Sample records for ferrite nanoparticles prepared

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

    Microsoft Academic Search

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

    2006-01-01

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

  2. Preparation and Characterization of Hexagonal W-type Barium Ferrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Trif, László; Tolnai, Gyula; Sajó, István; Kálmán, Erika

    New chemical synthesis procedure for preparation of nickel-zinc doped W-type hexagonal, nickel-zinc doped barium ferrite nanoparticles has been developed, using the nitrate-citrate sol-gel auto-combustion method (NCSAM). The crystalline phase attributes, microstructure, morphology, thermal behavior of the as-burnt phase and the sintered powders were characterized using XRD, SEM, TG-DTA, FT-IR measurements. The pure W-type ferrite phase is formed during 4 h annealing at a temperature of 1 200 °C.

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

    Microsoft Academic Search

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

    2006-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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 ?-Fe2O3 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. Cobalt and magnesium ferrite nanoparticles: preparation using liquid foams as templates and their magnetic characteristics.

    PubMed

    Bala, Tanushree; Sankar, C Raj; Baidakova, Marina; Osipov, Vladimir; Enoki, Toshiaki; Joy, P A; Prasad, B L V; Sastry, Murali

    2005-11-01

    An easy and convenient method for the synthesis of cobalt and magnesium ferrite nanoparticles is demonstrated using liquid foams as templates. The foam is formed from an aqueous mixture of an anionic surfactant and the desired metal ions, where the metal ions are electrostatically entrapped by the surfactant at the thin borders between the foam bubbles and their junctions. The hydrolysis is carried out using alkali resulting in the formation of desired nanoparticles, with the foam playing the role of a template. However, in the formation of ferrites with the formula MFe(2)O(4), where the metal ion and iron possess oxidation states of +2 and +3, respectively, forming a foam from a 1:2 mixture of the desired ionic solutions would lead to a foam composition at variance with the original solution mixture because of greater electrostatic binding of ions possessing a greater charge with the surfactant. In our procedure, we circumvent this problem by preparing the foam from a 1:2 mixture of M(2+) and Fe(2+) ions and then utilizing the in situ conversion of Fe(2+) to Fe(3+) under basic conditions inside the foam matrix to get the desired composition of the metal ions with the required oxidation states. The fact that we could prepare both CoFe(2)O(4) and MgFe(2)O(4) particles shows the vast scope of this method for making even multicomponent oxides. The magnetic nanoparticles thus obtained exhibit a good crystalline nature and are characterized by superparamagnetic properties. The magnetic features observed for CoFe(2)O(4) and MgFe(2)O(4) nanoparticles are well in accordance with the expected behaviors, with CoFe(2)O(4) particles showing higher blocking temperatures and larger coercivities. These features can easily be explained by the contribution of Co(2+) sites to the magnetocrystalline anisotropy and the absence of the same from the Mg(2+) ions. PMID:16262331

  6. Cobalt and magnesium ferrite nanoparticles: Preparation using liquid foams as templates and their magnetic characteristics

    Microsoft Academic Search

    Tanushree Bala; C. Raj Sankar; Marina Baidakova; Vladimir Osipov; Toshiaki Enoki; P. A. Joy; B. L. V. Prasad; Murali Sastry

    2005-01-01

    An easy and convenient method for the synthesis of cobalt and magnesium\\u000a ferrite nanoparticles is demonstrated using liquid foams as templates.\\u000a The foam is formed from an aqueous mixture of an anionic surfactant and\\u000a the desired metal ions, where the metal ions are electrostatically\\u000a entrapped by the surfactant at the thin borders between the foam bubbles\\u000a and their junctions. The

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

    Microsoft Academic Search

    Neil J.. Shirtcliffe; Simon Thompson; Eoin S. O’Keefe; Steve Appleton; Carole C.. Perry

    2007-01-01

    Aluminium doped barium and strontium hexaferrite nanoparticles BaAlxFe(12?x)O19 and SrAlxFe(12?x)O19 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

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

    SciTech Connect

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

    2013-02-15

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

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

    SciTech Connect

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

    2007-02-15

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  12. Structural investigations and magnetic properties of cobalt ferrite nanoparticles prepared by sol gel auto combustion method

    NASA Astrophysics Data System (ADS)

    Toksha, B. G.; Shirsath, Sagar E.; Patange, S. M.; Jadhav, K. M.

    2008-09-01

    Morphological and magnetic characteristics of cobalt ferrite nanoparticles synthesized by sol-gel auto combustion method using nitrates of respective metal ions have been studied. X-ray diffraction pattern was indexed by a Rietveld program to calculate accurate unit cell dimension. A Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 11-40 nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 25 nm. A very large coercivity (10.2 kOe) is observed on cooling down to 77 K while typical blocking effects are observed below about 260 K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles. Mossbauer spectra recorded at room temperature is a sextet indicating that there is a strong magnetic coupling and increase in sintering temperature from 570 ?C to 800 ?C do not affect Mossbauer parameters.

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

    Microsoft Academic Search

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

    2007-01-01

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

  14. 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 [Al. I. Cuza' University, Faculty of Physics, 11A Blvd.Copou, 700506, Iasi (Romania)

    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.

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

    Microsoft Academic Search

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

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

  16. Low temperature chemical synthesis of ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  17. Nanoparticle composites having structural intergrowths of hexaferrite and spinel ferrites prepared by gel-to-crystallite conversion and their magnetic properties

    NASA Astrophysics Data System (ADS)

    Sudakar, C.; Subbanna, G. N.; Kutty, T. R. N.

    2004-01-01

    Nanoparticle composites of spinel (S) and hexaferrite (W or Y phase) in different ratios were prepared by a wet-chemical process of gel-to-crystallite conversion. The compositions were selected on the line connecting W-S or Y-S in the BaO-NiO-Fe 2O 3 ternary phase diagram. High-resolution electron micrographs of these crystallites show coherent intergrowth features involving hexaferrite and spinel ferrite structural blocks. Intergrown nickel ferrite blocks appear randomly, with different insertion widths (1-20 nm) with increase in the spinel ferrite content, within the hexaferrite matrix corresponding to M- or Y-type primitive repeat for the composites. Thermomagnetic curves clearly reveal the composite nature of the particle by way of two ferrite components. The specific magnetization of the composites show typical additive rule. With increasing spinel content, coercivity decreases continuously for the compositions on the W-S line, whereas it goes through a maximum on the Y-S line. This is explained on the basis of spin reorientation within the domains for intermediate compositions on the Y-S line. The effective easy direction of magnetization in composites will lie in between the easy direction <1 1 1> in cubic nickel ferrite and the easy plane (0 0 1) in Y-Ni 2. The increase in coercivity for intermediate compositions is due to the increase in anisotropy field for these composites.

  18. Preparation and Properties of Thin Ferrite Films

    Microsoft Academic Search

    E. Banks; N. H. Riederman; H. W. Schleuning; L. M. Silber

    1961-01-01

    Thin films of ferrites, of the order of 1000 A thickness, have been prepared by vacuum evaporation of the metals, and subsequent high-temperature oxidation. Films of iron, nickel, cobalt, magnesium, and copper ferrites, mixed ferrites, and mixed ferrite-aluminates, as well as yttrium iron garnet, have been prepared. X-ray powder diffractometry indicates that the ferrite films are single-phase spinels, while the

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

    Microsoft Academic Search

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

    2005-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Luo, H.; Rai, B. K.; Mishra, S. R.; Nguyen, V. V.; Liu, J. P.

    2012-08-01

    Highly Al3+ ion doped nanocrystalline SrFe12-xAlxO19 (0?x?12), were prepared by the auto-combustion method and heat treated in air at 1100 °C for 12 h. The phase identification of the powders performed using x-ray diffraction show presence of high-purity hexaferrite phase and absence of any secondary phases. With Al3+ doping, the lattice parameters decrease due to smaller Al3+ ion replacing Fe3+ ions. Morphological analysis performed using transmission electron microscope show growth of needle shaped ferrites with high aspect ratio at Al3+ ion content exceeding x?2. Al3+ substitution modifies saturation magnetization (MS) and coercivity (HC). The room temperature MS values continuously reduced while HC value increased to a maximum value of 18,100 Oe at x=4, which is an unprecedented increase (˜321%) in the coercivity as compared to pure Sr-Ferrite. However, at higher Al3+ content x>4, a decline in magnetization and coercivity has been observed. The magnetic results indicate that the best results for applications of this ferrite will be obtained with an iron deficiency in the stoichiometric formulation.

  1. Magnetocaloric effect in ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Rebar, D.

    2005-03-01

    Miniaturization of the electronic devices for space, military and consumer applications requires cooling devices to be fabricated on a chip for power efficient, noise-free operations. Refrigeration based on the adiabatic-demagnetization has been used for several decades for cooling down to sub-kelvin temperatures. Superparamagnetic particles also hold tremendous potential towards this application. We have studied magnetocaloric effect (MCE) properties in chemically synthesized ferrite nanoparticles over a broad range in temperature and magnetic fields. Nanoparticles investigated include Fe3O4 (average size = 8 nm, synthesized using co-precipitation method), MnZnFe2O4 (average size = 15 nm, synthesized using reverse-micelle technique) and CoFe2O4 (average size 8 nm, synthesized using pyrolectic technique). The magnetic entropy change was calculated by applying Maxwell's relations to magnetization vs magnetic field curves at various temperatures. Our results indicate that the single-domain particles in their superparamagnetic state show a considerable entropy change near the blocking temperature. The influence of interactions on MCE effect will also be discussed. Work supported by NSF through Grant No. CTS-0408933

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

    PubMed Central

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

    2009-01-01

    Aim: MgFe2O4 magnetic nanoparticle composed of As2O3 (As2O3-MNPs) were prepared and their in vitro and in vivo characteristics were studied. Methods: The solvent-displacement method was applied for preparation of the nanoparticle using Poly-D,L-lactic-co-glycolic acid(PLGA). The characteristics studies of the products included magnetic response, morphology (transmission electron microscopy and scanning electron microscopy), entrapment efficiency, drug loading, particle sizes, zeta potential, in vitro drug release and tissue magnetic targeting. Nanoparticle cytotoxicity to Saos-2 cells was investigated using the MTT assay. To guide the external magnetic field in the liver, the concentration of As2O3 in the liver and kidney was measured using an atomic fluorescence spectrometer after injecting As2O3-MNPs into the caudal veins of mice. Results: The As2O3-MNPs were approximately spherical. The average diameter, drug loading, entrapment efficiency and zeta potential of As2O3-MNPs were 109.9 nm, 10.08%, 82.16%, and ?14.33 mV, respectively. The specific saturation magnetism was 8.65 emu/g. In vivo, the concentration of As2O3 in the liver was significantly higher than that in the non-magnetic group. While the concentration of As2O3 in the kidney was lower than that in the non-magnetic group. The Cmax in liver tissue in the magnetic group was 30.65 ?g/g, which was 4.17 times the drug concentration in the same group in kidney tissue (7.35 ?g/g) and 2.88 times the concentration of drug (10.66 ?g/g) in the liver tissue of the non-magnetic group. Conclusion: The PLGA polymer-loaded magnetic nanoparticle composed of arsenic trioxide can be magnetically targeted well and applied in biomedicine. PMID:19960013

  3. Study of DNA interaction with cobalt ferrite nanoparticles.

    PubMed

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

    2011-03-01

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

  4. 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.

  5. Microwave assisted low temperature synthesis of MnZn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhenyu, Lai; Guangliang, Xu; Yalin, Zheng

    2007-01-01

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

  6. Synthesis of strontium ferrite nanoparticles by coprecipitation in the presence of polyacrylic acid

    Microsoft Academic Search

    Dong-Hwang Chen; Yuh-Yuh Chen

    2002-01-01

    Strontium ferrite nanoparticles were prepared by coprecipitation in a PAA aqueous solution. The average diameter of the mixed hydroxide precipitates was 3.1nm. From the thermal analysis by TGA\\/DTA and the phase analysis by XRD, it was shown that the appropriate molar ratio of Sr\\/Fe in aqueous solution was 1\\/8 and the precursor could yield pure strontium ferrite after calcination at

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

    Microsoft Academic Search

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

    2007-01-01

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

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

    Microsoft Academic Search

    Xuebo Cao; Li Gu

    2005-01-01

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

  9. Field-Induced Microwave Absorption in Ni Ferrite Nanoparticles

    Microsoft Academic Search

    Pablo Hernandez-Gomez; J. Muoz; Manuel A. Valente

    2010-01-01

    Ferrite nanoparticles are in the last years a matter of strong interest due to the fact that nanoscale materials possess size-dependent optical, electronic, magnetic, thermal, mechanical, and chemical properties that are comparable to or superior to those of bulk material counterparts, as well as its potential applications in sensors or microwave devices. Nickel ferrites, which are well-known technological materials in

  10. Optimizing hysteretic power loss of magnetic ferrite nanoparticles

    E-print Network

    Chen, Ritchie

    2013-01-01

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

  11. Cation distribution in copper ferrite nanoparticles of ferrofluids: A synchrotron XRD and EXAFS investigation

    Microsoft Academic Search

    J. A. Gomes; M. H. Sousa; G. J. da Silva; F. A. Tourinho; J. Mestnik-Filho; R. Itri; G. de M. Azevedo; J. Depeyrot

    2006-01-01

    This work reports on the structural characterization of a copper ferrite nanoparticle sample, prepared by coprecipitation method, on both short (EXAFS) and long range (XRD) scales. The diffractograms obtained at room temperature were used for Rietveld refinement to determine the lattice parameters, the oxygen position, the mean size of the nanomaterial and the inversion degree, indicating the existence of a

  12. Magnetic properties of cobalt ferrite nanoparticles synthesized by sol-gel method

    NASA Astrophysics Data System (ADS)

    George, T.; Sunny, A. T.; Varghese, T.

    2015-02-01

    Cobalt ferrite nanoparticles of average size 18 nm are synthesized by sol-gel method and investigated the magnetic properties. The saturation magnetization value calculated from vibration sample magnetometer (VSM) studies for CoFe2O4 is lower than the reported value for the bulk. The magnetization curves demonstrate a trend towards the superparamagnetic behavior of the as-prepared CoFe2O4 nanoparticles. The microwave magnetic parameters show a decreasing trend with the increase of frequency.

  13. Simple preparation and characterization of nickel ferrite nanocrystals by a thermal treatment method

    Microsoft Academic Search

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

    2011-01-01

    Nickel ferrite nanocrystals were prepared from an aqueous solution containing metal nitrates and poly (vinyl pyrrolidone) (PVP) as a capping agent. To stabilize the particles, they were thermally treated at various temperatures from 623 to 823K at which calcination occurred, thereby stabilizing the particles, controlling the growth of the nanoparticles, preventing their agglomeration, and creating a uniform distribution of particle

  14. Synthesis of cobalt ferrite nanoparticles using combustion waves

    NASA Astrophysics Data System (ADS)

    de Biasi, R. S.; Figueiredo, A. B. S.; Fernandes, A. A. R.; Larica, C.

    2007-10-01

    Nanocrystalline particles of cobalt ferrite (CoFe 2O 4) were prepared by a combustion wave method, based on the Self-propagating High temperature Synthesis technique (SHS), using iron nitrate, Fe(NO 3) 3?9H 2O, cobalt nitrate, Co(NO 3) 2?6H 2O, and glycine, C 2H 5NO 2. The average particle size, determined by means of X-ray diffraction, was found to depend on the glycine-nitrate ratio and varied between 2.7 and 17 nm. By measuring at several temperatures the relative intensity of the Mössbauer spectra due to superparamagnetic particles and to ferrimagnetic particles, we determined the size distribution of the nanoparticles in one of the samples. It was found to be a log-normal distribution with a most probable diameter Dm=1.8 nm and a full width at half-height ?D=2.6 nm.

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

    PubMed

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

    2013-03-01

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

  16. Investigation of structural, thermal and magnetic properties of cadmium substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Venkata Reddy, Ch.; Byon, Chan; Narendra, B.; Baskar, D.; Srinivas, G.; Shim, Jaesool; Prabhakar Vattikuti, S. V.

    2015-06-01

    Cd substituted Cobalt ferrite nano particles are synthesis using co-precipitation method. The as prepared samples are calcinated at 300 and 600 °C respectively. The existence of single phase spinal cubic structure of the prepared ferrite material is confirmed by the powder XRD measurement. The surface morphology images, compositional features are studied by SEM with EDX, and TEM. From the FT-IR spectra the absorption bands observed at 595 and 402 cm-1 are attributed to vibrations of tetrahedral and octahedral complexes respectively. From the VSM data, parameters like magnetization, coercivity, remanent magnetization and remanent squareness are measured. The saturation magnetization value is increases with increasing calcination temperature. The DSC and TG-DTA curves reveal that the thermal stability of the prepared ferrite nanoparticles. The calcination temperature affects the crystallite size, morphology and magnetic properties of the samples.

  17. Dielectric properties of cobalt ferrite nanoparticles in ultrathin nanocomposite films.

    PubMed

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

    2013-12-01

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

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

    PubMed

    Amiri, S; Shokrollahi, H

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  20. 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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

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

    E-print Network

    Paris-Sud XI, Université de

    1 Synthesis and microstructure of cobalt ferrite nanoparticles L.Ajroudi1,2 , S.Villain1 , V synthesized by a new non-aqueous synthesis method. The cobalt ferrites were characterized by X of exhaust gases [9], oxidation of toluene [10] or propane [11], gas sensing [12]. Nickel ferrites showed

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

    PubMed

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

    2011-06-01

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

  5. Preparation of monodisperse ferrite nanocrystals with tunable morphology and magnetic properties.

    PubMed

    Liang, Ruizheng; Tian, Rui; Liu, Zhihui; Yan, Dongpeng; Wei, Min

    2014-04-01

    The synthesis of monodisperse magnetic ferrite nanomaterials plays an important role in several scientific and technological areas. In this work, dibasic spinel MFe2O4 (M=Mg, Ni, Co, Fe, Mn) and polybasic spinel ferrite MCoFeO4 (M=Mg, Ni, Mn, MgNi) nanocrystals were prepared by the calcination of layered double hydroxide (LDH) precursors at 900?°C, which was confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images demonstrate that the as-obtained spinel ferrites present a single-crystalline nature with uniform particle size and good dispersibility. The composition, morphology, and particle size can be effectively tuned by changing the metal ratio, basicity, reaction time, and temperature of the LDH precursors. In addition, these spinel ferrites show high magnetic saturation values in the range 21.7-84.3?emu?g(-1), which maintain a higher level than the previously reported magnetic nanoparticles. Therefore, this work provides a facile approach for the design and fabrication of spinel ferrites with controllable nanostructure and improved magnetism, which could potentially be used in magnetic and biological fields, such as recording media, sensors, drug delivery, and intracellular imaging. PMID:24482379

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

    Microsoft Academic Search

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

    2012-01-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

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

    2014-08-01

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

  9. Structural, IR, and Magnetic Studies of Annealed Li-Ferrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Agami, W. R.; Ashmawy, M. A.; Sattar, A. A.

    2013-10-01

    Nanoparticles of spinel Li-ferrite, Li0.5Fe2.5O4, were prepared by sol-gel autocombustion technique and annealed at different temperatures (T a = 673, 873, and 1073 K), i.e., at relatively low annealing temperatures to control the crystallite size. The saturation magnetization (M s) increased, and the surface area decreased by increasing the crystallite size, while Curie temperature (T C) remained almost constant. The critical crystallite size (D s), 74 nm, which corresponds to a maximum value of coercivity was determined. Samples with crystallite sizes ? D s had low initial permeability ?i, while the other samples lying in the multidomain region showed very high ?i values indicating a reversible domain wall displacement mechanism. Hence, the crystallite size plays an important role in changing the physical and magnetic properties of Li-ferrite.

  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. Microwave synthesis and characterization of Co-ferrite nanoparticles.

    PubMed

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

    2004-09-01

    Stable CoFe(2)O(4) nanoparticles have been obtained by co-precipitation using a microwave heating system. Transmission electron microscopy images analysis shows an agglomeration of particles with an average size of about 5 nm, and X-ray diffraction reveals the presence of a pure ferrite nanocrystalline phase. X-ray photoelectron spectroscopy and thermal gravimetric analysis show the presence of organic matter in the range of about 16 wt%. The magnetic response in DC fields is typical for an assembly of single-domain particles. The measured saturation magnetization is slightly larger than the bulk value, probably due to the presence of small amounts of Co and Fe. AC magnetization data indicate the presence of magnetic interactions between the nanoparticles. PMID:15276045

  13. 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 decreased in comparison with surfactant- free prepared samples. All of the nickel ferrite nanoparticles were superparamagnetic at room temperature. Graphical abstract PMID:22462726

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

    Microsoft Academic Search

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

    2002-01-01

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

  15. 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.

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

    2014-09-08

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Strontium and nickel doped lanthanum ferrite (LaFeO3) 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 (?') 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.

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

    E-print Network

    Boolchand, Punit

    OH followed by dropwise addition of H2O2 18% solution at 65­70 °C. This process produced nanoparticles of iron structures. Progress has been made recently in spinel ferrite-based nanoparticles in the synthesis-based nanoparticles offer exciting possibilities for targeting neoplastic cells.9,10 In this paper we report synthesis

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

    SciTech Connect

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

    2014-05-07

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

    Microsoft Academic Search

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

    2010-01-01

    Magnetic silver-coated ferrite nanoparticles with 39.8% weight gain (relative to ferrite nanopowder coated by a silver layer)\\u000a were synthesized by electroless deposition of silver on ferrite nanopowder. The mechanism of the electroless deposition was\\u000a explored in terms of pretreatment, sensitization, activation, and the reduction of silver–ammonia complexes. Experiments showed\\u000a that the optimal deposition conditions were a temperature of 50°C, pH

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

    PubMed Central

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

    2013-01-01

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

  2. Structural and electrical properties of neodymium substituted cobalt ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  3. 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. [Kettering University, Flint, Michigan 48504 (United States); Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201 (United States); University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); University of Alabama, Birmingham, Alabama 35294 (United States); Department of ECECS, University of Cincinnati, Ohio 45221 (United States)

    2006-04-15

    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.

  4. 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

  5. A simple way to prepare bismuth nanoparticles

    Microsoft Academic Search

    Yanbao Zhao; Zhijun Zhang; Hongxin Dang

    2004-01-01

    In this paper, we report a simple method to prepare bismuth nanoparticles from bulk bismuth. Bismuth nanoparticles of near spherical shape have been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and other techniques. Bismuth nanoparticles have mean diameter of 40–50 nm and exhibit the same crystal structure as the bulk bismuth. The surface of bismuth nanoparticle has been

  6. Magnetic liposomes based on nickel ferrite nanoparticles for biomedical applications.

    PubMed

    Rodrigues, Ana Rita O; Gomes, I T; Almeida, Bernardo G; Araújo, J P; Castanheira, Elisabete M S; Coutinho, Paulo J G

    2015-07-21

    Nickel ferrite nanoparticles with superparamagnetic behavior at room temperature were synthesized using a coprecipitation method. These magnetic nanoparticles were either covered with a lipid bilayer, forming dry magnetic liposomes (DMLs), or entrapped in liposomes, originating aqueous magnetoliposomes (AMLs). A new and promising method for the synthesis of DMLs is described. The presence of the lipid bilayer in DMLs was confirmed by FRET (Förster Resonance Energy Transfer) measurements between the fluorescent-labeled lipids NBD-C12-HPC (NBD acting as a donor) included in the second lipid layer and rhodamine B-DOPE (acceptor) in the first lipid layer. An average donor-acceptor distance of 3 nm was estimated. Assays of the non-specific interactions of magnetoliposomes with biological membranes (modeled using giant unilamellar vesicles, GUVs) were performed. Membrane fusion between both aqueous and dry magnetoliposomes and GUVs was confirmed by FRET, which is an important result regarding applications of these systems both as hyperthermia agents and antitumor drug nanocarriers. PMID:26095537

  7. High-frequency electromagnetic properties of the manganese ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Zeng, Min; Liu, Jue; Yue, Ming; Yang, Haozhe; Dong, Hangrong; Tang, Wukui; Jiang, He; Liu, Xiaofang; Yu, Ronghai

    2015-05-01

    Manganese (MnFe2O4) nanoparticles are prepared via a facile solvothermal method. The electromagnetic properties are investigated in 1-18 GHz, indicating the MnFe2O4 nanoparticles are the promising materials to be applied as microwave absorbers. The wave absorbing mechanism can be attributed to the dielectric loss, magnetic loss, and the synergetic effect. The permittivity dispersion behavior is explained by Debye dipolar relation expression. The complex permeability is analyzed using Landau-Lifshitz-Gilbert equation. Natural resonance, exchange resonance, and eddy current loss arise at different frequencies.

  8. Preparation of transparent conductors ferroelectric memory materials and ferrites

    DOEpatents

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

    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.

  9. 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.

  10. The superspin glass transition in zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Kaman, O.; Ko?ínková, 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.

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

    SciTech Connect

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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  13. 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

  14. 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).

  15. Multiedge refinement of extended x-ray-absorption fine structure of manganese zinc ferrite nanoparticles

    Microsoft Academic Search

    S. Calvin; E. E. Carpenter; B. Ravel; V. G. Harris; S. A. Morrison

    2002-01-01

    The structure of nanoparticle manganese zinc ferrites synthesized by a reverse micellar method is determined by analysis of the extended x-ray-absorption fine structure in combination with other techniques. Both empirical and theoretical standards are employed; manganese, zinc, and iron edges are refined simultaneously. It is determined that samples synthesized under similar conditions sometimes exhibit a markedly different distribution of cations

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

    E-print Network

    Spinu, Leonard

    magnetocrystalline anisotropy José M. Vargas, Abhishek Srivastava, Amin Yourdkhani, Luis Zaldivar, Gabriel Caruntu et to the intrinsic chemical characteristics and magnetocrystalline anisotropy of the ferrite nanoparticles at finite temperatures J. Appl. Phys. 110, 103906 (2011) Magnetic anisotropy and coercivity of Fe3Se4

  17. 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.

  18. 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

    2013-01-01

    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

  19. 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

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

    PubMed

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

    2013-06-01

    In this paper, Mg0.5Zn0.5-Cu(x)Fe2O4 ferrites nanoparticles were synthesized by facile co-precipitation route and characterized in detail in terms of their structural, electrical and magnetic properties as a function of Cu concentration. The prepared samples have cubic spinel phase as confirmed by X-ray diffraction patterns. The decrease of the lattice constant and increase of X-ray density indicate the solubility of Cu ions in the spinel lattice. The AC conductivity measurements between 300 K and 773 K at different frequencies 1 KHz up to 1 MHz, showed two different behaviors as semiconductor-like at high temperature and frequency depending behavior associated with dispersion phenomena at low temperatures. The conduction mechanism in the system is influenced by Cu concentration and the dominant one is the hopping conduction mechanism. Dielectric measurements at the same conditions of temperatures and frequencies exhibited that the dielectric loss increases with increasing the temperature and decreasing the frequency indicating the semiconducting nature of the ferrite compounds. An anomalous behavior of the dielectric loss is observed in samples with high Cu content which explained in terms of resonance between frequency accompanied the electronic hopping and the frequency of the external electric field. The analysis of Mössbauer spectra revealed that copper free compound is super-paramagnetically relaxed in nature and zinc free compound demonstrates ferrimagnetic order. Moreover, hyperfine field spectrum shows the migration of Cu ions from octahedral to tetrahedral site in zinc free compound. PMID:23862448

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

    PubMed

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

    2013-10-22

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

  2. 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…

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

    NASA Astrophysics Data System (ADS)

    Thirupathi, G.; Singh, R.

    2015-06-01

    The Mn0.25Zn0.75Fe2O4 (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.

  4. Anatase TiO 2 nanolayer coating on strontium ferrite nanoparticles for magnetic photocatalyst

    Microsoft Academic Search

    Wuyou Fu; Haibin Yang; Lianxia Chang; Hari-Bala; Minghua Li; Guangtian Zou

    2006-01-01

    TiO2\\/SrFe12O19 composite nanoparticles with core-shell structure have been obtained. The core SrFe12O19 nanoparticles were synthesized by citrate precursor technique with Fe\\/Sr ratio of 10.8, and then the shell TiO2 nanocrystals were derived via sol–gel technology. The presence of a small amount of polyethyleneimine (PEI) on the surface of the strontium ferrite nanoparticles facilitates this coating process. The morphology, crystalline structure,

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

    E-print Network

    Volinsky, Alex A.

    nanoparticles to coat iron powder. The nanocrystalline iron powders, with an average particle diameter of 20 nm­Zn ferrites. Mn­Zn ferrite uniformly coated the surface of the powder particles, resulting in a reduced compared with the epoxy resin coated samples at 10 kHz. The effects of heat treatment temperature

  6. Magnetic properties of bio-synthesized zinc ferrite nanoparticles

    SciTech Connect

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

    2011-01-01

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

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

    Microsoft Academic Search

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

    2006-01-01

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

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

    SciTech Connect

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

    2014-05-07

    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.

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    In current research work, Co1-xNix/2Srx/2Fe2O4 (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.

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

    PubMed

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

    2014-04-01

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

  13. Mössbauer studies of La–Zn substitution effect in strontium ferrite nanoparticles

    Microsoft Academic Search

    Sang Won Lee; Sung Yong An; In-Bo Shim; Chul Sung Kim

    2005-01-01

    Many studies on cation substitution have been carried out in sintered magnets application, since intrinsic magnetic properties such as saturation magnetization depend on the cation configuration in the M-type hexagonal structure. La–Zn substituted Sr-ferrite nanoparticles were fabricated by a sol–gel method. Their magnetic and structural properties were characterized by using the XRD, VSM, TG\\/DTA, and Mössbauer spectroscopy. We focused on

  14. Conductivity of silver paste prepared from nanoparticles

    Microsoft Academic Search

    Dongseok Seo; Jongkook Lee

    2008-01-01

    Conductivity of silver pastes using nanoparticles was investigated with sintering temperatures. Nano-sized silver particles with 50–100nm in size were prepared by chemical reduction method. Silver pastes composed of nanoparticles (80wt%), Pb-free frit (1.0wt%) and organic vehicle (19wt%) were screen printed on alumina substrates and sintered at temperatures ranging from 250 to 450°C. As increasing the sintering temperatures, densification and grain

  15. Photochemical preparation of ZnO nanoparticles

    Microsoft Academic Search

    Tomáš Gbur; Václav ?uba; Viliam Mú?ka; Martin Nikl; Karel Knížek; Milan Pospíšil; Ivo Jakubec

    Preparation of zinc oxide nanoparticles from aqueous solutions containing zinc nitrate or formate using UV irradiation was\\u000a investigated. Analysis of solid phase formed during irradiation confirmed the presence of zinc oxide or zinc peroxide nanoparticles\\u000a ranging in size from 1 to 70 nm, depending on initial precursors. Annealing at temperatures 650–1000 °C results in forming\\u000a of rice-like zinc oxide particles, up to

  16. Method to prepare nanoparticles on porous mediums

    DOEpatents

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

    2010-08-10

    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.

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

    PubMed Central

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

    2015-01-01

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

  18. Controlled oxidation of FeCo magnetic nanoparticles to produce faceted FeCo/ferrite nanocomposites for rf heating applications

    E-print Network

    Laughlin, David E.

    Controlled oxidation of FeCo magnetic nanoparticles to produce faceted FeCo/ferrite nanocomposites for polydisperse FeCo magnetic nanoparticles MNPs synthesized using an induction plasma torch. X-ray diffraction to promote oxidation and XRD was used to follow the evolution of the FeCo core and the Fe3O4 and FeO oxide

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

    Microsoft Academic Search

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

    1997-01-01

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

  20. Structural, spectroscopic and magnetic study of nanocrystalline Ni–Zn ferrites

    Microsoft Academic Search

    P. Priyadharsini; A. Pradeep; P. Sambasiva Rao; G. Chandrasekaran

    2009-01-01

    A series of Ni–Zn ferrites is prepared in the form of nanoparticles using a novel combustion method. The novelty lies in the direct mixing of reactants, which yields more effective and pure final product of nano ferrites. The XRD (X-Ray Diffraction) patterns are analyzed for determining the structural parameters and for predicting the cation distribution in the ferrites. The XRD

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

    Microsoft Academic Search

    K. A. Hempel; D. Bonnenberg

    1993-01-01

    Ba and Sr ferrites are prepared by sol-gel technique with different Fe\\/Ba(Sr) ratios in the starting materials. Magnetization, coercive, and anisotropy field strength are determined depending on the heat treatment of the gel and the iron\\/barium(strontium) ratio in the starting material. A two-step heat treatment is used to prepare single-domain powders with high magnetization. These powders prepared by sol-gel technique

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  3. Multiporous ceria nanoparticles prepared by spray pyrolysis

    Microsoft Academic Search

    Shao-Ju Shih; Konstantin B. Borisenko; Li-Jr Liu; Chin-Yi Chen

    2010-01-01

    The morphology of ceria nanoparticles prepared by spray pyrolysis (SP) from cerium (III) acetate and cerium (III) nitrate\\u000a hydrate precursors were characterized by transmission electron microscopy. It was observed that using the nitrate as a precursor,\\u000a particles containing multiple pores in the core can be prepared preferentially as opposed to the acetate precursor, when particles\\u000a with predominantly a single pore

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  5. Magnetic and structural studies of nickel-substituted cobalt ferrite nanoparticles, synthesized by the sol-gel method

    NASA Astrophysics Data System (ADS)

    Mozaffari, M.; Amighian, J.; Darsheshdar, E.

    2014-01-01

    In this study Ni substituted cobalt ferrite nanoparticles (NixCo1-xFe2O4 where x=0.1, 0.3, 0.5, 0.7 and 0.9) were prepared by the sol-gel method. Phase identification of the samples was performed by the X-ray diffraction (XRD) method and the mean crystallite sizes of the samples were obtained using Scherrer's formula. The results show that a minimum calcining temperature of 500 °C is required to obtain single phase spinel structures for all the samples. It was observed that the lattice parameter of the samples decreases from 8.350 to 8.300 Å with increasing Ni content. Morphology of the samples was investigated by a field emission scanning electron microscope (FESEM). Also mean particle sizes of the samples were obtained from FESEM images and there no relation between particle size and Ni content was found. Magnetic measurements were carried out on the cold pressed samples and the results show that saturation magnetization decreases as x increases. Curie temperatures of the samples were determined and the results show that by increasing x values their Curie temperatures increase. This increase was explained based on the change in superexchange interactions between magnetic ions by substitution of Ni ions in Co ferrite. Also the coercive forces of the samples decreased with increasing x values which was explained by the changes in magnetocrystalline anisotropy.

  6. 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. PMID:25966046

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

    PubMed

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

    2012-05-01

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

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

    PubMed

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

    2009-05-01

    Mn ferrite (MnFe(2)O(4)) nanoparticles, having diameters from 4 to 50 nm, were synthesized using a modified co-precipitation technique in which mixed metal chloride solutions were added to different concentrations of boiling NaOH solutions to control particle growth rate. Thermomagnetization measurements indicated an increase in Néel temperature corresponding to increased particle growth rate and particle size. The Néel temperature is also found to increase inversely proportionally to the cation inversion parameter, delta, appearing in the formula (Mn(1-delta)Fe(delta))(tet)[Mn(delta)Fe(2-delta)](oct)O(4). These results contradict previously published reports of trends between Néel temperature and particle size, and demonstrate the dominance of cation inversion in determining the strength of superexchange interactions and subsequently Néel temperature in ferrite systems. The particle surface chemistry, structure, and magnetic spin configuration play secondary roles. PMID:19420627

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

    NASA Astrophysics Data System (ADS)

    Amiri, S.; Shokrollahi, H.

    2013-11-01

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

  10. 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.

  11. Productive encounter: molecularly imprinted nanoparticles prepared using magnetic templates.

    PubMed

    Berghaus, Melanie; Mohammadi, Reza; Sellergren, Börje

    2014-08-18

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  13. Sonochemical preparation of GaSb nanoparticles.

    PubMed

    Li, Hong-Liang; Zhu, Ying-Chun; Palchik, Oleg; Koltypin, Yuri; Gedanken, Aharon; Palchik, Valery; Slifkin, Michael; Weiss, Aryeh

    2002-02-25

    A room temperature sonochemical method for the preparation of GaSb nanoparticles using less hazardous Ga and antimony chloride (SbCl(3)) as the precursors has been described. The formation of GaSb has been confirmed by means of XRD, EDAX, and XPS characterization. TEM and SAED results show that the as-prepared solid consists of nanosized GaSb crystals with sizes in the range 20-30 nm. The photoacoustic spectrum result reveals that the GaSb nanoparticles have a direct band gap of about 1.21 eV. On the basis of the control experiments and the extreme conditions produced by ultrasound, an ultrasound-assisted in-situ reduction/combination mechanism has been proposed to explain the reaction. PMID:11849061

  14. Preparation and characterization of monodisperse Fe nanoparticles.

    SciTech Connect

    Majetich, Sara A. (Carnegie Mellon University, Pittsburgh, PA); Farrell, Dorothy (Carnegie Mellon University, Pittsburgh, PA); Wilcoxon, Jess Patrick

    2003-06-01

    Fe nanoparticles prepared by iron carbonyl decomposition using different methods are compared structurally, chemically, and magnetically. The specific magnetization of the particles was determined from the magnetic moment, the particle size observed by transmission electron microscopy, and the total iron concentration found from calibrated X-ray fluorescence. The volume fraction of oxide is reported for particles of different sizes and for particles made by slightly different techniques.

  15. 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

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  17. 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

  18. Curcumin nanoparticles: preparation, characterization, and antimicrobial study.

    PubMed

    Bhawana; Basniwal, Rupesh Kumar; Buttar, Harpreet Singh; Jain, V K; Jain, Nidhi

    2011-03-01

    Curcumin is a highly potent, nontoxic, bioactive agent found in turmeric and has been known for centuries as a household remedy to many ailments. The only disadvantage that it suffers is of low aqueous solubility and poor bioavailability. The aim of the present study was to develop a method for the preparation of nanoparticles of curcumin with a view to improve its aqueous-phase solubility and examine the effect on its antimicrobial properties. Nanoparticles of curcumin (nanocurcumin) were prepared by a process based on a wet-milling technique and were found to have a narrow particle size distribution in the range of 2-40 nm. Unlike curcumin, nanocurcumin was found to be freely dispersible in water in the absence of any surfactants. The chemical structure of nanocurcumin was the same as that of curcumin, and there was no modification during nanoparticle preparation. A minimum inhibitory concentration of nanocurcumin was determined for a variety of bacterial and fungal strains and was compared to that of curcumin. It was found that the aqueous dispersion of nanocurcumin was much more effective than curcumin against Staphylococcus aureus , Bacillus subtilis , Escherichia coli , Pseudomonas aeruginosa , Penicillium notatum , and Aspergillus niger . The results demonstrated that the water solubility and antimicrobial activity of curcumin markedly improved by particle size reduction up to the nano range. For the selected microorganisms, the activity of nanocurcumin was more pronounced against Gram-positive bacteria than Gram-negative bacteria. Furthermore, its antibacterial activity was much better than antifungal activity. The mechanism of antibacterial action of curcumin nanoparticles was investigated by transmission electron micrograph (TEM) analysis, which revealed that these particles entered inside the bacterial cell by completely breaking the cell wall, leading to cell death. PMID:21322563

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

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

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

  20. Method for preparing spherical ferrite beads and use thereof

    DOEpatents

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

    2002-01-01

    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.

  1. Studies on manganese substituted cobalt ferrite prepared by autocombustion route

    NASA Astrophysics Data System (ADS)

    Kolekar, Y.; Kambale, R.; Gupta, R.; Kahol, P.; Ghosh, K.

    2011-03-01

    Compositions of Co1.2-xMnxFe1.8O4 (0 = x = 0.4) were synthesized by autocombustion route keeping oxidizer to fuel ratio at 1. Structural and compositional characterizations of all the samples were performed by XRD, SEM and EDS. Magnetization measurements showed that the Ms increases form 106.5 emu/g for x = 0.0 to 138.5 emu/g for x = 0.2 and then decreases from x = 0.3 (124.71 emu/g for x = 0.3 and 97.78 emu/g for x =0.4), whereas the coercivity (Hc) decreases with manganese (Mn) substitution, except for x = 0.3. Room temperature dielectric properties such as relative dielectric permittivity (er), dielectric loss and ac conductivity, were studied as a function of frequency in the range from 20 Hz to 1 MHz. These studies indicates that the relative dielectric permittivity increasing (from er = 600 for x =0.0 to er = 2400 for x = 0.4) with the increase of Mn content in cobalt ferrite and also all samples show the usual dielectric dispersion which may be due to the Maxwell-Wagner-type of interfacial polarization. Dr. Y. D. Kolekar gratefully acknowledges the award of BOYSCAST fellowship by Department of Science and Technology, India. *On leave from Department of Physics, University of Pune, Pune- 411 007, India.

  2. Preparation and Structural Characterization of Nanocrystalline Zn-Cu-Cr Ferrites with gd Substitution

    NASA Astrophysics Data System (ADS)

    Jiang, Jing; Chen, Chaochao; Ai, Lunhong

    Nanocrystalline spinel Zn-Cu-Cr ferrites with Gd substitution were prepared by a rheological phase reaction method. By means of the Fourier transform infrared (FTIR) spectra, Raman spectra, and X-ray diffraction (XRD), the cubic spinel structure of samples had been confirmed. The magnetic parameters such as saturation magnetization, remanent magnetization and coercivity can be tailored by controlling the content of substituting Gd ions.

  3. Preparation and magnetic properties of high coercivity strontium ferrite micropowders obtained by extended wet milling

    Microsoft Academic Search

    C. Tanasoiu; P. Nicolau; C. Miclea

    1976-01-01

    Micropowders of strontium ferrite were obtained by extended wet milling (over 1500 h) of an ordinary SrFe12O19powder prepared by a chemical process from oxalates. The room temperature intrinsic coercive force of the micropowder drastically increased from about 300 Oe (as milled samples) to 6000 - 6500 Oe after removing the stresses and the defects, introduced by milling, by a suitable

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

    PubMed

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

    2008-05-15

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

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

    Microsoft Academic Search

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

    2005-01-01

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

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

    PubMed

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

    2012-09-01

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

  7. The preparation of magnetic nanoparticles for applications in biomedicine

    Microsoft Academic Search

    Pedro Tartaj; M ar ´ õa del Puerto Morales; Sabino Veintemillas-Verdaguer; Teresita González-Carreño; Carlos J Serna

    2003-01-01

    This review is focused on describing state-of-the-art synthetic routes for the preparation of magnetic nanoparticles useful for biomedical applications. In addition to this topic, we have also described in some detail some of the possible applications of magnetic nanoparticles in the field of biomedicine with special emphasis on showing the benefits of using nanoparticles. Finally, we have addressed some relevant

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

    NASA Astrophysics Data System (ADS)

    Kumar, E. Ranjith; Kamzin, Aleksandr S.

    2015-03-01

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

  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. PMID:25429495

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

    PubMed

    Zaki, H M; Al-Heniti, S

    2012-09-01

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

  11. Preparation of magnetic chitosan nanoparticles and immobilization of laccase

    Microsoft Academic Search

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

    2009-01-01

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

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

    PubMed

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

    2011-11-30

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

  13. 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. PMID:22962799

  14. Multiedge refinement of extended x-ray-absorption fine structure of manganese zinc ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Calvin, S.; Carpenter, E. E.; Ravel, B.; Harris, V. G.; Morrison, S. A.

    2002-12-01

    The structure of nanoparticle manganese zinc ferrites synthesized by a reverse micellar method is determined by analysis of the extended x-ray-absorption fine structure in combination with other techniques. Both empirical and theoretical standards are employed; manganese, zinc, and iron edges are refined simultaneously. It is determined that samples synthesized under similar conditions sometimes exhibit a markedly different distribution of cations between the available sites in the spinel structure; this in turn causes significant differences in the magnetic properties of the samples. In addition, it is found that the mean-square displacements for manganese-oxygen bonds are consistently higher than for zinc-oxygen bonds, perhaps due to the presence of manganese ions of more than one valence.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    Ferrite magnetic nanoparticles in the composition Zn0.7Ni0.3Fe2O4 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, Hres, linewidth, ?H, and peak ratio, R, for each magnetic phase. At low temperatures, the ferrimagnetic phase showed low Hres, broad ?H, and asymmetric R. At high temperatures, these parameters exhibited opposite values: high Hres, small ?H, 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 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.

  16. Simple one-step preparation of cerium trifluoride nanoparticles

    Microsoft Academic Search

    Vilém Bart?n?k; Jakub Rak; Vladimír Král; Olga Smr?ková

    2011-01-01

    Cerium trifluoride have great potential in material applications for luminescent materials, composite materials or ionic conductors especially in the form of nanoparticles and nanoobjects. In this work, nanoparticles of CeF3 were prepared by simple one pot reaction of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) with CeO2 and by reaction of CeO2 with KPF6 in ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl). Prepared nanoparticles

  17. Study of Ni-Zn Ferrite Prepared From Citrate Precursor

    NASA Astrophysics Data System (ADS)

    Sudheesh, V. D.; Vinesh, A.; Lakshmi, N.; Venugopalan, K.

    2011-07-01

    Ni0.5Zn0.5Fe2O4 prepared using citrate precursor method and calcined at different temperatures is studied using X-ray diffraction (XRD), Mössbauer spectroscopy and DC magnetization. Magnetization study shows that critical size of the sample is around 50 nm. Mössbauer studies confirm that there is no change in the cation distribution with calcining and also that a particle size distribution exists in samples calcined at higher temperatures. Thus the change in magnetic properties can be entirely attributed to structural parameters due to variation in size leading to different core-spin ratio, grain boundary effects etc.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  19. 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. PMID:21664499

  20. 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 ?g/ml and 2.5 ?g/ml. Further, this detection was ten times lower than previous reports and the detection limit of mouse IgG was 0.1 ?g/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. PMID:22063549

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

    PubMed

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

    2014-01-01

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

  2. 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??m-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

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

    PubMed

    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??m-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

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

    Microsoft Academic Search

    N. Burriesci; F. Garbassi; S. Pizzini

    1978-01-01

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

  5. Preparation of nickel and Ni-Zn ferrite films by thermal decomposition of metal acetylacetonates

    Microsoft Academic Search

    Hideaki Itoh; Tadashi Takeda; Shigeharu Naka

    1986-01-01

    Nickel and Ni-Zn ferrite (Ni1?x\\u000a Zn\\u000a x\\u000a Fe2O4) films were prepared on various substrates (quartz glass, MgO single crystal, etc.) by thermal decomposition of metal acetylacetonates\\u000a (Ni (acac)2 2H2O, Zn (acac)2 2H2O and Fe (acac)3). Typical decomposition and heat treatment conditions for obtaining a single phase of NiFe2O4 film were as follows: evaporation temperature of Ni-Fe complexes: 230C, the mole

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

    PubMed

    Yaseneva, Polina; Bowker, Michael; Hutchings, Graham

    2011-11-01

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

  7. Synthesis and coating of cobalt ferrite nanoparticles: a first step toward the obtainment of new magnetic nanocarriers.

    PubMed

    Baldi, Giovanni; Bonacchi, Daniele; Franchini, Mauro Comes; Gentili, Denis; Lorenzi, Giada; Ricci, Alfredo; Ravagli, Costanza

    2007-03-27

    Monodisperse and stable cobalt ferrite (CoFe2O4) nanoparticles (5.4 nm) have been produced, coated with mono- and difunctional phosphonic and hydroxamic acids, and fully characterized (using thermogravimetric analysis (TGA), dynamic light scattering (DLS), IR spectroscopy, transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) measurements). Cobalt leakage of the coated nanoparticles has been also studied. Magnetic measurements show the possible applications in hyperthermia at low frequencies, and for this reason, water-soluble coated CoFe2O4 can be seen as a first step toward the obtainment of novel systems for biomagnetic applications. PMID:17335257

  8. 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.

  9. Use of multiple-edge refinement of extended x-ray absorption fine structure to determine site occupancy in mixed ferrite nanoparticles

    Microsoft Academic Search

    S. Calvin; E. E. Carpenter; V. G. Harris; S. A. Morrison

    2002-01-01

    The site occupancy of manganese zinc ferrite (MZFO) nanoparticles is determined by a multiple-edge refinement of the extended x-ray absorption fine structure of the manganese, zinc, and iron absorption edges. The MZFO nanoparticles are generated by a reverse micellar synthetic route and compared to a ceramic standard. The simultaneous fitting of multiple absorption edges to a constrained model is found

  10. Tuning high aqueous phase uptake in nonionic water-in-oil microemulsions for the synthesis of Mn-Zn ferrite nanoparticles: phase behavior, characterization, and nanoparticle synthesis.

    PubMed

    Aubery, Carolina; Solans, Conxita; Sanchez-Dominguez, Margarita

    2011-12-01

    In this work, the formation of water-in-oil (w/o) microemulsions with high aqueous phase uptake in a nonionic surfactant system is investigated as potential media for the synthesis of Mn-Zn ferrite nanoparticles. A comprehensive study based on the phase behavior of systems containing precursor salts, on one hand, and precipitating agent, on the other hand, was carried out to identify key regions on (a) pseudoternary phase diagrams at constant temperature (50 °C), and (b) pseudobinary phase diagrams at constant surfactant (S):oil(O) weight ratio (S:O) as a function of temperature. The internal structure and dynamics of microemulsions were studied systematically by conductivity and self-diffusion coefficient determinations (FT PGSE (1)H NMR). It was found that nonpercolated w/o microemulsions could be obtained by appropriate tuning of composition variables and temperature, with aqueous phase concentrations as high as 36 wt % for precursor salts and 25 wt % for precipitating agent systems. Three compositions with three different dynamic behaviors (nonpercolated and percolated w/o, as well as bicontinuous microemulsions) were selected for the synthesis of Mn-Zn ferrites, resulting in nanoparticles with different characteristics. Spinel structure and superparamagnetic behavior were obtained. This study sets firm basis for a systematic study of Mn-Zn ferrite nanoparticle synthesis via different scenarios of microemulsion dynamics, which will contribute to a better understanding on the relationship of the characteristics of the obtained materials with the properties of the reaction media. PMID:22039992

  11. Nanoparticles: structure, properties, preparation and behaviour in environmental media

    Microsoft Academic Search

    P. Christian; F. Von der Kammer; M. Baalousha; Th. Hofmann

    2008-01-01

    There is increasing interest and need to develop a deeper understanding of the nature, fate and behaviour of nanoparticles\\u000a in the environment. This is driven by the increased use of engineered nanoparticles and the increased pressure to commercialise\\u000a this growing technology. In this review we discuss the key properties of nanoparticles and their preparation and then discuss\\u000a how these factors

  12. Magnetic properties and formation of Sr ferrite nanoparticle and Zn, Ti\\/Ir substituted phases

    Microsoft Academic Search

    Qingqing Fang; Yanmei Liu; Ping Yin; Xiaoguang Li

    2001-01-01

    Strontium hexaferrite nanoparticles are prepared by the chemical sol–gel route. Specific saturation magnetization ?s and coercive field strength Hc are determined depending on the heat treatment of the gel and iron\\/strontium ratio in the starting solution. These ultrafine powders with single-domain behavior have specific saturation magnetization ?s=74emu\\/g and coercive field strength Hc=6.4kOe. Experimental results show that it is necessary to

  13. 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 (?f) of Mo-Chl/dimethyl-sulphoxide (DMSO) was lower than 0.1, with a lifetime of 5.0 ns, as obtained from time-correlated single-photon counting technique. The oxygen quantum yield of Mo-Chl was carried out using laser flash-photolysis studies in homogeneous medium saturated with O2(g) (?? = 0.50). Cellular viability was also evaluated via the classical MTT assay using gingival fibroblasts cells as a biological model. Studies performed with the complex Mo-Chl (5.0 ?mol.L-1)/MF at different magnetic nanoparticle concentrations (ranging from 1012 to 1015 particle.mL-1) revealed a cellular viability of approximately 95% for the ideal magnetic material concentration of 1×10 particle.mL-1. The present study shows that natural photosensitizers molecules Mo-Chl used in association with magnetic nanoparticles represent a promising generation of drug developed to work synergistically in the treatment of neoplastic tissues using PDT and HPT.

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

    Microsoft Academic Search

    Tal Meron; Yuri Rosenberg; Yossi Lereah; Gil Markovich

    2005-01-01

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

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

    PubMed

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

    2012-08-01

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

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

    Microsoft Academic Search

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

    2010-01-01

    In this work, gold nanoparticles with three different sizes (13.7, 39.4, and 76.7 nm) were prepared using a simple aqueous\\u000a method with gallic acid as the reducing and stabilizing agent, the different sizes were obtained varying some experimental\\u000a parameters as the pH of the reaction and the amount of the gallic acid. The prepared nanoparticles were characterized using\\u000a X-ray diffraction, transmission

  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 thickness increasing from about 20 to 120 nm while shifting from 3 to 10 CoFe(2)O(4)/PSS bilayers, using the 8.9 × 10(-6) (moles of cobalt ferrite per litre) suspension. PMID:22025281

  18. Magnetic Nanoparticle Arrays prepared via Coaxial Electrospinning

    Microsoft Academic Search

    Nikhil Sharma; Hassnain Jaffari; Ismat Shah; Darrin Pochan

    2009-01-01

    One dimensional nanoparticle (1D NP) arrays display strong anisotropy in their physical properties making them interesting from a fundamental as well as applications perspective. 1D arrays of Fe3O4 nanoparticles have been constructed by encapsulating magnetite nanoparticles within Poly(ethylene oxide) nanofibers, by a modified solution spinning process. Electrospinning is a facile process for creating 1D nanostructures and a simple modification to

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

    Microsoft Academic Search

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

    2007-01-01

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

  20. Magnetic studies of Li-Zn ferrites prepared by citrate precursor method

    NASA Astrophysics Data System (ADS)

    Soibam, Ibetombi; Phanjoubam, Sumitra; Sharma, H. B.; Sarma, H. N. K.; Prakash, C.

    2009-11-01

    Ferrites having the general formula Li 0.5-0.5xZn xFe 2.5-0.5xO 4 where 0? x?0.6 in steps of 0.2 were prepared by the citrate precursor method. The Curie temperature measured shows a decrease with increasing Zn concentration. Experimental results show that the room temperature initial permeability increases with the increase in the concentration of zinc. The initial permeability has also been studied as a function of frequency in the range of 100 Hz-1 MHz. The real part of initial permeability referred as initial permeability and the imaginary part of initial permeability better known as permeability loss show dispersion with frequency. Possible mechanism contributing to the above processes is discussed.

  1. Hybrid polymer/nanoparticle solar cells: preparation, principles and challenges.

    PubMed

    Saunders, Brian R

    2012-03-01

    Hybrid polymer/nanoparticle solar cells have a light harvesting layer composed of semiconducting inorganic nanoparticles and a semiconducting conjugated polymer. They have potential to give high power conversion efficiencies (PCE). However, the PCE values reported for these solar cells are not currently as high as anticipated. This article reviews the main methods currently used for preparing hybrid polymer/nanoparticle solar cells from the colloid perspective. PCE data for the period of 2005-2011 are presented for hybrid polymer/nanoparticle solar cells and compared to those from polymer/fullerene cells. The key reasons for the relatively low PCE values for hybrid polymer/nanoparticle solar cells are uncontrolled aggregation and residual insulating ligands at the nanoparticle surface. Two hybrid polymer/nanoparticle systems studied at Manchester are considered in which the onset of aggregation and its affect on composite film morphology were studied from the colloidal perspective. It is concluded that step-change approaches are required to increase the PCEs of hybrid polymer/nanoparticle solar cells and move them toward the 10% value required for widespread commercialisation. A range of nanoparticles that have potential for application in possible longer term terawatt solar energy production are discussed. PMID:22209577

  2. 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....

  3. Preparation of nanoparticles with an environment-friendly approach.

    PubMed

    Yao, Kefu; Peng, Zhen; Fan, Xiaolin

    2009-01-01

    Developing various approaches for preparing high performance materials has long been topics and tasks both for scientists and for engineers. Despite that many methods have been developed for preparing nanomaterials, developing simple and environment-friendly ways for preparing nanomaterials is very attractive. Here a simple approach of synthesizing Fe3O4 nanoparticles by arc-discharge submerging in water was reported. The results showed that by this method Fe3O4 nanoparticles can be synthesized at large scale. The as-prepared Fe3O4 nanoparticles exhibited uniform spherical shape and their diameters varied with arc-discharging parameters. The experimental results showed that the size of the synthesized Fe3O4 nanoparticles can be controlled through adjusting the processing parameters. Since no vacuum system has been used, the synthesizing process is greatly simplified. In addition, only cheap deionized water and industrial iron bar are used and no pollution or harmful byproducts are found in the synthesis process. It indicated that the present approach is a simple, low-cost and environment-friendly one for preparing nanoparticles. PMID:19803073

  4. Preparation of magnetic fluorescent hollow nanoparticles with multi-layer

    NASA Astrophysics Data System (ADS)

    Sun, Xiuxue; Zhang, Jimei; Dai, Zhao; Li, Ping; Zhou, Wen; Zheng, Guo

    2009-07-01

    A kind of novel magnetic fluorescent hollow nanoparticles with multi-layer shells by layer-by-layer self-assembly process was presented in this paper. Non-crosslinking poly(acrylic acid) (PAA) nanoparticles as core with 250 nm in diameters were prepared by distillation-precipitation polymerization in acetonitrile with 2, 2'-Azobisisobutyronitrile (AIBN) as initiator and without any stabilizer and crosslinker. Then 4-vinylpyridine (4-VPy) as monomer was selfassembled on the surface of PAA nanoparticles because of hydrogen-bonding effect between the surface carboxyl of PAA nanoparticles and pyridine of 4-VPy. The 4-VPy as first shell layer were crosslinked by ethylene glycol dimethacrylate (EGDMA) by seeds distillation-precipitation polymerization in acetonitrile. The core/shell structure of this kind of nanoparticles was investigated by FT-IR and TEM. We can find that the products had an absorption peak at 1641 cm-1 from the FT-IR, which showed that the vinyl groups had been connected in the polyAA microspheres. After that, the non-crosslinking PAA core was removed under a solution of sodium hydroxide in ethanol-water. On the other hand, CdTe quantum dots (QDs) with about 3 nm in diameters as shell were prepared in aqueous solution with 3- mercaptopropionic acid (MPA) as stabilizer and 1, 6-hexylenediamime modified Fe3O4 nanoparticles with about 11 nm in diameters as core were synthesized in water respectively. Because of the hydrogen-bonding between the surface carboxyl of MPA on CdTe QDs and the amino on Fe3O4 nanoparticles, the core/shell magnetic-fluorescent nanoparticles were obtained. Then, the magnetic-fluorescent nanoparticles as second shell layer were self-assembled on the hollow 4VPy nanoparticles.

  5. Preparation of size-controlled nanoparticles of magnetite

    NASA Astrophysics Data System (ADS)

    Andrade, Ângela L.; Valente, Manuel A.; Ferreira, José M. F.; Fabris, José D.

    2012-05-01

    Samples of ferrofluids containing chemically stabilized nanoparticles of magnetite (Fe3O4) with tetramethylammonium hydroxide (TMAOH) were prepared by a direct reduction-precipitation method. The influences of aging time and temperature on the size and monodispersion characteristics of the produced nanoparticles were investigated. Transmission electron microscopy, powder X-ray diffraction, Fourier-transform infrared, and magnetization measurements with applied magnetic field up to 2 T were used to characterize the synthesized iron oxides. Raising the temperature of the synthesized material in autoclave affects positively the monodispersion of the nanoparticles, but it was not found to significantly influence the size itself of individual particles.

  6. Preparation and physicochemical characterization of naproxen-PLGA nanoparticles.

    PubMed

    Javadzadeh, Yousef; Ahadi, Fatemeh; Davaran, Soodabeh; Mohammadi, Ghobad; Sabzevari, Araz; Adibkia, Khosro

    2010-12-01

    Naproxen is a non-steroidal anti-inflammatory drug which can be used for the treatment of inflammatory disorders like uveitis and arthirit rheumatoid. The aim of the present study was to investigate the physicochemical characteristics of naproxen-PLGA nanoparticles. The nanoparticles of naproxen with PLGA were formulated using the solvent evaporation/extraction technique (the single emulsion technique). Several process parameters i.e., drug/polymer ratio, aqueous phase volume and speed of homogenization were considered with the aim of achieve optimal preparation conditions. The physicochemical characteristics of nanoparticles were studied applying particle size analysis, differential scanning calorimetry, X-ray crystallography, Fourier transform infrared spectroscopy and scanning electron microscopy. The release rate of naproxen from various drug/polymer nanoparticles was investigated as well. All the prepared formulations using PLGA resulted in nano-range size particles (352-571 nm) with spherical smooth morphology. The nanoparticles of naproxen-PLGA displayed lower crystallinity with no chemical interactions between the drug and polymer molecules. The nanoparticles exhibited the slower release of drug in comparison with the intact drug and the physical mixtures. According of these findings, formulation of the naproxen-PLGA nanoparticles was able to improve the physicochemical characteristics of the drug and possibly will increase the anti-inflammatory effects of drug following its ocular or intra-joint administration. PMID:20719477

  7. 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, E-mail: merey_anwar@yahoo.com [Thermal Transport Laboratory, Materials Engineering Department, School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology, H-12, Islamabad (Pakistan); Maqsood, Asghari [Centre for Emerging Sciences, Engineering and Technology (CESET), I-10/3, Islamabad (Pakistan)

    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 (??) 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.

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

    2009-02-04

    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.

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

    PubMed

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

    2012-06-15

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

  10. Preparation of Alumina Nanoparticles by Pulsed Wire Discharge in Water

    NASA Astrophysics Data System (ADS)

    Tokoi, Y.; Izuari, Y. M.; Suzuki, T.; Nakayama, T.; Suematsu, H.; Niihara, K.

    2011-10-01

    Alumina nanoparticles were prepared by pulsed wire discharge (PWD) using aluminium wire in deionized water at relative energy of 2, which is the ratio of the charged energy of the capacitor and the vaporization energy of the wire. From voltage and current waveforms during PWD, calculated deposited energy of the wire was larger than the vaporization energy of the wire. Scanning electron microscopy images showed that the prepared Al2O3 nanoparticles were spherical particles with the median particle diameter of 103 nm and the geometric standard deviation of 2.3. The X-ray diffraction analyses indicated that the prepared nanoparticles were identified as ?-Al2O3. From these results, pure ?-Al2O3 with particle size of around 100 nm was successfully synthesized by PWD in water.

  11. Use of multiple-edge refinement of extended x-ray absorption fine structure to determine site occupancy in mixed ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Calvin, S.; Carpenter, E. E.; Harris, V. G.; Morrison, S. A.

    2002-11-01

    The site occupancy of manganese zinc ferrite (MZFO) nanoparticles is determined by a multiple-edge refinement of the extended x-ray absorption fine structure of the manganese, zinc, and iron absorption edges. The MZFO nanoparticles are generated by a reverse micellar synthetic route and compared to a ceramic standard. The simultaneous fitting of multiple absorption edges to a constrained model is found to yield site occupancies accurate to within eight percentage points.

  12. Preparation of candesartan and atorvastatin nanoparticles by solvent evaporation.

    PubMed

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

    2012-01-01

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

  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. Photocatalytic Activity of Highly Porous Zinc Ferrite Prepared from a Zinc-Iron(III)Sulfate Layered Double Hydroxide Precursor

    Microsoft Academic Search

    Weiqing Meng; Feng Li; David G. Evans; Xue Duan

    2004-01-01

    A zinc-iron(III)-sulfate layered double hydroxide (LDH) has been prepared from zinc and iron(II) precursors. Calcination at 500°C or above affords a mixture of ZnO (zincite) and ZnFe2O4 (spinel) phases. Treatment of the calcined products with aqueous NaOH leads to dissolution of the ZnO and the formation of a pure zinc ferrite phase with high surface area and pore volume. When

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

    Microsoft Academic Search

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

    2005-01-01

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

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

    PubMed

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

    2015-03-28

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

  17. Preparation of micro and nanoparticles from corn cobs xylan

    Microsoft Academic Search

    Rosângela B. Garcia; Toshiyuki Nagashima Jr; Ana K. C. Praxedes; Fernanda N. Raffin; Túlio F. A. L. Moura; E. Sócrates T. do Egito

    2001-01-01

    Summary  \\u000a Xylan, a hemicelllulose extracted from corn cobs, was used to prepare micro and nanoparticles. First, a chemical evaluation\\u000a of xylan extract was performed. Then, particles were prepared by a coacervation method based on neutralization of an alkaline\\u000a solution with an acid solution. The influence of polymer content (2.85 to 100 mg\\/ml) and surfactant presence (0.6 to 1.8%(v\\/v)) on the

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

    SciTech Connect

    Kahn, Myrtil L.; Zhang, Z. John

    2001-06-04

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

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

    SciTech Connect

    Buršík, J., E-mail: bursik@iic.cas.cz [Institute of Inorganic Chemistry of the AS CR, v.v.i., 250 68 Husinec-?ež 1001 (Czech Republic); Kužel, R. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 5, 121 16 Praha 2 (Czech Republic); Knížek, K.; Drbohlav, I. [Institute of Physics of the AS CR, v.v.i., Na Slovance 2, 182 21 Praha 8 (Czech Republic)

    2013-07-15

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

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

    PubMed

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

    2011-07-29

    The synthesis and properties of Mg((x))Zn((1 - x))Fe(2)O(4) spinel ferrites as a low-toxicity alternative to the technologically significant Ni((x))Zn((1 - x))Fe(2)O(4) ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe(2)O(4) were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ? 80-120 nm) with an average diameter of the order of 100 nm ± 20 nm and could be produced in high process yields of up to 25 g l(-1). In contrast, particles synthesised by the polyol-based co-precipitation method possess a narrower size distribution with an average diameter in the 30 nm ± 5 nm range but are limited to smaller yields of ? 6 g l(-1). Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties. PMID:21719975

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

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

    Microsoft Academic Search

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

    2002-01-01

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

  3. Preparation and evaluation of carboplatin biodegradable polymeric nanoparticles.

    PubMed

    Nanjwade, Basavaraj K; Singh, Jeet; Parikh, Kemy A; Manvi, F V

    2010-01-29

    The present study was designed to evaluate targeting efficiency of carboplatin anticancer drug. Drug was encapsulated in natural biodegradable polymer sodium alginate. The nanoparticles were prepared by the ion gelification technique and evaluated for encapsulation efficiency, loading capacity, in vitro release pattern and targeting efficiency. Drug encapsulation efficiency was about 52.24-68.70% for different formulations. In vitro release profile showed duration of drug release was also increased (more than 12 h) by nanoparticulate formulation as compared to pure drug (up to 3 h). The formulations were parenterally administered to laca mice and the drug was detected in body organs like liver, lungs and spleen. In case of free drug, less amount of drug was found in liver, lungs and spleen as compared to drug encapsulated nanoparticles. Thus sodium alginate nanoparticles can be used for targeting carboplatin and it can be a promising tool in the delivery of anticancer drugs. PMID:19854254

  4. Synthesis and characterization of carbon nanotubes decorated with strontium ferrite nanoparticles

    Microsoft Academic Search

    De-xu Zhao; Qiao-ling Li; Yun Ye; Cun-rui Zhang

    2010-01-01

    A uniform coated compound material was obtained by the in situ sol–gel reaction among modified carbon nanotubes, nitric acid strontium, and nitric acid iron. The results indicated that the carbon nanotubes were coated with M-type magnetoplumbite ferrite, and its size was at the nanometer level. Along with the increase in the content of carbon nanotubes, the tubular structures of the

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

    PubMed Central

    Bregar, Vladimir B; Lojk, Jasna; Šuštar, Vid; Verani?, 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

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

    PubMed

    Bregar, Vladimir B; Lojk, Jasna; Suštar, Vid; Verani?, 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

  7. 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.

  8. Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  9. Optimization of the preparation process for human serum albumin (HSA) nanoparticles

    Microsoft Academic Search

    K. Langer; S. Balthasar; V. Vogel; N. Dinauer; H. von Briesen; D. Schubert

    2003-01-01

    Nanoparticles prepared by desolvation and subsequent crosslinking of human serum albumin (HSA) represent promising carriers for drug delivery. Particle size is a crucial parameter, in particular for the in vivo behaviour of nanoparticles after intravenous injection. The objective of the present study is the development of a desolvation procedure for the preparation of HSA-based nanoparticles under the aspect of a

  10. Retsch PM400 ball mill Nanoparticle preparation

    E-print Network

    Anderson, Scott L.

    immediately formed oxide upon exposure to air as the XPS samples were prepared. · Oleic acid prevented + Solvent (Ethanol) 18 hrs milling Samples washed with EtOH to remove excess surfactant 4 x 250 ml capacity 20 35 63 113 203 365 655 0 0.5 1 11 20 35 63 113 203 365 655 86 nm (57%) 189 nm (43%) 81 nm (93%) 178

  11. 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

  12. Preparation of Nanoparticles of Thermoelectric Materials by Ultrasonic Milling

    NASA Astrophysics Data System (ADS)

    Marquez-Garcia, L.; Li, Wei; Bomphrey, J. J.; Jarvis, D. J.; Min, Gao

    2015-06-01

    The ability to produce nanoscale thermoelectric powders is particularly relevant to the development of nanostructured bulk materials. In this paper we report preparation of nanoscale thermoelectric powders by high-intensity ultrasonic milling (UM). The particles obtained have two unique features: the presence of a particle-size gap which distinguishes the newly created nanoparticles from the original particles, and significant changes of the surface morphology of the particles, suggesting potential manipulation of the surface states of micro or nano particles.

  13. Cerium oxide nanoparticles prepared in self-assembled systems

    Microsoft Academic Search

    Ali Bumajdad; Julian Eastoe; Asha Mathew

    2009-01-01

    This review concerns recent research on the synthesis of cerium oxide (also known as ceria, CeO2) in colloidal dispersions media for obtaining high surface area catalyst materials. Nanoparticles as small as 5 nm and surface area as high as 250 m2\\/g can be readily prepared by this method. Both normal micelles and water-in-oil microemulsions have been employed to directly precipitate nanoceria or

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

    NASA Astrophysics Data System (ADS)

    Pervaiz, Erum; Gul, I. H.

    2012-11-01

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

  15. 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

  16. Ultrasonic Nozzle Spray in Situ Mixing and Microwave-Assisted Preparation of Nanocrystalline Spinel Metal Oxides: Nickel Ferrite and Zinc Aluminate

    Microsoft Academic Search

    Edward K. Nyutu; William C. Conner; Scott M. Auerbach; Chun-Hu Chen; Steven L. Suib

    2008-01-01

    Nanocrystalline spinel nickel ferrite and zinc aluminate particles (6 -20 nm) can be prepared by a recently developed continuous flow method that combines microwave heating and in situ ultrasonic nozzle spray mixing. The preparations were carried out at ambient pressure (1 atm), microwave power (0-600 W), and ultrasonic nozzle with resonant frequency of 48 or 120 kHz. The products were

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

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

    PubMed

    Denadai, Angelo 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; Sinisterra, Rubén D

    2012-01-01

    Organic-inorganic magnetic hybrid materials (MHMs) combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with ?-cyclodextrin (Fe-Ni/Zn/?CD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr(3+) and Cr(2)O(7) (2-) ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/?CD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer-Emmett-Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of ?CD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with ?CD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/?CD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn. PMID:23209524

  20. Preparation and tribological properties of a kind of lubricant containing calcium borate nanoparticles as additives

    Microsoft Academic Search

    Lifeng Hao; Jiusheng Li; Xiaohong Xu; Tianhui Ren

    2012-01-01

    Purpose – Nanoparticles are not well dispersed in non-polar organic solvents due to their hydrophilic property which limits their applications in lubricant oils. To improve the oil-solubility of nanoparticles, a novel technology was used to prepare a kind of lubricant containing calcium borate nanoparticles. Design\\/methodology\\/approach – The microstructures of the prepared nanoparticles were characterized by transmission electron microscope (TEM) and

  1. Size control and magnetic properties of single layer monodisperse Ni nanoparticles prepared by magnetron sputtering

    Microsoft Academic Search

    Tangchao Peng; Xiangheng Xiao; Wei Wu; Lixia Fan; Xiaodong Zhou; Feng Ren; Changzhong Jiang

    Single layer monodisperse Ni nanoparticles were successfully prepared by reductive annealing of NiO films formed by magnetron\\u000a sputtering. The spherical Ni nanoparticles had a monodisperse distribution on the substrate. The formation process of Ni nanoparticles\\u000a was investigated, and the Ni nanoparticle size can be precisely controlled by the magnetron sputtering time. Morphology of\\u000a these nanoparticles was observed with scanning electron

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

    SciTech Connect

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

    2010-02-15

    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, characterization, and surface modification of silver nanoparticles in formamide.

    PubMed

    Sarkar, Anjana; Kapoor, Sudhir; Mukherjee, Tulsi

    2005-04-28

    The reduction of silver ions in formamide is shown to take place spontaneously at room temperature without addition of any reductant. The growth of Ag particles was found to be dependent on Ag+ ion concentration. In the absence of any stabilizer, deposition of silver film on the glass walls of the container takes place. However, in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) or colloidal silica (SiO2), which are capable of stabilizing silver nanoparticles by complexing and providing support, a clear dispersion was obtained. The formation of the silver nanoparticles under different conditions was investigated through UV-visible absorption spectrophotometry, gas chromatography, and also electron and atomic force microscopic techniques. Atomic force microscopy results for silver films prepared in the absence of any stabilizer showed the formation of polygonal particles with sizes around 100 nm. Transmission electron microscopy results showed that the prepared silver particles in the presence of PVP were around 20 nm. The Ag nanoparticles get oxidized in the presence of chloroform and toluene. Surface modification of silver film was done in the presence of the tetrasodium salt of ethylenediaminetetraaceticacid (Na4EDTA). It was shown that the reactivity of the silver film increased in its presence. The Fermi potential of silver particles in the presence of Na4EDTA seems to lie between -0.33 and -0.446 V vs NHE. PMID:16851894

  4. Preparation of poly(?-lactide-co-glycolide) nanoparticles by modified spontaneous emulsification solvent diffusion method

    Microsoft Academic Search

    Hideki Murakami; Masao Kobayashi; Hirofumi Takeuchi; Yoshiaki Kawashima

    1999-01-01

    Purpose: The objectives of this study were to establish a new preparation method for poly(DL-lactide-co-glycolide) (PLGA) nanoparticles by modifying the spontaneous emulsification solvent diffusion (SESD) method and to elucidate the mechanism of nanoparticle formation on the basis of the phase separation principle of PLGA and poly(vinyl alcohol) (PVA) in the preparation system. Methods: PLGA nanoparticles were prepared by the modified-SESD

  5. Preparation and characterization of nebivolol nanoparticles using Eudragit® RS100.

    PubMed

    Jana, Utpal; Mohanty, Anjan Kumar; Manna, Prabal Kumar; Mohanta, Guru Prasad

    2014-01-01

    Nebivolol, a beta-blocker, has been widely used for the treatment of hypertension and cardiovascular diseases; but has drawbacks like poor solubility and bioavailability requiring frequent dosing. The present study attempts to overcome these issues through nanoparticulate delivery system using widely used carrier Eudragit(®) RS100. The solvent evaporation (single emulsion) technique was used for developing nanoparticles. The impact of formulation and process variables on particle size and entrapment efficiency was studied to optimize the formulation. The physico-chemical characterization confirmed the particle size in nano range with smooth and spherical morphology. Further, Fourier transforms infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) studies confirm compatibility of drug-polymer combination. The in vitro drug release study of the prepared nanoparticles showed prolongation of drug release with reduced burst release in comparison with pure drug powder. PMID:24140793

  6. Preparation and Properties of FeCo Nanoparticles

    SciTech Connect

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

    2010-07-13

    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.

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

    PubMed

    Singh, Charanjit; Goyal, Ankita; Singhal, Sonal

    2014-07-21

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

  8. Preparation and Electromagnetic Properties of Composites of Hollow Glass Microspheres Coated with NiFe2O4 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhao, Hai-tao; Ma, Rui-ting; Zhang, Gang; Xiao, Xuan

    2007-12-01

    The composites of hollow glass microspheres coated with NiFe2O4 nanoparticles were prepared using poly-acrylamide gel method. The structural characteristics, morphology and electromagnetic properties of the composite powders with different weight percent of glass microspheres (15%, 40%, and 65%) were obtained by X-ray diffraction, scanning electron microscope, infrared spectroscopy and HP8510 network analyzer. The results indicated that the phase structure of composite powders was the mixtures of nickel ferrite, quartz, and mullite. The peak intensity for nickel ferrite decreased rapidly and for mullite increased remarkably with the increasing amount of microspheres. A pure spinel structure of NiFe2O4 formed on the glass microspheres at 600°C. A uniform and continuous NiFe2O4-coating was obtained when the content of microspheres was 40%. A great amount of NiFe2O4 particle size is less than 80 nm. The composite with a content of 40% microspheres exhibits better dielectric and magnetic loss properties which are useful to absorb more electromagnetic wave. It can be a kind of good and light electromagnetic wave absorbing material in the X-band.

  9. Magnetic properties of MnZn ferrites prepared by soft chemical routes

    NASA Astrophysics Data System (ADS)

    Razzitte, A. C.; Jacobo, S. E.; Fano, W. G.

    2000-05-01

    MnZn ferrites with different composition have been synthesized by soft chemistry routes using oxalate precursors with the partial replacement of water by acetone as the solvent. Toroids were sintered at 1250 °C for 3 h in O2/N2 atmosphere. Sintering conditions significantly changed macroscopic characteristics as density and initial permeability for different composition. Variation of the complex permeability with frequency have been measured over a wide range of frequency, up to 1.8 GHz where dispersion is attributed to spin resonance. No additives for increasing densification were employed. Samples exhibit the highest permeability values for Mn0.8Zn0.2Fe2O4. An anomalous effect is observed when copper is added to MnZn ferrites. The initial permeability (?i) values do not exhibit much variation with temperature, except near Tc where it falls sharply. Curie point and magnetic losses are related with composition.

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

    Microsoft Academic Search

    I. H. Gul; A. Maqsood

    2008-01-01

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

  11. Preparation, complex permittivity and permeability of the electroless Ni–P deposited strontium ferrite powder

    Microsoft Academic Search

    Xifeng Pan; Haigen Shen; Jianxun Qiu; Mingyuan Gu

    2007-01-01

    Nanosized strontium ferrite powder was deposited with Ni–P by electroless plating under the agitation of ultrasonic wave at room temperature. The morphology, crystal structure, complex permittivity and complex permeability of the composite powder were investigated with field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive analysis of X-rays (EDS) and vector network analyzer. The results show that the

  12. Selectively Assembled Co Nanoparticle Stripes Prepared by Covalent Linkage and Microcontact Printing

    E-print Network

    Kim, Sehun

    force or van der Waals interaction. The assembly of monolayers of transition metal nanoparticles (e.gSelectively Assembled Co Nanoparticle Stripes Prepared by Covalent Linkage and Microcontact introduce a novel strategy to fabricate a bifunctional monolayer assembly of Co nanoparticles on a Si- (111

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

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

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

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

    Microsoft Academic Search

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

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

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

    PubMed

    Shi, Wenbing; Wang, Hui; Huang, Yuming

    2011-01-01

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

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

    Yu, Byong Yong; Kwak, Seung-Yeop

    2011-10-21

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

  18. Silver confined within zeolite EMT nanoparticles: preparation and antibacterial properties

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  19. Study on magnetic properties and structural analysis of Ni–Zn ferrite prepared through self-propagating high-temperature synthesis reaction by neutron diffractometry

    Microsoft Academic Search

    Yong Choi; H. S. Shim; J. S. Lee

    2001-01-01

    The NixZn1?xFe2O4 ferrites were prepared by self-propagating high-temperature synthesis at the oxygen partial pressures of 0.5 and 5.0 MPa. Neutron diffraction revealed that the final stoichiometries of the ferrites were Ni0.38Zn0.62Fe2O4 and Ni0.33Zn0.67Fe2O4, respectively. As the oxygen pressure changed from 0.5 to 5.0 MPa, the coercive force (Hc) and residual magnetization (Mr) decreased about 55 and 30%, respectively. Whereas, the

  20. Preparation of Polymer-Coated Functionalized Ferrimagnetic Iron Oxide Nanoparticles*

    E-print Network

    Yu, Shi

    A simple chemical method to synthesize PMAA coated maghemite nanoparticles is described. Monomer methacrylic acid molecules were absorbed onto the synthesized ferrimagnetic nanoparticles followed by polymerization. The ...

  1. Effect of light on the magnetic properties of cobalt ferrite nanoparticles

    Microsoft Academic Search

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

    2000-01-01

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

  2. Chain length dependence of polyol synthesis of zinc ferrite nanoparticles: why is diethylene glycol so different?

    PubMed

    Rishikeshi, Supriya N; Joshi, Satyawati S; Temgire, Mayur K; Bellare, Jayesh R

    2013-04-21

    Superparamagnetic ZnFe2O4 nanoparticles with size range of 28-38 nm were synthesized by polyol process based on use of varying chain length glycols as solvent. We have offered, for the first time, the plausible mechanism behind in situ formation of zinc ferric oxalate hydroxide hydrate [Fe2Zn(C2O4)2(OH)3](+)·4H2O complex from diethylene and polyethylene glycol. We are also reporting, the magnetic properties of above complexes. We have found a ferromagnetic ordering in precursor complex compounds. The intermediate hydrocarbon chain between the oxalato bridged metal cations plays a crucial role in obtaining anomalous magnetic behavior. ZnFe2O4 nanoparticles obtained after annealing the DEGylated precursor complex (precursor complex formed in diethylene glycol) showed the highest superparamagnetic (SPM) behavior (22.4 emu g(-1)) among others. The reasons for anomalous SPM behavior of ZnFe2O4 nanoparticles are explained on the basis of the degree of inversion of the spinel structure, high surface-to-volume ratio, which causes non-collinear spin arrangement in a surface layer and higher oxygen concentration on the surface of dead organic layer, which increases the unpaired valence electrons leading to uncompensated surface spins. PMID:23423492

  3. Substitutional effect of Cr3+ ions on the properties of Mg-Zn ferrite nanoparticles

    NASA Astrophysics Data System (ADS)

    Haralkar, S. J.; Kadam, R. H.; More, S. S.; Shirsath, Sagar E.; Mane, M. L.; Patil, Swati; Mane, D. R.

    2012-11-01

    The effect of Cr3+ substitution in Mg-Zn ferrite, with a chemical formula Mg0.5Zn0.5CrxFe2-xO4 (x=0.0-1.0), synthesized by a sol-gel auto-combustion reaction is presented in this paper. The resultant powders were investigated by various techniques, including X-ray diffractometry (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR), vibrating sample magnetometry (VSM), and DC resistivity. The XRD pattern revealed that the cubic spinel structure is maintained for the all the compositions. The particle sizes measured from XRD and TEM are in good agreement with each other. The cation distribution suggests that Mg2+, Cr3+ and Fe3+ have strong preference towards octahedral B-site. The theoretical lattice constant and experimental lattice constant match each other very well. The IR analysis supports the presently accepted cation distribution. The saturation magnetization decreases linearly with increasing Cr3+ content. Curie temperatures are obtained by the Laoria and AC susceptibility techniques. The dc resistivity has been investigated as a function of temperature and composition.

  4. 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.

  5. 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 ?s, saturation magnetization Ms, and intrinsic coercivity Hci can be obtained at a low sintering temperature of 900°C even much lower. Furthermore, the effective magnetic anisotropy constant Keff and magnetic anisotropy field Ha of the ferrites are calculated from the magnetization curve by the law of approach to saturation. It is suggested that the low-temperature sintered SrFe12O19 ferrites with Ms of 285.6 kA/m and Ha of 1564.6 kA/m possess a significant potentiality for applying in the self-biased low-temperature co-fired ceramics circulators from 34 to 40 GHz.

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

    SciTech Connect

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

    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.

  7. Polyelectrolyte/magnetite nanoparticle multilayers: preparation and structure characterization.

    PubMed

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

    2007-11-20

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

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

    SciTech Connect

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

    2013-02-05

    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.

  9. Preparation and Evaluation of Montelukast Sodium Loaded Solid Lipid Nanoparticles

    PubMed Central

    Priyanka, K; Sathali, A Abdul Hasan

    2012-01-01

    Solid lipid nanoparticles (SLNs) are an alternative carrier system used to load the drug for targeting, to improve the bioavailability by increasing its solubility, and protecting the drug from presystemic metabolism. The avoidance of presystemic metabolism is due to the nano-metric size range, so that the liver cannot uptake the drug from the delivery system and is not metabolized by the liver. Montelukast sodium is an anti-asthmatic drug, because of its poor oral bioavailability, presystemic metabolism, and decreased half-life; it was chosen to formulate as the solid lipid nanoparticle (SLN) system by hot homogenization followed by an ultrasonication method, to overcome the above. Compritol ATO 888, stearic acid, and glyceryl monostearate were used as a lipid matrix and polyvinyl alcohol as a surfactant. The prepared formulations have been evaluated for entrapment efficiency, drug content, in vitro drug release, particle size analysis, scanning electron microscopy, Fourier transform-infrared studies (FT-IR), differential scanning calorimetry (DSC), and stability. Particle size analysis revealed that the SLN prepared from the higher melting point lipid showed a larger particle size and with increased carbon chain length of the fatty acids. Entrapment efficiency (EE) was ranging from 42% to 92%. In vitro release studies showed maximum cumulative drug release was obtained for F 1 (59.1%) containing stearic acid, and the lowest was observed for F 18 (28.1%) containing compritol ATO 888 after 12 h and all the formulations followed first-order release kinetics. FT-IR and DSC studies revealed no interaction between drug and lipids. Studies showed that increase in lipid concentration, increased particle size, EE, and maintained the sustained release of drug. Among all, compritol ATO 888 was chosen as the best lipid for formulating SLN because it had high EE and sustained the drug release. PMID:23112531

  10. (Ni, Zn, Sn) Ru and (Ni, Sn) Sn substituted barium ferrite prepared by mechanical alloying

    NASA Astrophysics Data System (ADS)

    González-Angeles, A.; Lipka, J.; Grusková, A.; Jan?árik, V.; Tóth, I.; Sláma, J.

    2008-06-01

    NiRu, ZnRu, SnRu and SnSn mixtures considerably improved the saturation magnetization, Ms with low substitution values; diminishing quickly at the same times the coercivity, H ci to suitable values for high-density magnetic recording applications. On the other hand, the NiSn mixture also decreased the coercivity rapidly however without enhancing the saturation magnetization. The shown differences on magnetic properties were mainly due both to magnetic nature of divalent ion and to secondary phase apparitions. The mixtures with Sn2 + as partner ion diminished markedly to T c. The tetravalent Ru4 + ion has a special effect on magnetic properties of hexagonal ferrites (increases Ms and diminishes fast H ci with low substitutions).

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

    PubMed Central

    2013-01-01

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

  12. 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.

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

    PubMed

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

    2013-02-01

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

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

    PubMed Central

    Niknejad, Hassan; Mahmoudzadeh, Raziyeh

    2015-01-01

    In the last step of desolvation method for preparation of albumin nanoparticles, glutaraldehyde (GA) is added to stabilize the newly formed nanoparticles. Due to undesirable effects of GA, the objective of this study was to evaluate alternative methods of crosslinking including ultraviolet (UV) irradiation, adding of glucose and combination of both methods. The nanoparticles were prepared by desolvation procedure. Final particle size, zeta potential, FTIR, scanning electron micrograph, cellular uptake and cell toxicity of nanoparticles crosslinked with UV and/or glucose were compared with commonly crosslinked nanoparticles with GA. Moreover, drug release and stability parameters of docetaxel-loaded albumin nanoparticles were investigated. Size of all nanoparticles prepared by different methods was in the same range (100-200 nm). Zeta potential showed the same results except for those treated with UV. The results of FTIR assay were the same for all groups. Although crosslinking by UV or glucose alone resulted in cytotoxic effects, combination of UV and glucose had less cytotoxic effects compared to GA. Cellular uptake of nanoparticles crosslinked with UV + glucose and GA showed similar results. The release of docetaxel from UV + glucose and GA crosslinked nanoparticles showed the same biphasic release. These data support the idea that crosslinking with a combination of UV and glucose can be a promising alternative method for production of docetaxel-loaded albumin nanoparticles with the advantage of omitting toxic GA. PMID:25901145

  15. 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.

  16. 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 CoFe2 O4 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 CoFe2 O4 NPs with Na-tartrate. Moreover, the functionalized CoFe2 O4 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 CoFe2 O4 NPs upon functionalization with tartrate ligands. We believe our developed multifunctional CoFe2 O4 NPs hold great promise for advanced biomedical and technological applications. PMID:25867626

  17. 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

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

    PubMed

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

    2015-05-01

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

  19. Preparation of composite PMMA microbeads hybridized with fluorescent YVO4:Bi3+,Eu3+ nanoparticles

    NASA Astrophysics Data System (ADS)

    Akisada, K.; Noguchi, Y.; Isobe, T.

    2011-10-01

    Poly(methyl methacrylate) (PMMA) microbeads are hybridized with fluorescent YVO4:Bi3+,Eu3+ nanoparticles using the layer-by-layer adsorption technique. The composite beads A are prepared by adsorbing negatively-charged YVO4:Bi3+,Eu3+ nanoparticles onto positively-charged PMMA beads modified with poly(allylamine hydrochloride) (PAH). The composite beads B are prepared by adsorbing nanoparticles onto PMMA beads with multiple alternate layers of PAH and poly(sodium 4-styrenesulfonate) (PSS), i.e., with (PAH/PSS)4/PAH layers. The composite beads C are prepared by adsorbing 300 °C heated nanoparticles with negative charge onto PMMA beads with single PAH layer. These three kinds of composite beads are compared in terms of the amount of adsorbed nanoparticles and the fluorescent intensity.

  20. High Anatase-Rutile Transformation Temperature of Anatase Titania Nanoparticles Prepared by Metalorganic Chemical Vapor Deposition

    Microsoft Academic Search

    Yijun Sun; Takashi Egawa; Liangying Zhang; Xi Yao

    2002-01-01

    Anatase titania nanoparticles with a particle size of about 10 nm are prepared by metalorganic chemical vapor deposition (MOCVD) and the anatase-rutile tranformation of the nanoparticles is investigated and discussed. The results show that anatase-rutile transformation takes place in a wide range of temperature. When annealing time is 1 h, the anatase-rutile transformation temperature of the nanoparticles is as high

  1. Comparison of schemes for preparing magnetic Fe 3O 4 nanoparticles

    Microsoft Academic Search

    Ruoyu Hong; Jianhua Li; Jian Wang; Hongzhong Li

    2007-01-01

    Magnetic Fe3O4 nanoparticles were prepared by means of coprecipitation using NH3·H2O in water and in alcohol, and using NaOH in water. A series of instruments such as SEM, TEM, HRTEM, FT-IR, XRD and VSM were used to characterize the properties of the magnetic nanoparticles. The results indicated that the magnetism of Fe3O4 nanoparticles synthesized using NH3·H2O in water was the

  2. Zinc selenide (ZnSe) nanoparticles prepared by sol-gel method

    Microsoft Academic Search

    Sabar D. Hutagalung; Siaw C. Loo

    2007-01-01

    ZnSe nanoparticles embedded in SiO2 thin films were prepared by sol-gel method using zinc acetate dihydrate, selenic acid and TEOS as source materials. The ZnSe nanoparticles\\/SiO2 thin film composites were deposited on the glass substrate by dip coating technique. FESEM images show that morphology of embedded ZnSe nanoparticles affected by ZnSe\\/SiO2 molar ratio. The optical properties of thin film composite

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

    Microsoft Academic Search

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

    2002-01-01

    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

  4. PEGylated PLGA nanoparticles as protein carriers: synthesis, preparation and biodistribution in rats

    Microsoft Academic Search

    Ya-Ping Li; Yuan-Ying Pei; Xian-Ying Zhang; Zhou-Hui Gu; Zhao-Hui Zhou; Wei-Fang Yuan; Jian-Jun Zhou; Jian-Hua Zhu; Xiu-Jian Gao

    2001-01-01

    The aim of the present work was to assess the merits of PEGylated poly(lactic-co-glycolic acid) (PEG–PLGA) nanoparticles as protein and peptide drugs (PPD) carriers. PEG–PLGA copolymer, which could be used to prepare the stealth nanoparticles or long-circulating nanoparticles, was synthesized with methoxypolyethyleneglycol (MePEG) and PLGA. The structure of PEG–PLGA was confirmed with 1H NMR and Fourier transform infrared (FTIR) spectrum,

  5. Preparation and properties of amorphous titania-coated zinc oxide nanoparticles

    Microsoft Academic Search

    Min-Hung Liao; Chih-Hsiung Hsu; Dong-Hwang Chen

    2006-01-01

    Amorphous TiO2-coated ZnO nanoparticles were prepared by the solvothermal synthesis of ZnO nanoparticles in ethanol and the followed by sol–gel coating of TiO2 nanolayer. The analyses of X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that the resultant ZnO nanoparticles were hexagonal with a wurtzite structure and a mean diameter of about 60nm. Also, after TiO2 coating, the TEM

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

    Microsoft Academic Search

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

    2006-01-01

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

  7. 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 exhibit inhibition towards the tested gram-positive and gram-negative bacteria. PMID:22839208

  8. Development of oxide dispersion strengthened ferritic steel prepared by chemical reduction and mechanical milling

    NASA Astrophysics Data System (ADS)

    Sun, Q. X.; Fang, Q. F.; Zhou, Y.; Xia, Y. P.; Zhang, T.; Wang, X. P.; Liu, C. S.

    2013-08-01

    The oxide dispersion strengthened ferritic steel with a nominal composition of Fe-14Cr-2W-0.5Ti-0.06Si-0.2V-0.1Mn-0.05Ta-0.03C-0.3Y2O3 (14Cr-ODS) was fabricated by sol-gel method in combination with hydrogen reduction, mechanical alloying (MA) and hot isostatic pressing (HIP) techniques. Pure Fe-1.5Y2O3 precursor was obtained by a sol-gel process and a reduction process at 650 °C for 3 h and pure 14Cr-ODS alloy powders were obtained from this precursor and the alloying metallic powders by mechanical alloying. The microstructure analysis investigated by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS) reveal that Y-Ti-O complexes and V-Ti-O complexes with a main particle size of 8 nm are formed in the 14Cr-ODS steel matrix. After HIP sintering the weight and the relative density of the compacted ingots are about 0.8 kg and 99.7%. The uniform elongation and ultimate tensile strength of the ODS steel obtained by HIP after annealing at 1100 °C for 5 h are about 13% and 840 MPa, respectively.

  9. Polymer?Nanoparticle Composites: Preparative Methods and Electronically Active Materials

    Microsoft Academic Search

    P. K. Sudeep; Todd Emrick

    2007-01-01

    The field of nanoparticle?polymer composites is attractive from the standpoint of integrating the key features of both polymers and nanoparticles into hybrid or composite materials. Nanocomposites geared towards electronic and photophysical targets comprise an intriguing subset of the field, and benefit from interdisciplinary efforts in nanoparticle and polymer synthesis, along with methodology that provides the dispersion, orientation, and\\/or the assembly

  10. Effect of Collection Distance on the Lattice Structure of Anatase Titania Nanoparticles Prepared by Metalorganic Chemical Vapor Deposition

    Microsoft Academic Search

    Yijun Sun; Takashi Egawa; Liangying Zhang; Xi Yao

    2002-01-01

    Anatase titania nanoparticles are prepared at 700°C by metalorganic chemical vapor deposition (MOCVD) and the nanoparticles are collected by thermophoretic collection method. The effect of collection distance on the lattice structure of the nanoparticles is investigated, followed by discussion. The results show that the collection distance exerts a significant influence on the lattice structure of the nanoparticles. With decreasing collection

  11. Preparation of Monodispersed Fe-Mo Nanoparticles as the Catalyst for CVD Synthesis of Carbon Nanotubes

    E-print Network

    Wang, Zhong L.

    Received December 19, 2000 Uniform iron-molybdenum nanoparticles were prepared by thermal decomposition of metal carbonyl complexes using a mixture of long-chain carboxylic acid and long-chain amine are highly crystalline iron nanoparticles containing 4% molybdenum. The effects of the concentration

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

    Microsoft Academic Search

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

    2011-01-01

    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

  13. Adsorption of asphaltenes from heavy oil onto in situ prepared NiO nanoparticles.

    PubMed

    Abu Tarboush, Belal J; Husein, Maen M

    2012-07-15

    Removal of asphaltenes from heavy oil improves the quality of oil and makes it easier to process. To this end, Nassar et al. [1] recently showed that NiO nanoparticles have high affinity toward asphaltene adsorption. This investigation, however, involved toluene model solutions and commercially available nanoparticles. In the current work, we show that NiO nanoparticles prepared in situ within heavy oil display much higher affinity toward asphaltenes adsorption, and uptake in the order of 2.8 g asphaltene/g nanoparticles is reported. This uptake way exceeds asphaltene adsorption onto conventional porous adsorbents and commercial nanoparticles from toluene model solutions. Nanoparticle preparation followed a method developed by our group [2], and XRD, EDX, and TEM analyses confirmed the formation of NiO nanoparticles of 12±5 nm mean diameter. Kinetic experiments showed that, while equilibrium could be achieved in less than 2 h for both in situ prepared and commercial NiO particles, much higher adsorption took place onto the in situ prepared ones, owing to their better dispersion. Contrary to literature findings on adsorption from model solutions onto nanoparticles, surface coverage calculations revealed multilayer adsorption. PMID:22560489

  14. Preparation of stable dispersions of Ni nanoparticles using a polymeric dispersant in water

    Microsoft Academic Search

    E. H. Lee; M. K. Lee; C. K. Rhee

    2007-01-01

    After preparation of aqueous dispersions of Ni nanoparticles with a polymeric dispersant, we investigated the effects of several experimental parameters. We characterized the dispersion stability of Ni nanoparticles on the basis of Turbiscan results, visual inspection, and the ? potential. The dispersion stability is unaffected by the molecular weight of the dispersant but it is affected by the concentrations of

  15. New method to prepare very stable and biocompatible fluorescent silica nanoparticles

    PubMed Central

    Ha, Shin-Woo; Camalier, Corinne E.; Beck, George R.

    2010-01-01

    A new synthetic method has been developed to prepare fluorescent silica nanoparticles without employing isothiocyanated dye molecules and (3-aminopropyl)triethoxysilane (APS) for the thiourea linkage formation; the resulting fluorescent silica nanoparticles show excellent photochemical, thermal and pH stabilities and a good biocompatibility with over 85% viability from various cell types. PMID:19436897

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

    Microsoft Academic Search

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

    2000-01-01

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

  17. 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.

  18. Heat generation ability in AC magnetic field of nano MgFe 2O 4-based ferrite powder prepared by bead milling

    Microsoft Academic Search

    Hideyuki Hirazawa; Hiromichi Aono; Takashi Naohara; Tsunehiro Maehara; Mitsunori Sato; Yuji Watanabe

    2011-01-01

    Nanosized MgFe2O4-based ferrite powder having heat generation ability in an AC magnetic field was prepared by bead milling and studied for thermal coagulation therapy applications. The crystal size and the particle size significantly decreased by bead milling. The heat generation ability in an AC magnetic field improved with the milling time, i.e. a decrease in crystal size. However, the heat

  19. Biomedical and environmental applications of magnetic nanoparticles

    Microsoft Academic Search

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

    2010-01-01

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

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

    E-print Network

    Ye, Heechang

    2009-05-15

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

  1. Oxygen electroreduction promoted by quasi oxygen vacancies in metal oxide nanoparticles prepared by photoinduced chlorine doping.

    PubMed

    Wang, Nan; Niu, Wenhan; Li, Ligui; Liu, Ji; Tang, Zhenghua; Zhou, Weijia; Chen, Shaowei

    2015-06-18

    Quasi oxygen-deficient indium tin oxide nanoparticles (ITO NPs) were prepared by photoinduced chlorine doping, and exhibited much enhanced electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline media, as compared with pristine ITO. PMID:26009233

  2. Preparation of PtNi Nanoparticles for the Electrocatalytic Oxidation of Methanol

    E-print Network

    Deivaraj, T.C.

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

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

    E-print Network

    Ye, Heechang

    2009-05-15

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

  4. Cation distribution and enhanced surface effects on the temperature-dependent magnetization of as-prepared NiFe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Atif, M.; Nadeem, M.; Siddique, M.

    2015-05-01

    Nickel ferrite, i.e., NiFe2O4, nanoparticles are synthesized by sol-gel method using urea as a neutralizing agent. The formation of spinel phase and crystal structure of the as-prepared sample is analyzed by X-ray diffraction and transmission electron microscope. In order to confirm phase formation and cation arrangement, room temperature 57Fe Mössbauer spectroscopy is employed. The degree of inversion (i) estimated from the relative peak area is found to be 0.6, which confirms a mixed spinel structure of the as-prepared sample. Zero-field-cooled/field-cooled measurements showed evidence of superparamagnetic behavior associated with the nanosized particles. Hysteresis loop measurements revealed temperature-dependent magnetic properties: The coercive field (H C) decreases with increasing temperature and deviates from the Kneller's law for ferromagnetic nanostructures; and the saturation magnetization (M s) follows modified Bloch's law in the temperature range between 25 and 400 K. However, below 25 K, an abrupt increase in magnetization of nanoparticles is observed. In order to understand this behavior, an additional contribution has to be added to the core magnetization to properly fit the data. Hence, a surface correction term to the Bloch's law is found to describe the temperature dependence of magnetization in the core-shell NiFe2O4 nanoparticles.

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

    Microsoft Academic Search

    Ali Ghasemi; Akimitsu Morisako; Xiaoxi Liu

    2008-01-01

    Strontium ferrite SrFe12O19 (SrM) thick films have been synthesized using a spinning coating sol–gel process. The coating sol was formed from SrFe12O19 powders dispersed in the strontium ferrite raw sol. XRD, TEM, SEM, vibrating sample magnetometer (VSM) and ac susceptometer were employed to evaluate the structure, composition and magnetic properties of SrFe12O19 thick films. The results indicated that a uniform

  6. PLGA nanoparticles prepared by nanoprecipitation: drug loading and release studies of a water soluble drug

    Microsoft Academic Search

    Thirumala Govender; Snjezana Stolnik; Martin C. Garnett; Lisbeth Illum; Stanley S. Davis

    1999-01-01

    The nanoprecipitation technique for preparation of nanoparticles suffers the drawback of poor incorporation of water soluble drugs. The aim of this study was therefore to assess various formulation parameters to enhance the incorporation of a water soluble drug (procaine hydrochloride) into poly(dl-lactide-co-glycolide) (PLGA) nanoparticles prepared by this technique. Approaches investigated for drug incorporation efficiency enhancement included the influence of aqueous

  7. Analyses of factors affecting nickel ferrite nanoparticles synthesis in ultrasound-assisted aqueous solution ball milling.

    PubMed

    Yuan, Zhuang; Chen, Zhen-hua; Chen, Ding; Kang, Zhi-tao

    2015-01-01

    Ball milling experiments were conducted with and without ultrasound wave assistance in deionized water using NiCO3·2Ni(OH)2·4H2O as raw materials. In the reaction process of NiFe2O4 prepared by ultrasound-assisted aqueous solution ball milling, some influencing factors including raw materials, ultrasonic frequency, ball to powder ratio and liquid level were changed. Samples were characterized by X-ray diffraction, fluorescence measurements and electroconductivity detections. The results indicate that more hydroxyl radicals and ions can be generated under the coupling effect of ultrasonic and ball milling. The fluorescence measurements and electroconductivity detections also reflect the reaction speed, allowing for optimal parameters to be determined. PMID:25096301

  8. Preparation and Antibacterial Activity Evaluation of 18-?-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-?-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

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

    PubMed Central

    Wang, Dingsheng; Zhao, Peng; Li, Yadong

    2011-01-01

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

  10. Sample preparation for the quick sizing of metal nanoparticles by atomic force microscopy.

    PubMed

    Vinelli, Alessandra; Primiceri, Elisabetta; Brucale, Marco; Zuccheri, Giampaolo; Rinaldi, Ross; Samorì, Bruno

    2008-12-01

    Two alternative pretreatment methods for depositing metal nanoparticles on mica for atomic force microscopy (AFM) imaging are presented. The treated substrates are flat and clean, thus they are amenable of use to characterize very small nanoparticles. The methods do not require any instrumentation or particular expertise. As they are also very quick, the need for storage of the prepared substrates is avoided altogether. These proposed methods, which are compared with the results of transmission electron microscopy analysis, allow the quick sizing and characterization of nanoparticles with the atomic force microscope and could thus help expanding the user community of nanoparticle researchers who could use the AFM for their characterization needs. PMID:18800349

  11. Magnetic properties of Sr-La system M-type ferrite fine particles prepared by controlling the chemical coprecipitation method

    SciTech Connect

    Yamamoto, Hiroshi; Seki, Hirota

    1999-09-01

    Single phase Sr-La M-type ferrite fine particles were prepared by the chemical coprecipitation and subsequent heat-treatment methods. Optimum magnetic properties were achieved with materials of composition Sr{sub 0.794}{sup 2+}La{sub 0.172}{sup 3+}Fe{sub 0.335}{sup 2+}Fe{sub 11.74}{sup 3+}O{sub 19}, and heat-treatment of 950 C x 2h in air. The magnetic and physical properties are {sigma}{sub s} = 90.5 x 10{sup {minus}6} Wb {center{underscore}dot} m/kg (72.0emu/g), H{sub cJ} = 505.3 kA/m (6.35 kOe), Tc = 454.4 C, the lattice constants a = 0.5882nm, c = 2.303nm, the activation energy = 230.9kJ/mol(55.2kcal/mol), and the average particle size = 0.3{micro}m.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  14. Preparation, Characterization and Application of Fluorescent Terbium Complex-Doped Zirconia Nanoparticles

    Microsoft Academic Search

    Zhiqiang Ye; Mingqian Tan; Guilan Wang; Jingli Yuan

    2005-01-01

    Novel zirconia-based fluorescent terbium nanoparticles have been prepared as a fluorescent nanoprobe for time-resolved fluorescence bioassay. The nanoparticles were prepared in a water-in-oil (W\\/O) microemulsion consisting of a strongly fluorescent Tb3+ complex, N,N,N1, N1-[2,6-bis(3?-aminomethyl-1?-pyrazolyl)-phenylpyridine]tetrakis(acetate)-Tb3+(BPTA-Tb3+), Triton X-100, hexanol, and cyclohexane by controlling co-condensation of Zr(OCH2CH3)4 and ZrOCl2. The characterizations by transmission electron microscopy and fluorometric methods indicate that the nanoparticles are

  15. Preparation of magnetic nanoparticles by pulsed plasma chemical vapor synthesis

    Microsoft Academic Search

    I. Matsui

    2006-01-01

    FePt nanoparticle is expected as a candidate for the magnetic material of the high density recording media. We attempted to synthesize FePt alloy nanoparticles using 13.56 MHz glow discharge plasma with the pulse operation of a square-wave on\\/off cycle of plasma discharge to control the size of nanoparticles. Vapors of metal organics, Biscyclopentadienyl iron (ferrocene) for Fe and (Methylcyclopentadienyl) trimethyl platinum

  16. Structural and magnetic properties of Ni0.8Co0.2-2xCuxMnxFe2O4 spinel ferrites prepared via solution combustion route

    NASA Astrophysics Data System (ADS)

    Jadhav, Pragati; Patankar, Ketaki; Mathe, Vikas; Tarwal, N. L.; Jang, Jae-Hung; Puri, Vijaya

    2015-07-01

    Ni0.8Co0.2-2xCuxMnxFe2O4 ferrites (with x=0.01, 0.03, 0.05, 0.07 and 0.09) were prepared using solution combustion route. X-ray diffraction analysis indicates the presence of the characteristic most intense (311) peak along with other reflections confirming the formation of spinel ferrite in each composition. SEM images show formation of porous structured agglomerates with submicron sized grains. The microstrain measurement of ferrite series is non-linear with variation in dopant concentration for a given magnetic field. The magnetic hysteresis at room temperature indicates the ferrimagnetic behavior of synthesized ferrite system. The magnetic and mechanical properties were seen to be comparatively higher for x=0.07 composition. The presence of sexset in Mössbauer spectra confirms the ferrimagnetic nature of all the ferrites.

  17. Magnetic hard/soft nanocomposite ferrite aligned hollow microfibers and remanence enhancement.

    PubMed

    Song, Fuzhan; Shen, Xiangqian; Liu, Mingquan; Xiang, Jun

    2011-02-01

    The nanocomposite SrFe(12)O(19)/Ni(0.5)Zn(0.5)Fe(2)O(4) ferrite aligned hollow microfibers with the hollow diameter to the fiber diameter estimated about 3/5 have been prepared by the gel precursor transformation process. The nanocomposite binary ferrites with different mass ratios are formed after the precursor calcined at 900°C for 2h, fabricating from SrFe(12)O(19) nanoparticles and Ni(0.5)Zn(0.5)Fe(2)O(4) nanoparticles with a uniform phase distribution. These nanocomposite ferrite microfibers show a combination of magnetic characteristics for the hard (SrFe(12)O(19)) and soft (Ni(0.5)Zn(0.5)Fe(2)O(4)) phase with an enhanced remanence owing to the exchange-coupling interactions. The aligned microfibers exhibit a shape anisotropy. PMID:21144534

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

    SciTech Connect

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

    2005-10-06

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  20. Preparation of L-Alanine Crystals Containing Gold Nanoparticles

    Microsoft Academic Search

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

    2008-01-01

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

  1. [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). PMID:21465817

  2. Physicochemical investigation on mixed alkali metal ferrites prepared by solution combustion method – A comparative study

    Microsoft Academic Search

    B. S. Randhawa; Manik Gupta; H. S. Dosanjh; Nitendar Kumar

    2011-01-01

    Mixed alkali metal nanoferrites of the compositions M0.5?X\\/2ZnXMn0.05Fe2.45?X\\/2O4 (M=Li, Na and K), where x varies from 0?0.5 in steps of 0.1, have been prepared by solution combustion method. Powder X-ray diffraction analysis for all the samples show the formation of single phase cubic spinel structure. The lattice parameter increases linearly with Zn content, which is attributed to ionic size differences

  3. 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 [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Integrated Nanotechnology Research Center (INRC), Khon Kaen University, Khon Kaen 40002 (Thailand); Maensiri, Santi, E-mail: santimaensiri@gmail.com [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)

    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 samples of NiFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} exhibit a superparamagnetic behavior.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. Preparation and characterization of carvacrol loaded polyhydroxybutyrate nanoparticles by nanoprecipitation and dialysis methods.

    PubMed

    Shakeri, Fatemeh; Shakeri, Shahryar; Hojjatoleslami, Mohammad

    2014-04-01

    In this investigation, preparation of carvacrol loaded polyhydroxybutyrate (PHB) nanoparticles was performed by nanoprecipitation and dialysis methods. PHB particles were obtained by nanoprecipitation method without and with low concentration of Tween 80 or pluronic as surfactant. Nano- and micro-sized particles were formed with trimodal distribution and large aggregates. Size and distribution of nanoparticles were decreased when concentration of Tween 80 was increased to 1% (v/v) in water as polar phase. PHB nanoparticles had narrow size (157 nm) with monomodal distribution. Nanoparticles, which were prepared by dialysis method had 140 nm in diameter with monomodal distribution. Carvacrol was used as a lipophilic drug and entrapped in optimized nanoparticles formulation by nanoprecipitation and dialysis methods. Entrapment efficacy was 21% and 11%, respectively. Morphology of PHB nanoparticles was spherical. The results of kinetic release study showed that carvacrol was released for at least 3 days. Release kinetic parameters showed a simple Fickian diffusion behavior for both formulations. Carvacrol loaded PHB nanoparticles had good dispersion into the agar medium and antimicrobial activity against Escherichia coli. This study describes the 1st work on loading of carvacrol into the PHB nanoparticles by nanoprecipitation and dialysis methods. PMID:24621231

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  7. Preparation of compact nanoparticle clusters from polyethylene glycol-coated gold nanoparticles by fine-tuning colloidal interactions.

    PubMed

    Zámbó, Dániel; Radnóczi, György Z; Deák, András

    2015-03-10

    Low-molecular weight polyethylene glycol (PEG) has a lower critical solution temperature well outside the boiling point of water at ambient pressure, but it can be reduced at high ionic strengths. We extend this concept to trigger the clustering of gold nanoparticles through the control of colloidal interactions. At high ionic strengths, low-molecular weight (<2000 Da) mPEG-SH-modified gold nanoparticles show clustering with an increase in the solution temperature. The clustering temperature decreases with an increasing ionic strength. The clustering is attributed to the delicate interplay between the high ionic strength and elevated temperature and is interpreted in terms of chain collapse of the surface-grafted PEG molecules. The chain collapse results in a change in the steric interaction term, whereas the high ionic strength eliminates the double-layer repulsion between the particles. The observations are backed by nanoparticle interaction model calculations. We found that the intermediate attractive potential on the order of a few kT allows the experimental fabrication of compact nanoparticle clusters in agreement with theoretical predictions. The approach presented here has the potential to be extended on the externally triggered preparation of nanoparticle clusters with different types of nanoparticles. PMID:25686160

  8. Z Ferrite Composite

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  9. Characterization of soy protein nanoparticles prepared by high shear microfluidization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soy protein nanoparticles were produced with a microfluidizer and characterized in terms of particle size, size distribution, morphology, rheological properties, and aggregate structure. Three stages of structure breakdown were observed when the soy protein dispersion was passed through the microflu...

  10. FRET-mediated pH-responsive dual fluorescent nanoparticles prepared via click chemistry

    NASA Astrophysics Data System (ADS)

    Ouadahi, Karima; Sbargoud, Kamal; Allard, Emmanuel; Larpent, Chantal

    2012-01-01

    Herein, we report an easy preparation of azide-coated polystyrene-based nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength.Herein, we report an easy preparation of azide-coated polystyrene-based nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength. Electronic supplementary information (ESI) available: Experimental details and figures S1-S16 as mentioned in the text. See DOI: 10.1039/c2nr11413e

  11. Gas sensing properties of ZnFe2O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Misra, Susmita; Ram, S.

    2013-06-01

    Gas sensing performance of ZnFe2O4 ferrite nanoparticles towards various organic volatile compounds is investigated. A self-combustion of a citrate-gel precursor at ˜90 °C in ambient air followed by annealing at 400 °C for 2 h has been explored to prepare a single phase spinel ferrite powder containing granular nanoparticles of average 23 nm diameters. A powder compact measures chemiresistive sensitivity of 59, 51, and 67% for organic vapor-analytes methanol, ethanol, and acetone respectively of 200 ppm at 250 °C. Excellent sensitivity of the granular nanoparticles results due to a large surface area to volume ratio effect.

  12. Preparation and Characterisation of Chemically Grown Iron Cobalt (FeCo) Nanoparticles

    NASA Astrophysics Data System (ADS)

    Yong, B. E.; Kang, C. H.; Hoo, J. X.; Lim, K. P.; Ong, B. H.

    2009-06-01

    Nanosized magnetic particles are the subject of research interest because of their potential in high density magnetic recording. In this paper, iron cobalt (FeCo) magnetic nanoparticles are synthesized by co-precipitation and the magnetic and structural properties of the nanoparticles are investigated. The particles are formed through simultaneous reduction of Iron (III) chloride and cobalt (II) chloride in the presence of reducing agents. Growth of the particles size and shape due to various experimental conditions are investigated. Chemical synthesis has been successfully used to prepare monodispersed FeCo nanoparticles in the range of 10 to 20 nm. These nanoparticles are superparamagnetic at room temperature. The size and structure variations are analyzed by Transmission Electron Microscopy (TEM) and X-Ray Diffractions (XRD). The magnetic properties of the nanoparticles are characterised by saturation magnetization, remanent magnetization and coercivity from hysteresis loop by Vibrating Sample Magnetometer (VSM).

  13. Preparation of gold nanoparticles-agarose gel composite and its application in SERS detection.

    PubMed

    Ma, Xiaoyuan; Xia, Yu; Ni, Lili; Song, Liangjing; Wang, Zhouping

    2014-01-01

    Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-Vis-NIR absorption spectroscopy. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules (NBA, MBA, 1NAT). Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal. Furthermore, the gel could be cleaned with washing solution and recycling could be achieved for Raman detection. PMID:24368285

  14. Microbial mediated preparation, characterization and optimization of gold nanoparticles

    PubMed Central

    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 R2 value was calculated to be 0.9999 indicating the accuracy and ability of the polynomial model. It can be concluded that the use of multivariate analysis facilitated to find out the optimum conditions for the biosynthesis of gold nanoparticles induced by Penicillium crustosum in a time and cost effective process. The current approach suggested that rapid synthesis of gold nanoparticles would be suitable for developing a biological process for mass scale production of formulations. PMID:25763059

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  16. Platinum tungsten oxide (Pt-WO 3 ) nanoparticles: their preparation in glycol and electrocatalytic properties

    Microsoft Academic Search

    Kwok-Ying Tsang; Tung-Chun Lee; Jiawen Ren; Kwong-Yu Chan; Hengzhi Wang; Huanting Wang

    2006-01-01

    A method to prepare supported nanoparticles of Pt–WO3 with composition control in nanoscales is presented. Transmission electron microscopy shows crystal domains in the nanoparticles, which have a narrow size distribution. Energy dispersive X-ray analyses performed in different regions show good uniformity in the Pt?:?W ratio, which correlates linearly with the Pt?:?W ratio in the precursor. Platinum is mostly present in

  17. PREPARATION OF ZINC OXIDE NANOPARTICLE VIA UNIFORM PRECIPITATION METHOD AND ITS SURFACE MODIFICATION BY METHACRYLOXYPROPYLTRIMETHOXYSILANE

    Microsoft Academic Search

    Erjun Tang; Baoyong Tian; Erli Zheng; Cuiyan Fu; Guoxiang Cheng

    2008-01-01

    Zinc oxide nanoparticles were prepared by uniform precipitation using urea hydrolysis. The ZnO precursor was slowly deposited from aqueous solution. Anionic surfactant was added into solution to block ZnO crystal growth and its agglomeration. Then ZnO nanoparticles were synthesized by the calcination of the precursor at high temperature. Transmission electron microscope (TEM) observation and particle size analyzer demonstrated that the

  18. Novel biocompatible composite (Chitosan–zinc oxide nanoparticle): Preparation, characterization and dye adsorption properties

    Microsoft Academic Search

    Raziyeh Salehi; Mokhtar Arami; Niyaz Mohammad Mahmoodi; Hajir Bahrami; Shooka Khorramfar

    2010-01-01

    In this paper, the preparation, characterization and dye adsorption properties of novel biocompatible composite (Chitosan–zinc oxide nanoparticle) (CS\\/n-ZnO) were investigated. Zinc oxide nanoparticles were immobilized onto Chitosan. Physical characteristics of CS\\/n-ZnO were studied using Fourier transform infra-red (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray spectroscopy (WDX). Two textile dyes, Direct Blue 78 (DB78) and Acid

  19. Preparation of Perylenediimide Nanoparticle Colloids by Laser Ablation in Water and Their Optical Properties

    Microsoft Academic Search

    Ryohei Yasukuni; Takayuki Hironaka; Tsuyoshi Asahi

    2010-01-01

    Fluorescent nanoparticles of N,N '-bis(2,5-di-tert-butylphenyl)-3,4,9,10-perylenedicarboximide (DBPI) were fabricated by laser ablation of its microcrystals dispersed in pure water, and their optical extinction and fluorescence spectra were investigated. Colloidal nanoparticles withmean sizes of 30 to 80 nm were prepared without molecular decomposition by tuning the fluence of the irradiating laser. Spectral simulation based on Mie theory explains the difference in the

  20. Methoxypolyethylene Glycol Cyanoacrylate-Docosyl Cyanoacrylate Graft Copolymer: Synthesis, Characterization, and Preparation of Nanoparticles

    Microsoft Academic Search

    Xiuli Wei; Hui Yan; Huinan Xu; Wei Wu

    2006-01-01

    Amphiphilic poly (MePEG-co-alkyl cyanoacrylate) copolymers have been studied as carriers for stealth nanoparticles. A promising area is nanoparticles prepared using copolymers with both high ratio of PEG blocks and sufficient hydrophobicity. In this study, poly (MePEG cyanoacrylate-co-docosyl cyanoacrylate) copolymer with longer alkyl chains has been synthesized by condensing MePEG cyanoacetate and docosyl cyanoacetate with formaldehyde in the presence of pyrrolidine.

  1. Preparation and characterization of acrylic polymer–nanogold nanocomposites from 3-mercaptopropyltrimethoxysilane encapsulated gold nanoparticles

    Microsoft Academic Search

    Chao-Ching Chang; Pei-Huan Chen; Chih-Ming Chang

    2008-01-01

    In this study, acrylic polymer–nanogold nanocomposites and their cast films were prepared from an acrylic copolymer and 3-mercaptopropyltrimethoxysilane\\u000a (MPS) stabilized gold nanoparticles by a sol–gel reaction. The acrylic copolymer was synthesized from methyl methacrylate\\u000a (MMA) and 3-(trimethoxysilyl)propyl methacrylate (MSMA). The Si–OMe groups of MPS on the surface of gold nanoparticles (MPS–Au)\\u000a provided the further reaction with the same groups of

  2. Preparation of Concentrated Stable Fluids Containing Silver Nanoparticles in Nonpolar Organic Solvent

    Microsoft Academic Search

    Fu Xun; Yu Wei; Lin Yusheng; Wang Debao; Shi Huaqiang; Yan Fengyuan

    2005-01-01

    Stable fluids containing silver nanoparticles in kerosene have been prepared by the extraction?reduction method. Silver nitrate was extracted in nonpolar solvent by thio?substituted phosphinic acid extractant Cyanex 302, and then Ag was reduced by solid KBH4. In order to enhance the loading content of silver nanoparticles in the fluids, a tri?block copolymer (PEO)20(PPO)70(PEO)20 was added into the organic phase before

  3. 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.

  4. Magnetic and Structural Properties of Nanosized Magnesium Doped Zinc Ferrite Synthesized by Citrate Precursor Method

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; Bansal, Shweta Dikshu; Singh, Simranjit

    2011-12-01

    Nanoparticles of MgxZn1-xFe2O4 ferrite (where x = 0.2, 0.4, 0.5,) are synthesized via citrate precursor method and then all the samples are sintered at 600 °C for 1 hour. The prepared samples are characterized through XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), TEM (transmission electron microscope) and VSM (vibrating sample magnetometer). The M-H curves show evidence of a superparamagnetic (SPM) regime in the synthesized ferrites.

  5. Preparation, characterization, and in vitro release investigation of lutein\\/zein nanoparticles via solution enhanced dispersion by supercritical fluids

    Microsoft Academic Search

    Daode Hu; Changchun Lin; Liang Liu; Sining Li; Yaping Zhao

    Solution enhanced dispersion by supercritical fluids (SEDS) was applied for the production of lutein\\/zein nanoparticles. The effects of the process variables on the morphology, drug loading, entrapment efficiency, and mean particle size of the nanoparticles were investigated. The results showed that the nanoparticles with high drug loading and high entrapment efficiency were prepared by SEDS process. Temperature, pressure, ratio of

  6. Preparation and biomedical application of a non-polymer coated superparamagnetic nanoparticle

    PubMed Central

    Du, Lin; Chen, Jianzhao; Qi, Yanting; Li, Dan; Yuan, Chonggang; Lin, Marie C; Yew, David T; Kung, Hsiang-Fu; Yu, Jimmy C; Lai, Lihui

    2007-01-01

    We report the preparation of a non-polymer coated superparamagnetic nanoparticle that is stable and biocompatible both in vitro and in vivo. The non-polymer, betaine, is a natural methylating agent in mammalian liver with active surface property. Upon systemic administration, the nanoparticle has preferential biodistribution in mammalian liver and exhibits good reduction of relaxivity time and negative enhancement for the detection of hepatoma nodules in rats using MRI. Our data demonstrate that the non-polymer coated superparamagnetic nanoparticle should have potential applications in biomedicine. PMID:18203447

  7. Preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels.

    PubMed

    Im, Hee-Jung; Lee, Byung Cheol; Yeon, Jei-Won

    2013-11-01

    Ag nanoparticles, used for halogen (especially iodine) adsorption and an evaluation of halogen behavior, were embedded in synthesized inorganic-organic hybrid gels. In particular, an irradiation method using an electron beam plays a part in introducing Ag nanoparticles to the organofunctionalized silica gels from AgNO3 solutions in a simple way at atmospheric pressure and room temperature. For preparation of the Ag nanoparticle-embedded inorganic-organic hybrid gels, ligands of ethylenediamine (NH2CH2CH2NH-, TMSen) and mercapto (HS-) functionalized three-dimensional porous SiO2 sol-gels were first synthesized through hydrolysis and condensation reactions, and Ag nanoparticles were then embedded into the ethylenediamine- and mercapto-anchored silica gels each, through electron-beam irradiation. The addition of ligands yielded larger average pore sizes than the absence of any ligand. Moreover, the ethylenediamine ligand led to looser structures and better access of the Ag nanoparticles to the ethylenediamine-anchored gel. As a result, more Ag nanoparticles were introduced into the ethylenediamine-anchored gel. The preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels are discussed in detail. PMID:24245307

  8. Preparation, characterization of NiB amorphous alloy nanoparticles and their catalytic performance in hydrogenation reactions.

    PubMed

    Huo, Weitao; Yuan, Hongjing; Jia, Mingjun; Wu, Ping; Cong, Dequan; Wang, Zhenlu; Liu, Yunling; Zhang, Wenxiang

    2013-08-01

    Nano-sized NiB amorphous alloy catalysts were prepared by chemical reduction method through introducing AlCl3 into the preparation system. The formation of Al(OH)3 sol plays an important role in inhibiting the agglomeration of NiB nanoparticles during the reduction process. The NiB amorphous alloy nanoparticles could be obtained after the removal of Al(OH)3 by NaOH solution. The particle sizes of these alloy catalysts could be adjusted in a certain range by changing the amount of AlCl3. The resultant NiB catalysts exhibited high catalytic activity in the hydrogenation of furfural and methyl isobutyl ketone, which is much higher than the NiB amorphous alloy catalyst prepared by direct reduction method. The excellent catalytic performance of NiB nanoparticles is apparently owing to the smaller particle size and higher surface area. PMID:23882862

  9. Preparation of metallic copper nanoparticles in aqueous solution and their bonding properties

    NASA Astrophysics Data System (ADS)

    Kobayashi, Y.; Shirochi, T.; Yasuda, Y.; Morita, T.

    2011-03-01

    This paper describes a method for preparing metallic Cu nanoparticles in aqueous solution, and a bonding technique using the nanoparticles. Preparation of the Cu particle colloid solution was performed in water at room temperature in air using a copper source (0.01 M CuCl 2), a reducing reagent (0.1-1.0 M hydrazine), and stabilizers (0-1.5 × 10 -3 M citric acid and 5.0 × 10 -3 M cetyltrimethylammonium bromide). The metallic Cu nanoparticles with a size of 71 ± 14 nm were prepared at 0.4 M hydrazine and 5 × 10 -4 M citric acid. A stage and a plate of metallic Cu were successfully bonded under annealing at 400 °C and pressurizing at 1.2 MPa for 5 min in H 2 gas with help of the metallic Cu particles. A shear strength required for separating the bonded Cu substrates was as high as 28.6 MPa.

  10. Preparation and in vitro evaluation of mucoadhesion and permeation enhancement of thiolated chitosan-pHEMA core-shell nanoparticles.

    PubMed

    Moghaddam, Firooze Aghaei; Atyabi, Fatemeh; Dinarvand, Rassoul

    2009-06-01

    The aim of the present work was to evaluate the in vitro mucoadhesion and permeation enhancement properties of thiolated chitosan (chitosan-glutathione) coated poly(hydroxyl ethyl methacrylate) nanoparticles. Core-shell nanoparticles were prepared by radical emulsion polymerization method initiated by cerium(IV) ammonium nitrate. Different molecular weights of chitosan were utilized for nanoparticles preparation. The physicochemical properties of nanoparticles were characterized by size, zeta potential, and thiol content. Incorporation of fluorescein isothiocyanate dextran (FD4, MW 4400 Da), which was used as the model macromolecule, was achieved by incubation method. The intestinal mucoadhesion and penetration enhancement properties of nanoparticles were investigated using excised rat jejunum. All nanoparticle systems showed mucoadhesion and improved apparent permeation coefficient (P(app)) of FD4. Nanoparticles prepared by thiolated chitosan with medium molecular weight revealed the most mucoadhesion and penetration enhancement properties. PMID:19186220

  11. 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.

  12. 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.

  13. Preparation and characterization of chitosan/?-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/?-cyclodextrin (LMW CS/CD) nanoparticles were prepared using ionotropic gelation method and characterized in terms of size, zeta potential, polydispersity index, morphology, loading efficiency and cytotoxicity against the CT-26 colon carcinoma cell line.All prepared particles were spherical in shape and nano-sized (171.3±2.165 nm, PdI: 0.231±0.014) and exhibited a positive zeta potential (34.3±1.55). The nanoparticles demonstrated good DNA encapsulation efficiencies (83.315%±2.067). Prepared pUMVC3-hIL12 loaded LMW CS/CD nanoparticles showed no cell toxicity in murine CT-26 colon carcinoma cells. At the concentration of 0.1 µg/ml of nanoparticles, the transfection ability was obviously higher than that of the naked DNA.LMW CS/CD-plasmid DNA nanoparticles encoding IL-12 prepared using ionotropic gelation method with no toxic effect on the tested cells can be considered as a basis for further gene delivery studies both in vitro and in vivo to enhance the expression of IL-12. PMID:23447042

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  16. Synthesis of cobalt ferrite (CoFe2O4) nanoparticles using combustion, coprecipitation, and precipitation methods: A comparison study of size, structural, and magnetic properties

    NASA Astrophysics Data System (ADS)

    Houshiar, Mahboubeh; Zebhi, Fatemeh; Razi, Zahra Jafari; Alidoust, Ali; Askari, Zohreh

    2014-12-01

    In this work the cobalt ferrite (CoFe2O4) nanoparticles are synthesized using three different methods; combustion, coprecipitation, and precipitation. Size, structural, and magnetic properties were determined and compared using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). XRD data analysis showed an average size of 69.5 nm for combustion, 49.5 nm for coprecipitation, and 34.7 nm for precipitation samples which concorded with SEM images. XRD data further revealed a reverse cubic spinel structure with the space group Fd-3m in all three samples. VSM data of samples showed a saturation point in the magnetic field of less than 15 kOe. Magnetization saturation (Ms) was 56.7 emu/g for combustion synthestized samples, 55.8 emu/g for coprecipitation samples, and 47.2 emu/g for precipitation samples. Coercivity (Hc) was 2002 Oe for combustion synthestized samples, 850 Oe for coprecipitation samples, and 233 Oe for precipitation samples. These results show that various methods of nanoparticle synthesis can lead to different particle sizes and magnetic properties. Hc and Ms are greatest in the combustion method and least in precipitation method.

  17. Dielectric behavior and a. c. conductivity studies on Co0.4Ni0.6Fe2O4 nanoparticles synthesized via combustion method

    Microsoft Academic Search

    B. J. Madhu; K. Bindu; S. Hamsa; C. P. Sowmya; A. Manjunath; G. H. Virupakshappa; B. Shruthi

    2011-01-01

    Cobalt-Nickel (Co0.4Ni0.6Fe2O4) ferrite nanoparticles were prepared by solution combustion method using cobalt nitrate & nickel nitrate as oxidizers and urea as a fuel. The structures of the sample were studied with X-ray diffraction (XRD) using Cu-Ka radiation. The X-ray diffraction analysis revealed the nanocrystalline nature in the prepared ferrite samples. The dependence of dielectric properties such as dielectric constant (??)

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

    Microsoft Academic Search

    S. Nasir; M. Anis-ur-Rehman

    2011-01-01

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

  19. Pt nanoparticles over PEDOT/carbon composites prepared by supercritical carbon dioxide deposition

    NASA Astrophysics Data System (ADS)

    Bozkurt, Gamze; Memio?lu, Fulya; Bayrakçeken, Ay?e

    2014-11-01

    In this study, firstly, polyethylenedioxythiophene (PEDOT)/carbon (C) composite material was synthesized by oxidative chemical polymerization. Then, PEDOT/C supported platinum (Pt) nanoparticles were prepared by using supercritical carbon dioxide (scCO2) deposition method. The prepared composite and catalyst were characterized by using BET, TGA, XRD and TEM techniques. The Pt loading over the support was achieved as 10%. TEM results showed that highly dispersed and small nanoparticles over the composite material can be obtained by using scCO2 deposition method.

  20. 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-?-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 docetaxel. PMID:22114486

  1. Preparation of nanodiamonds from carbon nanoparticles at atmospheric pressure

    E-print Network

    Kamali, Ali Reza; Fray, Derek J.

    2015-01-23

    is preferable inside a carbon nanotube (CNT) or nanoparticle due to the effect of the surface tension brought about by the nanometre-sized curvature of carbon nanomaterials11. Furthermore, sp3 bonds have been observed in used graphitic anodes retrieved from... and nanoparticles could still be clearly seen in the SEM images of the heated samples (see Fig. 1c). The sample heated to 570ºC, which is beyond the first exothermic peak, experienced a massive weight loss. Moreover, no carbon nanomaterial could be indentified...

  2. 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…

  3. Properties of magnetic nanoparticles prepared by co-precipitation.

    PubMed

    Kim, Jong-Hee; Kim, Sang-Mun; Kim, Yong-Il

    2014-11-01

    Magnetic nanoparticles were synthesized by the addition of ammonium hydroxide to an iron chloride solution by chemical co-precipitation. In order to examine systematically the crystal phase, average size, and magnetic properties of the magnetic nanoparticles, the following were used as experimental parameters: molar ratio of Fe2+/Fe3+, composition of the iron chloride solution, amount of ammonium hydroxide, reaction temperature, and oxidation time of reaction precipitate. In the processing conditions of Fe2+/Fe3+ ratios of 0.5 and 1.0, iron chloride solutions of 0.1-0.8 m, NH4OH molar ratios of 6-14R, reaction temperatures of 25-80 degrees C, and oxidation times of 5-90 min, the co-precipitated nanoparticles were observed to exist as a single phase of Fe3O4. The average size of the particles was approximately 20 nm, and their magnetization was saturated at about 60 emu/g with superparamagnetism. When the iron chloride solution comprised only Fe2+ ions, the oxidation of the reaction precipitates also developed a Fe3O4 phase. However, the particle size reached 78 nm with increasing oxidation times, and the saturation magnetization increased significantly to 82 emu/g while its coercive force was 150 Oe, which indicated that the nanoparticles were paramagnetic. PMID:25958595

  4. 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.

  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. PMID:25280693

  6. 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 ?m to about 60-120 nm, and the crystal pattern changed from A-type to B+V-type. The StNPs prepared with 15% starch slurry had the highest degree of crystallinity at 55.41%. The eco-friendly prepared nanoparticles could be widely used in biomedical applications and development of new materials. PMID:24874379

  7. Functionalized magnetic nanoparticles for sample preparation in proteomics and peptidomics analysis.

    PubMed

    Li, Yan; Zhang, Xiangmin; Deng, Chunhui

    2013-11-01

    Sample preparation is a fundamental step in the proteomics and peptidomics workflow. Due to their good biocompatibility, superparamagnetic property, and high binding capacity, magnetic nanoparticles (MNPs) functionalized with different active moieties have been widely applied in recent years in various sample preparation procedures in proteomics and peptidomics analysis. The magnetic cores of the MNPs facilitate elegant handling using only magnetic devices and their small diameters are advantageous for increasing the sensitivity when using subsequent mass spectrometry (MS) analysis or gel electrophoresis. This review mainly focuses on overviewing present advances in the preparation and application of functionalized magnetic nanoparticles for sample preparation in proteomics and peptidomics analysis, including protein digestion, enrichment of low-abundance peptides/proteins and specific enrichment of peptides/proteins with post-translational modifications, such as phosphorylation and glycosylation. PMID:23933677

  8. 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

  9. 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.

  10. 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

  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

    2011-01-01

    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

  12. 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

  13. 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.

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

    SciTech Connect

    Pohl, D.; Surrey, A.; Schultz, L. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany); TU Dresden, Institute of Condensed Matter Physics, D-01062 Dresden (Germany); Rellinghaus, B. [IFW Dresden, Institute for Metallic Materials, P.O. Box 270116, D-01171 Dresden (Germany)

    2012-12-24

    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.

  15. Silica coating of Co–Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone)

    Microsoft Academic Search

    Yoshio Kobayashi; Hidekazu Kakinuma; Daisuke Nagao; Yasuo Ando; Terunobu Miyazaki; Mikio Konno

    2009-01-01

    This article describes a method for silica coating of Co–Pt alloy nanoparticles prepared in the presence of poly(vinylpyrrolidone)\\u000a (PVP) as a stabilizer. The Co–Pt nanoparticles were prepared in an aqueous solution at 25–80 °C from CoCl2 (3.0 × 10?4 M), H2PtCl6 (3.0 × 10?4 M), PVP (0–10 g\\/L), and NaBH4 (4.8 × 10?3–2.4 × 10?2 M). The silica coating was performed for the Co–Pt nanoparticle colloid containing the PVP ([Co] = [Pt] = 3.0 × 10?5 M) at 25 °C in

  16. Diclofenac sodium-loaded solid lipid nanoparticles prepared by emulsion\\/solvent evaporation method

    Microsoft Academic Search

    Dongfei LiuSunmin; Sunmin Jiang; Hong Shen; Shan Qin; Juanjuan Liu; Qing Zhang; Rui Li; Qunwei Xu

    2011-01-01

    The preparation of solid lipid nanoparticles (SLNs) suffers from the drawback of poor incorporation of water-soluble drugs.\\u000a The aim of this study was therefore to assess various formulation and process parameters to enhance the incorporation of a\\u000a water-soluble drug (diclofenac sodium, DS) into SLNs prepared by the emulsion\\/solvent evaporation method. Results showed that\\u000a the entrapment efficiency (EE) of DS was

  17. Preparation of carbon nanotubes and nano-particles by microwave plasma-enhanced chemical vapor deposition

    Microsoft Academic Search

    Xizhang Wang; Zheng Hu; Xin Chen; Yi Chen

    2001-01-01

    Systematic preparation of carbon nanotubes (CNTs) and nanoparticles (CNPs) on Fe (or Co; Ni)\\/?-Al2O3 by microwave plasma-enhanced chemical vapor deposition (MW-PECVD) has been reported with a mixture of CH4, H2, and Ar as precursors. By regulating the preparation parameters; Various carbon nanostructures including several novel CNTs have be obtained. The outstanding feature of this new approach is the low synthesis

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

    Microsoft Academic Search

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

    2009-01-01

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

  19. 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 tissue. PMID:24106420

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

    PubMed

    Hussain, Shokit; Khan, Zaheer

    2014-07-01

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

  1. Preparation and characterization of functional silica hybrid magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Digigow, Reinaldo G.; Dechézelles, Jean-François; Dietsch, Hervé; Geissbühler, Isabelle; Vanhecke, Dimitri; Geers, Christoph; Hirt, Ann M.; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2014-08-01

    We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a comprehensive synthetic study is carried out and completed by a detailed characterization of hybrid particles' size and morphology, surface properties, and magnetic responses using different techniques. Depending on the mass ratio of SPIONs and the two silanes (TEOS and APTES), we were able to adjust the number of surface amino groups and tune the magnetic properties of the superparamagnetic hybrid particles.

  2. Preparation of self-assembled silk sericin nanoparticles

    Microsoft Academic Search

    Kwang Yong Cho; Jae Yu Moon; Yong Woo Lee; Kwang Gill Lee; Joo Hong Yeo; Hae Yong Kweon; Ki Ho Kim; Chong Su Cho

    2003-01-01

    Silk sericin (SS) possessing moisture-retaining property was reacted with activated poly(ethylene glycol) (PEG) to obtain self-assembled SS nanoparticles. The aliphatic and aromatic hydroxyl groups of serine and tyrosine residues as the reaction sites in SS were clarified by amino acid analysis and 1H NMR spectroscopy, respectively. From IR and circular dichroism (CD) measurements, introduction of PEG into SS induced the

  3. Preparation, characterization and in vivo evaluation of amorphous atorvastatin calcium nanoparticles using supercritical antisolvent (SAS) process

    Microsoft Academic Search

    Min-Soo Kim; Shun-Ji Jin; Jeong-Soo Kim; Hee Jun Park; Ha-Seung Song; Reinhard H. H. Neubert; Sung-Joo Hwang

    2008-01-01

    In this work, amorphous atorvastatin calcium nanoparticles were successfully prepared using the supercritical antisolvent (SAS) process. The effect of process variables on particle size and distribution of atorvastatin calcium during particle formation was investigated. Solid state characterization, solubility, intrinsic dissolution, powder dissolution studies and pharmacokinetic study in rats were performed. Spherical particles with mean particle size ranging between 152 and

  4. 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...

  5. Preparation of supported gold nanoparticles by a modified incipient wetness impregnation method

    E-print Network

    Boyer, Edmond

    procedure of impregnation of oxide supports with chloroauric acid, which is well-known to lead to large gold1 Preparation of supported gold nanoparticles by a modified incipient wetness impregnation method particles, is followed by a step of washing with ammonia, small gold particles (3-4 nm) can be obtained

  6. Preparation, characterization, and functional analysis of zinc oxide nanoparticle-coated cotton fabric for antibacterial efficacy

    Microsoft Academic Search

    Anita Asokan Subash; Koushik Venkatraman Chandramouli; T. Ramachandran; R. Rajendran; Mahalakshmi Muthusamy

    2012-01-01

    Nanotechnology is an emerging interdisciplinary technology and nanostructures capable of enhancing the physical properties of conventional textiles in areas such as antimicrobial properties, water repellence, soil resistance, antistatic, anti-infrared and flame-retardant properties, dye ability, color fastness, and strength of textile materials. The studies were carried out in order to fine tune the preparation of zinc oxide nanoparticles (NPs) for special

  7. Preparation, characterization, and functional analysis of zinc oxide nanoparticle-coated cotton fabric for antibacterial efficacy

    Microsoft Academic Search

    Anita Asokan Subash; Koushik Venkatraman Chandramouli; T. Ramachandran; R. Rajendran; Mahalakshmi Muthusamy

    2011-01-01

    Nanotechnology is an emerging interdisciplinary technology and nanostructures capable of enhancing the physical properties of conventional textiles in areas such as antimicrobial properties, water repellence, soil resistance, antistatic, anti-infrared and flame-retardant properties, dye ability, color fastness, and strength of textile materials. The studies were carried out in order to fine tune the preparation of zinc oxide nanoparticles (NPs) for special

  8. Preparation of lysozyme imprinted magnetic nanoparticles via surface graft copolymerization.

    PubMed

    Wang, Yanxia; Chai, Zhihua; Sun, Yingjuan; Gao, Ming; Fu, Guoqi

    2015-08-01

    Molecular imprinting as a facile and promising separation technique has received considerable attention because of their high selectivity for target molecules. In this study, we imprinted lysozyme (Lys) on the surface of core-shell magnetic nanoparticles via surface imprinting. The magnetic supports were functionalized with maleic acid and then coated with imprinted polymer layers. The structure and morphology of the resulting magnetic imprinted nanoparticles were characterized by transmission electron microscopy, scanning electron microscope, dynamic light scatting, vibrating sample magnetometer, and thermogravimetric analysis. Binding experiments were carried out to evaluate the properties of magnetic molecularly imprinted polymers (magnetic MIPs) and magnetic non-molecularly imprinted polymers (magnetic NIPs). The protein adsorption results showed that the magnetic MIPs had significant specific recognition toward the template protein and could be easily separated from solution by an external magnetic field. Moreover, the MIPs exhibited fast kinetics for the rebinding of the target protein due to the thin-imprinted layer and showed good reusability by four adsorption-desorption cycles. Therefore, the surface imprinting approach combined with magnetic nanoparticles provided an easy and fast method for the specific recognition of Lys. PMID:26073534

  9. 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-? (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 ? 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.

  10. Organically capped silicon nanoparticles with blue photoluminescence prepared by hydrosilylation followed by oxidation.

    PubMed

    Hua, Fengjun; Erogbogbo, Folarin; Swihart, Mark T; Ruckenstein, Eli

    2006-04-25

    A facile method of preparing stable blue-emitting silicon nanoparticles that are dispersible in common organic solvents is presented. Oxidation of yellow-emitting silicon nanoparticles with an organic monolayer grafted to their surface, using either UV irradiation in solution or heating in air, converted them to blue-emitting particles. The evolution of the PL spectrum and infrared absorption spectrum of the particles was followed during the oxidation process. The PL spectrum showed a decrease in the PL emission peak near 600 nm and the appearance and increase in intensity of a PL emission peak near 460 nm rather than a smooth blue shift of the emission spectrum from yellow to blue. The organic monolayer grafted to the particle surface was not degraded by this oxidation process, as demonstrated by FTIR and NMR spectroscopy. Similar results were achieved for particles with styrene, 1-octene, 1-dodecene, and 1-octadecene grafted to their surface, demonstrating that it is the silicon nanocrystal, and not the organic component, that is essential to this process. The organic monolayer allows the nanoparticles to form stable, clear colloidal dispersions in organic solvents and provides for the possibility of further chemical functionalization of the particles. Combined with previous work on organically grafted silicon nanoparticles with green through near-infrared emission, this enables the efficient and scalable preparation of stable colloidal dispersions of organically grafted silicon nanoparticles with emission spanning the entire visible spectrum. PMID:16618188

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

    SciTech Connect

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

    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.

  12. 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

  13. 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

  14. Electrical properties of strontium ferrites for industrial applications

    Microsoft Academic Search

    A. Tawfik; M. M. Barakat

    1988-01-01

    The polycrystalline ferrites have very good dielectric properties and are dependent on several factors, including the method of preparation, the sintering temperature and the sintering atmosphere. In the process of preparation of ferrites in the polycrystalline form the ferrite powder is sintered under slightly reducing conditions. Consequently the divalent iron produced in the bulk of the material forms highconductivity grains

  15. 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

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

    PubMed

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

    2012-10-26

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

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

    SciTech Connect

    Mohandes, Fatemeh [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167, Islamic Republic of Iran (Iran, Islamic Republic of)

    2013-10-15

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

  18. Chitosan-poly (lactide-co-glycolide) (CS-PLGA) nanoparticles containing metformin HCl: preparation and in vitro evaluation.

    PubMed

    Gundogdu, Nuran; Cetin, Meltem

    2014-11-01

    In this study, the preparation and in vitro characterisation of metformin HCl-loaded CS-PLGA nanoparticles (NPs) were aimed. The prepared nanoparticles (blank nanoparticles (C-1), 50 mg of metformin HCl loaded nanoparticles (C-2) and 75 mg of metformin HCl loaded nanoparticles (C-3) ranged in size from 506.67±13.61 to 516.33±16.85 nm and had surface charges of 22.57±1.21 to 32.37±0.57 mV. Low encapsulation efficiency was observed for both nanoparticle formulations due to the leakage of metformin HCl to the external medium during preparation of nanoparticles. Nanoparticle formulations showed highly reproducible drug release profiles. ~20% of metformin HCl was released within 30 minutes and approximately 98% of the loaded metformin HCl was released at 144 hours in a phosphate buffer (PB; pH 6.8). No statistically significant difference was noted between the in vitro release profiles of the nanoparticles (C-2 and C-3) containing metformin HCl. Also, nanoparticles were characterised using FT-IR and DSC. PMID:25362616

  19. Holmium Nanoparticles: Preparation and In Vitro Characterization of a New Device for Radioablation of Solid Malignancies

    PubMed Central

    Bult, Wouter; Varkevisser, Rosanne; Soulimani, Fouad; Seevinck, Peter R.; de Leeuw, Hendrik; Bakker, Chris J. G.; Luijten, Peter R.; van het Schip, Alfred D.; Hennink, Wim E.

    2010-01-01

    ABSTRACT Purpose The present study introduces the preparation and in vitro characterization of a nanoparticle device comprising holmium acetylacetonate for radioablation of unresectable solid malignancies. Methods HoAcAc nanoparticles were prepared by dissolving holmium acetylacetonate in chloroform, followed by emulsification in an aqueous solution of a surfactant and evaporation of the solvent. The diameter, surface morphology, holmium content, and zeta potential were measured, and thermal behavior of the resulting particles was investigated. The stability of the particles was tested in HEPES buffer. The r2* relaxivity of protons and mass attenuation coefficient of the nanoparticles were determined. The particle diameter and surface morphology were studied after neutron activation. Results Spherical particles with a smooth surface and diameter of 78?±?10 nm were obtained, and the particles were stable in buffer. Neutron irradiation did not damage the particles, and adequate amounts of activity were produced for nuclear imaging and radioablation of malignancies through intratumoral injections. Conclusions The present study demonstrates that HoAcAc nanoparticles were prepared using a solvent evaporation process. The particle diameter can easily be adapted and can be optimized for specific therapeutic applications and tumor types. PMID:20680667

  20. Preparation and characterization of Ga2O3 and GaN nanoparticles

    NASA Astrophysics Data System (ADS)

    Rusu, E.; Ursaki, V.; Raevschi, S.; Vlazan, P.

    2015-02-01

    In this communication, we present results on preparation of GaN nanoparticles by conversion of Ga2O3 nanocrystals in a flow of NH3 and H2. The monoclinic Ga2O3 nanoparticles have been prepared by hydrothermal method with gallium nitrate and sodium hydroxide as precursors. Ga2O3 nanowires are produced with increasing the duration of the hydrothermal process up to 24 hours. The production of ?-phase Ga2O3 has been confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. According to XRD, Raman and FTIR spectra, wurtzite type GaN nanocrystals with an average size of 28.6 nm are obtained by nitridation of Ga2O3 nanoparticles. Doping of Ga2O3 nanomaterial with Eu3+ ions in the hydrothermal process is demonstrated, and the emission spectra of this Eu-doped nanomaterial are compared with those of Eu-doped nanoparticles prepared previously by solid state reactions.

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

    PubMed Central

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

    2014-01-01

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

  2. Well-crystallized barium titanate nanoparticles prepared by plasma chemical vapor deposition

    Microsoft Academic Search

    Keigo Suzuki; Kazunori Kijima

    2004-01-01

    Perovskite BaTiO3 nanoparticles were synthesized by the RF-plasma chemical vapor deposition method using Ba(DPM)2 and Ti(OiPr)4 as source materials. The suitable Ba\\/Ti molar ratio of reactants for preparing a single phase of BaTiO3 with a stoichiometric composition was experimentally confirmed to be about 1.2±0.1. The average particle size of BaTiO3 nanoparticles was measured to be 15.4 nm by transmission electron

  3. Preparation, characterization and antibacterial applications of ZnO-nanoparticles coated polyethylene films for food packaging.

    PubMed

    Tankhiwale, Rasika; Bajpai, S K

    2012-02-01

    The present work describes the preparation of ZnO nanoparticles loaded starch-coated polyethylene film. The presence of ZnO nanoparticles was confirmed by surface plasmon resonance (SPR), X-ray diffraction (XRD) studies and transmission electron microscopy (TEM). The ZnO loaded film was tested for its biocidal action against model bacteria Escherichia coli using zone inhibition and killing kinetics of bacterial growth methods. This newly developed material bears potential to be used as food packaging material to prevent food stuff from bacterial contamination. PMID:22015180

  4. Preparation and properties of amorphous titania-coated zinc oxide nanoparticles

    SciTech Connect

    Liao Minhung [Applied Science and Technology Research Center, Department of Cosmetology and Styling, Transworld Institute of Technology, Douliu 640, Yulin, Taiwan (China)]. E-mail: liaomh@mail.tit.edu.tw; Hsu, C.-H. [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China); Chen, D.-H. [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan 701 (China)]. E-mail: chendh@mail.ncku.edu.tw

    2006-07-15

    Amorphous TiO{sub 2}-coated ZnO nanoparticles were prepared by the solvothermal synthesis of ZnO nanoparticles in ethanol and the followed by sol-gel coating of TiO{sub 2} nanolayer. The analyses of X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed that the resultant ZnO nanoparticles were hexagonal with a wurtzite structure and a mean diameter of about 60 nm. Also, after TiO{sub 2} coating, the TEM images clearly indicated the darker ZnO nanoparticles being surrounded by the lighter amorphous TiO{sub 2} layers. The zeta potential analysis revealed the pH dependence of zeta potentials for ZnO nanoparticles shifted completely to that for TiO{sub 2} nanoparticles after TiO{sub 2} coating, confirming the formation of core-shell structure and suggesting the coating of TiO{sub 2} was achieved via the adhesion of the hydrolyzed species Ti-O{sup -} to the positively charged surface of ZnO nanoparticles. Furthermore, the analyses of Fourier transform infrared (FTIR) and Raman spectra were also conducted to confirm that amorphous TiO{sub 2} were indeed coated on the surface of ZnO nanoparticles. In addition, the analyses of ultraviolet-visible (UV-VIS) and photoluminescence (PL) spectra revealed that the absorbance of amorphous TiO{sub 2}-coated ZnO nanoparticles at 375 nm gradually decreased with an increase in the Ti/Zn molar ratio and the time for TiO{sub 2} coating, and the emission intensity of ZnO cores could be significantly enhanced by the amorphous TiO{sub 2} shell. - Graphical abstract: Amorphous titania-coated ZnO nanoparticles with a core-shell structure were prepared. It was found that the emission intensity of ZnO cores could be significantly enhanced by the amorphous TiO{sub 2} shell.

  5. Characterization and structural analysis of nano-sized Ba-Zn ferrite powders prepared by using a self-propagating high-temperature synthesis reaction and mechanical milling

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Seong, B. S.; Kim, S. S.

    2009-04-01

    Nano-sized Ba xZn 1-xFe 2O 4 ferrites were prepared by using a self-propagating high-temperature synthesis (SHS) reaction, followed by mechanical milling. The combustion temperature and the propagating rate during the SHS reaction were in the ranges of 860-1208 K and 4.9-6.0 mm/s, respectively. The final products were crystalline Ba 0.23Zn 0.77Fe 2O 4 and Ba 0.48Zn 0.52Fe 2O 4 phases with an average particle size of less than about 100 nm. As the initial composition ratio of BaO/ZnO and the oxygen partial pressure during the SHS reaction changed from 0.5 to 2.0 and 0.025 to 0.1, the maximum magnetization (Ms), residual magnetization (Mr) and coercive force (iHc) changed by about 233%, 372% and 82%, respectively. The complex permeability decreases with an increase of the frequency, and its real value ( ? r?) has a peak value at about 0.3 GHz. Neutron diffraction revealed that the changes of the magnetic properties and permeability were related to the non-stoichiometries of the ferrite powders.

  6. Magnetic properties of nanostructured MnZn ferrite

    Microsoft Academic Search

    Mohammad Javad Nasr Isfahani; Maxym Myndyk; Dirk Menzel; Armin Feldhoff; Jamshid Amighian; Vladimir Šepelák

    2009-01-01

    Mn0.5Zn0.5Fe2O4 nanoparticles (10–30nm) have been prepared via mechanochemical processing, using a mixture of two single-phase ferrites, MnFe2O4 and ZnFe2O4. SQUID measurements (field-cooled magnetization curves and hysteresis loops) were performed to follow the mechanically induced evolution of the MnFe2O4\\/ZnFe2O4 mixture submitted to the high-energy milling process. The resulting single MnZn nanoferrite phase was characterized by SQUID (M–H curve), Faraday balance (M–T

  7. 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. PMID:25819361

  8. Synthesis of nano-sized spherical barium-strontium ferrite particles

    Microsoft Academic Search

    S.-H. Gee; Y.-K. Hong; F. J. Jeffers; M.-H. Park; J. C. Sur; C. Weatherspoon; I. T. Nam

    2005-01-01

    Magnetic recording media requires good particle dispersion, a smooth surface, and small interparticle interaction to make an adequate signal-to-noise ratio (SNR). Well dispersed 50-60 nm sized spherical barium-strontium ferrite (S-Ba\\/Sr-Fe) nanoparticles were successfully prepared with 40 nm sized hematite precursor particles and BaCO3\\/SrCO3 colloid. The coercivity and saturation magnetizations of S-Ba\\/Sr-Fe nano-particles were 1568 Oe and 48.6 emu\\/g, respectively. In

  9. Preparation, characterization and application of pyrene-loaded methoxy poly(ethylene glycol)–poly(lactic acid) copolymer nanoparticles

    Microsoft Academic Search

    Yan Zhang; Qizhi Zhang; Liusheng Zha; Wuli Yang; Changchun Wang; Xinguo Jiang; Shoukuan Fu

    2004-01-01

    Pyrene-loaded biodegradable polymer nanoparticles were prepared by incorporating pyrene into the polymer nanoparticles formulated from amphiphilic diblock copolymer, methoxy poly(ethylene glycol)–poly(lactic acid) (MePEG–PLA). Their morphological structure and physical properties were characterized by nuclear magnetic resonance (NMR), dynamic light scattering, fluorescence spectroscopy, transmission electronic microscopy and zeta potential measurements. Further, MePEG–PLA nanoparticles containing pyrene as fluorescent marker were administered intranasally to

  10. DNA Biosensor Prepared by Electrodeposited Pt-nanoparticles for the Detection of Specific Deoxyribonucleic Acid Sequence in Genetically Modified Soybean

    Microsoft Academic Search

    Mao-Qing WANG; Xiao-Yan DU; li-Yan LIU; Qian SUN; Xian-Chen JIANG

    2008-01-01

    DNA biosensors were prepared by electrodepositing platinum nanoparticles (Pt-nano) on the surface of a glassy carbon electrode (GCE). A 19-mer ssDNA of promoter 35S, which was specific to most inserted sequences in genetically modified food, was immobilized on the Pt nanoparticle-deposited GC electrode. The morphology of the surface of Pt nanoparticle-deposited GC electrodes (Pt-nano\\/GCE) was investigated under a scanning electron

  11. Preparation of reactive surface-modified Ag nanoparticles and their assembly on a Si surface via covalent bonds

    Microsoft Academic Search

    Benfang He; Shengmao Zhang; Linna Zhang; Zhishen Wu; Zhijun Zhang

    2007-01-01

    Surface-modified Ag nanoparticles containing omega-functionalized reactive groups were prepared via the reduction of aqueous AgNO3 in the presence of a modifying agent, O,O'-di(10-undecene) dithiophosphinic acid (UDDPA). The resulting surface-modified Ag nanoparticles were assembled on the surface of hydrogen-terminated Si(111) by a thermal hydrosilylation reaction. The morphologies and structures of the Ag nanoparticles and their assembled film on the Si substrate

  12. Preparing a magnetically responsive single-wall carbon nanohorn colloid by anchoring magnetite nanoparticles.

    PubMed

    Utsumi, Shigenori; Urita, Koki; Kanoh, Hirofumi; Yudasaka, Masako; Suenaga, Kazutomo; Iijima, Sumio; Kaneko, Katsumi

    2006-04-13

    A single-wall carbon nanohorn (SWNH) colloid was made to be magnetically responsive by anchoring magnetite nanoparticles prepared by the homogeneous mixing of FeCl(2)-FeCl(3) and NaOH solutions. Transmission electron microscopy observation showed the high dispersion of magnetite particles of 2-9 nm on the surface of the SWNH colloid, coinciding with the broad X-ray diffraction peaks of the magnetites. The magnetization measurements showed that the magnetite nanoparticles-anchored SWNH (mag-SWNH) colloid has the hybrid property of ferrimagnetism and superparamagnetism. It was demonstrated that mag-SWNH colloid dispersed in water by sonication responded to an external magnetic field, gathering toward a magnet. N(2) adsorption experiments showed the high nanoporosity of mag-SWNHs and that magnetite nanoparticles were preferably anchored at "nanowindow" sites and the entrance sites of interstitial pores. This magnetically responsive SWNH colloid should contribute to the field of drug delivery. PMID:16599481

  13. Preparation of gold nanoparticles using Salicornia brachiata plant extract and evaluation of catalytic and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Ayaz Ahmed, Khan Behlol; Subramanian, Swetha; Sivasubramanian, Aravind; Veerappan, Ganapathy; Veerappan, Anbazhagan

    2014-09-01

    The current study deals with the synthesis of gold nanoparticles (AuNPs) using Salicornia brachiata (Sb) and evaluation of their antibacterial and catalytic activity. The SbAuNPs showed purple color with a characteristic surface plasmon resonance peak at 532 nm. Scanning electron microscopy and transmission electron microscopy revealed polydispersed AuNPs with the size range from 22 to 35 nm. Energy dispersive X-ray and thin layer X-ray diffraction analysis clearly shows that SbAuNPs was pure and crystalline in nature. As prepared gold nanoparticles was used as a catalyst for the sodium borohydride reduction of 4-nitro phenol to 4-amino phenol and methylene blue to leucomethylene blue. The green synthesized nanoparticles exhibited potent antibacterial activity against the pathogenic bacteria, as evidenced by their zone of inhibition. In addition, we showed that the SbAuNPs in combination with the regular antibiotic, ofloxacin, exhibit superior antibacterial activity than the individual.

  14. Organic/hybrid nanoparticles and single-walled carbon nanotubes: preparation methods and chiral applications.

    PubMed

    Alhassen, Haysem; Antony, Vijy; Ghanem, Ashraf; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Ostrikov, Kostya Ken

    2014-11-01

    Nanoparticles are molecular-sized solids with at least one dimension measuring between 1-100 nm or 10-1000 nm depending on the individual discipline's perspective. They are aggregates of anywhere from a few hundreds to tens of thousands of atoms which render them larger than molecules but smaller than bulk solids. Consequently, they frequently exhibit physical and chemical properties somewhere between. On the other hand, nanocrystals are a special class of nanoparticles which have started gaining attention recently owing to their unique crystalline structures which provide a larger surface area and promising applications including chiral separations. Hybrid nanoparticles are supported by the growing interest of chemists, physicists, and biologists, who are researching to fully exploit them. These materials can be defined as molecular or nano-composites with mixed (organic or bio) and inorganic components, where at least one of the component domain has a dimension ranging from a few Å to several nanometers. Similarly, and due to their extraordinary physical, chemical, and electrical properties, single-walled carbon nanotubes have been the subject of intense research. In this short review, the focus is mainly on the current well-established simple preparation techniques of chiral organic and hybrid nanoparticles as well as single-walled carbon nanotubes and their applications in separation science. Of particular interest, cinchonidine, chitosan, and ?-CD-modified gold nanoparticles (GNPs) are discussed as model examples for organic and hybrid nanoparticles. Likewise, the chemical vapor deposition method, used in the preparation of single-walled carbon nanotubes, is discussed. The enantioseparation applications of these model nanomaterials is also presented. PMID:24811353

  15. Preparation of Biosilica-enriched Filler and an Example of its Use in a Nano-Particle Retention System

    E-print Network

    Fleming, Paul D. "Dan"

    Preparation of Biosilica-enriched Filler and an Example of its Use in a Nano-Particle Retention. The positive effect of this filler in nano-particle retention system is demonstrated. INTRODUCTION Most contains less cellulose. Xylans are the principal hemicelluloses of hardwoods and straws, analytically

  16. Direct, rapid, facile photochemical method for preparing copper nanoparticles and copper patterns.

    PubMed

    Zhu, Xiaoqun; Wang, Bowen; Shi, Feng; Nie, Jun

    2012-10-01

    We develop a facile method for preparing copper nanoparticles and patterned surfaces with copper stripes by ultraviolet (UV) irradiation of a mixture solution containing a photoinitiator and a copper-amine coordination compound. The copper-amine compound is formed by adding diethanol amine to an ethanol solution of copper chloride. Under UV irradiation, free radicals are generated by photoinitiator decomposition. Meanwhile, the copper-amine coordination compound is rapidly reduced to copper particles because the formation of the copper-amine coordination compound prevents the production of insoluble cuprous chloride. Poly(vinylpyrrolidone) is used as a capping agent to prevent the aggregation of the as-prepared copper nanoparticles. The capping agent increases the dispersion of copper nanoparticles in the ethanol solution and affects their size and morphology. Increasing the concentration of the copper-amine coordination compound to 0.1 M directly forms a patterned surface with copper stripes on the transparent substrate. This patterned surface is formed through the combination of the heterogeneous nucleation of copper nanoparticles and photolithography. We also investigate the mechanism of photoreduction by UV-vis spectroscopy and gas chromatography-mass spectrometry. PMID:22974517

  17. Controllable preparation and properties of composite materials based on ceria nanoparticles and carbon nanotubes

    SciTech Connect

    Li Changqing; Sun Nijuan; Ni Jiangfeng; Wang Jinyong; Chu Haibin; Zhou Henghui; Li Meixian [Beijing National Laboratory for Molecular Sciences, National Laboratory of Rare Earth Material Chemistry and Application, Key Laboratory for the Physics and Chemistry of Nanodevices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Li Yan [Beijing National Laboratory for Molecular Sciences, National Laboratory of Rare Earth Material Chemistry and Application, Key Laboratory for the Physics and Chemistry of Nanodevices, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)], E-mail: yanli@pku.edu.cn

    2008-10-15

    We report a method to prepare composites based on carbon nanotubes (CNTs) and CeO{sub 2} nanoparticles (NPs). The CeO{sub 2} NPs were attached to CNTs by hydrothermal treatment of Ce(OH){sub 4}/CNT mixture in NaOH solution at 180 deg. C. It was found that larger CeO{sub 2} NPs were formed in the presence of CNTs. Grain size of CeO{sub 2} NPs in the composites can be reduced when NaNO{sub 3} was added in the hydrothermal process. Electrochemical characterizations have shown that the composites possess a specific capacity between those of CNTs and CNTs mechanically mixed with CeO{sub 2}. These CeO{sub 2}/CNT composites could serve as promising anode materials for Li-ion batteries. - Graphical abstract: Composites based on carbon nanotubes (CNTs) and CeO{sub 2} nanoparticles were prepared with a mild hydrothermal treatment. Larger CeO{sub 2} nanoparticles were formed in the presence of CNTs. Grain size of CeO{sub 2} nanoparticles in composites could be reduced when NaNO{sub 3} was added. The size modulation mechanism was discussed. This CeO{sub 2}/CNTs composites could serve as promising anode materials for Li-ion batteries.

  18. Role of copper on structural, magnetic and dielectric properties of nickel ferrite nano particles

    NASA Astrophysics Data System (ADS)

    Balavijayalakshmi, J.; Suriyanarayanan, N.; Jayaprakash, R.

    2015-07-01

    Copper doped nickel ferrites Ni(1-x)CuxFe2O4 (where x=0.2, 0.4, 0.6) nanoparticles are prepared by co-precipitation method and sintered at 600 °C. The XRD study confirms the formation of single-phase cubic spinel Ni-Cu ferrites. The particle size increases with Cu substitution. FT-IR spectra confirm the absorption bands around 554-547 cm-1 for the tetrahedral sites and around 448-450 cm-1 for the octahedral sites. The inclusion of copper shifts the tetrahedral band to lower values. The saturation magnetization (Ms) and remanent magnetization (Mr) decrease with increase in copper concentration and the coercivity (Hc) is found to increase for all the compositions sintered at 600 °C. The dielectric constant decreases drastically for all the compositions and reaches a constant value. These nanoparticles can be tested for humidity sensing applications.

  19. Preparation and Physicochemical Properties of 10-Hydroxycamptothecin (HCPT) Nanoparticles by Supercritical Antisolvent (SAS) Process

    PubMed Central

    Zhao, Xiuhua; Zu, Yuangang; Jiang, Ru; Wang, Ying; Li, Yong; Li, Qingyong; Zhao, Dongmei; Zu, Baishi; Zhang, Baoyou; Sun, Zhiqiang; Zhang, Xiaonan

    2011-01-01

    The goal of the present work was to study the feasibility of 10-hydroxycamptothecin (HCPT) nanoparticle preparation using supercritical antisolvent (SAS) precipitation. The influences of various experimental factors on the mean particle size (MPS) of HCPT nanoparticles were investigated. The optimum micronization conditions are determined as follows: HCPT solution concentration 0.5 mg/mL, the flow rate ratio of CO2 and HCPT solution 19.55, precipitation temperature 35 °C and precipitation pressure 20 MPa. Under the optimum conditions, HCPT nanoparticles with a MPS of 180 ± 20.3 nm were obtained. Moreover, the HCPT nanoparticles obtained were characterized by Scanning electron microscopy, Dynamic light scattering, Fourier-transform infrared spectroscopy, High performance liquid chromatography-mass spectrometry, X-ray diffraction and Differential scanning calorimetry analyses. The physicochemical characterization results showed that the SAS process had not induced degradation of HCPT. Finally, the dissolution rates of HCPT nanoparticles were investigated and the results proved that there is a significant increase in dissolution rate compared to unprocessed HCPT. PMID:21731466

  20. 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.

  1. Electrochemical preparation and characterization of polypyrrole/stainless steel electrodes decorated with gold nanoparticles.

    PubMed

    Gutiérrez Pineda, Eduart; Alcaide, Francisco; Rodríguez Presa, María J; Bolzán, Agustín E; Gervasi, Claudio A

    2015-02-01

    The electrosynthesis and characterization of polypyrrole(PPy)/stainless steel electrodes decorated with gold nanoparticles and the performance of the composite electrode for sensing applications is described. PPy films were grown in potassium perchlorate and sodium salicylate solutions under comparable electropolymerization conditions. Polymer films prepared in the presence of perchlorate ions exhibited worm-like structures, whereas columnar structures were obtained in salicylate-containing solutions. Voltammetric response of PPy films prepared in salicylate solutions was more reversible. PPy films were decorated with gold nanoparticles obtained by a double step potentiostatic electrodeposition routine that allowed fine control of deposit characteristics. Analysis of deposits was performed by means of SEM and confocal Raman spectroscopy. The electrocatalytic activity of the Au/PPy electrodes was assessed for the electro-oxidation of hydrazine and hydroxylamine. Results showed a successful optimization of the route of synthesis that rendered nanocomposite electrode materials with promising applications in electrochemical sensing. PMID:25569325

  2. Preparation and catalytic ability to reduce hydrogen peroxide of Ag nanoparticles highly dispersed via hyperbranched copolymer

    NASA Astrophysics Data System (ADS)

    Yao, Lu; Yang, Weiying; Yang, Jie; He, Linghao; Sun, Jing; Song, Rui; Ma, Zhi; Huang, Wei

    2011-03-01

    Highly dispersed Ag nanoparticles, stabilized by hyperbranched copolymers (HPCs), were prepared by chemical reduction in toluene. These Ag NPs were used further for the fabrication of a hydrogen peroxide (H2O2) sensor, by which a good catalytic ability for the reduction of H2O2 was found.Highly dispersed Ag nanoparticles, stabilized by hyperbranched copolymers (HPCs), were prepared by chemical reduction in toluene. These Ag NPs were used further for the fabrication of a hydrogen peroxide (H2O2) sensor, by which a good catalytic ability for the reduction of H2O2 was found. Electronic supplementary information (ESI) available: Structure and structure parameters of the HPCs, and UV-vis and XPS spectra of the NPs . See DOI: 10.1039/c0nr00567c

  3. Facile preparation of silver nanoparticle films as an efficient surface-enhanced Raman scattering substrate

    NASA Astrophysics Data System (ADS)

    Sun, Yujing; Zhang, Yue; Shi, Yan; Xiao, Xianping; Dai, Haichao; Hu, Jingting; Ni, Pengjuan; Li, Zhuang

    2013-10-01

    Here, we report a new and facile method to prepare silver nanoparticles (Ag NPs) film for surface-enhanced Raman scattering (SERS)-based sensing. The porous Ni foam was used as a template to generate high quality of Ag NPs by seed-mediated growth of metallic nanoparticles. The preparation process is very economic and environment-friendly, can achieve the recovery of the raw materials. We found that the type of silver-plating solution and the growth time are two key factors to determine the magnitude of SERS signal enhancement. Using rhodamine 6G (R6G) and 4-animothiophenol (4-ATP) as probe molecules, the created Ag NP films exhibited relatively high enhancement ability, good stability, and well reproducibility. The synthesized SERS-active substrate was further used to detect melamine molecules, an illegal additive in infant milk powder, and the limitation of detection can reach 1 ?M.

  4. Nanoencapsulation I. Methods for preparation of drug-loaded polymeric nanoparticles.

    PubMed

    Pinto Reis, Catarina; Neufeld, Ronald J; Ribeiro, António J; Veiga, Francisco

    2006-03-01

    Polymeric nanoparticles have been extensively studied as particulate carriers in the pharmaceutical and medical fields, because they show promise as drug delivery systems as a result of their controlled- and sustained-release properties, subcellular size, and biocompatibility with tissue and cells. Several methods to prepare nanoparticles have been developed during the last two decades, classified according to whether the particle formation involves a polymerization reaction or arises from a macromolecule or preformed polymer. In this review the most important preparation methods are described, especially those that make use of natural polymers. Advantages and disadvantages will be presented so as to facilitate selection of an appropriate nanoencapsulation method according to a particular application. PMID:17292111

  5. Preparation and Characterization of Gelatin Nanofibers Containing Silver Nanoparticles

    PubMed Central

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO3)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO3/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO3 and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO3. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  6. Preparation and characterization of gelatin nanofibers containing silver nanoparticles.

    PubMed

    Jeong, Lim; Park, Won Ho

    2014-01-01

    Ag nanoparticles (NPs) were synthesized in formic acid aqueous solutions through chemical reduction. Formic acid was used for a reducing agent of Ag precursor and solvent of gelatin. Silver acetate, silver tetrafluoroborate, silver nitrate, and silver phosphate were used as Ag precursors. Ag+ ions were reduced into Ag NPs by formic acid. The formation of Ag NPs was characterized by a UV-Vis spectrophotometer. Ag NPs were quickly generated within a few minutes in silver nitrate (AgNO?)/formic acid solution. As the water content of formic acid aqueous solution increased, more Ag NPs were generated, at a higher rate and with greater size. When gelatin was added to the AgNO?/formic acid solution, the Ag NPs were stabilized, resulting in smaller particles. Moreover, gelatin limits further aggregation of Ag NPs, which were effectively dispersed in solution. The amount of Ag NPs formed increased with increasing concentration of AgNO? and aging time. Gelatin nanofibers containing Ag NPs were fabricated by electrospinning. The average diameters of gelatin nanofibers were 166.52 ± 32.72 nm, but these decreased with the addition of AgNO?. The average diameters of the Ag NPs in gelatin nanofibers ranged between 13 and 25 nm, which was confirmed by transmission electron microscopy (TEM). PMID:24758929

  7. Preparation of PLGA nanoparticles using TPGS in the spontaneous emulsification solvent diffusion method

    Microsoft Academic Search

    Farnaz Esmaeili; Fatemeh Atyabi; Rassoul Dinarvand

    2007-01-01

    D-alpha-tocopheryl poly (ethylene glycol) 1000 succinate (TPGS) is a widely used form of vitamin E that has been used as a solubilizer, an emulsifier and as a vehicle for drug delivery formulations. In this study, poly lactide-co-glycolide (PLGA) nanoparticles were prepared by spontaneous emulsification solvent diffusion (SESD) method. TPGS as an emulsifier and further as a matrix material blended with

  8. Preparation of carbon nanotubes supported platinum nanoparticles by an organic colloidal process for nonenzymatic glucose sensing

    Microsoft Academic Search

    Li-Hua Li; Wei-De Zhang

    2008-01-01

    Multi-walled carbon nanotubes (MWNTs) supported platinum nanoparticles with narrow size distribution were prepared by an organic\\u000a colloidal process with sodium citrate as the coordination reagent and stabilizer, and ethylene glycol as the reduction reagent.\\u000a A nonenzymatic glucose sensor with high sensitivity based on the Pt\\/MWNTs electrode was demonstrated. Transmission electron\\u000a microscopy (TEM) and X-ray diffraction (XRD) were employed to investigate

  9. Facile route for preparation of silver nanoparticle-coated precipitated silica

    Microsoft Academic Search

    Dang Viet Quang; Pradip B. Sarawade; Askwar Hilonga; Sung Dae Park; Jong-Kil Kim; Hee Taik Kim

    2011-01-01

    In this research, a facile route was used to prepare silver nanoparticle-coated precipitated silica using sodium silicate, a cheap precursor. Precipitated silica (PS) was synthesized by dropping 8% H2SO4 into a mixed solution of sodium silicate 24% (Na2O·3.4SiO2) and NaCl 4%; under constant stirring. The precipitated silica was then modified by simultaneous addition of 3-aminopropyltriethoxysilane (3-APTES) and 8% H2SO4. The

  10. Preparation of silver nanoparticle containing silica micro beads and investigation of their antibacterial activity

    Microsoft Academic Search

    Dang Viet Quang; Pradip B. Sarawade; Askwar Hilonga; Jong-Kil Kim; Young Gyu Chai; Sang Hoon Kim; Jae-Yong Ryu; Hee Taik Kim

    2011-01-01

    Silver nanoparticle containing silica micro beads (Ag-NPBs) were successfully prepared by using sodium silicate, a cheap precursor, involving chemical reductive method. First, silica gel was synthesized and crushed into micro beads which have sizes ranging from 0.5 to 1mm. Silica micro beads were then modified with 3-aminopropyltriethoxysilane to graft amino functional groups onto their surface. Silver ions were loaded onto

  11. Morphology and microstructure investigations of YB66 nano-particles prepared by plasma chemical process

    Microsoft Academic Search

    J. Y. Huang; T. Ishigaki; T. Tanaka; S. Horiuchi

    1998-01-01

    Nanocrystalline particles of YB66 were prepared by plasma chemical process, using starting powders of YB4 and B, and the morphology was examined by high-resolution transmission electron microscopy (HRTEM). The average grain size of the YB66 particles is less than 100 nm. All the YB66 nano-particles are cubic in shape, suggesting that they have been formed through a direct coagulation from

  12. Preparation of luminescent silicon nanoparticles by photothermal aerosol synthesis followed by acid etching

    Microsoft Academic Search

    X. Li; Y. He; S. S. Talukdar; M. T. Swihart

    2004-01-01

    CO2 laser-induced pyrolysis of silane (photothermal aerosol synthesis) was used to produce Si nanoparticles. Particles with an average diameter as small as 5?nm were prepared directly from silane in the gas phase. Etching these particles with mixtures of hydrofluoric acid (HF) and nitric acid (HNO3) is shown to be an effective method to reduce the size of the particles produced

  13. Paclitaxel-loaded PLGA nanoparticles: preparation, physicochemical characterization and in vitro anti-tumoral activity

    Microsoft Academic Search

    Cristina Fonseca; Sérgio Simões; Rogério Gaspar

    2002-01-01

    The main objective of this study was to develop a polymeric drug delivery system for paclitaxel, intended to be intravenously administered, capable of improving the therapeutic index of the drug and devoid of the adverse effects of Cremophor® EL. To achieve this goal paclitaxel (Ptx)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (Ptx-PLGA-Nps) were prepared by the interfacial deposition method. The influence of

  14. Preparation of zinc oxide nanoparticles coated with homogeneous Al 2O 3 layer

    Microsoft Academic Search

    Fangli Yuan; Hu Peng; Ye Yin; Yin Chunlei; Hojin Ryu

    2005-01-01

    Zinc oxide nanoparticles coated with Al2O3 were prepared by calcining basic carbonate of zinc (BCZ) powders coated with Al(OH)3 precipitation at 400–600°C. Al(OH)3 was coated on the surface of BCZ powders which are precursor for ZnO, in stead of calcined ZnO particles. The size and shape of BCZ powders are different after coating with Al2O3, as a result, ZnO particles

  15. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS

    SciTech Connect

    Seetala V. Naidu; Upali Siriwardane; Akundi N. Murty

    2004-02-23

    The preparation of Cu, Co, Fe, Cu/Co, Cu/Fe and Co/Fe nano-particle metal loaded mesoporous 1 mm spherical granular {gamma}-Al{sub 2}O{sub 3} catalysts, by combined sol-gel/oil-drop methods followed by calcination and hydrogenation steps, is accomplished. Parameters for calcination process were optimized using DTA. The properties of metal loaded {gamma}-Al{sub 2}O{sub 3} granules were compared for the preparations starting with two precursors: aluminum tri-sec-butoxide (ALTSB) and aluminum tri-iso-propoxide (ALTIP). Three sol-gel/oil-drop catalyst preparation methods; (1) Metal nitrate solutions co-entrapped-sol-gel (2) nano-particle metal oxide co-entrapped-sol-gel, and (3) Metal impregnation on preformed alumina granules, were used. Structure and composition of metal-loaded-granules were investigated using XRD, SEM, EDX, and surface area measurements (BET method). The nano-particle nature of catalysts was confirmed using SEM and X-ray diffraction. The reduction efficiency of hydrogenation of catalysts was examined by magnetic studies using a vibrating sample magnetometer (VSM). Catalysts could be effectively calcined at 450 C and the surface area values obtained were between 200-350 m{sup 2}/g, indicating the mesoporous nature of catalyst support. Parameters affecting the metal loading process were also studied, and the optimum conditions were identified and reported for reproducible synthesis of the metal loaded {gamma}-alumina granular particles. The catalyst activities of Fe, Co, and Co/Fe on alumina for the conversion of CO/H{sub 2} and CO{sub 2}/H{sub 2} mixtures were investigated using Gas chromatography (GC) with N{sub 2} as a standard carrier gas. Both, slurry-phase-batch and gas-phase-continuous-flow, reactors were used. Magnetization studies on reduced, CO/H{sub 2} post-reaction catalyst in both gas and slurry phase were performed using vibrating sample magnetometer (VSM). Magnetic studies of post-reaction Co and Fe nano-catalysts showed that the formation of carbides is higher for iron compared to cobalt. In the Fe/Co mixed catalyst, it is observed that the presence of iron enhances the cobalt oxide reduction. Catalyst with mixed metal Fe/Co compositions at 12% nitrate solutions (prepared by sol-gel/oil-drop) showed the best conversion rates for the syngas (CO+H{sub 2}). Nano-particle catalysts on sol-gel prepared mesoporous {gamma}-alumina (particularly the nano-particle metal oxide co-entrapped-sol-gel) showed higher conversion rates compared to conventional catalysts prepared by coprecipitation methods.

  16. Preparation of hydroxyapatite nanoparticles by sol-gel method with optimum processing parameters

    NASA Astrophysics Data System (ADS)

    Yusoff, Yusriha Mohd; Salimi, Midhat Nabil Ahmad; Anuar, Adilah

    2015-05-01

    Many studies have been carried out in order to prepare hydroxyapatite (HAp) by various methods. In this study, we focused on the preparation of HAp nanoparticles by using sol-gel technique in which few parameters are optimized which were stirring rate, aging time and sintering temperature. HAp nanoparticles were prepared by using precursors of calcium nitrate tetrahydrate, Ca(NO3)2.4H2O and phosphorous pentoxide, P2O5. Both precursors are mixed in ethanol respectively before they were mixed together in which it formed a stable sol. Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) were used for its characterization in terms of functional group, phase composition, crystallite size and morphology of the nanoparticles produced. FTIR spectra showed that the functional groups that present in all five samples were corresponding to the formation of HAp. Besides, XRD shows that only one phase was formed which was hydroxyapatite. Meanwhile, SEM shows that the small particles combine together to form agglomeration.

  17. Effect of preparation parameters on ultra low molecular weight chitosan/hyaluronic acid nanoparticles.

    PubMed

    Nazeri, Niloofar; Avadi, Mohammad Reza; Faramarzi, Mohammad Ali; Safarian, Shahrokh; Tavoosidana, Gholamreza; Khoshayand, Mohammad Reza; Amani, Amir

    2013-11-01

    Nanoparticles of ultra low molecular weight chitosan (ULMWCS)/hyaluronic acid (HA) were prepared by ion gelation. Three independent variables, namely, ratio of concentration of ULMWCS to HA (CS/HA), pH of solution and stirring time were studied to identify their effects on size, polydispersity and zeta potential of prepared nanoparticles using a Box-Behnken design. Results showed that pH and CS/HA have a direct effect on size, while increase of stirring time decreases the size of nanoparticles. Additionally, it was shown that all the independent parameters have direct effects on zeta potential. Also, the minimum polydispersity index was observed at lowest values of CS/HA. The model also predicted that the optimum values are 4.15, 4.14 and 180 (min) for the CS/HA, solution pH and stirring time, respectively. The obtained preparation had a size of 200 nm, polydispersity index of 0.37, and zeta potential of 13.0 mV. PMID:24099942

  18. Preparation of platinum nanoparticle and its catalytic activity for toluene oxidation.

    PubMed

    Kim, Sang Chai; Shim, Wang Geun; Lee, Man Seung; Jung, Sang Chul; Park, Young-Kwon

    2011-08-01

    Colloidal Pt nanoparticles are prepared using H2PtCl6 as a precursor, polyvinylpyrrolidone (PVP: molecular weight = 10,000 and 40,000) and hydrogen as a stabilizing agent and a reducing agent, respectively. The amounts of the precursor and the stabilizing agent and the molecular weight of PVP have an effect on the formation of Pt nanoparticles. Supported Pt catalyst (CSPt) is prepared from colloidal Pt nanoparticles and y-Al2O3. Another supported Pt catalyst (ISPt) is prepared by using the conventional incipient wetness impregnation method with an aqueous H2PtCl6 solution and gamma-Al2O3. The catalytic activities of CSPt and ISPt catalysts are compared for VOC (toluene) oxidation. Transmission Electron Microscopy (TEM), UV-vis, X-ray diffraction (XRD) and temperature programmed reduction (TPR) are used to characterize CSPt and ISPt catalysts. The experimental results reveal that the catalytic activity of CSPt is superior to that of ISPT. PMID:22103193

  19. Solution-combusting preparation of mono-dispersed Mn3O4 nanoparticles for electrochemical applications

    NASA Astrophysics Data System (ADS)

    Gao, Weiwei; Ye, Shiyong; Shao, Mingwang

    2011-09-01

    Manganese oxide (Mn3O4) nanoparticles with average diameter of 15 nm were prepared using alcohol solution of manganese chloride as starting material via a facile solution-combusting method. The flame core zone was chosen to prepare mono-dispersed and high crystalline products, which were employed to modify glassy carbon electrode and detect dopamine via cyclic voltammetry. The results exhibited excellent electrochemical sensitivity. A linear relationship between the concentration of dopamine and its oxidation peak current was obtained by differential pulse voltammetry, which will find wide application in the biological detection.

  20. Rietveld structure refinement of the cation distribution in ferrite fine particles studied by X-ray powder diffraction

    Microsoft Academic Search

    J. A. Gomes; M. H. Sousa; F. A. Tourinho; J. Mestnik-Filho; R. Itri; J. Depeyrot

    2005-01-01

    Samples of ZnFe2O4 and CuFe2O4 fine particles prepared by coprecipitation method have been studied by X-ray powder diffraction at room temperature. The oxygen position, the lattice parameter, the mean size of the nanoparticles and the cation distribution have been determined by means of Rietveld analysis, indicating the existence of mixed ferrites in both samples. These results are also evidenced through

  1. Electromagnetic properties of samarium-substituted NiCuZn ferrite prepared by auto-combustion method

    NASA Astrophysics Data System (ADS)

    Roy, P. K.; Bera, J.

    2009-02-01

    Ni 0.25Cu 0.2Zn 0.55Sm xFe 2-xO 4 ferrite with x=0.00, 0.025, 0.05 and 0.075 compositions were synthesized through the nitrate-citrate auto-combustion method. These powders were calcined, compacted and sintered at 900 °C for 4 h. Effect of Sm substitution on phase composition, microstructure and relative density were studied. Permeability, magnetic loss and AC resistivity were measured in the frequency range of 1 kHz-10 MHz. Permeability and AC resistivity were found to increase and loss decreased with Sm substitution up to x=0.05. Saturation magnetization also increased up to that substitution limit. Observed variations in electromagnetic properties have been explained.

  2. Facilely preparation and microwave absorption properties of Fe{sub 3}O{sub 4} nanoparticles

    SciTech Connect

    Wang, Guiqin, E-mail: wanggq@dlut.edu.cn [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Chang, Yongfeng; Wang, Lifang; Liu, Lidong; Liu, Chao [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China)

    2013-03-15

    Highlights: ? A bran-new method is firstly used to fabricate Fe{sub 3}O{sub 4} nanoparticles. ? The detailed analysis of formation mechanism is discussed. ? The electromagnetic absorption properties are defined. ? The effect of nanometer-sized is considered for the excellent microwave absorption. - Abstract: The Fe{sub 3}O{sub 4} nanoparticles were prepared by a novel wet-chemical method which shows its highly synthesizing efficiency and controllability. A possible formation mechanism was also proposed to explain the synthesizing process. X-ray diffraction (XRD) and transmission electron microscope (TEM) were employed and yielded an examination of an average diameter of 77 nm of the as-synthesized Fe{sub 3}O{sub 4} nanoparticles with face-centered cubic structure. Vibrating sample magnetometer (VSM) and vector network analyzer were employed to measure the magnetic property and electromagnetic parameters of the nanoparticles, then reflection losses (RL (dB)) were calculated in the frequency range of 2–18 GHz. A large saturation magnetization (72.36 emu/g) and high coercivity (95 Oe) were determined and indicated that the Fe{sub 3}O{sub 4} nanoparticles own strong magnetic performance. Following simulation results showed that the lowest reflection loss of the sample was ?21.2 dB at 5.6 GHz with layer thickness of 6 mm. Effect of nanometer-sized further provided an explanation for the excellent microwave absorption behavior shown by the Fe{sub 3}O{sub 4} nanoparticles.

  3. Pegylated poly(lactide) and poly(lactide-co-glycolide) nanoparticles: preparation, properties and possible applications in drug delivery.

    PubMed

    Avgoustakis, Konstantinos

    2004-10-01

    The preparation, properties and potential applications in drug delivery of biocompatible and biodegradable PLA-PEG and PLGA-PEG nanoparticles are discussed. PLA-PEG and PLGA-PEG nanoparticles have been produced by emulsification-solvent evaporation, solvent displacement and salting out methods. The nanoparticles can be stored as freeze-dried powders, but an adequate amount of a suitable lyoprotectant should be added prior lyophilisation to prevent nanoparticle aggregation and retain nanoparticle redispersibility. The nanoparticles have a core-shell structure with a PLA core and a PEG coating. Their basic colloidal properties and degradation depend on copolymer composition. The PLA-PEG and PLGA-PEG nanoparticles exhibit prolonged blood circulation following intravenous administration to animals. The composition of the nanoparticles determine their biodistribution properties, probably through its effects on the effectiveness of the PEG steric barrier and the size of the nanoparticles. The ability of the PLA-PEG and PLGA-PEG nanoparticles to evade rapid phagocytocis has extended the range of sites within the body that the nanoparticles can reach, which has significant implications with regard to their application in controlled drug delivery and targeting. The PLA-PEG and PLGA-PEG nanoparticles can be loaded with a variety of bioactive agents achieving satisfactory loading, especially in the case of hydrophobic drugs. The nanoparticles have been investigated for the treatment of infectious diseases and cancer, the intravenous and mucosal delivery of proteins, and oligonucleotide and gene delivery. The results have been encouraging and PLA-PEG and PLGA-PEG nanoparticle formulations, improving the therapeutic potential of both established and new drugs, may be expected to be available in the near future. PMID:16305394

  4. High frequency AC response, DC resistivity and magnetic studies of holmium substituted Ni-ferrite: A novel electromagnetic material

    NASA Astrophysics Data System (ADS)

    Pervaiz, Erum; Gul, I. H.

    2014-01-01

    Nanoparticles of holmium substituted nickel ferrites (NiHoxFe2-xO4) with x ranging from 0.0 to 0.15 have been prepared by the sol-gel auto-combustion method. Structural and morphology studies have been performed by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). XRD patterns revealed the formation of pure spinel phase ferrites without any impurity phase. Lattice parameter increases along with a decrease in crystallite size with increasing the concentration of Ho3+ in the parent nickel ferrite due to large ionic radius of Ho3+ (0.901 Å) as compared to Fe3+ (0.67 Å). SEM shows the spherical, uniformly distributed homogenous nanoparticles grown by controlled reaction parameters of the sol-gel method. Complex permittivity (?*) and complex electric modulus (M*) have been studied for the present nanoferrites in the frequency ranges of 1 MHz-1 GHz. Frequency dependent dielectric parameters (relative permittivity (?'), dielectric loss (??), dielectric loss tangent (tan ?)) decreases due to holmium substitution in nickel ferrites, showing the electrical conduction is decreasing in the nickel holmium ferrites with increase in the concentration of holmium. Complex modulus plots shows the poorly resolved semi circles and relaxation of nanoferrite is studied in the high frequency region. Also the relaxation time increases due to increase in x (0.0-0.15). DC electrical resistivity increases (107 ?-cm-1010 ?-cm) due to holmium ions substitution in nickel ferrites. Magnetic behavior was also characterized using a Vibrating Sample Magnetometer (VSM) under an applied magnetic field of 10 kOe and shows that magnetization decreases with increase in composition of holmium in nickel ferrites. High frequency behavior, low losses and very high DC electrical resistivity made the material a novel one for electromagnetic devices.

  5. Preparation and Characterization of Rifampin Loaded Mesoporous Silica Nanoparticles as a Potential System for Pulmonary Drug Delivery

    PubMed Central

    Mohseni, Meysam; Gilani, Kambiz; Mortazavi, Seyed Alireza

    2015-01-01

    The goal of this research is to determine the feasibility of loading rifampin into mesoporous silica nanoparticles. Rifampin was selected as a model lipophilic molecule since it is a well-documented and much used anti tuberculosis drug. The mesoporous silica nanoparticles were prepared by using tetraethyl ortho silicate and cetyltrimethyl ammonium bromide (as surfactant). The prepared nanoparticles were characterized in terms of their particle size measurement and porosimetry. The results showed that the particle size is 218 ± 46 nm (mean ± SD) and surface area is 816 m2g-1. In order to load rifampin within the mesopores, adsorption experiments using three different solvents (methanol, water and dimethyl sulfoxide) were carried out. The loading procedure resulted in a significant improvement in the amount of rifampin loaded into mesoporous silica nanoparticles and methanol was found to be a suitable solvent, providing a drug entrapment efficiency of 52 %. Rifampin loaded nanoparticles underwent different in-vitro tests including, SEM and drug release. The in-vitro drug release was investigated using buffer phosphate (pH=7.4). Regarding the drug release study, a biphasic pattern of release was observed. The drug-loaded mesoporous silica nanoparticles were capable of releasing 95% of their drug content after 24 h, following a faster release in the first four hours. The prepared rifampin loaded nanoparticles seem to have potential for use as a pulmonary drug delivery. PMID:25561909

  6. Preparation, characterization, and transport of dexamethasone-loaded polymeric nanoparticles across a human placental in vitro model

    PubMed Central

    Ali, Hazem; Kalashnikova, Irina; White, Mark Andrew; Sherman, Michael; Rytting, Erik

    2013-01-01

    The purpose of this study was to prepare dexamethasone-loaded polymeric nanoparticles and evaluate their potential for transport across human placenta. Statistical modeling and factorial design was applied to investigate the influence of process parameters on the following nanoparticle characteristics: particle size, polydispersity index, zeta potential, and drug encapsulation efficiency. Dexamethasone and nanoparticle transport was subsequently investigated using the BeWo b30 cell line, an in vitro model of human placental trophoblast cells, which represent the rate-limiting barrier for maternal-fetal transfer. Encapsulation efficiency and drug transport were determined using a validated high performance liquid chromatography method. Nanoparticle morphology and drug encapsulation were further characterized by cryo-transmission electron microscopy and X-ray diffraction, respectively. Nanoparticles prepared from poly(lactic-co-glycolic acid) were spherical, with particle sizes ranging from 140–298 nm, and encapsulation efficiency ranging from 52–89%. Nanoencapsulation enhanced the apparent permeability of dexamethasone from the maternal compartment to the fetal compartment more than 10-fold in this model. Particle size was shown to be inversely correlated with drug and nanoparticle permeability, as confirmed with fluorescently-labeled nanoparticles. These results highlight the feasibility of designing nanoparticles capable of delivering medication to the fetus, in particular, potential dexamethasone therapy for the prenatal treatment of congenital adrenal hyperplasia. PMID:23850397

  7. Characterization and magnetic properties of Sm- and Gd-substituted CoFe{sub 2}O{sub 4} nanoparticles prepared by forced hydrolysis in polyol

    SciTech Connect

    Tahar, L. Ben; Smiri, L.S. [Unite de Recherche 99/UR12-30, Faculte des Sciences de Bizerte, 7021 Jarzouna (Tunisia); Artus, M.; Joudrier, A.-L.; Herbst, F.; Vaulay, M.J. [ITODYS, Universite Paris 7, UMR-CNRS 7086, 2 place Jussieu, 75251 Paris (France); Ammar, S. [ITODYS, Universite Paris 7, UMR-CNRS 7086, 2 place Jussieu, 75251 Paris (France)], E-mail: ammarmer@ccr.jussieu.fr; Fievet, F. [ITODYS, Universite Paris 7, UMR-CNRS 7086, 2 place Jussieu, 75251 Paris (France)

    2007-11-06

    Pure nanoparticles of the CoFe{sub 2-x}RE{sub x}O{sub 4} (RE = Gd, Sm; x = 0.0, 0.1) system have been prepared by forced hydrolysis in polyol. The insertion of Sm{sup 3+} and Gd{sup 3+} cations into the cobalt ferrite structure has been investigated. X-ray micro-analysis (EDX) shows that the RE contents are close to the nominal ones. X-ray diffraction (XRD) evidences a cell size increase with slight distortions in the spinel-like lattice indicating the entrance of RE{sup 3+} ions. Micro-Raman spectroscopy confirms the cubic inverse-spinel structure and rules out the existence of impurities like hematite. Magnetic measurements (SQUID) show important differences in the magnetic properties of the unsubstituted and substituted particles. All the particles are superparamagnetic at room temperature and ferrimagnetic at low temperature. However, their main magnetic characteristics appear to be directly dependent on the RE content.

  8. Jingle-bell-shaped ferrite hollow sphere with a noble metal core: Simple synthesis and their magnetic and antibacterial properties

    SciTech Connect

    Li Siheng [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China); Wang Enbo [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China)], E-mail: Wangeb889@nenu.edu.cn; Tian Chungui; Mao Baodong; Kang Zhenhui; Li Qiuyu; Sun Guoying [Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024 (China)

    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.

  9. Photochemical preparation of rectangular PbSe and CdSe nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhao, Wen-Bo; Zhu, Jun-Jie; Chen, Hong-Yuan

    2003-05-01

    Rectangular lead selenide and cadmium selenide nanoparticles have been successfully prepared by a photochemical method from an aqueous solution of lead acetate, cadmium chlorate, and sodium selenosulfate in the presence of complexating agents of nitrilotriacetic acid at room temperature. It was found that the effects of the photonic intensity, the pH of the solution, and the species of complexating agents played important roles on the morphology control of the PbSe and CdSe nanoparticles. The products were characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectra, and photoluminescence spectrum. The mechanism for the formation of the PbSe and CdSe was discussed.

  10. Surface engineered nanoparticles for improved surface enhanced Raman scattering applications and method for preparing same

    DOEpatents

    Simmons, Blake A. (San Francisco, CA); Talin, Albert Alec (Livermore, CA)

    2009-11-27

    A method for producing metal nanoparticles that when associated with an analyte material will generate an amplified SERS spectrum when the analyte material is illuminated by a light source and a spectrum is recorded. The method for preparing the metal nanoparticles comprises the steps of (i) forming a water-in-oil microemulsion comprising a bulk oil phase, a dilute water phase, and one or more surfactants, wherein the water phase comprises a transition metal ion; (ii) adding an aqueous solution comprising a mild reducing agent to the water-in-oil microemulsion; (iii) stirring the water-in-oil microemulsion and aqueous solution to initiate a reduction reaction resulting in the formation of a fine precipitate dispersed in the water-in-oil microemulsion; and (iv) separating the precipitate from the water-in-oil microemulsion.

  11. Study on the interaction between bovine serum albumin and starch nanoparticles prepared by isoamylolysis and recrystallization.

    PubMed

    Ji, Na; Qiu, Chao; Li, Xiaojing; Xiong, Liu; Sun, Qingjie

    2015-04-01

    The current study primarily investigated the interaction of bovine serum albumin (BSA) with starch nanoparticles (SNPs) prepared by isoamylolysis and recrystallization using UV-vis, fluorescence, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and circular dichroism (CD). The enhanced absorbance observed by UV-vis spectroscopy and decreased intensity of fluorescence spectroscopy suggested that BSA could bind to SNPs and form a BSA-SNP complex. The synchronous fluorescence spectra revealed that the emission maximum of Tyr residue (at ??=15nm) was red-shifted at the investigated concentrations range, indicating that the conformation of BSA was changed. Quenching parameters showed that the quenching effect of SNPs was static quenching. TEM images showed that the SNPs were surrounded by protein coronae, indicating that nanoparticle-protein complexes had formed. The FTIR and CD characterization indicated that the SNPs induced structural changes in the secondary structure of BSA. PMID:25805153

  12. Third-order nonlinear optical response of colloidal gold nanoparticles prepared by sputtering deposition

    NASA Astrophysics Data System (ADS)

    Castro, Hemerson P. S.; Wender, Heberton; Alencar, Márcio A. R. C.; Teixeira, Sergio R.; Dupont, Jairton; Hickmann, Jandir M.

    2013-11-01

    The nonlinear optical responses of gold nanoparticles dispersed in castor oil produced by sputtering deposition were investigated, using the thermally managed Z-scan technique. Particles with spherical shape and 2.6 nm of average diameter were obtained and characterized by transmission electron microscopy and small angle X-ray scattering. This colloid was highly stable, without the presence of chemical impurities, neither stabilizers. It was observed that this system presents a large refractive third-order nonlinear response and a negligible nonlinear absorption. Moreover, the evaluation of the all-optical switching figures of merit demonstrated that the colloidal nanoparticles prepared by sputtering deposition have a good potential for the development of ultrafast photonic devices.

  13. Biomimetic glycopolymers tethered gold nanoparticles: preparation, self-assembly and lectin recognition properties.

    PubMed

    Pei, Danfeng; Li, Yanchun; Huang, Qingrong; Ren, Qu; Li, Fan; Shi, Tongfei

    2015-02-01

    Biomimetic glycopolymers poly(gluconamidoethylmethacrylate)-b-poly(?-caprolactone)-b-poly(gluconamidoethylmethacrylate) with degradable disulfide groups in the backbone (PGAMA-PCL-SS-PCL-PGAMA) were synthesized by the combination of ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP). The internal disulfide bonds were cleaved by reduction with dl-dithiothreitol to yield the corresponding thiol terminated glycopolymers. The thiol terminated glycopolymers were effectively anchored on the surface of gold nanoparticles to prepare the biomimetic glycopolymers modified gold nanoparticles (Gly@Au NPs). Moreover, the properties of the Gly@Au NPs in aqueous solution were investigated. Transmission electron microscopy (TEM) analysis revealed that the self-assembly morphology of the Gly@Au NPs can be fine-tuned, from irregular clusters to spherical aggregates, by changing the weight fraction of the hydrophobic PCL block. Furthermore, the Gly@Au NPs had specific recognition with Concanavalin A (Con A). PMID:25533190

  14. Preparation and Characterization of Selenium Incorporated Guar Gum Nanoparticle and Its Interaction with H9c2 Cells

    PubMed Central

    Soumya, Rema Sreenivasan; Vineetha, Vadavanath Prabhakaran; Reshma, Premachandran Latha; Raghu, Kozhiparambil Gopalan

    2013-01-01

    This study deals with the preparation and characterization of selenium incorporated guar gum nanoparticle (SGG), and its effect on H9c2 cardiomyoblast. Herein, nanoprecipitation techniques had been employed for the preparation of SGG nanoparticle. The prepared nanoparticle had been subjected to various types of analytical techniques like transmission electron microscopy (TEM), X-ray diffraction (XRD) and particle size analysis to confirm the characteristics of nanoparticle as well as for selenium incorporation. Physical characterization of nanoparticle showed that the size of nanoparticles increase upto ?69–173 nm upon selenium incorporation from ?41–132 nm. Then the prepared nanoparticles were evaluated for its effect on H9c2 cells. In this regard, the effect of nanoparticle on various vital parameters of H9c2 cells was studied. Parameters like cell viability, uptake of selenium incorporated guar gum nanoparticle by the cells, effect of SGG on DNA integrity, apoptosis, reactive oxygen species generation, alteration in transmembrane potential of mitochondria and cytoskeletal integrity had been investigated. Viability results showed that up to 25 nM of SGG was safe (10.31%) but beyond that it induces cytotoxicity. Cellular uptake of selenium showed that cell permeability for SGG is significantly high compared to normal selenium (7.2 nM of selenium for 25 nM SGG compared with 5.2 nM selenium for 25 nM sodium selenite). There was no apoptosis with SGG and also it protects DNA from hydroxyl radical induced breakage. Likewise no adverse effect on mitochondria and cytoskeleton was observed for 25 nM of SGG. Overall results reveal that SGG is highly suitable for biomedical research application. PMID:24098647

  15. 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).

  16. Water-Soluble Spinel Ferrites by a Modified Polyol Process as Contrast Agents in MRI

    SciTech Connect

    Basina, Georgia [Institute of Materials Science, N.C.S.R. 'Demokritos' Agia Paraskevi 15310 Athens (Greece); Department of Physics and Astronomy, University of Delaware, DE 19716, Newark (United States); Tzitzios, Vasilis; Niarchos, Dimitris [Institute of Materials Science, N.C.S.R. 'Demokritos' Agia Paraskevi 15310 Athens (Greece); Li Wanfeng; Khurshid, Hafsa; Hadjipanayis, George [Department of Physics and Astronomy, University of Delaware, DE 19716, Newark (United States); Mao Hui [Department of Radiology, Emory University, School of Medicine, GA 30322, Atlanta (United States); Hadjipanayis, Costas [Department of Neurological Surgery, Emory University, School of Medicine, GA 30322, Atlanta (United States)

    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. 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 ?-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

  18. Ultrasonic cavitation induced water in vegetable oil emulsion droplets--a simple and easy technique to synthesize manganese zinc ferrite nanocrystals with improved magnetization.

    PubMed

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

    2012-05-01

    In the present investigation, synthesis of manganese zinc ferrite (Mn(0.5)Zn(0.5)Fe(2)O(4)) nanoparticles with narrow size distribution have been prepared using ultrasound assisted emulsion (consisting of rapeseed oil as an oil phase and aqueous solution of Mn(2+), Zn(2+) and Fe(2+) acetates) and evaporation processes. The as-prepared ferrite was nanocrystalline. In order to remove the small amount of oil present on the surface of the ferrite, it was subjected to heat treatment at 300 °C for 3h. Both the as-prepared and heat treated ferrites have been characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), TGA/DTA, transmission electron microscopy (TEM) and energy dispersion X-ray spectroscopy (EDS) techniques. As-prepared ferrite is of 20 nm, whereas the heat treated ferrite shows the size of 33 nm. In addition, magnetic properties of the as-prepared as well as the heat treated ferrites have also been carried out and the results of which show that the spontaneous magnetization (?(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. PMID:22113061

  19. Preparation of novel (-)-gossypol nanoparticles and the effect on growth inhibition in human prostate cancer PC-3 cells in vitro

    PubMed Central

    JIN, CAI-LING; CHEN, MEI-LING; WANG, YING; KANG, XIAO-CHUN; HAN, GUANG-YE; XU, SU-LING

    2015-01-01

    The aim of the present study was to investigate the antitumor effects and possible mechanism of (-)-gossypol nanoparticles, loaded with vv polyethylene glycol-maleimide (mPEG-Mal), in vitro. Emulsification-volatilization was used to prepare the loaded (-)-gossypol nanoparticles. The toxicity of blank nanoparticles on human prostate cancer PC-3 cells and human prostate RWPE-1 cells was measured. The antitumor effects of the nanoparticles on PC-3 cells were evaluated by an MTT assay, acridine orange staining and transmission electron microscopy in vitro, and the results were compared with those of free (-)-gossypol. In addition, the mRNA expression levels of Bcl-2 and Bak were measured using semi-quantitative reverse transcription polymerase chain reaction. The growth inhibition activity of the loaded (-)-gossypol nanoparticles was found to be dose- and time-dependent, and similar to the activity of free (-)-gossypol. The nanoparticles induced apoptotic morphological changes on the PC-3 cells, downregulating the mRNA expression level of Bcl-2 and upregulating the mRNA expression level of Bak. Blank nanoparticles exhibited no evident toxicity on PC-3 and RWPE-1 cells at a high dose. Therefore, the mPEG-Mal loaded (-)-gossypol nanoparticles demonstrated a favorable antitumor activity and no toxicity. The nanoparticles were able to induce the apoptosis of prostate cancer cells; thus, may be a potential antitumor nanodrug. PMID:25667612

  20. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS

    SciTech Connect

    Seetala V. Naidu; Upali Siriwardane

    2005-01-14

    We have developed effective nanoparticle incorporated heterogeneous F-T catalysts starting with the synthesis of Fe, Co, Cu nanoparticles using Fe(acac){sub 3}, Co(acac){sub 2}, and Cu(acac){sub 2} precursors and incorporating the nanoparticles into alumina sol-gel to yield higher alkanes production. SEM/EDX, XRD, BET, VSM and SQUID experimental techniques were used to characterize the catalysts, and GC/MS were used for catalytic product analysis. The nanoparticle oxide method gave the highest metal loading. In case of mixed metals it seems that Co or Cu interferes and reduces Fe metal loading. The XRD pattern for nanoparticle mixed metal oxides show alloy formation between cobalt and iron, and between copper and iron in sol-gel prepared alumina granules. The alloy formation is also supported by DTA and VMS data. The magnetization studies were used to estimate the catalyst activity in pre- and post-catalysts. A lower limit of {approx}40% for the reduction efficiency was obtained due to hydrogenation at 450 C for 4 hrs. About 85% of the catalyst has become inactive after 25 hrs of catalytic reaction, probably by forming carbides of Fe and Co. The low temperature (300 K to 4.2 K) SQUID magnetometer results indicate a superparamagnetic character of metal nanoparticles with a wide size distribution of < 20 nm nanoparticles. We have developed an efficient and economical procedure for analyzing the F-T products using low cost GC-TCD system with hydrogen as a carrier gas. Two GC columns DC 200/500 and Supelco Carboxen-1000 column were tested for the separation of higher alkanes and the non-condensable gases. The Co/Fe on alumina sol-gel catalyst showed the highest yield for methane among Fe, Co, Cu, Co/Fe, Cu/Co, Fe/Cu. The optimization of CO/H{sub 2} ratio indicated that 1:1 ratio gave more alkanes distribution in F-T process with Co/Fe (6% each) impregnated on alumina mesoporous catalyst.

  1. In vitro MRI of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles prepared via modified double emulsion evaporation mechanism.

    PubMed

    Ahmed, Naveed; Ahmad, Nasir M; Fessi, Hatem; Elaissari, Abdelhamid

    2015-06-01

    Hybrid magnetic particles are being applied in biomedical field for various aims. One of such aim is use of magnetic particles for diagnostic purposes especially in imaging mechanisms. In vitro magnetic resonance imaging of biodegradable hybrid (iron oxide/polycaprolactone) magnetic nanoparticles is carried out. Hybrid magnetic nanoparticles were prepared by encapsulation of iron oxide nanoparticles (IONPs) in polycaprolactone (PCL) via modified double emulsion evaporation technique. Both the IONPs and hybrid nanoparticles were characterized for their sizes, zeta potential, microscopic, thermogravimetric, and magnetism. Prepared particles were investigated for T1 and T2 weighted enhancement of contrast in vitro in water. A comparison of the prepared particles was done with commercially available Gadolinium for the contrast efficiency in MRI. Results showed the prepared particles exhibited nanosize range, good morphology and superparamagnetic character. The enhancement in the MRI contrast of the prepared particles was observed and found to depend on type of the prepared particles. Comparison of the MRI contrast of the prepared particles with the commercial Gadolinium suggests their usefulness as T2 contrast agent. PMID:25960142

  2. Preparation of Mn{sub 2}SnO{sub 4} nanoparticles as the anode material for lithium secondary battery

    SciTech Connect

    Lei Shuijin [School of Materials Science and Engineering, Nanchang University, No. 999, Xuefu Avenue Honggutan New District, Nanchang, Jiangxi 330031 (China)], E-mail: shjlei@ncu.edu.cn; Tang Kaibin [Nanomaterial and Nanochemistry, Hefei National Laboratory for Physical Sciences at Micro-scale, University of Science and Technology of China, Hefei, Anhui 230026 (China)], E-mail: kbtang@ustc.edu.cn; Chen Chunhua; Jin Yi [Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhou Lang [School of Materials Science and Engineering, Nanchang University, No. 999, Xuefu Avenue Honggutan New District, Nanchang, Jiangxi 330031 (China)

    2009-02-04

    The ultrafine Mn{sub 2}SnO{sub 4} nanoparticles with diameters of 5-10 nm have been prepared by thermal decomposition of precursor MnSn(OH){sub 6}. The MnSn(OH){sub 6} nanoparticles precursor was synthesized by a hydrothermal microemulsion method. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and electron diffraction have been employed to characterize the crystal structures and morphologies of the as-prepared samples. High-resolution transmission electron microscopy observations revealed that the as-synthesized nanoparticles were single crystals. The thermal characterization was studied by differential thermal analysis and thermogravimetry analysis measurements. Electrochemical test showed that the Mn{sub 2}SnO{sub 4} nanoparticles exhibited a high initial charge-discharge capacity of 1320 mAh/g.

  3. Preparation of estradiol chitosan nanoparticles for improving nasal absorption and brain targeting

    Microsoft Academic Search

    Xiaomei Wang; Na Chi; Xing Tang

    2008-01-01

    The estradiol(E2)-loaded chitosan nanoparticles (CS-NPs) were prepared by ionic gelation of chitosan with tripolyphosphate anions (TPP). The CS-NPs had a mean size of (269.3±31.6)nm, a zeta potential of +25.4mV, and loading capacity of E2 CS-NPs suspension was 1.9mgml?1, entrapment efficiency was 64.7% on average. Subsequently, this paper investigated the levels of E2 in blood and the cerebrospinal fluid (CSF) in

  4. Synthesis and characterization of porous Al(III) metal-organic framework nanoparticles as a new precursor for preparation of Al 2O 3 Nanoparticles

    Microsoft Academic Search

    Mohammad Sadegh Yazdan Parast; Ali Morsali

    2011-01-01

    A porous aluminum(III) metal-organic framework, [Al8(OH)15(H2O)3(btc)3]n, MIL-110, has been synthesized by hydrothermal method and characterized by elemental analyses, X-ray powder diffraction (XRD) and IR spectroscopy. MIL-110 (Al) was calcinated at different temperatures under air atmosphere to prepare Al2O3 and in another process MIL-110 (Al) nanoparticles were prepared by using oleic acid. The product of each step was characterized by scanning

  5. Preparation of nano-gypsum from anhydrite nanoparticles: Strongly increased Vickers hardness and formation of calcium sulfate nano-needles

    Microsoft Academic Search

    Neil Osterwalder; Stefan Loher; Robert N. Grass; Tobias J. Brunner; Ludwig K. Limbach; Samuel C. Halim; Wendelin J. Stark

    2007-01-01

    The preparation of calcium sulfate by flame synthesis resulted in the continuous production of anhydrite nanoparticles of\\u000a 20–50 nm size. After compaction and hardening by the addition of water, the anhydrite nanoparticles reacted to nano-gypsum\\u000a which was confirmed by X-ray diffraction, diffuse reflectance IR spectroscopy and thermal analysis. Mechanical properties\\u000a were investigated in terms of Vickers hardness and revealed an up

  6. Magnetic Fe 3O 4\\/poly(styrene-co-acrylamide) composite nanoparticles prepared by microwave-assisted emulsion polymerization

    Microsoft Academic Search

    Jingjing Huang; Hui Pen; Zushun Xu; Changfeng Yi

    2008-01-01

    Monodisperse magnetic Fe3O4\\/poly(styrene-co-acrylamide) [Fe3O4\\/poly(St–AAm)] nanoparticles with diameters of 50–300nm were prepared by emulsion polymerization with microwave irradiation in the presence of a ferrofluid coated with oleic acid (OA) and sodium dodecyl sulfate (SDS). The influence of some polymerization parameters were examined in detail, such as monomer content and the ferrofluid content. The structure of the obtained magnetic nanoparticles was characterized

  7. Preparation and Characterization of beta-Carotene Encapsulated Chitosan, Oleic Acid Coated Fe3O4 Nanoparticles

    Microsoft Academic Search

    P. Divya; B. Anbarasan; S. Ramaprabhu

    2011-01-01

    In this work ?-Carotene encapsulated Chitosan, oleic acid coated Fe3O4 nanoparticles were prepared by modifying solvent displacement technique. Nanoparticles containing ?-carotene were produced by interfacial deposition of the metal oxide\\/polymer nanocomposite, due to the displacement of acetone from the dispersed phase. Tween 20 is used as the stabilizing agent. ?-carotene was entrapped in the metal oxide\\/polymeric matrix. Particles were characterized

  8. Preparation of Ultrafine Poly(ethylene oxide)\\/Poly(ethylene glycol) Fibers Containing Silver Nanoparticles as Antibacterial Coating

    Microsoft Academic Search

    P. Rujitanaroj; N. Pimpha; P. Supaphol

    2007-01-01

    Poly(ethylene oxide) (PEO) solutions containing various amounts of poly(ethylene glycol) (PEG) and various amount of silver (Ag) nanoparticles were prepared. The occurrence of Ag nanoparticles was by a direct reduction of Ag+ ions from the addition of silver nitrate (AgNO3) of varying amount (0.5-2.5%) in the PEO 5%\\/PEG (2 and 35 kDa) 1-15% solutions. The average diameter of the Ag

  9. Effect of Loading and Surface Modification of Nanoparticles on the Properties of PMMA\\/Silica Nanocomposites Prepared via in Situ Free Radical Polymerization

    Microsoft Academic Search

    Mehdi Salami-Kalajahi; Vahid Haddadi-Asl; Saeid Rahimi-Razin; Farid Behboodi-Sadabad; Hossein Roghani-Mamaqani; Mohammad Najafi

    2012-01-01

    A number of batch polymerizations were performed to study the effect of pristine nanoparticle loading on the properties of PMMA\\/silica nanocomposites. In order to improve the dispersion of silica nanoparticles in PMMA matrix, the silanol groups of the silica are functionalized with methacrylate groups and modified nanoparticles were used to synthesize PMMA\\/modified silica nanocomposites. Prepared samples were characterized by thermogravimetric

  10. Morphological and magnetic characterization of Fe, Co, and FeCo nanoplates and nanoparticles prepared by surfactants-assisted ball milling

    E-print Network

    Liu, J. Ping

    Morphological and magnetic characterization of Fe, Co, and FeCo nanoplates and nanoparticles report here the preparation of Fe, Co, and FeCo nanoplates and nanoparticles by ball milling, the Fe, Co, and FeCo nanoplates and nanoparticles with different sizes were successfully obtained, from

  11. Characterization and photocatalytic activity of Ag-Cu/TiO2 nanoparticles prepared by sol-gel method.

    PubMed

    Behnajady, Mohammad A; Eskandarloo, Hamed

    2013-01-01

    In this study, monometallic and bimetallic silver and copper doped TiO2 nanoparticles were prepared by sol-gel method. Structural and morphological characterizations of prepared nanoparticles were performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and N2 physisorption techniques. Co-doped TiO2 nanoparticles displayed pure anatase phase with 20-30 nm particle size and a humdrum distribution. The stability of anatase phase was increased with co-doping of silver and copper to TiO2 lattice. In addition, the co-doped TiO2 nanoparticles had a mesoporous structure with slit-shaped pores. The photocatalytic activity of all samples was evaluated in the photocatalytic removal of C.I. Acid Orange 7. Co-doped TiO2 nanoparticles by Ag and Cu were shown to have highest activity as compared with the Ag/TiO2, Cu/TiO2 and pure TiO2 nanoparticles. The best performance of co-doped TiO2 nanoparticles was observed for a sample calcined under 550 degrees C, containing optimum molar contents of silver (0.08 mol%) and copper (0.01 mol%) dopant ions. PMID:23646771

  12. La-doped ZnO nanoparticles: Simple solution-combusting preparation and applications in the wastewater treatment

    SciTech Connect

    Wu, Tingting [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Ni, Yonghong, E-mail: niyh@mail.ahnu.edu.cn [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Ma, Xiang, E-mail: max@nju.edu.cn [Centers of Modern Analysis, Nanjing University, Nanjing 210093 (China); Hong, Jianming [Centers of Modern Analysis, Nanjing University, Nanjing 210093 (China)

    2013-11-15

    Graphical abstract: La-doped ZnO nanoparticles have been successfully prepared by a simple solution combustion route and exhibit good adsorption for Cu and Pb ion from water systems. - Highlights: • La-doped ZnO nanoparticles were successfully prepared via a simple solution-combustion route. • The integration of La{sup 3+} ions into ZnO decreased the band-gap of ZnO nanoparticles. • La-doped ZnO nanoparticles could remove more Pb and Cu ions from water resources than undoped ZnO. - Abstract: La-doped ZnO nanoparticles have been successfully synthesized by a simple solution combustion method via employing a mixture of ethanol and ethyleneglycol (v/v = 60/40) as the solvent. Zinc acetate and oxygen gas in the atmosphere were used as zinc and oxygen sources, and La(NO{sub 3}){sub 3} as the doping reagent. The as-obtained product was characterized by means of powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Experiments showed that La-doped ZnO nanoparticles exhibited the higher capacities for the removal of Pb{sup 2+} and Cu{sup 2+} ions in water resource than undoped ZnO nanoparticles.

  13. Scalable preparation of ultrathin silica-coated Ag nanoparticles for SERS application.

    PubMed

    Hu, Yanjie; Shi, Yunli; Jiang, Hao; Huang, Guangjian; Li, Chunzhong

    2013-11-13

    Silica-coated Ag nanoparticles (Ag@SiO2 NPs) have been successfully prepared by a scalable flame spray pyrolysis (FSP) technique with production rate up to 4 g/h in laboratory-scale. The ultrathin SiO2 shell, with a thickness 1 nm, not only effectively avoids the intersintering of Ag nanoparticles core at the high temperature, but also serves as a protective layer of the SERS-active nanostructure. The silica-coated Ag nanoparticles form agglomerates in the large temperature gradient zone, which with several nanometers gaps from each other but not contact. Such an intriguing feature can result in more Raman hot-spots generated at the gaps among Ag core active sites, which will beneficial for the whole SERS substrate enhancement. The results demonstrate that a maximum enhancement factor can reach ~10(5) with a detectable concentration as low as 10(-10) M for rhodamine 6G (R6G) molecules, indicating that the as-obtained unique nanostructure will be a promising candidate for SERS applications. PMID:24117322

  14. Novel superparamagnetic iron oxide nanoparticles for tumor embolization application: preparation, characterization and double targeting.

    PubMed

    Chen, Xiaoli; Lv, Haiyan; Ye, Min; Wang, Shengyu; Ni, Erru; Zeng, Fanwei; Cao, Chang; Luo, Fanghong; Yan, Jianghua

    2012-04-15

    The goal of this study was to develop novel embolic nanoparticles for targeted tumor therapy with dual targeting: magnetic field-guided and peptide-directed targeting. The embolic nanoparticles SP5.2/tTF-OCMCs-SPIO-NPs were prepared by surface-modifying of superparamagnetic iron oxide nanoparticles (SPIO-NPs) with o-carboxymethylchitosans (OCMCs) and SP5.2/tTF (SP5.2: a peptide binding to VEGFR-1; tTF: truncated tissue factor) to improve their stability and to target over-expressing VEGFR-1 cells. The physicochemical characterization results showed that the OCMCs-SPIO-NPs have a spherical or ellipsoidal morphology with an average diameter of 10-20 nm. And they possess magnetism with a saturation magnetization of 66.1 emu/g, negligible coercivity and remanence at room temperature. In addition, the confocal microscopy, Prussian blue staining and FX activation analysis respectively demonstrated the peptide-directed targeting, magnetic field-guided targeted and blood coagulation activity of the SP5.2/tTF-OCMCs-SPIO-NPs. These properties separately belong to SP5.2, Fe(3)O(4) and tTF moieties of the SP5.2/tTF-OCMCs-SPIO-NPs. Thus these SP5.2/tTF-OCMCs-SPIO-NPs with double-targeting function should have a potential application in embolization therapy of tumor blood vessels. PMID:22310463

  15. Preparation and Characterization Challenges to Understanding Environmental and Biological Impacts of Nanoparticles

    PubMed Central

    Karakoti, A.S.; Munusamy, P.; Hostetler, K; Kodali, V.; Kuchibhatla, S.; Orr, G.; Pounds, J.G.; Teeguarden, J.G.; Thrall, B.D.; Baer, D.R.

    2012-01-01

    Increasingly, it is recognized that understanding and predicting nanoparticle behavior is often limited by the degree to which the particles can be reliably produced and adequately characterized. Two examples that demonstrate how sample preparation methods and processing history may significantly impact particle behavior are: 1) an examination of cerium oxide (ceria) particles reported in the literature in relation to the biological responses observed and 2) observations related that influence synthesis and aging of ceria nanoparticles. Examining data from the literature for ceria nanoparticles suggests that thermal history is one factor that has a strong influence on biological impact. Thermal processing may alter many physicochemical properties of the particles, including density, crystal structure, and the presence of surface contamination. However, these properties may not be sufficiently recorded or reported to determine the ultimate source of an observed impact. A second example shows the types of difficulties that can be encountered in efforts to apply a well-studied synthesis route to producing well-defined particles for biological studies. These examples and others further highlight the importance of characterizing particles thoroughly and recording details of particle processing and history that too often are underreported. PMID:23430137

  16. Preparation and physicochemical characterization of aqueous dispersions of coenzyme Q10 nanoparticles.

    PubMed

    Siekmann, B; Westesen, K

    1995-02-01

    The present study describes a novel pharmaceutical formulation of coenzyme Q10, viz. submicron-sized dispersions of the substance prepared by emulsification of molten coenzyme Q10 in an aqueous phase. Photon correlation spectroscopy reveals mean diameters of 60 to 300 nm depending on process parameters. Coenzyme Q10 nanoparticles remain stable on storage for more than 30 months. Lipophilic drugs can be incorporated into the nanoparticles demonstrating their potential use as a drug carrier system. Transmission electron micrographs of freeze-fractured replica show spherical particles with an amorphous core. Cryo-electron microscopy reveals the coexistence of small unilamellar vesicles in phospholipid stabilized dispersions. Thermoanalysis and X-ray studies indicate that the dispersed and emulsified coenzyme Q10 does not recrystallize even at 4 degrees C over 30 months. These agree with 1H NMR data which demonstrate that coenzyme Q10 molecules have a high mobility when formulated as nanoparticles and that colloidally dispersed coenzyme Q10 remains in the state of a supercooled melt. Despite the high melting point of the bulk material, coenzyme Q10 dispersions represent no suspensions but O/W emulsions according to the IUPAC definition (1). PMID:7784334

  17. Preparation of crystalline starch nanoparticles using cold acid hydrolysis and ultrasonication.

    PubMed

    Kim, Hee-Young; Park, Dong June; Kim, Jong-Yea; Lim, Seung-Taik

    2013-10-15

    Waxy maize starch in an aqueous sulfuric acid solution (3.16 M, 14.7% solids) was hydrolyzed for 2-6 days, either isothermally at 40 °C or 4 °C, or at cycled temperatures of 4 and 40 °C (1 day each). The starch hydrolyzates were recovered as precipitates after centrifuging the dispersion (10,000 rpm, 10 min). The yield of starch hydrolyzates depended on the hydrolysis temperature and time, which varied from 6.8% to 78%. The starch hydrolyzed at 40 °C or 4/40 °C exhibited increased crystallinity determined by X-ray diffraction analysis, but melted in broader temperature range (from 60 °C to 110 °C). However, the starch hydrolyzed at 4 °C displayed the crystallinity and melting endotherm similar to those of native starch. The starch hydrolyzates recovered by centrifugation were re-dispersed in water (15% solids), and the dispersion was treated by an ultrasonic treatment (60% amplitude, 3min). The ultrasonication effectively fragmented the starch hydrolyzates to nanoparticles. The hydrolyzates obtained after 6 days of hydrolysis were more resistant to the ultrasonication than those after 2 or 4 days, regardless of hydrolysis temperatures. The starch nanoparticles could be prepared with high yield (78%) and crystallinity by 4 °C hydrolysis for 6 days followed by ultrasonication. Scanning electron microscopy revealed that the starch nanoparticles had globular shapes with diameters ranging from 50 to 90 nm. PMID:23987348

  18. Preparation and in vivo evaluation of solid lipid nanoparticles of griseofulvin for dermal use.

    PubMed

    Aggarwal, Nidhi; Goindi, Shishu

    2013-04-01

    Griseofulvin-loaded solid lipid nanoparticles (SLNs) were prepared by hot microemulsion technique and optimized for type and concentration of lipid and surfactant. The optimized SLN composition was characterized in terms of particle shape and size, drug entrapment efficiency, pH, stability, spreadability, ex-vivo skin permeation, dermatokinetics, skin sensitivity, in vitro antifungal assay and in vivo antifungal activity against Microsporum canis using guinea pig model for dermatophytosis. The cumulative amount of drug permeated through excised mice skin from SLNs was more than 5-folds as compared to permeation from conventional cream base. Fluorescent microscopy revealed presence of nanoparticles in the skin layers suggesting the penetration of nanoparticles into the skin owing to their nano-size and thence a controlled drug release. A complete mycological and clinical cure was observed in M. canis infected guinea pigs after twice daily application of SLN gel containing griseofulvin for 8 days. Also, the formulation was observed to be non-sensitizing, histopathologically safe, and SLN gel was stable at 5 +/- 3 degrees C, 25 +/- 2 degrees C and 40 +/- 2 degrees C for a period of six months. It can be concluded from our study that SLNs provide a good skin permeation effect and may be a promising carrier for topical delivery of griseofulvin. PMID:23621015

  19. Synthesis, structure, and scintillation of Ce-doped gadolinium oxyorthosilicate nanoparticles prepared by solution combustion synthesis

    NASA Astrophysics Data System (ADS)

    Jacobsohn, L. G.; Tornga, S. C.; Blair, M. W.; Bennett, B. L.; Muenchausen, R. E.; Wang, R.; Crozier, P. A.; Cooke, D. W.

    2011-10-01

    The synthesis of Ce-doped Gd oxyorthosilicate nanoparticles using the solution combustion synthesis (SCS) method was investigated as a function of the amount of SiO2 in the precursor mixture. The SCS product consists of mixtures of Ce-doped Gd2SiO5, Gd4.67(SiO4)3O, and Gd2O3, whose relative concentrations depend on the amount of SiO2 in the precursor mixture; the synthesis of GSO:Ce was obtained with a reduction by 30% of the SiO2 content. Accordingly, this is the brightest material produced, with a photoluminescence signal that is comparable to that obtained from the bulk sample. Thermoluminescence (TL) results showed a considerably lower concentration of trapping defects in the nanoparticles than in the bulk sample. A previous study [E. G. Yukihara, L. G. Jacobsohn, M. W. Blair, B. L. Bennett, S. C. Tornga, and R. E. Muenchausen, J. Lumin. 130, 2309-2316 (2010)] reporting a comparison between photoluminescence and scintillation measurements, coupled to the TL characterization, suggests that surfaces play a major role in decreasing the scintillation efficiency of the nanoparticles. These results show that it is possible to prepare relatively bright scintillator powders using the SCS method.

  20. Synthesis and preparation of fluorinated polycarbonates enhancing the light absorption of fluorescent nanoparticles.

    PubMed

    Park, Teahoon; Ali, Syed Nawazish; You, Jungmok; Kim, Byeonggwan; Kim, Eunkyoung

    2013-09-01

    A new synthetic method for fluorinated polycarbonates without the use of any toxic phosgene gas is presented. The synthesis consists of a monomer synthesis followed by polymerization. The fluorinated polycarbonate (FPC) was confirmed by Fourier transform infrared spectroscopy (FT-IR) and NMR spectroscopy. The refractive index of the polymer was 1.466 determined by an Abbe refractometer. The contact angle measurement of the FPC films showed the hydrophobicity with water contact angle about 112.6 degrees. These films of varying thicknesses had over 98% transmittance. Taking advantage of the hydrophobicity and high transmittance of the FPCs, nanoparticles of FPCs were prepared directly in an aqueous solution with a reprecipitation method. Combining FPC solution with a solution containing fluorescent polymer (DTMSPV), nanoparticles with a core-shell structure were obtained easily with the reprecipitation method. The fluorescence intensity of the DTMSPV in the core-shell nanoparticles were much enhanced up to 34.1% compared to the molecularly dispersed DTMSPV solution. PMID:24205614

  1. Zinc ferrite nanoparticles activate IL-1b, NFKB1, CCL21 and NOS2 signaling to induce mitochondrial dependent intrinsic apoptotic pathway in WISH cells.

    PubMed

    Saquib, Quaiser; Al-Khedhairy, Abdulaziz A; Ahmad, Javed; Siddiqui, Maqsood A; Dwivedi, Sourabh; Khan, Shams T; Musarrat, Javed

    2013-12-01

    The present study has demonstrated the translocation of zinc ferrite nanoparticles (ZnFe2O4-NPs) into the cytoplasm of human amnion epithelial (WISH) cells, and the ensuing cytotoxicity and genetic damage. The results suggested that in situ NPs induced oxidative stress, alterations in cellular membrane and DNA strand breaks. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and neutral red uptake (NRU) cytotoxicity assays indicated 64.48 ± 1.6% and 50.73 ± 2.1% reduction in cell viability with 100 ?g/ml of ZnFe2O4-NPs exposure. The treated WISH cells exhibited 1.2-fold higher ROS level with 0.9-fold decline in membrane potential (??m) and 7.4-fold higher DNA damage after 48h of ZnFe2O4-NPs treatment. Real-time PCR (qPCR) analysis of p53, CASP 3 (caspase-3), and bax genes revealed 5.3, 1.6, and 14.9-fold upregulation, and 0.18-fold down regulation of bcl 2 gene vis-à-vis untreated control. RT(2) Profiler™ PCR array data elucidated differential up-regulation of mRNA transcripts of IL-1b, NFKB1, NOS2 and CCL21 genes in the range of 1.5 to 3.7-folds. The flow cytometry based cell cycle analysis suggested the transfer of 15.2 ± 2.1% (p<0.01) population of ZnFe2O4-NPs (100 ?g/ml) treated cells into apoptotic phase through intrinsic pathway. Over all, the data revealed the potential of ZnFe2O4-NPs to induce cellular and genetic toxicity in cells of placental origin. Thus, the significant ROS production, reduction in ??m, DNA damage, and activation of genes linked to inflammation, oxidative stress, proliferation, DNA damage and repair could serve as the predictive toxicity and stress markers for ecotoxicological assessment of ZnFe2O4-NPs induced cellular and genetic damage. PMID:24035972

  2. Magnetic field directed assembly of superstructures of ferrite-ferroelectric core-shell nanoparticles and studies on magneto-electric interactions

    NASA Astrophysics Data System (ADS)

    Srinivasan, G.; Sreenivasulu, G.; Benoit, Crystal; Petrov, V. M.; Chavez, F.

    2015-05-01

    Composites of ferromagnetic and ferroelectric are of interest for studies on mechanical strain mediated magneto-electric (ME) interactions and for useful technologies. Here, we report on magnetic-field-assisted-assembly of barium titanate (BTO)-nickel ferrite (NFO) core-shell particles into linear chains and 2D/3D arrays and measurements of ME effects in such assemblies. First, we synthesized the core-shell nano-particles with 50-600 nm BTO and 10-200 nm NFO by chemical self-assembly by coating the ferroic particles with complementary coupling groups and allowing them to self-assemble in the presence of a catalyst via the "click" reaction. The core-shell structure was confirmed with electron microscopy and scanning probe microscopy. We obtained superstructure of the core-shell particles by subjecting them to a magnetic field gradient that exerts an attractive force on the particles and align them toward the regions of high field strengths. At low particle concentration, linear chains were formed and they evolved into 2D and 3D arrays at high particle concentrations. Magnetoelectric characterization on unassembled films and assembled arrays has been performed through measurements of low-frequency ME voltage coefficient (MEVC) by subjecting the sample to a bias magnetic field and an ac magnetic field. The MEVC is higher for field-assembled samples than for unassembled films and is found to be sensitive to field orientation with a higher MEVC for magnetic fields parallel to the array direction than for magnetic fields perpendicular to the array. A maximum MEVC of 20 mV/cm Oe, one of the highest reported for any bulk nanocomposite, is measured across the array thickness. A model is provided for ME coupling in the superstructures of BTO-NFO particulate composites. First, we estimated the MEVC for a free-standing BTO-NFO core-shell particle and then extended the model to include an array of linear chains of the particles. The theoretical estimates are in qualitative agreement with the data.

  3. Nonaqueous synthesis of metal oxide nanoparticles: Short review and doped titanium dioxide as case study for the preparation of transition metal-doped oxide nanoparticles

    SciTech Connect

    Djerdj, Igor [ETH Zuerich, Department of Materials, Wolfgang-Pauli-Strasse 10, 8093 Zuerich (Switzerland)], E-mail: igor.djerdj@mat.ethz.ch; Arcon, Denis [Institute Jozef Stefan, Jamova 39, 1000 Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Jaglicic, Zvonko [Institute of Mathematics, Physics and Mechanics, Jadranska 19, 1000 Ljubljana (Slovenia); Faculty of Civil and Geodetic Engineering, University of Ljubljana, Jamova 2, 1000 Ljubljana (Slovenia); Niederberger, Markus [ETH Zuerich, Department of Materials, Wolfgang-Pauli-Strasse 10, 8093 Zuerich (Switzerland)], E-mail: markus.niederberger@mat.ethz.ch

    2008-07-15

    The liquid-phase synthesis of metal oxide nanoparticles in organic solvents under exclusion of water is nowadays a well-established alternative to aqueous sol-gel chemistry. In this article, we highlight some of the advantages of these routes based on selected examples. The first part reviews some recent developments in the synthesis of ternary metal oxide nanoparticles by surfactant-free nonaqueous sol-gel routes, followed by the discussion of the morphology-controlled synthesis of lanthanum hydroxide nanoparticles, and the presentation of structural peculiarities of manganese oxide nanoparticles with an ordered Mn vacancy superstructure. These examples show that nonaqueous systems, on the one hand, allow the preparation of compositionally complex oxides, and, on the other hand, make use of the organic components (initially present or formed in situ) in the reaction mixture to tailor the morphology. Furthermore, obviously even the crystal structure can differ from the corresponding bulk material like in the case of MnO nanoparticles. In the second part of the paper we present original results regarding the synthesis of dilute magnetic semiconductor TiO{sub 2} nanoparticles doped with cobalt and iron. The structural characterization as well as the magnetic properties with special attention to the doping efficiency is discussed. - Graphical abstract: In the first part of this article, nonaqueous sol-gel routes to ternary metal oxide nanoparticles are briefly reviewed, followed by the discussion of the morphology-controlled synthesis of lanthanum hydroxide nanoparticles, and the appearance of an unprecedented superstructure in MnO nanoparticles. In the second part, doping experiments of TiO{sub 2} with Fe and Co are presented, along with their characterization including magnetic measurements.

  4. Preparation and characterization of zinc sulfide nanoparticles under high-gravity environment

    SciTech Connect

    Chen Jianfeng; Li Yaling; Wang Yuhong; Yun, Jimmy; Cao Dapeng

    2004-02-02

    Nanosized ZnS particles were prepared under high-gravity environment generated by the rotating packed bed reactor (RPBR) using zinc nitrate solution and hydrogen sulfide gas as raw materials. The effects of experimental conditions such as reactant concentration, reaction temperature, rotating speed of the RPBR and aging time, on the preparation of nanosized ZnS particles were investigated. A set of suitable operating parameters (the aging time of 48 h, concentration of zinc nitrate of 0.1 mol/l, reaction temperature of 45 deg. C and rotating speed of the RPBR of 1500-1800 rotation/min) for the preparation of nanosized ZnS were recommended. Under these optimum conditions, well-dispersed ZnS nanoparticles was obtained. The crystal structure, optical properties, size and morphology of the product were also characterized by XRD, UV-Vis spectrophotometer, and TEM, respectively. Results indicate that the prepared ZnS has a good absorption for light in the wavelength range of 200-330 nm. XRD analysis also shows the prepared ZnS is in a sphalerite crystal phase. The process has great potential of commercialization.

  5. Paclitaxel loaded niosome nanoparticle formulation prepared via reverse phase evaporation method: an in vitro evaluation.

    PubMed

    Zarei, M; Norouzian, D; Honarvar, B; Mohammadi, M; Shamabadi, H Ebrahimi; Akbarzadeh, A

    2013-03-15

    Niosoms are nanoparticles used in drug delivery systems. Niosomes are prepared by various methods. In this research niosoms were prepared by reverse phase evaporation and the factors affecting the niosomes formation were studied. Percent of paclitaxel pegylated and non-pegylated prepared with Span 60 were 95 and 92, respectively while for those of pegylated and non-pegylated niosomes with Span 20, 94 and 90, respectively. In addition, the average diameters of pegylated and no-pegylated prepared with Span 60 and 20 were determined to be 191, 214, 244 and 284 nm, respectively. The amount of released drug (48 h) from pegylated and non pegylated formulations in the presence of Spans 60 and 20 were 8, 10, 6, 7%, respectively. Cytotoxicities ofpaclitaxel niosom polyethyleneglycol, paclitaxel niosome and free paclitaxel on MCF-7 cell line after 48 hours were studied by MTT assay. The results showed the formulation prepared with Span 60 is more effective than that of Span 20 and the IC50 of the former was decreased twice while IC50 of the later decreased 1.5 times. PMID:24498794

  6. Comparative studies of salinomycin-loaded nanoparticles prepared by nanoprecipitation and single emulsion method

    NASA Astrophysics Data System (ADS)

    Wang, Qin; Wu, Puyuan; Ren, Wei; Xin, Kai; Yang, Yang; Xie, Chen; Yang, Chenchen; Liu, Qin; Yu, Lixia; Jiang, Xiqun; Liu, Baorui; Li, Rutain; Wang, Lifeng

    2014-07-01

    To establish a satisfactory delivery system for the delivery of salinomycin (Sal), a novel, selective cancer stem cell inhibitor with prominent toxicity, gelatinase-responsive core-shell nanoparticles (NPs), were prepared by nanoprecipitation method (NR-NPs) and single emulsion method (SE-NPs). The gelatinase-responsive copolymer was prepared by carboxylation and double amination method. We studied the stability of NPs prepared by nanoprecipitation method with different proportions of F68 in aqueous phase to determine the best proportion used in our study. Then, the NPs were prepared by nanoprecipitation method with the best proportion of F68 and single emulsion method, and their physiochemical traits including morphology, particle size, zeta potential, drug loading content, stability, and in vitro release profiles were studied. The SE-NPs showed significant differences in particle size, drug loading content, stability, and in vitro release profiles compared to NR-NPs. The SE-NPs presented higher drug entrapment efficiency and superior stability than the NR-NPs. The drug release rate of SE-NPs was more sustainable than that of the NR-NPs, and in vivo experiment indicated that NPs could prominently reduce the toxicity of Sal. Our study demonstrates that the SE-NPs could be a satisfactory method for the preparation of gelatinase-responsive NPs for intelligent delivery of Sal.

  7. An overview of magnetism of spinel nanoferrite particles and A study of chromium substituted Zn-Mn ferrites nanostructures via sol-gel method

    Microsoft Academic Search

    C Ramesh; Maniysundar

    2011-01-01

    In this review article, we attempt to describe the structure of various spinel ferrites like zinc ferrite, nickel-zinc ferrite, manganese-zinc ferrite and cobalt ferrite. It also describes the important magnetic properties of these spinel ferrites. The article also focused Nanocrystalline ZnMn1?xCrxFeO4 (1.0 >x > 0) ferrites which were prepared by sol-gel route. The detailed results of XRD, SAED and infrared

  8. Preparation and surface characterization of polymer nanoparticles designed for incorporation into hybrid materials.

    PubMed

    Fonseca, T; Relógio, P; Martinho, J M G; Farinha, J P S

    2007-05-01

    We prepared water dispersions of poly(n-butyl methacrylate-st-butyl acrylate) crosslinked core-shell nanoparticles functionalized with different amounts of trimethoxisilane (TMS) groups in the outer shell. The purpose of the TMS groups is to chemically bind the rubbery particles to a nanostructured silica network, using sol-gel copolymerization. Here, we present nanoparticles containing 13 mol % and 30 mol % of TMS groups in the outer shell and compare their surface morphology with particles that do not contain TMS. The particles are prepared by a two-step seeded emulsion polymerization technique at neutral pH. In the first step, we obtained crosslinked seed particles (44 nm in diameter) by a batch process. In the second step, we used a semi-continuous emulsion polymerization technique under starved feed conditions to obtain monodispersed particles of controlled composition and size (ca. 100 nm in diameter). Fluorescence decay measurements were performed in situ on the dispersions, using a pair of cationic dyes adsorbed onto the surface of the nanoparticles: rhodamine 6G as the energy transfer donor and malachite green carbinol hydrochloride as the acceptor. The kinetics of Förster resonance energy transfer (FRET) between the dyes is sensitive to the donor-acceptor distance, allowing us to obtain the binding distribution of the dyes at the nanoparticle surface. For the unmodified nanoparticles, we found a dye distribution that corresponds to an average interface thickness of delta = (5.2 +/- 0.2) nm. For the samples containing 13 mol % and 30 mol % of TMS groups in the outer shell we obtained broader interfaces, with widths of delta = (6.2 +/- 0.2) nm and delta = (6.5 +/- 0.1) nm respectively. This broadening of the distribution with the surface modification is interpreted in terms of the increase in free volume of the shell caused by the TMS groups. Finally, we studied the effect of temperature on the water-polymer interface fuzziness, in order to evaluate the accessibility of the TMS groups during the sol-gel synthesis of nanostructured hybrid materials. PMID:17417887

  9. Structural and optical characterization of tin dioxide nanoparticles prepared by a surfactant mediated method

    SciTech Connect

    Pal, Jagriti, E-mail: shubhriti@gmail.com [Physics Department, University of Allahabad, Allahabad-211002 (India); Chauhan, Pratima, E-mail: mangu167@yahoo.co.in [Physics Department, University of Allahabad, Allahabad-211002 (India)

    2009-12-15

    In this study tin dioxide nanoparticles were synthesized using a cationic surfactant (cetyl-trimethyl ammonium bromide) as the organic template and the hydrous tin chloride and liquid ammonia as the inorganic precursor. Samples were characterized by X-ray diffraction, transmission electron microscopy and UV-visible absorption, photoluminescence and Raman spectroscopy. The X-ray diffraction pattern of the as prepared sample is indexed to rutile phase of tin dioxide without any trace of an extra phase and particle size 7-8 nm which is further confirmed by electron microscopy. The UV-visible spectrum shows that the absorption edge is blue shifted and the band gap of the prepared sample is 4.0 eV which is larger than the bulk tin dioxide (3.6 eV).

  10. Iron oxide nanoparticles embedded in activated carbons prepared from hydrothermally treated waste biomass.

    PubMed

    Hao, Wenming; Björkman, Eva; Yun, Yifeng; Lilliestråle, Malte; Hedin, Niklas

    2014-03-01

    Particles of iron oxide (Fe3O4 ; 20–40 nm) were embedded within activated carbons during the activation of hydrothermally carbonized (HTC) biomasses in a flow of CO2. Four different HTC biomass samples (horse manure, grass cuttings, beer production waste, and biosludge) were used as precursors for the activated carbons. Nanoparticles of iron oxide formed from iron catalyst included in the HTC biomasses. After systematic optimization, the activated carbons had specific surface areas of about 800 m2g1. The pore size distributions of the activated carbons depended strongly on the degree of carbonization of the precursors. Activated carbons prepared from highly carbonized precursors had mainly micropores, whereas those prepared from less carbonized precursors contained mainly mesopores. Given the strong magnetism of the activated carbon–nano-Fe3O4 composites, they could be particularly useful for water purification. PMID:24678001

  11. Preparation of curcumin-loaded pluronic F127/chitosan nanoparticles for cancer therapy

    NASA Astrophysics Data System (ADS)

    Phuc Le, Thi Minh; Phuc Pham, Van; Lua Dang, Thi Minh; Huyen La, Thi; Hanh Le, Thi; Huan Le, Quang

    2013-06-01

    Nanoparticles (NPs) have been proven to be an effective delivery system with few side effects for anticancer drugs. In this study, curcumin-loaded NPs have been prepared by an ionic gelation method using chitosan (Chi) and pluronic®F-127 (PF) as carriers to deliver curcumin to the target cancer cells. Prepared NPs were characterized using Zetasizer, fluorescence microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Our results showed that the encapsulation efficiency of curcumin was approximately 50%. The average size of curcumin-loaded PF/Chi NPs was 150.9 nm, while the zeta potential was 5.09 mV. Cellular uptake of curcumin-loaded NPs into HEK293 cells was confirmed by fluorescence microscopy.

  12. Preparation of an agar-silver nanoparticles (A-AgNp) film for increasing the shelf-life of fruits.

    PubMed

    Gudadhe, Janhavi A; Yadav, Alka; Gade, Aniket; Marcato, Priscyla D; Durán, Nelson; Rai, Mahendra

    2014-12-01

    Preparation of protective coating possessing antimicrobial properties is present day need as they increase the shelf life of fruits and vegetables. In the present study, preparation of agar-silver nanoparticle film for increasing the shelf life of fruits is reported. Silver nanoparticles (Ag-NPs) biosynthesised using an extract of Ocimum sanctum leaves, were mixed with agar-agar to prepare an agar-silver nanoparticles (A-AgNp) film. This film was surface-coated over the fruits, Citrus aurantifolium (Thornless lime) and Pyrus malus (Apple), and evaluated for the determination of antimicrobial activity of A-AgNp films using disc diffusion method, weight loss and shelf life of fruits. This study demonstrates that these A-AgNp films possess antimicrobial activity and also increase the shelf life of fruits. PMID:25429496

  13. Preparation and testing of quaternized chitosan nanoparticles as gene delivery vehicles.

    PubMed

    Li, Guang-Feng; Wang, Jing-Cheng; Feng, Xin-Min; Liu, Zhen-Dong; Jiang, Chao-Yong; Yang, Jian-Dong

    2015-04-01

    The aim of this study was to synthesize a chitosan (CS) derivative, a quaternary ammonium salt crystal called N-2-hydroxypropyl trimethyl ammonium chloride chitosan (HACC), and test a series of HACC and pEGFP-DNA complexes at different weight ratios for their efficiency of gene delivery into human cells. CS was modified with cationic etherifying agent to obtain the CS derivative. Fourier transform infrared spectra were recorded on KBr pellets with a spectrometer. (1)H nuclear magnetic resonance (NMR) spectra of HACC were obtained using a spectrometer. HACC was subsequently used to prepare HACC/DNA complexes at different weight ratios by coacervation method. The resulting particle size and surface charge were assessed by laser light scattering using a zeta potential analyzer. The HACC/DNA complex formation and DNA protection in the nanoparticle complex was investigated by gel mobility shift assay and DNase I protection assay, respectively. The cytotoxicity of HACC and HACC/DNA nanoparticles was evaluated by MTT assay using (mesenchymal stem cell) MSC lines. The nanoscale structure of the particles was obtained by transmission electron microscope (TEM). The FTIR spectrum of HACC showed the characteristic quaternary ammonium group absorption band at 1475 cm(-1), which indicated the presence of quaternary ammonium group. The successful synthesis of HACC was also confirmed by (1)H NMR spectrum. HACC showed good solubility in water and was electropositive. HACC efficiently packed and protected pEGFP-DNA at a weight ratio of 10. With increased weight ratios, the surface charge of the composite particle increased from negative to positive, the average particle size increased, and HACC nanoparticle had a higher carrying efficiency. The nanoparticles released DNA in two distinct phases, and 55 % was released within the first 20 h of solubilization. The nanoparticles under TEM showed circular or oval shapes. The particles exhibited no cytotoxicity against human cells. No significant difference in gene delivery efficiency was detected between HACC/pEGFP-GDNF and liposome/pEGFP-GDNF complexes (33.8 vs. 34 %, P?=?0.363). In this study, HACC was successfully synthesized, and HACC/DNA complex assembled efficiently. HACC showed strong DNA binding affinity and high protection of DNA and was non-cytotoxic to human cells. The particles had appropriate nanostructure, mean diameter, and DNA release time. The results suggest that HACC nanoparticles are a novel tool for efficient and safe gene delivery. PMID:25686559

  14. Preparation of highly uniform Ag/TiO2 and Au/TiO2 supported nanoparticle catalysts by photodeposition.

    PubMed

    Chan, Sze Chi; Barteau, Mark A

    2005-06-01

    Photodeposition of Ag nanoparticles on commercial TiO2 particles and nanoparticles was performed in order to provide direct visualization of the spatial distribution of photoactive sites on sub-micrometer-scale and nanoscale TiO2 particle surfaces and to create materials for potential catalytic applications. HRTEM (high-resolution transmission electron microscopy) and HAADF-STEM (high-angle annular dark-field scanning transmission electron microscopy) were used to characterize these materials. The size and spatial distributions of the Ag nanoparticles on the commercial TiO2 were not uniform; the concentration of Ag was higher on grain boundaries and at the edges of these submicrometer particles. In the case of TiO2 nanoparticles, the size distribution of the Ag nanoparticles deposited was relatively uniform and independent of irradiation time and photon energy. The amount of Ag deposited on TiO2 nanoparticles was at least 6 times higher than that on the commercial samples for comparable irradiation conditions. Compared to the case of Ag photodeposition, the difference in the amount of Au photodeposited on TiO2 particles and nanoparticles was even greater, especially at low precursor concentrations. Photodeposition on TiO2 nanoparticles is suggested as a potential method for the preparation of Au/TiO2 catalysts, as loadings in excess of 10 wt % of uniform 1 nm metal particles were achieved in this work. PMID:15924494

  15. Preparation and efficacy of Newcastle disease virus DNA vaccine encapsulated in chitosan nanoparticles

    PubMed Central

    Zhao, Kai; Zhang, Yang; Zhang, Xiaoyan; Li, Wei; Shi, Ci; Guo, Chen; Dai, Chunxiao; Chen, Qian; Jin, Zheng; Zhao, Yan; Cui, Hongyu; Wang, Yunfeng

    2014-01-01

    Optimal preparation conditions of Newcastle disease virus (NDV) F gene deoxyribonucleic acid (DNA) vaccine encapsulated in chitosan nanoparticles (pFNDV-CS-NPs) were determined. The pFNDV-CS-NPs were prepared according to a complex coacervation method. The pFNDV-CS-NPs were produced with good morphology, high stability, a mean diameter of 199.5 nm, encapsulation efficiency of 98.37%±0.87%, loading capacity of 36.12%±0.19%, and a zeta potential of +12.11 mV. The in vitro release assay showed that the plasmid DNA was sustainably released from the pFNDV-CS-NPs, up to 82.9%±2.9% of the total amount. Cell transfection test indicated that the vaccine expressed the F gene in cells and maintained good bioactivity. Additionally, the safety of mucosal immunity delivery system of the pFNDV-CS-NPs was also tested in vitro by cell cytotoxicity and in vivo by safety test in chickens. In vivo immunization showed that better immune responses of specific pathogen-free chickens immunized with the pFNDV-CS-NPs were induced, and prolonged release of the plasmid DNA was achieved compared to the chickens immunized with the control plasmid. This study lays the foundation for the further development of mucosal vaccines and drugs encapsulated in chitosan nanoparticles. PMID:24426783

  16. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANOPARTICLE MIXED ALCOHOL CATALYSTS

    SciTech Connect

    Seetala V. Naidu; Upali Siriwardane

    2005-05-24

    We have developed and streamlined the experimental systems: (a) Laser-induced solution deposition (LISD) photosynthesis, ball-milling, and chemical synthesis of Fe, Co, and Cu nanoparticle catalysts; (b) Sol-gel method for mesoporous {gamma}-Al{sub 2}O{sub 3}, SiO{sub 2}, hybrid alumina/silica granular supports; (c) Three sol-gel/oil-drop catalyst preparation methods to incorporate metal nanoparticles into mesoporous 1 mm granular supports; (d) Low-cost GC-TCD system with hydrogen as carrier gas for the determination of wide spectrum of alkanes produced during the F-T reactions; and (e) Gas-flow reactor and microchannel reactor for fast screening of catalysts. The LISD method could produce Co, Cu, and Fe (5 nm) nanoparticles, but in milligram quantities. We could produce nanoparticles in gram quantities using high-energy ball milling and chemical synthesis methods. Ball milling gave wide particle size distribution compared to the chemical synthesis method that gave almost uniform size ({approx}5 nm) particles. Metal nanoparticles Cu, Co, Fe, Cu/Co, Cu/Fe and Co/Fe were loaded (2-12 wt%) uniformly into {gamma}-Al{sub 2}O{sub 3}, SiO{sub 2}, or alumina/silica hybrid supports by combined sol-gel/oil-drop methods followed by calcination and hydrogenation steps, prior to syngas FT reaction studies. The properties of metal loaded {gamma}-Al{sub 2}O{sub 3} granules were compared for the two precursors: aluminum tri-sec-butoxide (ALTSB) and aluminum tri-iso-propoxide (ALTIP). The effect of solgel supports alumina, silica, and alumina/silica hybrid were examined on catalytic properties. Metal loading efficiencies for pure metal catalysts increased in the order Co, Cu and Fe in agreement with solubility of metal hydroxides. In case of mixed metals, Co and Cu seams to interfere and reduce Fe metal loading when metal nitrate solutions are used. The solubility differences of metal hydroxides would not allow precise control of metal loading. We have overcome this problem by introducing a novel method of nanoparticle metal oxide co-entrapped sol-gel that gave the highest metal loading with precise control and reproducibility, and greater mechanical strength of granules than the metal nitrate solution co-entrapping and wet impregnation methods. Both, slurry-phase-batch and gas-phase-continuous-flow, reactors were used for syngas conversion reactions. Our investigations of Co and Fe thin film deposited micro-reactors showed higher CO/H{sub 2} conversion for Fe compared to Co. The catalytic activity for CO/H{sub 2} conversion was observed in the increasing order for the nanocatalysts Cu, Co, Fe, Co/Fe, Cu/Co and Cu/Fe in alumina sol-gel support, and Co/Fe showed the highest yield for methane. The optimization of CO/H{sub 2} ratio indicated that 1:1 ratio gave more alkanes distribution in F-T process with Co/Fe (6% each) impregnated on alumina. We could estimate the activity of catalysts (involving Co, Fe) during hydrogenation and after catalytic reaction using magnetization studies. In summary our accomplishments are: (1) Novel chemical methods for the synthesis of (5 nm) Fe, Co, Cu nanoparticles with narrow size distribution. (2) Developing a method of metal oxide nanoparticles addition to alumina/silica sol-gel to control metal loading of pure and mixed metal catalysts compositions in high yields. (3) A low-cost GC-TCD system to analyze wide spectrum of alkanes (F-T reaction products). (4) Fe/Co mixed metal alumina/silica mesoporous catalysts with higher FT activity. (5) Characterizing nanoparticle catalysts and supports for detail understanding of FT-process.

  17. Preparation and evaluation of tilmicosin-loaded hydrogenated castor oil nanoparticle suspensions of different particle sizes.

    PubMed

    Chen, Xiaojin; Wang, Ting; Lu, Mengmeng; Zhu, Luyan; Wang, Yan; Zhou, WenZhong

    2014-01-01

    Three tilmicosin-loaded hydrogenated castor oil nanoparticle (TMS-HCO-NP) suspensions of different particle sizes were prepared with different polyvinyl alcohol surfactant concentrations using a hot homogenization and ultrasonic technique. The in vitro release, in vitro antibacterial activity, mammalian cytotoxicity, acute toxicity in mice, and stability study were conducted to evaluate the characteristics of the suspensions. The in vitro tilmicosin release rate, antibacterial activity, mammalian cytotoxicity, acute toxicity in mice, and stability of the suspensions were evaluated. When prepared with polyvinyl alcohol concentrations of 0.2%, 1%, and 5%, the mean diameters of the nanoparticles in the three suspensions were 920±35 nm, 452±10 nm, and 151±4 nm, respectively. The three suspensions displayed biphasic release profiles similar to that of freeze-dried TMS-HCO-NP powders, with the exception of having a faster initial release. Moreover, suspensions of smaller-sized particles showed faster initial release, and lower minimum inhibitory concentrations and minimum bactericidal concentrations. Time-kill curves showed that within 12 hours, the suspension with the 151 nm particles had the most potent bactericidal activity, but later, the suspensions with larger-sized particles showed increased antibacterial activity. None of the three suspensions were cytotoxic at clinical dosage levels. At higher drug concentrations, all three suspensions showed similar concentration-dependent cytotoxicity. The suspension with the smallest-sized particle showed significantly more acute toxicity in mice, perhaps due to faster drug release. All three suspensions exhibited good stability at 4°C and at room temperature for at least 6 months. These results demonstrate that TMS-HCO-NP suspensions can be a promising formulation for tilmicosin, and that nanoparticle size can be an important consideration for formulation development. PMID:24920902

  18. Preparation and evaluation of tilmicosin-loaded hydrogenated castor oil nanoparticle suspensions of different particle sizes

    PubMed Central

    Chen, Xiaojin; Wang, Ting; Lu, Mengmeng; Zhu, Luyan; Wang, Yan; Zhou, WenZhong

    2014-01-01

    Three tilmicosin-loaded hydrogenated castor oil nanoparticle (TMS-HCO-NP) suspensions of different particle sizes were prepared with different polyvinyl alcohol surfactant concentrations using a hot homogenization and ultrasonic technique. The in vitro release, in vitro antibacterial activity, mammalian cytotoxicity, acute toxicity in mice, and stability study were conducted to evaluate the characteristics of the suspensions. The in vitro tilmicosin release rate, antibacterial activity, mammalian cytotoxicity, acute toxicity in mice, and stability of the suspensions were evaluated. When prepared with polyvinyl alcohol concentrations of 0.2%, 1%, and 5%, the mean diameters of the nanoparticles in the three suspensions were 920±35 nm, 452±10 nm, and 151±4 nm, respectively. The three suspensions displayed biphasic release profiles similar to that of freeze-dried TMS-HCO-NP powders, with the exception of having a faster initial release. Moreover, suspensions of smaller-sized particles showed faster initial release, and lower minimum inhibitory concentrations and minimum bactericidal concentrations. Time-kill curves showed that within 12 hours, the suspension with the 151 nm particles had the most potent bactericidal activity, but later, the suspensions with larger-sized particles showed increased antibacterial activity. None of the three suspensions were cytotoxic at clinical dosage levels. At higher drug concentrations, all three suspensions showed similar concentration-dependent cytotoxicity. The suspension with the smallest-sized particle showed significantly more acute toxicity in mice, perhaps due to faster drug release. All three suspensions exhibited good stability at 4°C and at room temperature for at least 6 months. These results demonstrate that TMS-HCO-NP suspensions can be a promising formulation for tilmicosin, and that nanoparticle size can be an important consideration for formulation development. PMID:24920902

  19. A novel approach for preparation of Y 2O 3:Eu 3+ nanoparticles by microemulsion–microwave heating

    Microsoft Academic Search

    Qi Pang; Jianxin Shi; Yu Liu; Desong Xing; Menglian Gong; Ningsheng Xu

    2003-01-01

    A novel approach for preparation of europium (III)-doped yttrium oxide (Y2O3:Eu3+) nanoparticles by microemulsion–microwave heating was reported in this paper. Y2O3:Eu3+ nanoparticles were successfully obtained by microwave-heating the as-prepared particles of yttrium hydroxide and europium hydroxide, formed in a reaction between Y(NO3)3–Eu(NO3)3 and NH3·H2O in the reverse microemulsion composed of Triton X-100, n-hexanol, cyclohexane and water. Field-emission scanning electron microscopy

  20. Control of the morphology of nanostructured particles prepared by the spray drying of a nanoparticle sol.

    PubMed

    Iskandar, Ferry; Gradon, Leon; Okuyama, Kikuo

    2003-09-15

    The control of the morphology of nanostructured particles prepared by the spray drying of nanoparticle sol was investigated experimentally and the results are qualitatively explained based on available theory. A theoretical analysis indicates that the structural stability of the droplet and the hydrodynamic effects during the drying process play important roles in controlling the morphology of the resulting particles. The size of the sol in the droplet, droplet size, viscosity of droplet, drying temperature, gas flow rate, and addition of surfactant are all crucial parameters that affect the morphology of particles. Experimentally, nanostructured silica particles were prepared from a nanosize silica sol under various preparation conditions. Doughnut-shaped particles can be produced when the droplet size is large, in conjunction with high temperature, high gas flow rate and in the presence of an added surfactant. Appropriate choice of the spray drying method permits control of the particle size and shape, ranging from spheres to ellipsoids as well as doughnut-shaped particles by varying the preparation conditions. The results open a new route to controlling the formation of a wide variety of nanostructured particles. PMID:12962663

  1. Amino acid mediated synthesis of silver nanoparticles and preparation of antimicrobial agar/silver nanoparticles composite films.

    PubMed

    Shankar, Shiv; Rhim, Jong-Whan

    2015-10-01

    Silver nanoparticles (AgNPs) were synthesized using amino acids (tyrosine and tryptophan) as reducing and capping agents, and they were incorporated into the agar to prepare antimicrobial composite films. The AgNPs solutions exhibited characteristic absorption peak at 420nm that showed a red shift to ?434nm after forming composite with agar. XRD data demonstrated the crystalline structure of AgNPs with dominant (111) facet. Apparent surface color and transmittance of agar films were greatly influenced by the AgNPs. The incorporation of AgNPs into agar did not exhibit any change in chemical structure, thermal stability, moisture content, and water vapor permeability. The water contact angle, tensile strength, and modulus decreased slightly, but elongation at break increased after AgNPs incorporation. The agar/AgNPs nanocomposite films possessed strong antibacterial activity against Listeria monocytogenes and Escherichia coli. The agar/AgNPs film could be applied to the active food packaging by controlling the food-borne pathogens. PMID:26076636

  2. Nanoparticles prepared by the sol gel method and their use in the formation of nanocomposites with polypropylene

    NASA Astrophysics Data System (ADS)

    Moncada, E.; Quijada, R.; Retuert, J.

    2007-08-01

    Hybrid layered aluminosilicate nanoparticles (HLNP) containing octadecylamine (ODA) as the organic part, and silica nanoparticles with spherical morphology containing ODA (HSNP) or without ODA (SNP) were prepared by the sol-gel method and used for the formation of nanocomposites with polypropylene. The polypropylene matrices, of different molecular weight and polydispersity, were prepared using polymers obtained via Ziegler-Natta or metallocene catalysts. A strong influence of the morphology and the presence of ODA on the surface of the nanoparticles was found on the formation and characteristics of the nanocomposites. The mechanical properties and thermal stability of these materials were determined and compared with those of nanocomposites prepared with 2:1 phylosilicate clays such as montmorillonite and hectorite in similar polymer matrices. X-ray diffraction, transmission electron microscopy, and the study of mechanical properties showed that the use of HLNP allows nanocomposites with considerably improved mechanical properties to be obtained, compared with nanocomposites prepared with exfoliated clays. In the case of nanocomposites prepared with spherical particles functionalized with ODA (HSNP), materials with high specific strength combined with high elongation before rupture were obtained. The thermal stabilization of polypropylene matrices containing the synthesized nanoparticles (HLNP, HSNP or SNP) occurs about 50 °C higher than that attained with clays.

  3. Microstructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Ding, Zui; Zhao, Xiruo; Wu, Sizhu; Li, Feng; Yue, Ming; Liu, J. Ping

    2015-05-01

    Three kinds of spinel ferrite nanocrystals, MFe2O4 (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH4) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (Ms). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.

  4. Methods of preparation and modification of advanced zero-valent iron nanoparticles, their properties and application in water treatment technologies

    NASA Astrophysics Data System (ADS)

    Filip, Jan; Kašlík, Josef; Med?ík, Ivo; Petala, Eleni; Zbo?il, Radek; Slunský, Jan; ?erník, Miroslav; Stav?lová, Monika

    2014-05-01

    Zero-valent iron nanoparticles are commonly used in modern water treatment technologies. Compared to conventionally-used macroscopic iron or iron microparticles, the using of nanoparticles has the advantages given mainly by their generally large specific surface area (it drives their high reactivity and/or sorption capacity), small dimensions (it allows their migration e.g. in ground water), and particular physical and chemical properties. Following the applications of zero-valent iron particles in various pilot tests, there arose several critical suggestions for improvements of used nanomaterials and for development of new generation of reactive nanomaterials. In the presentation, the methods of zero-valent iron nanoparticles synthesis will be summarized with a special attention paid to the thermally-induced solid-state reaction allowing preparation of zero-valent iron nanoparticles in an industrial scale. Moreover, the method of thermal reduction of iron-oxide precursors enables to finely tune the critical parameters (mainly particle size and morphology, specific surface area, surface chemistry of nanoparticles etc.) of resulting zero-valet iron nanoparticles. The most important trends of advanced nanoparticles development will be discussed: (i) surface modification of nanomaterilas, (ii) development of nanocomposites and (iii) development of materials for combined reductive-sorption technologies. Laboratory testing of zero-valent iron nanoparticles reactivity and migration will be presented and compared with the field observations: the advanced zero-valent iron nanoparticles were used for groundwater treatment at the locality contaminated by chlorinated hydrocarbons (VC, DCE, TCE and PCE) and reacted nanoparticles were extracted from the sediments for their fate assessment. The authors gratefully acknowledge the support by the Technology Agency of the Czech Republic "Competence Centres" (project No. TE01020218) and the EU FP7 (project NANOREM).

  5. Novel core-shell magnetic nanoparticles for Taxol encapsulation in biodegradable and biocompatible block copolymers: preparation, characterization and release properties.

    PubMed

    Filippousi, Maria; Papadimitriou, Sofia A; Bikiaris, Dimitrios N; Pavlidou, Eleni; Angelakeris, Mavroeidis; Zamboulis, Dimitris; Tian, He; Van Tendeloo, Gustaaf

    2013-05-01

    Theranostic polymeric nanocarriers loaded with anticancer drug Taxol and superparamagnetic iron oxide nanocrystals have been developed for possible magnetic resonance imaging (MRI) use and cancer therapy. Multifunctional nanocarriers with a core-shell structure have been prepared by coating superparamagnetic Fe3O4 nanoparticles with block copolymer of poly(ethylene glycol)-b-poly(propylene succinate) with variable molecular weights of the hydrophobic block poly(prolylene succinate). The multifunctional polymer nano-vehicles were prepared using a nanoprecipitation method. Scanning transmission electron microscopy revealed the encapsulation of magnetic nanoparticles inside the polymeric matrix. Energy dispersive X-ray spectroscopy and electron energy loss spectroscopy mapping allowed us to determine the presence of the different material ingredients in a quantitative way. The diameter of the nanoparticles is below 250 nm yielding satisfactory encapsulation efficiency. The nanoparticles exhibit a biphasic drug release pattern in vitro over 15 days depending on the molecular weight of the hydrophobic part of the polymer matrix. These new systems where anti-cancer therapeutics like Taxol and iron oxide nanoparticles (IOs) are co-encapsulated into new facile polymeric nanoparticles, could be addressed as potential multifunctional vehicles for simultaneous drug delivery and targeting imaging as well as real time monitoring of therapeutic effects. PMID:23524084

  6. Facile preparation of TiO2-polyvinyl alcohol hybrid nanoparticles with improved visible light photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Filippo, Emanuela; Carlucci, Claudia; Capodilupo, Agostina Lina; Perulli, Patrizia; Conciauro, Francesca; Corrente, Giuseppina Anna; Gigli, Giuseppe; Ciccarella, Giuseppe

    2015-03-01

    Hybrid inorganic/organic core/shell nanoparticles were prepared through a two step synthesis procedure. In the first step, pure anatase TiO2 nanoparticles were synthesized though a rapid microwave assisted non-aqueous route. Then, the obtained titania nanoparticles were coated with polyvinyl alcohol (PVA) using a simple solution method followed by relatively low temperature treatment. The PVA-coated titania nanoparticles samples were prepared at different TiO2-PVA weight ratio and they were characterized using X-Ray diffraction, transmission electron microscopy, infrared spectroscopy and Brunauer-Emmett-Teller (BET) analysis. Photocatalytic performance was also evaluated for all samples and the results indicated that TiO2:PVA weight ratio was a key factor to obtain an improvement of the photocatalytic activity with respect to bare TiO2 nanoparticles, since PVA concentration influenced the surface area and the aggregation of nanoparticles and the thickness of the coating layer. This inexpensive system provides a simple, quick and effective approach which allows to obtain core/shell hybrid nanostructures.

  7. Preparation and Properties of Nanoparticles of Calcium Phosphates With Various Ca/P Ratios

    PubMed Central

    Sun, Limin; Chow, Laurence C.; Frukhtbeyn, Stanislav A.; Bonevich, John E.

    2010-01-01

    This study aimed at preparing and studying the properties of nanoparticles of calcium phosphate (nCaP) with Ca/P ratios ranging from 1.0 to 1.67 using a spray-drying technique. Micro-structural analyses suggested that the nCaPs with Ca/P ratios of 1.67 to 1.33 were nano-sized amorphous calcium phosphate (ACP) containing varying amounts of acid phosphate and carbonate. The nCaP with Ca/P ratio of 1 contained only nano-sized low crystalline dicalcium phosphate (DCP). BET measurements of the nCaPs showed specific surface areas of (12 ± 2 to 50 ± 1) m2/g, corresponding to estimated equivalent spherical diameters of (38 to 172) nm. However, dynamic light scattering measurements revealed much larger particles of (380 ± 49 to 768 ± 111) nm, owing to agglomeration of the smaller primary nano particles as revealed by Scanning Electron Microscopy (SEM). Thermodynamic solubility measurements showed that the nCaPs with Ca/P ratio of 1.33 – 1.67 all have similar solubility behavior. The materials were more soluble than the crystalline hydroxyapatite (HA) at pH greater than about 4.7, and more soluble than ?-tricalcium phosphate (?-TCP), octacalcium phosphate (OCP) and DCP at pH above 5.5. Their solubility approached that of ?-tricalcium phosphate (?-TCP) at about pH 7. These nCaPs, which cannot be readily prepared by other currently available methods for nanoparticle preparation, have potential biomedical applications. PMID:21037948

  8. 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

  9. A preliminary ferritic-martensitic stainless steel constitution diagram

    SciTech Connect

    Balmforth, M.C.; Lippold, J.C. [Ohio State Univ., Columbus, OH (United States). Welding and Joining Metallurgy Group

    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.

  10. Preparation of carboxylated Ag nanoparticles as a coating material for medical devices and control of antibacterial activity.

    PubMed

    Furuzono, Tsutomu; Iwamoto, Takashi; Azuma, Yoshinao; Okada, Masahiro; Sawa, Yoshiki

    2013-12-01

    Carboxyl group-donated silver (Ag) nanoparticles for coating on medical devices were prepared by a two-phase reduction system in situ. AgNO3 was the Ag ion source, tetraoctylammonium bromide [N(C8H17)4Br] the phase-transfer agent, sodium tetrahydroborate (NaBH4) the reducing agent and 10-carboxy-1-decanthiol (C11H22O2S, CDT) the capping agent. The characterizations of the Ag nanoparticles were conducted by diffuse reflectance Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric differential thermal analysis (TG/DTA) and transmission electron microscope. With CDT capped on Ag nanoparticles, we found that the band around 3,100 cm(-1) was attributed to COO-H stretching vibration, two adsorptions at 2,928 and 2,856 cm(-1) to C-H symmetric/anti-symmetric stretching vibration, and at 1,718 cm(-1) to C=O stretching vibration in the FT-IR spectra. The organic components of the carboxylated Ag nanoparticles were 5.8-25.9 wt%, determined by TG/DTA. The particle sizes of the carboxylated Ag nanoparticles were well controlled by the addition of the capping agent, CDT, into the reaction system. The antimicrobial activity of the Ag nanoparticles covered with different contents of CDT against E. coli was evaluated. Smaller-size Ag nanoparticles showed higher antibacterial activity, which depended on a surface area that attached easily to a microorganism cell membrane. PMID:23793975

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

    E-print Network

    Liu, J. Ping

    and corrosion resis- tivity [1­3], have made them popular for industrial application such as microwave device3 þ in different sites with other suitable ions, such as Cu2 þ [8], Cr3 þ [9,10], Ga3 þ [11], Ti4 þ

  12. Preparation and characterization of self-assembled chitosan nanoparticles for the sustained delivery of streptokinase: an in vivo study.

    PubMed

    Modaresi, Seyed Mohamad Sadegh; Ejtemaei Mehr, Shahram; Faramarzi, Mohammad Ali; Esmaeilzadeh Gharehdaghi, Elina; Azarnia, Mahnaz; Modarressi, Mohammad Hossein; Baharifar, Hadi; Vaez, Seyed Javad; Amani, Amir

    2014-08-01

    Chitosan (CS) nanoparticles have been extensively studied as carriers for therapeutic proteins in recent years. In this study, streptokinase loaded-CS nanoparticles were prepared and the pharmacokinetic parameters of streptokinase were compared with those of naked streptokinase. The preparation method included stirring the protein with the CS solution. The optimized combination was used for animal experiments to determine the streptokinase activity in rat plasma. Blood samples were collected at specified intervals and the activity assay was performed based on amidolysis activity of the chromogenic substrate, S2251, by streptokinase-plasminogen activator complex. The results demonstrated that streptokinase-loaded CS nanoparticles have more prolonged amidolytic activity in vivo compared to the naked one. PMID:23859703

  13. Physical properties of nanoparticle silica gel doped with CdS prepared by sol-gel technique

    Microsoft Academic Search

    I. K. Battisha

    2002-01-01

    CdS\\/silica xerogel glasses were prepared via silica gels containing mixture solution of 0.2 M (CdCl2 and thiourea) with molar ratio 1:1. Doping the gels with this mixture solution and its heat treatment gave transparent yellow silica-gel glasses doped with CdS crystals. X-ray diffraction and transmission electron microscope make it possible to evaluate the nanoparticle size of the prepared samples. The

  14. Core-shell magnesium hydroxide\\/polystyrene hybrid nanoparticles prepared by ultrasonic wave-assisted in-situ copolymerization

    Microsoft Academic Search

    Shengpeng Liu; Jiru Ying; Xingping Zhou; Xiaolin Xie

    2009-01-01

    In this paper, vinylated magnesium hydroxide (MH) nanosheets were prepared with 3-(trimethoxysilyl) propyl methacrylate (?-MPS) and pristine MH nanosheets, then the MH\\/polystyrene (PS) hybrid nanoparticles were prepared by ultrasonic wave-assisted in-situ copolymerization of vinylated MH nanosheets and styrene (St). The morphology, thermal stability and chemical structure of the final products were investigated in detail with transmission electron microscopy (TEM), scanning

  15. Research paper Preparation, characterization and in vivo evaluation of amorphous atorvastatin calcium nanoparticles using supercritical antisolvent (SAS) process

    Microsoft Academic Search

    Min-Soo Kim; Shun-Ji Jin; Jeong-Soo Kim; Hee Jun Park; Ha-Seung Song; Reinhard H. H. Neubert; Sung-Joo Hwang

    In this work, amorphous atorvastatin calcium nanoparticles were successfully prepared using the supercritical antisolvent (SAS) pro- cess. The effect of process variables on particle size and distribution of atorvastatin calcium during particle formation was investigated. Solid state characterization, solubility, intrinsic dissolution, powder dissolution studies and pharmacokinetic study in rats were per- formed. Spherical particles with mean particle size ranging between

  16. Preparation of fluorescent mesoporous hollow silica-fullerene nanoparticles via selective etching for combined chemotherapy and photodynamic therapy.

    PubMed

    Yang, Yannan; Yu, Meihua; Song, Hao; Wang, Yue; Yu, Chengzhong

    2015-07-28

    Well-dispersed mesoporous hollow silica-fullerene nanoparticles with particle sizes of ?50 nm have been successfully prepared by incorporating fullerene molecules into the silica framework followed by a selective etching method. The fabricated fluorescent silica-fullerene composite with high porosity demonstrates excellent performance in combined chemo/photodynamic therapy. PMID:26041655

  17. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  18. Tailored conductivity behavior in nanocrystalline nickel ferrite

    Microsoft Academic Search

    Babita Baruwati; K. Madhusudan Reddy; Sunkara V. Manorama; Rajnish K. Singh; Om Parkash

    2004-01-01

    In this letter, we report an important issue in nanoparticle synthesis by the ``bottom up'' approach. By controlling the pH of the starting mixture of the salts we have been successful in obtaining the desired conductivity of nanosized nickel ferrite. X-ray diffraction and transmission electron microscopy confirmed the size, structure, and morphology of the nanoferrites. All the materials are typical

  19. Preparation, characterization and evaluation of biocomposite films containing chitosan and sago starch impregnated with silver nanoparticles.

    PubMed

    Arockianathan, P Marie; Sekar, S; Kumaran, B; Sastry, T P

    2012-05-01

    The positive attributes of excellent biocompatibility and biodegradability of biopolymers with versatile biological activities have provided ample opportunities for further development of functional biomaterials of high potential in various fields. The biopolymers used in this study, i.e. chitosan and sago starch are abundantly available in nature and can be used in various biomedical applications. In the present study, the composite films of chitosan (Ch) and sago starch (SG) impregnated with silver nanoparticles (AgNP) with and without antibiotic gentamicin (G) were prepared by solvent casting method. The films prepared were characterized for their physic-chemical properties using conventional methods. The results obtained showed that with the increase of chitosan content in the composite results in decrease in its water absorption capacity. The FTIR and SEM studies have shown the composite nature of the films prepared. Ch-SG-AgNP and Ch-SG-AgNP-G composites were used as wound dressing materials in experimental wounds of rats. The healing pattern of the wounds was evaluated by planimetric studies, macroscopic observations, biochemical studies and histopathological observations. The results have shown faster healing pattern in the wounds treated with Ch-SG-AgNP and Ch-SG-AgNP-G composites compared to untreated control. This study suggests that Ch-SG-AgNP film may be a potential candidate as a dressing material for wound healing applications. PMID:22390849

  20. Preparation and characterization of poly(DL-lactide-co-glycolide) nanoparticles for siRNA delivery.

    PubMed

    Cun, Dongmei; Foged, Camilla; Yang, Mingshi; Frøkjaer, Sven; Nielsen, Hanne Mørck

    2010-05-01

    Synthetic short interfering RNA (siRNA) is promising for specific and efficient knockdown of disease-related genes. However, in vivo application of siRNA requires an effective delivery system. Commonly used siRNA carriers are based on polycations, which form electrostatic complexes with siRNA. Such poly- or lipoplexes are of limited use in vivo due to severe problems associated with toxicity, serum instability and non-specific immune-responses. The aim of the present study was to prepare uniformly sized nanoparticles (NPs) with a high load of siRNA by use of the safe and biodegradable poly-(DL-lactide-co-glycolide) (PLGA) polymer without including polycations. The siRNA was encapsulated in the core of NPs by the double emulsion solvent evaporation method. To optimize the NP formulation, the effects of important formulation and processing parameters were investigated systematically. Generally, spherical siRNA-loaded NPs (<300 nm, PDI<0.2, zeta potential -40 mV) were obtained. An encapsulation efficiency of up to 57% was achieved by adjusting the inner water phase volume, the PLGA concentration, the first emulsification sonication time, and stabilization of the water-oil interface with serum albumin. The integrity of siRNA was preserved during the preparation. Preparation of core-loaded siRNA-NPs based on PLGA and no cationic excipient seems possible and promising for delivery of siRNA. PMID:19836438

  1. Facile preparation of paclitaxel loaded silk fibroin nanoparticles for enhanced antitumor efficacy by locoregional drug delivery.

    PubMed

    Wu, Puyuan; Liu, Qin; Li, Rutian; Wang, Jing; Zhen, Xu; Yue, Guofeng; Wang, Huiyu; Cui, Fangbo; Wu, Fenglei; Yang, Mi; Qian, Xiaoping; Yu, Lixia; Jiang, Xiqun; Liu, Baorui

    2013-12-11

    Non-toxic, safe materials and preparation methods are among the most important factors when designing nanoparticles (NPs) for future clinical application. Here we report a novel and facile method encapsulating anticancer drug paclitaxel (PTX) into silk fibroin (SF), a biocompatible and biodegradable natural polymer, without adding any toxic organic solvents, surfactants or other toxic agents. The paclitaxel loaded silk fibroin nanoparticles (PTX-SF-NPs) with a diameter of 130 nm were formed in an aqueous solution at room temperature by self-assembling of SF protein, which demonstrated mainly silk I conformation in the NPs. In cellular uptake experiments, coumarin-6 loaded SF NPs were taken up efficiently by two human gastric cancer cell lines BGC-823 and SGC-7901. In vitro cytotoxicity studies demonstrated that PTX kept its pharmacological activity when incorporating into PTX-SF-NPs, while SF showed no cytotoxicity to cells. The in vivo antitumor effects of PTX-SF-NPs were evaluated on gastric cancer nude mice exnograft model. We found that locoregional delivery of PTX-SF-NPs demonstrated superior antitumor efficacy by delaying tumor growth and reducing tumor weights compared with systemic administration. Furthermore, the organs of mice in NP treated groups didn't show obvious toxicity, indicating the in vivo safety of SF NPs. These results suggest that SF NPs are promising drug delivery carriers, and locoregional delivery of SF NPs could be a potential future clinical cancer treatment regimen. PMID:24274601

  2. Interaction of bovine serum albumin with starch nanoparticles prepared by TEMPO-mediated oxidation.

    PubMed

    Fan, Haoran; Ji, Na; Zhao, Mei; Xiong, Liu; Sun, Qingjie

    2015-07-01

    The objective of this study was to elucidate the interaction of starch nanoparticles prepared through TEMPO oxidation (TEMPO-SNPs) with protein (bovine serum albumin) by various spectroscopic techniques and transmission electron microscopy (TEM). The enhanced absorbance observed by UV spectra and the decrease in fluorescence spectroscopy of bovine serum albumin (BSA) induced by TEMPO-SNPs demonstrated the occurrence of an interaction between BSA and TEMPO-SNPs. The quenching constant was inversely correlated with temperature, showing that the quenching effect of TEMPO-SNPs was static quenching. Electrostatic force had a leading contribution to the binding roles of BSA on TEMPO-SNPs, which was confirmed by negative enthalpy change and positive entropy change. When interacting with TEMPO-SNPs at different concentrations, the content of the ?-helix structure in BSA decreased and ?-sheet and random coil structures increased, indicating that TEMPO-SNPs had an effect on the secondary conformation of BSA. Furthermore, TEM images suggested that nanoparticle-protein complexes were formed. PMID:25907012

  3. Silver nanoparticles supported on passivated silica: preparation and catalytic performance in alkyne semi-hydrogenation.

    PubMed

    Oakton, Emma; Vilé, Gianvito; Levine, Daniel S; Zocher, Eva; Baudouin, David; Pérez-Ramírez, Javier; Copéret, Christophe

    2014-10-28

    Herein, we report the preparation of small and narrowly distributed (2.1 ± 0.5 nm) Ag nanoparticles supported on passivated silica, where the surface OH groups are replaced by OSiMe3 functionalities. This synthetic method involves the grafting of silver(I) bis(trimethylsilyl)amide ([AgN(SiMe3)2]4) on silica partially dehydroxylated at 700 °C, followed by a thermal treatment of the grafted complex under H2. The catalytic performance of this material was investigated in the semi-hydrogenation of propyne and 1-hexyne and compared with that of 2.0 ± 0.3 nm Ag nanoparticles supported on silica. Whilst surface passivation slightly decreases the activity in both reactions (by a factor 2-3), probably as a result of the decreased alkyne adsorption properties or the presence of less accessible active sites on the passivated support, the AgNP@SiO2 catalysts demonstrate a remarkable selectivity for the production of alkenes. PMID:25178410

  4. Preparation and characterization of starch nanoparticles through ultrasonic-assisted oxidation methods.

    PubMed

    Sun, Qingjie; Fan, Haoran; Xiong, Liu

    2014-06-15

    In this work, starch nanoparticles (SNPs) were prepared from waxy corn starch (WCS) through ultrasonic-assisted oxidation. Three SNPs samples were produced by one time oxidation followed by ultrasonic treatment (O1U1-SNPs), twice oxidation and twice ultrasonic treatment (O2U2-SNPs) and TEMPO-mediated oxidation with ultrasonic treatment (TEMPO-SNPs), respectively. Differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the thermal properties, morphology, and structure of the ensuing nanoparticles. The results revealed that the size of the O1U1-SNPs, O2U2-SNPs, and TEMPO-SNPs particles reached 30-50 nm, 20-50 nm and 20-60 nm, respectively. Compared to WCS, the crystallinity of the O1U1-SNPs, O2U2-SNPs and TEMPO-SNPs samples decreased from 36.32% to 11.35%, 1.64% and 1.72%, respectively. The O1U1-SNPs, O2U2-SNPs and TEMPO-SNPs exhibited smaller or no endotherms. The SNPs had higher carboxyl and carbonyl content. PMID:24721090

  5. Stratified assemblies of magnetite nanoparticles and montmorillonite prepared by the layer-by-layer assembly

    SciTech Connect

    Mamedov, A.; Ostrander, J.; Aliev, F.; Kotov, N.A.

    2000-04-18

    Hybrid thin films are prepared from 8 to 10 nm Fe{sub 3}O{sub 4} nanoparticles and exfoliated montmorillonite clay by using layer-by-layer assembly on poly(diallyldimethylammonium bromide), PDDA. Distinct stratification of the Fe{sub 3}O{sub 4}/PDDA/clay films is obtained due to the sheetlike structure of the clay particles. This feature distinguishes these assemblies from their polyelectrolyte-polyelectrolyte analogues, where the layers of individual polyelectrolytes are strongly interdigitated. Being adsorbed on PDDA strictly parallel to the substrate surface, montmorillonite produces a dense layer of overlapping alumosilicate sheets, which virtually flawlessly separates one magnetite layer from another. The difference in magnetic properties between assemblies of various architectures is attributed to the insulation effect of clay layers inserted between magnetic layers. The montmorillonite sheets disrupt the electron exchange interactions between the magnetite nanoparticles in adjacent layers, thereby limiting the magnetization reversal to two dimensions. Some optical properties of Fe{sub 3}O{sub 4}/PDDA films are investigated as well. When they are deposited on thin plastic substrate, oscillations of optical density were observed in the red part of the UV-vis spectrum. This effect, which has never been observed for conventional, thick substrates such as glass slides, stems from the interference of the light beams passed through and reflected off of the assembled film.

  6. Antibacterial continuous nanofibrous hybrid yarn through in situ synthesis of silver nanoparticles: preparation and characterization.

    PubMed

    Barani, Hossein

    2014-10-01

    Nanofibrous hybrid yarns of polyvinyl alcohol (PVA) and poly-l-lactide acid (PLLA) with the antibacterial activity were prepared that contains 0, 5, 10, 20, and 30 wt.% of silver nanoparticles according to the PVA polymer content. This was performed by electrospinning using distilled water and 2, 2, 2-trifluoroethanol as a solvent for PVA and PLLA respectively, and sodium borohydride was used as a reducing agent. The scanning electron microscope observation confirmed the formation of AgNPs into the PVA nanofiber structure, and they were uniform, bead free, cylindrical and smooth. The diameter of hybrid yarns and their nanofiber component was decreased as the silver nitrate concentration in electrospinning solutions was increased. The differential scanning calorimetry results indicated that the silver nanoparticles can form interactions with polymer chains and decrease the melting enthalpy. The mechanical analysis showed a lower stress and strain at break of the AgNP-loaded nanofibrous hybrid yarns than the unloaded hybrid yarn. However, there wasn't a statistically significant difference between the strain at break of electrospun nanofibrous hybrid yarns. Moreover, the bactericidal efficiency of all loaded samples was over 99.99%. PMID:25175187

  7. Characterization and antimicrobial activity of silver nanoparticles prepared by a thermal decomposition technique

    NASA Astrophysics Data System (ADS)

    Tam, Le Thi; Phan, Vu Ngoc; Lan, Hoang; Thuy, Nguyen Thanh; Hien, Tran Minh; Huy, Tran Quang; Quy, Nguyen Van; Chinh, Huynh Dang; Tung, Le Minh; Tuan, Pham Anh; Lam, Vu Dinh; Le, Anh-Tuan

    2013-11-01

    Recently, there has been an increasing need of efficient synthetic protocols using eco-friendly conditions including low costs and green chemicals for production of metal nanoparticles. In this work, silver nanoparticles (silver NPs) with average particle size about 10 nm were synthesized by using a thermal decomposition technique. Unlike the colloidal chemistry method, the thermal decomposition method developed has advantages such as the high crystallinity, single-reaction synthesis, and easy dispersion ability of the synthesized NPs in organic solvents. In a modified synthesis process, we used sodium oleate as a capping agent to modify the surface of silver NPs because the oleate has a C18 tail with a double bond in the middle, therefore, forming a kink which is to be effective for aggregative stability. Importantly, the as-synthesized silver NPs have demonstrated strong antimicrobial effects against various bacteria and fungi strains. Electron microscopic studies reveal physical insights into the interaction and bactericidal mechanism between the prepared silver NPs and tested bacteria in question. The observed excellent antibacterial and antifungal activity of the silver NPs make them ideal for disinfection and biomedicine applications.

  8. Improvement of mechanical durability on organic TFT with printed electrodes prepared from nanoparticle ink

    NASA Astrophysics Data System (ADS)

    Sekine, Tomohito; Ikeda, Hideaki; Kosakai, Akifumi; Fukuda, Kenjiro; Kumaki, Daisuke; Tokito, Shizuo

    2014-03-01

    We investigated a mechanism of improving adhesiveness depending on sintering temperature for printed silver (Ag) electrodes prepared from nanoparticle ink on an insulating polymer layer as the under layer. The adhesion strength significantly improved by sintering the Ag electrodes at a temperature above the glass transition temperature (Tg) of the polymer layer. In the sample with improved adhesiveness, the interfacial fusion between the printed Ag electrodes and polymer layer was observed in a cross sectional scanning electron microscope image. Based on this mechanism, we have successfully demonstrated the improvement in mechanical durability of organic thin-film transistors (TFTs) with printed Ag electrodes. The degradation of the organic TFTs after applying bending stress was significantly suppressed by interfacial fusion.

  9. The convenient preparation of stable aryl-coated zerovalent iron nanoparticles

    PubMed Central

    Guselnikova, Olga A; Galanov, Andrey I; Gutakovskii, Anton K

    2015-01-01

    Summary A novel approach for the in situ synthesis of zerovalent aryl-coated iron nanoparticles (NPs) based on diazonium salt chemistry is proposed. Surface-modified zerovalent iron NPs (ZVI NPs) were prepared by simple chemical reduction of iron(III) chloride aqueous solution followed by in situ modification using water soluble arenediazonium tosylate. The resulting NPs, with average iron core diameter of 21 nm, were coated with a 10 nm thick organic layer to provide long-term protection in air for the highly reactive zerovalent iron core up to 180 °C. The surface-modified iron NPs possess a high grafting density of the aryl group on the NPs surface of 1.23 mmol/g. FTIR spectroscopy, XRD, HRTEM, TGA/DTA, and elemental analysis were performed in order to characterize the resulting material.

  10. Preparation of a silicon heterojunction photodetector from colloidal indium oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Ismail, Raid A.; Ali, Abdulrahman K.; Hassoon, Khaleel I.

    2013-10-01

    A colloidal indium oxide (In2O3) nanoparticles (NPs) were synthesized by using a Q-switched Nd:YAG laser ablation of indium target in water at room temperature. Optical absorption and x-ray diffraction (XRD) investigation of the prepared samples confirm the formation of In2O3 NPs. A solution-processed silicon heterojunction photodetector, fabricated by drop cast film of colloidal In2O3 NPs onto n-type single crystal silicon wafer, is demonstrated. I-V characteristics of In2O3 NPs/Si heterojunction under dark and illumination conditions confirmed the rectifying behavior and the good photoresponse. The built-in-voltage was determined from the C-V measurements which revealed an abrupt junction.

  11. Controllable preparation and properties of composite materials based on ceria nanoparticles and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Li, Changqing; Sun, Nijuan; Ni, Jiangfeng; Wang, Jinyong; Chu, Haibin; Zhou, Henghui; Li, Meixian; Li, Yan

    2008-10-01

    We report a method to prepare composites based on carbon nanotubes (CNTs) and CeO 2 nanoparticles (NPs). The CeO 2 NPs were attached to CNTs by hydrothermal treatment of Ce(OH) 4/CNT mixture in NaOH solution at 180 °C. It was found that larger CeO 2 NPs were formed in the presence of CNTs. Grain size of CeO 2 NPs in the composites can be reduced when NaNO 3 was added in the hydrothermal process. Electrochemical characterizations have shown that the composites possess a specific capacity between those of CNTs and CNTs mechanically mixed with CeO 2. These CeO 2/CNT composites could serve as promising anode materials for Li-ion batteries.

  12. Preparation of uranium fuel kernels with silicon carbide nanoparticles using the internal gelation process

    NASA Astrophysics Data System (ADS)

    Hunt, R. D.; Silva, G. W. C. M.; Lindemer, T. B.; Anderson, K. K.; Collins, J. L.

    2012-08-01

    The US Department of Energy continues to use the internal gelation process in its preparation of tristructural isotropic coated fuel particles. The focus of this work is to develop uranium fuel kernels with adequately dispersed silicon carbide (SiC) nanoparticles, high crush strengths, uniform particle diameter, and good sphericity. During irradiation to high burnup, the SiC in the uranium kernels will serve as getters for excess oxygen and help control the oxygen potential in order to minimize the potential for kernel migration. The hardness of SiC required modifications to the gelation system that was used to make uranium kernels. Suitable processing conditions and potential equipment changes were identified so that the SiC could be homogeneously dispersed in gel spheres. Finally, dilute hydrogen rather than argon should be used to sinter the uranium kernels with SiC.

  13. Sonochemically synthesis of pyrazolones using reusable catalyst CuI nanoparticles that was prepared by sonication.

    PubMed

    Ziarati, Abolfazl; Safaei-Ghomi, Javad; Rohani, Sahar

    2013-07-01

    A simple and green process to prepare copper iodide in nano scale via sonication was carried out. Subsequently, this nanoparticles was used as an efficient catalyst for the synthesis of 2-aryl-5-methyl-2,3-dihydro-1H-3-pyrazolones via four-component reaction of hydrazine, ethyl acetoacetate, aldehyde and ?-naphthol in water under ultrasound irradiation. The combinatorial synthesis was attained for this procedure with applying ultrasound irradiation while making use of water as green ambient. Simple work-up, excellent yield of products and short reaction times are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for five times without noticeably decreasing the catalytic activity. PMID:23414833

  14. Temporal and preparation effects in the magnetic nanoparticles of Apis mellifera body parts

    NASA Astrophysics Data System (ADS)

    Chambarelli, L. L.; Pinho, M. A.; Abraçado, L. G.; Esquivel, D. M. S.; Wajnberg, E.

    Magnetic nanoparticles in the Apis mellifera abdomens are well accepted as involved in their magnetoreception mechanism. The effects of sample preparation on the time evolution of magnetic particles in the honeybee body parts (antennae, head, thorax and abdomen) were investigated by Ferromagnetic Resonance (FMR) at room temperature (RT), for about 100 days. Three preparations were tested: (a) washed with water (WT); (b) as (a), kept in glutaraldehyde 2.5% in 0.1 M cacodylate buffer (pH 7.4) for 24 h and washed with cacodylate buffer (C); (c) as (a), kept in glutaraldehyde 2.5% for 24 h and washed with glutaraldehyde 2.5% in cacodylate buffer (GLC). The four body parts of young and adult worker presented magnetic nanoparticles. The Mn 2+ lines are observed except for the antennae spectra. The high field (HF) and low field (LF) components previously observed in the spectra of social insects, are confirmed in these spectra. The HF line is present in all spectra while the LF is easily observed in the spectra of the young bee and it appears as a baseline shift in spectra of some adult parts. The HF intensity of the abdomen is commonly one order of magnitude larger than any other body parts. This is the first systematic study on the conservation of magnetic material in all body parts of bees. The results show that the time evolution of the spectra depends on the body part, conserving solution and bee age. Further measurements are necessary to understand these effects and extend it to other social insects.

  15. Preparation of surface modified zinc oxide nanoparticle with high capacity dye removal ability

    SciTech Connect

    Mahmoodi, Niyaz Mohammad, E-mail: nm_mahmoodi@yahoo.com [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Najafi, Farhood [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)] [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)

    2012-07-15

    Highlights: ? Amine-functionalized zinc oxide nanoparticle (AFZON) was synthesized. ? Isotherm and kinetics data followed Langmuir isotherm and pseudo-second order kinetic model, respectively. ? Q{sub 0} of ZON for AB25, DR23 and DR31 was 20, 12 and 15 mg/g, respectively. ? Q{sub 0} of AFZON for AB25, DR23 and DR31 was 1250, 1000 and 1429 mg/g, respectively. ? AFZON was regenerated at pH 12. -- Abstract: In this paper, the surface modification of zinc oxide nanoparticle (ZON) by amine functionalization was studied to prepare high capacity adsorbent. Dye removal ability of amine-functionalized zinc oxide nanoparticle (AFZON) and zinc oxide nanoparticle (ZON) was also investigated. The physical characteristics of AFZON were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acid Blue 25 (AB25), Direct Red 23 (DR23) and Direct Red 31 (DR31) were used as model compounds. The effect of operational parameters such as dye concentration, adsorbent dosage, pH and salt on dye removal was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q{sub 0}) was 20 mg/g AB25, 12 mg/g DR23 and 15 mg/g DR31 for ZON and 1250 mg/g AB25, 1000 mg/g DR23 and 1429 mg/g DR31 for AFZON. It was found that dye adsorption followed Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% AB25, 86% for DR23 and 90% for DR31 were achieved in aqueous solution at pH 12. Based on the data of the present investigation, it can be concluded that the AFZON being an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions.

  16. Effect of CuO–Bi 2 O 3 on low temperature sintered MnZn-ferrite by sol–gel auto-combustion method

    Microsoft Academic Search

    Jun-Gang Hou; Yuan-Fang Qu; Wei-Bing Ma; Qing-Chi Sun

    2007-01-01

    A sol–gel auto-combustion method was investigated to incorporate small amounts of additives of Cu and Bi uniformly into soft\\u000a magnetic MnZn-ferrite nanoparticles, which were prepared by Fe(NO3)3·9H2O, Mn(NO3)2 and Zn(NO3)2·6H2O dissolved in water and citric acid. The powder was characterized by the X-ray diffraction analysis and transmission electron\\u000a microscope method. The effects of nano-particle sized powders in microstructure development and

  17. A General Strategy to Prepare TiO2-core Gold-shell Nanoparticles as SERS-tags

    PubMed Central

    Li, Wenbing; Guo, Yanyan; Zhang, Peng

    2009-01-01

    The synthesis and characterization of TiO2-based core-shell nanoparticles as surface-enhanced Raman Scattering (SERS) tags are reported. A hydrolysis approach is first used to generate colloidal TiO2 nanoparticles, which are subsequently tagged with Raman probe molecules and encapsulated within a gold nanoshell. The resulting core-shell nanoparticles are characterized by using a number of techniques including UV-visible spectroscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy (EDX) to confirm the successful coating of the Au shells. These core-shell nanoparticles exhibit very strong and reproducible SERS signals of the Raman probe molecules. Three different types of Raman probe molecules are used to prepare different SERS-active nanoparticles (SERS-tags), which demonstrates the versatility of the design. Such TiO2-based metal-coated core-shell nanoparticles will be useful as SERS-tags in biological assay and imaging applications. They may also provide a platform for fundamental studies in the ongoing investigations on the mechanisms of SERS. PMID:20473348

  18. In situ ultraviolet–visible absorbance measurement during and after solution plasma sputtering for preparation of colloidal gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Mizutani, Tsuyoshi; Murai, Takaaki; Nameki, Hirofumi; Yoshida, Tomoko; Yagi, Shinya

    2014-11-01

    The absorption spectra of the HCl, NaCl, and NaOH solutions during and after the solution plasma sputtering for the preparation of gold nanoparticles are measured by in situ ultraviolet–visible (UV–vis) spectroscopy to determine the particle diameter and behavior. In the solution plasma sputtering, gold particles are directly formed from the plasma phase and not by the reduction of Au3+ ions dissolved from electrodes. The initial diameter and behavior differ according to the solution used. In HCl solution, gold nanoparticles are formed and dissolve into Au3+ ions. When the solution is saturated, the gold nanoparticles grow by the aggregation of Au3+ ions. Cluster-sized particles are formed in NaCl solution that constitute nanoparticles, which are very stable for several days. Gold nanoparticles of 3 nm diameter are formed in NaOH solution, which aggregate over several days. The contribution of chlorine ions to the day-order stability of gold nanoparticles is suggested.

  19. Development of poly(anhydride) nanoparticles loaded with peanut proteins: the influence of preparation method on the immunogenic properties.

    PubMed

    Rebouças, Juliana De Souza; Irache, Juan Manuel; Camacho, Ana I; Esparza, Irene; Del Pozo, Victoria; Sanz, María L; Ferrer, Marta; Gamazo, Carlos

    2012-10-01

    Allergen-specific immunotherapy is based on the administration of allergens with the main disadvantage of inducing an allergic reaction. Within this context, we report the generation of an adjuvant and allergen-delivery system for peanut allergen immunotherapy with reduced IgE induction. Therefore, we prepared and characterized poly(anhydride) nanoparticles loaded with peanut proteins using the solvent displacement method, with some modifications in the manufacturing process. The precipitation of polymer was performed with either a mixture of ethanol and water or water. The resultant nanoparticles were dried by either freeze-drying or spray-drying, respectively. Poly(anhydride) nanoparticles loaded with peanut proteins were successfully developed, achieving both high encapsulation efficiency (70-80%) and manufacturing yield (60-80%). After intradermal immunization of mice (C57Bl/6) with peanut proteins incorporated into poly(anhydride) nanoparticles, a strong mixed T(H)1/T(H)2-type immune response was observed. Furthermore, we also provide, to our knowledge for the first time, clear evidence of the influence of formulation design on the immunostimulatory properties of nanoparticles. Taken together, our findings indicate that poly(anhydride) nanoparticles are efficient stimulators of immune responses and promising adjuvants and allergen-delivery systems applied for immunotherapy. PMID:22782031

  20. Fast preparation of printable highly conductive polymer nanocomposites by thermal decomposition of silver carboxylate and sintering of silver nanoparticles.

    PubMed

    Zhang, Rongwei; Lin, Wei; Moon, Kyoung-sik; Wong, C P

    2010-09-01

    We show the fast preparation of printable highly conductive polymer nanocomposites for future low-cost electronics. Highly conductive polymer nanocomposites, consisting of an epoxy resin, silver flakes, and incorporated silver nanoparticles, have been prepared by fast sintering between silver flakes and the incorporated silver nanoparticles. The fast sintering is attributed to: 1) the thermal decomposition of silver carboxylate-which is present on the surface of the incorporated silver flakes-to form in situ highly reactive silver nanoparticles; 2) the surface activation of the incorporated silver nanoparticles by the removal of surface residues. As a result, polymer nanocomposites prepared at 230 °C for 5 min, at 260 °C for 10 min, and using a typical lead-free solder reflow process show electrical resistivities of 8.1×10(-5), 6.0×10(-6), and 6.3×10(-5) ? cm, respectively. The correlation between the rheological properties of the adhesive paste and the noncontact printing process has been discussed. With the optimal rheological properties, the formulated highly viscous pastes (221 mPa s at 2500 s(-1)) can be non-contact-printed into dot arrays with a radius of 130 ?m. The noncontact printable polymer nanocomposites with superior electrical conductivity and fast processing are promising for the future of printed electronics. PMID:20735013