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Sample records for ferrite nanoparticles prepared

  1. Magnetic studies of magnesium ferrite nanoparticles prepared by sol-gel technique

    SciTech Connect

    Argish, V.; Chithra, M.; Anumol, C. N.; Sahoo, S. C.; Sahu, B. N.

    2015-06-24

    Mg-ferrite nanoparticles were prepared by sol-gel technique and were annealed at different temperatures in air for 4 hours. Structural studies by X-ray diffraction confirmed the Mg-ferrite phasein all the samples annealed up to 600°C. Traces of α-Fe{sub 2}O{sub 3} were found for the sample annealed at higher temperature of 750°C.Grain size was found to be increasedfrom 13nm to 37nm with the increase in the annealing temperature. These samples showed super-paramagentic behavior at 300K where as at 60K they showed ferrimagnetic behavior.For the as prepared sample the magnetization value of 21emu/g was observed at 300K. The highest magnetization value of 24 emu/g which is ∼ 90% of the bulk value of Mg-ferrite, was observed at 300K for the sample annealed at 750°C.The observed magnetic behavior of these nanoparticles may be understood on the basis of nanosize grains, increase inrandom anisotropy and reduced thermal effects at low temperature.

  2. Preparation of silica coated cobalt ferrite magnetic nanoparticles for the purification of histidine-tagged proteins

    NASA Astrophysics Data System (ADS)

    Aygar, Gülfem; Kaya, Murat; Özkan, Necati; Kocabıyık, Semra; Volkan, Mürvet

    2015-12-01

    Surface modified cobalt ferrite (CoFe2O4) nanoparticles containing Ni-NTA affinity group were synthesized and used for the separation of histidine tag proteins from the complex matrices through the use of imidazole side chains of histidine molecules. Firstly, CoFe2O4 nanoparticles with a narrow size distribution were prepared in an aqueous solution using the controlled co-precipitation method. In order to obtain small CoFe2O4 agglomerates, oleic acid and sodium chloride were used as dispersants. The CoFe2O4 particles were coated with silica and subsequently the surface of these silica coated particles (SiO2-CoFe2O4) was modified by amine (NH2) groups in order to add further functional groups on the silica shell. Then, carboxyl (-COOH) functional groups were added to the SiO2-CoFe2O4 magnetic nanoparticles through the NH2 groups. After that Nα,Nα-Bis(carboxymethyl)-L-lysine hydrate (NTA) was attached to carboxyl ends of the structure. Finally, the surface modified nanoparticles were labeled with nickel (Ni) (II) ions. Furthermore, the modified SiO2-CoFe2O4 magnetic nanoparticles were utilized as a new system that allows purification of the N-terminal His-tagged recombinant small heat shock protein, Tpv-sHSP 14.3.

  3. Preparation of Magnesium, Cobalt and Nickel Ferrite Nanoparticles from Metal Oxides using Deep Eutectic Solvents.

    PubMed

    Söldner, Anika; Zach, Julia; Iwanow, Melanie; Gärtner, Tobias; Schlosser, Marc; Pfitzner, Arno; König, Burkhard

    2016-09-05

    Natural deep eutectic solvents (DESs) dissolve simple metal oxides and are used as a reaction medium to synthesize spinel-type ferrite nanoparticles MFe2 O4 (M=Mg, Zn, Co, Ni). The best results for phase-pure spinel ferrites are obtained with the DES consisting of choline chloride (ChCl) and maleic acid. By employing DESs, the reactions proceed at much lower temperatures than usual for the respective solid-phase reactions of the metal oxides and at the same temperatures as synthesis with comparable calcination processes using metal salts. The method therefore reduces the overall required energy for the nanoparticle synthesis. Thermogravimetric analysis shows that the thermolysis process of the eutectic melts in air occurs in one major step. The phase-pure spinel-type ferrite particles are thoroughly characterized by X-ray diffraction, diffuse-reflectance UV/Vis spectroscopy, and scanning electron microscopy. The properties of the obtained nanoparticles are shown to be comparable to those obtained by other methods, illustrating the potential of natural DESs for processing metal oxides.

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

    SciTech Connect

    Shirtcliffe, Neil J. . E-mail: neil.shirtcliffe@ntu.ac.uk; Thompson, Simon; O'Keefe, Eoin S.; Appleton, Steve; Perry, Carole C. . E-mail: carole.perry@ntu.ac.uk

    2007-02-15

    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.

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

    SciTech Connect

    Ma, Jie; Zhao, Jiantao; Li, Wenlie; Zhang, Shuping; Tian, Zhenran; Basov, Sergey

    2013-02-15

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

  6. Preparation of Mn-Zn ferrite nanoparticles and their silica-coated clusters: Magnetic properties and transverse relaxivity

    NASA Astrophysics Data System (ADS)

    Kaman, Ondřej; Kuličková, Jarmila; Herynek, Vít; Koktan, Jakub; Maryško, Miroslav; Dědourková, Tereza; Knížek, Karel; Jirák, Zdeněk

    2017-04-01

    Hydrothermal synthesis of Mn1-xZnxFe2O4 nanoparticles followed by direct encapsulation of the as-grown material into silica is demonstrated as a fast and facile method for preparation of efficient negative contrast agents based on clusters of ferrite crystallites. At first, the hydrothermal procedure is optimized to achieve strictly single-phase magnetic nanoparticles of Mn-Zn ferrites in the compositional range of x≈0.2-0.6 and with the mean size of crystallites ≈10 nm. The products are characterized by powder X-ray diffraction, X-ray fluorescence spectroscopy, and SQUID magnetometry, and the composition close to x=0.4 is selected for the preparation of silica-coated clusters with the mean diameter of magnetic cores ≈25 nm. Their composite structure is studied by means of transmission electron microscopy combined with detailed image analysis and magnetic measurements in DC fields. The relaxometric studies, performed in the magnetic field of B0=0.5 T, reveal high transverse relaxivity (r2(20 °C)=450 s-1 mmol(Me3O4)-1 L) with a pronounced temperature dependence, which correlates with the observed temperature dependence of magnetization and is ascribed to a mechanism of transverse relaxation similar to the motional averaging regime.

  7. Preparation of magnesium ferrite nanoparticles by ultrasonic wave-assisted aqueous solution ball milling.

    PubMed

    Chen, Ding; Li, Dian-yi; Zhang, Ying-zhe; Kang, Zhi-tao

    2013-11-01

    Magnesium ferrite, MgFe2O4 nanoparticles with high saturation magnetization were successfully synthesized using ultrasonic wave-assisted ball milling. In this study, the raw materials were 4MgCO3·Mg(OH)2·5H2O and Fe2O3 powders and the grinding media was stainless steel ball. The average particle diameter of the product MgFe2O4 powders was 20 nm and the saturation magnetization of them reached 54.8 emu/g. The different results of aqueous solution ball milling with and without ultrasonic wave revealed that it was the coupling effect of ultrasonic wave and mechanical force that played an important role during the synthesis of MgFe2O4. In addition, the effect of the frequency of the ultrasonic wave on the ball milling process was investigated.

  8. 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

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

    2010-12-02

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    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.

  10. Magnetic Characterization of Ferrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Bryan, Matthew; Sokol, Paul; Gumina, Greg; Bronstein, Lyudmila; Dragnea, Bogdan

    2011-03-01

    Magnetic nanoparticles (NPs) of different compositions (FeO/ Fe 3 O4 , g- Fe 2 O3 , FePt, and CoFe 2 O4) have been synthesized using high temperature organometallic routes described elsewhere. NPs (16.6 nm in diameter) of a mixed FeO/ Fe 3 O4 (wuestite/magnetite) composition were prepared by thermal decomposition or iron oleate in the presence of oleic acid as a surfactant in dodocane at 370C in argon atmosphere. After the thermal treatment of the reaction solution at 200 C under air for 2 hours these NPs are transformed into maghemite (g- Fe 2 O3) , the magnetization of which is significantly enhanced. NPs of CoFe 2 O4 (8 nm) have been prepared by simultaneous decomposition of Co(II) and Fe(III) acetylacetonates in the presence of oleic acid and oleylamine. The X-ray diffraction profile of these NPs is characteristic of cobalt ferrite. Alternatively, alloyed 1.8 nm FePt NPs prepared by simultaneous decomposition of Fe and Pt acetylacetonates in the reductive environment demonstrate a completely disordered structure, which is reflected in their magnetic properties. SQUID magnetometry was used to measure the magnetization of NPs at high and low temperatures. Zero-field cooling and field-cooling measurements were taken to demonstrate superparamagnetic behavior and an associated blocking temperature.

  11. Preparation of spherical and uniform-sized ferrite nanoparticles with diameters between 50 and 150 nm for biomedical applications

    NASA Astrophysics Data System (ADS)

    Tanaka, Toshiyuki; Shimazu, Ryuichi; Nagai, Hironori; Tada, Masaru; Nakagawa, Takashi; Sandhu, Adarsh; Handa, Hiroshi; Abe, Masanori

    2009-05-01

    Spherical uniform-sized iron ferrite nanoparticles were synthesized by adding a disaccharide and seed ferrite crystals into an aqueous reaction solution. The average size range 50-150 nm was controlled by choosing one out of five disaccharides and by changing the amount of the seed crystals. The particles had a saturation magnetization and a crystalline structure which are similar to those of intermediate Fe 3O 4-γ-Fe 2O 3. When coated with citrate, the particles with nearly 100 nm diameter were stably suspended in water for 2 days. These novel particles will be utilized as magnetic carriers in biomedical applications.

  12. Comparison of nanostructured nickel zinc ferrite and magnesium copper zinc ferrite prepared by water-in-oil microemulsion

    NASA Astrophysics Data System (ADS)

    Hee, Ay Ching; Mehrali, Mehdi; Metselaar, Hendrik Simon Cornelis; Mehrali, Mohammad; Osman, Noor Azuan Abu

    2012-12-01

    Ferrite is an important ceramic material with magnetic properties that are useful in many types of electronic devices. In this study, structure and magnetic properties of nanostructured nickel zinc ferrite and magnesium copper zinc ferrite prepared by water-in-oil microemulsion were compared. Both ferrites samples demonstrated similar weight loss characteristics in TGA. The magnesium copper zinc ferrite showed a crystalline structure with an average crystallite size of 13.5 nm. However, nickel zinc ferrite showed an amorphous phase. Transmission electron micrographs showed agglomerated nanoparticles with an average crystallite size of 26.6 nm for magnesium copper zinc ferrite and 22.7 nm for nickel zinc ferrite. Magnesium copper zinc ferrite exhibited soft ferromagnetic bahaviour whereas nickel zinc ferrite showed superparamagnetic nature.

  13. Effects of the synthesis temperature on the crystalline structure and the magnetic properties of cobalt ferrite nanoparticles prepared via coprecipitation

    NASA Astrophysics Data System (ADS)

    Hutamaningtyas, Evangelin; Utari; Suharyana; Purnama, Budi; Wijayanta, Agung Tri

    2016-08-01

    The effects of the synthesis temperature on the crystalline structure and the magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared via coprecipitation are discussed. The synthesis was conducted at temperatures of 75 °C, 85 °C and 95 °C. Fourier transform infrared spectroscopy characterization related to a stretching vibration at a wavenumber of 590 cm-1 indicated the formation of a CoFe2O4 metal oxide. In addition, powder X ray diffraction (XRD) characterization proved that the metal oxide was CoFe2O4. Crystallite sizes calculated using the Scherer formula at the strongest peak of the XRD spectra of the samples synthesized at 75 °C, 85 °C and 95 °C were 32 nm, 43 nm and 50.4 nm, respectively. Finally, the results of the vibrating sample magnetometer characterization showed that the saturation magnetization decreased with increasing synthesis temperature, which is related to the dominant preference of Co2+ over Fe3+ cations at the octahedral sites.

  14. Spin canting in ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Marx, J.; Huang, H.; Salih, K. S. M.; Thiel, W. R.; Schünemann, V.

    2016-12-01

    Recently, an easily scalable process for the production of small (3 -7 nm) monodisperse superparamagnetic ferrite nanoparticles MeFe2O4 (Me = Zn, Mn, Co) from iron metal and octanoic acid has been reported (Salih et al., Chem. Mater. 25 1430-1435 2013). Here we present a Mössbauer spectroscopic study of these ferrite nanoparticles in external magnetic fields of up to B = 5 T at liquid helium temperatures. Our analysis shows that all three systems show a comparable inversion degree and the cationic distribution for the tetrahedral A and the octahedral B sites has been determined to (Zn0.19Fe0.81) A [Zn0.81Fe1.19] B O4, (Mn0.15Fe0.85) A [Mn0.85Fe1.15] B O4 and (Co0.27Fe0.73) A [Co0.73Fe1.27] B O4. Spin canting occurs presumably in the B-sites and spin canting angles of 33°, 51° and 59° have been determined for the zinc, the manganese, and the cobalt ferrite nanoparticles.

  15. Ferrite Nanoparticles in Pharmacological Modulation of Angiogenesis

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  16. Effect of bismuth doping on the structural and magnetic properties of zinc-ferrite nanoparticles prepared by a microwave combustion method

    NASA Astrophysics Data System (ADS)

    Shoushtari, Morteza Zargar; Emami, Akram; Ghahfarokhi, Seyed Ebrahim Mosavi

    2016-12-01

    In this study, we examine the bismuth doping effect on the structural, magnetic and microstructural properties of zinc-ferrite nanoparticles (ZnFe2-xBixO4 with x=0.0, 0.02, 0.04, 0.06, 0.1, 0.15) which have been prepared by a microwave combustion method. The structural, morphological and electromagnetic properties and also Curie temperature of the samples were examined by x-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), vibrating sample magnetometer (VSM), and LCR meter, respectively. In order to measure the energy band gap, the FTIR spectra of the samples were also considered. The XRD patterns of the samples revealed that all of them are ZnFe2O4 structure and no additional peak was observed in their patterns. This implied that the samples were single-phase up to bismuth solubility of 0.15 in Zinc-Ferrite. The results of XRD patterns also showed that the value lattice parameter increases with increasing the bismuth doping. The FESEM results revealed an ascending trend in the size of the nanoparticles. Also considering the VSM results characterized that an increasing the bismuth doping leads to lower the saturation magnetization. The Curie temperatures of the samples were reduced as a result of increasing the amount of bismuth.

  17. Study of DNA interaction with cobalt ferrite nanoparticles.

    PubMed

    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

    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.

  18. Strong and moldable cellulose magnets with high ferrite nanoparticle content.

    PubMed

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

    2014-11-26

    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.

  19. Chemical and physical characterizations of spinel ferrite nanoparticles containing Nd and B elements.

    PubMed

    Iwamoto, Takashi; Komorida, Yuki; Mito, Masaki; Takahara, Atsushi

    2010-05-15

    We first succeeded in synthesizing ferrite nanoparticles containing Nd and B elements by a chemical route using a polyol process. The lattice constants of the ferrite nanoparticles were equivalent to 8.39Å of the lattice constant for Fe(3)O(4) with the spinel structure in a bulk state independently of the size in diameter and composition (Fe:Nd:B). The size in diameter was actually dominated by the amount of ligands (oleic acid and oleylamine) coating the nanoparticles and easily tuned by changing refluxing-time under reaction. The spinel-structured ferrite nanoparticles containing Nd and B elements showed large coercivity as compared to Fe(3)O(4) nanoparticles with the spinel structure, which were prepared by the same chemical method. By doping Nd and B elements into the spinel structure of ferrite, magnetic anisotropy increased in comparison with Fe(3)O(4) nanoparticles. According to the analysis of magnetization curve using the modified Langevin function, the ferrite nanoparticles displayed the coexistence of superparamagnetic and antiferromagnetic phases. The ferrite nanoparticles containing Nd and B elements exhibited magnetic core/shell structure on the basis of various magnetic properties. The interface effect between the superparamagnetic core and antiferromagnetic shell might enhance the effective magnetic anisotropy of the ferrite nanoparticles containing Nd and B elements.

  20. Magnetoabsorption and magnetic hysteresis in Ni ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  1. Structural, Optical and Magnetic Properties of Ni-Zn Ferrite Nanoparticles Prepared by a Microwave Assisted Combustion Method.

    PubMed

    Vijaya, J Judith; Bououdina, M

    2016-01-01

    Ni-doped ZnFe₂O₄(Ni(x)Zn₁₋xFe₂O₄; x = 0.0 to 0.5) nanoparticles were synthesized by a simple microwave combustion method. The X-ray diffraction confirms the presence of cubic spinel ZnFe₂O₄for all compositions. The lattice parameter decreases with an increase in Ni content resulting in the reduction of lattice strain. High resolution scanning electron microscope images revealed that the as-prepared samples are crystalline with particle size distribution in 40-50 nm range. Optical properties were determined by UV-Visible diffuse reflectance and photoluminescence spectroscopy respectively. The saturation magnetization (Ms) shows the super paramagnetic nature of the sample for x = 0.0-0.2, whereas for x = 0.3-0.5, it shows ferromagnetic nature. The Ms value is 1.638 emu/g for pure ZnFe₂O₄ sample and it increases with increase in Ni content.

  2. Microwave-assisted synthesis and characterization of nickel ferrite nanoparticles

    SciTech Connect

    Carpenter, Gopal; Sen, Ravindra; Gupta, Nitish; Malviya, Nitin

    2015-08-28

    Nickel ferrite nanoparticles (NiFe{sub 2}O{sub 4}) were successfully prepared by microwave-assisted combustion method (MWAC) using citric Electron acid as a chelating agent. NiFe{sub 2}O{sub 4} nanoparticles were characterized by X-ray diffraction (XRD) pattern, Scanning Microscopy (SEM), Fourier transform infrared (FTIR) and UV-Visible techniques. XRD analysis revealed that NiFe{sub 2}O{sub 4} nanoparticles have spinel cubic structure with the average crystalline size of 26.38 nm. SEM analysis revealed random and porous structural morphology of particles and FTIR showed absorption bands related to octahedral and tetrahedral sites, in the range 400–600cm{sup −1} which strongly favor the formation of NiFe{sub 2}O{sub 4} nanoparticles. The optical band gap is determined by UV Visible method and found to be 5.4 eV.

  3. Microwave-assisted synthesis and characterization of nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Carpenter, Gopal; Sen, Ravindra; Malviya, Nitin; Gupta, Nitish

    2015-08-01

    Nickel ferrite nanoparticles (NiFe2O4) were successfully prepared by microwave-assisted combustion method (MWAC) using citric Electron acid as a chelating agent. NiFe2O4 nanoparticles were characterized by X-ray diffraction (XRD) pattern, Scanning Microscopy (SEM), Fourier transform infrared (FTIR) and UV-Visible techniques. XRD analysis revealed that NiFe2O4 nanoparticles have spinel cubic structure with the average crystalline size of 26.38 nm. SEM analysis revealed random and porous structural morphology of particles and FTIR showed absorption bands related to octahedral and tetrahedral sites, in the range 400-600cm-1 which strongly favor the formation of NiFe2O4 nanoparticles. The optical band gap is determined by UV Visible method and found to be 5.4 eV.

  4. Cobalt ferrite nanoparticles under high pressure

    SciTech Connect

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V.; Errandonea, D.

    2015-08-21

    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  5. Superparamagnetic calcium ferrite nanoparticles synthesized using a simple sol-gel method for targeted drug delivery.

    PubMed

    Sulaiman, N H; Ghazali, M J; Majlis, B Y; Yunas, J; Razali, M

    2015-01-01

    The calcium ferrite nano-particles (CaFe2O4 NPs) were synthesized using a sol-gel method for targeted drug delivery application. The proposed nano-particles were initially prepared by mixing calcium and iron nitrates that were added with citric acid in order to prevent agglomeration and subsequently calcined at a temperature of 550°C to obtain small particle size. The prepared nanoparticles were characterized by using an XRD (X-ray diffraction), which revealed the configuration of orthorhombic structures of the CaFe2O4 nano-particles. A crystallite size of ~13.59 nm was obtained using a Scherer's formula. Magnetic analysis using a VSM (Vibrating Sample Magnetometer analysis), revealed that the synthesized particles exhibited super-paramagnetic behavior having magnetization saturation of approximately 88.3emu/g. Detailed observation via the scanning electron microscopy (SEM) showed the calcium ferrite nano-particles were spherical in shape.

  6. Copper ferrite nanoparticle-induced cytotoxicity and oxidative stress in human breast cancer MCF-7 cells.

    PubMed

    Ahamed, Maqusood; Akhtar, Mohd Javed; Alhadlaq, Hisham A; Alshamsan, Aws

    2016-06-01

    Copper ferrite (CuFe2O4) nanoparticles (NPs) are important magnetic materials currently under research due to their applicability in nanomedicine. However, information concerning the biological interaction of copper ferrite NPs is largely lacking. In this study, we investigated the cellular response of copper ferrite NPs in human breast cancer (MCF-7) cells. Copper ferrite NPs were prepared by co-precipitation technique with the thermal effect. Prepared NPs were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and dynamic light scattering (DLS). Characterization data showed that copper ferrite NPs were crystalline, spherical with smooth surfaces and average diameter of 15nm. Biochemical studies showed that copper ferrite NPs induce cell viability reduction and membrane damage in MCF-7 cells and degree of induction was dose- and time-dependent. High SubG1 cell population during cell cycle progression and MMP loss with a concomitant up-regulation of caspase-3 and caspase-9 genes suggested that copper ferrite NP-induced cell death through mitochondrial pathway. Copper ferrite NP was also found to induce oxidative stress in MCF-7 cells as indicated by reactive oxygen species (ROS) generation and glutathione depletion. Cytotoxicity due to copper ferrite NPs exposure was effectively abrogated by N-acetyl-cysteine (ROS scavenger) suggesting that oxidative stress could be the plausible mechanism of copper ferrite NPs toxicity. Further studies are underway to explore the toxicity mechanisms of copper ferrite NPs in different types of human cells. This study warrants further generation of extensive biointeraction data before their application in nanomedicine.

  7. Biocompatibility of transition metal-substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Sanpo, Noppakun; Tharajak, Jirasak; Li, Yuncang; Berndt, Christopher C.; Wen, Cuie; Wang, James

    2014-07-01

    Transition metals of copper, zinc, manganese, and nickel were substituted into cobalt ferrite nanoparticles via a sol-gel route using citric acid as a chelating agent. The microstructure and elemental compositions of the nanoparticles were characterized using scanning electron microscopy combined with energy dispersive X-ray spectroscopy. The particle size of the nanoparticles was investigated using particle size analyzer, and the zeta potentials were measured using zeta potential analyzer. The phase components of the synthesized transition metal-substituted cobalt ferrite nanoparticles were studied using Raman spectroscopy. The biocompatibility of the nanoparticles was assessed using osteoblast-like cells. Results indicated that the substitution of transition metals strongly influences the physical, chemical properties, and biocompatibility of the cobalt ferrite nanoparticles.

  8. A facile microwave synthetic route for ferrite nanoparticles with direct impact in magnetic particle hyperthermia.

    PubMed

    Makridis, A; Chatzitheodorou, I; Topouridou, K; Yavropoulou, M P; Angelakeris, M; Dendrinou-Samara, C

    2016-06-01

    The application of ferrite magnetic nanoparticles (MNPs) in medicine finds its rapidly developing emphasis on heating mediators for magnetic hyperthermia, the ever-promising "fourth leg" of cancer treatment. Usage of MNPs depends largely on the preparation processes to select optimal conditions and effective routes to finely tailor MNPs. Microwave heating, instead of conventional heating offers nanocrystals at significantly enhanced rate and yield. In this work, a facile mass-production microwave hydrothermal synthetic approach was used to synthesize stable ferromagnetic manganese and cobalt ferrite nanoparticles with sizes smaller than 14 nm from metal acetylacetonates in the presence of octadecylamine. Prolonging the reaction time from 15 to 60 min, led to ferrites with improved crystallinity while the sizes are slight increased. The high crystallinity magnetic nanoparticles showed exceptional magnetic heating parameters. In vitro application was performed using the human osteosarcoma cell line Saos-2 incubated with manganese ferrite nanoparticles. Hyperthermia applied in a two cycle process, while AC magnetic field remained on until the upper limit of 45 °C was achieved. The comparative results of the AC hyperthermia efficiency of ferrite nanoparticles in combination with the in vitro study coincide with the magnetic features and their tunability may be further exploited for AC magnetic hyperthermia driven applications.

  9. Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Debnath, A.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

    2016-05-01

    Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl3) and Calcium chloride dihydrate (CaCl2.2H2O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

  10. Differential cytotoxicity of copper ferrite nanoparticles in different human cells.

    PubMed

    Ahmad, Javed; Alhadlaq, Hisham A; Alshamsan, Aws; Siddiqui, Maqsood A; Saquib, Quaiser; Khan, Shams T; Wahab, Rizwan; Al-Khedhairy, Abdulaziz A; Musarrat, Javed; Akhtar, Mohd Javed; Ahamed, Maqusood

    2016-10-01

    Copper ferrite nanoparticles (NPs) have the potential to be applied in biomedical fields such as cell labeling and hyperthermia. However, there is a lack of information concerning the toxicity of copper ferrite NPs. We explored the cytotoxic potential of copper ferrite NPs in human lung (A549) and liver (HepG2) cells. Copper ferrite NPs were crystalline and almost spherically shaped with an average diameter of 35 nm. Copper ferrite NPs induced dose-dependent cytotoxicity in both types of cells, evident by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide and neutral red uptake assays. However, we observed a quite different susceptibility in the two kinds of cells regarding toxicity of copper ferrite NPs. Particularly, A549 cells showed higher susceptibility against copper ferrite NP exposure than those of HepG2 cells. Loss of mitochondrial membrane potential due to copper ferrite NP exposure was observed. The mRNA level as well as activity of caspase-3 enzyme was higher in cells exposed to copper ferrite NPs. Cellular redox status was disturbed as indicated by induction of reactive oxygen species (oxidant) generation and depletion of the glutathione (antioxidant) level. Moreover, cytotoxicity induced by copper ferrite NPs was efficiently prevented by N-acetylcysteine treatment, which suggests that reactive oxygen species generation might be one of the possible mechanisms of cytotoxicity caused by copper ferrite NPs. To the best of our knowledge, this is the first report showing the cytotoxic potential of copper ferrite NPs in human cells. This study warrants further investigation to explore the mechanisms of differential toxicity of copper ferrite NPs in different types of cells. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Tuning the magnetism of ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Viñas, S. Liébana; Simeonidis, K.; Li, Z.-A.; Ma, Z.; Myrovali, E.; Makridis, A.; Sakellari, D.; Angelakeris, M.; Wiedwald, U.; Spasova, M.; Farle, M.

    2016-10-01

    The importance of magnetic interactions within an individual nanoparticle or between adjacent ones is crucial not only for the macroscopic collective magnetic behavior but for the AC magnetic heating efficiency as well. On this concept, single-(MFe2O4 where M=Fe, Co, Mn) and core-shell ferrite nanoparticles consisting of a magnetically softer (MnFe2O4) or magnetically harder (CoFe2O4) core and a magnetite (Fe3O4) shell with an overall size in the 10 nm range were synthesized and studied for their magnetic particle hyperthermia efficiency. Magnetic measurements indicate that the coating of the hard magnetic phase (CoFe2O4) by Fe3O4 provides a significant enhancement of hysteresis losses over the corresponding single-phase counterpart response, and thus results in a multiplication of the magnetic hyperthermia efficiency opening a novel pathway for high-performance, magnetic hyperthermia agents. At the same time, the existence of a biocompatible Fe3O4 outer shell, toxicologically renders these systems similar to iron-oxide ones with significantly milder side-effects.

  12. Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications.

    PubMed

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

    2013-03-01

    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.

  13. Mn-ferrite nanoparticles via reverse microemulsions: synthesis and characterization

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

    Mn-ferrite nanoparticles were synthesized by thermal treatment at 800 °C of manganese and iron oxo-hydroxides obtained via water-in-oil microemulsions consisting of n-hexanol as continuous phase, cetyl trimethyl ammonium bromide (CTAB) as the cationic surfactant and aqueous solutions of metal salts and precipitant agent (tetramethyl ammonium hydroxide) as reagents. Nanoparticles were synthesized using a multi-microemulsion approach. Two different co-precipitation routes are described depending on the Fe(II) or Fe(III) precursor salts. The influence of salt concentration and digestion process on the final products was examined. The nanoparticles were characterized by X-ray diffraction accompanied by Rietveld analysis, transmission electron microscopy, thermal analysis, infrared spectroscopy, and SQUID magnetometry. In all the synthesis reported in this study MnFe2O4 was observed only after thermal treatment at 800 °C of the as-prepared precursors. Almost spherical nanocrystalline MnFe2O4 ranging from 12 to 39 nm was obtained starting from chlorides or mixed chloride-sulfate salts as precursors. Low values of reduced remanent magnetization ( M r/ M s) and coercive field ( H c) induce to believe that a fraction of superparamagnetic particle is present at room temperature.

  14. Ferrite Nanoparticles, Films, Single Crystals, and Metamaterials: High Frequency Applications

    SciTech Connect

    Harris,V.

    2006-01-01

    Ferrite materials have long played an important role in power conditioning, conversion, and generation across a wide spectrum of frequencies (up to ten decades). They remain the preferred magnetic materials, having suitably low losses, for most applications above 1 MHz, and are the only viable materials for nonreciprocal magnetic microwave and millimeter-wave devices (including tunable filters, isolators, phase shifters, and circulators). Recently, novel processing techniques have led to a resurgence of research interest in the design and processing of ferrite materials as nanoparticles, films, single crystals, and metamaterials. These latest developments have set the stage for their use in emerging technologies that include cancer remediation therapies such as magnetohyperthermia, magnetic targeted drug delivery, and magneto-rheological fluids, as well as enhanced magnetic resonance imaging. With reduced dimensionality of nanoparticles and films, and the inherent nonequilibrium nature of many processing schemes, changes in local chemistry and structure have profound effects on the functional properties and performance of ferrites. In this lecture, we will explore these effects upon the fundamental magnetic and electronic properties of ferrites. Density functional theory will be applied to predict the properties of these ferrites, with synchrotron radiation techniques used to elucidate the chemical and structural short-range order. This approach will be extended to study the atomic design of ferrites by alternating target laser-ablation deposition. Recently, this approach has been shown to produce ferrites that offer attractive properties not found in conventionally grown ferrites. We will explore the latest research developments involving ferrites as related to microwave and millimeter-wave applications and the attempt to integrate these materials with semiconductor materials platforms.

  15. The role of cobalt ferrite magnetic nanoparticles in medical science.

    PubMed

    Amiri, S; Shokrollahi, H

    2013-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Rathod, Sopan M.; Shinde, Ashok B.

    2012-11-01

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

  17. Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin

    PubMed Central

    Volatron, Jeanne; Kolosnjaj-Tabi, Jelena; Javed, Yasir; Vuong, Quoc Lam; Gossuin, Yves; Neveu, Sophie; Luciani, Nathalie; Hémadi, Miryana; Carn, Florent; Alloyeau, Damien; Gazeau, Florence

    2017-01-01

    Metallic nanoparticles have been increasingly suggested as prospective therapeutic nanoplatforms, yet their long-term fate and cellular processing in the body is poorly understood. Here we examined the role of an endogenous iron storage protein – namely the ferritin – in the remediation of biodegradable cobalt ferrite magnetic nanoparticles. Structural and elemental analysis of ferritins close to exogenous nanoparticles within spleens and livers of mice injected in vivo with cobalt ferrite nanoparticles, suggests the intracellular transfer of degradation-derived cobalt and iron, entrapped within endogenous protein cages. In addition, the capacity of ferritin cages to accommodate and store the degradation products of cobalt ferrite nanoparticles was investigated in vitro in the acidic environment mimicking the physiological conditions that are present within the lysosomes. The magnetic, colloidal and structural follow-up of nanoparticles and proteins in the lysosome-like medium confirmed the efficient remediation of nanoparticle-released cobalt and iron ions by ferritins in solution. Metal transfer into ferritins could represent a quintessential process in which biomolecules and homeostasis regulate the local degradation of nanoparticles and recycle their by-products. PMID:28067263

  18. Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin

    NASA Astrophysics Data System (ADS)

    Volatron, Jeanne; Kolosnjaj-Tabi, Jelena; Javed, Yasir; Vuong, Quoc Lam; Gossuin, Yves; Neveu, Sophie; Luciani, Nathalie; Hémadi, Miryana; Carn, Florent; Alloyeau, Damien; Gazeau, Florence

    2017-01-01

    Metallic nanoparticles have been increasingly suggested as prospective therapeutic nanoplatforms, yet their long-term fate and cellular processing in the body is poorly understood. Here we examined the role of an endogenous iron storage protein – namely the ferritin – in the remediation of biodegradable cobalt ferrite magnetic nanoparticles. Structural and elemental analysis of ferritins close to exogenous nanoparticles within spleens and livers of mice injected in vivo with cobalt ferrite nanoparticles, suggests the intracellular transfer of degradation-derived cobalt and iron, entrapped within endogenous protein cages. In addition, the capacity of ferritin cages to accommodate and store the degradation products of cobalt ferrite nanoparticles was investigated in vitro in the acidic environment mimicking the physiological conditions that are present within the lysosomes. The magnetic, colloidal and structural follow-up of nanoparticles and proteins in the lysosome-like medium confirmed the efficient remediation of nanoparticle-released cobalt and iron ions by ferritins in solution. Metal transfer into ferritins could represent a quintessential process in which biomolecules and homeostasis regulate the local degradation of nanoparticles and recycle their by-products.

  19. Physiological Remediation of Cobalt Ferrite Nanoparticles by Ferritin.

    PubMed

    Volatron, Jeanne; Kolosnjaj-Tabi, Jelena; Javed, Yasir; Vuong, Quoc Lam; Gossuin, Yves; Neveu, Sophie; Luciani, Nathalie; Hémadi, Miryana; Carn, Florent; Alloyeau, Damien; Gazeau, Florence

    2017-01-09

    Metallic nanoparticles have been increasingly suggested as prospective therapeutic nanoplatforms, yet their long-term fate and cellular processing in the body is poorly understood. Here we examined the role of an endogenous iron storage protein - namely the ferritin - in the remediation of biodegradable cobalt ferrite magnetic nanoparticles. Structural and elemental analysis of ferritins close to exogenous nanoparticles within spleens and livers of mice injected in vivo with cobalt ferrite nanoparticles, suggests the intracellular transfer of degradation-derived cobalt and iron, entrapped within endogenous protein cages. In addition, the capacity of ferritin cages to accommodate and store the degradation products of cobalt ferrite nanoparticles was investigated in vitro in the acidic environment mimicking the physiological conditions that are present within the lysosomes. The magnetic, colloidal and structural follow-up of nanoparticles and proteins in the lysosome-like medium confirmed the efficient remediation of nanoparticle-released cobalt and iron ions by ferritins in solution. Metal transfer into ferritins could represent a quintessential process in which biomolecules and homeostasis regulate the local degradation of nanoparticles and recycle their by-products.

  20. Corrosion behavior of magnetic ferrite coating prepared by plasma spraying

    SciTech Connect

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

    2014-12-15

    Graphical abstract: The saturation magnetization (M{sub s}) of the ferrite coating is 34.417 emu/g while the M{sub s} value of the ferrite powder is 71.916 emu/g. It can be seen that plasma spray process causes deterioration of the room temperature soft magnetic properties. - Highlights: • Spinel ferrite coatings have been prepared by plasma spraying. • The coating consists of nanocrystalline grains. • The saturation magnetization of the ferrite coating is 34.417 emu/g. • Corrosion behavior of the ferrite coating was examined in NaCl solution. - Abstract: In this study, spray dried spinel ferrite powders were deposited on the surface of mild steel substrate through plasma spraying. The structure and morphological studies on the ferrite coatings were carried out using X-ray diffraction, scanning electron microscope and Raman spectroscopy. It was showed that spray dried process was an effective method to prepare thermal spraying powders. The coating showed spinel structure with a second phase of LaFeO{sub 3}. The magnetic property of the ferrite samples were measured by vibrating sample magnetometer. The saturation magnetization (M{sub s}) of the ferrite coating was 34.417 emu/g. The corrosion behavior of coating samples was examined by electrochemical impedance spectroscopy. EIS diagrams showed three corrosion processes as the coating immersed in 3.5 wt.% NaCl solution. The results suggested that plasma spraying was a promising technology for the production of magnetic ferrite coatings.

  1. Synthesis, characterization and potential application of MnZn ferrite and MnZn ferrite @ Au nanoparticles.

    PubMed

    Wang, Xin; Wang, Lingyan; Lim, I-Im S; Bao, Kun; Mott, Derrick; Park, Hye-Young; Luo, Jin; Hao, Shunli; Zhong, Chuan-Jian

    2009-05-01

    The ability to tune the magnetic properties of magnetic nanoparticles by manipulating the composition or surface properties of the nanoparticles is important for exploiting the application of the nanomaterials. This report describes preliminary findings of an investigation of the viability of synthesizing MnZn ferrite and core @ shell MnZn ferrite @ Au nanoparticles as potentially magnetization-tunable nanomaterials. The synthesis of the core-shell magnetic nanoparticles involved a simple combination of seed formation of the MnZn ferrite magnetic nanoparticles and surface coating of the seeds with gold shells. Water-soluble MnZn ferrite nanoparticles of 20-40 nm diameters and MnZn ferrite @ Au nanoparticles of 30-60 nm have been obtained. The MnZn ferrite @ Au nanoparticles have been demonstrated to be viable in magnetic separation of nanoparticles via interparticle antibody-specific binding reactivity between antibodies on the gold shells of the core-shell magnetic particles and proteins on gold nanoparticles. These findings have significant implications to the design of the core @ shell magnetic nanomaterials with core composition tuned magnetization for bioassay application.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

  4. Facile method to synthesize dopamine-capped mixed ferrite nanoparticles and their peroxidase-like activity

    NASA Astrophysics Data System (ADS)

    Mumtaz, Shazia; Wang, Li-Sheng; Abdullah, Muhammad; Zajif Hussain, Syed; Iqbal, Zafar; Rotello, Vincent M.; Hussain, Irshad

    2017-03-01

    A facile single-step strategy to prepare stable and water-dispersible dopamine-functionalized ultra-small mixed ferrite nanoparticles MFe2O4-DOPA (where M is a bivalent metal atom i.e. Fe, Co Cu, Mn and Ni) at room temperature is described. The nanoparticles formed have narrow size distribution as indicated by their characterization using transmission electron microscopy (TEM) and dynamic light scattering. The surface chemistry of these nanoparticles was probed by FTIR spectroscopy indicating their successful capping with dopamine ligands, which was further confirmed using zetapotential measurements and thermogravimetric analysis. The comparative horseradish peroxidase (HRP)—like activity of these cationic mixed ferrites nanoparticles was studied at pH 4.6 using a negatively-charged 2, 2‧-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) as a chromogenic substrate in the presence of hydrogen peroxide. A time-dependent relative peroxidase-like activity follows the following order CoFe2O4-DOPA  >  MnFe2O4-DOPA  >  CuFe2O4-DOPA  >  NiFe2O4-DOPA  >  Fe3O4-DOPA. This diversity in HRP-like activity may be attributed to the different redox properties of ferrite nanoparticles when doped with M (Fe, Co Cu, Mn and Ni).

  5. Microwave Assisted Synthesis of Ferrite Nanoparticles: Effect of Reaction Temperature on Particle Size and Magnetic Properties.

    PubMed

    Kalyani, S; Sangeetha, J; Philip, John

    2015-08-01

    The preparation of ferrite magnetic nanoparticles of different particle sizes by controlling the reaction temperature using microwave assisted synthesis is reported. The iron oxide nanoparticles synthesized at two different temperatures viz., 45 and 85 °C were characterized using techniques such as X-ray diffraction (XRD), small angle X-ray scattering (SAXS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The average size of iron oxide nanoparticles synthesized at 45 and 85 °C is found to be 10 and 13.8 nm, respectively, and the nanoparticles exhibited superparamagantic behavior at room temperature. The saturation magnetization values of nanoparticles synthesized at 45 and 85 °C were found to be 67 and 72 emu/g, respectively. The increase in particle size and saturation magnetization values with increase in incubation temperature is attributed to a decrease in supersaturation at elevated temperature. The Curie temperature was found to be 561 and 566 0C for the iron oxide nanoparticles synthesized at 45 and 85 °C, respectively. The FTIR spectrum of the iron oxide nanoparticles synthesized at different temperatures exhibited the characteristic peaks that corresponded to the stretching of bonds between octahedral and tetrahedral metal ions to oxide ions. Our results showed that the ferrite nanoparticle size can be varied by controlling the reaction temperature inside a microwave reactor.

  6. Synthesis, electrical and magnetic properties of sodium borosilicate glasses containing Co-ferrites nanoparticles

    NASA Astrophysics Data System (ADS)

    Othman, H. A.; Eltabey, M. M.; Ibrahim, Samia. E.; El-Deen, L. M. Sharaf; Elkholy, M. M.

    2017-02-01

    Co-ferrites nanoparticles that have been prepared by the co-precipitation method were added to sodium borosilicate (Na2O-B2O3-SiO2) glass matrix by the solid solution method and they were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and magnetization measurements. (XRD) revealed the formation of the Co-ferrite magnetic crystalline phase embedded in an amorphous matrix in all the samples. The investigated samples by (TEM) showed the formation of the cobalt ferrite nanoparticles with a spherical shape and highly monodispersed with an average size about 13 nm. IR data revealed that the BO3 and BO4 are the main structural units of these samples network. IR spectra of the investigated samples showed the characteristic vibration bands of Co-ferrite. Composition and frequency dependent dielectric properties of the prepared samples were measured at room temperature in the frequency range 100-100 kHz. The conductivity was found to increase with increasing cobalt ferrite content. The variations of conductivity and dielectric properties with frequency and composition were discussed. Magnetic hysteresis loops were traced at room temperature using VSM and values of saturation magnetization MS and coercive field HC were determined. The obtained results revealed that a ferrimagnetic behavior were observed and as Co-ferrite concentration increases the values of MS and HC increase from 2.84 to 8.79 (emu/g) and from 88.4 to 736.3 Oe, respectively.

  7. Silica-coated manganite and Mn-based ferrite nanoparticles: a comparative study focused on cytotoxicity

    NASA Astrophysics Data System (ADS)

    Kaman, Ondřej; Dědourková, Tereza; Koktan, Jakub; Kuličková, Jarmila; Maryško, Miroslav; Veverka, Pavel; Havelek, Radim; Královec, Karel; Turnovcová, Karolína; Jendelová, Pavla; Schröfel, Adam; Svoboda, Ladislav

    2016-04-01

    Magnetic oxide nanoparticles provide a fascinating tool for biological research and medicine, serving as contrast agents, magnetic carriers, and core materials of theranostic systems. Although the applications rely mostly on iron oxides, more complex oxides such as perovskite manganites may provide a much better magnetic performance. To assess the risk of their potential use, in vitro toxicity of manganite nanoparticles was thoroughly analysed and compared with another prospective system of Mn-Zn ferrite nanoparticles. Magnetic nanoparticles of La0.63Sr0.37MnO3 manganite were prepared by two distinct methods, namely the molten salt synthesis and the traditional sol-gel route, whereas nanoparticles of Mn0.61Zn0.42Fe1.97O4 ferrite, selected as a comparative material, were synthesized by a new procedure under hydrothermal conditions. Magnetic cores were coated with silica and, moreover, several samples of manganite nanoparticles with different thicknesses of silica shell were prepared. The size-fractionated and purified products were analysed using transmission electron microscopy, dynamic light scattering, measurement of the zeta-potential dependence on pH, IR spectroscopy, and SQUID magnetometry. The silica-coated products with accurately determined concentration by atomic absorption spectroscopy were subjected to a robust evaluation of their cytotoxicity by four different methods, including detailed analysis of the concentration dependence of toxicity, analysis of apoptosis, and experiments on three different cell lines. The results, comparing two manganese-containing systems, clearly indicated superior properties of the Mn-Zn ferrite, whose silica-coated nanoparticles show very limited toxic effects and thus constitute a promising material for bioapplications.

  8. Magnesium ferrite nanoparticles: a rapid gas sensor for alcohol

    NASA Astrophysics Data System (ADS)

    Godbole, Rhushikesh; Rao, Pratibha; Bhagwat, Sunita

    2017-02-01

    Highly porous spinel MgFe2O4 nanoparticles with a high specific surface area have been successfully synthesized by a sintering free auto-combustion technique and characterized for their structural and surface morphological properties using XRD, BET, TEM and SEM techniques. Their sensing properties to alcohol vapors viz. ethanol and methanol were investigated. The site occupation of metal ions was investigated by VSM. The as-synthesized sample shows the formation of sponge-like porous material which is necessary for gas adsorption. The gas sensing characteristics were obtained by measuring the gas response as a function of operating temperature, concentration of the gas, and the response-recovery time. The response of magnesium ferrite to ethanol and methanol vapors was compared and it was revealed that magnesium ferrite is more sensitive and selective to ethanol vapor. The sensor operates at a substantially low vapor concentration of about 1 ppm of alcohol vapors, exhibits fantastic response reproducibility, long term reliability and a very fast response and recovery property. Thus the present study explored the possibility of making rapidly responding alcohol vapor sensor based on magnesium ferrite. The sensing mechanism has been discussed in co-relation with magnetic and morphological properties. The role of occupancy of Mg2+ ions in magnesium ferrite on its gas sensing properties has also been studied and is found to influence the response of magnesium ferrite ethanol sensor.

  9. Superparamagnetic magnesium ferrite nanoparticles fabricated by a simple, thermal-treatment method

    NASA Astrophysics Data System (ADS)

    Goodarz Naseri, Mahmoud; Ara, Mohammad Hossein Majles; Saion, Elias B.; Shaari, Abdul Halim

    2014-01-01

    This study investigated the synthesis of magnesium ferrite (MgFe2O4) nanoparticles with cubic symmetry that were prepared by a thermal-treatment method by using a solution that contained poly (vinyl alcohol) (PVA) as a capping agent and Mg and Fe nitrates as alternative sources of metal. Heat treatment was conducted using an electric cylinder furnace in an air atmosphere at temperatures between 673 and 973 K, and magnesium ferrite nanoparticles were produced that had different crystallite sizes ranging from5 to 8 nm. The products were well characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), X-ray analysis (EDXA), and Fourier transform infrared spectroscopy (FT-IR). All the samples calcined from 673 to 973 K exhibited super paramagnetic behavior with unpaired electrons spins, which was confirmed by using a vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR) spectroscopy.

  10. Magnetically responsive phase-change microspheres with large magnetization using ferrite nanoparticles.

    PubMed

    Du, Yufan; Wang, Yongsheng; He, Dawei; Feng, Bin; Ju, Changbin; Zhao, Huan; Fu, Ming

    2010-03-01

    Magnetically responsive phase-change microspheres were prepared and studied in this article. In the synthetic process, oleic acid was used to modify the iron oxide nanoparticles. The ferrite nanoparticles, about 10 nm in diameter, were highly dispersed due to the oleic acid on the surface of the particles, and they were encapsulated in polymethyl methacrylate (PMMA) by microemulsion polymerization with paraffin, which could be presumed from the differential scanning calorimetry (DSC) curves. According to the morphology in the scanning electron microscopy (SEM) image, the average diameter of the microspheres was about 200 nm, a large amount of nano-sized ferrite can be observed in a transmission electron microscope (TEM) image showing the structure of the microspheres. Finally, in the magnetization curve from a vibrating sample magnetometer, the saturation magnetization of microspheres was 12.2 emu/g, which was effective in the compatibility of infrared simulation and microwave absorption.

  11. Magnetic and electrical properties of In doped cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Nongjai, Razia; Khan, Shakeel; Asokan, K.; Ahmed, Hilal; Khan, Imran

    2012-10-01

    Nanoparticles of CoFe2O4 and CoIn0.15Fe1.85O4 ferrites were prepared by citrate gel route and characterized to understand their structural, electrical, and magnetic properties. X-ray diffraction and Raman spectroscopy were used to confirm the formation of single phase cubic spinel structure. The average grain sizes from the Scherrer formula were below 50 nm. Microstructural features were obtained by scanning electron microscope and compositional analysis by energy dispersive spectroscopy. The hysteresis curve shows enhancement in coercivity while reduction in saturation magnetization with the substitution of In3+ ions. Enhancement of coercivity is attributed to the transition from multidomain to single domain nature. Electrical properties, such as dc resistivity as a function of temperature and ac conductivity as a function of frequency and temperature were studied for both the samples. The activation energy derived from the Arrhenius equation was found to increase in the doped sample. The dielectric constant (ɛ') and dielectric loss (tan δ) are also studied as a function of frequency and temperature. The variation of dielectric properties ɛ', tan δ, and ac conductivity (σac) with frequency reveals that the dispersion is due to Maxwell-Wagner type of interfacial polarization in general and the hopping of charge between Fe2+ and Fe3+ as well as between Co2+ and Co3+ ions at B-sites. Magnetization and electrical property study showed its dominant dependence on the grain size.

  12. Dye removal using modified copper ferrite nanoparticle and RSM analysis.

    PubMed

    Mahmoodi, Niyaz Mohammad; Soltani-Gordefaramarzi, Sajjad; Sadeghi-Kiakhani, Moosa

    2013-12-01

    In this paper, copper ferrite nanoparticle (CFN) was synthesized, modified by cetyl trimethylammonium bromide, and characterized. Dye removal ability of the surface modified copper ferrite nanoparticle (SMCFN) from single system was investigated. The physical characteristics of SMCFN were studied using Fourier transform infrared, scanning electron microscopy, and X-ray diffraction. Acid Blue 92, Direct Green 6, Direct Red 23, and Direct Red 80 were used as model compounds. The effect of operational parameters (surfactant concentration, adsorbent dosage, dye concentration, and pH) on dye removal was evaluated. Response surface methodology (RSM) was used for the analysis of the dye removal data. The experimental checking in these optimal conditions confirms good agreements with RSM results. The results showed that the SMCFN being a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions.

  13. Structure and magnetic properties of ZnO coated MnZn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Mallesh, Shanigaram; Sunny, Annrose; Vasundhara, Mutta; Srinivas, Veeturi

    2016-11-01

    A comparative study of structural and magnetic properties of MnZn spinel ferrite (SF) and ZnO coated MnZn ferrite (ZF) nanoparticles (NPs) has been carried out. The as-prepared NPs show a single phase cubic spinel structure, with lattice parameter ~8.432 Å. However, α-Fe2O3 impurity phase emerge from SF particles when subjected to annealing at 600 °C in air. The weight fraction of α-Fe2O3 phase increases with increasing Mn concentration (9% for x=0.2 and 53% for x=0.6). On the other hand in ZF (x=0.2 and 0.4) NPs no trace of impurity phase is observed when annealed at 600 °C. The magnetic measurements as a function of field and temperature revealed superparamagnetic like behavior with cluster moment ~104 μB in as-prepared particles. The cluster size obtained from the magnetic data corroborates well with that estimated from structural analysis. Present results on ZnO coated MnZn ferrite particles suggest that an interfacial (ZnO@SF) reaction takes place during annealing, which results in formation of Zn-rich ferrite phase in the interface region. This leads to deterioration of magnetic properties even in the absence of α-Fe2O3 impurity phase.

  14. Micro Raman, Mossbauer and magnetic studies of manganese substituted zinc ferrite nanoparticles: Role of Mn

    NASA Astrophysics Data System (ADS)

    Thota, Suneetha; Kashyap, Subhash C.; Sharma, Shiv K.; Reddy, V. R.

    2016-04-01

    A series of Mn-Zn Ferrite nanoparticles (<15 nm) with formula MnxZn1-xFe2O4 (where x=0.00, 0.35, 0.50, 0.65) were successfully prepared by citrate-gel method at low temperature (400 °C). X-ray diffraction analysis confirmed the formation of single cubic spinel phase in these nanoparticles. The FESEM and TEM micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The fractions of Mn2+, Zn2+ and Fe3+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of different ferrite samples are estimated by room temperature micro-Raman spectroscopy. Low temperature Mossbauer measurement on Mn0.5Zn0.5Fe2O4 has reconfirmed the mixed spinel phase of these nanoparticles. Room temperature magnetization studies (PPMS) of Mn substituted samples showed superparamagnetic behavior. Manganese substitution for Zn in the ferrite caused the magnetization to increase from 04 to18 emu/g and Lande's g factor (estimated from ferromagnetic resonance measurement) from 2.02 to 2.12 when x was increased up to 0.50. The FMR has shown that higher Mn cationic substitution leads to increase in dipolar interaction and decrease in super exchange interaction. Thermomagnetic (M-T) and magnetization (M-H) measurements have shown that the increase in Mn concentration (up to x=0.50) enhances the spin ordering temperature up to 150 K (blocking temperature). Magnetocrystalline anisotropy in the nanoparticles was established by Mossbauer, ferromagnetic resonance and thermomagnetic measurements. The optimized substitution of manganese for zinc improves the magnetic properties and makes these nanoparticles a potential candidate for their applications in microwave region and biomedical field.

  15. Surface effects in the magnetic properties of crystalline 3 nm ferrite nanoparticles chemically synthesized

    NASA Astrophysics Data System (ADS)

    Lima, E.; De Biasi, E.; Mansilla, M. Vasquez; Saleta, M. E.; Effenberg, F.; Rossi, L. M.; Cohen, R.; Rechenberg, H. R.; Zysler, R. D.

    2010-11-01

    We have systematically studied the magnetic properties of ferrite nanoparticles with 3, 7, and 11 nm of diameter with very narrow grain size distributions. Samples were prepared by the thermal decomposition of Fe(acac)3 in the presence of surfactants giving nanoparticles covered by oleic acid. High resolution transmission electron microscopy (HRTEM) images and XRD diffraction patterns confirms that all samples are composed by crystalline nanoparticles with the spinel structure expected for the iron ferrite. ac and dc magnetization measurements, as well in-field Mössbauer spectroscopy, indicate that the magnetic properties of nanoparticles with 11 and 7 nm are close to those expected for a monodomain, presenting large MS (close to the magnetite bulk). Despite the crystalline structure observed in HRTEM images, the nanoparticles with 3 nm are composed by a magnetically ordered region (core) and a surface region that presents a different magnetic order and it contains about 66% of Fe atoms. The high saturation and irreversibility fields in the M(H ) loops of the particles with 3 nm together with the misalignment at 120 kOe in the in-field Mössbauer spectrum of surface component indicate a high surface anisotropy for the surface atoms, which is not observed for the core. For T <10 K, we observe an increase in the susceptibility and of the magnetization for former sample, indicating that surface moments tend to align with applied field increasing the magnetic core size.

  16. Cr3+ substituted spinel ferrite nanoparticles with high coercivity

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Zuo, Xudong; Zhang, Dongmei; Wu, Chengwei; Silva, S. Ravi P.

    2016-06-01

    The low coercivity of spinel ferrites is a major barrier that significantly limits their use in high density magnetic recording applications. By controlling the substituting content of Cr3+, in this article we describe how magnetic CoCr x Fe2-x O4 (0 < x < 1.2) nanoparticles with coercivity of up to 6.4 kOe were successfully obtained by the hydrothermal process. The high coercivity is attributed to the synergetic effects of magnetocrystalline anisotropy and the nanoscale size effect. X-ray diffraction analysis confirmed the spinel structure of the nanoparticles with transmission electron microscopy (TEM) suggesting regular tetragonal morphology. The TEM indicated an edge length ranging from 15 nm to 150 nm, which increases monotonically with increasing Cr content. Raman analyses supported the proposed model on the formation mechanism of the nanoparticles, i.e. heterogeneous and homogeneous nucleation.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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

  18. Oxidative stress mediated apoptosis induced by nickel ferrite nanoparticles in cultured A549 cells.

    PubMed

    Ahamed, Maqusood; Akhtar, Mohd Javed; Siddiqui, Maqsood A; Ahmad, Javed; Musarrat, Javed; Al-Khedhairy, Abdulaziz A; AlSalhi, Mohamad S; Alrokayan, Salman A

    2011-05-10

    Due to the interesting magnetic and electrical properties with good chemical and thermal stabilities, nickel ferrite nanoparticles are being utilized in many applications including magnetic resonance imaging, drug delivery and hyperthermia. Recent studies have shown that nickel ferrite nanoparticles produce cytotoxicity in mammalian cells. However, there is very limited information concerning the toxicity of nickel ferrite nanoparticles at the cellular and molecular level. The aim of this study was to investigate the cytotoxicity, oxidative stress and apoptosis induction by well-characterized nickel ferrite nanoparticles (size 26 nm) in human lung epithelial (A549) cells. Nickel ferrite nanoparticles induced dose-dependent cytotoxicity in A549 cells demonstrated by MTT, NRU and LDH assays. Nickel ferrite nanoparticles were also found to induce oxidative stress evidenced by generation of reactive oxygen species (ROS) and depletion of antioxidant glutathione (GSH). Further, co-treatment with the antioxidant L-ascorbic acid mitigated the ROS generation and GSH depletion due to nickel ferrite nanoparticles suggesting the potential mechanism of oxidative stress. Quantitative real-time PCR analysis demonstrated that following the exposure of A549 cells to nickel ferrite nanoparticles, the level of mRNA expressions of cell cycle checkpoint protein p53 and apoptotic proteins (bax, caspase-3 and caspase-9) were significantly up-regulated, whereas the expression of anti-apoptotic proteins (survivin and bcl-2) were down-regulated. Moreover, activities of caspase-3 and caspase-9 enzymes were also significantly higher in nickel ferrite nanoparticles exposed cells. To the best of our knowledge this is the first report showing that nickel ferrite nanoparticles induced apoptosis in A549 cells through ROS generation and oxidative stress via p53, survivin, bax/bcl-2 and caspase pathways.

  19. Spindly cobalt ferrite nanocrystals: preparation, characterization and magnetic properties.

    PubMed

    Cao, Xuebo; Gu, Li

    2005-02-01

    In this paper we describe the preparation of homogeneously needle-shaped cobalt ferrite (CoFe(2)O(4)) nanocrystals on a large scale through the smooth decomposition of urea and the resulting co-precipitation of Co(2+) and Fe(3+) in oleic acid micelles. Furthermore, we found that other ferrite nanocrystals with a needle-like shape, such as zinc ferrite (ZnFe(2)O(4)) and nickel ferrite (NiFe(2)O(4)), can be prepared by the same process. Needle-shaped CoFe(2)O(4) nanocrystals dispersed in an aqueous solution containing oleic acid exhibit excellent stability and the formed colloid does not produce any precipitations after two months, which is of prime importance if these materials are applied in magnetic fluids. X-ray diffraction (XRD) measurements were used to characterize the phase and component of the co-precipitation products, and demonstrate that they are spinel ferrite with a cubic symmetry. Transmission electron microscopy (TEM) observation showed that all the nanocrystals present a needle-like shape with a 22 nm short axis and an aspect ratio of around 6. Varying the concentration of oleic acid did not bring about any obvious influence on the size distribution and shapes of CoFe(2)O(4). The magnetic properties of the needle-shaped CoFe(2)O(4) nanocrystals were evaluated by using a vibrating sample magnetometer (VSM), electron paramagnetic resonance (EPR), and a Mössbauer spectrometer, and the results all demonstrated that CoFe(2)O(4) nanocrystals were superparamagnetic at room temperature.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  2. Effect of surface coating on magnetic properties of cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Chithra, M.; Anumol, C. N.; Sahoo, Subasa C.

    2016-05-01

    Cobalt ferrite nanoparticles were synthesized by coprecipitation method with and without surface coating. Oleic acid and citric acid were used as the surfactant during synthesis of nanoparticles. The sample prepared without coating and with (1M) oleic acid as surfactant showed crystalline nature whereas the sample prepared with (1M) citric acid was X-ray amorphous. The grain size was decreased with the addition of surfactant during synthesis. It was also observed that with the decrease in concentration of citric acid, grain size was increased. The sample prepared with (1M) citric acid was superparamagnetic and the other samples were ferrimagnetic in nature with magnetization value less than the bulk value of 80emu/g at 300K. Magnetization, remanence and coercivity values were decreased in the samples prepared with coating in comparison to the sample prepared without coating. As the temperature decreased from 300K to 60K all the magnetic properties mentioned above were enhanced. The observed magnetic properties of these nanoparticles can be attributed to the grain size, effect of surface coating and magnetic interactions in these nanoparticles.

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

    PubMed Central

    2012-01-01

    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

  4. Hydrothermal synthesis of fine stabilized superparamagnetic nanoparticles of Zn2+ substituted manganese ferrite

    NASA Astrophysics Data System (ADS)

    Zahraei, Maryam; Monshi, Ahmad; Morales, Maria del Puerto; Shahbazi-Gahrouei, Daryoush; Amirnasr, Mehdi; Behdadfar, Behshid

    2015-11-01

    Superparamagnetic Zn2+ substituted manganese ferrite Mn1-xZnxFe2O4 (x=0.3, 0.35, 0.4 and 0.45) nanoparticles (NPs) were synthesized via a direct, efficient and environmental friendly hydrothermal method. The synthesized NPs were characterized by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM), thermo-gravimetry (TG) and vibrating sample magnetometry (VSM). The effects of various parameters such as the pH of reaction mixture, time and temperature of hydrothermal treatment and Zn substitution on the spinel phase formation, the magnetization, and the size of resulting NPs are discussed. The Zn2+ substituted manganese ferrite NPs obtained from hydrothermal process crystallized mainly in the spinel phase. Nevertheless, without citrate ions, the hematite phase appeared in the product. The monophase Zn2+ substituted manganese ferrite NPs hydrothermally prepared in the presence of citric acid had mean particle size of 7 nm and a narrow size distribution. Furthermore, the synthesized NPs can be used to prepare ferrofluids for biomedical applications due to their small size, good stability in aqueous medium (pH 7) and also high magnetization value.

  5. Microwave synthesis and characterization of Co-ferrite nanoparticles.

    PubMed

    Bensebaa, F; Zavaliche, F; L'Ecuyer, P; Cochrane, R W; Veres, T

    2004-09-01

    Stable CoFe(2)O(4) nanoparticles have been obtained by co-precipitation using a microwave heating system. Transmission electron microscopy images analysis shows an agglomeration of particles with an average size of about 5 nm, and X-ray diffraction reveals the presence of a pure ferrite nanocrystalline phase. X-ray photoelectron spectroscopy and thermal gravimetric analysis show the presence of organic matter in the range of about 16 wt%. The magnetic response in DC fields is typical for an assembly of single-domain particles. The measured saturation magnetization is slightly larger than the bulk value, probably due to the presence of small amounts of Co and Fe. AC magnetization data indicate the presence of magnetic interactions between the nanoparticles.

  6. Cobalt ferrite nanoparticles in a mesoporous silicon dioxide matrix

    NASA Astrophysics Data System (ADS)

    Komogortsev, S. V.; Patrusheva, T. N.; Balaev, D. A.; Denisova, E. A.; Ponomarenko, I. V.

    2009-10-01

    We have studied magnetic nanoparticles of cobalt ferrite obtained by the extraction-pyrolysis method in a mesoporous silicon dioxide (MSM-41) molecular sieve matrix. The X-ray diffraction data show evidence for the formation of CoFe2O4 particles with a coherent scattering domain size of ˜40 nm. Measurements of the magnetization curves showed that powders consisting of these nanoparticles are magnetically hard materials with a coercive field of H c(4.2 K) = 9.0 kOe and H c(300 K) = 1.8 kOe and a reduced remanent magnetization of M r/ M s(4.2 K) = 0.83 and M r/ M s(300 K) = 0.49. The shape of the low-temperature (4.2 K) magnetization curves is adequately described in terms of the Stoner-Wohlfarth model for randomly oriented single-domain particles with a cubic magnetic anisotropy.

  7. Study of Zn-Cu Ferrite Nanoparticles for LPG Sensing

    PubMed Central

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

    2013-01-01

    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

  8. Study of Zn-Cu ferrite nanoparticles for LPG sensing.

    PubMed

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

    2013-01-01

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

  9. Polyethylene glycol coated CoFe{sub 2}O{sub 4} nanoparticles: A potential spinel ferrite for biomedical applications

    SciTech Connect

    Humbe, Ashok V.; Birajdar, Shankar D.; Jadhav, K. M.; Bhandari, J. M.; Waghule, N. N.; Bhagwat, V. R.

    2015-06-24

    The structural and magnetic properties of the polyethylene glycol (PEG) coated cobalt spinel ferrite (CoFe{sub 2}O{sub 4}) nanoparticles have been reported in the present study. CoFe{sub 2}O{sub 4} nanoparticles were prepared by sol-gel auto-combustion method using citric acid + ethylene glycol as a fuel. The prepared powder of cobalt ferrite nanoparticles was annealed at 600°C for 6h and used for further study. The structural characterization of CoFe{sub 2}O{sub 4} nanoparticles were carried out by X-ray diffraction technique. The X-ray analysis confirmed the formation of single phase cubic spinel structure. The crystallite size, Lattice constant and X-ray density of the PEG coated CoFe{sub 2}O{sub 4} nanoparticles were calculated by using XRD data. The presence of PEG on CoFe{sub 2}O{sub 4} nanoparticles and reduced agglomeration in the CoFe{sub 2}O{sub 4} nanoparticles were revealed by SEM studies. The magnetic properties were studied by pulse field hysteresis loop tracer technique at a room temperature. The magnetic parameters such as saturation magnetization, remanence magnetization, coercivity etc have been obtained. These magnetic parameters were get decreased by PEG coating.

  10. Size and compositionally controlled manganese ferrite nanoparticles with enhanced magnetization

    NASA Astrophysics Data System (ADS)

    Vamvakidis, K.; Sakellari, D.; Angelakeris, M.; Dendrinou-Samara, C.

    2013-06-01

    A facile solvothermal approach was used to synthesize stable, superparamagnetic manganese ferrite nanoparticles with relatively small sizes (<10 nm) and enhanced magnetic features. Tetraethylene glycol has been used in all the syntheses as a biocompatible and stabilizing agent. By varying the oxidation state of manganese precursor, Mn(acac)2 to Mn(acac)3, different sizes, 8 and 5 nm, of MnFe2O4 nanoparticles were obtained respectively, while by tailoring the synthetic conditions iron-rich Mn0.77Fe2.23O4 nanoparticles have been isolated with identical sizes and enhanced saturation magnetization. The magnetization values increased from 58.2 to 68.3 Am2/kg and from 53.3 to 60.2 Am2/kg for the nanoparticles of 8 and 5 nm, respectively. Blocking temperature ( T B), ranging from 80 to 180 K, and anisotropy constant ( K eff), ranging from 1.5 × 105 to 4.9 × 105 J/m3, were found higher for the iron-rich samples and associated with size and composition effects.

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

    PubMed

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

    2013-01-01

    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 μg/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.

  12. One-pot production of copper ferrite nanoparticles using a chemical method

    NASA Astrophysics Data System (ADS)

    Nishida, Naoki; Amagasa, Shota; Kobayashi, Yoshio; Yamada, Yasuhiro

    2016-12-01

    Copper ferrite nanoparticles were synthesized via the oxidation of precipitates obtained from the reaction of FeCl2, CuSO4 and N2H4 in the presence of gelatin. These copper ferrite particles were subsequently examined using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and Mössbauer spectroscopy. The average size of the copper ferrite nanoparticles was less than 5 nm, and they exhibited superparamagnetic behavior as a result of their small size. The low temperature Mössbauer spectrum exhibited three sets of sextets, two corresponding to the tetrahedral and octahedral sites of the copper spinel structure and one with small hyperfine magnetic field corresponding to the surface or defects of the nanoparticles. When the ratio of copper salt was increased, the tetrahedral site became preferable for copper, and metallic copper and copper ferrite were both present in a single nanoparticle.

  13. Effect of gamma irradiation on the structural and magnetic properties of Co–Zn spinel ferrite nanoparticles

    SciTech Connect

    Raut, Anil V.; Kurmude, D.V.; Shengule, D.R.; Jadhav, K.M.

    2015-03-15

    Highlights: • Co–Zn ferrite nanoparticles were examined before and after γ-irradiation. • Single phase cubic spinel structure of Co–Zn was confirmed by XRD data. • The grain size was reported in the range of 52–62 nm after γ-irradiation. • Ms, Hc, n{sub B} were reported to be increased after gamma irradiation. - Abstract: In this work, the structural and magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 1.0) ferrite nanoparticles were studied before and after gamma irradiation. The as-synthesized samples of Co–Zn ferrite nanoparticles prepared by sol–gel auto-combustion technique were analysed by XRD which suggested the single phase; cubic spinel structure of the material. Crystal defects produced in the spinel lattice were studied before and after Co{sup 60} γ-irradiation in a gamma cell with a dose rate of 0.1 Mrad/h in order to report the changes in structural and magnetic properties of the Co–Zn ferrite nanoparticles. The average crystallite size (t), lattice parameter (α) and other structural parameters of gamma-irradiated and un-irradiated Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} spinel ferrite system was calculated from XRD data. The morphological characterizations were performed using scanning electron microscopy (SEM). The magnetic properties were measured using pulse field hysteresis loop tracer by applying magnetic field of 1000 Oe, and the analysis of data obtained revealed that the magnetic property such as saturation magnetization (Ms), coecivity (Hc), magneton number (n{sub B}) etc. magnetic parameters were increased after irradiation.

  14. Size-dependent antimicrobial properties of the cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Žalnėravičius, Rokas; Paškevičius, Algimantas; Kurtinaitiene, Marija; Jagminas, Arūnas

    2016-10-01

    The growing resistance of bacteria to conventional antibiotics elicited considerable interest to non-typical drugs. In this study, antimicrobial investigations were performed on low-size dispersion cobalt ferrite nanoparticles (Nps) fabricated by co-precipitation approach in several average sizes, in particular, 15.0, 5.0, and 1.65 nm. A variety of experimental tests demonstrated that the size of these Nps is determinant for antimicrobial efficiency against S. cerevisiae and several Candida species, in particular, C. parapsilosis, C. krusei, and C. albicans. The small and ultra-small fractions of CoFe2O4 Nps possess especially strong antimicrobial activity against all tested microorganisms. The possible reasons are discussed. Nps were characterized by means of transmission and high-resolution transmission electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and atomic force microscopy, chemical analysis and magnetic measurements.

  15. Direct dyes removal using modified magnetic ferrite nanoparticle

    PubMed Central

    2014-01-01

    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

  16. Microwave-hydrothermal synthesis of perovskite bismuth ferrite nanoparticles

    SciTech Connect

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

    2011-12-15

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

  17. Influence of Ce-Substitution on Structural, Magnetic and Electrical Properties of Cobalt Ferrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Hashhash, A.; Kaiser, M.

    2016-01-01

    Nano-crystalline samples of cerium substituted cobalt ferrites with chemical formula CoCe x Fe2- x O4 (0.0 ≤ x ≤ 0.1) were prepared using the citrate auto-combustion method. The prepared ferrites were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy spectra (FTIR), transmission electron microscopy (TEM), and a vibrating sample magnetometer (VSM). The XRD patterns and FTIR spectra confirm that the prepared samples reveal the formation of a single-phase spinel structure. TEM micrographs showed that the particles are made up of spherical and elongated nano-metric shapes. A limitation of the size of nanoparticles is observed as the Ce3+ concentration increases. VSM measurements showed that the coercivity H c and magnetization values M s are strongly dependent on Ce3+ content and particle size. The values of H c lie in the range of (411-1600 G), which suggest that these samples are convenient for different applications. The alternating current electrical conductivity ( σ), dielectric permittivities ( ɛ', ɛ″), and dielectric loss tangent (tan δ) were studied at different ranges of frequency and temperature. The relation of conductivity with temperature revealed a semiconductor to semi-metallic behavior as cerium concentration increases. The variation in (tan δ) with frequency at different temperature shows abnormal behavior with more than one relaxation peak. The conduction mechanism used in the present study has been discussed in the light of cation-anion-cation interactions over the octahedral B-site.

  18. Electromagnetic properties of NiZn ferrite nanoparticles and their polymer composites

    SciTech Connect

    Parsons, P.; Duncan, K.; Giri, A. K.; Xiao, J. Q.; Karna, S. P.

    2014-05-07

    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.

  19. Radiation induced structural and magnetic transformations in nanoparticle MnxZn(1-x)Fe2O4 ferrites

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    Nanoparticle magnetic materials are suitable for multiple modern high end medical applications like targeted drug delivery, gene therapy, hyperthermia and MR thermometry imaging. Majority of these applications are confined to use of Mn-Zn ferrite nanoparticles. These nanoparticles are normally left in the body after their requisite application. Preparing these nanoparticles is usually a much involved job. However with the development of the simple technique MnxZn1-xFe2O4 nanoparticles could be prepared with much ease. The nanoparticles of MnxZn1-xFe2O4 with (x=1.0, 0.7, 0.5, 0.3, 0.0) were prepared and irradiated with gamma radiation of various intensities ranging between 500 R to 10,000 R, after appropriate structural and magnetic characterization. Irradiated samples were investigated for structural and magnetic properties, as well as for structural stability and cation distribution. The irradiated nanoparticles exhibited structural stability with varied cation distribution and magnetic properties, dependent on gamma radiation dose. Surprisingly samples also exhibited quenching of lattice parameter and particle size. The changes introduced in the cation distribution, lattice constant, particle size and magnetic properties were found to be irreversible with time lapse and were of permanent nature exhibiting good stability even after several months. Thus the useful properties of nanoparticles could be enhanced on modifying the cation distribution inside the nanoparticles by application of gamma radiation.

  20. Effect of sintering temperature on magnetization and Mössbauer parameters of cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Chandra, Grish; Srivastava, R. C.; Reddy, V. R.; Agrawal, H. M.

    2017-04-01

    Nanoparticles of cobalt ferrite of different particle size were prepared using sol-gel method. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy techniques were employed for characterization of nanoparticles for structural and magnetic properties. The particle size and saturation magnetization increase with the increase of sintering temperature. The saturation magnetization increases from 53 to 85 emu/g as the sintering temperature increases from 300 to 900 °C. The remanence increases while the coercivity decreases slightly with the increase of sintering temperature. Mössbauer spectra show the ferrimagnetic nature of all the samples and the cation distribution strictly depends on the sintering temperature. The stoichiometry of the cobalt ferrite formed was estimated to be (Co2+xFe3+1-x)[Co2+1-xFe3+1+x]O4, based on our Mössbauer analysis. The inverse spinel structure gradually transforms towards the normal spinel structure as the sintering temperature increases.

  1. Structural and magnetic studies on Mn-doped Ni-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Ramesh, S.; Dhanalakshmi, B.; Chandra Sekhar, B.; Subba Rao, P. S. V.; Parvatheeswara Rao, B.

    2016-11-01

    Ni-Zn ferrite nanoparticles with manganese substitutions, Ni0.4Zn0.6- x Mn x Fe2O4, where x varies from 0.00 to 0.25 in steps of 0.05, were prepared using sol-gel autocombustion method. The resultant nanoparticles were analyzed using X-ray diffractometry, transmission electron microscopy, thermogravimetry and vibrating sample magnetometer measurements. X-ray diffraction patterns confirm single-phase cubic spinel structures with crystallite sizes in the range from 25.43 to 37.23 nm. Particle sizes obtained from transmission electron micrographs were also in good agreement with the crystallite sizes obtained from the X-ray data. Saturation magnetization and coercivity data for all the samples obtained from the corresponding M-H loops suggest a sinusoidal variations with Mn concentration ( x) implying that the substitution of Mn in the given nano-sized Ni-Zn ferrite system seems to have brought in a profound influence not only on the site preferences of other cations in the system but also in bringing about modifications in its own site preferences. The results are analyzed in terms of the compositional and structural modifications, and it was found that the observed magnetic variation was governed by the crystallite size and the corresponding change in cationic preferences in these materials.

  2. Synthesis and characterization of Co-Zn ferrite nanoparticles for application to magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Choi, Hyunkyung; Lee, Sangjoon; Kouh, Taejoon; Kim, Sam Jin; Kim, Chul Sung; Hahn, Eunjoo

    2017-01-01

    Co-Zn ferrite nanoparticles have been investigated, aiming at a further improvement of the magnetic hyperthermia properties for bio-medical applications. We precisely tune the magnetic and the thermal properties of Co x Zn1- x Fe2O4 nanoparticles, prepared by using a high-temperature thermal-decomposition method, by chemically controlling the cation. The structure and the magnetic properties as well as the AC-heating characteristics of the synthesized Co x Zn1- x Fe2O4 were measured by using X-ray diffraction (XRD), vibrating sample magnetometer, magneTherm device and Mössbauer spectroscopy. The analysis of the XRD patterns confirmed the spinel phase, the crystalline size, and the lattice parameter. The magnetic behavior of Co-Zn ferrite was studied with M-H hysteresis curve measurements at room temperature. Also, the thermal properties were measured under an external applied field of 250 Oe at 112 kHz. In addition, we plasma-treated the samples with magnetic and thermal excellent characteristics for 30 min at room temperature. The cation distribution was investigated with Mössbauer spectroscopy and further analyzed with one sextet for the tetrahedral A site and four six-lines for the octahedral B1, B2, B3, and B4 sites.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Ghasemi, Ali

    2013-03-01

    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.

  5. Synthesis and cytotoxicity study of magnesium ferrite-gold core-shell nanoparticles.

    PubMed

    Nonkumwong, Jeeranan; Pakawanit, Phakkhananan; Wipatanawin, Angkana; Jantaratana, Pongsakorn; Ananta, Supon; Srisombat, Laongnuan

    2016-04-01

    In this work, the core-magnesium ferrite (MgFe2O4) nanoparticles were prepared by hydrothermal technique. Completed gold (Au) shell coating on the surfaces of MgFe2O4 nanoparticles was obtained by varying core/shell ratios via a reduction method. Phase identification, morphological evolution, optical properties, magnetic properties and cytotoxicity to mammalian cells of these MgFe2O4 core coated with Au nanoparticles were examined by using a combination of X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, UV-visible spectroscopy (UV-vis), vibrating sample magnetometry and resazurin microplate assay techniques. In general, TEM images revealed different sizes of the core-shell nanoparticles generated from various core/shell ratios and confirmed the completed Au shell coating on MgFe2O4 core nanoparticles via suitable core/shell ratio with particle size less than 100 nm. The core-shell nanoparticle size and the quality of coating influence the optical properties of the products. The UV-vis spectra of complete coated MgFe2O4-Au core-shell nanoparticles exhibit the absorption bands in the near-Infrared (NIR) region indicating high potential for therapeutic applications. Based on the magnetic property measurement, it was found that the obtained MgFe2O4-Au core-shell nanoparticles still exhibit superparamagnetism with lower saturation magnetization value, compared with MgFe2O4 core. Both of MgFe2O4 and MgFe2O4-Au core-shell also showed in vitro non-cytotoxicity to mouse areola fibroblast (L-929) cell line.

  6. Preparation of transparent conductors ferroelectric memory materials and ferrites

    DOEpatents

    Bhattacharya, Raghu Nath; Ginley, David S.

    1998-01-01

    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.

  7. Preparation of transparent conductors ferroelectric memory materials and ferrites

    DOEpatents

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

    1998-07-28

    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.

  8. Synthesis and Characterization of Cobalt Substituted Zinc Ferrite Nanoparticles by Microwave Combustion Method.

    PubMed

    Sundararajan, M; Kennedy, L John; Vijaya, J Judith

    2015-09-01

    Pure and cobalt doped zinc ferrites were prepared by microwave combustion method using L-arginine as a fuel. The prepared samples were characterized by various instrumental techniques such as X-ray powder diffractometry, high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis, Fourier transformed infrared (FT-IR) spectroscopy, photoluminescence spectroscopy and UV-Visible diffuse reflectance spectroscopy. Vibrating sample magnetometry at room temperature was recorded to study the magnetic behavior of the samples. X-ray analysis confirmed the formation of zinc ferrites normal spinel-type structure with an average crystallite sizes in the range, 25.69 nm to 35.68 nm. The lattice parameters decreased as cobalt fraction was increased. The HR-SEM images showed nanoparticles are agglomerated. The estimated band gap energy value was found to decrease with an increase in cobalt content (1.87 to 1.62 eV). Broad visible emissions are observed in the photoluminescence spectra. A gradual increase in the coercivity and saturation magnetization (M(s)) were noted at relatively higher cobalt doping fractions.

  9. Structural, dielectric and magnetic properties of Gd substituted manganese ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Murugesan, C.; Sathyamoorthy, B.; Chandrasekaran, G.

    2015-08-01

    Gd3+ ion-substituted manganese ferrite nanoparticles with the chemical formula MnGdxFe2-xO4 (x = 0.0, 0.05, and 0.1) were synthesized by sol-gel auto combustion method. Thermal stability of the as-prepared sample was analyzed using thermo gravimetric and differential thermal analysis (TG-DTA) and the result reveals that the prepared sample is thermally stable above 300 °C. Structural and morphology studies were performed using powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Indexed PXRD patterns confirm the formation of pure cubic spinel structure. The average crystallite sizes calculated using Sherrer’s formula decreased from 47 nm to 32 nm and lattice constant was enhanced from 8.407 Å to 8.432 Å. The FTIR spectrum of manganese ferrite shows a high frequency vibrational band at 564 cm-1 assigned to tetrahedral site and a low frequency vibrational band at 450 cm-1 assigned to octahedral site which are shifted to 556 cm-1 and 439 cm-1 for Gd3+ substitution and confirm the incorporation of Gd3+ into manganese ferrite. SEM analysis shows the presence of agglomerated spherical shaped particles at the surface. Room temperature dielectric and magnetic properties were studied using broadband dielectric spectroscopy (BDS) and vibrating sample magnetometry (VSM). Frequency dependent dielectric constant, ac conductivity and tan delta were found to increase with Gd3+ ion substitution. The measured values of saturation magnetization decrease from 46.6 emu g-1 to 41 emu g-1 with increase in Gd3+ concentration and coercivity decreases from 179.5 Oe to 143 Oe.

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

    PubMed Central

    2011-01-01

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

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

    PubMed

    Bayrakdar, H; Yalçın, O; Cengiz, U; Özüm, S; Anigi, E; Topel, O

    2014-11-11

    α-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 α-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 α-doping on the structural and morphological properties have been investigated in detail. The effect of EDTA-assisted synthesis for α-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.

  12. Magnetization anomalies of nanosize zinc ferrite particles prepared using electrodeposition

    NASA Astrophysics Data System (ADS)

    Roy, M. K.; Verma, H. C.

    2006-11-01

    Nanosize zinc ferrite particles have been prepared for the first time using electrodeposition. Zinc and iron are deposited on the cathode from a common bath containing the salts of zinc and iron. The deposited materials were forced to undergo electrochemical oxidation in a strong alkaline solution (1 M KOH) to convert them into oxides. Crystallization in ZnFe 2O 4 structure was obtained by heating the deposited material at appropriate temperature. X-ray diffraction pattern confirmed that the procedure leads to the formation of pure phase of ZnFe 2O 4. The magnetization value for the smallest size ZnFe 2O 4 is much smaller than that for the ZnFe 2O 4 made by most of the other methods although it shows a nice hysteresis shape. The magnetization shows very little variation with size in the range studied.

  13. Synthesis of ferrite and nickel ferrite nanoparticles using radio-frequency thermal plasma torch

    NASA Astrophysics Data System (ADS)

    Son, S.; Taheri, M.; Carpenter, E.; Harris, V. G.; McHenry, M. E.

    2002-05-01

    Nanocrystalline (NC) ferrite powders have been synthesized using a 50 kW-3 MHz rf thermal plasma torch for high-frequency soft magnet applications. A mixed powder of Ni and Fe (Ni:Fe=1:2), a NiFe permalloy powder with additional Fe powder (Ni:Fe=1:2), and a NiFe permalloy powder (Ni:Fe=1:1) were used as precursors for synthesis. Airflow into the reactor chamber was the source of oxygen for oxide formation. XRD patterns clearly show that the precursor powders were transformed into NC ferrite particles with an average particle size of 20-30 nm. SEM and TEM studies indicated that NC ferrite particles had well-defined polygonal growth forms with some exhibiting (111) faceting and many with truncated octahedral and truncated cubic shapes. The Ni content in the ferrite particles was observed to increase in going from mixed Ni and Fe to mixed permalloy and iron and finally to only permalloy starting precursor. The plasma-torch synthesized ferrite materials using exclusively the NiFe permalloy precursor had 40%-48% Ni content in the Ni-ferrite particle, differing from the NiFe2O4 ideal stoichiometry. EXAFS was used to probe the cation coordination in low Ni magnetite species. The coercivity and Neel temperature of the high Ni content ferrite sample were 58 Oe and ˜590 °C, respectively.

  14. Liquid-phase syntheses of cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Sinkó, Katalin; Manek, Enikő; Meiszterics, Anikó; Havancsák, Károly; Vainio, Ulla; Peterlik, Herwig

    2012-06-01

    The aim of the present study was to synthesize cobalt-ferrite (CoFe2O4) nanoparticles using various liquid phase methods; sol-gel route, co-precipitation process, and microemulsion technique. The effects of experimental parameters on the particle size, size distribution, morphology, and chemical composition have been studied. The anions of precursors (chloride and nitrate), the solvents (water, n-propanol, ethanol, and benzyl alcohol), the precipitating agent (ammonia, sodium carbonate, and oxalic acid), the surfactants (polydimethylsiloxane, ethyl acetate, citric acid, cethyltrimethylammonium bromide, and sodium dodecil sulfate), their concentrations, and heat treatments were varied in the experiments. The smallest particles (around 40 nm) with narrow polydispersity and spherical shape could be achieved by a simple, fast sol-gel technique in the medium of propanol and ethyl acetate. The size characterization methods have also been investigated. Small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and scanning electron microscopy (SEM) provide the comparison of methods. The SAXS data correspond with the sizes detected by SEM and differ from DLS data. The crystalline phases, morphology, and chemical composition of the particles with different shapes have been analyzed by X-ray diffraction, SEM, and energy dispersive X-ray spectrometer.

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

    PubMed

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

    2010-09-01

    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).

  16. Effect of PVP as a capping agent in single reaction synthesis of nanocomposite soft/hard ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Ahmad, H. A.; Saiden, N. M.; Saion, E.; Azis, R. S.; Mamat, M. S.; Hashim, M.

    2017-04-01

    Nanocomposite magnets consist of soft and hard ferrite phases are known as an exchange spring magnet when they are sufficiently spin exchange coupled. Hard and soft ferrites offer high value of coercivity, Hc and saturation magnetization, Ms respectively. In order to obtain a better permanent magnet, both soft and hard ferrite phases need to be ;exchange coupled;. The nanoparticles were prepared by a simple one-pot technique of 80% soft phase and 20% hard phase. This technique involves a single reaction mixture of metal nitrates and aqueous solution of varied amounts of polyvinylpyrrolidone (PVP). The heat treatment applied was at 800 °C for 3 h. The synthesized composites were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infra-red (FT-IR), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM). The coexistence of two phases, Ni0.5Zn0.5Fe2O4 and SrFe12O19 were observed by XRD patterns. It also verified by the EDX that no impurities detected. The magnetic properties of nanocomposite ferrites for 0.06 g/ml PVP gives a better properties of Hc 932 G and Ms 39.0 emu/g with average particle size obtained from FESEM was 49.2 nm. The concentration of PVP used gives effect on the magnetic properties of the samples.

  17. Surface spin disorder and spin-glass-like behaviour in manganese-substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Topkaya, R.; Akman, Ö.; Kazan, S.; Aktaş, B.; Durmus, Z.; Baykal, A.

    2012-10-01

    Manganese-substituted cobalt ferrite nanoparticles coated with triethylene glycol (TREG) have been prepared by the glycothermal reaction. The effect of Mn substitution and coating on temperature-dependent magnetic properties of the TREG-coated Mn x Co1- x Fe2O4 nanoparticles (0.0 ≤ x ≤ 0.8) with size of 5-7 nm has been investigated in the temperature range of 10-300 K in a magnetic field up to 9 T. After the irreversible processes of the magnetic hysteresis curves were completed, the high-field regions of these curves were fitted by using a `law of approach to saturation' to extract the magnetic properties, such as the effective anisotropy constant ( K eff) and the anisotropy field ( H A) etc. High coercive field of 12.6 kOe is observed in pure cobalt ferrite coated with TREG at 10 K. The low temperature unsaturated magnetization behaviour indicates the core-shell structure of the Mn x Co1- x Fe2O4 NPs. Zero-field-cooled (ZFC) and field-cooled (FC) measurements revealed superparamagnetic phase of TREG-coated Mn x Co1- x Fe2O4 nanoparticles at room temperature. The blocking and irreversibility temperatures obtained from ZFC-FC curves decrease at highest Mn concentration ( x = 0.8). The existence of spin-glass-like surface layer with freezing temperature of 215 K was established with the applied field dependence of the blocking temperatures following the de Almeida-Thouless line for the Mn0.6Co0.4Fe2O4 NPs. The shifted hysteresis loops with exchange bias field of 60 Oe and high-field irreversibility up to 60 kOe in FC M- H curve at 10 K show that spin-glass-like surface spins surrounds around ordered core material of the Mn0.6Co0.4Fe2O4 NPs. FMR measurement show that all the TREG-coated Mn x Co1- x Fe2O4 nanoparticles absorb microwave in broad field range of about ten thousands Oe. The spectra for all the samples have broad linewidth because of angular distributions of easy axis and internal fields of nanoparticles.

  18. Structure and magnetic properties of rf thermally plasma synthesized Mn and Mn-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Son, S.; Swaminathan, R.; McHenry, M. E.

    2003-05-01

    Plasma synthesis has previously been shown to be a viable route to producing nanocrystalline magnetite and Ni ferrite nanoparticles. In this work nanocrystalline powders of Mn and Mn-Zn ferrites have been synthesized using a 50 kW-3 MHz rf (radio frequency) induction plasma torch. We investigate these materials for soft magnetic applications. High-energy ball milled Mn + Fe powders and (Mn+Zn) +Fe powders (<10 μm) in the stoichiometric ratio of 1:2 were used as precursors for the ferrite synthesis. Compressed air was used in the oxygen source for oxidation of metal species in the plasma. X-ray diffraction patterns for the plasma-torched Mn ferrite and MnZn ferrite powders were indexed to the spinel ferrite crystal structure. An average grain size of ˜20 nm was determined from Scherrer analysis confirmed by transmission electron microscopy studies. The particles also exhibited faceted polygonal growth forms with the associated truncated cuboctahedral shapes. Room-temperature vibrating sample magnetometer measurements of the hysteretic response revealed saturation magnetization Ms and coercivity Hc of Mn ferrite are 23.65 emu/g and 20 Oe, respectively. The Néel temperatures of Mn ferrite powders before and after annealing (500 °C, 30 min) were determined to be 200 and 360 °C, respectively. Inductively coupled plasma chemical analysis and energy dispersive x-ray analysis data on the plasma-torched powders indicated deviations in the Mn or Zn contents than the ideal stoichiometry. MnZn ferrite was observed to have a Néel temperature increased by almost 400 °C as compared with as-synthesized Mn ferrite but with a larger coercivity of ˜35 Oe.

  19. Development of europium doped core-shell silica cobalt ferrite functionalized nanoparticles for magnetic resonance imaging.

    PubMed

    Kevadiya, Bhavesh D; Bade, Aditya N; Woldstad, Christopher; Edagwa, Benson J; McMillan, JoEllyn M; Sajja, Balasrinivasa R; Boska, Michael D; Gendelman, Howard E

    2017-02-01

    The size, shape and chemical composition of europium (Eu(3+)) cobalt ferrite (CFEu) nanoparticles were optimized for use as a "multimodal imaging nanoprobe" for combined fluorescence and magnetic resonance bioimaging. Doping Eu(3+) ions into a CF structure imparts unique bioimaging and magnetic properties to the nanostructure that can be used for real-time screening of targeted nanoformulations for tissue biodistribution assessment. The CFEu nanoparticles (size ∼7.2nm) were prepared by solvothermal techniques and encapsulated into poloxamer 407-coated mesoporous silica (Si-P407) to form superparamagnetic monodisperse Si-CFEu nanoparticles with a size of ∼140nm. Folic acid (FA) nanoparticle decoration (FA-Si-CFEu, size ∼140nm) facilitated monocyte-derived macrophage (MDM) targeting. FA-Si-CFEu MDM uptake and retention was higher than seen with Si-CFEu nanoparticles. The transverse relaxivity of both Si-CFEu and FA-Si-CFEu particles were r2=433.42mM(-1)s(-1) and r2=419.52mM(-1)s(-1) (in saline) and r2=736.57mM(-1)s(-1) and r2=814.41mM(-1)s(-1) (in MDM), respectively. The results were greater than a log order-of-magnitude than what was observed at replicate iron concentrations for ultrasmall superparamagnetic iron oxide (USPIO) particles (r2=31.15mM(-1)s(-1) in saline) and paralleled data sets obtained for T2 magnetic resonance imaging. We now provide a developmental opportunity to employ these novel particles for theranostic drug distribution and efficacy evaluations.

  20. Yafet-Kittel-type magnetic order in Zn-substituted cobalt ferrite nanoparticles with uniaxial anisotropy

    NASA Astrophysics Data System (ADS)

    Topkaya, R.; Baykal, A.; Demir, A.

    2013-01-01

    Zn-substituted cobalt ferrite (Zn x Co1- x Fe2O4 with 0.0 ≤ x ≤ 1.0) nanoparticles coated with triethylene glycol (TREG) were prepared by the hydrothermal technique. The effect of Zn substitution on temperature-dependent magnetic properties of the TREG-coated Zn x Co1- x Fe2O4 nanoparticles has been investigated in the temperature range of 10-400 K and in magnetic fields up to 9 T. The structural, morphological, and magnetic properties of TREG-coated Zn x Co1- x Fe2O4 NPs were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The average crystallite size estimated from X-ray line profile fitting was found to be in the range of 7.0-10 nm. The lattice constant determined using the Nelson-Riley extrapolation method continuously increases with the increase in Zn2+ content, obeying Vegard's law. TEM analysis revealed that the synthesized particles were nearly monodisperse, roughly spherical shaped nanoparticles in the size range of 9.0-15 nm. FT-IR spectra confirm that TREG is successfully coated on the surface of nanoparticles (NPs). The substitution of non-magnetic Zn2+ ions for magnetic Co2+ ions substantially changes the magnetic properties of the TREG-coated Zn x Co1- x Fe2O4 NPs. The saturation magnetization and the experimental magnetic moment are observed to initially increase (up to x = 0.2), which is explained by Néel's collinear two-sublattice model, and then continuously decrease with further increase in Zn content x. This decrease obeys the three-sublattice model suggested by Yafet-Kittel (Y-K). While the Y-K angle is zero for the CoFe2O4 NPs coated with TREG, it increases gradually with increasing Zn concentrations and extrapolates to 82.36° for ZnFe2O4 NPs coated with TREG. The increase in spin canting angles (Y-K angles) suggests the existence of triangular (or canted) spin arrangements in all the samples (except for the samples with x

  1. Preparation and investigation of dc conductivity and relative permeability of epoxy/Li-Ni-Zn ferrite composites

    NASA Astrophysics Data System (ADS)

    Darwish, M. A.; Saafan, S. A.; El-Kony, D.; Salahuddin, N. A.

    2015-07-01

    Ferrite nanoparticles - having the compositions Li(x/2)(Ni0.5Zn0.5)(1-x)Fe(2+x/2)O4 (x=0, 0.2, 0.3) - have been prepared by the co-precipitation method. The prepared powders have been divided into groups and sintered at different temperatures (373 K, 1074 K and 1473 K). X-Ray diffraction analysis (XRD) for all samples has confirmed the formation of the desired ferrites with crystallite sizes within the nanoscale (<100 nm). The dc conductivity, the relative permeability and the magnetization of the ferrite samples have been investigated and according to the results, the sample Li0.15(Ni0.5Zn0.5)0.7 Fe2.15O4 sintered at 1473 K has been chosen to prepare the composites. The particle size of this sample has been recalculated by using JEOL JEM-100SX transmission electron microscope and it has been found about 64.7 nm. Then, a pure epoxy sample and four pristine epoxy resin /Li0.15(Ni0.5Zn0.5)0.7 Fe2.15O4 composites have been prepared using different ferrite contents (20%, 30%, 40%, and 50%) wt.%. These samples have been characterized by Fourier transform infrared (FTIR) spectroscopy and their dc conductivity, relative permeability and magnetization have also been investigated. The obtained results indicate that the investigated composites may be promising candidates for practical applications such as EMI suppressor and high frequency applications.

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

    SciTech Connect

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

    2014-09-08

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

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

    SciTech Connect

    Mahmoodi, Niyaz Mohammad

    2013-10-15

    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.

  4. The superspin glass transition in zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kaman, O.; Kořínková, T.; Jirák, Z.; Maryško, M.; Veverka, M.

    2015-05-01

    Nanoparticles of the ZnxFe3-xO4 (x = 0.3-0.4) spinel phase having 5 and 15 nm size were synthesized by thermal decomposition of the respective acetylacetonates in a high boiling-point solvent employing surfactants. The collective behaviour of the nanoparticles was probed by dc and ac magnetic measurements of tightly compressed pellets of the particles and silica coated products which were prepared by reverse microemulsion technique. The assembly of bare 5 nm particles remains in the superparamagnetic state with Curie-Weiss characteristics down to 35 K when a rather sharp freezing of superspins is detected. The larger particles show a similar but more diffusive transition at 250 K. The cores encapsulated into the diamagnetic silica do not exhibit glassy freezing.

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

    PubMed

    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 E M; Arbab, Ismail Adam; Al-Asbahi, Bandar A; Webster, Thomas J; El Zowalaty, Mohamed Ezzat

    2013-01-01

    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.

  6. New approach for understanding experimental NMR relaxivity properties of magnetic nanoparticles: focus on cobalt ferrite.

    PubMed

    Rollet, Anne-Laure; Neveu, Sophie; Porion, Patrice; Dupuis, Vincent; Cherrak, Nadine; Levitz, Pierre

    2016-12-07

    Relaxivities r1 and r2 of cobalt ferrite magnetic nanoparticles (MNPs) have been investigated in the aim of improving the models of NMR relaxation induced by magnetic nanoparticles. On one hand a large set of relaxivity data has been collected for cobalt ferrite MNP dispersions. On the other hand the relaxivity has been calculated for dispersions of cobalt ferrite MNPs with size ranging from 5 to 13 nm, without using any fitting procedure. The model is based on the magnetic dipolar interaction between the magnetic moments of the MNPs and the (1)H nuclei. It takes into account both the longitudinal and transversal contributions of the magnetic moments of MNPs leading to three contributions in the relaxation equations. The comparison of the experimental and theoretical data shows a good agreement of the NMR profiles as well as the temperature dependence.

  7. Investigations on Cu2+-substituted Ni-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Amarjeet; Kumar, Vinod

    2016-11-01

    CuxNi(1-x)/2Zn(1-x)/2Fe2O4 (x = 0.1, 0.3 and 0.5) nanoparticles were prepared by chemical co-precipitation method. The developed nanoparticles were characterized for structural properties by powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Peak position in the X-ray diffraction pattern confirmed the single spinel phase of the developed particles. Infrared (IR) spectroscopy in mid-IR range showed the presence of characteristic absorption bands corresponding to octahedral and tetrahedral bonds in the spinel structure of prepared samples. Thermo-gravimetric analysis (TGA) measurements showed a considerable weight loss in the developed samples above 700∘C. Frequency dependence of the electrical properties of the developed material pellets was studied in the frequency range of 1 kHz-5 MHz. Temperature dependence of the dielectric constant of Cu0.1Ni0.45Zn0.45Fe2O4 was studied at different temperatures, i.e. at 425, 450 and 475 K, in the frequency range of 1 kHz-5 MHz. It was found that the electrical conductivity decreases with increasing Cu2+ ion content while it increases with the increase in temperature.

  8. Comparison of catalytic activity of bismuth substituted cobalt ferrite nanoparticles synthesized by combustion and co-precipitation method

    NASA Astrophysics Data System (ADS)

    Kiran, Venkat Savunthari; Sumathi, Shanmugam

    2017-01-01

    In this study, cobalt ferrite and bismuth substituted cobalt ferrite (CoFe2-xBixO4x=0, 0.1) nanoparticles were synthesized by two different methods viz combustion and co-precipitation. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy-energy dispersive X-ray analyzer (SEM-EDX) and vibrating sample magnetometer (VSM). The results of powder XRD pattern showed an increase in lattice parameter and decrease in particle size of cobalt ferrite by the substitution of bismuth. Catalytic activity of cobalt ferrite and bismuth substituted cobalt ferrite nanoparticles synthesized by two different methods were compared for the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a reducing agent.

  9. Magnesium-zinc ferrite nanoparticles: effect of copper doping on the structural, electrical and magnetic properties.

    PubMed

    Zaki, H M; Al-Heniti, S; Umar, Ahmad; Al-Marzouki, F; Abdel-Daiem, A; Elmosalami, T A; Dawoud, H A; Al-Hazmi, F S; Ata-Allah, S S

    2013-06-01

    In this paper, Mg0.5Zn0.5-Cu(x)Fe2O4 ferrites nanoparticles were synthesized by facile co-precipitation route and characterized in detail in terms of their structural, electrical and magnetic properties as a function of Cu concentration. The prepared samples have cubic spinel phase as confirmed by X-ray diffraction patterns. The decrease of the lattice constant and increase of X-ray density indicate the solubility of Cu ions in the spinel lattice. The AC conductivity measurements between 300 K and 773 K at different frequencies 1 KHz up to 1 MHz, showed two different behaviors as semiconductor-like at high temperature and frequency depending behavior associated with dispersion phenomena at low temperatures. The conduction mechanism in the system is influenced by Cu concentration and the dominant one is the hopping conduction mechanism. Dielectric measurements at the same conditions of temperatures and frequencies exhibited that the dielectric loss increases with increasing the temperature and decreasing the frequency indicating the semiconducting nature of the ferrite compounds. An anomalous behavior of the dielectric loss is observed in samples with high Cu content which explained in terms of resonance between frequency accompanied the electronic hopping and the frequency of the external electric field. The analysis of Mössbauer spectra revealed that copper free compound is super-paramagnetically relaxed in nature and zinc free compound demonstrates ferrimagnetic order. Moreover, hyperfine field spectrum shows the migration of Cu ions from octahedral to tetrahedral site in zinc free compound.

  10. Seeded growth of ferrite nanoparticles from Mn oxides: observation of anomalies in magnetic transitions.

    PubMed

    Song, Hyon-Min; Zink, Jeffrey I; Khashab, Niveen M

    2015-07-28

    A series of magnetically active ferrite nanoparticles (NPs) are prepared by using Mn oxide NPs as seeds. A Verwey transition is identified in Fe3O4 NPs with an average diameter of 14.5 nm at 96 K, where a sharp drop of magnetic susceptibility occurs. In MnFe2O4 NPs, a spin glass-like state is observed with the decrease in magnetization below the blocking temperature due to the disordered spins during the freezing process. From these MnFe2O4 NPs, MnFe2O4@Mn(x)Fe(1-x)O core-shell NPs are prepared by seeded growth. The structure of the core is cubic spinel (Fd3¯m), and the shell is composed of iron-manganese oxide (Mn(x)Fe(1-x)O) with a rock salt structure (Fm3¯m). Moiré fringes appear perpendicular to the 〈110〉 directions on the cubic shape NPs through the plane-matched epitaxial growth. These fringes are due to the difference in the lattice spacings between MnFe2O4 and Mn(x)Fe(1-x)O. Exchange bias is observed in these MnFe2O4@Mn(x)Fe(1-x)O core-shell NPs with an enhanced coercivity, as well as the shift of hysteresis along the field direction.

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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 °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 °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.

  12. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    SciTech Connect

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

    2014-04-24

    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.

  13. Electrical and optical properties of gadolinium doped bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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.

  14. Influence of the magnetic dead layer thickness of Mg-Zn ferrites nanoparticle on their magnetic properties

    NASA Astrophysics Data System (ADS)

    El-Sayed, H. M.; Ali, I. A.; Azzam, A.; Sattar, A. A.

    2017-02-01

    Nanoparticle ferrite with chemical formula Mg(1-x)ZnxFe2O4 (where x=0.0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by sol-gel technique. Single phase structure of these ferrites was confirmed using X-ray diffraction (XRD). Transmission Electron Microscope (TEM) showed that the particle size of the samples in the range of (5.7-10.6 nm). The hysteresis studies showed superparamagnetic behaviour at room temperature. The magnetization behaviour with Zn-content is expressed in the light of Yafet-Kittel angles. The dead layer thickness (t) was calculated and its effect on the magnetization and magnetic losses was debated. The Specific Absorption Rate (SAR) in an alternating magnetic field with frequency 198 kHz for these ferrites has been studied. It is found that, the thickness of magnetic dead layer of the surface of the materials has greatly affected the SAR value of the samples.

  15. Structural and FMR lineshape analysis of Mn Zn-ferrite nanoparticles

    SciTech Connect

    Thirupathi, G.; Singh, R.

    2015-06-24

    The Mn{sub 0.25}Zn{sub 0.75}Fe{sub 2}O{sub 4} (MZF) nanoparticles of 3 to 5 nm size were synthesized by chemical coprecipitation method. The X-ray diffraction (XRD) patterns were well fitted with single phase spinel ferrite structure using Rietveld analysis as Fd-3m space group. The ferromagnetic resonance (FMR) spectra of MZF nanoparticles becomes more asymmetric with increase in particle size from 3 to 5 nm. The change in FMR line shape is attributed to the increase in ferromagnetic interactions and anisotropy in the system with increase in nanoparticles size. The decrease in total absorption of the FMR line with decreasing temperature at low temperatures indicates weak antiferromagnetic coupling between the octahedral and tetrahedral sublattices of the spinel ferrite system.

  16. Phase controlled synthesis of (Mg, Ca, Ba)-ferrite magnetic nanoparticles with high uniformity

    NASA Astrophysics Data System (ADS)

    Wang, S. F.; Li, Q.; Zu, X. T.; Xiang, X.; Liu, W.; Li, S.

    2016-12-01

    (Mg, Ca, Ba)-ferrite magnetic nanoparticles were successfully synthesized through modifying the atomic ratio of polysaccharide and chelating agent at an optimal sintering temperature. In the process, the polysaccharide plays an important role in drastically shrinking the precursor during the gel drying process. In the metal-complex structure, M2+ ion active sites were coordinated by -OH of the water molecules except for EDTA anions. The MFe2O4 magnetic nanoparticles exhibited enhanced magnetic properties when compared with nano-MFe2O4 of similar particle size synthesized by other synthesis route reported in the literature. In particular, the sintering temperature improves the crystallinity and increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles significantly.

  17. Chemical methodologies for preparation of micron and nanometer scale ferrites--a mini review of patents.

    PubMed

    Pant, Prita; Bhuvaneswari, Sundararaman; Ghosh, Narendra Nath

    2008-01-01

    Ferrites, with wide range of chemical compositions, have been studied extensively over the years as they have a plethora of applications such as magnetic read/write heads, transformer cores, antennas, microwave absorbers, deflecting yoke, high frequency transformers, catalysis, pigments etc. Particles of submicron size have attracted the attention of scientists and technologists in different fields because they exhibit many unique physical properties as compared to those of bulk materials and are in great demand. Traditional high temperature solid-state method for preparation of ferrites is associated with several limitations. The quest for synthesis of ultrafine ferrite materials has led to the development of various preparative methods. Several patents disclose different wet chemical techniques namely sol-gel, coprecipitation, hydrothermal, combustion, spray pyrolysis etc for preparation of variety of ferrites for wide range of applications. In this mini-review, several patented chemical methods have been discussed critically with specific examples along with the effect of synthetic routes on particle size formation. Applications of ferrite powders with different compositions prepared by the above mentioned patented methods have also been discussed in this review.

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

    PubMed

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

    2013-10-22

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

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

    SciTech Connect

    Hsiung, L; Fluss, M; Kimura, A

    2010-04-06

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

  20. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5

    PubMed Central

    Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João ARG; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

    2016-01-01

    Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity. PMID:27563243

  1. The intrinsic antimicrobial activity of citric acid-coated manganese ferrite nanoparticles is enhanced after conjugation with the antifungal peptide Cm-p5.

    PubMed

    Lopez-Abarrategui, Carlos; Figueroa-Espi, Viviana; Lugo-Alvarez, Maria B; Pereira, Caroline D; Garay, Hilda; Barbosa, João Arg; Falcão, Rosana; Jiménez-Hernández, Linnavel; Estévez-Hernández, Osvaldo; Reguera, Edilso; Franco, Octavio L; Dias, Simoni C; Otero-Gonzalez, Anselmo J

    2016-01-01

    Diseases caused by bacterial and fungal pathogens are among the major health problems in the world. Newer antimicrobial therapies based on novel molecules urgently need to be developed, and this includes the antimicrobial peptides. In spite of the potential of antimicrobial peptides, very few of them were able to be successfully developed into therapeutics. The major problems they present are molecule stability, toxicity in host cells, and production costs. A novel strategy to overcome these obstacles is conjugation to nanomaterial preparations. The antimicrobial activity of different types of nanoparticles has been previously demonstrated. Specifically, magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The citric acid-modified manganese ferrite nanoparticles used in this study were characterized by high-resolution transmission electron microscopy, which confirmed the formation of nanocrystals of approximately 5 nm diameter. These nanoparticles were able to inhibit Candida albicans growth in vitro. The minimal inhibitory concentration was 250 µg/mL. However, the nanoparticles were not capable of inhibiting Gram-negative bacteria (Escherichia coli) or Gram-positive bacteria (Staphylococcus aureus). Finally, an antifungal peptide (Cm-p5) from the sea animal Cenchritis muricatus (Gastropoda: Littorinidae) was conjugated to the modified manganese ferrite nanoparticles. The antifungal activity of the conjugated nanoparticles was higher than their bulk counterparts, showing a minimal inhibitory concentration of 100 µg/mL. This conjugate proved to be nontoxic to a macrophage cell line at concentrations that showed antimicrobial activity.

  2. Structural and magnetic studies of the nickel doped CoFe2O4 ferrite nanoparticles synthesized by the chemical co-precipitation method

    NASA Astrophysics Data System (ADS)

    Kumar, Ashok; Yadav, Nisha; Rana, Dinesh S.; Kumar, Parmod; Arora, Manju; Pant, R. P.

    2015-11-01

    The physical properties of nickel doped cobalt ferrite nanoparticles NixCo1-xFe2O4 (x=0.5, 0.75, 0.9) derived by the chemical co-precipitation route are characterized by XRD, FTIR, TEM, EPR, search coil and ac susceptibility techniques to develop stable kerosene based ferrofluid. XRD patterns and TEM images confirm the single phase formation of NixCo1-xFe2O4 nanoparticles whose crystallite size increases and lattice parameters decreases with the increase in Ni content. EPR resonance signal peak-to-peak line width and resonance field value decreases with the increase in Ni concentration in these samples. The broad nature of resonance signal is attributed to the ferromagnetic nature of the as-prepared nanoparticles and the increase in super exchange interaction among Ni2+-O-Co2+ facilitate the shifting of resonance value to lower field. The hysteresis loops of these nickel doped cobalt ferrite analogs exhibits highly magnetic nature of these nanoparticles at ambient temperature whose saturation magnetization, coerecivity and remanence magnetization decreases linearly with the increase in Ni-concentration in cobalt ferrite. The magnetic susceptibility with temperature curve shows increasing trend of blocking temperature with rise in nickel ion concentration.

  3. Manifestation of weak ferromagnetism and photocatalytic activity in bismuth ferrite nanoparticles

    SciTech Connect

    Sakar, M.; Balakumar, S.; Saravanan, P.; Jaisankar, S. N.

    2013-02-05

    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.

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

    SciTech Connect

    Nongjai, Razia; Batoo, Khalid Mujasam; Khan, Shakeel

    2010-12-01

    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.

  5. Characterization of Ni ferrites powders prepared by plasma arc discharge process

    NASA Astrophysics Data System (ADS)

    Safari, A.; Gheisari, Kh.; Farbod, M.

    2017-01-01

    The aim of this work was to synthesize a single-phase spinel structure from a mixture of zinc, iron and nickel powders by plasma arc discharge method. A mixture of zinc, iron and nickel powders with the appropriate molar ratio was prepared and formed into a cylindrical shape. The synthesis process was performed in air, oxygen and argon atmospheres with the applied arc current of 400 A and pressure of 1 atm. After establishing an arc between the electrodes, the produced powders were collected and their structure and magnetic properties were examined by XRD and VSM, respectively. ZnO as an impurity was appeared in the as-produced powders owing to the high reactivity of zinc atoms, preventing the formation of Ni-Zn ferrite. A pure spinel structure with the highest saturation magnetization (43.8 emu/g) was observed as zinc powders removed completely from the initial mixture. Morphological evaluations using field emission scanning electron microscopy showed that the mean size of fabricated nanoparticles was in the range 100-200 nm and was dependent on the production conditions.

  6. Laccase immobilized manganese ferrite nanoparticle: synthesis and LSSVM intelligent modeling of decolorization.

    PubMed

    Mahmoodi, Niyaz Mohammad; Arabloo, Milad; Abdi, Jafar

    2014-12-15

    Laccase was immobilized onto manganese ferrite nanoparticle (MFN) and dye decolorization from single and binary systems was studied. The characteristics of laccase immobilized manganese ferrite nanoparticle (LIMFN) were investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct red 31 (DR31), Acid blue 92 (AB92) and Direct green 6 (DG6) were used. A least square support vector machine (LSSVM) was developed to predict the decolorization efficiency of various single and binary systems based on the obtained laboratory data under different experimental conditions. Statistical and graphical quality measures were also employed to evaluate the performance and accuracy of the developed intelligent models. It is shown that the predictions of the designed LSSVM models are in close agreement with the experimental data. The effects of LIMFN dosage, pH and dye concentration on dye decolorization from single and binary systems were evaluated. Decolorization kinetics followed Michaelis-Menten Model.

  7. Calcium-assisted reduction of cobalt ferrite nanoparticles for nanostructured iron cobalt with enhanced magnetic performance

    NASA Astrophysics Data System (ADS)

    Qi, B.; Andrew, J. S.; Arnold, D. P.

    2017-03-01

    This paper demonstrates the potential of a calcium-assisted reduction process for synthesizing fine-grain ( 100 nm) metal alloys from metal oxide nanoparticles. To demonstrate the process, an iron cobalt alloy (Fe66Co34) is obtained by hydrogen annealing 7-nm cobalt ferrite (CoFe2O4) nanoparticles in the presence of calcium granules. The calcium serves as a strong reducing agent, promoting the phase transition from cobalt ferrite to a metallic iron cobalt alloy, while maintaining high crystallinity. Magnetic measurements demonstrate the annealing temperature is the dominant factor of tuning the grain size and magnetic properties. Annealing at 700 °C for 1 h maximizes the magnetic saturation, up to 2.4 T (235 emu/g), which matches that of bulk iron cobalt.

  8. Inter-particle interactions and magnetism in manganese-zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Poddar, P.; Srikanth, H.; Morrison, S. A.; Carpenter, E. E.

    2005-03-01

    Manganese-zinc ferrite (Mn xZn 1-xFe 2O 4) nanoparticles were synthesized by reverse micelle technique using two different surfactant media—(1) bis-(2-ethylhexl) sodium sulfosuccinate (AOT) and (2) mix of nonylphenol poly(oxyethylene) 5 and nonylphenol poly(oxyethylene) 9 (NP) followed by annealing of precursors to remove the surfactant coating and to obtain better crystalline phase. A comparison of the magnetic properties showed distinct differences in blocking temperature, coercivity and saturation magnetization. Radio-frequency (RF) transverse susceptibility (TS) measurements were in agreement with the static magnetization data. Our precise TS measurements further revealed features associated with anisotropy fields that were dependent on the grain size, crystallinity and inter-particle interactions. Overall, we have demonstrated that RF TS is an excellent probe of the dynamic magnetization and influence of effects such as crystallinity and inter-particle interactions in soft ferrite nanoparticles.

  9. Magnetic properties of nanocomposites based on opal matrices with embedded ferrite-spinel nanoparticles

    NASA Astrophysics Data System (ADS)

    Rinkevich, A. B.; Korolev, A. V.; Samoylovich, M. I.; Klescheva, S. M.; Perov, D. V.

    2016-02-01

    Magnetic properties of nanocomposites based on opal matrices with ferrite-spinel nanoparticles embedded have been investigated in temperature range from 2 to 300 K. The magnetization curves and hysteresis loops as well as the temperature dependence of magnetic moment and the temperature and frequency dependences of AC susceptibility have been measured. The results of magnetic measurements are compared to X-ray analysis and electron microscopy investigations.

  10. Synthesis of Water Dispersible and Catalytically Active Gold-Decorated Cobalt Ferrite Nanoparticles.

    PubMed

    Silvestri, Alessandro; Mondini, Sara; Marelli, Marcello; Pifferi, Valentina; Falciola, Luigi; Ponti, Alessandro; Ferretti, Anna Maria; Polito, Laura

    2016-07-19

    Hetero-nanoparticles represent an important family of composite nanomaterials that in the past years are attracting ever-growing interest. Here, we report a new strategy for the synthesis of water dispersible cobalt ferrite nanoparticles (CoxFe3-xO4 NPs) decorated with ultrasmall (2-3 nm) gold nanoparticles (Au NPs). The synthetic procedure is based on the use of 2,3-meso-dimercaptosuccinic acid (DMSA), which plays a double role. First, it transfers cobalt ferrite NPs from the organic phase to aqueous media. Second, the DMSA reductive power promotes the in situ nucleation of gold NPs in proximity of the magnetic NP surface. Following this procedure, we achieved a water dispersible nanosystem (CoxFe3-xO4-DMSA-Au NPs) which combines the cobalt ferrite magnetic properties with the catalytic features of ultrasmall Au NPs. We showed that CoxFe3-xO4-DMSA-Au NPs act as an efficient nanocatalyst to reduce 4-nitrophenol to 4-aminophenol and that they can be magnetically recovered and recycled. It is noteworthy that such nanosystem is more catalytically active than Au NPs with equal size. Finally, a complete structural and chemical characterization of the hetero-NPs is provided.

  11. Synthesis of Ferrite Nickel Nano-particles and Its Role as a p-Dopant in the Improvement of Hole Injection of an Organic Light-Emitting Diode

    NASA Astrophysics Data System (ADS)

    Noori, Maryam; Jafari, Mohammad Reza; Hosseini, Sayed Mohsen; Shahedi, Zahra

    2017-02-01

    We fabricated an organometallic complex based on zinc ions using zinc complex as a fluorescent in organic light-emitting diodes (OLEDs). Also, the nano-particles of ferrite nickel were produced in a simple aqueous system prepared by mixing Ni (NO3)2, Fe (NO3)3 and deionized water solutions. The synthesized zinc bis (8-hydroxyquinoline) (Znq2) complex and NiFe2O4 nano-particles were characterized by using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) as well as photoluminescence spectroscopy analysis. Their energy level was also determined by some cyclic voltammetry (CV) measurements. The maximum green photoluminescence was observed at 565 nm. The nano-particles of ferrite nickel were utilized in preparation of OLEDs by blending of the magnetic nano-particles with PEDOT:PSS and Zn-complex solutions. The electrical and optical performance of prepared OLEDs with/without doped nano-particle was studied. The samples were configured into two structures: (1) Indium Tin Oxide (ITO)/ poly(3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/Znq2/(2-4-biphenylyl)-5-phenyl-oxadiazole (PBD)/aluminum (Al) and (2) ITO/PEDOT:PSS:NiFe2O4(NPs)/Znq2/PBD/Al. Obtained results showed that the current density and electroluminescence efficiency were increased and the turn-on voltage decreased (about 3 V) by using nano-particles into a PEDOT:PSS layer (Hole transport layer). Also, the electroluminescence efficiency was decreased by incorporating magnetic nano-particles into a Zn-complex layer (emissive layer). It was found that utilizing NiFe2O4 nano-particles caused an increase of hole-injection layer conductivity effectively and a decrease of the turn-on voltage.

  12. Formation and microwave absorption of barium and strontium ferrite prepared by sol-gel technique

    NASA Astrophysics Data System (ADS)

    Sürig, C.; Hempel, K. A.; Bonnenberg, D.

    1993-11-01

    Ba and Sr ferrites are prepared by sol-gel technique with different Fe/Ba(Sr) ratios in the starting materials. Magnetization, coercive, and anisotropy field strength are determined depending on the heat treatment of the gel and the iron/barium(strontium) ratio in the starting material. A two-step heat treatment is used to prepare single-domain powders with high magnetization. These powders prepared by sol-gel technique show single-domain behavior with specific magnetization σS=649 A cm2/g and coercive field strength HcM=402 kA/m in the case of Ba ferrite and σS=695 A cm2/g and HcM=416 kA/m for Sr the ferrite. Al-substituted ferrites with high anisotropy field strengths are prepared additionally. Ferromagnetic resonance absorption is used to determine the anisotropy field strength and to investigate the formation process of the hexaferrite phase during the heat treatment. The beginning of hexaferrite formation occurs at annealing temperatures below 700 °C.

  13. Structural and magnetic properties of cobalt-doped iron oxide nanoparticles prepared by solution combustion method for biomedical applications.

    PubMed

    Venkatesan, Kaliyamoorthy; Rajan Babu, Dhanakotti; Kavya Bai, Mane Prabhu; Supriya, Ravi; Vidya, Radhakrishnan; Madeswaran, Saminathan; Anandan, Pandurangan; Arivanandhan, Mukannan; Hayakawa, Yasuhiro

    2015-01-01

    Cobalt-doped iron oxide nanoparticles were prepared by solution combustion technique. The structural and magnetic properties of the prepared samples were also investigated. The average crystallite size of cobalt ferrite (CoFe2O4) magnetic nanoparticle was calculated using Scherrer equation, and it was found to be 16±5 nm. The particle size was measured by transmission electron microscope. This value was found to match with the crystallite size calculated by Scherrer equation corresponding to the prominent intensity peak (311) of X-ray diffraction. The high-resolution transmission electron microscope image shows clear lattice fringes and high crystallinity of cobalt ferrite magnetic nanoparticles. The synthesized magnetic nanoparticles exhibited the saturation magnetization value of 47 emu/g and coercivity of 947 Oe. The anti-microbial activity of cobalt ferrite nanoparticles showed better results as an anti-bacterial agent. The affinity constant was determined for the nanoparticles, and the cytotoxicity studies were conducted for the cobalt ferrite nanoparticles at different concentrations and the results are discussed.

  14. Structural and magnetic properties of cobalt-doped iron oxide nanoparticles prepared by solution combustion method for biomedical applications

    PubMed Central

    Venkatesan, Kaliyamoorthy; Rajan Babu, Dhanakotti; Kavya Bai, Mane Prabhu; Supriya, Ravi; Vidya, Radhakrishnan; Madeswaran, Saminathan; Anandan, Pandurangan; Arivanandhan, Mukannan; Hayakawa, Yasuhiro

    2015-01-01

    Cobalt-doped iron oxide nanoparticles were prepared by solution combustion technique. The structural and magnetic properties of the prepared samples were also investigated. The average crystallite size of cobalt ferrite (CoFe2O4) magnetic nanoparticle was calculated using Scherrer equation, and it was found to be 16±5 nm. The particle size was measured by transmission electron microscope. This value was found to match with the crystallite size calculated by Scherrer equation corresponding to the prominent intensity peak (311) of X-ray diffraction. The high-resolution transmission electron microscope image shows clear lattice fringes and high crystallinity of cobalt ferrite magnetic nanoparticles. The synthesized magnetic nanoparticles exhibited the saturation magnetization value of 47 emu/g and coercivity of 947 Oe. The anti-microbial activity of cobalt ferrite nanoparticles showed better results as an anti-bacterial agent. The affinity constant was determined for the nanoparticles, and the cytotoxicity studies were conducted for the cobalt ferrite nanoparticles at different concentrations and the results are discussed. PMID:26491320

  15. Comparative cytotoxic response of nickel ferrite nanoparticles in human liver HepG2 and breast MFC-7 cancer cells.

    PubMed

    Ahamed, Maqusood; Akhtar, Mohd Javed; Alhadlaq, Hisham A; Khan, M A Majeed; Alrokayan, Salman A

    2015-09-01

    Nickel ferrite nanoparticles (NPs) have received much attention for their potential applications in biomedical fields such as magnetic resonance imaging, drug delivery and cancer hyperthermia. However, little is known about the toxicity of nickel ferrite NPs at the cellular and molecular levels. In this study, we investigated the cytotoxic responses of nickel ferrite NPs in two different types of human cells (i.e., liver HepG2 and breast MCF-7). Nickel ferrite NPs induced dose-dependent cytotoxicity in both types of cells, which was demonstrated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazoliumbromide (MTT), neutral red uptake (NRU) and lactate dehydrogenase (LDH) assays. Nickel ferrite NPs were also found to induce oxidative stress, which was evident by the depletion of glutathione and the induction of reactive oxygen species (ROS) and lipid peroxidation. The mitochondrial membrane potential due to nickel ferrite NP exposure was also observed. The mRNA levels for the tumor suppressor gene p53 and the apoptotic genes bax, CASP3 and CASP9 were up-regulated, while the anti-apoptotic gene bcl-2 was down-regulated following nickel ferrite NP exposure. Furthermore, the activities of apoptotic enzymes (caspase-3 and caspase-9) were also higher in both types of cells treated with nickel ferrite NPs. Cytotoxicity induced by nickel ferrite was efficiently prevented by N-acetyl cysteine (ROS scavenger) treatment, which suggested that oxidative stress might be one of the possible mechanisms of nickel ferrite NP toxicity. We also observed that MCF-7 cells were slightly more susceptible to nickel ferrite NP exposure than HepG2 cells. This study warrants further investigation to explore the potential mechanisms of different cytotoxic responses of nickel ferrite NPs in different cell lines.

  16. Surface-Modified Cobalt Ferrite Nanoparticles for Rapid Capture, Detection, and Removal of Pathogens: a Potential Material for Water Purification.

    PubMed

    Bohara, Raghvendra A; Throat, Nanasaheb D; Mulla, Nayeem A; Pawar, Shivaji H

    2016-12-02

    Enteric infections resulting from the consumption of contaminated drinking water, inadequate supply of water for personal hygiene, and poor sanitation take a heavy toll worldwide, and developing countries are the major sufferers. Consumption of microbiologically contaminated water leads to diseases such as amoebiasis, cholera, shigellosis, typhoid, and viral infections leading to gastroenteritis and hepatitis B. The present investigation deals with the development of effective method to capture and eliminate microbial contamination of water and improve the quality of water and thus decreasing the contaminated waterborne infections. Over the last decade, numerous biomedical applications have emerged for magnetic nanoparticles (MNPs) specifically iron oxide nanoparticles. For the first time, we have explored functionalized cobalt ferrite nanoparticles (NPs) for capture and detection of pathogens. The captured bacterial were separated by using simple magnet. To begin with, the prepared NPs were confirmed for biocompatibility study and further used for their ability to detect the bacteria in solution. For this, standard bacterial concentrations were prepared and used to confirm the ability of these particles to capture and detect the bacteria. The effect of particle concentration, time, and pH has been studied, and the respective results have been discussed. It is observed that the presence of amine group on the surface of NPs shows nonspecific affinity and capability to capture Escherichia coli and Staphylococcus aureus. The possible underlying mechanism is discussed in the present manuscript. Based upon this, the present material can be considered for large-scale bacteria capture in water purification application.

  17. Cobalt Zinc Ferrite Nanoparticles as a Potential Magnetic Resonance Imaging Agent: An In vitro Study

    PubMed Central

    Ghasemian, Zeinab; Shahbazi-Gahrouei, Daryoush; Manouchehri, Sohrab

    2015-01-01

    Background: Magnetic Nanoparticles (MNP) have been used for contrast enhancement in Magnetic Resonance Imaging (MRI). In recent years, research on the use of ferrite nanoparticles in T2 contrast agents has shown a great potential application in MR imaging. In this work, Co0.5Zn0.5Fe2O4 and Co0.5Zn0.5Fe2O4-DMSA magnetic nanoparticles, CZF-MNPs and CZF-MNPs-DMSA, were investigated as MR imaging contrast agents. Methods: Cobalt zinc ferrite nanoparticles and their suitable coating, DMSA, were investigated under in vitro condition. Human prostate cancer cell lines (DU145 and PC3) with bare (uncoated) and coated magnetic nanoparticles were investigated as nano-contrast MR imaging agents. Results: Using T2-weighted MR images identified that signal intensity of bare and coated MNPs was enhanced with increasing concentration of MNPs in water. The values of 1/T2 relaxivity (r2) for bare and coated MNPs were found to be 88.46 and 28.80 (mM−1 s−1), respectively. Conclusion: The results show that bare and coated MNPs are suitable as T2-weighted MR imaging contrast agents. Also, the obtained r2/r1 values (59.3 and 50) for bare and coated MNPs were in agreement with the results of other previous relevant works. PMID:26140183

  18. Catalysts prepared from copper-nickel ferrites for the steam reforming of methanol

    NASA Astrophysics Data System (ADS)

    Huang, Yung-Han; Wang, Sea-Fue; Tsai, An-Pang; Kameoka, Satoshi

    2015-05-01

    In this study, Fe3O4-supported Cu and Ni catalysts are prepared through reduction of Cu-Ni (Ni1-xCuxFe2O4) ferrites. The Cu-Ni ferrites, synthesized using a solid-state reaction method, are reduced at temperatures from 240 °C to 500 °C in a H2 atmosphere. All ferrites are characterized with granular morphology and a smooth particle surface before reduction. For the CuFe2O4, Ni0.5Cu0.5Fe2O4 and NiFe2O4 ferrites reduced at 240, 300, and 400 °C, respectively, nanosized Cu and/or Ni particles (5-32 nm) and mesopores (5-30 nm) are distributed and adhered on the surfaces of Fe3O4 supports. After increasing the reduction temperature of NiFe2O4 ferrite to 500 °C, the Ni particles and mesopores disappear from the Fe3O4 surfaces, which is due to the formation of a Fe-Ni alloy covering on the Fe3O4 surfaces. The CuFe2O4 ferrite after H2 reduction at 240 °C exhibits the highest H2 production rate of 149 ml STP/min g-cat at 360 °C. The existence of Ni content in the Cu-Ni ferrites enhances the reverse water gas shift reaction, and raises the CO selectivity while reducing the CO2 selectivity. Formation of a Fe-Ni alloy exaggerates the trend and poisons the H2 production rate.

  19. Preparation and electrical properties of dense micro-cermets made of nickel ferrite and metallic copper

    NASA Astrophysics Data System (ADS)

    Baco-Carles, Valérie; Pasquet, Isabelle; Laurent, Véronique; Gabriel, Armand; Tailhades, Philippe

    2009-08-01

    Dense micro-cermets made of nickel ferrites and copper micrometric particles were obtained from partial reduction under hydrogenated atmosphere at 350 °C of mixed copper nickel ferrites, and sintering in nitrogen at 980 °C. The small copper particles are homogeneous in size and well dispersed in the spinel oxide matrix. No exudation of copper metal was observed after sintering. The micro-cermets prepared are semi-conducting materials with electrical conductivity lying from 44 to 130 S/cm at 980 °C. Their overall characteristics make them interesting for inert anodes dedicated to aluminium electrolysis in melted cryolite.

  20. Adsorption of Pb(2+) from aqueous solution using spinel ferrite prepared from steel pickling sludge.

    PubMed

    Fang, Binbin; Yan, Yubo; Yang, Yang; Wang, Fenglian; Chu, Zhen; Sun, Xiuyun; Li, Jiansheng; Wang, Lianjun

    2016-01-01

    In this paper, spinel ferrite with high crystallinity and high saturation magnetization was successfully prepared from steel pickling sludge by adding iron source and precipitator in the hydrothermal condition. The obtained spinel ferrite was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), and Zeta potential methods and investigated as an adsorbent for removal of Pb(2+) from aqueous solution. Batch experiments were performed by varying the pH values, contact time, temperature and initial metal concentration. The result of pH impact showed that the adsorption of Pb(2+) was a pH dependent process, and the pH 5.8 ± 0.2 was found to be the optimum condition. The achieved experimental data were analyzed with various kinetic and isotherm models. The kinetic studies revealed that Pb(2+) adsorption onto spinel ferrite followed a pseudo-second order model, and the Langmuir isotherm model provided the perfect fit to the equilibrium experimental data. At different temperatures, the maximum Pb(2+) adsorption capacities calculated from the Langmuir equation were in the range of 126.5-175.4 mg/g, which can be in competition with other adsorbents. The thermodynamic results showed that the spinel ferrite could spontaneously and endothermically adsorb Pb(2+) from aqueous solution. The regeneration studies showed that spinel ferrite could be used five times (removal efficiency (%) >90%) by desorption with HNO3 reagent.

  1. Preparation and Characterization of Zinc-Containing Nickel Gallate Ferrite

    NASA Astrophysics Data System (ADS)

    Hashhash, A.; Imam, N. G.; Ismail, S. M.; Yehia, M.

    2015-10-01

    Polycrystalline Ni1- x Zn x FeGaO4 samples containing different amounts of zinc ( x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized by solid-state reaction. Study of the crystal structure by x-ray diffraction (XRD) revealed peaks typical of a single-phase polycrystalline face-centered cubic structure (FCC). Elemental composition was determined by x-ray fluorescence (XRF) analysis. Fourier-transform infrared (FTIR) spectra contained two absorption bands related to the tetrahedral A and octahedral B sites of the spinel ferrite. Magnetization loops obtained by vibrating sample magnetometry (VSM) indicated that the saturation magnetization, M s, decreased gradually with increasing in Zn content ( x), and that coercivity H c was related to the microstructure of the Zn-doped samples. Mössbauer effect (ME) spectra of the samples were broad and magnetically split for x = 0.0 and 0.1 and quadruple doublets for the other Zn2+ concentrations. The dielectric constant ( ɛ') and dielectric loss tangent (tan δ) were also measured over wide ranges of frequency and temperature by use of the two probe method. The results were explained on the basis of cation-anion-cation and cation-cation interactions through the metal sites in the Ni-Zn-Ga ferrites.

  2. Surface plasmon resonance sensor for detecting of arsenic in aqueous solution using polypyrrole-chitosan-cobalt ferrite nanoparticles composite layer

    NASA Astrophysics Data System (ADS)

    Sadrolhosseini, Amir Reza; Naseri, Mahmoud; Kamari, Halimah Mohamed

    2017-01-01

    The detection and measurement of low concentrations of arsenic (V) are the subjects of intense research interest in chemistry and environmental activity. In this research, a polypyrrole-chitosan/cobalt ferrite nanoparticles composite layer was prepared using an electrodeposition method on a gold-coated glass slide. The composite layer was characterized using field emission scanning electron microscopy, energy-dispersed spectroscopy, atomic force microscopy, and a high surface stylus profilometer. The composite layer was used to detect the arsenic in water, and the sensor limitation was about 0.001 ppm. The composite layer was tested using atomic-force microscopy before and after the detection of arsenic. As a result, the roughness was disoriented, as the arsenic was bound on the surface of the composite layer.

  3. Evidence of reentrant behavior in nanoparticles of ferrite in ferrofluids

    NASA Astrophysics Data System (ADS)

    Zins, D.; Nakatsuka, K.; Gendron, F.; Rivoire, M.

    1999-07-01

    Ferrofluids made up of mixed ferrite particles Mn 1- xZn xFe 2O 4 mono-dispersed in glycerol have been studied by ferromagnetic resonance (FMR) in X band and by magnetization measurements in the temperature range of 3.5-300 K. FMR spectra have been recorded on field-cooled samples. Some features of these spectra are typical of a transition from ferro to spin-glass state, i.e. a reentrant behavior. By taking relaxation into account in the frame of Landau Lifchitz formalism, the freezing temperature Tf=40 K was accurately determined, in good agreement with temperature measurements of the static magnetic susceptibility of field-cooled ferrofluid samples.

  4. Bacterially synthesized ferrite nanoparticles for magnetic hyperthermia applications.

    PubMed

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

    2014-11-07

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

  5. Bacterially synthesized ferrite nanoparticles for magnetic hyperthermia applications

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  6. Studying the effect of Zn-substitution on the magnetic and hyperthermic properties of cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Mameli, V.; Musinu, A.; Ardu, A.; Ennas, G.; Peddis, D.; Niznansky, D.; Sangregorio, C.; Innocenti, C.; Thanh, Nguyen T. K.; Cannas, C.

    2016-05-01

    The possibility to finely control nanostructured cubic ferrites (MIIFe2O4) paves the way to design materials with the desired magnetic properties for specific applications. However, the strict and complex interrelation among the chemical composition, size, polydispersity, shape and surface coating renders their correlation with the magnetic properties not trivial to predict. In this context, this work aims to discuss the magnetic properties and the heating abilities of Zn-substituted cobalt ferrite nanoparticles with different zinc contents (ZnxCo1-xFe2O4 with 0 < x < 0.6), specifically prepared with similar particle sizes (~7 nm) and size distributions having the crystallite size (~6 nm) and capping agent amount of 15%. All samples have high saturation magnetisation (Ms) values at 5 K (>100 emu g-1). The increase in the zinc content up to x = 0.46 in the structure has resulted in an increase of the saturation magnetisation (Ms) at 5 K. High Ms values have also been revealed at room temperature (~90 emu g-1) for both CoFe2O4 and Zn0.30Co0.70Fe2O4 samples and their heating ability has been tested. Despite a similar saturation magnetisation, the specific absorption rate value for the cobalt ferrite is three times higher than the Zn-substituted one. DC magnetometry results were not sufficient to justify these data, the experimental conditions of SAR and static measurements being quite different. The synergic combination of DC with AC magnetometry and 57Fe Mössbauer spectroscopy represents a powerful tool to get new insights into the design of suitable heat mediators for magnetic fluid hyperthermia.The possibility to finely control nanostructured cubic ferrites (MIIFe2O4) paves the way to design materials with the desired magnetic properties for specific applications. However, the strict and complex interrelation among the chemical composition, size, polydispersity, shape and surface coating renders their correlation with the magnetic properties not trivial to predict

  7. The Preparation of Soft Magnetic Composites Based on FeSi and Ferrite Fibers

    NASA Astrophysics Data System (ADS)

    Strečková, Magdaléna; Fáberová, Mária; Bureš, Radovan; Kurek, Pavel

    2016-12-01

    The fields of soft magnetic composites and powder metallurgy technologies have a powerful potential to redesign the way of electric motor preparation, and will continue to grow for years to come. A design of the novel soft microcomposite material composed of spherical FeSi particles and Ni0.3Zn0.7Fe2O4 ferrite nanofibers is reported together with a characterization of basic mechanical and electrical properties. The needle-less electrospinning method was used for a preparation of Ni0.3Zn0.7Fe2O4 ferrite nanofibers, which has a spinel-type crystal structure as verified by XRD and TEM analysis. The dielectric coating was prepared by mixing of nanofibers with glycerol and ethanol because of safe manipulation with fumed fibers and homogeneous distribution of the coating around the FeSi particle surface. The final microcomposite samples were prepared by a combination of the traditional PM compaction technique supplemented with a conventional sintering process of the prepared green compacts. The composition and distribution of the secondary phase formed by the spinel ferrite fibers were examined by SEM. It is demonstrated that the prepared composite material has a tight arrangement without any significant porosity, which manifest itself through superior mechanical properties (high mechanical hardness, Young modulus, and transverse rupture strength) and specific electric resistivity compared to the related composite materials including resin as the organic binder.

  8. Synthesis, Characterization and in Vitro Evaluation of Manganese Ferrite (MnFe2O4) Nanoparticles for Their Biocompatibility with Murine Breast Cancer Cells (4T1).

    PubMed

    Kanagesan, Samikannu; Aziz, Sidek Bin Ab; Hashim, Mansor; Ismail, Ismayadi; Tamilselvan, Subramani; Alitheen, Noorjahan Banu Binti Mohammed; Swamy, Mallappa Kumara; Purna Chandra Rao, Bandaru

    2016-03-11

    Manganese ferrite (MnFe2O4) magnetic nanoparticles were successfully prepared by a sol-gel self-combustion technique using iron nitrate and manganese nitrate, followed by calcination at 150 °C for 24 h. Calcined sample was systematically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and vibrational sample magnetometry (VSM) in order to identify the crystalline phase, functional group, morphology, particle size, shape and magnetic behavior. It was observed that the resultant spinal ferrites obtained at low temperature exhibit single phase, nanoparticle size and good magnetic behavior. The study results have revealed the existence of a potent dose dependent cytotoxic effect of MnFe2O4 nanoparticles against 4T1 cell lines at varying concentrations with IC50 values of 210, 198 and 171 μg/mL after 24 h, 48 h and 72 h of incubation, respectively. Cells exposed to higher concentrations of nanoparticles showed a progressive increase of apoptotic and necrotic activity. Below 125 μg/mL concentration the nanoparticles were biocompatible with 4T1 cells.

  9. Studying the effect of Zn-substitution on the magnetic and hyperthermic properties of cobalt ferrite nanoparticles.

    PubMed

    Mameli, V; Musinu, A; Ardu, A; Ennas, G; Peddis, D; Niznansky, D; Sangregorio, C; Innocenti, C; Thanh, Nguyen T K; Cannas, C

    2016-05-21

    The possibility to finely control nanostructured cubic ferrites (M(II)Fe2O4) paves the way to design materials with the desired magnetic properties for specific applications. However, the strict and complex interrelation among the chemical composition, size, polydispersity, shape and surface coating renders their correlation with the magnetic properties not trivial to predict. In this context, this work aims to discuss the magnetic properties and the heating abilities of Zn-substituted cobalt ferrite nanoparticles with different zinc contents (ZnxCo1-xFe2O4 with 0 < x < 0.6), specifically prepared with similar particle sizes (∼7 nm) and size distributions having the crystallite size (∼6 nm) and capping agent amount of 15%. All samples have high saturation magnetisation (Ms) values at 5 K (>100 emu g(-1)). The increase in the zinc content up to x = 0.46 in the structure has resulted in an increase of the saturation magnetisation (Ms) at 5 K. High Ms values have also been revealed at room temperature (∼90 emu g(-1)) for both CoFe2O4 and Zn0.30Co0.70Fe2O4 samples and their heating ability has been tested. Despite a similar saturation magnetisation, the specific absorption rate value for the cobalt ferrite is three times higher than the Zn-substituted one. DC magnetometry results were not sufficient to justify these data, the experimental conditions of SAR and static measurements being quite different. The synergic combination of DC with AC magnetometry and (57)Fe Mössbauer spectroscopy represents a powerful tool to get new insights into the design of suitable heat mediators for magnetic fluid hyperthermia.

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

    PubMed Central

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

    2014-01-01

    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

  11. Preparation methods of alginate nanoparticles.

    PubMed

    Paques, Jerome P; van der Linden, Erik; van Rijn, Cees J M; Sagis, Leonard M C

    2014-07-01

    This article reviews available methods for the formation of alginate nano-aggregates, nanocapsules and nanospheres. Primarily, alginate nanoparticles are being prepared by two methods. In the "complexation method", complex formation on the interface of an oil droplet is used to form alginate nanocapsules, and complex formation in an aqueous solution is used to form alginate nano-aggregates. In a second method w/o emulsification coupled with gelation of the alginate emulsion droplet can be used to form alginate nanospheres. We review advantages and disadvantages of these methods, and give an overview of the properties of the alginate particles produced with these methods.

  12. The effects of synthesis conditions on the magnetic properties of zinc ferrite spinel nanoparticles

    NASA Astrophysics Data System (ADS)

    El Maalam, K.; Fkhar, L.; Mahhouti, Z.; Mounkachi, O.; AitAli, M.; Hamedoun, M.; Benyoussef, A.

    2016-10-01

    Zinc ferrite nanocrystals were synthesized from metal chloride precursors via chemical co-precipitation method, using different synthesis conditions. Characterization measurements including X-ray diffraction (XRD), transmission electron microscopy (TEM) and super conductiong quantum device (SQUID) were used to study the influence of precursor's concentration and reaction time on the crystalline structure, average sizes and magnetic properties of zinc ferrite nanoparticles. The transmission images show spherical, homogenous shape and particle size ranging from 16 to 22 nm. DC magnetization (2-300 K) measurements reveal a superparamagnetic behavior for the ZnFe2O4 samples with a blocking temperature in the range of 18-24 K. Our results demonstrate that magnetic properties of magnetic particles can be largely modified by just changing the reaction condition such as concentration and reaction time, which might be a useful way to design novel magnetic materials.

  13. Amperometric ascorbic acid sensor based on doped ferrites nanoparticles modified glassy carbon paste electrode.

    PubMed

    Dimitrijević, Teodora; Vulić, Predrag; Manojlović, Dragan; Nikolić, Aleksandar S; Stanković, Dalibor M

    2016-07-01

    In this study, a novel electrochemical sensor for quantification of ascorbic acid with amperometric detection in physiological conditions was constructed. For this purpose, cobalt and nickel ferrites were synthesized using microwave and ultrasound assistance, characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRPD), and used for modification of glassy carbon paste electrode (GCPE). It was shown that introducing these nanoparticles to the structure of GCPE led to increasing analytical performance. Co ferrite modified GCPE (CoFeGCPE) showed better characteristics toward ascorbic acid sensing. The limit of detection (LOD) obtained by sensor was calculated to be 0.0270 mg/L, with linear range from 0.1758 to 2.6010 mg/L. This sensor was successfully applied for practical analysis, and the obtained results demonstrated that the proposed procedure could be a promising replacement for the conventional electrode materials and time-consuming and expensive separation methods.

  14. Enhancement in magnetic properties of magnesium substituted bismuth ferrite nanoparticles

    SciTech Connect

    Xu, Jianlong; Xie, Dan E-mail: RenTL@mail.tsinghua.edu.cn; Teng, Changjiu; Zhang, Xiaowen; Zhang, Cheng; Sun, Yilin; Ren, Tian-Ling E-mail: RenTL@mail.tsinghua.edu.cn; Zeng, Min; Gao, Xingsen; Zhao, Yonggang

    2015-06-14

    We report a potential way to effectively improve the magnetic properties of BiFeO{sub 3} (BFO) nanoparticles through Mg{sup 2+} ion substitution at the Fe-sites of BFO lattice. The high purity and structural changes induced by Mg doping are confirmed by X-ray powder diffractometer and Raman spectra. Enhanced magnetic properties are observed in Mg substituted samples, which simultaneously exhibit ferromagnetic and superparamagnetic properties at room temperature. A physical model is proposed to support the observed ferromagnetism of Mg doped samples, and the superparamagnetic properties are revealed by the temperature dependent magnetization measurements. The improved magnetic properties and soft nature obtained by Mg doping in BFO nanoparticles demonstrate the possibility of BFO nanoparticles to practical applications.

  15. Enhancement in magnetic properties of magnesium substituted bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Xu, Jianlong; Xie, Dan; Teng, Changjiu; Zhang, Xiaowen; Zhang, Cheng; Sun, Yilin; Ren, Tian-Ling; Zeng, Min; Gao, Xingsen; Zhao, Yonggang

    2015-06-01

    We report a potential way to effectively improve the magnetic properties of BiFeO3 (BFO) nanoparticles through Mg2+ ion substitution at the Fe-sites of BFO lattice. The high purity and structural changes induced by Mg doping are confirmed by X-ray powder diffractometer and Raman spectra. Enhanced magnetic properties are observed in Mg substituted samples, which simultaneously exhibit ferromagnetic and superparamagnetic properties at room temperature. A physical model is proposed to support the observed ferromagnetism of Mg doped samples, and the superparamagnetic properties are revealed by the temperature dependent magnetization measurements. The improved magnetic properties and soft nature obtained by Mg doping in BFO nanoparticles demonstrate the possibility of BFO nanoparticles to practical applications.

  16. Correlating size and composition-dependent effects with magnetic, Mössbauer, and pair distribution function measurements in a family of catalytically active ferrite nanoparticles

    DOE PAGES

    Wong, Stanislaus; Papaefthymiou, Georgia C.; Lewis, Crystal S.; ...

    2015-05-06

    The magnetic spinel ferrites, MFe₂O₄ (wherein 'M' = a divalent metal ion such as but not limited to Mn, Co, Zn, and Ni), represent a unique class of magnetic materials in which the rational introduction of different 'M's can yield correspondingly unique and interesting magnetic behaviors. Herein we present a generalized hydrothermal method for the synthesis of single-crystalline ferrite nanoparticles with 'M' = Mg, Fe, Co, Ni, Cu, and Zn, respectively, which can be systematically and efficaciously produced simply by changing the metal precursor. Our protocol can moreover lead to reproducible size control by judicious selection of various surfactants. Asmore » such, we have probed the effects of both (i) size and (ii) chemical composition upon the magnetic properties of these nanomaterials using complementary magnetometry and Mössbauer spectroscopy techniques. The structure of the samples was confirmed by atomic PDF analysis of X-ray and electron powder diffraction data as a function of particle size. These materials retain the bulk spinel structure to the smallest size (i.e., 3 nm). In addition, we have explored the catalytic potential of our ferrites as both (a) magnetically recoverable photocatalysts and (b) biological catalysts, and noted that many of our as-prepared ferrite systems evinced intrinsically higher activities as compared with their iron oxide analogues.« less

  17. Correlating size and composition-dependent effects with magnetic, Mössbauer, and pair distribution function measurements in a family of catalytically active ferrite nanoparticles

    SciTech Connect

    Wong, Stanislaus; Papaefthymiou, Georgia C.; Lewis, Crystal S.; Han, Jinkyu; Zhang, Cheng; Li, Qiang; Shi, Chenyang; Abeykoon, A. M.Milinda; Billinge, Simon J.L.; Stach, Eric; Thomas, Justin; Guerrero, Kevin; Munayco, Pablo; Munayco, Jimmy; Scorzelli, Rosa B.; Burnham, Philip; Viescas, Arthur J; Tiano, Amanda L.

    2015-05-06

    The magnetic spinel ferrites, MFe₂O₄ (wherein 'M' = a divalent metal ion such as but not limited to Mn, Co, Zn, and Ni), represent a unique class of magnetic materials in which the rational introduction of different 'M's can yield correspondingly unique and interesting magnetic behaviors. Herein we present a generalized hydrothermal method for the synthesis of single-crystalline ferrite nanoparticles with 'M' = Mg, Fe, Co, Ni, Cu, and Zn, respectively, which can be systematically and efficaciously produced simply by changing the metal precursor. Our protocol can moreover lead to reproducible size control by judicious selection of various surfactants. As such, we have probed the effects of both (i) size and (ii) chemical composition upon the magnetic properties of these nanomaterials using complementary magnetometry and Mössbauer spectroscopy techniques. The structure of the samples was confirmed by atomic PDF analysis of X-ray and electron powder diffraction data as a function of particle size. These materials retain the bulk spinel structure to the smallest size (i.e., 3 nm). In addition, we have explored the catalytic potential of our ferrites as both (a) magnetically recoverable photocatalysts and (b) biological catalysts, and noted that many of our as-prepared ferrite systems evinced intrinsically higher activities as compared with their iron oxide analogues.

  18. Synthesis and characterization of manganese ferrite nanoparticles by thermal treatment method

    NASA Astrophysics Data System (ADS)

    Goodarz Naseri, M.; Saion, E. Bin; Ahangar, H. Abbastabar; Hashim, M.; Shaari, A. H.

    2011-07-01

    Cubic structured manganese ferrite nanoparticles were synthesized by a thermal treatment method followed by calcination at various temperatures from 723 to 873 K. In this investigation, we used polyvinyl pyrrolidon (PVP) as a capping agent to control the agglomeration of the nanoparticles. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle sizes of manganese ferrite nanoparticles were determined by TEM, which increased with the calcination temperature from 12 to 22 nm and they had good agreement with XRD results. Fourier transform infrared spectroscopy confirmed the presence of metal oxide bands at all temperatures and the absence of organic bands at 873 K. Magnetic properties were demonstrated by a vibrating sample magnetometer, which showed a super-paramagnetic behavior for all samples and also saturation magnetization (Ms) increases from 3.06 to 15.78 emu/g by increasing the calcination temperature. The magnetic properties were also confirmed by the use of electron paramagnetic resonance spectroscopy, which revealed the existence of unpaired electrons and also measured peak-to-peak line width, resonant magnetic field and the g-factor.

  19. Method for preparing spherical ferrite beads and use thereof

    SciTech Connect

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.

    2002-01-01

    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.

  20. Metabolic Effects of Cobalt Ferrite Nanoparticles on Cervical Carcinoma Cells and Nontumorigenic Keratinocytes.

    PubMed

    Oliveira, Ana Beatriz Bortolozo; de Moraes, Fabio Rogério; Candido, Natalia Maria; Sampaio, Isabella; Paula, Alex Silva; de Vasconcellos, Adriano; Silva, Thais Cerqueira; Miller, Alex Henrique; Rahal, Paula; Nery, Jose Geraldo; Calmon, Marilia Freitas

    2016-12-02

    The cytotoxic response, cellular uptake, and metabolomic profile of HeLa and HaCaT cell lines treated with cobalt ferrite nanoparticles (CoFe2O4 NPs) were investigated in this study. Cell viability assays showed low cytotoxicity caused by the uptake of the nanoparticles at 2 mg/mL. However, metabolomics revealed that these nanoparticles impacted cell metabolism even when tested at a concentration that presented low cytotoxicity according to the cell viability assay. The two cell lines shared stress-related metabolic changes such as increase in alanine and creatine levels. A reduced level of fumarate was also observed in HeLa cells after treatment with the nanoparticles, and this alteration can inhibit tumorigenesis. Fumarate is considered to be an oncometabolite that can inhibit prolyl hydroxylase, and this inhibition stabilizes HIF1α, one of the master regulators of tumorigenesis that promotes tumor growth and development. In summary, this study showed that nanoparticle-treated HeLa cells demonstrated decreased concentrations of metabolites associated with cell proliferation and tumor growth. The results clearly indicated that treatment with these nanoparticles might cause a perturbation in cellular metabolism.

  1. [Superparamagnetic Cobalt Ferrite Nanoparticles "Blow up" Spatial Ordering of Double-stranded DNA Molecules].

    PubMed

    Yevdokimov, Yu M; Pershina, A G; Salyanov, V I; Magaeva, A A; Popenko, V I; Shtykova, E V; Dadinova, L A; Skuridin, S G

    2015-01-01

    The formation of cholesteric liquid-crystalline dispersions formed by double-stranded DNA molecules, handled by positively charged superparamagnetic cobalt ferrite nanoparticles, as well as action of these nanoparticles on DNA dispersion, are considered. The binding of magnetic nanoparticles to the linear double-stranded DNA in solution of high ionic strength (0.3 M NaCl) and subsequent phase exclusion of these complexes from polyethylene glycol-containing solutions lead to their inability to form dispersions, whose particles do possess the spatially twisted arrangement of neighboring double-stranded DNA molecules. The action of magnetic nanoparticles on DNA dispersion (one magnetic nanoparticle per one double-stranded DNA molecule) results in such "perturbation" of DNA structure at sites of magnetic nanoparticles binding that the regular spatial structure of DNA dispersion particles "blows up"; this process is accompanied by disappearance of both abnormal optical activity and characteristic Bragg maximum on the small-angle X-ray scattering curve. Allowing with the fact that the physicochemical properties of the DNA liquid-crystalline dispersion particles reflect features of spatial organization of these molecules in chromosomes of primitive organisms, it is possible, that the found effect can have the relevant biological consequences.

  2. HRTEM Study of the Role of Nanoparticles in ODS Ferritic Steel

    SciTech Connect

    Hsiung, L; Tumey, S; Fluss, M; Serruys, Y; Willaime, F

    2011-08-30

    Structures of nanoparticles and their role in dual-ion irradiated Fe-16Cr-4.5Al-0.3Ti-2W-0.37Y{sub 2}O{sub 3} (K3) ODS ferritic steel produced by mechanical alloying (MA) were studied using high-resolution transmission electron microscopy (HRTEM) techniques. The observation of Y{sub 4}Al{sub 2}O{sub 9} complex-oxide nanoparticles in the ODS steel imply that decomposition of Y{sub 2}O{sub 3} in association with internal oxidation of Al occurred during mechanical alloying. HRTEM observations of crystalline and partially crystalline nanoparticles larger than {approx}2 nm and amorphous cluster-domains smaller than {approx}2 nm provide an insight into the formation mechanism of nanoparticles/clusters in MA/ODS steels, which we believe involves solid-state amorphization and re-crystallization. The role of nanoparticles/clusters in suppressing radiation-induced swelling is revealed through TEM examinations of cavity distributions in (Fe + He) dual-ion irradiated K3-ODS steel. HRTEM observations of helium-filled cavities (helium bubbles) preferably trapped at nanoparticle/clusters in dual-ion irradiated K3-ODS are presented.

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

    SciTech Connect

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

    2009-11-02

    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.

  4. Structural, dielectric and magnetic properties of nickel substituted cobalt ferrite nanoparticles: Effect of nickel concentration

    SciTech Connect

    Velhal, Ninad B.; Patil, Narayan D.; Puri, Vijaya R.; Shelke, Abhijeet R.; Deshpande, Nishad G.

    2015-09-15

    Nickel substituted cobalt ferrite nanoparticles with composition Co{sub 1−x}Ni{sub x}Fe{sub 2}O{sub 4} (0.0 ≤ x ≤ 1.0) was synthesized using simple, low temperature auto combustion method. The X-ray diffraction patterns reveal the formation of cubic phase spinel structure. The crystallite size varies from 30-44 nm with the nickel content. Porous and agglomerated morphology of the bulk sample was displayed in the scanning electron microscopy. Micro Raman spectroscopy reveals continuous shift of E{sub g} and E{sub g}(2) stokes line up to 0.8 Ni substitution. The dispersion behavior of the dielectric constant with frequency and the semicircle nature of the impedance spectra show the cobalt nickel ferrite to have high resistance. The ferromagnetic nature is observed in all the samples, however, the maximum saturation magnetization was achieved by the 0.4 Ni substituted cobalt ferrite, which is up to the 92.87 emu/gm at 30K.

  5. Synthesis, Structural, Electrical and Magnetic Studies of Ni- Ferrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Godbole, Bhavana; Badera, Nitu; Shrivastava, S. B.; Jain, Deepti; Chandra, L. S. Sharath; Ganesan, V.

    Mono-dispersed NiFe2O4 nanoparticles have been synthesized using a stable ferric salt of FeCl3 with co-precipitation technique, for study of their structural, morphological and magnetic properties. The XRD pattern conforms the formation of FCC structure with the lattice constant 8.31Ao. The crystallite size was found to increase with the bath temperature ranging from 33 nm to 55 nm. The AFM results revealed that uniform disc shaped particles were obtained. The resistivity measurements show a metal like to semiconductor transition, which depends on the size of the grains. The magnetic study reveals that saturation magnetization increases with the grain thickness.

  6. Synthesis and characterization of zinc ferrite nanoparticles by a thermal treatment method

    NASA Astrophysics Data System (ADS)

    Naseri, Mahmoud Goodarz; Saion, Elias B.; Hashim, Mansor; Shaari, Abdul Halim; Ahangar, Hossein Abasstabar

    2011-07-01

    Crystalline zinc ferrite (ZnFe 2O 4) was prepared by the thermal treatment method, followed by calcination at various temperatures from 723 to 873 K. Poly (vinyl pyrrolidon) (PVP) was used as a capping agent to stabilize the particles and prevent them from agglomeration. The characterization studies were conducted by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle sizes of 17-31 nm were obtained by TEM images, which were in good agreement with the XRD results. Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of metal oxide bands at all temperatures and the absence of organic bands at 873 K. The magnetic properties were demonstrated by a vibrating sample magnetometer (VSM), which displayed super paramagnetic behaviors for the calcined samples. The present study also substantiated that, in ferrites, the values of the quantities that were acquired by VSM, such as the saturation magnetization and coercivity field, are primarily dependent on the methods of preparation of the ferrites. Electron paramagnetic resonance (EPR) spectroscopy showed the existence of unpaired electrons and measured the peak-to-peak line width ( ΔH), the resonant magnetic field ( Hr), and the g-factor values.

  7. Structural, electrical and magnetic properties of Sc3+ doped Mn-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Angadi, V. Jagdeesha; Choudhury, Leema; Sadhana, K.; Liu, Hsiang-Lin; Sandhya, R.; Matteppanavar, Shidaling; Rudraswamy, B.; Pattar, Vinayak; Anavekar, R. V.; Praveena, K.

    2017-02-01

    Sc3+ doped Mn0.5Zn0.5ScyFe2-yO4 (y=0.00, 0.01, 0.03 and 0.05) nanoparticles were synthesized by solution combustion method using mixture of fuels were reported for the first time. The mixture of fuels plays an important role in obtaining nano crystalline, single phase present without any heat treatment. X-ray diffraction (XRD) results confirm the formation of the single-phase ferrites which crystallize in cubic spinel structure. The Fourier transform infrared spectra (FTIR) exhibit two prominent bands around 360 cm-1 and 540 cm-1 which are characteristic feature of spinel ferrite. The transmission electron microscope (TEM) micrographs revealed the nanoparticles to be nearly spherical in shape and of fairly uniform size. The room temperature impedance spectra (IS) and vibrating sample magnetometry (VSM) measurements were carried out in order to study the effect of doping (Sc3+) on the characteristic properties of Mn-Zn ferrites. Further, the frequency dependent dielectric constant and dielectric loss were found to decrease with increasing multiple Sc3+ concentration. Nyquist plot in the complex impedance spectra suggest the existence of multiple electrical responses. Magnetic measurements reveals that saturation magnetization (Ms), remnant magnetization (Mr), magnetic moment (ηB) and magnetic particle size (Dm) increase with Sc3+ ion concentration up to x=0.03 and then decrease. The values of spin canting angle (αY-K) and the magnetic particle size (Dm) are found to be in the range of 68-75° and 10-19 nm respectively with Sc3+ concentration. The room temperature Mössbauer spectra were fitted with two sextets corresponding to ions at tetrahedral (A-) and octahedral (B-) sites confirms the spinel lattice. The ferromagnetic resonance (FMR) spectra's has shown that high concentration of scandium doping leads to an increase in dipolar interaction and decrease in super exchange interaction.

  8. Effect of surface structure on the dynamic magnetic response in Ni-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Poddar, P.; Swaminathan, R.

    2005-03-01

    Surface magnetic spin structure plays a dominant role in determining the effective anisotropy in magnetic nanostructures. To probe the anisotropy in nanoparticle systems, we have developed an RF transverse susceptibility technique based on a resonant tunnel-diode oscillator (TDO). Transverse susceptibility measurements were performed on NiZn ferrite nanoparticles (synthesized using a RF induction plasma torch) over a wide temperature range (10K to 300K) and magnetic fields (-10kOe to 10kOe). As-synthesized polydisperse nanoparticles showed broad peaks at the characteristic anisotropy fields that are attributed to the presence of both the (100) and (111) surfaces and their respective surface anisotropy contributions. The peak positions and heights were found to be sensitive to the particle size dispersion and surface magnetic spin structure. The polydisperse particles were coated with oleic acid and size-selected using ultra-centrifugation. The anisotropy peaks are conspicuously absent in the size-selected smaller nanoparticles. This is understood within the framework of a surface structure model based on isotropic canted triangular spin structures on the dominant (111) surfaces in the smallest nanoparticles. Work at USF supported by NSF through Grant No. CTS-0408933. RS and MEM thank the Institute of Complex Engineering Systems (ICES), CMU for support.

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

    SciTech Connect

    Mahmoodi, Niyaz Mohammad; Bashiri, Marziyeh; Moeen, Shirin Jebeli

    2012-12-15

    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.

  10. Ultrafast and continuous synthesis of crystalline ferrite nanoparticles in supercritical ethanol.

    PubMed

    Pascu, Oana; Marre, Samuel; Aymonier, Cyril; Roig, Anna

    2013-03-07

    Magnetic nanoparticles (NPs) are of increasing interest in various industrially relevant products. For these, the development of greener and faster approaches facilitating scaling-up production is of paramount importance. Here, we report a novel, green and potentially scalable approach for the continuous and ultrafast (90 s) synthesis of superparamagnetic ferrite NPs (MnFe(2)O(4), Fe(3)O(4)) in supercritical ethanol (scEtOH) at a fairly moderate temperature (260 °C). ScEtOH exhibits numerous advantages such as its production from bio-resources, its lack of toxicity and its relatively low supercritical coordinates (p(c) = 6.39 MPa and T(c) = 243 °C), being therefore appropriate for the development of sustainable technologies. The present study is completed by the investigation of both in situ and ex situ NP surface functionalization. The as-obtained nanoparticles present good crystallinity, sizes below 8 nm, superparamagnetic behavior at room temperature and high saturation magnetization. Moreover, depending on the capping strategy, the ferrite NPs present extended (for in situ coated NPs) or short-term (for ex situ coated NPs) colloidal stability.

  11. Surface spin-glass in cobalt ferrite nanoparticles dispersed in silica matrix

    NASA Astrophysics Data System (ADS)

    Zeb, F.; Sarwer, W.; Nadeem, K.; Kamran, M.; Mumtaz, M.; Krenn, H.; Letofsky-Papst, I.

    2016-06-01

    Surface effects in cobalt ferrite (CoFe2O4) nanoparticles dispersed in a silica (SiO2) matrix were studied by using AC and DC magnetization. Nanoparticles with different concentration of SiO2 were synthesized by using sol-gel method. Average crystallite size lies in the range 25-34 nm for different SiO2 concentration. TEM image showed that particles are spherical and elongated in shape. Nanoparticles with higher concentration of SiO2 exhibit two peaks in the out-of-phase ac-susceptibility. First peak lies in the high temperature regime and corresponds to average blocking temperature of the nanoparticles. Second peak lies in the low temperature regime and is attributed to surface spin-glass freezing in these nanoparticles. Low temperature peak showed SiO2 concentration dependence and was vanished for large uncoated nanoparticles. The frequency dependence of the AC-susceptibility of low temperature peak was fitted with dynamic scaling law which ensures the presence of spin-glass behavior. With increasing applied DC field, the low temperature peak showed less shift as compared to blocking peak, broaden, and decreased in magnitude which also signifies its identity as spin-glass peak for smaller nanoparticles. M-H loops showed the presence of more surface disorder in nanoparticles dispersed in 60% SiO2 matrix. All these measurements revealed that surface effects become strengthen with increasing SiO2 matrix concentration and surface spins freeze in to spin-glass state at low temperatures.

  12. An integrated study of thermal treatment effects on the microstructure and magnetic properties of Zn-ferrite nanoparticles

    SciTech Connect

    Antic, Bratislav; Perovic, Marija; Kremenovic, Aleksandar; Blanusa, Jovan; Spasojevic, Vojislav; Vulic, Predrag; Bessais, Lotfi; Bozin, Emil S

    2015-09-30

    The evolution of the magnetic state, crystal structure and microstructure parameters of nanocrystalline zinc–ferrite, tuned by thermal annealing of ~4 nm nanoparticles, was systematically studied by complementary characterization methods. Structural analysis of neutron and synchrotron x-ray radiation data revealed a mixed cation distribution in the nanoparticle samples, with the degree of inversion systematically decreasing from 0.25 in an as-prepared nanocrystalline sample to a non-inverted spinel structure with a normal cation distribution in the bulk counterpart. The results of DC magnetization and Mossbauer spectroscopy experiments indicated a superparamagnetic relaxation in ~4 nm nanoparticles, albeit with different freezing temperatures Tf of 27.5 K and 46 K, respectively. The quadrupole splitting parameter decreases with the annealing temperature due to cation redistribution between the tetrahedral and octahedral sites of the spinel structure and the associated defects. DC magnetization measurements indicated the existence of significant interparticle interactions among nanoparticles (‘superspins’). Additional confirmation for the presence of interparticle interactions was found from the fit of the Tf(H) dependence to the AT line, from which a value of the anisotropy constant of Keff = 5.6 × 105 erg cm-3 was deduced. Further evidence for strong interparticle interactions was found from AC susceptibility measurements, where the frequency dependence of the freezing temperature Tf(ƒ) was satisfactory described by both Vogel–Fulcher and dynamic scaling theory, both applicable for interacting systems. The parameters obtained from these fits suggest collective freezing of magnetic moments at Tf .

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

    PubMed Central

    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

    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

  14. Pr 3+-substituted W-type barium ferrite: Preparation and electromagnetic properties

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    The W-type ferrites doped with Pr3+, BaCoNiPrxFe16-xO27 (x=0-0.20), were prepared by a sol-gel method. The structure and electromagnetic properties of the samples are studied using powder X-ray diffraction, field emission scanning electron microscope, vibrating sample magnetometer and vector network analyzer. All the samples are hexagonal platelet-like W-type barium ferrite. These synthesized samples exhibit paramagnetism and strong magnetism. The saturation magnetization (Ms) increases with the increase of Pr3+ content. The real part of complex permittivity (ε‧) decreases and the imaginary part (ε″) increases with Fe3+ replaced by Pr3+. The imaginary part of complex permittivity (μ″) increases and the real part (μ‧) decreases after Pr3+ is doped. Furthermore, the doped Pr3+ improves the microwave absorbency.

  15. Structural and magnetic properties of Mg-Zn ferrites (Mg1-xZnxFe2O4) prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Reyes-Rodríguez, Pamela Yajaira; Cortés-Hernández, Dora Alicia; Escobedo-Bocardo, José Concepción; Almanza-Robles, José Manuel; Sánchez-Fuentes, Héctor Javier; Jasso-Terán, Argentina; De León-Prado, Laura Elena; Méndez-Nonell, Juan; Hurtado-López, Gilberto Francisco

    2017-04-01

    In this study, the Mg1-xZnxFe2O4 nanoparticles (x=0-0.9) were prepared by sol-gel method. These ferrites exhibit an inverse spinel structure and the lattice parameter increases as the substitution of Zn2+ ions is increased. At lower Zn content (0.1≤x≤0.5), saturation magnetization (Ms) increases, while it decreases at higher Zn content (x≥6). The remnant magnetization (0.17-2.0 emu/g) and coercive field (6.0-60 Oe) indicate a ferrimagnetic behavior. The average core diameter of selected ferrites is around 15 nm and the nanoparticles morphology is quasi spherical. The heating ability of some Mg0.9Zn0.1Fe2O4 and Mg0.7Zn0.3Fe2O4 aqueous suspensions indicates that the magnetic nanoparticles can increase the medium temperature up to 42 °C in a time less than 10 min

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

    PubMed

    Zaki, H M; Al-Heniti, S

    2012-09-01

    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.

  17. In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

    DOE PAGES

    Ferrari, S.; Kumar, R. S.; Grinblat, F.; ...

    2016-04-23

    We have studied the high-pressure structural behavior of zinc ferrite (ZnFe2O4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe2O4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn2O4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa. For comparison, we also studied themore » compression behavior of magnetite (Fe3O4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe2O4 and Fe3O4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.« less

  18. Hydrothermal synthesis of mixed zinc-cobalt ferrite nanoparticles: structural and magnetic properties

    NASA Astrophysics Data System (ADS)

    Coppola, P.; da Silva, F. G.; Gomide, G.; Paula, F. L. O.; Campos, A. F. C.; Perzynski, R.; Kern, C.; Depeyrot, J.; Aquino, R.

    2016-05-01

    We synthesize Zn-substituted cobalt ferrite (Zn x Co1- x Fe2O4, with 0 ≤ x ≤ 1) magnetic nanoparticles by a hydrothermal co-precipitation method in alkaline medium. The chemical composition is evaluated by atomic absorption spectroscopy and energy-dispersive X-ray spectroscopy techniques. The structure and morphology of the nanopaticles are investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. XRD Rietveld refinements reveal the cation distribution among the tetrahedral (A) and octahedral (B) sites. It shows that up to x 0.5 zinc ions occupy preferably A-sites, above which Zn ions begin also a gradual occupancy of B-sites. TEM images show nanoparticles with different shapes varying from spheres, cubes, to octahedrons. Hysteresis loop properties are studied at 300 and 5 K. These properties are strongly influenced by the Zn and Co proportion in the nanoparticle composition. At 300 K, only samples with high Co content present hysteresis. At 5 K, the reduced remanent magnetization ratio ( M R/ M S) and the coercivity ( H C) suggest that nanoparticles with x < 0.5 have cubic anisotropy. A kink on the hysteresis loop, close to the remanence, is observed at low temperature. This feature is presumably associated to interplay between hard and soft anisotropy regimes in the powder samples.

  19. In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

    SciTech Connect

    Ferrari, S.; Kumar, R. S.; Grinblat, F.; Aphesteguy, J. C.; Saccone, F. D.; Errandonea, D.

    2016-04-23

    We have studied the high-pressure structural behavior of zinc ferrite (ZnFe2O4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe2O4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn2O4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa. For comparison, we also studied the compression behavior of magnetite (Fe3O4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe2O4 and Fe3O4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.

  20. Magnetite Nanoparticles Prepared By Spark Erosion

    NASA Astrophysics Data System (ADS)

    Maiorov, M.; Blums, E.; Kronkalns, G.; Krumina, A.; Lubane, M.

    2016-08-01

    In the present research, we study a possibility of using the electric spark erosion method as an alternative to the method of chemical co-precipitation for preparation of magnetic nanoparticles. Initiation of high frequency electric discharge between coarse iron particles under a layer of distilled water allows obtaining pure magnetite nanoparticles.

  1. Preparation of DPPE-Stabilized Gold Nanoparticles

    ERIC Educational Resources Information Center

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

    2005-01-01

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

  2. Synthesis of cobalt ferrite nanoparticles from thermolysis of prospective metal-nitrosonaphthol complexes and their photochemical application in removing methylene blue

    NASA Astrophysics Data System (ADS)

    Tavana, Jalal; Edrisi, Mohammad

    2016-03-01

    In this study, cobalt ferrite (CoFe2O4) nanoparticles were synthesized by two novel methods. The first method is based on the thermolysis of metal-NN complexes. In the second method, a template free sonochemical treatment of mixed cobalt and iron chelates of α-nitroso-β-naphthol (NN) was applied. Products prepared through method 1 were spherical, with high specific surface area (54.39 m2 g-1) and small average crystalline size of 13 nm. However, CoFe2O4 nanoparticles prepared by method 2 were in random shapes, a broad range of crystalline sizes and a low specific surface area of 25.46 m2 g-1 though highly pure. A Taguchi experimental design was implemented in method 1 to determine and obtain the optimum catalyst. The structural and morphological properties of products were investigated by x-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, Brunauer-Emmett-Teller and dynamic laser light scattering. The crystalline size calculations were performed using Williamson-Hall method on XRD spectrum. The photocatalytic activity of the optimum nanocrystalline cobalt ferrite was investigated for degradation of a representative pollutant, methylene blue (MB), and visible light as energy source. The results showed that some 92% degradation of MB could be achieved for 7 h of visible light irradiation.

  3. Nanocrystalline magnesium ferrite prepared for photocatalytic applications by using the polymerized complex method

    NASA Astrophysics Data System (ADS)

    Dom, Rekha; Borse, Pramod H.; Hong, Kyong-Soo; Choi, Seyong; Lee, Byeong Seob; Ha, Myoung Gyu; Kim, Jong Pil; Jeong, Euh Duck; Kim, Hyun Gyu

    2015-11-01

    Magnesium ferrite (MgFe2O4) exhibiting a spinel phase was synthesized by using the polymerized complex and the solid-state reaction methods, and its physico-chemical properties were studied to explore the water-splitting under visible light photons. The study revealed the potential for using MgFe2O4 particles for photo-catalytic application. The structural study provided information on ferrite nano-crystallites fabricated by using the polymer complex method. The morphological studies demonstrated that, in contrast to the solid-state reaction method, a homogenous, monodispersed ferrite photocatalyst could be formed by using the polymerized complex method. The optical study revealed a larger visible-light absorption capability for the nanosized MgFe2O4 photocatalysts prepared by using the polymer complex methods, and indicated a red-shift of the bandgap by 0.06 eV as compared to the bandgap of the bulk. These nanocrystallites were highly photoactive with respect to the photodegradation and photocatalytic hydrogen evolution applications. The electrochemical analysis showed that they exhibited favorable bandedge positions suitable for photocatalytic H2 evolution. Thus, nanocrystalline MgFe2O4 is an active visible-light photocatalyst, that might be useful for the decomposition of water.

  4. Highly resistive Mn-Zn ferrite films prepared from aqueous solution for GHz conducted noise suppressors

    NASA Astrophysics Data System (ADS)

    Matsushita, Nobuhiro; Abe, Tatsunobu; Kondo, Koichi; Yoshida, Shigeyoshi; Abe, Masanori

    2005-05-01

    We have prepared Mn-Zn ferrite films (MnxZnyFezO4.00-δ: 0.23108Ω/sq was attained for the film having z<2.6. The deposited Mn-Zn ferrite films had a large saturation magnetization Ms=380-460emu/cm3 and relatively low coercivity Hc=11-29Oe. The Mn-Zn ferrite films contacted to a microstrip line (50Ω) exhibited very large transmission loss ΔPloss per thickness t, ΔPloss/t, of about 10 times larger than that of commercialized composite sheet. They exhibited sufficiently low reflection coefficient S11<-10dB. These films were applicable as noise current suppressors deposited on an interlayer of multilayer printed circuit boards.

  5. Nanotoxicological study of polyol-made cobalt-zinc ferrite nanoparticles in rabbit.

    PubMed

    Hanini, Amel; Massoudi, Mohamed El; Gavard, Julie; Kacem, Kamel; Ammar, Souad; Souilem, Ouajdi

    2016-07-01

    The increasing use of engineered nanomaterials in commercial manufacturing and consumer products presents an important toxicological concern. Superparamagnetic zinc-cobalt ferrite nanoparticles (SFN) emerge as a promising tool for early cancer diagnostics and targeted therapy. However, toxicity and biological activities of SFN should be evaluated in vitro and in vivo in animal before any clinical application. In this study we aim to synthesize and characterize such objects using polyol process in order to assess its nanotoxicological profile in vitro as well as in vivo. The produced particles consist of a cobalt-zinc ferrite phase corresponding to the Zn0.8Co0.2Fe2O4 composition. They are isotropic in shape single crystals of 8nm in size. The thermal variation of their dc-magnetization confirms their superparamagnetic behavior. In vitro, acute exposure (4h) to them (100μgmL(-1)) induced an important decrease of healthy Human Umbilical Vein Endothelial Cells (HUVECs) viability. In vivo investigation in New-Zealand rabbits revealed that they lead to tissue toxicities; in lungs, liver and kidneys. Our investigations report, for the first time as far as we know, that SFN exhibit harmful properties in human cells and mammals.

  6. Structural and magnetic properties of calcium doped nickel ferrite nanoparticles by co-precipitation method

    NASA Astrophysics Data System (ADS)

    Vigneswari, T.; Raji, P.

    2017-01-01

    It is a truism that a sequence of calcium doped nickel ferrite (with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanoparticles are combined by co-precipitation technique. X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) scrutinize the formation of single-phase inverse spinel structure in all the compositions. The lattice framework increases with the increase in calcium concentration and it exhibits the development of unit cell. Crystallite size in the range of 22-34 nm is viewed and also augmented the level of calcium. The elemental composition of pure and calcium doped nickel ferrite has been procured from Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Energy Dispersive X-ray analysis (EDX). It is interesting to note that the substitution of calcium increasingly exerts influence on the magnetic characteristics. These observations paved the way for the room temperature of magnetization measurements. The saturation magnetization and the experimental value of magnetic moment are noticed to enlarge initially up to x = 0.2, and then decrease incessantly with increase in the Ca content x. The increase and the decrease of saturation magnetization have widely been expounded by Neel's collinear two-sublattice model and Yafet-Kittel (Y-K) three-sub lattice model.

  7. Magnetic Nanoparticles: Synthesis, Characterization and Magnetic Properties of Cobalt Aluminum Ferrite.

    PubMed

    Zaki, H M; Al-Heniti, Saleh H; Al-Hadeethi, Y; Alsanoosi, A M

    2016-05-01

    Nanoparticles of the ferrite system CoFe(2-x)Al(x)O4 (x = 0.0, 0.3, 0.7 and 1.0) were synthesized through the co-precipitation technique. Thermal decomposition process and formation of a single crystalline phase were followed using thermal differential analysis technique (DTA). X-ray powder diffraction patterns of the samples confirmed the formation of a nano-size single spinel phase. The average crystallite size was found to be in the range 20-63 nm for all samples. This was further confirmed by TEM of one of the samples, with concentration x = 1.0 which was found statistically to be 27 nm. This agrees well with the value of 24 nm deduced by means of X-ray diffraction method for the same sample. A considerable decrease in the intensity of the octahedral bands is observed as the aluminum concentration increases, and even vanishes completely at x = 1.0 indicating the migration of cations between the octahedral and tetrahedral sites. The magnetic hysteresis loops at room temperature showed decrease in both, coercivity and saturation magnetization as the non-magnetic Al3+ ions content increases. The relative values of M(r0/M(s) were found to be between 0.44 and 0.31 for the samples with a remarkable change in the squareness of the loops. This is highly beneficial for the microwave and memory devices applications of these nano sized ferrite system.

  8. Effect of In3+ substitution on structural and magnetic properties of Ni ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Meng, Fanbin; Shang, Xueni; Zhang, Wei; Zhang, Yujie

    2017-01-01

    NiInxFe2-xO4 (x=0.0, 0.1, 0.2, 0.3, 0.4) ferrite nanoparticles have been synthesized by sol-gel autocombustion technique. The effect of In3+ substitution on the structural and magnetic properties of nickel ferrite has been analyzed by X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), Field emission scanning electron microscopy (FESEM) and Vibrating sample magnetometer (VSM). The XRD results confirmed the formation of single cubic spinel phase for 0 ≤ x ≤ 0.3 and the appearance of secondary phase of In2O3 for x=0.4. The lattice parameter increases (from 8.3152 to 8.4336 Å) with indium content. The FTIR results illustrated that the absorption intensity of peak at about 594 cm-1 increases with increasing the In3+ ions. The saturation magnetization increases and then decreases while the coercivity decreases along with In3+substitution. The maximal saturation magnetization emerged at the composition of NiIn0.2Fe1.8O4 (42.111 emu/g).

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

    PubMed

    Soltani, T; Entezari, M H

    2013-09-01

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

  10. Functionalized bismuth ferrite harmonic nanoparticles for cancer cells labeling and imaging

    NASA Astrophysics Data System (ADS)

    Passemard, Solène; Staedler, Davide; Sonego, Giona; Magouroux, Thibaud; Schneiter, Guillaume Stéphane; Juillerat-Jeanneret, Lucienne; Bonacina, Luigi; Gerber-Lemaire, Sandrine

    2015-10-01

    Bismuth ferrite (BFO) harmonic nanoparticles (NPs) display high nonlinear optical efficiency and excellent biocompatibility profile which make them attractive for the development of diagnostic applications as contrast agents. In this study, we present a general method for the functionalization of this material with chemical ligands targeting cancer molecular biomarkers. In particular, a conjugation protocol based on click reaction between alkynyl-containing targeting ligands and poly(ethylene glycol)-coated BFO NPs (67.7 nm) displaying surface reactive azido groups was developed. Copper-free click reaction allowed fast and efficient conjugation of a covalent inhibitor of prolyl-specific endopeptidases to coated BFO NPs. The ability of these functionalized nanomaterials (134.2 nm) to act as imaging probes for cancer cells was demonstrated by the selective labeling of human lung cancer cells.

  11. Improvement of drug delivery by hyperthermia treatment using magnetic cubic cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Dey, Chaitali; Baishya, Kaushik; Ghosh, Arup; Goswami, Madhuri Mandal; Ghosh, Ajay; Mandal, Kalyan

    2017-04-01

    In this study, we report a novel synthesis method, characterization and application of a new class of ferromagnetic cubic cobalt ferrite magnetic nanoparticles (MNPs) for hyperthermia therapy and temperature triggered drug release. The MNPs are characterized by XRD, TEM, FESEM, AC magnetic hysteresis and VSM. These MNPs were coated with folic acid and loaded with an anticancer drug. The drug release studies were done at two different temperatures (37 °C and 44 °C) with progress of time. It was found that higher release of drug took place at elevated temperature (44 °C). We have developed a temperature sensitive drug delivery system which releases the heat sensitive drug selectively as the particles are heated up under AC magnetic field and controlled release is possible by changing the external AC magnetic field.

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

    NASA Astrophysics Data System (ADS)

    Kumar, E. Ranjith; Kamzin, Aleksandr S.; Prakash, T.

    2015-03-01

    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.

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

    SciTech Connect

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

    2005-05-15

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

  14. Recent advances in nanosized Mn-Zn ferrite magnetic fluid hyperthermia for cancer treatment.

    PubMed

    Lin, Mei; Huang, Junxing; Sha, Min

    2014-01-01

    This paper reviews the recent research and development of nanosized manganese zinc (Mn-Zn) ferrite magnetic fluid hyperthermia (MFH) for cancer treatment. Mn-Zn ferrite MFH, which has a targeted positioning function that only the temperature of tumor tissue with magnetic nanoparticles can rise, while normal tissue without magnetic nanoparticles is not subject to thermal damage, is a promising therapy for cancer. We introduce briefly the composition and properties of magnetic fluid, the concept of MFH, and features of Mn-Zn ferrite magnetic nanoparticles for MFH such as thermal bystander effect, universality, high specific absorption rate, the targeting effect of small size, uniformity of hyperthermia temperature, and automatic temperature control and constant temperature effect. Next, preparation methods of Mn-Zn ferrite magnetic fluid are discussed, and biocompatibility and biosecurity of Mn-Zn ferrite magnetic fluid are analyzed. Then the applications of nanosized Mn-Zn ferrite MFH in cancer are highlighted, including nanosized Mn-Zn ferrite MFH alone, nanosized Mn-Zn ferrite MFH combined with As2O3 chemotherapy, and nanosized Mn-Zn ferrite MFH combined with radiotherapy. Finally, the combination application of nanosized Mn-Zn ferrite MFH and gene-therapy is conceived, and the challenges and perspectives for the future of nanosized Mn-Zn ferrite MFH for oncotherapy are discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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/γ-Al2O3, Ni-Fe/γ-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.

  16. Microwave anneal effect on magnetic properties of Ni 0.6Zn 0.4Fe 2O 4 nano-particles prepared by conventional hydrothermal method

    NASA Astrophysics Data System (ADS)

    Wang, Zhongzhu; Xie, Yanyu; Wang, Peihong; Ma, Yongqing; Jin, Shaowei; Liu, Xiansong

    2011-12-01

    Ni0.6Zn0.4Fe2O4 ferrite nano-particles with a crystallite size of about 20 nm were prepared by the conventional hydrothermal method, followed by annealing in a microwave oven for 7.5-15 min. The microstructure and magnetic properties of the samples were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The microwave annealing process has slight effect on the morphology and size of Ni0.6Zn0.4Fe2O4 ferrite nano-particles. However it reduces the lattice parameter and enhances the densification of the particles, and then greatly increases the saturation magnetization (50-56 emu/g) and coercive force of the samples as compared to the non-annealing condition. The microwave annealing process is an effective way to rapidly synthesize high performance ferrite nano-particle.

  17. Method to prepare nanoparticles on porous mediums

    DOEpatents

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

    2010-08-10

    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.

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

    SciTech Connect

    Ghasemi, Ali; Paesano, Andrea; Cerqueira Machado, Carla Fabiana; Shirsath, Sagar E.; Liu, Xiaoxi; Morisako, Akimitsu

    2014-05-07

    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.

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

    SciTech Connect

    Lazarević, Zorica Ž.; Jovalekić, Čedomir; Sekulić, Dalibor L.; Milutinović, Aleksandra; Baloš, Sebastian; Slankamenac, Miloš; Romčević, Nebojša Ž.

    2013-10-15

    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 ΔE 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 α-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 (ε) and dielectric loss tangent (tan δ) of NiFe{sub 2}O{sub 4} samples obtained by the same methods but starting from different initial components was observed.

  20. Extraordinary high dielectric constant, electrical and magnetic properties of ferrite nanoparticles at room temperature

    NASA Astrophysics Data System (ADS)

    Batoo, Khalid Mujasam; Mir, Feroz Ahmed; Abd El-sadek, M.-S.; Shahabuddin, Md.; Ahmed, Niyaz

    2013-11-01

    Nanoparticles of spinel ferrites of basic composition Ni1- x Co x Fe2O4 (0.0 ≤ x ≤ 0.05) were synthesized through modified co-precipitation method, and were characterized for structural, transport electrical and magnetic properties using XRD, HRTEM, FTIR, LCR meter and VSM techniques, respectively. XRD analysis showed that all the samples are single-phase cubic spinel in structure. The average crystallite sizes of the nanoparticles were found between 30 nm to 45 nm. Real and imaginary parts of the impedance ( Z' and Z″) suggested coexistence of two relaxation regimes: one was introduced by electrode polarization, while the other was attributed to the coeffect of grain and grain boundary effects. The dielectric constant of the samples was found very high, which showed non-Debye relaxation phenomena, while conductivity of the samples exhibited a two-segment behavior with frequency. The room temperature M-H curves suggested that the samples exhibit supermagnetism, and the saturation magnetization increases with increasing Co2+ ion substitution.

  1. Superior electro-optic response in multiferroic bismuth ferrite nanoparticle doped nematic liquid crystal device

    PubMed Central

    Nayek, Prasenjit; Li, Guoqiang

    2015-01-01

    A superior electro-optic (E-O) response has been achieved when multiferroic bismuth ferrite (BiFeO3/BFO) nanoparticles (NPs) were doped in nematic liquid crystal (NLC) host E7 and the LC device was addressed in the large signal regime by an amplitude modulated square wave signal at the frequency of 100 Hz. The optimized concentration of BFO is 0.15 wt%, and the corresponding total optical response time (rise time + decay time) for a 5 μm-thick cell is 2.5 ms for ~7 Vrms. This might be exploited for the construction of adaptive lenses, modulators, displays, and other E-O devices. The possible reason behind the fast response time could be the visco-elastic constant and restoring force imparted by the locally ordered LCs induced by the multiferroic nanoparticles (MNPs). Polarized optical microscopic textural observation shows that the macroscopic dislocation-free excellent contrast have significant impact on improving the image quality and performance of the devices. PMID:26041701

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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.

  3. In Vitro Toxicological Assessment of Cobalt Ferrite Nanoparticles in Several Mammalian Cell Types.

    PubMed

    Abudayyak, Mahmoud; Altincekic Gurkaynak, Tuba; Özhan, Gül

    2017-02-01

    Nanoparticles have been widely used in various fields due to the superior physicochemical properties and functions. As a result, human exposure to nanoparticles increases dramatically. Previous researches have shown that nanoparticles could travel through the respiratory, digestive system, or skin into the blood and then to the secondary organs such as the brain, heart, and liver. Besides, the nanoparticle toxicity is controversial and dependent on the sensitivity of the cell type, route of exposure, and condition, as well as their characteristics. Similarly, cobalt ferrite nanoparticles (CoFe2O4-NPs) have been used in different industrial fields, and have also various application possibilities in medical and biomedical fields. CoFe2O4-NPs induce toxic responses in various organisms such as human, mice, and algae. However, there is a serious deficit of information concerning their effects on human health and the environment. We aimed to investigate the toxic effects of CoFe2O4-NPs on liver (HepG2), colon (Caco-2), lung (A549), and neuron (SH-SY5Y) cells, which reflect different exposure routes in vitro, by using various toxicological endpoints. The cytotoxicity, genotoxicity, oxidative damage, and apoptosis induction of CoFe2O4-NPs (39 ± 17 nm) were evaluated. After 24 h, the nanoparticles decreased cell viability at ≤100 μg/mL, while increasing viability at >100 μg/mL. CoFe2O4-NPs induced DNA and oxidative damage with increased malondialdehyde (MDA) and 8-hydroxy deoxyguanosine (8-OHdG) levels and decreased glutathione (GSH) levels with no change in protein carbonyl (PC) levels. CoFe2O4-NPs had apoptotic effect in HepG2 and Caco-2 cells in a concentration-dependent manner and necrotic effects on SH-SY5Y and A549 cells. Consequently, the adverse effects of CoFe2O4-NPs should raise concern about their safety in consumer products.

  4. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    NASA Astrophysics Data System (ADS)

    Chen, Daming; Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12-xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12-xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement.

  5. Factors controlling phase formation of novel Sr-based Y-type hexagonal ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Tholkappiyan, R.; Vishista, K.; Hamed, Fathalla

    2017-02-01

    New Sr-based Y-type nanocrystalline hexagonal ferrites with a nominal chemical composition of Sr 2Mg 2Fe 12 O 22 (Sr 2Y) were prepared by autocombustion from mixtures of Sr(NO 3) 2, Mg(NO 3) 2ṡ6H 2O and Fe(NO 3) 3ṡ9H 2O. The newly prepared Sr 2Y nanocrystalline particles were characterized by powder X-ray diffraction (XRD). A well crystalline phase of Sr 2Y with hexagonal crystal structure was observed. Fourier transform infrared spectroscopy (FTIR) studies revealed the information about the positions of the ions and their bonds within the lattice structure of the Sr 2Y. The chemical elements and their oxidation states in the Sr 2Y hexaferrites were determined using X-ray photoelectron spectroscopy (XPS). The XRD, FTIR and XPS studies confirmed the formation of Sr 2Mg 2Fe 12 O 22 hexaferrites. The morphology and porosity of the prepared Sr 2Y nanocrystalline Sr 2Y hexaferrite particles were studied by field emission scanning electron microscopy. The magnetic properties of Sr 2Y hexaferrites showed dependence on the methods of preparation conditions and calcination treatments. The values of coercivity, saturation magnetization and retentivity were in the range of 21.33-19.66 kA m -1, 42.44- 38.72 emu g -1 and 10.05-13.19 emu g -1 respectively.

  6. Magnetic properties of cobalt ferrite synthesized by hydrothermal method

    NASA Astrophysics Data System (ADS)

    Allaedini, Ghazaleh; Tasirin, Siti Masrinda; Aminayi, Payam

    2015-05-01

    In this study, the magnetic properties of nanocrystalline cobalt ferrite synthesized via the hydrothermal method have been investigated. The structural properties of the produced powders were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The observed XRD pattern confirmed the spinel/cubic structure of the prepared cobalt ferrite. The SEM pictures show that the simple hydrothermal method produces uniform sphere-shaped nanopowders. Moreover, infrared spectroscopy was used to confirm the formation of cobalt ferrite particles. Magnetic hysteresis was measured using a vibrating sample magnetometer in a maximum field of 10 kOe. The magnetization of the prepared nanoparticles was investigated, and the saturation magnetization ( M s), remanence ( M r), and coercivity ( H c) were derived from the hysteresis loops. The results revealed that the cobalt ferrite nanoparticles synthesized via the simple hydrothermal method exhibit superior magnetic properties.

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

    PubMed

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

    2015-03-21

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

  8. Inter-atomic bonding and dielectric polarization in Gd3+ incorporated Co-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Pawar, R. A.; Desai, S. S.; Patange, S. M.; Jadhav, S. S.; Jadhav, K. M.

    2017-04-01

    A series of ferrite with a chemical composition Co0.7Zn0.3GdxFe2-xO4 (where x=0.0 to x=0.1) were prepared by sol-gel auto-combustion method. X-ray diffraction pattern were used to determine the crystal structure and phase formation of the prepared samples. Scanning electron microscopy is used to study the surface morphology of the prepared samples. Elastic properties were determined from the infrared spectroscopy. Debye temperature, wave velocities, elastic constants found to increase with the increase in Gd3+ substitution. Dielectric properties such as dielectric constant and dielectric loss were studied as a function of Gd3+ substitution and frequency. Dielectric constant decreased with the increase in frequency and Gd3+ substitution. Behavior of dielectric properties was explained on the basis of Maxwell-Wagner interfacial polarization which in accordance with Koops phenomenological theory. Real and imaginary part of impedance was studied as a function of resistance and Gd3+ substitution. The behavior of impedance is systematically discussed on the basis of resistance-capacitance circuit.

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

    PubMed

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

    2012-08-01

    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.

  10. Enhanced Terahertz Radiation Generation of Photoconductive Antennas Based on Manganese Ferrite Nanoparticles.

    PubMed

    Lai, Weien; Mazin Abdulmunem, Oday; Del Pino, Pablo; Pelaz, Beatriz; Parak, Wolfgang J; Zhang, Qian; Zhang, Huaiwu

    2017-04-10

    This paper presents a significant effect of manganese ferrite nanoparticles (MnFe2O4 NPs) on the increase of the surface photoconductivity of semiconductors. Herein, the optical characterization of photo-excited carriers of silicon coated with MnFe2O4 NPs was studied by using THz time-domain spectroscopy (THz-TDs). We observed that silicon coated with MnFe2O4 NPs provided a significantly enhanced attenuation of THz radiation in comparison with bare silicon substrates under laser irradiation. The experimental results were assessed in the context of a surface band structure model of semiconductors. In addition, photoconductive antennas coated with MnFe2O4 NPs significantly improved the efficiency of THz radiation generation and signal to noise ratio of the THz signal. This work demonstrates that coating with MnFe2O4 NPs could improve the overall performance of THz systems, and MnFe2O4 NPs could be further used for the implementation of novel optical devices.

  11. Magnetic phase transitions in ferrite nanoparticles characterized by electron spin resonance

    SciTech Connect

    Flores-Arias, Yesica Vázquez-Victorio, Gabriela; Ortega-Zempoalteca, Raul; Acevedo-Salas, Ulises; Valenzuela, Raul; Ammar, Souad

    2015-05-07

    Ferrite magnetic nanoparticles in the composition Zn{sub 0.7}Ni{sub 0.3}Fe{sub 2}O{sub 4} were synthesized by the polyol method, with an average size of 8 nm. Electron spin resonance (ESR) measurements were carried out at a frequency of 9.45 GHz in the 100–500 K temperature range. Obtained results exhibited a characteristic ESR signal in terms of resonance field, H{sub res}, linewidth, ΔH, and peak ratio, R, for each magnetic phase. At low temperatures, the ferrimagnetic phase showed low H{sub res}, broad ΔH, and asymmetric R. At high temperatures, these parameters exhibited opposite values: high H{sub res}, small ΔH, and R ∼ 1. For intermediate temperatures, a different phase was observed, which was identified as a superparamagnetic phase by means of zero-field cooling-field cooling and hysteresis loops measurements. The observed differences were explained in terms of the internal fields and especially due to the cubic anisotropy in the ordered phase.

  12. Assessment of Immunotoxicity of Dextran Coated Ferrite Nanoparticles in Albino Mice

    PubMed Central

    Syama, Santhakumar; Gayathri, Viswanathan; Mohanan, Parayanthala Valappil

    2015-01-01

    In this study, dextran coated ferrite nanoparticles (DFNPs) of size <25 nm were synthesized, characterized, and evaluated for cytotoxicity, immunotoxicity, and oxidative stress by in vitro and in vivo methods. Cytotoxicity was performed in vitro using splenocytes with different concentrations of DFNPs. Gene expression of selected cytokines (IL-1, IL-10, and TNF β) secretion by splenocytes was evaluated. Also, 100 mg of DFNPs was injected intraperitoneally to 18 albino mice for immunological stimulations. Six animals each were sacrificed at the end of 7, 14, and 21 days. Spleen was subjected to immunotoxic response and liver was analyzed for antioxidant parameters (lipid peroxidation, reduced glutathione, glutathione peroxidase, superoxide dismutase, and glutathione reductase). The results indicated that DFNPs failed to induce any immunological reactions and no significant alternation in antioxidant defense mechanism. Also, mRNA expression of the cytokines revealed an increase in IL-10 expression and subsequent decreased expression of IL-1 and TNF β. Eventually, DNA sequencing of liver actin gene revealed base alteration in nonconserved regions (10–20 bases) of all the treated groups when compared to control samples. Hence, it can be concluded that the DFNPs were nontoxic at the cellular level and nonimmunotoxic when exposed intraperitoneally to mice. PMID:26576301

  13. Monitoring Endothelial and Tissue Responses to Cobalt Ferrite Nanoparticles and Hybrid Hydrogels

    PubMed Central

    Terzuoli, Erika; Donnini, Sandra; Uva, Marianna; Ziche, Marina; Morbidelli, Lucia

    2016-01-01

    Iron oxide nanoparticles (NPs) have been proposed for many biomedical applications as in vivo imaging and drug delivery in cancer treatment, but their toxicity is an ongoing concern. When NPs are intravenously administered, the endothelium represents the first barrier to tissue diffusion/penetration. However, there is little information about the biological effects of NPs on endothelial cells. In this work we showed that cobalt-ferrite (CoFe2O4) NPs affect endothelial cell integrity by increasing permeability, oxidative stress, inflammatory profile and by inducing cytoskeletal modifications. To overcome these problems, NPs have be loaded into biocompatible gels to form nanocomposite hybrid material (polysaccharide hydrogels containing magnetic NPs) that can be further conjugated with anticancer drugs to allow their release close to the target. The organic part of hybrid biomaterials is a carboxymethylcellulose (CMC) polymer, while the inorganic part consists of CoFe2O4 NPs coated with (3-aminopropyl)trimethoxysilane. The biological activity of these hybrid hydrogels was evaluated in vitro and in vivo. Our findings showed that hybrid hydrogels, instead of NPs alone, were not toxic on endothelial, stromal and epithelial cells, safe and biodegradable in vivo. In conclusion, biohydrogels with paramagnetic NPs as cross-linkers can be further exploited for antitumor drug loading and delivery systems. PMID:28036325

  14. Enhanced Terahertz Radiation Generation of Photoconductive Antennas Based on Manganese Ferrite Nanoparticles

    PubMed Central

    Lai, Weien; Mazin Abdulmunem, Oday; del Pino, Pablo; Pelaz, Beatriz; Parak, Wolfgang J.; Zhang, Qian; Zhang, Huaiwu

    2017-01-01

    This paper presents a significant effect of manganese ferrite nanoparticles (MnFe2O4 NPs) on the increase of the surface photoconductivity of semiconductors. Herein, the optical characterization of photo-excited carriers of silicon coated with MnFe2O4 NPs was studied by using THz time-domain spectroscopy (THz-TDs). We observed that silicon coated with MnFe2O4 NPs provided a significantly enhanced attenuation of THz radiation in comparison with bare silicon substrates under laser irradiation. The experimental results were assessed in the context of a surface band structure model of semiconductors. In addition, photoconductive antennas coated with MnFe2O4 NPs significantly improved the efficiency of THz radiation generation and signal to noise ratio of the THz signal. This work demonstrates that coating with MnFe2O4 NPs could improve the overall performance of THz systems, and MnFe2O4 NPs could be further used for the implementation of novel optical devices. PMID:28393855

  15. Monitoring Endothelial and Tissue Responses to Cobalt Ferrite Nanoparticles and Hybrid Hydrogels.

    PubMed

    Finetti, Federica; Terzuoli, Erika; Donnini, Sandra; Uva, Marianna; Ziche, Marina; Morbidelli, Lucia

    2016-01-01

    Iron oxide nanoparticles (NPs) have been proposed for many biomedical applications as in vivo imaging and drug delivery in cancer treatment, but their toxicity is an ongoing concern. When NPs are intravenously administered, the endothelium represents the first barrier to tissue diffusion/penetration. However, there is little information about the biological effects of NPs on endothelial cells. In this work we showed that cobalt-ferrite (CoFe2O4) NPs affect endothelial cell integrity by increasing permeability, oxidative stress, inflammatory profile and by inducing cytoskeletal modifications. To overcome these problems, NPs have be loaded into biocompatible gels to form nanocomposite hybrid material (polysaccharide hydrogels containing magnetic NPs) that can be further conjugated with anticancer drugs to allow their release close to the target. The organic part of hybrid biomaterials is a carboxymethylcellulose (CMC) polymer, while the inorganic part consists of CoFe2O4 NPs coated with (3-aminopropyl)trimethoxysilane. The biological activity of these hybrid hydrogels was evaluated in vitro and in vivo. Our findings showed that hybrid hydrogels, instead of NPs alone, were not toxic on endothelial, stromal and epithelial cells, safe and biodegradable in vivo. In conclusion, biohydrogels with paramagnetic NPs as cross-linkers can be further exploited for antitumor drug loading and delivery systems.

  16. Evaluation of humidity sensing properties of TMBHPET thin film embedded with spinel cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Zafar, Qayyum; Azmer, Mohamad Izzat; Al-Sehemi, Abdullah G.; Al-Assiri, Mohammad S.; Kalam, Abul; Sulaiman, Khaulah

    2016-07-01

    In this study, we report the enhanced sensing parameters of previously reported TMBHPET-based humidity sensor. Significant improved sensing performance has been demonstrated by coupling of TMBHPET moisture sensing thin film with cobalt ferrite nanoparticles (synthesized by eco-benign ultrasonic method). The mean size of CoFe2O4 nanoparticles has been estimated to be 6.5 nm. It is assumed that the thin film of organic-ceramic hybrid matrix (TMBHPET:CoFe2O4) is a potential candidate for humidity sensing utility by virtue of its high specific surface area and porous surface morphology (as evident from TEM, FESEM, and AFM images). The hybrid suspension has been drop-cast onto the glass substrate with preliminary deposited coplanar aluminum electrodes separated by 40 µm distance. The influence of humidity on the capacitance of the hybrid humidity sensor (Al/TMBHPET:CoFe2O4/Al) has been investigated at three different frequencies of the AC applied voltage ( V rms 1 V): 100 Hz, 1 kHz, and 10 kHz. It has been observed that at 100 Hz, under a humidity of 99 % RH, the capacitance of the sensor increased by 2.61 times, with respect to 30 % RH condition. The proposed sensor exhibits significantly improved sensitivity 560 fF/ % RH at 100 Hz, which is nearly 7.5 times as high as that of pristine TMBHPET-based humidity sensor. Further, the capacitive sensor exhibits improved dynamic range (30-99 % RH), small hysteresis ( 2.3 %), and relatively quicker response and recovery times ( 12 s, 14 s, respectively). It is assumed that the humidity response of the sensor is associated with the diffusion kinetics of water vapors and doping of the semiconductor nanocomposite by water molecules.

  17. Enhanced biomedical heat-triggered carriers via nanomagnetism tuning in ferrite-based nanoparticles

    NASA Astrophysics Data System (ADS)

    Angelakeris, M.; Li, Zi-An; Hilgendorff, M.; Simeonidis, K.; Sakellari, D.; Filippousi, M.; Tian, H.; Van Tendeloo, G.; Spasova, M.; Acet, M.; Farle, M.

    2015-05-01

    Biomedical nanomagnetic carriers are getting a higher impact in therapy and diagnosis schemes while their constraints and prerequisites are more and more successfully confronted. Such particles should possess a well-defined size with minimum agglomeration and they should be synthesized in a facile and reproducible high-yield way together with a controllable response to an applied static or dynamic field tailored for the specific application. Here, we attempt to enhance the heating efficiency in magnetic particle hyperthermia treatment through the proper adjustment of the core-shell morphology in ferrite particles, by controlling exchange and dipolar magnetic interactions at the nanoscale. Thus, core-shell nanoparticles with mutual coupling of magnetically hard (CoFe2O4) and soft (MnFe2O4) components are synthesized with facile synthetic controls resulting in uniform size and shell thickness as evidenced by high resolution transmission electron microscopy imaging, excellent crystallinity and size monodispersity. Such a magnetic coupling enables the fine tuning of magnetic anisotropy and magnetic interactions without sparing the good structural, chemical and colloidal stability. Consequently, the magnetic heating efficiency of CoFe2O4 and MnFe2O4 core-shell nanoparticles is distinctively different from that of their counterparts, even though all these nanocrystals were synthesized under similar conditions. For better understanding of the AC magnetic hyperthermia response and its correlation with magnetic-origin features we study the effect of the volume ratio of magnetic hard and soft phases in the bimagnetic core-shell nanocrystals. Eventually, such particles may be considered as novel heating carriers that under further biomedical functionalization may become adaptable multifunctional heat-triggered nanoplatforms.

  18. Effects of Mg substitution on the structural and magnetic properties of Co0.5Ni0.5-x Mg x Fe2O4 nanoparticle ferrites

    NASA Astrophysics Data System (ADS)

    R, M. Rosnan; Z, Othaman; R, Hussin; Ali, A. Ati; Alireza, Samavati; Shadab, Dabagh; Samad, Zare

    2016-04-01

    In this study, nanocrystalline Co-Ni-Mg ferrite powders with composition Co0.5Ni0.5-x Mg x Fe2O4 are successfully synthesized by the co-precipitation method. A systematic investigation on the structural, morphological and magnetic properties of un-doped and Mg-doped Co-Ni ferrite nanoparticles is carried out. The prepared samples are characterized using x-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and vibrating sample magnetometry (VSM). The XRD analyses of the synthesized samples confirm the formation of single-phase cubic spinel structures with crystallite sizes in a range of ˜ 32 nm to ˜ 36 nm. The lattice constant increases with increasing Mg content. FESEM images show that the synthesized samples are homogeneous with a uniformly distributed grain. The results of IR spectroscopy analysis indicate the formation of functional groups of spinel ferrite in the co-precipitation process. By increasing Mg2+ substitution, room temperature magnetic measurement shows that maximum magnetization and coercivity increase from ˜ 57.35 emu/g to ˜ 61.49 emu/g and ˜ 603.26 Oe to ˜ 684.11 Oe (1 Oe = 79.5775 A·m-1), respectively. The higher values of magnetization M s and M r suggest that the optimum composition is Co0.5Ni0.4Mg0.1Fe2O4 that can be applied to high-density recording media and microwave devices. Project supported by the Ibnu Sina Institute for Scientific and Industrial Research, Physics Department of Universiti Teknologi Malaysia and the Ministry of Education Malaysia (Grant Nos. Q.J130000.2526.04H65).

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

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

    PubMed

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

    2009-05-06

    Mn ferrite (MnFe(2)O(4)) nanoparticles, having diameters from 4 to 50 nm, were synthesized using a modified co-precipitation technique in which mixed metal chloride solutions were added to different concentrations of boiling NaOH solutions to control particle growth rate. Thermomagnetization measurements indicated an increase in Néel temperature corresponding to increased particle growth rate and particle size. The Néel temperature is also found to increase inversely proportionally to the cation inversion parameter, delta, appearing in the formula (Mn(1-delta)Fe(delta))(tet)[Mn(delta)Fe(2-delta)](oct)O(4). These results contradict previously published reports of trends between Néel temperature and particle size, and demonstrate the dominance of cation inversion in determining the strength of superexchange interactions and subsequently Néel temperature in ferrite systems. The particle surface chemistry, structure, and magnetic spin configuration play secondary roles.

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

    PubMed

    Yaseneva, Polina; Bowker, Michael; Hutchings, Graham

    2011-11-07

    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.

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

    PubMed

    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

    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

  3. 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)

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

    2010-12-01

    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 (Φf) 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) (ΦΔ = 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 μmol.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.

  4. Positron annihilation and magnetic properties studies of copper substituted nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kargar, Z.; Asgarian, S. M.; Mozaffari, M.

    2016-05-01

    Single phase copper substituted nickel ferrite Ni1-xCuxFe2O4 (x = 0.0, 0.1, 0.3 and 0.5) nanoparticles were synthesized by the sol-gel method. TEM images of the samples confirm formation of nano-sized particles. The Rietveld refinement of the X-ray diffraction patterns showed that lattice constant increase with increase in copper content from 8.331 for x = 0.0 to 8.355 Å in x = 0.5. Cation distribution of samples has been determined by the occupancy factor, using Rietveld refinement. The positron lifetime spectra of the samples were convoluted into three lifetime components. The shortest lifetime is due to the positrons that do not get trapped by the vacancy defects. The second lifetime is ascribed to annihilation of positrons in tetrahedral (A) and octahedral (B) sites in spinel structure. It is seen that for x = 0.1 and 0.3 samples, positron trapped within vacancies in A sites, but for x = 0.0 and 0.5, the positrons trapped and annihilated within occupied B sites. The longest lifetime component attributed to annihilation of positrons in the free volume between nanoparticles. The obtained results from coincidence Doppler broadening spectroscopy (CDBS) confirmed the results of positron annihilation lifetime spectroscopy (PALS) and also showed that the vacancy clusters concentration for x = 0.3 is more than those in other samples. Average defect density in the samples, determined from mean lifetime of annihilated positrons reflects that the vacancy concentration for x = 0.3 is maximum. The magnetic measurements showed that the saturation magnetization for x = 0.3 is maximum that can be explained by Néel's theory. The coercivity in nanoparticles increased with increase in copper content. This increase is ascribed to the change in anisotropy constant because of increase of the average defect density due to the substitution of Cu2+ cations and magnetocrystalline anisotropy of Cu2+ cations. Curie temperature of the samples reduces with increase in copper content which

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  6. Bimetallic nanoparticles: Preparation, properties, and biomedical applications.

    PubMed

    Nasrabadi, Hamid Tayefi; Abbasi, Elham; Davaran, Soodabeh; Kouhi, Mohammad; Akbarzadeh, Abolfazl

    2016-01-01

    Many studies of non-supported bimetallic nanoparticle (BMNP) dispersions, stabilized by ligands or polymers, and copolymers, were started only about 10 years ago. Several preparative procedures have been proposed, and full characterizations on BMNPs have been approved. Studies on BMNPs received huge attention from both scientific and technological communities because most of the NPs' catalytic activity depends on their structural aspects. In this study, we focus on the preparation, properties, and bio-application of BMNPs and introduction of the recent advance in these NPs.

  7. Load partitioning between ferrite/martensite and dispersed nanoparticles of a 9Cr ferritic/martensitic (F/M) ODS steel at high temperatures

    SciTech Connect

    Zhang, Guangming; Mo, Kun; Miao, Yinbin; Liu, Xiang; Almer, Jonathan; Zhou, Zhangjian; Stubbins, James F.

    2015-06-18

    In this study, a high-energy synchrotron radiation X-ray technique was used to investigate the tensile deformation processes of a 9Cr-ODS ferritic/martensitic (F/M) steel at different temperatures. Two minor phases within the 9Cr-ODS F/M steel matrix were identified as Y2Ti2O7 and TiN by the high-energy X-ray diffraction, and confirmed by the analysis using energy dispersive X-ray spectroscopy (EDS) of scanning transmission electron microscope (STEM). The lattice strains of the matrix and particles were measured through the entire tensile deformation process. During the tensile tests, the lattice strains of the ferrite/martensite and the particles (TiN and Y2Ti2O7) showed a strong temperature dependence, decreasing with increasing temperature. Analysis of the internal stress at three temperatures showed that the load partitioning between the ferrite/martensite and the particles (TiN and Y2Ti2O7) was initiated during sample yielding and reached to a peak during sample necking. At three studied temperatures, the internal stress of minor phases (Y2Ti2O7 and TiN) was about 2 times that of F/M matrix at yielding position, while the internal stress of Y2Ti2O7 and TiN reached about 4.5-6 times and 3-3.5 times that of the F/M matrix at necking position, respectively. It indicates that the strengthening of the matrix is due to minor phases (Y2Ti2O7 and TiN), especially Y2Ti2O7 particles. Although the internal stresses of all phases decreased with increasing temperature from RT to 600 degrees C, the ratio of internal stresses of each phase at necking position stayed in a stable range (internal stresses of Y2Ti2O7 and TiN were about 4.5-6 times and 3-3.5 times of that of F/M matrix, respectively). The difference between internal stress of the F/M matrix and the applied stress at 600 degrees C is slightly lower than those at RI and 300 degrees C, indicating that the nanoparticles still have good strengthening effect at 600 degrees C. (C) 2015 Elsevier B.V. All rights reserved.

  8. A novel low-temperature preparation of Ni-Zn ferrite and the properties of the ultrafine particles formed

    NASA Astrophysics Data System (ADS)

    Chen, C. J.; Bridger, K.; Winzer, S. R.; PaiVerneker, V.

    1988-04-01

    Ultrafine particles of nickel-zinc ferrite have been formed from solutions of metal nitrates by coprecipitation with hydrazine, followed by aging at 90 °C. The crystallites either aggregate into much larger clusters or form single particles, depending upon the preparation conditions, and vary in size from 30 to ≊300 Å. Saturation magnetizations (Ms) of the ferrites varied from 40 to 65 emu/g and the coercivities from 1 to ≊100 Oe. Increasing hydrazine concentrations tended to produce particles with lower Ms. However, for hydrazine/metal ratios below unity, decreasing the hydrazine concentration dramatically lowered the Ms value. Particles formed without hydrazine (e.g., by aging hydroxides precipitated with potassium hydroxide) did not appear to be magnetic. Variations of the magnetic properties and lattice parameters as a function of preparation conditions will be discussed.

  9. Comparison of structural and electrical properties of Co{sup 2+}doped Mn-Zn soft nano ferrites prepared via coprecipitation and hydrothermal methods

    SciTech Connect

    Anwar, Humaira; Maqsood, Asghari

    2014-01-01

    Graphical abstract: - Highlights: • Coprecipitation and hydrothermal synthesis of Co{sup 2+} doped Mn-Zn ferrites. • Dielectric measurements at 3 MHz and 1 GHz frequencies. • Enhanced DC electrical resistivity for samples prepared from hydrothermal technique. • Impedance studies for the prepared samples showing major contribution due to grains. - Abstract: A series of Co doped Mn-Zn ferrites compounds with the formula Mn{sub 0.5}Zn{sub 0.5−x}Co{sub x}Fe{sub 2}O{sub 4} (x = 0, 0.15, 0.25, 0.35 and 0.50) were successfully synthesized by polyethylene glycol-assisted coprecipitation and hydrothermal methods. The structural characterization of the samples was done using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). All the samples found to have cubic spinel structure. The average crystallite size of all nanoparticles were estimated using Scherrer's formula and found to lie between 10 and 25 ± 3 nm with small size distribution of particles prepared by hydrothermal method. The FTIR spectrum showed two absorption bands of tetrahedral and octahedral metal-oxygen sites. DC electrical resistivity varied from 4.12 × 10{sup 7} to 8.32 × 10{sup 10} ohm cm with cobalt doping. The dielectric measurements were performed from 20 Hz to 3 MHz and from 1 MHz to 1 GHz frequency ranges. The value of dielectric constant (ε′) varies from 15.54 to 106.25 (1 MHz) and 6.73–16.48 (1 GHz) for all the samples at room temperature. Impedance spectroscopy was carried out from 20 Hz to 3 MHz, at room temperature to study the grains and grain boundaries effect.

  10. Study the spin configuration and the saturation magnetization of manganese-zinc ferrite nanoparticles by the Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Rodionov, V. A.; Zhuravlev, V. A.

    2017-01-01

    In this work, the simulations of magnetic properties of nano-sized manganese ferrite particles with zinc replacement were performed. The percentage of replacement laid in range from 0% to 80%. The parameters of particles, including exchange integrals, were taken from experimental data received for MnxZn1-xFe2O4. The sizes of particles and thickness of defective surface layer were taken, taking into account real sizes distribution for manganese nanoparticles received by the way of mechanochemical synthesis. Simulations were performed using the Monte-Carlo methods, Metropolis algorithm.

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

    PubMed

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

    2012-06-15

    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.

  12. Comparing highly ordered monolayers of nanoparticles fabricated using electrophoretic deposition: Cobalt ferrite nanoparticles versus iron oxide nanoparticles

    DOE PAGES

    Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; ...

    2015-08-01

    Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

  13. Effect of UV radiations to control particle size of Mn-Zn spinel ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Ameen Ramiza, F.; Ajmal, S. K.; Khan, M. B.; Nasim, A.; Jamil, Y.; Kashif, K.; Amira, S.

    2016-08-01

    MnxZn1-xFe2O4 (0.0 < x < 1.0) ferrite nano particles were synthesized for concentration varying from 0.27 to 0.87 to obtain chemically homogenous powder for obtaining fine particle size by co precipitation technique. Keeping in view the interest of scientists for particle size, the present work focus on the impact of UV radiation to control the particle size of prepared fine magnetic particles. The particles were digested for ninety minutes at a temperature of 90oC. The samples were divided into four equal quantities and were subjected to different doses of UV radiation. The chemically produced samples of Mn-Zn ferrite nano particles were analyzed by XRD which confirmed cubic spinel structure of the material. The average crystallite size (t), lattice parameter (a) and other structural parameters of UV-irradiated MnxZni-xFe2O4 spinel ferrite were calculated from XRD data. The spinel peak of the irradiated sample when compared with the control sample, shifted from 35.38 to 35.15. In few samples, additional peaks supporting the ferrite structure were also observed. The variation in the particle sizes observed for various doses of UV irradiation were in the range of 17.6 to 6.2 nm, whereas the particle size of the control was 8.82nm. The experiment was repeated for different concentrations, at the same digestion temperature and time revealed the similar results indicating that UV radiations can have a remarkable effect to control the phase and size of nano size fine magnetic ferrite particles. The present work successfully document the impact of UV to control the particle size.

  14. Fabrication of silver-coated cobalt ferrite nanocomposite and the study of its antibacterial activity

    NASA Astrophysics Data System (ADS)

    Kooti, M.; Saiahi, S.; Motamedi, H.

    2013-05-01

    A new silver coated cobalt ferrite nanocomposite, Ag@CoFe2O4, was prepared by a two-step procedure. In the first step, cobalt ferrite nanoparticles were synthesized by a combustion method using glycine as a fuel. This ferrite was then coated with nanosilver via chemical reduction of Ag+ solution. The as-synthesized Ag@CoFe2O4 was characterized by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The antibacterial activity of this composite was investigated against some Gram-positive and Gram-negative bacteria and compared with those of silver nanoparticles and some standard antibacterial drugs.

  15. Oriented Y-type hexagonal ferrite thin films prepared by chemical solution deposition

    SciTech Connect

    Buršík, J.; Kužel, R.; Knížek, K.; Drbohlav, I.

    2013-07-15

    Thin films of Ba{sub 2}Zn{sub 2}Fe{sub 12}O{sub 22} (Y) hexaferrite were prepared through the chemical solution deposition method on SrTiO{sub 3}(1 1 1) (ST) single crystal substrates using epitaxial SrFe{sub 12}O{sub 19} (M) hexaferrite thin layer as a seed template layer. The process of crystallization was mainly investigated by means of X-ray diffraction and atomic force microscopy. A detailed inspection revealed that growth of seed layer starts through the break-up of initially continuous film into isolated grains with expressive shape anisotropy and hexagonal habit. The vital parameters of the seed layer, i.e. thickness, substrate coverage, crystallization conditions and temperature ramp were optimized with the aim to obtain epitaxially crystallized Y phase. X-ray diffraction Pole figure measurements and Φ scans reveal perfect parallel in-plane alignment of SrTiO{sub 3} substrate and both hexaferrite phases. - Graphical abstract: XRD pole figure and AFM patterns of Ba{sub 2}Zn{sub 2}Fe{sub 12}O{sub 22} thin film epitaxially grown on SrTiO{sub 3}(1 1 1) single crystal using seeding layer templating. - Highlights: • Single phase Y-type hexagonal ferrite thin films were prepared by CSD method. • Seed M layer breaks into isolated single crystal islands and serves as a template. • Large seed grains grow by consuming the grains within the bulk of recoated film. • We explained the observed orientation relation of epitaxial domains. • Epitaxial growth on SrTiO{sub 3}(1 1 1) with relation (0 0 1){sub M,Y}//(1 1 1){sub ST}+[1 0 0]{sub M,Y}//[2 −1 −1]{sub ST}.

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

    NASA Astrophysics Data System (ADS)

    Batoo, Khalid Mujasam; Ansari, Mohammad Shahnawaze

    2012-02-01

    Ferrite nanoparticles of basic composition Ni0.7- x Zn x Cu0.3Fe2O4 (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 ( v 1 and v 2) 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 ( ɛ', ɛ″, tan δ, and σ 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.

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

    PubMed Central

    2012-01-01

    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 (ε', ε″, tanδ, and σac) 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

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

    PubMed

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

    2015-03-01

    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.

  19. Gadolinium substitution effect on the thermomagnetic properties of Ni ferrite ferrofluids

    NASA Astrophysics Data System (ADS)

    Jacobo, Silvia E.; Arana, Mercedes; Bercoff, Paula G.

    2016-10-01

    This work is focused on the structural and magnetic characterization of Gd-doped Ni ferrite nanoparticles and the preparation of a ferrofluid for applications in heat-transfer devices. For this purpose, spinel ferrites NiFe2O4, and NiFe1.88Gd0.12O4 were prepared by the self-combustion method. The substituted sample was obtained with a small amount of Gd inclusion and the excess appeared as GdFeO3. The smallest nanoparticles of both samples were properly coated and dispersed in kerosene. Thermal conductivities of the produced ferrofluids were measured at 25 °C under an applied magnetic field. There is a significant enhancement in the thermal conductivity of the ferrofluid prepared with NiGd ferrite with respect to the one with Ni ferrite, in presence of a magnetic field. This effect is directly related to the well-known magnetocaloric effect of Gd.

  20. Antimicrobial Lemongrass Essential Oil-Copper Ferrite Cellulose Acetate Nanocapsules.

    PubMed

    Liakos, Ioannis L; Abdellatif, Mohamed H; Innocenti, Claudia; Scarpellini, Alice; Carzino, Riccardo; Brunetti, Virgilio; Marras, Sergio; Brescia, Rosaria; Drago, Filippo; Pompa, Pier Paolo

    2016-04-20

    Cellulose acetate (CA) nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG) essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs), with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities.

  1. Nonstoichiometry and phase stability of Al and Cr substituted Mg ferrite nanoparticles synthesized by citrate method

    NASA Astrophysics Data System (ADS)

    Ateia, Ebtesam. E.; Mohamed, Amira. T.

    2017-03-01

    The spinel ferrite Mg0.7Cr0.3Fe2O4, and Mg0.7Al0.3Fe2O4 were prepared by the citrate technique. All samples were characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Micrographs (HRTEM), Energy Dispersive X ray Spectroscopy (EDAX) and Atomic Force Microscope (AFM). XRD confirmed the formation of cubic spinel structure of the investigated samples. The average crystallite sizes were found to be between 24.7 and 27.5 nm for Al3+ and Mg2+ respectively. The substitution of Cr3+/Al3+ in place of Mg2+ ion initiates a crystalline anisotropy due to large size mismatch between Cr /Al and Mg2+, which creates strain inside the crystal volume. According to VSM results, by adding Al3+ or Cr3+ ions at the expense of Mg2+, the saturation magnetization increased. The narrow hysteresis loop of the samples indicates that the amount of dissipated energy is small, which is desirable for soft magnetic applications. Magnetic dynamics of the samples were studied by measuring magnetic susceptibility versus temperature at different magnetic fields. The band gap energy, which was calculated from near infrared (NIR) and visible (VIS) reflectance spectra using the Kubelka-Munk function, decreases with increasing the particle size. Furthermore, the band gaps were quite narrow (1.5-1.7 eV), hence the investigated samples could act as visible light driven photo catalysts. To sum up the addition of trivalent Al3+, and Cr3+ ions enhanced the optical, magnetic and structure properties of the samples. Mg0.7 Cr0.3Fe2O4 sample will be a better candidate for the optical applications and will also be a guaranteeing hopeful for technological applications.

  2. 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.

    PubMed

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

    2011-07-29

    The synthesis and properties of Mg((x))Zn((1 - x))Fe(2)O(4) spinel ferrites as a low-toxicity alternative to the technologically significant Ni((x))Zn((1 - x))Fe(2)O(4) 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))Fe(2)O(4) 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.

  3. 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)

    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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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

  5. Structure and magnetic properties of Co and Ni nano-ferrites prepared by a two step direct microemulsions synthesis

    NASA Astrophysics Data System (ADS)

    Pulišová, P.; Kováč, J.; Voigt, A.; Raschman, P.

    2013-09-01

    Nano-particles of CoFe2O4, NiFe2O4 and Co0.5Ni0.5Fe2O4 were synthesized by a two step microemulsion precipitation where inverse micelles of water in hexanol were stabilized using cetyltrimethylammonium bromide. Powder X-ray diffraction analysis and Transmission electron microscopy measurements provided data to clarify the crystal structure and size of the produced nano-particles. Different measurements of magnetic properties at low temperatures of 2 K revealed that nano-particles of NiFe2O4 represent magnetically soft ferrite with a coercivity ∼40 kA/m, whereas nano-particles of CoFe2O4 and Co0.5Ni0.5Fe2O4 were magnetically harder with a coercivity of 815 and 947 kA/m, respectively. Additionally zero field cooling and field cooling measurements provided data for estimating the blocking temperature of the materials produced. For NiFe2O4 this temperature is lower, 23 K. The blocking temperature of CoFe2O4 of 238 K and Co0.5Ni0.5Fe2O4 of 268 K are higher in comparison with NiFe2O4.

  6. Influence of various surfactants on magnetic property of cobalt ferrite prepared by Co-precipitation technique

    NASA Astrophysics Data System (ADS)

    Solanki, Neha; Khatri, Hemal; Jotania, R. B.

    2016-05-01

    Cobalt Ferrite (CoFe2O4) particles were synthesised using a Co-precipitation method. Influence of three different surfactants i.e. (1) Cationic - CTAB (Cetyl Tri-Methyl Ammonium Bromide), (2) Anionic - SDBS (Sodium Dodecyl Benzene Sulphonate) and (3) Nonionic - Triton X-100, on magnetic property of Cobalt Ferrite were investigated. Magnetic property of Cobalt ferrite powder was studied at room temperature using Vibrating Sample Measurements (VSM) technique under an applied magnetic field of 15kOe. The results show maximum value of saturation magnetization - Ms (81.87 emu/g) for the sample synthesised without surfactant and Coercivity value found maximum (2086 kOe) for the sample synthesized in presence of surfactant SDBS.

  7. Preparation of Copper Nanoparticles in Liquid by Matrix Sputtering Process

    NASA Astrophysics Data System (ADS)

    Nakagawa, Ko; Narushima, Takashi; Udagawa, Satoshi; Yonezawa, Tetsu

    2013-03-01

    As a new method for nanoparticles preparation, magnetron sputtering of metal atoms and clusters into organic liquids has been intensively used recently. In this study, metallic copper nanoparticles dispersed in pentaerythritol ethoxylate were prepared by this process. Their size control was achieved by controlling the sputtering current. Specific absorption at ca. 580 nm was detected by UV-Vis measurement which is attributed to the specific plasmon absorption of metallic copper. TEM observation also revealed the formation of metallic nanoparticles.

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

    SciTech Connect

    Kahn, Myrtil L.; Zhang, Z. John

    2001-06-04

    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.

  9. Self-Assembly of an Optically-Responsive Polydiacetylene-Coating on Iron Ferrite Magnetic Nanoparticles for Tumor Detection and Targeting

    NASA Astrophysics Data System (ADS)

    Le, Vivian

    Nanoparticles are a promising diagnostic agent with applications in tumor imaging and targeted cancer treatment. They can offer multifunctional properties by combining imaging methods to improve cancer diagnosis, treatment, and disease monitoring. Two such complementary tools are magnetic resonance imaging (MRI) and fluorescence imaging. In this thesis, a dual solvent exchange approach was chosen to facilitate the self-assembly of amphiphilic diacetylene monomers onto hydrophobic iron ferrite magnetic nanoparticles (MNPs). Various concentrations of the diacetylene monomers, 10,12-pentacosadiynoic acid (PCDA) and 10,12-heptacosadiynoic acid (HCDA), were coated onto ˜14 nm iron ferrite MNPs. The diacetylene monomer coating were cross-linked to a stable blue colored polydiacetylene (PDA) coating after applying UV light. The resulting PDA-MNP hybrid displayed characteristic chromogenic and fluorogenic in response to thermal stress. This novel multifunctional nanoparticle system holds exciting potential for dual-modality diagnostics applications.

  10. Effect of pH value on electromagnetic loss properties of Co-Zn ferrite prepared via coprecipitation method

    NASA Astrophysics Data System (ADS)

    Huang, Xiaogu; Zhang, Jing; Wang, Wei; Sang, Tianyi; Song, Bo; Zhu, Hongli; Rao, Weifeng; Wong, Chingping

    2016-05-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9-11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9-11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02-0.07 and magnetic loss factor was 0.2-0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials.

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

    PubMed

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

    2011-07-20

    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.

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

    PubMed Central

    2011-01-01

    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

  13. Synthesis and magnetic characterization of cobalt-substituted ferrite (Co xFe 3-xO 4) nanoparticles

    NASA Astrophysics Data System (ADS)

    Calero-DdelC, Victoria L.; Rinaldi, Carlos

    2007-07-01

    Cobalt-substituted ferrite nanoparticles were synthesized with a narrow size distribution using reverse micelles formed in the system water/AOT/isooctane. Fe:Co ratios of 3:1, 4:1, and 5:1 were used in the synthesis, obtaining cobalt-substituted ferrites (Co xFe 3-xO 4) and some indication of γ-Fe 3O 4 when 4:1 and 5:1 Fe:Co ratios were used. Inductively coupled plasma mass spectroscopy (ICP-MS) verified the presence of cobalt in all samples. Fourier transform infrared (FTIR) showed bands at ˜560 and ˜400 cm -1, characteristic of the metal-oxygen bond in ferrites. Transmission electron microscopy showed that the number median diameter of the particles was ˜3 nm with a geometric deviation of ˜0.2. X-ray diffraction (XRD) confirmed the inverse spinel structure typical of ferrites with a lattice parameter of a=8.388 Å for Co 0.61Fe 0.39O 4, which is near that of CoFe 2O 4 ( a=8.394 Å). Magnetic properties were determined using a superconducting quantum interference device (SQUID). Coercivities higher than 8 kOe were observed at 5 K, whereas at 300 K the particles showed superparamagnetic behavior. The anisotropy constant was determined based on the Debye model for a magnetic dipole in an oscillating field and an expression relating χ' and the temperature of the in-phase susceptibility peak. Anisotropy constant values in the order of ˜10 6 erg/cm 3 were determined using the Debye model, whereas anisotropy constants in the order of ˜10 7 erg/cm 3 were calculated assuming Ωτ=1 at the temperature peak of the in-phase component of the susceptibility curve as commonly done in the literature. Our analysis demonstrates that the assumption Ωτ=1 at the temperature peak of χ' is rigorously incorrect.

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

    NASA Astrophysics Data System (ADS)

    Shahdan, Dalila; Ahmad, Sahrim Hj

    2013-05-01

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

  15. Preparation of drug nanoparticles by emulsion evaporation method

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  16. Electrochemical preparation of carbon chains and nanoparticles

    NASA Astrophysics Data System (ADS)

    Kavan, Ladislav

    1999-09-01

    The composite of carbon with alkali metal fluoride, C-MF(M=Li, Na) was prepared by cathodic defluorination of perfluorinated hydrocarbons at room temperature. Raman spectra of C-MF from PTFE indicate carbon chains (oligoynes, 1974-2024 cm-1) in addition to graphite-like carbon (1300-1500 cm-1). The oligoyne-containing carbon is partly selforganized by cross linking towards graphene. Highly-organized carbons were prepared from friction-deposited PTFE films. AFM confirms perfect ordering of the precursor molecules (up to atomic resolution), but the corresponding carbonization product is rapidly reconstructed upon contact to air. Raman spectra of oriented carbons display high conjugation lengths (up to 18 sp-bonded carbon atoms). Cyclic perfluorinated precursors are also smoothly defluorinated to elemental carbon. TEM indicates that these carbons contain about 1% of carbonaceous nanoparticles, i.e. nanotubes and onions. Also small quantity of fullerene C60(≈0.01%) was detected in the toluene extract.

  17. Volume-labeled nanoparticles and methods of preparation

    DOEpatents

    Wang, Wei; Gu, Baohua; Retterer, Scott T; Doktycz, Mitchel J

    2015-04-21

    Compositions comprising nanosized objects (i.e., nanoparticles) in which at least one observable marker, such as a radioisotope or fluorophore, is incorporated within the nanosized object. The nanosized objects include, for example, metal or semi-metal oxide (e.g., silica), quantum dot, noble metal, magnetic metal oxide, organic polymer, metal salt, and core-shell nanoparticles, wherein the label is incorporated within the nanoparticle or selectively in a metal oxide shell of a core-shell nanoparticle. Methods of preparing the volume-labeled nanoparticles are also described.

  18. 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

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

    2009-02-04

    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.

  19. Comparative study of NiFe{sub 2−x}Al{sub x}O{sub 4} ferrite nanoparticles synthesized by chemical co-precipitation and sol–gel combustion techniques

    SciTech Connect

    Gul, I.H.; Pervaiz, Erum

    2012-06-15

    Graphical abstract: AFM images of NiFe{sub 2}O{sub 4} ferrite nanoparticles at room temperature synthesized by sol–gel technique. Highlights: ► Particle size reduces to less than 30 nm. ► DC electrical resistivity increases with substitution of Cr{sup 3+}. ► Dielectric constant decreases. -- Abstract: A series of aluminum substituted Ni-ferrite nanoparticles have been synthesized by chemical co-precipitation and sol–gel techniques. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), DC electrical resistivity and dielectric properties. Analysis of the X-ray diffraction pattern of all the samples confirmed the formation of spinel structure. The crystallite sizes remain within the range 25–41 ± 3 nm. FTIR measurements show two fundamental absorption bands, assigned to the vibration of tetrahedral and octahedral sites. DC electrical resistivity increases from 6.60 × 10{sup 7} to 6.9 × 10{sup 10} Ω cm as the Al{sup 3+} concentration increases from 0.00 to 0.50. The dielectric constant and loss tangent decreases with increasing Al{sup 3+} concentration from 22 to 14, 0.354 to 0.27 respectively at 5 MHz for all the samples. Impedance measurements as a function of frequency (1 kHz–5 MHz) at room temperature further helped in analyzing the electrical properties of the prepared samples.

  20. Preparation of hollow microspheres of Ce3+ doped NiCo ferrite with high microwave absorbing performance

    NASA Astrophysics Data System (ADS)

    Duan, Hong-zhen; Zhou, Fang-ling; Cheng, Xia; Chen, Guo-hong; Li, Qiao-ling

    2017-02-01

    Hollow microspheres of Ce3+ doped NiCo-ferrites were synthesized by template-based-deposition and surface reaction method with carbon sphere as the template. The phase structure, morphology, magnetic properties and wave absorbing properties of the sample were characterized by X-ray powder diffraction(XRD), Scanning electronic microscopy(SEM), Vibration sample magnetometer (VSM) and a network vector analyzer (NVA), respectively. The results indicated that the particle size of the carbon sphere sample prepared by hydrothermal method was about 0.5 μm and the particle size of the Ni0.5Co0.5Fe2O4 sample prepared by template-based method was about 300 nm. The influence of the amount of rare earth element on the magnetic and absorbing properties of sample was studied. The saturation magnetization and coercivity decreased gradually with the increase of the content of Ce. When the content of Ce was 0.02, the maximal saturation magnetization value and coercivity was 75.72 emu•g-1 and 789.88 Oe, respectively. The associated ferrite hollow spheres have good absorbing performance, and the return loss value was -18.8 dB at 5500 MHz.

  1. Magnetic and dielectric behavior of chromium substituted Co-Mg ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Jadoun, Priya; Jyoti, Prashant, B. L.; Dolia, S. N.; Bhatnagar, D.; Saxena, V. K.

    2016-05-01

    The chromium doped Co-Mg ferrite with composition Co0.5Mg0.5Cr0.2Fe1.8O4 has been synthesized using sol-gel auto combustion method. The crystal structure has been analyzed by X-ray diffraction (XRD) technique. XRD pattern reveals the formation of single phase cubic spinel structure. The magnetic measurements show ferromagnetic behavior at room temperature and large coercivity is observed on cooling down the temperature to 20 K. Dielectric constant (ɛ') and dielectric loss tangent (tan δ) have been determined at room temperature as a function of frequency in the frequency range 75 kHz to 80 MHz. The decrease in dielectric constant with increasing frequency attributes to Maxwell Wagner model and conduction mechanism in ferrites.

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

    PubMed Central

    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

    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 β-cyclodextrin (Fe-Ni/Zn/βCD) 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/βCD 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 βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD 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/βCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn. PMID:23209524

  3. Enhanced electrical properties in Nd doped cobalt ferrite nano-particles

    NASA Astrophysics Data System (ADS)

    Abbas, S.; Munir, A.; Zahra, F.; Rehman, M. A.

    2016-08-01

    Spinel ferrites are important class of compounds which has variety of electrical, magnetic and catalytic applications. A small amount of rare earth element causes modification in structural, electrical and magnetic properties of ferrite materials for practical applications. Neodymium doped cobalt ferrites with composition CoNdxFe2-xO4 where x is 0.1 has been synthesized by sol-gel method. Sol-gel method was preferred because it has good control over stoichiometry, crystallite size and particle size distribution. Characterization was done by using X-Ray Diffraction (XRD) technique for structural analysis and crystal structure was found to be spinel. Particles like morphology was observed in micrographs obtained by Scanning Electron Microscopy (SEM). Thermal analysis of sample has been done which includes Thermogravimetric analysis (TGA) and Differential Scanning calorimetry (DSC). Fourier transform infra-red spectroscopy (FT-IR) of samples was also performed. DC resistivity as a function of temperature has been studied and its shows direct dependence on temperature and inverse dependence on the concentration of Nd dopant. The studied material is a potential candidate for resistive random access memory application.

  4. Tailoring the magnetic properties of cobalt-ferrite nanoclusters

    NASA Astrophysics Data System (ADS)

    de la Vega, A. Estrada; Garza-Navarro, M. A.; Durán-Guerrero, J. G.; Moreno Cortez, I. E.; Lucio-Porto, R.; González-González, V.

    2016-01-01

    In this contribution, we report on the tuning of magnetic properties of cobalt-ferrite nanoclusters. The cobalt-ferrite nanoclusters were synthesized from a two-step approach that consists of the synthesis of cobalt-ferrite nanoparticles in organic media, followed by their dispersion into aqueous dissolution to form an oil-in-water emulsion. These emulsions were prepared at three different concentrations of the cationic surfactant cetyltrimethylammonium bromide (CTAB), in order to control the size and clustering density of the nanoparticles in the nanoclusters. The synthesized samples were characterized by transmission electron microscopy and their related techniques, such as bright-field and Z-contrast imaging, electron diffraction and energy-dispersive X-ray spectrometry; as well as static magnetic measures. The experimental evidence indicates that the size, morphology, and nanoparticles clustering density in the nanoclusters is highly dependent of the cobalt-ferrite:CTAB molar ratio that is used in their synthesis. In addition, due to the clustering of the nanoparticles into the nanoclusters, their magnetic moments are blocked to relax cooperatively. Hence, the magnetic response of the nanoclusters can be tailored by controlling the size and nanoparticles clustering density.

  5. Preparation and Characterization of Nateglinide Loaded Hydrophobic Biocompatible Polymer Nanoparticles

    NASA Astrophysics Data System (ADS)

    Naik, Jitendra; Lokhande, Amolkumar; Mishra, Satyendra; Kulkarni, Ravindra

    2016-09-01

    The aim of the present study was to develop sustained release Nateglinide loaded Ethylcellulose nanoparticles and characterize the properties of recovered nanoparticles. The sustained release nanoparticles were prepared by oil in water single emulsion solvent evaporation method. The developed nanoparticles were characterised for their particle size, morphology, encapsulation efficiency, drug polymer compatibility and in vitro drug release. The drug polymer compatibility was investigated by XRPD. Imaging of particles was performed by field emission scanning electron microscopy. The highest particle size and encapsulation efficiency of recovered nanoparticles were 248.37 nm and 91.16 % respectively. The recovered nanoparticles are spherical in nature and uniform in size. Developed nanoparticles have low crystallinity than the pure Nateglinide. The highest drug-polymer ratio formulation showed drug release 61.1 ± 1.76 % up to 24 h.

  6. Structural, Optical and EXAFS Studies of Nickel Substituted Copper Ferrites Nano-Particle by Sol-Gel Auto Combustion Method

    NASA Astrophysics Data System (ADS)

    Mishra, Ashutosh; khan, Mehjabeen; Jarabana, Kanaka M.; Bisen, Supriya

    2016-10-01

    The Cu-Ni ferrites with general formula Cu1-xNixFe2O4 (where x=0.0, 0.1, 0.2, 0.3) were prepared by sol gel method. The Extended X-ray absorption fine structure (EXAFS), X- ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) measurements were carried out. EXAFS spectra have been recorded at the k edge of Iron using the dispersive EXAFS (DEXAFS) beam line at 2.5 GeV at Indus -2 synchrotron radiation source RRCAT, Indore, India. The EXAFS data have been analyzed using the computer software Athena. These have been used to determine the bond lengths in these ferrites with the help of three different methods, namely, Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The phase uncorrected bond lengths have also been obtained from Fourier transformation method and the results obtained have been compared with the results obtained from LSS method, which also gives phase uncorrected bond lengths. XRD shows the structure is the tetragonal, and FTIR was used to determine the nature of the vibrational modes present in the system.

  7. Fe-based soft magnetic composites coated with NiZn ferrite prepared by a co-precipitation method

    NASA Astrophysics Data System (ADS)

    Peng, Yuandong; Yi, Yi; Li, Liya; Ai, Hengyu; Wang, Xiaoxu; Chen, Lulu

    2017-04-01

    Fe powder was coated with NiZn ferrite by a co-precipitation method using chlorate as the raw material. Soft magnetic composites were manufactured via compaction and heat treatment of the coated powder. The coated powder and heat treated powder were analysed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. Their magnetic properties were determined using a Quantum Design-Vibrating Sample Magnetometer (QD-VSM). The composites were analysed with SEM and EDS. The permeability and magnetic loss of the composites were measured with a B-H curve analyzer. The results show that, using the co-precipitation method, the raw precipitate was successfully prepared and coated the pure Fe powder and turned into spinel NiZn ferrite treated at 600 ℃ for 1 h. After heat treatment at 500 ℃ under air, the insulation coating layer of soft magnetic composite (SMC) was not destroyed and containing Fe, Ni, Zn and oxygen. The permeabilities of the SMC are stable at edge of the 2-200 kHz frequency range and the total loss was lower.

  8. Preparation and characterization of porous reduced graphene oxide based inverse spinel nickel ferrite nanocomposite for adsorption removal of radionuclides.

    PubMed

    Lingamdinne, Lakshmi Prasanna; Choi, Yu-Lim; Kim, Im-Soon; Yang, Jae-Kyu; Koduru, Janardhan Reddy; Chang, Yoon-Young

    2017-03-15

    For the removal of uranium(VI) (U(VI)) and thorium(IV) (Th(IV)), graphene oxide based inverse spinel nickel ferrite (GONF) nanocomposite and reduced graphene oxide based inverse spinel nickel ferrite (rGONF) nanocomposite were prepared by co-precipitation of GO with nickel and iron salts in one pot. The spectral characterization analyses revealed that GONF and rGONF have a porous surface morphology with an average particle size of 41.41nm and 32.16nm, respectively. The magnetic property measurement system (MPMS) studies confirmed the formation of ferromagnetic GONF and superparamagnetic rGONF. The adsorption kinetics studies found that the pseudo-second-order kinetics was well tune to the U(VI) and Th(IV) adsorption. The results of adsorption isotherms showed that the adsorption of U(VI) and Th(IV) were due to the monolayer on homogeneous surface of the GONF and rGONF. The adsorptions of both U(VI) and Th(IV) were increased with increasing system temperature from 293 to 333±2K. The thermodynamic studies reveal that the U(VI) and Th(IV) adsorption onto GONF and rGONF was endothermic. GONF and rGONF, which could be separated by external magnetic field, were recycled and re-used for up to five cycles without any significant loss of adsorption capacity.

  9. 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

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

    2010-12-15

    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.

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

    PubMed

    Yu, Byong Yong; Kwak, Seung-Yeop

    2011-10-21

    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.

  11. Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

    DOE PAGES

    Parish, Chad M.; Unocic, Kinga A.; Tan, Lizhen; ...

    2016-10-24

    Here we irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ~50 dpa, ~15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ~8 nm, ~1021 m-3 (CNA), and of ~3 nm, 1023 m-3 (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces inmore » all alloys survived ~50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Finally, among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.« less

  12. Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

    NASA Astrophysics Data System (ADS)

    Parish, C. M.; Unocic, K. A.; Tan, L.; Zinkle, S. J.; Kondo, S.; Snead, L. L.; Hoelzer, D. T.; Katoh, Y.

    2017-01-01

    We irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ∼50 dpa, ∼15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ∼8 nm, ∼1021 m-3 (CNA), and of ∼3 nm, 1023 m-3 (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces in all alloys survived ∼50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.

  13. Helium sequestration at nanoparticle-matrix interfaces in helium + heavy ion irradiated nanostructured ferritic alloys

    SciTech Connect

    Parish, Chad M.; Unocic, Kinga A.; Tan, Lizhen; Zinkle, S. J.; Kondo, Sosuke; Snead, Lance Lewis; Hoelzer, David T.; Katoh, Yutai

    2016-10-24

    Here we irradiated four ferritic alloys with energetic Fe and He ions: one castable nanostructured alloy (CNA) containing Ti-W-Ta-carbides, and three nanostructured ferritic alloys (NFAs). The NFAs were: 9Cr containing Y-Ti-O nanoclusters, and two Fe-12Cr-5Al NFAs containing Y-Zr-O or Y-Hf-O clusters. All four were subjected to simultaneous dual-beam Fe + He ion implantation (650 °C, ~50 dpa, ~15 appm He/dpa), simulating fusion-reactor conditions. Examination using scanning/transmission electron microscopy (STEM) revealed high-number-density helium bubbles of ~8 nm, ~1021 m-3 (CNA), and of ~3 nm, 1023 m-3 (NFAs). STEM combined with multivariate statistical analysis data mining suggests that the precipitate-matrix interfaces in all alloys survived ~50 dpa at 650 °C and serve as effective helium trapping sites. All alloys appear viable structural material candidates for fusion or advanced fission energy systems. Finally, among these developmental alloys the NFAs appear to sequester the helium into smaller bubbles and away from the grain boundaries more effectively than the early-generation CNA.

  14. Novel Methods of Lipidic Nanoparticle Preparation and Drug Loading

    NASA Astrophysics Data System (ADS)

    Maitani, Y.

    2013-09-01

    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.

  15. Preparation of sub-100-nm beta-lactoglobulin (BLG) nanoparticles.

    PubMed

    Ko, Sanghoon; Gunasekaran, Sundaram

    2006-12-01

    Sub-100-nm nanoparticles were prepared from beta-lactoglobulin (BLG) with a narrow size distribution by a desolvation method using glutaraldehyde for cross-linking. With pre-heating of the BLG solution to 60 degrees C and subsequent pH readjustment to 9.0, nanoparticles of 59 +/- 5 nm were obtained with improved uniformity. Bovine serum albumin (BSA) nanoparticles, prepared under similar conditions for comparison, were larger and less uniform. The half-width of 80% particle distribution was used to compare the uniformity of particle size distribution. The stability of the nanoparticles was investigated by degradation tests at neutral and acidic pHs with and without proteolytic enzymes, trypsin and pepsin. The degradation time, determined by a graphical approach, was used to compare the relative stabilities of BLG and BSA nanoparticles. The particles of BLG were more stable than those of BSA in acidic and neutral media with and without added enzymes.

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

    NASA Astrophysics Data System (ADS)

    Pervaiz, Erum; Gul, I. H.

    2012-11-01

    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 Ω-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.

  17. Zero-valent iron nanoparticles preparation

    SciTech Connect

    Oropeza, S.; Corea, M.; Gómez-Yáñez, C.; Cruz-Rivera, J.J.; Navarro-Clemente, M.E.

    2012-06-15

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

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

    SciTech Connect

    Kalogirou, O. Aristotle Univ., Thessaloniki )

    1993-02-01

    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.

  19. Structural and magnetic properties of nickel-zinc ferrite nanocrystalline magnetic particles prepared by microwave combustion method

    NASA Astrophysics Data System (ADS)

    Parmar, H.; Upadhyay, R. V.; Rayaprol, S.; Siruguri, V.

    2014-12-01

    Magnetic, nano-crystalline samples of zinc substituted nickel ferrite, (ZnxNi1-xFe2O4 for x = 0.0-0.9 in step of 0.2), are synthesized using microwave combustion synthesis technique. The structural properties of Ni-Zn are determined using X-ray powder diffraction, transmission electron microscopy; Fourier transforms infrared spectroscopy and neutron diffraction techniques. Average crystalline size obtained from X-ray diffraction and neutron diffraction is in the range of 30-60 nm. The cation distribution obtained from X-ray diffraction and neutron diffraction show that Zn occupies only tetrahedral A-site in the spinel lattice. The values of magnetic moment derived from magnetization measurements and neutron diffraction agrees nearly 97 % to that of bulk at 300 K. This methodology can be used to prepare large quantities (about 10 g) of sample at one time using kitchen microwave oven working at 1,200 W power.

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

    PubMed

    Singh, Charanjit; Goyal, Ankita; Singhal, Sonal

    2014-07-21

    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 m(2) 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 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 NiFe₂O₄ nanoparticles as catalyst.

  1. Antifungal activity of gold nanoparticles prepared by solvothermal method

    SciTech Connect

    Ahmad, Tokeer; Wani, Irshad A.; Lone, Irfan H.; Ganguly, Aparna; Manzoor, Nikhat; Ahmad, Aijaz; Ahmed, Jahangeer; Al-Shihri, Ayed S.

    2013-01-15

    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.

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

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Huang, Ying; Wang, Qiufen

    2012-09-01

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

  3. Effect of chromium substitution on the dielectric properties of mixed Ni-Zn ferrite prepared by WOWS sol–gel technique

    SciTech Connect

    Ashtar, M.; Munir, A.; Anis-ur-Rehman, M.; Maqsood, A.

    2016-07-15

    Graphical abstract: Variation of AC conductivity (σ{sub AC}) as a function of natural log of angular frequency (lnω) for Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2-x}Cr{sub x}O{sub 4} nanoferrites at room temperature. - Highlights: • Cr doped mixed Ni-Zn ferrites were successfully synthesized by a newly developed WOWS sol gel technique. • The specific surface area and specific surface area to volume ratio increased with decrease in particle size. • The resonance peaks appeared in dielectric loss graphs, shifting towards low frequency with the increase in Cr concentration. • The prepared samples have the lowest values of the dielectric constant. • The dielectric constant were observed to be inversely proportional to square root of the AC resistivity. - Abstract: Cr{sup +3} doped Ni-Zn nanoferrite samples with composition Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2-x}Cr{sub x}O{sub 4}(x = 0.1, 0.2, 0.3, 0.4) were synthesized With Out Water and Surfactant (WOWS) sol-gel technique. The structural, morphological and dielectric properties of the samples were investigated. The lattice constant, crystallite size, theoretical density and porosity of each sample were obtained from X-ray diffraction (XRD) data. The specific surface area and specific surface area to volume ratio increased with the decrease in the size of Cr{sup +3} doped Ni-Zn ferrite nanoparticles, as the concentration of Cr{sup +3} increased. The SEM analysis revealed that the particles were of nano size and of spherical shape. The dielectric parameters such as dielectric constant (ε′) and dielectric loss (tanδ) of all the samples as a function of frequency at room temperature were measured. The AC conductivity (σ{sub AC}) was determined from the dielectric parameters, which showed increasing trend with the rise in frequency.

  4. Superparamagnetic Particle Size Limit of Mn-Zn Ferrite Nanoparticles Synthesised Through Aqueous Method

    NASA Astrophysics Data System (ADS)

    Joseyphus, R. Justin; Narayanasamy, A.; Jeyadevan, B.; Shinoda, K.; Tohji, K.

    2006-05-01

    Mn0.67Zn0.33Fe2O4 nanoparticles with size ranging from 20 to 80 nm have been synthesized using the modified oxidation method. The Curie temperatures for all the samples are found to be within 630 ± 5 K suggesting that there is no size-dependent cation distribution. Mössbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K.

  5. Preparation and bactericide activity of gallic acid stabilized gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Moreno-Álvarez, S. A.; Martínez-Castañón, G. A.; Niño-Martínez, N.; Reyes-Macías, J. F.; Patiño-Marín, N.; Loyola-Rodríguez, J. P.; Ruiz, Facundo

    2010-10-01

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using X-ray diffraction, transmission electron microscopy, dynamic light scattering, and UV-Vis spectroscopy. Samples were identified as elemental gold and present spherical morphology, a narrow size distribution and good stabilization according to TEM and DLS results. The antibacterial activity of this gallic acid stabilized gold nanoparticles against S. mutans (the etiologic agent of dental caries) was assessed using a microdilution method obtaining a minimum inhibitory concentration of 12.31, 12.31, and 49.25 μg/mL for 13.7, 39.4, and 76.7 nm gold nanoparticles, respectively. The antibacterial assay showed that gold nanoparticles prepared in this work present a bactericide activity by a synergistic action with gallic acid. The MIC found for this nanoparticles are much lower than those reported for mixtures of gold nanoparticles and antibiotics.

  6. 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.

  7. Experimental observations of field-dependent activation of core and surface spins in Ni-ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Ceylan, A.; Hasanain, S. K.; Shah, S. Ismat

    2008-05-01

    The magnetic behavior of Ni-ferrite (NiFe2O4) nanoparticles synthesized in a solid state reaction process has been investigated. The cooling field, HCF, dependence of magnetization in a wide range of temperatures, from 5 to 300 K, has been examined for low and high field regimes. It has been observed that there is a transition region, ~3-4 T, between different mechanisms that controls the magnetization. At low fields, <3 T, classical blocking-unblocking of small particles governs the magnetization whereas spin-glass like behavior prevails at high fields, >4 T, starting below a well defined freezing temperature of 50 K. The HCF dependence of magnetic viscosity has shown that there is a significant jump in the relaxation rate of the particles around 4 T which appears as the boundary region for the temperature-dependent magnetization as well. These observations are interpreted as indicating that below the spin freezing temperature there is a boundary field (~4 T) where the strongly pinned surface spins are enabled to be thermally activated while below this field only core spins participate in the magnetic relaxation.

  8. Magnetic study of Mg 0.95Mn 0.05Fe 2O 4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Sharma, S. K.; Kumar, Ravi; Kumar, Shalendra; Siva Kumar, V. V.; Knobel, M.; Reddy, V. R.; Banerjee, A.; Singh, M.

    2007-01-01

    The magnetic properties of Mg 0.95Mn 0.05Fe 2O 4 ferrite samples with an average particle size of ˜6.0±0.6 nm have been studied using X-ray diffraction, Mössbauer spectroscopy, dc magnetization and frequency dependent real χ'(T) and imaginary χ″(T) parts of ac susceptibility measurements. A magnetic transition to an ordered state is observed at about 195 K from Mössbauer measurements. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization have been recorded at low field and show the typical behavior of a small particle system. The ZFC curve displays a broad maximum at T=195±5 K, a temperature which depends upon the distribution of particle volumes in the sample. The FC curve was nearly flat below T, as compared with monotonically increasing characteristics of non-interacting superparamagnetic systems indicating the existence of strong interactions among the nanoparticles. A frequency-dependent peak observed in χ'(T) is well described by Vogel-Fulcher law, yielding a relaxation time τ0=5.8×10-12 s and an interaction parameter T0=195±3 K. Such values show the strong interactions and rule out the possibility of spin-glass (SG) features among the nanoparticle system. On the other hand fitting with the Néel-Brown model and the power law yields an unphysical large value of τ0 (˜6×10 -69 and 1.2×10 -22 s respectively).

  9. Preparation of nanoferrites and their applications.

    PubMed

    Hazra, S; Ghosh, N N

    2014-02-01

    Ferrites have a plethora of applications in the myriad fields of technology. Ferrites are widely used in conventional electronic, electrical, and magnetic devices. For the past two decades, since the discovery of the superparamagnetic nature of nanostructured ferrites, their applications in biotechnology and biomedical sciences as well as in advanced electronics and microwave devices have gained immense attention. In this review, the historical development of ferrite science and technology, and the synthesis methods for ferrite nanoparticle preparation and their applications have been discussed. Various synthetic methods with typical examples, their advantages as well as limitations have been discussed in details. Traditional industrial applications of various ferrites have also been discussed citing relevant patents. Recent developments on nanoferrite research in terms of synthetic methods as well as advanced applications have been discussed elaborately.

  10. Structural and electrical properties of Cu doped NiFe2O4 nanoparticles prepared through modified citrate gel method

    NASA Astrophysics Data System (ADS)

    Batoo, Khalid Mujasam

    2011-12-01

    Nanoparticles of polycrystalline NiFe2-xCuxO4 (0.0≤x≤0.05) ferrites were prepared through the modified citrate-gel method. The samples were obtained as dried gel after the successful chemical reaction of their respective metal nitrate solutions in the midst of citric acid as catalyst. X-ray diffraction (XRD) and selective area electron diffraction (SAED) confirmed the single phase nature of all the samples with an average particle size of 19.8 (±1). Fourier transformation infrared spectroscopy (FTIR) shows the presence of two broad vibrational bands between 400 and 1000 cm-1 corresponding to the tetrahedral and the octahedral sites. The variation of dielectric properties (ɛ‧, ɛ″, tan δ) and ac conductivity (σac), with frequency reveals that the dispersion is due to the Maxwell-Wagner type of interfacial polarization in general and due to hopping of charges between Fe+2 and Fe+3 as well as between Ni+2 and Ni+3 ions at B-sites. The complex impedance spectroscopy has been used to study the effect of grain and grain boundary on the electrical properties of all the ferrite nanoparticles.

  11. Preparation and evaluations in vitro of oxaliplatin polylactic acid nanoparticles.

    PubMed

    Cui, Zhaoyuan; Sun, Yong; Liu, Xiaohong; Ju, Fang; Chen, Qian; Gao, Wen; Wei, Haitian

    2013-08-01

    The oxaliplatin nanoparticles were prepared with polylactic acid matrix, orthogonal test was applied to optimize the prescriptions, and the qualities of oxaliplatin nanoparticles were characterized by the shape, particle size, encapsulation efficiency (EE), and drug loading (DL). Oxaliplatin nanoparticle was prepared by solution replacement method. The formation of 0.25% Tween80, DMF-water 1:8 (v/v), oxaliplatin-polylactic acid 1:5 (w/w), and 20 mg/ml polylactic acid showed the suitable EE (17.4 ± 0.47%), DL (3.52 ± 0.07%). We observed the shape of oxaliplatin nanoparticles through SEM. The average size of the particles was 120.5 ± 8.7 nm, which was detected by N5 submicron particle size analyzer.

  12. Metal Nanoparticles Preparation In Supercritical Carbon Dioxide Solutions

    SciTech Connect

    Harry W. Rollins

    2004-04-01

    The novel optical, electronic, and/or magnetic properties of metal and semiconductor nanoparticles have resulted in extensive research on new methods for their preparation. An ideal preparation method would allow the particle size, size distribution, crystallinity, and particle shape to be easily controlled, and would be applicable to a wide variety of material systems. Numerous preparation methods have been reported, each with its inherent advantages and disadvantages; however, an ideal method has yet to emerge. The most widely applied methods for nanoparticle preparation include the sonochemical reduction of organometallic reagents,(1&2) the solvothermal method of Alivisatos,(3) reactions in microemulsions,(4-6) the polyol method (reduction by alcohols),(7-9) and the use of polymer and solgel materials as hosts.(10-13) In addition to these methods, there are a variety of methods that take advantage of the unique properties of a supercritical fluid.(14&15) Through simple variations of temperature and pressure, the properties of a supercritical fluid can be continuously tuned from gas-like to liquid-like without undergoing a phase change. Nanoparticle preparation methods that utilize supercritical fluids are briefly reviewed below using the following categories: Rapid Expansion of Supercritical Solutions (RESS), Reactive Supercritical Fluid Processing, and Supercritical Fluid Microemulsions. Because of its easily accessible critical temperature and pressure and environmentally benign nature, carbon dioxide is the most widely used supercritical solvent. Supercritical CO2 is unfortunately a poor solvent for many polar or ionic species, which has impeded its use in the preparation of metal and semiconductor nanoparticles. We have developed a reactive supercritical fluid processing method using supercritical carbon dioxide for the preparation of metal and metal sulfide particles and used it to prepare narrowly distributed nanoparticles of silver (Ag) and silver sulfide

  13. The impact of silica encapsulated cobalt zinc ferrite nanoparticles on DNA, lipids and proteins of rat bone marrow mesenchymal stem cells.

    PubMed

    Novotna, Bozena; Turnovcova, Karolina; Veverka, Pavel; Rössner, Pavel; Bagryantseva, Yana; Herynek, Vit; Zvatora, Pavel; Vosmanska, Magda; Klementova, Mariana; Sykova, Eva; Jendelova, Pavla

    2016-08-01

    Nanomaterials are currently the subject of intense research due to their wide variety of potential applications in the biomedical, optical and electronic fields. We prepared and tested cobalt zinc ferrite nanoparticles (Co0.5Zn0.5Fe2O4+γ [CZF-NPs]) encapsulated by amorphous silica in order to find a safe contrast agent and magnetic label for tracking transplanted cells within an organism using magnetic resonance imaging (MRI). Rat mesenchymal stem cells (rMSCs) were labeled for 48 h with a low, medium or high dose of CZF-NPs (0.05; 0.11 or 0.55 mM); silica NPs (Si-NPs; 0.11 mM) served as a positive control. The internalization of NPs into cells was verified by transmission electron microscopy. Biological effects were analyzed at the end of exposure and after an additional 72 h of cell growth without NPs. Compared to untreated cells, Annexin V/Propidium Iodide labeling revealed no significant cytotoxicity for any group of treated cells and only a high dose of CZF-NPs slowed down cell proliferation and induced DNA damage, manifested as a significant increase of DNA-strand breaks and oxidized DNA bases. This was accompanied by high concentrations of 15-F2t-isoprostane and carbonyl groups, demonstrating oxidative injury to lipids and proteins, respectively. No harmful effects were detected in cells exposed to the low dose of CZF-NPs. Nevertheless, the labeled cells still exhibited an adequate relaxation rate for MRI in repeated experiments and ICP-MS confirmed sufficient magnetic label concentrations inside the cells. The results suggest that the silica-coated CZF-NPs, when applied at a non-toxic dose, represent a promising contrast agent for cell labeling.

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

    PubMed

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

    2013-02-01

    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.

  15. [Preparation of scopolamine hydrobromide nanoparticles-in-microsphere system].

    PubMed

    Lü, Wei-ling; Hu, Jin-hong; Zhu, Quan-gang; Li, Feng-qian

    2010-07-01

    This study is to prepare scopolamine hydrobromide nanoparticles-in-microsphere system (SH-NiMS) and evaluate its drug release characteristics in vitro. SH nanoparticles were prepared by ionic crosslinking method with tripolyphosphate (TPP) as crosslinker and chitosan as carrier. Orthogonal design was used to optimize the formulation of SH nanoparticles, which took the property of encapsulation efficiency and drug loading as evaluation parameters. With HPMC as carrier, adjusted the parameters of spray drying technique and sprayed the SH nanoparticles in microspheres encaposulated by HPMC was formed and which is called nanoparticles-in-microsphere system (NiMS). SH-NiMS appearances were observed by SEM, structure was obsearved by FT-IR and the release characteristics in vitro were evaluated. The optimized formulation of SH nanoparticles was TPP/CS 1:3 (w/w), HPMC 0.3%, SH 0.2%. The solution peristaltic speed of the spray drying technique was adjusted to 15%, and the temperature of inlet was 110 degrees C. The encapsulation product yeild, drug loading and particle sizes of SH-NiMS were 94.2%, 20.4%, and 1256.5 nm, respectively. The appearances and the structure of SH-NiMS were good. The preparation method of SH-NiMS is stable and reliable to use, which provide a new way to develop new dosage form.

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

    PubMed

    Shi, Wenbing; Wang, Hui; Huang, Yuming

    2011-01-01

    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.

  17. Preparation of Chitosan Nanoparticles: A Study of Influencing Factors

    NASA Astrophysics Data System (ADS)

    Thakur, Anupama; Taranjit

    2011-12-01

    Chitosan (CS), a cationic polysaccharide, offers great advantages for ionic interactions with negatively charged species such as sodium tripolyphosphate (STPP) leading to the formation of biocompatible crosslinked chitosan nanoparticles In the present work, an attempt has been made to systematically study the following factors influencing the ionotropic gelation of chitosan with STPP to produce CS nanoparticles: effect of pH of solution, CS concentration, STPP concentration and CS/STPP ratio. The results show that with the increase in CS concentration, the yield of the nanoparticle decreases whereas size increases. The mean size of the prepared nanoparticles varied between 120 to 720 nm and zeta potential between +14 mV to +53 mV . Nanoparticle size and yield was found to be strongly dependent on solution pH. Nanoparticle size decreased with increase in solution pH from 4 to 5 and yield was found to be maximum at pH = 5. With increase in STPP concentration, the size and yield of the nanoparticle increased. The potential of CS nanoparticles to trap amoxicillin trihydrate, taken as the model drug, was also studied. The maximum drug loading capacity was found to be 35% at a solution pH = 5 for 0.2% CS and 0.086% STPP.

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

    SciTech Connect

    Shen, Yu; Wu, Yanbo; Xu, Hongfeng; Fu, Jie; Li, Xinyong; Zhao, Qidong; Hou, Yang

    2013-10-15

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  20. Preparation, characterization and optimization of glipizide controlled release nanoparticles

    PubMed Central

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

    2014-01-01

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

  1. Ultradispersed Cobalt Ferrite Nanoparticles Assembled in Graphene Aerogel for Continuous Photo-Fenton Reaction and Enhanced Lithium Storage Performance

    NASA Astrophysics Data System (ADS)

    Qiu, Bocheng; Deng, Yuanxin; Du, Mengmeng; Xing, Mingyang; Zhang, Jinlong

    2016-07-01

    The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe3+/Fe2+ and utilization rate of H2O2 are significant factors in Photo-Fenton reaction. In this work, we reported three dimensional (3D) hierarchical cobalt ferrite/graphene aerogels (CoFe2O4/GAs) composites by the in situ growing CoFe2O4 crystal seeds on the graphene oxide (GO) followed by the hydrothermal process. The resulting CoFe2O4/GAs composites demonstrated 3D hierarchical pore structure with mesopores (14~18 nm), macropores (50~125 nm), and a remarkable surface area (177.8 m2 g‑1). These properties endowed this hybrid with the high and recyclable Photo-Fenton activity for methyl orange pollutant degradation. More importantly, the CoFe2O4/GAs composites can keep high Photo-Fenton activity in a wide pH. Besides, the CoFe2O4/GAs composites also exhibited excellent cyclic performance and good rate capability. The 3D framework can not only effectively prevent the volume expansion and aggregation of CoFe2O4 nanoparticles during the charge/discharge processes for Lithium-ion batteries (LIBs), but also shorten lithium ions and electron diffusion length in 3D pathways. These results indicated a broaden application prospect of 3D-graphene based hybrids in wastewater treatment and energy storage.

  2. Ultradispersed Cobalt Ferrite Nanoparticles Assembled in Graphene Aerogel for Continuous Photo-Fenton Reaction and Enhanced Lithium Storage Performance

    PubMed Central

    Qiu, Bocheng; Deng, Yuanxin; Du, Mengmeng; Xing, Mingyang; Zhang, Jinlong

    2016-01-01

    The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe3+/Fe2+ and utilization rate of H2O2 are significant factors in Photo-Fenton reaction. In this work, we reported three dimensional (3D) hierarchical cobalt ferrite/graphene aerogels (CoFe2O4/GAs) composites by the in situ growing CoFe2O4 crystal seeds on the graphene oxide (GO) followed by the hydrothermal process. The resulting CoFe2O4/GAs composites demonstrated 3D hierarchical pore structure with mesopores (14~18 nm), macropores (50~125 nm), and a remarkable surface area (177.8 m2 g−1). These properties endowed this hybrid with the high and recyclable Photo-Fenton activity for methyl orange pollutant degradation. More importantly, the CoFe2O4/GAs composites can keep high Photo-Fenton activity in a wide pH. Besides, the CoFe2O4/GAs composites also exhibited excellent cyclic performance and good rate capability. The 3D framework can not only effectively prevent the volume expansion and aggregation of CoFe2O4 nanoparticles during the charge/discharge processes for Lithium-ion batteries (LIBs), but also shorten lithium ions and electron diffusion length in 3D pathways. These results indicated a broaden application prospect of 3D-graphene based hybrids in wastewater treatment and energy storage. PMID:27373343

  3. Perpendicularly oriented barium ferrite thin films with low microwave loss, prepared by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Da-Ming, Chen; Yuan-Xun, Li; Li-Kun, Han; Chao, Long; Huai-Wu, Zhang

    2016-06-01

    Barium ferrite (BaM) thin films are deposited on platinum coated silicon wafers by pulsed laser deposition (PLD). The effects of deposition substrate temperature on the microstructure, magnetic and microwave properties of BaM thin films are investigated in detail. It is found that microstructure, magnetic and microwave properties of BaM thin film are very sensitive to deposition substrate temperature, and excellent BaM thin film is obtained when deposition temperature is 910 °C and oxygen pressure is 300 mTorr (1 Torr = 1.3332 × 102 Pa). X-ray diffraction patterns and atomic force microscopy images show that the best thin film has perpendicular orientation and hexagonal morphology, and the crystallographic alignment degree can be calculated to be 0.94. Hysteresis loops reveal that the squareness ratio (M r/M s) is as high as 0.93, the saturated magnetization is 4004 Gs (1 Gs = 104 T), and the anisotropy field is 16.5 kOe (1 Oe = 79.5775 A·m-1). Ferromagnetic resonance measurements reveal that the gyromagnetic ratio is 2.8 GHz/kOe, and the ferromagnetic resonance linewith is 108 Oe at 50 GHz, which means that this thin film has low microwave loss. These properties make the BaM thin films have potential applications in microwave devices. Project supported by the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (Grant No. KFJJ201506), the Scientific Research Starting Foundation of Hainan University (Grant No. kyqd1539), and the Natural Science Foundation of Hainan Province (Grant No. 20165187).

  4. Platinum adlayered ruthenium nanoparticles, method for preparing, and uses thereof

    DOEpatents

    Tong, YuYe; Du, Bingchen

    2015-08-11

    A superior, industrially scalable one-pot ethylene glycol-based wet chemistry method to prepare platinum-adlayered ruthenium nanoparticles has been developed that offers an exquisite control of the platinum packing density of the adlayers and effectively prevents sintering of the nanoparticles during the deposition process. The wet chemistry based method for the controlled deposition of submonolayer platinum is advantageous in terms of processing and maximizing the use of platinum and can, in principle, be scaled up straightforwardly to an industrial level. The reactivity of the Pt(31)-Ru sample was about 150% higher than that of the industrial benchmark PtRu (1:1) alloy sample but with 3.5 times less platinum loading. Using the Pt(31)-Ru nanoparticles would lower the electrode material cost compared to using the industrial benchmark alloy nanoparticles for direct methanol fuel cell applications.

  5. Preparation of mesoporous cadmium sulfide nanoparticles with moderate pore size

    SciTech Connect

    Han Zhaohui Zhu, Huaiyong; Shi, Jeffrey; Parkinson, Gordon; Lu, G.Q.

    2007-03-15

    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.

  6. Preparation and Characterization of Polymeric Nanoparticles: An Interdisciplinary Experiment

    ERIC Educational Resources Information Center

    Ramalho, Maria J.; Pereira, M. Carmo

    2016-01-01

    In this work, a laboratory experiment to introduce graduate students to nanotechnology is described. Students prepared poly(lactic-"co"-glycolic acid) (PLGA) nanoparticles using two different synthesis procedures, a single and a double emulsion-solvent evaporation method. The students also performed a physicochemical characterization of…

  7. Structural analysis of emerging ferrite: Doped nickel zinc ferrite

    SciTech Connect

    Kumar, Rajinder; Kumar, Hitanshu; Singh, Ragini Raj; Barman, P. B.

    2015-08-28

    Ni{sub 0.6-x}Zn{sub 0.4}Co{sub x}Fe{sub 2}O{sub 4} (x = 0, 0.033, 0.264) nanoparticles were synthesized by sol-gel method and annealed at 900°C. Structural properties of all prepared samples were examined with X-ray diffraction (XRD). The partial formation of hematite (α-Fe{sub 2}O{sub 3}) secondary phase with spinel phase cubic structure of undoped and cobalt doped nickel zinc ferrite was found by XRD peaks. The variation in crystallite size and other structural parameters with cobalt doping has been calculated for most prominent peak (113) of XRD and has been explained on the basis of cations ionic radii difference.

  8. Versatile theranostics agents designed by coating ferrite nanoparticles with biocompatible polymers

    NASA Astrophysics Data System (ADS)

    Zahraei, M.; Marciello, M.; Lazaro-Carrillo, A.; Villanueva, A.; Herranz, F.; Talelli, M.; Costo, R.; Monshi, A.; Shahbazi-Gahrouei, D.; Amirnasr, M.; Behdadfar, B.; Morales, M. P.

    2016-06-01

    Three biocompatible polymers, polyethylene glycol (PEG), dextran and chitosan, have been used in this work to control the colloidal stability of magnetic nanoparticles (14 ± 5 nm in diameter) and to vary the aggregation state in order to study their effect on relaxometric and heating properties. Two different coating strategies have been deeply developed; one based on the formation of an amide bond between citric acid coated nanoparticles (NPs) and amine groups present on the polymer surface and the other based on the NP encapsulation. Relaxometric properties revealed that proton relaxation rates strongly depend on the coating layer hydrophilicity and the aggregation state of the particles due to the presence of magnetic interactions. Thus, while PEG coating reduces particle aggregation by increasing inter-particle spacing leading to reduction of both T1 and T2 relaxation, dextran and chitosan lead to an increase mainly in T2 values due to the aggregation of particles in bigger clusters where they are in close contact. Dextran and chitosan coated NPs have also shown a remarkable heating effect during the application of an alternating magnetic field. They have proved to be potential candidates as theranostic agents for cancer diagnosis and treatment. Finally, cytotoxicity of PEG conjugated NPs, which seem to be ideal for intravenous administration because of their small hydrodynamic size, was investigated resulting in high cell viability even at 0.2 mg Fe ml-1 after 24 h of incubation. This suspension can be used as drug/biomolecule carrier for in vivo applications.

  9. Preparation and magnetic properties of Ba-Co2Z and Sr-Zn2Y ferrites

    NASA Astrophysics Data System (ADS)

    Chen, In-Gann; Hsu, Shu-Hau; Chang, Y. H.

    2000-05-01

    We have prepared Ba-Co2Z and Sr-Zn2Y ferrites by mixing SrCO3 (BaCO3), Co2O3 (ZnO), and Fe2O3 and calcinating in air and O2. The effects of sintering atmosphere (O2 and Ar) and sintering temperatures (1373-1573 K) on the structural, magnetic, and electrical properties have been measured. The Ba-Co2Z sample sintered at 1573 K under a flowing O2 exhibits superior dc electrical resistivity (˜108Ω-cm), high initial permeability (u'˜21), and low loss factor (F˜1.6×10-3) at 20 MHz. The related XRD and SEM/EDS analyses of these samples have also been studied to correlate these properties. These results indicate that significant modification of magnetic properties up to 20 MHz can be achieved with the addition of the quaternary component and proper control of the processing oxygen atmosphere.

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    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.

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

    PubMed

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

    2012-12-17

    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 α-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.

  12. Ligand-induced evolution of intrinsic fluorescence and catalytic activity from cobalt ferrite nanoparticles.

    PubMed

    Pal, Monalisa; Kundu, Anirban; Rakshit, Rupali; Mandal, Kalyan

    2015-06-08

    To develop CoFe(2)O(4) as magneto-fluorescent nanoparticles (NPs) for biomedical applications, it would be advantageous to identify any intrinsic fluorescence of this important magnetic material by simply adjusting the surface chemistry of the NPs themselves. Herein, we demonstrate that intrinsic multicolor fluorescence, covering the whole visible region, can be induced by facile functionalization of CoFe(2)O(4) NPs with Na-tartrate. Moreover, the functionalized CoFe(2)O(4) NPs also show unprecedented catalytic efficiency in the degradation of both biologically and environmentally harmful dyes, pioneering the potential application of these NPs in therapeutics and wastewater treatment. Detailed investigation through various spectroscopic tools unveils the story behind the emergence of this unique optical property of CoFe(2)O(4) NPs upon functionalization with tartrate ligands. We believe our developed multifunctional CoFe(2)O(4) NPs hold great promise for advanced biomedical and technological applications.

  13. Preparation of metallic nanoparticles by irradiation in starch aqueous solution

    SciTech Connect

    Nemţanu, Monica R. Braşoveanu, Mirela Iacob, Nicuşor

    2014-11-24

    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 ΔE{sub ab} (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle h{sup o} 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.

  14. Synthesis of magnetic cobalt ferrite nanoparticles with controlled morphology, monodispersity and composition: the influence of solvent, surfactant, reductant and synthetic conditions

    NASA Astrophysics Data System (ADS)

    Lu, Le T.; Dung, Ngo T.; Tung, Le D.; Thanh, Cao T.; Quy, Ong K.; Chuc, Nguyen V.; Maenosono, Shinya; Thanh, Nguyen T. K.

    2015-11-01

    In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(iii) and Co(ii) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications.In our present work, magnetic cobalt ferrite (CoFe2O4) nanoparticles have been successfully synthesised by thermal decomposition of Fe(iii) and Co(ii) acetylacetonate compounds in organic solvents in the presence of oleic acid (OA)/ oleylamine (OLA) as surfactants and 1,2-hexadecanediol (HDD) or octadecanol (OCD-ol) as an accelerating agent. As a result, CoFe2O4 nanoparticles of different shapes were tightly controlled in size (range of 4-30 nm) and monodispersity (standard deviation only at ca. 5%). Experimental parameters, such as reaction time, temperature, surfactant concentration, solvent, precursor ratio, and accelerating agent, in particular, the role of HDD, OCD-ol, and OA/OLA have been intensively investigated in detail to discover the best conditions for the synthesis of the above magnetic nanoparticles. The obtained nanoparticles have been successfully applied for producing oriented carbon nanotubes (CNTs), and they have potential to be used in biomedical applications. Electronic

  15. Ferrous sulfate based low temperature synthesis and magnetic properties of nickel ferrite nanostructures

    SciTech Connect

    Tejabhiram, Y.; Pradeep, R.; Helen, A.T.; Gopalakrishnan, C.; Ramasamy, C.

    2014-12-15

    Highlights: • Novel low temperature synthesis of nickel ferrite nanoparticles. • Comparison with two conventional synthesis techniques including hydrothermal method. • XRD results confirm the formation of crystalline nickel ferrites at 110 °C. • Superparamagnetic particles with applications in drug delivery and hyperthermia. • Magnetic properties superior to conventional methods found in new process. - Abstract: We report a simple, low temperature and surfactant free co-precipitation method for the preparation of nickel ferrite nanostructures using ferrous sulfate as the iron precursor. The products obtained from this method were compared for their physical properties with nickel ferrites produced through conventional co-precipitation and hydrothermal methods which used ferric nitrate as the iron precursor. X-ray diffraction analysis confirmed the synthesis of single phase inverse spinel nanocrystalline nickel ferrites at temperature as low as 110 °C in the low temperature method. Electron microscopy analysis on the samples revealed the formation of nearly spherical nanostructures in the size range of 20–30 nm which are comparable to other conventional methods. Vibrating sample magnetometer measurements showed the formation of superparamagnetic particles with high magnetic saturation 41.3 emu/g which corresponds well with conventional synthesis methods. The spontaneous synthesis of the nickel ferrite nanoparticles by the low temperature synthesis method was attributed to the presence of 0.808 kJ mol{sup −1} of excess Gibbs free energy due to ferrous sulfate precursor.

  16. The optical nonlinearity of gold nanoparticles prepared by bioreduction method

    NASA Astrophysics Data System (ADS)

    Balbuena Ortega, A.; Arroyo Carrasco, M. L.; Gayou, V. L.; Orduña Díaz, A.; Delgado Macuil, R.; Rojas López, Marlon

    2013-11-01

    Nonlinear optical and electronic properties of nanosized metal particles have drawn considerable attention because of their strong and size-dependent plasmon resonance absorption. In a metal nanoparticle system such as gold dispersed in a transparent matrix, an absorption peak due to surface plasmon resonance is usually observed in the visible spectral region. Metal nanoparticles are of special interest as nonlinear materials for optical switching and computing because of their relatively large third-order nonlinearity (χ3) and ultrafast response time. The purpose of this study was to analyze the nonlinear optical properties of biosynthesized gold nanoparticles. The samples were prepared by biosynthesis method using yeast extract as reducing agent and the nonlinear optical properties of the nanoparticles were investigated using a single beam Z-scan technique with a beam power of 20 mW and operated at wavelength of 514 nm. The reaction between metal ions and yeast extracts were monitored by UV-visible spectra of Au nanoparticles in aqueous solution with different pH (3-6). The surface plasmon peak position was shifted from 528 nm to 573 nm, according to of pH variation 4 to 6. The average particle size was calculated by the absorption peak position using the Fernig method, from 42 to 103 nm. The z-scan curves showed a negative nonlocal nonlinear refractive index with a magnitude dependent on the nanoparticle size.

  17. Superparamagnetic behavior of heat treated Mg0.5Zn0.5Fe2O4 ferrite nanoparticles studied by Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Singh, S. B.; Tirupanyam, B. V.; Meena, S. S.; Yusuf, S. M.; Prasad, S. A. V.; Krishna, K. S. Rama; Sastry, D. L.

    2016-05-01

    Nanoparticles of Mg0.5Zn0.5Fe2O4 ferrite have been synthesized by co-precipitation method. XRD and Mössbauer spectroscopic results of Mg0.5Zn0.5Fe2O4 annealed at 200 °C, 500 °C and 800 °C are reported. It was observed that the crystallite size increases and the lattice parameter decreases with increase in annealing temperature. The observed decrease in lattice strain supports the increase in crystallite size. The Mössbauer spectra of the samples annealed at 200 °C and 500 °C exhibits superparamagnetic doublets whereas the Mössbauer spectrum of the sample annealed at 800 °C exhibits paramagnetic doublet along with weak sextet of hyperfine interaction. The values of isomer shift resemble the presence of high spin iron ions. The studied ferrite nanoparticles are suitable for biomedical applications. The results are incorporated employing core-shell model and cation redistribution.

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

    SciTech Connect

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

    2013-02-05

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  20. Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

    PubMed Central

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

    2010-01-01

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

  1. Preparation and Characterization of Chitosan Nanoparticles for Zidovudine Nasal Delivery.

    PubMed

    Barbi, Mariana Da Silva; Carvalho, Flávia Chiva; Kiill, Charlene Priscila; Barud, Hernane Da Silva; Santagneli, Sílvia Helena; Ribeiro, Sidney José Lima; Gremião, Maria Palmira Daflon

    2015-01-01

    Zidovudine (AZT) is the antiretroviral drug most frequently used for the treatment of Acquired Immunodeficiency Syndrome. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. The nasal route is an option for enhanced therapeutic efficacy and to reduce the extent of the first-pass effect. In this article, AZT loaded chitosan nanoparticles were prepared by a modified ionotropic gelation method with sodium tripolyphosphate. The increase proportion of CS (NP1 10:01 (w/w)) promoted the formation of smaller nanoparticles (260 nm), while raising the proportion of TPP (NP2 5:1 w/w) increased the nanoparticles size (330 nm). The incorporation of AZT increased the nanoparticles size for both AZT-loaded nanoparticles AZT-loaded NP1 (406 nm) and AZT-loaded NP2 (425 nm). The incorporation of AZT into NP1 did not change the electrophoretic mobility, however, in AZT-loaded NP2 there was a significant increase. The positive surface of the nanoparticles is very important for the mucoadhesive properties due interaction with the sialic groups of the mucin. Nuclear resonance magnetic data showed that the higher concentration of chitosan in the nanoparticles favored the interaction of few phosphate units (pyrophosphate) by ionic interaction Scanning electron microscopy, revealed that the nanoparticles are nearly spherical shape with porous surface. The entrapment efficiency of AZT, was 17.58% ± 1.48 and 11.02% ± 2.05 for NP1 and NP2, respectively. The measurement of the mucoadhesion force using mucin discs and nasal tissue obtained values of NP1 = 2.12 and NP2 = 4.62. In vitro permeation study showed that the nanoparticles promoted an increase in the flux of the drug through the nasal mucosa. In view of these results, chitosan nanoparticles were found to be a promising approach for the incorporation of hydrophilic drugs and these results suggest that the CS-containing nanoparticles have great potential for nasal AZT

  2. Effect of Gd3+- Cr3+ ion substitution on the structural, electrical and magnetic properties of Ni - Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Anupama, M. K.; Rudraswamy, B.

    2016-09-01

    Gd3+ doped nickel zinc nanoceramics with general formula Ni0.4Zn0.6Cr0.5GdxFe1.5 - xO4 (where x=0.00, 0.02, 0.04, 0.06) were synthesized by solution combustion method using oxylyldehydrazine as a fuel. The obtained powder was sintered at 1000°C for 2h. The detailed structural, electrical and magnetic studies were carried out through X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), impedance spectroscopy and vibrating sample magnetometer (VSM). The XRD pattern of as prepared sample confirms the formation of single phase with cubic spinel structure. The average crystallite size was found to be 34 to 19 nm and decreases with increasing Gd3+ ion concentration. The IR spectra exhibited two expected absorption bands between 600 to 300 cm-1 corresponding to the stretching vibrations of tetrahedral (A) and octahedral (B) metal oxygen vibrations. The variation of room temperature real (ε') and imaginary (ε") part of dielectric permittivity as a function of frequency and composition have been studied in the frequency range from 40Hz to 10MHz. The real and imaginary dielectric permittivity decreases with increase in frequency as well as Gd3+ concentration, which is normal behaviour of ferrite material and results have been explained on the basis of Maxwell - Wagner's two layer model. The VSM results showed that the Gd3+ concentration had significant impact on the saturation magnetization and coercivity, x = 0.02 shows the highest value of dielectric constant and saturation magnetization, thus the material is becoming low loss dielectric and highly resistive and soft magnetic material due to Gd-Cr doping.

  3. Structural and multiferroic properties of barium substituted bismuth ferrite nanocrystallites prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Anju; Agarwal, Ashish; Aghamkar, Praveen; Lal, Bhajan

    2017-03-01

    Nanocrystalline Bi1-xBaxFeO3 (0≤x≤0.3) multiferroics were efficiently obtained by sol-gel method after sintering at 800 °C for one hour. The Ba substitution in BiFeO3 (BFO) strongly modifies its structural and multiferroic properties. XRD studies revealed the structural transition from distorted rhombohedral (R3c) to pseudo-cubic (Pm3m) crystal symmetry. The magnetization increases appreciably for x=0.1, which is due to spin canting of magnetic moments at the nanoparticle surfaces and decreases afterward. From the temperature dependent magnetization studies, it is found that magnetic transition temperature (TN) is 620 K for x=0 and 640 K for x=0.1. Besides, the maximum polarisation value decreases with increasing Ba content. SEM micrographs revealed the formation of cubic nanocrystallites with increased porosity on Ba substitution. FTIR analysis of the samples also supports the structural change towards increased crystal symmetry.

  4. Cytotoxicity of gold nanoparticles prepared by ultrasonic spray pyrolysis.

    PubMed

    Rudolf, R; Friedrich, B; Stopić, S; Anžel, I; Tomić, S; Čolić, M

    2012-01-01

    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 electron microscopy with a combination of energy dispersive X-ray analysis, were nontoxic for thymocytes, but reduced moderately the proliferative activity of L929 cells. The inhibitory effect of fraction 2, containing particles smaller in size than fraction 1, was stronger. Fraction 3, composed of Au and up to 3% Cu was noncytotoxic for thymocytes, but was cytotoxic for L929 cells. Fraction 4, composed of Au and Ag nanoparticles, and fraction 5, composed of Au together with Cu, Ni, Zn, Fe, and In were cytotoxic for both thymocytes and L929 cells. These results suggest that USP enables the synthesis of pure gold nanoparticles with controlled size, even from gold scrap. However, microstructural analyses and biocompatibility testing are necessary for their proper selection from more cytotoxic gold nanoparticles, contaminated with other elements of gold alloys.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

    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).

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

    PubMed Central

    2012-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    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.

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

    NASA Astrophysics Data System (ADS)

    Ranjith Kumar, E.; Jayaprakash, R.

    2014-10-01

    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 α-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 (έ) and dielectric loss (D) of the spinel MnxZn1-xFe2O4 nanoparticles was measured using impedance analyzer in the frequency range 100 kHz-5 MHz.

  9. Nanocrystalline spinel ferrite (MFe{sub 2}O{sub 4}, M = Ni, Co, Mn, Mg, Zn) powders prepared by a simple aloe vera plant-extracted solution hydrothermal route

    SciTech Connect

    Phumying, Santi; Labuayai, Sarawuth; Swatsitang, Ekaphan; Amornkitbamrung, Vittaya; Maensiri, Santi

    2013-06-01

    Graphical abstract: This figure shows the specific magnetization curves of the as-prepared MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders obtained from room temperature VSM measurement. These curves are typical for a soft magnetic material and indicate hysteresis ferromagnetism in the field ranges of ±500 Oe, ±1000 Oe, and ±2000 Oe for the CoFe{sub 2}O{sub 4}, MgFe{sub 2}O{sub 4} and MnFe{sub 2}O{sub 4} respectively, whereas the samples of NiFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} show a superparamagnetic behavior. Highlights: ► Nanocrystalline MFe{sub 2}O{sub 4} powders were synthesized by a novel hydrothermal method. ► Metal acetylacetonates and aloe vera plant-extracted solution are used. ► This biosynthetic route is very simple and provides high-yield oxide nanomaterials. ► XRD and TEM results indicate that the prepared samples have only spinel structure. ► The maximum M{sub s} of 68.9 emu/g at 10 kOe were observed for the samples of MnFe{sub 2}O{sub 4}. - Abstract: Nanocrystalline spinel ferrite MFe{sub 2}O{sub 4} (M = Ni, Co, Mn, Mg, Zn) powders were synthesized by a novel hydrothermal method using Fe(acac){sub 3}, M(acac){sub 3} (M = Ni, Co, Mn, Mg, Zn) and aloe vera plant extracted solution. The X-ray diffraction and selected-area electron diffraction results indicate that the synthesized nanocrystalline have only spinel structure without the presence of other phase impurities. The crystal structure and morphology of the spinel ferrite powders, as revealed by TEM, show that the NiFe{sub 2}O{sub 4} and CoFe{sub 2}O{sub 4} samples contain nanoparticles, whereas the MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples consist of many nanoplatelets and nanoparticles. Interestingly, the ZnFe{sub 2}O{sub 4} sample contains plate-like structure of networked nanocrystalline particles. Room temperature magnetization results show a ferromagnetic behavior of the CoFe{sub 2}O{sub 4}, MnFe{sub 2}O{sub 4} and MgFe{sub 2}O{sub 4} samples, whereas the

  10. Controlling of optical energy gap of Co-ferrite quantum dots in poly (methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    El-Sayed, H. M.; Agami, W. R.

    2015-07-01

    Different crystallite sizes of Co-ferrite nanoparticles were prepared and dispersed in the matrix of poly (methyl methacrylate) (PMMA) polymer. The effect of crystallite size on the structure and optical energy gap of Co-nanoferrite/PMMA composite has been studied. The optical energy gap of Co-ferrite was greatly affected by the crystallite size. This result was discussed in terms of the formation of electron-hole exciton using particle in a box model. The effective mass and the Bohr radius of the formed exciton have been calculated from the spectroscopic measurements.

  11. Magnetic and Structural Properties of Nanosized Magnesium Doped Zinc Ferrite Synthesized by Citrate Precursor Method

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; Bansal, Shweta Dikshu; Singh, Simranjit

    2011-12-01

    Nanoparticles of MgxZn1-xFe2O4 ferrite (where x = 0.2, 0.4, 0.5,) are synthesized via citrate precursor method and then all the samples are sintered at 600 °C for 1 hour. The prepared samples are characterized through XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), TEM (transmission electron microscope) and VSM (vibrating sample magnetometer). The M-H curves show evidence of a superparamagnetic (SPM) regime in the synthesized ferrites.

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

    DOEpatents

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

    2012-07-03

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

  13. 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)

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

    2014-08-01

    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.

  14. Zinc substituted ferrite nanoparticles with Zn0.9Fe2.1O4 formula used as heating agents for in vitro hyperthermia assay on glioma cells

    NASA Astrophysics Data System (ADS)

    Hanini, Amel; Lartigue, Lenaic; Gavard, Julie; Kacem, Kamel; Wilhelm, Claire; Gazeau, Florence; Chau, François; Ammar, Souad

    2016-10-01

    In this paper we investigate the ability of zinc rich ferrite nanoparticles to induce hyperthermia on cancer cells using an alternating magnetic field (AMF). First, we synthesized ferrites and then we analyzed their physico-chemical properties by transmission electron microscopy, X-ray diffraction and magnetic and magnetocalorimetric measurements. We found that the polyol-made magnetically diluted particles are of 11 nm in size. They are superparamagnetic at body temperature (310 K) with a low but non-negligible magnetization. Interestingly, as nano-ferrimagnets they exhibit a Curie temperature of 366 K, close to the therapeutic temperature range. Their effect on human healthy endothelial (HUVEC) and malignant glioma (U87-MG) cells was also evaluated using MTT viability assays. Incubated with the two cell lines, at doses ≤100 μg mL-1 and contact times ≤4 h, they exhibit a mild in vitro toxicity. In these same operating biological conditions and coupled to AMF (700 kHz and 34.4 Oe) for 1 h, they rapidly induce a net temperature increase. In the case of tumor cells it reaches 4 K, making the produced particles particularly promising for self-regulated magnetically-induced heating in local glioma therapy.

  15. Facile synthesis of cobalt ferrite nanotubes using bacterial nanocellulose as template.

    PubMed

    Menchaca-Nal, S; Londoño-Calderón, C L; Cerrutti, P; Foresti, M L; Pampillo, L; Bilovol, V; Candal, R; Martínez-García, R

    2016-02-10

    A facile method for the preparation of cobalt ferrite nanotubes by use of bacterial cellulose nanoribbons as a template is described. The proposed method relays on a simple coprecipitation operation, which is a technique extensively used for the synthesis of nanoparticles (either isolated or as aggregates) but not for the synthesis of nanotubes. The precursors employed in the synthesis are chlorides, and the procedure is carried out at low temperature (90 °C). By the method proposed a homogeneous distribution of cobalt ferrite nanotubes with an average diameter of 217 nm in the bacterial nanocellulose (BC) aerogel (3%) was obtained. The obtained nanotubes are formed by 26-102 nm cobalt ferrite clusters of cobalt ferrite nanoparticles with diameters in the 9-13 nm interval. The nanoparticles that form the nanotubes showed to have a certain crystalline disorder, which could be attributed in a greater extent to the small crystallite size, and, in a lesser extent, to microstrains existing in the crystalline lattice. The BC-templated-CoFe2O4 nanotubes exhibited magnetic behavior at room temperature. The magnetic properties showed to be influenced by a fraction of nanoparticles in superparamagnetic state.

  16. Preparation and applications of ZnSe nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

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

  17. Magnetic properties of iron nanoparticles prepared by exploding wire technique.

    PubMed

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

    2007-06-01

    Nanoparticles of iron were prepared in distilled water using very thin iron wires and sheets, by the electro-exploding wire technique. Transmission electron microscopy reveals the size of the nanoparticles to be in the range 10 to 50 nm. However, particles of different sizes can be segregated by using ultrahigh centrifuge. X-ray diffraction studies confirm the presence of the cubic phase of iron. These iron nanoparticles were found to exhibit fluorescence in the visible region in contrast to the normal bulk material. The room temperature hysteresis measurements upto a field of 1.0 tesla were performed on a suspension of iron particles in the solution as well as in the powders obtained by filtration. The hysteresis loops indicate that the particles are superparamagnetic in nature. The saturation magnetizations was approximately 60 emu/gm. As these iron particles are very sensitive to oxygen a coating of non-magnetic iron oxide tends to form around the particles giving it a core-shell structure. The core particle size is estimated theoretically from the magnetization measurements. Suspensions of iron nanoparticles in water have been proposed to be used as an effective decontaminant for ground water.

  18. Bioinspired preparation of alginate nanoparticles using microbubble bursting.

    PubMed

    Elsayed, Mohamed; Huang, Jie; Edirisinghe, Mohan

    2015-01-01

    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 200 nm 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.

  19. Nanoparticle preparation of Mefenamic acid by electrospray drying

    SciTech Connect

    Zolkepali, Nurul Karimah Bakar, Noor Fitrah Abu Anuar, Nornizar; Naim, M. Nazli; Bakar, Mohd Rushdi Abu

    2014-02-24

    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 (2.77–8.55μScm{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.

  20. Fluorescent monolayer protected gold nanoparticles - Preparation and structure elucidation

    NASA Astrophysics Data System (ADS)

    Angelova, P.; Kuchukova, N.; Dobrikov, G. M.; Timtcheva, I.; Kostova, K.; Petkova, I.; Vauthey, E.

    2011-05-01

    A novel N-substituted 4-methoxy-1,8-naphthalimide (NAFTA 8) especially designed for fluorescent labeling of gold nanoparticles has been synthesized. NAFTA 8 bears a long methylene chain at the imide N atom and has a terminal SH group, which enables its chemical binding to gold nanostructures. The longest wavelength absorption maximum of NAFTA 8 in chloroform is at 370 nm, the fluorescent maximum is at 430 nm and the fluorescent quantum yield is 0.95. The newly synthesized fluorophore is applied for functionalization of gold nanoparticles with diameter 1.5 ± 0.5 nm prepared through chemical reduction. The obtained Monolayer Protected Clusters are characterized by elemental analysis, TEM, XPS, FT-IR, absorption and fluorescence spectroscopy. The performed investigations provide evidence for the formation of chemical bond between the thiol ligand and the gold surface. They also show that the obtained metal/dielectric 3D structures are highly fluorescent.

  1. Structural and Dielectric Properties of Bismuth Doped Cobalt Nano Ferrites Prepared by Sol-Gel Auto Combustion Method

    NASA Astrophysics Data System (ADS)

    Routray, Krutika L.; Behera, Dhrubananda

    2017-02-01

    The present study is focused on the preparation of a series of Bismuth doped CoFe2O4 (CFO) nanoparticles and its structural and dielectric properties. The CFO particles having chemical composition CoBixFe2-xO4 (where x = 0.0, 0.1, 0.5) has been synthesized using sol-gel auto combustion method. Phase formation study of the prepared samples is carried out using X -ray diffraction (XRD) technique. It reveals single phase spinel structure having space group Fd3m. The two absorption bands v 1 and v 2 are observed in Fourier transform infrared spectroscopy (FTIR) spectra corresponding to the tetrahedral and octahedral sites, which show mark of spinel structure of the samples. Morphological study is carried out using Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopy (TEM) which revealed that the particle size obtained is around 40 nm to 120 nm. In addition, phase formation has been confirmed from the analysis of Raman spectra. Different types of conduction mechanism of the charge carriers have been analysed with DC resistivity and AC impedance measurement at room temperature. Results demonstrate the presence of dielectric relaxation, which is found to be of non-Debye type.

  2. X-ray diffraction studies on crystallite size evolution of CoFe 2O 4 nanoparticles prepared using mechanical alloying and sintering

    NASA Astrophysics Data System (ADS)

    Waje, Samaila Bawa; Hashim, Mansor; Yusoff, Wan Daud Wan; Abbas, Zulkifly

    2010-03-01

    Nanosized cobalt ferrite spinel particles have been prepared by using mechanically alloyed nanoparticles. The effects of various preparation parameters on the crystallite size of cobalt ferrite which includes milling time; ball-to powder weight ratio (BPR) and sintering temperature, were studied using X-ray diffractometer (XRD). Scherrer's equation was used to study the crystallite size evolution of the as-prepared materials. The results of the as-milled sample revealed that both milling time and BPR plays a role in determining the crystallite size of the milled powder. However, where sintering is involved, the sintering temperature results in grain growth, and thus plays a dominant role in determining the final crystallite size of the samples sintered at higher temperature (above 900 °C). From the vibrating-sample magnetometer (VSM) measurement it was observed that the coercivity of the as-milled samples without sintering is almost negligible, which is a type characteristic of superparamagnetic material. However, for the sintered samples, the saturation increases while coercivity decreases with increases sintering temperature.

  3. Sol-Gel-Prepared Nanoparticles of Mixed Praseodymium Cobaltites-Ferrites.

    PubMed

    Pekinchak, Olga; Vasylechko, Leonid; Lutsyuk, Iryna; Vakhula, Yaroslav; Prots, Yuri; Carrillo-Cabrera, Wilder

    2016-12-01

    Two series of nanocrystalline powders of PrCo1 - x Fe x O3 (x = 0.1, 0.3, 0.5, 0.7 and 0.9) of high purity were obtained by sol-gel citrate method at 700 and 800 °C. The formation of continuous solid solution with an orthorhombic perovskite structure (sp. group Pbnm) was observed. A peculiarity of the PrCo1 - x Fe x O3 solid solution is the lattice parameter crossovers, which occurred at certain compositions and revealed in the pseudo-tetragonal or pseudo-cubic metric. An average crystallite size of the PrCo1 - x Fe x O3 samples estimated from the analysis of the angular dependence of the X-ray diffraction (XRD) line broadening varies between 30 and 155 nm, depending on the composition and synthesis temperature.

  4. Aqueous Solution Preparation, Structure, and Magnetic Properties of Nano-Granular ZnxFe3−xO4 Ferrite Films

    PubMed Central

    2010-01-01

    This paper reports a simple and novel process for preparing nano-granular ZnxFe3−xO4 ferrite films (0 ≤ x ≤ 0.99) on Ag-coated glass substrates in DMAB-Fe(NO3)3-Zn(NO3)2 solutions. The deposition process may be applied in preparing other cations-doped spinel ferrite films. The Zn content x in the ZnxFe3−xO4 films depends linearly on the Zn2+ ion concentration ranging from 0.0 to 1.0 mM in the aqueous solutions. With x increasing from 0 to 0.99, the lattice constant increases from 0.8399 to 0.8464 nm; and the microstructure of the films changes from the non-uniform nano-granules to the fine and uniform nano-granules of 50–60 nm in size. The saturation magnetization of the films first increases from 75 emu/g to the maximum 108 emu/g with x increasing from 0 to 0.33 and then decreases monotonously to 5 emu/g with x increasing from 0.33 to 0.99. Meanwhile, the coercive force decreases monotonously from 116 to 13 Oe. PMID:20730079

  5. Large scale purification of RNA nanoparticles by preparative ultracentrifugation.

    PubMed

    Jasinski, Daniel L; Schwartz, Chad T; Haque, Farzin; Guo, Peixuan

    2015-01-01

    Purification of large quantities of supramolecular RNA complexes is of paramount importance due to the large quantities of RNA needed and the purity requirements for in vitro and in vivo assays. Purification is generally carried out by liquid chromatography (HPLC), polyacrylamide gel electrophoresis (PAGE), or agarose gel electrophoresis (AGE). Here, we describe an efficient method for the large-scale purification of RNA prepared by in vitro transcription using T7 RNA polymerase by cesium chloride (CsCl) equilibrium density gradient ultracentrifugation and the large-scale purification of RNA nanoparticles by sucrose gradient rate-zonal ultracentrifugation or cushioned sucrose gradient rate-zonal ultracentrifugation.

  6. Preparation of Aromatic Polycarbonate Nanoparticles using Supercritical Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Young; Song, Cheong-Hun; Kim, Joong-In; Kim, Jung-Hyun

    2002-04-01

    A novel synthetic process for producing aromatic polycarbonate (PC) nanoparticles using supercritical CO2 was developed. The objective of the present research work was to synthesize high molecular weight PC nanoparticles using transesterification between bisphenol-A (BPA) and diphenyl carbonate (DPC) in supercritical CO2 which is an excellent plasticizing agent and a good solvent for phenol, a by-product of the reaction. Poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) tri-block copolymer with CO2-phobic anchor and CO2-philic tail group was used as a stabilizer for the preparation of stable dispersions of BPA-DPC mixture in a CO2 continuous phase. As the reaction was proceeding, phenol formed from the reaction was dissolved and diffused into supercritical CO2 phase. The PC nanoparticles were isolated by simple venting of the supercritical CO2 from the reactor. Spherical morphology of PC particles was confirmed by scanning electron microscopy. Particle size and morphology of PC particles were modified upon variation of the process conditions. The resulting PC particles with a nano-size of 30-140 nm have a high molecular weight ( M w) of 3.1×105 (g/mol).

  7. Preparation of nanocrystalline NiZnCu ferrite particles by sol-gel method and their magnetic properties

    NASA Astrophysics Data System (ADS)

    Yan, Shifeng; Geng, Jianxin; Yin, Li; Zhou, Enle

    2004-06-01

    Polyvinyl alcohol (PVA) was first used as chelating agent and metal nitrates as precursor of ferrite in the fabrication of nanocrystalline Ni 0.65Zn 0.35Cu 0.1Fe 1.9O 4 particles by the sol-gel method. The thermal decomposition process of dried gel was studied by thermogravimetry (TG), differential thermal analysis (DTA) and infrared spectra (IR). The structural and magnetic properties of resultant particles were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy. The dependence of the decomposition of dried gel, the formation of spinel structured NiZnCu ferrite, the sizes of annealed particles, the saturation magnetization and coercivity of annealed particles on annealing temperature is presented.

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 μm, and the inner dimension of the alloy is in the range of 15-40 μm. By coating Ni-Zn-ferrites, the electrical resistivity is increased. The composite exhibits not only good soft magnetic properties but also good mechanical strength.

  9. Enhanced magneto-optical Kerr effect in rare earth substituted nanostructured cobalt ferrite thin film prepared by sol-gel method

    NASA Astrophysics Data System (ADS)

    Avazpour, L.; Toroghinejad, M. R.; Shokrollahi, H.

    2016-11-01

    A series of rare-earth (RE)-doped nanocrystalline Cox RE(1-x) Fe2O4 (x = 0, 0.1, 0.2 and RE: Nd, Eu) thin films were prepared on silicon substrates by a sol-gel process, and the influences of different RE3+ ions on the microstructure, magnetism and polar magneto-optical Kerr effect of the deposited films were investigated. Also this research presents the optimization process of cobalt ferrite thin films deposited via spin coating, by studying their structural and morphological properties at different thicknesses (200, 350 nm) and various heat treatment temperatures 300-850 °C. Nanoparticulate polycrystalline thin film were formed with heat treatment above 400 °C but proper magnetic properties due to well crystallization of the film were achieved at about 650 °C. AFM results indicated that the deposited thin films were crack-free exhibiting a dense nanogranular structure. The root-mean square (RMS) roughness of the thin films was in the range of 0.2-3.2 nm. The results revealed that both of the magnetism and magneto optical Kerr (MOKE) spectra of Cox RE(1-x) Fe2O4 films could be mediated by doping with various RE ions. The Curie temperature of substituted samples was lower than pristine cobalt ferrite thin films. In MOKE spectra both dominant peaks were blue shifted with addition of RE ions. For low concentration dopant the inter-valence charge transfer related rotation was enhanced and for higher concentration dopant the crystal field rotation peak was enhanced. The MOKE enhancement for Eu3+ substituted samples was more than Nd3+ doped cobalt ferrite films. The enhanced MOKEs in nanocrystalline thin films might promise their applications for magneto-optical sensors in adopted wavelengths.

  10. Synthesis and Characterization of Sol-Gel Prepared Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Ahlawat, Dharamvir Singh; Kumari, Rekha; Rachna; Yadav, Indu

    2014-03-01

    Silver nanoparticles (SNPs) have been successfully prepared using sol-gel method by annealing the sample at 550°C for 30 min. The SNPs were not confirmed by X-ray diffraction (XRD) analysis when the annealing temperature was considered at 450°C. They were also not confirmed without calcination of the sample. The physical mechanism of silver clusters formation in the densified silica matrix with respect to thermal treatment has been understood. The presence of silver metal in the silica matrix was confirmed by XRD analysis and TEM image of the samples. The average size of nanoparticles dispersed in silica matrix was determined as 10.2 nm by the XRD technique. The synthesized nanocomposites were also characterized by UV-Visible spectroscopy with a peak in the absorption spectra at around 375 nm. The distribution of particle size has been reported here in the range from 8 nm to 25 nm by TEM observations of the sample prepared at 550°C. The spherically smaller size (≈10 nm) SNPs have reported the surface plasmons resonance (SPR) peak less than or near to 400 nm due to blue-shifting and effect of local refractive index. Without annealing the silica samples the absorption spectra does not show any peak around 375 nm. The FTIR spectroscopy of the three types of samples prepared at different temperatures (room temperature, 450°C and 550°C) has also been reported. This spectra have provided the identification of different chemical groups in the prepared samples. It has been predicted that the size of SNPs by XRD, UV-Visible and TEM results have agreed well with each other. It may be concluded that formation of SNPs is a function of annealing temperature.

  11. Ultrasonic treatment of glassy carbon for nanoparticle preparation.

    PubMed

    Levêque, Jean-Marc; Duclaux, Laurent; Rouzaud, Jean-Noël; Reinert, Laurence; Komatsu, Naoki; Desforges, Alexandre; Afreen, Sadia; Sivakumar, Manickam; Kimura, Takahide

    2017-03-01

    Glassy carbon particles (millimetric or micrometric sizes) dispersions in water were treated by ultrasound at 20kHz, either in a cylindrical reactor, or in a "Rosette" type reactor, for various time lengths ranging from 3h to 10h. Further separations sedimentation allowed obtaining few nanoparticles of glassy carbon in the supernatant (diameter <200nm). Thought the yield of nanoparticle increased together with the sonication time at high power, it tended to be nil after sonication in the cylindrical reactor. The sonication of glassy carbon micrometric particles in water using "Rosette" instead of cylindrical reactor, allowed preparing at highest yield (1-2wt%), stable suspensions of carbon nanoparticles, easily separated from the sedimented particles. Both sediment and supernatant separated by decantation of the sonicated dispersions were characterized by laser granulometry, scanning electron microscopy, X-ray microanalysis, and Raman and infrared spectroscopies. Their multiscale organization was investigated by transmission electron microscopy as a function of the sonication time. For sonication longer than 10h, these nanoparticles from supernatant (diameter <50nm) are aggregated. Their structures are more disordered than the sediment particles showing typical nanometer-sized aromatic layer arrangement of glassy carbon, with closed mesopores (diameter ∼3nm). Sonication time longer than 5h has induced not only a strong amorphization (subnanometric and disoriented aromatic layer) but also a loss of the mesoporous network nanostructure. These multi-scale organizational changes took place because of both cavitation and shocks between particles, mainly at the particle surface. The sonication in water has induced also chemical effects, leading to an increase in the oxygen content of the irradiated material together with the sonication time.

  12. Highly biocompatible chitosan with super paramagnetic calcium ferrite (CaFe2O4) nanoparticle for the release of ampicillin.

    PubMed

    Bilas, Ram; Sriram, K; Maheswari, P Uma; Sheriffa Begum, K M Meera

    2017-04-01

    The CaFe2O4 nanoparticles (CFNP) were synthesized using the solution combustion method. The CFNP-chitosan-ampicillin was prepared by the ionic gelation method using tripolyphosphate (TPP). The CFNP, chitosan-CFNP, chitosan-CFNP-ampicillin materials were characterized by XRD, FT-IR and TGA analysis in order to evaluate the particle nature and size, the presence of functional groups and their thermal stability. The FESEM and EDAX analysis were performed to understand the surface morphology of the materials and the presence of CFNP in the material, respectively. The vibrating sample magnetometer (VSM) analysis was performed to analyze the magnetic property of the chitosan-CFNP material. The squareness value of 0.1733 obtained by VSM measurements indicates the super paramagnetic nature of chitosan-CFNP. Taguchi orthogonal array method was applied to identify the significant impacting parameters for maximizing the drug encapsulation of chitosan-CFNP. The drug release studies showed that the drug was released rapidly in acidic medium as compared to the basic or neutral medium. The drug release kinetic data were fitted with different linear kinetic model equations and the best fit was obtained with Korsmeyer-Peppas model. The model drug ampicillin release from chitosan-CFNP was tested against staphylococcus epidermis bacteria through disc diffusion method for checking biocompatibility and antibacterial activity.

  13. Sonochemical synthesis of cobalt aluminate nanoparticles under various preparation parameters.

    PubMed

    Lv, Weizhong; Qiu, Qi; Wang, Fang; Wei, Shaohui; Liu, Bo; Luo, Zhongkuan

    2010-06-01

    Cobalt aluminate (CoAl(2)O(4)) nanoparticles were synthesized using a precursor method with the aid of ultrasound irradiation under various preparation parameters. The effects of the preparation parameters, such as the sonochemical reaction time and temperature, precipitation agents, calcination temperature and time on the formation of CoAl(2)O(4) were investigated. The precursor on heating yields nanosized CoAl(2)O(4) particles and both these nanoparticles and the precursor were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The use of ultrasound irradiation during the homogeneous precipitation of the precursor reduces the duration of the precipitation reaction. The mechanism of the formation of cobalt aluminate was investigated by means of Fourier transformation infrared spectroscopy (FT-IR) and EDX (energy dispersive X-ray). The thermal decomposition process and kinetics of the precursor of nanosized CoAl(2)O(4) were investigated by means of differential scanning calorimetry (DSC) and thermogravimetry (TG). The apparent activation energy (E) and the pre-exponential constant (A) were 304.26 kJ/mol and 6.441 x 10(14)s(-1), respectively. Specific surface area was investigated by means of Brunauer Emmett Teller (BET) surface area measurements.

  14. Structural and complex impedance spectroscopic studies of Ni0.5Mg0.3Cu0.2Fe2O4 ferrite nanoparticle

    NASA Astrophysics Data System (ADS)

    Dhaou, Mohamed Houcine; Hcini, Sobhi; Mallah, Abdulrahman; Bouazizi, Mohamed Lamjed; Jemni, Abdelmajid

    2017-01-01

    Spinel ferrite having composition Ni0.5Mg0.3Cu0.2Fe2O4 was prepared by the sol-gel technique at 1473 K. The X-ray diffraction results indicate that the ferrite sample has a cubic spinel-type structure with Fdbar{3}m space group. The electrical properties of the studied sample using complex impedance spectroscopy technique have been investigated in the frequency range 102-107 Hz and in the temperature range 300-500 K. The total conductivity curves for sample are found to obey Jonscher power law ( σ( ω) = σ dc + Aω n ) with an increase in the frequency exponent ( n) as temperature increases. The activation energy deduced from the analysis of the conductivity curves matches very well with the value estimated from the relaxation time, indicating that relaxation process and electrical conductivity are attributed to the same defect. Nyquist plots of impedance show semicircle arcs for sample, and an electrical equivalent circuit has been proposed to explain the impedance results. The effect of frequency and temperature on dielectric constant ( ɛ″) and dielectric loss (tan δ) has also been discussed in terms of hopping of charge carriers between Fe2+ and Fe3+ ions.

  15. Nanoparticle-assisted laser desorption/ionization mass spectrometry: Novel sample preparation methods and nanoparticle screening for plant metabolite imaging

    SciTech Connect

    Yagnik, Gargey B.

    2016-02-19

    The main goal of the presented research is development of nanoparticle based matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS). This dissertation includes the application of previously developed data acquisition methods, development of novel sample preparation methods, application and comparison of novel nanoparticle matrices, and comparison of two nanoparticle matrix application methods for MALDI-MS and MALDI-MS imaging.

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

    PubMed

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

    2014-10-13

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

  17. Preparation of polymeric nanoparticles containing corticosteroid by a novel aerosol flow reactor method.

    PubMed

    Eerikäinen, Hannele; Kauppinen, Esko I

    2003-09-16

    Polymeric drug-containing nanoparticles were prepared using a novel aerosol flow reactor method. The polymeric drug-containing nanoparticles prepared consist of a poorly water soluble corticosteroid, beclomethasone dipropionate, and polymeric materials Eudragit E 100 or Eudragit L 100. The novel method used in this study allows synthesis of nanoparticles directly as dry powders. The nanoparticles can contain various ratios of drug and polymer, and the use of any additional stabilisation materials is avoided. In this study, nanoparticles with different drug-to-polymer ratios were prepared. Particle size and morphology, crystallinity, and thermal behaviour were determined as a function of particle composition. It was found that all the nanoparticles produced, regardless of particle composition, had geometric number mean diameters of approximately 90 nm, and were spherical showing smooth surfaces. The drug was molecularly dispersed in the amorphous polymeric matrix of the nanoparticles, and drug crystallisation was not observed when the ambient temperature was below the glass transition temperature of the polymer.

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

    PubMed Central

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

    2013-01-01

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

  19. CO responses of sensors based on cerium oxide thick films prepared from clustered spherical nanoparticles.

    PubMed

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

    2013-03-08

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

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

    NASA Astrophysics Data System (ADS)

    Gao, Zhe

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

  1. Size dependence of magnetorheological properties of cobalt ferrite ferrofluid

    SciTech Connect

    Radhika, B.; Sahoo, Rasmita; Srinath, S.

    2015-06-24

    Cobalt Ferrite nanoparticles were synthesized using co-precipitation method at reaction temperatures of 40°C and 80°C. X-Ray diffraction studies confirm cubic phase formation. The average crystallite sizes were found to be ∼30nm and ∼48nm for 40°C sample and 80°C sample respectively. Magnetic properties measured using vibrating sample magnetometer show higher coercivety and magnetization for sample prepared at 80°C. Magnetorheological properties of CoFe2O4 ferrofluids were measured and studied.

  2. Size dependence of magnetorheological properties of cobalt ferrite ferrofluid

    NASA Astrophysics Data System (ADS)

    Radhika, B.; Sahoo, Rasmita; Srinath, S.

    2015-06-01

    Cobalt Ferrite nanoparticles were synthesized using co-precipitation method at reaction temperatures of 40°C and 80°C. X-Ray diffraction studies confirm cubic phase formation. The average crystallite sizes were found to be ˜30nm and ˜48nm for 40°C sample and 80°C sample respectively. Magnetic properties measured using vibrating sample magnetometer show higher coercivety and magnetization for sample prepared at 80°C. Magnetorheological properties of CoFe2O4 ferrofluids were measured and studied.

  3. Synthesis and Characterization of Nickel Zinc Ferrite

    NASA Astrophysics Data System (ADS)

    Kurian, Manju; Nair, Divya S.

    2011-10-01

    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 found to be in the range 8.31-8.41Ao. This confirms that nano crystalline ferrite samples are in the cubic spinel structure. An average nano crystalline size was estimated from XRD by the Scherrer's equation. FTIR study also confirms the formation of ferrites. Sol-gel auto combustion technique was superior to co-precipitation method for producing single phase nano particles with smaller crystallite size.

  4. Conductive grid patterns prepared by microcontact printing silver nanoparticles ink

    NASA Astrophysics Data System (ADS)

    Xin, Zhiqing; Liu, Yu; Li, Xiu; Liu, Shili; Fang, Yi; Deng, Yongqiang; Bao, Chao; Li, Luhai

    2017-01-01

    Metal grid transparent conductive electrodes have been developed by traditional printing techniques, but lower resolution of grid line has limited its performance. In this study, conductive grid patterns with ~10 µm width were created on the polyethylene terephthalate (PET) substrate by microcontact printing (µCP) silver nanoparticles ink. We have found that the composition of silver nanoparticles ink and the O2 plasma treated time of polydimethylsiloxane (PDMS) stamp were critical for the µCP process. Specially, the hole size of stamp has great influence on the patterns shape when using grid-structured stamp. This is because the break of liquid bridge formed between two adjacent lines of stamp depends on the hole size of stamp during the dry process of ink. Larger hole was beneficial for the formation of grid patterns with smooth edge. Conductive grid patterns with typical sheet resistance of 610 Ω/□ and 74% transparency were acquired over the entire 1 cm square area using 40 µm hole stamp. This method will lead to a facile strategy to prepare conductive electrode.

  5. Preparation and characterization of solid lipid nanoparticles loaded with doxorubicin.

    PubMed

    Subedi, Robhash Kusam; Kang, Keon Wook; Choi, Hoo-Kyun

    2009-06-28

    Solid lipid nanoparticles (SLN) loaded with doxorubicin were prepared by solvent emulsification-diffusion method. Glyceryl caprate (Capmul)MCM C10) was used as lipid core, and curdlan as the shell material. Dimethyl sulfoxide (DMSO) was used to dissolve both lipid and drug. Polyethylene glycol 660 hydroxystearate (Solutol)HS15) was employed as surfactant. Major formulation parameters were optimized to obtain high quality nanoparticles. The mean particle size measured by photon correlation spectroscopy (PCS) was 199nm. The entrapment efficiency (EE) and drug loading capacity (DL), determined with fluorescence spectroscopy, were 67.5+/-2.4% and 2.8+/-0.1%, respectively. The drug release behavior was studied by in vitro method. Cell viability assay showed that properties of SLN remain unchanged during the process of freeze-drying. Stability study revealed that lyophilized SLN were equally effective (p<0.05) after 1 year of storage at 4 degrees C. In conclusion, SLN with small particle size, high EE, and relatively high DL for doxorubicin can be obtained by this method.

  6. Preparation and protein immobilization of magnetic dialdehyde starch nanoparticles.

    PubMed

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

    2013-04-11

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

  7. Phytotoxicity of Ag nanoparticles prepared by biogenic and chemical methods

    NASA Astrophysics Data System (ADS)

    Choudhury, Rupasree; Majumder, Manna; Roy, Dijendra Nath; Basumallick, Srijita; Misra, Tarun Kumar

    2016-06-01

    Silver nanoparticles (Ag NPs) are now widely used as antibacterial and antifungal materials in different consumer products. We report here the preparation of Ag NPs by neem leaves extract ( Azadirachta) reduction and trisodium citrate-sodium borohydride reduction methods, and study of their phytotoxicity. The nanoparticles were characterized by UV-Vis spectroscopy, FTIR, and atomic force microscopy (AFM) techniques. Both neem-coated and citrate-coated Ag NPs exhibit surface plasmon around 400 nm, and their average sizes measured by AFM are about 100 and 20 nm, respectively. Antibacterial and antifungal activities of these nanomaterials have been studied by simple pea seed germination and disk diffusion methods. It has been observed from the growth of root and shoot, citrate-coated Ag NPs significantly affect seedling growth, but neem-coated Ag NPs exhibit somehow mild toxicity toward germination process due to the nutrient supplements from neem. On the other hand, antifungal activity of neem-coated Ag NPs has been found much higher than that of citrate-coated Ag NPs due to the combined effects of antifungal activity of neem and Ag NPs. Present research primarily indicates a possible application of neem-coated Ag NPs as a potential fungicide.

  8. Preparation of silver nanoparticles fabrics against multidrug-resistant bacteria

    NASA Astrophysics Data System (ADS)

    Hanh, Truong Thi; Thu, Nguyen Thi; Hien, Nguyen Quoc; An, Pham Ngoc; Loan, Truong Thi Kieu; Hoa, Phan Thi

    2016-04-01

    The silver nanoparticles (AgNPs)/peco fabrics were prepared by immobilization of AgNPs on fabrics in which AgNPs were synthesized by γ-irradiation of the 10 mM AgNO3 chitosan solution at the dose of 17.6 kGy. The AgNPs size has been estimated to be about 11 nm from TEM image. The AgNPs content onto peco fabrics was of 143±6 mg/kg at the initial AgNPs concentration of 100 ppm. The AgNPs colloidal solution was characterized by UV-vis spectroscopy and TEM image. The antibacterial activity of AgNPs/peco fabrics after 60 washings against Staphylococcus aureus and Klebsiella pneumoniae was found to be over 99%. Effects of AgNPs fabics on multidrug-resistant pathogens from the clinical specimens were also tested.

  9. Preparation and Evaluation of Montelukast Sodium Loaded Solid Lipid Nanoparticles

    PubMed Central

    Priyanka, K; Sathali, A Abdul Hasan

    2012-01-01

    Solid lipid nanoparticles (SLNs) are an alternative carrier system used to load the drug for targeting, to improve the bioavailability by increasing its solubility, and protecting the drug from presystemic metabolism. The avoidance of presystemic metabolism is due to the nano-metric size range, so that the liver cannot uptake the drug from the delivery system and is not metabolized by the liver. Montelukast sodium is an anti-asthmatic drug, because of its poor oral bioavailability, presystemic metabolism, and decreased half-life; it was chosen to formulate as the solid lipid nanoparticle (SLN) system by hot homogenization followed by an ultrasonication method, to overcome the above. Compritol ATO 888, stearic acid, and glyceryl monostearate were used as a lipid matrix and polyvinyl alcohol as a surfactant. The prepared formulations have been evaluated for entrapment efficiency, drug content, in vitro drug release, particle size analysis, scanning electron microscopy, Fourier transform-infrared studies (FT-IR), differential scanning calorimetry (DSC), and stability. Particle size analysis revealed that the SLN prepared from the higher melting point lipid showed a larger particle size and with increased carbon chain length of the fatty acids. Entrapment efficiency (EE) was ranging from 42% to 92%. In vitro release studies showed maximum cumulative drug release was obtained for F 1 (59.1%) containing stearic acid, and the lowest was observed for F 18 (28.1%) containing compritol ATO 888 after 12 h and all the formulations followed first-order release kinetics. FT-IR and DSC studies revealed no interaction between drug and lipids. Studies showed that increase in lipid concentration, increased particle size, EE, and maintained the sustained release of drug. Among all, compritol ATO 888 was chosen as the best lipid for formulating SLN because it had high EE and sustained the drug release. PMID:23112531

  10. Nanoparticles containing ketoprofen and acrylic polymers prepared by an aerosol flow reactor method.

    PubMed

    Eerikäinen, Hannele; Peltonen, Leena; Raula, Janne; Hirvonen, Jouni; Kauppinen, Esko I

    2004-09-23

    The purpose of this study was to outline the effects of interactions between a model drug and various acrylic polymers on the physical properties of nanoparticles prepared by an aerosol flow reactor method. The amount of model drug, ketoprofen, in the nanoparticles was varied, and the nanoparticles were analyzed for particle size distribution, particle morphology, thermal properties, IR spectroscopy, and drug release. The nanoparticles produced were spherical, amorphous, and had a matrix-type structure. Ketoprofen crystallization was observed when the amount of drug in Eudragit L nanoparticles was more than 33% (wt/wt). For Eudragit E and Eudragit RS nanoparticles, the drug acted as an effective plasticizer resulting in lowering of the glass transition of the polymer. Two factors affected the preparation of nanoparticles by the aerosol flow reactor method, namely, the solubility of the drug in the polymer matrix and the thermal properties of the resulting drug-polymer matrix.

  11. Pulsed electric field assisted sol-gel preparation of TiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Mani, Rajaboopathi; Han, Bing; Louhi-Kultanen, Marjatta

    2016-10-01

    This work studies the effect of a pulsed electric field (PEF) on the precipitation and properties of TiO2 nanoparticles. TiO2 nanoparticles were prepared using pulsed DC electric field assisted sol-gel method. The duration of the PEF treatment was varied to investigate its effect on the particle size of TiO2 nanoparticles. The nanoparticles were characterized by X-ray powder diffraction (XRD), Raman spectroscopy, UV diffuse reflectance spectroscopy (UV-DRS) and transmission electron microscopy (TEM). It was found that TiO2 particles prepared with pulsed electric field assisted sol-gel method had enhanced average crystallite size due to the effect of the pulsed electric field on primary nucleation. The effect of electric field on nanoparticle preparation is interesting which can be used to control the grain and crystallite size of nanoparticle.

  12. Mössbauer and magnetization studies of nickel ferrite nanoparticles synthesized by the microwave-combustion method

    NASA Astrophysics Data System (ADS)

    Mahmoud, M. H.; Elshahawy, A. M.; Makhlouf, Salah A.; Hamdeh, H. H.

    2013-10-01

    Nanocrystalline nickel ferrite was synthesized from its stoichiometric metal nitrates and urea mixtures, using a microwave assisted combustion method. The process was a convenient, inexpensive and an efficient method for formation of NiFe2O4 nanomaterials. Effect of urea/metal nitrates ratio on the obtained phases, particle size and magnetic properties has been investigated by various techniques. Saturation magnetization of 50 emu/g was observed at room temperature for larger particles, and it decreases with decreasing particle size. The coercivity attains a maximum value of 170 Oe when the particle size was ~20 nm, and decreases with increasing particle size. Mössbauer spectra measured at RT for some representative samples show a combination of ordered and superparamagnetic behavior, whereas those collected at 20 K elucidate the nature of the obtained phases and cation distribution.

  13. Preparation of Chitosan nanoparticles and its effect on detached rice leaves infected with Pyricularia grisea.

    PubMed

    Manikandan, Appu; Sathiyabama, Muthukrishnan

    2016-03-01

    The aim of the present study was to prepare chitosan nanoparticles to evaluate their effect on protection of rice plants from blast fungus. Nanoparticles were prepared using the ionic gelation method by the interaction of Chitosan and sodium tripolyphosphate. The particle size, polydispersity index, zetapotential and structure was confirmed by DLS, FTIR, TEM and XRD. The Chitosan nanoparticle was evaluated for suppression of rice blast fungus (Pyricularia grisea) under the detached leaf condition. It is evident from our results that chitosan nanoparticle have potential in suppressing blast disease of rice which can be used further under field condition to protect rice plants from the devastating fungus.

  14. Heat treatment effects on structural and dielectric properties of Mn substituted CuFe2O4 and ZnFe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ranjith Kumar, E.; Arunkumar, T.; Prakash, T.

    2015-09-01

    Manganese substituted copper and zinc ferrite nanoparticles were synthesized by an auto-combustion technique using metal nitrates and urea. The nanoparticles were characterized by XRD, SEM, EDX, and TEM techniques. The effect of annealing temperature on structural and dielectric properties of Mn substituted spinel ferrite nanoparticles was analyzed. The presenting elements in the prepared samples are recorded by EDX. TEM analysis clearly showed the particles are in the nanometer range. The dielectric loss and dielectric constant have been measured in the frequency range of 100 kHz-5 MHz. The variation in structural and dielectric properties of the prepared and annealed samples are discussed.

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

    PubMed

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

    2015-05-05

    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 10-30 nm. 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.

  16. Preparation and Characterization of MWCNT/ZnO nanoparticles Hybrid

    NASA Astrophysics Data System (ADS)

    Sameera, I.; Bhatia, Ravi; Prasad, V.

    2010-10-01

    ZnO nanoparticles (ZnO NPs) were grown on the surface of multiwall carbon nanotubes (MWCNTs) by a wet chemical synthesis route. The anchoring of ZnO NPs on acid-treated MWCNTs was achieved under remarkably mild reaction conditions (low temperature, atmospheric pressure, without any capping agents and no need for subsequent thermal annealing). MWCNT/ZnO NPs hybrid samples with varying loading of ZnO NPs are prepared. A very high degree of dispersion of ZnO NPs over the surface of MWCNT was achieved by suitably controlling the ratio of ZnO NPs and MWCNTs in the solution. The hybrid sample was characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy (XPS). Transmission electron microscope images of the as-prepared MWCNT/ZnO NPs hybrid reveal that mono-dispersed ZnO NPs are anchored stably on functionalized MWCNTs. The interaction of ZnO NPs with MWCNT surface was interpreted through XPS analysis.

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

    PubMed Central

    2013-01-01

    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

  18. 2-Amino-2-deoxy-glucose conjugated cobalt ferrite magnetic nanoparticle (2DG-MNP) as a targeting agent for breast cancer cells.

    PubMed

    Aşık, Elif; Aslan, Tuğba Nur; Volkan, Mürvet; Güray, N Tülin

    2016-01-01

    In this study, 2-amino-2-deoxy-glucose (2DG) was conjugated to COOH modified cobalt ferrite magnetic nanoparticles (COOH-MNPs), which were designed to target tumor cells as a potential targetable drug/gene delivery agent for cancer treatment. According to our results, it is apparent that, 2DG labeled MNPs were internalized more efficiently than COOH-MNPs under the same conditions in all cell types (MDA-MB-231 and MCF-7 cancer and MCF-10A normal breast cells) (p<0.001). Moreover, the highest amount of uptake was observed in MDA-MB-231, followed by MCF-7 and normal MCF-10A cells for both MNPs. The apoptotic effects of 2DG-MNPs were further evaluated, and it was found that apoptosis was not induced at low concentrations of 2DG-MNPs in all cell types, whereas dramatic cell death was observed at higher concentrations. In addition, the gene expression levels of four drug-metabolizing enzymes, two Phase I (CYP1A1, CYP1B1) and two Phase II (GSTM3, GSTZ1) were also increased with the high concentrations of 2DG-MNPs.

  19. Dextrin-coated zinc substituted cobalt-ferrite nanoparticles as an MRI contrast agent: In vitro and in vivo imaging studies.

    PubMed

    Sattarahmady, N; Zare, T; Mehdizadeh, A R; Azarpira, N; Heidari, M; Lotfi, M; Heli, H

    2015-05-01

    Application of superparamagnetic iron oxide nanoparticles (NPs) as a negative contrast agent in magnetic resonance imaging (MRI) has been of widespread interest. These particles can enhance contrast of images by altering the relaxation times of the water protons. In this study, dextrin-coated zinc substituted cobalt-ferrite (Zn0.5Co0.5Fe2O4) NPs were synthesized by a co-precipitation method, and the morphology, size, structure and magnetic properties of the NPs were investigated. These NPs had superparamagnetic behavior with an average size of 3.9 (±0.9, n=200)nm measured by transmission electron microscopy. Measurements on the relaxivities (r2 and r2(*)) of the NPs were performed in vitro by agarose phantom. In addition, after subcutaneous injection of the NPs into C540 cell line in C-57 inbred mice, the relaxivities were measured in vivo by a 1.5T MRI system. These NPs could effectively increase the image contrast in both T2-and T2(*)-weighted samples.

  20. The preparation, physicochemical properties, and the cohesive energy of liquid sodium containing titanium nanoparticles

    NASA Astrophysics Data System (ADS)

    Saito, Jun-ichi; Itami, Toshio; Ara, Kuniaki

    2012-12-01

    Liquid sodium containing titanium nanoparticles (LSnanop) of 10-nm diameter was prepared by dispersing titanium nanoparticles (2 at.% Ti) into liquid sodium with the addition of stirring and ultrasonic sound wave. The titanium nanoparticles themselves were prepared by the vapor deposition method. This new liquid metal, LSnanop, shows a remarkable stability due to the Brownian motion of nanoparticles in liquid sodium medium. In addition, the difference of measured heat of reaction to water between this LSnanop and liquid sodium indicates the existence of cohesive energy between the liquid sodium medium and dispersed titanium nanoparticles. The origin of the cohesive energy, which serves to stabilize this new liquid metal, was explained by the model of screened nanoparticles in liquid sodium. In this model, negatively charged nanoparticles with transferred electrons from liquid sodium are surrounded by the positively charged screening shell, which may inhibit the gathering of nanoparticles by the "Coulombic repulsion coating." The atomic volume of LSnanop shows the shrinkage from the linear law, which also suggests the existence of cohesive energy. The viscosity of LSnanop is almost the same as that of liquid sodium. This behavior was explained by the Einstein equation. The surface tension of LSnanop is 17 % larger than that of liquid sodium. The cohesive energy and the negative adsorption may be responsible to this increase. Titanium nanoparticles in liquid sodium seem to be free from the Coulomb fission. This new liquid metal containing nanoparticles suggests the possibility to prepare various stable suspensions with new properties.

  1. Facile synthetic route to nanosized ferrites by using mesoporous silica as a hard template

    NASA Astrophysics Data System (ADS)

    Valdés-Solís, T.; Tartaj, P.; Marbán, G.; Fuertes, A. B.

    2007-04-01

    Spinel ferrite nanoparticles (AFe2O4; A = Mn, Ni, Cu, Co) of around 10-20 nm have been successfully synthesized via a simple nanocasting route using metal nitrates as precursors and mesoporous silica gel as a hard template. Spinel nanoparticles were formed under a nitrogen atmosphere by the high-temperature decomposition of a mixture of metal nitrates that fill the silica pores. The decomposition reactions occurred in the confined space provided by the mesopores of the silica template. Under these conditions, the silica walls restricted the growth of the oxide particles formed and so nanosized particles were obtained. The incorporation of different cations into the spinel ferrite enabled us to easily modulate the magnetic properties of the nanomaterials prepared by the template method. Depending on the chemical composition and temperature, we were able to obtain samples that display reversible magnetic behaviour (zero coercivity field) and samples with coercivity values as high as 1.3 T (13 000 Oe).

  2. Barium carbonate nanoparticle to enhance oxygen reduction activity of strontium doped lanthanum ferrite for solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Hong, Tao; Chen, Fanglin; Xia, Changrong

    2015-03-01

    BaCO3 nanoparticles are demonstrated as outstanding catalysts for high-temperature oxygen reduction reaction (ORR) on the La0.8Sr0.2FeO3-δ (LSF) cathode for solid oxide fuel cells (SOFCs) based on ytrria-stabilized zirconia (YSZ) electrolytes. Thermal gravitational and X-ray diffraction measurements show that BaCO3 is stable and chemically compatible with LSF under the fabrication and operation conditions of intermediate-temperature SOFCs. The BaCO3 nanoparticles can greatly reduce the interfacial polarization resistance; from 2.96 to 0.84 Ω cm2 at 700 °C when 12.9wt% BaCO3 is infiltrated to the porous LSF electrode on the YSZ electrolyte. Electrochemical impedance spectroscopy shows that there is about one order of magnitude decrease in the low-frequency resistance, indicating that BaCO3 nanoparticles can greatly enhance the surface steps for ORR. Electrical conductivity relaxation investigation indicates about one order of magnitude increase in the chemical oxygen surface exchange coefficient when BaCO3 is applied, directly demonstrating significant increase in the kinetics for ORR. In addition, LSF cathodes with infiltrated BaCO3 nanoparticles have shown excellent stability and substantially enhanced cell performance as demonstrated with single cells, suggesting BaCO3 nanoparticles are very effective in enhancing ORR on LSF.

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

    PubMed

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

    2011-01-12

    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.

  4. Effect of heat treatment on structural and Mössbauer spectroscopic properties of coprecipitated Mn{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} ferrite nanoparticles

    SciTech Connect

    Srinivas, Ch.; Babu, Ch. Seshu; Tirupanyam, B. V.; Meena, S. S.; Sastry, D. L.

    2015-06-24

    Results obtained in a systamatic study by X-ray diffraction and Mösssbauer spectroscopy on the structural and magnetic properties on Mn{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} ferrite nanoparticles heat treated at 200 °C, 500 °C and 800 °C are reported. Average crystallite sizes are estimated to be in the range (2.6nm – 12.8nm). It is observed that crystallite sizes increase with increase in sintering temperature and random variation in lattice parameter was observed. At relatively low sintering temperatures the samples exhibit superparamagnetism and complete ferrite phase was observed at higher heat treatment.

  5. Investigation of antibacterial properties silver nanoparticles prepared via green method

    PubMed Central

    2012-01-01

    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

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

    PubMed

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

    2014-04-01

    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.

  7. Chitosan graft copolymer nanoparticles for oral protein drug delivery: preparation and characterization.

    PubMed

    Qian, Feng; Cui, Fuying; Ding, Jieying; Tang, Cui; Yin, Chunhua

    2006-10-01

    Several novel functionalized graft copolymer nanoparticles consisting of chitosan (CS) and the monomer methyl methacrylate (MMA), N-dimethylaminoethyl methacrylate hydrochloride (DMAEMC), and N-trimethylaminoethyl methacrylate chloride (TMAEMC), which show a higher solubility than chitosan in a broader pH range, have been prepared by free radical polymerization. The nanoparticles were characterized in terms of particle size, zeta potential, TEM, and FT-IR. These nanoparticles were 150-280 nm in size and carried obvious positive surface charges. Protein-loaded nanoparticles were prepared, and their maximal encapsulation efficiency was up to 100%. In vitro release showed that these nanoparticles provided an initial burst release followed by a slowly sustained release for more than 24 h. These graft copolymer nanoparticles enhanced the absorption and improved the bioavailability of insulin via the gastrointestinal (GI) tract of normal male Sprague-Dawley (SD) strain rats to a greater extent than that of the phosphate buffer solution (PBS) of insulin.

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

    PubMed

    Khoee, S; Bagheri, Y; Hashemi, A

    2015-03-07

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  10. Preparation and characterization of hybrid nanoparticles based on chitosan and poly(methacryloylglycylglycine)

    NASA Astrophysics Data System (ADS)

    Ferri, Marcella; Dash, Mamoni; Cometa, Stefania; De Giglio, Elvira; Sabbatini, Luigia; Chiellini, Federica

    2014-05-01

    The present work investigated the possibility of preparing nanoparticles based on methacryloylglycylglycine (MAGG) and chitosan (CS) by in situ polymerization. The study revealed that nanoparticle formation was strictly dependent on ionic interactions between NH3 + groups from CS and COO- groups arising from the anionic monomer MAGG. The subsequent in situ polymerizations of MAGG in the presence of CS led to the formation of nanoparticles with homogeneous morphology, a uniform particle size distribution, and a good spherical shape as confirmed by laser diffraction granulometry and scanning electron microscopy analyses. Nanoparticle formulations with different amounts of CS and MAGG were prepared, and their chemical compositions were investigated by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The obtained results showed that the polymerization of MAGG in the presence of CS appears to be a very promising approach in the preparation of nanoparticles for drug delivery applications.

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

    PubMed

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

    2011-11-03

    Preparation conditions of a DNA vaccine against swine influenza encapsulated in chitosan nanoparticles were determined. The nanoparticles were prepared according to a complex coacervation method using chitosan as a biodegradable matrix forming polymer. Under the preparation conditions, chitosan nanoparticles containing the DNA vaccine were produced with good morphology, high encapsulation rate and high stability. Transfection test indicated that the vaccine could be expressed as an antigen in cells, and maintained good bioactivity. In addition, better immune responses of mice immunized with the chitosan nanoparticles containing the DNA vaccine were induced and prolonged release of the plasmid DNA was achieved compared to the DNA vaccine alone. These results laid a foundation for further development of DNA vaccines in nanoparticles before ultimate industrial application.

  12. Preparation and characterization of silver chloride nanoparticles as an antibacterial agent

    NASA Astrophysics Data System (ADS)

    Duong Trinh, Ngoc; Thanh Binh Nguyen, Thi; Hai Nguyen, Thanh

    2015-12-01

    Silver chloride nanoparticles were prepared by the precipitation reaction between silver nitrate and sodium chloride in an aqueous solution containing poly(vinyl alcohol) as a stabilizing agent. Different characteristics of the nanoparticles in suspension and in lyophilized powder such as size, morphology, chemical nature, interaction with stabilizing agent and photo-stability were investigated. Biological tests showed that the obtained silver chloride nanoparticles displayed antibacterial activities against Escherichia coli and Staphylococcus aureus.

  13. Preparation of neutron-activatable holmium nanoparticles for the treatment of ovarian cancer metastases.

    PubMed

    Di Pasqua, Anthony J; Huckle, James E; Kim, Jin-Ki; Chung, Younjee; Wang, Andrew Z; Jay, Michael; Lu, Xiuling

    2012-04-10

    Nanoparticles containing stable holmium ((165) Ho) are prepared by nanotemplate engineering and subsequently irradiated in a neutron flux to yield (166) Ho, a beta-emitting radiotherapeutic isotope. After intraperitoneal injection to mice bearing SKOV-3 ovarian tumors, significant tumor accumulation of the (166) Ho-nanoparticles is observed by SPECT imaging indicating the potential of these neutron activatable nanoparticles for internal radiation therapy of ovarian cancer metastases.

  14. Synthesis and Optical Properties of Sulfide Nanoparticles Prepared in Dimethylsulfoxide

    SciTech Connect

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

    2008-11-01

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

  15. High frequency AC response, DC resistivity and magnetic studies of holmium substituted Ni-ferrite: A novel electromagnetic material

    NASA Astrophysics Data System (ADS)

    Pervaiz, Erum; Gul, I. H.

    2014-01-01

    Nanoparticles of holmium substituted nickel ferrites (NiHoxFe2-xO4) with x ranging from 0.0 to 0.15 have been prepared by the sol-gel auto-combustion method. Structural and morphology studies have been performed by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). XRD patterns revealed the formation of pure spinel phase ferrites without any impurity phase. Lattice parameter increases along with a decrease in crystallite size with increasing the concentration of Ho3+ in the parent nickel ferrite due to large ionic radius of Ho3+ (0.901 Å) as compared to Fe3+ (0.67 Å). SEM shows the spherical, uniformly distributed homogenous nanoparticles grown by controlled reaction parameters of the sol-gel method. Complex permittivity (ɛ*) and complex electric modulus (M*) have been studied for the present nanoferrites in the frequency ranges of 1 MHz-1 GHz. Frequency dependent dielectric parameters (relative permittivity (ɛ'), dielectric loss (ɛ″), dielectric loss tangent (tan δ)) decreases due to holmium substitution in nickel ferrites, showing the electrical conduction is decreasing in the nickel holmium ferrites with increase in the concentration of holmium. Complex modulus plots shows the poorly resolved semi circles and relaxation of nanoferrite is studied in the high frequency region. Also the relaxation time increases due to increase in x (0.0-0.15). DC electrical resistivity increases (107 Ω-cm-1010 Ω-cm) due to holmium ions substitution in nickel ferrites. Magnetic behavior was also characterized using a Vibrating Sample Magnetometer (VSM) under an applied magnetic field of 10 kOe and shows that magnetization decreases with increase in composition of holmium in nickel ferrites. High frequency behavior, low losses and very high DC electrical resistivity made the material a novel one for electromagnetic devices.

  16. The morphology of silver nanoparticles prepared by enzyme-induced reduction.

    PubMed

    Schneidewind, Henrik; Schüler, Thomas; Strelau, Katharina K; Weber, Karina; Cialla, Dana; Diegel, Marco; Mattheis, Roland; Berger, Andreas; Möller, Robert; Popp, Jürgen

    2012-01-01

    Silver nanoparticles were synthesized by an enzyme-induced growth process on solid substrates. In order to customize the enzymatically grown nanoparticles (EGNP) for analytical applications in biomolecular research, a detailed study was carried out concerning the time evolution of the formation of the silver nanoparticles, their morphology, and their chemical composition. Therefore, silver-nanoparticle films of different densities were investigated by using scanning as well as transmission electron microscopy to examine their structure. Cross sections of silver nanoparticles, prepared for analysis by transmission electron microscopy were additionally studied by energy-dispersive X-ray spectroscopy in order to probe their chemical composition. The surface coverage of substrates with silver nanoparticles and the maximum particle height were determined by Rutherford backscattering spectroscopy. Variations in the silver-nanoparticle films depending on the conditions during synthesis were observed. After an initial growth state the silver nanoparticles exhibit the so-called desert-rose or nanoflower-like structure. This complex nanoparticle structure is in clear contrast to the auto-catalytically grown spherical particles, which maintain their overall geometrical appearance while increasing their diameter. It is shown, that the desert-rose-like silver nanoparticles consist of single-crystalline plates of pure silver. The surface-enhanced Raman spectroscopic (SERS) activity of the EGNP structures is promising due to the exceptionally rough surface structure of the silver nanoparticles. SERS measurements of the vitamin riboflavin incubated on the silver nanoparticles are shown as an exemplary application for quantitative analysis.

  17. Preparation, characterization and in vitro antiviral activity evaluation of foscarnet-chitosan nanoparticles.

    PubMed

    Russo, E; Gaglianone, N; Baldassari, S; Parodi, B; Cafaggi, S; Zibana, C; Donalisio, M; Cagno, V; Lembo, D; Caviglioli, G

    2014-06-01

    A new nanoparticulate system for foscarnet delivery was prepared and evaluated. Nanoparticles were obtained by ionotropic gelation of chitosan induced by foscarnet itself, acting as an ionotropic agent in a manner similar to tripolyphosphate anion. A Doehlert design allowed finding the suitable experimental conditions. Nanoparticles were between 200 and 300nm in diameter (around 450nm after redispersion). Nanoparticle size increased after 5h, but no size increase was observed after 48h when nanoparticles were crosslinked with glutaraldehyde. Zeta potential values of noncrosslinked and crosslinked nanoparticles were between 20 and 25mV, while drug loading of noncrosslinked nanoparticles was about 40% w/w (55% w/w for crosslinked nanoparticles). Nanoparticle yield was around 25% w/w. Crosslinked nanoparticles showed a controlled drug release. Foscarnet released from nanoparticles maintained the antiviral activity of the free drug when tested in vitro against lung fibroblasts (HELF) cells infected with HCMV strain AD-169. Moreover, nanoparticles showed no toxicity on non-infected HELF cells. These nanoparticles may represent a delivery system that could improve the therapeutic effect of foscarnet.

  18. Comparison study of the magnetic permeability and dc conductivity of Co-Ni-Li ferrite nanoparticles and their bulk counterparts

    NASA Astrophysics Data System (ADS)

    Assar, S. T.; Abosheiasha, H. F.; El Nimr, M. K.

    2014-03-01

    The temperature dependence of relative permeability and dc electrical conductivity of nanosamples and their bulk counterparts of Co0.5Ni0.5-2xLixFe2+xO4 (from x=0.00 to 0.25 in step of 0.05) was investigated. The values of the relative permeability of the nano-samples are lower than their bulk counterparts as a result of porous and nano-grained structure besides the effect of the larger volume of grain boundaries in the nanosamples. Moreover, the dc conductivity of the nanosamples is higher than their bulk counterparts. This is probable explained according to the shorter metal-oxygen bonding length and higher lattice vibrations of the nanosamples. Also, the values of the relative permeability of both nano and bulk samples exhibit stability over a considerable range of temperatures. This may make them useful in practical applications that require stability. All the nanosamples show high rising Curie temperature values with increasing the Li content up to the sample of x=0.15 thereafter a decrease of the Curie temperature occurs while the inverse behavior was observed in their bulk counterparts. The interpretation of these findings is explained in the discussion. Moreover, in general doping Co-Ni ferrites with Li ions improves their electrical and magnetic properties and this is clearly observed in the nanosample of x=0.15 which can be regarded as the most promising sample for microwave applications.

  19. Hyperfine interaction and tuning of magnetic anisotropy of Cu doped CoFe2O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Batoo, Khalid Mujasam; Salah, Dina; Kumar, Gagan; Kumar, Arun; Singh, Mahavir; Abd El-sadek, M.; Mir, Feroz Ahmad; Imran, Ahamad; Jameel, Daler Adil

    2016-08-01

    Ferrimagnetic oxides may contain single or multi domain particles which get converted into superparamagnetic state near a critical size. To explore the existence of these particles, we have made Mössbauer and magnetic studies of Cu2+ substitution effect in CoFe2-xO4 Ferrites (0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). All the samples have a cubic spinel structure with lattice parameters increasing linearly with increase in Cu content. The hysteresis loops yield a saturation magnetization, coercive field, and remanent magnetization that vary significantly with Cu content. The magnetic hysteresis curves shows a reduction in saturation magnetization and an increase in coercitivity with Cu2+ ion substitution. The anisotropy constant, K1, is found strongly dependent on the composition of Cu2+ ions. The variation of saturation magnetization with increasing Cu2+ ion content has been explained in the light of Neel's molecular field theory. Mössbauer spectra at room temperature shows two ferrimagnetically relaxed Zeeman sextets. The dependence of Mössbauer parameters such as isomer shift, quadrupole splitting, line width and hyperfine magnetic field on Cu2+ ion concentration have been discussed.

  20. Cobalt ferrite nanoparticles decorated on exfoliated graphene oxide, application for amperometric determination of NADH and H2O2.

    PubMed

    Ensafi, Ali A; Alinajafi, Hossein A; Jafari-Asl, M; Rezaei, B; Ghazaei, F

    2016-03-01

    Here, cobalt ferrite nanohybrid decorated on exfoliated graphene oxide (CoFe2O4/EGO) was synthesized. The nanohybrid was characterized by different methods such as X-ray diffraction spectroscopy, scanning electron microscopy, energy dispersive X-ray diffraction microanalysis, transmission electron microscopy, FT-IR, Raman spectroscopy and electrochemical methods. The CoFe2O4/EGO nanohybrid was used to modify glassy carbon electrode (GCE). The voltammetric investigations showed that CoFe2O4/EGO nanohybrid has synergetic effect towards the electro-reduction of H2O2 and electro-oxidation of nicotinamide adenine dinucleotide (NADH). Rotating disk chronoamperometry was used for their quantitative analysis. The calibration curves were observed in the range of 0.50 to 100.0 μmol L(-1) NADH and 0.9 to 900.0 μmol L(-1) H2O2 with detections limit of 0.38 and 0.54 μmol L(-1), respectively. The repeatability, reproducibility and selectivity of the electrochemical sensor for analysis of the analytes were studied. The new electrochemical sensor was successfully applied for the determination of NADH and H2O2 in real samples with satisfactory results.

  1. Improved corneal toxicity and permeability of tranilast by the preparation of ophthalmic formulations containing its nanoparticles.

    PubMed

    Nagai, Noriaki; Ono, Hikaru; Hashino, Miho; Ito, Yoshimasa; Okamoto, Norio; Shimomura, Yoshikazu

    2014-01-01

    We prepared ophthalmic formulations containing 0.5% tranilast (TL) nanoparticles using 0.005% benzalkonium chloride (BAC), 0.5% D-mannitol, and 2-hydroxypropyl-β-cyclodextrin (HPβCD), and investigated their usefulness in the ophthalmologic field by evaluating corneal toxicity and permeability. TL nanoparticles were prepared using zirconia beads and Bead Smash 12, which allowed the preparation of high quality dispersions containing 0.5% TL nanoparticles (particle size, 34 ± 20 nm, means ± S.D.). Dispersions containing TL nanoparticles are tolerated better by human corneal epithelium cells than a commercially available 0.5% TL preparation (RIZABEN(®) eye drops). In addition, the addition of TL nanoparticles to the dispersions does not affect the antimicrobial activity of BAC against Escherichia coli (ATCC 8739), and the corneal penetration of TL from dispersions containing TL nanoparticles was significantly higher than in the case of the commercially available 0.5% TL eye drops. It is possible that dispersions containing TL nanoparticles will show increased effectiveness against ocular inflammation, and that ocular drug delivery systems using drug nanoparticles may lead to an expansion of their usefulness for therapy in the ophthalmologic field.

  2. Preparation of gelatin films incorporated with tea polyphenol nanoparticles for enhancing controlled-release antioxidant properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tea polyphenols (TP) were incorporated into edible gelatin films either alone or incorporated into nanoparticles in order to determine the physico-chemical properties of the film and the antioxidant properties of TP in a solid gelatin matrix. The TP containing nanoparticles were prepared by cross-li...

  3. Metal nanoparticle deposited inorganic nanostructure hybrids, uses thereof and processes for their preparation

    DOEpatents

    Tenne, Reshef; Tsverin, Yulia; Burghaus, Uwe; Komarneni, Mallikharjuna Rao

    2016-01-26

    This invention relates to a hybrid component comprising at least one nanoparticle of inorganic layered compound (in the form of fullerene-like structure or nanotube), and at least one metal nanoparticle, uses thereof as a catalyst, (e.g. photocatalysis) and processes for its preparation.

  4. Effect of cobalt ferrite (CoFe2O4) nanoparticles on the growth and development of Lycopersicon lycopersicum (tomato plants).

    PubMed

    López-Moreno, Martha L; Avilés, Leany Lugo; Pérez, Nitza Guzmán; Irizarry, Bianca Álamo; Perales, Oscar; Cedeno-Mattei, Yarilyn; Román, Félix

    2016-04-15

    Nanoparticles (NPs) have been synthetized and studied to be incorporated in many industrial and medical applications in recent decades. Due to their different physical and chemical properties compared with bulk materials, researchers are focused to understand their interactions with the surroundings. Living organisms such as plants are exposed to these materials and they are able to tolerate different concentrations and types of NPs. Cobalt ferrite (CoFe2O4) NPs are being studied for their application in medical sciences because of their high coercivity, anisotropy, and large magnetostriction. These properties are desirable in magnetic resonance imaging, drug delivery, and cell labeling. This study is aimed to explore the tolerance of Solanum lycopersicum L. (tomato) plants to CoFe2O4 NPs. Tomato plants were grown in hydroponic media amended with CoFe2O4 nanoparticles in a range from 0 to 1000mgL(-1). Exposure to CoFe2O4 NPs did not affect germination and growth of plants. Uptake of Fe and Co inside plant tissues increased as CoFe2O4 nanoparticle concentration was increased in the media. Mg uptake in plant leaves reached its maximum level of 4.9mgg(-1) DW (dry weight) at 125mgL(-1) of CoFe2O4 NPs exposure and decreased at high CoFe2O4 NPs concentrations. Similar pattern was observed for Ca uptake in leaves where the maximum concentration found was 10mgg(-1) DW at 125mgL(-1) of CoFe2O4 NPs exposure. Mn uptake in plant leaves was higher at 62.5mgL(-1) of CoFe2O4 NPs compared with 125 and 250mgL(-1) treatments. Catalase activity in tomato roots and leaves decreased in plants exposed to CoFe2O4 NPs. Tomato plants were able to tolerate CoFe2O4 NPs concentrations up to 1000mgL(-1) without visible toxicity symptoms. Macronutrient uptake in plants was affected when plants were exposed to 250, 500 and 1000mgL(-1) of CoFe2O4 NPs.

  5. Preparation and characterization of bioactive glass nanoparticles prepared by sol-gel for biomedical applications

    NASA Astrophysics Data System (ADS)

    Luz, Gisela M.; Mano, João F.

    2011-12-01

    Bioactive glass nanoparticles (BG-NPs), based on both ternary (SiO2-CaO-P2O5) and binary (SiO2-CaO) systems, were prepared via an optimized sol-gel method. The pH of preparation and the effect of heat treatment temperature were evaluated, as well as the effect of suppressing P in the bioactivity ability of the materials. The morphology and composition of the BG-NPs were studied using FTIR, XRD and SEM. The bioactive character of these materials was accessed in vitro by analyzing the ability for apatite formation onto the surface after being immersed in simulated body fluid (SBF). XRD, EDX and SEM were used to confirm the bioactivity of the materials. The BG-NP effect on cell metabolic activity was assessed by seeding L929 cells with their leachables, proving the non-cytotoxicity of the materials. Finally the most bioactive BG-NPs developed (ternary system prepared at pH 11.5 and treated at 700 °C) were successfully combined with chitosan in the production of biomimetic nanocomposite osteoconductive membranes that could have the potential to be used in guided tissue regeneration.

  6. Fluorescence of silicon nanoparticles prepared by nanosecond pulsed laser

    SciTech Connect

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

    2014-03-15

    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.

  7. Preparation of proton conducting membranes containing bifunctional titania nanoparticles

    NASA Astrophysics Data System (ADS)

    Aslan, Ayşe; Bozkurt, Ayhan

    2013-07-01

    Throughout this work, the synthesis and characterization of novel proton conducting nanocomposite membranes including binary and ternary mixtures of sulfated nano-titania (TS), poly(vinyl alcohol) (PVA), and nitrilotri(methyl phosphonic acid) (NMPA) are discussed. The materials were produced by means of two different approaches where in the first, PVA and TS (10-15 nm) were admixed to form a binary system. The second method was the ternary nanocomposite membranes including PVA/TS/NMPA that were prepared at several compositions to get PVA-TS-(NMPA) x . The interaction of functional nano particles and NMPA in the host matrix was explored by FT-IR spectroscopy. The homogeneous distribution of bifunctional nanoparticles in the membrane was confirmed by SEM micrographs. The spectroscopic measurements and water/methanol uptake studies suggested a complexation between PVA and NMPA, which inhibited the leaching of the latter. The thermogravimetry analysis results verified that the presence of TS in the composite membranes suppressed the formation of phosphonic acid anhydrides up to 150 °C. The maximum proton conductivity has been measured for PVA-TS-(NMPA)3 as 0.003 S cm-1 at 150 °C.

  8. Colloidal Metal Nanoparticles Prepared by Laser Ablation and their Applications.

    PubMed

    Zhang, Jianming; Claverie, Jerome; Chaker, Mohamed; Ma, Dongling

    2017-02-05

    This review article highlights the recent advances of the synthesis and application of metal nanoparticles (NPs) fabricated via pulsed laser ablation in liquid (PLAL) phase and also introduces relevant NP formation mechanisms. Although wet-chemical approaches have been well established to synthesize colloidal metal NPs with various components and structures, some inherent drawbacks, such as reaction residuals and/or contaminations, largely limit some of their applications. The PLAL method has recently been developed as an alternative approach and received increasing attention for colloidal NP preparation, without involving complicated chemical reactions. In certain cases, by using PLAL, ligand-free and surface-clean NPs can be obtained and well dispersed in liquid, leading to the formation of a "surface-clean" NP dispersion. This unique feature renders PLAL-synthesised metal NPs attractive candidates for many interesting applications in catalysis, biology, sensing, and clean energy generation and storage. We conclude this review by proposing several interesting research directions and future challenges, from PLAL fabrication to applications. We hope this review can serve as a good reference and help with the further development of PLAL-NPs and their diverse applications.

  9. Synthesis, characterization and gas sensitivity investigation of Ni0.5Zn0.5Fe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Hamid Reza; Parish, Mohammad; Amiri, Gholam Reza; Bahraminejad, Behzad; Fatahian, Soheil

    2016-09-01

    Nickel zinc ferrite nanoparticles with diameters less than 20 nm were synthesized by co-precipitation method. The synthesized nanoparticles were annealed at 500 °C. Two types of samples (powder and disk) were prepared. The disk sample was prepared by pressing the powder sample. Magnetic and structural properties of the products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and alternating gradient-force magnetometer (AGFM). The X-ray analysis shows that the formation of the synthesized nickel zinc ferrite is spinell. The average crystalline size for nickel zinc ferrite powder was found around 19 nm (calculated by Debye-Scherer formula).The formation, size and the uniformity of the samples were determined by TEM. It was found that the size of nanoparticles should be around 18 nm from the SEM image. AGFM diagrams shows that the magnetization of the powder sample at the 9 kOe is 21.5 emu/g that of disk sample is 33 emu/g. Therefore, the magnetization was increased by pressing the nickel zinc ferrite nanoparticles. Sensor sensitivity of this disk ferrite is investigated in an isolated box. For this purpose, the samples are injected to this box and six gases (ethanol, methanol, chloroform, acetonitrile, acetone and methane) are exposed to the ferrite by a mechanical gate. The acetonitrile had the best sensitivity performance.

  10. Size-Controlled Pd Nanoparticle Catalysts Prepared by Galvanic Displacement into a Porous Si-Iron Oxide Nanoparticle Host.

    PubMed

    Kim, Taeho; Fu, Xin; Warther, David; Sailor, Michael J

    2017-02-21

    Porous silicon nanoparticles containing both Pd and iron oxide nanoparticles are prepared and studied as magnetically recoverable catalysts for organic reductions. The Pd nanoparticles are generated in situ by electroless deposition of Pd(NH3)4(2+), where the porous Si skeleton acts as both a template and as a reducing agent and the released ammonia ligands raise the local pH to exert control over the size of the Pd nanoparticles. The nanocomposites are characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen adsorption, X-ray diffraction, superconducting quantum interference device magnetization, and dynamic light scattering. The nanocomposite consists of a porous Si nanoparticle (150 nm mean diameter) containing ∼20 nm pores, uniformly decorated with a high loading of surfactant-free Pd nanoparticles (12 nm mean diameter) and superparamagnetic γ-Fe2O3 nanoparticles (∼7 nm mean diameter). The reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride is catalyzed by the nanocomposite, which is stable through the course of the reaction. Catalytic reduction of the organic dyes methylene blue and rhodamine B is also demonstrated. The conversion efficiency and catalytic activity are found to be superior to a commercial Pd/C catalyst compared under comparable reaction conditions. The composite catalyst can be recovered from the reaction mixture by applying an external magnetic field due to the existence of the superparamagnetic iron oxide nanoparticles in the construct. The recovered particles retain their catalytic activity.

  11. Structural and magnetic properties of NiZn-ferrite thin films prepared by radio frequency magnetron sputtering

    SciTech Connect

    Liu Yingli; Li Yuanxun; Zhang Huaiwu; Chen Daming; Mu Chunhong

    2011-04-01

    Polycrystalline NiZn-ferrite thin films were deposited on Si(100) substrate by rf magnetron sputtering, using targets with a nominal composition of Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}. The effects of substrate condition, sputtering pressure, and postannealing on the structure and magnetic properties of thin films have been investigated. Our results show that the preferred orientation of the NiZn spinel film changed from (311) to (400) with increasing the Ar pressure from 0.8 to 1.6 Pa, meanwhile, the grain size also increased. Atomic force microscopy analysis indicates that perfect surface morphology of the film can be obtained at a relatively lower sputtering pressure of 1.0 Pa. The relative percentage of residual oxygen increases significantly on a condition of lower sputtering pressure, and plays an important role in film structure due to the strong molecular adsorption tendency of oxygen on the film surface during the deposition process. A thin film with a typical thickness of 1 {mu}m, a saturation magnetization of 150 emu/cm{sup 3}, and a coercivity of 8.8 kA/m has been obtained after annealing at 800 deg. C, which has the potential application in magnetic integrated circuits.

  12. Preparation and characterization of polyol assisted ultrafine Cu-Ni-Mg-Ca mixed ferrite via co-precipitation method

    NASA Astrophysics Data System (ADS)

    Boobalan, T.; Pavithradevi, S.; Suriyanarayanan, N.; Manivel Raja, M.; Ranjith Kumar, E.

    2017-04-01

    Nanocrystalline spinel ferrite of composition Cu0.2Ni0.2Mg0.2Ca0.4Fe2O4 is synthesized by wet hydroxyl co-precipitation method in ethylene glycol as chelating agent and sodium hydroxide as precipitator at pH 8. Ethylene glycol is utilized as the medium which serves as the dissolvable and in addition a complexing specialist. The synthesized particles are annealed at various temperatures. Thermogravimetric investigation affirms that at 280 °C ethylene glycol is dissipated totally and stable phase arrangement happens over 680 °C. FTIR spectra of as synthesized and annealed at 1050 °C recorded between 400 cm-1 and 4000 cm-1. Structural characterizations of all the samples are carried out by X-ray diffraction (XRD) technique. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) affirm that the particles are spherical and cubic shape with the crystallite size of 12 nm to 32 nm. Magnetic measurements are performed utilizing vibrating sample magnetometer at room temperature.

  13. Dispersoid Distribution and Microstructure in Fe-Cr-Al Ferritic Oxide Dispersion-Strengthened Alloy Prepared by Friction Consolidation

    SciTech Connect

    Catalini, David; Kaoumi, Djamel; Reynolds, Anthony; Grant, Glenn J.

    2015-07-09

    INCOLOY® MA956 is a ferritic Oxide Dispersion Strengthened (ODS) alloy. Three different oxides, Y4Al2O9, YAlO3 and Y3Al5O12, have been observed in this alloy. The oxide particle sizes range from just a few up to hundreds of nm and these particles are responsible of the high temperature mechanical strength of this alloy. Mechanically alloyed MA956 powder was consolidated via Friction Consolidation using three different processing conditions. As a result, three small compacts of low porosity were produced. The compacts exhibited a refined equiaxed grain structure with grain sizes smaller than 10 µm and the desired oxide dispersion.YAlO3 and Y3Al5O12 were identified in the compacts by Scanning Electron Microscopy (SEM), Electron Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD). The size distribution of precipitates above 50 nm showed a direct proportionality between average precipitate size and grain size. The total energy input during processing was correlated with the relative amount of each of the oxides in the disks: the higher the total processing energy input, the higher the relative amount of Y3Al5O12 precipitates. The elemental composition of the oxide precipitates was also probed individually by EDS showing an aluminum enrichment trend as precipitates grow in size.

  14. Fabrication and integrity test preparation of HIP-joined W and ferritic-martensitic steel mockups for fusion reactor development

    NASA Astrophysics Data System (ADS)

    Lee, Dong Won; Shin, Kyu In; Kim, Suk Kwon; Jin, Hyung Gon; Lee, Eo Hwak; Yoon, Jae Sung; Choi, Bo Guen; Moon, Se Youn; Hong, Bong Guen

    2014-10-01

    Tungsten (W) and ferritic-martensitic steel (FMS) as armor and structural materials, respectively, are the major candidates for plasma-facing components (PFCs) such as the blanket first wall (BFW) and the divertor, in a fusion reactor. In the present study, three W/FMS mockups were successfully fabricated using a hot isostatic pressing (HIP, 900 °C, 100 MPa, 1.5 hrs) with a following post-HIP heat treatment (PHHT, tempering, 750 °C, 70 MPa, 2 hrs), and the W/FMS joining method was developed based on the ITER BFW and the test blanket module (TBM) development project from 2004 to the present. Using a 10-MHz-frequency flat-type probe to ultrasonically test of the joint, we found no defects in the fabricated mockups. For confirmation of the joint integrity, a high heat flux test will be performed up to the thermal lifetime of the mockup under the proper test conditions. These conditions were determined through a preliminary analysis with conventional codes such as ANSYS-CFX for thermal-hydraulic conditions considering the test facility, the Korea heat load test facility with an electron beam (KoHLT-EB), and its water coolant system at the Korea Atomic Energy Research Institute (KAERI).

  15. Magnetic and microwave absorbing properties of Co2+ substituted nickel-zinc ferrites with the emphasis on initial permeability studies

    NASA Astrophysics Data System (ADS)

    Ghodake, J. S.; Kambale, Rahul C.; Shinde, T. J.; Maskar, P. K.; Suryavanshi, S. S.

    2016-03-01

    Nanocrystalline Co2+ substituted Zn0.35Ni0.60-xCoxFe2.05O4 (Where x=0.0, 0.1, 0.2, 0.3 and 0.4) system have been synthesized by citrate-nitrate combustion route. X-ray diffraction study shows the formation of single phase cubic spinel structure without any impurity phases. Morphological observation shows agglomerated grains with different shapes and sizes which is the typical characteristics of magnetic nanoparticles prepared by combustion route. The saturation magnetization of cobalt substituted Ni-Zn ferrites is found to be higher than that of pure Ni-Zn ferrite. The coercivity and retentivity of cobalt substituted Ni-Zn ferrite increases with the increasing cobalt content. Initial permeability and loss factor have been studied as the function of composition and frequency. The real (μ‧) and imaginary (μ‧‧) part of initial permeability of cobalt substituted Ni-Zn ferrites decreases while its loss factor increases with the increasing cobalt content. In the lower frequency region the imaginary part of initial permeability (μ‧‧) of all samples is found to be decreasing rapidly with increasing frequency. The microwave absorption properties of cobalt substituted Ni-Zn ferrites were also investigated; all samples exhibit the absorption in the frequency range 2.3-2.5 GHz. Thus, the prepared materials can be used as a rubber composite microwave absorber and may be useful in RADAR application.

  16. Methods for Preparing Nanoparticle-Containing Thermoplastic Composite Laminates

    NASA Technical Reports Server (NTRS)

    Gruber, Mark B. (Inventor); Jensen, Brian J. (Inventor); Cano, Roberto J. (Inventor)

    2016-01-01

    High quality thermoplastic composites and composite laminates containing nanoparticles and/or nanofibers, and methods of producing such composites and laminates are disclosed. The composites comprise a thermoplastic polymer and a plurality of nanoparticles, and may include a fibrous structural reinforcement. The composite laminates are formed from a plurality of nanoparticle-containing composite layers and may be fused to one another via an automated process.

  17. Preparation and in vitro evaluation of hydrophilic fenretinide nanoparticles.

    PubMed

    Ledet, Grace A; Graves, Richard A; Glotser, Elena Y; Mandal, Tarun K; Bostanian, Levon A

    2015-02-20

    Fenretinide is an effective anti-cancer drug with high in vitro cytotoxicity and low in vivo systemic toxicity. In clinical trials, fenretinide has shown poor therapeutic efficacy following oral administration - attributed to its low bioavailability and solubility. The long term goal of this project is to develop a formulation for the oral delivery of fenretinide. The purpose of this part of the study was to prepare and characterize hydrophilic nanoparticle formulations of fenretinide. Three different ratios of polyvinyl pyrrolidone (PVP) to fenretinide were used, namely, 3:1, 4:1, and 5:1. Both drug and polymer were dissolved in a mixture of methanol and dichloromethane (2:23 v/v). Rotary evaporation was used to remove the solvents, and, following reconstitution with water, a high pressure homogenizer was used to form nanoparticles. The particle size and polydispersity index were measured before and after lyophilization. The formulations were studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray powder diffraction (XRPD). The effectiveness of the formulations was assessed by release studies and Caco-2 cell permeability assays. As the PVP content increased, the recovered particle size following lyophilization became more consistent with the pre-lyophilization particle size, especially for those formulations with less lactose. The DSC scans of the formulations did not show any fenretinide melting endotherms, indicating that the drug was either present in an amorphous form in the formulation or that a solid solution of the drug in PVP had formed. For the release studies, the highest drug release among the formulations was 249.2±35.5ng/mL for the formulation with 4:1 polymer-to-drug. When the permeability of the formulations was evaluated in a Caco-2 cell model, the mean normalized flux for each treatment group was significantly higher (p<0.05) from the fenretinide control. The formulation containing 4:1 polymer

  18. Ultrasonic cavitation induced water in vegetable oil emulsion droplets--a simple and easy technique to synthesize manganese zinc ferrite nanocrystals with improved magnetization.

    PubMed

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

    2012-05-01

    In the present investigation, synthesis of manganese zinc ferrite (Mn(0.5)Zn(0.5)Fe(2)O(4)) 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 of the ferrite, it was subjected to heat treatment at 300 °C for 3h. Both the as-prepared and heat treated ferrites have been characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), TGA/DTA, transmission electron microscopy (TEM) and energy dispersion X-ray spectroscopy (EDS) techniques. As-prepared ferrite is of 20 nm, whereas the heat treated ferrite shows the size of 33 nm. In addition, magnetic properties of the as-prepared as well as the heat treated ferrites have also been carried out and the results of which show that the spontaneous magnetization (σ(s)) of the heat treated sample (24.1 emu/g) is significantly higher than that of the as-synthesized sample (1.81 emu/g). The key features of this method are avoiding (a) the cumbersome conditions that exist in the conventional methods; (b) usage of necessary additive components (stabilizers or surfactants, precipitants) and (c) calcination requirements. In addition, rapeseed oil as an oil phase has been used for the first time, replacing the toxic and troublesome organic nonpolar solvents. As a whole, this simple straightforward sonochemical approach results in more phase pure system with improved magnetization.

  19. Jingle-bell-shaped ferrite hollow sphere with a noble metal core: Simple synthesis and their magnetic and antibacterial properties

    SciTech Connect

    Li Siheng; Wang Enbo Tian Chungui; Mao Baodong; Kang Zhenhui; Li Qiuyu; Sun Guoying

    2008-07-15

    In this paper, a simple strategy is developed for rational fabrication of a class of jingle-bell-shaped hollow structured nanomaterials marked as Ag(MFe{sub 2}O{sub 4}) (M=Ni, Co, Mg, Zn), consisting of ferrite hollow shells and metal nanoparticle cores, using highly uniform colloidal Ag(C) microspheres as template. The final composites were obtained by direct adsorption of metal cations Fe{sup 3+} and M{sup 2+} on the surface of the Ag(C) spheres followed by calcination process to remove the middle carbon shell and transform the metal ions into pure phase ferrites. The as-prepared composites were characterized by X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray analysis (EDX), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectroscopy and SQUID magnetometer. The results showed that the composites possess the magnetic property of the ferrite shell and the optical together with antibacterial property of the Ag core. - Graphical abstract: MFe{sub 2}O{sub 4} (M=Ni, Co, Mg, Zn) hollow spheres with a noble metal nanoparticle core were successfully prepared by using colloidal metal(C) core-shell spheres as templates with no need of surface modification. The shell thickness and magnetic properties of the ferrite hollow spheres could be controlled by varying the synthetic parameters.

  20. Preparation and characterization of DNA block copolymer assemblies loaded with nanoparticles.

    PubMed

    Chen, Xi-Jun; Hickey, Robert J; Park, So-Jung

    2013-01-01

    We have recently developed a universal procedure to functionalize inorganic nanoparticles with a dense layer of DNA through the self-assembly of DNA block copolymers and nanoparticles. This functionalization strategy allows one to combine the useful physical properties of inorganic nanoparticle with the enhanced DNA binding properties that originate from the high surface DNA density. In particular, the hybrid nanostructures exhibit orders of magnitude higher binding constants than regular DNA strands. This chapter presents a detailed protocol for the preparation and characterization of DNA block copolymer assemblies loaded with nanoparticles.

  1. Preparation and characterization of graphene oxide encapsulated gold nanoparticles.

    PubMed

    Yun, Yong Ju; Song, Ki-Bong

    2013-11-01

    We present a simple approach for the fabrication of graphene oxide-encapsulated gold nanoparticles using graphene oxide sheet-wrapping via electrostatic self-assembly. By mixing bovine serum albumin molecule-functionalized gold nanoparticles with graphene oxide dispersion, positively charged bovine serum albumin/gold nanoparticles easily assembled with negatively charged graphene oxide sheets through electrostatic interaction. Transmittance electron microscopy, scanning electron microscopy, atomic force microscopy, and Raman spectroscopy were used to confirm the encapsulation of graphene oxide on gold nanoparticles. Interestingly, graphene oxide sheets wrapping mainly occurs along the main body of single or a few gold nanoparticles. Additionally, by measuring the ultraviolet-visible spectroscopy spectrum, we found that the surface plasmon resonances band of the graphene oxide-encapsulated gold nanoparticles was found to become red-shifted compared to that of pristine gold nanoparticles, whereas similar to that of bovine serum albumin-coated gold nanoparticles. These results indicating that most of graphene oxide-encapsulated gold nanoparticles have good monodispersity and spherical shape. These resulting materials may potentially serve as a platform for plasmon resonance electron transfer spectroscopy or a probe for low level biosensing.

  2. Characterization and Dramatic Variations of the Magnetic Properties of Cu-DOPED Nanometric Co-Ferrite

    NASA Astrophysics Data System (ADS)

    Ahmed, M. A.; Mansour, S. F.; Abdo, M. A.

    2013-03-01

    Structure and magnetic properties of Co1-xCuxFe2O4 were investigated. Cobalt ferrite has been synthesized by double sintering ceramic technique. X-ray Diffraction (XRD) analysis and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 38 - 46 ± 3nm which is a good result for this method of preparation. The magnetic susceptibility was studied at different temperature as a function of magnetic field intensities. The room temperature hysteresis loop was performed for the present samples in the field intensity of 108kOe using VSM. The parameters of X-ray density (dx) and apparent density (da) increases with increasing Cu+2 concentrations in the prepared samples.

  3. Synthesis, Characterization and Microwave Absorption Properties of Polyaniline/Er-Doped Strontium Ferrite Nanocomposite.

    PubMed

    Luo, Juhua; Wang, Eryong; Xu, Yang

    2016-06-01

    Er-doped strontium ferrite nanopowders (SrEr0.3Fe11.7O19) were prepared by the sol-gel method, and then their composites of PANI/SrEr0.3Fe11.7O19 with 10 wt% and 20 wt% ferrite were prepared by an in-situ polymerization process. The characterization of obtained samples was accomplished by XRD, FT-IR, TEM, VSM, and vector network analyzer techniques. A successful conjugation of ferrite nanoparticles with polyaniline could be indicated by XRD and FT-IR analysis. TEM confirmed the formation of polyaniline packed on strontium ferrite surface. Magnetization measurements showed the substituted Er3+ of Fe3+ on basis site enhanced the magnetic property notably and the content of polyaniline also influenced the magnetic property prominently. PANI/SrEr0.3Fe11.7O19 possessed the best absorption property with the optimum matching thickness of 3 mm in the frequency of 2-18 GHz. The value of the maximum RL was -42.0 dB at 12.0 GHz with the 5.5 GHz bandwidth.

  4. Hollow nanoparticles of metal oxides and sulfides: fast preparation via laser ablation in liquid.

    PubMed

    Niu, K Y; Yang, J; Kulinich, S A; Sun, J; Du, X W

    2010-11-16

    In this work, diverse hollow nanoparticles of metal oxides and sulfides were prepared by simply laser ablating metal targets in properly chosen liquids. The Kirkendall voiding and the selective heating with an infrared laser were shown to work as two independent mechanisms for the formation of such hollow nanoparticles in only one- or two-step synthesis approaches. One of the prepared materials, ZnS hollow nanoparticles, showed high performance in gas sensing. The simple, fast, inexpensive technique that is proposed demonstrates very promising perspectives.

  5. Preparation and luminescent properties of GdOF:Ce, Tb nanoparticles and their transparent PMMA nanocomposites

    NASA Astrophysics Data System (ADS)

    Cai, Wen; Wang, Aiwu; Fu, Li; Hu, Jie; Rao, Tingke; Wang, Junqing; Zhong, Jiasong; Xiang, Weidong

    2015-05-01

    GdOF:Ce, Tb nanoparticles and their poly (methyl methacrylate) (PMMA) nanocomposites have been successfully prepared by a thermolysis route and thermal polymerization of methyl methacrylate (MMA) monomer, respectively. The obtained nanoparticles and nanocomposites are characterized by XRD, EDS, TEM, FTIR, TGA, UV-Vis and PL spectrum. The as-synthesized transparent GdOF:Ce, Tb/PMMA nanocomposites exhibit green photoluminescence under the irradiation of 254 nm UV lamp due to the incorporation of luminescent GdOF:Ce, Tb nanoparticles into the PMMA matrix. The present route would provide a general strategy to prepare other functional nanocomposites.

  6. Preparation of Pt-Ru-Ni ternary nanoparticles by microemulsion and electrocatalytic activity for methanol oxidation

    SciTech Connect

    Zhang Xin . E-mail: xzhang@stu.edu.cn; Zhang Feng; Guan Renfeng; Chan, K.-Y.

    2007-02-15

    Ternary platinum-ruthenium-nickel nanoparticles are prepared by water-in-oil reverse microemulsions of water/Triton X-100/propanol-2/cyclohexane. Nanoparticles formed in the microemulsions are characterized by transmission electron microscopy (TEM), electron diffraction (ED), X-ray diffractometry (XRD), energy dispersive X-ray analysis (EDX). These resulting materials showed a homogenous alloy structure, the mono-dispersion and an average diameter of 2.6 {+-} 0.3 nm with a narrow particle size distribution. The composition and particle size of ternary Pt-Ru-Ni nanoparticles can be controlled by adjusting the initial metal salt solution and preparation conditions. Pt-Ru-Ni ternary metallic nanoparticles showed an enhanced catalytic activity towards methanol oxidation compared to Pt-Ru bimetallic nanoparticles.

  7. Polymeric nanoparticles containing diazepam: preparation, optimization, characterization, in-vitro drug release and release kinetic study

    NASA Astrophysics Data System (ADS)

    Bohrey, Sarvesh; Chourasiya, Vibha; Pandey, Archna

    2016-03-01

    Nanoparticles formulated from biodegradable polymers like poly(lactic-co-glycolic acid) (PLGA) are being extensively investigated as drug delivery systems due to their two important properties such as biocompatibility and controlled drug release characteristics. The aim of this work to formulated diazepam loaded PLGA nanoparticles by using emulsion solvent evaporation technique. Polyvinyl alcohol (PVA) is used as stabilizing agent. Diazepam is a benzodiazepine derivative drug, and widely used as an anticonvulsant in the treatment of various types of epilepsy, insomnia and anxiety. This work investigates the effects of some preparation variables on the size and shape of nanoparticles prepared by emulsion solvent evaporation method. These nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM). Zeta potential study was also performed to understand the surface charge of nanoparticles. The drug release from drug loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by various kinetic models. The results show that sonication time, polymer content, surfactant concentration, ratio of organic to aqueous phase volume, and the amount of drug have an important effect on the size of nanoparticles. Hopefully we produced spherical shape Diazepam loaded PLGA nanoparticles with a size range under 250 nm with zeta potential -23.3 mV. The in vitro drug release analysis shows sustained release of drug from nanoparticles and follow Korsmeyer-Peppas model.

  8. Sustainable synthesis of monodispersed spinel nano-ferrites

    EPA Science Inventory

    A sustainable approach for the synthesis of various monodispersed spinel ferrite nanoparticles has been developed that occurs at water-toluene interface under both conventional and microwave hydrothermal conditions. This general synthesis procedure utilizes readily available and ...

  9. Gold core@silver semishell Janus nanoparticles prepared by interfacial etching

    NASA Astrophysics Data System (ADS)

    Chen, Limei; Deming, Christopher P.; Peng, Yi; Hu, Peiguang; Stofan, Jake; Chen, Shaowei

    2016-07-01

    Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold cores, as manifested in transmission electron microscopy, UV-vis absorption, and X-ray photoelectron spectroscopy measurements. Interestingly, the Au@Ag semishell Janus nanoparticles exhibited enhanced electrocatalytic activity in oxygen reduction reactions, as compared to their Au@Ag and Ag@Au core-shell counterparts, likely due to a synergistic effect between the gold cores and silver semishells that optimized oxygen binding to the nanoparticle surface.Gold core@silver semishell Janus nanoparticles were prepared by chemical etching of Au@Ag core-shell nanoparticles at the air/water interface. Au@Ag core-shell nanoparticles were synthesized by chemical deposition of a silver shell onto gold seed colloids followed by the self-assembly of 1-dodecanethiol onto the nanoparticle surface. The nanoparticles then formed a monolayer on the water surface of a Langmuir-Blodgett trough, and part of the silver shell was selectively etched away by the mixture of hydrogen peroxide and ammonia in the water subphase, where the etching was limited to the side of the nanoparticles that was in direct contact with water. The resulting Janus nanoparticles exhibited an asymmetrical distribution of silver on the surface of the gold

  10. Gold nanoparticles: preparation, functionalisation and applications in biochemistry and immunochemistry

    NASA Astrophysics Data System (ADS)

    Dykman, Lev A.; Bogatyrev, Vladimir A.

    2007-02-01

    The review summarises data on the synthesis and functionalisation of gold nanoparticles and their applications in biological investigations. Particular attention is given to applications of colloidal gold in solid-phase assays, immunoassay and studies of biologically active compounds by vibrational spectroscopy. A special section deals with the use of gold nanoparticles as antigen carriers in immunisation.

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

    PubMed

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

    2014-08-01

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

  12. Electrical and optical properties of nickel ferrite/polyaniline nanocomposite

    PubMed Central

    Khairy, M.; Gouda, M.E.

    2014-01-01

    Polyaniline–NiFe2O4 nanocomposites (PANI–NiFe2O4) with different contents of NiFe2O4 (2.5, 5 and 50 wt%) were prepared via in situ chemical oxidation polymerization, while the nanoparticles nickel ferrite were synthesized by sol–gel method. The prepared samples were characterized using some techniques such as Fourier transforms infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). Moreover, the electrical conductivity and optical properties of the nanocomposites were investigated. Pure (PANI) and the composites containing 2.5 and 5 wt% NiFe2O4 showed amorphous structures, while the one with 50 wt% NiFe2O4 showed a spinel crystalline structure. The SEM images of the composites showed different aggregations for the different nickel ferrite contents. FTIR spectra revealed to the formation of some interactions between the PANI macromolecule and the NiFe2O4 nanoparticles, while the thermal analyses indicated an increase in the composites stability for samples with higher NiFe2O4 nanoparticles contents. The electrical conductivity of PANI–NiFe2O4 nanocomposite was found to increase with the rise in NiFe2O4 nanoparticle content, probably due to the polaron/bipolaron formation. The optical absorption experiments illustrate direct transition with an energy band gap of Eg = 1.0 for PANI–NiFe2O4 nanocomposite. PMID:26199745

  13. Preparation of graphene-Ag nanoparticles hybrids and their SERS activities

    NASA Astrophysics Data System (ADS)

    Wang, Xinyu; Wang, Ning; Gong, Tiancheng; Zhu, Yong; Zhang, Jie

    2016-11-01

    Surface-enhanced Raman scattering (SERS) substrates based on graphene and Ag nanoparticles hybrid structures with low cost, high uniformity were prepared by a standard process of immobilization of silver nanoparticles with 3-aminopropyltrimethoxysilane (APTMS). Thermal annealing was used for removing residual APTMS and adjusting the morphology of silver nanoparticles, and the effectiveness of this method was verified experimentally. The influence of annealing temperature, dipping duration, and APTMS volume on the distribution of Ag nanoparticles and Raman enhancement was investigated experimentally and analyzed in detail. Our samples were prepared under the preparation conditions of 10% ν/ν APTMS, dipping time of 48 h, annealing temperature of 450 °C, duration of 30 min, and Ar flow rate of 40 sccm. SERS activities with enhancement of 107 and relative standard deviation of <20% were observed using rhodamine 6G (R6G) as probe molecule with a concentration of 10-6 M and 10-7 M.

  14. A moderate method for preparation DMSA coated Fe3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Song, L. N.; Gu, N.; Zhang, Y.

    2017-01-01

    A moderate way to prepare water soluble magnetic Fe3O4 nanoparticles has been developed. Firstly, oleic acid coated Fe3O4 is prepared by coprecipitation. Second, oleic acid were replaced by 2,3-dimercaptosuccinnic acid (DMSA) to prepare DMSA/Fe3O4 in the mixed solution of n-hexane and acetone. After dialysis and filtration the DMSA/Fe3O4 can be transferred into distilled water to form stable Fe3O4 nanoparticle solutions. The TEM images indicated that the particles had spherical shape and the nanoparticles were found to be 12 nm with a relatively narrow size distribution with the hydrodynamic size of 30 nm. And the result of VSM shows that DMSA/Fe3O4 nanoparticles have a saturation magnetization of 31 emu/g. The IR spectra indicated that the iron oxide was located by carboxyl matrix.

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

    PubMed

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

    2006-04-19

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

  16. A simple improved desolvation method for the rapid preparation of albumin nanoparticles.

    PubMed

    Jahanban-Esfahlan, Ali; Dastmalchi, Siavoush; Davaran, Soodabeh

    2016-10-01

    The current study tried to establish a simple and fast method for the preparation of BSA and HSA nanoparticles, based on an improved desolvation procedure under the aspect of a controllable particle size around 100nm for drug delivery applications. The Procedure used for the nanoparticles preparation was simplified by using a designed apparatus for controlling the addition of ethanol and it was used instead of conventional tubing pump which enabled the preparation of nanoparticles under defined conditions. By using EDC as cross-linker instead of glutharaldehyde, the time of nanoparticles preparation procedure was reduced to 3h. Several factors of the preparation process, such as the volume of the albumin solution, desolvating agent volume, the amount of cross-linker, the presence of salts and protein concentration were evaluated. Nanoparticles with smaller size were obtained under experimental conditions without the presence of salts or the use of buffers, 250mg of protein/4ml water, 5mg cross-linker, the addition of 4 and 8ml ethanol by using the designed apparatus to the HSA and BSA solution, respectively. By using this improved method, BSA and HSA nanoparticles of the size around 100nm and polydispersity below 0.2 were obtained.

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

    SciTech Connect

    Kapoor, S. . E-mail: sudhirk@apsara.barc.ernet.in; Belapurkar, A.D.; Mittal, J.P.; Mukherjee, T. . E-mail: mukherji@magnum.barc.ernet.in

    2005-10-06

    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.

  18. Low-temperature preparation of highly conductive thin films from acrylic acid-stabilized silver nanoparticles prepared through ligand exchange.

    PubMed

    Vo, Duc Quy; Shin, Eun Woo; Kim, Jae-Seong; Kim, Sunwook

    2010-11-16

    The preparation of AcA-stabilized Ag nanoparticles and its application to make highly conductive thin films are reported. The AcA-stabilized Ag nanoparticles were prepared through a ligand exchange of original oleylamine (OLA)-coated Ag nanoparticles with acrylic acid (AcA), which acted as both an antisolvent and a modifying ligand during the ligand exchange process. Efficiencies of the ligand exchange as well as the properties of Ag nanoparticles were analyzed using various techniques including TEM, FT-IR, XPS, TGA, and UV-vis methods. The thin films were fabricated by annealing spin-coated AcA-stabilized Ag nanoparticles. Further, the effects of annealing temperature, time, and film thickness on both the film morphology and electrical conductivity have been investigated. In this work, due to the low boiling temperature of stabilizer (AcA) and adjustment of annealing conditions, high electrical conductivity was obtained for the Ag thin films. For example, when annealing at 175 °C for 30 min, a 70 nm thick film showed a maximum electrical conductivity of 1.12 × 10(5) S cm(-1). A conductive layer on a flexible polymer substrate (e.g., PET) sheet has been successfully prepared by annealing a spin-coated film at 140 °C for 30 min. The combined advantages of long-term stability of the AcA-stabilized Ag nanoparticles, low annealing temperature, and high conductivity of the prepared thin films make this relatively simple method attractive for applications in flexible electronics.

  19. Copper nanoparticles functionalized PE: Preparation, characterization and magnetic properties

    NASA Astrophysics Data System (ADS)

    Reznickova, A.; Orendac, M.; Kolska, Z.; Cizmar, E.; Dendisova, M.; Svorcik, V.

    2016-12-01

    We report grafting of copper nanoparticles (CuNP) on plasma activated high density polyethylene (HDPE) via dithiol interlayer pointing out to the structural and magnetic properties of those composites. The as-synthesized Cu nanoparticles have been characterized by high-resolution transmission electron microscopy (HRTEM/TEM) and UV-vis spectroscopy. Properties of pristine PE and their plasma treated counterparts were studied by different experimental techniques: X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, energy dispersive X-ray spectroscopy (EDS), zeta potential, electron spin resonance (ESR) and SQUID magnetometry. From TEM and HRTEM analyses, it is found that the size of high purity Cu nanoparticles is (12.2 ± 5.2) nm. It was determined that in the CuNPs, the copper atoms are arranged mostly in the (111) and (200) planes. Absorption in UV-vis region by these nanoparticles is ranging from 570 to 670 nm. EDS revealed that after 1 h of grafting are Cu nanoparticles homogeneously distributed over the whole surface and after 24 h of grafting Cu nanoparticles tend to aggregate slightly. The combined investigation of magnetic properties using ESR spectrometry and SQUID magnetometry confirmed the presence of copper nanoparticles anchored on PE substrate and indicated ferromagnetic interactions.

  20. Synthesis, Characterization, and Microwave Absorption Properties of Reduced Graphene Oxide/Strontium Ferrite/Polyaniline Nanocomposites.

    PubMed

    Luo, Juhua; Shen, Pan; Yao, Wei; Jiang, Cuifeng; Xu, Jianguang

    2016-12-01

    Strontium ferrite nanoparticles were prepared by a coprecipitation method, and reduced graphene oxide/strontium ferrite/polyaniline (R-GO/SF/PANI) ternary nanocomposites were prepared by in situ polymerization method. The morphology, structure, and magnetic properties of the ternary nanocomposites were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), TEM, Raman, and VSM. The microwave-absorbing properties of the composites were measured by a vector network analyzer. The XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. TEM photographs reveal that strontium ferrite nanoparticles are uniformly dispersed on the surfaces of R-GO sheets. The R-GO/SF/PANI nanocomposite exhibited the best absorption property with the optimum matching thickness of 1.5 mm in the frequency of 2-18 GHz. The value of the maximum RL was -45.00 dB at 16.08 GHz with the 5.48-GHz bandwidth. The excellent absorption properties of R-GO/SF/PANI nanocomposites indicated their great potential as microwave-absorbing materials.

  1. Synthesis, Characterization, and Microwave Absorption Properties of Reduced Graphene Oxide/Strontium Ferrite/Polyaniline Nanocomposites

    NASA Astrophysics Data System (ADS)

    Luo, Juhua; Shen, Pan; Yao, Wei; Jiang, Cuifeng; Xu, Jianguang

    2016-03-01

    Strontium ferrite nanoparticles were prepared by a coprecipitation method, and reduced graphene oxide/strontium ferrite/polyaniline (R-GO/SF/PANI) ternary nanocomposites were prepared by in situ polymerization method. The morphology, structure, and magnetic properties of the ternary nanocomposites were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), TEM, Raman, and VSM. The microwave-absorbing properties of the composites were measured by a vector network analyzer. The XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. TEM photographs reveal that strontium ferrite nanoparticles are uniformly dispersed on the surfaces of R-GO sheets. The R-GO/SF/PANI nanocomposite exhibited the best absorption property with the optimum matching thickness of 1.5 mm in the frequency of 2-18 GHz. The value of the maximum RL was -45.00 dB at 16.08 GHz with the 5.48-GHz bandwidth. The excellent absorption properties of R-GO/SF/PANI nanocomposites indicated their great potential as microwave-absorbing materials.

  2. 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...

  3. In situ synthesis of cobalt ferrite nanoparticle/polymer hybrid from a mixed Fe-Co methacrylate for magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Hayashi, Koichiro; Maeda, Kazuki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

    2012-09-01

    Hyperthermic CoFe2O4 nanoparticle (CFO NP)/polymer hybrids were synthesized by hydrolysis-condensation from a complex of Co and Fe possessing methacrylate ligands. Single-crystal analysis revealed that the complex consisted of two Co and four Fe metal atoms coordinated by methacrylate and 2-methoxyethoxy groups. The complex was copolymerized with 2-hydroxyethyl methacrylate (HEMA) and the resulting copolymer was then hydrolyzed to form a CFO NP/copolymer of poly(methacrylate) and poly(2-hydroxyethyl methacrylate) hybrid. Copolymerization with HEMA enhanced the stability of the hybrid in water. The size and magnetic properties of CFO in the hybrid were controlled by adjusting the hydrolysis conditions. Moreover, the hybrid generated heat under an alternating current magnetic field; its exothermal properties depended on the magnetic properties of the hybrid, the strength of the applied field, and the CFO NP content in the agar phantom matrix.

  4. Self-assembly and embedding of nanoparticles by in situ reduced graphene for preparation of a 3D graphene/nanoparticle aerogel.

    PubMed

    Chen, Wufeng; Li, Sirong; Chen, Chunhua; Yan, Lifeng

    2011-12-15

    A 3D graphene architecture can be prepared via an in situ self-assembly of graphene prepared by a mild chemical reduction. Fe(3) O(4) nanoparticles are homogeneously dispersed into graphene oxide (GO) aqueous suspension and a 3D magnetic graphene/Fe(3) O(4) aerogel is prepared during the reduction of GO to graphene. This provides a general method to prepare 3D graphene/nanoparticle composites for a wide range of applications including catalysis and energy conversion.

  5. Preparation and characterization of carvacrol loaded polyhydroxybutyrate nanoparticles by nanoprecipitation and dialysis methods.

    PubMed

    Shakeri, Fatemeh; Shakeri, Shahryar; Hojjatoleslami, Mohammad

    2014-04-01

    In this investigation, preparation of carvacrol loaded polyhydroxybutyrate (PHB) nanoparticles was performed by nanoprecipitation and dialysis methods. PHB particles were obtained by nanoprecipitation method without and with low concentration of Tween 80 or pluronic as surfactant. Nano- and micro-sized particles were formed with trimodal distribution and large aggregates. Size and distribution of nanoparticles were decreased when concentration of Tween 80 was increased to 1% (v/v) in water as polar phase. PHB nanoparticles had narrow size (157 nm) with monomodal distribution. Nanoparticles, which were prepared by dialysis method had 140 nm in diameter with monomodal distribution. Carvacrol was used as a lipophilic drug and entrapped in optimized nanoparticles formulation by nanoprecipitation and dialysis methods. Entrapment efficacy was 21% and 11%, respectively. Morphology of PHB nanoparticles was spherical. The results of kinetic release study showed that carvacrol was released for at least 3 days. Release kinetic parameters showed a simple Fickian diffusion behavior for both formulations. Carvacrol loaded PHB nanoparticles had good dispersion into the agar medium and antimicrobial activity against Escherichia coli. This study describes the 1st work on loading of carvacrol into the PHB nanoparticles by nanoprecipitation and dialysis methods.

  6. Chitosan Nanoparticles Prepared by Ionotropic Gelation: An Overview of Recent Advances.

    PubMed

    Desai, Kashappa Goud

    2016-01-01

    The objective of this review is to summarize recent advances in chitosan nanoparticles prepared by ionotropic gelation. Significant progress has occurred in this area since the method was first reported. The gelation technique has been improved through a number of creative methodological modifications. Ionotropic gelation via electrospraying and spinning disc processing produces nanoparticles with a more uniform size distribution. Large-scale manufacturing of the nanoparticles can be achieved with the latter approach. Hydrophobic and hydrophilic drugs can be simultaneously encapsulated with high efficiency by emulsification followed by ionic gelation. The turbulent mixing approach facilitates nanoparticle formation at a relatively high polymer concentration (5 mg/mL). The technique can be easily tuned to achieve the desired polymer/surface modifications (e.g., blending, coating, and surface conjugation). Using factorial-design-based approaches, optimal conditions for nanoparticle formation can be determined with a minimum number of experiments. New insights have been gained into the mechanism of chitosan-tripolyphosphate nanoparticle formation. Chitosan nanoparticles prepared by ionotropic gelation tend to aggregate/agglomerate in unfavorable environments. Factors influencing this phenomenon and strategies that can be adopted to minimize the instability are discussed. Ionically cross-linked nanoparticles based on native chitosan and modified chitosan have shown excellent efficacy for controlled and targeted drug-delivery applications.

  7. Preparation of magnetic mesoporous silica nanoparticles as a multifunctional platform for potential drug delivery and hyperthermia

    PubMed Central

    Yu, Xia; Zhu, Yufang

    2016-01-01

    Abstract We report the preparation of magnetic mesoporous silica (MMS) nanoparticles with the potential multifunctionality of drug delivery and magnetic hyperthermia. Carbon-encapsulated magnetic colloidal nanoparticles (MCN@C) were used to coat mesoporous silica shells for the formation of the core-shell structured MMS nanoparticles (MCN@C/mSiO2), and the rattle-type structured MMS nanoparticles (MCN/mSiO2) were obtained after the removal of the carbon layers from MCN@C/mSiO2 nanoparticles. The morphology, structure, magnetic hyperthermia ability, drug release behavior, in vitro cytotoxicity and cellular uptake of MMS nanoparticles were investigated. The results revealed that the MCN@C/mSiO2 and MCN/mSiO2 nanoparticles had spherical morphology and average particle sizes of 390 and 320 nm, respectively. The MCN@C/mSiO2 nanoparticles exhibited higher magnetic hyperthermia ability compared to the MCN/mSiO2 nanoparticles, but the MCN/mSiO2 nanoparticles had higher drug loading capacity. Both MCN@C/mSiO2 and MCN/mSiO2 nanoparticles had similar drug release behavior with pH-controlled release and temperature-accelerated release. Furthermore, the MCN@C/mSiO2 and MCN/mSiO2 nanoparticles showed low cytotoxicity and could be internalized into HeLa cells. Therefore, the MCN@C/mSiO2 and MCN/mSiO2 nanoparticles would be promising for the combination of drug delivery and magnetic hyperthermia treatment in cancer therapy. PMID:27877873

  8. Heat generation ability in AC magnetic field of nano MgFe2O4-based ferrite powder prepared by bead milling

    NASA Astrophysics Data System (ADS)

    Hirazawa, Hideyuki; Aono, Hiromichi; Naohara, Takashi; Maehara, Tsunehiro; Sato, Mitsunori; Watanabe, Yuji

    2011-03-01

    Nanosized MgFe2O4-based ferrite powder having heat generation ability in an AC magnetic field was prepared by bead milling and studied for thermal coagulation therapy applications. The crystal size and the particle size significantly decreased by bead milling. The heat generation ability in an AC magnetic field improved with the milling time, i.e. a decrease in crystal size. However, the heat generation ability decreased for excessively milled samples with crystal sizes of less than 5.5 nm. The highest heat ability (ΔT=34 °C) in the AC magnetic field (370 kHz, 1.77 kA/m) was obtained for fine MgFe2O4 powder having a ca. 6 nm crystal size (the samples were milled for 6-8 h using 0.1 mm ϕ beads). The heat generation of the samples was closely related to hysteresis loss, a B-H magnetic property. The reason for the high heat generation properties of the samples milled for 6-8 h using 0.1 mm ϕ beads was ascribed to the increase in hysteresis loss by the formation of a single domain. Moreover, the improvement in heating ability was obtained by calcination of the bead-milled sample at low temperature. In this case, the maximum heat generation (ΔT=41 °C) ability was obtained for a ca. 11 nm crystal size sample was prepared by crystal growth during the sample calcination. On the other hand, the ΔT value for Mg0.5Ca0.5Fe2O4 was synthesized using a reverse precipitation method decreased by bead milling.

  9. Characterization of soy protein nanoparticles prepared by high shear microfluidization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soy protein nanoparticles were produced with a microfluidizer and characterized in terms of particle size, size distribution, morphology, rheological properties, and aggregate structure. Three stages of structure breakdown were observed when the soy protein dispersion was passed through the microflu...

  10. Synthesize and characterization of a novel anticorrosive cobalt ferrite nanoparticles dispersed in silica matrix (CoFe2O4-SiO2) to improve the corrosion protection performance of epoxy coating

    NASA Astrophysics Data System (ADS)

    Gharagozlou, M.; Ramezanzadeh, B.; Baradaran, Z.

    2016-07-01

    This study aimed at studying the effect of an anticorrosive nickel ferrite nanoparticle dispersed in silica matrix (NiFe2O4-SiO2) on the corrosion protection properties of steel substrate. NiFe2O4 and NiFe2O4-SiO2 nanopigments were synthesized and then characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscope (TEM). Then, 1 wt.% of nanopigments was dispersed in an epoxy coating and the resultant nanocomposites were applied on the steel substrates. The corrosion inhibition effects of nanopigments were tested by an electrochemical impedance spectroscopy (EIS) and salt spray test. Results revealed that dispersing nickel ferrite nanoparticles in a silica matrix (NiFe2O4-SiO2) resulted in the enhancement of the nanopigment dispersion in the epoxy coating matrix. Inclusion of 1 wt.% of NiFe2O4-SiO2 nanopigment into the epoxy coating enhanced its corrosion protection properties before and after scratching.

  11. Synthesis, characterization, in vitro and in vivo studies of dextrin-coated zinc-iron ferrite nanoparticles (Zn0.5Fe0.5Fe2O4) as contrast agent in MRI

    NASA Astrophysics Data System (ADS)

    Zare, T.; Lotfi, M.; Heli, H.; Azarpira, N.; Mehdizadeh, A. R.; Sattarahmady, N.; Abdollah-dizavandi, M. R.; Heidari, M.

    2015-09-01

    Iron oxide nanoparticles, such as ferrites, offer some attractive possibilities in biomedicine, especially in MRI applications. The objective of this study is to investigate the effectiveness of dextrin-coated zinc-iron ferrite nanoparticles (IFNPs) as an MRI contrast agent in in vivo and in vitro media. IFNPs were synthesized by an aqueous precipitation method in the presence of dextrin. An agarose phantom with different concentrations of dextrin-coated IFNPs was performed on a 1.5-T MRI. For in vivo MRI studies, implanted melanoma tumors in mice were immediately scanned after intra-tumoral injection of dextrin-coated IFNPs. Microscopic studies showed that the average diameter of dextrin-coated IFNPs was 12 ± 2.4 nm and the saturation magnetization for IFNPs was 31.5 emu g-1; r 1 and r 2 relaxivities of these ultrasmall superparamagnetic IFNPs in agarose phantom were obtained as 0.99 and 17.4 mmol L-1 s-1, respectively. The relaxivity measurements revealed that the dextrin-coated IFNPs can serve as a negative contrast agent. In vivo MRI showed that the dextrin-coated IFNPs can be used for tumor detection. The dextrin-coated IFNPs were suggested to be applied for lymph node and targeted imaging.

  12. Ferrite thin films for microwave applications

    NASA Astrophysics Data System (ADS)

    Zaquine, I.; Benazizi, H.; Mage, J. C.

    1988-11-01

    This paper describes the preparation and the properties of thin (a few micron-thick) ferrite films for microwave applications. The films were deposited by RF sputtering from a single ferrite target on two different 4-in-thick substrates, silicon and alumina, both bare and metallized. The as-deposited films were amorphous, requiring careful annealing in oxygen atmosphere. The optimum annealing temperature was determined by obtaining the highest possible magnetization for each ferrite. The conditions of microwave measurements are described together with the results.

  13. Water-Soluble Spinel Ferrites by a Modified Polyol Process as Contrast Agents in MRI

    SciTech Connect

    Basina, Georgia; Tzitzios, Vasilis; Niarchos, Dimitris; Li Wanfeng; Khurshid, Hafsa; Hadjipanayis, George; Mao Hui; Hadjipanayis, Costas

    2010-12-02

    Magnetic nanoparticles have recently been very attractive for biomedical applications. In this study, we have synthesized ferrite nanoparticles for application as contrast agents in MRI experiments. Fe{sub 3}O{sub 4} and MnFe{sub 2}O{sub 4} spinel ferrites with a mean size of 11-12 nm, were prepared by a modified polyol route in commercially available polyethylene glycol with molecular weight 600 (PEG-600). The reaction takes place in the presence of water soluble and non-toxic tri-block copolymer known as Pluronic registered F-127 (PEO{sub 100}-PPO{sub 65}-PEO{sub 100}). The nanoparticles have saturation magnetization values of 52 and 68 emu/g for MnFe{sub 2}O{sub 4} and Fe{sub 3}O{sub 4}, respectively. Both the Fe{sub 3}O{sub 4}, and MnFe{sub 2}O{sub 4} nanoparticles make stable solutions in water known as ferrofluids. Preliminary data demonstrated the capability of these nanoparticles to induce imaging contrast in T{sub 2} weighted MRI experiments, making these materials suitable for biomedical applications such as medical MRI.

  14. Microbial mediated preparation, characterization and optimization of gold nanoparticles.

    PubMed

    Barabadi, Hamed; Honary, Soheila; Ebrahimi, Pouneh; Mohammadi, Milad Ali; Alizadeh, Ahad; Naghibi, Farzaneh

    2014-01-01

    The need for eco-friendly and cost effective methods for nanoparticles synthesis is developing interest in biological approaches which are free from the use of toxic chemicals as byproducts. This study aimed to biosynthesize and optimize the size of gold nanoparticles which produced by biotechnological method using Penicillium crustosum isolated from soil. Initially, Penicillium crustosum was grown in fluid czapek dox broth on shaker at 28 °C and 200 rpm for ten days and then the supernatant was separated from the mycelia to convert AuCl₄ solution into gold nanoparticles. The synthesized nanoparticles in the optimum conditions were formed with fairly well-defined dimensions and good monodispersity. The characterizations were done by using different methods (UV-Visible Spectroscopy, Fluorescence, FT-IR, AFM (Atomic Force Microscopy) and DLS (Dynamic Light Scattering). The bioconversion was optimized by Box-Behnken experimental design. The results show that the effective factors in this process were concentration of AuCl₄, pH of medium and temperature of shaker incubator. The R(2) value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations.

  15. Preparation of gold nanoparticle dimers via streptavidin-induced interlinking

    NASA Astrophysics Data System (ADS)

    Zon, Vera B.; Sachsenhauser, Matthias; Rant, Ulrich

    2013-10-01

    There is great interest in establishing efficient means of organizing nanoparticles into complex structures, especially in fields like nano-optical devices. One of the demonstrated routes uses biomolecular scaffolds, like the streptavidin-biotin system, to deterministically separate and structure particle complexes. However, controlled formation of streptavidin-linked nanoparticle dimers or trimers is challenging, and large aggregates are often formed under conditions that are difficult to regulate. Here, we studied the aggregates and interlinking kinetics of biotin-functionalized 20 nm gold nanoparticles in the presence of the interlinking protein, streptavidin. We found two different protein-linker concentration regions where small stable particle aggregates are formed: when the protein and nanoparticle concentrations are similar and when the protein to nanoparticle concentration ratio exceeds intermediate concentrations (10:1-100:1) that promote precipitation of large aggregates. We attribute this behavior to the limited availability of free-linker molecules and the limited availability of free ligand (biotin) on the particle surface for low and high protein concentrations, respectively. Furthermore, we show that the product can be additionally enriched up to 25 % through either centrifugation in sucrose or size-exclusion chromatography. These results provide additional understanding into the assembly of ligand-functionalized nanoparticles with water-soluble linkers and provide a facile way to produce well-defined small aggregates for potential use in, for instance, surface-enhanced spectroscopy.

  16. Preparation of monodisperse and size-controlled poly(ethylene glycol) hydrogel nanoparticles using liposome templates.

    PubMed

    An, Se Yong; Bui, Minh-Phuong Ngoc; Nam, Yun Jung; Han, Kwi Nam; Li, Cheng Ai; Choo, Jaebum; Lee, Eun Kyu; Katoh, Shigeo; Kumada, Yoichi; Seong, Gi Hun

    2009-03-01

    Liposomes were used as templates to prepare size-controlled and monodisperse poly(ethylene glycol) (PEG) hydrogel nanoparticles. The procedure for the preparation of PEG nanoparticles using liposomes consists of encapsulation of photopolymerizable PEG hydrogel solution into the cavity of the liposomes, extrusion through a membrane with a specific pore size, and photopolymerization of the contents inside the liposomes by UV irradiation. The size distributions of the prepared particles were 1.32+/-0.16 microm (12%), 450+/-62 nm (14%), and 94+/-12 nm (13%) after extrusion through membrane filters with pore sizes of 1 microm, 400 nm, and 100 nm, respectively. With this approach, it is also possible to modify the surface of the hydrogel nanoparticles with various functional groups in a one-step procedure. To functionalize the surface of a PEG nanoparticle, methoxy poly(ethylene glycol)-aldehyde was added as copolymer to the hydrogel-forming components and aldehyde-functionalized PEG nanoparticles could be obtained easily by UV-induced photopolymerization, following conjugation with poly-L-lysine-FITC through amine-aldehyde coupling. The prepared PEG particles showed strong fluorescence from FITC on the edge of the particles using confocal microscopy. The immobilization of biomaterials such as enzymes in hydrogel particles could be performed with loading beta-galactosidases during the hydration step for liposome preparation without additional procedures. The resorufin produced by applying resorufin beta-D-galactopyranoside as the substrate showed the fluorescence under the confocal microscopy.

  17. Preparation of cobalt nanoparticles from polymorphic bacterial templates: A novel platform for biocatalysis.

    PubMed

    Jang, Eunjin; Shim, Hyun-Woo; Ryu, Bum Han; An, Deu Rae; Yoo, Wan Ki; Kim, Kyeong Kyu; Kim, Dong-Wan; Kim, T Doohun

    2015-11-01

    Nanoparticles have gathered significant research attention as materials for enzyme immobilization due to their advantageous properties such as low diffusion rates, ease of manipulation, and large surface areas. Here, polymorphic cobalt nanoparticles of varied sizes and shapes were prepared using Micrococcus lylae, Bacillus subtilis, Escherichia coli, Paracoccus sp., and Haloarcula vallismortis as bacterial templates. Furthermore, nine lipases/carboxylesterases were successfully immobilized on these cobalt nanoparticles. Especially, immobilized forms of Est-Y29, LmH, and Sm23 were characterized in more detail for potential industrial applications. Immobilization of enzymes onto cobalt oxide nanoparticles prepared from polymorphic bacterial templates may have potential for efficient hydrolysis on an industrial-scale, with several advantages such as high retention of enzymatic activity, increased stability, and strong reusability.

  18. Preparation and characterization of ketoprofen loaded eudragit RS polymeric nanoparticles for controlled release

    NASA Astrophysics Data System (ADS)

    Anh, Nguyen Tuan; Chi, Nguyen T.; Khai Tran, T.; Tuyen Dao, T. P.; Nhan Le, N. T.; Mau Chien, Dang; Hoai, Nguyen To

    2012-12-01

    Nanospheres containing ketoprofen (Keto) and polymer eudragit RS were prepared using an emulsion solvent evaporation method. The ultrasonic probe (VCX500, vibracell) was used as a tool to disperse oil phase into aqueous phase leading to water/oil emulsion. Nanoparticles were successfully prepared and their morphologies and diameters were confirmed by transmission electron microscope (TEM) and dynamic light scattering (DLS), respectively. The result showed that particles were spherical with submicron size. The particle size was dependent on the RS concentration, emulsification tools and the types of organic solvents. For the encapsulation ability, Keto-loaded RS nanoparticle showed 9.8% of Keto in nanoparticle, which was evaluated by high-performance liquid chromatography (HPLC). Moreover, the drug release behavior of Keto-loaded eudragit RS nanoparticle was also investigated in vitro at pH 7.4 and compared to referential profenid.

  19. Metal nanoparticles (other than gold or silver) prepared using plant extracts for medical applications

    NASA Astrophysics Data System (ADS)

    Pasca, Roxana-Diana; Santa, Szabolcs; Racz, Levente Zsolt; Racz, Csaba Pal

    2016-12-01

    There are many modalities to prepare metal nanoparticles, but the reducing of the metal ions with plant extracts is one of the most promising because it is considerate less toxic for the environment, suitable for the use of those nanoparticles in vivo and not very expensive. Various metal ions have been already studied such as: cobalt, copper, iron, platinum, palladium, zinc, indium, manganese and mercury and the number of plant extracts used is continuously increasing. The prepared systems were characterized afterwards with a great number of methods of investigation: both spectroscopic (especially UV-Vis spectroscopy) and microscopic (in principal, electron microscopy-TEM) methods. The applications of the metal nanoparticles obtained are diverse and not completely known, but the medical applications of such nanoparticles occupy a central place, due to their nontoxic components, but some diverse industrial applications do not have to be forgotten.

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

    NASA Astrophysics Data System (ADS)

    Lari, L.; Dudkiewicz, A.

    2014-06-01

    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.

  1. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection

    NASA Astrophysics Data System (ADS)

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-03-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection.

  2. Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: Structure, Preparation and Application

    PubMed Central

    Naseri, Neda; Valizadeh, Hadi; Zakeri-Milani, Parvin

    2015-01-01

    Lipid nanoparticles (LNPs) have attracted special interest during last few decades. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are two major types of Lipid-based nanoparticles. SLNs were developed to overcome the limitations of other colloidal carriers, such as emulsions, liposomes and polymeric nanoparticles because they have advantages like good release profile and targeted drug delivery with excellent physical stability. In the next generation of the lipid nanoparticle, NLCs are modified SLNs which improve the stability and capacity loading. Three structural models of NLCs have been proposed. These LNPs have potential applications in drug delivery field, research, cosmetics, clinical medicine, etc. This article focuses on features, structure and innovation of LNPs and presents a wide discussion about preparation methods, advantages, disadvantages and applications of LNPs by focusing on SLNs and NLCs. PMID:26504751

  3. Preparation of low-crystalline apatite nanoparticles and their coating onto quartz substrates.

    PubMed

    Kawashita, Masakazu; Taninai, Koji; Li, Zhixia; Ishikawa, Kunio; Yoshida, Yasuhiro

    2012-06-01

    We prepared low-crystalline apatite nanoparticles and coated them onto a surface of a Au/Cr-plated quartz substrate by the electrophoretic deposition (EPD) method or by using a self-assembled monolayer of 11-mercaptoundecanoic acid (SAM method). Low-crystalline apatite nanoparticles around 10 nm in size with extremely low contents of undesirable residual products were obtained by adding (NH(4))(2)HPO(4) aqueous droplets into a modified synthetic body fluid solution that contained Ca(CH(3)COO)(2). The apatite nanoparticles were successfully coated by either the EPD method or the SAM method; the nanoparticle coating achieved by the SAM method was more uniform than that achieved by the EPD method. The present SAM method is expected to be a promising technique for obtaining a quartz substrate coated with apatite nanoparticles, which can be used as a quartz crystal microbalance device.

  4. Preparation of a novel silk microfiber covered by AgCl nanoparticles with antimicrobial activity.

    PubMed

    Xie, Qifan; Xu, Zongpu; Hu, Binhui; He, Xiuling; Zhu, Liangjun

    2017-03-01

    We prepared silk fibroin microfibers in which silver chloride (AgCl) nanoparticles were dispersed, by sequential dipping of microfibers obtained using alkaline hydrolysis in alternating solutions of silver nitrate and potassium chloride. Scanning and transmission electron microscopy showed an increase in nanoparticle size and quantity with increase in dipping cycles and solution concentration, but ultrasound irradiation did not affect nanoparticle formation. The presence of cubic AgCl crystals was confirmed by energy dispersive X-ray spectroscopy and X-ray diffractometry. Differential scanning calorimetry and Fourier transform infrared spectroscopy revealed that the nanoparticles do not affect the microfiber properties. The growth of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria was inhibited by microfiber covered with AgCl nanoparticles. This antimicrobial activity allows to use microfiber as a reinforced or surface additive biomaterial. Microsc. Res. Tech. 80:272-279, 2017. © 2016 Wiley Periodicals, Inc.

  5. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection.

    PubMed

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-01-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection.

  6. Effects of Microemulsion Preparation Conditions on Drug Encapsulation Efficiency of PLGA Nanoparticles

    NASA Astrophysics Data System (ADS)

    Ng, Set Hui; Ooi, Ing Hong

    2011-12-01

    Emulsion solvent evaporation technique is widely used to prepare nanoparticles of many organic polymer drug carriers. The mechanism of nanoparticle generation by this technique involves oil-in-water (O/W) microemulsion formation followed by solvent evaporation. Various microemulsion preparation conditions can affect the encapsulation efficiency of drug in the nanoparticulate carrier. In this study, emulsifying speed, emulsifying temperature, and organic-to-aqueous phase ratio were varied and the resulting encapsulation efficiency of a model drug in Poly(Lactide-co-Glycolide) (PLGA) nanoparticles was determined. The organic phase containing PLGA and a model drug dissolved in chloroform was first dispersed in an aqueous solution containing 0.5 %(w/v) Poly(vinyl alcohol) (PVA), which was then homogenized at high speeds. The resulting O/W microemulsion was subsequently subjected to stirring at room temperature for four hours during which the solvent diffused and evaporated gradually. The fine white suspension was centrifuged and freeze-dried. The model drug loading in the PLGA nanoparticles was determined using UV spectrophotometry. Results showed that the encapsulation efficiency of a model drug, salicylic acid, ranged from 8.5% to 17% depending on the microemulsion preparation conditions. Under the same temperature (15 °C) and homogenization speed (19000 rpm) conditions studied, a relatively high organic-to-aqueous phase ratio (1:5) provided salicylic acid loaded PLGA nanoparticles with significantly higher drug encapsulation efficiency. In addition, under all microemulsion preparation conditions, PLGA nanoparticles obtained after solvent evaporation and freeze drying were spherical and aggregation between the nanoparticles was not observed under a high power microscope. This indicates that PLGA nanoparticles with desirable amount of drug and with anticipated size and shape can be realized by controlling emulsification process conditions.

  7. Preparation, Characterization and Manipulation of Conjugates between Gold Nanoparticles and DNA

    PubMed Central

    Eidelshtein, Gennady; Fattal, Moran; Avishai, Gavriel; Kempinski, Benjamin; Giannini, Clelia; Kotlyar, Alexander

    2016-01-01

    Here we described the preparation and characterization by atomic force microscopy of dumbbell-shaped conjugates between 450 bp double-stranded DNA polymer, poly(dG)-poly(dC), and 5 nm gold nanoparticles (GNPs). We have demonstrated that the size of the nanoparticles in the conjugates can be increased in a controlled fashion. Application of the conjugates for measuring the electrical conductivity of DNA is discussed. PMID:28335294

  8. Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method

    NASA Astrophysics Data System (ADS)

    Bobadilla, L. F.; García, C.; Delgado, J. J.; Sanz, O.; Romero-Sarria, F.; Centeno, M. A.; Odriozola, J. A.

    2012-11-01

    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.

  9. Preparation of New Reducing Agent for the Synthesis of Silver Nanoparticles

    NASA Astrophysics Data System (ADS)

    Manivel, P.; Sivashanmugan, K.; Viswanathan, C.; Mangalaraj, D.

    2011-07-01

    2,3,5,6-Tetrakis-(morpholinomethyl)hydroquinone (TMMH) is used first time to prepare spherical silver nanoparticles by the reduction of Silver nitrate (AgNO3) in water-ethanol medium without using any stabilizing and capping agent. The compound (TMMH) was isolated by aminomethylation of hydroquinone with morpholine. The resultant compound characterized by 1H NMR, 13C NMR and FT-IR Spectra for conformation studies. The ratio of AgNO3 and compound (TMMH) played role in controlling the particle size and shape of silver nanoparticles. The formation of the silver nanoparticles was observed in UV-Vis absorption spectroscopy.

  10. Magnetic properties of bimetallic Au/Co nanoparticles prepared by thermal laser treatment

    NASA Astrophysics Data System (ADS)

    Sosunov, A. V.; Spivak, L. V.

    2016-07-01

    The irradiation of metallic films by a nanosecond pulsed laser leads to a self-assembly of nanoparticle arrays. This method has been used to prepare bimetallic Au/Co nanoparticles on a SiO2 substrate. The microstructure and morphology of the bimetallic nanoparticles have been investigated using scanning electron microscopy and transmission electron microscopy. It has been shown that the bimetallic nanoparticles have a hemispherical shape with a single-crystal structure and an average size of ~50 nm. The magnetic properties of these nanoparticles have been examined using a vibrating-sample magnetometer in the transverse and longitudinal directions. It has been found that the direction of the magnetization of the bimetallic nanoparticles lies in the plane of the substrate, and the coercive forces in the transverse and longitudinal directions differ by 25%. The use of the vibrating-sample magnetometer method makes it possible to investigate the differences in the magnetic saturations and the coercive forces of an array of bimetallic nanoparticles on a large surface area. The performed investigations have demonstrated that the anisotropic nanomagnetic materials with the desired magnetic orientation can be easily and quickly prepared by means of thermal laser treatment.

  11. Preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels.

    PubMed

    Im, Hee-Jung; Lee, Byung Cheol; Yeon, Jei-Won

    2013-11-01

    Ag nanoparticles, used for halogen (especially iodine) adsorption and an evaluation of halogen behavior, were embedded in synthesized inorganic-organic hybrid gels. In particular, an irradiation method using an electron beam plays a part in introducing Ag nanoparticles to the organofunctionalized silica gels from AgNO3 solutions in a simple way at atmospheric pressure and room temperature. For preparation of the Ag nanoparticle-embedded inorganic-organic hybrid gels, ligands of ethylenediamine (NH2CH2CH2NH-, TMSen) and mercapto (HS-) functionalized three-dimensional porous SiO2 sol-gels were first synthesized through hydrolysis and condensation reactions, and Ag nanoparticles were then embedded into the ethylenediamine- and mercapto-anchored silica gels each, through electron-beam irradiation. The addition of ligands yielded larger average pore sizes than the absence of any ligand. Moreover, the ethylenediamine ligand led to looser structures and better access of the Ag nanoparticles to the ethylenediamine-anchored gel. As a result, more Ag nanoparticles were introduced into the ethylenediamine-anchored gel. The preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels are discussed in detail.

  12. Preparation of magnetic Fe3O4@SiO2 nanoparticles for immobilization of lipase.

    PubMed

    Liu, Wei; Zhou, Fang; Zhang, Xiao-Yun; Li, Yue; Wang, Xiang-Yu; Xu, Xi-Ming; Zhang, Ye-Wang

    2014-04-01

    Magnetic Fe3O4 nanoparticles were prepared with coprecipitatation method and covered with SiO2 to form the core-shell Fe3O4@SiO2 nanoparticles. Then the nanoparticles were modified with glutaradehyde for functionalization of the surface to aldehyde groups. The transmission electron microscopy confirmed the core-shell structure and revealed that the size of the nanoparticles was around 10 nm. It was observed that the lipase was immobilized on the nanoparticles successfully from the Fourier transform infrared spectra. The immobilized lipase on Fe3O4@SiO2 nanoparticles was characterized and compared to free enzyme. There are no significant differences observed in the optimal pH, temperature and Km before and after immobilization. However, the immobilized lipase displayed higher relative activity in the range of pH from 7.0 to 9.5. Compare with the free enzyme, the immobilized one showed higher thermal stability at temperature range from 30 to 70 degrees C, especially at high temperature. The relative activity of immobilized enzyme was 5.8 fold of the free lipase at 70 degrees C after 10 h incubation. Thus, the prepared lipase was proved to have the advantages like higher relative activity, better stability, broader pH range and easy to recovery. These results suggest that immobilization of lipase on Fe3O4@SiO2 nanoparticles has the potential industrial applications.

  13. Preparation of gold nanoparticles and determination of their particles size via different methods

    SciTech Connect

    Iqbal, Muhammad; Usanase, Gisele; Oulmi, Kafia; Aberkane, Fairouz; Bendaikha, Tahar; Fessi, Hatem; Zine, Nadia; Agusti, Géraldine; Errachid, El-Salhi; Elaissari, Abdelhamid

    2016-07-15

    Graphical abstract: Preparation of gold nanoparticles via NaBH{sub 4} reduction method, and determination of their particle size, size distribution and morphology by using different techniques. - Highlights: • Gold nanoparticles were synthesized by NaBH{sub 4} reduction method. • Excess of reducing agent leads to tendency of aggregation. • The particle size, size distribution and morphology were investigated. • Particle size was determined both experimentally as well as theoretically. - Abstract: Gold nanoparticles have been used in various applications covering both electronics, biosensors, in vivo biomedical imaging and in vitro biomedical diagnosis. As a general requirement, gold nanoparticles should be prepared in large scale, easy to be functionalized by chemical compound of by specific ligands or biomolecules. In this study, gold nanoparticles were prepared by using different concentrations of reducing agent (NaBH{sub 4}) in various formulations and their effect on the particle size, size distribution and morphology was investigated. Moreover, special attention has been dedicated to comparison of particles size measured by various techniques, such as, light scattering, transmission electron microscopy, UV spectrum using standard curve and particles size calculated by using Mie theory and UV spectrum of gold nanoparticles dispersion. Particle size determined by various techniques can be correlated for monodispersed particles and excess of reducing agent leads to increase in the particle size.

  14. Synthesis and preparation of biocompatible and pH-responsive cyclodextrin-based nanoparticle

    NASA Astrophysics Data System (ADS)

    Hu, Xiaohong; Chen, Shangneng; Gong, Xiao; Gao, Ziyu; Wang, Xin; Chen, Pin

    2017-03-01

    As a temporarily protective reaction for active hydrogen group, acetylation is reversible and responsive to low pH value. According to the reaction, pH-sensitive β-cyclodextrin (β-CD) was synthesized in the first step of our research. During the synthesis, the acetal groups including linear acetal (LA) groups and cyclic acetal (CA) groups were successfully modified onto β-CD. Particularly, the structural details of acetalated β-CD (Ac-β-CD) were greatly influenced by reaction time. Furthermore, in respect to water solubility, Ac-β-CDs exhibited different pH response properties due to their different structure. In the second step, Ac-β-CD1 nanoparticles were prepared by a single oil-in-water (O/W) emulsion technique using a biocompatible emulsifier, gelatin. Meanwhile, gelatin was absorbed onto the surface of nanoparticle, which was confirmed by FTIR spectra. The formed nanoparticles showed monodispersion and nearly spherical morphology. In order to obtain optimal preparing conditions, the effects of preparative parameters such as gelatin concentration, Ac-β-CD concentration, and water/oil ratio on properties including diameters and zeta potential as well as gelatin content were investigated. Moreover, the pH response properties of nanoparticle were characterized by transparency of nanoparticle solution. Finally, in vitro cell culture confirmed that Ac-β-CD nanoparticle could support cell survival and enhance cell viability.

  15. Preparation and characterization of polymeric nanoparticles from Gadong starch

    NASA Astrophysics Data System (ADS)

    Sisika, Regina; Ahmad, Wan Yaacob Wan; Fazry, Shazrul; Lazim, Azwan Mat

    2015-09-01

    Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

  16. Preparation and characterization of polymeric nanoparticles from Gadong starch

    SciTech Connect

    Sisika, Regina; Ahmad, Wan Yaacob Wan; Lazim, Azwan Mat; Fazry, Shazrul

    2015-09-25

    Dioscorea hispida (Gadong tuber) was seldom used and forgotten as a food source due to their toxicity. In contrast to that, the Gadong tuber can be a source of polysaccharides which can be manipulated as an alternative source for industrial applications. This research reported on how to synthesize starch nanoparticles from Gadong tuber by using a simple acid hydrolysis process. The yield of starch nanoparticles obtained from seven days of acid hydrolysis was reduced to 13%. The X-ray diffraction measurements showed that the native Gadong starch particle is of the C-crystalline type, and that the synthesized nanoparticles showed an increase in crystallinity compared to the native particles. Transmission electron microscopy results demonstrated that the starch particle morphologies were either round or irregular shape, with diameters ranging from 96-110 nm.

  17. Predictive Toxicology of cobalt ferrite nanoparticles: comparative in-vitro study of different cellular models using methods of knowledge discovery from data

    PubMed Central

    2013-01-01

    Background Cobalt-ferrite nanoparticles (Co-Fe NPs) are attractive for nanotechnology-based therapies. Thus, exploring their effect on viability of seven different cell lines representing different organs of the human body is highly important. Methods The toxicological effects of Co-Fe NPs were studied by in-vitro exposure of A549 and NCIH441 cell-lines (lung), precision-cut lung slices from rat, HepG2 cell-line (liver), MDCK cell-line (kidney), Caco-2 TC7 cell-line (intestine), TK6 (lymphoblasts) and primary mouse dendritic-cells. Toxicity was examined following exposure to Co-Fe NPs in the concentration range of 0.05 -1.2 mM for 24 and 72 h, using Alamar blue, MTT and neutral red assays. Changes in oxidative stress were determined by a dichlorodihydrofluorescein diacetate based assay. Data analysis and predictive modeling of the obtained data sets were executed by employing methods of Knowledge Discovery from Data with emphasis on a decision tree model (J48). Results Different dose–response curves of cell viability were obtained for each of the seven cell lines upon exposure to Co-Fe NPs. Increase of oxidative stress was induced by Co-Fe NPs and found to be dependent on the cell type. A high linear correlation (R2=0.97) was found between the toxicity of Co-Fe NPs and the extent of ROS generation following their exposure to Co-Fe NPs. The algorithm we applied to model the observed toxicity belongs to a type of supervised classifier. The decision tree model yielded the following order with decrease of the ranking parameter: NP concentrations (as the most influencing parameter), cell type (possessing the following hierarchy of cell sensitivity towards viability decrease: TK6 > Lung slices > NCIH441 > Caco-2 = MDCK > A549 > HepG2 = Dendritic) and time of exposure, where the highest-ranking parameter (NP concentration) provides the highest information gain with respect to toxicity. The validity of the chosen decision tree model J48 was established by

  18. Magnetic field directed assembly of superstructures of ferrite-ferroelectric core-shell nanoparticles and studies on magneto-electric interactions

    SciTech Connect

    Srinivasan, G. Sreenivasulu, G.; Benoit, Crystal; Petrov, V. M.; Chavez, F.

    2015-05-07

    Composites of ferromagnetic and ferroelectric are of interest for studies on mechanical strain mediated magneto-electric (ME) interactions and for useful technologies. Here, we report on magnetic-field-assisted-assembly of barium titanate (BTO)-nickel ferrite (NFO) core-shell particles into linear chains and 2D/3D arrays and measurements of ME effects in such assemblies. First, we synthesized the core-shell nano-particles with 50–600 nm BTO and 10–200 nm NFO by chemical self-assembly by coating the ferroic particles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst via the “click” reaction. The core-shell structure was confirmed with electron microscopy and scanning probe microscopy. We obtained superstructure of the core-shell particles by subjecting them to a magnetic field gradient that exerts an attractive force on the particles and align them toward the regions of high field strengths. At low particle concentration, linear chains were formed and they evolved into 2D and 3D arrays at high particle concentrations. Magnetoelectric characterization on unassembled films and assembled arrays has been performed through measurements of low-frequency ME voltage coefficient (MEVC) by subjecting the sample to a bias magnetic field and an ac magnetic field. The MEVC is higher for field-assembled samples than for unassembled films and is found to be sensitive to field orientation with a higher MEVC for magnetic fields parallel to the array direction than for magnetic fields perpendicular to the array. A maximum MEVC of 20 mV/cm Oe, one of the highest reported for any bulk nanocomposite, is measured across the array thickness. A model is provided for ME coupling in the superstructures of BTO-NFO particulate composites. First, we estimated the MEVC for a free-standing BTO-NFO core-shell particle and then extended the model to include an array of linear chains of the particles. The theoretical estimates are in

  19. Magnetic field directed assembly of superstructures of ferrite-ferroelectric core-shell nanoparticles and studies on magneto-electric interactions

    NASA Astrophysics Data System (ADS)

    Srinivasan, G.; Sreenivasulu, G.; Benoit, Crystal; Petrov, V. M.; Chavez, F.

    2015-05-01

    Composites of ferromagnetic and ferroelectric are of interest for studies on mechanical strain mediated magneto-electric (ME) interactions and for useful technologies. Here, we report on magnetic-field-assisted-assembly of barium titanate (BTO)-nickel ferrite (NFO) core-shell particles into linear chains and 2D/3D arrays and measurements of ME effects in such assemblies. First, we synthesized the core-shell nano-particles with 50-600 nm BTO and 10-200 nm NFO by chemical self-assembly by coating the ferroic particles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst via the "click" reaction. The core-shell structure was confirmed with electron microscopy and scanning probe microscopy. We obtained superstructure of the core-shell particles by subjecting them to a magnetic field gradient that exerts an attractive force on the particles and align them toward the regions of high field strengths. At low particle concentration, linear chains were formed and they evolved into 2D and 3D arrays at high particle concentrations. Magnetoelectric characterization on unassembled films and assembled arrays has been performed through measurements of low-frequency ME voltage coefficient (MEVC) by subjecting the sample to a bias magnetic field and an ac magnetic field. The MEVC is higher for field-assembled samples than for unassembled films and is found to be sensitive to field orientation with a higher MEVC for magnetic fields parallel to the array direction than for magnetic fields perpendicular to the array. A maximum MEVC of 20 mV/cm Oe, one of the highest reported for any bulk nanocomposite, is measured across the array thickness. A model is provided for ME coupling in the superstructures of BTO-NFO particulate composites. First, we estimated the MEVC for a free-standing BTO-NFO core-shell particle and then extended the model to include an array of linear chains of the particles. The theoretical estimates are in qualitative

  20. Rapid magnetic solid-phase extraction based on monodisperse magnetic single-crystal ferrite nanoparticles for the determination of free fatty acid content in edible oils.

    PubMed

    Wei, Fang; Zhao, Qin; Lv, Xin; Dong, Xu-Yan; Feng, Yu-Qi; Chen, Hong

    2013-01-09

    This study proposes a rapid magnetic solid-phase extraction (MSPE) based on monodisperse magnetic single-crystal ferrite (Fe(3)O(4)) nanoparticles (NPs) for determining the quantities of eight free fatty acids (FFAs), including palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), linolenic acid (C18:3), arachidic acid (C20:0), eicosenoic acid (C20:1), and behenic acid (C22:0) in oil. The amine-functionalized mesoporous Fe(3)O(4) magnetic NPs were applied as a sorbent for MSPE of FFAs from oil samples in a process that is based on hydrophilic interaction. The extraction can be completed rapidly in a dispersive mode with the aid of vigorous vortex. Additional tedious processing steps such as centrifugation and evaporation of organic solvent were not necessary with this procedure. Furthermore, esterification of FFAs can be accomplished during the desorption procedure by using methanol/sulfuric acid (99:1, v/v) as the desorption solvent. Several parameters affecting the extraction efficiency were investigated, including the matrix solvent for extraction, the desorption solvent and desorption time, and the amount of sorbent and extraction time. The pretreatment process was rapid under optimal conditions, being accomplished within 15 min. When coupled with gas chromatography-flame ionization detection (GC-FID), a rapid, simple, and convenient MSPE-GC-FID method for the determination of FFAs in oil samples was established with a total analysis time within 25 min. The limits of detection for the target FFAs were found to be 7.22-26.26 ng/mL. Recoveries in oil samples were in the range of 81.33-117.75%, with RSDs of <6.4% (intraday) and <6.9% (interday). This method was applied successfully to the analysis of dynamic FFA formation in four types of edible oils subjected to an accelerated storage test. The simple, rapid, and cost-effective method developed in the current study offers a potential application for the extraction and

  1. Probing the interaction induced conformation transitions in acid phosphatase with cobalt ferrite nanoparticles: Relation to inhibition and bio-activity of Chlorella vulgaris acid phosphatase.

    PubMed

    Ahmad, Farooq; Zhou, Xing; Yao, Hongzhou; Zhou, Ying; Xu, Chao

    2016-09-01

    The present study explored the interaction and kinetics of cobalt ferrite nanoparticles (NPs) with acid phosphatase (ACP) by utilizing diverse range of spectroscopic techniques. The results corroborate, the CoFe2O4 NPs cause fluorescence quenching in ACP by static quenching mechanism. The negative values of van't Hoff thermodynamic expressions (ΔH=-0.3293Jmol(-1)K(-1) and ΔG=-3.960kJmol(-1)K(-1)) corroborate the spontaneity and exothermic nature of static quenching. The positive value of ΔS (13.2893Jmol(-1)K(-1)) corroborate that major contributors of higher and stronger binding affinity among CoFe2O4 NPs with ACP were electrostatic. In addition, FTIR, UV-CD, UV-vis spectroscopy and three dimensional fluorescence (3D) techniques confirmed that CoFe2O4 NPs binding induces microenvironment perturbations leading to secondary and tertiary conformation changes in ACP to a great extent. Furthermore, synchronous fluorescence spectroscopy (SFS) affirmed the comparatively significant changes in microenvironment around tryptophan (Trp) residue by CoFe2O4 NPs. The effect of CoFe2O4 NPs on the activation kinetics of ACP was further examined in Chlorella vulgaris. Apparent Michaelis constant (Km) values of 0.57 and 26.5mM with activation energy values of 0.538 and 3.428kJmol(-1) were determined without and with 200μM CoFe2O4 NPs. Apparent Vmax value of -7Umml(-1) corroborate that enzyme active sites were completely captured by the NPs leaving no space for the substrate. The results confirmed that CoFe2O4 NPs ceased the activity by unfolding of ACP enzyme. This suggests CoFe2O4 NPs perturbed the enzyme activity by transitions in conformation and hence the metabolic activity of ACP. This study provides the pavement for novel and simple approach of using sensitive biomarkers for sensing NPs in environment.

  2. Zinc ferrite nanoparticles activate IL-1b, NFKB1, CCL21 and NOS2 signaling to induce mitochondrial dependent intrinsic apoptotic pathway in WISH cells.

    PubMed

    Saquib, Quaiser; Al-Khedhairy, Abdulaziz A; Ahmad, Javed; Siddiqui, Maqsood A; Dwivedi, Sourabh; Khan, Shams T; Musarrat, Javed

    2013-12-01

    The present study has demonstrated the translocation of zinc ferrite nanoparticles (ZnFe2O4-NPs) into the cytoplasm of human amnion epithelial (WISH) cells, and the ensuing cytotoxicity and genetic damage. The results suggested that in situ NPs induced oxidative stress, alterations in cellular membrane and DNA strand breaks. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and neutral red uptake (NRU) cytotoxicity assays indicated 64.48 ± 1.6% and 50.73 ± 2.1% reduction in cell viability with 100 μg/ml of ZnFe2O4-NPs exposure. The treated WISH cells exhibited 1.2-fold higher ROS level with 0.9-fold decline in membrane potential (ΔΨm) and 7.4-fold higher DNA damage after 48h of ZnFe2O4-NPs treatment. Real-time PCR (qPCR) analysis of p53, CASP 3 (caspase-3), and bax genes revealed 5.3, 1.6, and 14.9-fold upregulation, and 0.18-fold down regulation of bcl 2 gene vis-à-vis untreated control. RT(2) Profiler™ PCR array data elucidated differential up-regulation of mRNA transcripts of IL-1b, NFKB1, NOS2 and CCL21 genes in the range of 1.5 to 3.7-folds. The flow cytometry based cell cycle analysis suggested the transfer of 15.2 ± 2.1% (p<0.01) population of ZnFe2O4-NPs (100 μg/ml) treated cells into apoptotic phase through intrinsic pathway. Over all, the data revealed the potential of ZnFe2O4-NPs to induce cellular and genetic toxicity in cells of placental origin. Thus, the significant ROS production, reduction in ΔΨm, DNA damage, and activation of genes linked to inflammation, oxidative stress, proliferation, DNA damage and repair could serve as the predictive toxicity and stress markers for ecotoxicological assessment of ZnFe2O4-NPs induced cellular and genetic damage.

  3. Binary-surfactant (Brij 35 + Tween 20) assisted preparation of highly dispersed Pt nanoparticles on carbon

    NASA Astrophysics Data System (ADS)

    Lim, Dong-Ha; Lu, Lianhai; Kim, Dong Baek; Choi, Dong-Hyeok; Park, Dal-Ryung; Lee, Ho-In

    2008-10-01

    Pt nanoparticles supported on Vulcan XC-72R, synthesized by a surfactant-stabilized colloidal method, exhibited excellent properties as anode catalyst for low-temperature fuel cell. The Pt/C catalyst prepared with binary-surfactant (Brij 35 + Tween 20) at 10 times CMC had an average particle size of 2.8 nm with quite a narrow distribution between 2 and 4 nm. Our preparation method resulted in complete reduction of Pt and full loading of Pt nanoparticles on the carbon. The home-made Pt/C catalyst showed higher EAS and better catalytic activity than a commercial Pt/C catalyst. The method used in this study provided an easy and reproducible procedure for the preparation of Pt nanoparticles supported on carbon.

  4. Preparation and characterization of platinum-ruthenium bimetallic nanoparticles using reverse microemulsions for fuel cell catalyst.

    PubMed

    Kim, Taeyoon; Kobayashi, Koichi; Nagai, Masayuki

    2007-01-01

    Platinum-ruthenium bimetallic nanoparticles are prepared by chemical reduction using sodium borohydride in reverse microemulsions of water/isooctane/Igepal CA-630/2-propanol for fuel cell catalysts. The prepared nanoparticles are characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive X-ray analysis. The average size and morphology of nanoparticles are dependent on the water volume fraction in reverse microemulsion system in the range of ca. 2-4 nm. The morphology of particles is related with the percolation behavior of water droplets in reverse microemulsions. By the pretreatment of water phase using a hydrochloric acid, the particles of a homogeneous solid solution state can be obtained. The CO stripping cyclovoltammetry and the electrochemical measurements compared with commercial catalyst show that the prepared particles have a high electrochemically active surface area and a stable and high catalytic activity for reformate gas oxidation.

  5. Preparation of Novel Europium Complex Doped Ag@SiO2 Nanoparticles with Intense Fluorescence.

    PubMed

    Liu, Bing; Yin, Dongguang; Song, Kailin; Yang, Juan Ou; Wang, Chengcheng; Wu, Minghong

    2015-01-01

    In this study, a new europium complex of 4,4'-bis (1",1",1",2",2",3",3"-heptafluoro-4",6"- hexanedion-6"-yl)-o-terpheny-Eu(3+)-4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid-(3-aminopropyl) trimethoxysilane (BHHT-Eu(3+)-DPPDA-APTMS) was prepared first. Then novel core-shell Ag@SiO2 nanoparticles with BHHT-Eu(3+)-DPPDA-APTMS doped in shell were synthesized by a facile water-in-oil microemulsion method. The properties of the prepared complex and nanoparticles, and the effect of metal enhanced fluorescence for the nanoparticles were investigated. The prepared nanopartilces exhibited intense fluorescence, uniform morphology and good water-solubility. The fluorescent intensities of silver core-present nanopartciles were significant higher than that of silver core-absent nanoparticles owing to the metal enhanced fluorescence of silver core. It is expectable that the as-prepared nanoparticles can serve as a potential fluorescent nanoprobe, applying in high sensitive biological and medical detections.

  6. Vancomycin loaded superparamagnetic MnFe2O4 nanoparticles coated with PEGylated chitosan to enhance antibacterial activity.

    PubMed

    Esmaeili, Akbar; Ghobadianpour, Sepideh

    2016-03-30

    Increasing prevalence of antibiotic-resistant and failed-treatment make more investigations to deal with these problems. Hence new therapeutic approaches for effective treatment are necessary. Ferrite superparamagnetic nanoparticles have potentially antibacterial activity. In this study we prepared MnFe2O4 superparamagnetic nanoparticles as core by precipitation method and used chitosan crosslinked by glutaraldehyde as shell, then modified with PEG to increase stability of particles against RES. Chitosan coating not only improves the properties of ferrit nanoparticles but also has antibacterial activity. FT-IR confirmed this surface modification; XRD and SEM were developed to demonstrate particle size approximately 25 nm and characteristics of crystal structure of these nanoparticles. Magnetic properties of nanoparticles were evaluated by VSM. Actual drug loading and releasing were examined by UV-vis spectroscopy method. We employed liquid broth dilution method to assessment antibacterial activity of nanoparticles against microorganisms. Significant antibacterial effect against gram negative bacteria was developed.

  7. Streptomycin-loaded PLGA-alginate nanoparticles: preparation, characterization, and assessment

    NASA Astrophysics Data System (ADS)

    Asadi, Asadollah

    2013-04-01

    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.

  8. Streptomycin-loaded PLGA-alginate nanoparticles: preparation, characterization, and assessment

    NASA Astrophysics Data System (ADS)

    Asadi, Asadollah

    2014-04-01

    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 t