mu(i) of 9.0x10(-6) at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite. PMID:15909348

Hu, Jun; Yan, Mi

2005-06-01

31

Preparation of high-permeability NiCuZn ferrite*  

PubMed Central

Appropriate addition of CuO/V2O5 and the reduction of the granularity of the raw materials particle decrease the sintering temperature of NiZn ferrite from 1200 °C to 930 °C. Furthermore, the magnetic properties of the NiZn ferrite prepared at low temperature of 930 °C is superior to that of the NiZn ferrite prepared by sintering at high temperature of 1200 °C because the microstructure of the NiZn ferrite sintered at 930 °C is more uniform and compact than that of the NiZn ferrite sintered at 1200 °C. The high permeability of 1700 and relative loss coefficient tan?/?i of 9.0×10?6 at 100 kHz was achieved in the (Ni0.17Zn0.63Cu0.20)Fe1.915O4 ferrite. PMID:15909348

Hu, Jun; Yan, Mi

2005-01-01

32

The role of cobalt ferrite magnetic nanoparticles in medical science.  

PubMed

The nanotechnology industry is rapidly growing and promises that the substantial changes that will have significant economic and scientific impacts be applicable to a wide range of areas, such as aerospace engineering, nano-electronics, environmental remediation and medical healthcare. In this area, cobalt ferrite nanoparticles have been regarded as one of the competitive candidates because of their suitable physical, chemical and magnetic properties like the high anisotropy constant, high coercivity and high Curie temperature, moderate saturation magnetization and ease of synthesis. This paper introduces the magnetic properties, synthesis methods and some medical applications, including the hyperthermia, magnetic resonance imaging (MRI), magnetic separation and drug delivery of cobalt ferrite nanoparticles. PMID:25428034

Amiri, S; Shokrollahi, H

2013-01-01

33

Domain size correlated magnetic properties and electrical impedance of size dependent nickel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

We report here the investigations on the size dependent variation of magnetic properties of nickel ferrite nanoparticles. Nickel ferrite nanoparticles of different sizes (14 to 22 nm) were prepared by the sol-gel route at different annealing temperatures. They are characterized by TGA-DTA, XRD, SEM, TEM and Raman spectroscopy techniques for the confirmation of the temperature of phase formation, thermal stability, crystallinity, morphology and structural status of the nickel ferrite nanoparticles. The magnetization studies revealed that the saturation magnetization (Ms), retentivity (Mr) increase, while coercivity (Hc) and anisotropy (Keff) decrease as the particle size increases. The observed value of Ms is found to be relatively higher for a particle size of 22 nm. In addition, we have estimated the magnetic domain size using magnetic data and correlated to the average particle size. The calculated magnetic domain size is closely matching with the particle size estimated from XRD. Impedance spectroscopy was employed to study the samples in an equivalent circuit to understand their transport phenomena. It shows that nickel ferrite nanoparticles exhibit a non-Debye behavior with increasing particle size due to the influence of increasing disorders, surface effects, grain size and grain boundaries, etc.

Kamble, Ramesh B.; Varade, Vaibhav; Ramesh, K. P.; Prasad, V.

2015-01-01

34

Nanosized bismuth ferrite powder prepared through sonochemical and microemulsion techniques  

Microsoft Academic Search

Two processing routes, namely sonochemical and microemulsion have been exploited to prepare bismuth ferrite powders. Phase pure nanosized BiFeO3 powders are prepared by sonochemical and microemulsion techniques in the temperature range of 400 °C and at 500 °C which is much lower than that of the conventional preparation methods. The XRD obtained from both cases was likely to be pure bismuth ferrite.

Nandini Das; Ranabrata Majumdar; A. Sen; H. S. Maiti

2007-01-01

35

Influence of lanthanum on the optomagnetic properties of zinc ferrite prepared by combustion method  

NASA Astrophysics Data System (ADS)

Pure and lanthanum doped zinc ferrite nanoparticles were synthesized by a combustion method using glycine as fuel. The mechanism of formation of these nanoferrites is discussed briefly. The prepared nanoparticles characterized using powder X-ray diffraction analysis (XRD) revealed the formation of cubic spinel phase with high crystallinity. Average crystallite size, X-ray density and bulk density were found to decrease with an increase in La3+ concentration. The chemical elements and states on the surface of these ferrites were determined using X-ray photoelectron spectroscopy (XPS). The detailed core level spectra of the photoelectron peaks of Zn 2p, Fe 2p, La 3d and O 1s were analyzed. The magnetic behavior of these nanoparticles was studied using a vibrating sample magnetometer (VSM) and corresponding changes in the saturation magnetization (Ms), coercivity (Hc) and remanent magnetization (Mr) were analyzed. The optical behavior of these ferrite nanoparticles was characterized by UV-Diffuse reflectance studies (UV-DRS). From the UV-DRS studies, the optical band gap was found to be in the range of 1.87-1.97 eV. The combustion method significantly produces large amount of products within a short time. Therefore, this method is potentially suitable for manufacturing industries for preparing the magnetic nanoparticles.

Tholkappiyan, R.; Vishista, K.

2014-09-01

36

Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles  

Microsoft Academic Search

Hydrothermal microwave method (HTMW) was used to synthesize crystalline bismuth ferrite (BiFeO3) nanoparticles (BFO) in the temperature of 180°C with times ranging from 5min to 1h. BFO nanoparticles were characterized by means of X-ray analyses, FT-IR, Raman spectroscopy, TG-DTA and FE-SEM. X-ray diffraction results indicated that longer soaking time was benefit to refraining the formation of any impurity phases and

G. Biasotto; A. Z. Simões; C. R. Foschini; M. A. Zaghete; J. A. Varela; E. Longo

2011-01-01

37

Comparative Cytogenetic Study on the Toxicity of Magnetite and Zinc Ferrite Nanoparticles in Sunflower Root Cells  

NASA Astrophysics Data System (ADS)

In this experimental study the authors present their results regarding the cellular division rate and the percentage of chromosomal aberrations in the root meristematic cells of Helianthus annuus cultivated in the presence of different volume fractions of magnetic nanoparticle suspensions, ranging between 20 and 100 microl/l. The aqueous magnetic colloids were prepared from chemically co-precipitated ferrites coated in sodium oleate. Tissue samples from the root meristeme of 2-3 day old germinated seeds were taken to prepare microscope slides following Squash method combined with Fuelgen techniques. Microscope investigation (cytogenetic tests) has resulted in the evaluation of mitotic index and chromosomal aberration index that appeared diminished and respectively increased following the addition of magnetic nanoparticles in the culture medium of the young seedlings. Zinc ferrite toxic influence appeared to be higher than that of magnetite, according to both cytogenetic parameters.

Foca-nici, Ecaterina; Capraru, Gabriela; Creanga, Dorina

2010-12-01

38

Magnetic, electric and thermal properties of cobalt ferrite nanoparticles , N. Mlikia  

E-print Network

1 Magnetic, electric and thermal properties of cobalt ferrite nanoparticles L.Ajroudia , N. Mlikia]. The elaboration route developed led to chemically homogeneous spinel cobalt ferrites, with mean size ranging from. The sensing properties of cobalt ferrite nanoparticles were investigated, and different resistance variations

Paris-Sud XI, Université de

39

Synthesis and microstructure of cobalt ferrite nanoparticles L.Ajroudi1,2  

E-print Network

1 Synthesis and microstructure of cobalt ferrite nanoparticles L.Ajroudi1,2 , S.Villain1 , V Tunis, Tunisia Abstract Cobalt ferrites (CoxFe3-xO4) nanoparticles with various compositions were synthesized by a new non-aqueous synthesis method. The cobalt ferrites were characterized by X

Paris-Sud XI, Université de

40

Synthesis and charcterization of Nanocrystalline NiCuZn Ferrite prepared by Sol-gel auto combution method  

NASA Astrophysics Data System (ADS)

Promising future applications of ferrite nanoparticles in medicine, making many devices like permanent magnets, memory storage devices etc. Ferrite nanoparticles have been the emerging focus of the recent scientific research. Therefore nanostructured powders of ferrites having chemical compositions [Ni0.8-xCu0.2Znxfe2O4], where x=0.3, 0.5, synthesised through nitrate citrate by sol-gel autocombustion method from stoichiometric mixture of their respective metal nitrate. The prepared powders were sintered at 400 0C and 600 0C for 4 hours. The structural, morphology, ferrite formation of powder were determined by X-ray powder diffractometry (XRD), Scanning Electron Microscope (SEM) photograph of the samples and Infrared (IR) spectroscopy technique. The X-ray revealed the formation of nano-sized ferrite particles with cubic spinel structure and the cubic phase in the ferrite matrix. The IR shows the characteristic ferrite bonds were confirmed. The average crystalline particles sized were calculated by Scherrer formula. The average crystalline size obtained from XRD was found between 40 and 44nm. The lattice parameters, X-ray density and bond length are different parameters are calculated from XRD patterns. The UV-Visible Spectroscopy of prepared sample shows that the band gap energy in the range of semiconductor materials. The Coercivity was found to change in proportionally and sintering temperature with the particle sizes of the investigated ferrites.

Rathod, Sopan M.; Shinde, Ashok B.

2012-11-01

41

Study Of Structural And Dielectric Properties Of Ni-Mg Ferrite Nanoparticles  

Microsoft Academic Search

Ferrite nanoparticles of basic composition Ni0.7Mg0.3Fe2-xAlxO4 (0.0<=x<=0.5) were prepared through citrate gel method and characterized using XRD, TEM and dielectric spectroscopy techniques. The dielectric properties were studied as a function of frequency (42 Hz-5 MHz) at room temperature. The average particle size has been found between 8-17 nm. The dispersion in dielectric properties and ac conductivity (sigmaac), with frequency reveals

Razia Nongjai; Khalid Mujasam Batoo; Shakeel Khan

2010-01-01

42

Structure and magnetic properties of manganese-zinc-ferrites prepared by spray pyrolysis method  

NASA Astrophysics Data System (ADS)

A spray pyrolysis of a water solution of iron, manganese and iron nitrates is applied to prepare Zn0.5Mn0.5Fe2O4 single-phase ferrite with a spinel-type structure. The samples are characterized by means of differential scanning calorimetry, scanning and transmission electron microscopy, X-ray diffraction, infrared and 57Fe Mössbauer spectroscopy. The mass magnetization ? and the magnetic susceptibility 1/? of the ferrites are measured as a function of temperature over the range of 78-728 K. The obtained sample contains nanoparticles with an average diameter d ?7 nm possessing MnxZnyFe3-(x+y)O4 spinel-type structure with a uniform distribution of manganese and zinc atoms over the ferrite lattice. The Curie temperature is determined to be 375 ÷ 380 K.

Kotsikau, Dzmitry; Ivanovskaya, Maria; Pankov, Vladimir; Fedotova, Yulia

2015-01-01

43

Oriented attachment explains cobalt ferrite nanoparticle growth in bioinspired syntheses  

PubMed Central

Summary Oriented attachment has created a great debate about the description of crystal growth throughout the last decade. This aggregation-based model has successfully described biomineralization processes as well as forms of inorganic crystal growth, which could not be explained by classical crystal growth theory. Understanding the nanoparticle growth is essential since physical properties, such as the magnetic behavior, are highly dependent on the microstructure, morphology and composition of the inorganic crystals. In this work, the underlying nanoparticle growth of cobalt ferrite nanoparticles in a bioinspired synthesis was studied. Bioinspired syntheses have sparked great interest in recent years due to their ability to influence and alter inorganic crystal growth and therefore tailor properties of nanoparticles. In this synthesis, a short synthetic version of the protein MMS6, involved in nanoparticle formation within magnetotactic bacteria, was used to alter the growth of cobalt ferrite. We demonstrate that the bioinspired nanoparticle growth can be described by the oriented attachment model. The intermediate stages proposed in the theoretical model, including primary-building-block-like substructures as well as mesocrystal-like structures, were observed in HRTEM measurements. These structures display regions of substantial orientation and possess the same shape and size as the resulting discs. An increase in orientation with time was observed in electron diffraction measurements. The change of particle diameter with time agrees with the recently proposed kinetic model for oriented attachment. PMID:24605288

Hetaba, Walid; Wißbrock, Marco; Löffler, Stefan; Mill, Nadine; Eckstädt, Katrin; Dreyer, Axel; Ennen, Inga; Sewald, Norbert; Schattschneider, Peter; Hütten, Andreas

2014-01-01

44

Oriented attachment explains cobalt ferrite nanoparticle growth in bioinspired syntheses.  

PubMed

Oriented attachment has created a great debate about the description of crystal growth throughout the last decade. This aggregation-based model has successfully described biomineralization processes as well as forms of inorganic crystal growth, which could not be explained by classical crystal growth theory. Understanding the nanoparticle growth is essential since physical properties, such as the magnetic behavior, are highly dependent on the microstructure, morphology and composition of the inorganic crystals. In this work, the underlying nanoparticle growth of cobalt ferrite nanoparticles in a bioinspired synthesis was studied. Bioinspired syntheses have sparked great interest in recent years due to their ability to influence and alter inorganic crystal growth and therefore tailor properties of nanoparticles. In this synthesis, a short synthetic version of the protein MMS6, involved in nanoparticle formation within magnetotactic bacteria, was used to alter the growth of cobalt ferrite. We demonstrate that the bioinspired nanoparticle growth can be described by the oriented attachment model. The intermediate stages proposed in the theoretical model, including primary-building-block-like substructures as well as mesocrystal-like structures, were observed in HRTEM measurements. These structures display regions of substantial orientation and possess the same shape and size as the resulting discs. An increase in orientation with time was observed in electron diffraction measurements. The change of particle diameter with time agrees with the recently proposed kinetic model for oriented attachment. PMID:24605288

Wolff, Annalena; Hetaba, Walid; Wißbrock, Marco; Löffler, Stefan; Mill, Nadine; Eckstädt, Katrin; Dreyer, Axel; Ennen, Inga; Sewald, Norbert; Schattschneider, Peter; Hütten, Andreas

2014-01-01

45

Effect of Mg substitution on the magnetic properties of NiCuZn ferrite nanoparticles prepared through a novel method using egg white  

NASA Astrophysics Data System (ADS)

Nanocrystalline Mg-substituted NiCuZn ferrites were successfully synthesized, for the first time, by using metal nitrates and freshly extracted egg white. The thermal decomposition process of the nitrate-egg white precursors was investigated by thermogravimetric (TG) technique. X-ray diffraction (XRD) revealed that, single-phase cubic ferrites with average particle size of 23.9-35.1 nm were directly formed after ignition at 500 °C. No noticeable variation of lattice parameters with increasing magnesium content was observed, while X-ray densities were found to decrease. This can be explained on the basis of ionic radii and atomic masses of the substituted cation. Transmission electron microscope (TEM) shows that, particles are permanently magnetized and get agglomerated. The saturation magnetization ( M s) and coercivity ( H c) as a function of Mg content were investigated using vibrating sample magnetometer (VSM). It has been found that the M s increases firstly up to x=0.2 and then decreases, while H c continuously decreases. Magnetic susceptibility measurements give results which agree well with those obtained by VSM. The obvious decrease in the Curie temperature ( T C) with increasing Mg indicates that the ferrimagnetic grains are widely separated and enclosed by non-magnetic magnesium ions.

Gabal, M. A.

2009-10-01

46

Comparison of surface effects in SiO2 coated and uncoated nickel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Magnetic properties of uncoated and silica coated nickel ferrite nanoparticles of comparable sizes have been studied in detail. Silica coated and uncoated nanoparticles were prepared by sol-gel and co-precipitation methods, respectively. Average crystallite size determined by X-ray diffraction is 12 nm and 14 nm for the silica coated and uncoated nanoparticles, respectively. Normalized saturation magnetization value of the coated nanoparticles was found to be lower than of uncoated nanoparticles, while a comparable small coercivity is observed for both the samples. Zero field cooled/field cooled (ZFC/FC) measurements reveal that the average blocking temperature (TB) of coated nanoparticles is lower than of the uncoated nanoparticles and is shifted to lower temperatures at high field. Thermoremanent magnetization (TRM) measurement indicates that the relaxation of coated nanoparticles have not been influenced very much with increasing cooling field as compared to uncoated nanoparticles and is attributed to enhanced surface effects in coated nanoparticles. The main source of enhanced surface effects in the coated nanoparticles is foremost disordered surface spins due to silica matrix. Temperature dependent AC susceptibility exhibits two peaks for the coated nanoparticles' sample. First peak corresponds to blocking of huge core spin while second peak at lower temperature is may be due to enhanced surface effects (spin-glass behavior). All these findings such as lower saturation magnetization, faster shift of blocking temperature at high field, small effect of high magnetic field on magnetic relaxation, low temperature out-of-phase AC susceptibility peak for the coated nanoparticles signify enhanced surface effects in them as compared to uncoated nanoparticles.

Nadeem, K.; Krenn, H.; Sarwar, W.; Mumtaz, M.

2014-01-01

47

Influence of ferrite nanoparticle type and content on the crystallization kinetics and electroactive phase nucleation of poly(vinylidene fluoride).  

PubMed

This work reports on the nucleation of the ?-phase of poly(vinylidene fluoride) (PVDF) by incorporating CoFe(2)O(4) and NiFe(2)O(4) nanoparticles, leading in this way to the preparation of magnetoelectric composites. The fraction of filler nanoparticles needed to produce the same ?- to ?-phase ratio in crystallized PVDF is 1 order of magnitude lower in the cobalt ferrite nanoparticles. The interaction between nanoparticles and PVDF chains induce the all-trans conformation in PVDF segments, and this structure then propagates in crystal growth. The nucleation kinetics is enhanced by the presence of nanoparticles, as corroborated by the increasing number of spherulites with increasing nanoparticle content and by the variations of the Avrami's exponent. Further, the decrease of the crystalline fraction of PVDF with increasing nanoparticle content indicates that an important fraction of polymer chains are confined in interphases with the filler particle. PMID:21545124

Sencadas, Vitor; Martins, Pedro; Pitães, Alexandre; Benelmekki, Maria; Gómez Ribelles, José Luis; Lanceros-Mendez, Senentxu

2011-06-01

48

Study of Zn-Cu Ferrite Nanoparticles for LPG Sensing  

PubMed Central

Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. XRD patterns of different compositions of zinc-copper ferrite, Zn(1?x)CuxFe2O4 (x = 0.0, 0.25, 0.50, 0.75), revealed single phase inverse spinel ferrite in all the samples synthesized. With increasing copper concentration, the crystallite size was found to be increased from 28?nm to 47?nm. The surface morphology of all the samples studied by the Scanning Electron Microscopy there exhibits porous structure of particles throughout the samples. The pellets of the samples are prepared for LPG sensing characteristics. The sensing is carried out at different operating temperatures (200, 225, and 250°C) with the variation of LPG concentrations (0.2, 0.4, and 0.6 vol%). The maximum sensitivity of 55.33% is observed at 250°C operating for the 0.6 vol% LPG. PMID:23864833

Jain, Anuj; Baranwal, Ravi Kant; Bharti, Ajaya; Vakil, Z.; Prajapati, C. S.

2013-01-01

49

Study of Zn-Cu ferrite nanoparticles for LPG sensing.  

PubMed

Nanostructured zinc-copper mixed ferrite was synthesized using sol-gel method. XRD patterns of different compositions of zinc-copper ferrite, Zn(1-x)Cu(x)Fe2O4 (x = 0.0, 0.25, 0.50, 0.75), revealed single phase inverse spinel ferrite in all the samples synthesized. With increasing copper concentration, the crystallite size was found to be increased from 28?nm to 47?nm. The surface morphology of all the samples studied by the Scanning Electron Microscopy there exhibits porous structure of particles throughout the samples. The pellets of the samples are prepared for LPG sensing characteristics. The sensing is carried out at different operating temperatures (200, 225, and 250°C) with the variation of LPG concentrations (0.2, 0.4, and 0.6 vol%). The maximum sensitivity of 55.33% is observed at 250°C operating for the 0.6 vol% LPG. PMID:23864833

Jain, Anuj; Baranwal, Ravi Kant; Bharti, Ajaya; Vakil, Z; Prajapati, C S

2013-01-01

50

Preparation of substituted barium ferrite powders  

Microsoft Academic Search

Pure and (Co, Ti)-substituted Ba ferrites, produced by the citration process with the initial Fe to Ba ratio equal to 11.2, have been studied. The substitution x in Ba(Co, Ti)xFe12-xO19 has been varied from 0 to 1.1. The mechanism of the magnetic structure formation has been controlled by Mössbauer and infrared spectroscopy combined with magnetic susceptibility measurements. The substitution x

A. Grusková; J. Sláma; M. Michalíková; J. Lipka; I. Tóth; P. Kabos

1991-01-01

51

Magnetic properties of substituted strontium ferrite nanoparticles and thin films  

NASA Astrophysics Data System (ADS)

SrFe12-x(Zr0.5Mg0.5)xO19 nanoparticles and thin films with x=0-2.5 were synthesized by a sol-gel method on thermally oxidized silicon wafer (Si/SiO2). Structural and magnetic characteristics of synthesized samples were studied employing x-rays diffraction (XRD), transmission electron microscopy (TEM), magnetic susceptometer, atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and vibrating sample magnetometer (VSM). TEM micrographs display that the narrow size distribution of ferrite nanoparticles with average particle size of 50 nm were fabricated. Fitting obtained data of effective magnetic susceptibility by Vogel-Fulcher law confirms the existence of strong magnetic interaction among fine particles. XRD patterns and FE-SEM micrographs demonstrated that single phase c-axis hexagonal ferrite films with rather narrow grain size distribution were obtained. AFM micrographs exhibited that the surface roughness increases with an increase in Zr-Mg content. It was found from the VSM graphs that with an increase in substitution contents the coercivity decreases, while the saturation of magnetization increases. The Henkle plots confirms the existence of exchange coupling among nano-grain in ferrite thin films.

Ghasemi, Ali

2012-04-01

52

Preparation of highly anisotropic cobalt ferrite/silica microellipsoids using an external magnetic field.  

PubMed

Magnetic cobalt ferrite/silica microparticles having both an original morphology and an anisotropic nanostructure are synthesized through the use of an external magnetic field and nanoparticles characterized by a high magnetic anisotropy. The association of these two factors implies that the ESE (emulsion and solvent evaporation) sol-gel method employed here allows the preparation of silica microellipsoids containing magnetic nanoparticles aggregated in large chains. It is clearly shown that without this combination, microspheres characterized by an isotropic distribution of the magnetic nanoparticles are obtained. While the chaining of the cobalt ferrite nanoparticles inside the silica matrix is related to the increase of their magnetic dipolar interactions, the ellipsoidal shape of the microparticles may be explained by the elongation of the sol droplets in the direction of the external magnetic field during the synthesis. Because of their highly anisotropic structure, these microparticles exhibit permanent magnetic moments, which are responsible, at a larger scale, for the existence of strong magnetic dipolar interactions. Therefore, when they are dispersed in water, the microellipsoids self-assemble into large and irregular chains. These interactions can be reinforced by the use of external magnetic field, allowing the preparation of very large permanent chains. This research illustrates how nanostructured particles exhibiting complex architectures can be elaborated through simple, fast, and low-cost methods, such as the use of external fields in combination with soft chemistry. PMID:25029515

Abramson, Sébastien; Dupuis, Vincent; Neveu, Sophie; Beaunier, Patricia; Montero, David

2014-08-01

53

Barium ferrite powders prepared by microwave-induced hydrothermal reaction and magnetic property  

Microsoft Academic Search

We have prepared barium ferrite particles by the microwave-induced hydrothermal method. The crystallization of the barium ferrite particles is promoted within a short time by microwave irradiation because the seeds of barium ferrite having large permeability are rapidly heated through the interaction of barium ferrite with the magnetic component of the microwaves. Crystals having unusually low thickness were obtained compared

Tomohisa Yamauchi; Yasunori Tsukahara; Takao Sakata; Hirotaro Mori; Tsukasa Chikata; Shunsaku Katoh; Yuji Wada

2009-01-01

54

Influence of copper cations on the magnetic properties of NiCuZn ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Ni 0.6- xCu xZn 0.4Fe 2O 4 ( x=0-0.5) ferrite nanoparticles were prepared, employing a reverse micelle process. X-ray diffraction and transmission electron microscopy evaluations demonstrated that single phase spinel ferrites with narrow size distribution were obtained. Vibrating sample magnetometer was employed to probe the magnetic properties of the samples. It was found that with an increase in copper content, the saturation magnetization decreases. Magnetic dynamics of the samples was studied by measuring a.c. magnetic susceptibility versus temperature at different frequencies. The phenomenological Néel-Brown and Vogel-Fulcher models were employed to distinguish between the interacting or non-interacting systems. The system exhibits that there is strong interaction among fine particles.

Ghasemi, Ali; Ghasemi, Ebrahim; Paimozd, Ebrahim

2011-06-01

55

Influence of spherical assembly of copper ferrite nanoparticles on magnetic properties: orientation of magnetic easy axis.  

PubMed

The magnetic properties of copper ferrite (CuFe2O4) nanoparticles prepared via sol-gel auto combustion and facile solvothermal method are studied focusing on the effect of nanoparticle arrangement. Randomly oriented CuFe2O4 nanoparticles (NP) are obtained from the sol-gel auto combustion method, while the solvothermal method allows us to prepare iso-oriented uniform spherical ensembles of CuFe2O4 nanoparticles (NS). X-ray diffractometry (XRD), atomic absorption spectroscopy (AAS), infra-red (IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), (57)Fe Mössbauer spectroscopy and vibrating sample magnetometer (VSM) are used to investigate the composition, microstructure and magnetic properties of as-prepared ferrite nanoparticles. The field-dependent magnetization measurement for the NS sample at low temperature exhibits a step-like rectangular hysteresis loop (M(R)/M(S) ~ 1), suggesting cubic anisotropy in the system, whereas for the NP sample, typical features of uniaxial anisotropy (M(R)/M(S) ~ 0.5) are observed. The coercive field (HC) for the NS sample shows anomalous temperature dependence, which is correlated with the variation of effective anisotropy (K(E)) of the system. A high-temperature enhancement of H(C) and K(E) for the NS sample coincides with a strong spin-orbit coupling in the sample as evidenced by significant modification of Cu/Fe-O bond distances. The spherical arrangement of nanocrystals at mesoscopic scale provokes a high degree of alignment of the magnetic easy axis along the applied field leading to a step-like rectangular hysteresis loop. A detailed study on the temperature dependence of magnetic anisotropy of the system is carried out, emphasizing the influence of the formation of spherical iso-oriented assemblies. PMID:24714977

Chatterjee, Biplab K; Bhattacharjee, Kaustav; Dey, Abhishek; Ghosh, Chandan K; Chattopadhyay, Kalyan K

2014-06-01

56

Microwave characterization of magnetically hard and soft ferrite nanoparticles in K-band  

NASA Astrophysics Data System (ADS)

Nano-sized magnetic particles show great promise in improving the performance of microwave absorbers with respect to the corresponding bulk materials. In this paper, magnetically hard and soft ferrite nanoparticles (CoFe2O4 and Fe3O4) having an average size of 14 and 11 nm were prepared by co-precipitation method and characterized in terms of morphology, structure, and magnetic properties. Their permeability and permittivity were measured by a waveguide technique, embedding each sample in a host medium. Their parameters at microwave frequencies were retrieved by comparing different effective medium equations.

Della Pina, C.; Falletta, E.; Ferretti, A. M.; Ponti, A.; Gentili, G. G.; Verri, V.; Nesti, R.

2014-10-01

57

Preparation and magnetic properties of nano size nickel ferrite particles using hydrothermal method  

PubMed Central

Background Nickel ferrite, a kind of soft magnetic materials is one of the most attracting class of materials due to its interesting and important properties and has many technical applications, such as in catalysis, sensors and so on. In this paper the synthesis of NiFe2O4 nanoparticles by the hydrothermal method is reported and the inhibition of surfactant (Glycerol or Sodium dodecyl sulfate) on the particles growth is investigated. Methods For investigation of the inhibition effect of surfactant on NiFe2O4 particles growth, the samples were prepared in presence of Glycerol and Sodium dodecyl sulfate. The X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM) and inductively coupled plasma atomic emission spectrometer (ICP-AES) techniques were used to characterize the samples. Results The results of XRD and ICP-AES show that the products were pure NiFe2O4 and also nanoparticles grow with increasing the temperature, while surfactant prevents the particle growth under the same condition. The average particle size was determined from the Scherrer's equation and TEM micrographs and found to be in the range of 50-60 nm that decreased up to 10-15 nm in presence of surfactant. The FT-IR results show two absorption bands near to 603 and 490 cm-1 for the tetrahedral and octahedral sites respectively. Furthermore, the saturated magnetization and coercivity of NiFe2O4 nanoparticles were in the range of 39.60 emu/g and 15.67 Qe that decreased for samples prepared in presence of surfactant. As well as, the nanoparticles exhibited a superparamagnetic behavior at room temperature. Conclusions Nanosized nickel ferrite particles were synthesized with and without surfactant assisted hydrothermal methods. The results show that with increasing of temperature, the crystallinity of nanoparticles is increased. In the presence of surfactants, the crystallinity of NiFe2O4 nanoparticles decreased in comparison with surfactant- free prepared samples. All of the nickel ferrite nanoparticles were superparamagnetic at room temperature. Graphical abstract PMID:22462726

2012-01-01

58

The microstructure and characteristics of magnetite thin films prepared by ultrasound-enhanced ferrite plating  

Microsoft Academic Search

Summary form only given. In this study, magnetite (Fe3O4) thin films were prepared by ultrasound-enhanced ferrite plating. The effects of ferrite plating condition on the microstructure and magnetic properties of magnetite thin films were investigated.

Chun-Young Oh; Jae-Hee Oh; Tae-Kyung Ko

2002-01-01

59

Probing bismuth ferrite nanoparticles by hard x-ray photoemission: Anomalous occurrence of metallic bismuth  

SciTech Connect

We have investigated bismuth ferrite nanoparticles (?75?nm and ?155?nm) synthesized by a chemical method, using soft X-ray (1253.6?eV) and hard X-ray (3500, 5500, and 7500?eV) photoelectron spectroscopy. This provided an evidence for the variation of chemical state of bismuth in crystalline, phase pure nanoparticles. X-ray photoelectron spectroscopy analysis using Mg K? (1253.6?eV) source showed that iron and bismuth were present in both Fe{sup 3+} and Bi{sup 3+} valence states as expected for bismuth ferrite. However, hard X-ray photoelectron spectroscopy analysis of the bismuth ferrite nanoparticles using variable photon energies unexpectedly showed the presence of Bi{sup 0} valence state below the surface region, indicating that bismuth ferrite nanoparticles are chemically inhomogeneous in the radial direction. Consistently, small-angle X-ray scattering reveals a core-shell structure for these radial inhomogeneous nanoparticles.

Chaturvedi, Smita; Rajendra, Ranguwar; Ballav, Nirmalya; Kulkarni, Sulabha, E-mail: s.kulkarni@iiserpune.ac.in [Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pune 411008 (India); Sarkar, Indranil [DESY Photon Science, Deutsches Elektronen-Synchrotron, 22607 Hamburg (Germany); Shirolkar, Mandar M. [Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Jeng, U-Ser; Yeh, Yi-Qi [National Synchrotron Radiation Research Center, 101, Hsin-Ann Road, Science Park, Hsinchu 3007-6, Taiwan (China)

2014-09-08

60

Probing bismuth ferrite nanoparticles by hard x-ray photoemission: Anomalous occurrence of metallic bismuth  

NASA Astrophysics Data System (ADS)

We have investigated bismuth ferrite nanoparticles (˜75 nm and ˜155 nm) synthesized by a chemical method, using soft X-ray (1253.6 eV) and hard X-ray (3500, 5500, and 7500 eV) photoelectron spectroscopy. This provided an evidence for the variation of chemical state of bismuth in crystalline, phase pure nanoparticles. X-ray photoelectron spectroscopy analysis using Mg K? (1253.6 eV) source showed that iron and bismuth were present in both Fe3+ and Bi3+ valence states as expected for bismuth ferrite. However, hard X-ray photoelectron spectroscopy analysis of the bismuth ferrite nanoparticles using variable photon energies unexpectedly showed the presence of Bi0 valence state below the surface region, indicating that bismuth ferrite nanoparticles are chemically inhomogeneous in the radial direction. Consistently, small-angle X-ray scattering reveals a core-shell structure for these radial inhomogeneous nanoparticles.

Chaturvedi, Smita; Sarkar, Indranil; Shirolkar, Mandar M.; Jeng, U.-Ser; Yeh, Yi-Qi; Rajendra, Ranguwar; Ballav, Nirmalya; Kulkarni, Sulabha

2014-09-01

61

Magneto-optical waveguides made of cobalt ferrite nanoparticles embedded in silica\\/zirconia organic-inorganic matrix  

Microsoft Academic Search

This paper describes a way to develop magneto-optical waveguides via sol-gel process. They are made of cobalt ferrite nanoparticles embedded in a silica\\/zirconia matrix. Thin films are coated on glass substrate using the dip-coating technique. Annealing and UV treatment are applied to finalize sample preparation. Therefore, planar waveguides combining magneto-optical properties with a low refractive index (~1,5) are obtained. M-lines

Fadi Choueikani; François Royer; Damien Jamon; Ali Siblini; Jean Jacques Rousseau; Sophie Neveu; Jamal Charara

2009-01-01

62

Magnetic composites CoNi–barium ferrite prepared by electrodeposition  

Microsoft Academic Search

CoNi–barium ferrite magnetic composites have been prepared by using a chloride electroplating bath. The use of a cationic surfactant and a vigorous stirring of solution by means of a rod stirrer have been the key to assure a significant insertion of particles in the deposits. This incorporation was confirmed by chemical analysis, cross-section images and X-ray diffraction results. A maximum

E. Gómez; S. Pané; E. Vallés

2005-01-01

63

Electromagnetic properties of NiZn ferrite nanoparticles and their polymer composites  

SciTech Connect

The magnetic properties of polycrystalline NiZn ferrite nanoparticles synthesized using a polyol-reduction and coprecipitation reaction methods have been investigated. The effects on magnetization of synthesis approach, chemical composition, processing conditions, and on the size of nanoparticles on magnetization have been investigated. The measured room-temperature magnetization for the as-prepared magnetic nanoparticles (MNP) synthesized via polyol-reduction and coprecipitation is 69?Am{sup 2}?kg{sup ?1} and 14?Am{sup 2}?kg{sup ?1}, respectively. X-ray diffraction measurements confirm spinel structure of the particles with an estimated grain size of ?80?nm obtained from the polyol-reduction and 28?nm obtained from these coprecipitation techniques. Upon calcination under atmospheric conditions at different temperatures between 800?°C and 1000?°C, the magnetization, M, of the coprecipitated MNP increases to 76?Am{sup 2}?kg{sup ?1} with an estimated grain size of 90?nm. The MNP-polymer nanocomposites made from the synthesized MNP in various loading fraction and high density polyethylene exhibit interesting electromagnetic properties. The measured permeability and permittivity of the magnetic nanoparticle-polymer nanocomposites increases with the loading fractions of the magnetic nanoparticles, suggesting control for impedance matching for antenna applications.

Parsons, P. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States); Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Duncan, K. [U.S. Army, Communications-Electronics Research, Development and Engineering Center, Space and Terrestrial Communications Directorate, Aberdeen Proving Ground, Maryland 21005 (United States); Giri, A. K. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States); Bowhead Science and Technology, LLC, Belcamp, Maryland 21017 (United States); Xiao, J. Q. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States); Karna, S. P., E-mail: shashi.p.karna.civ@mail.mil [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States)

2014-05-07

64

Tuning the thermal relaxation of transition-metal ferrite nanoparticles through their intrinsic magnetocrystalline anisotropy  

E-print Network

constant in barium ferrite BaFe12O19 J. Appl. Phys. 110, 096107 (2011) Positive exchange bias in asTuning the thermal relaxation of transition-metal ferrite nanoparticles through their intrinsic at finite temperatures J. Appl. Phys. 110, 103906 (2011) Magnetic anisotropy and coercivity of Fe3Se4

Spinu, Leonard

65

Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer BiFeO{sub 3} (BFO) nanoparticles were grown by hydrothermal microwave method (HTMW). Black-Right-Pointing-Pointer The soaking time is effective in improving phase formation. Black-Right-Pointing-Pointer Rietveld refinement reveals an orthorhombic structure. Black-Right-Pointing-Pointer The observed magnetism of the BFO crystallites is a consequence of particle size. Black-Right-Pointing-Pointer The HTMW is a genuine technique for low temperatures and short times of synthesis. -- Abstract: Hydrothermal microwave method (HTMW) was used to synthesize crystalline bismuth ferrite (BiFeO{sub 3}) nanoparticles (BFO) in the temperature of 180 Degree-Sign C with times ranging from 5 min to 1 h. BFO nanoparticles were characterized by means of X-ray analyses, FT-IR, Raman spectroscopy, TG-DTA and FE-SEM. X-ray diffraction results indicated that longer soaking time was benefit to refraining the formation of any impurity phases and growing BFO crystallites into almost single-phase perovskites. Typical FT-IR spectra for BFO nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH{sup -} groups, commonly found in materials obtained by HTMW process. Compared with the conventional solid-state reaction process, submicron BFO crystallites with better homogeneity could be produced at the temperature as low as 180 Degree-Sign C. These results show that the HTMW synthesis route is rapid, cost effective, and could be used as an alternative to obtain BFO nanoparticles in the temperature of 180 Degree-Sign C for 1 h.

Biasotto, G. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)] [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil); Simoes, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista-Unesp, Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333, Bairro Pedregulho, CEP 12516-410, Guaratingueta, SP (Brazil); Foschini, C.R.; Zaghete, M.A.; Varela, J.A.; Longo, E. [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)] [Laboratorio Interdisciplinar em Ceramica (LIEC), Departamento de Fisico-Quimica, Instituto de Quimica, UNESP, CEP 14800-900, Araraquara, SP (Brazil)

2011-12-15

66

Maximizing Hysteretic Losses in Magnetic Ferrite Nanoparticles via Model-Driven Synthesis and Materials Optimization  

E-print Network

This article develops a set of design guidelines for maximizing heat dissipation characteristics of magnetic ferrite MFe[subscript 2]O[subscript 4] (M = Mn, Fe, Co) nanoparticles in alternating magnetic fields. Using ...

Chen, Ritchie

67

Direct dyes removal using modified magnetic ferrite nanoparticle  

PubMed Central

The magnetic adsorbent nanoparticle was modified using cationic surface active agent. Zinc ferrite nanoparticle and cetyl trimethylammonium bromide were used as an adsorbent and a surface active agent, respectively. Dye removal ability of the surface modified nanoparticle as an adsorbent was investigated. Direct Green 6 (DG6), Direct Red 31 (DR31) and Direct Red 23 (DR23) were used. The characteristics of the adsorbent were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of adsorbent dosage, initial dye concentration and salt was evaluated. In ternary system, dye removal of the adsorbent at 90, 120, 150 and 200 mg/L dye concentration was 63, 45, 30 and 23% for DR23, 97, 90, 78 and 45% for DR31 and 51, 48, 42 and 37% for DG6, respectively. It was found that dye adsorption onto the adsorbent followed Langmuir isotherm. The adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. PMID:24991427

2014-01-01

68

Structural and electrical properties of neodymium substituted cobalt ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

A series of polycrystalline spinel ferrites with composition CoFe2-xNdxO4(x=0.0, 0. 05, 0.1, 0.15, 0.2, 0.25) have been synthesized by sol gel method. The structural characterizations of the prepared samples were done using XRD and TEM. The crystallite size shows an increase with the increase in the concentration of neodymium. The activation energy has been calculated from the temperature dependent DC conductivity measurements. The dielectric properties were studied and analyzed as a function of frequency. All the samples exhibit normal dielectric behaviour which is attributed to Maxwell- Wagner interfacial polarization.

Xavier, S.; Thankachan, S.; Jacob, B. P.; Mohammed, E. M.

2015-02-01

69

Cellular Uptake and Biocompatibility of Bismuth Ferrite Harmonic Advanced Nanoparticles  

E-print Network

Bismuth Ferrite (BFO) nanoparticles (BFO-NP) display interesting optical (nonlinear response) and magnetic properties which make them amenable for bio-oriented applications as intra- and extra membrane contrast agents. Due to the relatively recent availability of this material in well dispersed nanometric form, its biocompatibility was not known to date. In this study, we present a thorough assessment of the effects of in vitro exposure of human adenocarcinoma (A549), lung squamous carcinoma (NCI-H520), and acute monocytic leukemia (THP-1) cell lines to uncoated and poly(ethylene glycol)-coated BFO-NP in the form of cytotoxicity, haemolytic response and biocompatibility. Our results support the attractiveness of the functional-BFO towards biomedical applications focused on advanced diagnostic imaging.

Staedler, Davide; Magouroux, Thibaud; Rogov, Andrii; Maguire, Ciaran Manus; Mohamed, Bashir M; Schwung, Sebastian; Rytz, Daniel; Jüstel, Thomas; Hwu, Stéphanie; Mugnier, Yannick; Dantec, Ronan Le; Volkov, Yuri; Gerber-Lemaire, Sandrine; Prina-Melloc, Adriele; Bonacina, Luigi; Wolf, Jean-Pierre

2014-01-01

70

Experimental studies of cobalt ferrite nanoparticles doped silica matrix 3D magneto-photonic crystals  

NASA Astrophysics Data System (ADS)

In this paper, we present the synthesis and the optical properties of 3D magneto-photonic structures. The elaboration process consists in firstly preparing then infiltrating polystyrene direct opals with a homogeneous solution of sol-gel silica precursors doped by cobalt ferrite nanoparticles, and finally dissolving the polystyrene spheres. Scanning Electron Microscopy (SEM) images of the prepared samples clearly evidence a periodic arrangement. Using a home-made polarimetric optical bench, the transmittance as a function of the wavelength, the Faraday rotation as a function of the applied magnetic field, and the Faraday ellipticity as a function of the wavelength and as a function of the applied magnetic field were measured. The existence of deep photonic band gaps (PBG), the unambiguous magnetic character of the samples and the qualitative modification of the Faraday ellipticity in the area of the PBG are evidenced.

Abou Diwan, E.; Royer, F.; Kekesi, R.; Jamon, D.; Blanc-Mignon, M. F.; Neveu, S.; Rousseau, J. J.

2013-05-01

71

Microstructural and Mössbauer properties of low temperature synthesized Ni-Cd-Al ferrite nanoparticles  

PubMed Central

We report the influence of Al3+ doping on the microstructural and Mössbauer properties of ferrite nanoparticles of basic composition Ni0.2Cd0.3Fe2.5 - xAlxO4 (0.0 ? x ? 0.5) prepared through simple sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray, transmission electron microscopy (TEM), Fourier transformation infrared (FTIR), and Mössbauer spectroscopy techniques were used to investigate the structural, chemical, and Mössbauer properties of the grown nanoparticles. XRD results confirm that all the samples are single-phase cubic spinel in structure excluding the presence of any secondary phase corresponding to any structure. SEM micrographs show the synthesized nanoparticles are agglomerated but spherical in shape. The average crystallite size of the grown nanoparticles was calculated through Scherrer formula and confirmed by TEM and was found between 2 and 8 nm (± 1). FTIR results show the presence of two vibrational bands corresponding to tetrahedral and octahedral sites. Mössbauer spectroscopy shows that all the samples exhibit superparamagnetism, and the quadrupole interaction increases with the substitution of Al3+ ions. PMID:21851597

2011-01-01

72

[Investigation of the interaction between DNA and cobalt ferrite nanoparticles by FTIR spectroscopy].  

PubMed

The interaction of DNA with nanoparticles of cobalt ferrite powder prepared by the mechano-chemical method was studied. It was shown that CoFe(2)O(4) nanoparticles efficiently bind DNA in aqueous solutions (Tris-HCl), forming a bionanocomposite. The adsorption capacity of CoFe(2)O(4) nanoparticles for DNA was evaluated to be 5.25 x 10(-3) mol/m(2). The desorption of DNA from the surface of the particles was analyzed while changing the pH, the ionic strength, and the chemical content of the medium. The DNA-CoFe(2)O(4) nanocomposite was investigated by FTIR spectroscopy. The block of the data allowed one to consider the mechanism of the interaction between a polynucleotide and CoFe(2)O(4) nanoparticles and to make the assumption that the binding occurred due to the coordination interaction of the phosphate groups and heterocyclic bases of DNA (oxygen atoms of thymine and guanine) with metal ions on the particle surface. The analysis of the IR spectra showed that binding can lead to the partial destabilization of the DNA structure, with the B conformation of a polynucleotide being preserved. PMID:19915646

Pershina, A G; Sazonov, A E; Ogorodova, L M

2009-01-01

73

Magnetic properties of cobalt-ferrite nanoparticles embedded in polystyrene resin  

SciTech Connect

Samples of maghemite and cobalt-ferrite nanoparticles (sizes, 3-10 nm) were prepared by cross-linking sulfonated polystyrene resin with aqueous solutions of (1) FeCl{sub 2}, (2) 80%FeCl{sub 2}+20%CoCl{sub 2}, (3) FeCl{sub 3}, and (4) 80%FeCl{sub 3}+20%CoCl{sub 2} by volume. Chemical analysis, x-ray powder-diffraction, and {sup 57}Fe Moessbauer spectroscopic measurements show that samples 1 and 3 consist of {gamma}-Fe{sub 2}O{sub 3} nanoparticles (sizes, {approx}10 and 3 nm) and sample 2 and 4 consist of Co{sub x}Fe{sub 3-x}O{sub 4} nanoparticles (sizes, {approx}10 and 4 nm). The temperature dependence of the zero-field-cooled and field-cooled magnetizations at low temperatures, together with a magnetic hysteresis in the M versus H data below blocking temperatures, demonstrate superparamagnetic behavior. The introduction of Co in the iron oxide-resin matrix results in an increase in the blocking temperature of nanoparticles.

Vaishnava, P. P.; Senaratne, U.; Buc, E.; Naik, R.; Naik, V. M.; Tsoi, G.; Wenger, L. E.; Boolchand, P. [Kettering University, Flint, Michigan 48504 (United States); Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States); University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); University of Alabama, Birmingham, Alabama 35294 (United States); Department of ECECS, University of Cincinnati, Ohio 45221 (United States)

2006-04-15

74

The role of multi-walled carbon nanotubes on the magnetic and reflection loss characteristics of substituted strontium ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Substituted strontium ferrite SrFe12-x(Ni0.5Mn0.5Zr)x/2O19/multi-walled carbon nanotubes (MWCNTs) composites were prepared by a sol-gel method. X-ray diffraction patterns confirm the formation of single phase ferrite nanoparticle and nanocomposites of ferrite/carbon nanotubes. Fourier transform infrared spectroscopy demonstrates the existence of functional groups on the surface of carbon nanotubes. Superconducting quantum interference device measurements showed that the values of specific saturation magnetization increases, while coercivity decreases with an increase in substitution content. Zero field cooled magnetization and field cooled magnetization curves display that with an increase in substitution content, the blocking temperature increases. Field emission scanning electron microscopy micrographs demonstrate that ferrite nanoparticles were attached on external surfaces of the carbon nanotubes. The investigation of the microwave absorption indicates that with an addition of carbon nanotubes, the real and imaginary parts of permittivity and reflection loss enhanced. It is found that with increasing the thickness of absorbers, the resonance frequencies shift to lower regime.

Ghasemi, Ali

2013-03-01

75

The effect of starting materials and preparation process on the properties of magnesium ferrite pigment  

Microsoft Academic Search

Purpose – To prepare of fine particle size magnesium ferrite pigments by sol-gel method. Design\\/methodology\\/approach – Different magnesium ferrite pigments with stoichiometric ratios were prepared by sol-gel and dispersion methods. The characterisation of magnesium ferrite pigments were based on X-ray diffraction, transmission electron microscope, particle size distribution, thermal and magnetometric analyses. Findings – The type of polymer and the starting

F. F. Abdel-Mohsen; H. S. Emira

2005-01-01

76

Nickel zinc ferrites prepared by the citrate precursor method  

NASA Astrophysics Data System (ADS)

Ni 1- xZn xFe 2O 4 ( x=0.2, 0.4, 0.5, 0.6 and 0.7) were prepared by a combustion method. The precursors for the solids were different gels obtained from metal nitrates and citric acid by a sol-process. The gels thus obtained were heated at 200°C and they exhibited self-propagating combustion behavior. The residues were heated for 2 h at 1000°C. XRD analysis of the intermediates and final solids revealed that, after combustion, the gel is directly transformed into single-phased, nano-sized Ni,Zn ferrite particles. The sintering processes increased the crystallinity of the solids and the domain sizes. Lattice parameters also increase with the increment of x. The insertion of small amounts of different R(III) cations (R=Ruthenium, Yttrium and rare-earth cations) into a nickel zinc ferrite (Ni 0.5Zn 0.5Fe 2O 4) has been also investigated. XRD studies have been carried out in order to determine if the R(III) cations enter the spinel structure. Samples with several Ni 0.5Zn 0.5Fe 2- y R yO 4 compositions were prepared by the auto-combustion method. In all cases, XRD measurements show distortions in the spinel cell and, in some cases, the formation of various rare earth iron oxides.

Sileo, Elsa E.; Rotelo, Ramiro; Jacobo, Silvia E.

2002-07-01

77

Low temperature polymer assisted hydrothermal synthesis of bismuth ferrite nanoparticles  

Microsoft Academic Search

BFO nanoparticles were successfully synthesized by a polymer assisted hydrothermal method at a temperature as low as 160°C. The as-prepared powders, characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM), exhibited a pure BFO phase about 10nm size and uniform sphere-like shape. It was found that the added polymer played a key role in decreasing the growing speed of

Yonggang Wang; Gang Xu; Zhaohui Ren; Xiao Wei; Wenjian Weng; Piyi Du; Ge Shen; Gaorong Han

2008-01-01

78

Preparation of transparent conductors ferroelectric memory materials and ferrites  

DOEpatents

A process for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Bhattacharya, Raghu Nath (Littleton, CO); Ginley, David S. (Evergreen, CO)

1998-01-01

79

Preparation of transparent conductors ferroelectric memory materials and ferrites  

DOEpatents

A process is described for the preparation by electrodeposition of metal oxide film and powder compounds for ferroelectric memory materials and ferrites wherein the metal oxide includes a plurality of metals. The process comprises providing an electrodeposition bath, providing soluble salts of the metals to this bath, electrically energizing the bath to thereby cause formation of a recoverable film of metal on the electrode, recovering the resultant film as a film or a powder, and recovering powder formed on the floor of the bath. The films and powders so produced are subsequently annealed to thereby produce metal oxide for use in electronic applications. The process can be employed to produce metal-doped metal oxide film and powder compounds for transparent conductors. The process for preparation of these metal-doped metal oxides follows that described above.

Bhattacharya, R.N.; Ginley, D.S.

1998-07-28

80

Embryotoxicity of cobalt ferrite and gold nanoparticles: a first in vitro approach.  

PubMed

Nanoparticles (NPs) are emerging as promising biomedical tools thanks to their peculiar characteristics. Our purpose was to investigate the embryotoxicity of cobalt ferrite and gold NPs through the Embryonic Stem Cell Test (EST). The EST is an in vitro standard assay, which permits to classify substances as strongly, weakly or non-embryotoxic. Due to the particular physical-chemical nature of nanoparticles, we introduced a modification to the standard protocol exposing the Embryonic Stem Cells (ES-D3) to nanoparticles only during the first 5 days of the assay. Moreover, we proposed a method to discriminate and compare the embryotoxicity of the substances within the weakly embryotoxic range. Our ID(50) results permit to classify cobalt ferrite nanoparticles coated with gold and silanes as non-embryotoxic. The remaining nanoparticles have been classified as weakly embryotoxic in this decreasing order: gold salt (HAuCl(4).3H(2)O)>cobalt ferrite salt (CoFe(2)O(4))>cobalt ferrite nanoparticles coated with silanes (Si-CoFe)>gold nanoparticles coated with hyaluronic acid (HA-Au). PMID:20566333

Di Guglielmo, Claudia; López, David Ramos; De Lapuente, Joaquín; Mallafre, Joan Maria Llobet; Suàrez, Miquel Borràs

2010-09-01

81

Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

In the present work, cobalt ferrite nanoparticles (CoFe2O4 NPs) have been synthesized by combustion method. The surface of the CoFe2O4 NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe2O4 NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe2O4 NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe2O4 NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe2O4 NPs up to 1.8 mg mL-1 when tested with mouse fibroblast L929 cell line.

Salunkhe, A. B.; Khot, V. M.; Thorat, N. D.; Phadatare, M. R.; Sathish, C. I.; Dhawale, D. S.; Pawar, S. H.

2013-01-01

82

Structural and magnetic properties correlated with cation distribution of Mo-substituted cobalt ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Mo-substituted cobalt ferrite nanoparticles; CoFe2-2xMoxO4 (0.0?x?0.3) were prepared by a one-step solution combustion synthesis technique. The reactants were metal nitrates and glycine as a fuel. The samples were characterized using an X-ray diffraction (XRD), a transmission electron microscope (TEM) and a vibrating sample magnetometer (VSM). XRD analysis revealed a pure single phase of cubic spinel ferrites for all samples with x up to 0.3. The lattice parameter decreases with Mo6+ substitution linearly up to x=0.15, then nonlinearly for x?0.2. Rietveld analysis and saturation magnetization (Ms) revealed that Mo6+ replaced Fe3+ in the tetrahedral A-sites up to x=0.15, then it replaced Fe3+ in both A-sites and B-sites for x?0.2. The saturation magnetization (Ms) increases with increasing Mo6+ substitution up to x=0.15 then decreases. The crystallite size decreased while the microstrain increased with increasing Mo6+ substitution. Inserting Mo6+ produces large residents of defects and cation vacancies.

Heiba, Z. K.; Mostafa, Nasser Y.; Abd-Elkader, Omar H.

2014-11-01

83

Microwave Absorption Properties of Mn–Co–Sn Doped Barium Ferrite Nanoparticles  

Microsoft Academic Search

Substituted barium ferrite BaFe9(Mn0.5Co0.5Sn)3\\/2O19 was prepared by sol-gel method. X-ray diffraction (XRD), transmission electron microscope (TEM), AC susceptometer, vibrating sample magnetometer (VSM) and vector network analyzer were used to analyze the structure, static and dynamic magnetic properties of the prepared samples. The prepared ferrite particles possess irregular non spherical shape with a broad size distribution. The substitution was very effective

Ali Ghasemi; Vladimir Sepelak; Xiaoxi Liu; Akimitsu Morisako

2009-01-01

84

Rod-shaped polyaniline barium ferrite nanocomposite: preparation, characterization and properties  

Microsoft Academic Search

Rod-shaped polyaniline (PANI)-barium ferrite nanocomposite was synthesized by in situ polymerization of aniline in the presence of BaFe12O19 nanoparticles with diameters of 60-80 nm. The structure, morphology and properties of the nanocomposite were measured using powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. Different ferrite\\/PANI ratios were selected in order to

Yuanxun Li; Huaiwu Zhang; Yingli Liu; Qiye Wen; Jie Li

2008-01-01

85

Nanocrystalline structure and magnetic properties of barium ferrite particles prepared via glycine as a fuel  

Microsoft Academic Search

The barium ferrite particles were prepared using a self-propagating combustion method with glycine as a fuel. The process was investigated with differential scanning calorimeter and thermogravimetric analysis. The effects of the pH value of the precursor solution, the glycine dosage and calcination temperature on the morphology, the crystalline structure and the magnetic properties of the barium ferrite particles were studied

Jianxun Qiu; Le Liang; Mingyuan Gu

2005-01-01

86

Synthesis of shape controlled ferrite nanoparticles by sonochemical technique.  

PubMed

Synthesis of magnetic iron oxides/ferrites in the nano scale by sonochemical synthesis has become prominent recently. This technique facilitates the synthesis of magnetic particles in the nano scale attributed to the hotspot mechanism arising due to acoustic cavitation induced chemical reaction. Generally volatile organometallic precursor compounds favoring the formation of fully amorphous particles have been used to synthesize various nano magnetic materials. We report here the synthesis of ultrafine, < 10 nm magnetic iron oxide nanoparticles by sonochemical technique starting with a non-volatile precursor iron salt such as iron citrate which seems to favor the formation of semi crystalline/crystalline particles as the reaction takes place either in the interfacial region or in the bulk solution. Mono dispersed, ultra fine, approximately 4 nm spherical shaped magnetic maghemite particles having a saturation magnetization of 58.2 emu/g and coercivity of 118 Oe were obtained at low values of pH, 10 while higher pH, 11-13 favored the formation of elongated, cylindrical, acicular particles with a reduced magnetization. The coercivity was also found to decrease with increasing pH, with it being 118 Oe at pH 10 and 3 Oe at pH 13. When the ultrasound amplitude/intensity was low, 38% heat treatment of the samples at 300 degrees C (at pH 10) was required to make them crystalline, while application of high intensity ultrasound, 50% amplitude served as a single step mechanism for obtaining crystalline maghemite particles. The maghemite particles obtained at a pH of 10 could find applications in information storage media. PMID:19049216

Theerdhala, Sriharsha; Alhat, Devendra; Vitta, Satish; Bahadur, D

2008-08-01

87

Zinc ferrite nanoparticle as a magnetic catalyst: Synthesis and dye degradation  

SciTech Connect

Graphical abstract: Photocatalytic degradation of Reactive Red 198 and Reactive Red 120 by the synthesized zinc ferrite nanoparticle. - Highlights: • Magnetic zinc ferrite nanoparticle was synthesized and characterized. • Photocatalytic dye degradation by magnetic nanoparticle was studied. • Formate, acetate and oxalate were detected as dominant dye degradation aliphatic intermediates. • Nitrate and sulfate ions were detected as mineralization products of dyes. • Zinc ferrite nanoparticle was an effective magnetic photocatalyst to degrade dyes. - Abstract: In this paper, magnetic zinc ferrite (ZnFe{sub 2}O{sub 4}) nanoparticle was synthesized and its photocatalytic dye degradation ability from colored wastewater was studied. Reactive Red 198 (RR198) and Reactive Red 120 (RR120) were used as model dyes. The characteristics of ZnFe{sub 2}O{sub 4} were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Photocatalytic dye degradation by ZnFe{sub 2}O{sub 4} was studied by UV–vis spectrophotometer and ion chromatography (IC). The effects of ZnFe{sub 2}O{sub 4} dosage, initial dye concentration and salt on dye degradation were evaluated. Formate, acetate and oxalate anions were detected as dominant aliphatic intermediate. Inorganic anions (nitrate and sulfate anions) were detected as dye mineralization products. The results indicated that ZnFe{sub 2}O{sub 4} could be used as a magnetic photocatalyst to degrade dyes from colored wastewater.

Mahmoodi, Niyaz Mohammad, E-mail: mahmoodi@icrc.ac.ir

2013-10-15

88

Synthesis of core/shell spinel ferrite/carbon nanoparticles with enhanced cycling stability for lithium ion battery anodes.  

PubMed

Monodispersed core/shell spinel ferrite/carbon nanoparticles are formed by thermolysis of metal (Fe3+, Co2+) oleates followed by carbon coating. The phase and morphology of nanoparticles are characterized by x-ray diffraction and transmission electron microscopy. Pure Fe3O4 and CoFe2O4 nanoparticles are initially prepared through thermal decomposition of metal–oleate precursors at 310 degrees C and they are found to exhibit poor electrochemical performance because of the easy aggregation of nanoparticles and the resulting increase in the interparticle contact resistance. In contrast, uniform carbon coating of Fe3O4 and CoFe2O4 nanoparticles by low-temperature (180 degrees C) decomposition of malic acid allowed each nanoparticle to be electrically wired to a current collector through a conducting percolative path. Core/shell Fe3O4/C and CoFe2O4/C nanocomposite electrodes show a high specific capacity that can exceed 700 mAh g(-1) after 200 cycles, along with enhanced cycling stability. PMID:22414887

Jin, Yun-Ho; Seo, Seung-Deok; Shim, Hyun-Woo; Park, Kyung-Soo; Kim, Dong-Wan

2012-03-30

89

Induction of apoptosis in cancer cells by NiZn ferrite nanoparticles through mitochondrial cytochrome C release  

PubMed Central

The long-term objective of the present study was to determine the ability of NiZn ferrite nanoparticles to kill cancer cells. NiZn ferrite nanoparticle suspensions were found to have an average hydrodynamic diameter, polydispersity index, and zeta potential of 254.2 ± 29.8 nm, 0.524 ± 0.013, and ?60 ± 14 mV, respectively. We showed that NiZn ferrite nanoparticles had selective toxicity towards MCF-7, HepG2, and HT29 cells, with a lesser effect on normal MCF 10A cells. The quantity of Bcl-2, Bax, p53, and cytochrome C in the cell lines mentioned above was determined by colorimetric methods in order to clarify the mechanism of action of NiZn ferrite nanoparticles in the killing of cancer cells. Our results indicate that NiZn ferrite nanoparticles promote apoptosis in cancer cells via caspase-3 and caspase-9, downregulation of Bcl-2, and upregulation of Bax and p53, with cytochrome C translocation. There was a concomitant collapse of the mitochondrial membrane potential in these cancer cells when treated with NiZn ferrite nanoparticles. This study shows that NiZn ferrite nanoparticles induce glutathione depletion in cancer cells, which results in increased production of reactive oxygen species and eventually, death of cancer cells. PMID:24204141

Al-Qubaisi, Mothanna Sadiq; Rasedee, Abdullah; Flaifel, Moayad Husein; Ahmad, Sahrim Hj; Hussein-Al-Ali, Samer; Hussein, Mohd Zobir; Zainal, Zulkarnain; Alhassan, Fatah H; Taufiq-Yap, Yun H; Eid, Eltayeb EM; Arbab, Ismail Adam; Al-Asbahi, Bandar A; Webster, Thomas J; Zowalaty, Mohamed Ezzat El

2013-01-01

90

Static and dynamic magnetic properties of Co 2 Z barium ferrite nanoparticle composites  

Microsoft Academic Search

The static, dynamic and attenuation properties of Co2Z barium ferrites and Co2Z composites have been studied. The results showed that both static and dynamic magnetic properties are significantly different for large particles and nanoparticles. As compared to large particles, Co2Z nanoparticles have a small saturation magnetization Ms, large coercivity Hc, small permeability µ'0 and µ''max, but high resonance frequency fR.

Z. W. Li; L. Chen; C. K. Ong; Z. Yang

2005-01-01

91

Magnetic, dielectric and sensing properties of manganese substituted copper ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Manganese substituted copper ferrite nanoparticles were synthesized by an auto-combustion technique using metal nitrates and urea for gas sensor application. The products were characterized by XRD, SEM, EDX, TEM and VSM techniques. The effect of annealing temperature on the particle size, magnetic and dielectric properties of Mn-Cu ferrite nanoparticles was analyzed. The size of the particles are in the range of ~9-45 nm. The effect of annealing on the magnetic properties is discussed with the help of variation in saturation magnetization (Ms) and coercivity (Hc) by vibrating sample magnetometer (VSM). The dielectric loss and dielectric constant have been measured in the frequency range of 100 kHz-5 MHz. Furthermore, Conductance response of Mn-Cu ferrite nanomaterial was measured by exposing the material to reducing gas like liquefied petroleum gas (LPG).

Kumar, E. Ranjith; Jayaprakash, R.; Devi, G. Sarala; Reddy, P. Siva Prasada

2014-04-01

92

SAXS study of hexagonal W-type barium ferrite nanoparticles  

Microsoft Academic Search

Hexagonal ferrites are a wide family of ferromagnetic oxides, with peculiar and useful properties. The crystal structure of the different known types of hexagonal ferrites (M, W, X, Y, Z and U) is very complex and can be considered as a superposition of R and S blocks along the hexagonal c axis, RSR*S*for M-typeand RSSR*S*S*forW-type, whereR is a three-oxygen-layerblock with

A. Wacha; L. Trif; Z. Varga; G. Goerigk; A. B ´ ota; U. Vainio

93

Frequency-Dependent Magnetic Susceptibility of Magnetite and Cobalt Ferrite Nanoparticles Embedded in PAA Hydrogel.  

PubMed

Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network. PMID:23673482

van Berkum, Susanne; Dee, Joris T; Philipse, Albert P; Erné, Ben H

2013-01-01

94

Frequency-Dependent Magnetic Susceptibility of Magnetite and Cobalt Ferrite Nanoparticles Embedded in PAA Hydrogel  

PubMed Central

Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network. PMID:23673482

van Berkum, Susanne; Dee, Joris T.; Philipse, Albert P.; Erné, Ben H.

2013-01-01

95

Assessment of cytotoxicity and oxidative effect of Bismuth Ferrite (BFO) harmonic nanoparticles for localized DNA photo-interaction  

NASA Astrophysics Data System (ADS)

Bismuth Ferrite nanoparticles have been recently used to selectively interact with malignant cell DNA via in situ generated second harmonic in a novel theranostics protocol [Nanoscale 6(5), pp. 2929, 2014]. In this report, we extend the screening of biocompatibility of BFO uncoated uncoated nanoparticles and assess the nanoparticle- mediated production of reactive oxygen species as a function of excitation wavelength.

Staedler, Davide; Magouroux, Thibaud; Passemard, Solène; Ciepielewski, Daniel; Gerber-Lemaire, Sandrine; Wolf, Jean-Pierre; Bonacina, Luigi

2014-09-01

96

Magnetic and catalytic properties of copper ferrite nanopowders prepared by combustion process.  

PubMed

Copper ferrite nano-particles with Fe/Cu ratios varying from 2 to 12 were successfully synthesized by combustion process using copper nitrate, iron nitrate and urea. The resultant powders were investigated by scanning electron microscopy (SEM), vibrating sample magnetometer (VSM). The results revealed that the copper ferrite powders are uniform in the range of 250-300 nm. The copper ferrite with Fe/Cu ratio of 2 possessed a saturation magnetization of 5.47 emu/g, and an intrinsic coercive force of 241.98 Oe, with Fe/Cu ratio of 12 possessed a saturation magnetization of 22.06 emu/g and an intrinsic coercive force of 247.94 Oe. Moreover, these copper ferrite magnetic nano-particles also acted as catalyst for the oxidation of 2,3,6-trimethylphenol to synthesize 2,3,5-trimethylhydrogenquinone and 2,3,5-trimethyl-1,4-benzoquinone for the first time. The conversion of 2,3,6-trimethylphenol in the kinetic behavior of oxidation was investigated in detail. The reaction shows dramatically enhanced by the addition of copper-ferrite nano-particles to the solution. PMID:19441554

Liu, B L; Fu, Y P; Wang, M L

2009-02-01

97

Preparation of DPPE-Stabilized Gold Nanoparticles  

ERIC Educational Resources Information Center

An experiment is presented that introduces students to nanotechnology through the preparation of nanoparticles and their visualization using transmission electron microscopy (TEM). The experiment familiarizes the students with nonaqueous solvents, biphasic reactions, phase-transfer agents, ligands to stabilize growing nanoparticles, and bidentate…

Dungey, Keenan E.; Muller, David P.; Gunter, Tammy

2005-01-01

98

Maximizing hysteretic losses in magnetic ferrite nanoparticles via model-driven synthesis and materials optimization.  

PubMed

This article develops a set of design guidelines for maximizing heat dissipation characteristics of magnetic ferrite MFe2O4 (M = Mn, Fe, Co) nanoparticles in alternating magnetic fields. Using magnetic and structural nanoparticle characterization, we identify key synthetic parameters in the thermal decomposition of organometallic precursors that yield optimized magnetic nanoparticles over a wide range of sizes and compositions. The developed synthetic procedures allow for gram-scale production of magnetic nanoparticles stable in physiological buffer for several months. Our magnetic nanoparticles display some of the highest heat dissipation rates, which are in qualitative agreement with the trends predicted by a dynamic hysteresis model of coherent magnetization reversal in single domain magnetic particles. By combining physical simulations with robust scalable synthesis and materials characterization techniques, this work provides a pathway to a model-driven design of magnetic nanoparticles tailored to a variety of biomedical applications ranging from cancer hyperthermia to remote control of gene expression. PMID:24016039

Chen, Ritchie; Christiansen, Michael G; Anikeeva, Polina

2013-10-22

99

Structure of Oxide Nanoparticles in Fe-16Cr MA/ODS Ferritic Steel  

SciTech Connect

Oxide nanoparticles in Fe-16Cr ODS ferritic steel fabricated by mechanical alloying (MA) method have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. A partial crystallization of oxide nanoparticles was frequently observed in as-fabricated ODS steel. The crystal structure of crystalline oxide particles is identified to be mainly Y{sub 4}Al{sub 2}O{sub 9} (YAM) with a monoclinic structure. Large nanoparticles with a diameter larger than 20 nm tend to be incoherent and have a nearly spherical shape, whereas small nanoparticles with a diameter smaller than 10 nm tend to be coherent or semi-coherent and have faceted boundaries. The oxide nanoparticles become fully crystallized after prolonged annealing at 900 C. These results lead us to propose a three-stage formation mechanism of oxide nanoparticles in MA/ODS steels.

Hsiung, L; Fluss, M; Kimura, A

2010-04-06

100

Iron-based soft magnetic composites with MnZn ferrite nanoparticles coating obtained by solgel method  

E-print Network

by the powder metallurgy (PM) methods. SMCs have unique magnetic properties, such as a three-dimen- sional (3DIron-based soft magnetic composites with Mn­Zn ferrite nanoparticles coating obtained by sol focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn­Zn ferrite

Volinsky, Alex A.

101

New methods for lipid nanoparticles preparation.  

PubMed

Lipid nanoparticles have attracted many researchers during recent years due to the excellent tolerability and advantages compared to liposomes and polymeric nanoparticles. High pressure homogenization is the main technique used to prepare solid lipid nanoparticles (SLN) encapsulating different type of drugs, however this method involves some critical process parameters. For this reason and in order to overcome patented methods, different production techniques for lipid nanoparticles have been widely investigated in recent years (last decade). The paper reviews new methods for lipid nanoparticles preparation, and their recent applications in pharmaceutical field, especially focusing on coacervation, microemulsions templates, supercritical fluid technology, phase-inversion temperature (PIT) techniques. References of the most relevant literature and patents published by various research groups on these fields are provided. PMID:21834772

Corrias, Francesco; Lai, Francesco

2011-09-01

102

Preparation of electrophoretic nanoparticles for electronic paper.  

PubMed

As an electronic alternative for printed media, the E-paper has ultralow power consumption, reduced eyestrain, high contrast ratio. Electrophoretic displays are one of the most promising E-paper technologies, which are now widely used in consumer products. The properties of the electrophoretic display are mainly determined by the composition, size, light scattering properties, and density of the electrophoretic nanoparticles. First, we introduce the preparation of white and black electrophoretic nanoparticles, because the monochrome E-paper has achieved commercial success. Then the structure and properties of color electrophoretic nanoparticles for color E-paper products are discussed. In addition, the enhanced and novel electrophoretic nanoparticles are now propelling the development of next-generation E-paper with new applications. Finally, the active area of the preparation of electrophoretic nanoparticles is highlighted in terms of the development of future E-paper. PMID:24749445

Meng, Xianwei; Qiang, Li; Wei, Jianfei; Shi, Haitang

2014-02-01

103

Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles  

SciTech Connect

Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

Mukherjee, A., E-mail: soumen.basu@phy.nitdgp.ac.in; Banerjee, M., E-mail: soumen.basu@phy.nitdgp.ac.in; Basu, S., E-mail: soumen.basu@phy.nitdgp.ac.in [Department of Physics, National Institute of Technology, Durgapur-713209 (India); Pal, M. [CSIR-Central Mechanical Engineering Research Institute, Durgapur-713209 (India)

2014-04-24

104

Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Multiferroic bismuth ferrite (BFO) and gadolinium (Gd) doped bismuth ferrite had been synthesized by a sol-gel method. Particle size had been estimated by Transmission electron microscopy (TEM) and found to decrease with Gd doping. We studied the temperature and frequency dependence of impedance and electric modulus and calculated the grain and grain boundary resistance and capacitance of the investigated samples. We observed that electrical activation energy increases for all the doped samples. Optical band gap also increases for the doped samples which can be used in photocatalytic application of BFO.

Mukherjee, A.; Banerjee, M.; Basu, S.; Pal, M.

2014-04-01

105

Preparation and performance of NiCuZn-CO 2Z composite ferrite material  

NASA Astrophysics Data System (ADS)

Low-temperature fired composite ferrite ceramic materials were obtained by mixing fine-grained NiCuZn and CO 2Z prepared by the sol-gel method with appropriate amounts of sintering aids and then sintering at a low temperature of 890°C for 4 h. The composite ferrites have relatively high initial permeability ( ?=50), high cut-off frequency ( fr=120 MHz) and high resistivity ( ?>10 10 ? cm). The influences of different composition and various sintering aids on the properties of the low-temperature sintered composite ferrite were investigated. The microstructures of the sintered ceramics were observed and analyzed by SEM.

Qu, Weiguo; Wang, XiaoHui; Li, Longtu

2003-02-01

106

Galactosylated manganese ferrite nanoparticles for targeted MR imaging of asialoglycoprotein receptor  

NASA Astrophysics Data System (ADS)

Cancer cells can express specific biomarkers, such as cell membrane proteins and signaling factors. Thus, finding biomarkers and delivering diagnostic agents are important in the diagnosis of cancer. In this study, we investigated a biomarker imaging agent for the diagnosis of hepatic cancers. The asialoglycoprotein receptor (ASGPr) was selected as a biomarker for hepatoma cells and the ASGPr-targetable imaging agent bearing a galactosyl group was prepared using manganese ferrite nanoparticles (MFNP) and galactosylgluconic acid. The utility of the ASGPr-targetable imaging agent, galactosylated MFNP (G-MFNP) was assessed by several methods in ASGPr-expressing HepG2 cells as target cells and ASGPr-deficient MCF7 cells. Physical and chemical properties of G-MFNP were examined using Fourier-transform infrared spectroscopy, dynamic light scattering, zeta potential analysis, and transmission electron microscopy. No significant cytotoxicity was observed in either cell line. Targeting ability was assessed using flow cytometry, magnetic resonance imaging, inductively coupled plasma atomic emission spectroscopy, absorbance analysis, dark-field microscopy, Prussian blue staining, and transmission electron microscopy. We demonstrated that G-MFNP target successfully and bind to ASGPr-expressing HepG2 cells specifically. We suggest that these results will be useful in strategies for cancer diagnoses based on magnetic resonance imaging.

Yang, Seung-Hyun; Heo, Dan; Lee, Eugene; Kim, Eunjung; Lim, Eun-Kyung; Lee, Young Han; Haam, Seungjoo; Suh, Jin-Suck; Huh, Yong-Min; Yang, Jaemoon; Park, Sahng Wook

2013-11-01

107

Study Of Structural And Dielectric Properties Of Ni-Mg Ferrite Nanoparticles  

SciTech Connect

Ferrite nanoparticles of basic composition Ni{sub 0.7}Mg{sub 0.3}Fe{sub 2-x}Al{sub x}O{sub 4}(0.0{<=}x{<=}0.5) were prepared through citrate gel method and characterized using XRD, TEM and dielectric spectroscopy techniques. The dielectric properties were studied as a function of frequency (42 Hz-5 MHz) at room temperature. The average particle size has been found between 8-17 nm. The dispersion in dielectric properties and ac conductivity ({sigma}{sub ac}), with frequency reveals that the dispersion is due to Maxwell-Wagner type of interfacial polarization in general and the hopping of charge between Fe{sup 2+} and Fe{sup 3+} as well as between Ni{sup 2+} and Ni{sup 3+} ions at B-sites. The dielectric loss tangent (tan {delta}) shows abnormal behavior for the compositions 0.3, 0.4 and 0.5 which has been explained in the light of Rezlescue model.

Nongjai, Razia; Batoo, Khalid Mujasam; Khan, Shakeel [Dept. of Applied Physics, Aligarh Muslim University, Aligarh, 202002 (India) and King Abdullah Institute for Nanotechnology, King Saud University, Riyadh, 11451 (Saudi Arabia)

2010-12-01

108

Manifestation of weak ferromagnetism and photocatalytic activity in bismuth ferrite nanoparticles  

SciTech Connect

Bismuth ferrite (BFO) nanoparticles were synthesized by auto-ignition technique with and without adding ignition fuel such as citric acid. The presence of citric acid in the reaction mixture yielded highly-magnetic BFO/{gamma}-Fe{sub 2}O{sub 3} nanocomposite. When this composite was annealed to 650 Degree-Sign C, a single phase BFO was formed with average crystallite size of 50 nm and showed weak ferromagnetic behavior. Conversely, the phase pure BFO prepared without adding citric acid exhibited antiferromagnetism because of its larger crystallite size of around 70 nm. The visible-light driven photocatalytic activity of both the pure BFO and BFO/{gamma}-Fe{sub 2}O{sub 3} nanocomposite were examined by degrading methyl orange dye. The pure BFO showed a moderate photocatalytic activity; while BFO/{gamma}-Fe{sub 2}O{sub 3} nanocomposite showed enhanced activity. This could be probably due to the optimal band gap ratio between BFO and {gamma}-Fe{sub 2}O{sub 3} phases reduced the recombination of electron-hole pairs which aided in the enhancement of photocatalytic activity.

Sakar, M.; Balakumar, S. [National Center for Nanoscience and Nanotechnology, University of Madras, Chennai - 600025 (India); Saravanan, P. [Advanced Magnetics Group, Defence Metallurgical Research Laboratory, Hyderabad - 500 058 (India); Jaisankar, S. N. [Polymer Lab, Central Leather Research Laboratory, Adyar, Chennai - 600020 (India)

2013-02-05

109

Magnetic Silver-Coated Ferrite Nanoparticles and Their Application in Thick Films  

NASA Astrophysics Data System (ADS)

Magnetic silver-coated ferrite nanoparticles with 39.8% weight gain (relative to ferrite nanopowder coated by a silver layer) were synthesized by electroless deposition of silver on ferrite nanopowder. The mechanism of the electroless deposition was explored in terms of pretreatment, sensitization, activation, and the reduction of silver-ammonia complexes. Experiments showed that the optimal deposition conditions were a temperature of 50°C, pH value of 10 to 12, duration of 65 min with ethanol plus polyethylene glycol as additives, and ultrasonic vibration as a method of dispersing the nanoparticles. From transmission electron microscopy (TEM) images, it was observed that as-synthesized nanoparticles had a core-shell structure with a particle size of 35 nm to 90 nm and a shell thickness of 5 nm to 20 nm. X-ray diffraction (XRD) analysis confirmed that only ferrite and metallic silver were present in the product. Electrical resistance and magnetic hysteresis measurements demonstrated that the nanoparticles were both electrically conductive (volume electrical resistivity on the order of 10-4 ? cm to 10-3 ? cm when compressed to pressure of 2 × 10 6 Pa) and possessed ferrimagnetic properties. After a thick-film paste, obtained with the nanoparticles as the functional phase, was directly written and sintered, scanning electron microscopy (SEM) analysis and electrical resistance measurements of conductive lines in the acquired array pattern showed that an electrically conductive network with some defects and cavities was formed, with a volume electrical resistivity of 1 × 10-4 ? cm to 1 × 10-3 ? cm.

Liu, Jianguo; Huang, Baling; Li, Xiangyou; Li, Ping; Zeng, Xiaoyan

2010-12-01

110

Preparation of core shell particles consisting of cobalt ferrite and silica by sol–gel process  

Microsoft Academic Search

Core shell particles consisting of a magnetic core of cobalt ferrite (CoFe2O4) and a shell of silica (SiO2) are prepared by sol–gel process using tetraethylorthosilicate (TEOS) as a precursor of silica, and metallic nitrates as precursors of ferrite. The core shell structure is confirmed by TEM. The magnetic properties of these nanocomposites are measured by PPMS in low temperature and

Shuping Zhang; Dawei Dong; Yu Sui; Zhiguo Liu; Hongxia Wang; Zhengnan Qian; Wenhui Su

2006-01-01

111

Preparation and characterisation of magnetically ordered columnar structures of barium ferrite particles  

Microsoft Academic Search

In this study, we report on the columnar structures of barium ferrite particles that were prepared from water suspensions by applying a magnetic field during drying. Commercial barium ferrite (BaFe12O19) monodomain particles were used, and the surfaces of the particles were treated with an organic surfactant to reduce their agglomeration. The columnar structures were obtained by drying the water suspensions

Svetoslav Kolev; Darja Lisjak; Miha Drofenik

2011-01-01

112

Preparation and magnetic properties of composite powders of hollow microspheres coated with barium ferrite  

Microsoft Academic Search

The composites of barium ferrite coated on hollow ceramic microspheres are successfully prepared using sol–gel combustion method. The crystal structure and magnetic properties with different weight ratio of hollow microspheres in the composite are studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC)\\/DTA and vibrating sample magnetometry (VSM). The results show that the composites are composed of barium ferrite and

Guohong Mu; Xifeng Pan; Haigen Shen; Mingyuan Gu

2007-01-01

113

Mössbauer spectroscopy, magnetic characteristics, and reflection loss analysis of nickel-strontium substituted cobalt ferrite nanoparticles  

SciTech Connect

In current research work, Co{sub 1-x}Ni{sub x/2}Sr{sub x/2}Fe{sub 2}O{sub 4} (x?=?0–1 in a step of 0.2) ferrite nanoparticles were synthesized by a sol-gel method. According to the evolution in the subspectral areas obtained from Mössbauer spectroscopy, it was found that the relaxing iron belongs mostly to the site B, since the Mössbauer fraction of site A does not vary appreciably. With an increase in Ni-Sr substitution contents in cobalt ferrite, the coercivity and saturation of magnetization decrease. Variation of reflection loss versus frequency in microwave X-band demonstrates that the reflection peak shifts to lower frequency by adding substituted cations and the synthesized nanoparticles can be considered for application in electromagnetic wave absorber technology.

Ghasemi, Ali, E-mail: ali13912001@yahoo.com [Materials Engineering Department, Malek Ashtar University of Technology, Shahin Shahr (Iran, Islamic Republic of); Paesano, Andrea; Cerqueira Machado, Carla Fabiana [Departamento de Física, Centro de Ciências Exatas, Universidade Estadual de Maringá, Maringá (Brazil); Shirsath, Sagar E. [Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad (India); Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano (Japan); Liu, Xiaoxi; Morisako, Akimitsu [Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano (Japan)

2014-05-07

114

Enhanced Néel temperature in Mn ferrite nanoparticles linked to growth-rate-induced cation inversion  

Microsoft Academic Search

Mn ferrite (MnFe2O4) nanoparticles, having diameters from 4 to 50 nm, were synthesized using a modified co-precipitation technique in which mixed metal chloride solutions were added to different concentrations of boiling NaOH solutions to control particle growth rate. Thermomagnetization measurements indicated an increase in Néel temperature corresponding to increased particle growth rate and particle size. The Néel temperature is also

Aria Yang; C. N. Chinnasamy; J. M. Greneche; Yajie Chen; Soack D. Yoon; Zhaohui Chen; Kailin Hsu; Zhuhua Cai; Kate Ziemer; C. Vittoria; V. G. Harris

2009-01-01

115

Faraday rotation of cobalt ferrite nanoparticle polymer composite films at cryogenic temperatures.  

PubMed

This paper investigates the behavior of the Verdet constant for cobalt ferrite (CoFe?O?) nanoparticles polymer composite films at low temperatures using a 532 nm laser source. An experimental setup for Faraday rotation (FR) at low temperatures is introduced and FRs were measured at various temperatures. Verdet constants were deduced from the paramagnetic model for terbium gallium garnet glass where ~4× improvement was observed at 40° K for CoFe?O? composite film. PMID:24787165

Demir, Veysi; Gangopadhyay, Palash; Norwood, Robert A; Peyghambarian, Nasser

2014-04-01

116

Method to prepare nanoparticles on porous mediums  

DOEpatents

A method to prepare porous medium decorated with nanoparticles involves contacting a suspension of nanoparticles in an ionic liquid with a porous medium such that the particles diffuse into the pores of the medium followed by heating the resulting composition to a temperature equal to or greater than the thermal decomposition temperature of the ionic liquid resulting in the removal of the liquid portion of the suspension. The nanoparticles can be a metal, an alloy, or a metal compound. The resulting compositions can be used as catalysts, sensors, or separators.

Vieth, Gabriel M. (Knoxville, TN) [Knoxville, TN; Dudney, Nancy J. (Oak Ridge, TN) [Oak Ridge, TN; Dai, Sheng (Knoxville, TN) [Knoxville, TN

2010-08-10

117

Morphology of cobalt ferrite nanoparticle-polyelectrolyte multilayered nanocomposites  

NASA Astrophysics Data System (ADS)

Novel magnetic nanocomposite films with controlled morphology were produced via the electrostatic layer-by-layer assembly of cationic CoFe 2O 4 nanoparticles and anionic poly(3,4-ethylenedioxy thiophene)/poly(styrene sulfonic acid) (PEDOT:PSS) complex. The electrostatic interaction between nanoparticle and the polyelectrolyte complex ensured a stepwise growth of the nanocomposite film with virtually identical amounts of materials being adsorbed at each deposition cycle as observed by UV-vis spectroscopy. AFM images acquired under the tapping mode revealed a globular morphology with dense and continuous layers of nanoparticles with voids being filled with polymeric material.

Alcantara, G. B.; Paterno, L. G.; Fonseca, F. J.; Morais, P. C.; Soler, M. A. G.

2011-05-01

118

Effects of magnetic cobalt ferrite nanoparticles on biological and artificial lipid membranes  

PubMed Central

Background The purpose of this work is to provide experimental evidence on the interactions of suspended nanoparticles with artificial or biological membranes and to assess the possibility of suspended nanoparticles interacting with the lipid component of biological membranes. Methods 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid vesicles and human red blood cells were incubated in suspensions of magnetic bare cobalt ferrite (CoFe2O4) or citric acid (CA)-adsorbed CoFe2O4 nanoparticles dispersed in phosphate-buffered saline and glucose solution. The stability of POPC giant unilamellar vesicles after incubation in the tested nanoparticle suspensions was assessed by phase-contrast light microscopy and analyzed with computer-aided imaging. Structural changes in the POPC multilamellar vesicles were assessed by small angle X-ray scattering, and the shape transformation of red blood cells after incubation in tested suspensions of nanoparticles was observed using scanning electron microscopy and sedimentation, agglutination, and hemolysis assays. Results Artificial lipid membranes were disturbed more by CA-adsorbed CoFe2O4 nanoparticle suspensions than by bare CoFe2O4 nanoparticle suspensions. CA-adsorbed CoFe2O4-CA nanoparticles caused more significant shape transformation in red blood cells than bare CoFe2O4 nanoparticles. Conclusion Consistent with their smaller sized agglomerates, CA-adsorbed CoFe2O4 nanoparticles demonstrate more pronounced effects on artificial and biological membranes. Larger agglomerates of nanoparticles were confirmed to be reactive against lipid membranes and thus not acceptable for use with red blood cells. This finding is significant with respect to the efficient and safe application of nanoparticles as medicinal agents. PMID:24741305

Drašler, Barbara; Drobne, Damjana; Novak, Sara; Valant, Janez; Boljte, Sabina; Otrin, Lado; Rappolt, Michael; Sartori, Barbara; Igli?, Aleš; Kralj-Igli?, Veronika; Šuštar, Vid; Makovec, Darko; Gyergyek, Sašo; Ho?evar, Matej; Godec, Matjaž; Zupanc, Jernej

2014-01-01

119

Bacterially synthesized ferrite nanoparticles for magnetic hyperthermia applications.  

PubMed

Magnetic hyperthermia uses AC stimulation of magnetic nanoparticles to generate heat for cancer cell destruction. Whilst nanoparticles produced inside magnetotactic bacteria have shown amongst the highest reported heating to date, these particles are magnetically blocked so that strong heating occurs only for mobile particles, unless magnetic field parameters are far outside clinical limits. Here, nanoparticles extracellularly produced by the bacteria Geobacter sulfurreducens are investigated that contain Co or Zn dopants to tune the magnetic anisotropy, saturation magnetization and nanoparticle sizes, enabling heating within clinical field constraints. The heating mechanisms specific to either Co or Zn doping are determined from frequency dependent specific absorption rate (SAR) measurements and innovative AC susceptometry simulations that use a realistic model concerning clusters of polydisperse nanoparticles in suspension. Whilst both particle types undergo magnetization relaxation and show heating effects in water under low AC frequency and field, only Zn doped particles maintain relaxation combined with hysteresis losses even when immobilized. This magnetic heating process could prove important in the biological environment where nanoparticle mobility may not be possible. Obtained SARs are discussed regarding clinical conditions which, together with their enhanced MRI contrast, indicate that biogenic Zn doped particles are promising for combined diagnostics and cancer therapy. PMID:25232657

Céspedes, Eva; Byrne, James M; Farrow, Neil; Moise, Sandhya; Coker, Victoria S; Bencsik, Martin; Lloyd, Jonathan R; Telling, Neil D

2014-11-01

120

Control of the Size of Cobalt Ferrite Nanoparticles : Synthesis and Properties  

Microsoft Academic Search

The preparation of a fluid of cobalt ferrite particles having a size varying from 2 to 5nm is described. This bas been achieved by using functionalized surfactants. The size of cobalt femte particles decreases when the total reactant concentration decreases. The magnetic properties are described with magnetization curves and \\

M. P. Pileni; N. Moumen; J. F. Hochepied; P. Bonville; P. Veillet

1997-01-01

121

Bacterially synthesized ferrite nanoparticles for magnetic hyperthermia applications  

NASA Astrophysics Data System (ADS)

Magnetic hyperthermia uses AC stimulation of magnetic nanoparticles to generate heat for cancer cell destruction. Whilst nanoparticles produced inside magnetotactic bacteria have shown amongst the highest reported heating to date, these particles are magnetically blocked so that strong heating occurs only for mobile particles, unless magnetic field parameters are far outside clinical limits. Here, nanoparticles extracellularly produced by the bacteria Geobacter sulfurreducens are investigated that contain Co or Zn dopants to tune the magnetic anisotropy, saturation magnetization and nanoparticle sizes, enabling heating within clinical field constraints. The heating mechanisms specific to either Co or Zn doping are determined from frequency dependent specific absorption rate (SAR) measurements and innovative AC susceptometry simulations that use a realistic model concerning clusters of polydisperse nanoparticles in suspension. Whilst both particle types undergo magnetization relaxation and show heating effects in water under low AC frequency and field, only Zn doped particles maintain relaxation combined with hysteresis losses even when immobilized. This magnetic heating process could prove important in the biological environment where nanoparticle mobility may not be possible. Obtained SARs are discussed regarding clinical conditions which, together with their enhanced MRI contrast, indicate that biogenic Zn doped particles are promising for combined diagnostics and cancer therapy.Magnetic hyperthermia uses AC stimulation of magnetic nanoparticles to generate heat for cancer cell destruction. Whilst nanoparticles produced inside magnetotactic bacteria have shown amongst the highest reported heating to date, these particles are magnetically blocked so that strong heating occurs only for mobile particles, unless magnetic field parameters are far outside clinical limits. Here, nanoparticles extracellularly produced by the bacteria Geobacter sulfurreducens are investigated that contain Co or Zn dopants to tune the magnetic anisotropy, saturation magnetization and nanoparticle sizes, enabling heating within clinical field constraints. The heating mechanisms specific to either Co or Zn doping are determined from frequency dependent specific absorption rate (SAR) measurements and innovative AC susceptometry simulations that use a realistic model concerning clusters of polydisperse nanoparticles in suspension. Whilst both particle types undergo magnetization relaxation and show heating effects in water under low AC frequency and field, only Zn doped particles maintain relaxation combined with hysteresis losses even when immobilized. This magnetic heating process could prove important in the biological environment where nanoparticle mobility may not be possible. Obtained SARs are discussed regarding clinical conditions which, together with their enhanced MRI contrast, indicate that biogenic Zn doped particles are promising for combined diagnostics and cancer therapy. Electronic supplementary information (ESI) available: Further details of the cluster model of polydisperse nanoparticles used for the AC susceptibility simulations (Fig. S1 to S3). Examples of the heating curves and the linear fit used to determine the SAR values are shown in Fig. S4. Fig. S5 exhibits the energy loss per mass of iron during magnetic hyperthermia (from SAR values) normalized to H2 and frequency for further comparison among samples. Fig. S6 shows the comparison between the simulations of AC susceptibility spectra including regions below and above the experimental frequency range for MNA, Zn0.2 and Zn0.4 nanoparticles suspended in solvents with different viscosities (water, glycerol and a hypothetical high viscous solvent). Fig. S7 exhibits a comparison among the simulated ?'' susceptibility of MNA, Zn0.2 and Zn0.4 nanoparticles (a) in water and (b) in glycerol. See DOI: 10.1039/c4nr03004d

Céspedes, Eva; Byrne, James M.; Farrow, Neil; Moise, Sandhya; Coker, Victoria S.; Bencsik, Martin; Lloyd, Jonathan R.; Telling, Neil D.

2014-10-01

122

Rod-shaped polyaniline-barium ferrite nanocomposite: preparation, characterization and properties.  

PubMed

Rod-shaped polyaniline (PANI)-barium ferrite nanocomposite was synthesized by in situ polymerization of aniline in the presence of BaFe(12)O(19) nanoparticles with diameters of 60-80 nm. The structure, morphology and properties of the nanocomposite were measured using powder x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometry. Different ferrite/PANI ratios were selected in order to study magnetic and conductive properties. The results indicated that there were some interactions between PANI chains and ferrite particles. The saturation magnetization and the coercivity varied with the ferrite content. The conductivity at room temperature decreased from 43.35 to 6.9 × 10(-2) S cm(-1) when the ferrite content changed from 0 to 50 wt%. The composite has excellent electromagnetic parameters which indicates potential application in high performance adsorbing materials in broadband and high frequency ranges. The polymerization mechanism and interactions in the nanocomposites were also studied. PMID:21817707

Li, Yuanxun; Zhang, Huaiwu; Liu, Yingli; Wen, Qiye; Li, Jie

2008-03-12

123

Preparation and characterization of Mg nanoparticles  

SciTech Connect

In this paper, Mg nanoparticles were prepared in tetrahydrofuran via lithium reduction of the corresponding Mg salt. X-ray diffraction and scanning electron microscope investigations confirm the formation of hexagonal phase Mg particles with an average size of 300 nm. X-ray photoelectron spectrometer analysis indicates that the as-prepared Mg nanoparticles are covered with a protecting layer consisting of residue solvents, naphthalene and Mg(OH){sub 2}, which slows down further oxidation under ambient conditions. Thermal analysis shows that the rapid oxidation and nitridation processes of the particles take place at around 500 deg. C and 553 deg. C, respectively. Furthermore, the addition of a small amount of magnesium nanoparticles remarkably catalyzes the decomposition process of ammonium perchlorate by lowering the decomposition temperature and enhancing its heat output.

Song Meirong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Laboratory for Special Functionary Materials, Henan University, Kaifeng, 475001 (China); Graduate School of the Chinese Academy of Sciences, Beijing, 100049 (China); Chen Miao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)], E-mail: miaochen@lzb.ac.cn; Zhang Zhijun [Laboratory for Special Functionary Materials, Henan University, Kaifeng, 475001 (China)

2008-05-15

124

Preparation of Acicular Barium Ferrite Particles and Their Magnetic Properties  

Microsoft Academic Search

Methods for producing acicular barium ferrite particles for use in coated tape media were studied, and their magnetic and other properties were investigated. Acicular ¿-FeOOH particles were dispersed in a BaCl2 solution, and NaHCO3 added to precipitate BaCO3 on the particle surfaces. After washing and addition of B2O3, P2O5, or Bi2O3, particles were fired at 800 to 900°C; addition of

M. Sugimoto; Y. Arai; H. Harada; T. Nukui

1985-01-01

125

Barium ferrite powders prepared by milling and annealing  

Microsoft Academic Search

Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment. Design\\/methodology\\/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were

R. Nowosielski; R. Babilas; G. Dercz; J. Wrona

126

Structural, magnetic, dielectric and optical properties of nickel ferrite nanoparticles synthesized by co-precipitation method  

NASA Astrophysics Data System (ADS)

Nickel ferrite nanoparticles were synthesized by wet chemical co-precipitation method and the corresponding temperature dependent structural, magnetic and optical properties of these nanoparticles have been investigated. X-ray diffraction patterns show the single phase cubic spinal crystal structure belonging to the space group Fd3m. The average crystallite size varies in the range 8-20 nm with varying sintering temperature. Raman spectroscopy exhibits a doublet-like peak behaviour which indicates the presence of mixed spinel structure. The saturation magnetization, coercivity and remanence increase with increasing sintering temperature from 250 to 550 °C. The non-saturation and low values of magnetization at high fields indicate the strong surface effects to magnetization in NiFe2O4 nanoparticles. The g-value calculated from electron spin resonance spectrum indicates the transfer of divalent metallic ion from octahedral to tetrahedral site (i.e. mixed spinel structure). The dielectric permittivity, loss tangent and ac conductivity measurements show strong temperature dependence at all frequencies. The observed ac conductivity response suggests that the conduction in ferrite nanoparticles is due to feeble polaron hopping between Fe3+/Fe2+ ions. Room temperature UV-vis diffuse spectra indicate that NiFe2O4 is an indirect band gap material with band gap ranges from 1.27 to 1.47 eV with varying sintering temperature. The photoluminescence study clearly indicates that the Ni2+ ions occupy both octahedral and tetrahedral sites confirming mixed spinel structure.

Joshi, Seema; Kumar, Manoj; Chhoker, Sandeep; Srivastava, Geetika; Jewariya, Mukesh; Singh, V. N.

2014-11-01

127

Retsch PM400 ball mill Nanoparticle preparation  

E-print Network

Retsch PM400 ball mill pump Nanoparticle preparation Ball Milling Method Physically grind micron size feedstock down to the nanoscale regime using planetary ball milling with WC balls Particles them from unwanted oxidation Particle Characterization Chemical composition: XPS, FTIR, TGA Particle

Anderson, Scott L.

128

Effects of pH and citric acid content on the structure and magnetic properties of MnZn ferrite nanoparticles synthesized by a sol-gel autocombustion method  

NASA Astrophysics Data System (ADS)

MnZn ferrite nanoparticles have been synthesized by a sol-gel autocombustion technique with different pHs of 0, 5 and 7 and different citric acid to metal nitrate (CA/MN) molar ratios of 0.25, 0.5 and 1. The crystallite size, microstructure and magnetic properties were studied using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry methods. The results showed that the single phase MnZn ferrite could be achieved directly without any post-calcination using pH of 7 and CA/MN molar ratio of 0.5. MnZn ferrite nanoparticles prepared by pH=7 and CA/MN=0.5 with the crystallite size of 39 nm exhibited saturation magnetization of 20.9 emu/g and coercivity of 44 Oe.

Seyyed Ebrahimi, S. A.; Masoudpanah, S. M.

2014-05-01

129

Online monitoring of cell metabolism to assess the toxicity of nanoparticles: the case of cobalt ferrite.  

PubMed

Different in vitro assays are successfully used to determine the relative cytotoxicity of a broad range of compounds. Nevertheless, different research groups have pointed out the difficulty in using the same tests to assess the toxicity of nanoparticles (NPs). In this study, we evaluated the possible use of a microphysiometer, Bionas 2500 analyzing system Bionas GmbH®, to detect in real time changes in cell metabolisms linked to NPs exposure. We focused our work on response changes of fibroblast cultures linked to exposure by cobalt ferrite NPs and compared the results to conventional in vitro assays. The measurements with the microphysiometer showed a cobalt ferrite cytotoxic effect, confirmed by the Colony Forming Efficiency assay. In conclusion, this work demonstrated that the measurement of metabolic parameters with a microphysiometer is a promising method to assess the toxicity of NPs and offers the advantage to follow on-line the cell metabolic changes. PMID:21495878

Mariani, Valentina; Ponti, Jessica; Giudetti, Guido; Broggi, Francesca; Marmorato, Patrick; Gioria, Sabrina; Franchini, Fabio; Rauscher, Hubert; Rossi, François

2012-05-01

130

HRTEM Study of Oxide Nanoparticles in K3-ODS Ferritic Steel Developed for Radiation Tolerance  

SciTech Connect

Crystal and interfacial structures of oxide nanoparticles and radiation damage in 16Cr-4.5Al-0.3Ti-2W-0.37 Y{sub 2}O{sub 3} ODS ferritic steel have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. Oxide nanoparticles with a complex-oxide core and an amorphous shell were frequently observed. The crystal structure of complex-oxide core is identified to be mainly monoclinic Y{sub 4}Al{sub 2}O{sub 9} (YAM) oxide compound. Orientation relationships between the oxide and the matrix are found to be dependent on the particle size. Large particles (> 20 nm) tend to be incoherent and have a spherical shape, whereas small particles (< 10 nm) tend to be coherent or semi-coherent and have a faceted interface. The observations of partially amorphous nanoparticles and multiple crystalline domains formed within a nanoparticle lead us to propose a three-stage mechanism to rationalize the formation of oxide nanoparticles containing core/shell structures in as-fabricated ODS steels. Effects of nanoparticle size and density on cavity formation induced by (Fe{sup 8+} + He{sup +}) dual-beam irradiation are briefly addressed.

Hsiung, L; Fluss, M; Tumey, S; Kuntz, J; El-Dasher, B; Wall, M; Choi, W; Kimura, A; Willaime, F; Serruys, Y

2009-11-02

131

Pr3+-substituted W-type barium ferrite: Preparation and electromagnetic properties  

Microsoft Academic Search

The W-type ferrites doped with Pr3+, BaCoNiPrxFe16-xO27 (x=0-0.20), were prepared by a sol-gel method. The structure and electromagnetic properties of the samples are studied using powder X-ray diffraction, field emission scanning electron microscope, vibrating sample magnetometer and vector network analyzer. All the samples are hexagonal platelet-like W-type barium ferrite. These synthesized samples exhibit paramagnetism and strong magnetism. The saturation magnetization

Yanfei Wu; Ying Huang; Lei Niu; Yinling Zhang; Yuqing Li; Xiaoya Wang

2012-01-01

132

Magnetic and structural properties of RE doped Co-ferrite (REåNd, Eu, and Gd) nano-particles synthesized by co-precipitation  

NASA Astrophysics Data System (ADS)

Cobalt ferrite nano-particles, Co0.9RE0.1Fe2O4, with three different rare earth ions (Nd, Eu, and Gd) were prepared by the chemical co-precipitation method. X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR), and Vibrating Sample Magnetometry were carried out to study the structural and magnetic properties, respectively. The XRD results revealed that the crystal size is about 22 nm for Gd-Co ferrite, which is close to the particle sizes observed from TEM images (20 nm). The FTIR measurements between 350 and 4000 cm-1 confirmed the intrinsic cation vibrations of the spinel structure. The results showed that the RE ions increase both vibrational frequencies and bond strength. The magnetic results showed that the highest magnetic coercivity and the loop area correspond to the Gd-Co ferrite, making it suitable for hyperthermia treatment. Also, the Curie point was decreased by the RE ions and had its lowest value for Nd-Co ferrite (336 °C).

Amiri, S.; Shokrollahi, H.

2013-11-01

133

Influence of SiO2 matrix and annealing time on properties of Ni-ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel ferrite nanoparticles dispersed in SiO2 matrix have been synthesized by using sol-gel method. Influence of SiO2 concentration and annealing time on properties of nickel ferrite nanoparticles have been studied in detail in order to synthesize small (diameter around 10 nm) nickel ferrite nanoparticles with improved magnetic properties. Structural characterization includes X-ray diffraction (XRD) and transmission electron microscopy (TEM). Magnetic measurements have been done using SQUID-magnetometer. Average particle size decreases with increasing SiO2 matrix concentration, while it shows an increasing trend with increasing annealing time. The decrease of particle size at higher SiO2 concentration is due to large number of nucleation centers which finally restrict the nanoparticle growth. Saturation magnetization shows a decreasing trend with increasing SiO2 matrix concentration, while coercivity behaves oppositely and is attributed to increased number of disordered surface spins in small nanoparticles. Magnetic properties of the small nanoparticles have been improved on increasing annealing time with a corresponding increase in crystallite size. Therefore control over nanoparticle size, nanoparticle distribution, and magnetic properties could be achieved using optimum SiO2 matrix concentration and annealing time.

Nadeem, K.; Krenn, H.; Shahid, M.; Letofsky-Papst, I.

2013-05-01

134

Highly coercive cobalt ferrite nanoparticles-CuTl-1223 superconductor composites  

NASA Astrophysics Data System (ADS)

We explored the effects of highly coercive cobalt ferrite (CoFe2O4) nanoparticles addition on structural, morphological, and superconducting properties of Cu0.5Tl0.5Ba2Ca2Cu3O10-? (CuTl-1223} matrix. Series of (CoFe2O4)x/CuTl-1223 (x=0 2.0 wt%) composites samples were synthesized and were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) absorption spectroscopy, and dc-resistivity versus temperature measurements. The magnetic behavior of CoFe2O4 nanoparticles was determined by MH-loops with the help of superconducting quantum interference device (SQUID). MH-loops analysis showed that these nanoparticles exhibit high saturation magnetization (86 emu/g) and high coercivity (3350 Oe) at 50 K. The tetragonal structure of host CuTl-1223 superconducting matrix was not altered after the addition of CoFe2O4 nanoparticles, which gave us a clue that these nanoparticles had occupied the inter-granular sites (grain-boundaries) and had filled the pores. The increase of mass density with increasing content of these nanoparticles in composites can also be an evidence of filling up the voids in the matrix. The resistivity versus temperature measurements showed an increase in zero resistivity critical {Tc(0)}, which could be most probably due to improvement of weak-links by the addition of these nanoparticles. But the addition of these nanoparticles beyond an optimum level caused the agglomeration and produced additional stresses in material and suppressed the superconductivity.

Jabbar, Abdul; Qasim, Irfan; Khan, Shahid A.; Nadeem, K.; Waqee-ur-Rehman, M.; Mumtaz, M.; Zeb, F.

2015-03-01

135

Synchrotron study on load partitioning between ferrite/martensite and nanoparticles of a 9Cr ODS steel  

NASA Astrophysics Data System (ADS)

Oxide dispersion strengthened (ODS) steels exhibit exceptional radiation resistance and high-temperature creep strength when compared to traditional ferritic and ferritic/martensitic (F/M) steels. Their excellent mechanical properties result from very fine nanoparticles dispersed within the matrix. In this work, we applied a high-energy synchrotron radiation X-ray to study the deformation process of a 9Cr ODS steel. The load partitioning between the ferrite/martensite and the nanoparticles was observed during sample yielding. During plastic deformation, the nanoparticles experienced a dramatic loading process, and the internal stress on the nanoparticles increased to a maximum value of 3.7 GPa, which was much higher than the maximum applied stress (?986 MPa). After necking, the loading capacity of the nanoparticles was significantly decreased due to a debonding of the particles from the matrix, as indicated by a decline in lattice strain/internal stress. Due to the load partitioning, the ferrite/martensite slightly relaxed during early yielding, and slowly strained until failure. This study develops a better understanding of loading behavior for various phases in the ODS F/M steel.

Mo, Kun; Zhou, Zhangjian; Miao, Yinbin; Yun, Di; Tung, Hsiao-Ming; Zhang, Guangming; Chen, Weiying; Almer, Jonathan; Stubbins, James F.

2014-12-01

136

Synthesis of MPTS-modified cobalt ferrite nanoparticles and their adsorption properties in relation to Au(III).  

PubMed

Cobalt ferrite magnetic nanoparticles (Co-MNP) were prepared by a co-precipitation method and subsequently coated with (3-mercaptopropyl)trimethoxysilane (MPTS) for the extraction and recovery of Au(III) from aqueous chloride solutions. Physical characterization of the MPTS-modified particles (Co-MPTS) was performed using FT-IR, TGA, and SEM. Results from FT-IR confirmed that MPTS was present on the surface of the magnetic nanoparticles. The amount of MPTS was 0.36 mmol g(-1) of Co-MPTS, obtained by elemental analysis. SEM images revealed aggregates composed of nanocrystalline Co-MPTS particles. The extraction efficiency as a function of the pH, contact time, and initial Au(III) concentration was evaluated. The modified particles showed maximum adsorption in the pH range from 1.0 to 4.0. The adsorption behavior of Co-MPTS toward Au(III) followed a Langmuir isotherm and the maximum adsorption capacity was found to be 120.5 mg g(-1). The stability of the modified materials was improved as compared to that of bare Co-MNP. The subsequent desorption of gold could be achieved by using acidified thiourea solution; the highest gold recovery reached 85%. PMID:19647836

Kraus, Andrea; Jainae, Kunawoot; Unob, Fuangfa; Sukpirom, Nipaka

2009-10-15

137

Manganese ferrite-based nanoparticles induce ex vivo, but not in vivo, cardiovascular effects  

PubMed Central

Magnetic nanoparticles (MNPs) have been used for various biomedical applications. Importantly, manganese ferrite-based nanoparticles have useful magnetic resonance imaging characteristics and potential for hyperthermia treatment, but their effects in the cardiovascular system are poorly reported. Thus, the objectives of this study were to determine the cardiovascular effects of three different types of manganese ferrite-based magnetic nanoparticles: citrate-coated (CiMNPs); tripolyphosphate-coated (PhMNPs); and bare magnetic nanoparticles (BaMNPs). The samples were characterized by vibrating sample magnetometer, X-ray diffraction, dynamic light scattering, and transmission electron microscopy. The direct effects of the MNPs on cardiac contractility were evaluated in isolated perfused rat hearts. The CiMNPs, but not PhMNPs and BaMNPs, induced a transient decrease in the left ventricular end-systolic pressure. The PhMNPs and BaMNPs, but not CiMNPs, induced an increase in left ventricular end-diastolic pressure, which resulted in a decrease in a left ventricular end developed pressure. Indeed, PhMNPs and BaMNPs also caused a decrease in the maximal rate of left ventricular pressure rise (+dP/dt) and maximal rate of left ventricular pressure decline (?dP/dt). The three MNPs studied induced an increase in the perfusion pressure of isolated hearts. BaMNPs, but not PhMNPs or CiMNPs, induced a slight vasorelaxant effect in the isolated aortic rings. None of the MNPs were able to change heart rate or arterial blood pressure in conscious rats. In summary, although the MNPs were able to induce effects ex vivo, no significant changes were observed in vivo. Thus, given the proper dosages, these MNPs should be considered for possible therapeutic applications. PMID:25031535

Nunes, Allancer DC; Ramalho, Laylla S; Souza, Álvaro PS; Mendes, Elizabeth P; Colugnati, Diego B; Zufelato, Nícholas; Sousa, Marcelo H; Bakuzis, Andris F; Castro, Carlos H

2014-01-01

138

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles.  

PubMed

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications. PMID:21774807

Girgis, Emad; Wahsh, Mohamed Ms; Othman, Atef Gm; Bandhu, Lokeshwar; Rao, Kv

2011-01-01

139

Synthesis, magnetic and optical properties of core/shell Co1-xZnxFe2O4/SiO2 nanoparticles  

PubMed Central

The optical properties of multi-functionalized cobalt ferrite (CoFe2O4), cobalt zinc ferrite (Co0.5Zn0.5Fe2O4), and zinc ferrite (ZnFe2O4) nanoparticles have been enhanced by coating them with silica shell using a modified Stöber method. The ferrites nanoparticles were prepared by a modified citrate gel technique. These core/shell ferrites nanoparticles have been fired at temperatures: 400°C, 600°C and 800°C, respectively, for 2 h. The composition, phase, and morphology of the prepared core/shell ferrites nanoparticles were determined by X-ray diffraction and transmission electron microscopy, respectively. The diffuse reflectance and magnetic properties of the core/shell ferrites nanoparticles at room temperature were investigated using UV/VIS double-beam spectrophotometer and vibrating sample magnetometer, respectively. It was found that, by increasing the firing temperature from 400°C to 800°C, the average crystallite size of the core/shell ferrites nanoparticles increases. The cobalt ferrite nanoparticles fired at temperature 800°C; show the highest saturation magnetization while the zinc ferrite nanoparticles coated with silica shell shows the highest diffuse reflectance. On the other hand, core/shell zinc ferrite/silica nanoparticles fired at 400°C show a ferromagnetic behavior and high diffuse reflectance when compared with all the uncoated or coated ferrites nanoparticles. These characteristics of core/shell zinc ferrite/silica nanostructures make them promising candidates for magneto-optical nanodevice applications. PMID:21774807

2011-01-01

140

Magnetic nanoparticle assembly arrays prepared by hierarchical self-assembly on a patterned surface.  

PubMed

Inverted pyramid hole arrays were fabricated by photolithography and used as templates to direct the growth of colloidal nanoparticle assemblies. Cobalt ferrite nanoparticles deposit in the holes to yield high quality pyramid magnetic nanoparticle assembly arrays by carefully controlling the evaporation of the carrier fluid. Magnetic measurements indicate that the pyramid magnetic nanoparticle assembly arrays preferentially magnetize perpendicular to the substrate. PMID:25712606

Wen, Tianlong; Zhang, Dainan; Wen, Qiye; Zhang, Huaiwu; Liao, Yulong; Li, Qiang; Yang, Qinghui; Bai, Feiming; Zhong, Zhiyong

2015-03-01

141

Size effect on the static and dynamic magnetic properties of W-type barium ferrite composites: From microparticles to nanoparticles  

Microsoft Academic Search

The static, dynamic, and attenuation properties of BaCoZnFe16O27 barium ferrites and their composites have been studied using microparticles and nanoparticles. The results showed that BaCoZnFe16O27 microparticles have larger saturation magnetization Ms and smaller coercivity Hc than do nanoparticles. The composites with microparticles have significantly larger real and imaginary permeabilities mu0' and mumax'' due to their multidomain structures, but low resonance

Z. W. Li; G. Q. Lin; Linfeng Chen; Y. P. Wu; C. K. Ong

2005-01-01

142

Size effect on the static and dynamic magnetic properties of W-type barium ferrite composites: From microparticles to nanoparticles  

Microsoft Academic Search

The static, dynamic, and attenuation properties of BaCoZnFe16O27 barium ferrites and their composites have been studied using microparticles and nanoparticles. The results showed that BaCoZnFe16O27 microparticles have larger saturation magnetization Ms and smaller coercivity Hc than do nanoparticles. The composites with microparticles have significantly larger real and imaginary permeabilities ?0? and ?max? due to their multidomain structures, but low resonance

Z. W. Li; G. Q. Lin; Linfeng Chen; Y. P. Wu; C. K. Ong

2005-01-01

143

Synthesis of nickel–zinc ferrite magnetic nanoparticle and dye degradation using photocatalytic ozonation  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? Nickel–zinc ferrite magnetic nanoparticle (NZFMN) was synthesized and characterized. ? Dye degradation by photocatalytic ozonation using NZFMN was studied. ? Formate, acetate and oxalate were detected as dominant dye degradation aliphatic intermediates. ? Nitrate, sulfate and chloride ions were detected as mineralization products of dyes. ? NZFMN was an effective magnetic nanocatalyst to degrade dyes. -- Abstract: In this paper, nickel–zinc ferrite magnetic nanoparticle (NZFMN) was synthesized and its dye degradation ability using photocatalytic ozonation was investigated. The NZFMN was characterized by X-ray diffraction (XRD), scanning electron microscopic (SEM), Fourier transforms infrared (FTIR) and alternative gradient force magnetometer (AGFM). Reactive Red 198 (RR198) and Direct Green 6 (DG6) were used as dye models. UV–vis and ion chromatography (IC) analyses were employed to study dye degradation. The effects of operational parameters on decolorization such as NZFMN dosage, dye concentration, salt and pH were studied. RR198 and DG6 were completely decolorized (100%) by photocatalytic ozonation using NZFMN. Formate, acetate and oxalate anions were detected as dominant aliphatic intermediates. Nitrate, sulfate and chloride ions were detected as mineralization products of dyes. Results showed that the photocatalytic ozonation using NZFMN was a very effective method for dye degradation.

Mahmoodi, Niyaz Mohammad, E-mail: mahmoodi@icrc.ac.ir [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Bashiri, Marziyeh; Moeen, Shirin Jebeli [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)] [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)

2012-12-15

144

Method for preparing spherical ferrite beads and use thereof  

DOEpatents

The invention allows the fabrication of small, dense, highly polished spherical beads of hexagonal ferrites with selected compositions for use in nonreciprocal microwave and mm-wave devices as well as in microwave absorbent or reflective coatings, composites, and the like. A porous, generally spherical bead of hydrous iron oxide is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead is washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) under conditions of elevated temperature and pressure to convert the bead into a mixed hydrous iron-alkaline earth oxide while retaining the generally spherical shape. This mixed oxide bead is then washed, dried, and calcined to produce the desired (BaFe.sub.12 O.sub.19 or SrFe.sub.12 O.sub.19) crystal structure. The calcined bead is then sintered to form a dense bead of the BaFe.sub.12 O.sub.19 and SrFe.sub.12 O.sub.19 phase suitable for polishing and incorporation into various microwave devices and components.

Lauf, Robert J. (Oak Ridge, TN); Anderson, Kimberly K. (Knoxville, TN); Montgomery, Frederick C. (Oak Ridge, TN); Collins, Jack L. (Knoxville, TN)

2002-01-01

145

Preparation of medical magnetic nanobeads with ferrite particles encapsulated in a polyglycidyl methacrylate (GMA) for bioscreening  

NASA Astrophysics Data System (ADS)

Ferrite nanoparticles (an intermediate between Fe3O4 and ?-Fe2O3), ˜7nm in diameter, were embedded in beads of a mixed polymer of styrene (St) and glycidyl methacrylate (GMA) by emulsifier-free emulsion polymerization method. The beads were coated with GMA by a seeded polymerization method in order to suppress nonspecific protein binding on the surfaces; GMA exhibits very low nonspecific protein binding, which is required for carriers used for bioscreening. The beads have diameters of 180±50nm and saturation magnetizations of 28emu /g, exceeding commercially available polymer-coated beads of micron size having a weaker saturation magnetization (˜12emu/g).

Nishibiraki, H.; Kuroda, C. S.; Maeda, M.; Matsushita, N.; Abe, M.; Handa, H.

2005-05-01

146

Nanosized barium ferrite powders prepared by spray pyrolysis from citric acid solution  

Microsoft Academic Search

Highly crystalline nanosized barium ferrite (BaFe12O19) powders were prepared by spray pyrolysis from a spray solution containing a high concentration of the metal components. The precursor powders obtained from the spray solution containing citric acid were amorphous with a porous and hollow structure. Purely crystalline and fine BaFe12O19 powders were obtained after post-treatment between 700 and 1000°C and subsequent mechanical

Min Ha Kim; Dae Soo Jung; Yun Chan Kang; Jeong Hoo Choi

2009-01-01

147

Optimization of the glycine-metal nitrate combustion method for preparing barium ferrite (abstract)  

Microsoft Academic Search

A combustion-synthesis method1 has been adapted2 for the preparation of barium ferrite. In this method, stoichiometric amounts of metal-nitrate solutions are mixed and glycine (aminoacetic acid) is added at specific glycine\\/metal-nitrate ratios. The resulting solution is then heated until autoignition (combustion). The combustion products for several G\\/N ratios have been analyzed by XRD, Mo¨ssbauer spectroscopy, and EDS; they consist of

Manson L. Wade; David G. Agresti; Jenny O. Hai; Robin Griffin; Yang-Ki Hong

1993-01-01

148

Synthesis of cobalt ferrite core/metallic shell nanoparticles for the development of a specific PNA/DNA biosensor.  

PubMed

Controlled synthesis of cobalt ferrite superparamagnetic nanoparticles covered with a gold shell has been achieved by an affinity and trap strategy. Magnetic nanoparticles are functionalized with a mixture of amino and thiol groups that facilitate the electrostatic attraction and further chemisorption of gold nanoparticles, respectively. Using these nanoparticles as seeds, a complete coating shell is achieved by gold salt-iterative reduction leading to monodisperse water-soluble gold-covered magnetic nanoparticles, with an average diameter ranging from 21 to 29 nm. These constitute a versatile platform for immobilization of biomolecules via thiol chemistry, which is exemplified by the immobilization of peptide nucleic acid (PNA) oligomers that specifically hybridize with complementary DNA molecules in solution. Hybridation with DNA probes has been measured using Rhodamine 6G fluorescence marker and the detection of a single nucleotide mutation has been achieved. These results suggest the PNA-nanoparticles application as a biosensor for DNA genotyping avoiding commonly time-consuming procedures employed. PMID:18329659

Pita, Marcos; Abad, José María; Vaz-Dominguez, Cristina; Briones, Carlos; Mateo-Martí, Eva; Martín-Gago, José Angel; Morales, Maria del Puerto; Fernández, Víctor M

2008-05-15

149

Anatase TiO 2 nanolayer coating on cobalt ferrite nanoparticles for magnetic photocatalyst  

Microsoft Academic Search

TiO2\\/CoFe2O4 composite nanoparticles with a core–shell structure have been obtained. The core CoFe2O4 nanoparticles were synthesized via co-precipitation method, and the shell TiO2 nanocrystals were derived via sol–gel technology followed by heat-treatment at 450 °C. The morphology and the crystalline structure of composite nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction, respectively. The as-prepared composite particles can

Wuyou Fu; Haibin Yang; Minghua Li; Minghui Li; Nan Yang; Guangtian Zou

2005-01-01

150

Synthesis and characterization of CoFe2O4 ferrite nanoparticles obtained by an electrochemical method.  

PubMed

Uniform size cobalt ferrite nanoparticles have been synthesized in one step using an electrochemical technique. Synthesis parameters such as the current density, temperature and stirring were optimized to produce pure cobalt ferrite. The nanoparticles have been investigated by means of magnetic measurements, Mössbauer spectroscopy, x-ray powder diffraction and transmission electron microscopy. The average size of the electrosynthesized samples was controlled by the synthesis parameters and this showed a rather narrow size distribution. The x-ray analysis shows that the CoFe(2)O(4) obtained presents a totally inverse spinel structure. The magnetic properties of the stoichiometric nanoparticles show ferromagnetic behavior at room temperature with a coercivity up to 6386 Oe and a saturation magnetization of 85 emu g(-1). PMID:22894928

Mazarío, E; Herrasti, P; Morales, M P; Menéndez, N

2012-09-01

151

Advances in the preparation of novel functionalized nanoparticles for bioimaging  

Microsoft Academic Search

The EC BONSAI Project intends to develop multifunctional nanoparticles with tailored optical and\\/or magnetic properties for visualizing complex cellular structures (in tissues and organs), receptors, tumor cells and masses. In this framework, here we will report on recent advances on the preparation of luminescent silicon nanoparticles, magnetic iron oxide nanoparticles and Au nanorods for bio-imaging applications.

R. Alexandrescu; V. Bouzas; N. Carmona; M. Chanana; R. Costo; F. Dumitrache; F. Fabbri; M. Falconieri; M. A. Garcia; P. Gasco; W. Gonzalez; N. Herlin; V. Maurice; F. Huisken; J. M. Idee; V. Loschenov; G. Mattei; G. Miserocchi; M. P. Morales; I. Morjan; Y. Nie; M. Port; V. Pustovoy; G. Riccio; I. Rivolta; A. Ryabova; C. Robic; G. Sancini; O. Sublemontier; E. Trave; S. Veintemillas-Verdaguer; N. Vivenza; D. Wang; H. Xu; E. Borsella

2009-01-01

152

Microstructure and MO enhancement in Ni-substituted Ba ferrite films prepared by sputtering (abstract)  

NASA Astrophysics Data System (ADS)

Sputtered Ba ferrite films are promising media for magneto-optical (MO) recording because they have strong perpendicular magnetic anisotropy. However, MO activity of the Ba ferrites is low, which makes the feasibility as a practical medium poor. The MO activity is reported to be prominently enhanced by specific ions such as Bi3+, Co2+, and light rare earth ions in garnet ferrites, while, in Ba ferrites, the MO enhancement ions except Co2+ have not yet been known. We have recently found that Ni2+ substitution also enhances Faraday rotation in the visible region around h?=2.5 eV. In this paper we describe MO properties as well as microstructures of Ba1-xMxFe12-xNixO19 (M=La, Pr, x=0, 0.3, 0.6) films prepared by rf sputtering. The films were deposited on Gd3Ga5O12 (GGG) single crystal substrates at substrate temperature (Ts) of 400-600 °C by the conventional rf diode sputtering. When Ts?550 °C for the incident rf power over 19 W/cm2, the films in situ crystallized in Ba-ferrite single phase. They had c-crystal axis well oriented normal to the film plane. The SEM and TEM observations revealed that the grain size in the films increases from several nm to ˜300 nm with increasing the incident power. The films with larger grains showed higher saturation magnetization and lower coercivity. Faraday rotation of the films was clearly enhanced in the visible around 2.5 eV with increasing Ni2+ substitution, though they showed rather complicated spectral structure inherent to the Ba ferrites. The enhancement factor of specific Faraday rotation at 2.5 eV was as large as 2×104 deg/x, independent of the kind of the rare earth ion substituted for Ba2+ for charge compensation. This implies that the substitution of the rare earth ion itself enhances no Faraday rotation in Ba ferrites. Thus, the MO enhancement around 2.5 eV may be attributed to the octahedrally coordinated Ni2+.

Gomi, M.; Shimai, K.; Cho, J.; Abe, M.

1993-05-01

153

Synthesis and characterization of hard magnetic composites—Hollow microsphere\\/titania\\/barium ferrite  

Microsoft Academic Search

Hard magnetic composites—hollow microsphere (core)\\/titania (intermediate layer)\\/barium ferrite (magnetic shell) (M\\/T\\/B) were prepared by wet-chemical method. Barium ferrite nanoparticles were directly coated on the rutile titania-coated hollow microsphere forming light hard magnetic composites using sol–gel technique. The prepared composites were characterized with FESEM, EDS, XRD and vibrating sample magnetometry. The composites are composed of barium ferrite, hematite, titania and mullite.

Guohong Mu; Xifeng Pan; Na Chen; Chihuan He; Mingyuan Gu

2008-01-01

154

Synergetic effect of size and morphology of cobalt ferrite nanoparticles on proton relaxivity.  

PubMed

Cobalt ferrite nanoparticles with average sizes of 14, 9 and 6 nm were synthesised by the chemical co-precipitation technique. Average particle sizes were varied by changing the chitosan surfactant to precursor molar ratio in the reaction mixture. Transmission electron microscopy images revealed a faceted and irregular morphology for the as-synthesised nanoparticles. Magnetic measurements revealed a ferromagnetic nature for the 14 and 9 nm particles and a superparamagnetic nature for the 6 nm particles. An increase in saturation magnetisation with increasing particle size was noted. Relaxivity measurements were carried out to determine T2 value as a function of particle size using nuclear magnetic resonance measurements. The relaxivity coefficient increased with decrease in particle size and decrease in the saturation magnetisation value. The observed trend in the change of relaxivity value with particle size was attributed to the faceted nature of as-synthesised nanoparticles. Faceted morphology results in the creation of high gradient of magnetic field in the regions adjacent to the facet edges increasing the relaxivity value. The effect of edges in increasing the relaxivity value increases with decrease in the particle size because of an increase in the total number of edges per particle dispersion. PMID:25429495

N, Venkatesha; Srivastava, Chandan; Hegde, Veena

2014-12-01

155

Effect of particle size on structural, magnetic and dielectric properties of manganese substituted nickel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Mn substituted NiFe2O4 ferrite nanoparticles (Mn-NiFe2O4) were synthesized by the auto-combustion method. Their actions were carried out at different fuel ratios (50%, 75% and 100%). The nanoparticles have been investigated by X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. The average crystallite size of the synthesized and annealed samples was between 25 and 75 nm, which were found to be dependent on both fuel ratio and annealing temperatures. However, lattice parameters, interplanar spacing and grain size were controlled by varying the fuel ratio. Magnetic characterizations of the nanoparticles were carried out using a vibrating sample magnetometer at room temperature. The saturation magnetization was computed and found to lie between 6 emu/g and 57 emu/g depending on the particle size of the studied sample. The coercivity was found to exhibit non-monotonic behavior with the particle size. Such behavior can be accounted for by the combination between surface anisotropy and thermal energies. The value of dielectric constant and dielectric loss was found to exhibit almost linear dependence on the particle size.

Kumar, E. Ranjith; Kamzin, Aleksandr S.

2015-03-01

156

Preparation and characterization of manganese ferrite-based magnetic liposomes for hyperthermia treatment of cancer  

NASA Astrophysics Data System (ADS)

Comparative evaluation of two different methods of magnetic liposomes preparation, namely thin film hydration (TFH) and double emulsion (DE) with different molar ratios of egg-phosphatidyl choline (egg-PC) and cholesterol using lauric acid coated manganese ferrite-based aqueous magnetic fluid, is reported. TFH was found to be a better method of encapsulation and TFH 2:1 (egg-PC: cholesterol) magnetic liposomes showed the highest encapsulation efficiency and comparable heating ability to that of magnetic fluids. Stealth TFH 2:1 magnetic liposomes containing DSPE-PEG 2000 were three-fold more cytocompatible as compared to the magnetic fluid. Stealth TFH 2:1 manganese ferrite-based magnetic liposomes might be useful for hyperthermia treatment of cancer.

Pradhan, Pallab; Giri, Jyotsnendu; Banerjee, Rinti; Bellare, Jayesh; Bahadur, Dhirendra

2007-04-01

157

Preparation and Characterization of Amino-Coated Maghemite Nanoparticles  

Microsoft Academic Search

The ferrous salt and ferric salt were used as raw materials to prepare magnetite (Fe3O4) nanoparticles as precursors, and then maghemite (?-Fe2O3) nanoparticles were obtained from the precursors via high temperature pyrolysis for further oxidation, and corresponding amino-coated maghemite nanoparticles are also obtained via surface modification of 3-aminopropyltriethyloxy silane (APTES). The properties and structure of nanoparticles are characterized by transmission

Lei Zeng; Rong Hu; Zhaohui Wu; Quanguo He

2010-01-01

158

Solar photocatalytic degradation of RB5 by ferrite bismuth nanoparticles synthesized via ultrasound.  

PubMed

In this paper, the photocatalytic degradation of Reactive Black 5 (RB5) was investigated with ferrite bismuth synthesized via ultrasound under direct sunlight irradiation. The intensity of absorption peaks of RB5 gradually decreased by increasing the irradiation time and finally vanished in 50 min in acidic medium. The formation of new intermediate was observed in basic medium. The relative concentration of RB5 in solution and on the surface of ferrite bismuth (BiFeO3) nanoparticles was considered during the experiment in acidic and basic media. The effects of various parameters such as amount of catalyst, concentration of dye, and pH of the solution have been studied on the dye degradation. The adsorption isotherm and the kinetic of photocatalytic degradation of RB5 were investigated. The adsorption constants in the dark and in the presence of sunlight irradiation were compared. The photocatalytic degradation mechanism of RB5 has been evaluated through the addition of some scavengers to the solution. In addition, the stability and reusability of the catalyst were examined in this work. PMID:23466007

Soltani, T; Entezari, M H

2013-09-01

159

Fabrication of a glucose biosensor based on citric acid assisted cobalt ferrite magnetic nanoparticles.  

PubMed

A novel and practical glucose biosensor was fabricated with immobilization of Glucose oxidase (GOx) enzyme on the surface of citric acid (CA) assisted cobalt ferrite (CF) magnetic nanoparticles (MNPs). This innovative sensor was constructed with glassy carbon electrode which is represented as (GOx)/CA-CF/(GCE). An explicit high negative zeta potential value (-22.4 mV at pH 7.0) was observed on the surface of CA-CF MNPs. Our sensor works on the principle of detection of H2O2 which is produced by the enzymatic oxidation of glucose to gluconic acid. This sensor has tremendous potential for application in glucose biosensing due to the higher sensitivity 2.5 microA/cm2-mM and substantial increment of the anodic peak current from 0.2 microA to 10.5 microA. PMID:22962799

Krishna, Rahul; Titus, Elby; Chandra, Sudeshna; Bardhan, Neel Kanth; Krishna, Rohit; Bahadur, Dhirendra; Gracio, José

2012-08-01

160

Cellular distribution and degradation of cobalt ferrite nanoparticles in Balb/3T3 mouse fibroblasts.  

PubMed

The effect of the concentration of cobalt ferrite (CoFe(2)O(4)) nanoparticles (NPs) on their intracellular location and distribution has been explored by synchrotron radiation X-ray and fluorescence microscopy (SR-XRF) monitoring the evolution of NPs elemental composition as well. In cells exposed to low concentrations of CoFe(2)O(4) NPs, the NPs preferentially segregate in the perinuclear region preserving their initial chemical content. At concentrations exceeding 500 ?M the XRF spectra indicate the presence of Co and Fe also in the nuclear region, accompanied by sensible changes in the cellular morphology. The increase of the Co/Fe ratio measured in the nuclear compartment indicates that above certain concentrations the CoFe(2)O(4) NPs intracellular distribution could be accompanied by biodegradation resulting in Co accumulation in the nucleus. PMID:21925252

Marmorato, Patrick; Ceccone, Giacomo; Gianoncelli, Alessandra; Pascolo, Lorella; Ponti, Jessica; Rossi, François; Salomé, Murielle; Kaulich, Burkhard; Kiskinova, Maya

2011-11-30

161

Preparation and Characterization of Calcium Carbonate Nanoparticles  

NASA Astrophysics Data System (ADS)

Taking calcium supplements can reduce the risk of developing osteoporosis, but they are not readily absorbed in the gastrointestinal tract. Nanotechnology is expected to resolve this problem. In this study, we prepared and characterized calcium carbonate nanoparticle to improve the solubility by using bottom-up method. The experiment was done by titrating calcium chloride with sodium carbonate with the addition of polyvinylpyrrolidone (PVP) as stabilizer, using ultra-turrax. Various concentrations of calcium chloride and sodium carbonate as well as various speed of stirring were used to prepare the calcium carbonate nanoparticles. Evaluations studied were including particle size, polydispersity index (PI) and zeta potential with particle analyzer, surface morphology with scanning electron microscope, and saturated solubility. In addition, to test the ability of PVP to prevent particles growth, short stability study was performed by storing nano CaCO3 suspension at room temperature for 2 weeks. Results show that using 8000 rpm speed of stirring, the particle size tends to be bigger with the range of 500-600 nm (PI between 0.2-0.4) whereas with stirring speed of 4000 rpm, the particle size tends to be smaller with 300-400 nm (PI between 0.2-0.4). Stirring speed of 6000 rpm produced particle size within the range of 400-500 nm (PI between 0.2-0.4). SEM photograph shows that particles are monodisperse confirming that particles were physically stable without any agglomeration within 2 weeks storage. Taken together, nano CaCO3 is successfully prepared by bottom-up method and PVP is a good stabilizer to prevent the particle growth.

Hassim, Aqilah; Rachmawati, Heni

2010-10-01

162

Study of NiCuZn ferrite powders and films prepared by sol—gel method  

NASA Astrophysics Data System (ADS)

This paper reports that a series of NiCuZn ferrite powders and films are prepared by using sol—gel method. The effects of raw material composition and the calcinate temperature on magnetic properties of them are investigated. The NiCuZn ferrite powders are prepared by the self-propagating high-temperature synthesis method and subsequently heated at 700 °C~1000 °C. The results show that NiCuZn ferrite powders with single spinel phase can be formed after heat-treating at 750 °C. Powders obtained from Ni0.4Cu0.2Zn0.4Fe1.9O4 gel have better magnetic properties than those from gels with other composition. After heat-treating at 900 °C for 3 h, coercivity Hc and saturation magnetization Ms are 9.7 Oe (1 Oe = 80 A/m) and 72.4 emu/g, respectively. Different from the powders, NiCuZn films produced on Si (100) from the Ni0.4Cu0.2Zn0.4Fe2O4 gel formed at room temperature possess high properties. When heat-treating condition is around 600 °C for 6 min, samples with low Hc and high Ms will be obtained. The minimal Hc is 16.7 Oe and Ms is about 300 emu/cm3. In comparison with the films prepared through long-time heat treating, the films prepared through short heat-treating time exhibits better soft magnetic properties.

Gao, Liang-Qiu; Yu, Guo-Jian; Wang, Ying; Wei, Fu-Lin

2011-02-01

163

Preparation and magnetic properties of epitaxial barium ferrite thin films on sapphire with in-plane, uniaxial anisotropy  

Microsoft Academic Search

For the first time, epitaxial barium-ferrite thin films, predominantly of the magnetoplumbite structure, with an easy axis of magnetization in-plane have been prepared on single-crystal sapphire substrates by reactive sputtering and post-deposition annealing. Lattice images by high resolution transmission electron microscopy reveal the probable origin of the magnetic anisotropy to be epitaxy between the Ba-ferrite and sapphire, causing the c-axis

T. L. Hylton; M. A. Parker; J. K. Howard

1992-01-01

164

Solvothermal synthesis of cobalt ferrite nanoparticles loaded on multiwalled carbon nanotubes for magnetic resonance imaging and drug delivery.  

PubMed

Multiwalled carbon nanotube (MWCNT)/cobalt ferrite (CoFe(2)O(4)) magnetic hybrids were synthesized by a solvothermal method. The reaction temperature significantly affected the structure of the resultant MWCNT/CoFe(2)O(4) hybrids, which varied from 6nm CoFe(2)O(4) nanoparticles uniformly coated on the nanotubes at 180°C to agglomerated CoFe(2)O(4) spherical particles threaded by MWCNTs and forming necklace-like nanostructures at 240°C. Based on the superparamagnetic property at room temperature and high hydrophilicity, the MWCNT/CoFe(2)O(4) hybrids prepared at 180°C (MWCNT/CoFe(2)O(4)-180) were further investigated for biomedical applications, which showed a high T(2) relaxivity of 152.8 Fe mM(-1)s(-1) in aqueous solutions, a significant negative contrast enhancement effect on cancer cells and, more importantly, low cytotoxicity and negligible hemolytic activity. The anticancer drug doxorubicin (DOX) can be loaded onto the hybrids and subsequently released in a sustained and pH-responsive way. The DOX-loaded hybrids exhibited notable cytotoxicity to HeLa cancer cells due to the intracellular release of DOX. These results suggest that MWCNT/CoFe(2)O(4)-180 hybrids may be used as both effective magnetic resonance imaging contrast agents and anticancer drug delivery systems for simultaneous cancer diagnosis and chemotherapy. PMID:21664499

Wu, Huixia; Liu, Gang; Wang, Xue; Zhang, Jiamin; Chen, Yu; Shi, Jianlin; Yang, Hong; Hu, He; Yang, Shiping

2011-09-01

165

Plasma-assisted catalytic dry reforming of methane: Highly catalytic performance of nickel ferrite nanoparticles embedded in silica  

NASA Astrophysics Data System (ADS)

Spinel nickel ferrite nanoparticles (NiFe2O4 NPs) embedded in silica (NiFe2O4#SiO2) was prepared to enhance the reaction performance of the dry reforming of methane in a coaxial dielectric barrier discharge reactor. NiFe2O4 NPs of around 10 nm were effectively embedded in porous SiO2 NPs (?100 nm in diameter). Compared to the supported Ni-based catalysts (Ni/?-Al2O3, Ni-Fe/?-Al2O3, Ni-Fe/SiO2, and NiFe2O4), the NiFe2O4#SiO2 catalyst placed at the discharge zone exhibited excellent catalytic performance and high resistance to carbon formation during dry reforming under ambient conditions without the involvement of extra heat. The synergetic effect between the non-thermal plasma and the NiFe2O4#SiO2 catalyst favored the conversion of CH4 and CO2 into syngas. The results indicated that the special structure of the as-synthesized NiFe2O4#SiO2 catalyst was capable of restraining the aggregation of Ni-Fe alloy and suppressing the carbon formation in the reforming process.

Zheng, Xiaogang; Tan, Shiyu; Dong, Lichun; Li, Shaobo; Chen, Hongmei

2015-01-01

166

A comparison between the structural, magnetic and surface properties of cobalt ferrites prepared by wet and ceramic methods  

Microsoft Academic Search

Magnetic, structural and surface properties of cobal ferrites prepared by wet methods, which exhibit a single phase range notably wider than that foreseen by phase diagram, were compared with those of corresponding samples prepared by the ceramic method. Experimental results indicate that surface properties do not differs substantially, while bulk properties do.

N. Burriesci; F. Garbassi; S. Pizzini

1978-01-01

167

Incorporation of cobalt-ferrite nanoparticles into a conducting polymer in aqueous micellar medium: strategy to get photocatalytic composites.  

PubMed

In this study an easy strategy for conducting polymer based nanocomposite formation is presented through the deposition of cobalt-ferrite (CoFe(2)O(4)) containing poly(3,4-ethylenedioxythiophene) (PEDOT) thin layers. The electrochemical polymerization has been performed galvanostatically in an aqueous micellar medium in the presence of the nanoparticles and the surface active Triton X-100. The nanoparticles have been characterized by Transmission electron microscopy (TEM), the thin layers has been studied by applying Scanning electron microscopy (SEM), and X-ray diffraction (XRD), and the basic electrochemical properties have been also determined. Moreover, electrocatalytic activity of the composite was demonstrated in the electrooxidation reaction of dopamine (DA). The enhanced sensitivity - related to the cobalt-ferrite content - and the experienced photocatalyitic activity are promising for future application. PMID:25125121

Endr?di, Balázs; Hursán, Dorottya; Petrilla, Liliána; Bencsik, Gábor; Visy, Csaba; Chams, Amani; Maslah, Nabiha; Perruchot, Christian; Jouini, Mohamed

2014-01-01

168

Millimeter-wave magneto-dielectric effects in self-assembled ferrite-ferroelectric core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

The magneto-dielectric effect (MDE) involves studies on the influence of an applied magnetic field on the dielectric constant of a material. MDEs in self-assembled core-shell nanoparticles of nickel ferrite and barium titanate have been investigated in the millimeter wave frequencies. The core-shell nanocomposites were synthesized by coating 15 nm nickel ferrite and 100 nm barium titanate nanoparticles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst forming heterogeneous nanocomposites. Studies on MDE in as-assembled particles have been carried out by measurements of the relative permittivity as a function of frequency f under an applied static magnetic field H over 16-24 GHz. Measurements show an H-induced decrease in permittivity by 0.8% for H = 4 kOe and is much stronger than MDE in single phase multiferroics. A model for the high frequency MDE has been discussed here.

Srinivasan, G.; Popov, M.; Sreenivasulu, G.; Petrov, V. M.; Chavez, F.

2015-05-01

169

Magnetic nanoparticle assembly arrays prepared by hierarchical self-assembly on a patterned surface  

NASA Astrophysics Data System (ADS)

Inverted pyramid hole arrays were fabricated by photolithography and used as templates to direct the growth of colloidal nanoparticle assemblies. Cobalt ferrite nanoparticles deposit in the holes to yield high quality pyramid magnetic nanoparticle assembly arrays by carefully controlling the evaporation of the carrier fluid. Magnetic measurements indicate that the pyramid magnetic nanoparticle assembly arrays preferentially magnetize perpendicular to the substrate.Inverted pyramid hole arrays were fabricated by photolithography and used as templates to direct the growth of colloidal nanoparticle assemblies. Cobalt ferrite nanoparticles deposit in the holes to yield high quality pyramid magnetic nanoparticle assembly arrays by carefully controlling the evaporation of the carrier fluid. Magnetic measurements indicate that the pyramid magnetic nanoparticle assembly arrays preferentially magnetize perpendicular to the substrate. Electronic supplementary information (ESI) available: Experimental methods and characterization, a TEM image of cobalt ferrite nanoparticles, SEM images of cobalt ferrite nanoparticle crystals on IPHA formed by fast evaporation and slow pulling out from nanoparticle solution by using a dip coater, a SEM image of a partially filled inverted pyramid hole. See DOI: 10.1039/c4nr07489k

Wen, Tianlong; Zhang, Dainan; Wen, Qiye; Zhang, Huaiwu; Liao, Yulong; Li, Qiang; Yang, Qinghui; Bai, Feiming; Zhong, Zhiyong

2015-03-01

170

Preparation of drug nanoparticles by emulsion evaporation method  

NASA Astrophysics Data System (ADS)

Polymeric drug nanoparticles were prepared by emulsion solvent evaporation method. In this study, prepared the polymeric drug nanoparticles consist of ketoprofen and Eudragit E 100. The morphology structure was investigated by scanning electron microscopy (SEM). The interactions between the drug and polymer were investigated by Fourier transform infrared spectroscopy (FTIR). The size distribution was measured by means of Dynamic Light Scattering. The nanoparticles have an average size of about 150 nm. The incorporation ability of drugs in the polymeric nanoparticles depended on the integration between polymer and drug as well as the glass transition temperature of the polymer.

Hoa, Le Thi Mai; Chi, Nguyen Tai; Triet, Nguyen Minh; Thanh Nhan, Le Ngoc; Mau Chien, Dang

2009-09-01

171

Structural and magnetic properties of Zn-substituted cobalt ferrites prepared by co-precipitation method.  

PubMed

Zn substituted cobalt ferrite spinels with the general formula Zn(x)Co(1-x)Fe(2)O(4) (with x varying from 0 to 0.5) were synthesized by a co-precipitation method and calcined at 500 °C and 800 °C. It was found that Zn substitution has a big effect in decreasing the Curie temperature (T(c)), from around 440 °C for the undoped sample to ~180 °C with x = 0.5. However, these values were also strongly affected by the pre-calcination temperature of the samples, thus T(C) shifts from ~275 °C for the x = 0.3 sample to ~296 °C after calcination at 500 °C and 800 °C respectively. These effects are due to facilitation of demagnetisation by substitution of the non-magnetic Zn ions and by production of very small nanoparticles. The latter are removed by higher temperature calcinations and so T(C) increases. PMID:21952718

Yaseneva, Polina; Bowker, Michael; Hutchings, Graham

2011-11-01

172

Preparation of medical magnetic nanobeads with ferrite particles encapsulated in a polyglycidyl methacrylate (GMA) for bioscreening  

SciTech Connect

Ferrite nanoparticles (an intermediate between Fe{sub 3}O{sub 4} and {gamma}-Fe{sub 2}O{sub 3}), {approx}7 nm in diameter, were embedded in beads of a mixed polymer of styrene (St) and glycidyl methacrylate (GMA) by emulsifier-free emulsion polymerization method. The beads were coated with GMA by a seeded polymerization method in order to suppress nonspecific protein binding on the surfaces; GMA exhibits very low nonspecific protein binding, which is required for carriers used for bioscreening. The beads have diameters of 180{+-}50 nm and saturation magnetizations of 28 emu/g, exceeding commercially available polymer-coated beads of micron size having a weaker saturation magnetization ({approx}12 emu/g)

Nishibiraki, H.; Kuroda, C.S.; Maeda, M.; Matsushita, N.; Abe, M.; Handa, H. [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552 (Japan); Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho Midori-ku, Yokohama 226-8503 (Japan)

2005-05-15

173

Structural, electrical, magnetic and dielectric properties of rare-earth substituted cobalt ferrites nanoparticles synthesized by the co-precipitation method  

NASA Astrophysics Data System (ADS)

Pure nanoparticles of the rare-earth substituted cobalt ferrites CoRExFe2-xO4 (where RE=Nd, Sm and Gd and x=0.1 and 0.2) were prepared by the chemical co-precipitation method. X-ray diffraction, Transmission electron microscopy (TEM), d.c. electrical conductivity, Magnetic hysteresis and Thermal analysis are utilized in order to study the effect of variation in the rare-earth substitution and its impact on particle size, magnetic properties like MS, HC and Curie temperature. The phase identification of the materials by X-ray diffraction reveals the single-phase nature of the materials. The lattice parameter increased with rare-earth content for x?0.2. The Transmission electron micrographs of Nd-, Sm- and Gd-substituted CoFe2O4 exhibit the particle size 36.1 to 67.8 nm ranges. The data of temperature variation of the direct current electrical conductivity showed definite breaks, which corresponds to ferrimagnetic to paramagnetic transitions. The thermoelectric power for all compound are positive over the whole range of temperature. The dielectric constant decreases with frequency and rare-earth content for the prepared samples. The magnetic properties of rare-earth substituted cobalt ferrites showed a definite hysteresis loop at room temperature. The reduction of coercive force, saturation magnetization, ratio MR/MS and magnetic moments may be due to dilution of the magnetic interaction.

Nikumbh, A. K.; Pawar, R. A.; Nighot, D. V.; Gugale, G. S.; Sangale, M. D.; Khanvilkar, M. B.; Nagawade, A. V.

2014-04-01

174

Preparation and characterization of spinel nickel ferrite obtained by the soft mechanochemically assisted synthesis  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? NiFe{sub 2}O{sub 4} has been prepared by a soft mechanochemical route from mixture of powders. ? The spinel phase formation was completed after 25 h. ? The synthesized ferrites have a crystallite size of about 25 and 15 nm. ? Based on Raman research is observed five first-order Raman active modes. ? We were able to estimate the degree of inversion at most 0.82 and 0.66. -- Abstract: Nickel ferrite, NiFe{sub 2}O{sub 4} has been prepared by a soft mechanochemical route from mixture of (1) Ni(OH){sub 2} and ?-Fe{sub 2}O{sub 3} and (2) Ni(OH){sub 2} and Fe(OH){sub 3} powders in a planetary ball mill for varying duration. Soft mechanochemical reaction leading to formation of the NiFe{sub 2}O{sub 4} spinel phase was followed by X-ray diffraction, Raman and infrared spectroscopy, TGA, scanning and transmission microscopy. The spinel phase formation was first observed after 4 h of milling and its formation was completed after 25 h in the both cases. The synthesized NiFe{sub 2}O{sub 4} ferrite has a nanocrystalline structure with a crystallite size of about 20 and 10 nm respectively for the cases (1) and (2). The final grain size in the system (1) is about twice as large as that in the system (2), what is a consequence of different reaction paths in these two processing routes. There are five Raman and four IR active modes. Mössbauer spectroscopy studies implied on the possible cation distribution between the tetrahedral and octahedral sites in formed NiFe{sub 2}O{sub 4} spinel structure. We were able to estimate the degree of inversion at most 0.82 in the case (1) and 0.66 in the case (2).

Lazarevi?, Z.Ž., E-mail: lzorica@yahoo.com [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Jovaleki?, ?. [The Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade (Serbia)] [The Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade (Serbia); Re?nik, A. [Department for Nanostructured Materials, Jožef Stefan Institute, Ljubljana (Slovenia)] [Department for Nanostructured Materials, Jožef Stefan Institute, Ljubljana (Slovenia); Ivanovski, V.N. [Institute of Nuclear Sciences Vin?a, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)] [Institute of Nuclear Sciences Vin?a, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Milutinovi?, A.; Rom?evi?, M. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia)] [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Pavlovi?, M.B. [Faculty of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, Belgrade (Serbia)] [Faculty of Electrical Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, Belgrade (Serbia); Ceki?, B. [Institute of Nuclear Sciences Vin?a, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)] [Institute of Nuclear Sciences Vin?a, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Rom?evi?, N.Ž. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia)] [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia)

2013-02-15

175

Preparation and characteristics of Ni-ferrite powders obtained in the presence of fused salts  

Microsoft Academic Search

This paper describes Ni-ferrite formation in the presence of Li2SO4-Na2SO4 molten salts, and in particular the effects of the raw materials, amount of salts, heating temperature and time on the size and shape of the ferrite powders, as well as on the rate of ferrite formation. The molten salts accelerate ferrite formation and complete ferrite formation is attained at lower

Toshio Kimura; Tatsuya Takahashi; Takashi Yamaguchi

1980-01-01

176

Electroconductive polymer nanoparticles preparation and characterization of PANI and PEDOT nanoparticles  

Microsoft Academic Search

Nanoparticles of electroconductive polymers were prepared in micellar solution as a polymerization medium to overcome the poor processability of electroconductive polymers. The morphologies of particles were studied through SEM and electrical conductivities of pellets formed with nanoparticles were measured by four-probe apparatus. Among many other electroconductive polymers, nanoparticles of polyaniline and poly(3,4-ethylenedioxythiophene) were prepared in anionic sodium dodecyl sulfate and

Seong-Geun Oh; Seung-Soon Im

2002-01-01

177

A novel sonication route to prepare anthracene nanoparticles  

SciTech Connect

A novel sonication method has been successfully developed for the preparation of anthracene nanoparticles. The as-prepared nanoparticles are characterized using transmission electron microscopy, ultraviolet-visible absorption spectroscopy, fluorescence excitation and emission spectroscopy. Nanoparticles prepared with sonication are smaller and better dispersed than with magnetic stirring. Surfactants cetyltrimethylammonium bromide, bis(2-ethylhexyl)sodium sulfosuccinate, sodium dodecyl sulfonate and polyvinylpyrrolidone are used to control the size and morphology. Excimer band is found at 445 and 472 nm and possible mechanism is discussed.

Kang Peng; Chen Chunnian; Hao Lingyun; Zhu Chunling; Hu Yuan; Chen Zuyao

2004-04-02

178

Effects of Thermal Annealing on Structural and Magnetic Properties of Lithium Ferrite Nanoparticles  

SciTech Connect

Pure, crystalline, {approx}10 nm lithium ferrite phase (Li{sub 0.5}Fe{sub 2.5}O{sub 4}), was successfully synthesized at very low temperature using a modified combustion method. The crystal structure and microstructure evolution of this system upon annealing were monitored by a careful investigation of X-ray diffractograms collected on a synchrotron source. Comparative analysis of the results obtained from the full profile Rietveld method (in reciprocal space) and the pair distribution function method (in direct space) was carried out. Nanocrystalline samples exhibit similar crystal structure, on average, with a partial ordering of Li{sup +} and Fe{sup 3+} ions between octahedral 4b and 12d sites on the spinel crystal lattice (space group P4{sub 3}32). After annealing at 973 K, cation distribution changes to a completely ordered, resembling that which is seen in the bulk lithium ferrite. The PDF analysis reveals abnormally high values of oxygen atomic displacement parameters in tetrahedral 8c sites (O1) indicating a significant disordering of the O1 network and suggests migration of lithium ions from 4b sites to the outer layers of nanoparticles. Analysis of room temperature Moessbauer spectra has shown that the hyperfine field for Fe{sup 3+} ions in tetrahedral 8c sites is the most sensitive on increasing the particle size and improving the crystallinity. From the differential thermal analysis, it was found that a lower driving force is required to induce an order-disorder phase transition in nanocrystalline samples, compared to the bulk-like sample, presumably due to the higher crystal disordering in these samples.

Jovic, Natasa G.; Masadeh, Ahmad S.; Kremenovic, Aleksandar S.; Antic, Bratislav V.; Blanusa, Jovan L.; Cvjeticanin, Nikola D.; Goya, Gerardo F.; Antisari, Marco Vittori; Bozin, Emil S.; (FPC-Serbia); (MSU); (Zaragoza); (ENEA); (Columbia); (Vinca)

2010-01-12

179

Naproxen–eudragit ® RS100 nanoparticles: Preparation and physicochemical characterization  

Microsoft Academic Search

The objective of the present study was to formulate naproxen–eudragit® RS100 nanoparticles and investigate the physicochemical characteristics of the prepared nanoparticles. The nanoparticles of naproxen with eudragit® RS100 were formulated using the solvent evaporation\\/extraction technique (the single emulsion technique). The effect of several process parameters, i.e., drug\\/polymer ratio, aqueous phase volume and speed of homogenization were considered on the size

Khosro Adibkia; Yousef Javadzadeh; Siavoush Dastmalchi; Ghobad Mohammadi; Fatemeh Kari Niri; Mahmood Alaei-Beirami

2011-01-01

180

Magnetic properties of iron nanoparticles prepared by exploding wire technique  

Microsoft Academic Search

Nanoparticles of iron were prepared in distilled water using very thin iron wires and sheets, by the electro-exploding wire technique. Transmission electron microscopy reveals the size of the nanoparticles to be in the range 10 to 50 nm. However, particles of different sizes can be segregated by using ultrahigh centrifuge. X-ray diffraction studies confirm the presence of the cubic phase

Abdullah Alqudami; S. Annapoorni; Subhalakshmi Lamba; P C Kothari; R K Kotnala

2006-01-01

181

Structural, electrical and dielectric properties of spinel nickel ferrite prepared by soft mechanochemical synthesis  

SciTech Connect

Graphical abstract: - Highlights: • Sintered NiFe{sub 2}O{sub 4} was prepared by a soft mechanochemical route from mixture powders. • XRD and Raman measurements indicate that the prepared samples have spinel structure. • The activation energy ?E are 0.653 and 0.452 eV for NiFe{sub 2}O{sub 4} samples. • Ferrite from Ni(OH){sub 2}/Fe{sub 2}O{sub 3} has lower DC conductivity than from Ni(OH){sub 2}/Fe(OH){sub 3} powders. • The values of dielectric constant of samples NiFe{sub 2}O{sub 4} are 70 and 200, respectively. - Abstract: Nickel ferrite, NiFe{sub 2}O{sub 4} was prepared by a soft mechanochemical route from a mixture of (1) Ni(OH){sub 2} and ?-Fe{sub 2}O{sub 3} and (2) Ni(OH){sub 2} and Fe(OH){sub 3} powders in a planetary ball mill for 25 h. The powder samples were sintered at 1100 °C for 2 h and were characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). Impedance spectroscopy techniques were used to study the effect of grain and grain boundary on the electrical properties of the prepared samples. A difference in dielectric constant (?) and dielectric loss tangent (tan ?) of NiFe{sub 2}O{sub 4} samples obtained by the same methods but starting from different initial components was observed.

Lazarevi?, Zorica Ž., E-mail: lzorica@yahoo.com [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Jovaleki?, ?edomir [The Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade (Serbia); Sekuli?, Dalibor L. [Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovi?a 6, Novi Sad (Serbia); Milutinovi?, Aleksandra [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Baloš, Sebastian; Slankamenac, Miloš [Faculty of Technical Sciences, University of Novi Sad, Trg Dositeja Obradovi?a 6, Novi Sad (Serbia); Rom?evi?, Nebojša Ž. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia)

2013-10-15

182

Synthesis and assembly of high-quality cobalt ferrite nanocrystals prepared by a modified sol–gel technique  

Microsoft Academic Search

Colloidal cobalt ferrite nanocrystals were produced using a new sol–gel-like synthesis based on the procedure developed by O’Brien et al. (J. Am. Chem. Soc. 123 (2001) 12085) for the synthesis of BaTiO3 nanocrystals. This synthesis involves the single-stage high-temperature hydrolysis of the metal alkoxide precursors to obtain crystalline, uniform, organically coated nanoparticles which are well-dispersed in an organic solvent. The

Tal Meron; Yuri Rosenberg; Yossi Lereah; Gil Markovich

2005-01-01

183

Effects of Rare Earth Oxides on Some Physical Properties of Li-Zn Nanoparticle Ferrites  

NASA Astrophysics Data System (ADS)

The spinel ferrite Li0.2Zn0.6LayFe2.2-yO4; 0.01 ? y ? 0.1 were prepared by the usual ceramic sintering technique. XRD confirmed the formation of the samples in single phase spinel structure for all the samples. The lattice parameters decreased with increasing the La-content. The d c resistivity was measured as a function of temperature. The obtained results indicate the semiconductor like behavior, where more than straight lines indicating the presence of different conductions mechanism exist. The density of states near Fremi level as a function of La-content and discussed based on the variable range hoping model. The dielectric constant and dielectric loss were measured as a function of temprature and frequency. The dispersion peak at low frequency (10 kHz) was splitted by increasing La-content up to the suggested absorber splitting.

Ahmed, M. A.; Okasha, N.; Ali, A. I.; Hammam, M.; Song, J. Y.

2011-06-01

184

Nanoparticles of Molybdenum Chlorophyllin Photosensitizer and Magnetic Citrate-Coated Cobalt Ferrite Complex Available to Hyperthermia and Photodynamic Therapy Clinical Trials  

NASA Astrophysics Data System (ADS)

This study report on the synthesis and characterization of molybdenum chlorophyllin (Mo-Chl) compounds associated in a complex with magnetic nanoparticles (citrate-coated cobalt ferrite), the latter prepared as a biocompatible magnetic fluid (MF). The complex material was developed for application as a synergic drug for cancer treatment using Photodynamic Therapy (PDT) and Hyperthermia (HPT). Chlorophyllin was obtained from alkaline extraction of Ilex paraguariensis following molybdenum insertion from hydrolysis with molybdate sodium. Fluorescence quantum yield (?f) of Mo-Chl/dimethyl-sulphoxide (DMSO) was lower than 0.1, with a lifetime of 5.0 ns, as obtained from time-correlated single-photon counting technique. The oxygen quantum yield of Mo-Chl was carried out using laser flash-photolysis studies in homogeneous medium saturated with O2(g) (?? = 0.50). Cellular viability was also evaluated via the classical MTT assay using gingival fibroblasts cells as a biological model. Studies performed with the complex Mo-Chl (5.0 ?mol.L-1)/MF at different magnetic nanoparticle concentrations (ranging from 1012 to 1015 particle.mL-1) revealed a cellular viability of approximately 95% for the ideal magnetic material concentration of 1×10 particle.mL-1. The present study shows that natural photosensitizers molecules Mo-Chl used in association with magnetic nanoparticles represent a promising generation of drug developed to work synergistically in the treatment of neoplastic tissues using PDT and HPT.

Primo, Fernando L.; Cordo, Paloma L. A. G.; Neto, Alberto F.; Morais, Paulo C.; Tedesco, Antonio C.

2010-12-01

185

Preliminary evaluation of a 99mTc labeled hybrid nanoparticle bearing a cobalt ferrite core: in vivo biodistribution.  

PubMed

Magnetic nanoparticles have become important tools for imaging a wide range of diseases, improving drug delivery and applying hyperthermic treatment. Iron oxide based nanoparticles have been widely examined, unlike cobalt ferrite based ones. Herein, monodisperse and stable CoFe2O4 nanoparticles have been produced, coated and further stabilized using ethyl 12-(hydroxyamino)-12-oxododecanoate, poly(lactic-co-glycolic acid) and bovine serum albumin. The final product, NBRh1, was fully characterized and has been directly radiolabeled with 99mTc using SnCl1 as the reducing agent in high yields. In vitro stability and hyperthermic properties of 99mTC-NBRh1 were encouraging for further application in low frequencies hyperthermia and biomagnetic applications. In vivo evaluation followed after injection in healthy mice. The planar and SPECT imaging data as well as the biodistribution results were in accordance, showing high liver and spleen uptake as expected starting almost immediately after administration. In conclusion the preliminary results for nanoparticles bearing a cobalt ferrite core justify further investigations towards potential hyperthermic applications, drug transportation and liver or spleen imaging. PMID:22852467

Psimadas, Dimitrios; Baldi, Giovanni; Ravagli, Costanza; Bouziotis, Penelope; Xanthopoulos, Stavros; Franchini, Mauro Comes; Georgoulias, Panagiotis; Loudos, George

2012-08-01

186

Adsorption of cobalt ferrite nanoparticles within layer-by-layer films: a kinetic study carried out using quartz crystal microbalance.  

PubMed

The paper reports on the successful use of the quartz crystal microbalance technique to assess accurate kinetics and equilibrium parameters regarding the investigation of in situ adsorption of nanosized cobalt ferrite particles (CoFe(2)O(4)--10.5 nm-diameter) onto two different surfaces. Firstly, a single layer of nanoparticles was deposited onto the surface provided by the gold-coated quartz resonator functionalized with sodium 3-mercapto propanesulfonate (3-MPS). Secondly, the layer-by-layer (LbL) technique was used to build multilayers in which the CoFe(2)O(4) nanoparticle-based layer alternates with the sodium sulfonated polystyrene (PSS) layer. The adsorption experiments were conducted by modulating the number of adsorbed CoFe(2)O(4)/PSS bilayers (n) and/or by changing the CoFe(2)O(4) nanoparticle concentration while suspended as a stable colloidal dispersion. Adsorption of CoFe(2)O(4) nanoparticles onto the 3-MPS-functionalized surface follows perfectly a first order kinetic process in a wide range (two orders of magnitude) of nanoparticle concentrations. These data were used to assess the equilibrium constant and the adsorption free energy. Alternatively, the Langmuir adsorption constant was obtained while analyzing the isotherm data at the equilibrium. Adsorption of CoFe(2)O(4) nanoparticles while growing multilayers of CoFe(2)O(4)/PSS was conducted using colloidal suspensions with CoFe(2)O(4) concentration in the range of 10(-8) to 10(-6) (moles of cobalt ferrite per litre) and for different numbers of cycles n = 1, 3, 5, and 10. We found the adsorption of CoFe(2)O(4) nanoparticles within the CoFe(2)O(4)/PSS bilayers perfectly following a first order kinetic process, with the characteristic rate constant growing with the increase of CoFe(2)O(4) nanoparticle concentration and decreasing with the rise of the number of LbL cycles (n). Additionally, atomic force microscopy was employed for assessing the LbL film roughness and thickness. We found the film thickness increasing from about 20 to 120 nm while shifting from 3 to 10 CoFe(2)O(4)/PSS bilayers, using the 8.9 × 10(-6) (moles of cobalt ferrite per litre) suspension. PMID:22025281

Alcantara, Gustavo B; Paterno, Leonardo G; Afonso, André S; Faria, Ronaldo C; Pereira-da-Silva, Marcelo A; Morais, Paulo C; Soler, Maria A G

2011-12-28

187

Preparation and properties of barium ferrite using hot-rolled mill scale  

SciTech Connect

Commercial-quality barium ferrite was made on a laboratory scale by the solid-state reaction of raw hot-rolled mill scale and barium carbonate. The processing parameters are reported. The mechanism of ferrite formation is proposed.

Chien, Y.T.; Pan, H.C.; Ko, Y.C. (China Steel Corp., Kaohsiung, Taiwan (TW))

1989-08-01

188

Naproxen-eudragit RS100 nanoparticles: preparation and physicochemical characterization.  

PubMed

The objective of the present study was to formulate naproxen-eudragit RS100 nanoparticles and investigate the physicochemical characteristics of the prepared nanoparticles. The nanoparticles of naproxen with eudragit RS100 were formulated using the solvent evaporation/extraction technique (the single emulsion technique). The effect of several process parameters, i.e., drug/polymer ratio, aqueous phase volume and speed of homogenization were considered on the size of the nanoformulations. The physicochemical characteristics of nanoparticles were studied applying particle size analysis, differential scanning calorimetry, X-ray crystallography, Fourier transform infrared spectroscopy and scanning electron microscopy. The release rate of naproxen from various drug/polymer nanoparticles was investigated as well. All the prepared formulations using eudragit RS100 resulted in nano-range size particles with relative spherical smooth morphology. The nanoparticles of naproxen-eudragit RS100 displayed lower crystallinity. The intermolecular interaction between naproxen and eudragit RS100 was detected in the FT-IR spectrum of the nanoparticles. All the nanoparticles displayed a slowed release pattern with the reduced burst release in comparison with the intact drug powder and physical mixtures of drug and polymer. According of these findings, formulation of the naproxen-eudragit RS100 nanoparticles was able to improve the physicochemical characteristics of the drug and possibly will increase the anti-inflammatory effects of drug following its ocular or intra-joint administration. PMID:21130612

Adibkia, Khosro; Javadzadeh, Yousef; Dastmalchi, Siavoush; Mohammadi, Ghobad; Niri, Fatemeh Kari; Alaei-Beirami, Mahmood

2011-03-01

189

Antifungal activity of gold nanoparticles prepared by solvothermal method  

SciTech Connect

Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ? Effect of reducing agents on the morphology of gold nanoparticles. ? Highly uniform and monodisperse gold nanoparticles (7 nm). ? Highest surface area of gold nanoparticles (329 m{sup 2/}g). ? Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract: Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.

Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India)] [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India)] [Nanochemistry Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025 (India); Manzoor, Nikhat; Ahmad, Aijaz [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India)] [Department of Biosciences, Jamia Millia Islamia, New Delhi 110025 (India); Ahmed, Jahangeer [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States)] [Department of Chemistry, Michigan State University, East Lansing, MI 48824 (United States); Al-Shihri, Ayed S. [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)] [Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P.O. Box 9004 (Saudi Arabia)

2013-01-15

190

Preparation and characterization of hollow glass microspheres coated by CoFe 2O 4 nanoparticles using urea as precipitator via coprecipitation method  

Microsoft Academic Search

The composite of hollow glass microspheres coated by CoFe2O4 nanoparticles has been successfully prepared using urea as precipitator via coprecipitation method. The resultant composites were characterized by X-ray diffraction, field emission scanning electron microscope and vibrating sample magnetometer. The results showed that the slow decomposition of urea could be beneficial to form uniform and entire cobalt ferrite coating layer on

Xiaofen Pang; Wuyou Fu; Haibin Yang; Hongyang Zhu; Jing Xu; Xiang Li; Guangtian Zou

2009-01-01

191

Spark plasma sintering of cobalt ferrite nanopowders prepared by coprecipitation and hydrothermal synthesis  

Microsoft Academic Search

Cobalt ferrite exhibits a high coercivity at room temperature and a strong magnetic anisotropy compared to the other spinel ferrites and, consequently appears as an interesting material for permanent magnets and high-density recording. The magnetic properties depend also on the crystallite size. In order to keep the powder properties in a bulk material, dense nanostructured cobalt ferrite has to be

N. Millot; S. Le Gallet; D. Aymes; F. Bernard; Y. Grin

2007-01-01

192

Growth and characterization of ferrite film prepared by pulsed laser deposition  

E-print Network

spectroscopy (XPS) shows the signature of all the elements present in the barium ferrite. XRR data show contains ferrimagnetic compounds with easy axis of magnetization (e.g. M-type ferrites) and easy plane of magnetization (e.g. Y-type ferrites). Hence, hexaferrites have been widely adopted in two distinct fields

Paris-Sud XI, Université de

193

Zero-valent iron nanoparticles preparation  

SciTech Connect

Graphical abstract: Zero-valent iron nanoparticles were synthesized by hydrogenating [Fe[N(Si(CH{sub 3}){sub 3}){sub 2}]{sub 2}] at room temperature and a pressure of 3 atm. The synthesized nanoparticles were spherical and had diameters less than 5 nm. Highlights: ? Zero-valent iron nanoparticles were synthesized by hydrogenating [Fe[N(Si(CH{sub 3}){sub 3}){sub 2}]{sub 2}]. ? The conditions of reaction were at room temperature and a pressure of 3 atm. ? The synthesized nanoparticles were spherical and had diameters less than 5 nm. -- Abstract: Zero-valent iron nanoparticles were synthesized by hydrogenating [Fe[N(Si(CH{sub 3}){sub 3}){sub 2}]{sub 2}] at room temperature and a pressure of 3 atm. To monitor the reaction, a stainless steel pressure reactor lined with PTFE and mechanically stirred was designed. This design allowed the extraction of samples at different times, minimizing the perturbation in the system. In this way, the shape and the diameter of the nanoparticles produced during the reaction were also monitored. The results showed the production of zero-valent iron nanoparticles that were approximately 5 nm in diameter arranged in agglomerates. The agglomerates grew to 900 nm when the reaction time increased up to 12 h; however, the diameter of the individual nanoparticles remained almost the same. During the reaction, some byproducts constituted by amino species acted as surfactants; therefore, no other surfactants were necessary.

Oropeza, S. [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico)] [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico); Corea, M., E-mail: mcoreat@yahoo.com.mx [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico); Gómez-Yáñez, C. [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico)] [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico); Cruz-Rivera, J.J. [Universidad Autónoma de San Luis Potosí, Instituto de Metalurgia, Sierra Leona 550, San Luis Potosí, C.P. 78210 (Mexico)] [Universidad Autónoma de San Luis Potosí, Instituto de Metalurgia, Sierra Leona 550, San Luis Potosí, C.P. 78210 (Mexico); Navarro-Clemente, M.E., E-mail: mnavarroc@ipn.mx [Instituto Politécnico Nacional, ESIQIE, UPALM, Edificio Z-6, Primer Piso, C.P. 07738, Col. San Pedro Zacatenco, México D.F. (Mexico)

2012-06-15

194

Preparation and magnetic properties of barium ferrites substituted with manganese, cobalt, and tin  

Microsoft Academic Search

Barium ferrites substituted by Mn–Sn, Co–Sn, and Mn–Co–Sn with general formulae BaFe12?2xMnxSnxO19 (x=0.2–1.0), BaFe12?2xCoxSnxO19 (x=0.2–0.8), and BaFe12?2xCox\\/2Mnx\\/2SnxO19 (x=0.1–0.6), respectively, have been prepared by a previously reported co-precipitation method. The efficiency of the method was refined by lowering the reaction temperature and shortening the required reaction time, due to which crystallinity improved and the value of saturated magnetization increased as well.

Yue Liu; Michael G. B. Drew; Ying Liu

2011-01-01

195

Low temperature synthesis of bismuth ferrite nanoparticles by a ferrioxalate precursor method  

Microsoft Academic Search

The synthesis of bismuth ferrite by solid-state reaction of Bi2O3 and Fe2O3 results in the formation of multiphase products. Even coprecipitation followed by calcination leads to the formation of impurity phases. Here, we report the synthesis of magnetoelectric bismuth ferrite by a ferrioxalate precursor method. In this process, bismuth ferrite, synthesized through solutions of some specific salts led to the

Sushmita Ghosh; Subrata. Dasgupta; Amarnath Sen; Himadri Sekhar Maiti

2005-01-01

196

Environmentally friendly preparation of metal nanoparticles  

EPA Science Inventory

The book chapter summarizes the ?state of the art? in the exploitation of various environmentally-friendly synthesis approaches, reaction precursors and conditions to manufacture metal and metal oxide nanoparticles for a vast variety of purposes....

197

Magnetic and optical properties of multiferroic bismuth ferrite nanoparticles by tartaric acid-assisted sol–gel strategy  

Microsoft Academic Search

Pure BiFeO3 nanoparticles have been successfully synthesized through the tartaric acid-assisted sol–gel method at relatively low temperature. The as-prepared nanoparticles were characterized by a variety of techniques. The success in preparing pure BiFeO3 may be attributed to the formation of heterometallic polynuclear complexes in the tartaric acid system. The ferroelectric phase transition (TC=851°C) was determined, revealing the ferroelectric nature of

Xiong Wang; Yan'ge Zhang; Zhibin Wu

2010-01-01

198

Electrospinning preparation, characterization and magnetic properties of cobalt-nickel ferrite (Co(1-x)Ni(x)Fe2)O4) nanofibers.  

PubMed

Uniform Co(1-)(x)Ni(x)Fe(2)O(4) (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanofibers with average diameter of 110 nm and length up to several millimeters were prepared by calcination of electrospun precursor nanofibers containing polymer and inorganic salts. The as-spun and calcined nanofibers were characterized in detail by TG-DTA, XRD, FE-SEM, TEM, SAED and VSM, respectively. The effect of composition of the nanofibers on the structure and magnetic properties were investigated. The nanofibers are formed through assembling magnetic nanoparticles with poly(vinyl pyrrolidone) as the structure-directing template. The structural characteristics and magnetic properties of the resultant nanofibers vary with chemical composition and can be tuned by adjusting the Co/Ni ratio. Both lattice parameter and particle size decrease gradually with increasing nickel concentration. The saturation magnetization and coercivity lie in the range 29.3-56.4 emu/g and 210-1255 Oe, respectively, and both show a monotonously decreasing behavior with the increase in nickel concentration. Such changes in magnetic properties can mainly be attributed to the lower magnetocrystalline anisotropy and the smaller magnetic moment of Ni(2+) ions compared to Co(2+) ions. Furthermore, the coercivity of Co-Ni ferrite nanofibers is found to be superior to that of the corresponding nanoparticle counterparts, presumably due to their large shape anisotropy. These novel one-dimensional Co-Ni ferrite magnetic nanofibers can potentially be used in micro-/nanoelectronic devices, microwave absorbers and sensing devices. PMID:22456275

Xiang, Jun; Chu, Yanqiu; Shen, Xiangqian; Zhou, Guangzhen; Guo, Yintao

2012-06-15

199

Preparation and characterization of hollow glass microspheres coated by CoFe{sub 2}O{sub 4} nanoparticles using urea as precipitator via coprecipitation method  

SciTech Connect

The composite of hollow glass microspheres coated by CoFe{sub 2}O{sub 4} nanoparticles has been successfully prepared using urea as precipitator via coprecipitation method. The resultant composites were characterized by X-ray diffraction, field emission scanning electron microscope and vibrating sample magnetometer. The results showed that the slow decomposition of urea could be beneficial to form uniform and entire cobalt ferrite coating layer on the surface of hollow glass microspheres. The smoothest morphology was obtained for the sample prepared from 0.7 M urea, while the sample prepared from 1.0 M urea had the thickest shell. This indicated that there was a competition between the morphology and thickness of the coated microspheres. A possible formation mechanism of hollow glass microspheres coated with cobalt ferrite was proposed. The magnetic properties of the samples were also investigated.

Pang Xiaofen; Fu Wuyou [National Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Yang Haibin [National Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)], E-mail: yanghb@jlu.edu.cn; Zhu Hongyang; Xu Jing [National Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Li Xiang [Institute of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003 (China); Zou Guangtian [National Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China)

2009-02-04

200

Barium ferrite powders prepared by microwave-induced combustion process and some of their properties  

Microsoft Academic Search

Barium ferrite powders were successfully synthesized by a microwave-induced combustion process. The process takes only a few minutes to obtain calcined barium ferrite powders. The resultant powders were investigated by XRD, SEM, VSM, TG\\/DTA, and a surface area measurement. The as-received product shows the barium ferrite with saturation magnetization (Ms)?23 emu\\/g and an intrinsic coercive force (iHc) of 595 Oe,

Yen-Pei Fu; Cheng-Hsiung Lin; Ko-Ying Pan

2004-01-01

201

Nanowires of NiCo\\/barium ferrite magnetic composite by electrodeposition  

Microsoft Academic Search

Electrodeposition has been demonstrated to be useful in preparing well defined composite nanowires and as a way to modify their magnetic properties. A sulphamate bath containing barium ferrite nanoparticles has been used to test nanoparticle incorporation during an alloy (NiCo) electrodeposition process. The nanoparticles enter the membrane pores during the electrodeposition, being uniformly distributed into them.Home-made alumina membranes prepared in

P. Cojocaru; L. Magagnin; E. Gomez; E. Vallés

2011-01-01

202

Structural, dielectric and magnetic properties of cobalt ferrite prepared using auto combustion and ceramic route  

NASA Astrophysics Data System (ADS)

Cobalt ferrite is synthesized by using low temperature auto combustion and high temperature ceramic methods. The prepared samples have values of lattice constant equal to 8.40 Å and 8.38 Å for auto combustion and ceramic methods respectively. The FTIR spectrum of samples of the auto combustion method shows a high frequency vibrational band at 580 cm-1 assigned to tetrahedral site and a low frequency vibrational band at 409 cm-1 assigned to octahedral site which are shifted to 590 cm-1 and 412 cm-1 for the ceramic method sample. SEM micrographs of samples show a substantial difference in surface morphology and size of the grains between the two methods. The frequency dependent dielectric constant and ac conductivity of the samples measured from 1 Hz to 2 MHz at room temperature are reported. The room temperature magnetic hysteresis parameters of the samples are measured using VSM. The measured values of saturation magnetization, coercivity and remanent magnetization are 42 emu/g, 1553 Oe, 18.5 emu/g for the auto combustion method, 66.7 emu/g, 379.6 Oe, and 17.3 emu/g for the ceramic method, respectively. The difference in preparation methods and size of the grains causes interesting changes in electrical and magnetic properties.

Murugesan, C.; Perumal, M.; Chandrasekaran, G.

2014-09-01

203

Microwave-absorbing characteristics of epoxy resin composites containing nanoparticles of NiZn- and NiCuZn-ferrites  

NASA Astrophysics Data System (ADS)

NiZn- and NiCuZn-ferrite nanoparticles (50-70 nm) with the chemical formula Ni 0.5 Zn 0.5Fe 2O 4 (NiZn) and Ni 0.35Cu 0.15Zn 0.5Fe 2O 4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83 emu/g (NiZn) to 91 emu/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in the frequency range of 1 MHz-1.8 GHz. Reflection losses ( RL) for both samples were calculated from complex permeability and permittivity. Cu substitution in NiZn-ferrite enhances permeability and RL. In order to explore microwave-absorbing properties in X-band, magnetic nanoparticles were mixed with an epoxy resin to be converted into a microwave-absorbing composite and microwave behaviors of both materials were studied using a microwave vector network analyzer from 7.5 to 13.5 GHz. Cu substitution diminishes absorption intensity in the range 11.5-12.5 GHz.

Aphesteguy, J. C.; Damiani, Abel; DiGiovanni, Dalmas; Jacobo, S. E.

2009-10-01

204

Low temperature-fired Ni-Cu-Zn ferrite nanoparticles through auto-combustion method for multilayer chip inductor applications  

PubMed Central

Ferrite nanoparticles of basic composition Ni0.7-xZnxCu0.3Fe2O4 (0.0 ? x ? 0.2, x = 0.05) were synthesized through auto-combustion method and were characterized for structural properties using X-ray diffraction [XRD], scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy [FT-IR]. XRD analysis of the powder samples sintered at 600°C for 4 h showed the cubic spinel structure for ferrites with a narrow size distribution from 28 to 32 nm. FT-IR showed two absorption bands (v1 and v2) that are attributed to the stretching vibration of tetrahedral and octahedral sites. The effect of Zn doping on the electrical properties was studied using dielectric and impedance spectroscopy at room temperature. The dielectric parameters (?', ??, tan?, and ?ac) show their maximum value for 10% Zn doping. The dielectric constant and loss tangent decrease with increasing frequency of the applied field. The results are explained in the light of dielectric polarization which is similar to the conduction phenomenon. The complex impedance shows that the conduction process in grown nanoparticles takes place predominantly through grain boundary volume. PACS: 75.50.Gg; 78.20; 77.22.Gm. PMID:22316055

2012-01-01

205

Preparation and characterization of nanosize nickel-substituted cobalt ferrites (Co 1? x Ni x Fe 2O 4)  

Microsoft Academic Search

Nanosize nickel-substituted cobalt ferrites were prepared using aerosol route and characterized by TEM, XRD, magnetic and Mössbauer spectroscopy. The particle size of as obtained samples was found to be ?10nm which increases upto ?80nm on annealing at 1200°C. The unit cell parameter ‘a’ decreases linearly with the nickel concentration due to smaller ionic radius of nickel. The saturation magnetization for

Sonal Singhal; J. Singh; S. K Barthwal; K. Chandra

2005-01-01

206

Influence of acid catalysts on the structural and magnetic properties of nanocrystalline barium ferrite prepared by sol–gel method  

Microsoft Academic Search

BaFe12O19 powders with nanocrystalline size were prepared by sol–gel techniques. Nitric, hydrochloric, acetic and stearic acid were used to improve the magnetic properties. Amorphous gels were formed with Fe\\/Ba molar ratio of 10.5. Then powders were obtained by subsequent heat treatment at 800–1000°C for 1h. Barium ferrite powder was also synthesized by solid state reaction at 1210°C. X-ray diffraction, scanning

Ebrahim Paimozd; Ali Ghasemi; Abdolhamid Jafari; Hassan Sheikh

2008-01-01

207

Synthesis and characterization of hard magnetic composite photocatalyst—Barium ferrite\\/silica\\/titania  

Microsoft Academic Search

Hard magnetic composite photocatalytic particles—barium ferrite (magnetic core)\\/silica (intermediate layer)\\/titania (photoactive shell) (B\\/S\\/T) were prepared by wet-chemical methods. Anatase titania nanoparticles were directly coated on the silica-coated barium ferrite forming photoactive titania shell by hydrolysis and condensation of titanium n-butoxide. The prepared hard magnetic composite photocatalyst can be magnetically fluidized and recovered by an applied magnetic field enhancing both the

Seung-woo Lee; Jack Drwiega; David Mazyck; Chang-Yu Wu; Wolfgang M. Sigmund

2006-01-01

208

Magnetic and dielectric properties of barium titanate-coated barium ferrite  

Microsoft Academic Search

Flaky barium ferrite with hexagonal molecular structure was successfully prepared by reverse microemulsion method, and was coated with barium titanate through a coordination–precipitation technique. The prepared composite particles were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), vibrating sample magnetometry (VSM) and vector network analyzer. Barium ferrite nanoparticles are proved to be single magnetic

Chao Wang; Xijiang Han; Ping Xu; Xiaohong Wang; Xueai Li; Hongtao Zhao

2009-01-01

209

Preparation, characterization and optimization of glipizide controlled release nanoparticles  

PubMed Central

The purpose of the present study was to develop glipizide controlled release nanoparticles using alginate and chitosan thorough ionotropic controlled gelation method. Glipizide is a frequently prescribed second generation sulfonylurea which lowers the blood glucose in type-two diabetics. Quick absorption of the drug from the gastrointestinal tract along with short half- life of elimination makes it a good candidate for controlled release formulations. Alginate-chitosan nanoparticles (ACNP) are convenient controlled delivery systems for glipizide, due to both the release limiting properties of the system, and the bioadhesive nature of the polymers. In the present study, glipizide loaded alginate-chitosan nanoparticles (GlACNP) were prepared, and the particle characteristics including particle size (PS), zeta potential (ZP), entrapment efficiency (EE%), loading percent (LP), and mean release time (MRT), as well as the morphology of the nanoparticles, the drug-excipient compatibility, and the release kinetics along with the drug diffusion mechanism were evaluated. The results suggested that ionotropic controlled gelation method offers the possibility of preparing the nanoparticles in mild conditions in an aqueous environment, and can lead to the preparation of particles with favorable size, controlled release characteristics, and high entrapment efficiency, serving as a convenient delivery system for glipizide. The particle and release characteristics can be efficiently optimized using the Box-Behnken design. Based on the findings of the present study, it is expected that this novel formulation be a superior therapeutic alternative to the currently available glipizide delivery systems. PMID:25657802

Emami, J.; Boushehri, M.S. Shetab; Varshosaz, J.

2014-01-01

210

Preparation, characterization and optimization of glipizide controlled release nanoparticles.  

PubMed

The purpose of the present study was to develop glipizide controlled release nanoparticles using alginate and chitosan thorough ionotropic controlled gelation method. Glipizide is a frequently prescribed second generation sulfonylurea which lowers the blood glucose in type-two diabetics. Quick absorption of the drug from the gastrointestinal tract along with short half- life of elimination makes it a good candidate for controlled release formulations. Alginate-chitosan nanoparticles (ACNP) are convenient controlled delivery systems for glipizide, due to both the release limiting properties of the system, and the bioadhesive nature of the polymers. In the present study, glipizide loaded alginate-chitosan nanoparticles (GlACNP) were prepared, and the particle characteristics including particle size (PS), zeta potential (ZP), entrapment efficiency (EE%), loading percent (LP), and mean release time (MRT), as well as the morphology of the nanoparticles, the drug-excipient compatibility, and the release kinetics along with the drug diffusion mechanism were evaluated. The results suggested that ionotropic controlled gelation method offers the possibility of preparing the nanoparticles in mild conditions in an aqueous environment, and can lead to the preparation of particles with favorable size, controlled release characteristics, and high entrapment efficiency, serving as a convenient delivery system for glipizide. The particle and release characteristics can be efficiently optimized using the Box-Behnken design. Based on the findings of the present study, it is expected that this novel formulation be a superior therapeutic alternative to the currently available glipizide delivery systems. PMID:25657802

Emami, J; Boushehri, M S Shetab; Varshosaz, J

2014-01-01

211

Preparation of candesartan and atorvastatin nanoparticles by solvent evaporation.  

PubMed

The solubility, absorption and distribution of a drug are involved in the basic aspects of oral bioavailability Solubility is an essential characteristic and influences the efficiency of the drug. Over the last ten years, the number of poorly soluble drugs has steadily increased. One of the progressive ways for increasing oral bioavaibility is the technique of nanoparticle preparation, which allows many drugs to thus reach the intended site of action. Candesartan cilexetil and atorvastatin, belonging to class II of the biopharmaceutical classification system, were chosen as model active pharmaceutical ingredients in this study. Forty samples were prepared either by antisolvent precipitation/solvent evaporation method or by the emulsion/solvent evaporation technique with various commonly used surface-active excipients as nanoparticle stabilizers. All samples were analyzed by means of dynamic light scattering. The particle size of the determined 36 nanoparticle samples was to 574 nm, whereas 32 samples contained nanoparticles of less than 200 nm. Relationships between solvents and excipients used and their amount are discussed. Based on the results the investigated solvent evaporation methods can be used as an effective and an affordable technique for the preparation of nanoparticles. PMID:23132139

Vaculikova, Eliska; Grunwaldova, Veronika; Kral, Vladimir; Dohnal, Jiri; Jampilek, Josef

2012-01-01

212

Low temperature synthesis of bismuth ferrite nanoparticles by a ferrioxalate precursor method  

SciTech Connect

The synthesis of bismuth ferrite by solid-state reaction of Bi{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} results in the formation of multiphase products. Even coprecipitation followed by calcination leads to the formation of impurity phases. Here, we report the synthesis of magnetoelectric bismuth ferrite by a ferrioxalate precursor method. In this process, bismuth ferrite, synthesized through solutions of some specific salts led to the formation of phase pure (perovskite) nanocrystalline powder (11-22 nm as evident from X-ray diffraction analysis) at a temperature of 600 deg. C. The synthesized powders were characterized by X-ray diffractometry, thermogravimetry and differential thermal analysis, Fourier transformation infrared spectroscopy and scanning electron microscopy. The synthesis route is simple, energy saving and cost-effective. Such nanosized bismuth ferrite powder may have a potential application in making lead free piezoelectric materials for actuators as well as magnetoelectric sensors.

Ghosh, Sushmita [Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata, West Bengal 700032 (India); Dasgupta, Subrata [Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata, West Bengal 700032 (India)]. E-mail: sdasgupta@cgcri.res.in; Sen, Amarnath [Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata, West Bengal 700032 (India); Maiti, Himadri Sekhar [Central Glass and Ceramic Research Institute, 196 Raja S.C. Mullick Road, Kolkata, West Bengal 700032 (India)

2005-12-08

213

Preparation of mesoporous cadmium sulfide nanoparticles with moderate pore size  

SciTech Connect

The preparation of cadmium sulfide nanoparticles that have a moderate pore size is reported. This preparation method involves a hydrothermal process that produces a precursor mixture and a following acid treatment of the precursor to get the porous material. The majority of the particles have a pore size close to 20nm, which complements and fills in the gap between the existing cadmium sulfide materials, which usually have a pore size either less than 10nm or are well above 100nm.

Han Zhaohui [Nanochemistry Research Institute, Department of Applied Chemistry, Curtin University of Technology, WA 6102 (Australia); Australian Key Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia)], E-mail: zhaohui.han@curtin.edu.au; Zhu, Huaiyong [Australian Key Centre for Microscopy and Microanalysis, University of Sydney, NSW 2006 (Australia); Shi, Jeffrey [Department of Chemical Engineering, University of Sydney, NSW 2006 (Australia); Parkinson, Gordon [Nanochemistry Research Institute, Department of Applied Chemistry, Curtin University of Technology, WA 6102 (Australia); Lu, G.Q. [ARC Centre for Functional Nanomaterials, University of Queensland, Qld 4072 (Australia)

2007-03-15

214

Magnetoelectric behavior of carbonyl iron mixed Mn oxide-coated ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

The dielectric and magnetic properties of manganese oxide-coated Fe3O4 nanoparticles (NPs) were measured by the cavity perturbation method at x-band microwave frequencies ranging from 7-12.5 GHz with controlled external magnetic field up to 2.2 kOe at room temperature. Different ratios (5%, 10%, and 20% by weight) of coated NPs were prepared by sol-gel method then mixed with carbonyl iron powder in epoxy matrix. The saturation magnetization is inversely proportional to the NPs ratio in the mixture between 150 and 180 emu/g. The real part of the permittivity decreased with increasing NPs concentration, but the permittivity change by magnetic field increased. The tunability behavior is explained by insulator-ferromagnetic interface magnetoelectricity and the large surface volume ratio for the NPs.

Ahad, Faris B. Abdul; Lee, Shang-Fan; Hung, Dung-Shing; Yao, Yeong-Der; Yang, Ruey-Bin; Lin, Chung-Kwei; Tsay, Chien-Yie

2010-05-01

215

Composition and hydrophilicity control of Mn-doped ferrite (MnxFe3-xO4) nanoparticles induced by polyol differentiation.  

PubMed

Manganese doped ferrite (MnxFe3-xO4) nanoparticles with x = 0.29-0.77 were prepared under solvothermal conditions in the presence solely of a polyol using the trivalent manganese and iron acetylacetonates as precursors. In this facile approach, a variety of polyols such as polyethylene glycol (PEG 8000), tetraethylene glycol (TEG), propylene glycol (PG) and a mixture of TEG and PG (1?:?1) were utilized in a triple role as a solvent, a reducing agent and a surface-functionalizing agent. The composition of the fine cubic-spinel structures was found to be related to the reductive ability of each polyol, while determination of structural characteristics plus the inversion parameter (i = 0.18-0.38) were provided by X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy at both the Fe and Mn K-edges. The saturation magnetization increased up to 80 emu g(-1) when x = 0.35 and i = 0.22. In addition, the as-prepared nanocrystals coated with PEG, PG and PG&TEG showed excellent colloidal stability in water, while the TEG-coated particles were not water dispersible and converted to hydrophilic when were extra PEGylated. Measurements of the (1)H NMR relaxation in water were carried out and the nanoprobes were evaluated as potential contrast agents. PMID:25689845

Vamvakidis, Kosmas; Katsikini, Maria; Vourlias, George; Angelakeris, Mavroeidis; Paloura, Eleni C; Dendrinou-Samara, Catherine

2015-03-10

216

Preparation and immunological effectiveness of a swine influenza DNA vaccine encapsulated in chitosan nanoparticles  

Microsoft Academic Search

Preparation conditions of a DNA vaccine against swine influenza encapsulated in chitosan nanoparticles were determined. The nanoparticles were prepared according to a complex coacervation method using chitosan as a biodegradable matrix forming polymer. Under the preparation conditions, chitosan nanoparticles containing the DNA vaccine were produced with good morphology, high encapsulation rate and high stability. Transfection test indicated that the vaccine

Kai Zhao; Xingming Shi; Yan Zhao; Haixia Wei; Qingshen Sun; Tingting Huang; Xiaoyan Zhang; Yunfeng Wang

2011-01-01

217

Long-circulating PEGylated manganese ferrite nanoparticles for MRI-based molecular imaging  

NASA Astrophysics Data System (ADS)

Magnetic resonance based molecular imaging has emerged as a very promising technique for early detection and treatment of a wide variety of diseases, including cancer, neurodegenerative disorders, and vascular diseases. The limited sensitivity and specificity of conventional MRI are being overcome by the development of a new generation of contrast agents, using nanotechnology approaches, with improved magnetic and biological properties. In particular, for molecular imaging, high specificity, high sensitivity, and long blood circulation times are required. Furthermore, the lack of toxicity and immunogenicity together with low-cost scalable production are also necessary to get them into the clinics. In this work, we describe a facile, robust and cost-effective ligand-exchange method to synthesize dual T1 and T2 MRI contrast agents with long circulation times. These contrast agents are based on manganese ferrite nanoparticles (MNPs) between 6 and 14 nm in size covered by a 3 kDa polyethylene glycol (PEG) shell that leads to a great stability in aqueous media with high crystallinity and magnetization values, thus retaining the magnetic properties of the uncovered MNPs. Moreover, the PEGylated MNPs have shown different relaxivities depending on their size and the magnetic field applied. Thus, the 6 nm PEGylated MNPs are characterized by a low r2/r1 ratio of 4.9 at 1.5 T, hence resulting in good dual T1 and T2 contrast agents under low magnetic fields, whereas the 14 nm MNPs behave as excellent T2 contrast agents under high magnetic fields (r2 = 335.6 mM-1 s-1). The polymer core shell of the PEGylated MNPs minimizes their cytotoxicity, and allows long blood circulation times. This combination of cellular compatibility and excellent T2 and r2/r1 values under low magnetic fields, together with long circulation times, make these nanomaterials very promising contrast agents for molecular imaging.Magnetic resonance based molecular imaging has emerged as a very promising technique for early detection and treatment of a wide variety of diseases, including cancer, neurodegenerative disorders, and vascular diseases. The limited sensitivity and specificity of conventional MRI are being overcome by the development of a new generation of contrast agents, using nanotechnology approaches, with improved magnetic and biological properties. In particular, for molecular imaging, high specificity, high sensitivity, and long blood circulation times are required. Furthermore, the lack of toxicity and immunogenicity together with low-cost scalable production are also necessary to get them into the clinics. In this work, we describe a facile, robust and cost-effective ligand-exchange method to synthesize dual T1 and T2 MRI contrast agents with long circulation times. These contrast agents are based on manganese ferrite nanoparticles (MNPs) between 6 and 14 nm in size covered by a 3 kDa polyethylene glycol (PEG) shell that leads to a great stability in aqueous media with high crystallinity and magnetization values, thus retaining the magnetic properties of the uncovered MNPs. Moreover, the PEGylated MNPs have shown different relaxivities depending on their size and the magnetic field applied. Thus, the 6 nm PEGylated MNPs are characterized by a low r2/r1 ratio of 4.9 at 1.5 T, hence resulting in good dual T1 and T2 contrast agents under low magnetic fields, whereas the 14 nm MNPs behave as excellent T2 contrast agents under high magnetic fields (r2 = 335.6 mM-1 s-1). The polymer core shell of the PEGylated MNPs minimizes their cytotoxicity, and allows long blood circulation times. This combination of cellular compatibility and excellent T2 and r2/r1 values under low magnetic fields, together with long circulation times, make these nanomaterials very promising contrast agents for molecular imaging. Electronic supplementary information (ESI) available: Additional experimental details including TEM images of MNPs, size distribution graphs, thermogravimetric curves, FTIR spectra, and XRD patterns of MNPs. See DOI: 10.1039/c4nr05781c

Pernia Leal, Manuel; Rivera-Fernández, Sara; Franco, Jaime M.; Pozo, David; de La Fuente, Jesús M.; García-Martín, María Luisa

2015-01-01

218

Preparation of metallic nanoparticles by irradiation in starch aqueous solution  

NASA Astrophysics Data System (ADS)

Colloidal silver nanoparticles (AgNPs) were synthesized in a single step by electron beam irradiation reduction of silver ions in aqueous solution containing starch. The nanoparticles were characterized by spectrophotocolorimetry and compared with those obtained by chemical (thermal) reduction method. The results showed that the smaller sizes of AgNPs were prepared with higher yields as the irradiation dose increased. The broadening of particle size distribution occurred by increasing of irradiation dose and dose rate. Chromatic parameters such as b* (yellow-blue coordinate), C* (chroma) and ?Eab (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle ho was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.

Nemţanu, Monica R.; Bra?oveanu, Mirela; Iacob, Nicu?or

2014-11-01

219

Preparation of Mg and Al phosphate coatings on ferritic steel by wet-chemical method as tritium permeation barrier  

Microsoft Academic Search

Layers of Mg or Al phosphate were prepared on type 430 ferritic stainless steel (SS430) by wet-chemical methods as tritium permeation barrier. Disk-type specimens of SS430 were first coated with ZrO2\\/ZrO2 or ZrO2\\/Al2O3 layers (100nm) by sol–gel and electrolytic deposition techniques. Then, the phosphate layers were prepared by dip-coating method; the total thickness of coating was 200nm. The permeation rate

Kun Zhang; Yuji Hatano

2010-01-01

220

Enhancement of the physical properties of rare-earth-substituted Mn–Zn ferrites prepared by flash method  

Microsoft Academic Search

The effect of rare-earth ions on the structural, magnetic and electrical properties of rare-earth-doped manganese–zinc ferrite is reported. The compounds with the formula Mn0.5Zn0.5R0.05Fe1.95O4 where R=Tb, La, Ce and Th, were prepared by the flash combustion technique. The prepared samples reveal that by introducing a relatively small amount of R(NO3)3 or R(Cl3) instead of Fe2O3, an important modification of both

M. A. Ahmed; N. Okasha; M. M. El-Sayed

2007-01-01

221

Synthesis and magnetic properties of CoFe{sub 2}O{sub 4} spinel ferrite nanoparticles doped with lanthanide ions  

SciTech Connect

Lanthanide ions have been doped into cobalt spinel ferrites using an oil-in-water micellar method to form CoLn{sub 0.12}Fe{sub 1.88}O{sub 4} nanoparticles with Ln=Ce, Sm, Eu, Gd, Dy, or Er. Doping with lanthanide ions (Ln{sup III}) modulates the magnetic properties of cobalt spinel ferrite nanoparticles. In particular cases of Gd{sup 3+} or Dy{sup 3+} ions, a dramatic increase in the blocking temperature and coercivity is observed. Indeed, the introduction of only 4% of Gd{sup 3+} ions increases the blocking temperature {similar_to}100 K and the coercivity 60%. Initial studies on the magnetic properties of these doped nanoparticles clearly demonstrate that the relationship between the modulation of magnetic properties and the nature of doped Ln{sup III} ions is interesting but very complex. {copyright} 2001 American Institute of Physics.

Kahn, Myrtil L.; Zhang, Z. John

2001-06-04

222

Magnetic and dielectric interactions in nano zinc ferrite powder: Prepared by self-sustainable propellant chemistry technique  

NASA Astrophysics Data System (ADS)

The structural, magnetic and dielectric properties of nano zinc ferrite prepared by the propellant chemistry technique are studied. The PXRD measurement at room temperature reveal that the compound is in cubic spinel phase, belong to the space group Fd-3m. The unit cell parameters have been estimated from Rietveld refinement. The calculated force constants from FTIR spectrum corresponding to octahedral and tetrahedral sites at 375 and 542 cm-1 are 6.61×102 and 3.77×102 N m-1 respectively; these values are slightly higher compared to the other ferrite systems. Magnetic hysteresis and EPR spectra show superparamagnetic property nearly to room temperature due to comparison values between magnetic anisotropy energy and the thermal energy. The calculated values of saturation magnetization, remenant magnetization, coercive field and magnetic moment supports for the existence of multi domain particles in the sample. The temperature dependent magnetic field shows the spin freezing state at 30 K and the blocking temperature at above room temperature. The frequency dependent dielectric interactions show the variation of dielectric constant, dielectric loss and impedance as similar to other ferrite systems. The AC conductivity in the prepared sample is due to the presence of electrons, holes and polarons. The synthesized material is suitable for nano-electronics and biomedical applications.

Daruka Prasad, B.; Nagabhushana, H.; Thyagarajan, K.; Nagabhushana, B. M.; Jnaneshwara, D. M.; Sharma, S. C.; Shivakumara, C.; Gopal, N. O.; Ke, Shyue-Chu; Chakradhar, R. P. S.

2014-05-01

223

The microstructure and characteristics of magnetite thin films prepared by ultrasound-enhanced ferrite plating  

Microsoft Academic Search

Magnetite thin films were produced using the ultrasound-enhanced ferrite plating method. The effect of ferrite plating conditions on the microstructure and magnetic properties was investigated. The saturation magnetization (Ms) and the coercive force (Hc) of the magnetic thin films were 465-475 emu\\/cm3 and 60-65 Oe, respectively. Then, the applicability of the magnetite thin films as a CO gas sensor was

Chun-Young Oh; Jae-Hee Oh; Taegyung Ko

2002-01-01

224

Manganese ferrite nanoparticle micellar nanocomposites as MRI contrast agent for liver imaging  

Microsoft Academic Search

Iron oxide nanoparticles are effective contrast agents for enhancement of magnetic resonance imaging at tissue, cellular or even molecular levels. In this study, manganese doped superparamagnetic iron oxide (Mn-SPIO) nanoparticles were used to form ultrasensitive MRI contrast agents for liver imaging. Hydrophobic Mn-SPIO nanoparticles are synthesized in organic phase and then transferred into water with the help of block copolymer

Jian Lu; Shuli Ma; Jiayu Sun; Chunchao Xia; Chen Liu; Zhiyong Wang; Xuna Zhao; Fabao Gao; Qiyong Gong; Bin Song; Xintao Shuai; Hua Ai; Zhongwei Gu

2009-01-01

225

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles  

PubMed Central

Summary Monatomic (Fe, Co) and bimetallic (FePt and CoPt) nanoparticles were prepared by exploiting the self-organization of precursor loaded reverse micelles. Achievements and limitations of the preparation approach are critically discussed. We show that self-assembled metallic nanoparticles can be prepared with diameters d = 2–12 nm and interparticle distances D = 20–140 nm on various substrates. Structural, electronic and magnetic properties of the particle arrays were characterized by several techniques to give a comprehensive view of the high quality of the method. For Co nanoparticles, it is demonstrated that magnetostatic interactions can be neglected for distances which are at least 6 times larger than the particle diameter. Focus is placed on FePt alloy nanoparticles which show a huge magnetic anisotropy in the L10 phase, however, this is still less by a factor of 3–4 when compared to the anisotropy of the bulk counterpart. A similar observation was also found for CoPt nanoparticles (NPs). These results are related to imperfect crystal structures as revealed by HRTEM as well as to compositional distributions of the prepared particles. Interestingly, the results demonstrate that the averaged effective magnetic anisotropy of FePt nanoparticles does not strongly depend on size. Consequently, magnetization stability should scale linearly with the volume of the NPs and give rise to a critical value for stability at ambient temperature. Indeed, for diameters above 6 nm such stability is observed for the current FePt and CoPt NPs. Finally, the long-term conservation of nanoparticles by Au photoseeding is presented. PMID:21977392

Han, Luyang; Biskupek, Johannes; Kaiser, Ute; Ziemann, Paul

2010-01-01

226

High frequency magneto-dielectric effects in self-assembled ferrite-ferroelectric core-shell nanoparticles  

NASA Astrophysics Data System (ADS)

Magneto-dielectric effects in self-assembled core-shell nanoparticles of nickel ferrite (NFO) and barium titanate (BTO) have been investigated in the millimeter wave frequencies. The core-shell nano-composites were synthesized by coating 100 nm nickel ferrite and 50 nm barium titanate nanoparticles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst forming heterogeneous nanocomposites. Magneto-electric (ME) characterization of as-assembled particles has been carried out by measurements of the relative permittivity ?r as a function of frequency f under an applied static magnetic field H over 16-24 GHz. Measurements show an H-induced decrease in ?r of 1 to 1.5%. But a giant magneto-dielectric effect with an H-induced change in permittivity as high as 28% is measured under dielectric resonance in the samples. A strong ME coupling was also evident from H-tuning of dielectric resonance in the composites. A theory for the high frequency magneto-dielectric effect has been developed and consists of the following steps. First the Bruggeman model is used to estimate the effective dielectric constant for the shell consisting of the BTO particles and voids considered as spherical air-pores. Then the permittivity for the core and shell is estimated taking into consideration the sample porosity. Finally the H-dependence of the permittivity due to ME interactions is calculated from the free energy considerations. Estimated ?r vs. H and dielectric resonance frequency vs. H characteristics are in general agreement with the data.

Popov, M.; Sreenivasulu, G.; Petrov, V. M.; Chavez, F. A.; Srinivasan, G.

2014-09-01

227

Nanostructured bismuth ferrites synthesized by solvothermal process  

Microsoft Academic Search

Well-crystallized bismuth ferrite nanoparticles were synthesized using the solvothermal method without the help of any mineralizer. The shape of the particles was changed by changing the synthesis temperature during solvothermal process. The as-prepared samples were characterized by an X-ray powder diffractometer (XRD), scanning electron microscope (SEM), thermal analyzer and vibrating sample magnetometer (VSM). It was observed that the change in

A. Chaudhuri; S. Mitra; M. Mandal; K. Mandal

2010-01-01

228

Zinc ferrite nanoparticles as MRI contrast agentsw Carlos Ba rcena,a  

E-print Network

-invasive diagnosis and post- therapy assessment of a variety of diseases. MRI contrast can be enhanced by the use.e., Mn2+ occupies both A and B sites), whereas the other metal ferrites have an inverse spinel structure Administration has set the reference daily intake (RDI) doses for Fe and Zn at 18 and 15 mg/day, respectively

Gao, Jinming

229

Structure and magnetic properties of rf thermally plasma synthesized Mn and MnZn ferrite nanoparticles  

E-print Network

Structure and magnetic properties of rf thermally plasma synthesized Mn and Mn­Zn ferrite, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 Presented on 13 November 2002 Plasma synthesisW­3 MHz rf radio frequency induction plasma torch. We investigate these materials for soft magnetic

McHenry, Michael E.

230

Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles  

NASA Astrophysics Data System (ADS)

A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

2014-06-01

231

Visualization of internalization of functionalized cobalt ferrite nanoparticles and their intracellular fate.  

PubMed

In recent years, nanoparticles (NPs) and related applications have become an intensive area of research, especially in the biotechnological and biomedical fields, with magnetic NPs being one of the promising tools for tumor treatment and as MRI-contrast enhancers. Several internalization and cytotoxicity studies have been performed, but there are still many unanswered questions concerning NP interactions with cells and NP stability. In this study, we prepared functionalized magnetic NPs coated with polyacrylic acid, which were stable in physiological conditions and which were also nontoxic short-term. Using fluorescence, scanning, and transmission electron microscopy, we were able to observe and determine the internalization pathways of polyacrylic acid-coated NPs in Chinese hamster ovary cells. With scanning electron microscopy we captured what might be the first step of NPs internalization - an endocytic vesicle in the process of formation enclosing NPs bound to the membrane. With fluorescence microscopy we observed that NP aggregates were rapidly internalized, in a time-dependent manner, via macropinocytosis and clathrin-mediated endocytosis. Inside the cytoplasm, aggregated NPs were found enclosed in acidified vesicles accumulated in the perinuclear region 1 hour after exposure, where they stayed for up to 24 hours. High intracellular loading of NPs in the Chinese hamster ovary cells was obtained after 24 hours, with no observable toxic effects. Thus polyacrylic acid-coated NPs have potential for use in biotechnological and biomedical applications. PMID:23486857

Bregar, Vladimir B; Lojk, Jasna; Suštar, Vid; Verani?, Peter; Pavlin, Mojca

2013-01-01

232

Copper(0) nanoparticles supported on silica-coated cobalt ferrite magnetic particles: cost effective catalyst in the hydrolysis of ammonia-borane with an exceptional reusability performance.  

PubMed

Herein we report the development of a new and cost-effective nanocomposite catalyst for the hydrolysis of ammonia-borane (NH(3)BH(3)), which is considered to be one of the most promising solid hydrogen carriers because of its high gravimetric hydrogen storage capacity (19.6% wt) and low molecular weight. The new catalyst system consisting of copper nanoparticles supported on magnetic SiO(2)/CoFe(2)O(4) particles was reproducibly prepared by wet-impregnation of Cu(II) ions on SiO(2)/CoFe(2)O(4) followed by in situ reduction of the Cu(II) ions on the surface of magnetic support during the hydrolysis of NH(3)BH(3) and characterized by ICP-MS, XRD, XPS, TEM, HR-TEM and N(2) adsorption-desorption technique. Copper nanoparticles supported on silica coated cobalt(II) ferrite SiO(2)/CoFe(2)O(4) (CuNPs@SCF) act as highly active catalyst in the hydrolysis of ammonia-borane, providing an initial turnover frequency of TOF = 2400 h(-1) at room temperature, which is not only higher than all the non-noble metal catalysts but also higher than the majority of the noble metal based homogeneous and heterogeneous catalysts employed in the same reaction. More importantly, they were easily recovered by using a permanent magnet in the reactor wall and reused for up to 10 recycles without losing their inherent catalytic activity significantly, which demonstrates the exceptional reusability of the CuNPs@SCF catalyst. PMID:22856878

Kaya, Murat; Zahmakiran, Mehmet; Ozkar, Saim; Volkan, Mürvet

2012-08-01

233

Preparation and Characterization of Nano-particle Substituted Barium Hexaferrite  

E-print Network

High density magnetic recording requires high coercivity magnetic media and small particle size. Barium hexaferrite has been considered as a leading candidate material because of its chemical stability, fairly large crystal anisotropy and suitable magnetic characteristics. In this work, we present the preparation of the hexagonal ferrite BaFe12O19 and one of its derivative; the Zn-Sn substituted hexaferrite by the chemical co-precipitation method. The main advantage of this method on the conventional glass-ceramic one, resides in providing a small enough particle size for magnetic recording. We demonstrate using the X-ray diffraction patterns that the particle size decreases when substituting the hexaferrite by the Zn-Sn combination. This may improve the magnetic properties of the hexaferrite as a medium for HD magnetic recording

Atassi, Yomen; Tally, Mohammad

2014-01-01

234

Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys  

DOEpatents

In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

2012-07-03

235

Magnetic nanoparticles: preparation, physical properties, and applications in biomedicine  

PubMed Central

Finally, we have addressed some relevant findings on the importance of having well-defined synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the preparation of monodisperse samples of relatively large quantities not only with similar physical features, but also with similar crystallochemical characteristics. Then, different methodologies for the functionalization of the prepared MNPs together with the characterization techniques are explained. Theorical views on the magnetism of nanoparticles are considered. PMID:22348683

2012-01-01

236

Non-toxic nanoparticles from phytochemicals: preparation and biomedical application.  

PubMed

Nanoparticles (NPs) have various applications in biomedicine and drug delivery carriers and also are widely used in cosmetics. However, the preparation of biocompatible and non-toxic nanomaterials is a very important issue as most of the starting materials are synthesized using toxic chemical reagents. This review introduces the preparation of biocompatible NPs in a range of their concentrations using phytochemicals for biomedicine and biotechnology. Phytochemicals are natural products that are extracted from plants, vegetables, and fruits. Phytochemicals serve as reducing agents and stabilizers during NP synthesis to convert metal ions to metal NPs in water. Possible applications of such nanomaterials in biomedical sciences are also described in this review. PMID:24263370

Lee, Jaewook; Park, Enoch Y; Lee, Jaebeom

2014-06-01

237

Comparative study on the preparation of conductive copper pastes with copper nanoparticles prepared by electron beam irradiation and chemical reduction  

NASA Astrophysics Data System (ADS)

Copper nanoparticles with narrow size distribution of 5-7 nm were synthesized by using electron beam irradiation. The copper nanoparticles were stable in ambient air for two months. TGA showed that the copper nanoparticles prepared by using electron beam irradiation have the higher wt% of pure copper metal compared with the one prepared by chemical reduction using hydrazine hydrate(N 2H 4· xH 2O). The conductive copper paste with copper nanoparticles prepared by electron beam irradiation showed higher conductivity than the paste with copper nanoparticles prepared by chemical reduction with N 2H 4 due to small size, less amount of surfactants on the surface and higher stability against the oxidation in ambient condition. The highest conductivity of copper paste was determined as 170 S cm -1 at 90 wt% of copper nanoparticles in the paste.

Pham, Long Quoc; Sohn, Jong Hwa; Park, Ji Hyun; Kang, Hyun Suk; Lee, Byung Cheol; Kang, Young Soo

2011-05-01

238

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles  

PubMed Central

Summary Organic–inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with ?-cyclodextrin (Fe-Ni/Zn/?CD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr3+ and Cr2O7 2? ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/?CD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer–Emmett–Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of ?CD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with ?CD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/?CD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn. PMID:23209524

Denadai, Ângelo M L; De Sousa, Frederico B; Passos, Joel J; Guatimosim, Fernando C; Barbosa, Kirla D; Burgos, Ana E; de Oliveira, Fernando Castro; da Silva, Jeann C; Neves, Bernardo R A; Mohallem, Nelcy D S

2012-01-01

239

Effects of Thermal Annealing on Structural and Magnetic Properties of Lithium Ferrite Nanoparticles  

Microsoft Academic Search

Pure, crystalline, 10 nm lithium ferrite phase (Li{sub 0.5}Fe{sub 2.5}O), was successfully synthesized at very low temperature using a modified combustion method. The crystal structure and microstructure evolution of this system upon annealing were monitored by a careful investigation of X-ray diffractograms collected on a synchrotron source. Comparative analysis of the results obtained from the full profile Rietveld method (in

Natas?a G. Jovic?; Ahmad S. Masadeh; Aleksandar S. Kremenovic?; Bratislav V. Antic?; Jovan L. Blanusa; Nikola D. Cvjeticanin; Gerardo F. Goya; Marco Vittori Antisari; Emil S. Bozin

2010-01-01

240

Preparation of poly(lactic acid)\\/chitosan nanoparticles for anti-HIV drug delivery applications  

Microsoft Academic Search

Poly(lactic acid) (PLA)\\/chitosan (CS) nanoparticles were prepared by emulsion method for anti-HIV drug delivery applications. The prepared PLA\\/CS nanoparticles were characterized using DLS, SEM, and FTIR. The hydrophilic antiretroviral drug Lamivudine was loaded into PLA\\/CS nanoparticles. The encapsulation efficiency and in-vitro drug release behaviour of drug loaded PLA\\/CS nanoparticles were studied using UV spectrophotometer. In addition, the cytotoxicity of the

Ashish Dev; N. S. Binulal; A. Anitha; S. V. Nair; T. Furuike; H. Tamura; R. Jayakumar

2010-01-01

241

Effects of MnO 2 on the electromagnetic properties of NiCuZn ferrites prepared by sol-gel auto-combustion  

NASA Astrophysics Data System (ADS)

Mn-doped NiCuZn ferrites with compositions of (Ni 0.2Cu 0.2Zn 0.6)O(Fe 2- x,Mn xO 3) 0.98 ( x=0, 0.02, 0.04, 0.06) were prepared by a novel sol-gel auto-combustion process. The synthesized nano-sized ferrite powders can be sintered at 900°C, and the sintered ferrites are characterized by fine-grained microstructural feature and high permeability. Mn content in formulations largely affects the grain size and main electromagnetic properties of sintered NiCuZn ferrites. With increasing Mn content, the initial permeability is significantly increased, while the electrical resistivity and quality factor are decreased. The dielectric constant and dissipation factor are also affected by the incorporation of MnO 2. The possible mechanism for the influence of MnO 2 on the electromagnetic properties was discussed.

Yue, Zhenxing; Zhou, Ji; Li, Longtu; Gui, Zhilun

2001-08-01

242

Preparation of size-controlled tungsten oxide nanoparticles and evaluation of their adsorption performance  

SciTech Connect

The present study investigated the effects of particle size on the adsorption performance of tungsten oxide nanoparticles. Nanoparticles 18-73 nm in diameter were prepared by evaporation of bulk tungsten oxide particles using a flame spray process. Annealing plasma-made tungsten oxide nanoparticles produced particles with diameters of 7-19 nm. The mechanism of nanoparticle formation for each synthetic route was examined. The low-cost, solid-fed flame process readily produced highly crystalline tungsten oxide nanoparticles with controllable size and a remarkably high adsorption capability. These nanoparticles are comparable to those prepared using the more expensive plasma process.

Hidayat, Darmawan [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)] [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Purwanto, Agus [Department of Chemical Engineering, Faculty of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta, Central Java 57126 (Indonesia)] [Department of Chemical Engineering, Faculty of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta, Central Java 57126 (Indonesia); Wang, Wei-Ning [Department of Energy, Environmental and Chemical Engineering, School of Engineering and Applied Science, Washington University in St. Louis, St. Louis, MO 63130 (United States)] [Department of Energy, Environmental and Chemical Engineering, School of Engineering and Applied Science, Washington University in St. Louis, St. Louis, MO 63130 (United States); Okuyama, Kikuo, E-mail: okuyama@hiroshima-u.ac.jp [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)] [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan)

2010-02-15

243

Preparation and applications of ZnSe nanoparticles  

NASA Astrophysics Data System (ADS)

Semiconductor nanoparticles have been attracting widespread scientific and technological interest due to their unique size-tunable optical and electronic properties. The ZnSe nanoparticles have wide-ranging applications in laser, optical instruments, etc. because it has a wide band gap and transmittance range, high luminescence efficiency, low absorption coefficient, and excellent transparency to infrared. ZnSe nanoparticles have been prepared at room temperature. Zinc chloride 99 mM of 4 mL is added to 2.2g PVA. Volume of the solution is made up to 50 mL by bidistilled water. The Solution is left for 24 h at room temperature to swell. After that the solution is warmed up to 60°C and stirred for 4 h until viscous transparent solution was obtained. One milliliter of Sodium Hydrogen Selenide was dropped into the solution with gentle stirring. Solution is casted on flat glass plate dishes. After the solvent evaporation, a thin film containing ZnSe nanoparticles are obtained. The film is washed with de-ionized water to remove other soluble salts before measurements.

Ravindranadh, K.; Shekhawat, M. S.; Rao, M. C.

2013-06-01

244

Size tuned electrophoretic pyrazoline nanoparticles prepared through dispersion-polymerization.  

PubMed

Highly monodispersed electrophoretic particles of size ranging from 550 to 160 nm could be prepared through dispersion-polymerization of methyl methacrylate and ethylene glycol dimethacrylate in presence of pyrazoline nanoparticles in a methanol-water mixture. The size of the fabricated electrophoretic particles could be controlled by adjusting the concentration of surfactant. Stearic acid, used as surfactant during the polymerization process also acts as charge controlling additive to control the electrophoric mobility of the particles. Maximum electrophoric mobility (-7.513×10(-5) cm(2)/Vs) was obtained for the 400 nm electrophoretic particles prepared with 1.5 wt.% of stearic acid surfactant. The electrophoric display cells prepared with our electrophoretic particles reveal good current voltage characteristics and color change under applied bias voltage. PMID:21333301

Oh, Sun Wha; Kim, Chang Woo; Son, Se-Mo; Kang, Young Soo

2011-05-01

245

Effect of filler loading of nickel zinc ferrite on the tensile properties of PLA nanocomposites  

NASA Astrophysics Data System (ADS)

The mechanical strength of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with polylactic acid (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90:10. The MPNC were prepared at constant mixing temperature at 180°C, mixing time of 15 min. and mixing speed of 100 rpm. In order to achieve a good dispersion of NiZn ferrite in the matrix, firstly an ultrasonic treatment had been employed to mix the LNR and NiZn ferrite for 1 hour. The MPNC of PLA/LNR/NiZn ferrite then were prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1-5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases the tensile strength also increases until an optimum value of filler loading was reached. The Young's modulus, tensile strength and elongation at break have also increased. The study proves that NiZn ferrite is excellent reinforcement filler in PLA matrix. Scanning electron micrograph (SEM) and energy dispersive X-ray spectroscopy (EDX) were meant to show the homogeneity dispersion of nanoparticles within the matrix and to confirm the elemental composition of NiZn ferrites-PLA/LNR nanocomposites respectively.

Shahdan, Dalila; Ahmad, Sahrim Hj

2013-05-01

246

Preparation and Properties of FeCo Nanoparticles  

SciTech Connect

Fe-Co nanoparticles were prepared from the binary Fe-Co oxalate. The formation of FeCo metallic phase begun at 290 deg. C as determined from the X-ray diffraction patterns recorded during heating of the oxalate sample in hydrogen atmosphere. The reduction finished at 500 deg. C by formation of bcc FeCo phase with a mean particle size of about 50 nm. Analysis of the Moessbauer spectra shows that the ferromagnetic FeCo phase is represented by two sextets corresponding to interiors and surfaces of the nanoparticles. In addition, a weak paramagnetic component, represented by the doublet, was observed which was ascribed to fine particles in a superparamagnetic state. TEM images have shown conglomerates of particles with the composition of about 50 at. % Fe and 50 at. % Co.

Zabransky, K.; David, B.; Pizurova, N.; Schneeweiss, O. [Institute of Physics of Materials, Academy of Sciences of Czech Republic, v.v.i., Zizkova 22, 61662 Brno (Czech Republic); Zboril, R.; Maslan, M. [Centre for Nanomaterial Research, Faculty of Science, Palacky University, 17. listopadu 1192/12, 771 46 Olomouc (Czech Republic)

2010-07-13

247

Preparation and characterization of magnetic nanoparticles coated with polyethylene glycol  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles Fe3O4 were prepared in air environment by the coprecipitation method using molar ratios of Fe2+: Fe3+ = 1: 2. The surface of magnetic nanoparticles was coated with sodium oleate as the primary layer and polyethylene glycol 6000 (PEG-6000) as the second layer. The morphology of the particles was investigated by scanning electronic microscopy (SEM). X-ray diffraction (XRD) indicated the sole existence of inverse cubic spinel phase of Fe3O4 and an average size of about 25 nm. Fourier transform infrared spectroscopy (FTIR) analysis indicated existence of two distinct surfactants on the particle surface. In addition, the results of FT-IR indicated that the coated Fe3O4 particles improved the thermal stability due to the interaction between the Fe3O4 particles and protective layers.

Hoa, Le Thi Mai; Thi Dung, Tran; Mau Danh, Tran; Duc, Nguyen Huu; Mau Chien, Dang

2009-09-01

248

Preparation of cobalt-zinc ferrite (Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) nanopowder via combustion method and investigation of its magnetic properties  

SciTech Connect

Research highlights: {yields} Cobalt-zinc ferrite was prepared by combustion method. {yields} Properties of the sample were characterized by several techniques. {yields} Curie temperature was determined to be 350 {sup o}C. -- Abstract: Cobalt-zinc ferrite (Co{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4}) was prepared by combustion method, using cobalt, zinc and iron nitrates. The crystallinity of the as-burnt powder was developed by annealing at 700 {sup o}C. Crystalline phase was investigated by XRD. Using Williamson-Hall method, the average crystallite sizes for nanoparticles were determined to be about 27 nm before and 37 nm after annealing, and residual stresses for annealed particles were omitted. The morphology of the annealed sample was investigated by TEM and the mean particle size was determined to be about 30 nm. The final stoichiometry of the sample after annealing showed good agreement with the initial stoichiometry using atomic absorption spectrometry. Magnetic properties of the annealed sample such as saturation magnetization, remanence magnetization, and coercivity measured at room temperature were 70 emu/g, 14 emu/g, and 270 Oe, respectively. The Curie temperature of the sample was determined to be 350 {sup o}C using AC-susceptibility technique.

Yousefi, M.H. [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of)] [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of); Manouchehri, S., E-mail: dez283@yahoo.com [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of); Department of Physics, Faculty of Science, The University of Isfahan, Esfahan 81746-73441 (Iran, Islamic Republic of); Arab, A. [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of)] [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of); Mozaffari, M. [Department of Physics, Faculty of Science, The University of Isfahan, Esfahan 81746-73441 (Iran, Islamic Republic of) [Department of Physics, Faculty of Science, The University of Isfahan, Esfahan 81746-73441 (Iran, Islamic Republic of); Physics Department, Razi University, Taghbostah, Kermanshah (Iran, Islamic Republic of); Amiri, Gh. R. [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of) [Department of Physics, Malek-Ashtar University of Technology, Shahinshahr, 83145-34177 (Iran, Islamic Republic of); Department of Plasma Physics, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Amighian, J. [Islamic Azad University, Najafabad Branch, Najafabad (Iran, Islamic Republic of)] [Islamic Azad University, Najafabad Branch, Najafabad (Iran, Islamic Republic of)

2010-12-15

249

High magnetostriction and coupling coefficient for sintered cobalt ferrite derived from superparamagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

High magnetostriction (?) and coupling coefficient (d? /dH) of 315 ppm and 1.97×10-9 A-1m, respectively, are obtained at room temperature for sintered cobalt ferrite derived from nanocrystalline powders. Also, the powder was compacted at a low pressure of 8 MPa and sintered for a short duration of 10 min at 1450 °C. Magnetic annealing at 300 °C in a field of 0.5 T for 30 min further enhanced the magnetostriction coefficient to 345 ppm with a higher coupling coefficient 2.12×10-9 A-1m. The magnetic field above which maximum magnetostriction is observed is reduced by almost half after magnetic annealing.

Khaja Mohaideen, K.; Joy, P. A.

2012-08-01

250

Magnetite coating prepared by ferrite plating on expanded polytetrafluoroethylene membrane for medical use  

NASA Astrophysics Data System (ADS)

As the first step to the study of increasing biocompatibility of expanded polytetrafluoroethylene (EPTFE) membranes, cardiovascular patches of EPTFE substrates were coated with Fe3O4 layer, which is expected to accelerate proliferation of endothelial cells. The ferrite layers were formed by the thin liquid film ferrite plating method at T=75-90 °C and pH (in oxidizing solution)=6.9-7.4. At a fixed pH value, a single-phase Fe3O4 layer is obtained when T is higher than a threshold temperature, which increases with an increasing pH value; below the threshold temperature, the layer has an impurity phase of ?-FeOOH. The obtained Fe3O4 layers are polycrystalline with no preferred orientation, having magnetization and coercive force which agree with those reported for bulk samples.

Zhang, Q.; Itoh, T.; Abe, M.

1994-05-01

251

Structural, magnetic and electrical properties of cobalt ferrites prepared by the sol–gel route  

Microsoft Academic Search

Nanosized cobalt ferrites having the general formula CoFe2?xAlxO4 (for x=0.00, 0.25, 0.50) have been synthesized by the sol–gel route. The effect of Al3+ ions on structural, Curie temperature, DC electrical resistivity and dielecltric properties are presented in this paper. From the analysis of powder X-ray diffraction patterns, the nanocrystallite size was calculated by the most intense peak (311) using Scherrer

I. H. Gul; A. Maqsood

2008-01-01

252

Thermally activated crystalline phase restoration in disordered barium ferrite powder prepared by ball milling  

Microsoft Academic Search

Depending on milling conditions (air or vacuum) for the same milling time, a different level of decomposition and structure disorder in BaFe12O19 ferrite powders can be obtained by ball milling. Air-milled material has a tendency to form a gas-saturated disordered structure (superoxide) and to transform into simple oxides (reduction process through oxygen-saturated disordered phase) as opposed to the vacuum-milled powder

W. A. Kaczmiarek; Z. L. Li

1996-01-01

253

The structural and magnetic properties of barium ferrite powders prepared by the sol—gel method  

Microsoft Academic Search

In this paper, M-type hexagonal barium ferrite powders are synthesized using the sol—gel method. A dried precursor heated in air is analyzed in the temperature range from 50 to 1200 °C using thermo-gravimetric analysis and differential scanning calorimetry. The effects of the additives and the cacinating temperature on the magnetic properties are investigated, and the results show that single-phase barium

Li Jie; Zhang Huai-Wu; Li Yuan-Xun; Liu Ying-Li; Ma Yan-Bing

2012-01-01

254

Nickel-doped cobalt ferrite nanoparticles: efficient catalysts for the reduction of nitroaromatic compounds and photo-oxidative degradation of toxic dyes.  

PubMed

This study deals with the exploration of NixCo?-xFe?O? (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) ferrite nanoparticles as catalysts for reduction of 4-nitrophenol and photo-oxidative degradation of Rhodamine B. The ferrite samples with uniform size distribution were synthesized using the reverse micelle technique. The structural investigation was performed using powder X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray and scanning tunneling microscopy. The spherical particles with ordered cubic spinel structure were found to have the crystallite size of 4-6 nm. Diffused UV-visible reflectance spectroscopy was employed to investigate the optical properties of the synthesized ferrite nanoparticles. The surface area calculated using BET method was found to be highest for Co?.?Ni?.?Fe?O? (154.02 m(2) g(-1)). Co?.?Ni?.?Fe?O? showed the best catalytic activity for reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 as reducing agent, whereas CoFe?O? was found to be catalytically inactive. The reduction reaction followed pseudo-first order kinetics. The effect of varying the concentration of catalyst and NaBH? on the reaction rates was also scrutinized. The photo-oxidative degradation of Rhodamine B, enhanced oxidation efficacy was observed with the introduction of Ni(2+) in to the cobalt ferrite lattice due to octahedral site preference of Ni(2+). Almost 99% degradation was achieved in 20 min using NiFe?O? nanoparticles as catalyst. PMID:24902783

Singh, Charanjit; Goyal, Ankita; Singhal, Sonal

2014-07-21

255

Magnetic properties of nanosized Gd doped Ni-Mn-Cr ferrites prepared using the sol-gel autocombustion technique  

NASA Astrophysics Data System (ADS)

Ni0.8Mn0.2Cr0.5Fe1.5-xGdxO4 (where x=0, 0.02, 0.04, 0.06, 0.08) spinel ferrites were synthesized by a sol-gel autocombustion technique using citric acid as fuel. Effect of Gd doping on structural and magnetic properties of Ni-Mn-Cr ferrites is reported. The phase composition of the prepared samples was analyzed by X-ray diffraction and Fourier transform infrared spectroscopy, and the magnetic measurements were realized using a vibrating sample magnetometer. XRD and FT-IR analysis reveal pure spinel phase in all the samples, without traces of secondary phases. The grain sizes were estimated from the TEM micrographs and were found to decrease with the doping ions concentration from 43 to 10 nm. It was revealed from the hysteresis loop of the materials that magnetization and coercivity followed decreasing trend with substitution of Fe3+ magnetic ions by Gd3+ ions. Also, introducing Gd ions into the spinel lattice led to the decrease in Curie temperature.

Samoila, P.; Sacarescu, L.; Borhan, A. I.; Timpu, D.; Grigoras, M.; Lupu, N.; Zaltariov, M.; Harabagiu, V.

2015-03-01

256

Effect of retrogradation time on preparation and characterization of proso millet starch nanoparticles.  

PubMed

Starch nanoparticles were prepared from proso millet starch using a green and facile method combined with enzymolysis and recrystallization. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA) were used to characterize the morphology and crystal structure of the starch nanoparticles prepared with different retrogradation time (0.5, 4, 12, and 24h). The results showed that the sizes of the starch nanoparticles were between 20 nm and 100 nm. The crystal pattern changed from A-type (native starch) to B-type (nanoparticles), and the relative crystallinity of the nanoparticles increased obviously, as compared with the native starch. The nanoparticles prepared with the 12h retrogradation time had the highest degree of crystallinity (47.04%). Compared to conventional acid hydrolysis to make starch nanoparticles, the present approach has the advantage of being quite rapid and presenting a higher yield (about 55%). PMID:25037338

Sun, Qingjie; Gong, Min; Li, Ying; Xiong, Liu

2014-10-13

257

Experimental observations and nucleation and growth theory of polyhedral magnetic ferrite nanoparticles synthesized  

E-print Network

functionalized form). Faceted magnetite nanoparticles (Fig. 1) have been observed in magnetotactic bacteria [10 in the magnetotactic bacteria does [15]. The truncated octahedral shapes are also the most commonly occurring] and in the Martian meteorite ALH84001 [11­13]. In the magnetotactic bacte- ria, nature selects magnetite particles

McHenry, Michael E.

258

Facile preparation of silver nanoparticles immobilized on chitin nanofiber surfaces to endow antifungal activities.  

PubMed

Silver nanoparticles were prepared on chitin nanofiber surfaces by UV light reduction of silver ions. The chitin nanofibers could be efficient substrates to immobilize silver nanoparticles with stable dispersion states. The dispersion and the nanocomposite film with acrylic resin showed characteristic absorption property in the visible light region due to the effect of the silver nanoparticles. Silver nanoparticles endowed strong antifungal activity to chitin nanofibers. PMID:25498704

Ifuku, Shinsuke; Tsukiyama, Yui; Yukawa, Taisuke; Egusa, Mayumi; Kaminaka, Hironori; Izawa, Hironori; Morimoto, Minoru; Saimoto, Hiroyuki

2015-03-01

259

Luminol-silver nitrate chemiluminescence enhancement induced by cobalt ferrite nanoparticles.  

PubMed

CoFe(2)O(4) nanoparticles (NPs) could stimulate the weak chemiluminescence (CL) system of luminol and AgNO(3), resulting in a strong CL emission. The UV-visible spectra, X-ray photoelectron spectra and TEM images of the investigated system revealed that AgNO(3) was reduced by luminol to Ag in the presence of CoFe(2)O(4) NPs and the formed Ag covered the surface of CoFe(2)O(4) NPs, resulting in CoFe(2)O(4)-Ag core-shell nanoparticles. Investigation of the CL reaction kinetics demonstrated that the reaction among luminol, AgNO(3) and CoFe(2)O(4) NPs was fast at the beginning and slowed down later. The CL spectra of the luminol - AgNO(3) - CoFe(2)O(4) NPs system indicated that the luminophor was still an electronically excited 3-aminophthalate anion. A CL mechanism has been postulated. When the CoFe(2)O(4) NPs were injected into the mixture of luminol and AgNO(3), they catalyzed the reduction of AgNO(3) by luminol to produce luminol radicals and Ag, which immediately covered the CoFe(2)O(4) NPs to form CoFe(2)O(4)-Ag core-shell nanoparticles, and the luminol radicals reacted with the dissolved oxygen, leading to a strong CL emission. With the continuous deposition of Ag on the surface of CoFe(2)O(4) NPs, the catalytic activity of the core-shell nanoparticles was inhibited and a decrease in CL intensity was observed and also a slow growth of shell on the nanoparticles. PMID:21400653

Shi, Wenbing; Wang, Hui; Huang, Yuming

2011-01-01

260

Self-assembled mesoporous Co and Ni-ferrite spherical clusters consisting of spinel nanocrystals prepared using a template-free approach.  

PubMed

Based on a self-assembly strategy, spherical mesoporous cobalt and nickel ferrite nanocrystal clusters with a large surface area and narrow size distribution were successfully synthesized for the first time via a template-free solvothermal process in ethylene glycol and subsequent heat treatment. In this work, the mesopores in the ferrite clusters were derived mainly from interior voids between aggregated primary nanoparticles (with crystallite size of less than 7 nm) and disordered particle packing domains. The concentration of sodium acetate is shown herein to play a crucial role in the formation of mesoporous ferrite spherical clusters. These ferrite clusters were characterized in detail using wide-angle X-ray diffraction, thermogravimetric-differential thermal analysis, (57)Fe Mössbauer spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, standard and high-resolution transmission electron microscopy, and other techniques. The results confirmed the formation of both pure-phase ferrite clusters with highly crystalline spinel structure, uniform size (about 160 nm) and spherical morphology, and worm-like mesopore structures. The BET specific surface areas and mean pore sizes of the mesoporous Co and Ni-ferrite clusters were as high as 160 m(2) g(-1) and 182 m(2) g(-1), and 7.91 nm and 6.87 nm, respectively. A model for the formation of the spherical clusters in our system is proposed on the basis of the results. The magnetic properties of both samples were investigated at 300 K, and it was found that these materials are superparamagnetic. PMID:21904731

Yu, Byong Yong; Kwak, Seung-Yeop

2011-10-21

261

Preparation and magnetic properties of barium ferrite fine particles by the coprecipitation salt-catalysis method  

Microsoft Academic Search

The authors describe catalytic action by NaCl in the reaction between ?-Fe2O3 and BaCO3 and the development of a new process for manufacturing barium ferrite fine particles. Pure ?-FeOOH and reagent-grade BaCO3 are mixed and heated at temperatures from 300 to 800°C with and without NaCl. The BaCO3 and ?-Fe2O3 powders which are formed during heating react and change to

Hiroshi Sakai; Kenzo Hanawa; Kazumi Aoyagi

1992-01-01

262

Preparation and up-conversion luminescence of 8 nm rare-earth doped fluoride nanoparticles  

E-print Network

Preparation and up-conversion luminescence of 8 nm rare-earth doped fluoride nanoparticles V.Tikhomirov@fys.kuleuven.be, Christiane.Walrand@chem.kuleuven.be Abstract: Free-standing, 8 nm diameter, rare-earth doped nanoparticles Re10Pb25F65 have been prepared, where Re stands for either single rare-earth ion, such as Er3+ , Yb3

Moshchalkov, Victor V.

263

CO Responses of Sensors Based on Cerium Oxide Thick Films Prepared from Clustered Spherical Nanoparticles  

PubMed Central

Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors. PMID:23529123

Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

2013-01-01

264

Silver confined within zeolite EMT nanoparticles: preparation and antibacterial properties  

NASA Astrophysics Data System (ADS)

The preparation of pure zeolite nanocrystals (EMT-type framework) and their silver ion-exchanged (Ag+-EMT) and reduced silver (Ag0-EMT) forms is reported. The template-free zeolite nanocrystals are stabilized in water suspensions and used directly for silver ion-exchange and subsequent chemical reduction under microwave irradiation. The high porosity, low Si/Al ratio, high concentration of sodium and ultrasmall crystal size of the EMT-type zeolite permitted the introduction of a high amount of silver using short ion-exchange times in the range of 2-6 h. The killing efficacy of pure EMT, Ag+-EMT and Ag0-EMT against Escherichia coli was studied semi-quantitatively. The antibacterial activity increased with increasing Ag content for both types of samples (Ag+-EMT and Ag0-EMT). The Ag0-EMT samples show slightly enhanced antimicrobial efficacy compared to that of Ag+-EMT, however, the differences are not substantial and the preparation of Ag nanoparticles is not viable considering the complexity of preparation steps.The preparation of pure zeolite nanocrystals (EMT-type framework) and their silver ion-exchanged (Ag+-EMT) and reduced silver (Ag0-EMT) forms is reported. The template-free zeolite nanocrystals are stabilized in water suspensions and used directly for silver ion-exchange and subsequent chemical reduction under microwave irradiation. The high porosity, low Si/Al ratio, high concentration of sodium and ultrasmall crystal size of the EMT-type zeolite permitted the introduction of a high amount of silver using short ion-exchange times in the range of 2-6 h. The killing efficacy of pure EMT, Ag+-EMT and Ag0-EMT against Escherichia coli was studied semi-quantitatively. The antibacterial activity increased with increasing Ag content for both types of samples (Ag+-EMT and Ag0-EMT). The Ag0-EMT samples show slightly enhanced antimicrobial efficacy compared to that of Ag+-EMT, however, the differences are not substantial and the preparation of Ag nanoparticles is not viable considering the complexity of preparation steps. Electronic supplementary information (ESI) available: Zeta potential data of Ag-EMT suspensions, pore-size distributions and antibacterial data for Ag-EMT 2 h samples. See DOI: 10.1039/c4nr03169e

Dong, B.; Belkhair, S.; Zaarour, M.; Fisher, L.; Verran, J.; Tosheva, L.; Retoux, R.; Gilson, J.-P.; Mintova, S.

2014-08-01

265

Preparation of bio-compatible boron nanoparticles and novel mesoporous silica nanoparticles for bio-applications  

NASA Astrophysics Data System (ADS)

This dissertation presents the synthesis and characterization of several novel inorganic and hybrid nanoparticles, including the bio-compatible boron nanoparticles (BNPs) for boron neutron capture therapy (BNCT), tannic acid-templated mesoporous silica nanoparticles and degradable bridged silsesquioxane silica nanoparticles. Chapter 1 provides background information of BNCT and reviews the development of design and synthesizing silica nanoparticles and the study of silica material degradability. Chapter 2 describes the preparation and characterization of dopamine modified BNPs and the preliminary cell study of them. The BNPs were first produced via ball milling, with fatty acid on the surface to stabilize the combustible boron elements. This chapter will mainly focus on the ligand-exchange strategy, in which the fatty acids were replaced by non-toxic dopamines in a facile one-pot reaction. The dopamine-coated BNPs (DA-BNPs) revealed good water dispersibility and low cytotoxicity. Chapter 3 describes the synthesis of tannic acid template mesoporous silica nanoparticles (TA-TEOS SiNPs) and their application to immobilize proteins. The monodispersed TA SiNPs with uniform pore size up to approximately 13 nm were produced by utilizing tannic acid as a molecular template. We studied the influence of TA concentration and reaction time on the morphology and pore size of the particles. Furthermore, the TA-TEOS particles could subsequently be modified with amine groups allowing them to be capable of incorporating imaging ligands and other guest molecules. The ability of the TA-TEOS particles to store biomolecules was preliminarily assessed with three proteins of different charge characteristics and dimensions. The immobilization of malic dehydrogenase on TA-TEOS enhanced the stability of the enzyme at room temperature. Chapter 4 details the synthesis of several bridged silsesquioxanes and the preparation of degradable hybrid SiNPs via co-condensation of bridged silsesquioxanes with tetraethoxysilane. In vivo studies show that the solid SiNPs accumulate in many organs due to the lack of degradability. The aim of our work is to address this shortcoming by producing novel degradable SiNPs. Bridged silsesquioxanes were used as the precursors of the particles, and upon cleavage of the carbamate groups when brought into contact with aqueous media, the particles degraded into porous structures.

Gao, Zhe

266

Magnetic properties of As2O3- and Sb2O3-doped BaM hexagonal ferrites prepared by the sol-gel method  

Microsoft Academic Search

Ba-M hexagonal ferrites with As2O3 and Sb2O3 doping have been prepared in the composition series BaO.(6 - x)Fe2O3 .xM2O3 (M = As or Sb) with 0 <= x <= 0.4 by the sol-gel route. The precursor sol is prepared by using barium acetate and the chlorides of iron and arsenic\\/antimony respectively. Pellitized powders of these hexaferrites are sintered in the

P. Brahma; Anit K. Giri; D. Chakravorty; M. Roy; D. Bahadur

1992-01-01

267

Effect of light on the magnetic properties of cobalt ferrite nanoparticles  

Microsoft Academic Search

We report variations in the coercivity of CoFe2O4 nanoparticles as a function of particle size, temperature and light intensity. For 30 nm particles, this change in was 2300 Oe at 10 K, 120 Oe at 170 K, for a light intensity of under 2 milliwatts. The remanent magnetization was nearly unchanged by illumination. A simple model of optical absorption followed

Anit K. Giri; Kelly Pellerin; Wanida Pongsaksawad; Monica Sorescu; Sara A. Majetich

2000-01-01

268

Synthesis and thermal stability of polycrystalline new divalent [beta][double prime]- and [beta]-ferrites prepared by ion exchange  

SciTech Connect

Using ion-exchange chemistry the divalent cations Ba[sup 2+], Sr[sup 2+], Ca[sup 2+], Mg[sup 2+], Cd[sup 2+], Pb[sup 2+], Co[sup 2+], Zn[sup 2+], Mn[sup 2+], Fe[sup 2+], and Sn[sup 2+] have been substituted for K[sup +] in polycrystalline CdO-stabilized K-[beta][double prime]-ferrite samples. Ba, Sr, Ca, Mg, Pb, and Cd ion exchange led to the synthesis of new materials, the divalent M[sup 2+]-[beta][double prime]-ferrites (M = Ba, Sr, Ca, Mg) and M[sup 2+]-[beta]-ferrites (M = Cd, Pb), respectively. Co[sup 2+]-diffusion resulted in the formation of a spinel-type Co-ferrite. In the case of Zn, Mn, Fe, and Sn the samples decomposed to [alpha]-Fe[sub 2]O[sub 3]. The thermal stability of the new divalent [beta][double prime]- and [beta]-ferrites was studied either by high-temperature exchange reactions or by air annealing of the exchanged products. Ba- and Sr-[beta][double prime]-ferrites and Pb-[beta]-ferrite converted to M-type hexagonal ferrites with the magnetoplumbite structure, Mg-[beta][double prime]-ferrite decomposed to a spinel-type Mg-ferrite, and Ca-[beta][double prime]-ferrite and Cd-[beta]-ferrite decomposed to [alpha]-Fe[sub 2]O[sub 3]. Composition, lattice parameters, SEM photographs, and magnetic properties of the ferrites formed are given. The magnetic susceptibilities of the divalent [beta][double prime]- or [beta]-ferrites have values between 0.63 and 1.14 [times] 10[sup [minus]4] emu/g[center dot]Oe at room temperature. 41 refs., 1 fig., 4 tabs.

Kalogirou, O. (Univ. of Hamburg (Germany) Aristotle Univ., Thessaloniki (Greece))

1993-02-01

269

Preparation and Magnetic Properties of SrFe12O19 Ferrites Suitable for Use in Self-Biased LTCC Circulators  

NASA Astrophysics Data System (ADS)

Strontium ferrites with different Bi2O3 content are prepared by the solid phase method, and their magnetic properties are investigated primarily. The Bi2O3 additive and sintering temperature separately exhibit a strong effect on the sintering density, crystal structure, and magnetic properties of the ferrites. As to the ferrites with 3 wt% Bi2O3, the relatively high sintering density ?s, saturation magnetization Ms, and intrinsic coercivity Hci can be obtained at a low sintering temperature of 900°C even much lower. Furthermore, the effective magnetic anisotropy constant Keff and magnetic anisotropy field Ha of the ferrites are calculated from the magnetization curve by the law of approach to saturation. It is suggested that the low-temperature sintered SrFe12O19 ferrites with Ms of 285.6 kA/m and Ha of 1564.6 kA/m possess a significant potentiality for applying in the self-biased low-temperature co-fired ceramics circulators from 34 to 40 GHz.

Peng, Long; Hu, Yue-Bin; Guo, Cheng; Li, Le-Zhong; Wang, Rui; Hu, Yun; Tu, Xiao-Qiang

2015-01-01

270

Preparation and magnetic properties of BaFe12O19/Ni0.8Zn0.2Fe2O4 nanocomposite ferrite  

NASA Astrophysics Data System (ADS)

Nanocomposite of hard (BaFe12O19)/soft ferrite (Ni0.8Zn0.2Fe2O4) have been prepared by the sol-gel process. The nanocomposite ferrite are formed when the calcining temperature is above 800 °C. It is found that the magnetic properties strongly depend on the presintering treatment and calcining temperature. The “bee waist” type hysteresis loops for samples disappear when the presintering temperature is 400 °C and the calcination temperature reaches 1100 °C owing to the exchange-coupling interaction. The remanence of BaFe12O19/Ni0.8Zn0.2Fe2O4 nanocomposite ferrite with the mass ratio of 5:1 is higher than a single phase ferrite. The specific saturation magnetization, remanence magnetization and coercivity are 63 emu/g, 36 emu/g and 2750 G, respectively. The exchange-coupling interaction in the BaFe12O19/Ni0.8Zn0.2Fe2O4 nanocomposite ferrite is discussed.

Wang, Yan; Huang, Ying; Wang, Qiufen

2012-09-01

271

Polyelectrolyte/magnetite nanoparticle multilayers: preparation and structure characterization.  

PubMed

Polyelectrolyte composite planar films containing a different number of iron oxide (Fe3O4) nanoparticle layers have been prepared using the layer-by-layer adsorption technique. The nanocomposite assemblies were characterized by ellipsometry, UV-vis spectroscopy, and AFM. Linear growth of the multilayer thickness with the increase of the layer number, N, up to 12 reflects an extensive character of this parameter in this range. A more complicated behavior of the refractive index is caused by changes in the multilayer structure, especially for the thicker nanocomposites. A quantitative analysis of the nanocomposite structure is provided comparing a classical and a modified effective medium approach taking into account the influence of light absorption by the Fe3O4 nanoparticles on the complex refractive index of the nanocomposite and contributions of all components to film thickness. Dominant influence of co-adsorbed water on their properties was found to be another interesting peculiarity of the nanocomposite film. This effect, as well as possible film property modulation by light, is discussed. PMID:17958452

Grigoriev, D; Gorin, D; Sukhorukov, G B; Yashchenok, A; Maltseva, E; Möhwald, H

2007-11-20

272

Preparation and protein immobilization of magnetic dialdehyde starch nanoparticles.  

PubMed

Superparamagnetic Fe3O4 nanoparticles were obtained using a hydrolysis product of starch, i.e., ?-d-glucose, as the reducing agent and without any additional stabilizer and dispersant by a facile and green method at mild temperature. Magnetic dialdehyde starch nanoparticles (MDASN) were successfully synthesized with dialdehyde starch (DAS) as wrapper and epichlorohydrin as cross-linker by coembedding method. Bovine serum albumin (BSA) as a model drug was immobilized on the suface of MDASN. The particle size distribution of MDASN was 50-150 nm, and the average size was about 100 nm. The content of aldehyde group in DAS was 59.5%, and the package rate of DAS in MDASN was 33.2%. The loading amount and encapsulation efficiency of MDASN loading BSA were 5.0% and 54.4%, respectively. The saturation magnetization of MDASN at 300 K was 29.5 emu/g without coercivity and remanence. The as-prepared MDASN have not only lots of aldehyde functional groups but also stronger magnetic response, which might have potential applications such as drug carriers and targeted drug release. PMID:23528154

Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

2013-04-11

273

Preparation and evaluation of nanoparticles for directed tissue engineering.  

PubMed

Herein we describe the preparation of a nanoparticulate system formed from an RGD-functionalized chitosan derivative by complexation with chondroitin sulfate. These bioactive complexes were developed to promote wound healing by inducing adhesion and subsequently migration of skin cells. The particles were characterized for their size, surface charge, stability and shape. Briefly, the nanoparticles were found to be stable up to 7 days in water at a diameter of 150-200 nm and a positive charge of 20 mV. In physiological media the particles swell significantly but remain intact. Tested in an in vitro cell model of human dermal fibroblasts, the particles were shown to promote cell adhesion and induce spreading in human dermal fibroblasts. The mean surface area per cell was found to be increased by three-fold (n=3 assays, p<0.01), for the cells plated on particles exposing RGD-peptides when compared to cells on control particles. This indicates a stimulation of the cells due to the exposure of the bioactive RGD-moieties and an enhanced cell-biomaterial interaction. Using nanoparticles is a novel approach to direct cellular behavior with numerous possible applications in tissue engineering such as substrate for dermal and epithelial cells, injectable suspensions or as building blocks to form scaffolds. PMID:23046666

Hansson, Annasara; Di Francesco, Tiziana; Falson, Françoise; Rousselle, Patricia; Jordan, Olivier; Borchard, Gerrit

2012-12-15

274

Preparation and characterization of ultra-hydrophobic calcium carbonate nanoparticles  

NASA Astrophysics Data System (ADS)

Anionic surfactants based on fatty acids are usually used to modify the particle surface properties of CaCO3 with the aim to enhance its dispersion and compatibility with polymer matrices. In this study sodium oleate was used for the preparation of ultrahydrophobic CaCO3 nanoparticles using a wet carbonation route. The effect of sodium oleate on the characteristics, particle size, morphology, surface potential, thermal decomposition and hydrophobicity of CaCO3, was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), Zeta potential, thermogravimetric analysis (TGA) and water contact angle measurement (WCA). The results showed that the addition of 2 wt% sodium oleate helps in reducing the particle size from 2 ?m length scalenohedral particles to 45 nm rhombohedral particles and modifying of the hydrophobic property of CaCO3.

Barhoum, A.; El-Sheikh, S. M.; Morsy, F.; El-Sherbiny, S.; Reniers, F.; Dufour, T.; Delplancke, M. P.; Van Assche, G.; Rahier, H.

2014-08-01

275

Enrichment of magnetic alignment stimulated by {gamma}-radiation in core-shell type nanoparticle Mn-Zn ferrite  

SciTech Connect

Core shell type nanoparticle Mn{sub x}Zn{sub 1-x}Fe{sub 2}O{sub 4} systems with x=0.55, 0.65 and 0.75 were prepared using autocombustion method. The systems were characterized using tools like XRD and IR for structure confirmation. Magnetic parameter measurements like Saturation magnetization and coercivity were obtained from hysteresis loop which exhibited a symmetry shift due to core shell nature of the nanoparticles. Nanoparticles of particle size between 21.2nm to 25.7nm were found to show 20 percent shrinkage after being radiated by the {gamma}-radiation. This is due to variation in the cation distribution which also affects the cell volume of the cubic cell. Lattice constant reduction observed is reflected in the magnetic properties of the samples. A considerable hike in the saturation magnetization of the samples was observed due to enrichment of magnetic alignment in the magnetic core of the particles. Samples under investigation were irradiated with gamma radiation from Co{sup 60} source for different time intervals.

Naik, P. P.; Tangsali, R. B. [Department of Physics, Goa University, Taleigao Plateau, Goa-403206 (India); Sonaye, B.; Sugur, S. [Goa Medical College, Bambolim, Goa (India)

2013-02-05

276

Enrichment of magnetic alignment stimulated by ?-radiation in core-shell type nanoparticle Mn-Zn ferrite  

NASA Astrophysics Data System (ADS)

Core shell type nanoparticle MnxZn1-xFe2O4 systems with x=0.55, 0.65 & 0.75 were prepared using autocombustion method. The systems were characterized using tools like XRD and IR for structure confirmation. Magnetic parameter measurements like Saturation magnetization and coercivity were obtained from hysteresis loop which exhibited a symmetry shift due to core shell nature of the nanoparticles. Nanoparticles of particle size between 21.2nm to 25.7nm were found to show 20 percent shrinkage after being radiated by the ?-radiation. This is due to variation in the cation distribution which also affects the cell volume of the cubic cell. Lattice constant reduction observed is reflected in the magnetic properties of the samples. A considerable hike in the saturation magnetization of the samples was observed due to enrichment of magnetic alignment in the magnetic core of the particles. Samples under investigation were irradiated with gamma radiation from Co60 source for different time intervals.

Naik, P. P.; Tangsali, R. B.; Sonaye, B.; Sugur, S.

2013-02-01

277

Relaxivities of hydrogen protons in aqueous solutions of PEG-coated rod-shaped manganese-nickel-ferrite (Mn0.4Ni0.6Fe2O4) nanoparticles  

NASA Astrophysics Data System (ADS)

Spinel-structured manganese (Mn)-nickel (Ni)-ferrite nanoparticles were synthesized using a chemical co-precipitation method. Coating with PEG (polyethylene glycol) was simultaneously conducted along with the synthesis of Mn-Ni-ferrites. The X-ray diffraction (XRD) and the Fourier-transform infrared (FTIR) analyses revealed a cubic spinel ferrite structure of the synthesized nanoparticles. Transmission electron microscopy (TEM) images showed that the synthesized nanoparticles were rod-shaped with a uniform size distribution and that the average length and width were 15.13 ± 1.32 nm and 3.78 ± 0.71 nm, respectively. The bonding status of PEG on the nanoparticle surface was checked by using FTIR. The relaxivities of the hydrogen protons in the aqueous solutions of the coated particles were determined by using nuclear magnetic resonance (NMR) spectrometry. The T1 and the T2 relaxivities were 0.34 ± 0.11 mM-1s-1 and 29.91 ± 0.98 mM-1s-1, respectively. This indicates that the synthesized PEG-coated Mn-Ni-ferrite nanoparticles are suitable for use as T2 contrast agents.

Iqbal, Yousaf; Bae, Hongsub; Rhee, Ilsu; Hong, Sungwook

2014-11-01

278

RESEARCH Open Access Predictive Toxicology of cobalt ferrite  

E-print Network

RESEARCH Open Access Predictive Toxicology of cobalt ferrite nanoparticles: comparative in Korenstein1* Abstract Background: Cobalt-ferrite nanoparticles (Co-Fe NPs) are attractive for nanotechnology that oxidative stress is one possible mechanism for the toxicity of Co-Fe NPs. Keywords: Nanotoxicology, Cobalt-ferrite

Paris-Sud XI, Université de

279

Comparison of Different Crosslinking Methods for Preparation of Docetaxel-loaded Albumin Nanoparticles  

PubMed Central

In the last step of desolvation method for preparation of albumin nanoparticles, glutaraldehyde (GA) is added to stabilize the newly formed nanoparticles. Due to undesirable effects of GA, the objective of this study was to evaluate alternative methods of crosslinking including ultraviolet (UV) irradiation, adding of glucose and combination of both methods. The nanoparticles were prepared by desolvation procedure. Final particle size, zeta potential, FTIR, scanning electron micrograph, cellular uptake and cell toxicity of nanoparticles crosslinked with UV and/or glucose were compared with commonly crosslinked nanoparticles with GA. Moreover, drug release and stability parameters of docetaxel-loaded albumin nanoparticles were investigated. Size of all nanoparticles prepared by different methods was in the same range (100-200 nm). Zeta potential showed the same results except for those treated with UV. The results of FTIR assay were the same for all groups. Although crosslinking by UV or glucose alone resulted in cytotoxic effects, combination of UV and glucose had less cytotoxic effects compared to GA. Cellular uptake of nanoparticles crosslinked with UV + glucose and GA showed similar results. The release of docetaxel from UV + glucose and GA crosslinked nanoparticles showed the same biphasic release. These data support the idea that crosslinking with a combination of UV and glucose can be a promising alternative method for production of docetaxel-loaded albumin nanoparticles with the advantage of omitting toxic GA.

Niknejad, Hassan; Mahmoudzadeh, Raziyeh

2015-01-01

280

Facile preparation of sphere-like copper ferrite nanostructures and their enhanced visible-light-induced photocatalytic conversion of benzene  

SciTech Connect

Graphical abstract: - Highlights: • Spinel CuFe{sub 2}O{sub 4} nanospheres were successfully synthesized via a facile method. • CuFe{sub 2}O{sub 4} nanospheres showed high photocatalytic activity toward benzene. • Ethyl acetate, carboxylic acid and aldehyde were the intermediate products. - Abstract: Spinel copper ferrite nanospheres with diameters of about 116 nm were synthesized in high yield via a facile solvothermal route. The prepared nanospheres had cubic spinel structure and exhibited good size uniformity and regularity. The band-gap energy of CuFe{sub 2}O{sub 4} nanospheres was calculated to be about 1.69 eV, indicating their potential visible-light-induced photocatalytic activity. The dramatically enhanced photocatalytic activity of the CuFe{sub 2}O{sub 4} nanospheres was evaluated via the photocatalytic conversion of benzene under Xe lamp irradiation. By using the in situ FTIR technique, ethyl acetate, carboxylic acid and aldehyde could be regarded as the intermediate products, and CO{sub 2} was produced as the final product during the reaction process. This study provided new insight into the design and preparation of functional nanomaterials with sphere structure in high yield, and the as-grown architectures demonstrated an excellent ability to remove organic pollutants in the atmosphere.

Shen, Yu, E-mail: shenyuqing0322@gmail.com [School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China); Wu, Yanbo; Xu, Hongfeng; Fu, Jie [School of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028 (China); Li, Xinyong; Zhao, Qidong; Hou, Yang [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024 (China)

2013-10-15

281

Thiolated chitosan nanoparticles for enhancing oral absorption of docetaxel: preparation, in vitro and ex vivo evaluation  

PubMed Central

The aim of this study was to prepare and evaluate mucoadhesive core-shell nanoparticles based on copolymerization of thiolated chitosan coated on poly methyl methacrylate cores as a carrier for oral delivery of docetaxel. Docetaxel-loaded nanoparticles with various concentrations were prepared via a radical emulsion polymerization method using cerium ammonium nitrate as an initiator. The physicochemical properties of the obtained nanoparticles were characterized by: dynamic light-scattering analysis for their mean size, size distribution, and zeta potential; scanning electron microscopy and transmission electron microscopy for surface morphology; and differential scanning calorimetry analysis for confirmation of molecular dispersity of docetaxel in the nanoparticles. Nanoparticles were spherical with mean diameter below 200 nm, polydispersity of below 0.15, and positive zeta potential values. The entrapment efficiency of the nanoparticles was approximately 90%. In vitro release studies showed a sustained release characteristic for 10 days after a burst release at the beginning. Ex vivo studies showed a significant increase in the transportation of docetaxel from intestinal membrane of rat when formulated as nanoparticles. Cellular uptake of nanoparticles was investigated using fluoresceinamine-loaded nanoparticles. Docetaxel nanoparticles showed a high cytotoxicity effect in the Caco-2 and MCF-7 cell lines after 72 hours. It can be concluded that by combining the advantages of both thiolated polymers and colloidal particles, these nanoparticles can be proposed as a drug carrier system for mucosal delivery of hydrophobic drugs. PMID:21289989

Saremi, Shahrooz; Atyabi, Fatemeh; Akhlaghi, Seyedeh Parinaz; Ostad, Seyed Nasser; Dinarvand, Rassoul

2011-01-01

282

Thiolated chitosan nanoparticles for enhancing oral absorption of docetaxel: preparation, in vitro and ex vivo evaluation.  

PubMed

The aim of this study was to prepare and evaluate mucoadhesive core-shell nanoparticles based on copolymerization of thiolated chitosan coated on poly methyl methacrylate cores as a carrier for oral delivery of docetaxel. Docetaxel-loaded nanoparticles with various concentrations were prepared via a radical emulsion polymerization method using cerium ammonium nitrate as an initiator. The physicochemical properties of the obtained nanoparticles were characterized by: dynamic light-scattering analysis for their mean size, size distribution, and zeta potential; scanning electron microscopy and transmission electron microscopy for surface morphology; and differential scanning calorimetry analysis for confirmation of molecular dispersity of docetaxel in the nanoparticles. Nanoparticles were spherical with mean diameter below 200 nm, polydispersity of below 0.15, and positive zeta potential values. The entrapment efficiency of the nanoparticles was approximately 90%. In vitro release studies showed a sustained release characteristic for 10 days after a burst release at the beginning. Ex vivo studies showed a significant increase in the transportation of docetaxel from intestinal membrane of rat when formulated as nanoparticles. Cellular uptake of nanoparticles was investigated using fluoresceinamine-loaded nanoparticles. Docetaxel nanoparticles showed a high cytotoxicity effect in the Caco-2 and MCF-7 cell lines after 72 hours. It can be concluded that by combining the advantages of both thiolated polymers and colloidal particles, these nanoparticles can be proposed as a drug carrier system for mucosal delivery of hydrophobic drugs. PMID:21289989

Saremi, Shahrooz; Atyabi, Fatemeh; Akhlaghi, Seyedeh Parinaz; Ostad, Seyed Nasser; Dinarvand, Rassoul

2011-01-01

283

Composition controlled synthesis of PCL-PEG Janus nanoparticles: magnetite nanoparticles prepared from one-pot photo-click reaction.  

PubMed

The aim of this study is to investigate the effect of polymer nature on the morphology of synthesized nanoparticles. Super paramagnetic iron oxide nanoparticles (SPIONs) were prepared by co-precipitation method and then reacted with (3-mercaptopropyl) trimethoxysilane to obtain thiol-decorated SPIONs. Acrylated poly(caprolactone) and methoxy poly(ethylene glycol) were prepared, and then "thiol-ene click" reaction was performed under UV irradiation to attach two types of polymers on the surface of magnetite nanoparticles via the "photo-click" reaction method. Computational modelling was used for the prediction of the self-assembly of polymers on the surface of SPIONs, which determines the morphology of polymer coated nanoparticles. PMID:25666985

Khoee, S; Bagheri, Y; Hashemi, A

2015-02-19

284

Composition controlled synthesis of PCL-PEG Janus nanoparticles: magnetite nanoparticles prepared from one-pot photo-click reaction  

NASA Astrophysics Data System (ADS)

The aim of this study is to investigate the effect of polymer nature on the morphology of synthesized nanoparticles. Super paramagnetic iron oxide nanoparticles (SPIONs) were prepared by co-precipitation method and then reacted with (3-mercaptopropyl) trimethoxysilane to obtain thiol-decorated SPIONs. Acrylated poly(caprolactone) and methoxy poly(ethylene glycol) were prepared, and then ``thiol-ene click'' reaction was performed under UV irradiation to attach two types of polymers on the surface of magnetite nanoparticles via the ``photo-click'' reaction method. Computational modelling was used for the prediction of the self-assembly of polymers on the surface of SPIONs, which determines the morphology of polymer coated nanoparticles.

Khoee, S.; Bagheri, Y.; Hashemi, A.

2015-02-01

285

FACILE PREPARATION OF NANOPARTICLES BY INTRAMOLECULAR CROSSLINKING OF ISOCYANATE FUNCTIONALIZED COPOLYMERS  

PubMed Central

A new synthetic approach to the preparation of intramolecularly collapsed nanoparticles under mild, room temperature conditions has been developed from commercially available vinyl monomers. Reaction of isocyanate functionalized linear copolymers with a diamine in dilute solution leads to the efficient formation of nanoparticles where the diameter of the nanoparticle can be varied by controlling both the molecular weight and mole percentage of isocyanate repeat units. Physical properties for the intramolecularly collapsed nanoparticles were fully consistent with a three-dimensional structure and analysis of the collapse reaction revealed that approximately 75% of the isocyanate groups along the backbone underwent crosslinking with 25% being available for further reaction with mono-functional amines. This stepwise consumption of the isocyanates allows the chemical and physical properties of the nanoparticles to be further tuned and significantly opens up the range of nanoparticles that can be prepared using this mild and highly efficient chemistry. PMID:20717499

Beck, J. Benjamin; Killops, Kato L.; Kang, Taegon; Sivanandan, Kulandaivelu; Bayles, Andrea; Mackay, Michael E.; Wooley, Karen L.; Hawker, Craig J.

2009-01-01

286

Preparation and characterization of PEG-Mentha oil nanoparticles for housefly control.  

PubMed

Nanoparticles of Mentha × piperita essential oil were prepared by melt-dispersion method. The nanoparticles prepared at varying oil doses (5-10%, w/v) showed an encapsulation efficiency of 78.2-83.4%, while the oil load was observed to range between 3.64 and 7.46%. The average particle size of the nanoparticles varied between 226 and 331 nm, while polydispersity index showed variation between 0.547 and 1.000. DSC analysis indicated endothermic reaction during formation of nanoparticles, while a 2-term exponential kinetic model was followed during oil release. Nanoparticles showed considerable mortality against housefly larvae in lab (100%) as well as simulated field condition after first week (93%) and 6th week (57%) of application. This was the first study utilizing controlled release property of nanoparticles to formulate a cost effective product for breeding site application against housefly. PMID:24287110

Kumar, Peeyush; Mishra, Sapna; Malik, Anushree; Satya, Santosh

2014-04-01

287

Magnetic properties of Fe-Ni nanoparticles prepared by co-precipitation method  

NASA Astrophysics Data System (ADS)

Many methods have been extended for the preparation of nanoparticles. One of the most important methods is the chemical wet process, e.g. the co-precipitation method that has been used for the preparation of Fe-Ni nanoparticles by the authors. XRD patterns show that the nanoparticles are amorphous before calcination and crystallized after calcination. SEM images show that the grain size of the Fe-Ni particles is in 50-300 nanometre range and that the texture of the nanoparticles after calcination was smoother than before calcination. Hysteresis loops show that the Fe-Ni nanoparticles are superparamagnetic before calcination, because the carbonate phase still exists in the sample, and that they are ferromagnetic materials after calcination. For 40Fe-60Ni nanoparticles after calcination, Hc = 0.12 and Bs = 4800 Oe, being very different in respect to the bulk 40Fe-60Ni alloy.

Davarpanah, A. M.; Mirzae, A. A.; Sargazi, M.; Feizi, M.

2008-08-01

288

Preparation and Characterization of Mg Substituted NiCuZn Nano Ferrites for Multilayer Chip Inductors  

NASA Astrophysics Data System (ADS)

The present paper examines the effect of magnesium substitution on structural and magnetic properties of NiCuZn nano ferrites synthesized by sol - gel method. Formation of single phase spinel structure was confirmed both from XRD and FTIR. The initial permeability shows decreasing trend with increasing Mg concentration due to reduced magnetization, grain size and increased magneto - crystalline anisotropy constant. At the same time, the cut off frequency increases with increasing Mg content. This is attributed to domain wall pinning arising due to the presence of non magnetic magnesium ions. Also the permeability is observed to be constant up to 10MHz frequency range showing compositional stability and quality of the material. The magnetic loss factor shows very low values at higher frequencies. It is concluded that even though both zinc and magnesium are non magnetic ions, substitution of one cation by another prone to influence the magnetic properties due to their change in dimension and cation distribution among the two available sites of a spinel system. These samples have advantages of low sintering temperature find applications in multilayer chip inductors due to their high and constant permeability even at higher frequencies.

Ch, Sujatha; Reddy K, Venugopal; Babu K, Sowri; Reddy A, R. C.; K, H. Rao

2012-02-01

289

A voltammetric sensor on the basis of bismuth nanoparticles prepared by the method of gas condensation  

Microsoft Academic Search

A procedure is developed for the immobilization of bismuth nanoparticles prepared by the method of gas condensation on inert\\u000a supports manufactured by the screen printing method using carbon-containing inks. The electrochemical behavior of the immobilized\\u000a bismuth nanoparticles is investigated, and the conditions of their electrochemical activation are found. The composition of\\u000a the modifying suspension “bismuth nanoparticles-liquid” is optimized. The elaborated

N. A. Malakhova; A. A. Mysik; S. Yu. Saraeva; N. Yu. Stozhko; M. A. Uimin; A. E. Ermakov; Kh. Z. Brainina

2010-01-01

290

Chitosan–Pluronic nanoparticles as oral delivery of anticancer gemcitabine: preparation and in vitro study  

PubMed Central

Nanoparticles have proven to be an effective delivery system with few side effects for anticancer drugs. In this study, gemcitabine-loaded nanoparticles have been prepared by an ionic gelation method using chitosan and Pluronic® F-127 as a carrier. Prepared nanoparticles were characterized using dynamic light scattering, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy, and transmission electron microscopy. Different parameters such as concentration of sodium tripolyphosphate, chitosan, Pluronic, and drug on the properties of the prepared nanoparticles were evaluated. In vitro drug release was studied in phosphate-buffered saline (PBS; pH = 7.4). The cytotoxicity of the nanoparticles was assayed in the HT-29 colon cancer cell line. The mucoadhesion behavior of the nanoparticles was also studied by mucus glycoprotein assay. The prepared nanoparticles had a spherical shape with positive charge and a mean diameter ranging between 80 to 170 nm. FT-IR and DSC studies found that the drug was dispersed in its amorphous form due to its potent interaction with nanoparticle matrix. Maximum drug encapsulation efficiency was achieved at 0.4 mg/mL gemcitabine while maximum drug loading was 6% obtained from 0.6 mg/mL gemcitabine. An in vitro drug release study at 37°C in PBS (pH = 7.4) exhibited a controlled release profile for chitosan–Pluronic® F-127 nanoparticles. A cytotoxicity assay of gemcitabine-loaded nanoparticles showed an increase in the cytotoxicity of gemcitabine embedded in the nanoparticles in comparison with drug alone. The mucoadhesion study results suggest that nanoparticles could be considered as an efficient oral formulation for colon cancer treatment. PMID:22605934

Hosseinzadeh, Hosniyeh; Atyabi, Fatemeh; Dinarvand, Rassoul; Ostad, Seyed Naser

2012-01-01

291

Preparation and Characterization of Self-Assembled Aminated Agarose Loaded with Fluorescein Isothiocyanate Nanoparticles  

Microsoft Academic Search

A number of organic fluorescent molecules self-assembling into nanoparticles can significantly promote their fluorescent effects. In this paper, a novel fluorescein isothiocyanate labeling aminated agarose (FITC-AA) is prepared and tested as an effective fluorescent labeling agent. FITC-AA self-assembled into nanoparticles with a diameter between 104.54 ? 164.94 nm at below 37°C by the gelling effect of agarose. FITC-AA nanoparticles could

Lingmin Zhang; Xiaohui Peng; Shunqing Tang

2011-01-01

292

Electromagnetic properties of low-temperature-sintered Ba 3Co 2? x Zn x Fe 24O 41 ferrites prepared by solid state reaction method  

Microsoft Academic Search

Hexagonal ferrites Ba3Co2?xZnxFe24O41 (X=0–2.0) were prepared by a solid state reaction method. The influences of Zn content (X) on the Z-type phase formation temperature and specific saturation magnetization were investigated. With a small amount of sintering aids, highly dense hexaferrite ceramics with fine-grained microstructure were obtained after sintering at a relatively low temperature below 900°C. The hexaferrite ceramics show excellent

Xiaohui Wang; Longtu Li; Shuiyuan Su; Zhenxing Yue

2004-01-01

293

Preparation and characterization of carboxymethyl guar gum nanoparticles.  

PubMed

Carboxymethyl guar gum nanoparticles (CMGGNPs) were synthesized by nanoprecipitation and sonication method. This method was used for the first time for the synthesis of carboxymethyl guar gum nanoparticles. It was found that the formation of nanoparticles might depend upon the sonication time, solvent, and stirring time. Nanoparticles were characterized by SEM, TEM, XRD and FTIR. The sizes of the particles in suspension have been found in the range 12-30nm. It was concluded that such type of nanoparticles may be used in pharmaceutical and drug delivery. PMID:24832982

Gupta, Anek Pal; Verma, Devendra Kumar

2014-07-01

294

Synthesis and Optical Properties of Sulfide Nanoparticles Prepared in Dimethylsulfoxide  

SciTech Connect

Many methods have been reported for the formation of sulfide nanoparticles by the reaction of metallic salts with sulfide chemical sources in aqueous solutions or organic solvents. Here, we report the formation of sulfide nanoparticles in dimethylsulfoxide (DMSO) by boiling metallic salts without sulfide sources. The sulfide sources are generated from the boiling of DMSO and react with metallic salts to form sulfide nanoparticles. In this method DMSO functions as a solvent and a sulfide source as well as a stabilizer for the formation of the nanoparticles. The recipe is simple and economical making sulfide nanoparticles formed in this way readily available for many potential applications.

Li, Yuebin; Ma, Lun; Zhang, Xing; Joly, Alan G.; Liu, Zuli; Chen, Wei

2008-11-01

295

Preparation, characterization and adsorption properties of chitosan nanoparticles for eosin Y as a model anionic dye  

Microsoft Academic Search

The present study dealt with the adsorption of eosin Y, as a model anionic dye, from aqueous solution using chitosan nanoparticles prepared by the ionic gelation between chitosan and tripolyphosphate. The nanoparticles were characterized by atomic force microscopy (AFM), size and zeta potential analysis. A batch system was applied to study the adsorption of eosin Y from aqueous solution by

Wen Li Du; Zi Rong Xu; Xin Yan Han; Ying Lei Xu; Zhi Guo Miao

2008-01-01

296

Preparation of avidin-labeled protein nanoparticles as carriers for biotinylated peptide nucleic acid  

Microsoft Academic Search

The possibility of preparing protein nanoparticles followed by covalent linkage of avidin was investigated. Free sulfhydryl groups were introduced onto the surface of protein nanoparticles either by aldehyde quenching with cysteine or reaction of free amino groups with 2-iminothiolane. The number of primary amino groups and sulfhydryl groups on the surface of the resulting particles was quantified with site-specific reagents.

Klaus Langer; Conrad Coester; Carolin Weber; Hagen von Briesen; Jörg Kreuter

2000-01-01

297

Li Reaction Behavior of GaP Nanoparticles Prepared by a Sodium Naphthalenide Reduction Method  

E-print Network

Li Reaction Behavior of GaP Nanoparticles Prepared by a Sodium Naphthalenide Reduction Method reaction phenomena of GaP nanoparticles (sodium naphthalenide reduction method at 390 for use in anode materials in Li secondary batteries due to decomposition of the surfactants during

Cho, Jaephil

298

Preparation, Structure, and Properties of Magnetic Materials Based on Co-Containing Nanoparticles  

Microsoft Academic Search

The recent experimental data on the preparation and properties of materials containing Co-based magnetic nanoparticles are summarized. Particular attention is focused on the synthesis of cobalt nanoparticles in “rigid” matrices (polymers, metals, and solid surfaces) and their static magnetic properties, which are of great importance for practical applications. The conclusion is made that surface effects play an important role in

S. P. Gubin; Yu. A. Koksharov

2002-01-01

299

The electrical properties of manganese ferrite powders prepared by two different methods  

NASA Astrophysics Data System (ADS)

Two powder samples of manganese ferrite (MnFe2O4) with different morphology and particle size 30-40 nm, denoted by A and B have been synthesized by different methods starting from MnCl2·4H2O and FeCl3·6H2O. Sample A was obtained by co-precipitation followed by calcination at 900 °C and sample B has been obtained by hydrothermal method. XRD analysis show that calcination leads to the occurrence of other phases than MnFe2O4, therefore the hydrothermal method gives better results. From the temperature dependence of the electrical resistivity, measured over the range 300-483 K, the activation energy, ?E, of the investigated samples has been evaluated, resulting in 0.43 eV (for sample A) and 0.32 eV (for sample B). The conductivity mechanism in the samples was explained in terms of Mott's variable range hopping (VRH) model. The results showed that the density of states at the Fermi level is constant over the investigated temperature range, being in order of 0.788 ×1017eV-1cm-3 (for sample A) and 2.05 ×1017eV-1cm-3 (for sample B). The hopping distance, R and the hopping energy, W (parameters of VRH model) have also been computed. Room temperature values are R=27.08 nm and W=152 meV for sample A and R=21.29 nm and W=120 meV for sample B.

Lungu, A.; Malaescu, I.; Marin, C. N.; Vlazan, P.; Sfirloaga, P.

2015-04-01

300

Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol  

E-print Network

Carbon supported PtNi nanoparticles were prepared by hydrazine reduction of Pt and Ni precursor salts under different conditions, namely by conventional heating (PtNi-1), by prolonged reaction at room temperature (PtNi-2) ...

Deivaraj, T.C.

301

Wear-resistant and electromagnetic absorbing behaviors of oleic acid post-modified ferrite-filled epoxy resin composite coating  

NASA Astrophysics Data System (ADS)

The post-modified Mn-Zn ferrite was prepared by grafting oleic acid on the surface of Mn-Zn ferrite to inhibit magnetic nanoparticle aggregation. Fourier Transform Infrared (FT-IR) spectroscopy was used to characterize the particle surfaces. The friction and electromagnetic absorbing properties of a thin coating fabricated by dispersing ferrite into epoxy resin (EP) were investigated. The roughness of the coating and water contact angle were measured using the VEECO and water contact angle meter. Friction tests were conducted using a stainless-steel bearing ball and a Rockwell diamond tip, respectively. The complex permittivity and complex permeability of the composite coating were studied in the low frequency (10 MHz-1.5 GHz). Surface modified ferrites are found to improve magnetic particles dispersion in EP resulting in significant compatibility between inorganic and organic materials. Results also indicate that modified ferrite/EP coatings have a lower roughness average value and higher water contact angle than original ferrite/EP coatings. The enhanced tribological properties of the modified ferrite/EP coatings can be seen from the increased coefficient value. The composite coatings with modified ferrite are observed to exhibit better reflection loss compared with the coatings with original ferrite.

Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

2015-03-01

302

Biomedical and environmental applications of magnetic nanoparticles  

Microsoft Academic Search

This paper presents an overview of syntheses and applications of magnetic nanoparticles (MNPs) at the Institute of Materials Science, Vietnam Academy of Science and Technology. Three families of oxide MNPs, magnetite, manganite and spinel ferrite materials, were prepared in various ways: coprecipitation, sol–gel and high energy mechanical milling. Basic properties of MNPs were characterized by Vibrating Sample Magnetometer (VSM) and

Dai Lam Tran; Van Hong Le; Hoai Linh Pham; Thi My Nhung Hoang; Thi Quy Nguyen; Thien Tai Luong; Phuong Thu Ha; Xuan Phuc Nguyen

2010-01-01

303

Preparation and property of polyvinyl alcohol-based film embedded with gold nanoparticles  

Microsoft Academic Search

Gold nanoparticles were prepared by a simple heat-treated method using polyvinyl alcohol (PVA) as reducing and stabilizing\\u000a agent in this article. UV\\/Vis spectroscopy was used to monitor the preparation. The formation of a sharp band at ~530 nm in\\u000a the UV\\/Vis spectra and morphological characters revealed by transmission electron microscopy indicated the generation of Au\\u000a nanoparticles. The PVA film embedded with

Changmei Sun; Rongjun Qu; Chunnuan Ji; Yanfeng Meng; Chunhua Wang; Yanzhi Sun; Lingyan Qi

2009-01-01

304

Temperature dependent structural and magnetic properties of Cerium substituted Co-Cr ferrite prepared by auto-combustion method  

NASA Astrophysics Data System (ADS)

The effects of heat treatment on a nano-crystalline spinel ferrite with chemical formula CoCr0.04CexFe1.96-xO4 (x=0.06) were investigated in the present work. The sample was prepared by the auto-combustion method and then heat treated at 700-1200 °C for 8 h. The sample heat treated at these temperatures was investigated using thermo-gravimetric analyses and differential scanning calorimetry, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometery. The XRD patterns and IR spectra confirmed that the synthesized materials were of single phase at and above 900 °C. The average particle size was found to be in the range of 30.8-63.8 nm estimated by the Scherer formula. IR studies confirm two main absorption bands in the frequency range of 400-800 cm-1 arising due to the tetrahedral (A-site) and octahedral (B-site) stretching vibrations. The average grain size increased with the increase of temperature while distribution of particles became homogeneous as observed by scanning electron microscope. The saturation magnetization was increased gradually from 7.4 to 59.6 emu/g with the increase of temperature. The coercivity lies in the range of 248-811 Oe as a function of temperature. The obtained results suggest that the investigated materials may be potential candidates for high density recording media applications.

Mustafa, Ghulam; Islam, M. U.; Zhang, Wenli; Jamil, Yasir; Asif Iqbal, M.; Hussain, Mudassar; Ahmad, Mukhtar

2015-03-01

305

Preparation and Antibacterial Activity Evaluation of 18-?-glycyrrhetinic Acid Loaded PLGA Nanoparticles  

PubMed Central

The aim of the present study was to formulate poly (lactide-co-glycolide) (PLGA) nanoparticles loaded with 18-?-glycyrrhetinic acid (GLA) with appropriate physicochemical properties and antimicrobial activity. GLA loaded PLGA nanoparticles were prepared with different drug to polymer ratios, acetone contents and sonication times and the antibacterial activity of the developed nanoparticles was examined against different gram-negative and gram-positive bacteria. The antibacterial effect was studied using serial dilution technique to determine the minimum inhibitory concentration of nanoparticles. Results demonstrated that physicochemical properties of nanoparticles were affected by the above mentioned parameters where nanoscale size particles ranging from 175 to 212 nm were achieved. The highest encapsulation efficiency (53.2 ± 2.4%) was obtained when the ratio of drug to polymer was 1:4. Zeta potential of the developed nanoparticles was fairly negative (-11±1.5). In-vitro release profile of nanoparticles showed two phases: an initial phase of burst release for 10 h followed by a slow release pattern up to the end. The antimicrobial results revealed that the nanoparticles were more effective than pure GLA against P. aeuroginosa, S. aureus and S. epidermidis. This improvement in antibacterial activity of GLA loaded nanoparticles when compared to pure GLA may be related to higher nanoparticles penetration into infected cells and a higher amount of GLA delivery in its site of action. Herein, it was shown that GLA loaded PLGA nanoparticles displayed appropriate physicochemical properties as well as an improved antimicrobial effect.

Darvishi, Behrad; Manoochehri, Saeed; Kamalinia, Golnaz; Samadi, Nasrin; Amini, Mohsen; Mostafavi, Seyyed Hossein; Maghazei, Shahab; Atyabi, Fatemeh; Dinarvand, Rassoul

2015-01-01

306

Fluorescence of silicon nanoparticles prepared by nanosecond pulsed laser  

SciTech Connect

A pulsed laser fabrication method is used to prepare fluorescent microstructures on silicon substrates in this paper. A 355 nm nanosecond pulsed laser micromachining system was designed, and the performance was verified and optimized. Fluorescence microscopy was used to analyze the photoluminescence of the microstructures which were formed using the pulsed laser processing technique. Photoluminescence spectra of the microstructure reveal a peak emission around 500 nm, from 370 nm laser irradiation. The light intensity also shows an exponential decay with irradiation time, which is similar to attenuation processes seen in porous silicon. The surface morphology and chemical composition of the microstructure in the fabricated region was also analyzed with multifunction scanning electron microscopy. Spherical particles are produced with diameters around 100 nm. The structure is compared with porous silicon. It is likely that these nanoparticles act as luminescence recombination centers on the silicon surface. The small diameter of the particles modifies the band gap of silicon by quantum confinement effects. Electron-hole pairs recombine and the fluorescence emission shifts into the visible range. The chemical elements of the processed region are also changed during the interaction between laser and silicon. Oxidation and carbonization play an important role in the enhancement of fluorescence emission.

Liu, Chunyang, E-mail: chunyangliu@126.com; Sui, Xin; Yang, Fang; Ma, Wei; Li, Jishun; Xue, Yujun [Henan University of Science and Technology, Luoyang, 471003 (China)] [Henan University of Science and Technology, Luoyang, 471003 (China); Fu, Xing [Tianjin University, Tianjin, 300072 (China)] [Tianjin University, Tianjin, 300072 (China)

2014-03-15

307

General preparation for Pt-based alloy nanoporous nanoparticles as potential nanocatalysts  

PubMed Central

Although Raney nickel made by dealloying has been used as a heterogeneous catalyst in a variety of organic syntheses for more than 80 years, only recently scientists have begun to realize that dealloying can generate nanoporous alloys with extraordinary structural characteristics. Herein, we achieved successful synthesis of a variety of monodisperse alloy nanoporous nanoparticles via a facile chemical dealloying process using nanocrystalline alloys as precursors. The as-prepared alloy nanoporous nanoparticles with large surface area and small pores show superior catalytic properties compared with alloyed nanoparticles. It is believed that these novel alloy nanoporous nanoparticles would open up new opportunities for catalytic applications. PMID:22355556

Wang, Dingsheng; Zhao, Peng; Li, Yadong

2011-01-01

308

Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents  

PubMed Central

Summary Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process can result in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of NaCl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV–visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag4 2+. The increase of the plasmon absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the “green” plasmonic silver nanoparticles is also supported by a strong multicolor luminesce signal emitted by the plasmonic particles during 473 nm excitation.

Ærøe Hyllested, Jes; Espina Palanco, Marta; Hagen, Nicolai; Mogensen, Klaus Bo

2015-01-01

309

Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents.  

PubMed

Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process can result in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of NaCl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV-visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag4 (2+). The increase of the plasmon absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the "green" plasmonic silver nanoparticles is also supported by a strong multicolor luminesce signal emitted by the plasmonic particles during 473 nm excitation. PMID:25821667

Ærøe Hyllested, Jes; Espina Palanco, Marta; Hagen, Nicolai; Mogensen, Klaus Bo; Kneipp, Katrin

2015-01-01

310

Noncrystalline structure of Ni-P nanoparticles prepared by liquid pulse discharge.  

PubMed

Noncrystalline nickel phosphide (Ni-P) nanoparticles have drawn great attention due to their high potential as catalysts. However, the structure of noncrystalline Ni-P nanoparticles is still unknown, which may shed light on explaining the catalysis mechanism of the Ni-P nanoparticles. In this paper, noncrystalline Ni-P nanoparticles were synthesized. Their morphology, particle size, element contents, local atomic structures, as well as the catalysis in the thermal decomposition of ammonium perchlorate were studied. The results demonstrate that the as-prepared Ni-P nanoparticles are spherical with an average diameter of about 13.5?nm. The Ni and P contents are, respectively, 78.15% and 21.85%. The noncrystalline nature of the as-prepared Ni-P nanoparticles can be attributed to cross-linkage between P-doping f.c.c.-like Ni centers and Ni3P-like P centers. The locally ordered Ni centers and P centers are the nuclei sites, which can explain well the origin of initial nuclei to form the crystalline phases after high-temperature annealing. The starting temperature of high-temperature decomposition of ammonium perchlorate was found having a significant decrease in the presence of the noncrystalline Ni-P nanoparticles. Therefore, the as-prepared noncrystalline Ni-P nanoparticles can be used as a potential catalyst in the thermal decomposition of ammonium perchlorate. PMID:25723939

Tan, Yuanyuan; Yu, Hongying; Wu, Zhonghua; Yang, Bin; Gong, Yu; Yan, Shi; Du, Rong; Chen, Zhongjun; Sun, Dongbai

2015-03-01

311

Preparation and properties of bio-compatible magnetic Fe 3O 4 nanoparticles  

NASA Astrophysics Data System (ADS)

In this work, we study the preparation and properties of bio-compatible magnetic nanoparticles for immunoassay and DNA detection. The magnetite (Fe 3O 4) nanoparticles were prepared by a chemical co-precipitation method and dextran was selected as the surfactant to suspend the nanoparticles. Suspended particles associated with avidin followed by biotin were qualitatively analyzed by enzyme-linked immunosorbent assay (ELISA) method. We found further the ethylenediamine blocked activated residual groups efficiently, hence enhancing the attachment of biotin for probing the avidin.

Chan, H. T.; Do, Y. Y.; Huang, P. L.; Chien, P. L.; Chan, T. S.; Liu, R. S.; Huang, C. Y.; Yang, S. Y.; Horng, H. E.

2006-09-01

312

Optical investigations on indium oxide nano-particles prepared through precipitation method  

SciTech Connect

Visible light emitting indium oxide nanoparticles were synthesized by precipitation method. Sodium hydroxide dissolved in ethanol was used as a precipitating agent to obtain indium hydroxide precipitates. Precipitates, thus formed were calcined at 600 deg. C for 1 h to obtain indium oxide nanoparticles. The structure of the particles as determined from the X-Ray diffraction pattern was found to be body centered cubic. The phase transformation of the prepared nanoparticles was analyzed using thermogravimetry. Surface morphology of the prepared nanoparticles was analyzed using high resolution-scanning electron microscopy and transmission electron microscopy. The results of the analysis show cube-like aggregates of size around 50 nm. It was found that the nanoparticles have a strong emission at 427 nm and a weak emission at 530 nm. These emissions were due to the presence of singly ionized oxygen vacancies and the nature of the defect was confirmed through Electron paramagnetic resonance analysis.

Seetha, M.; Bharathi, S.; Dhayal Raj, A. [Thin film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore (India); DRDO-BU center for life sciences, Bharathiar University, Coimbatore (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore, Tamilnadu, 641 046 (India); DRDO-BU center for life sciences, Bharathiar University, Coimbatore (India); Nataraj, D. [Thin film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore (India); DRDO-BU center for life sciences, Bharathiar University, Coimbatore (India)

2009-12-15

313

Water driven stabilization of ZnS nanoparticles prepared by exploding wire technique  

NASA Astrophysics Data System (ADS)

ZnS nanoparticles, prepared employing exploding wire technique (EWT), demonstrate water-induced stabilization with time. The structural evolution of ZnS nanoparticles and their interaction with the surrounding aqueous media is systematically studied at the three distinct stages of time. The structural properties of nanoparticles were examined by an assortment of characterization techniques. However, in this article we focus on x-ray diffraction (XRD) and x-ray photoelectron spectroscopic (XPS) investigation of nanoparticles. The XRD results indicate transformation of hexagonal phase of prepared ZnS nanocrystals. The lattice constants and strain in ZnS nanoparticles are estimated at each stage of transition. Alteration in crystal structure of ZnS nanoparticles, transforming in presence of water, is an outcome of gradual variation in lattice constants and strain. Variation in stoichiometry of ZnS nanoparticles, at respective stages of transformation, is found through XPS analysis. Furthermore, in order to determine the alterations in the oxidation state and energies of the nanoparticle constituents, line shape analysis of Zn 2p3/2 peaks at three stages, is also performed. Thus, XPS analysis, accompanied with the XRD interpretations, vividly deciphers the structural evolution of ZnS nanoparticles in aqueous environment.

Goswami, Navendu; Sen, P.

2014-04-01

314

[Preparation, characterization and surface-enhanced Raman properties of agarose gel/gold nanoparticles hybrid].  

PubMed

Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Naniocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Experimental data indicated a uniform distribution of gold nanoparticles adsorbed on agarose gel network And the excellent optical absorption properties were shown. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nano-composites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules Nile blue A. Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. PMID:25474948

Ma, Xiao-yuan; Liu, Ying; Wang, Zhou-ping

2014-08-01

315

[Preparation, characterization and surface-enhanced Raman properties of agarose gel/gold nanoparticles hybrid].  

PubMed

Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Naniocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Experimental data indicated a uniform distribution of gold nanoparticles adsorbed on agarose gel network And the excellent optical absorption properties were shown. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nano-composites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules Nile blue A. Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. PMID:25508727

Ma, Xiao-yuan; Liu, Ying; Wang, Zhou-ping

2014-08-01

316

Non-linear optical properties of silver nanoparticles prepared by hydrogen reduction method  

NASA Astrophysics Data System (ADS)

Silver nanoparticles have been prepared using hydrogen gas as the reducing agent for silver nitrate and poly(vinyl pyrrolidone) as the capping agent; the reaction was carried out at 70 °C for 3 h. The size of the nanoparticles was found to be about 20 nm as analyzed using transmission electron micrographs. The X-ray diffraction pattern revealed the face-centered cubic (fcc) structure of silver nanoparticles. The linear absorption of Ag nanoparticles, ?, is obtained about 3.71 cm -1. The non-linear refractive indices of silver nanoparticles were defined by the z-scan technique using CW He-Ne laser ( ? = 632.8 nm) at different incident intensities. The magnitude of non-linear refractive index ( n2) was measured to be in the order of 10 -7 (cm 2/W) with a negative sign. Therefore self-defocusing phenomena is taking placed for Ag nanoparticles.

Majles Ara, M. H.; Dehghani, Z.; Sahraei, R.; Nabiyouni, G.

2010-04-01

317

Nanoparticles  

NASA Astrophysics Data System (ADS)

MnFe2O4 nanoparticles of various particle sizes were prepared by co-precipitation, in which different hydroxide concentrations were employed to control particle growth. X-ray diffraction and scanning electron microscopy were used to investigate the nanoparticle structure and morphology (shape and size). The particle size increased with increasing hydroxide concentration. The magnetization and coercivity field were measured by vibrating sample magnetometry. Changes in magnetic behavior were observed in the magnetic hysteresis loop curves of nanoparticles with increasing hydroxide concentration. In the absence of hydroxide, nanoparticles exhibited paramagnetic behavior. Increasing the hydroxide concentration caused a gradual conversion to ferrimagnetic behavior. An increased Néel temperature was observed with increasing hydroxide concentration, and the saturation magnetization exhibited a sharp decrease. Nonuniform hysteresis was observed in the magnetization curve for the sample prepared from hydroxide and ammonium.

Vaez-Zadeh, Mehdi; Mohammadi, Ali

2014-07-01

318

Gamma radiation roused lattice contraction effects investigated by Mössbauer spectroscopy in nanoparticle Mn-Zn ferrite  

NASA Astrophysics Data System (ADS)

Nanopowders of MnxZn1-xFe2O4 with x=0.4, 0.5 and 0.6 were synthesized using a combustion synthesis method. X-ray diffraction (XRD) patterns obtained on samples confirmed formation of monophasic cubic phase material. Lattice parameters and X-ray densities were obtained from rietvield refinement of the XRD patterns. All samples were radiated with gamma radiation with a dose of 200 Gy obtained from 60Co source. Structural and physical parameters, such as lattice constant, X-ray density and particle size, determined for as prepared samples (SA) and gamma irradiated samples (SR), showed extraordinary variations in their values. Saturation magnetizations (MS), remnant magnetization (MR) and coercive field (HC) for both sets of samples illustrated an enhancement in their values for SR samples. Investigations were carried out using Mössbauer spectroscopy to divulge structural and magnetic information of all samples. Room temperature Mössbauer spectra were fitted with five magnetic sextets and a symmetric paramagnetic doublet for the data obtained on samples except for x=0.4, SA sample. The presence of well defined doublets in the spectra of SA and SR samples is attributes of superparamagnetism, indicating the reduction in A-B superexchange interaction due to dilution of sub-lattice by Zn ions. Cation distribution at A site and B site, estimated from Mössbauer data exhibited amazing alterations which were highly stable. The variations in physical, structural and magnetic properties observed are attributed to change of Fe2+/Fe3+ and Mn+2/Mn+3 ratios in gamma-irradiated samples.

Naik, P. P.; Tangsali, R. B.; Meena, S. S.; Bhatt, Pramod; Sonaye, B.; Sugur, S.

2014-09-01

319

Preparation of highly dispersed core/shell-type titania nanocapsules containing a single Ag nanoparticle.  

PubMed

Core/shell-type titania nanocapsules containing a single Ag nanoparticle were prepared. Ag nanoparticles were prepared using the reduction of silver nitrate with hydrazine in the presence of cetyltrimethylammonium bromide (CTAB) as protective agent. The sol-gel reaction of titanium tetraisopropoxide (TTIP) was used to prepare core/shell-type titania nanocapsules with CTAB-coated Ag nanoparticles as the core. TEM observations revealed that the size of the core (Ag particle) and the thickness of the shell (titania) of the core/shell particles obtained are about 10 nm and 5-10 nm, respectively. In addition, the nanocapsules were found to be dispersed in the medium as individual particles without aggregation. Moreover, titania coating caused the surface plasmon absorption of Ag nanoparticles to shift toward the longer wavelength side. PMID:16608315

Sakai, Hideki; Kanda, Takashi; Shibata, Hirobumi; Ohkubo, Takahiro; Abe, Masahiko

2006-04-19

320

Fe\\/Ba Ratio Effect on Magnetic Properties of Barium Ferrite Powders Prepared by Microwave-Induced Combustion  

Microsoft Academic Search

Barium ferrite powders were successfully synthesized by microwave-induced combustion. The magnetic properties of barium ferrite powders with various Fe\\/Ba ratios varying from 11 to 12 annealed at various temperatures in the range of 850-1050°C were determined. The resultant powders were investigated by X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), differential thermal analyzer\\/thermogravimeter (DTA\\/TG), and surface area

Yen-Pei Fu; Cheng-Hsiung Lin; Ko-Ying Pan

2003-01-01

321

Magnetic properties of Co1-xZnxFe2O4 spinel ferrite nanoparticles synthesized by starch-assisted sol-gel autocombustion method and its ball milling  

NASA Astrophysics Data System (ADS)

In this article, Co1-xZnxFe2O4 (x=0.0 and 0.5) spinel ferrite nanoparticles were achieved at 800 °C by starch-assisted sol-gel autocombustion method. To further reduce the particle size, these synthesized ferrite nanoparticles were ball-milled for 2 h. X-ray diffraction patterns demonstrated single phase formation of Co1-xZnxFe2O4 (x=0.0 and 0.5) spinel ferrite nanoparticles. FE-SEM analysis indicated the nanosized spherical particles formation with spherical morphology. The change in Raman modes and relative intensity were observed due to ball milling and consequently decrease of particle size and cationic redistribution. An X-ray Photoelectron Spectroscopy (XPS) result indicated that Co2+, Zn2+ and Fe3+ exist in octahedral and tetrahedral sites. The cationic redistribution of Zn2+ and consequently Fe3+ occurred between octahedral and tetrahedral sites after ball-milling. The change in saturation magnetization (Ms) and coercivity (Hc) with decrease of nanocrystalline size and distribution of cations in spinel ferrite were observed.

Yadav, Raghvendra Singh; Havlica, Jaromir; Hnatko, Miroslav; Šajgalík, Pavol; Alexander, Cigá?; Palou, Martin; Bartoní?ková, Eva; Bohá?, Martin; Frajkorová, Františka; Masilko, Jiri; Zmrzlý, Martin; Kalina, Lukas; Hajdúchová, Miroslava; Enev, Vojt?ch

2015-03-01

322

Interrogation of CoxZnyNizFe2O4 ferrite nanoparticles for insight into specific power loss for medical hyperthermia  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles (MNPs) have shown to be viable candidates as heat sources for magnetic hyperthermia under an alternating magnetic field. The present work investigates heating characteristics of sol-gel processed ferro-magnetic CoxZnyNizFe2O4 (ferrite) nanoparticles with different magnetic properties. The nanoparticles were irradiated by a radio-frequency magnetic field through a 5-turns coil using a 1.2 kW heating system with variable frequency in the 295-315 kHz range and a maximum current output of 100 A. Higher specific power losses were measured for nanoparticles that had lower coercivities. The advantage of having a high specific power loss for clinical applications is that a minute amount of nanoparticle has to be introduced in the body to adequately destroy malignant tumor cells.[4pt] |c|c|c|c|c|c| Name & Grain Size & Mr & Ms & Hc & SPL100A&(nm) & (emu/g) & (emu/g) & (Oe) & (W/g^2)Ni0.5Zn0.5Fe2O4 & 48.7 & 2.85 & 47.5 & 42.2 & 84 ± 2Co0.4Ni0.4Zn0.2Fe2O4 & 46 & 3.29 & 26.2 & 75.3 & 28 ± 3NiFe2O4 & 42.9 & 3.47 & 14.8 & 146 & 17.0 ± 0.5CoFe2O4 & 34.5 & 7.01 & 22.2 & 626 & 0.64 ± 0.05

Jagoo, Zafrullah; Kozlowski, Gregory; Turgut, Zafer; Rebrov, Evgeny

2012-04-01

323

Preparation and in-vitro evaluation of indomethacin nanoparticles  

PubMed Central

Background and the purpose of the study During the last two decades one of the most important problems in drug formulations has been low aqueous solubility of new molecules. However, numerous techniques, such as milling, co-solvent solubilization and solid dispersion have been used conventionally for aqueous solubility enhancement and the rate of solubility. Recently, nanoparticle engineering processes have been developed and reported for pharmaceutical applications to increase the dissolution rate of low-soluble drugs which in turn may leads to substantial increases in bioavailability. In this study, a controlled precipitation method was used to produce indomethacin nano-solid suspension in a polymeric matrix (as a model), in order to increase the solubility and rate of the dissolution of poorly soluble model drug. Methods Nano-solid suspension of indomethacin in polyvinyl pyrrolidine (PVP) was prepared by controlled precipitation technique, characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and evaluated for in vitro solubility and dissolution rate. Results and major conclusion Absence of thermal and diffractional peaks in DSC and XRD studies indicated that indomethacin interacts with PVP in solid phase. The solubility of indomethacin in nano-solid suspension compared to crystalline form was increased to about four-fold. It was found that particle size distribution depend to the polymer MW and drug: polymer ratios. Spectroscopy methods and Transmission Electron Microscopy (TEM) images showed that indomethacin dispersed as amorphous nanosize particles in freeze dried powder. Enhanced solubility and dissolution rate of indomethacin compared to physical mixtures and crystalline form of indomethacin (polymorph I), demonstrated that it interacts with PVP via hydrogen bond and probably forming eutectic mixture. PMID:22615616

Rezaei Mokarram, A.; Kebriaee zadeh, A.; Keshavarz, M.; Ahmadi, A.; Mohtat, B.

2010-01-01

324

[Preparation of polyelectrolyte microcapsules containing ferrosoferric oxide nanoparticles].  

PubMed

In this study, polyelectrolyte microcapsules have been fabricated by biocompatible ferrosoferric oxide nanoparticles (Fe3O4 NPs) and poly allyamine hydrochloride (PAH) using layer by layer assembly technique. The Fe3O4 NPs were prepared by chemical co-precipitation, and characterized by transmission electron microscopy (TEM) and infrared spectrum (IR). Quartz cell also was used as a substrate for building multilayer films to evaluate the capability of forming planar film. The result showed that Fe3O4 NPs were selectively deposited on the surface of quartz cell. Microcapsules containing Fe3O4 NPs were fabricated by Fe3O4 NPs and PAH alternately self-assembly on calcium carbonate microparticles firstly, then 0.2 molL(-1) EDTA was used to remove the calcium carbonate. Scanning electron microscopy (SEM), Zetasizer and vibrating sample magnetometer (VSM) were used to characterize the microcapsule's morphology, size and magnetic properties. The result revealed that Fe3O4 NPs and PAH were successfully deposited on the surface of CaCO3 microparticles, the microcapsule manifested superparamagnetism, size and saturation magnetization were 4.9 +/- 1.2 microm and 8.94 emu x g(-1), respectively. As a model drug, Rhodamin B isothiocyanate labeled bovine serum albumin (RBITC-BSA) was encapsulated in microcapsule depended on pH sensitive of the microcapsule film. When pH 5.0, drug add in was 2 mg, the encapsulation efficiency was (86.08 +/- 3.36) % and the drug loading was 8.01 +/- 0.30 mg x m(L-1). PMID:21465817

Liu, Xiao-Qing; Zheng, Chun-Li; Zhu, Jia-Bi

2011-01-01

325

Magnetic properties of hexagonal strontium ferrite thick film synthesized by sol-gel processing using SrM nanoparticles  

NASA Astrophysics Data System (ADS)

Strontium ferrite SrFe 12O 19 (SrM) thick films have been synthesized using a spinning coating sol-gel process. The coating sol was formed from SrFe 12O 19 powders dispersed in the strontium ferrite raw sol. XRD, TEM, SEM, vibrating sample magnetometer (VSM) and ac susceptometer were employed to evaluate the structure, composition and magnetic properties of SrFe 12O 19 thick films. The results indicated that a uniform and crack-free coating of Strontium ferrite with ˜15 ?m thickness can be produced with a good deal of consistency. The magnetization hysteresis loops were almost the same for magnetic fields both applied in parallel and perpendicular.

Ghasemi, Ali; Morisako, Akimitsu; Liu, Xiaoxi

326

Enhanced bioavailability of sirolimus via preparation of solid dispersion nanoparticles using a supercritical antisolvent process  

PubMed Central

Background The aim of this study was to improve the physicochemical properties and bioavailability of poorly water-soluble sirolimus via preparation of a solid dispersion of nanoparticles using a supercritical antisolvent (SAS) process. Methods First, excipients for enhancing the stability and solubility of sirolimus were screened. Second, using the SAS process, solid dispersions of sirolimus-polyvinylpyrrolidone (PVP) K30 nanoparticles were prepared with or without surfactants such as sodium lauryl sulfate (SLS), tocopheryl propylene glycol succinate, Sucroester 15, Gelucire 50/13, and Myrj 52. A mean particle size of approximately 250 nm was obtained for PVP K30-sirolimus nanoparticles. Solid state characterization, kinetic solubility, powder dissolution, stability, and pharmacokinetics were analyzed in rats. Results X-ray diffraction, differential scanning calorimetry, and high-pressure liquid chromatography indicated that sirolimus existed in an anhydrous amorphous form within a solid dispersion of nanoparticles and that no degradation occurred after SAS processing. The improved supersaturation and dissolution of sirolimus as a solid dispersion of nanoparticles appeared to be well correlated with enhanced bioavailability of oral sirolimus in rats. With oral administration of a solid dispersion of PVP K30-SLS-sirolimus nanoparticles, the peak concentration and AUC0?12h of sirolimus were increased by approximately 18.3-fold and 15.2-fold, respectively. Conclusion The results of this study suggest that preparation of PVP K30-sirolimus-surfactant nanoparticles using the SAS process may be a promising approach for improving the bioavailability of sirolimus. PMID:22162657

Kim, Min-Soo; Kim, Jeong-Soo; Park, Hee Jun; Cho, Won Kyung; Cha, Kwang-Ho; Hwang, Sung-Joo

2011-01-01

327

Preparation and anti-bacterial properties of a temperature sensitive gel containing silver nanoparticles  

Technology Transfer Automated Retrieval System (TEKTRAN)

The purpose of this study was to prepare a novel temperature-sensitive spray gel containing silver nanoparticles and investigate its anti-bacterial properties in vitro. Methods: The aqueous complex gel was prepared by Pluronic F127 (18-22%) and Pluronic F68 (3-9%) through a cold method to obtain a p...

328

Preparation of compact nanoparticle clusters from polyethylene glycol-coated gold nanoparticles by fine-tuning colloidal interactions.  

PubMed

Low-molecular weight polyethylene glycol (PEG) has a lower critical solution temperature well outside the boiling point of water at ambient pressure, but it can be reduced at high ionic strengths. We extend this concept to trigger the clustering of gold nanoparticles through the control of colloidal interactions. At high ionic strengths, low-molecular weight (<2000 Da) mPEG-SH-modified gold nanoparticles show clustering with an increase in the solution temperature. The clustering temperature decreases with an increasing ionic strength. The clustering is attributed to the delicate interplay between the high ionic strength and elevated temperature and is interpreted in terms of chain collapse of the surface-grafted PEG molecules. The chain collapse results in a change in the steric interaction term, whereas the high ionic strength eliminates the double-layer repulsion between the particles. The observations are backed by nanoparticle interaction model calculations. We found that the intermediate attractive potential on the order of a few kT allows the experimental fabrication of compact nanoparticle clusters in agreement with theoretical predictions. The approach presented here has the potential to be extended on the externally triggered preparation of nanoparticle clusters with different types of nanoparticles. PMID:25686160

Zámbó, Dániel; Radnóczi, György Z; Deák, András

2015-03-10

329

Preparation and Optical Characterization of Core–Shell Bimetal Nanoparticles  

Microsoft Academic Search

Chemical approaches allow for the synthesis of highly defined metal heteronanostructures, such as core–shell nanospheres.\\u000a Because the material in the metal nanoparticles determines the plasmon resonance-induced absorption band, control of particle\\u000a composition results in control of the position of the absorption band. Metal deposition on gold or silver nanoparticles yielded\\u000a core–shell particles with modified optical properties. UV–vis spectroscopy on solution-grown,

A. Steinbrück; A. Csáki; G. Festag; W. Fritzsche

2006-01-01

330

Microbial mediated preparation, characterization and optimization of gold nanoparticles  

PubMed Central

The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl4 solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl4, pH of medium and temperature of shaker incubator. The R2 value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations. PMID:25763059

Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

2014-01-01

331

Microbial mediated preparation, characterization and optimization of gold nanoparticles.  

PubMed

The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl4 solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl4, pH of medium and temperature of shaker incubator. The R(2) value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations. PMID:25763059

Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

2014-01-01

332

Preparation and characterization of ketoprofen loaded eudragit RS polymeric nanoparticles for controlled release  

NASA Astrophysics Data System (ADS)

Nanospheres containing ketoprofen (Keto) and polymer eudragit RS were prepared using an emulsion solvent evaporation method. The ultrasonic probe (VCX500, vibracell) was used as a tool to disperse oil phase into aqueous phase leading to water/oil emulsion. Nanoparticles were successfully prepared and their morphologies and diameters were confirmed by transmission electron microscope (TEM) and dynamic light scattering (DLS), respectively. The result showed that particles were spherical with submicron size. The particle size was dependent on the RS concentration, emulsification tools and the types of organic solvents. For the encapsulation ability, Keto-loaded RS nanoparticle showed 9.8% of Keto in nanoparticle, which was evaluated by high-performance liquid chromatography (HPLC). Moreover, the drug release behavior of Keto-loaded eudragit RS nanoparticle was also investigated in vitro at pH 7.4 and compared to referential profenid.

Anh, Nguyen Tuan; Chi, Nguyen T.; Khai Tran, T.; Tuyen Dao, T. P.; Nhan Le, N. T.; Mau Chien, Dang; Hoai, Nguyen To

2012-12-01

333

Preparation of lisinopril-capped gold nanoparticles for molecular imaging of angiotensin-converting enzyme  

NASA Astrophysics Data System (ADS)

Overexpression of angiotensin-converting enzyme (ACE) has been associated with the pathophysiology of cardiac and pulmonary fibrosis. Moreover, the prescription of ACE inhibitors, such as lisinopril, has shown a favorable effect on patient outcome for patients with heart failure or systemic hypertension. Thus targeted imaging of the ACE would be of crucial importance for monitoring tissue ACE activity as well as the treatment efficacy in heart failure. In this respect, lisinopril-coated gold nanoparticles were prepared to provide a new type of probe for targeted molecular imaging of ACE by tuned K-edge computed tomography (CT) imaging. The preparation involved non-modified lisinopril, using its primary amine group as the anchoring function on the gold nanoparticles surface. The stable lisinopril-coated gold nanoparticles obtained were characterized by UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM). Their zeta potential was also measured in order to assess the charge density on the modified gold nanoparticles (GNPs).

Li, Yuan; Baeta, Cesar; Aras, Omer; Daniel, Marie-Christine

2009-05-01

334

Preparation of low-crystalline apatite nanoparticles and their coating onto quartz substrates.  

PubMed

We prepared low-crystalline apatite nanoparticles and coated them onto a surface of a Au/Cr-plated quartz substrate by the electrophoretic deposition (EPD) method or by using a self-assembled monolayer of 11-mercaptoundecanoic acid (SAM method). Low-crystalline apatite nanoparticles around 10 nm in size with extremely low contents of undesirable residual products were obtained by adding (NH(4))(2)HPO(4) aqueous droplets into a modified synthetic body fluid solution that contained Ca(CH(3)COO)(2). The apatite nanoparticles were successfully coated by either the EPD method or the SAM method; the nanoparticle coating achieved by the SAM method was more uniform than that achieved by the EPD method. The present SAM method is expected to be a promising technique for obtaining a quartz substrate coated with apatite nanoparticles, which can be used as a quartz crystal microbalance device. PMID:22426746

Kawashita, Masakazu; Taninai, Koji; Li, Zhixia; Ishikawa, Kunio; Yoshida, Yasuhiro

2012-06-01

335

Solvent-stabilized photoconductive metal phthalocyanine nanoparticles: preparation and application in single-layered photoreceptors.  

PubMed

This article features solvent-stabilized nanoparticles of photoconductive metal phthalocyanines (MPcs) with small particle sizes and narrow size distributions, which are tractable building blocks for photoelectric devices. The preparation and stabilization mechanism of 1,2-dichloroethane (DCE)-stabilized oxovanadium phthalocyanine (VOPc) and oxotitanium phthalocyanine (TiOPc) nanoparticles are discussed. It is found for the first time that the DCE-stabilized TiOPc and VOPc nanoparticles are positively charged with zeta potentials of about +66 mV, which is ascribed to the electron transfer from the nanoparticles to DCE molecules. The excellent xerographic properties of the single-layered photoreceptors based on TiOPc or VOPc nanoparticles and the charge transport mechanism of these photoreceptors are discussed. The strategy for further improving the xerographic properties of single-layered photoreceptors is proposed. PMID:20437502

Wang, Yuan; Liang, Dejian

2010-04-01

336

Y 2O 3:Eu 3+ (5 mol%) with Ag nanoparticles prepared by citrate precursor  

NASA Astrophysics Data System (ADS)

Y 2O 3:Eu 3+ (5 mol% Eu 3+) and Y 2O 3:Eu 3+ (5 mol% Eu 3+) containing 1 mol% of Ag nanoparticles were prepared by heat treatment of a viscous resin obtained via citrate precursor. TEM and EDS analyses showed that Y 2O 3:Eu 3+ (5 mol% Eu 3+) is formed by nanoparticles with an average size of 12 nm, which increases to 30 nm when Ag is present because the effect of metal induced crystallization occurs. Ag nanoparticles with a size of 9 nm dispersed in Y 2O 3:Eu 3+ (5 mol% Eu 3+) were obtained and the surface plasmon effect on Ag nanoparticles was observed. The emission around 612 nm assigned to the Eu 3+ ( 5D 0? 7F 2) transition enhanced when the Ag nanoparticles were present in the Y 2O 3:Eu 3+ luminescent material.

Ferrari, J. L.; Cebim, M. A.; Pires, A. M.; Couto dos Santos, M. A.; Davolos, M. R.

2010-09-01

337

Effects of Microemulsion Preparation Conditions on Drug Encapsulation Efficiency of PLGA Nanoparticles  

NASA Astrophysics Data System (ADS)

Emulsion solvent evaporation technique is widely used to prepare nanoparticles of many organic polymer drug carriers. The mechanism of nanoparticle generation by this technique involves oil-in-water (O/W) microemulsion formation followed by solvent evaporation. Various microemulsion preparation conditions can affect the encapsulation efficiency of drug in the nanoparticulate carrier. In this study, emulsifying speed, emulsifying temperature, and organic-to-aqueous phase ratio were varied and the resulting encapsulation efficiency of a model drug in Poly(Lactide-co-Glycolide) (PLGA) nanoparticles was determined. The organic phase containing PLGA and a model drug dissolved in chloroform was first dispersed in an aqueous solution containing 0.5 %(w/v) Poly(vinyl alcohol) (PVA), which was then homogenized at high speeds. The resulting O/W microemulsion was subsequently subjected to stirring at room temperature for four hours during which the solvent diffused and evaporated gradually. The fine white suspension was centrifuged and freeze-dried. The model drug loading in the PLGA nanoparticles was determined using UV spectrophotometry. Results showed that the encapsulation efficiency of a model drug, salicylic acid, ranged from 8.5% to 17% depending on the microemulsion preparation conditions. Under the same temperature (15 °C) and homogenization speed (19000 rpm) conditions studied, a relatively high organic-to-aqueous phase ratio (1:5) provided salicylic acid loaded PLGA nanoparticles with significantly higher drug encapsulation efficiency. In addition, under all microemulsion preparation conditions, PLGA nanoparticles obtained after solvent evaporation and freeze drying were spherical and aggregation between the nanoparticles was not observed under a high power microscope. This indicates that PLGA nanoparticles with desirable amount of drug and with anticipated size and shape can be realized by controlling emulsification process conditions.

Ng, Set Hui; Ooi, Ing Hong

2011-12-01

338

Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method  

NASA Astrophysics Data System (ADS)

The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution.

Bobadilla, L. F.; García, C.; Delgado, J. J.; Sanz, O.; Romero-Sarria, F.; Centeno, M. A.; Odriozola, J. A.

2012-11-01

339

One-step preparation of ultrafine poly(acrylonitrile) fibers containing silver nanoparticles  

Microsoft Academic Search

A simple one-step method of preparing of ultrafine poly(acrylonitrile) (PAN) fibers containing Ag nanoparticles was developed. Ag+ ions in a PAN solution were directly reduced to produce Ag nanoparticles and the resulting solution was electrospun into ultrafine PAN fibers. N,N-dimethylformamide (DMF) was used as a solvent for PAN as well as a reducing agent for the Ag+ ions. The numbers

Hwang Kyu Lee; Eun Hwan Jeong; Chi Kyoung Baek; Ji Ho Youk

2005-01-01

340

Hydrothermal preparation of one-dimensional assemblies of PbS nanoparticles  

NASA Astrophysics Data System (ADS)

The preparation of one-dimensional assemblies of PbS nanoparticles is described. By treating the suspension of PbCl2 powders in aqueous thioacetamide solution at 120 °C for 18 h, PbS nanoparticles were synthesized in regular chain-like patterns. The particles were less than 100 nm in sizes, and were organized into micron-length assemblies. The starting agents have much influence on the morphology of the products. The possible growth mechanism is also discussed.

Wang, Debao; Yu, Dabin; Mo, Maosong; Liu, Xianming; Qian, Yitai

2003-03-01

341

Preparation of silver nanoparticles on cellulose nanocrystals and the application in electrochemical detection of DNA hybridization  

Microsoft Academic Search

Synthesis of Ag nanopaticles was carried out with carboxylated cellulose nanocrystals as the scaffolds by reducing metallic\\u000a cations using NaBH4. Ag particles with a size less than 10 nm were readily prepared and dispersed well. The carboxyl and hydroxyl groups of carboxylated\\u000a cellulose nanocrystals supplied a coordination effect to adsorb metallic cations and Ag nanoparticles, which prevent the aggregation\\u000a of nanoparticles.

He Liu; Dan Wang; Zhanqian Song; Shibin Shang

2011-01-01

342

Preparation of silver nanoparticles dispersed in polyacrylonitrile nanofiber film spun by electrospinning  

Microsoft Academic Search

Ag nanoparticles dispersed in polyacrylonitrile (PAN) nanofiber film spun by electrospinning were in situ prepared by reduction of silver ions in N2H5OH aqueous solution. The Ag\\/PAN nanocomposite film was characterized by UV absorption spectroscopy, transmission electron microscopy (TEM) and surface-enhanced Raman scattering (SERS) spectroscopy. UV spectrum and TEM image show that silver nanoparticles with average diameter of 10 nm were

Yongzhi Wang; Qingbiao Yang; Guiye Shan; Ce Wang; Jianshi Du; Shugang Wang; Yaoxian Li; Xuesi Chen; Xiabin Jing; Yen Wei

2005-01-01

343

Preparation, characterization, and manipulation of iron platinum, barium titanate, and vanadium oxide nanoparticles  

Microsoft Academic Search

New synthesis strategies for preparation of FePt, BaTiO 3, VO2, V2O3, V2O5 , and V6O13 nanoparticles are presented in this thesis. Electron microscopy, diffraction, elemental analysis, and physical property measurement studies confirm the composition and structure of the synthesized material. Also reported is size-selection of ferromagnetic nanoparticles by binding PEG (2000 MW) ligand to particle surfaces and fractionally precipitating more

William Homer Morris III

2008-01-01

344

Preparation and characteristics of calcium carbonate\\/silica nanoparticles with core-shell structure  

Microsoft Academic Search

In this paper, a step-by-step (SBS) method was used to prepare calcium carbonate\\/silica nanoparticles with core-shell structure. The core of calcium carbonate nanoparticles were cubic shaped with an average size of 48nm obtained in the first step of carbonation method and the shell of SiO2 with thickness about 5nm were coated on the core in the second step of sol-precipitation

Hari Bala; Yishun Zhang; Haibin Ynag; Chengyu Wang; Minggang Li; Xiaotang Lv; Zichen Wang

2007-01-01

345

Synthesis and structural investigation of Pd\\/Ag bimetallic nanoparticles prepared by the solvothermal method  

Microsoft Academic Search

Pd\\/Ag bimetallic nanoparticles have been synthesized successfully by reducing PdCl2 and AgNO3 mixture in ethylene glycol solution using the solvothermal method. The prepared samples have been characterized by UV–vis,\\u000a XRD, TEM, HRTEM, EDS, and XPS, respectively. Moreover, the bimetallic particles possess alloy and core-shell structure from\\u000a the HRTEM images. Here, the lattice fringe spacing of Pd\\/Ag bimetallic nanoparticles corresponds to

Weihua Wang; Gengyu Cao

2007-01-01

346

Gas sensing properties of ZnFe2O4 nanoparticles  

NASA Astrophysics Data System (ADS)

Gas sensing performance of ZnFe2O4 ferrite nanoparticles towards various organic volatile compounds is investigated. A self-combustion of a citrate-gel precursor at ˜90 °C in ambient air followed by annealing at 400 °C for 2 h has been explored to prepare a single phase spinel ferrite powder containing granular nanoparticles of average 23 nm diameters. A powder compact measures chemiresistive sensitivity of 59, 51, and 67% for organic vapor-analytes methanol, ethanol, and acetone respectively of 200 ppm at 250 °C. Excellent sensitivity of the granular nanoparticles results due to a large surface area to volume ratio effect.

Misra, Susmita; Ram, S.

2013-06-01

347

Preparation and biomedical application of a non-polymer coated superparamagnetic nanoparticle  

PubMed Central

We report the preparation of a non-polymer coated superparamagnetic nanoparticle that is stable and biocompatible both in vitro and in vivo. The non-polymer, betaine, is a natural methylating agent in mammalian liver with active surface property. Upon systemic administration, the nanoparticle has preferential biodistribution in mammalian liver and exhibits good reduction of relaxivity time and negative enhancement for the detection of hepatoma nodules in rats using MRI. Our data demonstrate that the non-polymer coated superparamagnetic nanoparticle should have potential applications in biomedicine. PMID:18203447

Du, Lin; Chen, Jianzhao; Qi, Yanting; Li, Dan; Yuan, Chonggang; Lin, Marie C; Yew, David T; Kung, Hsiang-Fu; Yu, Jimmy C; Lai, Lihui

2007-01-01

348

Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route  

Microsoft Academic Search

The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared\\u000a via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH3COO)2·2H2O) and aniline (C6H5NH2) in 6 h refluxing at ?65 °C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed.

Rizwan Wahab; Amrita Mishra; Soon-Il Yun; Young-Soon Kim; Hyung-Shik Shin

2010-01-01

349

Colloidal formulations of etoposide based on poly(butyl cyanoacrylate) nanoparticles: preparation, physicochemical properties and cytotoxicity.  

PubMed

This article describes the preparation, physicochemical characterization and cytotoxicity assessment of novel colloidal formulations of etoposide based on poly(butyl cyanoacrylate) nanoparticles. Nanoparticles were prepared by controlled emulsion polymerization of butyl cyanoacrylate in aqueous medium using two different non-ionic colloidal stabilizers (pluronic F68 and polysorbate 80). The nanoparticles were spherical in shape, with average size ranging from 110-150 nm (empty nanoparticles) to 170-260 nm (drug-loaded nanoparticles), monomodal size distributions, and negative zeta-potentials at pH 7.4. Drug loading efficiency was around 63-68%. More than 80% of the drug was released from the formulations within 6-7h of dialysis experiments. Pluronic-coated nanoparticles possessed lower magnitude of the ?-potentials (around -4 mV) in comparison with the polysorbate-coated ones (around -12 mV). All tested etoposide formulations induced apoptosis in adenocarcinoma human epithelial (A549) cells, as evident from condensation of chromatin and fragmentation of nuclei. It was found that etoposide formulated with poly(butyl cyanoacrylate) nanoparticles and polysorbate 80 exhibited the highest cytotoxicity toward adenocarcinoma cells. PMID:23010022

Yordanov, Georgi; Skrobanska, Ralica; Evangelatov, Alexander

2013-01-01

350

Preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels.  

PubMed

Ag nanoparticles, used for halogen (especially iodine) adsorption and an evaluation of halogen behavior, were embedded in synthesized inorganic-organic hybrid gels. In particular, an irradiation method using an electron beam plays a part in introducing Ag nanoparticles to the organofunctionalized silica gels from AgNO3 solutions in a simple way at atmospheric pressure and room temperature. For preparation of the Ag nanoparticle-embedded inorganic-organic hybrid gels, ligands of ethylenediamine (NH2CH2CH2NH-, TMSen) and mercapto (HS-) functionalized three-dimensional porous SiO2 sol-gels were first synthesized through hydrolysis and condensation reactions, and Ag nanoparticles were then embedded into the ethylenediamine- and mercapto-anchored silica gels each, through electron-beam irradiation. The addition of ligands yielded larger average pore sizes than the absence of any ligand. Moreover, the ethylenediamine ligand led to looser structures and better access of the Ag nanoparticles to the ethylenediamine-anchored gel. As a result, more Ag nanoparticles were introduced into the ethylenediamine-anchored gel. The preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels are discussed in detail. PMID:24245307

Im, Hee-Jung; Lee, Byung Cheol; Yeon, Jei-Won

2013-11-01

351

Electromagnetic properties of low-temperature-sintered Ba 3Co 2- xZn xFe 24O 41 ferrites prepared by solid state reaction method  

NASA Astrophysics Data System (ADS)

Hexagonal ferrites Ba 3Co 2- xZn xFe 24O 41 ( X=0-2.0) were prepared by a solid state reaction method. The influences of Zn content ( X) on the Z-type phase formation temperature and specific saturation magnetization were investigated. With a small amount of sintering aids, highly dense hexaferrite ceramics with fine-grained microstructure were obtained after sintering at a relatively low temperature below 900°C. The hexaferrite ceramics show excellent high-frequency properties such as high initial permeability up to 10, high cut-off frequency over 1.1 GHz and good DC resistivity more than 10 9 ? cm .

Wang, Xiaohui; Li, Longtu; Su, Shuiyuan; Yue, Zhenxing

2004-09-01

352

The preparation and microwave properties of Ba 3Zn Z Co 2? Z Fe 24O 41 ferrite by citrate sol–gel process  

Microsoft Academic Search

A series of Ba3ZnZCo2?ZFe24O41 ferrite with Z=0.0, 0.4, 0.8, 1.2, 1.6 and 2.0 had been prepared by citrate sol–gel process, the result showed that the pure Z-type hexaferrite could be obtained by this process at 1200°C for 5 h. The complex dielectric constant and complex permeability were measured in 100 MHz–6 GHz by using transmission\\/reflection coaxial line method. It showed

Zhang Haijun; Yao Xi; Zhang Liangying

2001-01-01

353

Preparation and characterization of amorphous amphotericin B nanoparticles for oral administration through liquid antisolvent precipitation.  

PubMed

We prepared amphotericin B (AmB) nanoparticles through liquid antisolvent precipitation (LAP) and by freeze-drying to improve the solubility of AmB for oral administration. The LAP was optimized through a single-factor experiment. We determined the effects of surfactants and their concentration, the stirring time, the precipitation temperature, the stirring intensity, the drug concentration and the volume ratio of antisolvent to solvent on the mean particle size (MPS) of the AmB nanoparticles. Increased stirring intensity and precipitation time favored AmB nanoparticles with smaller MPS, but precipitation times exceeding 30 min did not further reduce the MPS. Increased Tween-80 concentration and the drug concentration decreased the MPS of the AmB nanoparticles. Increased precipitation temperature and antisolvent to solvent volume ratio initially decreased the MPS of the AmB nanoparticles, which increased thereafter. Optimum conditions produced AmB nanoparticles with an MPS of 135.1 nm. The AmB nanoparticles were characterized through scanning electron microscopy (SEM), mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TG), solvent residue, drug purity test, and dissolution testing. The analyses indicated that the chemical structure of AmB remained unchanged in the nanoparticles, but the structure was changed from crystalline to amorphous. The residual DMSO in the nanoparticles was 0.24% less than the standard set by the International Conference on Harmonization limit for class III solvents. The AmB nanoparticles exhibited 2.1 times faster dissolution rates and 13 times equilibrium solubility compared with the raw drug. The detection results indicate that the AmB nanoparticles potentially improved the oral absorption of AmB. PMID:24345795

Zu, Yuangang; Sun, Wei; Zhao, Xiuhua; Wang, Weiguo; Li, Yong; Ge, Yunlong; Liu, Ying; Wang, Kunlun

2014-03-12

354

Preparation and characterization of betulin nanoparticles for oral hypoglycemic drug by antisolvent precipitation.  

PubMed

Abstract Betulin, a kind of small molecular compound, was reported that has hypoglycemic effect. Due to its low aqueous solubility and high permeability, betulin has low and variable oral bioavailability. In this work, betulin nanoparticles were thus prepared by antisolvent precipitation for accelerating dissolution of this kind of poorly water-soluble drugs. Ethanol was used as solvent and deionized water was used as antisolvent. The effects of various experimental parameters on the mean particle size (MPS) of nanocrystallization betulin were investigated. The MPS of betulin nanoparticles suspension basically remain unchanged when precipitation time was within 60?min and then increased from 304?nm to 505?nm later. However, the MPS of betulin nanoparticles suspension decreased with increased betulin solution concentration. On the contrary, the MPS of betulin nanoparticles suspension decreased along with the increase of temperature. Stirring intensity and the speed ratio of solvent adding into antisolvent had no significant influences on the MPS of betulin nanoparticles suspension. Betulin nanoparticles suspension with a MPS of approximately 110?nm was achieved under the optimal precipitation conditions. FTIR, Liquid chromatography coupled with tandem mass spectrometry (LC-MS), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to analyze the characteristic of betulin nanoparticles powder. These results show that betulin nanoparticles powder has the same chemical structure as raw drug, but a smaller size and lower crystallinity. The dissolution rate and solubility of betulin nanoparticles powder were separately 3.12 and 1.54 times of raw drug. The bioavailability of betulin nanoparticles powder increased 1.21 times compared with raw betulin. The result of in vivo evaluation on diabetic animals demonstrates that the betulin nanoparticles powder show an excellent hypoglycemic effect compared with raw betulin. In addition, the residual ethanol is less than the ICH (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human) limit for class 3 solvents of 5000?ppm or 0.5% for solvents. PMID:24479653

Zhao, Xiuhua; Wang, Weiguo; Zu, Yuangang; Zhang, Ying; Li, Yong; Sun, Wei; Shan, Chang; Ge, Yunlong

2014-09-01

355

Preparation and characterization of carboxyl functionalization of magnetite nanoparticles for oligonucleotide immobilization  

NASA Astrophysics Data System (ADS)

Fe3O4 nanoparticles prepared by the co-precipitation of Fe2+ and Fe3+ with NH4OH were simply modified by the carboxylic acid group of 3-thiopheneacetic acid (3TA) and meso-2,3-dimercaptosuccinic acid (DMSA). These functionalized Fe3O4 nanoparticles when coated with 3TA and DMSA have increased hydrophilic properties, thus causing them to be well dispersed in aqueous solutions. Then oligonucleotides (5'-AGC T-Amine-3') were immobilized on the carboxylic acid group-modified Fe3O4 nanoparticles. They were characterized by using FT-IR, XRD and TEM. The concentration of the oligonucleotide-modified Fe3O4 nanoparticles was investigated using a UV-vis spectrometer and compared to that of Fe3O4 nanoparticles without any surface modification. The Fe3O4 nanoparticles were spherical and the particle sizes were approximately 10 nm. The immobilizing efficiencies of the Fe3O4 nanoparticles modified with 3TA and DMSA were higher than those of the non-functionalized Fe3O4 nanoparticles.

Kim, Min-Jung; Jang, Dae-Hwan; Choa, Yong-Ho

2010-05-01

356

Streptomycin-loaded PLGA-alginate nanoparticles: preparation, characterization, and assessment  

NASA Astrophysics Data System (ADS)

The aim of this study was to formulate and characterize streptomycin-loaded PLGA-alginate nanoparticles for their potential therapeutic use in Salmonella subsp. enterica ATCC 14028 infections. The streptomycin nanoparticle was prepared by solvent diffusion method, and the other properties such as size, zeta potential, loading efficacy, release kinetics, and antimicrobial strength were evaluated. The survey shows that nanoparticles may serve as a carrier of streptomycin and may provide localized antibacterial activity in the treatment of Salmonellosis. Electron microscopy showed spherical particles with indentations. The average size of the nanoparticles was 90 nm. At pH 7.2, the release kinetics of streptomycin from the nanoparticles was successfully illustrated as an initial burst defined by a first order equation that after this stage, it has a drastic tendency to obtain steady state. Nevertheless, nanoparticles showed loading efficacy nearly about 70-75 %. In addition, the tendency of concentration of streptomycin released from nanoparticles to reach antibacterial activity was similar to that of free streptomycin against PLGA-alginate, but it had threefold more antimicrobial strength in comparison with free streptomycin. This work shows the potential use of streptomycin-loaded PLGA-alginate nanoparticles and its capability.

Asadi, Asadollah

2014-04-01

357

Streptomycin-loaded PLGA-alginate nanoparticles: preparation, characterization, and assessment  

NASA Astrophysics Data System (ADS)

The aim of this study was to formulate and characterize streptomycin-loaded PLGA-alginate nanoparticles for their potential therapeutic use in Salmonella subsp. enterica ATCC 14028 infections. The streptomycin nanoparticle was prepared by solvent diffusion method, and the other properties such as size, zeta potential, loading efficacy, release kinetics, and antimicrobial strength were evaluated. The survey shows that nanoparticles may serve as a carrier of streptomycin and may provide localized antibacterial activity in the treatment of Salmonellosis. Electron microscopy showed spherical particles with indentations. The average size of the nanoparticles was 90 nm. At pH 7.2, the release kinetics of streptomycin from the nanoparticles was successfully illustrated as an initial burst defined by a first order equation that after this stage, it has a drastic tendency to obtain steady state. Nevertheless, nanoparticles showed loading efficacy nearly about 70-75 %. In addition, the tendency of concentration of streptomycin released from nanoparticles to reach antibacterial activity was similar to that of free streptomycin against PLGA-alginate, but it had threefold more antimicrobial strength in comparison with free streptomycin. This work shows the potential use of streptomycin-loaded PLGA-alginate nanoparticles and its capability.

Asadi, Asadollah

2013-04-01

358

Synthesis of cobalt ferrite (CoFe2O4) nanoparticles using combustion, coprecipitation, and precipitation methods: A comparison study of size, structural, and magnetic properties  

NASA Astrophysics Data System (ADS)

In this work the cobalt ferrite (CoFe2O4) nanoparticles are synthesized using three different methods; combustion, coprecipitation, and precipitation. Size, structural, and magnetic properties were determined and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). XRD data analysis showed an average size of 69.5 nm for combustion, 49.5 nm for coprecipitation, and 34.7 nm for precipitation samples which concorded with SEM images. XRD data further revealed a reverse cubic spinel structure with the space group Fd-3m in all three samples. VSM data of samples showed a saturation point in the magnetic field of less than 15 kOe. Magnetization saturation (Ms) was 56.7 emu/g for combustion synthestized samples, 55.8 emu/g for coprecipitation samples, and 47.2 emu/g for precipitation samples. Coercivity (Hc) was 2002 Oe for combustion synthestized samples, 850 Oe for coprecipitation samples, and 233 Oe for precipitation samples. These results show that various methods of nanoparticle synthesis can lead to different particle sizes and magnetic properties. Hc and Ms are greatest in the combustion method and least in precipitation method.

Houshiar, Mahboubeh; Zebhi, Fatemeh; Razi, Zahra Jafari; Alidoust, Ali; Askari, Zohreh

2014-12-01

359

Pt nanoparticles over PEDOT/carbon composites prepared by supercritical carbon dioxide deposition  

NASA Astrophysics Data System (ADS)

In this study, firstly, polyethylenedioxythiophene (PEDOT)/carbon (C) composite material was synthesized by oxidative chemical polymerization. Then, PEDOT/C supported platinum (Pt) nanoparticles were prepared by using supercritical carbon dioxide (scCO2) deposition method. The prepared composite and catalyst were characterized by using BET, TGA, XRD and TEM techniques. The Pt loading over the support was achieved as 10%. TEM results showed that highly dispersed and small nanoparticles over the composite material can be obtained by using scCO2 deposition method.

Bozkurt, Gamze; Memio?lu, Fulya; Bayrakçeken, Ay?e

2014-11-01

360

Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment  

ERIC Educational Resources Information Center

Assimilating green chemistry principles in nanotechnology is a developing area of nanoscience research nowadays. Thus, there is a growing demand to develop environmentally friendly and sustainable methods for the synthesis of nanoparticles that utilize nontoxic chemicals, environmentally benign solvents, and renewable materials to avoid their…

Sharma, R. K.; Gulati, Shikha; Mehta, Shilpa

2012-01-01

361

Preparation of folate-modified pullulan acetate nanoparticles for tumor-targeted drug delivery.  

PubMed

The purpose of this work was to develop a novel nano-carrier with targeting property to tumor. In this study, pullulan acetate (PA) was synthesized by the acetylation of pullulan to simplify the preparation technique of nanoparticles. Folic acid (FA) was conjugated to PA in order to improve the cancer-targeting activity. The products were characterized by proton nuclear magnetic resonance (¹H NMR) spectroscopy. Epirubicin-loaded nanoparticles were prepared by a solvent diffusion method. The loading efficiencies and EPI content increased with the amount of triethylamine (TEA) increasing in some degree. FPA nanoparticles could incorporate more epirubicin than PA nanoparticles. The folate-modified PA nanoparticles (FPA/EPI NPs) exhibited faster drug release than PA nanoparticles (PA/EPI NPs) in vitro. Confocal image analysis and flow cytometry test revealed that FPA/EPI NPs exhibited a greater extent of cellular uptake than PA/EPI NPs against KB cells over-expressing folate receptors on the surface. FPA/EPI NPs also showed higher cytotoxicity than PA/EPI NPs. The cytotoxic effect of FPA/EPI NPs to KB cells was inhibited by an excess amount of folic acid, suggesting that the binding and/or uptake were mediated by the folate receptor. PMID:22747075

Zhang, Hui-zhu; Li, Xue-min; Gao, Fu-ping; Liu, Ling-rong; Zhou, Zhi-min; Zhang, Qi-qing

2010-01-01

362

Aqueous Solution Preparation, Structure, and Magnetic Properties of Nano-Granular ZnxFe3?xO4 Ferrite Films  

PubMed Central

This paper reports a simple and novel process for preparing nano-granular ZnxFe3?xO4 ferrite films (0 ? x ? 0.99) on Ag-coated glass substrates in DMAB-Fe(NO3)3-Zn(NO3)2 solutions. The deposition process may be applied in preparing other cations-doped spinel ferrite films. The Zn content x in the ZnxFe3?xO4 films depends linearly on the Zn2+ ion concentration ranging from 0.0 to 1.0 mM in the aqueous solutions. With x increasing from 0 to 0.99, the lattice constant increases from 0.8399 to 0.8464 nm; and the microstructure of the films changes from the non-uniform nano-granules to the fine and uniform nano-granules of 50–60 nm in size. The saturation magnetization of the films first increases from 75 emu/g to the maximum 108 emu/g with x increasing from 0 to 0.33 and then decreases monotonously to 5 emu/g with x increasing from 0.33 to 0.99. Meanwhile, the coercive force decreases monotonously from 116 to 13 Oe. PMID:20730079

2010-01-01

363

Preparation and antibacterial activity of Fe3O4@Ag nanoparticles  

NASA Astrophysics Data System (ADS)

Bifunctional Fe3O4@Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are present in the same particle. The superparamagnetism of Fe3O4@Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe3O4@Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe3O4@Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe3O4@Ag nanoparticles can still have antibacterial capability and can be reused.

Gong, Ping; Li, Huimin; He, Xiaoxiao; Wang, Kemin; Hu, Jianbing; Tan, Weihong; Zhang, Shouchun; Yang, Xiaohai

2007-07-01

364

Preparation of tourmaline nano-particles through a hydrothermal process and its infrared emission properties.  

PubMed

Tourmaline nano-particles were successfully prepared via a hydrothermal process using HCl as an additive. The reaction temperature (T) and the concentration of HCI (C(HCl)) had effects on the size and morphology of the tourmaline nano-particles. The optimum reaction condition was that: T = 180 degrees C and C(HCl) = 0.1 mol/l. The obtained nano-particles were spherical with the diameter of 48 nm. The far-infrared emissivity of the product was 0.923. The formation mechnism of the tourmaline nano-particles might come from the corrosion of grain boundary between the tourmaline crystals in acidic hydrothermal conditions and then the asymmetric contraction of the crystals. PMID:24734669

Xue, Gang; Han, Chao; Liang, Jinsheng; Wang, Saifei; Zhao, Chaoyue

2014-05-01

365

Preparation of silver nanoparticles in virgin coconut oil using laser ablation  

PubMed Central

Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10?8, 1.6 × 10?8, 2.4 × 10?8, respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method. PMID:21289983

Zamiri, Reza; Azmi, B Z; Sadrolhosseini, Amir Reza; Ahangar, Hossein Abbastabar; Zaidan, A W; Mahdi, M A

2011-01-01

366

Encapsulation of acetylshikonin by polyamidoamine dendrimers for preparing prominent nanoparticles.  

PubMed

Acetylshikonin (AS) has demonstrated antitumor potential. However, the development of therapeutic applications utilizing AS is inhibited by its poor solubility in water. In the present work, polyamidoamine (PAMAM) dendrimers and their PEGylated derivatives were employed to increase the solubility of AS. A distinct color transition was observed during the encapsulation of AS suggesting strong intermolecular forces between PAMAM and AS. Ultraviolet-visible, high-performance liquid chromatography, and (1)H NMR were used to verify the interaction between PAMAM and AS. The maximum amount of combined AS to each PAMAM molecule was determined. The cytotoxicity of AS nanoparticles was evaluated against leukemia (K562) and breast cancer (SK-BR-3) cell lines; the AS nanoparticles were shown to effectively inhibit tumor cells. PMID:24449188

Peng, Jianqing; Zhou, Wen; Xia, Xinyi; Qi, Xiaole; Sun, Luan; Wang, Min; Wu, Zhenghong; Li, Zhengrong

2014-04-01

367

Preparation and characterization of functional silica hybrid magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a comprehensive synthetic study is carried out and completed by a detailed characterization of hybrid particles' size and morphology, surface properties, and magnetic responses using different techniques. Depending on the mass ratio of SPIONs and the two silanes (TEOS and APTES), we were able to adjust the number of surface amino groups and tune the magnetic properties of the superparamagnetic hybrid particles.

Digigow, Reinaldo G.; Dechézelles, Jean-François; Dietsch, Hervé; Geissbühler, Isabelle; Vanhecke, Dimitri; Geers, Christoph; Hirt, Ann M.; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

2014-08-01

368

The impact of oxygen on the morphology of gas-phase prepared Au nanoparticles  

SciTech Connect

We present an easy procedure for the synthesis of single crystalline gold nanoparticles with a mean diameter of 4 nm using a DC-sputtering in an argon-oxygen gas mixture. Morphology population statistics have been determined to quantify the influence of oxygen. It is found that the particles undergo a structural transition from predominantly icosahedral to single crystalline particles with increasing amount of oxygen. Aberration-corrected high-resolution transmission electron microscopy investigation proves that likewise prepared single crystalline nanoparticles are defect and oxygen free. In contrast, the icosahedral particles prepared with pure argon show the presence of edge dislocations pointing to an energetic disfavoring already at these relatively small particle sizes. This morphology control of clean and uncovered Au nanoparticles provides a high application potential, e.g., for studying the influence of the particle morphology on plasmonic and catalytic properties.

Pohl, D.; Surrey, A.; Schultz, L. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany); TU Dresden, Institute of Condensed Matter Physics, D-01062 Dresden (Germany); Rellinghaus, B. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany)

2012-12-24

369

Synthesis and characterization of zinc sulphide nanoparticles prepared by mechanochemical route  

NASA Astrophysics Data System (ADS)

Zinc sulphide (ZnS) nanoparticles have been synthesized by the mechanochemical route. The prepared nanoparticles have been analyzed by X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy-dispersive analysis of X-rays (EDAX), Ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer and photoluminescences (PLs) spectrophotometer. The crystallite size of as prepared nanoparticles are found to be in the 4-7 nm range. EDAX spectrum confirmed the composition of ZnS sample. The value of optical band gap has been found to be in the range 4.04-4.6 eV. Room temperature photoluminescence (PL) spectrum of the samples exhibits a blue light emission under UV excitation wavelength of 280 nm. Thermal analysis studied with the help of Differential thermal analysis (DTA), Differential thermogravimetric (DTG) and thermogravimetric analysis (TGA).

Pathak, C. S.; Mandal, M. K.; Agarwala, V.

2013-06-01

370

Semiconductor nanoparticle-based hydrogels prepared via self-initiated polymerization under sunlight, even visible light  

PubMed Central

Since ancient times, people have used photosynthesized wood, bamboo, and cotton as building and clothing materials. The advantages of photo polymerization include the mild and easy process. However, the direct use of available sunlight for the preparation of materials is still a challenge due to its rather dilute intensity. Here, we show that semiconductor nanoparticles can be used for initiating monomer polymerization under sunlight and for cross-linking to form nanocomposite hydrogels with the aid of clay nanosheets. Hydrogels are an emerging multifunctional platform because they can be easily prepared using solar energy, retain semiconductor nanoparticle properties after immobilization, exhibit excellent mechanical strength (maximum compressive strength of 4.153?MPa and tensile strength 1.535?MPa) and high elasticity (maximum elongation of 2784%), and enable recyclable photodegradation of pollutants. This work suggests that functional nanoparticles can be immobilized in hydrogels for their collective application after combining their mechanical and physiochemical properties. PMID:23466566

Zhang, Da; Yang, Jinhu; Bao, Song; Wu, Qingsheng; Wang, Qigang

2013-01-01

371

A low-temperature solvothermal method to prepare hollow spherical WS 2 nanoparticles modified by TOA  

Microsoft Academic Search

Tungsten disulfide hollow spherical nanoparticles with diameters of about 100 nm modified by trioctylamine (TOA) have been successfully prepared by a solvothermal process in pyridine. For comparison, WS2 sample was also prepared without TOA modification and sheet-like pieces and their irregular aggregates were obtained. The products were characterized by X-ray power diffraction (XRD), X-ray photoelectron microscopy (XPS), transmission electron microscopy (TEM)

Jifen Wu; Xun Fu

2007-01-01

372

XRD, HRTEM, magnetic and Mössbauer studies on chemically prepared Fe 3+-doped nanoparticles of cerium oxide  

Microsoft Academic Search

Nanocrystalline samples of Fe-doped cerium oxide (Ce0.90Fe0.1O2) are prepared by sol–gel method. The precursor materials used for the synthesis are ferric nitrate and cerium nitrate. The as-prepared samples is annealed at different temperatures to obtain the sample with different particle sizes. The crystallographic phases of the nanocrystalline materials have been confirmed by X-ray diffractograms (XRD). The sizes of the nanoparticles

S. Acharya; A. Bandyopadhyay; S. Modak; S. Mukherjee; D. Das; P. K. Chakrabarti

2009-01-01

373

Preparation and Surface Layer Modification of Silicon Nanoparticles Dispersed in 2-Propanol  

NASA Astrophysics Data System (ADS)

Silicon nanoparticles dispersed in 2-propanol were prepared by using an arc plasma with gas flow method in a new designed home-made apparatus. The particles are composed of silicon crystal core covered by oxidized amorphous silicon shell. The composition of the particle surface layer can be modified by preparing the sample in different atmosphere. The particles can be also obtained with different core composition and different size which we need.

Zhu, Yong; S, Iwasaki; K, Kimura; Zhang, Li-de

1998-12-01

374

Magnetooptics and magnetic ordering in ferrite nanoparticles in glass doped with iron and rare-earth elements  

Microsoft Academic Search

Magnetic circular dichroism and X-ray diffraction were used to investigate the structure and magnetooptical properties of\\u000a nanoparticles formed in potassium-aluminum-germanium-boron glass doped with iron and rare-earth elements. It is demonstrated\\u000a that in thermally processed glass, the main magnetic phase of the formed nanoparticles is ?-Fe2O3 maghemite.

O. S. Ivanova; I. S. Edelman; R. D. Ivantsov; V. N. Zabluda; S. A. Stepanov; S. M. Zharkov; G. M. Zeer; Ya. V. Zubavichus; A. A. Veligzhanin; J. Curely

2011-01-01

375

Rare earth influence on the structural and magnetic properties of NiZn ferrites  

Microsoft Academic Search

Nanoparticles of Zn0.5Ni0.5R0.02Fe1.98O4 , with R=Y, Gd and Eu, have been prepared by the combustion method. Mössbauer spectroscopy has been used in order to analyse substitution effect on hyperfine parameters. A small increase in the hyperfine field parameters and a strong decrease of the total resonant area have been observed, with respect to the pure Ni-Zn ferrite. Curie temperatures decrease

S. E Jacobo; S Duhalde; H. R Bertorello

2004-01-01

376

A method for top down preparation of chitosan nanoparticles and nanofibers.  

PubMed

A method of top down preparation of chitosan nanoparticles and nanofibers is proposed. Chitin nanofibrils (chitin NFs) were prepared using ultrasonic assisted method from crab shells with an average diameter of 5 nm and the length less than 3 ?m as analyzed by atomic force microscopy and transmission electron microscopy. These chitin nanofibers were used as the precursor material for the preparation of chitosan nanoparticles and nanofibers. The degree of deacetylation of these prepared chitosan nanostructures were found to be approximately 98%. In addition these chitosan nanostructures showed amorphous crystallinity. Transmission electron microscopic studies revealed that chitosan nanoparticles were roughly spherical in nature and had diameters less than 300 nm. These larger particles formed through self-assembly of much smaller 25 nm particles as evidenced by the TEM imaging. The diameter and the length of the chitosan nanofibers were found to be less than 100 nm and 3 ?m respectively. It is envisaged that due to the cavitation effect, the deacetylated chitin nanofibers were broken down to small pieces to form seed particles. These seed particles can then be self-assembled to form larger chitosan nanoparticles. PMID:25498694

Wijesena, Ruchira N; Tissera, Nadeeka; Kannangara, Yasun Y; Lin, Yuan; Amaratunga, Gehan A J; de Silva, K M Nalin

2015-03-01

377

Preparation of starch-stabilized silver nanoparticles from amylose-sodium palmitate inclusion complexes  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch-stabilized silver nanoparticles were prepared from amylose-sodium palmitate complexes by first converting sodium palmitate to silver palmitate by reaction with silver nitrate and then reducing the silver ion to metallic silver. This process produced water solutions that could be dried and the...

378

Surface characterisation of dextran-coated iron oxide nanoparticles prepared by laser pyrolysis and coprecipitation  

NASA Astrophysics Data System (ADS)

The favoured mechanism of adsorption of dextran on the surface of maghemite nanoparticles (5 nm) prepared by laser pyrolysis seems to be the collective hydrogen bonding between dextran hydroxyl groups and iron oxide particle surface. After heating, the formation of a surface complex between the polysaccharide oxygen atoms and the surface iron atoms gave rise to a stronger bonding.

Carmen Bautista, M.; Bomati-Miguel, Oscar; del Puerto Morales, María; Serna, Carlos J.; Veintemillas-Verdaguer, Sabino

2005-05-01

379

Characterization of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles  

NASA Astrophysics Data System (ADS)

In this study, we compare the characteristics of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles. The magnetic nanoparticles with ~ 20 nm diameter were distributed in N-isopropylacrylamide (NIPAM) gel prepared using N,N'-methylenebisacrylamide (BIS), ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). Particle distribution and agglomeration characteristics of the prepared ferrogels were investigated using ultra small angle x-ray scattering (USAXS) and transmission electron microscopy (TEM). The ferrogel samples prepared using Fe3O4 and ?-Fe2O3 particles have similar particle distribution. The ferrogels, prepared with ?-Fe2O3 nanoparticles, however, demonstrate significantly different agglomeration characteristics compared to the ferrogels prepared using Fe3O4. In both systems, the agglomerated particles appear to be spherical, with few of those indicating chain like structures. Based on the particle concentration and sizes, the DC SQUID magnetometry data of these samples showed the magnetic moments range between 0.9 to 2.5 emu/g. Details of our results and analysis are presented.

Suthar, Kamlesh J.; Ghantasala, Muralidhar K.; Mancini, Derrick C.; Ilavsky, Jan

2009-03-01

380

Preparation and investigation of low firing temperature NiCuZn ferrites with high relative initial permeability  

NASA Astrophysics Data System (ADS)

The effects of CuO and V 2O 5 additions and the particle sizes of precursor materials on the microstructure and relative initial permeability of low firing temperature NiCuZn ferrites were investigated. It was found that additions of CuO and V 2O 5 contribute to the grain growth and densification of matrix in the sintering process, which were favorable for increase in relative initial permeability. The relative initial permeability was also strongly affected by the average particle size of precursor materials. Through using precursor materials of 0.8 ?m average particle size and adding 10 mol% CuO and 0.20 mol% V 2O 5, for the low firing temperature NiCuZn ferrite, very high relative initial permeability of 1417 can be achieved at the frequency of 1 MHz.

Yan, M.; Hu, J.; Luo, W.; Zhang, W. Y.

2006-08-01

381

PEGylated human serum albumin (HSA) nanoparticles: preparation, characterization and quantification of the PEGylation extent.  

PubMed

Modification with poly(ethylene glycol) (PEG) is a widely used method for the prolongation of plasma half-life of colloidal carrier systems such as nanoparticles prepared from human serum albumin (HSA). However, the quantification of the PEGylation extent is still challenging. Moreover, the influence of different PEG derivatives, which are commonly used for nanoparticle conjugation, has not been investigated so far. The objective of the present study is to develop a method for the quantification of PEG and to monitor the influence of diverse PEG reagents on the amount of PEG linked to the surface of HSA nanoparticles. A size exclusion chromatography method with refractive index detection was established which enabled the quantification of unreacted PEG in the supernatant. The achieved results were confirmed using a fluorescent PEG derivative, which was detected by photometry and fluorimetry. Additionally, PEGylated HSA nanoparticles were enzymatically digested and the linked amount of fluorescently active PEG was directly determined. All the analytical methods confirmed that under optimized PEGylation conditions a PEGylation efficiency of up to 0.5 mg PEG per mg nanoparticle could be achieved. Model calculations made a 'brush' conformation of the PEG chains on the particle surface very likely. By incubating the nanoparticles with fetal bovine serum the reduced adsorption of serum proteins on PEGylated HSA nanoparticles compared to non-PEGylated HSA nanoparticles was demonstrated using sodium dodecylsulfate polyacrylamide gel electrophoresis. Finally, the positive effect of PEGylation on plasma half-life was demonstrated in an in vivo study in mice. Compared to unmodified nanoparticles the PEGylation led to a four times larger plasma half-life. PMID:25789544

Fahrländer, E; Schelhaas, S; Jacobs, A H; Langer, K

2015-04-01

382

PEGylated human serum albumin (HSA) nanoparticles: preparation, characterization and quantification of the PEGylation extent  

NASA Astrophysics Data System (ADS)

Modification with poly(ethylene glycol) (PEG) is a widely used method for the prolongation of plasma half-life of colloidal carrier systems such as nanoparticles prepared from human serum albumin (HSA). However, the quantification of the PEGylation extent is still challenging. Moreover, the influence of different PEG derivatives, which are commonly used for nanoparticle conjugation, has not been investigated so far. The objective of the present study is to develop a method for the quantification of PEG and to monitor the influence of diverse PEG reagents on the amount of PEG linked to the surface of HSA nanoparticles. A size exclusion chromatography method with refractive index detection was established which enabled the quantification of unreacted PEG in the supernatant. The achieved results were confirmed using a fluorescent PEG derivative, which was detected by photometry and fluorimetry. Additionally, PEGylated HSA nanoparticles were enzymatically digested and the linked amount of fluorescently active PEG was directly determined. All the analytical methods confirmed that under optimized PEGylation conditions a PEGylation efficiency of up to 0.5 mg PEG per mg nanoparticle could be achieved. Model calculations made a ‘brush’ conformation of the PEG chains on the particle surface very likely. By incubating the nanoparticles with fetal bovine serum the reduced adsorption of serum proteins on PEGylated HSA nanoparticles compared to non-PEGylated HSA nanoparticles was demonstrated using sodium dodecylsulfate polyacrylamide gel electrophoresis. Finally, the positive effect of PEGylation on plasma half-life was demonstrated in an in vivo study in mice. Compared to unmodified nanoparticles the PEGylation led to a four times larger plasma half-life.

Fahrländer, E.; Schelhaas, S.; Jacobs, A. H.; Langer, K.

2015-04-01

383

Synthesis, characterization and magnetic properties of La 3+ added Mg–Cd ferrites prepared by oxalate co-precipitation method  

Microsoft Academic Search

Nanosized powders of Mg–Cd–La ferrite synthesized by oxalate co-precipitation method using high purity sulphates are presented. The powder has been characterized by X-ray powder diffraction (XRD), infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The phase identification of powder reveals biphasic nature of materials. The lattice constant, X-ray and physical density, porosity, crystallite size, site radii and bond length were

A. B. Gadkari; T. J. Shinde; P. N. Vasambekar

2011-01-01

384

Preparation and characterization of vanadium-doped ZnO nanoparticles for environmental application.  

PubMed

Vanadium-doped ZnO nanoparticles (ZnO:V) were prepared via flame spray pyrolysis (FSP) from a mixed aqueous solution of zinc hydroxide and vanadyl (IV) acetylacetonate. The morphological, structural and optical properties of the ZnO:V photocatalyst were characterized via transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and UV-visible diffused reflection spectrum (DRS). The photocatalytic activity of ZnO:V was evaluated via photocatalytic degradation of methylene blue (MB). The results showed that the hexagonal wurtzite-structured ZnO:V nanoparticles were successfully synthesized via FSP. The morphology of the as-prepared nanoparticles was polyhedral and non-hollow. The average diameter of ZnO:V, which was calculated from BET result, was 11.7 nm when the molar ratio of V/Zn was 0.1. The maximum decomposition of MB by the ZnO:V nanoparticles was 99.4% after 180 min under UV irradiation, whereas the decomposition of MB by the pure ZnO nanoparticles was 96.6%. PMID:21446523

Chang, Hankwon; Nikolov, Jonian; Kim, Sun-Kyung; Jang, Hee Dong; Lim, Seng; Kim, Dong-Jin

2011-01-01

385

Comparison and functionalization study of microemulsion-prepared magnetic iron oxide nanoparticles.  

PubMed

Magnetic iron oxide nanoparticles (MION) for protein binding and separation were obtained from water-in-oil (w/o) and oil-in-water (o/w) microemulsions. Characterization of the prepared nanoparticles have been performed by TEM, XRD, SQUID magnetometry, and BET. Microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) with sizes ranging from 2 to 10 nm were obtained. Study on the magnetic properties at 300 K shows a large increase of the magnetization ~35 emu/g for w/o-ME-MION with superparamagnetic behavior and nanoscale dimensions in comparison with o/w-ME-MION (10 emu/g) due to larger particle size and anisotropic property. Moringa oleifera coagulation protein (MOCP) bound w/o- and o/w-ME-MION showed an enhanced performance in terms of coagulation activity. A significant interaction between the magnetic nanoparticles and the protein can be described by changes in fluorescence emission spectra. Adsorbed protein from MOCP is still retaining its functionality even after binding to the nanoparticles, thus implying the extension of this technique for various applications. PMID:22578053

Okoli, Chuka; Sanchez-Dominguez, Margarita; Boutonnet, Magali; Järås, Sven; Civera, Concepción; Solans, Conxita; Kuttuva, Gunaratna Rajarao

2012-06-01

386

[Preparation of nanoparticles-modified silica monolith for on-column surface enhanced Raman spectroscopy].  

PubMed

A novel silica monolith modified with Ag/Au nanoparticles was prepared for the on-column surface enhanced Raman spectroscopy (SERS). The bare monolithic silica column was prepared from in-situ co-condensation of tetraethoxysilane (TMOS) and methyl trimethoxysilane (MTMS) in the presence of polyethylene glycol (PEG) via a sol-gel process in the capillary, and was chemically modified with (3-mercaptopropyl) trimethoxysilane (MTPMS), followed by immobilization of Ag/Au nanoparticles. Transmission electron microscopy (TEM) and UV-Vis spectrometer were used to collect the TEM images and the extinction spectra of the nanoparticles colloid, respectively. Scanning electron microscope (SEM) was utilized to record the morphology of the silica monolith The authros used p-aminothiophenol (PATP) as a probing molecule, and the SERS effect was investigated on Au/Ag nanoparticle-modified silica monolith under the excitation line of 633 and 532 nm, respectively. It is concluded that nanoparticle-modified silica monoliths will have broad application to the on-site detection of food and water contaminants in the field. PMID:25095424

Liu, Chan; Chen, Lei; Ren, Hua-Hua; Zhou, Ji

2014-05-01

387

Preparation of E-selectin-targeting nanoparticles and preliminary in vitro evaluation.  

PubMed

Targeted delivery aims to concentrate therapeutic agents at their site of action and thereby enhance treatment and limit side-effects. E-selectin on endothelial cells is markedly up-regulated by cytokine stimulation of inflamed and some tumoral tissues, promoting the adhesion of leukocytes and metastatic tumor cells, thus making it an interesting molecular target for drug delivery systems. We report here the preparation of targeted nanoparticles from original amphiphilic block copolymers functionalized with an analog of sialyl Lewis X (SLEx), the physiological ligand of E-selectin. Nanoparticles, prepared by nanoprecipitation, caused no significant cytotoxicity. Ligand-functionalized nanoparticles were specifically recognized and internalized better by tumor necrosis factor ? (TNF-?)-activated human umbilical vein endothelial cells (HUVECs) than control nanoparticles or HUVECs with low E-selectin expression. These nanoparticles are designed to carry the ligand at the end of a PEG spacer to improve accessibility. This system has potential for the treatment of inflammation, inhibition of tumor metastasis, and for molecular imaging. PMID:22322211

Jubeli, Emile; Moine, Laurence; Nicolas, Valérie; Barratt, Gillian

2012-04-15

388

Enhanced Oral Delivery of Docetaxel Using Thiolated Chitosan Nanoparticles: Preparation, In Vitro and In Vivo Studies  

PubMed Central

The aim of this study was to evaluate a nanoparticulate system with mucoadhesion properties composed of a core of polymethyl methacrylate surrounded by a shell of thiolated chitosan (Ch-GSH-pMMA) for enhancing oral bioavailability of docetaxel (DTX), an anticancer drug. DTX-loaded nanoparticles were prepared by emulsion polymerization method using cerium ammonium nitrate as an initiator. Physicochemical properties of the nanoparticles such as particle size, size distribution, morphology, drug loading, and entrapment efficiency were characterized. The pharmacokinetic study was carried out in vivo using wistar rats. The half-life of DTX-loaded NPs was about 9 times longer than oral DTX used as positive control. The oral bioavailability of DTX was increased to 68.9% for DTX-loaded nanoparticles compared to 6.5% for positive control. The nanoparticles showed stronger effect on the reduction of the transepithelial electrical resistance (TEER) of Caco-2 cell monolayer by opening the tight junctions. According to apparent permeability coefficient (Papp) results, the DTX-loaded NPs showed more specific permeation across the Caco-2 cell monolayer in comparison to the DTX. In conclusion, the nanoparticles prepared in this study showed promising results for the development of an oral drug delivery system for anticancer drugs. PMID:23971023

Saremi, Shahrooz; Kebriaeezadeh, Abbas; Ostad, Seyed Nasser; Atyabi, Fatemeh

2013-01-01

389

Enhanced oral delivery of docetaxel using thiolated chitosan nanoparticles: preparation, in vitro and in vivo studies.  

PubMed

The aim of this study was to evaluate a nanoparticulate system with mucoadhesion properties composed of a core of polymethyl methacrylate surrounded by a shell of thiolated chitosan (Ch-GSH-pMMA) for enhancing oral bioavailability of docetaxel (DTX), an anticancer drug. DTX-loaded nanoparticles were prepared by emulsion polymerization method using cerium ammonium nitrate as an initiator. Physicochemical properties of the nanoparticles such as particle size, size distribution, morphology, drug loading, and entrapment efficiency were characterized. The pharmacokinetic study was carried out in vivo using wistar rats. The half-life of DTX-loaded NPs was about 9 times longer than oral DTX used as positive control. The oral bioavailability of DTX was increased to 68.9% for DTX-loaded nanoparticles compared to 6.5% for positive control. The nanoparticles showed stronger effect on the reduction of the transepithelial electrical resistance (TEER) of Caco-2 cell monolayer by opening the tight junctions. According to apparent permeability coefficient (P(app)) results, the DTX-loaded NPs showed more specific permeation across the Caco-2 cell monolayer in comparison to the DTX. In conclusion, the nanoparticles prepared in this study showed promising results for the development of an oral drug delivery system for anticancer drugs. PMID:23971023

Saremi, Shahrooz; Dinarvand, Rassoul; Kebriaeezadeh, Abbas; Ostad, Seyed Nasser; Atyabi, Fatemeh

2013-01-01

390

Preparation of boron suboxide nanoparticles and their processing  

Microsoft Academic Search

Crystalline boron suboxide B6O particles with size in the range of 1.5–2 ?m and crystalline size in the range of 32–40 nm were prepared by calcination at 1400 °C for one hour of precursors prepared by wet mixing amorphous boron with water solution of B2O3 followed by evaporation and drying. The XRD analysis showed that formation of B6O started at

J Grabis; Dz Rašmane; A Kr?mi?a; A Patmalnieks

2011-01-01

391

Preparation and characterization of Tamoxifen citrate loaded nanoparticles for breast cancer therapy  

PubMed Central

Background Four formulations of Tamoxifen citrate loaded polylactide-co-glycolide (PLGA) based nanoparticles (TNPs) were developed and characterized. Their internalization by Michigan Cancer Foundation-7 (MCF-7) breast cancer cells was also investigated. Methods Nanoparticles were prepared by a multiple emulsion solvent evaporation method. Then the following studies were carried out: drug-excipients interaction using Fourier transform infrared spectroscopy (FTIR), surface morphology by field emission scanning electron microscopy (FESEM), zeta potential and size distribution using a Zetasizer Nano ZS90 and particle size analyzer, and in vitro drug release. In vitro cellular uptake of nanoparticles was assessed by confocal microscopy and their cell viability (%) was studied. Results No chemical interaction was observed between the drug and the selected excipients. TNPs had a smooth surface, and a nanosize range (250–380 nm) with a negative surface charge. Drug loadings of the prepared particles were 1.5%±0.02% weight/weight (w/w), 2.68%±0.5% w/w, 4.09%±0.2% w/w, 27.16%±2.08% w/w for NP1–NP4, respectively. A sustained drug release pattern from the nanoparticles was observed for the entire period of study, ie, up to 60 days. Further, nanoparticles were internalized well by the MCF-7 breast cancer cells on a concentration dependent manner and were present in the cytoplasm. The nucleus was free from nanoparticle entry. Drug loaded nanoparticles were found to be more cytotoxic than the free drug. Conclusion TNPs (NP4) showed the highest drug loading, released the drug in a sustained manner for a prolonged period of time and were taken up well by the MCF-7 breast cancer cell line in vitro. Thus the formulation may be suitable for breast cancer treatment due to the good permeation of the formulation into the breast cancer cells. PMID:25028549

Maji, Ruma; Dey, Niladri Shekhar; Satapathy, Bhabani Sankar; Mukherjee, Biswajit; Mondal, Subhasish

2014-01-01

392

Preparation of aminodextran-CdS nanoparticle complexes and biologically active antibody-aminodextran-CdS nanoparticle conjugates  

SciTech Connect

Stable aqueous dispersions consisting of CdS nanoparticles having modal diameters, ranging between 2 and 8 nm, were prepared with amino-derivatized polysaccharides (aminodextrans, hence abbreviated as Amdex) as the stabilizing agents. The size, stability, and luminescence intensity of such dispersions were shown to be dependent on the types of the cadmium salts and aminodextrans used, as well as on the reactant concentrations. Specifically, it was demonstrated that the degree of substitution of amino groups in the aminodextran molecules greatly affected the properties of the dispersions; i.e., with higher degree of substitution, smaller CdS particles and higher luminescence intensity were achieved. It was also shown that the Amdex-CdS nanoparticle complexes could be activated and conjugated with antibody by conventional means. Molecular weight ranges of the Amdex and their complexes with CdS nanoparticles and the purity of antibody-Amdex-CdS nanoparticle conjugates were determined by polyacrylamide gel electrophoresis combined with Coomassie blue staining of resultant gel bands. The purified conjugate of the aminodextran-CdS nanoparticle complex with anti-CD4 monoclonal antibody was mixed with a whole blood control, followed by indirect sheep antimouse antibody-phycoerythrin (SAM-PE) labeling of washed cells incubated with T4-5X-Amdex-CdS. Red blood cells were then lysed and quenched, and the resulting mixture, which was run on a flow cytometer with 488.0 nm argon ion laser excitation, suggested that the T4 antibody from the conjugate was present specifically on lymphocytes.

Sondi, I.; Siiman, O.; Koester, S.; Matijevic, E.

2000-04-04

393

Application of a new coordination compound for the preparation of AgI nanoparticles  

SciTech Connect

Graphical abstract: Silver iodide nanoparticles have been sonochemically synthesized by using silver salicylate complex, [Ag(HSal)], as silver precursor. A series of control experiments were carried out to investigate the effects of solvent, surfactant concentration, sonication time and temperature on the morphology of AgI nanostructures. - Highlights: • Silver salicylate as a new precursor was applied to fabricate ?-AgI nanoparticles. • To further decrease the particle size of AgI, SDS was used as surfactant. • The effect of preparation parameters on the particle size of AgI was investigated. - Abstract: AgI nanoparticles have been sonochemically synthesized by using silver salicylate, [Ag(HSal)], as silver precursor. To investigate the effects of solvent, surfactant concentration, sonication time and temperature on the morphology of AgI nanostructures, several experiments were carried out. The products were characterized by SEM, TEM, XRD, TGA/DTA, UV–vis, and FT-IR. Based on the experimental findings in this research, it was found that the size of AgI nanoparticles was dramatically dependent on the silver precursor, sonochemical irradiation, and surfactant concentration. Sodium dodecyl sulfate (SDS) was applied as surfactant. When the concentration of SDS was 0.055 mM, very uniform sphere-like AgI nanoparticles with grain size of about 25–30 nm were obtained. These results indicated that the high concentration of SDS could prevent the aggregation between colloidal nanoparticles due to its steric hindrance effect.

Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of)

2013-10-15

394

Preparation and evaluation of oleoyl-carboxymethy-chitosan (OCMCS) nanoparticles as oral protein carriers.  

PubMed

Oleoyl-carboxymethy chitosan (OCMCS) nanoparticles based on chitosan with different molecular weights (50, 170 and 820 kDa) were prepared by self-assembled method. The nanoparticles had spherical shape, positive surface charges and the mean diameters were 157.4, 274.1 and 396.7 nm, respectively. FITC-labeled OCMCS nanoparticles were internalized via the intestinal mucosa and observed in liver, spleen, intestine and heart following oral deliverance to carps (Cyprinus carpio). Extracellular products (ECPs) of Aeromonas hydrophila as microbial antigen was efficiently loaded to form OCMCS-ECPs nanoparticles and shown to be sustained release in PBS. Significantly higher (P < 0.05) antigen-specific antibodies were detected in serum after orally immunized with OCMCS-ECPs nanoparticles than that immunized with ECPs alone and non-immunized in control group in carps. These results implied that amphiphilic modified chitosan nanoparticles had great potential to be applied as carriers for the oral administration of protein drugs. PMID:22139537

Liu, Ya; Cheng, Xiao Jie; Dang, Qi Feng; Ma, Fang Kui; Chen, Xi Guang; Park, Hyun Jin; Kim, Bum Keun

2012-02-01

395

Chitosan-poly (lactide-co-glycolide) (CS-PLGA) nanoparticles containing metformin HCl: preparation and in vitro evaluation.  

PubMed

In this study, the preparation and in vitro characterisation of metformin HCl-loaded CS-PLGA nanoparticles (NPs) were aimed. The prepared nanoparticles (blank nanoparticles (C-1), 50 mg of metformin HCl loaded nanoparticles (C-2) and 75 mg of metformin HCl loaded nanoparticles (C-3) ranged in size from 506.67±13.61 to 516.33±16.85 nm and had surface charges of 22.57±1.21 to 32.37±0.57 mV. Low encapsulation efficiency was observed for both nanoparticle formulations due to the leakage of metformin HCl to the external medium during preparation of nanoparticles. Nanoparticle formulations showed highly reproducible drug release profiles. ~20% of metformin HCl was released within 30 minutes and approximately 98% of the loaded metformin HCl was released at 144 hours in a phosphate buffer (PB; pH 6.8). No statistically significant difference was noted between the in vitro release profiles of the nanoparticles (C-2 and C-3) containing metformin HCl. Also, nanoparticles were characterised using FT-IR and DSC. PMID:25362616

Gundogdu, Nuran; Cetin, Meltem

2014-11-01

396

Role of interparticle interactions on the magnetic behavior of Mg(0.95)Mn(0.05)Fe(2)O(4) ferrite nanoparticles.  

PubMed

We present here a detailed investigation of the static and dynamic magnetic behavior of a Mg(0.95)Mn(0.05)Fe(2)O(4) spinel ferrite nanoparticle system synthesized by high-energy ball milling of almost identical particle size distributions ([Formula: see text], 5.1 and 6.0 ± 0.6 nm). The samples were characterized by using x-ray diffraction, Mössbauer spectroscopy, dc magnetization and frequency dependent real ?(')(T) and imaginary ?('')(T) parts of ac susceptibility measurements. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization have been recorded in a low field and show a behavior typical of superparamagnetic particles above a temperature of 185 ± 5 K, which is further supported from the temperature dependent Mössbauer measurements. The fact that the blocking temperature calculated from the ZFC magnetization and Mössbauer data are almost similar gives a clear indication of the interparticle interactions among these nanoparticle systems. This is further supported from the FC magnetization curves, which are almost flat below a certain temperature (less than the blocking temperature), as compared with the monotonically increasing behavior characteristics of non-interacting superparamagnetic particles. A shift of the blocking temperature with increasing frequency was observed in the real ?(')(T) and imaginary ?('')(T) parts of the ac susceptibility measurements. The analysis of the results shows that the data fit well with the Vogel-Fulcher law, whereas trials using the Neel-Brown and power law are unproductive. The role of magnetic interparticle interactions on the magnetic behavior, namely superparamagnetic relaxation time and magnetic anisotropy, are discussed. PMID:21694305

Sharma, S K; Kumar, Ravi; Kumar, Shalendra; Knobel, M; Meneses, C T; Siva Kumar, V V; Reddy, V R; Singh, M; Lee, C G

2008-06-11

397

Preparation and magnetic properties of spindle porous iron nanoparticles  

SciTech Connect

Spindle porous iron nanoparticles were firstly synthesized by reducing the pre-synthesized hematite ({alpha}-Fe{sub 2}O{sub 3}) spindle particles with hydrogen gas. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms and vibrating sample magnetometry (VSM). A lattice shrinkage mechanism was employed to explain the formation process of the porous structure, and the adsorbed phosphate was proposed as a protective shell in the reduction process. N{sub 2} adsorption/desorption result showed a Brunauer-Emmett-Teller (BET) surface area of 29.7 m{sup 2}/g and a continuous pore size distribution from 2 nm to 100 nm. The magnetic hysteresis loop of the synthesized iron particles showed a saturation magnetization of 84.65 emu/g and a coercivity of 442.36 Oe at room temperature.

Lv Baoliang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Yao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Wu Dong; Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China)

2009-05-06

398

Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity  

NASA Astrophysics Data System (ADS)

The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual.

Ayaz Ahmed, Khan Behlol; Subramanian, Swetha; Sivasubramanian, Aravind; Veerappan, Ganapathy; Veerappan, Anbazhagan

2014-09-01

399

Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity.  

PubMed

The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual. PMID:24762573

Ayaz Ahmed, Khan Behlol; Subramanian, Swetha; Sivasubramanian, Aravind; Veerappan, Ganapathy; Veerappan, Anbazhagan

2014-09-15

400

Double crosslinked interpenetrated network in nanoparticle form for drug targeting--preparation, characterization and biodistribution studies.  

PubMed

The development of polymer nanosystems able to target and control/sustain the drug delivery is still considered an important desideratum in pharmaceutical research. The present study reports the preparation of nanoparticles based on chitosan and gelatin, using a reverse emulsion-double crosslinking (ionic followed by covalent one) technique. The nanoparticles structural and morphological characteristics (diameter and size distribution), their swelling capacity in aqueous media of different pH (4 and 7.4) and their ability to include and release poorly water-soluble drugs were seen to be influenced by the composition of the polymer mixture and by the surfactants concentration. Also, nanoparticles biodistribution after intraperitoneal or intravenous administration was evaluated by polymer marking with fluorescein. Particles ability to penetrate different organs (liver, heart, lungs, and less brain, gums, testicles) was increased when injected intravenously. PMID:22721854

J?tariu Cadinoiu, Anca N; Holban, Mihaela N; Peptu, C?t?lina A; Sava, Anca; Costuleanu, Marcel; Popa, Marcel

2012-10-15

401

Preparation of bicontinuous mesoporous silica and organosilica materials containing gold nanoparticles by co-synthesis method  

SciTech Connect

Catalytic activities of gold strongly depend on its particle size. It is necessary to have homogeneous distributions of small gold nanoparticles with diameters between 2 and 5 nm for excellent catalytic activities. In this study, gold-containing mesoporous silica materials were prepared by a co-synthesis method. The essence of this sol-gel co-synthesis method is to combine together neutral surfactant template synthesis of mesoporous silica materials with the introduction of metal ions via bifunctional silane ligands, so that the formation of mesostructures and metal-ion doping occur simultaneously. The formation of gold nanoparticles with size less than 5 nm inside mesoporous materials (HMS, MSU, and PMO) has been achieved by this co-synthesis sol-gel process. In addition, the effects of post-treatments, such as calcination and reduction, on pore structures and nanoparticle size distributions were also investigated.

Lee, Byunghwan [Korea Institute of Industrial Technology, ChonAn, Korea; Zhu, Haoguo [ORNL; Zhang, Zongtao [ORNL; Overbury, Steven {Steve} H [ORNL; Dai, Sheng [ORNL

2004-01-01

402

Formulation/Preparation of Functionalized Nanoparticles for In Vivo Targeted Drug Delivery  

NASA Astrophysics Data System (ADS)

Targeted cancer therapy allows the delivery of therapeutic agents to cancer cells without incurring undesirable side effects on the neighboring healthy tissues. Over the past decade, there has been an increasing interest in the development of advanced cancer therapeutics using targeted nanoparticles. Here we describe the preparation of drug-encapsulated nanoparticles formulated with biocompatible and biodegradable poly( d, l-lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) copolymer and surface functionalized with the A10 2-fluoropyrimidine ribonucleic acid aptamers that recognize the extracellular domain of prostate-specific membrane antigen (PSMA), a well-characterized antigen expressed on the surface of prostate cancer cells. We show that the self-assembled nanoparticles can selectively bind to PSMA-targeted prostate cancer cells in vitro and in vivo. This formulation method may contribute to the development of highly selective and effective cancer therapeutic and diagnostic devices.

Gu, Frank; Langer, Robert; Farokhzad, Omid C.

403

Surface-modified antibacterial TiO 2/Ag + nanoparticles: Preparation and properties  

NASA Astrophysics Data System (ADS)

Studies were performed on surface modification of antibacterial TiO 2/Ag + nanoparticles by grafting ?-aminopropyltriethoxysilane (APS). The interfacial structure of the modified particles was characterized by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis. The thickness of the surface layer was determined by using Auger electron spectroscopy (AES). The results show that APS is chemically bonded to the surface of antibacterial TiO 2/Ag + nanoparticles. Furthermore, the modified particles were mixed in PVC to prepare composites whose antibacterial property was investigated. The results suggest that surface modification has no negative effect on antibacterial activity of TiO 2/Ag + nanoparticles and PVC-TiO 2/Ag + composites exhibits good antibacterial property.

Cheng, Qilin; Li, Chunzhong; Pavlinek, Vladimir; Saha, Petr; Wang, Huanbing

2006-04-01

404

Preparation and heat transfer properties of nanoparticle-in-transformer oil dispersions as advanced energy-efficient coolants  

Microsoft Academic Search

Three kinds of nanofluids are prepared by dispersing Al2O3 and AlN nanoparticles-in-transformer oil. The thermal conductivity of the nanoparticle–oil mixtures increases with particle volume fraction and thermal conductivity of the solid particle itself. The AlN nanoparticles at a volume fraction of 0.5% can increase the thermal conductivity of the transformer oil by 8% and the overall heat transfer coefficient by

C. Choi; H. S. Yoo; J. M. Oh

2008-01-01

405

An investigation of structural, magnetic and microwave properties of strontium hexaferrite nanoparticles prepared by a sol-gel process with doping SN and Tb  

NASA Astrophysics Data System (ADS)

The goal of this study was to investigate the structural, magnetic and microwave properties of Sn4+-Tb4+ substituted strontium ferrite with chemical formula of SrFe12-x(SnTb)x/2O19(x=0-2)(in the step of 0.5) nanoparticles prepared by the sol-gel method. In order to study the formation of hexaferrite phase, X-ray diffraction analysis was carried out and it was discovered that a single magnetoplumbite was formed. A field emission scanning microscopy was hired to explore the morphology and particle size of nanopowders. Fourier-transform infrared was employed to confirm different bond modes which were structured. A vibrating-sample magnetometer was used to investigate the magnetic characteristics of the prepared samples. The results showed that with an increase in substitutions, Sn-Tb, magnetization and remanence were increased along with a decrease in coercivity. A vector network analyzer was utilized to scrutinize the microwave properties. The resultant data showed a striking achievement with high reflection loss value and a wide bandwidth in the range of 20-26 GHz.

Jamalian, Majid

2015-03-01

406

Preparation and characterization of coenzyme Q 10-loaded PMMA nanoparticles by a new emulsification process based on microfluidization  

Microsoft Academic Search

A microfluidization and solvent evaporation method was employed to prepare poly(methyl methacrylate) (PMMA) nanoparticles containing coenzyme Q10. Dynamic light scattering and transmission electron microscopy showed that the mean diameter of the nanoparticles was highly influenced by the kind of surfactants used and the recycling number of the microfluidization process. Particles with sizes from 40 to 260 nm and low polydispersities

Sun Sang Kwon; Yoon Sung Nam; Jong Suk Lee; Bong Seok Ku; Sang Hoon Han; Jang Young Lee; Ih Seop Chang

2002-01-01

407

Film electrode prepared from oppositely charged silicate submicroparticles and carbon nanoparticles for selective dopamine sensing.  

PubMed

Film electrodes prepared from oppositely charged silicate submicroparticles and carbon nanoparticles was applied for selective dopamine sensing. Mesoporous silicate submicroparticles with tetraalkylammonium functionalities were prepared by sol-gel method. They were immobilised on an indium tin oxide film surface together with phenylsulphonated carbon nanoparticles by layer-by-layer method: alternative immersion into their suspensions. As it is shown by scanning electron microscopy the obtained film is composed of silicate submicroparticles covered by carbon nanoparticles. The nanoparticulate film is stable and its electroactive surface is significantly larger than substrate. Accumulation of redox active cations indicates that only fraction charged functionalities of carbon nanoparticles are employed in film formation. The obtained electrode exhibits catalytic properties towards dopamine oxidation and its interferences as ascorbic acid, uric acid and acetaminophen. This allows for selective determination of tenth micromolar concentration of dopamine in the presence of these interferences at milimolar level. The detection limit and linear range were determined to 0.1 × 10?? mol dm?³ and 0.3-18 × 10?? mol dm?³ respectively. PMID:21641787

Celebanska, Anna; Tomaszewska, Dorota; Lesniewski, Adam; Opallo, Marcin

2011-07-15

408

Preparation of boron suboxide nanoparticles and their processing  

NASA Astrophysics Data System (ADS)

Crystalline boron suboxide B6O particles with size in the range of 1.5-2 ?m and crystalline size in the range of 32-40 nm were prepared by calcination at 1400 °C for one hour of precursors prepared by wet mixing amorphous boron with water solution of B2O3 followed by evaporation and drying. The XRD analysis showed that formation of B6O started at 1350 °C and well crystallized powder was obtained at 1400 °C at ambient pressure. The synthesis temperature corresponded to the literature data but formation process was three times quicker. Decrease of molar ratio B/B2O3 from 16 to 14 in the precursor mixture reduced nonstoichiometry of prepared B6O although simultaneously it increased admixture of B2O. The characteristic shape of the particles was starlike plates. During the spark plasma sintering process, the densification of boron suboxide started at 1500 °C and fully dense bodies (98%) were fabricated at 1900 °C within five minutes.

Grabis, J.; Rašmane, Dz; Krbar umi?a, A.; Patmalnieks, A.

2011-12-01

409

Preparation and characterization of TiO 2-cationic hybrid nanoparticles as electrophoretic particles  

NASA Astrophysics Data System (ADS)

The hybrid nanoparticles (TiO 2-HNPs) with TiO 2 nanoparticles as core and with poly( N, N-dimethylaminoethyl methacrylate- co-methyl methacrylate) by using triallylamine as cross-linking agent as shell were firstly prepared via atom transfer radical polymerization (ATRP) in methanol. Then the hybrid nanoparticles with positive charge were produced by the quaternization with methyl iodide as quaternization reagent so as to endow them with greater electrophoretic mobility. The cationic hybrid nanoparticles (TiO 2-CHNPs) were studied by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) measurements. The results indicate that the cationic polymer is successfully grafted on the surface of the TiO 2 nanoparticles. The particle size of TiO 2-CHNPs is about 150 nm and the polydispersity index (PDI) is 0.307. The zeta potential, the contrast ratio of white state to dark state and response time of TiO 2-CHNPs are +16.8 mV, 30 and 3 s, respectively, which show the potential application prospect in the development of electrophoretic ink.

Li, Jingjing; Deng, Liandong; Xing, Jinfeng; Dong, Anjie; Li, Xianggao

2012-01-01

410

[Preparation and characterization of magnetic nano-particles with radiofrequency-induced hyperthermia for cancer treatment].  

PubMed

Mn0.5Zn0.5Fe2O4 nano-particles were prepared by the chemical co-precipitation, their characteristics were observed with transmission electron microscope (TEM), X-ray diffractometer (XRD) and thermal analysis system, and etc. The temperature changes of the nano-particles of Mn0.5Zn0.5Fe2O4 and its magnetic fluid explored in radiofrequency(RF,200 KHz, 4 KW) were measured. The proliferation ratio of L929 cells cultured in soak of Mn0.5Zn0.5Fe2O4 nano-particles were observed. The experiment indicates that the magnetic particles were about 40 nm diameter in average, round, had strong magnetism, and were proved to be consistent with the standard data of chart of XRD. Its magnetic fluid exposed to RF could be heated up to temperature range from 40 degrees C to 51 degrees C due to the amount of the magnetic nano-particles and intensity of the alternating magnetic field. Magnetic nano-particles were found to have no obvious cytotoxicity to L929 cells. PMID:17002113

Fan, Xiangshan; Zhang, Dongsheng; Zheng, Jie; Gu, Ning; Ding, Anwei; Jia, Xiupeng; Qing, Hongyun; Jin, Liqiang; Wan, Meiling; Li, Qunhui

2006-08-01

411

Nanoparticles synthesized from soy protein: preparation, characterization, and application for nutraceutical encapsulation.  

PubMed

Nanoparticles were synthesized from soy protein, one of the most abundant and widely utilized plant proteins, for nutraceutical and drug encapsulation. The preparation process consisted of dispersion, desolvation, drug incorporation, cross-linking, and evaporation. The role of each procedure in the formation of nanoparticles was systematically investigated by means of particle size, size distribution, and zeta potential as well as morphology observation. Curcumin as a model drug was encapsulated successfully into the nanoparticles, evidenced by Fourier transform infrared spectroscopy and X-ray diffraction patterns. The average size of the curcumin-loaded nanoparticles was 220.1 to 286.7 nm, and their zeta potential was around -36 mV. The highest encapsulation efficiency and loading efficiency achieved were 97.2% and 2.7%, respectively. The release of curcumin in phosphate buffer saline followed a biphasic pattern. Possible mechanisms of the formation of soy protein nanoparticles as well as the incorporation of curcumin were discussed based on the data obtained from this study. PMID:22352467

Teng, Zi; Luo, Yangchao; Wang, Qin

2012-03-14

412

Preparation and optical characterization of core-shell bi-metallic nanoparticles  

NASA Astrophysics Data System (ADS)

Chemical approaches allow for the synthesis of highly defined metal heterostructures, such as core-shell nanoparticles. As the material of metal nanoparticles determines the plasmon resonance-induced absorption band, the control of particle composition results in control of the absorption maximum position. Metal deposition on gold or silver nanoparticles was used to prepare core-shell particles with modified optical properties with respect to monometal nanoparticles. UV-vis spectroscopy on solution-grown and immobilized particles was conducted as ensemble measurements, complemented by single particle spectroscopy of selected structures. Increasing layers of a second metal, connected to a dominant contribution of the shell material to the extinction spectrum, lead to a shift in the absorption band. The extent of shell growth could be controlled by reaction time or the concentration of either the metal salt or the reducing agent. Additional to the optical characterization, the utilization of AFM, SEM and TEM yielded important information about the ultrastructure of the nanoparticle complexes.

Steinbrück, Andrea; Csáki, Andrea; Festag, Grit; Schüler, Thomas; Fritzsche, Wolfgang

2007-07-01

413

Preparation and Physicochemical Properties of 10-Hydroxycamptothecin (HCPT) Nanoparticles by Supercritical Antisolvent (SAS) Process  

PubMed Central

The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO2 and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT. PMID:21731466

Zhao, Xiuhua; Zu, Yuangang; Jiang, Ru; Wang, Ying; Li, Yong; Li, Qingyong; Zhao, Dongmei; Zu, Baishi; Zhang, Baoyou; Sun, Zhiqiang; Zhang, Xiaonan

2011-01-01

414

Chitosan-lignosulfonates sono-chemically prepared nanoparticles: characterisation and potential applications.  

PubMed

Due to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates were developed for the first time for cosmetic and biomedical applications. The ability of lignosulfonates to act as a counter polyion for stabilisation of chitosan particles, generated using high intensity ultrasound, was investigated. Several conditions for particles preparation were tested and optimised and the resulting nanoparticles were comprehensively characterised by measuring particle size, zeta potential and polydispersity index. The pH of chitosan solution, sonication time and the presence of an adequate surfactant, poloxamer 407, were determinant factors on the development of smaller particles with low polydispersity index (an average particle size of 230 nm was obtained at pH 5 after 8 min of sonication). The beneficial effects of lignosulfonates complex on chitosan nanoparticles were further characterised. Greater stability to lysozyme degradation, biocompatibility with human cells and antimicrobial activity was found upon lignosulfonates incorporation into chitosan nanoparticles. Furthermore, these particles were able to incorporate a hydrophilic model protein - RNase A. A burst release was observed when nanoparticles were loaded with low amount of protein while with high protein content, a sustained release was found, suggesting that the protein cargo maybe loaded both at the surface as in the bulk of the particle, depending on the concentration of drug incorporated. PMID:23178385

Kim, Suyeon; Fernandes, Margarida M; Matamá, Teresa; Loureiro, Ana; Gomes, Andreia C; Cavaco-Paulo, Artur

2013-03-01

415

Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles  

PubMed Central

Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

Jeong, Lim; Park, Won Ho

2014-01-01

416

Enhancing encapsulation efficiency of highly water-soluble antibiotic in poly(lactic-co-glycolic acid) nanoparticles: Modifications of standard nanoparticle preparation methods  

Microsoft Academic Search

Effective encapsulations of drugs that are highly soluble in both water and organic solvents are notoriously difficult to achieve using standard nanoparticle preparation methods, such as nanoprecipitation (NPC), single (ESE), and double (DESE) emulsification-solvent-evaporation methods. Modifications of the standard preparation methods are therefore needed to enhance encapsulation efficiency of this group of drugs. The present work investigates the feasibility of

Wean Sin Cheow; Kunn Hadinoto

2010-01-01

417

Controlled oxidation of FeCo magnetic nanoparticles to produce faceted FeCo/ferrite nanocomposites for rf heating applications  

E-print Network

for rf heating applications K. N. Collier,1,2 N. J. Jones,1 K. J. Miller,1 Y. L. Qin,1 D. E. Laughlin,1 for polydisperse FeCo magnetic nanoparticles MNPs synthesized using an induction plasma torch. X-ray diffraction the FeCo core and oxide shell. We show HRTEM images of MNP chaining and compare the rf heating of samples

Laughlin, David E.

418

Colloidal silver nanoparticle gradient layer prepared by drying between two walls of different wettability.  

PubMed

A one-dimensional silver (Ag) nanoparticle gradient layer is prepared from an aqueous colloidal solution upon a polystyrene (PS) coated silicon (Si) substrate. For preparation two walls of different wettability are used. The 40 nm PS-layer exhibits a locally constant film thickness due to the strong roughness correlation with the underlying Si-substrate and is less wettable as compared to the glass plate placed above. The Ag nanoparticles have a triangular prism-like shape. The structural characterization of the obtained complex gradient formed by drying is performed with microbeam grazing incidence small-angle x-ray scattering based on compound refractive lenses. Due to the adsorption from aqueous solution in the selective geometry a double gradient type structure defined by two areas with characteristic lateral lengths and a cross-over regime between both is observed. PMID:21828460

Roth, S V; Kuhlmann, M; Walter, H; Snigirev, A; Snigireva, I; Lengeler, B; Schroer, C G; Burghammer, M; Riekel, C; Müller-Buschbaum, P

2009-07-01

419

Facile preparation of silver nanoparticle films as an efficient surface-enhanced Raman scattering substrate  

NASA Astrophysics Data System (ADS)

Here, we report a new and facile method to prepare silver nanoparticles (Ag NPs) film for surface-enhanced Raman scattering (SERS)-based sensing. The porous Ni foam was used as a template to generate high quality of Ag NPs by seed-mediated growth of metallic nanoparticles. The preparation process is very economic and environment-friendly, can achieve the recovery of the raw materials. We found that the type of silver-plating solution and the growth time are two key factors to determine the magnitude of SERS signal enhancement. Using rhodamine 6G (R6G) and 4-animothiophenol (4-ATP) as probe molecules, the created Ag NP films exhibited relatively high enhancement ability, good stability, and well reproducibility. The synthesized SERS-active substrate was further used to detect melamine molecules, an illegal additive in infant milk powder, and the limitation of detection can reach 1 ?M.

Sun, Yujing; Zhang, Yue; Shi, Yan; Xiao, Xianping; Dai, Haichao; Hu, Jingting; Ni, Pengjuan; Li, Zhuang

2013-10-01

420

Study of Structural and Dielectric Properties of Copper Oxide Nanoparticles Prepared by Wet Chemical Precipitation Method  

NASA Astrophysics Data System (ADS)

We report the synthesis of copper oxide (CuO) nanoparticles prepared by wet chemical precipitation method. The structural and dielectric properties are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and complex impedance spectroscopy as a function of frequencies from 40 KHz to 100 KHz in the range of temperatures (308-393K). Maximum value of dielectric constants are found to be in the order of 106 which increases with increase in temperatures. From XRD data it is found that the particle size increases with increase in calcination temperatures. SEM with energy dispersive X-ray fluorescence spectrometer (EDX) results show that only CuO is present in the prepared sample. The selected area electron diffraction (SAED) pattern by TEM shows that uniform size distributions of CuO nanoparticles are present in the sample.

Siddique, Kibriya; Nath, Bhabesh Kumar; Karmakar, Sanjib

2013-01-01