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1

Magnetic nanocomposites: Preparation and characterization of Co-ferrite nanoparticles  

Microsoft Academic Search

Cobalt ferrite nanoparticles, CoFe2O4, are one of the important spinel ferrites because of their high cubic magnetocrystalline anisotropy, high coercivity and moderate saturation magnetization. CoFe2O4 nanoparticles have been known to be a photomagnetic material which shows an interesting light induced coercivity change. In this study, various preparation techniques were used to produce cobalt ferrite nanoparticles: (i) ball milling of a

M. H. Khedr; A. A. Omar; S. A. Abdel-Moaty

2

Magnetic nanocomposites: Preparation and characterization of Co-ferrite nanoparticles  

Microsoft Academic Search

Cobalt ferrite nanoparticles, CoFe2O4, are one of the important spinel ferrites due to their high cubic magnetocrystalline anisotropy, high coercivity and moderate saturation magnetization. CoFe2O4 nanoparticles have been known to be a photomagnetic material which shows an interesting light induced coercivity change. In this study, various preparation techniques were used to produce cobalt ferrite nanoparticles namely, (i) ball milling of

M. H. Khedr; A. A. Omar; S. A. Abdel-Moaty

2006-01-01

3

Preparation of cobalt-ferrite nanoparticles within a biopolymer template  

NASA Astrophysics Data System (ADS)

Using an in-situ co-precipitation reaction from solid dissolutions of stoichiometric amounts of Fe (III) and Co (II) inorganic salts, it was prepared highly loaded nanocomposites (as high as 75% w/w) of cobalt-ferrite nanoparticles within a chitosan matrix, with particle size of about 7 nm, narrow particle size distribution and superparamagnetic character. Nanocomposite samples were characterized by high resolution transmission electron microscopy (HRTEM), UV-vis spectrometry and magnetic measurements by SQUID, using magnetization-field dependent, M(H), and magnetization-temperature dependent, M(T), studies.

Garza, Marco; González, Virgilio; Torres-Castro, Alejandro; Hinojosa, Moisés; Ortíz, Ubaldo

2008-03-01

4

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

5

Physical and magnetic properties of highly aluminum doped strontium ferrite nanoparticles prepared by auto-combustion route  

E-print Network

Physical and magnetic properties of highly aluminum doped strontium ferrite nanoparticles prepared-Hexaferrite Al doped Sr-Ferrite High Coercivity Ferrite a b s t r a c t Highly Al3þ ion doped nanocrystalline Sr microscope show growth of needle shaped ferrites with high aspect ratio at Al3þ ion content exceeding xZ2. Al

Liu, J. Ping

6

Barium ferrite nanoparticles prepared directly by aerosol pyrolysis  

Microsoft Academic Search

BaFe12O19 nanoparticles, 10 nm in diameter, have been obtained by combination of two methods, the citrate precursor and the aerosol pyrolysis technique. For the first time, well-crystallised barium ferrite particles were obtained by pyrolysis of an aerosol, produced by ultrasonic frequency spraying of a barium iron citrate aqueous solution, in a tubular furnace at 1000°C, without further heat treatment. The

T González-Carreño; M. P Morales; C. J Serna

2000-01-01

7

Photocatalytic ozonation of dyes using copper ferrite nanoparticle prepared by co-precipitation method  

Microsoft Academic Search

In this paper, photocatalytic ozonation of dyes with copper ferrite (CuFe2O4) nanoparticle (CF nanoparticle) prepared by co-precipitation method was investigated. Reactive Red 198 (RR198) and Reactive Red 120 (RR120) were used as dye models. The characteristics of CF nanoparticle were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). UV–Vis and ion chromatography (IC) analyses were employed to

Niyaz Mohammad Mahmoodi

2011-01-01

8

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

9

Mn–Zn ferrite nanoparticles for ferrofluid preparation: Study on thermal–magnetic properties  

Microsoft Academic Search

Mn1?xZnxFe2O4 (with x varying from 0.1 to 0.5) ferrite nanoparticles used for ferrofluid preparation have been prepared by chemical co-precipitation method and characterized. Characterization techniques like elemental analysis by atomic absorption spectroscopy and spectrophotometry, thermal analysis using simultaneous TG-DTA, XRD, TEM, VSM and Mossbauer spectroscopy have been utilized. The final cation contents estimated agree with the initial degree of substitution.

R. Arulmurugan; G. Vaidyanathan; S. Sendhilnathan; B. Jeyadevan

2006-01-01

10

Magnetocaloric effect in ferrite nanoparticles  

Microsoft Academic Search

A comparative study of the magnetocaloric effect (MCE) is reported in two different types of chemically synthesized magnetic nanoparticle systems—cobalt ferrite and manganese zinc ferrite with mean size around 5 and 15nm, respectively. While CoFe2O4 nanoparticles were synthesized using co-precipitation, the Mn0.68Zn0.25Fe2.07O4 (MZFO) nanoparticles were prepared by reverse micelle technique using AOT as surfactant. Our results indicate that the change

P. Poddar; J. Gass; D. J. Rebar; S. Srinath; H. Srikanth; S. A. Morrison; E. E. Carpenter

2006-01-01

11

Preparation of magnetic spinel ferrite core\\/shell nanoparticles: Soft ferrites on hard ferrites and vice versa  

Microsoft Academic Search

Hard\\/soft CoFe2O4\\/ZnFe2O4 and soft\\/hard ZnFe2O4\\/CoFe2O4 core\\/shell nanoparticles were prepared by combining high-temperature thermolysis of metal oxide precursors with seed-mediated growth. Magnetic properties of the core\\/shell nanoparticles were compared to those of individual CoFe2O4 and ZnFe2O4 nanoparticles of similar size prepared by the same method. The structure of the core\\/shell materials was established using a combination of X-ray and neutron powder

Ombretta Masala; Darin Hoffman; Nalini Sundaram; Katharine Page; Thomas Proffen; Gavin Lawes; Ram Seshadri

2006-01-01

12

Preparation and characterization of complex ferrite nanoparticles by a polymer-pyrolysis route  

Microsoft Academic Search

The polymer-pyrolysis route used in this work was to synthesize the copolymeric precursor of the mixed metallic ions and then\\u000a to pyrolyze the precursor into complex spinel ferrite nanoparticles. Thermogravimetric analysis (TGA) showed that the complex\\u000a ferrite nanoparticles could be obtained by calcination of their precursors at 500°C. The structures, elemental analyses and\\u000a particle morphology of the as-calcined products were

Xian-Ming Liu; Shao-Yun Fu; Hong-Mei Xiao; Lu-Ping Zhu

2007-01-01

13

Mn Zn ferrite nanoparticles for ferrofluid preparation: Study on thermal magnetic properties  

NASA Astrophysics Data System (ADS)

Mn 1-xZn xFe 2O 4 (with x varying from 0.1 to 0.5) ferrite nanoparticles used for ferrofluid preparation have been prepared by chemical co-precipitation method and characterized. Characterization techniques like elemental analysis by atomic absorption spectroscopy and spectrophotometry, thermal analysis using simultaneous TG-DTA, XRD, TEM, VSM and Mossbauer spectroscopy have been utilized. The final cation contents estimated agree with the initial degree of substitution. The Curie temperature ( T) and particle size decrease with the increase in zinc substitution. In the case of particles with higher zinc concentration, both ferrimagnetic nanoparticles and particles exhibiting superparamagnetic behavior at room temperature are present. In addition, some of the results obtained by slightly altering the preparation condition are also discussed. The precipitated particles were used for ferrofluid preparation. The fine particles were suitably dispersed in heptane using oleic acid as the surfactant. The volatile nature of the carrier chosen helps in altering the number concentration of the magnetic particles in a ferrofluid. Magnetic properties of the fine particles and ferrofluids are discussed. Ferrofluids having Mn 0.5Zn 0.5Fe 2O 4 particles can be used for the energy conversion application utilizing the magnetically induced convection for thermal dissipation.

Arulmurugan, R.; Vaidyanathan, G.; Sendhilnathan, S.; Jeyadevan, B.

2006-03-01

14

Preparation of NiCuZn ferrite nanoparticles from chemical co-precipitation method and the magnetic properties after sintering  

Microsoft Academic Search

NiCuZn ferrite nanoparticles with composition of NixCuyZn1?x?yFe2O4 (where x=0.15–0.5 and y=0–0.35) were prepared by the chemical co-precipitation method at various reaction temperatures with a final pH value of 12. From the analysis of X-ray diffraction patterns, the nanocrystalline NiCuZn ferrite particles could be obtained at pH=12 and reaction temperature between 30 and 90°C with the reaction time of 6h. The

Wei-Chih Hsu; S. C Chen; P. C Kuo; C. T Lie; W. S Tsai

2004-01-01

15

Structure of manganese zinc ferrite spinel nanoparticles prepared with co-precipitation in reversed microemulsions  

Microsoft Academic Search

The structure of Mn0.5Zn0.5Fe2O4 spinel ferrite nanoparticles is studied as a function of their size and the experimental conditions of their synthesis using\\u000a X-ray absorption spectroscopy. The nanoparticles of different sizes down to approximately 2 nm and with a narrow size distribution\\u000a were synthesized using co-precipitation in reverse microemulsions. Simultaneous refinement of the X-ray absorption fine structure\\u000a (EXAFS) of three constituting

Darko Makovec; Alojz Kodre; Iztok Ar?on; Miha Drofenik

2009-01-01

16

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

17

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

Microsoft Academic Search

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

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

2010-01-01

18

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

19

Synthesis, structural investigation and magnetic properties of Zn2+ substituted cobalt ferrite nanoparticles prepared by the sol-gel auto-combustion technique  

NASA Astrophysics Data System (ADS)

Structural morphology and magnetic properties of the Co1-xZnxFe2O4 (0.0?x?1.0) spinel ferrite system synthesized by the sol-gel auto-combustion technique using nitrates of respective metal ions have been studied. The ratio of metal nitrates to citric acid was taken at 1:3. The as prepared powder of cobalt zinc ferrite was sintered at 600 °C for 12 h after TG/DTA thermal studies. Compositional stoichiometry was confirmed by energy dispersive analysis of the X-ray (EDAX) technique. Single phase cubic spinel structure of Co-Zn nanoparticles was confirmed by XRD data. The average crystallite size (t), lattice constant (a) and other structural parameters of zinc substituted cobalt ferrite nanoparticles were calculated from XRD followed by SEM and FTIR. It is observed that the sol-gel auto-combustion technique has many advantages for the synthesis of technologically applicable Co-Zn ferrite nanoparticles. The present investigation clearly shows the effect of the synthesis method and possible relation between magnetic properties and microstructure of the prepared samples. Increase in nonmagnetic Zn2+ content in cobalt ferrite nanoparticles is followed by decrease in nB, Ms and other magnetic parameters. Squareness ratio for the Co-ferrite was 1.096 at room temperature.

Raut, A. V.; Barkule, R. S.; Shengule, D. R.; Jadhav, K. M.

2014-05-01

20

Magnetic heating by cobalt ferrite nanoparticles  

Microsoft Academic Search

In the quest for suitable materials for hyperthermia we explored the preparation and properties of nanoparticles of Co ferrite. The material was produced by coprecipitation from water solution of Co and Fe chlorides and afterwards annealed at 400, 600 and 800 °C. The resulting particles were characterized by XRD, TEM, Mössbauer spectroscopy, and dc and ac magnetometry. The heating experiments

M. Veverka; P. Veverka; O. Kaman; A. Lancok; K. Záveta; E. Pollert; K. Knízek; J. Bohácek; M. Benes; P. Kaspar; E. Duguet; S. Vasseur

2007-01-01

21

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

22

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

23

Magnetization of sol gel prepared zinc ferrite nanoparticles: Effects of inversion and particle size  

NASA Astrophysics Data System (ADS)

Nanoparticles of ZnFe 2O 4 have been prepared by using sol-gel method in two different mediums (acidic and basic) in order to observe the influence of the medium on the magnetic properties of the obtained nanoparticles. X-ray diffraction and Mössbauer studies of these samples show the presence of single-phase spinel structure. The average size of the particles as determined by X-ray diffraction increases with the annealing temperature from 18 to 52 nm. With the increase in particle size, magnetization decreases while the magnetization blocking temperature increases. Magnetization studies show that the samples prepared in basic medium have more ferrimagnetic nature as compared to those prepared in acidic medium. We understand this increase in magnetization as reflective of the increased degree of inversion (transfer of Fe 3+ ions from octahedral to tetrahedral sites) in the particles of smaller size unit cells. From lattice parameter calculations on different particles it is determined that inversion is more favorable in the particles prepared in a basic medium than in the acidic medium due to the smaller cell size in the former.

Atif, M.; Hasanain, S. K.; Nadeem, M.

2006-05-01

24

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

25

Preparation of magnetic photocatalyst nanoparticles—TiO{sub 2}/SiO{sub 2}/Mn–Zn ferrite—and its photocatalytic activity influenced by silica interlayer  

SciTech Connect

Highlights: ? TiO{sub 2}/SiO{sub 2}/Mn–Zn ferrite acts as magnetic photocatalyst nanoparticle. ? SiO{sub 2} interlayer is used to prevent electron migration between photocatalyst and magnetic core. ? TiO{sub 2}/Mn–Zn ferrite without SiO{sub 2} interlayer shows poor magnetic and photocatalytic property. -- Abstract: A magnetic photocatalyst, TiO{sub 2}/SiO{sub 2}/Mn–Zn ferrite, was prepared by stepwise synthesis involving the co-precipitation of Mn–Zn ferrite as a magnetic core, followed by a coating of silica as the interlayer, and titania as the top layer. The particle size and distribution of magnetic nanoparticles were found to depend on the addition rate of reagent and dispersing rate of reaction. The X-ray diffractometer and transmission electron microscope were used to examine the crystal structures and the morphologies of the prepared composites. Vibrating sample magnetometer was also used to reveal their superparamagnetic property. The UV–Vis spectrophotometer was employed to monitor the decomposition of methylene blue in the photocatalytic efficient study. It was found that at least a minimum thickness of the silica interlayer around 20 nm was necessary for the inhibition of electron transference initiated by TiO{sub 2} and Mn–Zn ferrite.

Laohhasurayotin, Kritapas, E-mail: kritapas@nanotec.or.th [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Patumthani 12120 (Thailand)] [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Patumthani 12120 (Thailand); Pookboonmee, Sudarat; Viboonratanasri, Duangkamon; Kangwansupamonkon, Wiyong [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Patumthani 12120 (Thailand)] [National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Patumthani 12120 (Thailand)

2012-06-15

26

Low temperature chemical synthesis of ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Ferrite nanoparticles of Ni0.4Zn0.6-xMnxFe2O4 where x varies from 0 to 0.25 in steps of 0.05 using metal nitrates were prepared by low temperature sol-gel autocombustion method in citric acid matrix. XRD patterns of all the samples exhibit spinel crystal structures and the crystallite sizes estimated using Scherrer equation have been found to be about 30 nm. TEM measurements on these nanoparticles showed the particle sizes to be around 32 nm which are in conformity with the crystallite sizes obtained through XRD. The magnetic measurements carried out using VSM on these NiZn ferrite nanoparticles showed good magnetic performance with Mn substitutions. Deviations, if any, in magnetic properties are attributed to the increased degree of inversion in cationic distributions and also to the spin disorder at the surfaces which contributes to decreased magnetic strength of the cations present in different lattice sites.

Ramesh, S.; Rao, S. N. R.; Rao, B. Parvatheeswara; Subba Rao, P. S. V.

2012-07-01

27

Synthesis, characterisation, and applications of Mn-Zn ferrite nanoparticles  

Microsoft Academic Search

This paper deals with the synthesis, characterization, and some applications of Mn-Zn ferrite nanoparticles. The Mn-Zn ferrite was prepared from metallic nitrates, iron citrate and citric acid with the co-precipitation method with different pH values and it was further used to synthesis Mn-Zn ferrite with polariser i.e. H2O2 (Hydrogen peroxide). The X-ray diffraction pattern shows the single phase spinel structure

Madan Lal; D. K. Sharma; M. Singh

2006-01-01

28

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

29

Co–Zn ferrite nanoparticles for ferrofluid preparation: Study on magnetic properties  

Microsoft Academic Search

Co–Zn substituted nanoferrites having stoichiometric composition Co1?xZnxFe2O4 with x ranging from 0.1 to 0.5 were prepared by chemical coprecipitation method. The precipitated particles were used for the preparation of ferrofluid. Ferrofluids having Co0.5Zn0.5Fe2O4 particles could be used for the energy conversion application utilizing the magnetically induced convection for thermal dissipation. The final estimated cation contents, agreed with the initial degree

R. Arulmurugan; G. Vaidyanathan; S. Sendhilnathan; B. Jeyadevan

2005-01-01

30

Effect of zinc substitution on Co–Zn and Mn–Zn ferrite nanoparticles prepared by co-precipitation  

Microsoft Academic Search

Co(1?x)ZnxFe2O4 and Mn(1?x)ZnxFe2O4 (x=0.1–0.5) nanoparticles less than 12nm are prepared by chemical co-precipitation method which could be used for ferrofluid preparation. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Vibrational sample magnetometer (VSM) and Thermo gravimetric analysis (TGA) are utilized in order to study the effect of variation in the Zn substitution and its impact on particle size, magnetic properties like

R. Arulmurugan; B. Jeyadevan; G. Vaidyanathan; S. Sendhilnathan

2005-01-01

31

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

32

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

33

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

34

Magnetocaloric effect (MCE) in Nickel Ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

We report on the magneto caloric effect (MCE) in a Nickel ferrite (NiFe2O4) nanoparticle system. The nanoparticles were synthesized using chemical co-precipitation. Extensive characterization of structural and magnetic properties was done using XRD, TEM, DC and AC magnetization, and transverse susceptibility. The change in entropy was calculated using the thermodynamic Maxwell relation from the family of M-H curves taken at different temperatures. Maximum entropy change in nanoparticle systems is influenced by particle size, anisotropy, and collective dipolar behavior. While the MCE is not as large as that reported in bulk systems, there are advantages as ferrite nanoparticles are easily produced and the operational temperature is tuned by the average particle size. In our studies, we observed a sharp peak in M-T curves at around 60K in addition to the blocking transition which occurs at 120 K. This results in a larger entropy change in comparison with the MCE results on other reported ferrite nanoparticles. The origin of this anomalous MCE is analyzed in the context of surface anisotropy and other possible contributions in the NiFe2O4 system. Work supported by NSF through grant CTS-0408933.

Gass, J.; Morales, M. B.; Frey, N. A.; Miner, M. J.; Srinath, S.; Srikanth, H.

2007-03-01

35

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

E-print Network

Experimental observations and nucleation and growth theory of polyhedral magnetic ferrite the morphologies of ferrite nanoparticles synthesized using a radio frequency plasma torch. These nanoparticles. Keywords: Ferrite nanoparticles; High-resolution TEM; Polyhedral morphologies; Faceting; Critical nucleus

McHenry, Michael E.

36

Synthesis, characterisation, and applications of Mn-Zn ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

This paper deals with the synthesis, characterization, and some applications of Mn-Zn ferrite nanoparticles. The Mn-Zn ferrite was prepared from metallic nitrates, iron citrate and citric acid with the co-precipitation method with different pH values and it was further used to synthesis Mn-Zn ferrite with polariser i.e. H IIO II (Hydrogen peroxide). The X-ray diffraction pattern shows the single phase spinel structure of the ferrites. The effect of pH and the oxidizing agent on the electrical properties of Mn-Zn ferrite was studied. The d.c. resistivity is improved with the pH value and further improved by the addition of H IIO II (Hydrogen peroxide), which acts as a strong oxidizing agent. The dielectric constant decreases with increasing pH value; at the same time the dielectric loss also decreases. Further the decrease in dielectric properties by addition of oxidizing agent are justified by inverse proportionality between resistivity and dielectric constant.

Lal, Madan; Sharma, D. K.; Singh, M.

2006-03-01

37

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

38

Non-stoichiometric zinc-ferrite spinel nanoparticles  

Microsoft Academic Search

When prepared as a bulk material, ZnFe2O4 has a normal spinel structure with Zn2+ incorporated almost exclusively at the tetrahedral lattice sites and Fe3+ at the octahedral sites ((Zn)[Fe2]O4). Due to its “rigid” structure, its composition is also closely defined at Zn2+\\/Fe3+ ? 0.5. However, when prepared as nanoparticles, a significant proportion of Zn can enter the zinc-ferrite structure at the\\u000a octahedral

D. Makovec; M. Drofenik

2008-01-01

39

Microwave assisted low temperature synthesis of MnZn ferrite nanoparticles  

Microsoft Academic Search

MnZnFe2O4 ferrite nanoparticles were prepared by co-precipitation method using a microwave heating system at temperature of 100 °C.\\u000a X-ray diffraction reveals the samples as prepared are pure ferrite nanocrystalline phase, transmission electron microscopy\\u000a image analysis shows particles are in agglomeration state with an average size of about 10 nm, furthermore, crystal size of\\u000a samples are increased with longer microwave heating.

Lai Zhenyu; Xu Guangliang; Zheng Yalin

2007-01-01

40

The structure of compositionally constrained zinc-ferrite spinel nanoparticles  

Microsoft Academic Search

ZnFe2O4 bulk material shows a normal-spinel structure and a closely defined composition at Zn2+\\/Fe3+ ? 0.5. However, the composition of zinc ferrite, prepared as nanoparticles, can be varied in a broad range without losing\\u000a the single-phase spinel structure. In this article, structural mechanisms enabling this non-stoichiometry were studied using\\u000a the X-ray absorption fine structure (EXAFS) in combination with X-ray diffractometry (XRD), transmission

Darko Makovec; Alojz Kodre; Iztok Ar?on; Miha Drofenik

2011-01-01

41

Magnetic properties of mixed cobalt–zinc ferrite nanoparticles  

Microsoft Academic Search

Solid solutions of nonstoichiometric mixed cobalt–zinc ferrite nanoparticles Co0.73yZn0.73(1?y)Fe2.18□0.09O4, were prepared in order to study their magnetic properties as a function of cobalt content y. The saturation magnetization changes with increasing y due to the various occupancies of cations in tetrahedral and octahedral sites and\\/or to an increase in the disorder of the ferrimagnetic structure. The cobalt content and particle

J. F. Hochepied; M. P. Pileni

2000-01-01

42

Magnetic properties of mixed cobalt-zinc ferrite nanoparticles  

Microsoft Academic Search

Solid solutions of nonstoichiometric mixed cobalt-zinc ferrite nanoparticles Co0.73yZn0.73(1-y)Fe2.18□0.09O4, were prepared in order to study their magnetic properties as a function of cobalt content y. The saturation magnetization changes with increasing y due to the various occupancies of cations in tetrahedral and octahedral sites and\\/or to an increase in the disorder of the ferrimagnetic structure. The cobalt content and particle

J. F. Hochepied; M. P. Pileni

2000-01-01

43

Ferromagnetic resonance of nonstoichiometric zinc ferrite and cobalt-doped zinc ferrite nanoparticles  

Microsoft Academic Search

Ferromagnetic resonance spectra of zinc ferrite and cobalt doped zinc ferrite nanoparticles, measured at various temperatures, exhibit an invariant point at a given field. This makes it possible to determine the equation relating the resonance field shift to the peak-to-peak linewidth. When particles are frozen in a matrix in a magnetic field, the anisotropy constant of the material can be

J. F. Hochepied; M. P. Pileni

2001-01-01

44

The effect of thermal treatment on the magnetic properties of spinel ferrite nanoparticles in magnetic fluids  

NASA Astrophysics Data System (ADS)

Magnetic properties of ferrites are dependent on the crystalline structure and location of metal ions in the material. The most commonly used materials of nanoparticles in magnetic fluids are chemical stable spinel (2-3) ferrites. The preparation of ferrite nanoparticles for magnetic fluids synthesis needs a special technology. More commonly used is the wet chemical coprecipitation production technology of magnetic nanoparticles for MF. The ferrites synthesized by the wet chemical method have different magnetic characteristics if compared to the ferrites prepared by standard ceramic methods. In this paper, the physical properties of ultrafine complex spinel-type Fe _{2}Co _{0.3}Zn _{0.6}Ca _{0.1}O_{4}, Fe _{1.9}Cd _{0.1}Mn _{0.54}Zn _{0.46}O_{4}, Fe _{2}CoO_{4} and Fe _{2}Zn _{0.6}Mn _{0.3}Ca _{0.1}O_{4} ferrite particles and MF on its base, after their special thermal treatment, are studied. Tables 1, Figs 6, Refs 8.

Kronkalns, G.; Dreimane, A.; Maiorov, M. M.

2008-03-01

45

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

46

Tuning Magnetic Properties of Magnetic Recording Media Cobalt Ferrite NanoParticles by CoPrecipitation Method  

Microsoft Academic Search

Magnetic nano-particles of cobalt ferrite were prepared using co-precipitation method. X-ray diffraction, transmission electron microscope and Raman analysis have confirmed that the formation of cobalt ferrite nano-particles with different particle size depending on the rate of reaction and nucleation. X-ray photoelectron spectrometer analysis indicates that the reaction rate have little influence on the cation distribution in the tetrahedral and octahedral

Shu Chang; Qiao Haoxue

2009-01-01

47

A.C. and D.C. conductivity of NiZn ferrite nanoparticles in wet and dry conditions  

Microsoft Academic Search

Promising future applications of ferrite nanoparticles in medicine, drug delivery, sensors and ferrofluids are expected to be in wet or humid environments. Therefore nanostructured powders of ferrites having the chemical compositions.NixZn (1?x)Fe2O4 with (x=0.0, 0.25, 0.5, 0.75, and 1) were pressed immediately after preparation – by the co-precipitation method – without any drying to simulate a humid environment. The nanoparticles

S. A. Saafan; T. M. Meaz; E. H. El-Ghazzawy; M. K. El Nimr; M. M. Ayad; M. Bakr

2010-01-01

48

Precipitation of zinc ferrite nanoparticles in the Fe 2O 3–ZnO–SiO 2 glass system  

Microsoft Academic Search

Glass materials in the ZnO–Fe2O3–SiO2 system, containing zinc ferrite nanoparticles, were prepared by the sol–gel method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Mössbauer spectroscopy, AC- and DC-magnetization techniques. The gel samples, dried at 130°C, were further heat treated in air at 500 and 800°C. At 500°C zinc ferrite and hematite nanoparticles, with an average size of

M. G. Ferreira da Silva; L. C. J. Pereira; J. C. Waerenborgh

2007-01-01

49

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

Microsoft Academic Search

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.

Ecaterina Foca-Nici; Gabriela Capraru; Dorina Creanga

2010-01-01

50

Study of magnetic and structural properties of ferrofluids based on cobalt-zinc ferrite nanoparticles  

Microsoft Academic Search

Ferrofluids are colloidal systems composed of a single domain of magnetic nanoparticles with a mean diameter around 30 nm, dispersed in a liquid carrier. Magnetic Co(1-x)ZnxFe2O4 (x=0.25, 0.50, 0.75) ferrite nanoparticles were prepared via co-precipitation method from aqueous salt solutions in an alkaline medium. The composition and structure of the samples were characterized through Energy Dispersive X-ray Spectroscopy and X-ray

J. López; L. F. González-Bahamón; J. Prado; J. C. Caicedo; G. Zambrano; M. E. Gómez; J. Esteve; P. Prieto

2012-01-01

51

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

52

An Approach for Enhancement of Saturation Magnetization in Cobalt Ferrite Nanoparticles by Incorporation of Terbium Cation  

NASA Astrophysics Data System (ADS)

Cobalt ferrite nanoparticles were synthesized by a reverse micelle process. The optimum processing conditions required to fabricate nanocrystalline cobalt ferrite using a reverse micelle technique, especially the effect of water-to-surfactant molar ratios including w = 8, 10, 12, and 14, pH values in the range of 8 to 11, and annealing temperatures in the range of 400°C to 800°C, were evaluated. x-Ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), vibrating-sample magnetometry, and superconducting quantum interference device analysis were employed to evaluate the structural and magnetic properties of synthesized nanoparticles. XRD analysis confirms that the nanoparticles have a single-phase cubic spinel structure. The average particle size increases with increasing pH value and annealing temperature. Magnetization study reveals that the cobalt ferrite nanoparticles exhibit a superparamagnetic trend. The zero-field-cooled magnetization curves of cobalt ferrite nanoparticles indicated that, with an increase in pH value, the blocking temperature increases. Based on the obtained optimum parameters, terbium-substituted cobalt ferrite nanoparticles with composition CoFe2- x Tb x O4 ( x = 0.1 to 0.5) were prepared by a reverse micelle process. XRD and field-emission scanning electron microscopy evaluation demonstrated that single-phase spinel ferrites with narrow size distribution were obtained. Mössbauer spectroscopy was used to determine the site preference of terbium cation. The results confirm that terbium cations were distributed at tetrahedral and octahedral sites, but with a preference for the former. It was observed that, with an increase in terbium content, the saturation magnetization increases.

Sodaee, Tahmineh; Ghasemi, Ali; Paimozd, Ebrahim; Paesano, Andrea; Morisako, Akimitsu

2013-09-01

53

Effect of nanoparticles on the magnetic properties of Mn-Zn soft ferrite  

NASA Astrophysics Data System (ADS)

In this paper, the effect of nanostructures on the magnetic properties like the specific saturation magnetization ( ?S) and the coercivity ( HC) for Mn 0.4Zn 0.6Fe 2O 4 ferrite prepared by the co-precipitation method has been presented. We have shown by means of X-ray diffraction that the resulting ferrite is made up of nanoparticles, and that the average size of these nanoparticles calculated with the Scherrer formula depends upon the sintering temperature. When the sintering temperature is increased from 500 to 900 °C, the average nanoparticle diameter varies from 19.3 to 36.4 nm. The nanoparticle phase is further confirmed by scanning electron microscopy (SEM). Both results are found to be in good agreement. The magnetic properties are explained on the basis of the single-domain and multi-domain theory.

Mathur, Preeti; Thakur, Atul; Singh, M.

54

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

55

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

56

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

57

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

58

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

59

Induced size effect on Ni doped Nickel Zinc Ferrite Nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel zinc ferrite (NixZn1-xFe2O4 where x = 0.1, 0.3, 0.5) nanoparticles were synthesized by chemical co-precipitation method. The doping effect of nickel ions on crystalline phase, size, particle size, and saturation magnetization (M S) are investigated. The XRD patterns confirm the single crystalline phase of the nanoparticles. The lattice parameter decreases with increase in Ni content and reduces lattice strain. HRTEM images reveal the crystalline nature of nanoparticles with size distribution in 10-30 nm range. The M-H curve exhibit the superparamagnetic nature of x = 0.1 and x = 0.3 samples and ferromagnetic nature for x = 0.5 sample. Ms increases with rise in Ni2+ ions concentration. These ferrite nanoparticles are suitable for ferrofluids applications.

Kumar, Ashok; Annveer; Arora, Manju; Yadav, M. S.; Panta, R. P.

60

High-frequency magnetic properties of Ni-Zn ferrite nanoparticles synthesized by a low temperature chemical method  

Microsoft Academic Search

Spinel-structured Ni-Zn ferrite nanoparticles (NPs) have been directly synthesized by a low temperature co-precipitation method. The structure and high-frequency magnetic properties of the particles were investigated. The as-prepared Ni-Zn ferrite NPs demonstrate typical soft magnetic properties. The saturation magnetization (Ms), as high as about 60emu\\/g, was achieved. The imaginary part ?'' of the permeability shows a broad peak in the

Xuegang Lu; Gongying Liang; Qianjin Sun; Caihua Yang

2011-01-01

61

A.C. and D.C. conductivity of NiZn ferrite nanoparticles in wet and dry conditions  

Microsoft Academic Search

Promising future applications of ferrite nanoparticles in medicine, drug delivery, sensors and ferrofluids are expected to be in wet or humid environments. Therefore nanostructured powders of ferrites having the chemical compositions. NixZn (1-x)Fe2O4 with (x=0.0, 0.25, 0.5, 0.75, and 1) were pressed immediately after preparation - by the co-precipitation method - without any drying to simulate a humid environment. The

S. A. Saafan; T. M. Meaz; E. H. El-Ghazzawy; M. K. El Nimr; M. M. Ayad; M. Bakr

2010-01-01

62

Induced size effect on Ni doped Nickel Zinc Ferrite Nanoparticles  

Microsoft Academic Search

Nickel zinc ferrite (NixZn1?xFe2O4 where x=0.1, 0.3, 0.5) nanoparticles were synthesized by chemical co-precipitation method. The doping effect of nickel ions on crystalline phase, size, particle size, and saturation magnetization (M S) are investigated. The XRD patterns confirm the single crystalline phase of the nanoparticles. The lattice parameter decreases with increase in Ni content and reduces lattice strain. HRTEM images

Ashok Kumar; Annveer; Manju Arora; M. S. Yadav; R. P. Panta

2010-01-01

63

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

64

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 to occupy tetrahedral sites, contrary to what occurs in bulk ferrites. The nanopowders display a semi constant is significantly higher for these nanoparticles than for bulk ferrites. Co1.8Fe1.2O4 hal-01053683

Paris-Sud XI, Université de

65

Finite size and surface effects on the magnetic properties of cobalt ferrite nanoparticles  

Microsoft Academic Search

Cobalt ferrite, CoFe2O4, nanoparticles in the size range 2–15 nm have been prepared using a non-aqueous solvothermal method. The magnetic studies\\u000a indicate a superparamagnetic behavior, showing an increase in the blocking temperatures (ranging from 215 to more than 340 K)\\u000a with the particle size, D\\u000a TEM. Fitting M versus H isotherms to the saturation approach law, the anisotropy constant, K, and the

C. Vázquez-Vázquez; M. A. López-Quintela; M. C. Buján-Núñez; J. Rivas

2011-01-01

66

Mössbauer, X-ray diffraction and AC susceptibility studies on nanoparticles of zinc substituted magnesium ferrite  

Microsoft Academic Search

Nanoparticles of zinc substituted Mg-ferrite with compositions Mg (1- x)Zn xFe 2O 4 ( x = 0.15, 0.30 and 0.50) having particle sizes in the range 6.4 nm to 21.4 nm prepared by the co-precipitation method were characterized by 57Fe Mössbauer spectroscopy, X-ray diffratometry and AC magnetic susceptibility measurements. Mössbauer measurements at room temperature and down to 20 K clearly

B. K. Nath; P. K. Chakrabarti; S. Das; Uday Kumar; P. K. Mukhopadhyay; D. Das

2004-01-01

67

Effect of heat treatment on microwave absorption properties of Ni-Zn-Mg-La ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Spinel structure Ni-Zn-Mg-La ferrites have been prepared by the sol-gel route and investigated as a radar absorbing material (RAM) in a frequency range of 1-18 GHz. The structure and morphological studies on the nanoparticles of the ferrites have been carried out using X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The complex permeability and complex permittivity are measured by a network analyzer. The electromagnetic wave loss and microwave absorbing property are studied as a function of frequency, annealing temperature and thickness of the absorber. The results indicate that electromagnetic wave loss of the ferrite only annealed at 850 °C shows two peaks. The reflection loss varies with the change of the annealing temperature. The absorber annealed at 850 °C exhibits the best microwave absorbing properties, which is suitable for microwave absorption materials.

Liu, Yi; Wei, Shicheng; Xu, Binshi; Wang, Yujiang; Tian, Haoliang; Tong, Hui

2014-01-01

68

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

69

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

70

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

71

Development of synthesis method for spinel ferrite magnetic nanoparticle and its superparamagnetic properties.  

E-print Network

??The magnetic spinel ferrite nanoparticle is exceptionally intriguing nanocrystal system due to the industrial importance of various technical applications and the scientific significance of studying… (more)

Han, Man Huon

2008-01-01

72

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

Microsoft Academic Search

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

Andrea Kraus; Kunawoot Jainae; Fuangfa Unob; Nipaka Sukpirom

2009-01-01

73

Comparison effects and electron spin resonance studies of ?-Fe2O4 spinel type ferrite nanoparticles.  

PubMed

?-Fe2O4 spinel type ferrite nanoparticles have been synthesized by cetyltrimethylammonium bromide (CTAB) and ethylenediaminetetraacetic acid (EDTA) assisted hydrothermal route by using NaOH solution. Electron spin resonance (ESR/EPR) measurements of ?-Fe2O4 nanoparticles have been performed by a conventional x-band spectrometer at room temperature. The comparison effect of nanoparticles prepared by using CTAB and EDTA in different ?-doping on the structural and morphological properties have been investigated in detail. The effect of EDTA-assisted synthesis for ?-Fe2O4 nanoparticles are refined, and thus the spectroscopic g-factor are detected by using ESR signals. These samples can be considered as great benefits for magnetic recording media, electromagnetic and drug delivery applications. PMID:24858357

Bayrakdar, H; Yalç?n, O; Cengiz, U; Özüm, S; Anigi, E; Topel, O

2014-11-11

74

Comparison effects and electron spin resonance studies of ?-Fe2O4 spinel type ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

?-Fe2O4 spinel type ferrite nanoparticles have been synthesized by cetyltrimethylammonium bromide (CTAB) and ethylenediaminetetraacetic acid (EDTA) assisted hydrothermal route by using NaOH solution. Electron spin resonance (ESR/EPR) measurements of ?-Fe2O4 nanoparticles have been performed by a conventional x-band spectrometer at room temperature. The comparison effect of nanoparticles prepared by using CTAB and EDTA in different ?-doping on the structural and morphological properties have been investigated in detail. The effect of EDTA-assisted synthesis for ?-Fe2O4 nanoparticles are refined, and thus the spectroscopic g-factor are detected by using ESR signals. These samples can be considered as great benefits for magnetic recording media, electromagnetic and drug delivery applications.

Bayrakdar, H.; Yalç?n, O.; Cengiz, U.; Özüm, S.; Anigi, E.; Topel, O.

2014-11-01

75

Synthesis and characterization of Ni–Zn ferrite nanoparticles  

Microsoft Academic Search

Nickel zinc ferrite nanoparticles NixZn1?xFe2O4 (x=0.1, 0.3, 0.5) have been synthesized by a chemical co-precipitation method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, electron paramagnetic resonance, dc magnetization and ac susceptibility measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline NixZn1?xFe2O4 nanoparticles. The lattice parameter decreases with increase in Ni content resulting in a

G. S. Shahane; Ashok Kumar; Manju Arora; R. P. Pant; Krishan Lal

2010-01-01

76

Mn–ferrite nanoparticles via reverse microemulsions: synthesis and characterization  

Microsoft Academic Search

Mn–ferrite nanoparticles were synthesized by thermal treatment at 800 °C of manganese and iron oxo-hydroxides obtained via\\u000a water-in-oil microemulsions consisting of n-hexanol as continuous phase, cetyl trimethyl ammonium bromide (CTAB) as the cationic surfactant and aqueous solutions of\\u000a metal salts and precipitant agent (tetramethyl ammonium hydroxide) as reagents. Nanoparticles were synthesized using a multi-microemulsion\\u000a approach. Two different co-precipitation routes are described

Alessandra Scano; Guido Ennas; Francesca Frongia; Aurelio La Barbera; M. Arturo López-Quintela; Giaime Marongiu; Giorgio Paschina; Davide Peddis; Martina Pilloni; Carlos Vázquez-Vázquez

2011-01-01

77

Structural And Magnetic Properties Of Ni-Zn Ferrite Nanoparticles  

Microsoft Academic Search

Nickel zinc ferrite nanoparticles of the composition NixZn1-xFe2O4 (x = 0.1, 0.3, 0.5) have been synthesized by the chemical co-precipitation method. The samples were characterized by X-ray diffraction, TEM, EPR, DC magnetization and AC susceptibility measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline phase of NixZn1-xFe2O4 (x = 0.1, 0.3, 0.5) nanoparticles. Lattice parameter decreases with the

G. S. Shahane; Ashok Kumar; R. P. Pant; Krishan Lal

2010-01-01

78

The Effect of Alkali Concentration on the Structural and Magnetic Properties of Mn-Ferrite Nanoparticles Prepared via the Coprecipitation Method  

NASA Astrophysics Data System (ADS)

MnFe2O4 nanoparticles were synthesized using the coprecipitation method under two different NaOH concentration settings as reaction agents at 355 K (82 °C). Structural and morphological properties of the nanoparticles were examined using X-ray diffraction and a scanning electron microscope. The decrease of NaOH concentration led to the increase of particle size. This result contradicts two recently published reports. Also, the decrease of NaOH concentration led to more crystallinity and a narrower particle size distribution. The results were evaluated from a chemical point of view and were based on the supersaturation level, which was influenced by alkali concentration. It was concluded that the higher NaOH concentration led to a more rapid nucleation and more random cation distribution. The magnetic properties of the nanoparticles examined by permeameter and faraday-balance equipment were consistent with the structural and morphological properties of the particles.

Pourbafarani, Somayeh

2014-09-01

79

Dielectric properties of Mn0.5Zn0.5Fe2O4 ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Mn0.5Zn0.5Fe2O4 ferrite nanoparticles have been prepared by sol-gel auto-combustion method with a view to understand the role of oxidizer to fuel ratio (OFR) on the dielectric properties. XRD study shows the formation of cubic ferrite with spinel structure and particle size increases with the increase in concentration of fuel. Dielectric properties and AC conductivity of the sample measured at room temperature are reported. OFR plays a vital role in determining the dielectric properties and AC conductivity of the prepared samples.

Murugesan, C.; Md Gazzali, P. M.; Sathyamoorthy, B.; Chandrasekaran, G.

2013-02-01

80

Microstructural Evolution Model of the Sintering Behavior and Magnetic Properties of NiZn Ferrite Nanoparticles  

E-print Network

Microstructural Evolution Model of the Sintering Behavior and Magnetic Properties of NiZn Ferrite jlwoods@andrew.cmu.edu, c SCalvin@slc.edu, d jhuth@Spang.co, e mm7g@andrew.cmu.edu Keywords: Ferrite, nanoparticle, sintering, microstructure. Abstract. The sintering of RF plasma synthesized NiZn ferrite

McHenry, Michael E.

81

Study of magnetic and structural properties of ferrofluids based on cobalt-zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Ferrofluids are colloidal systems composed of a single domain of magnetic nanoparticles with a mean diameter around 30 nm, dispersed in a liquid carrier. Magnetic Co(1-x)ZnxFe2O4 (x=0.25, 0.50, 0.75) ferrite nanoparticles were prepared via co-precipitation method from aqueous salt solutions in an alkaline medium. The composition and structure of the samples were characterized through Energy Dispersive X-ray Spectroscopy and X-ray diffraction, respectively. Transmission Electron Microscopy (TEM) studies permitted determining nanoparticle size; grain size of nanoparticle conglomerates was established via Atomic Force Microscopy. The magnetic behavior of ferrofluids was characterized by Vibrating Sample Magnetometer (VSM); and finally, a magnetic force microscope was used to visualize the magnetic domains of Co(1-x)ZnxFe2O4 nanoparticles. X-ray diffraction patterns of Co(1-x)ZnxFe2O4 show the presence of the most intense peak corresponding to the (311) crystallographic orientation of the spinel phase of CoFe2O4. Fourier Transform Infrared Spectroscopy confirmed the presence of the bonds associated to the spinel structures; particularly for ferrites. The mean size of the crystallite of nanoparticles determined from the full-width at half maximum of the strongest reflection of the (311) peak by using the Scherrer approximation diminished from (9.5±0.3) nm to (5.4±0.2) nm when the Zn concentration increases from 0.21 to 0.75. The size of the Co-Zn ferrite nanoparticles obtained by TEM is in good agreement with the crystallite size calculated from X-ray diffraction patterns, using Scherer's formula. The magnetic properties investigated with the aid of a VSM at room temperature presented super-paramagnetic behavior, determined by the shape of the hysteresis loop. In this study, we established that the coercive field of Co(1-x)ZnxFe2O4 magnetic nanoparticles, the crystal and nanoparticle sizes determined by X-ray Diffraction and TEM, respectively, decrease with the increase of the Zn at%. Finally, our magnetic nanoparticles are not very hard magnetic materials given that the hysteresis loop is small and for this reason Co(1-x)ZnxFe2O4 nanoparticles are considered as soft magnetic material.

López, J.; González-Bahamón, L. F.; Prado, J.; Caicedo, J. C.; Zambrano, G.; Gómez, M. E.; Esteve, J.; Prieto, P.

2012-02-01

82

Magnetic and structural properties of ferrofluids based on Cobalt-Zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Ferrofluids are colloidal systems composed of a single domain of magnetic nanoparticles with a mean diameter around 10 nm, dispersed in a liquid carrier. Magnetic Co(1-x)ZnxFe2O4 ferrite nanoparticles were prepared via co-precipitation method from aqueous salt solutions in an alkaline medium. The composition and structure of the samples were characterized through EDX and XRD, respectively. Transmission Electron Microscopy studies permitted determining nanoparticle size. Grain size of nanoparticle conglomerates was established via Atomic Force Microscopy. The magnetic behavior of ferrofluids was characterized by Vibrating Sample Magnetometer; and finally, a Magnetic Force Microscope was used to visualize the magnetic domains of nanoparticles. The mean size of the crystallite of nanoparticles determined by using the Scherrer approximation diminished when the Zn concentration increases. The size of the nanoparticles obtained by TEM is in good agreement with the crystallite size calculated from XRD measures. The magnetic properties investigated at room temperature presented super-paramagnetic behavior, determined by the shape of the hysteresis loop. Finally, our magnetic nanoparticles are considered a soft magnetic material.

Prieto, P.; Lopez, J.; Gomez, M. E.; Prado, J.; Caicedo, J.; Zambrano, G.; Gonzalez, L.; Esteve, J.

2012-02-01

83

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

84

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

85

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

86

Influence of Zn–Zr ions on physical and magnetic properties of co-precipitated cobalt ferrite nanoparticles  

Microsoft Academic Search

Cobalt ferrite nanoparticles having the chemical formula CoFe2?2xZrxZnxO4 with x ranging from 0.0 to 0.4 were prepared by chemical co-precipitation method. The powder X-ray diffraction pattern confirms the spinel structure for the prepared compound. The particle size was calculated from the most intense peak (311) using Scherrer formula. The particle size of the samples was found within the range of

I. H. Gul; A. Maqsood

2007-01-01

87

Influence of Zn Zr ions on physical and magnetic properties of co-precipitated cobalt ferrite nanoparticles  

Microsoft Academic Search

Cobalt ferrite nanoparticles having the chemical formula CoFe2-2xZrxZnxO4 with x ranging from 0.0 to 0.4 were prepared by chemical co-precipitation method. The powder X-ray diffraction pattern confirms the spinel structure for the prepared compound. The particle size was calculated from the most intense peak (3 1 1) using Scherrer formula. The particle size of the samples was found within the

I. H. Gul; A. Maqsood

2007-01-01

88

Synthesis of metal ferrite (MFe2O4, M?=?Co, Cu, Mg, Ni, Zn) nanoparticles as humidity sensor materials  

Microsoft Academic Search

Humidity sensitivity of metal ferrite nanoparticles [MFe2O4, M (II)?=?Co, Cu, Mg, Ni and Zn] prepared by solid-state reaction of inorganic precursors was studied. The process was convenient, environmentally-friendly, inexpensive and efficient. The spinel structure of the compounds prepared by this method was confirmed by XRD and FT-IR studies. The surface morphology was observed by scanning electron microscopy, and the surface

V. Jeseentharani; Mary George; B. Jeyaraj; A. Dayalan; K. S. Nagaraja

2012-01-01

89

Chemisorption of cyanogen chloride by spinel ferrite magnetic nanoparticles.  

PubMed

Spinel ferrite magnetic nanoparticles, MnFe2O4, NiFe2O4, and CoFe2O4, were synthesized and used as gas-phase adsorbents for the removal of cyanogen chloride from dry air. Fixed-bed adsorption breakthrough experiments show adsorption wave behavior at the leading edge of the breakthrough curve that is not typical of physically adsorbed species. Fourier transform infrared spectroscopy (FTIR) results indicate that CK is reacting with the spinel ferrite surface and forming a carbamate species. The reaction is shown to be a function of the hydroxyl groups and adsorbed water on the surface of the particles as well as the metallic composition of the particles. The surface reaction decreases the remnant and saturation magnetism of the MnFe2O4 and CoFe2O4 particles by approximately 25%. PMID:23540752

Glover, T Grant; DeCoste, Jared B; Sabo, Daniel; Zhang, Z John

2013-05-01

90

Mössbauer, X-ray diffraction and AC susceptibility studies on nanoparticles of zinc substituted magnesium ferrite  

NASA Astrophysics Data System (ADS)

Nanoparticles of zinc substituted Mg-ferrite with compositions Mg(1- x)Zn x Fe2O4 ( x = 0.15, 0.30 and 0.50) having particle sizes in the range 6.4 nm to 21.4 nm prepared by the co-precipitation method were characterized by 57Fe Mössbauer spectroscopy, X-ray diffratometry and AC magnetic susceptibility measurements. Mössbauer measurements at room temperature and down to 20 K clearly indicate presence of superparamagnetic particles in all the samples. AC magnetic susceptibility data show lowering of blocking temperature with decrease of particle size. Superparamagnetic relaxation was observed for larger particle size in samples with higher Zn content, which is attributed to the weakening of A-B exchange interaction in ferrite lattice due to replacement of Fe3 + in tetrahedral site by Zn2 + ions.

Nath, B. K.; Chakrabarti, P. K.; Das, S.; Kumar, Uday; Mukhopadhyay, P. K.; Das, D.

2004-06-01

91

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

92

Effect of samarium substitution on structural and magnetic properties of magnesium ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Samarium doped magnesium ferrite was prepared (MgSmxFe2-xO4) by sol-gel method. X-ray diffraction analysis reveals that the samples are single phasic with crystallite sizes in the 13-25 nm regime. Increase in lattice parameter with doping concentration suggests the expansion in unit cell with Sm3+ doping. Fourier Transform Infrared Spectrum shows substitution of Sm3+ ions in octahedral B site. Transmission Electron Micrograph shows the spherical shape of nano-particles. Magnetic measurement shows a decrease in magnetization with doping which is explained using dependence on particle size.

Thankachan, Smitha; Jacob, Binu P.; Xavier, Sheena; Mohammed, E. M.

2013-12-01

93

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

94

A.C. and D.C. conductivity of NiZn ferrite nanoparticles in wet and dry conditions  

NASA Astrophysics Data System (ADS)

Promising future applications of ferrite nanoparticles in medicine, drug delivery, sensors and ferrofluids are expected to be in wet or humid environments. Therefore nanostructured powders of ferrites having the chemical compositions. Ni xZn (1- x) Fe 2O 4 with ( x=0.0, 0.25, 0.5, 0.75, and 1) were pressed immediately after preparation - by the co-precipitation method - without any drying to simulate a humid environment. The nanoparticles were characterized by X-ray diffraction analysis (XRD) to be sure of the formation of the ferrite in nanoscale. The infrared (IR) spectroscopy of the samples ensures the existence of water as well as the characteristic absorption bands of ferrites. The ac and dc conductivity of the samples had been investigated immediately after preparation (the as-prepared samples). Then, the samples were dried at 200 °C for about 12 h and reinvestigated. The behavior of conductivity differs significantly in the two cases showing a noticeable effect due to humidity. Also, the magnetic induction of the as-prepared samples was investigated by using the vibrating sample magnetometer (VSM). The samples show superparamagnetic behavior.

Saafan, S. A.; Meaz, T. M.; El-Ghazzawy, E. H.; El Nimr, M. K.; Ayad, M. M.; Bakr, M.

2010-08-01

95

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

96

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

97

Variation in structural and dielectric properties of co-precipitated nanoparticles strontium ferrites due to value of pH  

Microsoft Academic Search

Nanoparticles of strontium ferrites with nominal composition SrFe12O19 were prepared by co-precipitation method, by decreasing pH from 13 to 8 with a regular step of 1. The secondary phase of ?-Fe2O3 was increased with the decrease in pH. The crystallite size estimated from X-rays diffraction data was in the range 52–70nm, which is much smaller than that already reported. Most

M. Anis-ur-Rehman; G. Asghar

2011-01-01

98

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

E-print Network

Zinc ferrite nanoparticles as MRI contrast agentsw Carlos Ba´ rcena,a Amandeep K. Sra,a Girija S, a series of spinel-structured ferrites, MFe2O4 (M = Mn2+ , Fe2+ , Co2+ , Ni2+ ), were reported as novel MRI.e., Mn2+ occupies both A and B sites), whereas the other metal ferrites have an inverse spinel structure

Gao, Jinming

99

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

100

Cytotoxicity of nickel zinc ferrite nanoparticles on cancer cells of epithelial origin  

PubMed Central

In this study, in vitro cytotoxicity of nickel zinc (NiZn) ferrite nanoparticles against human colon cancer HT29, breast cancer MCF7, and liver cancer HepG2 cells was examined. The morphology, homogeneity, and elemental composition of NiZn ferrite nanoparticles were investigated by scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy, respectively. The exposure of cancer cells to NiZn ferrite nanoparticles (15.6–1,000 ?g/mL; 72 hours) has resulted in a dose-dependent inhibition of cell growth determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The quantification of caspase-3 and -9 activities and DNA fragmentation to assess the cell death pathway of the treated cells showed that both were stimulated when exposed to NiZn ferrite nanoparticles. Light microscopy examination of the cells exposed to NiZn ferrite nanoparticles demonstrated significant changes in cellular morphology. The HepG2 cells were most prone to apoptosis among the three cells lines examined, as the result of treatment with NiZn nanoparticles. In conclusion, NiZn ferrite nanoparticles are suggested to have potential cytotoxicity against cancer cells. PMID:23885175

Al-Qubaisi, Mothanna Sadiq; Rasedee, Abdullah; Flaifel, Moayad Husein; Ahmad, Sahrim HJ; Hussein-Al-Ali, Samer; Hussein, Mohd Zobir; Eid, Eltayeb EM; Zainal, Zulkarnain; Saeed, Mohd; Ilowefah, Muna; Fakurazi, Sharida; Isa, Norhaszalina Mohd; Zowalaty, Mohamed Ezzat El

2013-01-01

101

Static magnetic and microwave properties of Li-ferrite films prepared by pulsed laser deposition  

E-print Network

Static magnetic and microwave properties of Li-ferrite films prepared by pulsed laser deposition F University, Fort Collins, Colorado 80523 Highly textured Li-ferrite films have been synthesized by pulsed approaching 1000 °C the growth mode was predominantly 333 . A similar growth mode was recently reported for Ni-ferrite

Patton, Carl

102

Magnetic Study of Doped Ba Ferrites Prepared by Citrate Method  

NASA Astrophysics Data System (ADS)

The M-type barium ferrite is doped with either Co2+-Ti4+ or Co2+-Zr4+ pairs to reduce its intrinsically high uniaxial magnetic anisotropy in order to make fine particles for magnetic recording. The magnetic parameters were investigated by magnetic measurements and the Mössbauer spectroscopy. Compounds (BaF) obtained from BaCo x (Ti,Zr) x Fe12-2x O19 with 0?x?1.0 have been prepared by the modified citrate method with the initial ratio of Ba:Fe equal to 1:10.8. The substitution of Co - Ti or Co - Zr for Fe3+ ions affects mainly the positions 2a and 4f 2. Ba ferrite with the substitution x ? 0.8 is promising for perpendicular recording media applications.

Grusková, A.; Sláma, J.; Dosoudil, R.; Kevická, D.; Jan?árik, V.; Lipka, J.

2002-02-01

103

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

104

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

105

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

106

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

NASA Astrophysics Data System (ADS)

We report the influence of Al3+ doping on the microstructural and Mössbauer properties of ferrite nanoparticles of basic composition Ni0.2Cd0.3Fe2.5 - x Al x O4 (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.

Batoo, Khalid Mujasam

2011-08-01

107

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

108

Effect of Substitutions of Zn for Mn on Size and Magnetic Properties of Mn–Zn Ferrite Nanoparticles  

Microsoft Academic Search

In this study Mn–Zn ferrite nanoparticles (Mn(1?x)Zn\\u000a x\\u000a Fe2O4, x=0, 0.3 and 0.5) were produced by a chemical co-precipitation method. The structure and size of the Mn–Zn ferrite nanoparticles\\u000a were characterized using X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Results show that the ferrite\\u000a nanoparticles have the spinel structure. It was found that the size of Mn–Zn ferrite nanoparticles

A. Amirabadizadeh; H. Farsi; M. Dehghani; H. Arabi

109

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

110

Structural And Magnetic Properties Of Ni-Zn Ferrite Nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel zinc ferrite nanoparticles of the composition NixZn1-xFe2O4 (x = 0.1, 0.3, 0.5) have been synthesized by the chemical co-precipitation method. The samples were characterized by X-ray diffraction, TEM, EPR, DC magnetization and AC susceptibility measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline phase of NixZn1-xFe2O4 (x = 0.1, 0.3, 0.5) nanoparticles. Lattice parameter decreases with the increase in nickel content. The magnetic measurements shows superparamagnetic nature of the samples for x = 0.1 and 0.3 whereas for x = 0.5 the material shows ferromagnetic nature. The saturation magnetization is low and increases with increase in nickel content. The superparamagnetic nature of the samples is supported by the EPR and ac susceptibility measurement studies. The blocking temperature increases with the nickel concentration. The changes in the magnetic properties have been explained by the redistribution of the cations on A and B sites.

Shahane, G. S.; Kumar, Ashok; Pant, R. P.; Lal, Krishan

2010-10-01

111

Synthesis and characterization of Ni-Zn ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Nickel zinc ferrite nanoparticles Ni xZn 1- xFe 2O 4 ( x=0.1, 0.3, 0.5) have been synthesized by a chemical co-precipitation method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, electron paramagnetic resonance, dc magnetization and ac susceptibility measurements. The X-ray diffraction patterns confirm the synthesis of single crystalline Ni xZn 1- xFe 2O 4 nanoparticles. The lattice parameter decreases with increase in Ni content resulting in a reduction in lattice strain. Similarly crystallite size increases with the concentration of Ni. The magnetic measurements show the superparamagnetic nature of the samples for x=0.1 and 0.3 whereas for x=0.5 the material is ferromagnetic. The saturation magnetization is 23.95 emu/g and increases with increase in Ni content. The superparamagnetic nature of the samples is supported by the EPR and ac susceptibility measurement studies. The blocking temperature increases with Ni concentration. The increase in blocking temperature is explained by the redistribution of the cations on tetrahedral (A) and octahedral (B) sites.

Shahane, G. S.; Kumar, Ashok; Arora, Manju; Pant, R. P.; Lal, Krishan

2010-04-01

112

Effect of Ferritic Density and Zinc on Magnetic Properties of Cobalt Ferrite Nanocomposites  

Microsoft Academic Search

Cobalt ferrite nanocomposite was investigated for RF applications. Magnetic nanocomposites were fabricated at different ferritic densities. Cobalt zinc ferrite nanocomposite was also prepared to study the effect of zinc. The size of magnetic nanoparticle was measured by transmission electron microscopy (TEM), while its crystalline structure was characterized by X-ray diffraction (XRD). Toroidal sample was made by compact method. The density

Hai Dong; A. Meininger; Kyoung-Sik Moon; L. Martin; C. P. Wong

2006-01-01

113

Preparation and characterization of Zn substituted Li-Mg ferrites  

SciTech Connect

Studies on preparation and characterization of Zn substituted Li-Mg ferrites having the general formula Li{sub x}Mg{sub 0.4}Zn{sub 0.6-2x}Fe{sub 2+x}O{sub 4} (where x=0, 0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) have been carried out. These polycrystalline ferrites were prepared by a standard ceramic technique. The single-phase formation was confirmed from X-ray diffractograms. The lattice parameter 'a', bond lengths R{sub A}, R{sub B} and site radii r{sub A}, r{sub B} were found to increase linearly with increase in Zn content. IR absorption spectral studies show two fundamental absorption bands {nu}{sub 1} and {nu}{sub 2} in the frequency range 600-400 cm{sup -1}. The center frequency of {nu}{sub 1} and {nu}{sub 2} was found to shift towards low frequency side. The average grain diameter determined from SEM studies was found to increase with Zn content, it is maximum for Zn=0.3 and then it decreases with further increase in Zn content. The Curie temperature was found to decrease linearly with Zn content.

Shaikh, A.M.; Watawe, S.C.; Jadhav, S.A.; Chougule, B.K

2002-12-01

114

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

115

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

116

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

117

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

118

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

119

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

E-print Network

Iron-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 nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm

Volinsky, Alex A.

120

A simple model for the magnetocrystalline anisotropy in mixed ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

A simple model, based on the relative occupancy of tetrahedral and octahedral sites by different cations, is proposed for the magnetocrystalline anisotropy of mixed ferrite nanoparticles. According to this model, the total magnetocrystalline anisotropy is the weighted average of the contributions of the anisotropies of Fe3+ and M2+ ions in A and B sites. The model predictions are confirmed in the case of cobalt-zinc ferrite.

de Biasi, R. S.; Cardoso, L. H. G.

2012-09-01

121

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

122

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

123

Influence of size/crystallinity effects on the cation ordering and magnetism of ?-lithium ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

?-lithium ferrite (Li0.5Fe2.5O4) nanoparticles have been prepared using two synthesis routes: citrate gel decomposition as well as the Pechini method. Analysis of HRTEM images of the particles showed that they have a core/shell structure, an average size of ˜10 nm and stacking faults parallel to the (110) planes. In both samples, the distribution of the Li and Fe cations was found to be partially ordered on the octahedral sites (Wyckoff positions 4b and 12d of space group P4332). According to literature data, Li0.5Fe2.5O4 should adopt a disordered spinel structure (so called ?-phase, space group Fd3¯m) for crystallites of 10 nm or less in size. In this study it is shown that (a) the symmetry of the Li0.5Fe2.5O4 nanoparticles depends on the degree of their crystallinity and (b) the ordered crystal structures can be formed even for crystallites of 5-6 nm in size. By fitting the room temperature Mössbauer spectra it was obtained that the hyperfine field values are lower in the sample synthesized by the Pechini method. The Pechini process probably resulted in larger distortions of the cation environments than the citrate gel decomposition method. The saturation magnetization in turn was higher for the material obtained by the gel decomposition approach.

Jovi?, N.; Prekajski, M.; Kremenovi?, A.; Jan?ar, B.; Kahlenberg, V.; Anti?, B.

2012-02-01

124

Preparation of chitosan nanoparticles using methacrylic acid  

Microsoft Academic Search

In this work the preparation of chitosan nanoparticle was investigated using methacrylic acid in different conditions and studied by particle size analyzer, zeta-potential, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM). The particle size was dependent on the chitosan concentration used during the preparation method. Nanoparticles with sizes as small as 60 nm were

Márcia R. de Moura; Fauze A. Aouada; Luiz H. C. Mattoso

2008-01-01

125

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

126

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

127

Bulk magnetic properties of Co-Zn ferrites prepared by the co-precipitation method  

Microsoft Academic Search

The alternating current (a.c.) susceptibility versus temperature and magnetization measurements are reported for the disordered spinel ferrite system Znx Co1-x Fe2 O4 prepared by a wet chemical method before and after high temperature annealing. The low field a.c. susceptibility measurements indicate that the low temperature synthesis of wet prepared Co-Zn ferrites aids the formation of spin-clusters and thereby increases the

P. B. Pandya; H. H. Joshi; R. G. Kulkarni

1991-01-01

128

Evaluation of iron-cobalt/ferrite core-shell nanoparticles for cancer thermotherapy  

E-print Network

or thermoablative cancer therapy. Magnetic hyperthermia uses MNPs to heat cancerous regions in an rf field. MetallicEvaluation of iron-cobalt/ferrite core-shell nanoparticles for cancer thermotherapy A. H. Habiba P. Chaudhary Hillman Cancer Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA

McHenry, Michael E.

129

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

130

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

131

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

132

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

Microsoft Academic Search

Cobalt–zinc ferrite (Co0.8Zn0.2Fe2O4) was prepared by combustion method, using cobalt, zinc and iron nitrates. The crystallinity of the as-burnt powder was developed by annealing at 700°C. Crystalline phase was investigated by XRD. Using Williamson–Hall method, the average crystallite sizes for nanoparticles were determined to be about 27nm before and 37nm after annealing, and residual stresses for annealed particles were omitted.

M. H. Yousefi; S. Manouchehri; A. Arab; M. Mozaffari; Gh. R. Amiri; J. Amighian

2010-01-01

133

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

134

Magnetic and RF-electromagnetic absorbing study of aluminum doped nickel ferrites prepared by two techniques  

NASA Astrophysics Data System (ADS)

Pure phase aluminum doped nickel ferrite nanoparticles [NiAl x Fe2-x O4] with x = 0.0, 0.25 and 0.5 have been investigated for magnetic and electromagnetic absorbing properties in S band and influence of Al3+ ions has been studied. Nickel aluminum ferrites have been synthesized by co-precipitation and sol-gel auto combustion routes. Magneto-dielectric properties were measured in terms of complex permeability (?*) and complex permittivity (?*) at 300 K in the frequency range of 1 MHz to 3 GHz using RF material/impedance analyzer. Dielectric permittivity (?? and ??) has been observed to decrease with the increase in applied frequency and concentration of aluminum ions (x = 0.0-0.5). Magnetic permeability (?? and ??) has been found to decrease with the increase in aluminum ions concentration. Electromagnetic absorbing properties were studied for all the samples by calculating the reflection losses (RL) in the frequency range of 1 MHz-3 GHz using the permittivity and permeability measurements in accordance with the transmission line theory. RL (dB) values lie in the range of -42 dB to -57 dB. RL values (> -10 dB) confirm more than 90% absorption of electromagnetic waves incident normal to the material surface. Aluminum doping has increased the RL values from -45 dB to -57 dB along with the shift of RL dip towards the higher frequency side for the samples prepared by sol-gel auto combustion technique. Magnetic properties have been studied by vibrating samples magnetometer (VSM) at room temperature and a decrease in magnetic properties has been observed due to increase in x from 0.0-0.5.

Pervaiz, Erum; Gul, I. H.; Syam Virk, M.

2014-03-01

135

Synthesis and magnetic properties of CoFe2O4 spinel ferrite nanoparticles doped with lanthanide ions  

Microsoft Academic Search

Lanthanide ions have been doped into cobalt spinel ferrites using an oil-in-water micellar method to form CoLn0.12Fe1.88O4 nanoparticles with Ln=Ce, Sm, Eu, Gd, Dy, or Er. Doping with lanthanide ions (LnIII) modulates the magnetic properties of cobalt spinel ferrite nanoparticles. In particular cases of Gd3+ or Dy3+ ions, a dramatic increase in the blocking temperature and coercivity is observed. Indeed,

Myrtil L. Kahn; Z. John Zhang

2001-01-01

136

The effect of solution temperature on crystallite size and magnetic properties of Zn substituted Co ferrite nanoparticles  

Microsoft Academic Search

In this work zinc substituted cobalt ferrite nanoparticles (Co0.5Zn0.5Fe2O4) have been synthesized by the coprecipitation method, using stable ferric, zinc and cobalt salts with sodium hydroxide, at different solution temperatures, from room temperature to 363K. The cobalt–zinc ferrite crystalline phase, the particle size and the morphology of the resulting nanoparticles were studied by X-ray diffraction and transmission electron microscopy. The

M. Mozaffari; S. Manouchehri; M. H. Yousefi; J. Amighian

2010-01-01

137

Very thin barium ferrite particles prepared by a novel technique: Ion exchange resin method  

NASA Astrophysics Data System (ADS)

Very thin hexagonal barium ferrite particles have been prepared by a new method—ion exchange resin method. The exchanged resin when heated to 850 °C, transformed to the hexagonal ferrite BaFe12O19 as confirmed by x-ray diffraction. These particles show single-domain behavior with average diameter D¯=220 nm, average aspect ratio D¯/t¯=13, specific magnetization ?=71 emu/g and coercivity Hc=3800 Oe.

Zhong, Wei; Ding, Weiping; Jiang, Yumei; Wang, Liang; Zhang, Ning; Zhang, Shiyuan; Du, Youwei; Yan, Qijie

1999-04-01

138

Very thin barium ferrite particles prepared by a novel technique: Ion exchange resin method  

Microsoft Academic Search

Very thin hexagonal barium ferrite particles have been prepared by a new method-ion exchange resin method. The exchanged resin when heated to 850 °C, transformed to the hexagonal ferrite BaFe12O19 as confirmed by x-ray diffraction. These particles show single-domain behavior with average diameter D=220 nm, average aspect ratio D\\/t=13, specific magnetization sigma=71 emu\\/g and coercivity Hc=3800 Oe.

Wei Zhong; Weiping Ding; Yumei Jiang; Liang Wang; Ning Zhang; Shiyuan Zhang; Youwei Du; Qijie Yan

1999-01-01

139

Magnetic properties of bio-synthesized zinc ferrite nanoparticles  

SciTech Connect

The magnetic properties of zinc ferrite (Zn-substituted magnetite, Zn{sub y}Fe{sub 1-y}Fe{sub 2}O{sub 4}) formed by a microbial process compared favorably with chemically synthesized materials. A metal reducing bacterium, Thermoanaerobacter, strain TOR-39 was incubated with Zn{sub x}Fe{sub 1-x}OOH (x=0.01, 0.1, and 0.15) precursors and produced nanoparticulate zinc ferrites. Composition and crystalline structure of the resulting zinc ferrites were verified using X-ray fluorescence, X-ray diffraction, transmission electron microscopy, and neutron diffraction. The average composition from triplicates gave a value for y of 0.02, 0.23, and 0.30 with the greatest standard deviation of 0.02. Average crystallite sizes were determined to be 67, 49, and 25 nm, respectively. While crystallite size decreased with more Zn substitution, the lattice parameter and the unit cell volume showed a gradual increase in agreement with previous literature values. The magnetic properties were characterized using a superconducting quantum interference device magnetometer and were compared with values for the saturation magnetization (M{sub s}) reported in the literature. The averaged M{sub s} values for the triplicates with the largest amount of zinc (y=0.30) gave values of 100.1, 96.5, and 69.7 emu/g at temperatures of 5, 80, and 300 K, respectively indicating increased magnetic properties of the bacterially synthesized zinc ferrites.

Yeary, Lucas W [ORNL; Moon, Ji Won [ORNL; Rawn, Claudia J [ORNL; Love, Lonnie J [ORNL; Rondinone, Adam Justin [ORNL; Thompson, James R [ORNL; Chakoumakos, Bryan C [ORNL; Phelps, Tommy Joe [ORNL

2011-01-01

140

Influence of Zn Zr ions on physical and magnetic properties of co-precipitated cobalt ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Cobalt ferrite nanoparticles having the chemical formula CoFe 2-2xZr xZn xO 4 with x ranging from 0.0 to 0.4 were prepared by chemical co-precipitation method. The powder X-ray diffraction pattern confirms the spinel structure for the prepared compound. The particle size was calculated from the most intense peak (3 1 1) using Scherrer formula. The particle size of the samples was found within the range of 12-23 nm for all the compositions. The magnetic and electrical properties of these materials have been studied as a function of temperature. Activation energy and drift mobility have been calculated from the DC electrical resistivity measurements. Dielectric properties such as dielectric constant and dielectric loss tangent were measured at room temperature in the frequency range 100 Hz-1 MHz.

Gul, I. H.; Maqsood, A.

2007-09-01

141

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

142

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

143

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

144

A LOW TEMPERATURE PATH TO THE PREPARATION OF CoFe2O4 FERRITE  

Microsoft Academic Search

Ultrafine cobalt ferrite has been prepared by the decomposition of cobalt oxalate-hydrazinate complex, which is used as precursor. The preparation and thermal decomposition of the precursor have been studied using chemical, thermal, and infrared techniques. The precursor decomposes at low temperatures with the effusion of large amounts of gases. The coordination compounds used as chemical precursors have to include, ligands,

E. Chirtop; I. Mitova; R. M. Ion; M. Iliescu

145

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

146

Irregular distribution of metal ions in ferrites prepared by co-precipitation technique structure analysis of Mn–Zn ferrite using extended X-ray absorption fine structure  

Microsoft Academic Search

The tetrahedral\\/octahedral site occupancy of non-magnetic zinc ion, added to maximize the net magnetic moment of mixed ferrites has been found to depend on the method of preparation. In this paper, we qualitatively analyze the metal ion distribution in Mn–Zn ferrite particles prepared by co-precipitation and ceramic methods using extended X-ray absorption fine structure (EXAFS) technique. The results suggest that

B. Jeyadevan; K. Tohji; K. Nakatsuka; A. Narayanasamy

2000-01-01

147

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

148

Structural characterization of microwave-synthesized zinc-substituted cobalt ferrite nanoparticles  

Microsoft Academic Search

Microwave combustion technique modified by post treatment procedure is used to synthesize single-phase spinel ferrites of\\u000a cobalt, zinc, and substituted magnetic nanoparticles of typical size 390 Å. The post treatment does not alter the crystal\\u000a structure but increases the crystallinity. This is confirmed by powder x-ray diffraction and Fourier Transform Infrared (FTIR)\\u000a studies. Citric acid is used as a fuel.

Harshida Parmar; Rucha Desai; R. V. Upadhyay

2011-01-01

149

Effects of cobalt doping on the microstructure and magnetic properties of Mn–Zn ferrites prepared by the co-precipitation method  

Microsoft Academic Search

Mn–Zn ferrite nanoparticles with various amounts of cobalt doping have been synthesized by the co-precipitation method. The structure and morphology of the nanoparticles have been characterized by X-ray diffraction and transmission electron microscopy. The effects of cobalt ions on the crystallization behavior, lattice parameters and magnetic properties of Mn–Zn ferrites have been investigated. All the Co-doped ferrite nanoparticles calcined at

C. F. Zhang; X. C. Zhong; H. Y. Yu; Z. W. Liu; D. C. Zeng

2009-01-01

150

Effects of cobalt doping on the microstructure and magnetic properties of Mn-Zn ferrites prepared by the co-precipitation method  

Microsoft Academic Search

Mn-Zn ferrite nanoparticles with various amounts of cobalt doping have been synthesized by the co-precipitation method. The structure and morphology of the nanoparticles have been characterized by X-ray diffraction and transmission electron microscopy. The effects of cobalt ions on the crystallization behavior, lattice parameters and magnetic properties of Mn-Zn ferrites have been investigated. All the Co-doped ferrite nanoparticles calcined at

C. F. Zhang; X. C. Zhong; H. Y. Yu; Z. W. Liu; D. C. Zeng

2009-01-01

151

Bulk magnetic properties of Co-Zn ferrites prepared by the co-precipitation method  

Microsoft Academic Search

The alternating current (a.c.) susceptibility versus temperature and magnetization measurements are reported for the disordered\\u000a spinel ferrite system Zn\\u000a x\\u000a Co1-x\\u000a Fe2 O4 prepared by a wet chemical method before and after high temperature annealing. The low field a.c. susceptibility measurements\\u000a indicate that the low temperature synthesis of wet prepared Co-Zn ferrites aids the formation of spin-clusters and thereby\\u000a increases

P. B. Pandya; H. H. Joshi; R. G. Kulkarni

1991-01-01

152

Influence of the morphology of ferrite nanoparticles on the directed assembly into magnetically anisotropic hierarchical structures.  

PubMed

The effect of the morphology of ferrite nanoparticles on their assembly in a magnetic field was studied. Thin BaFe12O19 nanoplatelets were compared with isotropic, spherical or octahedral, CoFe2O4 nanoparticles, all of which were synthesized hydrothermally. The nanoplatelets and nanoparticles assembled into a variety of hierarchical structures from stable suspensions during the "drop deposition" and drying in a magnetic field. The alignment of the nanoparticles in the magnetic field was observed in situ with an optical microscope. The morphologies of the nanoparticles and the subsequent assemblies were observed with transmission and scanning electron microscopes, respectively. The magnetic properties of the nanoparticles and the assemblies were measured with a vibrating-sample magnetometer. The BaFe12O19 nanoplatelets aligned in the plane of the substrate and formed several-micrometers-thick, ordered films with a magnetic alignment of approximately 90%. The CoFe2O4 nanoparticles assembled into thick, dense columns with a height of several hundreds of micrometers and showed a magnetic alignment of up to 60%. The differences in the morphologies and the magnetic alignments between the BaFe12O19 and CoFe2O4 hierarchical structures could be explained in terms of the differences in the shape and magnetocrystalline structure of the specific nanoparticles. PMID:24841592

Lisjak, Darja; Jenuš, Petra; Mertelj, Alenka

2014-06-10

153

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

154

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

155

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

156

An overview of the structure and magnetism of spinel ferrite nanoparticles and their synthesis in microemulsions  

Microsoft Academic Search

In this review, we attempt to describe the structure of various spinel ferrites like zinc ferrite, nickel–zinc ferrite, manganese–zinc ferrite and cobalt ferrite. It also describes the important magnetic properties of these spinel ferrites. The focus then shifts to the use of microemulsions as nanoreactors for the synthesis of spinel ferrites. This work gives a short review on the various

Daliya S. Mathew; Ruey-Shin Juang

2007-01-01

157

Biocompatible mesoporous silica-coated superparamagnetic manganese ferrite nanoparticles for targeted drug delivery and MR imaging applications.  

PubMed

Multifunctional mesoporous silica-coated superparamagnetic manganese ferrite (MnFe2O4) nanoparticles (M-MSN) were synthesized and evaluated for targeted drug delivery and magnetic resonance imaging (MRI) applications. MnFe2O4 nanoparticles were prepared by solvothermal route and were silica-coated by surface silylation using sol-gel reactions. Subsequently, silylation was done using (3-aminopropyl)triethoxysilane in presence of a surfactant (CTAB), followed by selective etching of the surfactant molecules that resulted in amine-functionalized superparamagnetic nanoparticles (NH2-MSN). Further modification of the surface of the NH2-MSN with targeting (folate) or fluorescent (RITC) molecules resulted in M-MSN. The formation of the M-MSN was proved by several characterization techniques viz. XRD, XPS, HRTEM, FESEM, VSM, BET surface area measurement, FTIR, and UV-Vis spectroscopy. The M-MSN were loaded with anticancer drug Doxorubicin and the efficacy of the DOX loaded M-MSN was evaluated through in vitro cytotoxicity, fluorescence microscopy, and apoptosis studies. The in vivo biocompatibility of the M-MSN was demonstrated in a mice-model system. Moreover, the M-MSN also acted as superior MRI contrast agent owing to a high magnetization value as well as superparamagnetic behavior at room temperature. These folate-conjugated nanoparticles (FA-MSN) exhibited stronger T2-weighted MRI contrast towards HeLa cells as compared to the nanoparticles without folate conjugation, justifying their potential importance in MRI based diagnosis of cancer. Such M-MSN with a magnetic core required for MRI imaging, a porous shell for carrying drug molecules, a targeting moeity for cancer cell specificity and a fluorescent molecule for imaging, all integrated into a single system, may potentially serve as an excellent material in biomedical applications. PMID:24980623

Sahoo, Banalata; Devi, K Sanjana P; Dutta, Sujan; Maiti, Tapas K; Pramanik, Panchanan; Dhara, Dibakar

2014-10-01

158

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

159

Magnetic properties and composition range of non-stoichiometric m-type hexagonal ferrites prepared by ion exchange  

Microsoft Academic Search

Single crystals of Ba, Sr M-type hexagonal ferrites were prepared by ion exchange in Ba, Sr containing molten salts from single crystals of beta'' -ferrites. A fast diffusion of the divalent Ba2+, Sr2+ is observed leading to a non-stoichiometric M-type ferrite with chemical formula: Ba1+xFe10.5Co0.25O17+x (0 <= x <= 0.25). x depending on the exchange reaction time. Saturation magnetization ranges

O. Kalogirou; D. Samaras; A. C. Stergiou

1990-01-01

160

In vivo bio-distribution of intravenously injected Tc99 m labeled ferrite nanoparticles bounded with biocompatible medicals  

Microsoft Academic Search

In vivo bio-distribution of directly radioisotope (Tc-99 m) labeled with ferrite (Fe3O4) nanoparticles, conjugated with Poly(ethyelene glycol) (PEG), upon intravenous injection into rats was studied. The time evolution of bio-distribution of the radio-beads was investigated by analyzing the scintigrams monitored with a planar gamma camera. From the scintigraphic images, the PEG conjugated ferrite radiobeads have demonstrated a reduction of uptake

Chao-Ming Fu; Yuh-Feng Wang; Yu-Feng Guo; Tang-Yi Lin; Jainn-Shiun Chiu

2005-01-01

161

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

162

Preparation of chitin nanogels containing nickel nanoparticles.  

PubMed

In this work, we developed 120-150 nm sized nickel nanoparticles loaded chitin nanogels (Ni-Chitin NGs) by regeneration chemistry approach to investigate and determine its cytocompatibility and antibacterial activity against Staphylococcus aureus. The nickel nanoparticles were prepared by hydrothermal method. The prepared Ni-Chitin NGs were well characterized by SEM, FTIR, TG/DTA/DTG and XRD and the in vitro cytocompatibility was tested on A549 and L929 cells which showed that they are completely non-toxic. Ni-Chitin NGs showed better toxicity to the bacterial strains when compared to previous study with other nanoparticles using serial dilution method. The rhodamine labeled-Ni-Chitin NGs showed cellular localization on both L929 and A549 cells without perturbing their cellular constituents. These studies showed that the Ni-Chitin NGs could be used for various applications in biomedical filed. PMID:23911472

Kumar, N Ashwin; Rejinold, N Sanoj; Anjali, P; Balakrishnan, Avinash; Biswas, Raja; Jayakumar, R

2013-09-12

163

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

164

Large Tunability of Néel Temperature by Growth-Rate-Induced Cation Inversion in Mn-ferrite Nanoparticles  

SciTech Connect

The tuning of Neel temperature by greater than 100 K in nanoparticle Mn-ferrite was demonstrated by a growth-rate-induced cation inversion. Mn-ferrite nanoparticles, having diameters from 4 to 50 nm, were synthesized via coprecipitation synthesis. The Neel temperature (TN) increased inversely to the cation inversion parameter, {delta} (i.e., defined as (Mn1-{delta}Fe{delta})tet[Mn{delta}Fe2-{delta}]octO4). Concomitantly, TN increased with increased particle growth rate and particle size. These results unambiguously establish cation inversion as the dominant mechanism in modifying the superexchange leading to enhanced TN. The ability to tailor TN enables greater flexibility in applying nanoparticle ferrites in emerging technologies.

Yang, A.; Chinnasamy, C; Greneche, J; Chen, Y; Yoon, S; Hsu, K; Vittoria, C; Harris, V

2009-01-01

165

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

166

Processing of Nano-Crystallite Spinel Ferrite Prepared by Co-Precipitation Method  

NASA Astrophysics Data System (ADS)

Mn0.4Cu0.4Zn0.2Fe ferrite was synthesized by soft chemical approach called co-precipitation technique. The ferrite powder was calcined, compacted and sintered at 700°C and 800°C for 3 h. The initial permeability, density, grain size, Curie temperature and dc resistivity have been studied. X-ray diffraction (XRD) method confirmed the sample to be a single-phase spinel structure without unreacted constituents. The particle size was calculated from XRD spectrum using Scherrer's formula and found to be ~55 nm. Then, nanoparticles were observed with tunneling electron microscopy (TEM). Further, scanning electron micrograph (SEM) also confirmed nano-phase and the uniformity of the particles. The initial permeability values do not exhibit much variation with temperature, except near Curie temperature, where it falls sharply. The initial permeability is found to increase with the increase in sintering temperature. This is attributed to the increase in the grain size. Calculation of activation energy indicates that the given ferrite is p-type semiconductor. Mössbauer study of these samples shows superparamagnetic behavior, which also confirms the formation of nano-particles. Possible models and mechanisms contributing to these processes have been discussed.

Mathur, P.; Thakur, A.; Singh, M.

167

Microwave absorption properties of conducting polymer composite with barium ferrite nanoparticles in 12.4-18 GHz  

NASA Astrophysics Data System (ADS)

Conducting polymer nanocomposites of polyphenyl amine with barium ferrite nanoparticles (50-70nm) have been synthesized via emulsion polymerization. The complex permittivity, permeability, and microwave absorption properties of the composite were studied in the 12.4-18GHz (Ku band) frequency range. The composite has shown high shielding effectiveness due to absorption (SEA) of 28.9dB (˜99.9%), which strongly depends on dielectric loss, magnetic permeability, and volume fraction of barium ferrite nanoparticles. The high value of SEA suggests that these composites can be used as a promising radar absorbing materials.

Ohlan, Anil; Singh, Kuldeep; Chandra, Amita; Dhawan, S. K.

2008-08-01

168

Influence of synthesis method on structural and magnetic properties of cobalt ferrite nanoparticles  

Microsoft Academic Search

The Co–ferrite nanoparticles having a relatively uniform size distribution around 8 nm were synthesized by three different\\u000a methods. A simple co-precipitation from aqueous solutions and a co-precipitation in an environment of microemulsions are low\\u000a temperature methods (50 °C), whereas a thermal decomposition of organo-metallic complexes was performed at elevated temperature\\u000a of 290 °C. The X-ray diffractometry (XRD) showed spinel structure, and the high-resolution

Sašo Gyergyek; Darko Makovec; Alojz Kodre; Iztok Ar?on; Marko Jagodi?; Miha Drofenik

2010-01-01

169

Microwave resonant and zero-field absorption study of pure and doped ferrite nanoparticles  

Microsoft Academic Search

Microwave absorption was studied for magnetic nanoparticles of Fe3O4 (A) prepared by co-precipitation and Ni0.35Cu0.15Zn0.5Fe2O4 (B) nanoparticles prepared by the sol–gel combustion method at different temperature. In all cases only one ferromagnetic resonance line was observed which indicated that the materials were magnetically uniform. The linewidths were large mainly because of the wide variations in particle sizes, shapes and orientations.

G. V. Kurlyandskaya; S. M. Bhagat; S. E. Jacobo; J. C. Aphesteguy; N. N. Schegoleva

2011-01-01

170

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

171

Productive encounter: molecularly imprinted nanoparticles prepared using magnetic templates.  

PubMed

Synthesis of core-shell nanoparticles by surface initiated reversible addition fragmentation chain transfer polymerization in presence of a chiral template conjugated to magnetic nanoparticles is reported. The approach leads to imprinted nanoparticles featuring enantioselectivity and enhanced affinity compared to nanoparticles prepared using free template. PMID:24983025

Berghaus, Melanie; Mohammadi, Reza; Sellergren, Börje

2014-08-18

172

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

173

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

174

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

175

Synthesis, magnetic and optical properties of core/shell Co1- x Zn x Fe2O4/SiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

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.

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

2011-07-01

176

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

177

Preparation and characterization of functionalized aluminum nanoparticles  

NASA Astrophysics Data System (ADS)

Aluminum nanocomposite materials have been prepared by treating commercially available aluminum powders with long-chain perfluorinated carboxylic acids. The acid coated aluminum qualitatively shows enhanced burning compared to the same aluminum powder that was not treated with the acid. This preparation method will allow for the large scale production of air-stable, passivated aluminum nanoparticles. Aluminum nanocomposite materials with size ranges less than 500 nm have been prepared with various surface passivation/functionalization schemes that mitigate aluminum oxide effects and reduce the fuel-oxidizer distance to the molecular level. These materials have been characterized to understand the changes in particle size and morphology that occur with different preparation schemes. TGA, XPS and IR results are presented.

Horn, Jillian M.; Lightstone, James; Carney, Joel; Jouet, Jason

2012-03-01

178

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

179

Preparation and investigation of potentiality of different soft ferrites for hyperthermia applications  

SciTech Connect

Water-based ferrofluids of substituted ferrites Fe{sub 1-x}Mn{sub x}Fe{sub 2}O{sub 4} (0{<=}x{<=}1) have been prepared by the co-precipitation method and characterized. Particles are superparamagnetic with an average particle size of about 10-12 nm. The specific absorption rate (SAR) was measured by calorimetric measurement at a frequency of 300 kHz and a field of 10-45 kA/m. The variation of SAR and magnetization of Fe{sub 1-x}Mn{sub x}Fe{sub 2}O{sub 4} with Mn concentration shows similar dependence. Innocuousness studies of MnFe{sub 2}O{sub 4} ferrofluids to the living cells have been carried out with BHK-21 cells. In vitro studies showed that threshold biocompatible concentration is dependent on the nature of ferrites and coating.

Giri, Jyotsnendu; Pradhan, Pallab; Sriharsha, T.; Bahadur, D. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Mumbai-400076 (India); School of Bio-science and Bio-engineering, Indian Institute of Technology, Bombay, Mumbai-400076 (India); Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology, Bombay, Mumbai-400076 (India)

2005-05-15

180

Iron-based soft magnetic composites with Mn-Zn ferrite nanoparticles coating obtained by sol-gel method  

NASA Astrophysics Data System (ADS)

This paper focuses on iron-based soft magnetic composites which were synthesized by utilizing Mn-Zn ferrite nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm, were obtained via the sol-gel method. Scanning electron microscopy, energy dispersive X-ray spectroscopy and distribution maps show that the iron particle surface is covered with a thin layer of Mn-Zn ferrites. Mn-Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced imaginary permeability, increased electrical resistivity and a higher operating frequency of the synthesized magnets. Mn-Zn ferrite coated samples have higher permeability and lower magnetic loss when compared with the non-magnetic epoxy resin coated compacts. The real part of permeability increases by 33.5% when compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature on crystalline phase formation and on the magnetic properties of the Mn-Zn ferrite were investigated via X-ray diffraction and a vibrating sample magnetometer. Ferrites decomposed to FeO and MnO after annealing above 400 °C in nitrogen; thus it is the optimum annealing temperature to attain the desired permeability.

Wu, Shen; Sun, Aizhi; Xu, Wenhuan; Zhang, Qian; Zhai, Fuqiang; Logan, Philip; Volinsky, Alex A.

2012-11-01

181

Influence of calcium ions on the structural and magnetic properties of Cd-Mg ferrites nanoparticles.  

PubMed

Cadmium magnesium ferrites doped with calcium having the chemical formula Cd0.5Mg0.5-x Ca(x)Fe2O4 (0.0 < or = x < or = 0.3) were prepared by the Co-precipitation method. X-ray diffraction analysis confirmed the formation of a single phase with spinel crystal structure for the samples. The lattice parameter is determined for each composition and has been found to increase from 8.505 angstroms to 8.626 angstroms with increasing calcium concentration. Cation distribution for the studied ferrite system is proposed in terms of the structural and magnetic properties by means of X-ray diffraction (XRD), infrared spectroscopy (IR), vibrating sample magnetometer (VSM) and is found to be reliable. The experimental and theoretical lattice constants show the same trend with increasing calcium concentration indicating the validity of the proposed cation distribution. The analysis of infrared spectra indicates the presence of splitting in the absorption band which may be attributed to the presence of small amounts of Fe2+ ions in the ferrite system. The appearance of a shoulder around 700 cm(-1) suggests the presence of calcium ions in the tetrahedral site. The addition of non magnetic calcium ions in the ferrites suppressed the A-interaction and developed a B-B interaction, which is reflected in reducing the saturation magnetization in the present samples. The coercive field (H(c)) is also found to increase by increasing of Ca2+ concentration and has been explained on the bases of direct relationship with anisotropy constant. PMID:23035443

Zaki, H M; Al-Heniti, S

2012-09-01

182

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

183

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

184

A Low-Temperature Method to Synthesize Co-Substituted Mn-Zn Ferrite Nanoparticles with Distinct Magnetic Properties  

Microsoft Academic Search

Mn-Zn ferrite nanoparticles about 15 nm with various amounts of Co substituting for Mn were synthesized in microemulsion at 50°C. The samples were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscope, and vibrating sample magnetometer. The experimental results indicate the formula for all samples can be derived as CoxMn1?xZn0.5Fe1.504, and the presence of single-phase spinel ferrite is in

Youxian Zhang; Jiaona Fan; Qian Li; Yongtao An; Chuanhui Liang; Xueqin An

2010-01-01

185

Polyoxometalates acid treatment for preparing starch nanoparticles.  

PubMed

In this article, a new way of preparing starch-based nanoparticles (SNPs) with high yields by a polyoxometalates acid treatment is presented. The particle morphology, mean size and size distribution of the obtained SNPs are characterized using a dynamic light scattering (DLS) and scanning electron microscope (SEM). By changing parameters such as temperature, concentration of polyoxometalates and treating time the size of SNPs can be controlled. In addition, there are no changes in the structures of the starch granules as confirmed by IR or (1)H NMR. Freeze-dried SNPs are amorphous as characterized by wide-angle X-ray diffraction (WXRD). PMID:25129776

Chen, Li; Zhang, Zhe; Zhao, Ziwei; Wang, Xiaohong; Chen, Xuesi

2014-11-01

186

Competing magnetic interactions in nickel ferrite nanoparticle clusters: Role of magnetic interactions  

NASA Astrophysics Data System (ADS)

The magnetic behavior of nickel ferrite nanoparticles of different sizes was studied by annealing nickel ferrite powders at temperatures ranging from 300 to 900 °C. Transmission electron microscopy studies show that the average particle sizes change from ˜8 to ˜120 nm with increasing annealing temperatures. The x-ray diffraction patterns of the annealed samples reveal that a single phase is retained. Hysteresis measurements performed up to a field of 10 kOe show a tendency toward saturation. The saturation magnetization is found to increase with annealing temperature (particle size) with the magnetization tending toward the bulk value for powders annealed at 900 °C. Zero field cooled-field cooled measurements performed at 0.5 kOe indicate the presence of a superparamagnetic phase up to an annealing temperature of 700 °C with blocking temperatures in the range of 150-330 K. Numerical simulations are carried out using an interacting model of an array of single domain magnetic particles to explain the change in the magnetic behavior of the samples with annealing temperature and to estimate the anisotropy of the system. Our studies indicate that the observed magnetic behavior can be explained by the changes in the anisotropy of the system and the dominance of the short range interparticle exchange interactions over the long range dipolar interactions with increasing particle sizes. This change in the interaction profile is further confirmed by the Henkel plots for the particles annealed at different temperatures.

Malik, Rakesh; Annapoorni, S.; Lamba, Subhalakshmi; Sharma, Parmanand; Inoue, Akihisa

2008-09-01

187

Structural characterization of microwave-synthesized zinc-substituted cobalt ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Microwave combustion technique modified by post treatment procedure is used to synthesize single-phase spinel ferrites of cobalt, zinc, and substituted magnetic nanoparticles of typical size 390 Å. The post treatment does not alter the crystal structure but increases the crystallinity. This is confirmed by powder x-ray diffraction and Fourier Transform Infrared (FTIR) studies. Citric acid is used as a fuel. The fresh synthesized sample shows an impurity phase in x-ray and in FTIR. This is due to the unreacted citrate molecule adsorbed on the particle surface. It is shown that by treating the sample with 0.1 M HCl, we can eliminate the impurity phase, and one can obtain a pure single phase. The magnetization at 8 kOe increases by nearly 8% after the removal of impurity. In order to remove surface adsorbed OH- ion, samples are treated with NaCl and heated to 200°C for four hours. The XRD result indicates that after the treatment neither the crystallite size nor the distribution changes, but it removes OH- ion. This is also confirmed by FTIR analysis. Thus, this modified technique can be used to synthesize pure nanocrystalline samples of spinel ferrites.

Parmar, Harshida; Desai, Rucha; Upadhyay, R. V.

2011-07-01

188

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

189

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

190

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

191

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

192

Preparation and characterization of uniform near IR polystyrene nanoparticles.  

PubMed

Biomaterials for in vivo fluorescence imaging are required to be biocompatible, nontoxic, photostable and highly fluorescent. Fluorescence must be in the near infrared (NIR) region of the electromagnetic spectrum to avoid absorption and autofluorescence of endogenous tissues. NIR fluorescent polystyrene nanoparticles may be considered ideal biomaterials for in vivo imaging applications. These NIR nanoparticles were prepared by a swelling process of polystyrene template nanoparticles with a hydrophobic NIR dye dissolved in a water-miscible swelling solvent, a method developed for preparation of nonbiodegradable nanoparticles, for NIR fluorescent bioimaging applications. This method overcomes common problems that occur with dye entrapment during nanoparticle formation such as loss of fluorescence and size polydispersity. Fluorescence intensity of the nanoparticles was found to be size dependent, and was optimized for differently sized nanoparticles. The resulting NIR nanoparticles were also found to be more fluorescent and highly photostable compared to the free dye in solution, showing their potential as biomaterials for in vivo fluorescence imaging. PMID:24460556

Pellach, Michal; Margel, Shlomo

2014-01-01

193

Preparation of magnetic chitosan nanoparticles and immobilization of laccase  

Microsoft Academic Search

The magnetic chitosan nanoparticles were prepared by reversed-phase suspension method using Span-80 as an emulsifier, glutaraldehyde\\u000a as cross-linking reagent. And the nanoparticles were characterized by TEM, FT-IR and hysteresis loop. The results show that\\u000a the nanoparticles are spherical and almost superparamagnetic. The laccase was immobilized on nanoparticles by adsorption and\\u000a subsequently by cross-linking with glutaraldehyde. The immobilization conditions and characterizations

Hua Fang; Jun Huang; Liyun Ding; Mingtian Li; Zhao Chen

2009-01-01

194

Preparation and microstructure of spinel zinc ferrite ZnFe 2 O 4 by Coprecipitation method  

Microsoft Academic Search

Spinel zinc ferrites ZnFe2O4, prepared by co-precipitation method using the zinc nitrate Zn(NO3)2·6H2O and ferric nitrate Fe(NO3)3·2H2O as the raw materials, were characterized by the thermo gravimetric analysis (TG) and differential scanning calorimeter (DSC),\\u000a X-ray diffraction (XRD) and scanning electron microscope (SEM). The influence of synthesis conditions, such as Zn\\/Fe molar\\u000a ratio, pH value, the sintering temperature and time, on

Ping Ren; Junxi Zhang; Huiyong Deng

2009-01-01

195

Preparation of barium ferrite films with high Fe\\/Ba ratio by sol–gel method  

Microsoft Academic Search

Hexagonal BaFe12O19 ferrite (BaM) thin films were prepared on Si (100) substrate successfully by sol–gel technology and post annealing. The results\\u000a showed the BaM phase can be formed and crystallized into c-axis textured grains even when the Fe\\/Ba ratio of the precursor\\u000a varied from 6.5 to 9.5. However, the behavior of the saturation magnetization (M\\u000a s) and intrinsic coercivity (H

Hui Li; Jie Huang; Qingfeng Li; Xiaodong Su

2009-01-01

196

A Study of the Combustion Method to Prepare Fine Ferrite Particles  

Microsoft Academic Search

A combustion synthesis method was adapted for the efficient preparation of pure barium ferrite particles (BaFe2O4and BaFe12O19). It is based on the exothermic reaction of the corresponding metal nitrates with a reducing agent (ODH or TFTA) and yields extremely fine-grained ashes that readily convert into pure BaFe2O4and BaFe12O19when treated thermally. The composition and microstructure of the so-obtained materials were studied

S. Castro; M. Gayoso; C. Rodr??guez

1997-01-01

197

Study on initial permeability of Ni-Zn ferrite films prepared by the spin spray method  

NASA Astrophysics Data System (ADS)

Initial permeability of Ni-Zn ferrite films prepared by spin spray chemical plating is investigated. They exhibit a semi-hard magnetization process but have relatively high permeability with explicit dual peak resonance loss in the GHz frequency range. In this study, it turned out that the loss is determined mainly by the two magnetic parameters, namely, the crystalline anisotropy and a uniaxial anisotropy induced by Co addition. Measurement of permeability in an external DC field clarified that the semi-hard wall coercivity fixes the spin direction of residual magnetization state and, consequently, gives rise to uniaxial permeability with dependence of its direction on the previously applied DC field.

Shimada, Yutaka; Matsushita, Nobuhiro; Abe, Masanori; Kondo, Koichi; Chiba, T.; Yoshida, Shigeyoshi

2004-07-01

198

Microwave absorption properties of Ba M-type ferrite prepared by a modified coprecipitation method  

Microsoft Academic Search

The electromagnetic wave absorption properties were investigated in the Co–Ti substituted Ba M-type hexagonal ferrites (BaFe9.5(Co1?yTiy)2.5O19 (y=0.4–0.8)), which were prepared by a modified coprecipitation method. This modified chemical coprecipitation method was the combination of coprecipitation and synthesis from a salt melt. The Ba9.5(Co0.4Ti0.6)2.5O19 sample, which was sintered at 1423K for 5h with a Bi2O3 addition of 2wt%, exhibited high permeability

Satoshi Sugimoto; Kazuaki Haga; Toshio Kagotani; Koichiro Inomata

2005-01-01

199

Study of hard-soft magnetic ferrite films prepared by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Soft magnetic Mg0.1Ni0.3Zn0.6Fe2O4 and hard magnetic BaFe12O19 bulk nanocrystalline ferrites were synthesized using the sol-gel auto-combustion method, and were used as targets to deposit soft-hard thin films by the pulsed laser deposition (PLD) method. Various soft-hard thin films with different preparation conditions were deposited on Si (100) substrate, which can be effectively utilized to get better magnetic properties. The prepared films were characterized by the X-ray diffraction (XRD), atomic force microscopy (AFM) and magnetic measurements. XRD confirms the presence of soft and hard phases in the thin films. Coercivity of the prepared films ranges from 1.67 to 2.66 kA/m. AFM images show clustering of grains at the film surface with a characteristic columnar growth.

Satalkar, M.; Kane, S. N.; Ghosh, A.; Raghuvanshi, S.; Tapkir, P.; Ghodke, N.; Phase, D. M.; Chaudhary, R. J.; Pasko, A.; LoBue, M.; Mazaleyrat, F.

2014-09-01

200

Preparation and characterization of magnetic nanoparticles with chitosan coating  

Microsoft Academic Search

Magnetic chitosan nanoparticles were prepared by the suspension cross-linking technique for use in the application of magnetic carrier technology. The Fe3O4 magnetic nanoparticles were synthesized by co-precipitation of FeCl2 and FeCl3 solution in base medium for using in the preparation of the magnetic chitosan. The morphological and magnetic properties of the magnetic nanoparticles were characterized by different techniques (TEM, XRD,

Doan Thi Kim Dung; Tran Hoang Hai; Le Hong Phuc; Bui Duc Long; Le Khanh Vinh; Phan Nha Truc

2009-01-01

201

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

202

Magnetic properties and composition range of non-stoichiometric m-type hexagonal ferrites prepared by ion exchange  

NASA Astrophysics Data System (ADS)

Single crystals of Ba, Sr M-type hexagonal ferrites were prepared by ion exchange in Ba, Sr containing molten salts from single crystals of ?? -ferrites. A fast diffusion of the divalent Ba 2+, Sr 2+ is observed leading to a non-stoichiometric M-type ferrite with chemical formula: Ba 1+ xFe 10.5Co 0.25O 17+ x (0 ? x ? 0.25). x depending on the exchange reaction time. Saturation magnetization ranges from 19 to 64 emu/g depending on exchange conditions. The Curie temperature is (470 ± 5)°C. An easy axis direction ( Ms ? c) has been determined in all cases. The observed anisotropy is considerably lower than that of M ferrite. The calculated anisotropy constants are, in 10 6 erg/cm 3, K1 = 0.8 and K2 = 1.0 at room temperature.

Kalogirou, O.; Samaras, D.; Stergiou, A. C.

1990-10-01

203

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

204

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

205

Preparation, magnetic and electromagnetic properties of polyaniline/strontium ferrite/multiwalled carbon nanotubes composite  

NASA Astrophysics Data System (ADS)

Strontium ferrite particles were firstly prepared by sol-gel method and self-propagating synthesis, and then the polyaniline/strontium ferrite/multiwalled carbon nanotubes composites were synthesized through in situ polymerization approach. Structure, morphology and properties of the composite were characterized by various instruments. XRD analysis shows that the output of PANI increases with the increase of the content of MWCNTs, due to the large surface area of MWCNTs. Because of the coating of PANI, the outer diameter of MWCNTs increases from 10 nm to 20-40 nm. The electrical conductivity of the composites increases with the amount increase of MWCNTs and reaches 7.2196 S/cm in the presence of 2 g MWCNTs. The coercive force of the composites prepared with 2 g MWCNTs is 7457.17 Oe, which is much bigger than that of SrFe12O19 particles 6145.6 Oe, however, both the saturation magnetization and the remanent magnetization of the composite become much smaller than those of SrFe12O19 particles. The electromagnetic properties of the composite are excellent in the frequency range of 2-18 GHz, which mainly depend on the dielectric loss in the range of 2-9 GHz, and mainly on the magnetic loss in the range of 9-18 GHz.

Li, Yuqing; Huang, Ying; Qi, Shuhua; Niu, Lei; Zhang, Yinling; Wu, Yanfei

2012-02-01

206

Microwave absorption properties of Ba M-type ferrite prepared by a modified coprecipitation method  

NASA Astrophysics Data System (ADS)

The electromagnetic wave absorption properties were investigated in the Co-Ti substituted Ba M-type hexagonal ferrites (BaFe 9.5(Co 1-yTi y) 2.5O 19 ( y=0.4-0.8)), which were prepared by a modified coprecipitation method. This modified chemical coprecipitation method was the combination of coprecipitation and synthesis from a salt melt. The Ba 9.5(Co 0.4Ti 0.6) 2.5O 19 sample, which was sintered at 1423 K for 5 h with a Bi 2O 3 addition of 2 wt%, exhibited high permeability ( ?r max?=25 and ?r? at 1 GHz=10). This sample also showed a good microwave absorption property (reflection loss: RL<-20 dB) with a small matching thickness ( dm) of 3.1 mm at 0.65 GHz. It is concluded that the Ba M-type ferrite prepared by the modified coprecipitation method has a possibility to become a candidate for thinner microwave absorbers in the gigahertz range.

Sugimoto, Satoshi; Haga, Kazuaki; Kagotani, Toshio; Inomata, Koichiro

2005-04-01

207

Effects of cobalt doping on the microstructure and magnetic properties of Mn-Zn ferrites prepared by the co-precipitation method  

NASA Astrophysics Data System (ADS)

Mn-Zn ferrite nanoparticles with various amounts of cobalt doping have been synthesized by the co-precipitation method. The structure and morphology of the nanoparticles have been characterized by X-ray diffraction and transmission electron microscopy. The effects of cobalt ions on the crystallization behavior, lattice parameters and magnetic properties of Mn-Zn ferrites have been investigated. All the Co-doped ferrite nanoparticles calcined at 1150 °C possess a simple spinel structure and have an approximately spherical shape. The lattice parameters increase almost linearly with increasing Co content. The studies of magnetic properties show that the saturation magnetization Ms strongly depends on the Co content, having a maximum Ms value of 73 emu/g at a Co content of 1.0 at%, and all the Co-doped ferrites, with the average crystallite sizes ranging from 24.5 to 27.0 nm, exhibit superparamagnetism at room temperature.

Zhang, C. F.; Zhong, X. C.; Yu, H. Y.; Liu, Z. W.; Zeng, D. C.

2009-08-01

208

Synthesis and Thermal Stability of Polycrystalline New Divalent ??- and ?-Ferrites Prepared by Ion Exchange  

NASA Astrophysics Data System (ADS)

Using ion-exchange chemistry the divalent cations Ba 2+, Sr 2+, Ca 2+, Mg 2+ Cd 2+, Pb 2+, Co 2+, Zn 2+, Mn 2+, Fe 2+, and Sn 2+ have been substituted for K + in polycrystalline CdO-stabilized K-??-ferrite samples. Ba, Sr, Ca, Mg, Pb, and Cd ion exchange led to the synthesis of new materials, the divalent M2+ -??-ferrites ( M = Ba, Sr, Ca, Mg) and M2+ -?-ferrites ( M = Cd, Pb), respectively, Co 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 ?-Fe 2O 3. The thermal stability of the new divalent ??- and ?-ferrites was studied either by high-temperature exchange reactions or by air annealing of the exchanged products. Ba- and Sr-??-ferrites and Pb-?-ferrite converted to M-type hexagonal ferrites with the magnetoplumbite structure. Mg-??-ferrite decomposed to a spinel-type Mg-ferrite, and Ca-??-ferrite and Cd-?-ferrite decomposed to ?-Fe 2O 3. Composition, lattice parameters, SEM photographs, and magnetic properties of the ferrites formed are given. The magnetic susceptibilities of the divalent ??- or ?-ferrites have values between 0.63 and 1.14 × 10 -4 emu/g · Oe at room temperature.

Kalogirou, O.

1993-02-01

209

Preparation and characterization of magnetic nanoparticles with chitosan coating  

NASA Astrophysics Data System (ADS)

Magnetic chitosan nanoparticles were prepared by the suspension cross-linking technique for use in the application of magnetic carrier technology. The Fe3O4 magnetic nanoparticles were synthesized by co-precipitation of FeCl2 and FeCl3 solution in base medium for using in the preparation of the magnetic chitosan. The morphological and magnetic properties of the magnetic nanoparticles were characterized by different techniques (TEM, XRD, VSM, FTIR, etc.). The magnetic properties of chitosan - magnetic nanoparticles were analyzed by VSM, and MS around 15 emu/g.

Dung, Doan Thi Kim; Hoang Hai, Tran; Phuc, Le Hong; Long, Bui Duc; Khanh Vinh, Le; Nha Truc, Phan

2009-09-01

210

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

211

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

212

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

213

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

214

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

215

Dielectric study of Al3+ substituted Fe3O4 ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Al3+ substituted nanoparticles i.e., FeAlxFe2-xO4(x = 0.2, 0.4, 0.6) have been synthesized by the chemical co precipitation method. Crystalline phase of synthesized particles was confirmed by XRD pattern. Particle size of as obtained samples was found in the range of 24-34 nm. Dielectric loss (tan ?, dielectric permittivity (??) and ac conductivity (?ac) were evaluated as a function of frequency, composition and temperature using impedance analyzer in the frequency range of (1000 Hz-5 MHz) and temperature range of (300-473 K). AC conductivity (?ac) was found to decrease with increase in Al3+ doping which has been explained on the basis of hopping mechanism. The variation of dielectric loss (tan ?, dielectric permittivity (??), ac conductivity (?ac) with temperature and frequency can be explained on the basis of Maxwell-Wagner type of interfacial polarization and hopping mechanism between ferrous and ferric ions at the octahedral site. DC electrical resistivity was found to decrease with increasing temperature indicating that the substituted ferrites have semiconductor like behavior. Activation energy was found to increase with increasing Al3+ ion content.

Kumari, N.; Kumar, Vinod; Singh, S. K.

2014-07-01

216

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

217

Cytotoxicity of Gold Nanoparticles Prepared by Ultrasonic Spray Pyrolysis  

Microsoft Academic Search

The aim of this work was to study the cytotoxicity of different fractions of gold nanoparticles prepared by ultrasonic spray pyrolysis from gold scrap. The target cells were rat thymocytes, as a type of nonproliferating cells, and L929 mouse fibroblasts, as a type of continuous proliferating cells. Fractions 1 and 2, composed of pure gold nanoparticles, as determined by scanning

R. Rudolf; B. Friedrich; S. Stopi?; I. Anžel; S. Tomi?; M. ?oli?

2012-01-01

218

Adsorption of Cu2+ ions using chitosan-modified magnetic Mn ferrite nanoparticles synthesized by microwave-assisted hydrothermal method  

NASA Astrophysics Data System (ADS)

Chitosan-modified Mn ferrite nanoparticles were synthesized by a one-step microwave-assisted hydrothermal method. These Mn ferrite magnetic composite nanoparticles were employed to absorb Cu2+ ions in water. XRD verified the spinel structure of the MnFe2O4 nanoparticles. Chitosan modification does not result in any phase change of MnFe2O4. FTIR and zeta potentials curves for all samples suggest that chitosan can be successfully coated on the Mn ferrites. TEM characterization showed that the modified MnFe2O4 nanoparticles have a cubic shape with a mean diameter of ?100 nm. For adsorption behavior, the effects of experiment parameters such as solution pH value, contact time and initial Cu2+ ions concentration on the adsorption efficiency were systematically investigated. The results showed that increasing solution pH value and extending contact time are favorable for improving adsorption efficiency. Especially, adsorption efficiency can reach up to 100% and 96.7% after 500 min adsorption at pH 6.5 for the solutions with initial Cu2+ ions concentration of 50 mg/L and 100 mg/L. Adsorption data fits well with the Langmuir isotherm models with a maximum adsorption capacity (qm) and a Langmuir adsorption equilibrium constant (K) of 65.1 mg/g and 0.090 L/mg, respectively. The adsorption kinetic agrees well with pseudo second order model with the pseudo second rate constants (K2) of 0.0468 and 0.00189 g/mg/min for solutions with initial Cu2+ ions of 50 and 100 mg/L, respectively.

Meng, Yuying; Chen, Deyang; Sun, Yitao; Jiao, Dongling; Zeng, Dechang; Liu, Zhongwu

2015-01-01

219

Adsorption of sulfur dioxide by CoFe2O4 spinel ferrite nanoparticles and corresponding changes in magnetism.  

PubMed

Adsorption of sulfur dioxide on 10 nm CoFe(2)O(4) spinel ferrite nanoparticles was examined. Adsorption loadings of sulfur dioxide at breakthrough conditions were determined to be approximately 0.62 mol/kg, which is significant given the 150 m(2)/g surface area of the nanoparticles. Adsorption proceeds through a chemisorption mechanism with sulfur dioxide forming a sulfate upon adsorption on the particle surface, which leads to a 23% decrease in the remnant magnetization, a 20% decrease in the saturation magnetization, and a 9% decrease in the coercivity of the magnetic nanoparticles. Adsorbent materials that provide a magnetic signal when adsorption occurs could have broad implications on adsorption-based separations. PMID:22400990

Glover, T Grant; Sabo, Daniel; Vaughan, Lisa A; Rossin, Joseph A; Zhang, Z John

2012-04-01

220

Novel Methods of Lipidic Nanoparticle Preparation and Drug Loading  

NASA Astrophysics Data System (ADS)

In improving cancer chemotherapy, lipidic nanoparticle systems for drug delivery, such as liposomes and emulsions, have received much attention because they are capable of delivering their drug payload selectively to cancer cells and of circulating for a long period in the bloodstream. In addition, lipidic nanoparticles have been examined for use in gene delivery as a non-viral vector. Preparation methods of particles and drug loading methods are crucial for the physicochemical properties of nanoparticles, which are the key aspects for pharmaceutical applications. This review describes new preparation methods for nanoparticles and a loading method for drugs using nanotechnology, including an evaluation of nanoparticles from the point of drug release for applications in cancer therapy and gene delivery.

Maitani, Y.

2013-09-01

221

Preparation of Magnetic Chitosan Nanoparticles for Diverse Biomedical Applications  

NASA Astrophysics Data System (ADS)

Polymeric nanoparticles with magnetic properties can be potentially used in many fields such as biotechnology, separation processes, optoelectronic, catalysts and/or sensors, medical diagnosis and therapy. In this respect, biopolymers give promising trends due to their excellent biocompatibility and biodegradability. Therefore in this study, magnetic chitosan/Fe3O4 nanoparticles were prepared according to the procedure based on the ionic gelation of chitosan with tripolyphosphate anions. The formation of the particles was a result of the interaction between the negatively charged groups of the tripolyphosphate and the positively charged amino groups of chitosan. The prepared samples were observed by atomic force microscopy to obtain information about the morphology. The mean particle size of the nanoparticles was determined by dynamic light scattering measurements. Nanoparticles were spherical in shape with a particle size range of about 250-400 nm according to obtained data. Magnetic properties of the nanoparticles were determined by using ESR and VSM.

Kavaz, D.; Çirak, T.; Öztürk, E.; Bayram, C.; Denkba?, E. B.

222

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

223

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

PubMed

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. PMID:25554363

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

2015-01-22

224

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

225

Photosensitizer loaded HSA nanoparticles. I: Preparation and photophysical properties.  

PubMed

Photodynamic therapy (PDT) is a promising option in the treatment of cancer. Efficient photosensitizers are available but many of them have insufficient physico-chemical properties for parenteral application. We have established nanoparticles consisting of human serum albumin (HSA) as a drug carrier system for 5,10,15,20-tetrakis(m-hydroxyphenyl)porphyrine (mTHPP) and 5,10,15,20-tertrakis(m-hydroxyphenyl)chlorin (mTHPC), two well-known photosensitizers. Nanoparticle loading was performed in water/ethanol mixtures in the presence of dissolved HSA acting as solubilizer for photosensitizers. The HSA concentration was optimized to exclude precipitation in the nanoparticle suspension and to increase binding to nanoparticles. Additionally, the influence of pH and incubation time on drug adsorption was investigated. A freeze drying method was established for mTHPC loaded nanoparticles and the storage stability of the freeze dried formulation was tested. PDT related photophysical parameters of drug loaded HSA nanoparticles, especially singlet oxygen generation, are presented. Both preparations were able to generate singlet oxygen with low quantum yield. In contrast, efficient singlet oxygen generation was obtained when Jurkat cells were incubated with mTHPP and mTHPC loaded HSA nanoparticles. This indicates that the photosensitizer molecules were successfully released from the nanoparticles that were taken up by the cells. Therefore, the efficiency of HSA nanoparticles as drug carriers for photosensitizers was proven under in vitro conditions. PMID:20417701

Wacker, Matthias; Chen, Kuan; Preuss, Annegret; Possemeyer, Karin; Roeder, Beate; Langer, Klaus

2010-06-30

226

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....

227

Adiabatic pulse preparation for imaging iron oxide nanoparticles.  

PubMed

Superparamagnetic iron oxide nanoparticles produce changes in the surrounding microscopic magnetic field. A method for generating contrast based on the application of an adiabatic preparation pulse and the failure of the adiabatic condition surrounding the nanoparticles is introduced in this article. Images were obtained in the presence and absence of an adiabatic preparation pulse and the difference was obtained. With the use of an adiabatic full passage pulse, the contrast in the difference image depends linearly on iron concentration up to 1 mM. The use of an adiabatic zero passage pulse resulted in higher sensitivity to nanoparticles compared to the adiabatic full passage, while maintaining linear concentration dependence to 0.1 mM. This technique was shown to be insensitive to magnetization transfer and B(0) inhomogeneity. With its linearity with iron concentration and insensitivity to changes in the main magnetic field, the new method is well suited for quantitative iron oxide nanoparticle imaging. PMID:22213366

Harris, Steven S; Mao, Hui; Hu, Xiaoping P

2012-04-01

228

Preparation of Magnetic Chitosan Nanoparticles for Diverse Biomedical Applications  

Microsoft Academic Search

Polymeric nanoparticles with magnetic properties can be potentially used in many fields such as biotechnology, separation\\u000a processes, optoelectronic, catalysts and\\/or sensors, medical diagnosis and therapy. In this respect, biopolymers give promising\\u000a trends due to their excellent biocompatibility and biodegradability. Therefore in this study, magnetic chitosan\\/Fe3O4 nanoparticles were prepared according to the procedure based on the ionic gelation of chitosan with

D. Kavaz; T. Çirak; E. Öztürk; C. Bayram; E. B. Denkba?

2008-01-01

229

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

230

Anhydride functionalised calcium ferrite nanoparticles: a new selective magnetic material for enrichment of lead ions from water and food samples.  

PubMed

In this research a sonochemistry route for manufacture of uniform nanocrystalline CaFe2O4 and its anhydride functionalisation were reported. The potential of raw and modified material as a magnetically separable sorbent in selective enrichment of lead ions from water and food samples is outlined. This material was characterised using FT-IR, XRD, SEM and VSM techniques. The SEM and VSM results indicated that the calcium ferrite nanoparticles are sphere-like particles possessing superparamagnetic properties with an average diameter of 40 nm. Various analytical parameters, including pH, contact time, type and concentration of eluent, adsorption capacity, sample volume and interference of ions, were optimised. Following a modification by anhydride, calcium ferrite selectivity toward lead ions was raised more than twofold compared to the unmodified nanoparticles. Finally a pre-concentration procedure was applied for determination of trace Pb(II) in canned tuna fish, canned tomato paste, parsley, milk and well-water samples with satisfactory results. PMID:25306327

Pirouz, Mojgan Jafari; Beyki, Mostafa Hossein; Shemirani, Farzaneh

2015-03-01

231

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

232

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

233

Magnetic properties of Sr-Zn system W-type hexagonal ferrite magnets prepared by new manufacturing method  

Microsoft Academic Search

Sr-Zn system W-type hexagonal ferrite magnets were prepared by a novel manufacturing method of SrO addition after semisintering treatment, and without atmosphere control. It was found that this process was very useful in stabilizing the W-type hexagonal structure. The optimum condition of making magnets and some properties of typical specimens are as follows: the chemical analysis composition is Sr2+ 1.248Zn2+

H. Yamamoto; T. Nakajima; D. Yamada

1992-01-01

234

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

E-print Network

magnetic properties [1-3], associated to low cost of production, chemical stability and bio compatibility]. In this work, we have developed a simple one pot solvothermal synthesis method to obtain cobalt ferrites

Paris-Sud XI, Université de

235

Synthesis and investigation of magnetic properties of Gd-substituted Mn Zn ferrite nanoparticles as a potential low-TC agent for magnetic fluid hyperthermia  

Microsoft Academic Search

Gd-substituted Mn Zn ferrite nanoparticles of different compositions were synthesized by chemical co-precipitation method. To study the reduction of the Curie temperature (TC) for different samples, their magnetic properties in dependence from the composition and cationic distribution were investigated. An attempt to lower the TC of superparamagnetic particles to the optimal temperature required in magnetic fluid hyperthermia (44 47 °C)

Tatiana N. Brusentsova; Nikolay A. Brusentsov; Viatcheslav D. Kuznetsov; Vladimir N. Nikiforov

2005-01-01

236

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

237

Elastic properties of nanocrystalline aluminum substituted nickel ferrites prepared by co-precipitation method  

NASA Astrophysics Data System (ADS)

NiAlxFe2-xO4 (x = 0.0-1.0 in the step of 0.2) spinel ferrite system was prepared by the co-precipitation method. The elemental compositional stoichiometry, microstructure, infrared spectral and elastic properties have been carried out by means of energy dispersive analysis of X-ray (EDAX), scanning electron microscopy (SEM) and infrared spectroscopic (IR) measurements. Infrared spectra were carried out at room temperature in the wavenumber range of 300-800 cm-1. The IR spectra show three major absorption bands. High frequency bands '?1' is assigned to the tetrahedral and low frequency bands '?2' is assigned to the octahedral complex. Small frequency bands '?3' is assigned to Al3+O-2 complexes. Force constant for the tetrahedral and octahedral site was determined by using IR data. Force constant used to calculate the stiffness constants (C11 and C12). Using the values of stiffness constants; elastic moduli such as Young's modulus, bulk modulus, modulus of rigidity, Poisson ratio and Debye temperature were calculated.

Patange, S. M.; Shirsath, Sagar E.; Jadhav, S. P.; Hogade, V. S.; Kamble, S. R.; Jadhav, K. M.

2013-04-01

238

Preparation and Properties of Various Magnetic Nanoparticles  

PubMed Central

The fabrications of iron oxides nanoparticles using co-precipitation and gadolinium nanoparticles using water in oil microemulsion method are reported in this paper. Results of detailed phase analysis by XRD and Mössbauer spectroscopy are discussed. XRD analysis revealed that the crystallite size (mean coherence length) of iron oxides (mainly ?-Fe2O3) in the Fe2O3 sample was 30 nm, while in Fe2O3/SiO2 where the ?-Fe2O3 phase dominated it was only 14 nm. Gd/SiO2 nanoparticles were found to be completely amorphous, according to XRD. The samples showed various shapes of hysteresis loops and different coercivities. Differences in the saturation magnetization (MS) correspond to the chemical and phase composition of the sample materials. However, we observed that MS was not reached in the case of Fe2O3/SiO2, while for Gd/SiO2 sample the MS value was extremely low. Therefore we conclude that only unmodified Fe2O3 nanoparticles are suitable for intended biosensing application in vitro (e.g. detection of viral nucleic acids) and the phase purification of this sample for this purpose is not necessary. PMID:22574017

Drbohlavova, Jana; Hrdy, Radim; Adam, Vojtech; Kizek, Rene; Schneeweiss, Oldrich; Hubalek, Jaromir

2009-01-01

239

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.

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

2014-01-01

240

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

241

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

242

Gum ghatti-chitosan polyelectrolyte nanoparticles: preparation and characterization.  

PubMed

The objective of the present study was to optimize the interaction between gum ghatti and chitosan to prepare polyelectrolyte nanoparticles using ofloxacin as the model drug. The effect of varying the concentration of gum ghatti, chitosan, Pluronic F-127, and ofloxacin on particle size and entrapment efficiency was studied using central composite experimental design. The optimized calculated parameters were concentrations of gum ghatti (0.12% w/v), chitosan (0.22% w/v), Pluronic F-127 (0.05% w/v), ofloxacin (0.1% w/v), which provided polyelectrolyte nanoparticles of size 121.6 nm and 94.49% entrapment. On screening for antibacterial activity, it was observed that polyelectrolyte nanoparticles had antibacterial activity comparable to the aqueous solution. Further, it was observed that polyelectrolyte nanoparticles released the drug by diffusion through the matrix following Higuchi's square-root kinetics. PMID:23924761

Shelly; Ahuja, Munish; Kumar, Ashok

2013-10-01

243

Structure, morphology and magnetic properties of Mg(x) Zn(1 - x)Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni(x)Zn(1 - x)Fe2O4 ferrites  

Microsoft Academic Search

The synthesis and properties of Mg(x)Zn(1 - x)Fe2O4 spinel ferrites as a low-toxicity alternative to the technologically significant Ni(x)Zn(1 - x)Fe2O4 ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and

A. Daigle; J. Modest; A. L. Geiler; S. Gillette; Y. Chen; M. Geiler; B. Hu; S. Kim; K. Stopher; C. Vittoria; V. G. Harris

2011-01-01

244

A Comparative Study on the Structural and Magnetic Properties of Nickel Ferrite Nanoparticles Synthesized by Sol-gel and Coprecipitation Techniques  

Microsoft Academic Search

Nanomagnetic nickel ferrite particles were prepared by sol-gel and co-precipitation techniques. Synthesized samples were annealed at 400 °C and 600 °C for two hour to study the variation of properties with temperature. Structural characterization carried out using X-ray Diffraction Technique (XRD), confirmed the formation of polycrystalline single phase nickel ferrite particles in both the methods. Morphology and size of the

Binu P. Jacob; M. Suresh Babu; Sukhvir Singh; Krishan Lal; E. M. Mohammed

2010-01-01

245

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

246

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

247

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

248

Synthesis and investigation of magnetic properties of substituted ferrite nanoparticles of spinel system Mn1-xZnx[Fe2-yLy]O4  

Microsoft Academic Search

Superparamagnetic nanoparticles of the spinel ferrite four-element system Mn1-xZnx[Fe2-yLy]O4 (where L:Gd3+, La3+, Ce3+, Eu3+, Dy3+, Er3+,Yb3+) were synthesized by the co-precipitation method. The magnetic moments of the 10 nm diameter nanoparticles were comparable to the ones of Fe3O4 nanoparticles. A comparatively low TC (˜52 72 °C) was observed for some of the compositions. The heating mechanism of the superparamagnetic particles

Tatiana N. Brusentsova; Viatcheslav D. Kuznetsov

2007-01-01

249

Synthesis and investigation of magnetic properties of substituted ferrite nanoparticles of spinel system Mn 1? x Zn x [Fe 2? y L y ]O 4  

Microsoft Academic Search

Superparamagnetic nanoparticles of the spinel ferrite four-element system Mn1?xZnx[Fe2?yLy]O4 (where L:Gd3+, La3+, Ce3+, Eu3+, Dy3+, Er3+,Yb3+) were synthesized by the co-precipitation method. The magnetic moments of the 10nm diameter nanoparticles were comparable to the ones of Fe3O4 nanoparticles. A comparatively low TC (?52–72°C) was observed for some of the compositions. The heating mechanism of the superparamagnetic particles in the AC

Tatiana N. Brusentsova; Viatcheslav D. Kuznetsov

2007-01-01

250

Structure, morphology and magnetic properties of Mg(x) Zn(1 - x)Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni(x)Zn(1 - x)Fe2O4 ferrites  

NASA Astrophysics Data System (ADS)

The synthesis and properties of Mg(x)Zn(1 - x)Fe2O4 spinel ferrites as a low-toxicity alternative to the technologically significant Ni(x)Zn(1 - x)Fe2O4 ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg(x)Zn(1 - x)Fe2O4 were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ~ 80-120 nm) with an average diameter of the order of 100 nm ± 20 nm and could be produced in high process yields of up to 25 g l - 1. In contrast, particles synthesised by the polyol-based co-precipitation method possess a narrower size distribution with an average diameter in the 30 nm ± 5 nm range but are limited to smaller yields of ~ 6 g l - 1. Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties.

Daigle, A.; Modest, J.; Geiler, A. L.; Gillette, S.; Chen, Y.; Geiler, M.; Hu, B.; Kim, S.; Stopher, K.; Vittoria, C.; Harris, V. G.

2011-07-01

251

Anomalous magnetic antiresonance and resonance in ferrite nanoparticles embedded in opal matrix  

NASA Astrophysics Data System (ADS)

Observation of magnetic antiresonance phenomenon is reported in 3D opal nanocomposite with embedded ferrite particles. Antiresonance at microwave frequencies of millimeter waveband was observed. It results in a sharp maximum of the reflection coefficient of an electromagnetic wave. Measurements were carried out in the frequency range from 26 to 38 GHz for two compositions of embedded ferrite particles, namely, the Co0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4. The physical nature of antiresonance is discussed.

Ustinov, V. V.; Rinkevich, A. B.; Perov, D. V.; Samoilovich, M. I.; Klescheva, S. M.

2012-01-01

252

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

253

Comparative studies on the structure and electromagnetic properties of Ni?Zn ferrites prepared via co-precipitation and conventional ceramic processing routes  

Microsoft Academic Search

The magnetic and physical properties of ferrites are very sensitive to microstructure, which in turn critically depends on the manufacturing process. In this study, nickel zinc ferrite powder with composition Ni0.8Zn0.2Fe2O4 has been prepared via conventional ceramic processing and co-precipitation methods. The toroidal and pellet form samples were sintered at various temperatures such as 1100, 1200 and 1300°C. The microstructure,

Tania Jahanbin; Mansor Hashim; Khamirul Amin Mantori

2010-01-01

254

Microwave absorption properties of polymer composites with amorphous Fe-B and Ni-Zn-Co ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Nowadays, many communication devices use GHz-range microwaves, which cause serious issues, such as electromagnetic interference. For the prevention of these problems, microwave absorbers consisting of polymer composites with magnetic particles have received attention. With the current trend being to miniaturize devices, thin microwave absorber are now required. This paper reports that polymer composites with amorphous Fe-B submicrometer particles and Ni-Zn-Co ferrite nanoparticles showed a permeability of µ r ' = 8.0-9.0 at 1.0 GHz and a resonant frequency of f r = 1.8-2.4 GHz. They also exhibited good microwave absorption properties at 0.7-1.4 GHz for thicknesses of 2.5-3.9 mm.

Shimba, Kazuaki; Yuki, Shozo; Tezuka, Nobuki; Sugimoto, Satoshi

2013-06-01

255

Properties of Cr-substituted M-type barium ferrites prepared by nitrate citrate gel-autocombustion process  

NASA Astrophysics Data System (ADS)

The Cr-substituted M-type barium hexaferrites, BaFe 12-xCr xO 19, with x=0.0-0.8 have been successfully prepared by nitrate-citrate auto-combustion process using citric acid as a fuel/reductant and nitrates as oxidants. The resulting precursors were calcined at 1100 °C for 1 h and followed by sintering at 1200 °C for 12 h in oxygen atmosphere. The ferrites were systematically investigated by using powder X-ray diffractometer (XRD), magnetic hysteresis recorder, Mössbauer spectrometer, and scanning electron microscope (SEM). The XRD data show the formation of pure magnetoplumbite phase without any other impurity phases. Both a and c lattice parameters calculated by the Rietveld method systematically decrease with increasing Cr content. The effects of Cr 3+ ions on the barium ferrites were reported and discussed in detail. The site preference of Cr 3+ and magnetic properties of the ferrites have been studied using Mössbauer spectra and hystereses. The results show that the magnetic properties are closely related to the distributions of Cr 3+ ions on the five crystallographic sites. The saturation magnetization systematically decreases, however, the coercivity increases with Cr concentration. The magnetization and Mössbauer results indicate that the Cr 3+ ions preferentially occupy the 2a, 12k, and 4f VI sites. The average size of hexagonal platelets obtained by SEM photographs tends to decrease with respect to Cr content.

Ounnunkad, S.; Winotai, P.

2006-06-01

256

Preparation of DNA/Gold Nanoparticle Encapsulated in Calcium Phosphate.  

PubMed

Biocompatible DNA/gold nanoparticle complex with a protective calcium phosphate (CaP) coating was prepared by incubating DNA/gold nanoparticle complex coated by hyaluronic acid in SBF (simulated body fluid) with a Ca concentration above 2?mM. The CaP-coated DNA complex was revealed to have high compatibility with cells and resistance against enzymatic degradation. By immersion in acetate buffer (pH 4.5), the CaP capsule released the contained DNA complex. This CaP capsule including a DNA complex is promising as a sustained-release system of DNA complexes for gene therapy. PMID:21773047

Ito, Tomoko; Ibe, Koyuki; Uchino, Tomohiro; Ohshima, Hiroyuki; Otsuka, Makoto

2011-01-01

257

Preparation of Iron Oxide-Entrapped Chitosan Nanoparticles for Stem Cell Labeling  

Microsoft Academic Search

This study intended to prepare iron oxide nanoparticle-entrapped chitosan (CS) nanoparticles for stem cell labeling. The nanoparticles were synthesized by polymerizing iron oxide nanoparticle-associated methacrylic acid monomer in the presence of CS. TEM revealed that the well-defined iron oxide nanoparticles were successfully encapsulated inside the CS nanoparticles. The effect of CS at different [NH2]\\/[COOH] molar ratios on particle size, surface

Saowaluk Chaleawlert-umpon; Varissaporn Mayen; Krissanapong Manotham; Nuttaporn Pimpha

2010-01-01

258

Preparation of nanocrystalline Fe 3-x LaxO4 ferrite and their adsorption capability for Congo red.  

PubMed

This investigation was to increase the adsorption capacity of magnetite for Congo red (CR) by adulterating a small quantity of La(3+) ions into it. The adsorption capability of nanocrystalline Fe(3-x)La(x)O(4) (x=0, 0.01, 0.05, 0.10) ferrite to remove CR from aqueous solution was evaluated carefully. Compared with undoped magnetite, the adsorption values were increased from 37.4 to 79.1 mg g(-1). The experimental results prove that it is effectual to increase the adsorption capacity of magnetite by doped La(3+) ions. Among the La(3+)-doped magnetite, Fe(2.95)La(0.05)O(4) nanoparticles exhibit the highest saturation magnetization and the maximum adsorption capability. The desorption ability of La(3+)-doped magnetite nanoparticles loaded by CR can reach 92% after the treatment of acetone. Furthermore, the Fe(3-x)La(x)O(4) nanoparticles exhibited a clearly ferromagnetic behavior under applied magnetic field, which allowed their high-efficient magnetic separation from wastewater. It is found that high magnetism facilitates to improve their adsorption capacity for the similar products. PMID:21944701

Wang, Lixia; Li, Jianchen; Wang, Yingqi; Zhao, Lijun

2011-11-30

259

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

PubMed Central

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; Šuštar, Vid; Verani?, Peter; Pavlin, Mojca

2013-01-01

260

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

261

Structural and magnetic properties of zinc- and aluminum-substituted cobalt ferrite prepared by co-precipitation method  

Microsoft Academic Search

Spinal ferrites having the general formula Co1 ? x\\u000a Zn\\u000a x\\u000a Fe2 ? x\\u000a Al\\u000a x\\u000a O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were prepared using the wet chemical co-operation technique. The samples were annealed\\u000a at 800°C for 12 h and were studied by means of X-ray diffraction, magnetization and low field AC susceptibility measurements.\\u000a The X-ray

S. T. Alone; K. M. Jadhav

2008-01-01

262

Structural and magnetic properties of zinc- and aluminum-substituted cobalt ferrite prepared by co-precipitation method  

Microsoft Academic Search

Spinal ferrites having the general formula Co_{1-x}Zn_xFe_{2-x}Al_xO_4 (x=0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) were prepared using the wet chemical co-operation technique. The samples were annealed at 800°C for 12 h and were studied by means of X-ray diffraction, magnetization and low field AC susceptibility measurements. The X-ray analysis showed that all the samples had single-phase cubic spinel structure. The

S. T. Alone; K. M. Jadhav

2008-01-01

263

Comparison of the Sol-gel Method with the Coprecipitation Technique for Preparation of Hexagonal Barium Ferrite  

Microsoft Academic Search

Hexagonal barium ferrite BaFe12O19 particles were prepared by sol-gel and coprecipitation methods, respectively. The composition of the so-obtained materials was investigated by means of XRD. By the sol-gel method, non-anticipated intermediate crystalline phases, such as ?-Fe2O3, ?-Fe2O3, BaCO3, and BaFe2O4etc., were formed with the delay of the formation of BaFe12O19. The formation of single phase BaFe12O19 required calcination at 850

Jing-ping WANG; Ying LIU; Mi-lin ZHANG; Ying-jie QIAO; Tian XIA

2008-01-01

264

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

265

A novel method of preparing transition metal nanoparticles.  

PubMed

The hydrolysis behaviour of some Mg-rich compounds (Mg2Ni, Mg2Cu, Mg54Ag17 and Mg3Au) at room temperature has been systematically investigated. Ni, Cu, Ag and Au nanoparticles have successfully been prepared by the hydrolysis of these compounds. The Ni, Cu, Ag, and Au nanoparticles obtained by the hydrolysis method are close to spherical in shape with a particle size below 20 nm. A continuous skeleton of magnesium atoms could be the channel for the dissolution of Mg atoms in these Mg-rich compounds, which is helpful in the hydrolysis of these Mg-rich compounds. The hydrolysis of the Mg-rich compounds provides a new and relatively simple method for the production of transition metal nanoparticles. PMID:19441544

Wang, Huabin; Northwood, Derek O

2009-02-01

266

Preparation of griseofulvin nanoparticles from water-dilutable microemulsions.  

PubMed

Nanoparticles of griseofulvin, a model drug with poor solubility and low bioavailability, were prepared from water dilutable microemulsions by the solvent diffusion technique. Solvent-in-water microemulsion formulations containing water, butyl lactate, lecithin, taurodeoxycholate sodium salt (TDC) or dipotassium glycyrrhizinate (KG), 1,2-propanediol or ethanol were used. The formation of macroscopically homogeneous, stable, fluid, optically transparent, isotropic solutions (microemulsions) was investigated by constructing pseudo-ternary phase diagrams. In the presence of TDC or KG, microemulsion systems that remained transparent on water dilution could be obtained. The displacement of butyl lactate, with an excess of water, from the internal phase of the microemulsions containing the drug into the external phase, lead to successful fabrication of drug nanosuspensions. Nanoparticle size was dependent on microemulsion composition: using KG, griseofulvin nanoparticles below 100 nm with low polydispersity and an increased dissolution rate were obtained. PMID:12623199

Trotta, Michele; Gallarate, Marina; Carlotti, Maria Eugenia; Morel, Silvia

2003-03-26

267

Enhancement of electrical properties due to Cr3+ substitution in Co-ferrite nanoparticles synthesized by two chemical techniques  

NASA Astrophysics Data System (ADS)

Nanocrystalline cobalt ferrites with nominal composition CoCrxFe2-xO4 ranging from x=0.0 to 0.5 with step increment of 0.25 were prepared by sol-gel auto combustion and chemical co-precipitation techniques. A comparative study of structural, electrical and magnetic properties of these ferrites has been measured using different characterization techniques. Structural and micro-structural studies were measured using X-ray diffraction, Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy and atomic force microscopy. Crystallite sizes of the series are within the range of 12-29±2 nm. Lattice parameters decrease by increasing Cr3+ concentration. FTIR confirms the presence of two lattice absorption bands. DC electrical resistivity increases to a value of ˜1010 ?-cm with increase in Cr3+ concentration, but the most significant increase is in samples prepared by sol-gel combustion. Dielectric properties have been measured as a function of frequency at room temperature. Dielectric loss decreases to 0.1037 and 0.0108 at 5 MHz for chemical co-precipitation and sol-gel combustion, respectively. Impedance measurements further helped in analyzing the electrical properties and to separate the grain and grain boundary resistance effects using a complex impedance analysis. Magnetic parameters were studied using a vibrating sample magnetometer in the applied field of 10 kOe. The saturation magnetization decreased from 63 to 10.8 emu/gm with increase in Cr3+ concentration.

Pervaiz, Erum; Gul, I. H.

2012-11-01

268

Frequency dependent dielectric measurements of Cd2+ doped Mn-Zn nano ferrites prepared by sol gel and coprecipitation methods  

NASA Astrophysics Data System (ADS)

Ferrite powders of Mn-Zn doped with Cd2+ (Mn0.5CdxZn0.5-xFe2O4) were prepared by the sol gel auto- combustion and coprecipitation methods. The effect of Cd2+ doping on the crystalline phase formation was investigated by X-ray diffraction which confirms the spinel structure of prepared samples. Crystallite size found to be lower for samples prepared by coprecipitation method. The samples prepared using coprecipitation, found to be denser as compared to sol gel method. SEM analysis confirmed the nano structure of the prepared samples. Dielectric properties were studied using impedance analyzer (20 Hz - 5 MHz) and RF material analyzer (1 MHz - 3 GHz) respectively. DC electrical measurements showed highly resistive nature of the prepared samples and values are high for samples prepared from sol gel method. Impedance spectroscopic analysis was carried out in the frequency range from 20 Hz to 5 MHz for the prepared samples, showing resistance of grain boundary is higher than grains. Impedance plane plots gave information about the resistive and reactive parts of impedance. The presence of semicircular arcs at lower frequency side, confirms that the high resistance of samples is due to increase in the number of grain boundaries in the nano synthesised samples.

Humaira, A.; Asghari, M.

2013-06-01

269

Adsorption of bovin serum albumin (BSA) onto the magnetic chitosan nanoparticles prepared by a microemulsion system  

Microsoft Academic Search

The adsorption characteristics of BSA onto the magnetic chitosan nanoparticles have been investigated in this paper. The magnetic chitosan nanoparticles were prepared by adding the basic precipitant of NaOH solution into a W\\/O microemulsion system. The morphology of magnetic chitosan nanoparticles was observed by transmission electron microscope (TEM). It was found that the diameter of magnetic chitosan nanoparticles was from

Yujun Wang; Xianghua Wang; Guangsheng Luo; Youyuan Dai

2008-01-01

270

Effect of Cadmium Substitution on Structural and Magnetic Properties of Nano Sized Nickel Ferrite  

NASA Astrophysics Data System (ADS)

The structure and crystal phase of the nanocrystalline powders of Ni1-xCdxFe2O4 (0<=x<=0.5) mixed ferrite, synthesized by wet chemical co-precipitation method, were characterized by X-ray diffraction. Results showed that the lattice parameter increased with increasing Cd concentration. Microstructure was studied by scanning electron microscopy. TG/DTA studies were carried out on co-precipitated sulphate complexes. These studies revealed the low ferritization temperature (650 °C) of the ferrite system synthesized by presently adopted route of synthesis and occurrence of simultaneous decomposition and ferritization processes. Further studies by infrared spectroscopy were also conducted. Moreover, magnetic properties of the prepared nanoparticles were studied by magnetization and a.c. susceptibility measurements. The response of prepared Ni1-xCdxFe2O4 mixed ferrites to magnetic field was investigated. Results show that, magnetic susceptibility, Curie temperature, and effective magnetic moment decreased as the Cd content increases.

Pralhadrao Jadhav, Sanjay; Ghanshamji Toksha, Bhagwan; Marutirao Jadhav, Kamalakar; Dadarao Shinde, Narayan

2010-08-01

271

Structural and magnetic properties of Ni1-xZnxFe2O4 nano-crystalline ferrites prepared via novel chitosan method  

NASA Astrophysics Data System (ADS)

In the present study, nano-crystalline Ni1-xZnxFe2O4 ferrites (x = 0.0-1.0) were prepared via novel chitosan method. The prepared ferrites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM) techniques. XRD revealed the formation of spinel single-phase structure for the samples with Zn-content more than 0.4. The crystallite sizes estimated using Scherer formula are in the range 34-45 nm. TEM images reflect the agglomeration characteristics of the prepared ferrites. FT-IR spectra show two prominent characteristic peaks of ferrites. VSM measurement suggests the validity of the entire method for preparation of ferrites with high magnetization. The saturation magnetization was found to increase up to x = 0.4 then gradually decrease while coercivity decreased with increasing Zn-content. These changes in the magnetic properties by the addition of Zn were discussed depending on the estimated cation distribution of the system and the magneto-crystalline anisotropy of the entire ions, respectively.

Gabal, M. A.; Kosa, S.; Al Mutairi, T. S.

2014-04-01

272

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

273

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

274

Structure and magnetic properties of chemically prepared mixtures of crystalline and amorphous Fe(B) nanoparticles  

Microsoft Academic Search

A fine dispersion of crystalline and amorphous Fe(B) nanoparticles has been chemically prepared and its structural and magnetic properties compared to those of the corresponding single phase nanoparticles. The coercivity of the as-prepared dispersion was intermediate between that of the single phase crystalline and amorphous nanoparticles but less than expected from a simple rule of mixtures. Moreover, after annealing at

A. Gorea; T. F. Ekiert; E. A. Pearson; K. M. Unruh

2005-01-01

275

Synthesis and investigation of magnetic properties of Gd-substituted Mn-Zn ferrite nanoparticles as a potential low- TC agent for magnetic fluid hyperthermia  

NASA Astrophysics Data System (ADS)

Gd-substituted Mn-Zn ferrite nanoparticles of different compositions were synthesized by chemical co-precipitation method. To study the reduction of the Curie temperature ( TC) for different samples, their magnetic properties in dependence from the composition and cationic distribution were investigated. An attempt to lower the TC of superparamagnetic particles to the optimal temperature required in magnetic fluid hyperthermia (44-47 °C) was made.

Brusentsova, Tatiana N.; Brusentsov, Nikolay A.; Kuznetsov, Viatcheslav D.; Nikiforov, Vladimir N.

2005-05-01

276

Synthesis and investigation of magnetic properties of Gd-substituted Mn–Zn ferrite nanoparticles as a potential low- T C agent for magnetic fluid hyperthermia  

Microsoft Academic Search

Gd-substituted Mn–Zn ferrite nanoparticles of different compositions were synthesized by chemical co-precipitation method. To study the reduction of the Curie temperature (TC) for different samples, their magnetic properties in dependence from the composition and cationic distribution were investigated. An attempt to lower the TC of superparamagnetic particles to the optimal temperature required in magnetic fluid hyperthermia (44–47°C) was made.

Tatiana N. Brusentsova; Nikolay A. Brusentsov; Viatcheslav D. Kuznetsov; Vladimir N. Nikiforov

2005-01-01

277

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

278

Preparation of Fe 3O 4–chitosan nanoparticles used for hyperthermia  

Microsoft Academic Search

The Fe3O4–chitosan nanoparticles with core-shell structure have been prepared by crosslinking method. Oleic acid modified Fe3O4 nanoparticles were firstly prepared by co-precipitation then chitosan was added to coat on the surface of the Fe3O4 nanoparticles by physical absorption. The Fe3O4–chitosan nanoparticles were obtained by crosslinking the amino groups on the chitosan using glutaraldehyde. Transmission electron microscopy showed that the Fe3O4–chitosan

Jingmiao Qu; Guang Liu; Yiming Wang; Ruoyu Hong

2010-01-01

279

Preparation of PLA and PLGA nanoparticles by binary organic solvent diffusion method  

Microsoft Academic Search

The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the binary organic solvent diffusion\\u000a method. The yield, particle size and size distribution of these nanoparticles were evaluated. The yield of nanoparticles prepared\\u000a by this method is over 90%, and the average size of the nanoparticles is between 130–180 nm. In order to clarify the effect\\u000a of the organic

Xin-yu Jiang; Chun-shan Zhou; Ke-wen Tang

2003-01-01

280

Novel metallic iron\\/manganese–zinc ferrite nanocomposites prepared by microwave hydrothermal flash synthesis  

Microsoft Academic Search

Metallic iron (?-Fe)\\/manganese–zinc ferrite (Fe3?x?yMnxZnyO4) nanocomposites have been successfully synthesized for the first time using microwave hydrothermal treatment of alcoholic solutions of chloride precursors and sodium ethoxide. This new type of nanocomposites, never obtained by conventional synthesis, can now be produced in a short period (e.g. 15s). The powders were characterized by X-ray diffraction, transmission electron microscopy and magnetic properties

T. Caillot; G. Pourroy; D. Stuerga

2011-01-01

281

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

282

Magnetic properties and superparamagnetism of co-substituted Ni–Zn ferrite nanoparticles  

Microsoft Academic Search

Mixed-ferrite (Ni0.6?xCox)Zn0.4Fe2O4 (x = 0–0.6) particles were synthesized by a co-precipitation method. X-Ray powder diffraction confirms their cubic spinel\\u000a structure. TEM micrographs and XRD calculations showed that the particle size d in the range of 9–29 nm. Magnetic measurements\\u000a reveal superparamagnetic behaviors, with a maximum blocking temperature TB and a relatively high saturation magnetization at x ? 0.2, corresponding to the maximum particle size. Effective

M. M. Eltabey

283

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

284

Formation of nanostructured magnetic films using layer-by-layer self-assembly of star polymers and magnetic nanoparticles.  

E-print Network

?? In this work, multi-layered thin film materials comprised of cobalt ferrite (CoFe2O4) magnetic nanoparticles and polystyrene amine-functionalized (PS-NH2) star polymers have been prepared on… (more)

Shah, Shimul

2011-01-01

285

Bioinspired preparation of alginate nanoparticles using microbubble bursting.  

PubMed

Nanoparticles are considered to be one of the most advanced tools for drug delivery applications. In this research, alginate (a model hydrophilic polymer) nanoparticles 80 to 200nm in diameter were obtained using microbubble bursting. The natural process of bubble bursting occurs through a number of stages, which consequently produce nano- and microsized droplets via two main production mechanisms, bubble shell disintegration and a jetting process. In this study, nano-sized droplets/particles were obtained by promoting the disintegrating mechanism and suppressing (limiting) the formation of larger microparticles resulting from the jetting mechanism. A T-junction microfluidic device was used to prepare alginate microbubbles with different sizes in a well-controlled manner. The size of the bubbles was varied by controlling two processing parameters, the solution flow rate and the bubbling pressure. Crucially, the bubble size was found to be the determining factor for inducing (or limiting) the bubble shell disintegration mechanism and the size needed to promote this process was influenced by the properties of the solution used for preparing the bubbles, particularly the viscosity. The size of alginate nanoparticles produced via the disintegration mechanism was found to be directly proportional to the viscosity of the alginate solution. PMID:25491969

Elsayed, Mohamed; Huang, Jie; Edirisinghe, Mohan

2015-01-01

286

Nanoparticle preparation of Mefenamic acid by electrospray drying  

SciTech Connect

Nanoparticles preparation of Mefenamic acid (MA) by using an electrospray drying method was conducted in this study. Electrospray drying is a process that uses electrostatic force to disperse a conductive liquid stream into fine charged droplets through the coulomb fission of charges in the liquid and finally dry into fine particles. Electrospray drying modes operation usually in Taylor cone jet, and it was formed by controlling applied voltage and liquid flow rate. A conductive liquid (2.77–8.55?Scm{sup ?1}) which is MA solution was prepared by using acetone with concentration 0.041 and 0.055 M before pumping at a flow rate of 3–6ml/h. By applying the applied voltage at 1.3–1.5 kV, Taylor cone jet mode was formed prior to the electrospray. During electrospray drying process, solvent evaporation from the droplet was occurring that leads to coulomb disruption and may generate to nanoparticles. The dried nanoparticles were collected on a grounded substrate that was placed at varying distance from the electrospray. MA particle with size range of 100–400 nm were produced by electrospray drying process. Characterization of particles by using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) show that particles formed into polymorph I.

Zolkepali, Nurul Karimah, E-mail: fitrah@salam.uitm.edu.my; Bakar, Noor Fitrah Abu, E-mail: fitrah@salam.uitm.edu.my; Anuar, Nornizar [Faculty Of Chemical Engineering, Universiti Teknologi Mara (UiTM), 40450 Shah Alam, Selangor (Malaysia); Naim, M. Nazli [Food and Process Department, Faculty of Engineering, Universiti Putra Malaysia (UPM), 43400 UPM Serdang, Selangor (Malaysia); Bakar, Mohd Rushdi Abu [Kulliyyah of Pharmacy, International Islamic University Malaysia, P.O Box 141, 25710, Kuantan, Pahang (Malaysia)

2014-02-24

287

Characterization of binary gold/platinum nanoparticles prepared by sonochemistry technique  

NASA Astrophysics Data System (ADS)

Aqueous solutions with Au 3+and Pt 4+ ions and additives of surfactants (SDS or PEG-MS) were irradiated with an ultrasound at 200 kHz with an input power of 4.2 W/cm 2, and colloidal nanoparticles were prepared. The prepared nanoparticles were characterized by XRD, TEM, HRTEM, EDX and 197Au Mössbauer spectroscopy. It was found that the structures of nanoparticles were changed with the surfactants; Au and Pt nanoparticles were prepared individually by using SDS, and bimetallic Au/Pt alloy nanoparticles with a core-shell structure were produced in the presence of PEG-MS.

Nakanishi, M.; Takatani, H.; Kobayashi, Y.; Hori, F.; Taniguchi, R.; Iwase, A.; Oshima, R.

2005-02-01

288

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

NASA Astrophysics Data System (ADS)

This study deals with the exploration of NixCo1-xFe2O4 (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 Co0.4Ni0.6Fe2O4 (154.02 m2 g-1). Co0.4Ni0.6Fe2O4 showed the best catalytic activity for reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 as reducing agent, whereas CoFe2O4 was found to be catalytically inactive. The reduction reaction followed pseudo-first order kinetics. The effect of varying the concentration of catalyst and NaBH4 on the reaction rates was also scrutinized. The photo-oxidative degradation of Rhodamine B, enhanced oxidation efficacy was observed with the introduction of Ni2+ in to the cobalt ferrite lattice due to octahedral site preference of Ni2+. Almost 99% degradation was achieved in 20 min using NiFe2O4 nanoparticles as catalyst.

Singh, Charanjit; Goyal, Ankita; Singhal, Sonal

2014-06-01

289

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

290

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

291

Biocompatibility of various ferrite nanoparticles evaluated by in vitro cytotoxicity assays using HeLa cells  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles for thermotherapy must be biocompatible and possess high thermal efficiency as heating elements. The biocompatibility of Fe 3O 4 (20-30 nm), ZnFe 2O 4 (15-30 nm) and NiFe 2O 4 (20-30 nm) nanoparticles was studied using a cytotoxicity colony formation assay and a cell viability assay. The Fe 3O 4 sample was found to be biocompatible on HeLa cells. While ZnFe 2O 4 and NiFe 2O 4 were non-toxic at low concentrations, HeLa cells exhibited cytotoxic effects when exposed to concentrations of 100 ?g/ml nanoparticles.

Tomitaka, Asahi; Hirukawa, Atsuo; Yamada, Tsutomu; Morishita, Shin; Takemura, Yasushi

2009-05-01

292

A comparative study of structural, electrical and magnetic properties of magnesium ferrite nanoparticles synthesised by sol-gel and co-precipitation techniques  

Microsoft Academic Search

Nano-sized magnesium ferrite was synthesised using co-precipitation and sol-gel techniques. Structural characterisation was performed using X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectrometer and scanning electron microscope. XRD analysis reveals the prepared samples are single phasic without any impurity. Particle size calculation shows that the crystallite size of sol-gel prepared samples is 9?nm and co-precipitation sample is 11?nm. FTIR analysis

Smitha Thankachan; Sheena Xavier; Binu Jacob; E. M. Mohammed

2012-01-01

293

Effect of Dy+3 on the structure and static magnetic properties of spin-glass MnZn ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Structural and static magnetic properties of a series of ferrites nanoparticles (the size ranges from 7.6 to 13.5 nm) having nominal chemical composition DyxMn0.5Zn0.5Fe2-xO4 (x = 0, 0.02, 0.04, 0.06) have been investigated. The x-ray diffraction analysis clarifies that the samples crystallize in typical cubic spinel structure. Incorporation of Dy ions in the Mn0.5Zn0.5Fe2O4 lattice structure has been proved by Raman spectroscopy measurements. Correspondingly, a significant increase in the grain size and a dramatic change in the magnetic properties are observed. The magnetization versus magnetic field M(H) plots are nonhysteretic where the coercivity remains zero and display Langevin-like behavior. The temperature dependence of magnetization M(T) plots in field cooling regime shows spin-glass behavior indicating a strong interaction between the magnetic moments. The blocking temperature determined from M(T) plots in zero field cooling regime increases as the Dy content increases.

Ibrahim, E. M. M.

2013-04-01

294

Ultrasonic Cavitation induced Water in Vegetable oil emulsion droplets - A Simple and Easy Technique to Synthesize Manganese Zinc Ferrite Nanocrystals with improved magnetisation  

Microsoft Academic Search

In the present investigation, synthesis of manganese zinc ferrite (Mn0.5Zn0.5Fe2O4) nanoparticles with narrow size distribution have been prepared using ultrasound assisted emulsion (consisting of rapeseed oil as an oil phase and aqueous solution of Mn+2, Zn+2 and Fe+2 acetates) and evaporation processes. The as-prepared ferrite was nanocrystalline. In order to remove the small amount of oil present on the surface

Manickam Sivakumar; Atsuya Towata; Kyuichi Yasui; Toru Tuziuti; Teruyuki. Kozuka; Yasuo Iida; Michail M. Maiorov; Elmars Blums; Dipten Bhattacharya; Neelagesi Sivakumar; Ashok M

295

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

296

Field dependent transition to the non-linear regime in magnetic hyperthermia experiments: Comparison between maghemite, copper, zinc, nickel and cobalt ferrite nanoparticles of similar sizes  

NASA Astrophysics Data System (ADS)

Further advances in magnetic hyperthermia might be limited by biological constraints, such as using sufficiently low frequencies and low field amplitudes to inhibit harmful eddy currents inside the patient's body. These incite the need to optimize the heating efficiency of the nanoparticles, referred to as the specific absorption rate (SAR). Among the several properties currently under research, one of particular importance is the transition from the linear to the non-linear regime that takes place as the field amplitude is increased, an aspect where the magnetic anisotropy is expected to play a fundamental role. In this paper we investigate the heating properties of cobalt ferrite and maghemite nanoparticles under the influence of a 500 kHz sinusoidal magnetic field with varying amplitude, up to 134 Oe. The particles were characterized by TEM, XRD, FMR and VSM, from which most relevant morphological, structural and magnetic properties were inferred. Both materials have similar size distributions and saturation magnetization, but strikingly different magnetic anisotropies. From magnetic hyperthermia experiments we found that, while at low fields maghemite is the best nanomaterial for hyperthermia applications, above a critical field, close to the transition from the linear to the non-linear regime, cobalt ferrite becomes more efficient. The results were also analyzed with respect to the energy conversion efficiency and compared with dynamic hysteresis simulations. Additional analysis with nickel, zinc and copper-ferrite nanoparticles of similar sizes confirmed the importance of the magnetic anisotropy and the damping factor. Further, the analysis of the characterization parameters suggested core-shell nanostructures, probably due to a surface passivation process during the nanoparticle synthesis. Finally, we discussed the effect of particle-particle interactions and its consequences, in particular regarding discrepancies between estimated parameters and expected theoretical predictions.

Verde, E. L.; Landi, G. T.; Carrião, M. S.; Drummond, A. L.; Gomes, J. A.; Vieira, E. D.; Sousa, M. H.; Bakuzis, A. F.

2012-09-01

297

Structural and magnetic properties of dispersed nickel ferrite nanoparticles synthesized through thermal decomposition route  

NASA Astrophysics Data System (ADS)

Dispersed NiFe2O4 nanoparticles are synthesized through thermal decomposition of mixed-metal (Ni2+Fe3+)-oleate complex in the presence of high boiling point organic solvent 1-octadecene with oleic acid, by tuning the mixed-metal (Ni2+Fe3+)-oleate complex precursor and the temperature. Oleic acid is used as a surfactant, capped on the surface of the particles, which assists the particles to disperse in hexane. The as-synthesized NiFe2O4 nanoparticles have a cubic spinel structure as characterized by x-ray diffraction. The ferrimagnetic nature of these nanoparticles is conformed from the field dependent room temperature magnetization curves measured using vibrating sample magnetometer. The saturation magnetization of these nanoparticles strongly depends on the particle size which can be tuned by the mixed-metal (Ni2+Fe3+)-oleate complex precursor concentration and the synthesis temperature. Transmission electron microscope images show that the particles are nearly monodispersed at high synthesis temperature.

Behera, Bhaskar Chandra; Venkata, Ravindra A.; Srivastava, Chandan; Padhan, Prahallad

2013-02-01

298

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

299

Magnetic memory effects in nickel ferrite/polymer nanocomposites  

NASA Astrophysics Data System (ADS)

Memory effects are reported in the field cooled (FC) magnetization of pure nickel ferrite powders and nickel ferrite nanocomposites prepared by the solution casting method. Studies carried out at different concentrations of the nanocomposite indicate that memory effects are suppressed with increasing concentration of the magnetic component in the nanocomposite. This is linked to the increase in the dipolar interaction strength in the nanocomposites, which increase with increasing concentration, as confirmed by the Henkel plots. Model simulations of the FC magnetization carried out on an interacting array of monodispersed magnetic nanoparticles indicate that growing cluster sizes inhibit memory effects.

Malik, Rakesh; Sehdev, Neeru; Lamba, Subhalakshmi; Sharma, Parmanand; Makino, Akihiro; Annapoorni, Subramanian

2014-03-01

300

Cadmium ferrite ionic magnetic fluid: Magnetic resonance investigation  

Microsoft Academic Search

In contrast to all magnetic resonance investigations previously performed using magnetic fluids (MFs) based on spinel ferrite nanoparticles, cadmium-ferrite-based MFs present an intense, relatively sharp resonance line near g=4, in addition to the typical, broad structure near g=2. The broad resonance structure is associated with larger cadmium-ferrite nanoparticles, whereas the sharp resonance line is associated with ultrasmall cadmium-ferrite nanoparticles. Transmission

O. Silva; E. C. D. Lima; P. C. Morais

2003-01-01

301

Cadmium ferrite ionic magnetic fluid: Magnetic resonance investigation  

Microsoft Academic Search

In contrast to all magnetic resonance investigations previously performed using magnetic fluids (MFs) based on spinel ferrite nanoparticles, cadmium–ferrite-based MFs present an intense, relatively sharp resonance line near g=4, in addition to the typical, broad structure near g=2. The broad resonance structure is associated with larger cadmium–ferrite nanoparticles, whereas the sharp resonance line is associated with ultrasmall cadmium–ferrite nanoparticles. Transmission

O. Silva; E. C. D. Lima; P. C. Morais

2003-01-01

302

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

303

Albumin nanoparticles for the delivery of gabapentin: preparation, characterization and pharmacodynamic studies.  

PubMed

The study was aimed to prepare and evaluate gabapentin loaded albumin nanoparticles and to find out their effectiveness in treating epilepsy. Albumin nanoparticles of gabapentin were prepared by pH-coacervation method. The drug was administered into animals as free drug, gabapentin bound with nanoparticles, and gabapentin bound with nanoparticles coated with polysorbate 80. The polysorbate 80 coated nanoparticles increased the gabapentin concentration in the brain about 3 fold in comparison with the free drug. Moreover, the polysorbate 80 coated nanoparticles significantly reduced the duration of all phases of convulsion in both maximal electroshock induced and pentylenetetrazole induced convulsion models in comparison with free drug and drug bound with nanoparticle formulations, which indicates the ability of polysorbate 80 coated nanoparticles to enhance the gabapentin concentration in the brain. PMID:24999053

Wilson, Barnabas; Lavanya, Y; Priyadarshini, S R B; Ramasamy, Muthu; Jenita, Josephine Leno

2014-10-01

304

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

305

Preparation and characterization of carboxyl functionalization of chitosan derivative magnetic nanoparticles  

Microsoft Academic Search

The functionalized magnetic Fe3O4-chitosan derivative nanoparticles have been prepared by the covalent binding of alpha-ketoglutaric acid chitosan (KCTS) onto the surface of Fe3O4 magnetic nanoparticles via carbodiimide activation. Transmission electron microscopy (TEM) showed that the KCTS-bound Fe3O4 nanoparticles were regular spheres with a mean diameter of 26nm. X-ray diffraction (XRD) patterns indicated that the Fe3O4 nanoparticles were pure Fe3O4 with

Gui-yin Li; Ke-long Huang; Yu-ren Jiang; Ping Ding; Dong-liang Yang

2008-01-01

306

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

307

Preparation and characterization of barium hexagonal ferrite thin films on a Pt template  

NASA Astrophysics Data System (ADS)

M-type barium hexagonal ferrite films with the crystallographic c axis out of plane were successfully deposited onto a Pt template using a metallo-organic decomposition technique. For the best film, x-ray diffraction patterns revealed strong (00l) reflections and a texture fraction of 0.953, confirming the out of plane c axis orientation. Atomic force microscopy images confirm hexagonal grains in this film with an average lateral size of ˜500 nm. Hysteresis loops revealed a high effective out of plane anisotropy field, high perpendicular remanent magnetization Mr=0.93 Ms, and out of plane coercivity of 4.5 kOe. Out of plane Ferromagnetic Resonance measurements determined the values of ? =2.79 GHz/kOe and effective anisotropy field. The full width at half maximum FMR linewidth was 338 Oe at 60 GHz. These properties are suitable for possible use in on-wafer millimeter wave devices.

Nie, Yan; Harward, I.; Balin, K.; Beaubien, A.; Celinski, Z.

2010-04-01

308

Electrochemical and Structural Characterizations of InSb Nanoparticles Prepared Using a Sodium Naphthalenide  

E-print Network

Electrochemical and Structural Characterizations of InSb Nanoparticles Prepared Using a Sodium, Ansan, 426-791, South Korea InSb nanoparticles with a mean particle size of 10 nm prepared and TEM results revealed the progressive formation of extruded In from InSb, followed by the formation

Cho, Jaephil

309

Preparation and characterization of magnetic carboxymethyl chitosan\\/Fe3O4 composite nanoparticles  

Microsoft Academic Search

Monodisperse carboxymethyl chitosan-bound Fe3O4 magnetic nanoparticles can be potentially used as drug delivery carrier and a novel magnetic nano-adsorbent for the removal of pollutants from aqueous solutions. In this paper, the magnetic chitosan nanoparticles of about 20 nm were prepared by the carboxymethylation of chitosan and the followed binding on the surface of Fe3O4 nanoparticles which were prepared using a

Li-Min Zhou; Yi-Ping Wang; Qun-Wu Huang; Zhi-Rong Liue

2008-01-01

310

Preparation of gold nanoparticles\\/graphene hybrid using 4-mercaptobenzoyl functionalized graphene nanosheets as templates  

Microsoft Academic Search

We report an effective and simple route to prepare gold nanoparticles\\/graphene hybrid via the way of chemical functionalization. First, graphene nanosheets were functionalized with 4-mercaptobenzonic acid via a direct Friedel-Crafts acylation reaction in a polyphosphoric acid\\/phosphorus pentoxide medium. Second, gold nanoparticles were prepared from the in situ reduction of gold (III) chloride trihydrate by sodium borohydride. Subsequently, gold nanoparticles were

Tuan Anh Pham; Jong Su Kim; Don Kim; Yeon Tae Jeong

2012-01-01

311

Formation and cation distribution in supported manganese ferrite nanoparticles: an X-ray absorption study.  

PubMed

Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) techniques at both Fe and Mn K-edges were used to investigate the formation of MnFe(2)O(4) nanoparticles embedded in a silica aerogel matrix as a function of calcination temperature (at 450, 750 and 900 degrees C). Up to 450 degrees C, two separated highly-disordered phases of iron and manganese are present. With increasing the temperature (to 750 and 900 degrees C), the structure of aerogel nanoparticles becomes progressively similar to that of the spinel structure MnFe(2)O(4) (jacobsite). Quantitative determination of cations distribution in the spinel structure shows that aerogels calcined at 750 and 900 degrees C have a degree of inversion i = 0.20. A pure jacobsite sample synthesised by co-precipitation and used as a reference compound shows a much higher degree of inversion (i = 0.70). The different distribution of iron and manganese cations in the octahedral and tetrahedral sites in pure jacobsite and in the aerogels can be ascribed to partial oxidation of Mn(2+) to Mn(3+) in pure jacobsite, confirmed by XANES analysis, probably due to the synthesis conditions. PMID:18688375

Carta, Daniela; Casula, Maria Francesca; Mountjoy, Gavin; Corrias, Anna

2008-06-01

312

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

313

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

314

Fe3O4+? films prepared by ``one-liquid'' spin spray ferrite plating for gigahertz-range noise suppressors  

NASA Astrophysics Data System (ADS)

We have developed a simple type of ferrite film preparation technique, which we call ``one-liquid'' spin spraying method. Only one aqueous solution composed of dextran+FeCl2+CH3COOK+NaNO2 is sprayed onto spinning substrates, while, in our previous method, a reaction solution of FeCl2 (source) and an oxidizing solution of CH3COOK (pH buffer)+NaNO2 (oxidizer) were sprayed simultaneously. Dextran [(C6H12O6)n, n=1100-1700] suppresses iron hydroxides from precipitating in the aqueous solution. On optimized conditions, we deposited Fe3O4+? films to the thickness of 1.6 ?m for 30 min, obtaining film deposition rate of 52 nm/min. The films exhibited good performance of conducted noise suppression; we obtained loss parameter ?Ploss of 33% at 10 GHz of Fe3O4+? films, which was approximately equal to that obtained for the commercialized noise suppression of composite sheet type, and reflection loss parameter S11, less than -10 dB. Thus one-liquid method as well will provide a method to prepare the noise suppressors of Fe3O4+? films workable in the gigahertz range.

Miyasaka, Jin; Tada, Masaru; Abe, Masanori; Matsushita, Nobuhiro

2006-04-01

315

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

316

Preparation and characterization of spironolactone nanoparticles by antisolvent precipitation.  

PubMed

Due to low aqueous solubility and slow dissolution rate, spironolactone, a synthetic steroid diuretic, has a low and variable oral bioavailability. Nanoparticles were thus prepared by antisolvent precipitation in this work for accelerating dissolution of this kind of poorly water-soluble drugs. Effects of surfactant type/concentration and feed drug concentration on the precipitated particle size were evaluated. It was found that introduction of spironolactone solution in N-methyl-2-pyrrolidone (NMP) to the antisolvent water can produce the particles in the submicron range with hydroxypropyl methylcellulose (HPMC) as the stabilizer. The particle size decreased with the increase of HPMC concentration from 0 to 0.125% (w/v), further increase of which did not affect the size significantly. Increasing feed drug concentration from 10 to 100 mg/ml resulted in the particle size decrease. In comparison with raw drug, the chemical structure of nanosized spironolactone was not changed but the crystallinity was reduced. Dissolution of spironolactone nanoparticles in 0.1M HCl was 2.59 times faster than raw drugs in 60 min. PMID:19481693

Dong, Yuancai; Ng, Wai Kiong; Shen, Shoucang; Kim, Sanggu; Tan, Reginald B H

2009-06-22

317

Effect of Ti-containing inclusions on the nucleation of acicular ferrite and mechanical properties of multipass weld metals.  

PubMed

In the present study, the influence of Ti-containing inclusions on the development of acicular ferrite microstructure and mechanical properties in the multipass weld metals has been studied. Shielded metal arc weld deposits were prepared by varying titanium content in the range of 0.003-0.021%. The variation in the titanium content was obtained by the addition of different amounts of titanium oxide nanoparticles to the electrode coating. The dispersion of titanium oxide nanoparticles, composition of inclusions, microstructural analysis, tensile properties and Charpy impact toughness were evaluated. As the amount of Ti-containing inclusions in the weld metal was increased, the microstructure of the weld metal was changed from the grain boundary allotriomorphic ferrite structure to acicular ferrite with the intragranular nucleation of ferrite on the Ti-containing inclusions, and the mechanical properties were improved. This improvement is attributable to the increased percentage of acicular ferrite due to the uniform dispersion of Ti-containing inclusions and the pinning force of oxide nanoparticles against the growth of allotriomorphic ferrite and Widmanstätten ferrite from the austenite grain boundaries. PMID:23238108

Fattahi, M; Nabhani, N; Hosseini, M; Arabian, N; Rahimi, E

2013-02-01

318

Evaluation of iron-cobalt/ferrite core-shell nanoparticles for cancer thermotherapy  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles (MNPs) offer promise for local hyperthermia or thermoablative cancer therapy. Magnetic hyperthermia uses MNPs to heat cancerous regions in an rf field. Metallic MNPs have larger magnetic moments than iron oxides, allowing similar heating at lower concentrations. By tuning the magnetic anisotropy in alloys, the heating rate at a particular particle size can be optimized. Fe-Co core-shell MNPs have protective CoFe2O4 shell which prevents oxidation. The oxide coating also aids in functionalization and improves biocompatibility of the MNPs. We predict the specific loss power (SLP) for FeCo (SLP ˜450W /g) at biocompatible fields to be significantly larger in comparision to oxide materials. The anisotropy of Fe-Co MNPs may be tuned by composition and/or shape variation to achieve the maximum SLP at a desired particle size.

Habib, A. H.; Ondeck, C. L.; Chaudhary, P.; Bockstaller, M. R.; McHenry, M. E.

2008-04-01

319

Plasmonically enhanced Faraday effect in metal and ferrite nanoparticles composite precipitated inside glass.  

PubMed

Using femtosecond laser irradiation and subsequent annealing, nanocomposite structures composed of spinel-type ferrimagnetic nanoparticles (NPs) and plasmonic metallic NPs have been formed space-selectively within glass doped with both ?-Fe(2)O(3) and Al. The Faraday rotation spectra exhibit a distinct negative peak at around 400 nm, suggesting that the ferrimagnetic Faraday response is enhanced by the localized surface plasmon resonance (LSPR) due to metallic Al NPs. At the interfaces in the nanocomposites, the ferrimagnetism of magnetite NPs is directly coupled with the plasmon in the Al NPs. The control of the resonance wavelength of the magneto-optical peaks, namely, the size of plasmonic NPs has been demonstrated by changing the irradiation or annealing conditions. PMID:23263053

Nakashima, Seisuke; Sugioka, Koji; Tanaka, Katsuhisa; Shimizu, Masahiro; Shimotsuma, Yasuhiko; Miura, Kiyotaka; Midorikawa, Katsumi; Mukai, Kohki

2012-12-17

320

Microstructure and mechanical properties of oxide dispersion strengthened ferritic steel prepared by a novel route  

NASA Astrophysics Data System (ADS)

Nanocrystalline oxide dispersion strengthened (ODS) ferritic steel powders with nominal composition of Fe-14Cr-3W-0.2Ti-0.3Y was synthesized using a sol-gel method combining with hydrogen reduction. X-ray diffraction patterns show that pure Fe-14Cr-3W-0.2Ti-0.3Y body-centered-cubic phase was obtained at a reduction temperature of 1200 °C for 3 h. Using such powders the ODS steel was produced by spark plasma sintering (SPS) technique. The energy dispersive spectrometry mapping and transmission electron microscopy results indicate that the oxide particles of Y2Ti2O7 with an average size of 55 nm and particle number density of 3.2 × 1019 m-3 are homogeneously dispersed in the steel matrix. The tensile strength and uniform elongation of the steel that was SPS sintered and mechanically-thermally treated at 1100 °C under a uniaxial pressure reach 1070 MPa and 15%, respectively.

Sun, Q. X.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Hao, T.; Liu, C. S.

2012-05-01

321

Facile preparation of multicolor polymer nanoparticle bioconjugates with specific biorecognition.  

PubMed

A facile and efficient strategy to prepare multicolor and surface-functionalizable conjugated polymer nanoparticles (PPVseg-COOH CPNs) was demonstrated. The CPNs with tunable photoluminescence colors and carboxylate groups were further covalently modified with a series of specific molecules such as streptavidin, IgG and poly(ethylene glycol) to show their generality for subsequent bioconjugation and biological applications. The streptavidin coating can significantly improve the photostability of the PPVseg-SA CPNs, which indicates that specific biomolecules such as streptavidin functionalization of multicolor PPVseg-COOH CPNs can be applied to achieve high optical stability of CPNs in various buffer solutions, metal ions for many biological applications. Furthermore, the resulted PPVseg-SA CPNs also show efficient labeling ability in specific cellular imaging. The synthetic methods present the feasibility and versatility for further developing surface-functionalizable CPNs probes with full-color tunability for biological imaging and bioanalytical applications. PMID:24963877

Bao, Biqing; Ma, Mingfeng; Chen, Jia; Yuwen, Lihui; Weng, Lixing; Fan, Quli; Huang, Wei; Wang, Lianhui

2014-07-23

322

In situ preparation of monodispersed Ag/polyaniline/Fe3O4 nanoparticles via heterogeneous nucleation  

PubMed Central

Acrylic acid and styrene were polymerized onto monodispersed Fe3O4 nanoparticles using a grafting copolymerization method. Aniline molecules were then bonded onto the Fe3O4 nanoparticles by electrostatic self-assembly and further polymerized to obtain uniform polyaniline/Fe3O4 (PANI/Fe3O4) nanoparticles (approximately 35 nm). Finally, monodispersed Ag/PANI/Fe3O4 nanoparticles were prepared by an in situ reduction reaction between emeraldine PANI and silver nitrate. Fourier transform infrared and UV-visible spectrometers and a transmission electron microscope were used to characterize both the chemical structure and the morphology of the resulting nanoparticles. PMID:23819820

2013-01-01

323

Magnetic properties of Ba-M-type hexagonal ferrites prepared by the sol–gel method with and without polyethylene glycol added  

Microsoft Academic Search

Ba-M-type hexagonal ferrites have been prepared via a sol–gel route, and the effects of adding different amounts of polyethylene glycol (PEG 2000) into the sol solutions on their static magnetic properties and particle morphologies also have been studied. With increasing the amount of PEG added, it is found that both the saturation magnetization and the coercivity decreases. The magnetocrystalline anisotropy

Mangui Han; Yu Ou; Wenbing Chen; Longjiang Deng

2009-01-01

324

Fluorescent nanoparticles from starch: Facile preparation, tunable luminescence and bioimaging.  

PubMed

Fluorescent organic nanoparticles (FONs) based on carbohydrate polymers were prepared through one-pot hydrothermal treatment of starch in the presence of polyethyleneimine. These FONs (named as PEI-Starch FONs) were characterized by a series of techniques including UV-Vis absorption spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Results showed that the size of PEI-Starch FONs is 10-30nm. The PEI-Starch FONs exhibited high water dispersibility because of the existence of hydrophilic functional groups on their surface. After excited with different wavelength, PEI-Starch FONs emitted strong and excitation-dependent fluorescence. To evaluate their potential for biomedical applications, biocompatibility and cell uptake behavior of PEI-Starch FONs were further investigated. We demonstrated that PEI-Starch FONs are biocompatible with cells and can be easily internalized by cells within 3h. Taken together, novel FONs have been prepared via a simple and scalable hydrothermal method using starch and polyethyleneimine as precursors. These PEI-Starch FONs showed excellent fluorescence properties, high water dispersibility and good biocompatibility, making them highly potential for various biomedical applications. PMID:25659670

Liu, Meiying; Zhang, Xiqi; Yang, Bin; Li, Zhan; Deng, Fengjie; Yang, Yang; Zhang, Xiaoyong; Wei, Yen

2015-05-01

325

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

326

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

327

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

328

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

329

Investigation of antibacterial properties silver nanoparticles prepared via green method  

PubMed Central

Background This study aims to investigate the influence of different stirring times on antibacterial activity of silver nanoparticles in polyethylene glycol (PEG) suspension. The silver nanoparticles (Ag-NPs) were prepared by green synthesis method using green agents, polyethylene glycol (PEG) under moderate temperature at different stirring times. Silver nitrate (AgNO3) was taken as the metal precursor while PEG was used as the solid support and polymeric stabilizer. The antibacterial activity of different sizes of nanosilver was investigated against Gram–positive [Staphylococcus aureus] and Gram–negative bacteria [Salmonella typhimurium SL1344] by the disk diffusion method using Müeller–Hinton Agar. Results Formation of Ag-NPs was determined by UV–vis spectroscopy where surface plasmon absorption maxima can be observed at 412–437 nm from the UV–vis spectrum. The synthesized nanoparticles were also characterized by X-ray diffraction (XRD). The peaks in the XRD pattern confirmed that the Ag-NPs possessed a face-centered cubic and peaks of contaminated crystalline phases were unable to be located. Transmission electron microscopy (TEM) revealed that Ag-NPs synthesized were in spherical shape. The optimum stirring time to synthesize smallest particle size was 6 hours with mean diameter of 11.23 nm. Zeta potential results indicate that the stability of the Ag-NPs is increases at the 6 h stirring time of reaction. The Fourier transform infrared (FT-IR) spectrum suggested the complexation present between PEG and Ag-NPs. The Ag-NPs in PEG were effective against all bacteria tested. Higher antibacterial activity was observed for Ag-NPs with smaller size. These suggest that Ag-NPs can be employed as an effective bacteria inhibitor and can be applied in medical field. Conclusions Ag-NPs were successfully synthesized in PEG suspension under moderate temperature at different stirring times. The study clearly showed that the Ag-NPs with different stirring times exhibit inhibition towards the tested gram-positive and gram-negative bacteria. PMID:22839208

2012-01-01

330

The role of fuel concentration on particle size and dielectric properties of manganese substituted zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Mn substituted ZnFe2O4 nanoparticles were prepared by the auto-combustion method using different fuel ratios of 50%, 75% and 100%.The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectrum (EDX). Also, the dielectric behaviors of the samples were investigated for different annealing temperatures. The X-ray diffraction patterns indicated that the annealed samples resulted in the formation of crystalline powder and the presence of ?-Fe2O3 as a secondary phase. The average crystallite sizes of the samples are from ~12 to 60 nm. The external morphology and microstructure of the samples are tested by SEM and TEM. The effect of annealing temperature and particle size on dielectric properties such as dielectric constant (?) and dielectric loss (D) of the spinel MnxZn1-xFe2O4 nanoparticles was measured using impedance analyzer in the frequency range 100 kHz-5 MHz.

Ranjith Kumar, E.; Jayaprakash, R.

2014-10-01

331

Preparation and optical properties of colloidal silver nanoparticles at a high Ag + concentration  

Microsoft Academic Search

We have prepared colloidal silver nanoparticles by reducing a high molar concentration of AgNO3 (up to 0.735 M) with glycerol in the presence of m-phenylenediamine. These silver nanoparticles had anisotropic shapes, including truncated rectangles, truncated triangles, and spheroid-type particles. The UV–Vis spectra of these nanoparticle systems display two distinct plasmon modes and a shoulder that correspond to the in-plane dipole,

M. Habib Ullah; Kim Il; Chang-Sik Ha

2006-01-01

332

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

333

Optimizing coverage of metal oxide nanoparticle prepared by pulsed laser deposition on nonenzymatic glucose detection.  

PubMed

Metal oxide nanoparticles prepared by pulsed laser deposition (PLD) were applied to nonenzymatic glucose detection. NiO nanoparticles with size of 3 nm were deposited on glassy carbon (GC) and silicon substrates at room temperature in an oxygen atmosphere. Transmission electron microscope (TEM) image showed nanoparticles with the size of 3 nm uniformly scattered on the Si(001) substrate. Unlike co-sputtering nanoparticle and carbon simultaneously, the PLD method can easily control the surface coverage of nanoparticles on the surface of substrate by deposition time. Cyclic voltammetry was performed on the samples deposited on the GC substrates for electrochemical detection of glucose. The differences between peak currents with and without glucose was used to optimize the coverage of nanoparticles on carbon electrode. The results indicated that optimal coverage of nanoparticles on carbon electrode. PMID:21376990

Kaneko, Satoru; Ito, Takeshi; Hirabayashi, Yasuo; Ozawa, Takeshi; Okuda, Tetsuya; Motoizumi, Yu; Hirai, Kiyohito; Naganuma, Yasuhiro; Soga, Masayasu; Yoshimoto, Mamoru; Suzuki, Koji

2011-04-15

334

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

335

The preparation of barium ferrite nanocrystalline powders by a stearic acid gel method  

Microsoft Academic Search

A new stearic acid gel method has been shown to be suitable for preparing BaFe12O19 nanostructured powders with narrow particle size distribution. Each state of the synthetic process was followed by use of DTA, TG, IR and X-ray analysis. The particle size and morphology were determined by transmission electron microscopy. The chemical composition of these particles was consistent with that

Xiaohui Wang; Dan Li; Lude Lu; Xin Wang; Liansheng Zhang; Yihua Liu

1996-01-01

336

Dendrimer-encapsulated metal nanoparticle thin films on solid surfaces: preparation, characterization, and applications to electrocatalysis  

E-print Network

Dendrimer-encapsulated nanoparticles (DENs) were prepared, characterized, and immobilized on solid surfaces. The resulting films were applied as electrocatalysts for the oxygen reduction reaction (ORR). First, the synthesis, physical and chemical...

Ye, Heechang

2009-05-15

337

Effect of Particle Size on Hyperfine Fields in Cr?Substituted Nano Co?Zn Ferrite  

Microsoft Academic Search

Nanoparticles of chromium?substituted cobalt zinc ferrite CCZF (Cr0.25Co0.25Zn0.5Fe2O4) were prepared using a chemical co?precipitation technique. X?ray diffraction studies of the prepared material show that the particle size lies in the nano range, with the smallest crystallite size being around 5 nm. Crystallite sizes are seen to increase with increase in the annealing temperature. Fe?57 Mössbauer studies at room temperature show that

Ram Kripal Sharma; Omprakash Suwalka; N. Lakshmi; K. Venugopalan

2006-01-01

338

The Influence of Oleic Acid to Metal Nitrate Ratio on the Particle Size and Magnetic Properties of Lanthanum Ferrite Nanoparticles by Emulsion Method  

Microsoft Academic Search

LaFeO3 nanoparticles of different sizes are prepared by varying the molar concentration of oleic acid to metal nitrate using emulsion combustion method. X-ray diffraction analysis confirms that LaFeO3 nanoparticles are crystalline in nature with an orthorhombic structure. The average particle size and saturation magnetization decreases from 56 to 32 nm and 0.20 to 0.08 emu\\/g, as molar concentration of oleic acid to

Jeyaseelan Chandradass; Dong Sik Bae; M. Balasubramanian; Ki Hyeon Kim

2011-01-01

339

Preparation and properties of magnetic Fe 3O 4–chitosan nanoparticles  

Microsoft Academic Search

Magnetic Fe3O4–chitosan nanoparticles were prepared by the covalent binding of chitosan (CTS) onto the surface of magnetic Fe3O4 nanoparticles which were prepared by hydrothermal method using H2O2 as an oxidizer. Transmission electron microscopy (TEM) showed that Fe3O4 particles and Fe3O4–chitosan nanocomposites were regular sphere with a mean diameter of 23nm and 25nm, respectively. X-ray diffraction patterns (XRD) indicated that the

Gui-yin Li; Yu-ren Jiang; Ke-long Huang; Ping Ding; Jie Chen

2008-01-01

340

Preparation of a porous nanocrystalline TiO 2 layer by deposition of hydrothermally synthesized nanoparticles  

Microsoft Academic Search

In this work, a porous nanocrystalline anatase TiO2 layer is prepared by tape casting a viscous dispersion of nanoparticles. Phase pure anatase titanium dioxide nanoparticles with a particle size of 10–20nm are prepared by a very simple low temperature (100°C) hydrothermal synthesis route in a pressure vessel, using only water as the medium and Ti(IV)-isopropoxide as starting material without additives.

J. Beusen; M. K. Van Bael; H. Van den Rul; J. D’Haen; J. Mullens

2007-01-01

341

Preparation and characterization of nitrendipine solid lipid nanoparticles.  

PubMed

Nitrendipine, a dihydropyridine calcium channel blocker, has very poor oral bioavailability (10-20%) due to first pass effect. Solid lipid nanoparticle (SLN) delivery systems of nitrendipine have been developed using various triglycerides (trimyristin, tripalmitin and tristearin), soy phosphatidylcholine 95%, poloxamer 188 and charge modifiers stearylamine and dicetyl phosphate. SLNs were prepared by hot homogenization of melted lipids and aqueous phase followed by ultrasonication at temperatures above the melting point of lipids. Optimization studies of process and formulation variables were carried out. Particle size and zeta potential were measured by photon correlation spectroscopy (PCS) using Malvern zetasizer. Differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) studies were performed to characterize state of drug and lipid modification. In vitro release studies were performed in phosphate buffer pH 6.8 using modified Franz diffusion cell. Stable nitrendipine SLNs of mean size range 79 to 213 nm and zeta potential -38.2 to +34.6 mV were developed. About 99% nitrendipine was entrapped in SLNs and were stable on storage at 4 and 25 degrees C. DSC and PXRD analyses revealed that nitrendipine is dispersed in SLNs in an amorphous state. The release pattern of drug is analyzed and found to follow Weibull distribution rather than first order and Higuchi equation. PMID:21553647

Manjunath, K; Venkateswarlu, V; Hussain, A

2011-03-01

342

Fluorescence of silicon nanoparticles prepared by nanosecond pulsed laser  

NASA Astrophysics Data System (ADS)

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; Sui, Xin; Yang, Fang; Fu, Xing; Ma, Wei; Li, Jishun; Xue, Yujun

2014-03-01

343

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

344

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

345

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

346

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

347

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

348

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

349

Preparation, characterization and transfection efficacy of chitosan nanoparticles containing the intestinal trefoil factor gene.  

PubMed

Intestinal trefoil factor (ITF) is a novel polypeptide with potential pharmacological value for the prevention and healing of tissue injury; however, poor production capacity limits its clinical application. Chitosan, as a non-viral vehicle, has been successfully used in gene delivery for its intrinsic characteristics. In this context, we prepared chitosan nanoparticles enwrapping ITF cDNA and investigated its size, zeta potential, stability, release profiles, loading efficiency and loading capacity. Gene transfer capability was assessed in HEK293 cells. The data revealed that the chitosan/DNA nanoparticles were successfully prepared with sizes less than 500 nm and positive zeta potentials. The nanoparticles could protect DNA from nuclease degradation, and release profiles of DNA were dependent on N/P ratios. In addition, transfection efficiency of chitosan/DNA nanoparticles was equivalent to Lipofectamine (TM). Collectively, the results suggest that chitosan/DNA nanoparticles could be a promising method for ITF gene therapy. PMID:21573797

Sun, Yong; Zhang, Shuai; Peng, Xi; Gong, Zhenyu; Li, Xiaolu; Yuan, Zhiqiang; Li, Ying; Zhang, Dawei; Peng, Yizhi

2012-02-01

350

Control of Particle Size and Morphology of Cobalt-Ferrite Nanoparticles by Salt-Matrix during Annealing  

NASA Astrophysics Data System (ADS)

Salt-matrix annealing of mechanically alloyed Co-ferrite nanopowder was used to modify its particle size and morphology. Efficiency improvement due to suppression of sintering and growth resulted in reduction of average particle size from 100nm for salt-less to 40nm for salt-full annealing procedure. Nanosized single-phase cobalt-ferrite particles were observed after 2h annealing at 750°C in the samples milled for 20 hours both with and without NaCl. NaCl:CoFe2O4 ratio of 10:1 resulted in cabbage-like clusters containing particles smaller than 50 nm.

Azizi, A.; Sadrnezhaad, S. K.; Mostafavi, M.

351

Z Ferrite Composite  

NASA Astrophysics Data System (ADS)

Fe-Si-Al/Co2Z ferrite composites were prepared by ball-milling. The microstructure, microwave electromagnetic properties, and impedance-matching performance of a series of composites were determined and the results are discussed. Experimental results indicated that, in frequency range 1-18 GHz, the permittivity and permeability of the complexes can be adjusted by changing the Fe-Si-Al-to-Co2Z weight ratio. Calculated reflection losses indicate that the absorption performance of Fe-Si-Al/Co2Z ferrite composites is superior to that of the pure Fe-Si-Al and Co2Z ferrites. It was found that the impedance-matching performance of the materials, which contributes to perfect absorption, can be improved by use of an appropriate weight ratio for the Fe-Si-Al/Co2Z ferrite composite.

Li, Qifan; Feng, Zekun; Yan, Shuoqing; Nie, Yan; Wang, Xian

2014-09-01

352

Study of structure and magnetic properties of Ni-Zn ferrite nano-particles synthesized via co-precipitation and reverse micro-emulsion technique  

NASA Astrophysics Data System (ADS)

Nano-crystalline Ni-Zn ferrites were synthesized by chemical co-precipitation and reverse micro-emulsion technique with an average crystallite size of 11 and 6 nm, respectively. The reverse micro-emulsion method has been found to be more appropriate for nano-ferrite synthesis as the produced particles are monodisperse and highly crystalline. Zero-field cooled and field cooled magnetization study under different magnetic fields and magnetic hysteresis loops at different temperatures have been performed. The non-saturated M-H loops, absence of hysteresis, and coercivity at room temperature are indicative of the presence of super paramagnetic and single-domain nano-particles for both the materials. In sample `a', the blocking temperature ( T B) has been observed to decrease from 255 to 120 K on increasing the magnetic field from 50 to 1,000 Oe, which can be attributed to the reduction of magneto crystalline anisotropy constant. The M S and coercivity were found to be higher for sample `a' as compared with sample `b' since surface effects are neglected on increasing the crystallite size.

Abdullah Dar, M.; Shah, Jyoti; Siddiqui, W. A.; Kotnala, R. K.

2014-08-01

353

Preparation of ultrathin coating layers using surface modified silica nanoparticles  

Microsoft Academic Search

Silica nanoparticles are used in various applications including catalysts, paints and coatings. To reach an optimal performance via stability and functionality, in most cases, the surface properties of the particles are altered using complex procedures. Here we describe a simple method for surface modification of silica nanoparticles (SNP) using sequential adsorption of oppositely charged components. First, the SNPs were made

Tiina Nypelö; Monika Österberg; Xuejie Zu; Janne Laine

354

Preparation of L-Alanine Crystals Containing Gold Nanoparticles  

Microsoft Academic Search

Amino acids provide useful foods, medicines, health foods, and nutritional supplements. We studied the morphology control of alanine, an amino acid. We also studied the effects of amino acid addition on the dispersion stability of gold nanoparticles. We then studied hybridization between alanine crystals and arginine-capped gold nanoparticles. Alanine crystal growth in a supersaturated alanine solution was found to increase

Masako Koyama; Masaharu Shiraishi; Koji Sasaki; Kijiro Kon-no

2008-01-01

355

Preparation and electromagnetic properties of Polyaniline(polypyrrole)-BaFe12O19/Ni0.8Zn0.2Fe2O4 ferrite nanocomposites  

NASA Astrophysics Data System (ADS)

The nanocomposite of hard (BaFe12O19)/soft ferrite (Ni0.8Zn0.2 Fe2O4) was prepared by the sol-gel process, and then the polyaniline(PANI)/polypyrrole(PPY)-BaFe12O19/Ni0.8Zn0.2Fe2O4 was produced by in situ polymerization method. The structures, morphology and electromagnetic properties of the samples were characterized by various instruments. XRD, TEM, and FTIR analysis indicated that BaFe12O19/Ni0.8Zn0.2Fe2O4 ferrite were homogenously enwrapped by PANI(PPY) coating. The VSM and SDY-4 measurement show that the magnetic properties of the composites decreased with the increase in PANI(PPY) amount, However, the electrical conductivity is on the contrary. The electromagnetic properties of the composites were much better than BaFe12O19/Ni0.8Zn0.2Fe2O4 in the frequency range of 2-15 GHz, which mainly depends on the dielectric loss of PANI(PPY). A minimum reflection loss of the PANI(PPY)-BaFe12O19/Ni0.8Zn0.2Fe2O4 ferrite nanocomposite is -19.7 dB(-21.5 dB) at the frequency of 7.3 GHz (10.7 GHz).

Wang, Yan; Huang, Ying; Wang, Qiufen; He, Qian; Chen, Lin

2012-10-01

356

Catalytic oxidation of carbon monoxide over radiolytically prepared Pt nanoparticles supported on glass  

SciTech Connect

Platinum nanoparticles have been prepared by radiolytic and chemical methods in the presence of stabilizer gelatin and SiO{sub 2} nanoparticles. The formation of Pt nanoparticles was confirmed using UV-vis absorption spectroscopy and transmission electron microscopy (TEM). The prepared particles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at {>=}150 deg. C giving CO{sub 2}. Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave {approx}7% CO conversion per hour. However, radiolytically prepared Pt nanoparticles stabilized by gelatin gave {approx}10% conversion per hour. Catalytic activity of radiolytically prepared platinum catalyst, coated on the inner walls of the reactor, was evaluated as a function of CO concentration and reaction temperature. The rate of reaction increased with increase in reaction temperature and the activation energy for the reaction was found to be {approx}108.8 kJ mol{sup -1}. The rate of CO{sub 2} formation was almost constant ({approx}1.5 x 10{sup -4} mol dm{sup -3} h{sup -1}) at constant O{sub 2} concentration (6.5 x 10{sup -3} mol dm{sup -3}) with increase in CO concentration from 2 x 10{sup -4} mol dm{sup -3} to 3.25 x 10{sup -3} mol dm{sup -3}. The data indicate that catalytic oxidation of CO takes place by Eley-Rideal mechanism.

Kapoor, S. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)]. E-mail: sudhirk@apsara.barc.ernet.in; Belapurkar, A.D. [Applied Chemistry Division, Chemistry Group, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Mittal, J.P. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Mukherjee, T. [Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)]. E-mail: mukherji@magnum.barc.ernet.in

2005-10-06

357

[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

358

Stability, size and optical properties of colloidal silver nanoparticles prepared by electrical arc discharge in water  

NASA Astrophysics Data System (ADS)

We have fabricated and characterised colloidal silver nanoparticles by the electrical arc discharge method in DI water. Size and optical properties of the silver nanoparticles were studied versus different arc currents. Optical absorption indicates a plasmonic peak at 392 nm for 10 A which increases to 398 nm for 20 A arc current. This reveals that by raising the arc current the size of the nanoparticles increases. Optical absorption of silver nanoparticles after 3 weeks shows precipitation of them in a water medium. The effect of different surfactant and stabilizer concentrations such as cethyl trimethylammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), sodium citrate, sodium dodecyl sulfate (SDS), sodium di-2-ethylsulfosuccinate (AOT) and carboxymethyl cellulose (CMC) on the stability of silver nanoparticles was investigated. The colloidal silver nanoparticles with 100 ?M concentration were stable for more than 3 months at 50 ?M CTAB and 6 months at 10 ?M sodium citrate concentration, respectively. SEM images of the sample prepared at 50 ?M CTAB concentration reveal uniform and fine nanoparticles. The mean size from TEM images is about 14 nm. TEM images of the sample prepared at 10 ?M sodium citrate concentration show a shell of citrate that covers the silver nanoparticles.

Ashkarran, A. A.; Iraji Zad, A.; Ahadian, M. M.; Hormozi Nezhad, M. R.

2009-10-01

359

Rivastigmine-loaded PLGA and PBCA nanoparticles: Preparation, optimization, characterization, in vitro and pharmacodynamic studies  

Microsoft Academic Search

Sustained release nanoparticulate formulations of Rivastigmine tartrate (RT) were prepared, optimized (using factorial design) and characterized using the biodegradable polymers, PLGA and PBCA as carriers. The pharmacodynamic performances of the nanoparticles (NPs) were evaluated for brain targeting and memory improvement in scopolamine-induced amnesic mice using Morris Water Maze Test. PLGA NPs were prepared by nanoprecipitation technique, while PBCA NPs were

Shrinidh A. Joshi; Sandip S. Chavhan; Krutika K. Sawant

2010-01-01

360

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...

361

Synthesis and Characterization of Nickel Zinc Ferrite  

Microsoft Academic Search

Nano crystalline mixed ferrites can be prepared through different methods. In the present work a comparison was made on sol-gel auto combustion method and co-precipitation method by preparing Nickel Zinc Ferrite. The prepared samples were calcined at different temperatures and were characterized by powder XRD, FTIR. X-ray diffraction analysis indicated the formation of ferrite in nanophase. The lattice parameter was

Manju Kurian; Divya S. Nair

2011-01-01

362

Preparation of pure iron/Ni-Zn ferrite high strength soft magnetic composite by spark plasma sintering  

NASA Astrophysics Data System (ADS)

A dense microcellular structure is fabricated using micron-sized pure iron powder cladded with 10 wt% Zn0.5Ni0.5Fe2O4 nanopowder by filling the pure iron with Ni-Zn-ferrites composite and subjecting the mixture to a temperature of 600 °C. The SEM image shows that the thickness of cell wall is in the range of 1.0-2.0 ?m, and the inner dimension of the alloy is in the range of 15-40 ?m. By coating Ni-Zn-ferrites, the electrical resistivity is increased. The composite exhibits not only good soft magnetic properties but also good mechanical strength.

Wang, Minggang; Zan, Zhao; Deng, Na; Zhao, Zhankui

2014-06-01

363

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

364

Preparation and characterization of chemically functionalized silica-coated magnetic nanoparticles as a DNA separator.  

PubMed

The work describes a simple and convenient process for highly efficient and direct DNA separation with functionalized silica-coated magnetic nanoparticles. Iron oxide magnetic nanoparticles and silica-coated magnetic nanoparticles were prepared uniformly, and the silica coating thickness could be easily controlled in a range from 10 to 50 nm by changing the concentration of silica precursor (TEOS) including controlled magnetic strength and particle size. A change in the surface modification on the nanoparticles was introduced by aminosilanization to enhance the selective DNA separation resulting from electrostatic interaction. The efficiency of the DNA separation was explored via the function of the amino-group numbers, particle size, the amount of the nanoparticles used, and the concentration of NaCl salt. The DNA adsorption yields were high in terms of the amount of triamino-functionalized nanoparticles used, and the average particle size was 25 nm. The adsorption efficiency of aminofunctionalized nanoparticles was the 4-5 times (80-100%) higher compared to silica-coated nanoparticles only (10-20%). DNA desorption efficiency showed an optimum level of over 0.7 M of the NaCl concentration. To elucidate the agglomeration of nanoparticles after electrostatic DNA binding, the Guinier plots were calculated from small-angle X-ray diffractions in a comparison of the results of energy diffraction TEM and confocal laser scanning microscopy. Additionally, the direct separation of human genomic DNA was achieved from human saliva and whole blood with high efficiency. PMID:19099431

Kang, Kiho; Choi, Jinsub; Nam, Joong Hee; Lee, Sang Cheon; Kim, Kyung Ja; Lee, Sang-Won; Chang, Jeong Ho

2009-01-15

365

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

366

Sample preparation and EFTEM of Meat Samples for Nanoparticle Analysis in Food  

NASA Astrophysics Data System (ADS)

Nanoparticles are used in industry for personal care products and the preparation of food. In the latter application, their functions include the prevention of microbes' growth, increase of the foods nutritional value and sensory quality. EU regulations require a risk assessment of the nanoparticles used in foods and food contact materials before the products can reach the market. However, availability of validated analytical methodologies for detection and characterisation of the nanoparticles in food hampers appropriate risk assessment. As part of a research on the evaluation of the methods for screening and quantification of Ag nanoparticles in meat we have tested a new TEM sample preparation alternative to resin embedding and cryo-sectioning. Energy filtered TEM analysis was applied to evaluate thickness and the uniformity of thin meat layers acquired at increasing input of the sample demonstrating that the protocols used ensured good stability under the electron beam, reliable sample concentration and reproducibility.

Lari, L.; Dudkiewicz, A.

2014-06-01

367

Preparation and enzymatic hydrolysis of nanoparticles made from single xyloglucan polysaccharide chain.  

PubMed

In this work, polysaccharide nanoparticles based on tamarind seeds xyloglucan are prepared, analyzed in term of characteristic sizes and morphology, and degraded by the action of a glycoside-hydrolase. Obtained in an aqueous NaNO2 solution (0.1M), these unaggregated nanoparticles have a characteristic diameter of ca. 60 nm (DLS, AFM and TEM measures). They are not compact, but highly swollen and look like hyperbranched and dendrimer-like (soft sphere model) structures. This observation is coherent with the native structure of the xyloglucan macromolecules which are themselves branched. The enzymatic hydrolysis by cellulase of Trichoderma reesei of the xyloglucan nanoparticles is investigated. In particular, the apparent mass molecular weight drastically decreases meaning that the xyloglucan nanoparticles are effectively fully hydrolyzed by the endo-?-(1,4)-glucanase. Furthermore, we observe that the enzyme has to uncoil the nanoparticles before cutting the ?-(1?4) bonds and digesting the xyloglucan. PMID:23544652

Mkedder, Ilham; Travelet, Christophe; Durand-Terrasson, Amandine; Halila, Sami; Dubreuil, Frédéric; Borsali, Redouane

2013-05-15

368

Structure and magnetic properties of Ni x Zn 1? x Fe 2O 4 nanoparticles prepared through co-precipitation method  

Microsoft Academic Search

Nickel zinc ferrites, NixZn1?xFe2O4, nanoparticles have been synthesized using the chemical co-precipitation technique. Effects of synthesis conditions on the crystal structure, crystallite size, lattice parameter, microstructure and magnetic properties of the produced spinel ferrites were investigated by X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The results showed that a well crystalline single cubic structure

M. M. Rashad; E. M. Elsayed; M. M. Moharam; R. M. Abou-Shahba; A. E. Saba

2009-01-01

369

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

370

Facile Preparation of Danazol Nanoparticles by High-Gravity Antisolvent Precipitation (HGAP) Method  

Microsoft Academic Search

The nanoparticles of the hydrophobic drug of danazol with narrow size distribution are facilely prepared by controlled high-gravity anti-solvent precipitation (HGAP) process. Intensified micromixing and uniform nucleation environment are created by the high-gravity equipment (rotating packed bed) in carrying out the anti-solvent precipitation process to produce nanoparticles. The average particle size decreases from 55 ?m of the raw danazol to

Hong ZHAO; Jiexin WANG; Haixia ZHANG; Zhigang SHEN; Jimmy Yun; Jianfeng CHEN

2009-01-01

371

Magnetic chitosan\\/iron (II, III) oxide nanoparticles prepared by spray-drying  

Microsoft Academic Search

Chitosan\\/iron (II, III) oxide nanoparticles with various ratios of chitosan\\/iron (CS1\\/Fe4, CS2\\/Fe4 and CS3\\/Fe4) were prepared by a spray-drying method. Atomic absorption spectrometry (AAS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) spectrometry data confirm that magnetic crystalline Fe3O4 interacts with chitosan and distributes in the chitosan matrix. Field emission scanning electron microscopy (FESEM) micrographs indicate that nanoparticles so

Hsin-Yi Huang; Yeong-Tarng Shieh; Chao-Ming Shih; Yawo-Kuo Twu

2010-01-01

372

Preparation and characterization of Saccharomyces cerevisiae alcohol dehydrogenase immobilized on magnetic nanoparticles  

Microsoft Academic Search

The covalently immobilized of Saccharomyces cerevisiae alcohol dehydrogenase (SCAD) to magnetic Fe3O4 nanoparticles via glutaraldehyde coupling reaction was studied. The magnetic Fe3O4 nanoparticles were prepared by hydrothermal method using H2O2 as an oxidizer. Functionalization of surface-modified magnetic particles was performed by the covalent binding of chitosan onto the surface. The amino functional group on the magnetic Fe3O4-chitosan particles surface and

Gui Yin Li; Ke Long Huang; Yu Ren Jiang; Dong Liang Yang; Ping Ding

2008-01-01

373

Preparation and characterization of magnetic chitosan nanoparticles and its application for Cu(II) removal  

Microsoft Academic Search

The magnetic chitosan nanoparticles were prepared by a simple one-step in situ co-precipitation method and characterized by means of X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier Transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and energy dispersive X-ray spectrometer (EDS). The sorption performance of the nanoparticles for removing Cu(II) from aqueous solution was investigated. The experimental results showed that

Chen Yuwei; Wang Jianlong

2011-01-01

374

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

375

Preparation and in vitro characterization of novel bioactive glass ceramic nanoparticles  

Microsoft Academic Search

SiO(2)-CaO-P(2)O(5) ternary bioactive glass ceramic (BGC) nanoparticles\\u000d\\u000a with different compositions were prepared via a three-step sol-gel\\u000d\\u000a method. Polyethylene glycol was selected to be used as the surfactant to\\u000d\\u000a improve the dispersion of the nanoparticles. The morphology and\\u000d\\u000a composition of these BGC nanoparticles were observed by ESEM and EDX.\\u000d\\u000a All the BGC particles obtained in this method were about 20 nm

Zhongkui Hong; Rui L. Reis; Joao F. Mano

2009-01-01

376

Preparation, Physicochemical Characterization and Performance Evaluation of Gold Nanoparticles in Radiotherapy  

PubMed Central

Purpose: The aim of the present study was preparation, physicochemical characterization and performance evaluation of gold nanoparticles (GNPs) in radiotherapy. Another objective was the investigation of anti-bacterial efficacy of gold nanoparticle against E. coli clinical strains. Methods: Gold nanoparticles prepared by controlled reduction of an aqueous HAuCl4 solution using Tri sodium citrate. Particle size analysis and Transmission electron microscopy were used for physicochemical characterization. Polymer gel dosimetry was used for evaluation of the enhancement of absorbed dose. Diffusion method in agar media was used for investigation of anti-bacterial effect. Results: Gold nanoparticles synthesized in size range from 57 nm to 346 nm by planning different formulation. Gold nanoparticle in 57 nm size increased radiation dose effectiveness with the magnitude of about 21 %. At the concentration of 400 ppm, Nano gold exhibited significant anti-bacterial effect against E. coli clinical strains. Conclusion: It is concluded that gold nanoparticles can be applied as dose enhancer in radiotherapy. The Investigation of anti-bacterial efficacy showed that gold nanoparticle had significant effect against E. coli clinical strains. PMID:24312871

Kamiar, Ali; Ghotalou, Reza; Valizadeh, Hadi

2013-01-01

377

A Redox-Active Two-Dimensional Coordination Polymer: Preparation of Silver and Gold Nanoparticles and Crystal  

E-print Network

, diameter) nanoparticles were formed by the redox reactions between Ni(II) ions incorporated in 1 and metal reaction. We also reported that the redox-active coordination polymer produced silver nanoparticles of 3 nmA Redox-Active Two-Dimensional Coordination Polymer: Preparation of Silver and Gold Nanoparticles

Paik Suh, Myunghyun

378

Structural and magnetic properties of La3+ substituted strontium hexaferrite nanoparticles prepared by citrate precursor method  

NASA Astrophysics Data System (ADS)

Lanthanum (La3+) doped strontium ferrite is a promising material for high density perpendicular recording media due to high magnetocrystalline anisotropy and coercivity. The effects of La3+ on magnetic properties have been analyzed using vibrating sample magnetometer and discussed. The results show that the coercivity has been improved by substitution of La3+ on iron sites; coercivity value found to be increased with increase in La3+ content and is maximum for x=0.63 in SrLaxFe12-xO19, indicating the high magnetocrystalline anisotropy. La3+ doped strontium ferrite, prepared by citrate precursor technique, have been analyzed by means of X-ray diffraction (XRD), field emission scanning electron microscopy, fourier transform infrared spectroscopy and inductance capacitance resistance meter bridge. The XRD analysis shows that crystalline ferrite phase with hexagonal structure (P63/mmc) have been formed when the precursor calcined at 900 °C for 5 h. The crystallite size is found in the range of 31-38 nm and the elemental composition has been examined by energy dispersive X-ray. The dc electrical resistivity has been found to be increased with increasing La3+ content.

Thakur, Ankush; Singh, R. R.; Barman, P. B.

2013-01-01

379

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

380

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

381

Structural, electrical and magnetic studies of nickel-zinc nanoferrites prepared by simplified sol-gel and co-precipitation methods  

Microsoft Academic Search

Ferrite nanoparticles, particularly nickel-zinc ferrite nanoparticles, are novel materials for high-frequency applications. Nanoparticles with a composition of Ni0.5Zn0.5Fe2O4 were prepared by two different processes, namely the co-precipitation and simplified sol-gel methods. Powder x-ray diffraction (XRD) patterns confirmed the single-phase spinel structure for the as-prepared samples. Samples were sintered at 555 and 755 °C, after which the structural, electrical and magnetic

S. Nasir; M. Anis-ur-Rehman

2011-01-01

382

Preparation and characterization of chitosan/?-cyclodextrin nanoparticles containing plasmid DNA encoding interleukin-12.  

PubMed

Interleukin-12 (IL-12) as a cytokine has been proved to possess antitumor effects via stimulating the immune system. Non-viral gene delivery systems offer several advantages, including easiness in production, low cost, safety; low immunogenicity and can carry higher amounts of genetic material without limitation on their sizes.pUMVC3-hIL12 loaded Low Molecular Weight chitosan/?-cyclodextrin (LMW CS/CD) nanoparticles were prepared using ionotropic gelation method and characterized in terms of size, zeta potential, polydispersity index, morphology, loading efficiency and cytotoxicity against the CT-26 colon carcinoma cell line.All prepared particles were spherical in shape and nano-sized (171.3±2.165 nm, PdI: 0.231±0.014) and exhibited a positive zeta potential (34.3±1.55). The nanoparticles demonstrated good DNA encapsulation efficiencies (83.315%±2.067). Prepared pUMVC3-hIL12 loaded LMW CS/CD nanoparticles showed no cell toxicity in murine CT-26 colon carcinoma cells. At the concentration of 0.1 µg/ml of nanoparticles, the transfection ability was obviously higher than that of the naked DNA.LMW CS/CD-plasmid DNA nanoparticles encoding IL-12 prepared using ionotropic gelation method with no toxic effect on the tested cells can be considered as a basis for further gene delivery studies both in vitro and in vivo to enhance the expression of IL-12. PMID:23447042

Nahaei, M; Valizadeh, H; Baradaran, B; Nahaei, M R; Asgari, D; Hallaj-Nezhadi, S; Dastmalchi, S; Lotfipour, F

2013-01-01

383

Studies of Fe 3O 4-chitosan nanoparticles prepared by co-precipitation under the magnetic field for lipase immobilization  

Microsoft Academic Search

A simple method was introduced to prepare magnetic Fe3O4-chitosan nanoparticles by co-precipitation with 0.45T static magnetic field via glutaraldehyde cross-linking reaction, and the nanoparticles were used to immobilize lipase. The influence of magnetic field on the properties of magnetic nanoparticles was studied by SEM, XRD and VSM. The results showed that no obvious difference of the nanoparticles structure was found,

Yong Liu; Shaoyi Jia; Qian Wu; Jingyu Ran; Wei Zhang; Songhai Wu

2011-01-01

384

Preparation and characteristics of carboplatin-Fe@C-loaded chitosan nanoparticles with dual physical drug-loaded mechanisms  

Microsoft Academic Search

The present work is intended to set up the optimal carboplatin-Fe@C-loaded chitosan nanoparticles method and to compare and assess carboplatin-Fe@C-loaded with carboplatin-Fe-loaded chitosan nanoparticles. Both kinds of nanoparticles were prepared by a reverse microemulsion method. The carboplatin-Fe@C-loaded chitosan nanoparticles consisted of Fe@C nanopowder with the adsorbed drug as the magnetic core, chitosan as the matrix and carboplatin as the model

Yue-Hua Guo; Fu-Rong Li; Shi-Yun Bao; Tao Han; Jun-Jian Cao; Han-Xin Zhou

2007-01-01

385

Optimized method for preparation of TiO2 nanoparticles dispersion for biological study.  

PubMed

The objective of the present study was to develop a practical method to prepare a stable dispersion of TiO2 nanoparticles for biological studies. To address this matter a variety of different approaches for suspension of nanoparticles were conducted. TiO2 (rutile/anatase) dispersions were prepared in distilled water following by treated with different ultrasound energies and various dispersion stabilizers (1.0% carboxymethyl cellulose, 0.5% hydroxypropyl methyl cellulose K4M, 100% fetal bovine serum, and 2.5% bovine serum albumin). The average size of dispersed TiO2 (rutile/anatase) nanoparticles was measured by dynamic light scattering device. Agglomerate sizes of TiO2 in distilled water and 100% FBS were estimated using TEM analysis. Sedimentation rate of TiO2 (rutile/anatase) nanoparticles in dispersion was monitored by optical absorbance detection. In vitro cytotoxicity of various stabilizers in 16-HBE cells was measured using MTT assay. The optimized process for preparation of TiO2 (rutile/anatase) nanoparticles dispersion was first to vibrate the nanoparticles by vortex and disperse particles by ultrasonic vibration in distilled water, then to add dispersion stabilizers to the dispersion, and finally to sonicate the nanoparticles in dispersion. TiO2 (rutile/anatase) nanoparticles were disaggregated sufficiently with an ultrasound energy of 33 W for 10 min. The formation of TiO2 (rutile/anatase) agglomerates in distilled water was decreased obviously by addition of 1.0% CMC, 0.5% HPMC K4M, 100% FBS and 2.5% BSA. For the benefit of cell growth, FBS is the most suitable stabilizer for preparation of TiO2 (rutile/anatase) particle dispersions and subsequent investigation of the in vivo and in vitro behavior of TiO2 (rutile/anatase) nanoparticles. This method is practicable to prepare a stable dispersion of TiO2 (rutile/anatase) nanoparticles for at least 120 h. PMID:21125873

Zhang, Xiaoqiang; Yin, Lihong; Tang, Meng; Pu, Yuepu

2010-08-01

386

Electrical and magnetic characterization of nanocrystalline Ni–Zn ferrite synthesis by co-precipitation route  

Microsoft Academic Search

Nickel zinc ferrite nanoparticles Ni1?xZnxFe2O4 (x=0.25, 0.5, 0.75, 1) have been prepared by the chemical co-precipitation route. The samples were characterized by X-ray diffraction (XRD), DC electrical resistivity, dielectric constant and low field AC magnetic susceptibility. The powder XRD patterns confirm the single phase spinel structure for the synthesized materials. The crystallite size was calculated from the most intense peak

I. H. Gul; W. Ahmed; A. Maqsood

2008-01-01

387

Mechanical and Magnetic Properties of Thermoplastic Natural Rubber Nanocomposites Filled with Barium Ferrit  

Microsoft Academic Search

This study was undertaken to investigate the mechanical and magnetic properties of thermoplastic natural rubber (TPNR) filled with barium ferrite BaFe12O19 nanoparticle. The nanocompasites were prepared via melt blending method using the Haake 600 p internal mixer. The content of the filler is varied from 2–10% by volume fraction. TPNR is a blend of polypropylene (PP), liquid natural rubber (LNR)

Mohamed M. M. Milad; Sahrim Hj. Ahmad; S. Y. Yahya; Mou’ad. A. Tarawneh

2009-01-01

388

Mechanical and Magnetic Properties of Thermoplastic Natural Rubber Nanocomposites Filled with Barium Ferrit  

Microsoft Academic Search

This study was undertaken to investigate the mechanical and magnetic properties of thermoplastic natural rubber (TPNR) filled with barium ferrite BaFe12O19 nanoparticle. The nanocompasites were prepared via melt blending method using the Haake 600 p internal mixer. The content of the filler is varied from 2-10% by volume fraction. TPNR is a blend of polypropylene (PP), liquid natural rubber (LNR)

Mohamed M. M. Milad; Sahrim Hj. Ahmad; S. Y. Yahya; Mou'ad. A. Tarawneh

2009-01-01

389

Silk fibroin nanoparticles prepared by electrospray as controlled release carriers of cisplatin.  

PubMed

To maintain the anti-tumor activity of cis-dichlorodiamminoplatinum (CDDP) while avoiding its cytotoxicity and negative influence on normal tissue, CDDP-loaded silk fibroin nanoparticles approximately 59 nm in diameter were successfully prepared by electrospray without using organic solvent. CDDP was incorporated into nanoparticles through metal-polymer coordination bond exchange. In vitro release tests showed that the cisplatin in the nanoparticles could be slowly and sustainably released for more than 15 days. In vitro anti-cancer experiments and intracellular Pt content testing indicated that CDDP-loaded silk fibroin nanoparticles were easily internalized by A549 lung cancer cells, transferring CDDP into cancer cells and then triggering their apoptosis. In contrast, the particles were not easily internalized by L929 mouse fibroblast cells and hence showed weaker cell growth inhibition. The CDDP-loaded silk fibroin nanoparticles showed sustained and efficient killing of tumor cells but weaker inhibition of normal cells. In general, this study provides not only a novel method for preparing CDDP-loaded silk fibroin nanoparticles but also a new carrier system for clinical therapeutic drugs against lung cancers and other tumors. PMID:25280693

Qu, Jing; Liu, Yu; Yu, Yanni; Li, Jing; Luo, Jingwan; Li, Mingzhong

2014-11-01

390

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

391

Co-Pt nanoparticles encapsulated in carbon cages prepared by sonoelectrodeposition.  

PubMed

Co-Pt nanoparticles encapsulated in carbon cages have been prepared by sonoelectrodeposition followed by annealing in a CO atmosphere. Sonoelectrodeposition is a useful technique to make metallic nanoparticles, using ultrasound during electrodeposition to remove nanoparticles as they grow on the cathode surface. We used an electrolyte containing chloroplatinic acid and cobalt chloride and found that the atomic ratio of Co:Pt in the as-formed materials varied from 0.2 to 0.8 as the deposition current density was changed from 15 to 35 mA cm(-2). However, the as-deposited materials were inhomogeneous, comprising a mixture of Pt-rich and Co-rich nanoparticles. X-ray diffraction indicated that subsequent heat treatment (700?°C for 1 h) under CO gas created an ordered CoPt alloy phase that exhibited hard magnetic properties. Transmission electron microscopy showed many of the resulting nanoparticles to be encapsulated in carbon cages, which we ascribe to Co-catalyzed decomposition of CO during annealing. The thickness of the carbon cages was about ten layers, which may have helped reduce sintering during annealing. The size of the resultant nanoparticles was about 100 nm diameter, larger than the typical 5-10 nm diameter of as-deposited nanoparticles. PMID:21642760

Nguyen, Hoang Luong; Nguyen, Hoang Hai; Nguyen, Dang Phu; MacLaren, D A

2011-07-15

392

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

393

Green preparation and characterisation of waxy maize starch nanoparticles through enzymolysis and recrystallisation.  

PubMed

Waxy maize starch was treated by a facile and green enzymolysis procedure to fabricate starch nanoparticles (StNPs). The yield of StNPs was raised to 85% by pullulanase treatment, and the preparation duration was two days. Morphology (SEM, TEM), crystalline structure (XRD), thermal gravimetry analysis (TGA), and the group changing (FTIR) of StNPs prepared with different starch concentrations (10%, 15%, 20% and 25%,w/v) were investigated. Compared with native starch, the topography of all StNPs exhibited irregularly-shaped fragments, the particle diameters decreased from several ?m to about 60-120 nm, and the crystal pattern changed from A-type to B+V-type. The StNPs prepared with 15% starch slurry had the highest degree of crystallinity at 55.41%. The eco-friendly prepared nanoparticles could be widely used in biomedical applications and development of new materials. PMID:24874379

Sun, Qingjie; Li, Guanghua; Dai, Lei; Ji, Na; Xiong, Liu

2014-11-01

394

Epigallocatechin-3-gallate-capped Ag nanoparticles: preparation and characterization.  

PubMed

We used an aqueous leaf extract of Camellia sinensis to synthesize Ag nanoparticles (AgNPs). A layer of ca. 6 nm around a group of the AgNPs in which the inner layer is bound to the AgNPs surface via the hydroxyl groups of catechin has been observed. TEM analysis of AgNPs showed the formation of truncated triangular nanoplates and/or nanodisks and spherical with some irregular-shaped polydispersed nanoparticles in absence and presence of shape-directing cetyltrimethylammonium bromide. The polyphenolic groups of epigallocatechin-3-gallate (EGCG) are responsible for the rapid reduction of Ag(+) ions into metallic Ag(0). The free -OH groups are able to stabilize AgNPs by the interaction between the surface Ag atoms of AgNPs and oxygen atoms of EGCG molecules. PMID:24297160

Hussain, Shokit; Khan, Zaheer

2014-07-01

395

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

396

Preparation and characterization of 6-mercaptopurine-coated magnetite nanoparticles as a drug delivery system  

PubMed Central

Background Iron oxide nanoparticles are of considerable interest because of their use in magnetic recording tape, ferrofluid, magnetic resonance imaging, drug delivery, and treatment of cancer. The specific morphology of nanoparticles confers an ability to load, carry, and release different types of drugs. Methods and results We synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate “burst release” and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line. Conclusion Iron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and tissue. PMID:24106420

Dorniani, Dena; Hussein, Mohd Zobir bin; Kura, Aminu Umar; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

2013-01-01

397

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

398

Effective preparation of graphite nanoparticles using mechanochemical solid-state reactions  

NASA Astrophysics Data System (ADS)

The mechanochemical milling was utilized to control the nanostructures of plate-like graphite (Gp) microparticles in an argon atmosphere and at room temperature. The aggregated Gp nanoparticles were prepared by the simple solid-state process without organic solvent. Electron microscope observations, X-ray diffraction patterns and Raman spectra revealed the fractured plate-like Gp microparticles as well as the Gp microparticles agglomerated to each other through the dissociative edge surfaces by the milling process to finally generate the Gp nanoparticle aggregates. In the process, the ratio of the edge plane surfaces with the dangling bondings to layered internal surfaces clearly increased with the milling. Therefore, the low environmental burden process for preparing the Gp nanoparticle aggregation was achieved.

Motozuka, S.; Tagaya, M.; Ogawa, N.; Fukui, K.; Nishikawa, M.; Shiba, K.; Uehara, T.; Kobayashi, T.

2014-07-01

399

Structural and spectroscopic characterization of prepared Ag2S nanoparticles with a novel sulfuring agent.  

PubMed

Ag2S nanoparticles were prepared by a solvothermal process via reaction of Ag(NO3) and a new sulfuring agent from class of thio Schiff-base (2-(benzylidene amino) benzenethiol (C13H11NS)) in presence of various solvents. Spectra such as X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SEAD), ultraviolet-visible (UV-Vis) spectroscopy, thermo gravimetric-differential thermal analysis (TG-DTA), and Fourier transform Infrared (FT-IR) employed to characterize the synthesized products. Results of this paper indicate that shape and size of the silver sulfide can be controlled by means of setting certain reaction parameters such as the reaction temperature, presence of surfactant, and type of solvent. Silver sulfide nanoparticles with different morphology and size successfully prepared. In addition, the growth mechanisms of the Ag2S nanoparticles discussed preliminarily. PMID:24973787

Shakouri-Arani, Maryam; Salavati-Niasari, Masoud

2014-12-10

400

Preparation and Evaluation of Miconazole Nitrate-Loaded Solid Lipid Nanoparticles for Topical Delivery  

Microsoft Academic Search

The purpose of this study was to prepare miconazole nitrate (MN) loaded solid lipid nanoparticles (MN-SLN) effective for topical\\u000a delivery of miconazole nitrate. Compritol 888 ATO as lipid, propylene glycol (PG) to increase drug solubility in lipid, tween\\u000a 80, and glyceryl monostearate were used as the surfactants to stabilize SLN dispersion in the SLN preparation using hot homogenization\\u000a method. SLN

Mangesh R. Bhalekar; Varsha Pokharkar; Ashwini Madgulkar; Nilam Patil; Nilkanth Patil

2009-01-01

401

Size Controlled Synthesis of Gold Nanoparticles using Photochemically Prepared Seed Particles  

Microsoft Academic Search

Gold nanoparticles having prechosen size ranging from 5 to 110 nm have been prepared in two steps. Firstly, small spherical particles (seed) of average diameters between 5 and 20 nm were prepared by varying the ratio of gold ion concentration to stabilizer\\/reductant, TX-100 concentration and using UV irradiation. Secondly, 20–110 nm particles were formed by a non-iterative seed-mediated growth where

Tapan K. Sau; Anjali Pal; N. R. Jana; Z. L. Wang; Tarasankar Pal

2001-01-01

402

Experimental The average size of the silver nanoparticles, prepared by the method of Kor-  

E-print Network

Experimental The average size of the silver nanoparticles, prepared by the method of Kor- gel, with approximate molecular weight of 900 000, was then added to 0.5 mg of these silver nanocrystals in a vial, and radically improved photochemical reactors.[1±6] Colloidal self-assembly has been suggested as an efficient

Braun, Paul

403

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

404

Paraquat-loaded alginate\\/chitosan nanoparticles: Preparation, characterization and soil sorption studies  

Microsoft Academic Search

Agrochemicals are amongst the contaminants most widely encountered in surface and subterranean hydrological systems. They comprise a variety of molecules, with properties that confer differing degrees of persistence and mobility in the environment, as well as different toxic, carcinogenic, mutagenic and teratogenic potentials, which can affect non-target organisms including man. In this work, alginate\\/chitosan nanoparticles were prepared as a carrier

Mariana dos Santos Silva; Daniela Sgarbi Cocenza; Renato Grillo; Nathalie Ferreira Silva de Melo; Paulo Sérgio Tonello; Luciana Camargo de Oliveira; Douglas Lopes Cassimiro; André Henrique Rosa; Leonardo Fernandes Fraceto

2011-01-01

405

Two modelling data analytical methods applied to optimise the preparation of norcantharidin chitosan nanoparticles  

Microsoft Academic Search

In our study, the non-linear regression model and artificial neural networks (ANNs) were used to optimise the preparation of the loading norcantharidin chitosan nanoparticles (NPs) by ionic cross-linkage. Two major indexes, the particle size and the entrapment efficiency of the drug vehicles were synchronously optimised according to the normalised value calculated referring to the weights of the indexes and factors.

Wei Zhang; Yang Liu; Xiao-Yan Chen; Yong-Yan Bei; Jing-Yu Xu; Wen-Juan Wang; Xue-Nong Zhang; Qiang Zhang

2010-01-01

406

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...

407

Structural and electric properties of zinc substituted NiFe2O4 nanoparticles prepared by co-precipitation method  

Microsoft Academic Search

The electric properties of Ni1-xZnxFe2O4 ferrites (with x=0.0-0.7, in steps of x=0.1) prepared by wet chemical co-precipitation method have been studied as a function of frequency, temperature and composition. The broad XRD peaks of green samples and TEM image confirm the nano-dimensional nature of the prepared samples. Dispersion in the dielectric constant with frequency is observed and dielectric loss also

Santosh S. Jadhav; Sagar E. Shirsath; B. G. Toksha; S. M. Patange; D. R. Shengule; K. M. Jadhav

2010-01-01

408

Structural and electric properties of zinc substituted NiFe 2O 4 nanoparticles prepared by co-precipitation method  

Microsoft Academic Search

The electric properties of Ni1?xZnxFe2O4 ferrites (with x=0.0–0.7, in steps of x=0.1) prepared by wet chemical co-precipitation method have been studied as a function of frequency, temperature and composition. The broad XRD peaks of green samples and TEM image confirm the nano-dimensional nature of the prepared samples. Dispersion in the dielectric constant with frequency is observed and dielectric loss also

Santosh S. Jadhav; Sagar E. Shirsath; B. G. Toksha; S. M. Patange; D. R. Shengule; K. M. Jadhav

2010-01-01

409

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

410

Transmetallation as an effective strategy for the preparation of bimetallic CoPd and CuPd nanoparticles  

NASA Astrophysics Data System (ADS)

The preparation of palladium alloy nanoparticles is of great interest for many applications, especially in catalysis. Starting from presynthesized nanoparticles of a less noble metal, a transmetallation reaction involving a redox process at the nanoparticle surface can be exploited to modify the nanoparticle composition and crystalline phase. As an example, monodispersed ?-cobalt and face-centered cubic copper nanoparticles were synthesized in organic solvents at high temperature and the as-formed nanoparticles were reacted with palladium(ii) hexafluoroacetylacetonate resulting in the formation of alloyed nanoparticles whose composition closely follows the reactant ratio. The oxidative state of the nanoparticle surface greatly affects the success of the transmetallation reaction and a reduction treatment was necessary to achieve the desired final product. Electron microscopy and X-ray diffraction showed that for cobalt a limiting palladium content for the ?-phase alloy is found, above which an fcc alloy nucleates, while for copper the fcc crystalline phase is preserved throughout the whole composition range.

Bersani, Marco; Conte, Luca; Martucci, Alessandro; Guglielmi, Massimo; Mattei, Giovanni; Bello, Valentina; Rosei, Renzo; Centazzo, Massimo

2014-01-01

411

Novel combustion method to prepare octahedral NiO nanoparticles and its photocatalytic activity  

SciTech Connect

Graphical abstract: - Highlights: • NiO nanoparticles were synthesized by solution combustion method. • Prepared NiO nanoparticles are fcc structure. • Synthesized NiO nanoparticles are octahedral shape. • Shows good photocatalytic activity. - Abstract: Nickel oxide nanoparticles (NiO NPs) were synthesized by solution combustion method using glycine and citric acid as fuels. The X-ray diffraction (XRD) result confirms the face centered cubic (fcc) structure of NiO. The octahedral shape of NiO NPs was confirmed by field emission scanning electron microscope (FESEM) and high resolution transmission electron microscopy (HRTEM). It is possible to suggest that the organic fuel (citric acid/glycine) is responsible for the formation of the octahedral shape due to the easier complex formation. Photocatalytic activity of NiO NPs also evaluated and found that the prepared NiO NPs have high photocatalytic degradation. In the present study, the crystalline nature and shape of the NiO nanoparticles plays a vital role in determining the photocatalytic activity.

Jegatha Christy, A.; Umadevi, M., E-mail: ums10@yahoo.com

2013-10-15

412

Preparation of Biocompatible Carboxymethyl Chitosan Nanoparticles for Delivery of Antibiotic Drug  

PubMed Central

Objective. To prepare biocompatible ciprofloxacin-loaded carboxymethyl chitosan nanoparticles (CCC NPs) and evaluate their cell specificity as well as antibacterial activity against Escherichia coli in vitro. Methods. CCC NPs were prepared by ionic cross-linking method and optimized by using Box-Behnken response surface method (BBRSM). Zeta potential, drug encapsulation, and release of the obtained nanoparticles in vitro were thoroughly investigated. Minimum inhibitory concentration (MIC) and killing profiles of free or ciprofloxacin-loaded nanoparticles against Escherichia coli were documented. The cytotoicity of blank nanoparticles and cellular uptake of CCC NPs were also investigated. Results. The obtained particles were monodisperse nanospheres with an average hydrated diameter of 151?±?5.67?nm and surface of charge ?22.9?±?2.21?mV. The MICs of free ciprofloxacin and CCC NPs were 0.16 and 0.08??g/mL, respectively. Blank nanoparticles showed no obvious cell inhibition within 24?h, and noticeable phagocytosis effect was observed in the presence of CCC NPs. Conclusion. This study shows that CCC NPs have stronger antibacterial activity against Escherichia coli than the free ciprofloxacin because they can easily be uptaken by cells. The obtained CCC NPs have promising prospect in drug delivery field. PMID:23586023

Zhao, Liang; Zhu, Bingya; Jia, Yunhong; Hou, Wenjiu; Su, Chang

2013-01-01

413

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

414

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

415

Synthesis and investigation of magnetic properties of substituted ferrite nanoparticles of spinel system Mn 1-xZn x[Fe 2-yL y]O 4  

NASA Astrophysics Data System (ADS)

Superparamagnetic nanoparticles of the spinel ferrite four-element system Mn 1-xZn x[Fe 2-yL y]O 4 (where L:Gd 3+, La 3+, Ce 3+, Eu 3+, Dy 3+, Er 3+,Yb 3+) were synthesized by the co-precipitation method. The magnetic moments of the 10 nm diameter nanoparticles were comparable to the ones of Fe 3O 4 nanoparticles. A comparatively low TC (˜52-72 °C) was observed for some of the compositions. The heating mechanism of the superparamagnetic particles in the AC magnetic field at radiofrequency range is discussed and especially the absence of the hysteresis loop in the M-H curve at room temperature. One possible explanation—spontaneous particle agglomeration—was experimentally verified.

Brusentsova, Tatiana N.; Kuznetsov, Viatcheslav D.

2007-04-01

416

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

417

Cationic albumin nanoparticles for enhanced drug delivery to treat breast cancer: preparation and in vitro assessment.  

PubMed

Most anticancer drugs are greatly limited by the serious side effects that they cause. Doxorubicin (DOX) is an antineoplastic agent, commonly used against breast cancer. However, it may lead to irreversible cardiotoxicity, which could even result in congestive heart failure. In order to avoid these harmful side effects to the patients and to improve the therapeutic efficacy of doxorubicin, we developed DOX-loaded polyethylenimine- (PEI-) enhanced human serum albumin (HSA) nanoparticles. The formed nanoparticles were ~137?nm in size with a surface zeta potential of ~+15?mV, prepared using 20??g of PEI added per mg of HSA. Cytotoxicity was not observed with empty PEI-enhanced HSA nanoparticles, formed with low-molecular weight (25?kDa) PEI, indicating biocompatibility and safety of the nanoparticle formulation. Under optimized transfection conditions, approximately 80% of cells were transfected with HSA nanoparticles containing tetramethylrhodamine-conjugated bovine serum albumin. Conclusively, PEI-enhanced HSA nanoparticles show potential for developing into an effective carrier for anticancer drugs. PMID:22187654

Abbasi, Sana; Paul, Arghya; Shao, Wei; Prakash, Satya

2012-01-01

418

Preparation of porous polymer monoliths featuring enhanced surface coverage with gold nanoparticles.  

PubMed

A new approach to the preparation of porous polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40 nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60 wt% being achieved with 40 nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30 nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold. PMID:22542442

Lv, Yongqin; Alejandro, Fernando Maya; Fréchet, Jean M J; Svec, Frantisek

2012-10-26

419

Preparation and in vitro characterization of novel bioactive glass ceramic nanoparticles.  

PubMed

SiO(2)-CaO-P(2)O(5) ternary bioactive glass ceramic (BGC) nanoparticles with different compositions were prepared via a three-step sol-gel method. Polyethylene glycol was selected to be used as the surfactant to improve the dispersion of the nanoparticles. The morphology and composition of these BGC nanoparticles were observed by ESEM and EDX. All the BGC particles obtained in this method were about 20 nm in diameter. XRD analysis demonstrated that the different compositions can result in very different crystallinities for the BGC nanoparticles. Bioactivity tests in simulated body fluid solution (SBF), and degradability in phosphate buffer solution (PBS), were performed in vitro. SEM, EDX, and XRD were employed to monitor the surface variation of neat poly(L-lactic acid), PLLA, foam and PLLA/BGC porous scaffolds during incubation. The BGC nanoparticles with lower phosphorous and relative higher silicon content exhibited enhanced mineralization capability in SBF and a higher solubility in PBS medium. Such novel nanoparticles may have potential to be used in different biomedical applications, including tissue engineering or the orthopedic field. PMID:18286606

Hong, Zhongkui; Reis, Rui L; Mano, João F

2009-02-01

420

Photocatalytic activity of ZnO nanoparticles prepared via submerged arc discharge method  

NASA Astrophysics Data System (ADS)

ZnO nanostructures were synthesized through arc discharge of zinc electrodes in deionized (DI) water. X-ray diffraction (XRD) analysis of the prepared nanostructures indicates formation of crystalline ZnO of hexagonal lattice structures. Transmission electron microscopy (TEM) images illustrate rod-like as well as semi spherical ZnO nanoparticles with 15-20 nm diameter range, which were formed during the discharge process with 5 A arc current. The average particle size was found to increase with the increasing arc current. X-ray photoelectron spectroscopy (XPS) analysis confirms formation of ZnO at the surface of the nanoparticles. Surface area of the sample prepared at 5 A arc current, measured by BET analysis, was 34 m2/g. Photodegradation of Rhodamine B (Rh. B) shows that the prepared samples at lower currents have a higher photocatalytic activity due to larger surface area and smaller particle size.

Ashkarran, Ali Akbar; Iraji Zad, Azam; Mahdavi, Seyed Mohammad; Ahadian, Mohammad Mahdi

2010-09-01

421

Water-repellent coatings prepared by modification of ZnO nanoparticles.  

PubMed

Superhydrophobic coatings with a static water contact angle (WCA)>150° were prepared by modifying ZnO nanoparticles with stearic acid (ZnO@SA). ZnO nanoparticles of size ?14nm were prepared by solution combustion method. X-ray diffraction (XRD) studies reveal that as prepared ZnO has hexagonal wurtzite structure whereas the modified coatings convert to zinc stearate. Field emission scanning electron micrographs (FE-SEM) show the dual morphology of the coatings exhibiting both particles and flakes. The flakes are highly fluffy in nature with voids and nanopores. Fourier transformed infrared (FTIR) spectrum shows the stearate ion co-ordinates with Zn(2+) in the bidentate form. The surface properties such as surface free energy (?(p)) and work of adhesion (W) of the unmodified and modified ZnO coatings have been evaluated. The electron paramagnetic resonance (EPR) spectroscopy reveals that surface defects play a major role in the wetting behavior. PMID:22575349

Chakradhar, R P S; Dinesh Kumar, V

2012-08-01

422

Water-repellent coatings prepared by modification of ZnO nanoparticles  

NASA Astrophysics Data System (ADS)

Superhydrophobic coatings with a static water contact angle (WCA) > 150° were prepared by modifying ZnO nanoparticles with stearic acid (ZnO@SA). ZnO nanoparticles of size ˜14 nm were prepared by solution combustion method. X-ray diffraction (XRD) studies reveal that as prepared ZnO has hexagonal wurtzite structure whereas the modified coatings convert to zinc stearate. Field emission scanning electron micrographs (FE-SEM) show the dual morphology of the coatings exhibiting both particles and flakes. The flakes are highly fluffy in nature with voids and nanopores. Fourier transformed infrared (FTIR) spectrum shows the stearate ion co-ordinates with Zn2+ in the bidentate form. The surface properties such as surface free energy (?p) and work of adhesion (W) of the unmodified and modified ZnO coatings have been evaluated. The electron paramagnetic resonance (EPR) spectroscopy reveals that surface defects play a major role in the wetting behavior.

Chakradhar, R. P. S.; Dinesh Kumar, V.

423

Titanium dioxide nanoparticles prepared by laser pyrolysis: Synthesis and photocatalytic properties  

NASA Astrophysics Data System (ADS)

TiO 2 nanoparticles were synthesized via the laser pyrolysis of titanium tetrachloride-based gas-phase mixtures. In the obtained nanopowders, a mixture of anatase and rutile phases with mean particle size of about 14 nm was identified. Using the thermal heated laser nanopowders, mechanically stable films were produced by immobilizing titania nanopowders on glass substrates (the doctor blading method followed by compression). The photocatalytic activity of the prepared films was tested by the degradation of 4-chlorophenol in an aqueous solution under UV-illumination. By referring to known commercial samples (Degussa P25) similarly prepared, higher photocatalytic efficiency was found for the laser-prepared samples.

Figgemeier, E.; Kylberg, W.; Constable, E.; Scarisoreanu, M.; Alexandrescu, R.; Morjan, I.; Soare, I.; Birjega, R.; Popovici, E.; Fleaca, C.; Gavrila-Florescu, L.; Prodan, G.

2007-12-01

424

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

425

Facile and efficient preparation of anisotropic DNA-functionalized gold nanoparticles and their regioselective assembly  

PubMed Central

Anisotropic nanoparticles can provide considerable opportunities for assembly of nanomaterials with unique structures and properties. However, most reported anisotropic nanoparticles are either difficult to prepare, have a low yield, or difficult to functionalize. Here we report a facile one-step solution-based method to prepare anisotropic DNA-functionalized gold nanoparticles (a-DNA-AuNP) with 96% yield and with high DNA density (120 ± 20 strands on the gold hemisphere surface). The method is based on the competition between a thiolated hydrophilic DNA and a thiolated hydrophobic phospholipid and has been applied to prepare a-DNA-AuNP with different sizes of nanoparticles and a variety of DNA sequences. In addition, DNA strands on the a-DNA-AuNP can be exchanged with other DNA strands with a different sequence. The anisotropic nature of the a-DNA-AuNPs allows regioselective hetero- and homo-nuclear assembly with high monodispersity, as well as regioselective functionalization of two different DNA strands for more diverse applications. PMID:24148071

Tan, Li Huey; Xing, Hang; Chen, Hongyu; Lu, Yi

2014-01-01

426

The effect of annealing on phase evolution, microstructure and magnetic properties of Mn substituted CoFe2O4 nanoparticles  

NASA Astrophysics Data System (ADS)

Manganese substituted CoFe2O4 nanoparticles has been prepared by a simple evaporation method and auto combustion method. The role of annealing temperature on phase, particle size and morphology of Mn-Co ferrite nanoparticles were determined by X-ray diffraction, and transmission electron microscopy (TEM). The lowest size of particles (~3 nm) is obtained by auto combustion method. The annealing effect creates a vital change in magnetic properties which is studied by using vibrating sample magnetometer (VSM). These spinel ferrites are decomposed to ?-Fe2O3 after annealing above 550 °C in air. However, ?-Fe2O3 phase was slowly vanished after ferrites annealing above 900 °C. The effect of this secondary phase on the structural and magnetic properties of Mn substituted cobalt ferrite nanoparticles is also discussed.

Ranjith Kumar, E.; Jayaprakash, R.; Prakash, T.

2014-05-01

427

Size selected synthesis of CoFe2O4 nanoparticles prepared in a chitosan matrix  

NASA Astrophysics Data System (ADS)

In this paper we report the synthesis and magnetic properties of CoFe2O4 nanoparticles. The nanoparticles with sizes ranging from 6 to 20 nm were prepared in a chitosan matrix. Size selection was achieved by introducing a nonionic surfactant Tween-X, where X={20, 60, 80, and 85}. Aqueous dispersions of Tween-X show micelles with increasing hydrodynamic sizes as X increases. Mössbauer spectroscopy measurements at 300 K show superparamagnetic behavior for the small particles, changing gradually to a blocked magnetic regime as the particle size increases. Magnetization measurements at 300 K show increasing values for the ratio Mr/MHmax and coercive fields (Hc).

Gurgel, A. L.; Soares, J. M.; Chaves, D. S.; Chaves, D. S.; Xavier, M. M.; Morales, M. A.; Baggio-Saitovitch, E. M.

2010-05-01

428

Inorganic–organic hybrid polyoxometalate nanoparticle modified wax impregnated graphite electrode: preparation, electrochemistry and electrocatalysis  

Microsoft Academic Search

A kind of inorganic–organic hybrid polyoxometalate (POM) nanoparticle [(CH3)4N]6P2Mo18O62?·?9H2O has been designed and prepared by solid-state reaction at room temperature and immobilized on the surface of a wax impregnated graphite electrode (WIGE) by the sol–gel technique for the first time. The electrochemical behavior of the [(CH3)4N]6P2Mo18O62?·?9H2O nanoparticle modified WIGE (P2Mo18-WIGE) has been studied in detail, including pH-dependence, solvent effect and

Xiuli Wang; Zhenhui Kang; Enbo Wang; Changwen Hu

2002-01-01

429

Color and surface plasmon effects in nanoparticle systems: Case of silver nanoparticles prepared by microemulsion route  

Microsoft Academic Search

Surface plasmon resonance (SPR) in suspended metallic nanoparticles, like Ag, gives rise to fascinating colors that are different from those observed in bulk materials. Although these effects have been highlighted in many recent articles [1], [2], [3] and [4], no experimental study of color properties with respect to system parameters such as concentration and size of particles is available in

Anurag Mehra; Rochish Thaokar

2012-01-01

430

Preparation of polylysine-modified superparamagnetic iron oxide nanoparticles  

NASA Astrophysics Data System (ADS)

Polylysine (PLL) coated iron oxide nanoparticles (SPIONs) have potential in biomedical application. In the present work PEG coated SPIONs (PEG-SPIONs) with the particle size of 9.4±1.4 nm were synthesized by thermal decomposition of Fe(acac)3 in PEG, and then coated with PLL (PLL/PEG-SPIONs). The PEG-SPIONs and PLL/PEG-SPIONs were superparamagnetic with the saturation magnetization of 53 and 44 emu/g, respectively. The hydrodynamic diameter of PEG-SPIONs in deionized water was 18.8 nm, which increased to 21.3-28.2 nm after mixing with different amount of PLL. The zeta potentials of PLL/PEG-SPIONs were -8.9 - -3.4 mV which were changing with time. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that PLL was attached to the PEG-SPIONs.

Yang, Gao; Zhang, Baolin; Wang, Jun; Xie, Songbo; Li, Xuan

2015-01-01

431

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.

432

Preparation of tungsten carbide nanoparticles by ion implantation and electrochemical etching  

NASA Astrophysics Data System (ADS)

Glassy carbon (GC) substrates were implanted with 100 keV tungsten ions at retained fluences of 4 × 1016 and 6 × 1016 ions/cm2 and surface-etched electrochemically in order to prepare tungsten-carbide (WC) nanoparticles on their topmost layers. The calculated current efficiency for the electrochemical etching was nearly the same for the two samples implanted at different fluences, suggesting the controllability of the etched depth using the consumed electric charge. The etching front reached the buried tungsten-implanted layer and increased the tungsten concentration at the surface. No oxidation of WC was observed, even under anodic potential application during electrochemical etching. The voltammogram response of the topmost nanoparticle layer was too small to be observed, probably due to the limited activity of the WC itself and the remaining low concentration. It was demonstrated that this technique could, in principle, be applied to various types of nanoparticle catalysts implanted in GC substrates.

Kato, S.; Yamaki, T.; Yamamoto, S.; Hakoda, T.; Kawaguchi, K.; Kobayashi, T.; Suzuki, A.; Terai, T.

2013-11-01

433

Preparation, characterization and MRI application of carboxymethyl dextran coated magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Superparamagnetic nanoparticles functionalized with carboxymethyl dextran (CM-dextran) were synthesized by a two-step method. First, the magnetic nanoparticles (MNPs) coated with dextran ( Mw ? 20000) were prepared by co-precipitation of Fe 2+ and Fe 3+ ions. Then, dextran on the surface of MNPs reacted with monochloroacetic acid (MCA) in alkaline condition. The influences of temperature and reactant concentration on the amount of -COOH on the surface of nanoparticles were systematically studied. The obtained MNPs coated with CM-dextran were stable over the entire range of pH and NaCl concentration. The MRI experiment indicated that the CM-dextran MNPs could potentially be used as MRI contrast agents for magnetic resonance molecular imaging.

Liu, G.; Hong, R. Y.; Guo, L.; Li, Y. G.; Li, H. Z.

2011-05-01

434

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

435

An experimental assessment of toxic potential of nanoparticle preparation of heavy metals in streptozotocin induced diabetes.  

PubMed

Nanoparticle preparations of heavy metals have attracted enormous scientific and technological interest. Biologically produced nanoparticle preparations of heavy metals are elaborately described in traditional texts and being widely prescribed. The underlying interactions of nano preparations within the physiological fluids are key feature to understand their biological impact. In this perspective, we performed an experimental assessment of the toxicity potential of a marketed metallic preparation named Vasant Kusumakar Ras (VKR), wherein different heavy metals in composite form are reduced to nanoparticle size to produce the desired effect in diabetes and its complications. VKR (50mg/kg) was administered to Albino Wistar rats rendered diabetic using streptozotocin (90mg/kg) in 2 days old neonates. Anti-hyperglycemic effect was observed with VKR along with increased levels of plasma insulin. Renal variables including total proteins and albumin along with glomerular filtration rate were found to improve biochemically. The results were supplemented by effects on different inflammatory and growth factors like TNF-?, nitric oxide, TGF-? and VEGF. However, the results observed in kidney histopathology were not in accordance with the biochemical parameters. Inflammation observed in kidney was confirmed by immunostaining metallothionein, which was due to the accumulation of heavy metals. Furthermore, mercury accumulation in kidney further confirmed by autometallography, which activated mononuclear phagocyte system, which generated an immune response. This was further supported by increase in the extent of apoptosis in kidney tissues. In conclusion, nanoparticle preparations of heavy metals can be toxic to kidney if it is not regulated with respect to its surface chemistry and dosage. PMID:23790456

Gandhi, Sonia; Srinivasan, B P; Akarte, Atul Sureshrao

2013-11-01

436

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

437

Preparation and cytotoxicity comparison of type a gelatin nanoparticles with recombinant human gelatin nanoparticles  

Microsoft Academic Search

Gelatin nanoparticles derived from bovine or porcine have been developed as various types of drug delivery system, and they\\u000a need to be cross-linked to maintain their physicochemical properties in aqueous environments. Although gelatin is a widely\\u000a used material in pharmaceutical industries, the safety issue of animal-origin gelatins, such as transmissible mad cow disease\\u000a and anaphylaxis, remains to be solved. The

Young-Wook Won; Yong-Hee Kim

2009-01-01

438

The novel albumin–chitosan core–shell nanoparticles for gene delivery: preparation, optimization and cell uptake investigation  

PubMed Central

Natural polymers and proteins such as chitosan (CS) and albumin (Alb) have recently attracted much attention both in drug delivery and gene delivery. The underlying rationale is their unique properties such as biodegradability, biocompatibility and controlled release. This study aimed to prepare novel albumin–chitosan–DNA (Alb-CS-DNA) core–shell nanoparticles as a plasmid delivery system and find the best conditions for their preparation. Phase separation method and ionic interaction were used for preparation of Alb nanoparticles and Alb-CS-DNA core–shell nanoparticles, respectively. The effects of three important independent variables (1) CS/Alb mass ratio, (2) the ratios of moles of the amine groups of cationic polymers to those of the phosphate groups of DNA (N/P ratio), and (3) Alb concentration, on the nanoparticle size and loading efficiency of the plasmid were investigated and optimized through Box–Behnken design of response surface methodology (RSM). The optimum conditions were found to be CS/Alb mass ratio = 3, N/P ratio = 8.24 and Alb concentration = 0.1 mg/mL. The most critical factors for the size of nanoparticles and loading efficiency were Alb concentration and N/P ratio. The optimized nanoparticles had an average size of 176 ± 3.4 nm and loading efficiency of 80 ± 3.9 %. Cytotoxicity experiments demonstrated that the prepared nanoparticles were not toxic. The high cellular uptake of nanoparticles (~85 %) was shown by flow cytometry and fluorescent microscopy. PMID:24363607

Karimi, Mahdi; Avci, Pinar; Mobasseri, Rezvan; Hamblin, Michael R.

2013-01-01

439

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