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Sample records for ferrite nanoparticles prepared

  1. Preparation of cobalt-ferrite nanoparticles within a biopolymer template

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

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

  2. Magnetic hyperthermia heating of cobalt ferrite nanoparticles prepared by low temperature ferrous sulfate based method

    NASA Astrophysics Data System (ADS)

    Yadavalli, Tejabhiram; Jain, Hardik; Chandrasekharan, Gopalakrishnan; Chennakesavulu, Ramasamy

    2016-05-01

    A facile low temperature co-precipitation method for the synthesis of crystalline cobalt ferrite nanostructures using ferrous sulfate salt as the precursor has been discussed. The prepared samples were compared with nanoparticles prepared by conventional co-precipitation and hydrothermal methods using ferric nitrate as the precursor. X-ray diffraction studies confirmed the formation of cubic spinel cobalt ferrites when dried at 110 °C as opposed to conventional methods which required higher temperatures/pressure for the formation of the same. Field emission scanning electron microscope studies of these powders revealed the formation of nearly spherical nanostructures in the size range of 20-30 nm which were comparable to those prepared by conventional methods. Magnetic measurements confirmed the ferromagnetic nature of the cobalt ferrites with low magnetic remanance. Further magnetic hyperthermia studies of nanostructures prepared by low temperature method showed a rise in temperature to 50 °C in 600 s.

  3. The preparation of MnZn-ferrite nanoparticles in water CTAB hexanol microemulsions

    NASA Astrophysics Data System (ADS)

    Makovec, D.; Kosak, A.; Drofenik, M.

    2004-04-01

    Magnetic MnZn-ferrite nanoparticles with a narrow size distribution were prepared in water-CTAB-hexanol microemulsions. The region of microemulsion stability in the system was determined, using the titration method, as a function of the temperature and of the type and concentration of solutes in the aqueous phase. The nanoparticles were prepared in a two-step process: the precipitation of the corresponding hydroxides, followed by oxidation of the Fe2+. The particle size was controlled by the composition of the microemulsion and the concentration of the reactants (the corresponding sulfates and a precipitation agent, tetramethyl ammonium hydroxide) in the aqueous solution of the microemulsion. The specific magnetization of the nanoparticles (measured at 13 kOe) was found to depend mainly on particle size: ranging from 1.3 emu g-1 for particles of approximately 2 nm in size to 7.3 emu g-1 for particles of approximately 5 nm in size.

  4. 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.

  5. Magnetic Properties of Cobalt-Ferrite Nanoparticles Prepared by a Sol-Gel Synthesis Technique

    NASA Astrophysics Data System (ADS)

    Ekiert, Thomas; Unruh, Karl; Carpenter, E.; Pettigrew, K.; Long, J.; Rolison, D.

    2007-03-01

    Cobalt-ferrite nanoparticles have been prepared as highly porous aerogels using a sol-gel technique and characterized by XRD, TEM, and nitrogen-sorption porosimetry measurements. The XRD patterns for calcined Co-ferrite aerogels corresponded to a cubic structure with a lattice parameter near that of bulk Co-ferrite and a particle size of about 6 nm. TEM images indicated a similar particle size and a morphology similar to that of silica aerogels. The magnetic properties of these materials have been studied from 5 K to 340 K. Hysteresis loop measurements indicated that the coercivity and saturation magnetization of these materials evolves from nearly 19 kOe and 56 emu/g at 5 K to less than 10 Oe and 40 emu/g at 340 K. ZFC magnetization curves displayed a broad maximum that smoothly varied between about 300 K in an applied field of 100 Oe to about 180 K in a 10 kOe field. These measurements have been interpreted in terms of a distribution of effective particle sizes arising from a distribution in interparticle interactions.

  6. 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.

  7. 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

    2016-09-01

    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. PMID:27514793

  8. 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

    2016-09-01

    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.

  9. 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.

  10. The amazing effects and role of PVP on the crystallinity, phase composition and morphology of nickel ferrite nanoparticles prepared by thermal treatment method

    NASA Astrophysics Data System (ADS)

    Goodarz Naseri, Mahmoud; Saion, Elias; Khalil Zadeh, Nasrin

    2013-04-01

    Nickel ferrite nanocrystals were prepared from an aqueous solution containing metal nitrates and various concentrations of poly(vinylpyrrolidone) followed by calcination temperature. X-ray diffraction (XRD) analysis was performed to determine the degree of crystallinity of the ferrite nanoparticles. By transmission electron microscopy, the morphology and average particle size of the nickel ferrite nanoparticles were evaluated which had good agreement with the XRD results. Fourier transform infrared spectroscopy suggested the presence of metal oxide bands in all samples as well as the effective elimination of organic constituents after calcinations. Measurements of the extent of magnetization of the nickel ferrite nanoparticles synthesized in different concentrations were obtained at room temperature using a vibrating sample magnetometer.

  11. [Preparation and characterization of Mn-Zn ferrite oxygene nanoparticle for tumor thermotherapy].

    PubMed

    Jia, Xiupeng; Zhang, Dongsheng; Zheng, Jie; Gu, Ning; Zhu, Weichang; Fan, Xiangshan; Jin, Liqiang; Wan, Meiling; Li, Qunhui

    2006-12-01

    With the sulfate as the materials and NaOH as precipitator, Mn(0.4)Zn(0.6)Fe2O4 nanoparticles were produced, which are proved to be spinel Mn-Zn ferrite analyzed by X-ray diffraction(XRD). Their shapes are approximately global examined by transmission electron microscopy(TEM) and their average diameter is 50 nm measured with image analysis-system. The Curie temperature was measured and in vitro heating test in a alternating magnetic field was carried out. The results show that the Curie temperature is 105. 407 degrees C, While its magnetic fluid could rise to 43 degrees C - 47 degrees C due to different concentration in a alternating magnetic field. The result provide theoretical and practical evidence to select an appropriate material and concentration for tumor

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  14. 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.

  15. 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. PMID:25331121

  16. 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.

  17. 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. PMID:27398508

  18. 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.

  19. 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.

  20. Atomic engineering of mixed ferrite and core-shell nanoparticles.

    PubMed

    Morrison, Shannon A; Cahill, Christopher L; Carpenter, Everett E; Calvin, Scott; Harris, Vincent G

    2005-09-01

    Nanoparticulate ferrites such as manganese zinc ferrite and nickel zinc ferrite hold great promise for advanced applications in power electronics. The use of these materials in current applications requires fine control over the nanoparticle size as well as size distribution to maximize their packing density. While there are several techniques for the synthesis of ferrite nanoparticles, reverse micelle techniques provide the greatest flexibility and control over size, crystallinity, and magnetic properties. Recipes for the synthesis of manganese zinc ferrite, nickel zinc ferrite, and an enhanced ferrite are presented along with analysis of the crystalline and magnetic properties. Comparisons are made on the quality of nanoparticles produced using different surfactant systems. The importance of various reaction conditions is explored with a discussion on the corresponding effects on the magnetic properties, particle morphology, stoichiometry, crystallinity, and phase purity.

  1. 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.

  2. 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.

  3. A biosensor system using nickel ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Singh, Prachi; Rathore, Deepshikha

    2016-05-01

    NiFe2O4 ferrite nanoparticles were synthesized by chemical co-precipitation method and the structural characteristics were investigated using X-ray diffraction technique, where single cubic phase formation of nanoparticles was confirmed. The average particle size of NiFe2O4 was found to be 4.9 nm. Nanoscale magnetic materials are an important source of labels for biosensing due to their strong magnetic properties which are not found in biological systems. This property of the material was exploited and the fabrication of the NiFe2O4 nanoparticle based biosensor was done in the form of a capacitor system, with NiFe2O4 as the dielectric material. The biosensor system was tested towards different biological materials with the help of electrochemical workstation and the same was analysed through Cole-Cole plot of NiFe2O4. The performance of the sensor was determined based on its sensitivity, response time and recovery time.

  4. 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. PMID:26405858

  5. 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. PMID:26925725

  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. 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.

  8. 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.

  9. 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.

  10. 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.

  11. In situ synthesis of magnetic MnZn-ferrite nanoparticles using reverse microemulsions

    NASA Astrophysics Data System (ADS)

    Košak, A.; Makovec, D.; Drofenik, M.; Žnidaršič, A.

    2004-05-01

    Superparamagnetic MnZn-ferrite nanoparticles with a narrow size distribution were prepared at various pH values using precipitation in a reverse microemulsion consisting of hexanol, as an oil phase; surfactant CTAB; and an aqueous solution of metal sulfates. Tetramethyl ammonium hydroxide was used as the precipitating agent and hydrogen peroxide as the oxidizing reagent. The synthesized materials were characterized using X-ray diffractometry, transmission electron microscopy, BET surface analysis and magnetometry.

  12. Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Bakhshi, Hamed; Shokuhfar, Ali; Vahdati, Nima

    2016-09-01

    Cobalt ferrite nanoparticles (CFNPs) were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition (TCVD). In this process, acetylene gas (C2H2) was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750°C. The Ar/C2H2 ratio was 10:1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples' magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond- like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

  13. Oriented attachment explains cobalt ferrite nanoparticle growth in bioinspired syntheses.

    PubMed

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

    2014-01-01

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

  14. 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. PMID:23852534

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

    NASA Astrophysics Data System (ADS)

    Gabal, M. A.

    2009-10-01

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

  16. 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.

  17. 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.

  18. Chemisorption of cyanogen chloride by spinel ferrite magnetic nanoparticles.

    PubMed

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

    2013-05-01

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

  19. Cr(3+) substituted spinel ferrite nanoparticles with high coercivity.

    PubMed

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

    2016-06-17

    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 Cr(3+), 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. PMID:27159283

  20. 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.

  1. Cr(3+) substituted spinel ferrite nanoparticles with high coercivity.

    PubMed

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

    2016-06-17

    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 Cr(3+), 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.

  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 structural characterization of vulcanized natural rubber nanocomposites containing nickel-zinc ferrite nanopowders.

    PubMed

    Bellucci, F S; Salmazo, L O; Budemberg, E R; da Silva, M R; Rodríguez-Pérez, M A; Nobre, M A L; Job, A E

    2012-03-01

    Single-phase polycrystalline mixed nickel-zinc ferrites belonging to Ni0.5Zn0.5Fe2O4 were prepared on a nanometric scale (mean crystallite size equal to 14.7 nm) by chemical synthesis named the modified poliol method. Ferrite nanopowder was then incorporated into a natural rubber matrix producing nanocomposites. The samples were investigated by means of infrared spectroscopy, X-ray diffraction, scanning electron microscopy and magnetic measurements. The obtained results suggest that the base concentration of nickel-zinc ferrite nanoparticles inside the polymer matrix volume greatly influences the magnetic properties of nanocomposites. A small quantity of nanoparticles, less than 10 phr, in the nanocomposite is sufficient to produce a small alteration in the semi-crystallinity of nanocomposites observed by X-ray diffraction analysis and it produces a flexible magnetic composite material with a saturation magnetization, a coercivity field and an initial magnetic permeability equal to 3.08 emu/g, 99.22 Oe and 9.42 x 10(-5) respectively. PMID:22755110

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

    PubMed

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

    2014-06-01

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

  5. 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

  6. 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.

  7. Magnetic heating of silica-coated manganese ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    Manganese ferrite nanoparticles were synthesized using the reverse micelle method; these particles were then coated with silica. The silica-coated nanoparticles were spherical in shape, with an average diameter of 14 nm. The inverse spinel crystalline structure was observed through X-ray diffraction patterns. The coating status of silica on the surface of the nanoparticles was confirmed with a Fourier transform infrared spectrometer. The superparamagnetic properties were revealed by the zero coercive force in the hysteresis curve. Controllable heating at a fixed temperature of 42 °C was achieved by changing either the concentration of nanoparticles in the aqueous solution or the intensity of the alternating magnetic field. We found that at a fixed field strength of 5.5 kA/m, the 2.6 mg/ml sample showed a saturation temperature of 42 °C for magnetic hyperthermia. On the other hand, at a fixed concentration of 3.6 mg/ml, a field intensity of 4.57 kA/m satisfied the required temperature of 42 °C.

  8. 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

  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. Polyethylene glycol coated CoFe2O4 nanoparticles: A potential spinel ferrite for biomedical applications

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    The structural and magnetic properties of the polyethylene glycol (PEG) coated cobalt spinel ferrite (CoFe2O4) nanoparticles have been reported in the present study. CoFe2O4 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 CoFe2O4 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 CoFe2O4 nanoparticles were calculated by using XRD data. The presence of PEG on CoFe2O4 nanoparticles and reduced agglomeration in the CoFe2O4 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.

  11. Role of surface charge in cytotoxicity of charged manganese ferrite nanoparticles towards macrophages

    NASA Astrophysics Data System (ADS)

    Yang, Seung-Hyun; Heo, Dan; Park, Jinsung; Na, Sungsoo; Suh, Jin-Suck; Haam, Seungjoo; Park, Sahng Wook; Huh, Yong-Min; Yang, Jaemoon

    2012-12-01

    Amphiphilic surfactants have been used to disperse magnetic nanoparticles in biological media, because they exhibit a dual hydrophobic/hydrophilic affinity that facilitates the formation of a nanoemulsion, within which nanoparticle surfaces can be modified to achieve different physicochemical properties. For the investigation of the interactions of cells with charged magnetic nanoparticles in a biological medium, we selected the nanoemulsion method to prepare water-soluble magnetic nanoparticles using amphiphilic surfactant (polysorbate 80). The hydroxyl groups of polysorbate 80 were modified to carboxyl or amine groups. The chemical structures of carboxylated and aminated polysorbate 80 were confirmed, and water-soluble manganese ferrite nanoparticles (MFNPs) were synthesized with three types of polysorbate 80. Colloidal size, morphology, monodispersity, solubility and T2 relaxivity were found to be similar between the three types of MFNP. However, cationic MFNPs exhibited greater cytotoxicity in macrophages (RAW264.7 cells) and lower cellular membrane effective stiffness than anionic and non-ionic MFNPs. Moreover, cationic MFNPs exhibited large uptake efficiency for RAW264.7 cells compared with anionic or non-ionic MFNPs under the same conditions. Therefore, we propose that surface charge should be a key consideration factor in the design of magnetic nanoparticles for theragnostic applications.

  12. Room temperature optical and dielectric properties of Sr and Ni doped lanthanum ferrite nanoparticles

    SciTech Connect

    Naseem, Swaleha; Khan, Wasi Singh, B. R.; Naqvi, A. H.

    2015-06-24

    Strontium and nickel doped lanthanum ferrite (LaFeO{sub 3}) nanoparticles (NPs) were prepared reverse micelle (RM) and calcinated at 700°C. Microstructural studies were carried by XRD and SEM/EDS techniques. The results of structural characterization show the formation of all samples in single phase without any impurity. Optical properties were studied by UV- visible spectroscopy and band gap energy was estimated 3.89 eV. Room temperature dielectric constant (ε’) decreases abruptly at lower frequencies owing to the charge transport relaxation time. The observed behavior of the dielectric properties can be attributed on the basis of Koop’s theory based on Maxwell-Wagner’s two layer model in studied nanoparticles.

  13. Mössbauer studies of nanosized ferrites prepared by the combustion of metal nitrates oxalyl dihydrazide solutions

    NASA Astrophysics Data System (ADS)

    Gandotra, Karun; Randhawa, B. S.

    2008-07-01

    Alkaline earth metal ferrites have been prepared by combustion of redox mixtures containing metal nitrates and oxalyl dihydrazide (ODH) at 673 K. On rapid heating, ODH metal nitrate mixture undergoes an abrupt exothermic redox chemical reaction that facilitates atomic scale mixing of cations. This leads to the formation of stoichiometrically pure and single-phase nanoparticle ferrites at comparatively reduced temperature (400°C) and in less time than possible by the conventional ceramic method. Because of their different cationic size, polarizability etc., alkaline earth metal cations yield different type of ferrites i.e. MFe2O4 (M = Mg, Ba), Ca2Fe2O5 and SrFe12O19.

  14. 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

  15. 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.

  16. Electrophoretic deposition of nickel zinc ferrite nanoparticles into microstructured patterns

    NASA Astrophysics Data System (ADS)

    Kelly, Stefan J.; Wen, Xiao; Arnold, David P.; Andrew, Jennifer S.

    2016-05-01

    Using DC electric fields, nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4) nanoparticles (Dh =16.6 ± 3.6 nm) are electrophoretically deposited onto silicon substrates to form dense structures defined by photoresist molds. Parameters such as electric field, bath composition, and deposition time are tuned to produce films ranging in thickness from 177 to 805 nm. The deposited films exhibit soft magnetic properties with a saturation magnetization of 60 emu/g and a coercivity of 2.6 kA/m (33 Oe). Additionally, the influence of the photoresist mold on the deposit profile is studied, and patterned films with different shapes (lines, squares, circles, etc.) are demonstrated with feature sizes down to 5 μm.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Chitosan-coated nickel-ferrite nanoparticles as contrast agents in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ahmad, Tanveer; Bae, Hongsub; Iqbal, Yousaf; Rhee, Ilsu; Hong, Sungwook; Chang, Yongmin; Lee, Jaejun; Sohn, Derac

    2015-05-01

    We report evidence for the possible application of chitosan-coated nickel-ferrite (NiFe2O4) nanoparticles as both T1 and T2 contrast agents in magnetic resonance imaging (MRI). The coating of nickel-ferrite nanoparticles with chitosan was performed simultaneously with the synthesis of the nickel-ferrite nanoparticles by a chemical co-precipitation method. The coated nanoparticles were cylindrical in shape with an average length of 17 nm and an average width of 4.4 nm. The bonding of chitosan onto the ferrite nanoparticles was confirmed by Fourier transform infrared spectroscopy. The T1 and T2 relaxivities were 0.858±0.04 and 1.71±0.03 mM-1 s-1, respectively. In animal experimentation, both a 25% signal enhancement in the T1-weighted mage and a 71% signal loss in the T2-weighted image were observed. This demonstrated that chitosan-coated nickel-ferrite nanoparticles are suitable as both T1 and T2 contrast agents in MRI. We note that the applicability of our nanoparticles as both T1 and T2 contrast agents is due to their cylindrical shape, which gives rise to both inner and outer sphere processes of nanoparticles.

  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. 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.

  5. 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.

  6. 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.

  7. Magnetic properties of cobalt-ferrite nanoparticles embedded in polystyrene resin

    SciTech Connect

    Vaishnava, P. P.; Senaratne, U.; Buc, E.; Naik, R.; Naik, V. M.; Tsoi, G.; Wenger, L. E.; Boolchand, P.

    2006-04-15

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

  8. 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

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    Ferrite nanoparticles of basic composition Ni0.7Mg0.3Fe2-xAlxO4 (0.0≤x≤0.5) were prepared through citrate gel method and characterized using XRD, TEM and dielectric spectroscopy techniques. The dielectric properties were studied as a function of frequency (42 Hz-5 MHz) at room temperature. The average particle size has been found between 8-17 nm. The dispersion in dielectric properties and ac conductivity (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 Ni2+ and Ni3+ ions at B-sites. The dielectric loss tangent (tan δ) shows abnormal behavior for the compositions 0.3, 0.4 and 0.5 which has been explained in the light of Rezlescue model.

  12. Ferrite with extraordinary electric and dielectric properties prepared from self-combustion technique

    SciTech Connect

    Chen Qian; Du Piyi; Huang Wenyan; Jin Lu; Weng Wenjian; Han Gaorong

    2007-03-26

    Nickel-zinc ferrites (Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}) with extraordinary electric and dielectric properties were prepared by self-combustion technique. The resistivity of ferrite in the ferric citrate system is on the order of 10{sup 10} {omega} cm, which is about four orders higher than that of ferrite in the ferric nitrate system as well as that of ferrite prepared by the conventional method. The dielectric loss of sample in the ferric citrate system is only 0.008. The amorphous phase and its encapsulation well around the grains have played most important roles in both high resistivity and low dielectric loss of ferrite in the ferric citrate system.

  13. 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.

  14. Low-temperature synthesis and thermal study of manganese-zinc ferrite nanoparticles by a ferrioelate precursor method

    NASA Astrophysics Data System (ADS)

    Lal, Madan; Singh, M.

    2006-12-01

    The procedure adopted for preparing the ferrite formation was found to be quite sensitive. The chlorine ion concentration and the pH in the solution has played a crucial role in retaining the initial stoichiometry of the solution in the nanoparticles. This work had the objective of studying the nanoparticle Mn-Zn ferrite obtained by the ferrioelate precursor method. In this process, Mn-Zn ferrite, synthesized through solutions of some specific salts led to the formation of crystalline power (10-30nm as evident from X-ray diffraction analysis) at a temperature of 2000C. The synthesis powders were characterized by X-ray diffractometer for identification of the crystalline phases present, by scanning electron microscopy for identification for their morphological structure and properties, thermogarvimetry and differential thermal analysis for identification of the oxidation/ reduction behaviour upon firing. The fourier transformation infrared spectroscopy (FT-IR) shows two main absorption bands v1 and v2 in the range of 4000-500cm-1and Differential Scanning Calorimetry (DSC) of the Mn0.4Zn0.6Fe2O4 powder at 5000C predicts the exothermic and endothermic reaction with the change in temperature with respect to heat flow. The synthesis route is simple, energy saving and cost effective. Details of the synthesis and characterizations of the resultant products were given.

  15. Control of the saturation temperature in magnetic heating by using polyethylene-glycol-coated rod-shaped nickel-ferrite (NiFe2O4) nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    Polyethylene-glycol (PEG)-coated nickel-ferrite nanoparticles were prepared for magnetic hyperthermia applications by using the co-precipitation method. The PEG coating occurred during the synthesis of the nanoparticles. The coated nanoparticles were rod-shaped with an average length of 16 nm and an average diameter of 4.5 nm, as observed using transmission electron microscopy. The PEG coating on the surfaces of the nanoparticles was confirmed from the Fourier-transform infrared spectra. The nanoparticles exhibited superparamagnetic characteristics with negligible coercive force. Further, magnetic heating effects were observed in aqueous solutions of the coated nanoparticles. The saturation temperature could be controlled at 42 ℃ by changing the concentration of the nanoparticles in the aqueous solution. Alternately, the saturation temperature could be controlled for a given concentration of nanoparticles by changing the intensity of the magnetic field. The Curie temperature of the nanoparticles was estimated to be 495 ℃. These results for the PEG-coated nickel-ferrite nanoparticles showed the possibility of utilizing them for controlled magnetic hyperthermia at 42 ℃.

  16. 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.

  17. 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.

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  20. Magnetic properties of conducting polymer doped with manganese zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

    The magnetic properties of superparamagnetic particles are influenced by the supporting matrix. We have systematically studied the DC magnetic properties of loosely packed manganese-zinc ferrite (Mn0.68Zn0.25Fe2.07O3) nanoparticles synthesized using a reverse micelle technique. The results have been compared with those for particles suspended in paraffin wax and embedded in a polypyrrole matrix. The polypyrrole-doped particles were prepared using an in situ ultraviolet irradiation method and spin-coated into thin films. The loosely packed particles showed no resolvable coercivity even well below the blocking temperature. On the other hand, the same particles in wax showed the opening up of a large coercivity below the blocking temperature. However, both the samples showed characteristic superparamagnetic transition peaks in the temperature-dependent susceptibility nearly at the same temperature. The particles in the polypyrrole matrix showed a remarkable increase in the blocking temperature and large hysteresis at 300 K. The structural characterization of the polymer-doped sample showed clustering of the nanoparticles.

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

    PubMed Central

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

    2013-01-01

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

  2. 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.

  3. 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.

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

    PubMed

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

    2012-03-30

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

  5. 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.

  6. Magnetic properties of bio-synthesized zinc ferrite nanoparticles

    SciTech Connect

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

    2011-01-01

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

  7. Frequency-dependent magnetic susceptibility of magnetite and cobalt ferrite nanoparticles embedded in PAA hydrogel.

    PubMed

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

    2013-05-14

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

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

    PubMed Central

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

    2013-01-01

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

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  11. 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

  12. 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.

  13. 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. PMID:27563243

  14. Spherical barium ferrite nanoparticles and hexaferrite single crystals for information data storage and RF devices

    NASA Astrophysics Data System (ADS)

    Jalli, Jeevan Prasad

    Since their discovery in the early 1950's hexagonal ferrites or hexaferrites have been studied for a long time because of their technological applications, such as microwave devices and high density magnetic recording media. In this dissertation efforts have been made to address these two applications by developing nanosized spherical barium ferrite particles for advanced magnetic recording media, and hexaferrite single crystals for low loss RF devices. Accordingly, this dissertation consists of two parts; part one spherical barium ferrite nanoparticles for information data storage media, and part two hexaferrite single crystals for RF devices. Part I. Spherical Barium Ferrite Nanoparticles Hexagonal barium ferrite (H-BaFe) nanoparticles are good candidates for particulate recording media due to their high uniaxial magnetocrystalline anisotropy, excellent chemical stability, and narrow switching field distribution. One major disadvantage of using H-BaFe particles for particulate recording media is their poor dispersion and a high degree of stacking that deteriorate the recording capability by creating large media noise and surface roughness. One way to solve and improve the recording performance of H-BaFe media is employing substantially nanosized spherical barium ferrite (S­BaFe) particles. Spherical shaped particles have low aspect ratio and only form a point-to-point contact, unlike the H-BaFe particles. Therefore, using S-BaFe particles not only decrease the degree of magnetic interaction between the particles but also can substantially increases the recording performance by improving the dispersion and SNR of the particles in the magnetic media. In this dissertation, two different approaches were employed successfully to synthesize S-BaFe nanoparticles in the range of 20-45 nm. Part II. Hexaferrite Single Crystals As wireless communication systems are flourishing, and the operating frequencies are increasing, there is a great demand for RF devices such as

  15. Galactosylated manganese ferrite nanoparticles for targeted MR imaging of asialoglycoprotein receptor.

    PubMed

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

    2013-11-29

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  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

    2014-11-01

    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. PMID:25232657

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Ni-Cu-Zn Ferrite Powder Prepared from Steel Pickled Liquor and Electroplating Waste Solutions

    NASA Astrophysics Data System (ADS)

    Liu, Chung-Wen; Fu, Yen-Pei; Lin, Cheng-Hsiung

    2007-03-01

    In this study, we propose a new method of synthesizing Ni-Cu-Zn ferrite powder using steel pickled liquor and electroplating waste solutions as starting materials. It was found that the Ni-Cu-Zn ferrite powder prepared by a hydrothermal process from the waste solutions shows the formation of cubic ferrite with a saturation magnetization (Ms) of 31.5 emu/g and an intrinsic coercive force (Hci) of 19.3 Oe. Upon annealing at 750 °C for 2 h, the saturation magnetization increases to 52.6 emu/g and the intrinsic coercive force reaches 42.8 Oe. This useful method can promote the recycling of industrial waste solution and contribute to the preservation of the earth. Moreover, this method decreases the manufacturing cost in the treatment of the industrial waste solution for electroplating and steel industries.

  10. 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. PMID:26942534

  11. 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.

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

    PubMed

    Lisjak, Darja; Jenuš, Petra; Mertelj, Alenka

    2014-06-10

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

  13. 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.

  14. 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

  15. 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

  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.; Han, Jinkyu; Zhang, Cheng; Li, Qiang; Shi, Chenyang; Abeykoon, A. M.Milinda; Billinge, Simon J.L.; Stach, Eric; et al

    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. Method for preparing spherical ferrite beads and use thereof

    DOEpatents

    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.

  19. Citric Acid Fuctionalized Magnetic Ferrite Nanoparticles for Photocatalytic Degradation of Azo Dye.

    PubMed

    Mahto, Triveni Kumar; Roy, Anurag; Sahoo, Banalata; Sahu, Sumanta Kumar

    2015-01-01

    In this study different magnetic ferrite nanoparticles (MFe2O4, where M = Fe, Mn, Zn) were synthesized through an aqueous coprecipitation method and then functionalized with citric acid for the degradation of azo dye present in industrial waste water. Here we evaluated the role of citric acid for photocatalytic application. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and the catalytic activity in degradation of methyl orange (MO) was evaluated. The rate of MO degradation in different magnetic systems was determined by UV-Vis spectroscopy. The effect of active parameters (pH, initial MO concentration and effect of sunlight) on degradation performance was investigated. For the first time, citric acid chemistry is successfully exploited to develop a photocatalyst that can successfully degrade the dyes. This citric acid functionalized magnetic ferrite nanoparticles are very much effective for photocalytic degradation of dye and also these can be recollected with the help of permanent magnet for successive uses.

  20. Correlation of spin and structure in doped bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Lin, J. W.; Tite, Teddy; Tang, Y. H.; Lue, C. S.; Chang, Y. M.; Lin, J. G.

    2012-04-01

    The mutiferroic Bi1-xEuxFeO3 nanoparticles with x = 0 to 0.4 are studied by x-ray diffraction (XRD), Raman spectra and electron spin resonance (ESR) with X-band (9.53 GHz), in order to investigate the doping effect on crystalline and spin structures. Both XRD and Raman spectrum reveal a structural transformation at x = 0.15, which is associated with the shortening of Bi—O bond length. These structural data are further related to the variation of ESR peak position and peak area, providing evidence for the enhancement of ferromagnetic coupling as x < 0.3.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  4. Study of the preparation of NI-Mn-Zn ferrite using spent NI-MH and alkaline Zn-Mn batteries

    NASA Astrophysics Data System (ADS)

    Xi, Guoxi; Xi, Yuebin; Xu, Huidao; Wang, Lu

    2016-01-01

    Magnetic nanoparticles of Ni-Mn-Zn ferrite have been prepared by a sol-gel method making use of spent Ni-MH and Zn-Mn batteries as source materials. Characterization by X-ray diffraction was carried out to study the particle size. The presence of functional groups was identified by Fourier transform infrared spectroscopy. From studies by thermogravimetry and differential scanning calorimetry, crystallization occurred at temperatures above 560 °C. The magnetic properties of the final products were found to be directly influenced by the average particle size of the product. The Ms values increase and the Hc values decrease as the size of the Ni-Mn-Zn ferrite particles increases.

  5. Structural and Mossbauer spectroscopic studies of heat-treated NixZn1-xFe2O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Meena, S. S.; Tirupanyam, B. V.; Sastry, D. L.; Yusuf, S. M.

    2013-02-01

    NixZn1-xFe2O4(x = 0.5,0.6,0.7) nanoparticles were prepared using coprecipitation method and were heat treated at 200, 500 and 800 °C. Structure and hyperfine interactions were studied by X-ray diffraction and Mössbauer spectroscopic techniques, respectively. The particle size increases with increasing the heat treatment (HT) temperature and Ni ion concentration. Only a quadrupole doublet was observed for Ni0.5Zn0.5Fe2O4 ferrite, heat treated at 200 °C. For higher heat treatment temperatures, hyperfine sextets appear and become predominant in nanoparticles with 800 °C HT. However, the quadrupole doublet remains with reduced intensity. The results interpreted in terms of an existence of size distribution of nanoparticles.

  6. 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.

  7. Screen-printing of ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides

    NASA Astrophysics Data System (ADS)

    Martirosyan, Karen S.; Dannangoda, Chamath; Galstyan, Eduard; Litvinov, Dmitri

    2012-05-01

    The feasibility of screen-printing process of hard ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides (CCSO) is investigated. In CCSO, the exothermic oxidation of carbon generates a smolder thermal reaction wave that propagates through the solid reactant mixture converting it to the desired oxides. The complete conversion of hexaferrites occurs using reactant mixtures containing 11 wt. % of carbon. The BaFe12O19 and SrFe12O19 hexaferrites had hard magnetic properties with coercivity of 3 and 4.5 kOe, respectively. It was shown that the synthesized nanoparticles could be used to fabricate permanent magnet structures by consolidating them using screen-printing techniques.

  8. Dielectric properties of polymer composites with the addition of ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kisiel, A.; Konieczny, M.; Zabska, M.

    2016-02-01

    The aim of the work was examination of the dielectric properties of a new type of polymer nanocomposites based on PVDF (polyvinylidene fluoride), or a copolymer P(VDF-HFP) with addition of ferrite nanoparticles. The addition of nanofillers leads not only to the formation of polar ß-phase of PVDF, which shows unique piro-, piezo- and ferroelectric properties used in many applications, but also affects the dielectric and magnetoelectric properties of these nanocomposites. In the work the dielectric properties of polymer composites, such as volume resistivity, permittivity and dielectric loss were investigated Measurements of dielectric parameters were performed in a climate chamber at temperature range of 25-100°C, at selected frequencies in the range 20-200 kHz. The results obtained are valuable not only for an application of this type of nanocomposites in various types of transducers, but also for analysis of the physical phenomena occurring in the polymer composites doped with nanoparticles.

  9. 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.

  10. 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

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

    PubMed

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

    2013-03-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

    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 (MnFe2O4, Fe3O4) 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 (pc = 6.39 MPa and Tc = 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.

  13. 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.

  14. 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 .

  15. 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.

  16. 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…

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

    NASA Astrophysics Data System (ADS)

    Jović, N.; Prekajski, M.; Kremenović, A.; Jančar, B.; Kahlenberg, V.; Antić, B.

    2012-02-01

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

  18. Preparation and characterization of Ni-Zn ferrite + polymer nanocomposites using mechanical milling method

    NASA Astrophysics Data System (ADS)

    Raju, P.; Murthy, S. R.

    2013-12-01

    The insulating properties of Ni-Zn ferrites can be improved by the addition of various types of insulating materials such as polymers, ceramics, etc. In this connection, ferrite-polymer composites have been subjected to extensive research, because they have many applications: electromagnetic interference shielding, rechargeable battery, electrodes and sensors, and microwave absorption. Electrical and magnetic properties of such composites will depend on the size, shape and amount of filler addition. In this paper, we report the preparation and characterization of nanocomposites of Ni-Zn ferrite + paraformaldehyde. These nanocomposites were prepared by using mechanical milling method and characterized by X-ray powder diffraction, scanning electron microscopy (SEM) and Fourier transform infrared spectrometer. The particle size estimated from SEM pictures for composites varies from 36 to 60 nm. Magnetic properties were measured on nanocomposites at room temperature. The complex permittivity and permeability were measured over a wide frequency range from 1 MHz to 1.8 GHz at room temperature. From our studies, it is observed that both the values of permittivity and permeability decrease with an increase in polymer content.

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

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

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

  20. New methods for lipid nanoparticles preparation.

    PubMed

    Corrias, Francesco; Lai, Francesco

    2011-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

    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. This indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.

  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. 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.

  5. 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.

  6. 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. PMID:27375215

  7. Effect of Ni2+ substitution on structural and magnetic properties of Ni-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Tirupanyam, B. V.; Satish, A.; Seshubai, V.; Sastry, D. L.; Caltun, O. F.

    2015-05-01

    A series of co-precipitated NixZn1-xFe2O4 (x=0.5, 0.6, 0.7) ferrite nanoparticles heat treated at 200 °C were produced in order to understand the influence of substitution level on structural and magnetic properties including magnetocrystalline anisotropy. The XRD, FE-SEM, VSM and FC-ZFC techniques were used to characterize the samples. It is observed that as Ni2+ concentration increases crystallite size (D), saturation magnetization (Ms) and blocking temperature (TB) and decreases coercive field (Hc). All particles exhibit superparamagnetism at room temperature and hence lie in the single domain range. The magnetic anisotropy constant (K) is estimated to be maximum for Ni0.5Zn0.5Fe2O4 sample, whose particle size is the smallest. The results are interpreted presuming the presence of core shell interactions and/or cation redistribution that influence the magnetic properties of these ferrite nano particles.

  8. 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. PMID:23466007

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

    PubMed

    N, Venkatesha; Srivastava, Chandan; Hegde, Veena

    2014-12-01

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

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

    PubMed

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

    2012-08-01

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

  11. 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.

  12. The synthesis of spinel ferrite nanoparticles using precipitation in microemulsions for ferrofluid applications

    NASA Astrophysics Data System (ADS)

    Makovec, Darko; Košak, Aljoša; Žnidaršič, Andrej; Drofenik, Miha

    2005-03-01

    Magnetic maghemite nanoparticles with a narrow size distribution were prepared in water-CTAB-hexanol-butanol microemulsions. The particle size was controlled with the composition of the microemulsion (water-to-CTAB ratio) and the temperature during synthesis. The saturation magnetization of the nanoparticles depended mainly on their size, ranging from 22 emu/g for a particle size of 3.4 nm to 64 emu/g for a size of 15.3 nm.

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

    PubMed

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

    2011-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  16. Development of phosphonate modified Fe 1-x MnxFe2O4 mixed ferrite nanoparticles: novel peroxidase mimetics in enzyme linked immunosorbent assay.

    PubMed

    Bhattacharya, Dipsikha; Baksi, Ananya; Banerjee, Indranil; Ananthakrishnan, Rajakumar; Maiti, Tapas K; Pramanik, Panchanan

    2011-10-30

    A highly facile and feasible strategy on the fabrication of advanced intrinsic peroxidase mimetics based on Mn(2+) doped mixed ferrite (Mn(II)(x)Fe(II)(1-x)Fe(III)(2)O(4)) nanoparticles was demonstrated for the quantitative and sensitive detection of mouse IgG (as a model analyte). Mn(2+) doped Fe(1-x)Mn(x)Fe(2)O(4) nanoparticles were synthesized using varying ratios of Mn(2+):Fe(2+) ions and characterized by the well known complementary techniques. The increase of Mn(2+) proportion had remarkably enhanced the peroxidase activity and magnetism. The catalytic activity of mixed ferrites was found to follow Michaelis-Menten kinetics and was noticeably higher than native Fe(3)O(4). The calculated K(m) and K(cat) exhibited strong affinity with substrates which were remarkably higher than similar sized native magnetite nanoparticles and horseradish peroxidase (HRP). These findings stimulated us to develop carboxyl modified Fe(1-x)Mn(x)Fe(2)O(4) nanoparticles using phosphonomethyl immunodiacetic acid (PMIDA) to engineer PMIDA-Fe(1-x)Mn(x)Fe(2)O(4) fabricated enzyme linked immunosorbent assay (ELISA). Results of both PMIDA-Fe(1-x)Mn(x)Fe(2)O(4) linked ELISA revealed that the enhancements in absorbance during the catalysis of enzyme substrate were linearly proportional to the concentration of mouse IgG within the range between 0.1 μg/ml and 2.5 μg/ml. Further, this detection was ten times lower than previous reports and the detection limit of mouse IgG was 0.1 μg/ml. The advantages of our fabricated artificial peroxidase mimetics are combined of low cost, easy to prepare, better stability and tunable catalytic activity. Moreover, this method provides a new horizon for the development of promising analytical tools in the application of biocatalysis, bioassays, and bioseparation.

  17. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  20. 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.

  1. Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

    PubMed

    Vaculikova, Eliska; Cernikova, Aneta; Placha, Daniela; Pisarcik, Martin; Peikertova, Pavlina; Dedkova, Katerina; Devinsky, Ferdinand; Jampilek, Josef

    2016-01-01

    Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide. PMID:27490530

  2. Preparation and characterization of Mg nanoparticles

    SciTech Connect

    Song Meirong; Chen Miao Zhang Zhijun

    2008-05-15

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

  3. Preparation, characterization and utilization of starch nanoparticles.

    PubMed

    Kim, Hee-Young; Park, Sung Soo; Lim, Seung-Taik

    2015-02-01

    Starch is one of the most abundant biopolymers in nature and is typically isolated from plants in the form of micro-scale granules. Recent studies reported that nano-scale starch particles could be readily prepared from starch granules, which have unique physical properties. Because starch is environmentally friendly, starch nanoparticles are suggested as one of the promising biomaterials for novel utilization in foods, cosmetics, medicines as well as various composites. An overview of the most up-to-date information regarding the starch nanoparticles including the preparation processes and physicochemical characterization will be presented in this review. Additionally, the prospects and outlooks for the industrial utilization of starch nanoparticles will be discussed.

  4. 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.

  5. 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. PMID:27483815

  6. 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.

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

    SciTech Connect

    Lazarević, Z.Ž.; Jovalekić, Č.; Rečnik, A.; Ivanovski, V.N.; Milutinović, A.; Romčević, M.; Pavlović, M.B.; Cekić, B.; Romčević, N.Ž.

    2013-02-15

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

  8. Improved electrical properties of cadmium substituted cobalt ferrites nano-particles for microwave application

    NASA Astrophysics Data System (ADS)

    Ahmad, Rabia; Hussain Gul, Iftikhar; Zarrar, Muhammad; Anwar, Humaira; khan Niazi, Muhammad Bilal; Khan, Azim

    2016-05-01

    Cadmium substituted cobalt ferrites with formula CdxCo1-xFe2O4 (x=0.0, 0.2, 0.35, 0.5), have been synthesized by wet chemical co-precipitation technique. Electrical, morphological and Structural properties of the samples have been studied using DC electrical resistivity and Impedance analyzer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively. XRD, SEM and AFM have been used to study the structural parameters such as measured density, lattice constant, X-ray density, crystallite size and morphology of the synthesized nano-particles. Debye-Scherrer formula has been used for the estimation of crystallite sizes. The estimated crystallite sizes were to be 15-19±2 nm. Hopping length of octahedral and tetrahedral sites have been calculated using indexed XRD data. The porosity and lattice constant increased as Cd2+concentration increases. DC electrical resistivity was performed using two probe technique. The decrease of resistivity with temperature confirms the semiconducting nature of the samples. The dielectric properties variation has been studied at room temperature as a function of frequency. Variation of dielectric properties from 100 Hz to 5 MHz has been explained on the basis of Maxwell and Wagner's model and hoping of electrons on octahedral sites. To separates the grains boundary and grains of the system CdxCo1-xFe2O4 the impedance analysis were performed.

  9. Observation of magnetic anomalies in one-step solvothermally synthesized nickel-cobalt ferrite nanoparticles.

    PubMed

    Datt, Gopal; Sen Bishwas, Mousumi; Manivel Raja, M; Abhyankar, A C

    2016-03-01

    Magnetic anomalies corresponding to the Verwey transition and reorientation of anisotropic vacancies are observed at 151 K and 306 K, respectively, in NiCoFe2O4 nanoparticles (NPs) synthesized by a modified-solvothermal method followed by annealing. Cationic disorder and spherical shape induced non-stoichiometry suppress the Verwey transition in the as-synthesized NPs. On the other hand, reorientation of anisotropic vacancies is quite robust. XRD and electron microscopy investigations confirm a single phase spinel structure and the surface morphology of the as-synthesized NPs changes from spherical to octahedral upon annealing. Rietveld analysis reveals that the Ni(2+) ions migrate from tetrahedral (A) to octahedral (B) sites upon annealing. The Mössbauer results show canted spins in both the NPs and the strength of superexchange is stronger in Co-O-Fe than Ni-O-Fe. Magnetic force images show that the as-synthesised NPs are single-domain whereas the annealed NPs are multi-domain octahedral particles. The FMR study reveals that both the NPs have a broad FMR line-width; and resonance properties are consistent with the random anisotropy model. The broad inhomogeneous FMR line-width, observation of the Verwey transition, tuning of the magnetic domain structure as well as the magnetic properties suggest that the NiCoFe2O4 ferrite NPs may be promising for future generation spintronics, magneto-electronics, and ultra-high-density recording media as well as for radar absorbing applications.

  10. 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

  11. Dielectric study of Al3+ substituted Fe3O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  12. 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.

  13. Janus nanoparticles: preparation, characterization, and applications.

    PubMed

    Song, Yang; Chen, Shaowei

    2014-02-01

    In chemical functionalization of colloidal particles, the functional moieties are generally distributed rather homogeneously on the particle surface. Recently, a variety of synthetic protocols have been developed in which particle functionalization may be carried out in a spatially controlled fashion, leading to the production of structurally asymmetrical particles. Janus particles represent the first example in which the two hemispheres exhibit distinctly different chemical and physical properties, which is analogous to the dual-faced Roman god, Janus. Whereas a variety of methods have been reported for the preparation of (sub)micron-sized polymeric Janus particles, it has remained challenging for the synthesis and (unambiguous) structural characterization of much smaller nanometer-sized Janus particles. Herein, several leading methods for the preparation of nanometer-sized Janus particles are discussed and the important properties and applications of these Janus nanoparticles in electrochemistry, sensing, and catalysis are highlighted. Some perspectives on research into functional patchy nanoparticles are also given. PMID:24376180

  14. 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.

  15. Impact of Nd3+ in CoFe2O4 spinel ferrite nanoparticles on cation distribution, structural and magnetic properties

    NASA Astrophysics Data System (ADS)

    Yadav, Raghvendra Singh; Havlica, Jaromir; Masilko, Jiri; Kalina, Lukas; Wasserbauer, Jaromir; Hajdúchová, Miroslava; Enev, Vojtěch; Kuřitka, Ivo; Kožáková, Zuzana

    2016-02-01

    Nd3+ doped cobalt ferrite nanoparticles have been synthesized by starch-assisted sol-gel auto-combustion method. The significant role played by Nd3+ added to cobalt ferrite in changing cation distribution and further in influencing structural and magnetic properties, was explored and reported. The crystal structure formation and crystallite size were studied from X-ray diffraction studies. The microstructural features were investigated by field emission scanning electron microscopy and transmission electron microscopy that demonstrates the nanocrystalline grain formation with spherical morphology. An infrared spectroscopy study shows the presence of two absorption bands related to tetrahedral and octahedral group complexes within the spinel ferrite lattice system. The change in Raman modes in synthesized ferrite system were observed with Nd3+ substitution, particle size and cation redistribution. The impact of Nd3+ on cation distribution of Co2+ and Fe3+ at octahedral and tetrahedral sites in spinel ferrite cobalt ferrite nanoparticles was investigated by X-ray photoelectron spectroscopy. Room temperature magnetization measurements showed that the saturation magnetization and coercivity increase with addition of Nd3+ substitution in cobalt ferrite.

  16. Magnetic and Mössbauer spectroscopic studies of NiZn ferrite nanoparticles synthesized by a combustion method

    NASA Astrophysics Data System (ADS)

    Sreeja, V.; Vijayanand, S.; Deka, S.; Joy, P. A.

    2008-04-01

    The properties of nanocrystalline Ni0.5Zn0.5Fe2O4 synthesized by an auto-combustion method have been investigated by magnetic measurements and Mössbauer spectroscopy. The as-synthesized single phase nanosized ferrite powder is annealed at different temperatures in the range 673 1,273 K to obtain nanoparticles of different sizes. The powders are characterized by powder X-ray diffraction, vibrating sample magnetometer, transmission electron microscopy and Mössbauer spectroscopy. The as-synthesized powder with average particle size of ~9 nm is superparamagnetic. Magnetic transition temperature increases up to 665 K for the nanosized powder as compared to the transition temperature of 548 K for the bulk ferrite. This has been confirmed as due to the abnormal cation distribution, as evidenced from room temperature Mössbauer spectroscopic studies.

  17. 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

  18. Recovery of copper as zero-valent phase and/or copper oxide nanoparticles from wastewater by ferritization.

    PubMed

    Heuss-Aßbichler, Soraya; John, Melanie; Klapper, Daniel; Bläß, Ulrich W; Kochetov, Gennadii

    2016-10-01

    Recently the focus of interest changed from merely purification of the waste water to recover heavy metals. With the slightly modified ferritization process presented here it is possible to decrease initial Cu(2+) concentrations up to 10 g/l to values <0.3 mg/l. The recovery rates of copper of all experiments are in the rage of 99.98 to almost 100%. Copper can be precipitated as oxide or zero valent metal (almost) free of hydroxide. All precipitates are exclusively of nanoparticle size. The phase assemblage depends strongly on experimental conditions as e.g. reaction temperature, pH-value, initial concentration and ageing time and condition. Three different options were developed depending on the reaction conditions. Option 1.) copper incorporation into the ferrite structure ((Cu,Fe)Fe2O4) and/or precipitation as cuprite (Cu2O) and zero-valent copper, option 2.) copper incorporation into the ferrite structure and/or precipitation as cuprite and/or tenorite (CuO) and option 3.) copper precipitation as tenorite. Ferrite is formed by the oxidation of GR in alkaline solution without additional oxygen supply. The chemistry reaches from pure magnetite up to 45% copper ferrite component. First experiments with wastewater from electroplating industry confirm the results obtained from synthetic solutions. In all cases the volume of the precipitates is extremely low compared to typical wastewater treatment by hydroxide precipitation. Therefore, pollution and further dissipation of copper can be avoided using this simple and economic process.

  19. Recovery of copper as zero-valent phase and/or copper oxide nanoparticles from wastewater by ferritization.

    PubMed

    Heuss-Aßbichler, Soraya; John, Melanie; Klapper, Daniel; Bläß, Ulrich W; Kochetov, Gennadii

    2016-10-01

    Recently the focus of interest changed from merely purification of the waste water to recover heavy metals. With the slightly modified ferritization process presented here it is possible to decrease initial Cu(2+) concentrations up to 10 g/l to values <0.3 mg/l. The recovery rates of copper of all experiments are in the rage of 99.98 to almost 100%. Copper can be precipitated as oxide or zero valent metal (almost) free of hydroxide. All precipitates are exclusively of nanoparticle size. The phase assemblage depends strongly on experimental conditions as e.g. reaction temperature, pH-value, initial concentration and ageing time and condition. Three different options were developed depending on the reaction conditions. Option 1.) copper incorporation into the ferrite structure ((Cu,Fe)Fe2O4) and/or precipitation as cuprite (Cu2O) and zero-valent copper, option 2.) copper incorporation into the ferrite structure and/or precipitation as cuprite and/or tenorite (CuO) and option 3.) copper precipitation as tenorite. Ferrite is formed by the oxidation of GR in alkaline solution without additional oxygen supply. The chemistry reaches from pure magnetite up to 45% copper ferrite component. First experiments with wastewater from electroplating industry confirm the results obtained from synthetic solutions. In all cases the volume of the precipitates is extremely low compared to typical wastewater treatment by hydroxide precipitation. Therefore, pollution and further dissipation of copper can be avoided using this simple and economic process. PMID:27290656

  20. 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

  1. 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.

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

    SciTech Connect

    Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; Sun, Shouheng; Pham, Viet Hung

    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.

  3. Structural and magnetic characterization of co-precipitated NixZn1-xFe2O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Tirupanyam, B. V.; Meena, S. S.; Yusuf, S. M.; Babu, Ch. Seshu; Ramakrishna, K. S.; Potukuchi, D. M.; Sastry, D. L.

    2016-06-01

    A series of NixZn1-xFe2O4 (x=0.5, 0.6 and 0.7) ferrite nanoparticles have been synthesized using a co-precipitation technique, in order to understand the doping effect of nickel on their structural and magnetic properties. XRD and FTIR studies reveal the formation of spinel phase of ferrite samples. Substitution of nickel has promoted the growth of crystallite size (D), resulting the decrease of lattice strain (η). It was also observed that the lattice parameter (a) increases with the increase of Ni2+ ion concentration. All particles exhibit superparamagnetism at room temperature. The hyperfine interaction increases with the increase of nickel substitution, which can be assumed to the decrease of core-shell interactions present in the nanoparticles. The Mössbauer studies witness the existence of Fe3+ ions and absence of Fe2+ ions in the present systems. These superparamagnetic nanoparticles are supposed to be potential candidates for biomedical applications. The results are interpreted in terms of microstructure, cation redistribution and possible core-shell interactions.

  4. 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.

  5. 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.

  6. The structure, morphology and magnetic properties of Sr-ferrite powder prepared by the molten-salt method

    NASA Astrophysics Data System (ADS)

    He, Xuemin; Zhong, Wei; Yan, Shiming; Au, Chak-Tong; Lü, Liya; Du, Youwei

    2014-06-01

    Sub-micrometre high-performance Sr-ferrite powder was prepared by a molten-salt method using Na2SO4 as the fluxing agent. In the reaction process, a mixture of superfine powder was pre-sintered at 1150 °C for 3 h and then annealed at 850 °C for 2 h. The as-obtained Sr-ferrite powder is SrFe12O19 with a hexagonal magnetoplumbite structure. We observe that with raising the pre-sintering temperature as well as increasing the annealing temperature and time, there is an enlargement of particle size. We regulated the reaction parameters to optimize the magnetic properties of the Sr-ferrite powder. The structure with the best magnetic properties is quasi-cubic in shape and relatively uniform in size, showing a coercivity of 471.89 kA m-1, a saturation magnetization of 91.51 µWb m kg-1, a remanence ratio of 0.50 and a maximum magnetic energy product of 7.89 kJ m-3. We then studied the effects of particle size, demagnetization factor and magnetocrystalline anisotropy on coercivity. Compared with the conventional ceramic process, the one presented here is more convenient and economical for the production of homogeneous hexagonal ferrite powders of high magnetic performance.

  7. 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.

  8. Preparation and magnetic properties of MgZn and MnZn ferrites

    NASA Astrophysics Data System (ADS)

    Skołyszewska, B.; Tokarz, W.; Przybylski, K.; Kaķol, Z.

    2003-05-01

    Synthesis of magnesium-zinc [(Mg 0.63Zn 0.37)(Mn 0.1Fe 1.8)O 3.85] and manganese-zinc [(Mn 0.55Zn 0.35Fe 0.1)Fe 2O 4] ferrites by solid-state reaction method is described. Brunauer-Emmett-Teller (BET) surface areas of the ferrite powders used for synthesis were 2.63 m 2/g for magnesium-zinc ferrite and 2.86 m 2/g for manganese-zinc ferrite respectively. The dense sintered bodies of MgZn and MnZn ferrites obtained at 1250-1300 °C were characterized by the presence of Fe 2O 3 particles uniformly dispersed through a cross-section. Saturation magnetization and hysteresis loops of MgZn and MnZn ferrites were measured using a vibrating magnetometer for both powdered and sintered samples. The samples were distinguished by small core losses and small coercive forces characteristic for soft magnetic materials. The hysteresis loops width for powdered materials were of the order of 15-35 Oe, whereas for sintered specimens they were less than 1 Oe. The saturation magnetization for powders were different from that for sintered samples. The microstructure, chemical, and phase analyses of powders and sintered bodies of ferrites were conducted by scanning electron microscopy (SEM), by energy dispersion X-ray spectroscopy (EDS), and X-ray diffraction (XRD).

  9. 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

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

    PubMed

    Batoo, Khalid Mujasam; Ansari, Mohammad Shahnawaze

    2012-02-08

    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.

  11. 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.

  12. 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.

  13. Preparation of conducting silver paste with Ag nanoparticles prepared by e-beam irradiation

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    Conducting silver paste was prepared by using Ag nanoparticles which were synthesized by e-beam irradiation method (from KAERI); its conductivity was comparatively determined with Ag nanoparticles which were prepared by thermolysis method (commercial). The silver nanoparticles with the diameter of approximately 150 nm size prepared by e-beam irradiation were mixed with glass frit and sintered for 1 h at 500 °C. It is presumably concluded that the wt% of silver nanoparticle, size distribution and homogenous dispersibility of Ag nanoparticles in the pastes are the critical factors for the high conductivity of the paste. Among the various wt% of silver nanoparticle in the conducting silver pastes, silver paste with 90 wt% of silver nanoparticle has the highest conductivity as 1.6×10 4 S cm -1. This conductivity value is 1.6 times higher than the Ag pastes which were prepared with silver nanoparticles obtained by thermolysis method.

  14. Effect of the Preparation Method on the Oxidation-Reduction Mechanism and the Cation Distribution of Mn-Zn Ferrites

    NASA Astrophysics Data System (ADS)

    Gillot, B.; El Guendouzi, M.

    1993-10-01

    The cation distribution of manganese-zinc ferrite Mn 0.50Zn 0.15Fe 2.05O 4 prepared by a ceramic route and wet method was investigated by derivative thermogravimetry (DTG) and X-ray diffraction analyses. Below about 500°C, these ferrites which are oxidized in cation deficient spinels show an incomplete oxidation of tetrahedral Mn 2+ ions leading to a cation distribution (Zn 2+0.43 Mn 2+0.15Fe 3+0.42) A (Fe 3+1.54Mn 3+0.32 □ 0.14) BO 2-4. With increasing temperature further oxidation of Mn 2+ ions results in the appearance of a rhombohedral phase α-(Fe 2- zMn z)O 3 rich in iron accompanied by a spinel phase containing the totality of zinc.

  15. Effect of Sintering Temperature on the Structural and Dielectric Properties of Zinc Cadmium Ferrites Prepared by Egg-White Technique

    NASA Astrophysics Data System (ADS)

    Dar, M. Abdullah; Siddiqui, W. A.; Alam, M.

    The effect of cadmium substitution and sintering temperature on the microstructure and dielectric properties of nano ZnCdxFe2-xO4 ferrites (x=0.0, 0.05, 0.1, 0.2, 0.3 and 0.5) has been investigated and prepared by egg-white technique. Electrical conductivity and dielectric measurements have been analysed in the frequency range from 100 Hz to 10 MHz. The variation of the real (ɛ‧) and imaginary (ɛ″) part of dielectric constant, AC conductivity (σAC) and loss tangent (tan δ) with frequency has been studied. It follows the Maxwell-Wagner model based on the interfacial polarization in consonance with the Koop's phenomenological theory. It is found that the permittivity of ZnCdxFe2-xO4 ferrites improved and shows a maximum value (~9 × 103) at 100 Hz for the x=0.1 sample.

  16. Preparation and Characterization of Calcium Carbonate Nanoparticles

    NASA Astrophysics Data System (ADS)

    Hassim, Aqilah; Rachmawati, Heni

    2010-10-01

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

  17. 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

  18. Preparation and characterization of porphyrin nanoparticles.

    PubMed

    Gong, Xianchang; Milic, Tatjana; Xu, Chang; Batteas, James D; Drain, Charles Michael

    2002-12-01

    The synthesis, characterization, and stability of porphyrin nanoparticles of 20-200 nm diameter presented herein is general for meso arylporphyrins. The elegance of the method lies in its simplicity. This work shows that the agent used to prevent agglomeration can be covalently attached to the dye forming the particle or be part of the solvent system. It also demonstrates that these and other types of dyes with a range of photonic properties do not need to be prepared by inclusion in external matrices or by designed self-assembly a priori. The matrix may severely limit the functionality of the particles in the former case, and at present this size of particle is difficult to achieve via the latter.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

    Ounnunkad, S.; Winotai, P.

    2006-06-01

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

  2. 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.

  3. Preparations, characterizations and applications of chitosan-based nanoparticles

    NASA Astrophysics Data System (ADS)

    Liu, Chenguang; Tan, Yulong; Liu, Chengsheng; Chen, Xiguang; Yu, Lejun

    2007-07-01

    Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations: emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.

  4. Effect of heat treatment on structural and Mössbauer spectroscopic properties of coprecipitated Mn0.5Ni0.5Fe2O4 ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Srinivas, Ch.; Tirupanyam, B. V.; Meena, S. S.; Babu, Ch. Seshu; Sastry, D. L.

    2015-06-01

    Results obtained in a systamatic study by X-ray diffraction and Mösssbauer spectroscopy on the structural and magnetic properties on Mn0.5Ni0.5Fe2O4 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. 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.

  6. Preparation and characterization of magnetic nanoparticles with chitosan coating

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  7. 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.

  8. 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.

  9. 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.

  10. Study on the preparation of Mn-Zn soft magnetic ferrite powders from waste Zn-Mn dry batteries.

    PubMed

    Peng, Chang-hong; Bai, Ben-shuai; Chen, Yi-feng

    2008-01-01

    Using waste Zn-Mn dry batteries, waste scrap iron and pyrolusite as raw materials, Mn-Zn soft magnetic ferrite powders were prepared through the process of simultaneous leaching, purification and co-precipitation. The experimental results indicated that the leached yields of Fe, Mn and Zn were 92.02%, 96.14% and 98.34%, respectively. The leached liquor was purified through these processes of sulfuration precipitation, fluorination precipitation and double salt precipitation deep purification process. Therefore, high removal yields of impurities could be achieved. Removal yields were as follows: Ca 99.7%, Mg 92.33%, Al 96.48%, Si 63.64%, Cu 99.86%, Pb 98.51%, Cd 53.0% and Ni 78.72%. Among these co-precipitation powders, the average mass content of the main components were Fe 41.41%, Mn 13.92% and Zn 4.49%, and the mass ratio of Fe:Zn:Mn was 69.2:23.3:7.5. Compared with the theoretical prescription (Fe:Mn:Zn=67.3:24.4:8.3), the absolute errors of main components were Fe +1.9%, Mn -1.1% and Zn -0.8%. Because of content impurities in co-precipitation powders (Ca<0.0028%, Mg<0.0053%, Al<0.0084%, SiO(2)<0.0023%, Pb<0.0031% and Cu<0.0010%), the qualities of these gained co-precipitation powders could compete with the demand for the preparation of soft magnetic ferrite. The magnetic properties also demonstrated that the soft magnetic ferrite samples, which were made from the co-precipitation powders prepared by used batteries, had the same qualities as PC30 made by the TDK Company.

  11. 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.

  12. A novel sonication route to prepare anthracene nanoparticles

    SciTech Connect

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

    2004-04-02

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed

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

    2011-11-30

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

  15. 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.

  16. Influence of formulation factors on the preparation of zein nanoparticles.

    PubMed

    Podaralla, Satheesh; Perumal, Omathanu

    2012-09-01

    The main objective of the present study was to investigate the influence of various formulation parameters on the preparation of zein nanoparticles. 6,7-dihydroxycoumarin (DHC) was used as a model hydrophobic compound. The influence of pH of the aqueous phase, buffer type, ionic strength, surfactant, and zein concentration on particle size, polydispersity index, and zeta potential of DHC-loaded zein nanoparticles were studied. Smaller nanoparticles were formed when the pH was close to the isoelectric point of zein. DHC-loaded zein nanoparticles prepared using citrate buffer (pH 7.4) was better than phosphate buffer in preventing particle aggregation during lyophilization. The ionic strength did not have a significant influence on the particle size of DHC-loaded zein nanoparticles. A combination of Pluronic F68 and lecithin in 2:1 ratio stabilized the zein nanoparticles. An increase in zein concentration led to increase in particle size of DHC-loaded zein nanoparticles. The use of optimal conditions produced DHC-loaded nanoparticles of 256 ± 30 nm and an encapsulation efficiency of 78 ± 7%. Overall, the study demonstrated the optimal conditions to prepare zein nanoparticles for drug encapsulation.

  17. 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

  18. 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.

  19. 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.

  20. 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.

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

    PubMed Central

    Bregar, Vladimir B; Lojk, Jasna; Šuštar, Vid; Veranič, Peter; Pavlin, Mojca

    2013-01-01

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

  2. 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

  3. On the Structure and Some Properties of LaCo Co-substituted NiZn Ferrites Prepared Using the Standard Ceramic Technique

    NASA Astrophysics Data System (ADS)

    Niu, Xiaofei; Liu, Xiansong; Huang, Xin; Huang, Kai; Ma, Yuqi; Huang, Feng; Lv, Farui

    2016-04-01

    Zn0.5Ni0.5-xCoxFe2-yLayO4 ferrites (with x=0, 0.02 and y=0, 0.02) were prepared by an industrial method using the standard ceramic technique and sintered at 1,250°C in air. X-ray diffraction (XRD) was used to obtain the phase formation of the NiZn ferrites. The microstructure of ferrites was investigated by scanning electron microscopy (SEM). The XRD reveals that lattice parameter (a) is decreased and a secondary phase (LaFeO3) is formed in the La-Co co-substituted NiZn ferrite sample, meanwhile, the grain size (D) of this sample decreased obviously by observing SEM photographs. Vibrating sample magnetometry (VSM), B-H analyzer, impedance analyzer and electrometer were carried out in order to characterize some properties of the ferrites. This investigation indicates that, La-Co co-substituted NiZn ferrite sample has higher power loss (Pcv) than other samples at low frequency with an increase in coercive field (Hc) and magnetocrystalline anisotropy (K1), a decrease in initial permeability (μi) and saturation magnetization (Ms). However, at high frequency, the power loss of La-Co co-substituted sample is low, which is attributed to high resistivity (ρ), small grain size (D), less number of Fe2+ ions and low porosity (P).

  4. Cobalt ferrite nanoparticles with improved aqueous colloidal stability and electrophoretic mobility

    NASA Astrophysics Data System (ADS)

    Munjal, Sandeep; Khare, Neeraj

    2016-04-01

    We have synthesized CoFe2O4 (CFO) nanoparticles of size ˜ 12.2 nm by hydrothermal synthesis method. To control the size of these CFO nanoparticles, oleic acid was used as a surfactant. The inverse spinel phase of the synthesized nanoparticles was confirmed by X-ray diffraction method. As synthesized oleic acid coated CFO (OA@CFO) nanoparticles has very less electrophoretic mobility in the water and are not water dispersible. These OA@CFO nanoparticles were successfully turned into water soluble phase with a better colloidal aqueous stability, through a chemical treatment using citric acid. The modified citric acid coated CFO (CA@CFO) nanoparticles were dispersible in water and form a stable aqueous solution with high electrophoretic mobility.

  5. 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.

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

    PubMed

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

    2012-08-01

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

  7. 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.

  8. A review on preparation techniques for synthesis of nanocrystalline soft magnetic ferrites and investigation on the effects of microstructure features on magnetic properties

    NASA Astrophysics Data System (ADS)

    Hajalilou, Abdollah; Mazlan, Saiful Amri

    2016-07-01

    Soft magnetic materials have been used in many applications, i.e., electrical and electronic industries, due to their desirable electromagnetic characteristics. The performance of these materials in bulk form, where the size of grains is in micrometer scale, is only limited to a few megahertz frequencies due to their higher conductivity and domain wall resonance. Synthesizing the ferrite particles in nanometer scales before compacting them for sintering would be one way to solve using these materials at higher frequencies. The properties of ferrite depend mainly on the technique and conditions of preparation, which, in turn, affect the cation distribution over the tetrahedral and octahedral sites. Thus, the aim of this study was to introduce some methods used for synthesizing nanocrystalline soft magnetic ferrites. Furthermore, the microstructure features, i.e., grain sizes and porosities, which are influenced by the types of method used for preparation, playing key role on the magnetic properties of the sample, are also highlighted.

  9. Preparation of nanoparticles in reverse microemulsions

    NASA Astrophysics Data System (ADS)

    Tovstun, Sergey A.; Razumov, Vladimir F.

    2011-10-01

    Experimental data and results of theoretical studies dealing with the synthesis of nanoparticles by the condensation of products of chemical reactions in reverse microemulsions are generalized. Attention is focused on the analysis of mechanisms of nanoparticle nucleation and growth. The bibliography includes 252 references.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Preparation of silver nanoparticles at low temperature

    NASA Astrophysics Data System (ADS)

    Mishra, Mini; Chauhan, Pratima

    2016-04-01

    Silver from ancient time is used as antimicrobial agent in the bulk form but now with the advancement in nanotechnology silver in the form of nanoparticles shown potential effect against microbes which make us easy to fight with many diseases plants and animals. In this work silver nanoparticles were synthesized by chemical routes using sodium borohydride as reducing agent at low temperature. The particles were characterized through UV-Visible spectroscopy as well as X-Ray Diffraction. The UV-visible spectra of silver nanoparticles exhibited absorption at 425 cm; the crystallite size of the particles is between 19nm to 39nm. EDAX graph shows two peaks of silver and oxygen. Water absorbed by silver nanoparticles was removed by the calcinations.

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

    PubMed

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

    2015-12-14

    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.

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

    SciTech Connect

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

    2006-05-15

    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. Moessbauer studies on the synthesized nanoparticles suggest that the critical particle size limit for superparamagnetism to be about 25 nm at 293 K.

  17. 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.

  18. 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.

  19. Preparation and characterization of biopolymeric nanoparticles used in drug delivery.

    PubMed

    Ramachandran, Radhika; Shanmughavel, Piramanayagam

    2010-02-01

    Nanotechnology plays an important role in advanced biology and medicine research particularly in the development of potential site-specific delivery systems with lower drug toxicity and greater efficiency. These include microcapsules, liposomes, polymeric microspheres, microemulsions, polymer micelles, hydrogels, solid nanoparticles etc. In the present study, preparation and characterization of biopolymeric gelatin nanoparticles for encapsulating the antimicrobial drug sulfadiazine and its in vivo drug release in phosphate buffer saline (PBS) have been investigated. The nanoparticles prepared by second desolvation process varied in a size range 200 nm and 600 nm with a drug entrapment efficiency of 50% characterized by atomic force microscopy and dynamic light scattering. The drug release from the nanoparticles occurred up to 30% in a controlled manner.

  20. Preparation and characterization of biopolymeric nanoparticles used in drug delivery.

    PubMed

    Ramachandran, Radhika; Shanmughavel, Piramanayagam

    2010-02-01

    Nanotechnology plays an important role in advanced biology and medicine research particularly in the development of potential site-specific delivery systems with lower drug toxicity and greater efficiency. These include microcapsules, liposomes, polymeric microspheres, microemulsions, polymer micelles, hydrogels, solid nanoparticles etc. In the present study, preparation and characterization of biopolymeric gelatin nanoparticles for encapsulating the antimicrobial drug sulfadiazine and its in vivo drug release in phosphate buffer saline (PBS) have been investigated. The nanoparticles prepared by second desolvation process varied in a size range 200 nm and 600 nm with a drug entrapment efficiency of 50% characterized by atomic force microscopy and dynamic light scattering. The drug release from the nanoparticles occurred up to 30% in a controlled manner. PMID:21086757

  1. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  3. 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.

  4. Preparation and evaluation of thiomer nanoparticles via high pressure homogenization.

    PubMed

    Hoyer, Herbert; Schlocker, Wolfgang; Greindl, Melanie; Ostermann, Thomas; Bernkop-Schnürch, Andreas

    2010-01-01

    The aim of this study was to establish and evaluate a high pressure homogenization method for the preparation of thiomer nanoparticles. Particles were formulated by incorporation of the model protein horseradish peroxidase in chitosan-glutathione (Ch-GSH) and poly(acrylic acid)-glutathione (PAA-GSH) via co-precipitation followed by air jet milling. The resulting microparticles were suspended in distilled water using an Ultraturax and subsequently micronized by high pressure homogenization. Finally, resulting particles were evaluated regarding size distribution, shape, zeta potential, drug load, protein activity and release behaviour. The mean particle size after 30 cycles with a pressure of 1500 bar was 538 +/- 94 nm for particles consisting of Ch-GSH and 638 +/- 94 nm for particles consisting of PAA-GSH. Nanoparticles of Ch-GSH had a positive zeta-potential of +1.03 mv, whereas nanoparticles from PAA-GSH had a negative zeta potential of -6.21 mv. The maximum protein load for nanoparticles based on Ch-GSH and based on PAA-GSH was 45 +/- 2% and 37 +/- %, respectively. The release profile of nanoparticles followed a first order release kinetic. Thiolated nanoparticles prepared by a high pressure homogenization technique were shown to be stable and provide controlled drug release characteristics. The preparation method described here might be a useful tool for a more upscaled production of nanoparticulate drug delivery systems. PMID:20367028

  5. Cell outer membrane mimetic chitosan nanoparticles: preparation, characterization and cytotoxicity.

    PubMed

    Zhao, Jing; Liang, Fei; Kong, Lingheng; Zheng, Lina; Fan, Tao

    2015-01-01

    A negatively charged copolymer poly (MPC-co-AMPS) of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-acrylamide-2-methyl propane sulfonic acid (AMPS) was designed and synthesized. Chitosan nanoparticles with cell outer membrane mimetic structure were prepared by electrostatic interaction between the sulfonic acid groups of poly (MPC-co-AMPS) and the protonated amino groups of chitosan. Effects of factors on influencing the particle size, distribution, and stability were investigated. The experimental results showed that cell membrane mimetic chitosan nanoparticles with controllable and homogeneous size ranged from 100 to 300 nm were prepared at the concentration of 0.1-2.0 mg/mL and the charge ratio of 0.5-1.1. Chitosan nanoparticles prepared can exist stably for more than 45 days when placed at 4 °C and pH < 7.5. The cytotoxicity of the chitosan nanoparticles reduced significantly after surface modification with cell membrane mimetic structure, meeting the basic requirements of biomedical materials. The results suggest cell membrane mimetic chitosan nanoparticles prepared with polyanion and polycation obtain good biological compatibility and immune stealth ability, which has important academic significance and great application prospects.

  6. Preparation and Properties of Various Magnetic Nanoparticles

    PubMed Central

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

    2009-01-01

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

  7. 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.

  8. Effect of Yb substitution on room temperature magnetic and dielectric properties of bismuth ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Remya, K. P.; Amirthapandian, S.; Manivel Raja, M.; Viswanathan, C.; Ponpandian, N.

    2016-10-01

    Effect of the Yb dopant on the structural, magnetic, and electrical properties of the multiferroic BiFeO3 have been studied. The structural properties of sol-gel derived Bi1-xYbxFeO3 (x = 0.0, 0.1, and 0.2) nanoparticles reveal the formation of a rhombohedrally distorted perovskite in XRD and a reduction in the average grain size have been observed with an increase in the Yb concentration. Microstructural studies exhibited the formation of sphere like morphology with decreasing particle size with increase in the dopant concentration. The effective doping also resulted in larger magnetization as well as coercivity with the maximum of 257 Oe and 1.76 emu/g in the Bi0.8Yb0.2FeO3 nanoparticles. Ferroelectric as well as dielectric properties of the nanoparticles were also improved on doping. The best results were obtained for the BiFeO3 nanoparticles having Yb concentration x = 0.2.

  9. Colossal resistivity with diminished tangent loss in Zn-Ni ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Younas, M.; Atif, M.; Nadeem, M.; Siddique, M.; Idrees, M.; Grossinger, R.

    2011-08-01

    We have investigated the electrical and magnetic response of the sol-gel synthesized ZnxNi1-xFe2O4 (x = 0.0, 0.5 and 1) nanoparticles. The ratio of A-site sextet intensity to that of B-site sextet is featured in terms of divergence in coordination of Fe3+ ions from four-fold (A-site) to six-fold (B-site). Canted spin structure and weakening of Fe3+(A)-Fe3+(B) interactions at the surface of the nanoparticles assign the reduced value of room temperature magnetization in these nanoparticles. Shift of the blocking temperature with Zn content is ascribed to the change in the magnetic anisotropy. Colossal resistivity and reduced dielectric constant are discussed on the basis of dangling bond, superparamagnetic character, canted spin structure and polarizability of the cations. Diminished tangent loss is stipulated in terms of decrease in magnetocrystalline anisotropy and collapse of long-range magnetic order. We report colossal resistivity (i.e. 3.15 × 109 Ω cm), reduced dielectric constant (3.97) and diminished tangent loss (0.07) for Ni0.5Zn0.5Fe2O4 nanoparticles.

  10. 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).

  11. Effect of Mo substitution on structural and magnetic properties of Zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Heiba, Zein K.; Mohamed, Mohamed Bakr; Wahba, Adel Maher

    2016-03-01

    Nano ferrite ZnFe2-xMoxO4 (x = 0.0, 0.1, 0.2, and 0.3) samples were synthesized by using citrate method. The phase purity and the structure parameters were studied using X-ray diffraction, FT-IR spectroscopy, and magnetic measurements. Rietveld analysis of X-ray diffraction data revealed that Mo doping ZnFe2O4 changes the degree of inversion of Zn2+ cations. The oxidation state of Mo was studied by using FTIR analysis. Mo doped ZnFe2O4 has a ferromagnetic properties. The magnetization decreases by the replacement of Fe3+ ions by non-magnetic Mo3+ ions. Mo doped ZnFe2O4 samples have a very small coercive field (Hc), which changes depending on the amount of Mo in the sample and reach its maximum value for ZnFe1.7Mo0.3O4. Cation distribution is proposed in an attempt to explain the experimental results of XRD, IR, and VSM data. The direct proportion between the coercive field and the Fe2+ content in the samples was studied in detailed.

  12. Preparation of platinum nanoparticle catalyst for propane dehydrogenation.

    PubMed

    Li, Jun; Wang, Jun; Ma, Zhanhua; Sun, Lanyi; Hu, Yangdong

    2014-09-01

    Supported Pt nanoparticle catalysts were prepared by combing a chemical reduction method with an ultrasonic sonication loading method. Several techniques including transmission electron microscopy (TEM), nitrogen sorption technique and pyridine adsorption Fourier-transform infrared (Py-IR) were applied to characterize the physicochemical properties of these catalysts. The catalytic performance of catalysts was evaluated in the dehydrogenation of propane. The influence of the preparation method of Pt nanoparticles, the ratio of Polyvinyl Pyrrolidone (PVP) to Pt, loading method and different supports on the catalytic performance was investigated. PVP is useful for controlling the size of Pt nanoparticles and a PVP/Pt ratio of 15 is favorable to achieve a good catalytic performance. NaBH4 reduction is better than ethanol refluxing in preparing Pt nanoparticles. The ultrasonic sonication is effective to load the Pt nanoparticles onto the support channels. The mesoporous alumina proved to be a good catalyst support due to its high surface area and unique pore structure. PMID:25924358

  13. 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

  14. 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.

  15. 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.

  16. Effects of preparation conditions on the physical properties of nickel ferrite thin films

    NASA Astrophysics Data System (ADS)

    Belliveau, Hillary; Bonilla, Manuel; McArdle, Patrick; Miller, Casey

    2014-03-01

    The effects of the deposition temperature, pressure, and oxygen partial pressure were investigated on the structural, electrical, and magnetic properties of nickel ferrite (NiFe2O4) thin films grown by magnetron sputtering. The samples were grown on Si (100), Si (100) with 500nm of amorphous SiO2, and on MgO (100) substrates. Increasing the deposition temperature allowed the NiFe2O4 (004) XRD peak to appear at higher oxygen partial pressures. Between films of the same oxygen pressure, increasing the deposition temperature reduced the FWHM and increased the intensity of the NiFe2O4 (004) XRD peak. The films were 800 to 1000nm thick as measured by profilometry. Increasing the oxygen partial pressure reduces the intensity of the (004) NiFe2O4 XRD peak, and allows us to tune the material from a conducting material (rho = 114 microOhm*cm at T =220K) to an insulating one (rho = 2475 Ohm*cm at T =220K). The resistivity at 220K decreased as the deposition temperature was increased for films grown at the same oxygen partial pressure. The magnetic properties were investigated with magneto-optical Kerr effect and vibrating sample magnetometry. Supported by NSF-ECCS.

  17. 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.

  18. 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…

  19. 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).

  20. 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

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

    PubMed

    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 Fe(3+)/Fe(2+) 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 m(2 )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

  2. 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.

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

    PubMed

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

    2016-07-04

    The Photo-Fenton reaction is an advanced technology to eliminate organic pollutants in environmental chemistry. Moreover, the conversion rate of Fe(3+)/Fe(2+) 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 m(2 )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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    NemÅ£anu, Monica R.; Braşoveanu, Mirela; Iacob, Nicuşor

    2014-11-01

    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 ΔEab (total color difference) could characterize the nanoparticles with respect of their concentration. Hue angle ho was correlated to the particle size distribution. Experimental data of the irradiated samples were also subjected to factor analysis using principal component extraction and varimax rotation in order to reveal the relation between dependent variables and independent variables and to reduce their number. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those produced by chemical reduction method. Therefore, the electron beam irradiation is effective for preparation of silver nanoparticles using starch aqueous solution as dispersion medium.

  6. 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.

  7. 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.

  8. Systematic study on the preparation of BSA nanoparticles.

    PubMed

    Galisteo-González, F; Molina-Bolívar, J A

    2014-11-01

    Albumins, in the form of nanoparticles, are increasingly used as drug carriers in the medical field, and the size effect of these nanomaterials is of major importance since it may affect their bioavailability and the in vivo behaviour after intravenous injection. This research provides a comprehensive study on the preparation of BSA nanoparticles, based on a simple coacervation method, with suitable size, size distribution, and surface charge for drug-delivery applications. Numerous experimental variables were examined in order to characterize their impact on nanoparticle size, distribution, electrophoretic mobility, and yield. Particle size was controlled by adjusting self-assembly phenomena of the protein molecules, which was affected by preparation conditions including BSA content, pH, and ionic strength (a parameter that strongly influences nanoparticle formation but surprisingly has not been previously studied in detail). Small particles with a narrow size distribution were obtained under experimental conditions where the repulsion between BSA molecules was high, i.e. at pH values far from the isoelectric point of the protein and low salt concentration. Changes in temperature, volume, and rate of addition of the dehydrating agent (ethanol) also affect nanoparticle characteristics, as they influence the nucleation rate and particle growth. The effect of these experimental conditions on the quantity of protein still dissolved in the aqueous phase after desolvation (i.e. the yield of BSA nanoparticles) was also studied. Nanoparticles surface charge was modulated with the extension of cross-linking. Finally, long-term colloidal stability of samples was evaluated after 2 months of storage.

  9. Preparation and characterization of Au nanoparticles capped with mercaptocarboranyl clusters.

    PubMed

    Cioran, Ana M; Teixidor, Francesc; Krpetić, Željka; Brust, Mathias; Viñas, Clara

    2014-04-01

    The preparation of 3-4 nm and 10 nm gold nanoparticles capped with neutral carborane-based mercaptocarboranes, via two different preparative routes, is reported. The resulting boron-enriched nanomaterials exhibit complete dispersibility in water, opening the way for the use of these monolayer protected clusters (MPCs) in medical applications, such as boron neutron capture therapy (BNCT). These newly prepared MPCs have been characterized by FTIR, (1)H and (11)B NMR spectroscopy, UV-visible, centrifugal particle sizing (CPS), and, in some cases, inductively coupled plasma atomic emission spectrometry (ICP-AES). Water dispersibility exhibited by these MPCs allowed the study of the cellular uptake by HeLa cells.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

    Wang, Wenjie; Zang, Chongguang; Jiao, Qingjie

    2015-03-01

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

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

    PubMed

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

    2015-06-01

    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. PMID:25867626

  13. Radio-frequency-heating capability of silica-coated manganese ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Qiu, Qing-Wei; Xu, Xiao-Wen; He, Mang; Zhang, Hong-Wang

    2015-06-01

    MnFe2O4 nanoparticles (NPs) with various sizes and tight size-distribution were synthesized by a chemical solution-phase method. The as-synthesized NPs were coated with a silica shell of 4 nm-5 nm in thickness, enabling the water-solubility and biocompatibility of the NPs. The MnFe2O4 NPs with a size of less than 18 nm exhibit superparamagnetic behavior with high saturated magnetization. The capacity of the heat production was enhanced by increasing particle sizes and radio frequency (RF) field strengths. MnFe2O4/SiO2 NPs with 18-nm magnetic cores showed the highest heat-generation ability under an RF field. These MnFe2O4/SiO2 NPs have great potentiality to cancer treatments, controlled drug releases, and remote controls of single cell functions.

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

    PubMed

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

    2015-06-01

    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.

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

    PubMed

    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

    2016-06-24

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  17. 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

  18. 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.

  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. 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.

  1. 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

  2. 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.

  3. Preparation, structural and morphological studies of Ni doped titania nanoparticles.

    PubMed

    Rajamannan, B; Mugundan, S; Viruthagiri, G; Shanmugam, N; Gobi, R; Praveen, P

    2014-07-15

    TiO2 nanoparticles doped with different weight percentages (4%, 8%, 12% and 16%) of nickel contents were prepared by a modified sol-gel method using Titanium tetra iso propoxide and nickel nitrate as precursors and 2-propanol as a solvent. X-ray diffraction studies show that the as prepared and annealed products show anatase structure with average particle sizes running between of 8 and 16 nm. FTIR results demonstrate the presence of strong chemical bonding at the interface of TiO2 nanoparticles. The optical properties of bare and doped samples were carried out using UV-DRS and photoluminescence measurements. The surface morphology and the element constitution of the nickel doped TiO2 nanoparticles were studied by scanning electron microscope attached with energy dispersive X-ray spectrometer arrangement. The non linear optical properties of the products were confirmed by Kurtz second harmonic generation (SHG) test and the output power generated by the nanoparticle was compared with that of potassium di hydrogen phosphate (KDP).

  4. Preparation, structural and morphological studies of Ni doped titania nanoparticles

    NASA Astrophysics Data System (ADS)

    Rajamannan, B.; Mugundan, S.; Viruthagiri, G.; Shanmugam, N.; Gobi, R.; Praveen, P.

    2014-07-01

    TiO2 nanoparticles doped with different weight percentages (4%, 8%, 12% and 16%) of nickel contents were prepared by a modified sol-gel method using Titanium tetra iso propoxide and nickel nitrate as precursors and 2-propanol as a solvent. X-ray diffraction studies show that the as prepared and annealed products show anatase structure with average particle sizes running between of 8 and 16 nm. FTIR results demonstrate the presence of strong chemical bonding at the interface of TiO2 nanoparticles. The optical properties of bare and doped samples were carried out using UV-DRS and photoluminescence measurements. The surface morphology and the element constitution of the nickel doped TiO2 nanoparticles were studied by scanning electron microscope attached with energy dispersive X-ray spectrometer arrangement. The non linear optical properties of the products were confirmed by Kurtz second harmonic generation (SHG) test and the output power generated by the nanoparticle was compared with that of potassium di hydrogen phosphate (KDP).

  5. Processing and application of nanosized ferrite powders

    SciTech Connect

    Drofenik, M.; Rozman, M.

    1995-09-01

    Crystalline MnZn ferrite of nanosize was prepared by the hydrothermal synthesis. The pH value of the starting suspension was found to influence substantially the ferrite composition. The nanosized ferrite powder is very sensitive to oxidation and sinters to nearly theoretical density in nitrogen. The correlation between the eddy-current loss and microstructure is given.

  6. Preparation of nanoporous titania spherical nanoparticles

    NASA Astrophysics Data System (ADS)

    Shiba, Kota; Sato, Soh; Matsushita, Takayuki; Ogawa, Makoto

    2013-03-01

    Preparation of nanoporous titania particles from well-defined titania-octadecylamine (titania-ODA) hybrid spherical particles with 450 nm in size, which were prepared by the method reported previously (Chem. Commun., 2009, pp. 6851-6853 [39]; RSC Adv., 2012, vol. 2, pp. 1343-1349 [40]), was studied. ODA was removed by solvent extraction with acidic ethanol to obtain nanoporous titania particles and subsequent calcination led to the formation of nanoporous titania particles with the nanopore size ranging from 2 to 4 nm depending on the calcination temperature. The as-synthesized titania was amorphous and was transformed into anatase (at around 300 °C) and rutile (at around 600 °C) by the heat treatment. The phase transition behavior was discussed in comparison with that of as-synthesized titania-ODA particles without ODA removal. Spherical particles of titania-ODA hybrids with 70 nm in size were also transformed into nanoporous titania particles composed of anatase crystallites by the washing and calcination at 500 °C for 1 h.

  7. Indomethacin-loaded poly(butylcyanoacrylate) nanoparticles: preparation and characterization.

    PubMed

    Liu, Haiyan; Chen, Jinchun

    2009-01-01

    This paper describes a method to prepare indomethacin-loaded poly(butylcyanoacrylate) (PBCA) nanoparticles based on the anionic polymerization procedure, often used in the synthesis of poly(alkylcyanoacrylate) (PACA) nanoparticles for drug delivery. A detailed investigation into the capability of the polymeric nanoparticles to load this drug is discussed, along with the effect of the technique parameters on characteristics of the nanoparticles. The results indicated that indomethacin-loaded PBCA nanoparticles showed a particle size distribution that could be successfully exploited for the formulation of colloidal pharmaceutical systems. The particles were predominantly less than 200 nm in size with a negative charge, and rather stable when pH was adjusted to neutral. In addition, X-ray diffraction experiments revealed that the drug would be molecularly dispersed in the polymers in an amorphous state and crystalline with very small size. In vitro drug release revealed that indomethacin incorporation and/or adsorption led to a rapid drug release followed by a slower release in biological phosphate buffer and that the release rate decreased with increasing indomethacin content in the particle.

  8. Preparation of platinum nanoparticles in liquids by laser ablation method

    NASA Astrophysics Data System (ADS)

    Binh Nguyen, The; Dinh Nguyen, Thanh; Nguyen, Quang Dong; Trinh Nguyen, Thi

    2014-09-01

    Platinum (Pt) nanoparticles were prepared in solutions of ethanol and TSC (trisodium citrate—Na3C6H5O7.nH2O) in water by laser ablation method using Nd:YAG laser. The role of laser fluence, laser wavelength and concentration of surfactant liquids in laser ablation process were investigated. The morphology, size distribution and optical properties of the Pt nanoparticles (NPs) were observed by transmission electron microscopy (TEM), UV-vis spectrometer and x-ray diffraction measurements. The average diameter of Pt NPs prepared in ethanol and TSC solutions ranges around 7-9 nm and 10-12 nm, respectively. The results showed advantages of the laser ablation method.

  9. Preparation of concentrated colloids of gold core-silica shell nanoparticles for biomedical applications.

    PubMed

    Park, Yeon-Su

    2012-01-01

    Encapsulation of gold nanoparticles within a silica shell is highly beneficial to the preparation of highly concentrated gold nanoparticles that can strongly absorb X-ray and hence be used as an X-ray contrast agent. This chapter describes a method for preparing highly concentrated colloidal gold nanoparticles suitable for an X-ray contrast agent application. It describes specific details of procedures for preparing spherical gold nanoparticles, forming thin silica shell on each gold nanoparticle, and enriching the silica-encapsulated gold nanoparticles.

  10. A solution for the preparation of hexagonal M-type SrFe12O19 ferrite using egg-white: Structural and magnetic properties

    NASA Astrophysics Data System (ADS)

    Li, Tingting; Li, Yang; Wu, Ruonan; Zhou, Han; Fang, Xiaochen; Su, Shubing; Xia, Ailin; Jin, Chuangui; Liu, Xianguo

    2015-11-01

    A new sol-gel route using egg-white as the binder of metal ions, is developed to prepare hexagonal M-type SrFe12O19 ferrite in this study, and the effects of different atomic ratio of Sr and Fe (Sr/Fe), sintering temperature (Ts) and usage of egg-white (Mew) on the phase formation, morphology and magnetic properties of specimens are studied. It is found that the single-phase SrFe12O19 ferrite only can be obtained under a Sr/Fe of 1:8 and a Ts between 1000 °C and 1300 °C. The magnetic properties of specimens are also obviously affected by the different Sr/Fe and Ts, primarily due to the emergency of impurities. The Mew has an obvious impact on the crystallinity of specimens, which consequently affects their magnetic properties. In our study, the optimum conditions to prepare the single-phase SrFe12O19 ferrite are Sr/Fe=1:8, Mew= 3 g and Ts =1200 °C.

  11. 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

  12. 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.

  13. Surfactant-free small Ni nanoparticles trapped on silica nanoparticles prepared by pulsed laser ablation in liquid

    NASA Astrophysics Data System (ADS)

    Mafuné, Fumitaka; Okamoto, Takumi; Ito, Miho

    2014-01-01

    Small Ni nanoparticles supported on silica nanoparticles were formed by pulsed laser ablation in liquid. Water dispersing surfactant-free silica particles was used here as a solvent, and a bulk Ni metal plate as a target. The nanoparticles formed by laser ablation in water were readily stabilized by the silica particles, whereas Ni nanoparticles prepared in water without silica were found to be precipitated a few hours after aggregation into 5-30 nm particles. The nanoparticles were characterized by TEM, dark-field STEM and optical absorption spectroscopy, which indicated that small 1-3 nm Ni nanoparticles were adsorbed on the surface of silica.

  14. 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.

  15. Enzymatic polymerizations using surfactant microstructures and the preparation of polymer-ferrite composites

    SciTech Connect

    Kommareddi, N.S.; Tata, M.; Karayigitoglu, C.

    1995-12-31

    Horseradish peroxidase has been used as a biocatalyst to synthesize a polymeric material from alkyl-substituted phenols. The synthesis is carried out in a surfactant-based microemulsion environment, with the monomer partitioned at the oil/water interface. The spherical nature of the microemulsion nanodroplets may be acting as a template for the polymer synthesis. The resultant polymer particles are spherical and typically in the submicron size range. The characteristics of the morphology development are described. The templating effect of the surfactant environment becomes more evident when the polymer particles are fully dissolved in a suitable solvent and refolded in the presence of surfactant. Interestingly, submicron-sized spherical particles are obtained only in the presence of surfactant, and particles of arbitrary morphology are seen in the absence of surfactant. Aspects of morphology development leading to the preparation of polymer-iron oxide composites are described.

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    Thin films of Ba2Zn2Fe12O22 (Y) hexaferrite were prepared through the chemical solution deposition method on SrTiO3(1 1 1) (ST) single crystal substrates using epitaxial SrFe12O19 (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 SrTiO3 substrate and both hexaferrite phases.

  17. 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.

  18. 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.

  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. 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.

  1. 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.

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

    SciTech Connect

    Hidayat, Darmawan; Purwanto, Agus; Wang, Wei-Ning; Okuyama, Kikuo

    2010-02-15

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

  3. Preparation and Properties of FeCo Nanoparticles

    SciTech Connect

    Zabransky, K.; David, B.; Pizurova, N.; Schneeweiss, O.; Zboril, R.; Maslan, M.

    2010-07-13

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

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

    NASA Astrophysics Data System (ADS)

    Yadav, Raghvendra Singh; Havlica, Jaromir; Hnatko, Miroslav; Šajgalík, Pavol; Alexander, Cigáň; Palou, Martin; Bartoníčková, Eva; Boháč, Martin; Frajkorová, Františka; Masilko, Jiri; Zmrzlý, Martin; Kalina, Lukas; Hajdúchová, Miroslava; Enev, Vojtěch

    2015-03-01

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

  5. 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

  6. 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.

  7. Experimental demonstration of all-optical weak magnetic field detection using beam-deflection of single-mode fiber coated with cobalt-doped nickel ferrite nanoparticles.

    PubMed

    Pradhan, Somarpita; Chaudhuri, Partha Roy

    2015-07-10

    We experimentally demonstrate single-mode optical-fiber-beam-deflection configuration for weak magnetic-field-detection using an optimized (low coercive-field) composition of cobalt-doped nickel ferrite nanoparticles. Devising a fiber-double-slit type experiment, we measure the surrounding magnetic field through precisely measuring interference-fringe yielding a minimum detectable field ∼100  mT and we procure magnetization data of the sample that fairly predicts SQUID measurement. To improve sensitivity, we incorporate etched single-mode fiber in double-slit arrangement and recorded a minimum detectable field, ∼30  mT. To further improve, we redefine the experiment as modulating fiber-to-fiber light-transmission and demonstrate the minimum field as 2.0 mT. The device will be uniquely suited for electrical or otherwise hazardous environments.

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

    NASA Astrophysics Data System (ADS)

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

    2003-05-01

    Barium ferrite powders were successfully synthesized by microwave-induced combustion. The magnetic properties of barium ferrite powders with various Fe/Ba ratios varying from 11 to 12 annealed at various temperatures in the range of 850-1050°C were determined. The resultant powders were investigated by X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), differential thermal analyzer/thermogravimeter (DTA/TG), and surface area measurement. Microwave-heated barium ferrite with an Fe/Ba ratio of 11 and annealed at 1000°C for 2 h exhibited optimum magnetic properties for magnetic recording applications, a saturation magnetization of 66 emu/g and an intrinsic coercive force of 2100 Oe. The microwave-heated barium ferrite powders with various Fe/Ba ratios annealed at various temperatures had particles size ranging from 40 to 90 nm. Thus, the fine control of crystal growth by varying the annealing temperature can be exploited for the production of fine magnetic powders of various sizes for a variety of practical applications.

  9. 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.

  10. 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. PMID:26858157

  11. 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.

  12. 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

    2016-01-01

    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. PMID:27104514

  13. Preparation of iron oxide-entrapped chitosan nanoparticles for stem cell labeling.

    PubMed

    Chaleawlert-Umpon, Saowaluk; Mayen, Varissaporn; Manotham, Krissanapong; Pimpha, Nuttaporn

    2010-01-01

    This study intended to prepare iron oxide nanoparticle-entrapped chitosan (CS) nanoparticles for stem cell labeling. The nanoparticles were synthesized by polymerizing iron oxide nanoparticle-associated methacrylic acid monomer in the presence of CS. TEM revealed that the well-defined iron oxide nanoparticles were successfully encapsulated inside the CS nanoparticles. The effect of CS at different [NH(2)]/[COOH] molar ratios on particle size, surface charge, thermal stability and magnetic properties was determined systematically. Internalization and localization of the coated nanoparticles were evaluated by atomic absorption spectrometry and confocal laser scanning microscopy. The Kusa O cell line was chosen as a stem cell model. Interestingly, the uptake of iron oxide-entrapped CS nanoparticles was remarkably enhanced under magnetization and the nanoparticles were mostly located inside cellular compartments. It can be concluded that the iron oxide-entrapped CS nanoparticles have a strong potential for stem cell labeling. PMID:20537238

  14. 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.

  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. 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. PMID:26686185

  17. 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%).

  18. Biological preparation of chitosan nanoparticles and its in vitro antifungal efficacy against some phytopathogenic fungi.

    PubMed

    Sathiyabama, M; Parthasarathy, R

    2016-10-20

    The aim of the present study was to prepare Chitosan nanoparticles through biological method with high antifungal activities. Chitosan nanoparticles were prepared by the addition of anionic proteins isolated from Penicillium oxalicum culture to chitosan solutions. The formation of chitosan nanoparticles was preliminary confirmed by UV-vis spectrophotometric analysis. The physico-chemical properties of the chitosan nanoparticles were determined by size and zeta potential analysis, FTIR analysis, HRTEM and XRD pattern. The chitosan nanoparticles were evaluated for its potential to inhibit the growth of phytopathogens viz., Pyricularia grisea, Alternaria solani, Fusarium oxysporum. It is evident from our results that chitosan nanoparticles inhibit the growth of phytopathogens tested. Chitosan nanoparticle treated chickpea seeds showed positive morphological effects such as enhanced germination%, seed vigor index and vegetative biomass of seedlings. All these results indicate that chitosan nanoparticle can be used further under field condition to protect various crops from the devastating fungal pathogens as well as growth promoters.

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

    PubMed

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

    2014-10-01

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

  20. Biological preparation of chitosan nanoparticles and its in vitro antifungal efficacy against some phytopathogenic fungi.

    PubMed

    Sathiyabama, M; Parthasarathy, R

    2016-10-20

    The aim of the present study was to prepare Chitosan nanoparticles through biological method with high antifungal activities. Chitosan nanoparticles were prepared by the addition of anionic proteins isolated from Penicillium oxalicum culture to chitosan solutions. The formation of chitosan nanoparticles was preliminary confirmed by UV-vis spectrophotometric analysis. The physico-chemical properties of the chitosan nanoparticles were determined by size and zeta potential analysis, FTIR analysis, HRTEM and XRD pattern. The chitosan nanoparticles were evaluated for its potential to inhibit the growth of phytopathogens viz., Pyricularia grisea, Alternaria solani, Fusarium oxysporum. It is evident from our results that chitosan nanoparticles inhibit the growth of phytopathogens tested. Chitosan nanoparticle treated chickpea seeds showed positive morphological effects such as enhanced germination%, seed vigor index and vegetative biomass of seedlings. All these results indicate that chitosan nanoparticle can be used further under field condition to protect various crops from the devastating fungal pathogens as well as growth promoters. PMID:27474573

  1. 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

    2013-01-01

    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

  2. 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.

  3. 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.

  4. 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.

  5. Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.

    PubMed

    Zhu, Qinshu; Wang, Yan; Zhou, Min; Mao, Chun; Huang, Xiaohua; Bao, Jianchun; Shen, Jian

    2012-05-01

    The anionic polyurethane nanoparticles (APU-NPs) were obtained by an emulsion polymerization method. It was found that the average size of the prepared APU-NPs is about 84 nm, and the APU-NPs have zeta-potential of -38.9 mV. The bulk characterization of synthesized APU-NPs was investigated by FTIR. The blood compatibility of APU-NPs was characterized by in vitro for coagulation tests, complement activation, platelet activation, cytotoxicity experiments, and hemolysis assay. The results showed that the APU-NPs synthesized in this paper are blood compatible with low level of cell cytotoxicity, and the results were significant for their potential use in vivo. PMID:22852346

  6. Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.

    PubMed

    Zhu, Qinshu; Wang, Yan; Zhou, Min; Mao, Chun; Huang, Xiaohua; Bao, Jianchun; Shen, Jian

    2012-05-01

    The anionic polyurethane nanoparticles (APU-NPs) were obtained by an emulsion polymerization method. It was found that the average size of the prepared APU-NPs is about 84 nm, and the APU-NPs have zeta-potential of -38.9 mV. The bulk characterization of synthesized APU-NPs was investigated by FTIR. The blood compatibility of APU-NPs was characterized by in vitro for coagulation tests, complement activation, platelet activation, cytotoxicity experiments, and hemolysis assay. The results showed that the APU-NPs synthesized in this paper are blood compatible with low level of cell cytotoxicity, and the results were significant for their potential use in vivo.

  7. 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.

  8. Preparation of controlled gold nanoparticle aggregates using a dendronization strategy.

    PubMed

    Paez, Julieta I; Coronado, Eduardo A; Strumia, Miriam C

    2012-10-15

    In this work, a dendronization strategy was used to control interparticle spacing and the optical properties of gold nanoparticle (NP) aggregates in aqueous media. To achieve this goal, two dendritic disulfides bearing different functionalities on their periphery were synthesized and used as ligands to dendronize gold NPs. The dendronized NPs then undergo aggregation; this process was followed by UV-vis spectroscopy, dynamic light scattering (DLS), and transmission electronic microscopy (TEM) measurements and correlated with Generalized Mie Theory electrodynamics calculations. For comparison, NP functionalization was also studied using a nondendritic ligand. It was found that the use of dendritic disulfides allows for the preparation of controlled NP aggregates. This study demonstrates how different dendronization parameters, such as disulfide concentration, temperature, time and nature of the ligand (dendritic vs nondendritic), determine the control exerted over the size and stability of the NP aggregates.

  9. 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.

  10. Preparation and Characterization of PEG-albumin-curcumin Nanoparticles Intended to Treat Breast Cancer

    PubMed Central

    Thadakapally, R.; Aafreen, Arshiya; Aukunuru, J.; Habibuddin, M.; Jogala, S.

    2016-01-01

    The aim of present research was to prepare novel serum stable long circulating polymeric nanoparticles for curcumin with a modification to the well known and novel nanoparticle albumin bound technology. polyethylene glycol-albumin-curcumin nanoparticles were prepared using serum albumin and poly ethylene glycol using desolvation technique. Nanoparticles were characterized for encapsulation efficiency, particle size and surface morphology. Drug excipient compatibility was determined using fourier transform infrared spectroscopy. Physical state of the drug in the formulations was known by differential scanning colorimetry. In vitro release and solubility of the drug from nanoparticles were determined. In vivo Drug release, tissue uptake and kupffer cell uptake was determined with optimized nanoformulation in rats after intravenous administration. Cell viability assay was determined using breast cancer cell line MD-MB-231. Entrapment efficiency for prepared nanoparticle was above 95%. The polyethylene glycol-albumin-curcumin nanoparticles exhibited an interesting release profile with small initial burst followed by slower and controlled release. Solubility of the drug from the formulation was increased. A sustained release of drug from nanoparticles was observed for 35 days in both in vitro and in vivo studies with the optimized formulation. Polyethylene glycol-albumin-curcumin nanoparticles showed lesser liver and kupffer cell uptake as compared to that of curcumin-albumin nanoparticles suggesting the bestowment of stealthness to nanoparticles with pegylation. Also, the antiproliferative activity of polyethylene glycol-albumin-curcumin nanoparticle formulation was more as compared to native curcumin. Polyethylene glycol-albumin-curcumin nanoparticles thus developed can be conveniently used in breast cancer with improved efficacy compared to conventional therapies and as an alternate to nanoparticle albumin bound technology which is used in producing Abraxane, albumin

  11. Preparation and Characterization of PEG-albumin-curcumin Nanoparticles Intended to Treat Breast Cancer.

    PubMed

    Thadakapally, R; Aafreen, Arshiya; Aukunuru, J; Habibuddin, M; Jogala, S

    2016-01-01

    The aim of present research was to prepare novel serum stable long circulating polymeric nanoparticles for curcumin with a modification to the well known and novel nanoparticle albumin bound technology. polyethylene glycol-albumin-curcumin nanoparticles were prepared using serum albumin and poly ethylene glycol using desolvation technique. Nanoparticles were characterized for encapsulation efficiency, particle size and surface morphology. Drug excipient compatibility was determined using fourier transform infrared spectroscopy. Physical state of the drug in the formulations was known by differential scanning colorimetry. In vitro release and solubility of the drug from nanoparticles were determined. In vivo Drug release, tissue uptake and kupffer cell uptake was determined with optimized nanoformulation in rats after intravenous administration. Cell viability assay was determined using breast cancer cell line MD-MB-231. Entrapment efficiency for prepared nanoparticle was above 95%. The polyethylene glycol-albumin-curcumin nanoparticles exhibited an interesting release profile with small initial burst followed by slower and controlled release. Solubility of the drug from the formulation was increased. A sustained release of drug from nanoparticles was observed for 35 days in both in vitro and in vivo studies with the optimized formulation. Polyethylene glycol-albumin-curcumin nanoparticles showed lesser liver and kupffer cell uptake as compared to that of curcumin-albumin nanoparticles suggesting the bestowment of stealthness to nanoparticles with pegylation. Also, the antiproliferative activity of polyethylene glycol-albumin-curcumin nanoparticle formulation was more as compared to native curcumin. Polyethylene glycol-albumin-curcumin nanoparticles thus developed can be conveniently used in breast cancer with improved efficacy compared to conventional therapies and as an alternate to nanoparticle albumin bound technology which is used in producing Abraxane, albumin

  12. Preparation of human immune effector T cells containing iron-oxide nanoparticles.

    PubMed

    Iida, Hironori; Takayanagi, Kosuke; Nakanishi, Takuya; Kume, Akiko; Muramatsu, Kouji; Kiyohara, Yoshio; Akiyama, Yasuto; Osaka, Tetsuya

    2008-12-15

    Preparation of human immune T cells containing iron-oxide nanoparticles was carried out for the development of magnetically mediated immunotherapy. Peripheral blood lymphocytes (PBLs) after the incubation with magnetite nanoparticles were found to contain measurable ferric ions, which suggested the incorporation of magnetite nanoparticles. Transmission electron microscopic (TEM) study indicated that the incorporation of magnetite nanoparticles was mediated by endocytosis of PBLs. Furthermore, the effects of dosages and diameter of magnetite nanoparticles on the magnetite incorporation were investigated, and it was demonstrated that the increase in dosage promoted the incorporation of nanoparticles and the uptake into PBLs was more effective for magnetite nanoparticles, which formed smaller aggregations in medium. Finally, the demonstration of magnetite incorporation into enriched T cells and tumor antigen-specific cytotoxic T lymphocyte (CTL) line promises the achievement of magnetically mediated immunotherapy with tumor-specific CTLs containing magnetic nanoparticles.

  13. Control of Colloid Surface Chemistry through Matrix Confinement: Facile Preparation of Stable Antibody Functionalized Silver Nanoparticles

    PubMed Central

    Skewis, Lynell R.; Reinhard, Björn M.

    2010-01-01

    Here we describe a simple yet efficient gel matrix assisted preparation method which improves synthetic control over the interface between inorganic nanomaterials and biopolymers and yields stable biofunctionalized silver nanoparticles. Covalent functionalization of the noble metal surface is aided by the confinement of polyethylene glycol acetate functionalized silver nanoparticles in thin slabs of a 1% agarose gel. The gel confined nanoparticles can be transferred between reaction and washing media simply by immersing the gel slab in the solution of interest. The agarose matrix retains nanoparticles but is swiftly penetrated by the antibodies of interest. The antibodies are covalently anchored to the nanoparticles using conventional crosslinking strategies, and the resulting antibody functionalized nanoparticles are recovered from the gel through electroelution. We demonstrate the efficacy of this nanoparticle functionalization approach by labeling specific receptors on cellular surfaces with functionalized silver nanoparticles that are stable under physiological conditions. PMID:20161660

  14. 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.

  15. Structural, magnetic and electrical characterization of Mg-Ni nano-crystalline ferrites prepared through egg-white precursor

    NASA Astrophysics Data System (ADS)

    Gabal, M. A.; Al Angari, Y. M.; Zaki, H. M.

    2014-08-01

    Soft Ni-Mg nano-crystalline ferrites with the general formula Ni1-xMgxFe2O4 (0≤x≤1) were synthesized through egg-white method. The precursor decomposition was followed by thermal analysis techniques. The obtained ferrites were characterized by X-ray diffraction, Fourier transform infrared and transmission electron microscopy measurements. X-ray diffraction showed the cubic spinel structure with crystallite size variation within the range 20-45 nm. The different structural data obtained were discussed in the view of ionic radii of the entire ions and their distribution within the lattice. The appropriate suggested cation distribution was then confirmed through Fourier transform infrared as well as electrical and magnetic properties measurements. Transmission electron microscopy exhibited a nano-crystal aggregation phenomenon. The observed size of the spherical particles agrees well with that obtained by X-ray diffraction. Hysteresis loop measurements revealed dilution in the obtained magnetic parameters by Mg-substitution due to the preferential occupancy of Mg2+ ions by the octahedral sites. Ac-electrical conductivity as a function of temperature and frequency exhibited a semi-conducting behavior with conductivity decreases by increasing Mg-content. The change in the slope of the curve indicates the changing in the conduction mechanism from electron hopping to polaron mechanism by increasing temperature. The obtained structural, electrical and magnetic properties were explained based on the cation distribution among tetrahedral and octahedral sites.

  16. 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.

  17. 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.

  18. 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

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

    PubMed Central

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

    2011-01-01

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

  20. 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. PMID:24287110

  1. 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.

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

    PubMed

    Khoee, S; Bagheri, Y; Hashemi, A

    2015-03-01

    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.

  3. 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.

  4. Synthesis and optical properties of sulfide nanoparticles prepared in dimethylsulfoxide.

    PubMed

    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.

  5. 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.

  6. Doping of inorganic materials in microreactors - preparation of Zn doped Fe3O4 nanoparticles.

    PubMed

    Simmons, M D; Jones, N; Evans, D J; Wiles, C; Watts, P; Salamon, S; Escobar Castillo, M; Wende, H; Lupascu, D C; Francesconi, M G

    2015-08-01

    Microreactor systems are now used more and more for the continuous production of metal nanoparticles and metal oxide nanoparticles owing to the controllability of the particle size, an important property in many applications. Here, for the first time, we used microreactors to prepare metal oxide nanoparticles with controlled and varying metal stoichiometry. We prepared and characterised Zn-substituted Fe3O4 nanoparticles with linear increase of Zn content (ZnxFe3-xO4 with 0 ≤ x ≤ 0.48), which causes linear increases in properties such as the saturation magnetization, relative to pure Fe3O4. The methodology is simple and low cost and has great potential to be adapted to the targeted doping of a vast array of other inorganic materials, allowing greater control on the chemical stoichiometry for nanoparticles prepared in microreactors. PMID:26099495

  7. Characterization of perovskite film prepared by pulsed laser deposition on ferritic stainless steel using microscopic and optical methods

    NASA Astrophysics Data System (ADS)

    Durda, E.; Jaglarz, J.; Kąc, S.; Przybylski, K.; El Kouari, Y.

    2016-06-01

    The perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF48) film was deposited on Crofer 22 APU ferritic stainless steel by pulsed laser deposition (PLD). Morphological studies of the sample were performed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Information about film thickness and surface topography of the film and the steel substrate were obtained using following optical methods: spectroscopic ellipsometry (SE), bidirectional reflection distribution function (BRDF) and total integrated reflectometry (TIS). In particular, the BRDF study, being complementary to atomic force microscopy, yielded information about surface topography. Using the previously mentioned methods, the following statistic surface parameters were determined: root-mean square (rms) roughness and autocorrelation length by determining the power spectral density (PSD) function of surface irregularities.

  8. 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.

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

    PubMed Central

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

    2012-01-01

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

  10. 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.

  11. 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.

  12. Investigation of structural and magnetic properties of co-precipitated Mn-Ni ferrite nanoparticles in the presence of α-Fe2O3 phase

    NASA Astrophysics Data System (ADS)

    Tirupanyam, B. V.; Srinivas, Ch.; Meena, S. S.; Yusuf, S. M.; Satish Kumar, A.; Sastry, D. L.; Seshubai, V.

    2015-10-01

    A systematic study on structural and magnetic properties of co-precipitated MnxNi1-xFe2O4 (x=0.5, 0.6, 0.7) ferrite nanoparticles annealed at 800 °C was carried out using XRD, FE-SEM, VSM and MÖSSBAUER techniques. Anti-ferromagnetic α-Fe2O3 phase was observed along with the magnetic spinel phase in the XRD patterns. It is observed that both lattice parameter and crystallite size of spinel phase increase with increase in concentration of Mn2+ along with the amount of α-Fe2O3 phase. The saturation magnetization (Ms) decreases while coercivity (Hc) increases with increase of Mn2+ ion concentration. Mössbauer spectra indicate that iron ions present in A and B sites are in the Fe3+ state and Fe2+ is absent. The results are interpreted in terms of observed anti-ferromagnetic α-Fe2O3 phase, core-shell interactions and cation redistribution.

  13. 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. PMID:26761626

  14. 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.

  15. 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.

  16. Preparation and pharmacokinetic evaluation of Tashinone IIA solid lipid nanoparticles.

    PubMed

    Liu, Jianping; Zhu, Jiabi; Du, Zhiyong; Qin, Bin

    2005-07-01

    Tashinone IIA loaded solid lipid nanoparticles (TA-SLN) coated with poloxamer 188 was prepared by emulsification/evaporation. The TA-SLN was characterized by transmission electron microscope and dynamic light scattering (DLS). The results showed that the TA-SLN had an average diameter of 98.7 nm with a zeta potential of - 31.6 mv and the drug loading of 4.6% and entrapment efficiency of 87.7%. In vitro release experiment showed that the release of Tashinone IIA from TA-SLN was in accordance with the Weibull equation. The best model fitting experimental data was a two-compartment open model with first-order. The area under curve of plasma concentration-time (AUC) and mean residence time (MRT) of TA-SLN were much higher than those of Tashinone IIA control solution (TA-SOL). The results of pharmacokinetic studies in rabbits indicated that the formulation of TA-SLN was successful in providing a delivery of slow release of Tashinone IIA. PMID:16109628

  17. 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.

  18. 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.

  19. 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.

  20. [Preparation and physicochemical study of the preservation of nanoparticles].

    PubMed

    Kamiya, Seitaro

    2015-01-01

    The importance of nanoparticle formulation is increasingly recognized in supporting pharmaceutical development. Thus, maintaining nanoparticles in a constant state is a major issue. A method involving lyophilization with the addition of saccharides can be used to maintain the steady state of nanoparticles. In this study, trisaccharides, tetrasaccharides, and pentasaccharides were added to nanoparticle suspensions, followed by rehydration of the samples, which had been either dried normally or freeze-dried. The particle size after rehydration was measured. In addition, each powder was measured using a powder X-ray diffractometer and thermal analysis device to investigate the correlation between the nanoparticles' aggregation and the crystal form of saccharides. The diameter of the nanoparticles was maintained when it was freeze-dried, while particle aggregation occurred when normally dried samples were used. In addition, crystalline saccharide was not observed in the freeze-dried group, but did appear in the normally dried group.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Preparation and In Vitro Evaluation of Hydrophilic Fenretinide Nanoparticles

    PubMed Central

    Ledet, Grace A.; Graves, Richard A.; Glotser, Elena Y.; Mandal, Tarun K.; Bostanian, Levon A.

    2015-01-01

    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 wasto 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 releasestudies 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 ± 35.5 ng/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

  6. 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.

  7. A highly efficient phase transfer method for preparing alkylamine-stabilized Ru, Pt, and Au nanoparticles.

    PubMed

    Yang, J; Lee, Jim Yang; Deivaraj, T C; Too, Heng-Phon

    2004-09-01

    A highly efficient phase-transfer method was developed to prepare alkylamine-stabilized nanoparticles of several noble metals. This method involved first mixing the metal hydrosols and an ethanol solution of dodecylamine and then extracting the dodecylamine-stabilized metal nanoparticles into toluene. The efficiency of this phase-transfer method was nearly 100%. Alkylamine-stabilized Ru, Pt, and Au nanoparticles 3.45, 4.33, and 7.89 nm in diameter, respectively, could be prepared this way. The self-assembly of dodecylamine-stabilized Pt and Au particles was also detected by transmission electron microscopy (TEM).

  8. 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.

  9. 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.

  10. 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.

  11. 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).

  12. 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.

  13. 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

  14. Preparation and in-vitro evaluation of indomethacin nanoparticles

    PubMed Central

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

    2010-01-01

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

  15. [Preparation of polyelectrolyte microcapsules containing ferrosoferric oxide nanoparticles].

    PubMed

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

    2011-01-01

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

  16. Preparation and properties of hydroxycamptothecin-loaded nanoparticles made of amphiphilic copolymer and normal polymer.

    PubMed

    Wang, Jinli; Wang, Rong; Li, Ling Bing

    2009-08-15

    Stabilized micelle structure nanoparticles were prepared using Pluronic F127 and poly(butylcyanoacrylate) (PBCA). To increase the drug loading of nanoparticles, D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) was additionally included into the nanoparticle composition. The poorly soluble anticancer drug 10-hydroxycamptothecin (HCPT) was used as a model drug and incorporated into nanoparticles. The results obtained from FT-IR and DSC confirmed that HCPT was molecularly dispersed in nanoparticles and no chemical reaction occurred. The size of the nanoparticles measured by DLS demonstrated that the size distribution was narrow and the average diameter was less than 200 nm. The morphology of the nanoparticles observed by TEM indicated that the nanoparticles exhibited a smooth surface and distinct spherical shape. In vitro release experiments indicated that the HCPT-loaded nanoparticles showed sustained release profiles. The results of a drug loading test revealed that adding TPGS could increase the drug loading. The drug loading of stabilized micelle structure nanoparticles with 70% of TPGS was about 0.0425+/-0.0011% w/w compared to 0.0254+/-0.0008% w/w found for the nanoparticles without TPGS. The results of CMC value tests showed that the CMC values of the stabilized nanoparticles were approximately 10-fold lower than those of the nonstabilized micelles (from 2.0x10(-5) to 2.5x10(-4) M). Cytotoxicity tests showed that the cytotoxicity of HCPT-loaded nanoparticles against cancer cells in vitro was remarkably higher than that of free drugs. 10-Hydroxycamptothecin-loaded nanoparticles may serve as a stable delivery system for poorly soluble HCPT.

  17. 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. PMID:16608315

  18. 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.

  19. 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.

  20. Dispersoid Distribution and Microstructure in Fe-Cr-Al Ferritic Oxide Dispersion-Strengthened Alloy Prepared by Friction Consolidation

    NASA Astrophysics Data System (ADS)

    Catalini, David; Kaoumi, Djamel; Reynolds, Anthony P.; Grant, Glenn J.

    2015-10-01

    INCOLOY® MA956 is a ferritic oxide dispersion-strengthened alloy manufactured by mechanical alloying followed by hot extrusion in vacuum-sealed cans or by degassing and hot isostatic pressing. This could be followed by a tailored heat treatment sequence in order to obtain a desired microstructure and to allow the oxide dispersion to precipitate. Three different oxides, responsible for the high-temperature mechanical strength, have been observed in this alloy: Y4Al2O9, YAlO3, and Y3Al5O12. Their sizes range from just a few to hundreds of nanometers. In this work, mechanically alloyed MA956 powder was consolidated via friction consolidation, a single-step and potentially cheaper processing alternative. Three fully dense compacts 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 by scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction. 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 grew in size.

  1. Using thermal energy produced by irradiation of Mn-Zn ferrite magnetic nanoparticles (MZF-NPs) for heat-inducible gene expression.

    PubMed

    Tang, Qiu-sha; Zhang, Dong-sheng; Cong, Xiao-ming; Wan, Mei-ling; Jin, Li-qiang

    2008-06-01

    One of the main advantages of gene therapy over traditional therapy is the potential to target the expression of therapeutic genes in desired cells or tissues. To achieve targeted gene expression, we developed a novel heat-inducible gene expression system in which thermal energy generated by Mn-Zn ferrite magnetic nanoparticles (MZF-NPs) under an alternating magnetic field (AMF) was used to activate gene expression. MZF-NPs, obtained by co-precipitation method, were firstly surface modified with cation poly(ethylenimine) (PEI). Then thermodynamic test of various doses of MZF-NPs was preformed in vivo and in vitro. PEI-MZF-NPs showed good DNA binding ability and high transfection efficiency. In AMF, they could rise to a steady temperature. To analyze the heat-induced gene expression under an AMF, we combined P1730OR vector transfection with hyperthermia produced by irradiation of MZF-NPs. By using LacZ gene as a reporter gene and Hsp70 as a promoter, it was demonstrated that expression of a heterogeneous gene could be elevated to 10 to 500-fold over background by moderate hyperthermia (added 12.24 or 25.81 mg MZF-NPs to growth medium) in tissue cultured cells. When injected with 2.6 or 4.6 mg MZF-NPs, the temperature of tumor-bearing nude mice could rise to 39.5 or 42.8 degrees C, respectively, and the beta-gal concentration could increase up to 3.8 or 8.1 mU/mg proteins accordingly 1 day after hyperthermia treatment. Our results therefore supported hyperthermia produced by irradiation of MZF-NPs under an AMF as a feasible approach for targeted heat-induced gene expression. This novel system made use of the relative low Curie point of MZF-NPs to control the in vivo hyperthermia temperature and therefore acquired safe and effective heat-inducible transgene expression.

  2. Tuning the magnetic properties of Co-ferrite nanoparticles through the 1,2-hexadecanediol concentration in the reaction mixture.

    PubMed

    Moya, Carlos; Morales, María del Puerto; Batlle, Xavier; Labarta, Amílcar

    2015-05-21

    This work reports on the effect of the 1,2-hexadecanediol content on the structural and magnetic properties of CoFe2O4 nanoparticles synthesized by thermal decomposition of metal-organic precursors in 1-octadecene. Although pseudo-spherical particles having an average size of about 8 nm and similar stoichiometry have been observed in all studied samples, a high level of variability in the crystal quality and, in turn, in the magnetic properties has been found as a function of the amount of 1,2-hexadecanediol added to the reaction mixture. The magnetic study reveals that samples progress from glassy magnetic behavior to bulk-like, ferrimagnetic order as the crystal quality improves. The analysis of the reaction mixtures by Fourier transform infrared spectroscopy at various stages of the reaction shows the key role of the 1,2-hexadecanediol in favoring the decomposition of the metal-organic precursor, formation of an intermediate Co(2+)Fe(3+)-oleate complex and, finally, the nucleation of nanoparticles at lower temperatures.

  3. 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.

  4. Fluoride adsorption by doped and un-doped magnetic ferrites CuCe(x)Fe(2-x)O4: Preparation, characterization, optimization and modeling for effectual remediation technologies.

    PubMed

    Rehman, Muhammad Abdur; Yusoff, Ismail; Alias, Yatimah

    2015-12-15

    A series of doped and un-doped magnetic adsorbents CuCexFe2-xO4 (x=0.0-0.5) for fluoride were prepared with the micro-emulsion method. Fluoride adsorption was optimized for solution pH, temperature, contact time, and initial concentration and was monitored via normal phase ion chromatography (IC). The effect of concomitant anions was also explored to perform and simulate competitive fluoride adsorption in real water samples. Optimal adsorption was discovered by a simple quadratic model based on central composite design (CCD) and the response surface method (RSM). The adsorption, electrochemical and magnetic properties were compared between doped and un-doped ferrites. Doped ferrites (x=0.1-0.5) were found to be superior to un-doped ferrites (x=0) regarding the active sites, functional groups and fluoride adsorption. The characterization, optimization and application results of the doped ferrites indicated enhanced fluoride adsorption and easy separation with a simple magnet.

  5. Preparation and characterization of realgar nanoparticles and their inhibitory effect on rat glioma cells

    PubMed Central

    An, Yan-li; Nie, Fang; Wang, Zi-yu; Zhang, Dong-sheng

    2011-01-01

    Aim Our objective was to prepare a new nano-sized realgar particle and characterize its anti-tumor effect on tumor cells. Methods Nanoparticles were prepared by coprecipitation and were detected by transmission electron microscopy, scanning electron microscopy, energy dispersive spectrometry (EDS), and dynamic light scattering. An anti-proliferative effect of realgar nanoparticles on rat glioma (C6) cells was determined by the MTT assay. Cell cycle and apoptosis rates were observed by flow cytometry. Apoptosis-related gene expression was detected by immunofluorescence staining. Results Realgar nanoparticles were successfully prepared. The particles were spherical, with an average diameter of approximately 80 nm, and contained arsenic and sulfur elements. Realgar nanoparticles inhibited C6 cell proliferation and induced apoptosis in a dose- and time-dependent manner. Treatment of C6 cells with realgar nanoparticles significantly increased the proportions of cells in S and G2/M phases, decreased the proportion of cells in G0/G1 phase, downregulated Bcl-2 expression, and substantially upregulated Bax expression. Conclusion Realgar nanoparticles significantly inhibited C6 glioma cell proliferation and promoted cell apoptosis by inducing the upregulation of Bax and downregulation of Bcl-2 expression. Realgar nanoparticles are a promising in vitro anti-cancer strategy and may be applicable for human cancer therapy studies. PMID:22238507

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

    PubMed Central

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

    2011-01-01

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

  7. 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. PMID:27651100

  8. The Preparation and Application of Magnetic Nanoparticles with Core-Shell Structure

    NASA Astrophysics Data System (ADS)

    Peng, Zhen; Yao, Ke-Fu; Liao, Zhenhua; Fu, Wenpeng

    It is well-known that TiO2 nanoparticles are highly efficient photocatalysts in decomposing organic substance in wastewater, especially when they are used in suspension state. However, if TiO2 nanoparticles cannot be withdrawn and reused, it is difficult to apply them in purification of wastewater due to the economic consideration. In present work, TiO2/SiO2/Fe3O4 core-shell magnetic nanoparticles, constituted by Fe3O4 core, SiO2 intermediary layer and the TiO2 out-shell, have been prepared and applied in photocatalytic degradation of a modulated methylene blue containing water. The results indicate that the as-prepared TiO2/SiO2/Fe3O4 nanoparticles possess high photocatalytic activity and the methylene blue in wastewater can be degraded quickly. Through comparing with the photocatalytic performance of the famous commercial P25 TiO2 nanoparticles in the same reaction condition, it has been found that as-prepared TiO2/SiO2/Fe3O4 nanoparticles exhibit similar photocatalytic activity to commercial P25 TiO2 nanoparticles in the photocatalytic degradation of methylene blue containing water. But the TiO2/SiO2/Fe3O4 nanoparticles used in suspension state can be simply recovered from the liquid by using a magnet or a magnetic field. So the cost of wastewater purification by photocatalytic degradation with TiO2/SiO2/Fe3O4 nanoparticles can be significantly reduced through reuse of the photocatalyst. It implies that TiO2/SiO2/Fe3O4 nanoparticles possess the potential for industrial application.

  9. Popping of graphite oxide: application in preparing metal nanoparticle catalysts.

    PubMed

    Gao, Yongjun; Chen, Xi; Zhang, Jiaguang; Asakura, Hiroyuki; Tanaka, Tsunehiro; Teramura, Kentaro; Ma, Ding; Yan, Ning

    2015-08-26

    A popcorn-like transformation of graphite oxide (GO) is reported and used to synthesize metal nanoparticle catalysts. The popping step is unique and essential, not only generating a high-surface-area support but also partially decomposing the metal precursors to form well-separated metal oxide nuclei, which would further evolve into highly dispersed and uniform-sized nanoparticles in the subsequent reduction. PMID:26179983

  10. Preparation and characterization of magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid

    NASA Astrophysics Data System (ADS)

    Qin, H.; Wang, C. M.; Dong, Q. Q.; Zhang, L.; Zhang, X.; Ma, Z. Y.; Han, Q. R.

    2015-05-01

    A novel and simple method has been proposed to prepare magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid (Fe3O4/CS/INH nanocomposites). Efforts have been made to develop isoniazid (INH) loaded chitosan (CS) nanoparticles by ionic gelation of chitosan with tripolyphosphate (TPP). The factors that influence the preparation of chitosan nanoparticles, including the TPP concentration, the chitosan/TPP weight ratio and the chitosan concentration on loading capacity and encapsulation efficiency of chitosan nanoparticles were studied. The magnetic Fe3O4 nanoparticles were prepared by co-precipitation method of Fe2+ and Fe3+. Then the magnetic Fe3O4/CS/INH nanocomposites were prepared by ionic gelation method. The magnetic Fe3O4 nanoparticles and magnetic Fe3O4/CS/INH nanocomposites were characterized by XRD, TEM, FTIR and SQUID magnetometry. The in vitro release of Fe3O4/CS/INH nanocomposites showed an initial burst release in the first 10 h, followed by a more gradual and sustained release for 48 h. It is suggested that the magnetic Fe3O4/CS/INH nanocomposites may be exploited as potential drug carriers for controlled-release applications in magnetic targeted drugs delivery system.

  11. 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.

  12. 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.

  13. Preparation and thermal behavior of aerosol-derived BaFe 12O 19 nanoparticles

    NASA Astrophysics Data System (ADS)

    Yu, Hsuan-Fu; Lin, Hsin-Yi

    2004-12-01

    Pure BaFe12O19 nanoparticles, having single magnetic domain sizes, were obtained at 700 °C using a process combining the citrate precursor method and spray technique. A neutralized aqueous solution, containing Ba2+ and Fe3+ chelated by citric acid, was nebulized to undergo thermal decomposition in a flowing air with a maximum temperature of 250 °C. The dried solid precursor so obtained was calcined at different temperatures and was then chemically and physically characterized. Crystalline barium hexaferrites were formed at temperatures as low as 650 °C, but calcination temperatures higher than 680 °C were required to produce pure barium ferrite powder. Based on the obtained experimental results, the reaction mechanism for the aerosol-derived precursor to form BaFe12O19 was proposed and discussed in this study.

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

    PubMed

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

    2009-01-15

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

  15. 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.

  16. 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

  17. 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. PMID:27427670

  18. 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.

  19. 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.

  20. A preliminary ferritic-martensitic stainless steel constitution diagram

    SciTech Connect

    Balmforth, M.C.; Lippold, J.C.

    1998-01-01

    This paper describes preliminary research to develop a constitution diagram that will more accurately predict the microstructure of ferritic and martensitic stainless steel weld deposits. A button melting technique was used to produce a wide range of compositions using mixtures of conventional ferritic and martensitic stainless steels, including types 403, 409, 410, 430, 439 and 444. These samples were prepared metallographically, and the vol-% ferrite and martensite was determined quantitatively. In addition, the hardness and ferrite number (FN) were measured. Using this data, a preliminary constitution diagram is proposed that provides a more accurate method for predicting the microstructures of arc welds in ferritic and martensitic stainless steels.

  1. Preparation of lisinopril-capped gold nanoparticles for molecular imaging of angiotensin-converting enzyme

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Baeta, Cesar; Aras, Omer; Daniel, Marie-Christine

    2009-05-01

    Overexpression of angiotensin-converting enzyme (ACE) has been associated with the pathophysiology of cardiac and pulmonary fibrosis. Moreover, the prescription of ACE inhibitors, such as lisinopril, has shown a favorable effect on patient outcome for patients with heart failure or systemic hypertension. Thus targeted imaging of the ACE would be of crucial importance for monitoring tissue ACE activity as well as the treatment efficacy in heart failure. In this respect, lisinopril-coated gold nanoparticles were prepared to provide a new type of probe for targeted molecular imaging of ACE by tuned K-edge computed tomography (CT) imaging. The preparation involved non-modified lisinopril, using its primary amine group as the anchoring function on the gold nanoparticles surface. The stable lisinopril-coated gold nanoparticles obtained were characterized by UV-vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM). Their zeta potential was also measured in order to assess the charge density on the modified gold nanoparticles (GNPs).

  2. 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.

  3. Development of alpha-tocopherol acetate nanoparticles: influence of preparative processes.

    PubMed

    Anais, J P; Razzouq, N; Carvalho, M; Fernandez, C; Astier, A; Paul, M; Astier, A; Fessi, H; Lorino, A M

    2009-02-01

    We studied different methods of preparing alpha-tocopherol acetate (ATA) nanoparticles, which are to be used in targeting the lungs as aerosols in order to prevent cigarette smoke toxicity. Poly-(lactide) nanoparticles were prepared using nanoprecipitation and solvent evaporation techniques, which produced, respectively, too small and too large nanoparticles to be aerosolized. The emulsification-diffusion method produced 2 months stable nanoparticles with a size between (500-700 nm). Increasing ATA concentration (1-7 mg/mL) induced a decrease in the association rate (97-93%) and in the adsorbed ATA rate (7-4.5%), which was associated with variations of Zeta potentials (-27.5 to -24.3 mV) and decrease in polymeric wall thickness and density.

  4. 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.

  5. 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.

  6. Nanoprecipitation versus two step desolvation technique for the preparation of gelatin nanoparticles

    NASA Astrophysics Data System (ADS)

    Khan, Saeed Ahmad; Schneider, Marc

    2013-02-01

    Various techniques have been used for preparation of gelatin nanoparticles, such as coacervation, emulsion/solvent evaporation, reverse phase preparation, inverse miniemulsion and two step desolvation. Both methods are based on different mechanisms of nanoparticle formation. The main goal of this study was to systematically compare the performance of nanoprecipitation and the most widely utilized two step desolvation methods with respect to effect of gelatin concentration on nanoparticle size and polydispersity index. Particles size was determined by dynamic light scattering, and the morphology by atomic force microscopy. It was observed that gelatin concentration 20 mg/ml yielded nanoparticles of around 60 nm size by two step desolvation, on the other hand nanoprecipitation produced 210 nm particles with the same gelatin concentration.

  7. 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 ...

  8. 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.

  9. 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

  10. Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: Structure, Preparation and Application.

    PubMed

    Naseri, Neda; Valizadeh, Hadi; Zakeri-Milani, Parvin

    2015-09-01

    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

  11. Phase Transition of Iron-Platinum Nanoparticles Prepared in Water-In-Oil Microemulsions

    NASA Astrophysics Data System (ADS)

    Hyie, Koay Mei; Yaacob, Iskandar Idris

    2009-06-01

    FePt nanoparticles were successfully prepared in water-in-oil microemulsions. Two different atmospheric conditions were used during annealing—argon and forming gas (95% argon+5% hydrogen). X-ray diffraction (XRD) result showed that fcc FePt nanoparticles annealed in forming gas atmosphere transformed into Pt3Fe phase. However, the as-synthesized fcc FePt could not be transformed to other phase in argon gas atmosphere. Variation of water/surfactant (w) ratio of 0.3, 0.5 and 0.65 were also investigated in order to produce fct FePt nanoparticles. After annealing at 700° C in forming gas atmosphere, FePt nanoparticles produced using w of 0.5 transformed into the ordered face centered tetragonal (fct) FePt structure while the nanoparticles formed using w of 0.3 and 0.65 turned into Pt3Fe phase.

  12. 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.

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

    PubMed

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

    2013-05-15

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

  14. Preparation and properties of silver nanoparticles loaded in activated carbon for biological and environmental applications.

    PubMed

    Tran, Quoc Tuan; Nguyen, Van Son; Hoang, Thi Kim Dung; Nguyen, Hoang Luong; Bui, Thu Thuy; Nguyen, Thi Van Anh; Nguyen, Dinh Hoa; Nguyen, Hoang Hai

    2011-09-15

    Silver nanoparticles colloid has been prepared by a modified sonoelectrodeposition technique in which a silver plate was used as the source of silver ions. This technique allows producing Ag nanoparticles with the size of 4-30 nm dispersed in a non-toxic solution. The Ag nanoparticles were loaded in a high surface activated carbon produced from coconut husk, a popular agricultural waste in Vietnam by thermal activation. The surface area of the best activated carbon is 890 m(2)/g. The presence of Ag nanoparticles does not change significantly properties of the activated carbon in terms of morphology and methylene blue adsorption ability. The Ag nanoparticle-loaded activated carbon shows a good antibacterial activity against Escherichia coli with very low minimal inhibitory concentration of 16 μg/ml and strong As(V) adsorption. The materials are potential for prevention and treatment of microbial infection and contamination for environmental applications.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Diverse Structural and Magnetic Properties of Differently Prepared MnAs Nanoparticles

    SciTech Connect

    Billinge, S.J.; Tian, P.; Zhang, Y.; Senevirathne, K.; Brock, S.L.; Dixit, A.; Lawes, G.

    2011-04-01

    Discrete nanoparticles of MnAs with distinct magnetostructural properties have been prepared by small modifications of solution-phase arrested precipitation reactions. Rietveld and X-ray atomic pair distribution function based approaches were used to explore the evolution of the structure of the samples with temperature, and these data were compared to the magnetic response measured with ac susceptibility. Relative to a bulk standard, one type of MnAs nanoparticles was found to demonstrate similar but smaller structural transitions and corresponding magnetic changes. However, both magnetic and structural transitions in the second type of nanoparticles are strongly suppressed.

  20. Single emulsion-solvent evaporation technique and modifications for the preparation of pharmaceutical polymeric nanoparticles.

    PubMed

    Nava-Arzaluz, María G; Piñón-Segundo, Elizabeth; Ganem-Rondero, Adriana; Lechuga-Ballesteros, David

    2012-12-01

    In recent years, there has been an increased interest in using nanoparticles for drug delivery and pharmaceutical development. Nanoparticles can offer significant advantages over the conventional drug delivery systems in terms of high drug loading, stability and specificity, controlled release capability, and the ability to deliver both hydrophilic and hydrophobic drug molecules through various routes of administration. This review article focuses on the use of the single emulsion solvent evaporation method, the first method proposed for the preparation of polymeric nanoparticles, and modifications that have been developed over the years to improve the results obtained with this technique.

  1. A smart platform for hyperthermia application in cancer treatment: cobalt-doped ferrite nanoparticles mineralized in human ferritin cages.

    PubMed

    Fantechi, Elvira; Innocenti, Claudia; Zanardelli, Matteo; Fittipaldi, Maria; Falvo, Elisabetta; Carbo, Miriam; Shullani, Valbona; Di Cesare Mannelli, Lorenzo; Ghelardini, Carla; Ferretti, Anna Maria; Ponti, Alessandro; Sangregorio, Claudio; Ceci, Pierpaolo

    2014-05-27

    Magnetic nanoparticles, MNPs, mineralized within a human ferritin protein cage, HFt, can represent an appealing platform to realize smart therapeutic agents for cancer treatment by drug delivery and magnetic fluid hyperthermia, MFH. However, the constraint imposed by the inner diameter of the protein shell (ca. 8 nm) prevents its use as heat mediator in MFH when the MNPs comprise pure iron oxide. In this contribution, we demonstrate how this limitation can be overcome through the controlled doping of the core with small amount of Co(II). Highly monodisperse doped iron oxide NPs with average size of 7 nm are mineralized inside a genetically modified variant of HFt, carrying several copies of α-melanocyte-stimulating hormone peptide, which has already been demonstrated to have excellent targeting properties toward melanoma cells. HFt is also conjugated to poly(ethylene glycol) molecules to increase its in vivo stability. The investigation of hyperthermic properties of HFt-NPs shows that a Co doping of 5% is enough to strongly enhance the magnetic anisotropy and thus the hyperthermic efficiency with respect to the undoped sample. In vitro tests performed on B16 melanoma cell line demonstrate a strong reduction of the cell viability after treatment with Co doped HFt-NPs and exposure to the alternating magnetic field. Clear indications of an advanced stage of apoptotic process is also observed from immunocytochemistry analysis. The obtained data suggest this system represents a promising candidate for the development of a protein-based theranostic nanoplatform. PMID:24689973

  2. Multiplexed TEM Specimen Preparation and Analysis of Plasmonic Nanoparticles

    PubMed Central

    Cheng, Anchi; Crum, John; Jain, Tilak; Duggan, Erika; Liu, Er; Nolan, John P.; Carragher, Bridget; Potter, Clinton S.

    2015-01-01

    We describe a system for rapidly screening hundreds of nanoparticle samples using transmission electron microscopy (TEM). The system uses a liquid handling robot to place up to 96 individual samples onto a single standard TEM grid at separate locations. The grid is then transferred into the TEM and automated software is used to acquire multi-scale images of each sample. The images are then analyzed to extract metrics on the size, shape, and morphology of the nanoparticles. The system has been used to characterize plasmonically-active nanomaterials. PMID:26223550

  3. 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.

  4. 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.

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

    PubMed

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

    2013-01-01

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

  7. Preparation and characterization of carboxyl functionalization of magnetite nanoparticles for oligonucleotide immobilization

    NASA Astrophysics Data System (ADS)

    Kim, Min-Jung; Jang, Dae-Hwan; Choa, Yong-Ho

    2010-05-01

    Fe3O4 nanoparticles prepared by the co-precipitation of Fe2+ and Fe3+ with NH4OH were simply modified by the carboxylic acid group of 3-thiopheneacetic acid (3TA) and meso-2,3-dimercaptosuccinic acid (DMSA). These functionalized Fe3O4 nanoparticles when coated with 3TA and DMSA have increased hydrophilic properties, thus causing them to be well dispersed in aqueous solutions. Then oligonucleotides (5'-AGC T-Amine-3') were immobilized on the carboxylic acid group-modified Fe3O4 nanoparticles. They were characterized by using FT-IR, XRD and TEM. The concentration of the oligonucleotide-modified Fe3O4 nanoparticles was investigated using a UV-vis spectrometer and compared to that of Fe3O4 nanoparticles without any surface modification. The Fe3O4 nanoparticles were spherical and the particle sizes were approximately 10 nm. The immobilizing efficiencies of the Fe3O4 nanoparticles modified with 3TA and DMSA were higher than those of the non-functionalized Fe3O4 nanoparticles.

  8. 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.

  9. 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 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.

  10. Preparation and Antibacterial Activity Evaluation of 18-β-glycyrrhetinic Acid Loaded PLGA Nanoparticles

    PubMed Central

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

    2015-01-01

    The aim of the present study was to formulate poly (lactide-co-glycolide) (PLGA) nanoparticles loaded with 18-β-glycyrrhetinic acid (GLA) with appropriate physicochemical properties and antimicrobial activity. GLA loaded PLGA nanoparticles were prepared with different drug to polymer ratios, acetone contents and sonication times and the antibacterial activity of the developed nanoparticles was examined against different gram-negative and gram-positive bacteria. The antibacterial effect was studied using serial dilution technique to determine the minimum inhibitory concentration of nanoparticles. Results demonstrated that physicochemical properties of nanoparticles were affected by the above mentioned parameters where nanoscale size particles ranging from 175 to 212 nm were achieved. The highest encapsulation efficiency (53.2 ± 2.4%) was obtained when the ratio of drug to polymer was 1:4. Zeta potential of the developed nanoparticles was fairly negative (-11±1.5). In-vitro release profile of nanoparticles showed two phases: an initial phase of burst release for 10 h followed by a slow release pattern up to the end. The antimicrobial results revealed that the nanoparticles were more effective than pure GLA against P. aeuroginosa, S. aureus and S. epidermidis. This improvement in antibacterial activity of GLA loaded nanoparticles when compared to pure GLA may be related to higher nanoparticles penetration into infected cells and a higher amount of GLA delivery in its site of action. Herein, it was shown that GLA loaded PLGA nanoparticles displayed appropriate physicochemical properties as well as an improved antimicrobial effect. PMID:25901144

  11. 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. PMID:26969594

  12. 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.

  13. Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment

    ERIC Educational Resources Information Center

    Sharma, R. K.; Gulati, Shikha; Mehta, Shilpa

    2012-01-01

    Assimilating green chemistry principles in nanotechnology is a developing area of nanoscience research nowadays. Thus, there is a growing demand to develop environmentally friendly and sustainable methods for the synthesis of nanoparticles that utilize nontoxic chemicals, environmentally benign solvents, and renewable materials to avoid their…

  14. Reversible formation of gold nanoparticle-surfactant composite assemblies for the preparation of concentrated colloidal solutions.

    PubMed

    Shalkevich, Natallia; Shalkevich, Andrey; Si-Ahmed, Lynda; Bürgi, Thomas

    2009-11-21

    We have developed a simple method for the preparation of nearly mono-dispersed stable gold colloids with a fairly high concentration using a two step procedure. First we synthesize citrate capped gold nanoparticles and then exchange the citrate ions with triethyleneglycolmono-11-mercaptoundecylether (EGMUDE). This leads to the immediate precipitation and formation of composite assemblies. The gold nanoparticles were successfully self-redispersed after a few days. The prepared gold colloid can be easily concentrated up to 20 times by separation of the flocculated part. UV-visible spectra, transmission electron microscopy (TEM), and dynamic light scattering (DLS) were used to characterize the products thus formed. PMID:19865774

  15. Reversible formation of gold nanoparticle-surfactant composite assemblies for the preparation of concentrated colloidal solutions.

    PubMed

    Shalkevich, Natallia; Shalkevich, Andrey; Si-Ahmed, Lynda; Bürgi, Thomas

    2009-11-21

    We have developed a simple method for the preparation of nearly mono-dispersed stable gold colloids with a fairly high concentration using a two step procedure. First we synthesize citrate capped gold nanoparticles and then exchange the citrate ions with triethyleneglycolmono-11-mercaptoundecylether (EGMUDE). This leads to the immediate precipitation and formation of composite assemblies. The gold nanoparticles were successfully self-redispersed after a few days. The prepared gold colloid can be easily concentrated up to 20 times by separation of the flocculated part. UV-visible spectra, transmission electron microscopy (TEM), and dynamic light scattering (DLS) were used to characterize the products thus formed.

  16. 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.

  17. Preparation and characterization of curcumin-piperine dual drug loaded nanoparticles

    PubMed Central

    Moorthi, C; Krishnan, Kiran; Manavalan, R; Kathiresan, K

    2012-01-01

    Objective To prepare curcumin-piperine (Cu-Pi) nanoparticles by various methods and to study the effect of various manufacturing parameters on Cu-Pi nanoparticles and to identify a suitable method for the preparation of Cu-Pi nanoparticles to overcome oral bioavailability and cancer cell targeting limitations in the treatment of cancer. Methods Cu-Pi nanoparticles were prepared by thin film hydration method, solid dispersion method, emulsion polymerization method and Fessi method. Optimization was carried out to study the effect of various manufacturing parameter on the Cu-Pi nanoparticles. Results Out of four methods, Fessi method produced a minimum average particle size of 85.43 nm with a polydispersity index of 0.183 and zeta potential of 29.7 mV. Change of organic solvent (acetone or ethanol) did not have any significant effect on Cu-Pi nanoparticles. However, increase in sonication time, stirring speed, viscosity, use of 1:10:10 ratio of drug/polymer/surfactant, and use of anionic surfactant or combination of anionic surfactant with cationic polymer or combination of non-ionic surfactant with cationic polymer had a significant effect on Cu-Pi nanoparticles. Conclusions Cu-Pi nanoparticles coated with PEG containing copolymer produced by Fessi method had a minimum average particle size, excellent polydispersity index and optimal zeta potential which fall within the acceptable limits of the study. This dual nanoparticulate drug delivery system appears to be promising to overcome oral bioavailability and cancer cell targeting limitations in the treatment of cancer. PMID:23569859

  18. Practical preparation procedures for docetaxel-loaded nanoparticles using polylactic acid-co-glycolic acid

    PubMed Central

    Keum, Chang-Gu; Noh, Young-Wook; Baek, Jong-Suep; Lim, Ji-Ho; Hwang, Chan-Ju; Na, Young-Guk; Shin, Sang-Chul; Cho, Cheong-Weon

    2011-01-01

    Background Nanoparticles fabricated from the biodegradable and biocompatible polymer, polylactic-co-glycolic acid (PLGA), are the most intensively investigated polymers for drug delivery systems. The objective of this study was to explore fully the development of a PLGA nanoparticle drug delivery system for alternative preparation of a commercial formulation. In our nanoparticle fabrication, our purpose was to compare various preparation parameters. Methods Docetaxel-loaded PLGA nanoparticles were prepared by a single emulsion technique and solvent evaporation. The nanoparticles were characterized by various techniques, including scanning electron microscopy for surface morphology, dynamic light scattering for size and zeta potential, x-ray photoelectron spectroscopy for surface chemistry, and high-performance liquid chromatography for in vitro drug release kinetics. To obtain a smaller particle, 0.2% polyvinyl alcohol, 0.03% D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), 2% Poloxamer 188, a five-minute sonication time, 130 W sonication power, evaporation with magnetic stirring, and centrifugation at 8000 rpm were selected. To increase encapsulation efficiency in the nanoparticles, certain factors were varied, ie, 2–5 minutes of sonication time, 70–130 W sonication power, and 5–25 mg drug loading. Results A five-minute sonication time, 130 W sonication power, and a 10 mg drug loading amount were selected. Under these conditions, the nanoparticles reached over 90% encapsulation efficiency. Release kinetics showed that 20.83%, 40.07%, and 51.5% of the docetaxel was released in 28 days from nanoparticles containing Poloxamer 188, TPGS, or polyvinyl alcohol, respectively. TPGS and Poloxamer 188 had slower release kinetics than polyvinyl alcohol. It was predicted that there was residual drug remaining on the surface from x-ray photoelectron spectroscopy. Conclusion Our research shows that the choice of surfactant is important for controlled release of

  19. 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

  20. 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. PMID:27209386

  1. 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

  2. Porous silicon nanoparticles for nanomedicine: preparation and biomedical applications.

    PubMed

    Santos, Hélder A; Mäkilä, Ermei; Airaksinen, Anu J; Bimbo, Luis M; Hirvonen, Jouni

    2014-04-01

    The research on porous silicon (PSi) materials for biomedical applications has expanded greatly since the early studies of Leigh Canham more than 25 years ago. Currently, PSi nanoparticles are receiving growing attention from the scientific biomedical community. These nanostructured materials have emerged as promising multifunctional and versatile platforms for nanomedicine in drug delivery, diagnostics and therapy. The outstanding properties of PSi, including excellent in vivo biocompatibility and biodegradability, have led to many applications of PSi for delivery of therapeutic agents. In this review, we highlight current advances and recent efforts on PSi nanoparticles regarding the production properties, efficient drug delivery, multidrug delivery, permeation across biological barriers, biosafety and in vivo tracking for biomedical applications. The constant boost on successful preclinical in vivo data reported so far makes this the 'golden age' for PSi, which is expected to finally be translated into the clinic in the near future.

  3. Magnetic lipid nanoparticles loading doxorubicin for intracellular delivery: Preparation and characteristics

    NASA Astrophysics Data System (ADS)

    Ying, Xiao-Ying; Du, Yong-Zhong; Hong, Ling-Hong; Yuan, Hong; Hu, Fu-Qiang

    2011-04-01

    Tumor intracellular delivery is an effective route for targeting chemotherapy to enhance the curative effect and minimize the side effect of a drug. In this study, the magnetic lipid nanoparticles with an uptake ability by tumor cells were prepared dispersing ferroso-ferric oxide nanoparticles in aqueous phase using oleic acid (OA) as a dispersant, and following the solvent dispersion of lipid organic solution. The obtained nanoparticles with 200 nm volume average diameter and -30 mV surface zeta potential could be completely removed by external magnetic field from aqueous solution. Using doxorubicin (DOX) as a model drug, the drug-loaded magnetic lipid nanoparticles were investigated in detail, such as the effects of OA, drug and lipid content on volume average diameter, zeta potential, drug encapsulation efficiency, drug loading, and in vitro drug release. The drug loading capacity and encapsulation efficiency were enhanced with increasing drug or lipid content, reduced with increasing OA content. The in vitro drug release could be controlled by changing drug or lipid content. Cellular uptake by MCF-7 cells experiment presented the excellent internalization ability of the prepared magnetic lipid nanoparticles. These results evidenced that the present magnetic lipid nanoparticles have potential for targeting therapy of antitumor drugs.

  4. Boronic Acid functionalized core-shell polymer nanoparticles prepared by distillation precipitation polymerization for glycopeptide enrichment.

    PubMed

    Qu, Yanyan; Liu, Jianxi; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2012-07-16

    The boronic acid-functionalized core-shell polymer nanoparticles, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@4-vinylphenylboronic acid (poly(MBA-co-MAA)@VPBA), were successfully synthesized for enriching glycosylated peptides. Such nanoparticles were composed of a hydrophilic polymer core prepared by distillation precipitation polymerization (DPP) and a boronic acid-functionalized shell designed for capturing glycopeptides. Owing to the relatively large amount of residual vinyl groups introduced by DPP on the core surface, the VPBA monomer was coated with high efficiency, working as the shell. Moreover, the overall polymerization route, especially the use of DPP, made the synthesis of nanoparticles facile and time-saving. With the poly(MBA-co-MAA)@VPBA nanoparticles, 18 glycopeptides from horseradish peroxidase (HRP) digest were captured and identified by MALDI-TOF mass spectrometric analysis, relative to eight glycopeptides enriched by using commercially available meta-aminophenylboronic acid agarose under the same conditions. When the concentration of the HRP digest was decreased to as low as 5 nmol, glycopeptides could still be selectively isolated by the prepared nanoparticles. Our results demonstrated that the synthetic poly(MBA-co-MAA)@VPBA nanoparticles might be a promising selective enrichment material for glycoproteome analysis. PMID:22707097

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

    PubMed

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

    2014-11-01

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

  6. Biophysical inhibition of synthetic vs. naturally-derived pulmonary surfactant preparations by polymeric nanoparticles.

    PubMed

    Beck-Broichsitter, Moritz; Ruppert, Clemens; Schmehl, Thomas; Günther, Andreas; Seeger, Werner

    2014-01-01

    Reasonable suspicion has accumulated that inhaled nano-scale particulate matter influences the biophysical function of the pulmonary surfactant system. Hence, it is evident to provide novel insights into the extent and mechanisms of nanoparticle-surfactant interactions in order to facilitate the fabrication of safe nanomedicines suitable for pulmonary applications. Negatively- and positively-charged poly(styrene) nanoparticles (diameters of ~100nm) served as model carriers. Nanoparticles were incubated with several synthetic and naturally-derived pulmonary surfactants to characterize the sensitivity of each preparation to biophysical inactivation. Changes in surface properties (i.e. adsorption and dynamic surface tension behavior) were monitored in a pulsating bubble surfactometer. Both nanoparticle formulations revealed a dose-dependent influence on the biophysical behavior of all investigated pulmonary surfactants. However, the surfactant sensitivity towards inhibition depended on both the carrier type, where negatively-charged nanoparticles showed increased inactivation potency compared to their positively-charged counterparts, and surfactant composition. Among the surfactants tested, synthetic mixtures (i.e. phospholipids, phospholipids supplemented with surfactant protein B, and Venticute®) were more susceptible to surface-activity inhibition as the more complex naturally-derived preparations (i.e. Alveofact® and large surfactant aggregates isolated from rabbit bronchoalveolar lavage fluid). Overall, nanoparticle characteristics and surfactant constitution both influence the extent of biophysical inhibition of pulmonary surfactants.

  7. Curcumin-Loaded Lipid Cubic Liquid Crystalline Nanoparticles: Preparation, Optimization, Physicochemical Properties and Oral Absorption.

    PubMed

    He, Xiuli; Li, Qinghua; Liu, Xiuju; Wu, Guangsheng; Zhai, Guangxi

    2015-08-01

    In order to improve the oral absorption of curcumin, curcumin-loaded lipid cubic liquid crystalline nanoparticles were prepared and evaluated in vitro and in vivo. The hot and high-pressure homogenization method was used to prepare the nanoparticles. The formulation and process were optimized by uniform design with drug loading and entrapment efficiency as index, and physicochemical properties were also investigated. Spherical nanoparticles were observed under transmission electron microscope (TEM), with average particle size of 176.1 nm, zeta potential of -25.19 mV, average drug loading of (1.5 ± 0.2)% and entrapment efficiency of (95 ± 1.8)%. The in vitro release of curcumin from the nanoparticle formulation showed a sustained property, while the pharmacokinetics results after oral administration of curcumin loaded lipid cubic liquid crystalline nanoparticles in rat showed that the oral absorption of curcumin fitted one-compartment model and relative bioavailability was 395.56% when compared to crude curcumin. It can be concluded from these results that the lipid cubic liquid crystalline nanoparticles, as carriers, can markedly improve the oral absorption of curcumin.

  8. Preparation and Characterization of Cationic PLA-PEG Nanoparticles for Delivery of Plasmid DNA

    NASA Astrophysics Data System (ADS)

    Zou, Weiwei; Liu, Chunxi; Chen, Zhijin; Zhang, Na

    2009-09-01

    The purpose of the present work was to formulate and evaluate cationic poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles as novel non-viral gene delivery nano-device. Cationic PLA-PEG nanoparticles were prepared by nanoprecipitation method. The gene loaded nanoparticles were obtained by incubating the report gene pEGFP with cationic PLA-PEG nanoparticles. The physicochemical properties (e.g., morphology, particle size, surface charge, DNA binding efficiency) and biological properties (e.g., integrity of the released DNA, protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in Hela cells) of the gene loaded PLA-PEG nanoparticles were evaluated, respectively. The obtained cationic PLA-PEG nanoparticles and gene loaded nanoparticles were both spherical in shape with average particle size of 89.7 and 128.9 nm, polydispersity index of 0.185 and 0.161, zeta potentials of +28.9 and +16.8 mV, respectively. The obtained cationic PLA-PEG nanoparticles with high binding efficiency (>95%) could protect the loaded DNA from the degradation by nuclease and plasma. The nanoparticles displayed sustained-release properties in vitro and the released DNA maintained its structural and functional integrity. It also showed lower cytotoxicity than Lipofectamine 2000 and could successfully transfect gene into Hela cells even in presence of serum. It could be concluded that the established gene loaded cationic PLA-PEG nanoparticles with excellent properties were promising non-viral nano-device, which had potential to make cancer gene therapy achievable.

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

    PubMed

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

    2014-11-01

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

  10. Preparation of Fe3O4 Nanoparticles and Removal of Methylene Blue through Adsorption

    NASA Astrophysics Data System (ADS)

    Trujillo Hernandez, J. S.; Aragón Muriel, A.; Tabares, J. A.; Pérez Alcázar, G. A.; Bolaños, A.

    2015-07-01

    In this work, we studied the catalytic activity, structural properties, and behavior of a Fe3O4 magnetic system. The Fe3O4 nanoparticles were prepared by the thermal decomposition method. X-ray diffraction confirmed the presence of a structural Fe3O4 phase, where acicular shape of the grains is shown. Transmission Mossbauer spectroscopy showed a wide distribution of particle sizes at room temperature, some of these present superparamagnetic behavior and are responsible of paramagnetic sites. The hysteresis loops obtained by the use of a vibrating sample magnetometer showed that these nanoparticles exhibit superparamagnetic behavior. However, the cycles present a significant contribution from a ferrimagnetic component at 2 K, which agrees with Mossbauer results. Through scanning electron microscopy, a tendency to the agglomeration of nanoparticles was observed. Nanoparticle activity in the degradation of methylene blue (MB) was studied through fluorescence spectroscopy, finding dye adsorption properties.

  11. Preparation of silver nanoparticles in virgin coconut oil using laser ablation.

    PubMed

    Zamiri, Reza; Azmi, B Z; Sadrolhosseini, Amir Reza; Ahangar, Hossein Abbastabar; Zaidan, A W; Mahdi, M A

    2011-01-07

    Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10(-8), 1.6 × 10(-8), 2.4 × 10(-8), respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method.

  12. Preparation and characterization of poly (ethylene glycol)-coated Stoeber silica nanoparticles for biomedical applications

    NASA Astrophysics Data System (ADS)

    Kopelman, Raoul; Xu, Hao; Yan, Fei; Monson, Eric E.; Tang, Wei; Schneider, Randy; Philbert, Martin A.

    2002-06-01

    Monodisperse, spherical, polyethylene glycol (PEG)-coated silica nanoparticles have been prepared in the size range of 50-350 nm, and their size distribution were characterized by SEM and multi-angle static light scattering experiments. The chemical binding of PEG to the silica nanoparticles was confirmed by IR spectroscopy. The biocompatibility of these PEGylated nanoparticles was also studied by non-specific protein binding tests and in-vivo toxicology studies in live animals. These silica nanoparticles, as a matrix for encapsulation of certain reagents, have been used for the fabrication of intracellular sensors and have potential for applications to in vivo diagnosis, analysis and measurements, due to their small physical size and their biocompatibility, both stemming from the specialized PEG coating.

  13. Preparation of silver nanoparticles in virgin coconut oil using laser ablation

    PubMed Central

    Zamiri, Reza; Azmi, B Z; Sadrolhosseini, Amir Reza; Ahangar, Hossein Abbastabar; Zaidan, A W; Mahdi, M A

    2011-01-01

    Laser ablation of a silver plate immersed in virgin coconut oil was carried out for fabrication of silver nanoparticles. A Nd:YAG laser at wavelengths of 1064 nm was used for ablation of the plate at different times. The virgin coconut oil allowed formation of nanoparticles with well-dispersed, uniform particle diameters that were stable for a reasonable length of time. The particle sizes and volume fraction of nanoparticles inside the solutions obtained at 15, 30, 45 min ablation times were 4.84, 5.18, 6.33 nm and 1.0 × 10−8, 1.6 × 10−8, 2.4 × 10−8, respectively. The presented method for preparation of silver nanoparticles in virgin coconut oil is environmentally friendly and may be considered a green method. PMID:21289983

  14. Starch based biodegradable graft copolymer for the preparation of silver nanoparticles.

    PubMed

    Das, Subhadip; Sasmal, Dinabandhu; Pal, Sagar; Kolya, Haradhan; Pandey, Akhil; Tripathy, Tridib

    2015-11-01

    The synthesis and characterization of a novel biodegradable graft copolymer based on partially hydrolyzed polymethylacrylate (PMA) grafted amylopectin (AP) was reported which was developed for the synthesis of silver nanoparticles from silver nitrate solution by facile green technique. The prepared graft copolymer was biodegradable which was shown by fungal growth. Characterization of silver nanoparticles was carried out by UV-VIS spectroscopy (417nm), HR-TEM, SAED and FESEM analysis. The TEM findings revealed that the silver nanoparticles are crystalline and globular shaped with average particle size ranging from 11 to 15nm. The synthesized silver nanoparticles exhibit excellent antibacterial sensitivity towards both Gram negative and Gram positive bacteria namely Vibrio parahaemolyticus (ATCC-17802) and Bacillus cereus (ATCC-14579) respectively and were also shown a good catalytic activity towards 4-nitrophenol reduction.

  15. Preparation of AgX (X = Cl, I) nanoparticles using ionic liquids

    NASA Astrophysics Data System (ADS)

    Rodil, Eva; Aldous, Leigh; Hardacre, Christopher; Lagunas, M. Cristina

    2008-03-01

    Nanoparticles of silver halides have been prepared by mixing silver halide powder with a single liquid phase consisting of an ionic liquid, isooctane, n-decanol and water. Much higher nanoparticle concentrations may be formed with ionic liquids using this new simple method than are found with conventionally applied surfactants. This method also emphasizes the applicability of ionic liquids as versatile components in microemulsions and as solvents for the synthesis of nanomaterials. The effect on the nanoparticles of changing the composition of the liquid mixtures and the nature of the ionic liquid is analysed. High nanoparticle concentrations were only found with chloride based ionic liquids, indicating the importance of the ionic liquid anion in the mechanism of the reaction.

  16. Preparation of tourmaline nano-particles through a hydrothermal process and its infrared emission properties.

    PubMed

    Xue, Gang; Han, Chao; Liang, Jinsheng; Wang, Saifei; Zhao, Chaoyue

    2014-05-01

    Tourmaline nano-particles were successfully prepared via a hydrothermal process using HCl as an additive. The reaction temperature (T) and the concentration of HCI (C(HCl)) had effects on the size and morphology of the tourmaline nano-particles. The optimum reaction condition was that: T = 180 degrees C and C(HCl) = 0.1 mol/l. The obtained nano-particles were spherical with the diameter of 48 nm. The far-infrared emissivity of the product was 0.923. The formation mechnism of the tourmaline nano-particles might come from the corrosion of grain boundary between the tourmaline crystals in acidic hydrothermal conditions and then the asymmetric contraction of the crystals. PMID:24734669

  17. Microwave Absorption Properties of Iron Nanoparticles Prepared by Ball-Milling

    NASA Astrophysics Data System (ADS)

    Chu, Xuan T. A.; Ta, Bach N.; Ngo, Le T. H.; Do, Manh H.; Nguyen, Phuc X.; Nam, Dao N. H.

    2016-05-01

    A nanopowder of iron was prepared using a high-energy ball milling method, which is capable of producing nanoparticles at a reasonably larger scale compared to conventional chemical methods. Analyses using x-ray diffraction and magnetic measurements indicate that the iron nanoparticles are a single phase of a body-centered cubic structure and have quite stable magnetic characteristics in the air. The iron nanoparticles were then mixed with paraffin and pressed into flat square plates for free-space microwave transmission and reflection measurements in the 4-8 GHz range. Without an Al backing plate, the Fe nanoparticles seem to only weakly absorb microwave radiation. The reflected signal S 11 drops to zero and a very large negative value of reflection loss ( RL) are observed for Al-backed samples, suggesting the existence of a phase matching resonance near frequency f ˜ 6 GHz.

  18. pH-responsive lyotropic liquid crystals for the preparation of pure cubic zirconia nanoparticles

    NASA Astrophysics Data System (ADS)

    He, Wei Yan; Liu, Jin Rong; He, Zhang; Cao, Zhen Zhu; Li, Cai Hong; Gao, Yan Fang

    2016-07-01

    We present a lyotropic liquid crystal system consisting of SDS/Triton X-100/water at 25 °C. This system is respond to pH variations with a phase switch. When pH is altered from alkaline (pH 13) to acidic (pH 2) conditions, phase change occurs from a bicontinuous hexagonal phase to a partially hexagonal phase until it disappears. The hexagonal phase under alkaline conditions is stable. Thus, this system is an ideal candidate for the preparation of pure cubic ZrO2 nanoparticles. XRD results confirm that the as-synthesized powder is composed of pure cubic ZrO2. These nanoparticles also exhibit a thermal stability of up to 800 °C. The size and morphological characteristics of the nanoparticles are greatly affected by ZrOCl2 concentration. The mechanism of zirconia nanoparticle synthesis in a lyotropic hexagonal phase was proposed.

  19. Preparation, characterization, and cytotoxic effects of liposomal nanoparticles containing cisplatin: an in vitro study.

    PubMed

    Poy, Donya; Akbarzadeh, Azim; Ebrahimi Shahmabadi, Hasan; Ebrahimifar, Meysam; Farhangi, Ali; Farahnak Zarabi, Maryam; Akbari, Azam; Saffari, Zahra; Siami, Fatemeh

    2016-10-01

    Cisplatin is a chemotherapeutic agent used for treating various malignancies. The study aimed to prepare pegylated liposomal cisplatin and evaluate its efficacy against human breast cancer cell line MCF-7. Drug-loaded nanoparticles were synthesized by reverse phase evaporation technique. The study is highlighted by extensive characterization of nanoparticles in terms of nanoparticle morphology, type of drug entrapment, cisplatin retention capability, and cytotoxicity effects. The size, size distribution, and zeta potential of nanodrug were estimated 142 nm, 0.33, and -22 mV, respectively. Drug-loading efficiency was equal to 48% that occurred physically. Furthermore, high retention capability (39% of drug was released after 72 h) with significantly enhanced cytotoxicity of nanodrug (1.75 times more than the standard drug) confirmed the potency of liposomal nanoparticles as proper cisplatin carrier. PMID:27178305

  20. Preparation of tourmaline nano-particles through a hydrothermal process and its infrared emission properties.

    PubMed

    Xue, Gang; Han, Chao; Liang, Jinsheng; Wang, Saifei; Zhao, Chaoyue

    2014-05-01

    Tourmaline nano-particles were successfully prepared via a hydrothermal process using HCl as an additive. The reaction temperature (T) and the concentration of HCI (C(HCl)) had effects on the size and morphology of the tourmaline nano-particles. The optimum reaction condition was that: T = 180 degrees C and C(HCl) = 0.1 mol/l. The obtained nano-particles were spherical with the diameter of 48 nm. The far-infrared emissivity of the product was 0.923. The formation mechnism of the tourmaline nano-particles might come from the corrosion of grain boundary between the tourmaline crystals in acidic hydrothermal conditions and then the asymmetric contraction of the crystals.

  1. Nanoparticle infiltration to prepare solvent-free controlled drug delivery systems.

    PubMed

    Rodríguez-Cruz, Isabel M; Domínguez-Delgado, Clara L; Escobar-Chávez, Jose J; Leyva-Gómez, Gerardo; Ganem-Quintanar, Adriana; Quintanar-Guerrero, David

    2009-04-17

    The purpose of this work was to propose a drug delivery system based on a biodegradable porous membrane, whose surface is covered by a nanoparticle film, thus achieving a controlled drug release rate. Furthermore, due to the fact that the assembly of the system is performed in aqueous medium, contact with organic solvents is avoided. The method is performed in two steps: (i) preparation of biodegradable porous membranes (by a solvent casting and particulate leaching technique) and biodegradable nanoparticles (by the emulsification-diffusion method), extensively eliminating the solvent in both of them; (ii) infiltration into membranes of an aqueous solution of a model drug (carbamazepine) and a nanoparticle dispersion. In both cases, poly(DL-lactic-co-glycolic acid) (PLGA 50:50) was used as a biodegradable polymer. Carbamazepine adsorbed onto biodegradable porous membranes shows an immediate release behavior (95% released in <15 min). Infiltration of different amounts of nanoparticles (50, 100, 400 and 600 mg of nanoparticles/0.625 g of membrane) into biodegradable porous membranes shows a Fickian diffusion according to Peppas model, and fits Higuchi's model. This behavior was attributed to the diffusional barrier constituted by the nanoparticle film. As expected, the carbamazepine release rate was dependent on the amount of infiltrated/adsorbed nanoparticles into biodegradable porous membrane. DSC studies show molecular dispersion of the drug throughout the membrane.

  2. Preparation and antibacterial activity of Fe3O4@Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Gong, Ping; Li, Huimin; He, Xiaoxiao; Wang, Kemin; Hu, Jianbing; Tan, Weihong; Zhang, Shouchun; Yang, Xiaohai

    2007-07-01

    Bifunctional Fe3O4@Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are present in the same particle. The superparamagnetism of Fe3O4@Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe3O4@Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe3O4@Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe3O4@Ag nanoparticles can still have antibacterial capability and can be reused.

  3. Preparation and characterization of surface-coated ZnS nanoparticles

    SciTech Connect

    Chen, S.; Liu, W.

    1999-11-09

    ZnS nanoparticles coated with di-n-hexadecyldithiophosphate (DDP) were chemically synthesized. The structure of the prepared ZnS nanoparticles was investigated by means of transmission electron microscopy, electron diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The thermal stability of DDP coated on nanoparticles was compared with that of pyridinium di-n-hexadecyldithiophosphate (PyDDP) using a thermogravimetric analyzer. The tribiological properties of ZnS nanoparticles as an additive in tetradecane were investigated by a SRV tester in a ball-on-disk configuration. DDP-coated ZnS nanoparticles, with an average diameter of about 4 nm, are able to prevent water adsorption, and oxidation and are capable of being dispersed stably in organic solvents or mineral oil. Thermal stability of DDP coating on ZnS nanoparticles was superior to that of PyDDP. Wear tests show that DDP-coated ZnS nanoparticles as additive in tetradecane are capable of reducing friction and wear of steel.

  4. Gold nanoparticles prepared by electro-exploding wire technique in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Kumar, Lalit; Kapoor, Akanksha; Meghwal, Mayank; Annapoorni, S.

    2016-05-01

    This article presents an effective approach for the synthesis of Au nanoparticles via an environmentally benevolent electro-exploding wire (EEW) technique. In this process, Au nanoparticles evolve through the plasma generated from the parent Au metal. Compared to other typical chemical methods, electro-exploding wire technique is a simple and economical technique which normally operates in water or organic liquids under ambient conditions. Efficient size control was achieved using different aqueous medium like (1mM) NaCl, deionized water and aqueous solution of sodium hydroxide (NaOH, pH 9.5) using identical electro-exploding conditions. The gold nanoparticles exhibited the UV-vis absorption spectrum with a maximum absorption band at 530 nm, similar to that of gold nanoparticles chemically prepared in a solution. The mechanism of size variation of Au nanoparticles is also proposed. The results obtained help to develop methodologies for the control of EEW based nanoparticle growth and the functionalization of nanoparticle surfaces by specific interactions.

  5. The impact of oxygen on the morphology of gas-phase prepared Au nanoparticles

    SciTech Connect

    Pohl, D.; Surrey, A.; Schultz, L.; Rellinghaus, B.

    2012-12-24

    We present an easy procedure for the synthesis of single crystalline gold nanoparticles with a mean diameter of 4 nm using a DC-sputtering in an argon-oxygen gas mixture. Morphology population statistics have been determined to quantify the influence of oxygen. It is found that the particles undergo a structural transition from predominantly icosahedral to single crystalline particles with increasing amount of oxygen. Aberration-corrected high-resolution transmission electron microscopy investigation proves that likewise prepared single crystalline nanoparticles are defect and oxygen free. In contrast, the icosahedral particles prepared with pure argon show the presence of edge dislocations pointing to an energetic disfavoring already at these relatively small particle sizes. This morphology control of clean and uncovered Au nanoparticles provides a high application potential, e.g., for studying the influence of the particle morphology on plasmonic and catalytic properties.

  6. Pure single crystallographic form of TiO2 nanoparticles: Preparation and characterization

    NASA Astrophysics Data System (ADS)

    Bhatt, Piyush J.; Tomar, Laxmi J.; Desai, Rahul K.; Chakrabarty, Bishwajit S.

    2015-06-01

    TiO2 nanoparticles in three pure crystallographic forms (anatase, rutile and Brookite) have been prepared by hydrothermal and precipitation method. XRD analysis showed that the prepared nanoparticles using hydrothermal method for 2h and 24h were pure Brookite and pure anatase respectively. Pure rutile phase of TiO2 nanoparticles has been obtained by precipitation method. The average crystallite size for anatase, rutile and Brookite was found to be 14.71 nm, 12.88 nm and 5.27 nm respectively. This nano size of crystals has produced lattice strain in material, and this strain varies with size and structure. The UV-Visible absorption analysis showed that the energy gaps for anatase, rutile and Brookite are 3.32 eV, 2.45 eV and 2.60 eV respectively. Refractive index of all the samples has been changed compared to the bulk TiO2.

  7. Preparation of iron oxide nanoparticles from FeCl3 solid powder using microemulsions

    NASA Astrophysics Data System (ADS)

    Nassar, Nashaat; Husein, Maen

    2006-05-01

    Nanoparticles of iron oxide were prepared by subjecting iron chloride powder to (w/o) microemulsions consisting of sodium bis(2-ethylhexyl) sulfosuccinate (AOT), isooctane and water. FeCl3 was first dissolved in the water pools of the microemulsion, and then reacted with NaOH added as an aqueous solution to form iron oxide. The amount of NaOH solution was limited so that single microemulsion phase is obtained. This technique serves as an in-situ nanoparticle preparation technique aimed at minimizing particle aggregation associated with particle transportation to required sites. In this study, the effects of AOT concentration and water to AOT mole ratio on the nanoparticle size were investigated. UV/Vis spectrophotometry and transmission electron microscopy (TEM) were used to measure the particle size distribution.

  8. Semiconductor nanoparticle-based hydrogels prepared via self-initiated polymerization under sunlight, even visible light

    PubMed Central

    Zhang, Da; Yang, Jinhu; Bao, Song; Wu, Qingsheng; Wang, Qigang

    2013-01-01

    Since ancient times, people have used photosynthesized wood, bamboo, and cotton as building and clothing materials. The advantages of photo polymerization include the mild and easy process. However, the direct use of available sunlight for the preparation of materials is still a challenge due to its rather dilute intensity. Here, we show that semiconductor nanoparticles can be used for initiating monomer polymerization under sunlight and for cross-linking to form nanocomposite hydrogels with the aid of clay nanosheets. Hydrogels are an emerging multifunctional platform because they can be easily prepared using solar energy, retain semiconductor nanoparticle properties after immobilization, exhibit excellent mechanical strength (maximum compressive strength of 4.153 MPa and tensile strength 1.535 MPa) and high elasticity (maximum elongation of 2784%), and enable recyclable photodegradation of pollutants. This work suggests that functional nanoparticles can be immobilized in hydrogels for their collective application after combining their mechanical and physiochemical properties. PMID:23466566

  9. A Novel Method for the Preparation of Retinoic Acid-Loaded Nanoparticles

    PubMed Central

    Errico, Cesare; Gazzarri, Matteo; Chiellini, Federica

    2009-01-01

    The goal of present work was to investigate the use of bioerodible polymeric nanoparticles as carriers of retinoic acid (RA), which is known to induce differentiation of several cell lines into neurons. A novel method, named “Colloidal-Coating”, has been developed for the preparation of nanoparticles based on a copolymer of maleic anhydride and butyl vinyl ether (VAM41) loaded with RA. Nanoparticles with an average diameter size of 70 nm and good morphology were prepared. The activity of the encapsulated RA was evaluated on SK-N-SH human neuroblastoma cells, which are known to undergo inhibition of proliferation and neuronal differentiation upon treatment with RA. The activity of RA was not affected by the encapsulation and purification processes. PMID:19564952

  10. Facile solvothermal preparation of monodisperse gold nanoparticles and their engineered assembly of ferritin-gold nanoclusters.

    PubMed

    Choi, Jonghoon; Park, Sungwook; Stojanović, Zoran; Han, Hyung-Seop; Lee, Jongwook; Seok, Hyun Kwang; Uskoković, Dragan; Lee, Kwan Hyi

    2013-12-17

    Herein, we report a quick and simple synthesis of water-soluble gold nanoparticles using a HAuCl4 and oleylamine mixture. Oleylamine serves as a reduction agent as well as a stabilizer for nanoparticle surfaces. The particle sizes can be adjusted by modulating reaction temperature and time. Solvothermal reduction of HAuCl4 with oleylamine can be confirmed by measuring the product in Fourier transform infrared (FTIR) spectroscopy. The plasmon band shifting from yellow to red confirms a nanosized particle formation. Amide bonds on the surface of the nanoparticles formed hydrogen bonds with one another, resulting in a hydrophobic monolayer. Particles dispersed well in nonpolar organic solvents, such as in hexane or toluene, by brief sonication. Next, we demonstrated the transfer of gold nanoparticles into water by lipid capsulation using 1-myristoyl-2-hydroxy-sn-glycero-3-phosphocholine (MHPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy polyethylene glycol)-2000 (DPPE-PEG2k), and 1,2-dioleoyl-sn-glycero-3-N-{5-amino-1-carboxypentyl}iminodiacetic acid succinyl nickel salt [DGS-NTA(Ni)]. The particle concentration can be obtained using an absorbance in ultraviolet-visible (UV-vis) spectra (at 420 nm). Instrumental analyses using transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) analysis, dynamic light scattering (DLS), and FTIR confirmed successful production of gold nanoparticles and fair solubility in water. Prepared gold particles were selectively clustered via engineered ferritin nanocages that provide multiple conjugation moieties. A total of 5-6 gold nanoparticles were clustered on a single ferritin nanocage confirmed in TEM. Reported solvothermal synthesis and preparation of gold nanoclusters may serve as an efficient, alternate way of preparing water-soluble gold nanoparticles, which can be used in a wide variety of biomedical applications. PMID:24283573

  11. Preparation and characterization of novel coenzyme Q10 nanoparticles engineered from microemulsion precursors.

    PubMed

    Hsu, Cheng-Hsuan; Cui, Zhengrong; Mumper, Russell J; Jay, Michael

    2003-01-01

    The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous suspension was monitored over 7 days. The release of CoQ10 from the nanoparticles was investigated at 37 degrees C. Finally, an in vitro study of the uptake of CoQ10-NPs by mouse macrophage, J774A.1, was completed. The incorporation efficiency of CoQ10 was approximately 74% +/- 5%. Differential Scanning Calorimetry (DSC) showed that the nanoparticle was not a physical mixture of its individual components. The size of the nanoparticles increased over time if stored in aqueous suspension. However, enhanced stability was observed when the nanoparticles were stored at 4 degrees C. Storage in lyophilized form demonstrated the highest stability. The in vitro release profile of CoQ10 from the nanoparticles showed an initial period of rapid release in the first 9 hours followed by a period of slower and extended release. The uptake of CoQ10-NPs by the J774A.1 cells was over 4-fold higher than that of the CoQ10-free nanoparticles (P < .05). In conclusion, CoQ10-NPs with potential application for oral CoQ10 delivery were engineered readily from microemulsion precursors. PMID:14621964

  12. Preparation and characterization of novel coenzyme Q10 nanoparticles engineered from microemulsion precursors.

    PubMed

    Hsu, Cheng-Hsuan; Cui, Zhengrong; Mumper, Russell J; Jay, Michael

    2003-01-01

    The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous suspension was monitored over 7 days. The release of CoQ10 from the nanoparticles was investigated at 37 degrees C. Finally, an in vitro study of the uptake of CoQ10-NPs by mouse macrophage, J774A.1, was completed. The incorporation efficiency of CoQ10 was approximately 74% +/- 5%. Differential Scanning Calorimetry (DSC) showed that the nanoparticle was not a physical mixture of its individual components. The size of the nanoparticles increased over time if stored in aqueous suspension. However, enhanced stability was observed when the nanoparticles were stored at 4 degrees C. Storage in lyophilized form demonstrated the highest stability. The in vitro release profile of CoQ10 from the nanoparticles showed an initial period of rapid release in the first 9 hours followed by a period of slower and extended release. The uptake of CoQ10-NPs by the J774A.1 cells was over 4-fold higher than that of the CoQ10-free nanoparticles (P < .05). In conclusion, CoQ10-NPs with potential application for oral CoQ10 delivery were engineered readily from microemulsion precursors.

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

    PubMed Central

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

    2013-01-01

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

  14. 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.

  15. Preparation of starch-stabilized silver nanoparticles from amylose-sodium palmitate inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-stabilized silver nanoparticles were prepared from amylose-sodium palmitate complexes by first converting sodium palmitate to silver palmitate by reaction with silver nitrate and then reducing the silver ion to metallic silver. This process produced water solutions that could be dried and the...

  16. A method for top down preparation of chitosan nanoparticles and nanofibers.

    PubMed

    Wijesena, Ruchira N; Tissera, Nadeeka; Kannangara, Yasun Y; Lin, Yuan; Amaratunga, Gehan A J; de Silva, K M Nalin

    2015-03-01

    A method of top down preparation of chitosan nanoparticles and nanofibers is proposed. Chitin nanofibrils (chitin NFs) were prepared using ultrasonic assisted method from crab shells with an average diameter of 5 nm and the length less than 3 μm as analyzed by atomic force microscopy and transmission electron microscopy. These chitin nanofibers were used as the precursor material for the preparation of chitosan nanoparticles and nanofibers. The degree of deacetylation of these prepared chitosan nanostructures were found to be approximately 98%. In addition these chitosan nanostructures showed amorphous crystallinity. Transmission electron microscopic studies revealed that chitosan nanoparticles were roughly spherical in nature and had diameters less than 300 nm. These larger particles formed through self-assembly of much smaller 25 nm particles as evidenced by the TEM imaging. The diameter and the length of the chitosan nanofibers were found to be less than 100 nm and 3 μm respectively. It is envisaged that due to the cavitation effect, the deacetylated chitin nanofibers were broken down to small pieces to form seed particles. These seed particles can then be self-assembled to form larger chitosan nanoparticles.

  17. PEGylated human serum albumin (HSA) nanoparticles: preparation, characterization and quantification of the PEGylation extent

    NASA Astrophysics Data System (ADS)

    Fahrländer, E.; Schelhaas, S.; Jacobs, A. H.; Langer, K.

    2015-04-01

    Modification with poly(ethylene glycol) (PEG) is a widely used method for the prolongation of plasma half-life of colloidal carrier systems such as nanoparticles prepared from human serum albumin (HSA). However, the quantification of the PEGylation extent is still challenging. Moreover, the influence of different PEG derivatives, which are commonly used for nanoparticle conjugation, has not been investigated so far. The objective of the present study is to develop a method for the quantification of PEG and to monitor the influence of diverse PEG reagents on the amount of PEG linked to the surface of HSA nanoparticles. A size exclusion chromatography method with refractive index detection was established which enabled the quantification of unreacted PEG in the supernatant. The achieved results were confirmed using a fluorescent PEG derivative, which was detected by photometry and fluorimetry. Additionally, PEGylated HSA nanoparticles were enzymatically digested and the linked amount of fluorescently active PEG was directly determined. All the analytical methods confirmed that under optimized PEGylation conditions a PEGylation efficiency of up to 0.5 mg PEG per mg nanoparticle could be achieved. Model calculations made a ‘brush’ conformation of the PEG chains on the particle surface very likely. By incubating the nanoparticles with fetal bovine serum the reduced adsorption of serum proteins on PEGylated HSA nanoparticles compared to non-PEGylated HSA nanoparticles was demonstrated using sodium dodecylsulfate polyacrylamide gel electrophoresis. Finally, the positive effect of PEGylation on plasma half-life was demonstrated in an in vivo study in mice. Compared to unmodified nanoparticles the PEGylation led to a four times larger plasma half-life.

  18. Oleate-based hydrothermal preparation of CoFe2O4 nanoparticles, and their magnetic properties with respect to particle size and surface coating

    NASA Astrophysics Data System (ADS)

    Repko, Anton; Vejpravová, Jana; Vacková, Taťana; Zákutná, Dominika; Nižňanský, Daniel

    2015-09-01

    We present a facile and high-yield synthesis of cobalt ferrite nanoparticles by hydrothermal hydrolysis of Co-Fe oleate in the presence of pentanol/octanol/toluene and water at 180 or 220 °C. The particle size (6-10 nm) was controlled by the composition of the organic solvent and temperature. Magnetic properties were then investigated with respect to the particle size and surface modification with citric acid or titanium dioxide (leading to hydrophilic particles). The as-prepared hydrophobic nanoparticles (coated by oleic acid) had a minimum inter-particle distance of 2.5 nm. Their apparent blocking temperature (estimated as a maximum of the zero-field-cooled magnetization) was 180 K, 280 K and 330 K for the particles with size of 6, 9 and 10.5 nm, respectively. Replacement of oleic acid on the surface by citric acid decreased inter-particle distance to less than 1 nm, and increased blocking temperature by ca. 10 K. On the other hand, coating with titanium dioxide, supported by nitrilotri(methylphosphonic acid), caused increase of the particle spacing, and lowering of the blocking temperature by ca. 20 K. The CoFe2O4@TiO2 nanoparticles were sufficiently stable in water, methanol and ethanol. The particles were also investigated by Mössbauer spectroscopy and alternating-current (AC) susceptibility measurements, and their analysis with Vögel-Fulcher and power law. Effect of different particle coating and dipolar interactions on the magnetic properties is discussed.

  19. Microbial preparation of metal-substituted magnetite nanoparticles.

    PubMed

    Moon, Ji-Won; Roh, Yul; Lauf, Robert J; Vali, Hojatollah; Yeary, Lucas W; Phelps, Tommy J

    2007-07-01

    A microbial process that exploits the ability of iron-reducing microorganisms to produce copious amounts of extra-cellular metal (M)-substituted magnetite nanoparticles using akaganeite and dopants of dissolved form has previously been reported. The objectives of this study were to develop methods for producing M-substituted magnetite nanoparticles with a high rate of metal substitution by biological processes and to identify factors affecting the production of nano-crystals. The thermophilic and psychrotolerant iron-reducing bacteria had the ability to form M-substituted magnetite nano-crystals (M(y)Fe(3-y)O(4)) from a doped precursor, mixed-M iron oxyhydroxide, (M(x)Fe(1-x)OOH, x< or =0.5, M is Mn, Zn, Ni, Co and Cr). Within the range of 0.01< or =x< or =0.3, using the mixed precursor material enabled the microbial synthesis of more heavily substituted magnetite compared to the previous method, in which the precursor was pure akaganeite and the dopants were present as soluble metal salts. The mixed precursor method was especially advantageous in the case of toxic metals such as Cr and Ni. Also this new method increased the production rate and magnetic properties of the product, while improving crystallinity, size control and scalability.

  20. [Preparation of Biological Functional Magnetic Nanoparticles and Study on the Effect of Guiding Endothelial Progenitor Cells In Vitro].

    PubMed

    Ma, Baolong; Yan, Wei; Chen, Jialong; Qi, Pengkai; Li, Jianhui; Huang, Nan

    2016-02-01

    Coprecipitation method was used to prepare triiron tetroxide magnetic nanoparticles enclosed in L-DOPA, and then EDC was used to activate the carboxyl group of L-DOPA after the nanoparticles were synthesized. The carboxyl group of L-DOPA formed amide bond with specific amino on the aptamer by dehydration condensation reaction. The surfaces of magnetic nanoparticles were modified with aptamer and L-DOPA. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), nanoparticle size analysis (SEM), magnetic measurement (VSM) and other testing methods were used to detect the magnetic nanoparticles in different stages. The endothelial progeni-tor cells (EPCs) were cocultured with the surface modified magnetic nanoparticles to evaluate cell compatibility and the combination effect of nanoparticles on EPCs in a short period of time. Directional guide of the surface-modified magnetic nanoparticles to endothelial progenitor cells (EPCs) was evaluated under an applied magnetic field and simulated dynamic blood flow condition. The results showed that the prepared magnetic nanoparticles had good magnetic response, good cell compatibility within a certain range of the nanoparticle concentrations. The surface modified nanoparticles could combine with EPCs effectively in a short time, and those nanoparticles combined EPCs can be directionally guided on to a stent surface under the magnetic field in the dynamic flow environment. PMID:27382754

  1. Novel magnetic SPE method based on carbon nanotubes filled with cobalt ferrite for the analysis of organochlorine pesticides in honey and tea.

    PubMed

    Du, Zhuo; Liu, Miao; Li, Gongke

    2013-10-01

    A novel magnetic SPE method based on magnetic cobalt ferrite filled carbon nanotubes (MFCNTs) coupled with GC with electron capture detection was developed to determine organochlorine pesticides (OCPs) in tea and honey samples. The MFCNTs were prepared through the capillarity of carbon nanotubes for drawing mixed cobalt and iron nitrates solution into their inner cavity followed by heating to 550°C under Ar to form the cobalt ferrite nanoparticles. SEM images provided visible evidence of the filled cobalt ferrite nanoparticles in the multiwalled nanotubes. X-ray photoelectron spectroscopy indicated no adhesion of cobalt ferrite nanoparticles and metal salts on the outer surface of the MFCNTs. Eight OCPs were extracted with the MFCNTs. The enrichment factors were in the range of 52-68 for eight OCPs. The LODs for the eight OCPs were in the range of 1.3-3.6 ng/L. The recoveries of the OCPs for honey and tea samples were 83.2-128.7 and 72.6-111.0%, respectively. The RSDs for these samples were below 6.8%. The new method is particularly suited to extract nonpolar and weakly polar analytes from a complex matrix and could potentially be extended to other target analytes. PMID:23926126

  2. Novel magnetic SPE method based on carbon nanotubes filled with cobalt ferrite for the analysis of organochlorine pesticides in honey and tea.

    PubMed

    Du, Zhuo; Liu, Miao; Li, Gongke

    2013-10-01

    A novel magnetic SPE method based on magnetic cobalt ferrite filled carbon nanotubes (MFCNTs) coupled with GC with electron capture detection was developed to determine organochlorine pesticides (OCPs) in tea and honey samples. The MFCNTs were prepared through the capillarity of carbon nanotubes for drawing mixed cobalt and iron nitrates solution into their inner cavity followed by heating to 550°C under Ar to form the cobalt ferrite nanoparticles. SEM images provided visible evidence of the filled cobalt ferrite nanoparticles in the multiwalled nanotubes. X-ray photoelectron spectroscopy indicated no adhesion of cobalt ferrite nanoparticles and metal salts on the outer surface of the MFCNTs. Eight OCPs were extracted with the MFCNTs. The enrichment factors were in the range of 52-68 for eight OCPs. The LODs for the eight OCPs were in the range of 1.3-3.6 ng/L. The recoveries of the OCPs for honey and tea samples were 83.2-128.7 and 72.6-111.0%, respectively. The RSDs for these samples were below 6.8%. The new method is particularly suited to extract nonpolar and weakly polar analytes from a complex matrix and could potentially be extended to other target analytes.

  3. Preparation and characterization of vanadium-doped ZnO nanoparticles for environmental application.

    PubMed

    Chang, Hankwon; Nikolov, Jonian; Kim, Sun-Kyung; Jang, Hee Dong; Lim, Seng; Kim, Dong-Jin

    2011-01-01

    Vanadium-doped ZnO nanoparticles (ZnO:V) were prepared via flame spray pyrolysis (FSP) from a mixed aqueous solution of zinc hydroxide and vanadyl (IV) acetylacetonate. The morphological, structural and optical properties of the ZnO:V photocatalyst were characterized via transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and UV-visible diffused reflection spectrum (DRS). The photocatalytic activity of ZnO:V was evaluated via photocatalytic degradation of methylene blue (MB). The results showed that the hexagonal wurtzite-structured ZnO:V nanoparticles were successfully synthesized via FSP. The morphology of the as-prepared nanoparticles was polyhedral and non-hollow. The average diameter of ZnO:V, which was calculated from BET result, was 11.7 nm when the molar ratio of V/Zn was 0.1. The maximum decomposition of MB by the ZnO:V nanoparticles was 99.4% after 180 min under UV irradiation, whereas the decomposition of MB by the pure ZnO nanoparticles was 96.6%. PMID:21446523

  4. A convenient method to prepare emulsified polyacrylate nanoparticles from powders [corrected] for drug delivery applications.

    PubMed

    Garay-Jimenez, Julio C; Turos, Edward

    2011-08-01

    We describe a method to obtain purified, polyacrylate nanoparticles in a homogeneous powdered form that can be readily reconstituted in aqueous media for in vivo applications. Polyacrylate-based nanoparticles can be easily prepared by emulsion polymerization using a 7:3 mixture of butyl acrylate and styrene in water containing sodium dodecyl sulfate as a surfactant and potassium persulfate as a water-soluble radical initiator. The resulting emulsions contain nanoparticles measuring 40-50 nm in diameter with uniform morphology, and can be purified by centrifugation and dialysis to remove larger coagulants as well as residual surfactant and monomers associated with toxicity. These purified emulsions can be lyophilized in the presence of maltose (a non-toxic cryoprotectant) to provide a homogeneous dried powder, which can be reconstituted as an emulsion by addition of an aqueous diluent. Dynamic light scattering and microbiological experiments were carried out on the reconstituted nanoparticles. This procedure allows for ready preparation of nanoparticle emulsions for drug delivery applications. PMID:21704525

  5. Preparation and characterization of polymer nanocomposites coated magnetic nanoparticles for drug delivery applications

    NASA Astrophysics Data System (ADS)

    Prabha, G.; Raj, V.

    2016-06-01

    In the present research work, the anticancer drug 'curcumin' is loaded with Chitosan (CS)-polyethylene glycol (PEG)-polyvinylpyrrolidone (PVP) (CS-PEG-PVP) polymer nanocomposites coated with superparamagnetic iron oxide (Fe3O4) nanoparticles. The system can be used for targeted and controlled drug delivery of anticancer drugs with reduced side effects and greater efficiency. The prepared nanoparticles were characterized by Fourier transmission infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Curcumin drug loaded Fe3O4-CS, Fe3O4-CS-PEG and Fe3O4-CS-PEG-PVP nanoparticles exhibited the mean particle size in the range of 183-390 nm with a zeta potential value of 26-41 mV as measured using Malvern Zetasizer. The encapsulation efficiency, loading capacity and in-vitro drug release behavior of curcumin drug loaded Fe3O4-CS, Fe3O4-CS-PEG and Fe3O4-CS-PEG-PVP nanoparticles were studied using UV spectrophotometer. Besides, the cytotoxicity of the prepared nanoparticles using MTT assay was also studied. The curcumin drug release was examined at different pH medium and it was proved that the drug release depends upon the pH medium in addition to the nature of matrix.

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

    SciTech Connect

    Jegatha Christy, A.; Umadevi, M.

    2013-10-15

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

  7. Preparation and characterization of triclosan nanoparticles intended to be used for the treatment of acne.

    PubMed

    Domínguez-Delgado, Clara Luisa; Rodríguez-Cruz, Isabel Marlen; Escobar-Chávez, José Juan; Calderón-Lojero, Iván Omar; Quintanar-Guerrero, David; Ganem, Adriana

    2011-09-01

    This work focuses on the preparation and characterization of nanoparticles containing triclosan. Additionally, in vitro percutaneous permeation of triclosan through pig ear skin was performed, and comparisons were made with two commercial formulations: An o/w emulsion and a solution, intended for the treatment of acne. The nanoparticle suspensions were prepared by the emulsification-diffusion by solvent displacement method, using Eudragit® E 100 as polymer. All batches showed a size smaller than 300 nm and a positive Zeta potential, high enough (20-40 mV) to ensure a good physical stability. Differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) studies suggested that triclosan was molecularly dispersed in the nanoparticle batches containing up to 31% of triclosan, with good encapsulation efficiency (95.9%). The results of the in vitro permeation studies showed the following order for the permeability coefficients: Solution>cream≈nanoparticles; while for the amount retained in the skin, the order was as follows: cream>nanoparticles≈solution. Nanoparticles, being free of surfactants or other potentially irritant agents, can be a good option for the delivery of triclosan to the skin, representing a good alternative for the treatment of acne.

  8. Preparation of starch nanoparticles in water in oil microemulsion system and their drug delivery properties.

    PubMed

    Wang, Xinge; Chen, Haiming; Luo, Zhigang; Fu, Xiong

    2016-03-15

    In this research, 1-hexadecyl-3-methylimidazolium bromide C16mimBr/butan-1-ol/cyclohexane/water ionic liquid microemulsion was prepared. The effects of n-alkyl alcohols, alkanes, water content and temperature on the properties of microemulsion were studied by dilution experiment. The microregion of microemulsion was identified by pseudo-ternary phase diagram and conductivity measurement. Then starch nanoparticles were prepared by water in oil (W/O) microemulsion-cross-linking methods with C16mimBr as surfactant. Starch nanoparticles with a mean diameter of 94.3nm and narrow size distribution (SD=3.3) were confirmed by dynamic light scattering (DLS). Scanning electron microscope (SEM) data revealed that starch nanoparticles were spherical granules with the size about 60nm. Moreover the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) demonstrated the formation of cross-linking bonds in starch molecules. Finally, the drug loading and releasing properties of starch nanoparticles were investigated with methylene blue (MB) as drug model. This work may provide an efficient pathway to synthesis starch nanoparticles. PMID:26794752

  9. Preparation of starch nanoparticles in water in oil microemulsion system and their drug delivery properties.

    PubMed

    Wang, Xinge; Chen, Haiming; Luo, Zhigang; Fu, Xiong

    2016-03-15

    In this research, 1-hexadecyl-3-methylimidazolium bromide C16mimBr/butan-1-ol/cyclohexane/water ionic liquid microemulsion was prepared. The effects of n-alkyl alcohols, alkanes, water content and temperature on the properties of microemulsion were studied by dilution experiment. The microregion of microemulsion was identified by pseudo-ternary phase diagram and conductivity measurement. Then starch nanoparticles were prepared by water in oil (W/O) microemulsion-cross-linking methods with C16mimBr as surfactant. Starch nanoparticles with a mean diameter of 94.3nm and narrow size distribution (SD=3.3) were confirmed by dynamic light scattering (DLS). Scanning electron microscope (SEM) data revealed that starch nanoparticles were spherical granules with the size about 60nm. Moreover the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) demonstrated the formation of cross-linking bonds in starch molecules. Finally, the drug loading and releasing properties of starch nanoparticles were investigated with methylene blue (MB) as drug model. This work may provide an efficient pathway to synthesis starch nanoparticles.

  10. Enhanced Oral Delivery of Docetaxel Using Thiolated Chitosan Nanoparticles: Preparation, In Vitro and In Vivo Studies

    PubMed Central

    Saremi, Shahrooz; Kebriaeezadeh, Abbas; Ostad, Seyed Nasser; Atyabi, Fatemeh

    2013-01-01

    The aim of this study was to evaluate a nanoparticulate system with mucoadhesion properties composed of a core of polymethyl methacrylate surrounded by a shell of thiolated chitosan (Ch-GSH-pMMA) for enhancing oral bioavailability of docetaxel (DTX), an anticancer drug. DTX-loaded nanoparticles were prepared by emulsion polymerization method using cerium ammonium nitrate as an initiator. Physicochemical properties of the nanoparticles such as particle size, size distribution, morphology, drug loading, and entrapment efficiency were characterized. The pharmacokinetic study was carried out in vivo using wistar rats. The half-life of DTX-loaded NPs was about 9 times longer than oral DTX used as positive control. The oral bioavailability of DTX was increased to 68.9% for DTX-loaded nanoparticles compared to 6.5% for positive control. The nanoparticles showed stronger effect on the reduction of the transepithelial electrical resistance (TEER) of Caco-2 cell monolayer by opening the tight junctions. According to apparent permeability coefficient (Papp) results, the DTX-loaded NPs showed more specific permeation across the Caco-2 cell monolayer in comparison to the DTX. In conclusion, the nanoparticles prepared in this study showed promising results for the development of an oral drug delivery system for anticancer drugs. PMID:23971023

  11. Comparison and functionalization study of microemulsion-prepared magnetic iron oxide nanoparticles.

    PubMed

    Okoli, Chuka; Sanchez-Dominguez, Margarita; Boutonnet, Magali; Järås, Sven; Civera, Concepción; Solans, Conxita; Kuttuva, Gunaratna Rajarao

    2012-06-01

    Magnetic iron oxide nanoparticles (MION) for protein binding and separation were obtained from water-in-oil (w/o) and oil-in-water (o/w) microemulsions. Characterization of the prepared nanoparticles have been performed by TEM, XRD, SQUID magnetometry, and BET. Microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) with sizes ranging from 2 to 10 nm were obtained. Study on the magnetic properties at 300 K shows a large increase of the magnetization ~35 emu/g for w/o-ME-MION with superparamagnetic behavior and nanoscale dimensions in comparison with o/w-ME-MION (10 emu/g) due to larger particle size and anisotropic property. Moringa oleifera coagulation protein (MOCP) bound w/o- and o/w-ME-MION showed an enhanced performance in terms of coagulation activity. A significant interaction between the magnetic nanoparticles and the protein can be described by changes in fluorescence emission spectra. Adsorbed protein from MOCP is still retaining its functionality even after binding to the nanoparticles, thus implying the extension of this technique for various applications. PMID:22578053

  12. Preparation of solid lipid nanoparticles by a solvent emulsification-diffusion technique.

    PubMed

    Trotta, Michele; Debernardi, Francesca; Caputo, Otto

    2003-05-12

    A preparation method for nanoparticles based on the emulsification of a butyl lactate or benzyl alcohol solution of a solid lipid in an aqueous solution of different emulsifiers, followed by dilution of the emulsion with water, was used to prepare glyceryl monostearate nanodispersions with narrow size distribution. To increase the lipid load the process was conducted at 47+/-2 degrees C and in order to reach submicron size a high-shear homogenizer was used. Particle size of the solid lipid nanoparticles (SLN) was affected by using different emulsifiers and different lipid loads. By using lecithin and taurodeoxycholic acid sodium salt, on increasing the GMS percentage from 2.5 to 10% an increase of the mean diameter from 205 to 695 nm and from 320 to 368nm was observed for the SLN prepared using benzyl alcohol and butyl lactate, respectively. Transmission electron micrographs of SLN reveal nanospheres with a smooth surface.

  13. Preparation of BaZrO3 nanoparticles using a solvothermal reaction

    NASA Astrophysics Data System (ADS)

    Nakashima, Kouichi; Goto, Takayuki; Iwatsuki, Shougo; Kera, Masatoshi; Fujii, Ichiro; Wada, Satoshi

    2011-10-01

    Barium zirconate (BaZrO3) nanoparticles were successfully prepared by a solvothermal reaction. These were synthesized by a solvothermal method at 230°C -240°C for 18 h using a mixture solution of ethanol and 2-metoxy-thanol as the reaction medium. The prepared particles were collected using a centrifugal separator. The X-ray diffraction (XRD) measurement confirmed the presence of perovskite BaZrO3 particles. The scanning electron microscopy (SEM) observations revealed that the particles were composed of highly dispersed nanoparticles. The results of our study indicate that the addition of water to the reaction medium is an important for the preparation of a perovskite structure and control of the size of the BaZrO3.

  14. Preparation and characterization of Tamoxifen citrate loaded nanoparticles for breast cancer therapy

    PubMed Central

    Maji, Ruma; Dey, Niladri Shekhar; Satapathy, Bhabani Sankar; Mukherjee, Biswajit; Mondal, Subhasish

    2014-01-01

    Background Four formulations of Tamoxifen citrate loaded polylactide-co-glycolide (PLGA) based nanoparticles (TNPs) were developed and characterized. Their internalization by Michigan Cancer Foundation-7 (MCF-7) breast cancer cells was also investigated. Methods Nanoparticles were prepared by a multiple emulsion solvent evaporation method. Then the following studies were carried out: drug-excipients interaction using Fourier transform infrared spectroscopy (FTIR), surface morphology by field emission scanning electron microscopy (FESEM), zeta potential and size distribution using a Zetasizer Nano ZS90 and particle size analyzer, and in vitro drug release. In vitro cellular uptake of nanoparticles was assessed by confocal microscopy and their cell viability (%) was studied. Results No chemical interaction was observed between the drug and the selected excipients. TNPs had a smooth surface, and a nanosize range (250–380 nm) with a negative surface charge. Drug loadings of the prepared particles were 1.5%±0.02% weight/weight (w/w), 2.68%±0.5% w/w, 4.09%±0.2% w/w, 27.16%±2.08% w/w for NP1–NP4, respectively. A sustained drug release pattern from the nanoparticles was observed for the entire period of study, ie, up to 60 days. Further, nanoparticles were internalized well by the MCF-7 breast cancer cells on a concentration dependent manner and were present in the cytoplasm. The nucleus was free from nanoparticle entry. Drug loaded nanoparticles were found to be more cytotoxic than the free drug. Conclusion TNPs (NP4) showed the highest drug loading, released the drug in a sustained manner for a prolonged period of time and were taken up well by the MCF-7 breast cancer cell line in vitro. Thus the formulation may be suitable for breast cancer treatment due to the good permeation of the formulation into the breast cancer cells. PMID:25028549

  15. Nickel nanoparticles with hcp structure: Preparation, deposition as thin films and application as electrochemical sensor.

    PubMed

    Neiva, Eduardo G C; Oliveira, Marcela M; Marcolino, Luiz H; Zarbin, Aldo J G

    2016-04-15

    Hexagonal close packed (hcp) nickel nanoparticles stabilized by polyvinylpyrrolidone (PVP) were synthesized through the thermal treatment of face centered cubic (fcc) nickel nanoparticles. Controlling both the temperature of the heat treatment and the amount of PVP was possible the control of the hcp/fcc rate in the samples, where the higher Ni/PVP ratio produces only the hcp-nickel phase (average size of 8.9 nm) highly stable in air. The crystalline structure, the presence of PVP, the size of the nanoparticles and the stability of the hcp-nickel were confirmed using X-ray diffractometry, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy, scanning electron microscopy and thermogravimetric analysis. Thin films of hcp and fcc nickel nanoparticles were prepared through a biphasic system and deposited over indium-doped tin oxide (ITO) substrates, which were electrochemically characterized and applied as glycerol amperometric sensors in NaOH medium. Parameters as the number of cycles applied and the scan rate were evaluated and indicate that hcp nickel nanoparticles are more reactive to form Ni(OH)2 and lead to more electroactive Ni(OH)2 structure. The hcp nickel nanoparticles-modified electrode showed the best sensitivity (0.258 μA L μmol(-1)) and detection limit (2.4 μmol L(-1)) toward glycerol. PMID:26821149

  16. Preparation of pH-Sensitive Dextran Nanoparticle for Doxorubicin Delivery.

    PubMed

    Wang, Bi; Liu, Peng; Shi, Bihua; Gao, Jihua; Gong, Ping

    2015-04-01

    One of challenge for cancer therapy is efficient delivery of anticancer agents into tumor sites to increase efficiency of drugs and reduce side effects. To overcome this challenge, we designed pH- sensitive doxorubicin prodrug (DEX-PEI-DOX) nanoparticles based on dextran-poly(ethylene imine) copolymers (DEX-PEI). The DEX-PEI-DOX conjugates were conveniently prepared by grafting PEI to dextran, and then anticancer drug doxorubicin (DOX) were conjugated to DEX-PEI through acid cleavable cis-aconityl bonds. The experiments of dynamic light scattering (DLS) and transmission electron microscopy (TEM) represented that size of dextran nanoparticles was about 120 nm with uniform spherical shape. In vitro drug release from self-assembled nanoparticles was dependent on the pH of medium due to the cis-aconityl linkage. Confocal images revealed that dextran based pH-sensitive DOX delivery nanoparticle could enter into Human breast carcinoma (MCF-7) cells easily. Therapeutic efficacy against MCF-7 cells in vitro was evaluated through MTT assays and the results showed that dextran nanoparticle had obvious anticancer ability. All above results indicated this pH-sensitive DOX-loaded nanoparticles system would be a useful candidate for cancer therapy. PMID:26353472

  17. Application of a new coordination compound for the preparation of AgI nanoparticles

    SciTech Connect

    Mohandes, Fatemeh; Salavati-Niasari, Masoud

    2013-10-15

    Graphical abstract: Silver iodide nanoparticles have been sonochemically synthesized by using silver salicylate complex, [Ag(HSal)], as silver precursor. A series of control experiments were carried out to investigate the effects of solvent, surfactant concentration, sonication time and temperature on the morphology of AgI nanostructures. - Highlights: • Silver salicylate as a new precursor was applied to fabricate γ-AgI nanoparticles. • To further decrease the particle size of AgI, SDS was used as surfactant. • The effect of preparation parameters on the particle size of AgI was investigated. - Abstract: AgI nanoparticles have been sonochemically synthesized by using silver salicylate, [Ag(HSal)], as silver precursor. To investigate the effects of solvent, surfactant concentration, sonication time and temperature on the morphology of AgI nanostructures, several experiments were carried out. The products were characterized by SEM, TEM, XRD, TGA/DTA, UV–vis, and FT-IR. Based on the experimental findings in this research, it was found that the size of AgI nanoparticles was dramatically dependent on the silver precursor, sonochemical irradiation, and surfactant concentration. Sodium dodecyl sulfate (SDS) was applied as surfactant. When the concentration of SDS was 0.055 mM, very uniform sphere-like AgI nanoparticles with grain size of about 25–30 nm were obtained. These results indicated that the high concentration of SDS could prevent the aggregation between colloidal nanoparticles due to its steric hindrance effect.

  18. Preparation and characterization of a thermostable enzyme (Mn-SOD) immobilized on supermagnetic nanoparticles.

    PubMed

    Song, Chongfu; Sheng, Liangquan; Zhang, Xiaobo

    2012-10-01

    Superoxide dismutase (SOD) has been widely applied in medical treatments, cosmetic, food, agriculture, and chemical industries. In industry, the immobilization of enzymes can offer better stability, feasible continuous operations, easy separation and reusing, and significant decrease of the operation costs. However, little attention has focused on the immobilization of the SOD, as well as the immobilization of thermostable enzymes. In this study, the recombinant thermostable manganese superoxide dismutase (Mn-SOD) of Thermus thermophilus wl was purified and covalently immobilized onto supermagnetic 3-APTES-modified Fe(3)O(4)@SiO(2) nanoparticles using glutaraldehyde method to prepare the Mn-SOD bound magnetic nanoparticles. The Mn-SOD nanoparticles were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer analysis. The results indicated that the diameter of Mn-SOD nanoparticles was 40 (± 5) nm, and its saturation magnetization value was 27.9 emu/g without remanence or coercivity. By comparison with the free Mn-SOD, it was found that the immobilized Mn-SOD on nanoparticles exhibited better resistance to temperature, pH, metal ions, enzyme inhibitors, and detergents. The results showed that the immobilized Mn-SOD on nanoparticles could be reused ten times without significant decrease of enzymatic activity. Therefore, our study presented a novel strategy for the immobilization of thermostable Mn-SOD and for the application of thermostable enzymes. PMID:22237672

  19. Solvothermal synthesis of CZTS nanoparticles in ethanol: Preparation and characterization

    NASA Astrophysics Data System (ADS)

    Yan, Xinlong; Hu, Xiaoyan; Komarneni, Sridhar

    2015-05-01

    In this work, a low-cost, non-toxic and convenient one-pot solvothermal route to synthesize Cu2ZnSnS4 (CZTS) nanoparticles is reported. The effects of solvothermal temperature and reaction time on the structure, morphology and optical properties of the as-synthesized product were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX) measurements and X-ray photoelectron spectroscopy (XPS). The results showed that the crystallinity of the CZTS powders was influenced by the solvothermal temperature and reaction time. The band gap of selected CZTS samples was near the optimum value for photovoltaic solar conversion in a single-band-gap device.

  20. Preparation of polylysine-modified superparamagnetic iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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