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1

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

2

Composition and magnetic properties of cobalt ferrite nano-particles prepared by the co-precipitation method  

Microsoft Academic Search

Cobalt ferrite nano-particles were prepared using the co-precipitation method followed by annealing treatment. The formation of nano-particles with different composition, microstructure and sizes were confirmed by X-ray diffraction, Raman, thermogravimetric-differential thermal analysis and transmission electron microscope. The magnetic hysteresis loops measured at room temperature revealed smaller effective magnetic anisotropy constant, coercivity and remanence ratio for the samples prepared by adding

Yue Zhang; Zhi Yang; Di Yin; Yong Liu; Chunlong Fei; Rui Xiong; Jing Shi; Gaolin Yan

2010-01-01

3

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

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

4

Magnetocaloric effect in ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

A comparative study of the magnetocaloric effect (MCE) is reported in two different types of chemically synthesized magnetic nanoparticle systems—cobalt ferrite and manganese zinc ferrite with mean size around 5 and 15 nm, respectively. While CoFe2O4 nanoparticles were synthesized using co-precipitation, the Mn0.68Zn0.25Fe2.07O4 (MZFO) nanoparticles were prepared by reverse micelle technique using AOT as surfactant. Our results indicate that the change in entropy with the change in applied magnetic field (dS/dH) is reasonably large for this class of nanoparticles and has a wide distribution over a broad temperature range covering the region above and below the blocking temperature. The maximum entropy change is influenced by the particle size, overall distribution in anisotropy and magnetic moments.

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

2006-12-01

5

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

Microsoft Academic Search

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

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

2007-01-01

6

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

Microsoft Academic Search

Sodium oleate was used as coating shell for magnetite, Zn ferrite and Co ferrite powders to stabilize them in the form of aqueous magnetic suspensions. The physical characterization was carried out by applying X-ray diffraction and magnetization measurements. Both crystallite size and magnetic core diameter ranged between 7 and 11 nm. The influence of magnetic nanoparticle suspensions (corresponding to magnetic

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

2010-01-01

7

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

Microsoft Academic Search

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–Fe2O3 ternary phase diagram. High-resolution electron micrographs of these crystallites show coherent intergrowth features involving hexaferrite and spinel ferrite structural blocks. Intergrown nickel ferrite

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

2004-01-01

8

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

Microsoft Academic Search

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-Fe2O3 ternary phase diagram. High-resolution electron micrographs of these crystallites show coherent intergrowth features involving hexaferrite and spinel ferrite structural blocks. Intergrown nickel ferrite

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

2004-01-01

9

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

Microsoft Academic Search

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

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

2011-01-01

10

4 °C preparation of ferrite nanoparticles having protein molecules immobilized on their surfaces  

NASA Astrophysics Data System (ADS)

Trypsin, a proteolytic enzyme or a protein, was immobilized onto the surfaces of ferrite (a Fe3O4-?Fe2O3 mixed solution) fine particles, ~8 nm in size, during the process in which the particles were synthesized from an aqueous solution. The process was performed in the open air at a temperature as low as 4 °C and on near-neutral condition of pH<=9, which is compatible with most of the bioactive molecules as well as trypsin. Therefore this technique is advantageous for preparing magnetite particles having biomolecules immobilized on their surfaces, which will be used for biomedical applications utilizing magnetic separation technique.

Nishimura, K.; Hasegawa, M.; Ogura, Y.; Nishi, T.; Kataoka, K.; Handa, H.; Abe, M.

2002-05-01

11

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

12

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

Microsoft Academic Search

Magnetic properties of ferrites are dependent on the crystalline structure and location of metal ions in the material. The most commonly used materials of nanoparticles in magnetic fluids are chemical stable spinel (2-3) ferrites. The preparation of ferrite nanoparticles for magnetic fluids synthesis needs a special technology. More commonly used is the wet chemical coprecipitation production technology of magnetic nanoparticles

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

2008-01-01

13

Low temperature chemical synthesis of ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

14

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

Microsoft Academic Search

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

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

15

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

NASA Astrophysics Data System (ADS)

Spherical uniform-sized iron ferrite nanoparticles were synthesized by adding a disaccharide and seed ferrite crystals into an aqueous reaction solution. The average size range 50-150 nm was controlled by choosing one out of five disaccharides and by changing the amount of the seed crystals. The particles had a saturation magnetization and a crystalline structure which are similar to those of intermediate Fe3O4-?-Fe2O3. When coated with citrate, the particles with nearly 100 nm diameter were stably suspended in water for 2 days. These novel particles will be utilized as magnetic carriers in biomedical applications.

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

2009-05-01

16

Synthesis and characterization of nickel ferrite magnetic nanoparticles  

Microsoft Academic Search

Nickel ferrite (NiFe2O4) nanoparticles are prepared by a polyvinyl alcohol (PVA) assisted sol–gel auto-combustion method. The structure, composition, morphology and magnetic properties of the gel precursor are characterized by powder XRD, FT-IR, TGA, HR-SEM, TEM, HR-TEM and VSM. XRD confirms the formation of single-phase nickel ferrite with space group of Fd3m and inverse spinel structure. The vibration properties of nanoparticles

P. Sivakumar; R. Ramesh; A. Ramanand; S. Ponnusamy; C. Muthamizhchelvan

2011-01-01

17

Preparation of single-crystal copper ferrite nanorods and nanodisks  

SciTech Connect

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

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

2005-06-15

18

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

Microsoft Academic Search

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

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

2009-01-01

19

Swift heavy ions irradiation studies on some ferrite nanoparticles  

Microsoft Academic Search

Ferrite nanoparticles of two different systems, namely Ni0.65Zn0.375In0.25Ti0.025Fe1.70O4 and Mn0.75Zn0.18Fe2.07O4, have been prepared by two different methods of ball milling (mechano synthesis) and coprecipitation (soft chemistry) respectively to investigate the effect of swift heavy ion irradiations on the structural, magnetic and ferromagnetic resonance parameters on these systems. The powder samples of Ni–Zn and Mn–Zn ferrites were irradiated with 190MeV Ag15+

B. Parvatheeswara Rao; K. H. Rao; P. S. V. Subba Rao; A. Mahesh Kumar; Y. L. N. Murthy; K. Asokan; V. V. Siva Kumar; Ravi Kumar; N. S. Gajbhiye; O. F. Caltun

2006-01-01

20

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

PubMed

We first succeeded in synthesizing ferrite nanoparticles containing Nd and B elements by a chemical route using a polyol process. The lattice constants of the ferrite nanoparticles were equivalent to 8.39Å of the lattice constant for Fe(3)O(4) with the spinel structure in a bulk state independently of the size in diameter and composition (Fe:Nd:B). The size in diameter was actually dominated by the amount of ligands (oleic acid and oleylamine) coating the nanoparticles and easily tuned by changing refluxing-time under reaction. The spinel-structured ferrite nanoparticles containing Nd and B elements showed large coercivity as compared to Fe(3)O(4) nanoparticles with the spinel structure, which were prepared by the same chemical method. By doping Nd and B elements into the spinel structure of ferrite, magnetic anisotropy increased in comparison with Fe(3)O(4) nanoparticles. According to the analysis of magnetization curve using the modified Langevin function, the ferrite nanoparticles displayed the coexistence of superparamagnetic and antiferromagnetic phases. The ferrite nanoparticles containing Nd and B elements exhibited magnetic core/shell structure on the basis of various magnetic properties. The interface effect between the superparamagnetic core and antiferromagnetic shell might enhance the effective magnetic anisotropy of the ferrite nanoparticles containing Nd and B elements. PMID:20167330

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

2010-02-01

21

Magnetocaloric effect (MCE) in Nickel Ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

22

Cation distribution dependence of magnetic properties of sol–gel prepared MnFe 2O 4 spinel ferrite nanoparticles  

Microsoft Academic Search

MnFe2O4 nanoparticles have been synthesized with a sol–gel method. Both differential thermal and thermo-gravimetric analyses indicate that MnFe2O4 nanoparticles form at 400°C. Samples treated at 450 and 500°C exhibit superparamagnetism at room temperature as implied from vibrating sample magnetometry. Mössbauer results indicate that as Mn2+ ions enter into the octahedral sites, Fe3+ ions transfer from octahedral to tetrahedral sites. When

Jianjun Li; Hongming Yuan; Guodong Li; Yanju Liu; Jinsong Leng

2010-01-01

23

Magnetic resonance of ferrite nanoparticles  

Microsoft Academic Search

Ferromagnetic resonance (FMR) experiments at 9.26GHz on non-interacting maghemite (?-Fe2O3) nanoparticles of ferrofluids are performed as a function of temperature (3.5–300K) and particle diameter (4.8–10nm). The orientational mobility of the particles inside the fluid is employed to monitor the orientational distribution of the anisotropy axes by solidifying the MF matrix under the external field. On those textured suspensions, angular analysis

F. Gazeau; J. C Bacri; F. Gendron; R. Perzynski; Yu. L Raikher; V. I. Stepanov; E. Dubois

1998-01-01

24

Cation distribution dependence of magnetic properties of sol-gel prepared MnFe2O4 spinel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

MnFe2O4 nanoparticles have been synthesized with a sol-gel method. Both differential thermal and thermo-gravimetric analyses indicate that MnFe2O4 nanoparticles form at 400 °C. Samples treated at 450 and 500 °C exhibit superparamagnetism at room temperature as implied from vibrating sample magnetometry. Mössbauer results indicate that as Mn2+ ions enter into the octahedral sites, Fe3+ ions transfer from octahedral to tetrahedral sites. When the calcination temperature increases from 450 to 700 °C, the occupation ratio of Fe3+ ions at the octahedral sites decreases from 43% to 39%. Susceptibility measurements versus magnetic field are reported for various temperatures (from 450 to 700 °C) and interpreted within the Stoner-Wohlfarth model.

Li, Jianjun; Yuan, Hongming; Li, Guodong; Liu, Yanju; Leng, Jinsong

2010-11-01

25

Low-temperature calorimetric properties of zinc ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

1995-10-01

26

Palladium nanoparticle supported on cobalt ferrite: an efficient magnetically separable catalyst for ligand free Suzuki coupling  

Microsoft Academic Search

Synthesis of Pd nanoparticle supported on cobalt ferrite magnetic nanoparticles has been achieved by direct addition of Pd nanoparticles during synthesis of cobalt ferrite nanoparticles by ultrasound assisted co-precipitation in absence of any surface stabilizers or capping agent. The catalytic performance of the Pd incorporated cobalt ferrite nanoparticles was examined in Suzuki coupling reaction in ethanol under ligand free condition.

Kula Kamal Senapati; Subhasish Roy; Chandan Borgohain; Prodeep Phukan

27

Formation and magnetic properties of Mn-Zn ferrites nanoparticles  

Microsoft Academic Search

The magnetic properties of ferrites are dependent on the crystalline structure and the location of metal ions in the material. The correct crystalline structure of a certain ferrite is formed by a special, very complex, technology. Bulk ferrites are synthesized at high temperatures (> 1300 K) under a special, very complex, thermal treatment. On the other hand, the preparation of

G. Kronkalns

2003-01-01

28

Preparation of ferrite single crystals by new floating zone technique  

Microsoft Academic Search

Single crystals of Ni ferrites and Ni-Zn ferrites having good uniformity were prepared by a new floating zone technique. In the preparation of the Ni-ferrite single crystal the initial molten zone was made from the material having a composition different from that of seed crystal. This made the composition of precipitate from molten zone the same as that of the

T. Akashi; K. Matumi; T. Okada; T. Mizutani

1969-01-01

29

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

Microsoft Academic Search

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

Shu Chang; Qiao Haoxue

2009-01-01

30

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

Microsoft Academic Search

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

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

2012-01-01

31

Magnetic properties of carbon stabilized multiferroic bismuth ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Carbon-stabilized bismuth ferrite (BiFeO3) nanoparticles have been synthesized by a self-combustion method, under ambient conditions and post annealing at selective temperatures between 400-800°C in air. BiFeO3 nanoparticles in carbon matrix show enhanced magnetic properties compared to its bulk counterpart.

Karan, T.; Ram, S.; Kotnala, R. K.

2012-06-01

32

Tailoring magnetic properties of Co-ferrite soft magnetic nanoparticles  

Microsoft Academic Search

Monodisperse Co-ferrite soft magnetic nanoparticles with particle size from 3 nm to 20 nm and different Co concentration have been synthesized by chemical solution methods. The composition was controlled by varying the mole ratios of the precursors in the solution. It has been found that magnetic properties of the nanoparticles can be tailored by changing the composition, particle size, as

N. Poudyal

2005-01-01

33

Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications.  

PubMed

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

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

2012-11-05

34

Dielectric properties of cobalt ferrite nanoparticles in ultrathin nanocomposite films.  

PubMed

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

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

2013-10-22

35

Temperature dependent coercivity and magnetization of nickel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Magnetic nanoparticles of nickel ferrite (size: 24±4 nm) have been synthesized by chemical coprecipitation method using stable ferric and nickel salts. Coercivity of nanoparticles has been found to increase with decrease in temperature of the samples. It has been observed that the coercivity follows a simple model of thermal activation of particle’s moment over the anisotropy barrier in the temperature range (10-300 K), in accordance with Kneller’s law for ferromagnetic materials. Saturation magnetization follows the modified Bloch’s law in the temperature range from 300 to 50 K. However, below 50 K, an abrupt increase in magnetization of nanoparticles was observed. This increase in magnetization at lower temperatures was explained with reference to the presence of freezed surface-spins and some paramagnetic impurities at the shell of nanoparticles that are activated at lower temperatures in core-shell nickel ferrite nanoparticles.

Maaz, K.; Mumtaz, A.; Hasanain, S. K.; Bertino, M. F.

2010-08-01

36

Preparation and Characteristics of Liquid Silicone Rubber Nanocomposite Containing Ultrafine Magnesium Ferrite Powder  

Microsoft Academic Search

Liquid silicone rubber with high thermal conductivity and effective electromagnetic interference (EMI) shielding properties was prepared. Silicone-based polymers were prepared by the equilibrium polymerization of cyclic siloxane and end-blockers. Magnesium ferrite nanoparticles having spinel magnetic properties were synthesized by the sol-gel method. A liquid silicone rubber (LSR) nanocomposite was prepared by compounding a,?-vinyl poly(dimethyl\\/methylpenylsiloxane) prepolymer (VPMPS), a, ?-hydrogen poly(dimethyl\\/hydrogenmethylsiloxane) prepolymer

Doo Whan Kang; Hak Gue Yeo; Kweon Soo Lee

2004-01-01

37

Preparation of high-permeability NiCuZn ferrite*  

PubMed Central

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

Hu, Jun; Yan, Mi

2005-01-01

38

Susceptibility of cobalt ferrite nanoparticles dispersed in polylactic acid microspheres  

NASA Astrophysics Data System (ADS)

In this study dynamic susceptibility (DS) was used to investigate cobalt ferrite (CoFe2O4) nanoparticles dispersed in polylactic-based microsized spheres. The peak position of the imaginary component of the DS curve was analyzed as a function of the polarizing external field, using a picture of an asymmetric double-well potential for the relaxation of the magnetization associated to the magnetic nanoparticle.

Silveira, L. B.; Santos, J. G.; Oliveira, A. C.; Tedesco, A. C.; Marchetti, J. M.; Lima, E. C. D.; Morais, P. C.

2004-05-01

39

Immobilization of biomolecules on biotinylated magnetic ferrite nanoparticles  

Microsoft Academic Search

We have developed biocompatible ferrite (Fe3O4) nanoparticles whose surfaces are functionalized with biotin molecule. The resulting magnetic nanoparticles with an average diameter of 8nm have a biotin-anchored morphology, which gives an exceptionally high affinity for the Cy3-labeled streptavidin. The spectroscopic and magnetic data results confirmed the presence of the interaction between biotin-anchored Fe3O4 particles and Cy3-labeled streptavidins. These biocompatible magnetic

Jungkweon Choi; Jong In Lee; Yong Bok Lee; Jung Hoon Hong; In Seon Kim; Yong Ki Park; Nam Hwi Hur

2006-01-01

40

Ni3Zn ferrite octahedral nanoparticles with high microwave permeability and high magnetic loss tangent  

NASA Astrophysics Data System (ADS)

Ni3Zn ferrite octahedral nanoparticles with grain size of about 40 nm were synthesized via a low temperature hydrothermal route. The saturation magnetization (Ms) and coercive force (Hc) of the sample are 57.5 emu/g and 197 Oe, respectively. In 50 MHz-8 GHz frequency range, the complex permeability and complex permittivity for Ni3Zn ferrite/wax composites containing 60 wt% ferrite powders were measured by a vector network analyzer. The real part ?r' of the permeability exhibits high values between 4 and 1.65 in 50 MHz-2 GHz range, and the imaginary part ?r'' of the permeability presents a broad peak with a maximum value of 1.53 at 2.1 GHz, the calculated reflection loss of ferrite/wax coating with the thickness of 8 mm reaches -13 dB at 2.1 GHz. The results indicate the as-prepared Ni3Zn ferrite octahedral nanoparticles can have applications in biomedicine, and microwave absorption and electric devices.

Wang, Zhongzhu; Wu, Mingzai; Jin, Shaowei; Li, Guang; Ma, Yongqing; Wang, Peihong

2013-10-01

41

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

42

Nanosized bismuth ferrite powder prepared through sonochemical and microemulsion techniques  

Microsoft Academic Search

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

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

2007-01-01

43

Thermal fluctuation and magnetization of Ni-Zn ferrite nanoparticles by particle size  

Microsoft Academic Search

Summary Ni1-xZnxFe2O4 (0?x?1) mixed ferrite nanoparticles encapsulated with amorphous-SiO2 were prepared by a wet chemical method. Particle sizes were controlled to range from 2.6 to 33.7 nm by heat treatment, and the particle size dependence of saturation magnetization Ms was investigated for the x=0.5 region. The Ms value decreased abruptly for particle sizes below about 6 nm. From the temperature

Y. Ichiyanagi; T. Uehashi; S. Yamada; Y. Kanazawa; T. Yamada

2005-01-01

44

Fabrication, characterization and magnetic behaviour of alumina-doped zinc ferrite nano-particles  

Microsoft Academic Search

Zinc ferrite nano-powders with a nominal composition of ZnFe2O4 were prepared by combustion synthesis using mixture of urea and ammonium nitrate as fuel. The influence of alumina-doping on the structural, morphological and magnetic properties of ZnFe2O4 nano-particles was investigated by means of X-ray powder diffraction (XRD), infrared (IR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM) and vibrating sample

N. M. Deraz

2011-01-01

45

Ionic magnetic fluid based on cobalt ferrite nanoparticles: Influence of hydrothermal treatment on the nanoparticle size  

NASA Astrophysics Data System (ADS)

Magnetic fluid based on cobalt ferrite nanoparticles was obtained using a hydrothermal treatment added to the Massart procedure. This treatment increases the average size of the nanoparticles from 11.9 to 18.7 nm and also improves the dispersity and crystallinity of the cobalt ferrite particles. The nanoparticles obtained after the hydrothermal treatment were dispersed in aqueous solvent by the classical procedure for ionic magnetic fluids. The ferrofluid thus obtained is stable at pH 7 and may be useful for hyperthermia applications.

Cabuil, Valérie; Dupuis, Vincent; Talbot, Delphine; Neveu, Sophie

2011-05-01

46

Magnetite-cobalt ferrite nanoparticles for kerosene-based magnetic fluids  

NASA Astrophysics Data System (ADS)

Due to the magnetic anisotropy introduced by the Co2+ ion in octahedral sites of cubic spinel ferrites, it is possible to tailor the magnetic properties by changing the cobalt content. Magnetic fluids with magnetite-cobalt ferrite nanoparticles given by the formula Co(x)Fe(3-x)O4 with x=0, 0.2 and 0.4 were prepared. Kerosene and oleic acid were used as liquid carrier and surfactant, respectively. Spherical magnetic nanoparticles were obtained by coprecipitation from metal salts and ammonium hydroxide; afterwards the magnetic fluids were obtained by a peptization process. Powder properties were characterized by X-ray diffraction (XRD), nitrogen adsorption desorption isotherma (BET), vibrating sample magnetometry (VSM) and fluids by transmission electron microscopy (TEM), thermogravimetric analyzer (TGA), VSM and the short-circuited transmission line technique.

Ayala-Valenzuela, O.; Matutes-Aquino, J.; Betancourt-Galindo, R.; García-Cerda, L. A.; Rodríguez Fernández, O.; Fannin, P. C.; Giannitsis, A. T.

2005-07-01

47

Dye removal using modified copper ferrite nanoparticle and RSM analysis.  

PubMed

In this paper, copper ferrite nanoparticle (CFN) was synthesized, modified by cetyl trimethylammonium bromide, and characterized. Dye removal ability of the surface modified copper ferrite nanoparticle (SMCFN) from single system was investigated. The physical characteristics of SMCFN were studied using Fourier transform infrared, scanning electron microscopy, and X-ray diffraction. Acid Blue 92, Direct Green 6, Direct Red 23, and Direct Red 80 were used as model compounds. The effect of operational parameters (surfactant concentration, adsorbent dosage, dye concentration, and pH) on dye removal was evaluated. Response surface methodology (RSM) was used for the analysis of the dye removal data. The experimental checking in these optimal conditions confirms good agreements with RSM results. The results showed that the SMCFN being a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions. PMID:23852534

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

2013-07-13

48

Magnetic micromachines prepared by ferrite plating technique  

NASA Astrophysics Data System (ADS)

By the sterolithography technique and the ferrite plating, we fabricated three types of magnetic micromachines which coated Fe3O4, Co0.39Fe2.61O4, and Co0.45Fe2.55O4, respectively. The stereolithography technique enables one to form the spiral-shape resinous templates and the ferrite plating enables one to coat the ferrites uniformly onto these templates from an aqueous solution. The total machine weight is light because a resin of the template body is almost the same density as water. We verified that the machines swim freely and wirelessly in water by applying a rotational magnetic field. As these machines coated with ferrites have the biocompatibility, there is the possibility of medical microrobots which swim in the human body for medical operations.

Nishimura, K.; Uchida, H.; Inoue, M.; Sendoh, M.; Ishiyama, K.; Arai, K. I.

2003-05-01

49

Size-dependent magnetic properties of calcium ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

The union of nanotechnology with the other fields of science heralds the influx of many newer and better technologies, with the capability to revolutionize the human life. In the present work, calcium ferrite nanoparticles were synthesized by conventional sol-gel method and were characterised by X-ray diffraction, Transmission electron microscope, Vibrating sample magnetometer and Fourier transform infrared spectroscope. The synthesized nanoparticles were calcined at different temperatures and their magnetic behaviour was studied. The synthesized nanoparticles calcined at 900 °C were formed in the shape of capsules and exhibited mixed characteristics of ferrimagnetic and paramagnetic grains with magnetic saturation of 0.85 emu/g whereas nanoparticles calcined at 500 °C were spherical in shape and exhibited superparamagnetic characteristics with saturation magnetization of 37.67 emu/g.

Khanna, Lavanya; Verma, N. K.

2013-06-01

50

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

51

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

52

Asymmetric hydrosilylation of ketones catalyzed by magnetically recoverable and reusable copper ferrite nanoparticles.  

PubMed

Herein we present magnetically recoverable and reusable copper ferrite nanoparticles for asymmetric hydrosilylation of several ketones. Up to 99% enantiometric excess was obtained at room temperature using polymethylhydrosiloxane as the stoichiometric reducing agent. The copper ferrite nanoparticles were magnetically separated, and the efficiency of the catalyst remains almost unaltered up to three cycles. PMID:19518151

Kantam, M Lakshmi; Yadav, Jagjit; Laha, Soumi; Srinivas, Pottabathula; Sreedhar, Bojja; Figueras, F

2009-06-19

53

Preparation of TEM samples of ferritic alloys.  

SciTech Connect

We describe techniques for electropolishing irradiated ferritic specimens for examination under the TEM in situations where the foil quality is of utmost importance. First, we describe some modifications to the standard technique for making plan-view specimens aimed at optimizing the foil quality. Second, we describe a technique for making plan-view specimens from a region of buried damage in a specimen irradiated with 2 MeV Fe{sup +} ions.

Yao, Z.; Xu, S.; Jenkins, M. L.; Kirk, M. A.; Materials Science Division; Univ. of Oxford

2008-01-01

54

Conjugation of manganese ferrite nanoparticles to an anti Sticholysin monoclonal antibody and conjugate applications  

Microsoft Academic Search

In this study the potential applications of manganese ferrite (MnFe2O4) nanoparticles for bioanalytical applications are evaluated. These magnetic nanoparticles show peroxidase-like activity similar to that reported for magnetite nanoparticles and peroxidase enzyme. Based on this finding, colloidal suspensions of manganese ferrite were conjugated to an anti-Sticholysin II (StII) monoclonal antibody. The resulting conjugate was then used as a revealing tool

V. Figueroa-Espí; A. Alvarez-Paneque; M. Torrens; A. J. Otero-González; E. Reguera

2011-01-01

55

Mössbauer studies of superparamagnetic ferrite nanoparticles for functional application  

NASA Astrophysics Data System (ADS)

Nanoparticles of CoFe2O4 and MnFe2O4 prepared for functional applications in nanomedicine were studied using Mössbauer spectrometry. Superparamagnetic properties of nanoparticles of different size and composition were compared applying collective excitations and multilevel models for the description of the Mössbauer spectra.

Mažeika, K.; Jagminas, A.; Kurtinaitien?, M.

2013-04-01

56

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

PubMed

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. PMID:23164999

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

2012-11-19

57

Influence of cobalt on structural and magnetic properties of nickel ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Improving the magnetic response of nanocrystalline nickel ferrites is the key issue in high density recording media. A series of cobalt substituted nickel ferrite nanoparticles with composition Ni(1?x)CoxFe2O4, where 0.0 ? x ? 1.0, are synthesized using co-precipitation method. The XRD spectra revealed the single phase spinel structure and the average sizes of nanoparticles are estimated to be 16–19 nm. These sizes are small enough to achieve the suitable signal to noise ratio in the high density recording media. The lattice parameter and coercivity shows monotonic increment with the increase of Co contents ascribed to the larger ionic radii of the cobalt ion. The specific saturation magnetization (Ms), remanent magnetization (Mr) and the coercivity (Hc) of the spinel ferrites are further improved by the substitutions of Co+2 ions. The values of Ms for NiFe2O4 and CoFe2O4 are found to be 43.92 and 78.59 emu/g, respectively and Hc are in the range of 51–778 Oe. The FTIR spectra of the spinel phase calcinated at 600 °C exhibit two prominent fundamental absorption bands in the range of 350–600 cm?1 assigned to the intrinsic stretching vibrations of the metal at the tetrahedral and octahedral sites. The role played by the Co ions in improving the structural and magnetic properties are analyzed and understood. Our simple, economic and environmental friendly preparation method may contribute towards the controlled growth of high quality ferrite nanopowders, potential candidates for recording.

Ati, Ali A.; Othaman, Zulkafli; Samavati, Alireza

2013-11-01

58

Ultrafine, perfectly spherical Ni–Zn ferrite nanoparticles, with ultranarrow distribution, isolated in a silica matrix, prepared by a novel synthesis method in the liquid phase  

Microsoft Academic Search

Nanocomposites of the type (Ni–Zn)Fe2O4\\/SiO2 have been synthesized using a novel chemical route involving the liquid phase. Metallic nitrates (MN)–ethylene glycol (EG)–silica gels were prepared as a result of the polycondensation reaction, using as precursors MN of Fe, Ni, Zn and tetraethylorthosilicate, to which EG was added. After gelling and drying, the sols were first subjected to a thermal treatment

M. Stefanescu; C. Caizer; M. Stoia; O. Stefanescu

2006-01-01

59

Synthesis and characterization of silica coated potassium ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Silica coated potassium ferrite nanoparticles (KFeO2 NPs) have been synthesized by conventional stöber process. The orthorhombic structure of KFeO2 NPs has been retained even after silica coating, only a slight variation has been observed in the angle range of 20°-25° (occurring due to amorphous silica), as shown by the X-ray diffraction pattern. The crystallite size using Scherrer's formula of bare and silica coated KFeO2 NPs has been calculated to be 21.0 nm and 22.5 nm, respectively. The spherical formation of silica coated KFeO2 NPs has been revealed by transmission electron microscope. Presence of silica on KFeO2 NPs has been confirmed by energy dispersive X-ray spectroscope. A small magnetic saturation value of 3.67emu/g has been observed in the vibrating sample magnetometer analysis.

Khanna, Lavanya; Verma, N. K.

2013-06-01

60

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

Microsoft Academic Search

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

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

2010-01-01

61

Magnetic properties of cobalt-ferrite nanoparticles embedded in polystyrene resin  

NASA Astrophysics Data System (ADS)

Samples of maghemite and cobalt-ferrite nanoparticles (sizes, 3-10 nm) were prepared by cross-linking sulfonated polystyrene resin with aqueous solutions of (1) FeCl2, (2) 80%FeCl2+20%CoCl2, (3) FeCl3, and (4) 80%FeCl3+20%CoCl2 by volume. Chemical analysis, x-ray powder-diffraction, and 57Fe Mössbauer spectroscopic measurements show that samples 1 and 3 consist of ?-Fe2O3 nanoparticles (sizes, ~10 and 3 nm) and sample 2 and 4 consist of CoxFe3-xO4 nanoparticles (sizes, ~10 and 4 nm). The temperature dependence of the zero-field-cooled and field-cooled magnetizations at low temperatures, together with a magnetic hysteresis in the M versus H data below blocking temperatures, demonstrate superparamagnetic behavior. The introduction of Co in the iron oxide-resin matrix results in an increase in the blocking temperature of nanoparticles.

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

2006-04-01

62

The alignment of barium ferrite nanoparticles from their suspensions in electric and magnetic fields.  

PubMed

The alignment of plate-like barium ferrite nanoparticles, with diameters of 10-350 nm and thicknesses of 3-10 nm, in electric and/or magnetic fields was studied. Stable suspensions were prepared in 1-butanol with dodecylbenzenesulphonic acid as a surfactant. The deposits were produced from the suspensions with classic electrophoretic deposition, electrophoretic deposition in a magnetic field, and with drying in a magnetic field. The experiments, supported by theoretical calculations, show that the alignment of the nanoplates in the deposits was determined by the interplay between the hydrodynamic, electric, and magnetic forces. The preferential alignment of the nanoplates in plane with the substrate coincided with their magnetic orientation, and it increased with the shape anisotropy of the particles. The deposits were sintered at 1150 °C for 5 h to obtain ceramic films, which showed a magnetic orientation up to 90%. PMID:22834411

Lisjak, Darja; Ovtar, Simona

2012-08-07

63

Size and crystallinity-dependent magnetic properties of copper ferrite nano-particles  

Microsoft Academic Search

Copper ferrite nano-crystals were synthesized by a combustion route depending upon the glycine–nitrate process and also by ceramic method. In order to investigate the effect of degree of crystallinity and crystallite size of copper ferrite system on its magnetic properties, a series of Cu-ferrite samples with different degrees of crystallinity and crystallite size were produced by varying the preparation temperatures

N. M. Deraz

2010-01-01

64

Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

65

Low temperature polymer assisted hydrothermal synthesis of bismuth ferrite nanoparticles  

Microsoft Academic Search

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

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

2008-01-01

66

Preparation and antibacterial activity of chitosan nanoparticles  

Microsoft Academic Search

Chitosan nanoparticles, such as those prepared in this study, may exhibit potential antibacterial activity as their unique character. The purpose of this study was to evaluate the in vitro antibacterial activity of chitosan nanoparticles and copper-loaded nanoparticles against various microorganisms. Chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Copper ions were adsorbed onto the

Lifeng Qi; Zirong Xu; Xia Jiang; Caihong Hu; Xiangfei Zou

2004-01-01

67

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

Microsoft Academic Search

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

Ali Ghasemi; Vladimir Sepelak; Xiaoxi Liu; Akimitsu Morisako

2009-01-01

68

Spin-flop transition, magnetic and microwave absorption properties of ?-Fe2O4 spinel type ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

We have prepared NiFe2O4, CoFe2O4, Ni0.6Zn0.4Fe2O4 and ZnFe2O4 spinel type ferrite nanoparticles by surfactant-assisted hydrothermal process using cetyltrimethylammonium bromide (CTAB). The spin-flop transition, magnetic, dielectric and permittivity characterizations have been investigated. The spin-flop transition occurs from antiferromagnetic state to mixed state and then ferromagnetic state for Zn doped samples. The spin-flop transition occurs in the temperature range of 50-250 K. The ionic conduction, dipolar relaxation, atomic polarization and electronic polarization are the main mechanisms that contribute to the permittivity of a dielectric material. The permittivity increases with increasing frequency. This suggests a resonance behavior, which is expected when the ferrite samples are highly conductive and skin effect become significant. These samples will provide great benefits for electromagnetic applications and electromagnetic interference shielding characteristics.

Yalç?n, Orhan; Bayrakdar, Harun; Özüm, Songül

2013-10-01

69

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

NASA Astrophysics Data System (ADS)

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

Lal, Madan; Singh, M.

2007-01-01

70

Synthesis of cobalt ferrite nano-particles and their magnetic characterization  

Microsoft Academic Search

Cobalt ferrite nano-particles (CoFe2O4) were synthesized by the co-precipitation method with ammonium hydroxide as an alkaline solution. The reactions were carried out at different temperatures between 20 and 80°C. The nano-particles have been investigated by magnetic measurements, X-ray powder diffraction and transmission electron microscopy. The average crystallite size of the synthesized samples was between 11 and 45nm, which was found

M. M. El-Okr; M. A. Salem; M. S. Salim; R. M. El-Okr; M. Ashoush; H. M. Talaat

2011-01-01

71

Microwave absorbing properties of structural nanocomposites with surface treated Co ferrite nanoparticles as filler  

NASA Astrophysics Data System (ADS)

An analysis of the microwave absorbing properties of several polymer-(epoxy) based nanocomposites is presented. The nanoparticles of interest for this study were cobalt ferrite nanoparticles. For better dispersion of the nanoparticles in the polymer matrix surface treatment of the nanoparticles with silane compounds was performed. The nanoparticles were surface-treated with 3-glycidoxypropyl- (GPTMS), aminopropyl- (APTMS) or methyl-silsesquioxane (MTMS). The nanoparticles with GPTMS-coating dispersed well in epoxy without sedimentation while the other nanoparticles formed agglomerates in epoxy. The GPTMS-based composites showed higher fracture toughness than the MTMS-based composites. The microwave properties, permittivity and permeability, of GPTMS-based composites were measured in the frequency range between 3.95 GHz and 18 GHz and showed no influence of surface treatment on permeability.

Jänis, A.; Olsson, R. T.; Savage, S. J.; Klement, U.

2010-03-01

72

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

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

73

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

PubMed

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

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

2012-03-30

74

SAXS study of hexagonal W-type barium ferrite nanoparticles  

Microsoft Academic Search

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

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

75

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

Microsoft Academic Search

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

Jianxun Qiu; Le Liang; Mingyuan Gu

2005-01-01

76

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

PubMed

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

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

2013-05-14

77

The concentration dependence of relaxation times of hydrogen proton in the aqueous solution of iron ferrite magnetic nanoparticles  

Microsoft Academic Search

By the direct coprecipitation of the aqueous solution of iron salt and tetramethylammonium hydroxide solution the stable iron ferrite nanoparticles were formulated. These nanoparticles were found to have uniform sizes of about 7nm, and also showed no coalescence in the aqueous solution for a few months. The superparamagnetic behavior of these nanoparticles was checked by a vibrating sample magnetometer. Also,

Ilsu Rhee; Chan Kim

2003-01-01

78

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

PubMed

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

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

2013-09-12

79

Ferrites  

Microsoft Academic Search

With d.c. electrical resistivities several orders of magnitude greater than those of the ferromagnetic metals, and magnetic saturation intensities in some cases less than one order of magnitude smaller, the ferrites gave promise of greater `effective permeability' and lower `eddy-current' loss in high-frequency magnetic fields. Attempts to realize these advantages have had limited success, but have led to a deeper

A. Fairweather; F. F. Roberts; A. J. E. Welch

1952-01-01

80

Magnetic properties of Co1-xNix/2Srx/2Fe2O4 (x = 0-1) ferrite nanoparticles synthesized by self-assembling media of reverse micelles  

NASA Astrophysics Data System (ADS)

Co1-xNix/2Srx/2Fe2O ferrite nanoparticles were prepared using reverse micelle process. Mean particle size of pure ferrite nanoparticles is approximately 9 nm as determined by transmission electron microscopy (TEM). The heating thermograms of samples confirmed that there are no hydroxides in the ferrites fabricated via reverse micelles. Vibrating sample magnetometer (VSM) was employed to probe magnetic properties of nanosized. It was found that with increasing the amount of Ni and Sr in nanosized ferrites, the saturation magnetization decreases. Magnetic dynamics of the samples was studied by the measurement of AC magnetic susceptibility versus temperature at different frequencies. The phenomenological Néel - Brown and Vogel - Fulcher models were employed to distinguish between interacting or non-interacting system. Results show that there is strong interaction between fine particles.

Ghasemi, A.; Kaewrawang, A.; Liu, X.; Morisako, A.

2011-07-01

81

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

PubMed

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

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

2009-02-01

82

Magnetic properties of bio-synthesized zinc ferrite nanoparticles  

SciTech Connect

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

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

2011-01-01

83

Relaxivities of hydrogen protons in aqueous solutions of gold-coated manganese ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Manganese ferrite nanoparticles were synthesized using the reverse micelle method and were coated with gold. TEM (transmission electron microscope) pictures showed that the shapes of the synthesized nanoparticles were almost spherical with an average diameter of 12 nm and a standard error of 4 nm. The bonding status of gold on the nanoparticle surfaces was checked using a Fourier transform infrared spectrometer (FTIR). The T1 and the T2 relaxation times of the hydrogen protons in aqueous solutions of the coated manganese-ferrite nanoparticles were determined using magnetic resonance imaging (MRI). The 1/ T 1 and the 1/ T 2 versus concentration curves for the nanoparticles showed a linear dependence. The T1 and the T2 relaxivities were found to be r 1 = 6.01 ± 0.12 and r 2 = 83.3 ± 0.55 mM-1 s -1. The ratio of r 2/ r 1 was 13.9; this is larger than the ratios of r 2/ r 1 for commercial T2 MRI contrast agents, indicating that the nanoparticles studied herein can serve as a T2 contrast agent with high efficacy.

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

2013-06-01

84

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

SciTech Connect

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

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

2010-12-01

85

Manifestation of weak ferromagnetism and photocatalytic activity in bismuth ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Bismuth ferrite (BFO) nanoparticles were synthesized by auto-ignition technique with and without adding ignition fuel such as citric acid. The presence of citric acid in the reaction mixture yielded highly-magnetic BFO/?-Fe2O3 nanocomposite. When this composite was annealed to 650°C, a single phase BFO was formed with average crystallite size of 50 nm and showed weak ferromagnetic behavior. Conversely, the phase pure BFO prepared without adding citric acid exhibited antiferromagnetism because of its larger crystallite size of around 70 nm. The visible-light driven photocatalytic activity of both the pure BFO and BFO/?-Fe2O3 nanocomposite were examined by degrading methyl orange dye. The pure BFO showed a moderate photocatalytic activity; while BFO/?-Fe2O3 nanocomposite showed enhanced activity. This could be probably due to the optimal band gap ratio between BFO and ?-Fe2O3 phases reduced the recombination of electron-hole pairs which aided in the enhancement of photocatalytic activity.

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

2013-02-01

86

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

Microsoft Academic Search

Nanocrystalline (NC) ferrite powders have been synthesized using a 50 kW-3 MHz rf thermal plasma torch for high-frequency soft magnet applications. A mixed powder of Ni and Fe (Ni:Fe=1:2), a NiFe permalloy powder with additional Fe powder (Ni:Fe=1:2), and a NiFe permalloy powder (Ni:Fe=1:1) were used as precursors for synthesis. Airflow into the reactor chamber was the source of oxygen

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

2002-01-01

87

Two-variables scaling of the magnetic viscosity in Ba-ferrite nano-particles  

Microsoft Academic Search

Careful measurements of the magnetic viscosity S = dM\\/ d ln t of non-oriented nano-particles of Ba-ferrite (317 Å as mean diameter) show a remarkable scaling plot vs. two variables: the usual T ln(t\\/tau0 and the applied magnetic field H. This plot takes into account two distributions, the particle size rho(s) and the switching field v(H0) distributions. This last plays

B. Barbara; L. C. Sampaio; A. Marchand; O. Kubo; H. Takeuchi

1994-01-01

88

Mössbauer studies of La Zn substitution effect in strontium ferrite nanoparticles  

Microsoft Academic Search

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

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

2005-01-01

89

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

Microsoft Academic Search

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

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

2005-01-01

90

Morphology of cobalt ferrite nanoparticle-polyelectrolyte multilayered nanocomposites  

NASA Astrophysics Data System (ADS)

Novel magnetic nanocomposite films with controlled morphology were produced via the electrostatic layer-by-layer assembly of cationic CoFe2O4 nanoparticles and anionic poly(3,4-ethylenedioxy thiophene)/poly(styrene sulfonic acid) (PEDOT:PSS) complex. The electrostatic interaction between nanoparticle and the polyelectrolyte complex ensured a stepwise growth of the nanocomposite film with virtually identical amounts of materials being adsorbed at each deposition cycle as observed by UV-vis spectroscopy. AFM images acquired under the tapping mode revealed a globular morphology with dense and continuous layers of nanoparticles with voids being filled with polymeric material.

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

2011-05-01

91

Preparation of DPPE-Stabilized Gold Nanoparticles  

ERIC Educational Resources Information Center

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

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

2005-01-01

92

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

Microsoft Academic Search

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

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

2005-01-01

93

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

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

94

Preparation of Nickel Thin Sheets with Nanosized Ferrites by Combustion Synthesis and Electroforming  

NASA Astrophysics Data System (ADS)

Composite nickel sheets with nanosized nickel--zinc ferrite particles were prepared as electromagnetic shielding materials by electroforming in a modified nickel--sulfate bath with nickel--zinc ferrite particles. The nanosized nickel--zinc ferrites were prepared by combustion synthesis and mechanical milling. The combustion temperature and propagation rate were about 1150 °C and 8.9 mm/s, respectively. Neutron diffractometry revealed that the final nickel--zinc ferrites formed by combustion synthesis followed by mechanical milling were Ni0.42Zn0.58Fe2O4 with the crystal structure and lattice parameter of Fd3m and 0.84124 nm, respectively. Microstructure observation and chemical analysis by transmission electron microscopy and energy-dispersive spectroscopy respectively showed that nanosized nickel--zinc ferrite particles with a diameter of about 20 nm exist in the thin composite nickel sheet. Maximum magnetization (Ms), residual magnetization (Mr), and coercive force (i) were 7.75 Wb/m2/kg, 0.88 m3/kg, and 1297 A/m, respectively. The complex permeability decreases with an increase in frequency, and its real value (?\\text{r{}') has an maximum at about 0.65 GHz.

Choi, Yong

2011-01-01

95

Correlation of spin and structure in doped bismuth ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

96

Preparation and properties of tetragonal bismuth ferrite lead titanate thin films using pulsed laser deposition  

Microsoft Academic Search

Thin films of tetragonal bismuth ferrite lead titanate compositions have been prepared by pulsed laser deposition (PLD). The films exhibit a dense columnar grain growth which is characteristic of PLD. XRD analysis reveals that the films have a preferred (111) texture. The dielectric properties and polarisation-field hysteresis behaviour of the films is also reported.

M. A. Khan; T. P. Comyn; A. J. Bell

2007-01-01

97

Synthesis of Ni–Zn ferrite nanoparticles in radiofrequency thermal plasma reactor and their use for purification of histidine-tagged proteins  

Microsoft Academic Search

Superparamagnetic Ni–Zn ferrite nanoparticles were synthesized in radiofrequency thermal plasma reactor from aqueous solutions\\u000a of Ni- and Zn-nitrates. The nanoparticles were studied for protein purification performance in both quantitative and qualitative\\u000a terms. For comparison, experiments were also performed by Ni-charged affinity chromatography. It was proved that the Ni–Zn\\u000a ferrite nanoparticles effectively purified histidine-tagged proteins with a maximum protein binding capacity

Tivadar Feczkó; Adél Muskotál; Loránd Gál; János Szépvölgyi; Anett Sebestyén; Ferenc Vonderviszt

2008-01-01

98

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

99

Synthesis and optical properties of nickel zinc ferrite nanoparticles grown within mesoporous silica template  

NASA Astrophysics Data System (ADS)

Nanocomposite (NC) of nickel zinc ferrite (NZF) in mesoporous silica template (KIT-6) was synthesized and characterized in this work. Impregnation procedure was used to synthesize NZF nanoparticles within the pores of KIT-6. The samples were characterized by transmission electron microscopy (TEM), FTIR and UV-Vis absorption studies and room temperature (RT) photoluminescence (PL) measurement. The morphology from Transmission Electron Microscopy of the NC showed the ordered porous structure of KIT-6 remained undistorted even after the incorporation of NZF nanoparticles within its pores. From UV-Vis spectra of the NC, a blue shift in the absorption band due to quantum confinement effect was found. Due to some defects present a broad PL peak centred at 490 nm after excitation at 428 nm of the NC was observed.

Banerjee, Shilpi; Chakravorty, Dipankar

2012-06-01

100

Preparing nanoparticle assemblies with number density gradients  

Microsoft Academic Search

We report on preparing assemblies of gold nanoparticles with gradient in number densities on flat silica-covered substrates. The methodology consists of : i) first forming a molecular gradient of amino groups (-NH2) on the substrate by vapor deposition of amine-terminated silane molecules, followed by ii) attachment of gold nanoparticles to -NH2 functional groups by immersing the substrate in a colloidal

Rajendra Bhat; Daniel Fischer; Jan Genzer

2002-01-01

101

Structural and magnetic properties of cadmium substituted manganese ferrites prepared by hydrothermal route  

NASA Astrophysics Data System (ADS)

Cd-substituted manganese ferrite Mn1-xCdxFe2O4 powders with x having values 0.0, 0.1, 0.3 and 0.5 have been synthesized by hydrothermal route at 180 °C in presence of NaOH as mineralizer. The obtained ferrite samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The XRD analysis showed that pure single phases of cubic ferrites were obtained with x upto 0.3. However, sample with x?0.5 showed hexagonal phase of cadmium hydroxide (Cd(OH)2) besides the ferrite phase. The increase in Cd-substitution upto x=0.3 leads to an increase in the lattice parameter as well as the average crystallite size of the prepared ferrites. The average crystallite size increased by increasing the Cd-content and was in the range of 39-57 nm. According to VSM results, the saturation magnetization increased with Cd ion substitution.

Mostafa, Nasser Y.; Zaki, Z. I.; Heiba, Z. K.

2013-03-01

102

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

PubMed

Magnetic nanoparticles (NPs) are of increasing interest in various industrially relevant products. For these, the development of greener and faster approaches facilitating scaling-up production is of paramount importance. Here, we report a novel, green and potentially scalable approach for the continuous and ultrafast (90 s) synthesis of superparamagnetic ferrite NPs (MnFe(2)O(4), Fe(3)O(4)) in supercritical ethanol (scEtOH) at a fairly moderate temperature (260 °C). ScEtOH exhibits numerous advantages such as its production from bio-resources, its lack of toxicity and its relatively low supercritical coordinates (p(c) = 6.39 MPa and T(c) = 243 °C), being therefore appropriate for the development of sustainable technologies. The present study is completed by the investigation of both in situ and ex situ NP surface functionalization. The as-obtained nanoparticles present good crystallinity, sizes below 8 nm, superparamagnetic behavior at room temperature and high saturation magnetization. Moreover, depending on the capping strategy, the ferrite NPs present extended (for in situ coated NPs) or short-term (for ex situ coated NPs) colloidal stability. PMID:23386040

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

2013-02-05

103

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

PubMed Central

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

2011-01-01

104

Magnetic properties of Co-ferrite-doped hydroxyapatite nanoparticles having a core/shell structure  

NASA Astrophysics Data System (ADS)

The magnetic properties of Co-ferrite-doped hydroxyapatite (HAP) nanoparticles of composition Ca10-3xFe2xCox(PO4)6(OH)2 (where x=0, 0.1, 0.2, 0.3, 0.4 and 0.5% mole) are studied. Transmission electron microscope micrograms show that the 90 nm size nanoparticles annealed at 1250 °C have a core/shell structure. Their electron diffraction patterns show that the shell is composed of the hydroxyapatite and the core is composed of the Co-ferrite, CoFe2O4. Electron spin resonance measurements indicate that the Co2+ ions are being substituted into the Ca(1) sites in HAP lattice. X-ray diffraction studies show the formation of impurity phases as higher amounts of the Fe3+/Co2+ ions which are substituted into the HAP host matrix. The presence of two sextets (one for the A-site Fe3+ and the other for the B-site Fe3+) in the Mössbauer spectrum for all the doped samples clearly indicates that the CoFe2O4.cores are in the ferromagnetic state. Evidence of the impurity phases is seen in the appearance of doublet patterns in the Mössbauer spectrums for the heavier-doped (x=0.4 and 0.5) specimens. The decrease in the saturation magnetizations and other magnetic properties of the nanoparticles at the higher doping levels is consistent with some of the Fe3+ and Co2+ which being used to form the CoO and Fe2O3 impurity phase seen in the XRD patterns.

Petchsang, N.; Pon-On, W.; Hodak, J. H.; Tang, I. M.

2009-07-01

105

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

106

Multiporous ceria nanoparticles prepared by spray pyrolysis  

Microsoft Academic Search

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

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

2010-01-01

107

Enhanced visible-light-response photocatalytic activity of bismuth ferrite nanoparticles  

Microsoft Academic Search

Multiferroic BiFeO3 nanoparticles were prepared by a sol–gel rapid calcination technique with average diameter of 35nm with narrow size distribution. The band gap was determined to be 2.06eV, indicating their potential application as visible-light-response photocatalyst. The photocatalytic behaviors of BiFeO3 nanoparticles were estimated by the degradation of Rhodamine B (RhB) under visible light irradiation. And the photocatalytic activities under different

Xiong Wang; Ying Lin; Xifeng Ding; Jinguo Jiang

2011-01-01

108

Preparing nanoparticle assemblies with number density gradients  

NASA Astrophysics Data System (ADS)

We report on preparing assemblies of gold nanoparticles with gradient in number densities on flat silica-covered substrates. The methodology consists of : i) first forming a molecular gradient of amino groups (-NH2) on the substrate by vapor deposition of amine-terminated silane molecules, followed by ii) attachment of gold nanoparticles to -NH2 functional groups by immersing the substrate in a colloidal gold solution. Experiments using atomic force microscopy (AFM) reveal that the number density of nanoparticles on the substrate varies gradually as a function of the position on the substrate. Near edge x-ray absorption fine structure (NEXAFS) studies confirm that the decrease of the nanoparticle density is associated with the decrease of the number of the -NH2 groups anchored to the substrate. We demonstrate that the number density and spatial distribution of the nanoparticles within the gradients can be tuned by contolling the vapor diffusion of silane molecules. In addition we show that this simple methodology can be further extended to create "double gradients" of nanoparticles.

Bhat, Rajendra; Fischer, Daniel; Genzer, Jan

2002-03-01

109

Gas sensing properties of magnesium ferrite prepared by co-precipitation method  

Microsoft Academic Search

Polycrystalline magnesium ferrite (MgFe2O4) was prepared by the co-precipitation method. The synthesized compound was characterized for their phase and morphology by X-ray diffraction and scanning electron microscopy, respectively. Conductance responses of the (MgFe2O4) were measured towards gases like hydrogen sulfide (H2S), liquefied petroleum gas (LPG), ethanol vapors (C2H5OH), SOx, H2, NOx, NH3, methanol, acetone and petrol. The gas sensing characterstics

P. P. Hankare; S. D. Jadhav; U. B. Sankpal; R. P. Patil; R. Sasikala; I. S. Mulla

2009-01-01

110

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

PubMed

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

Soltani, T; Entezari, M H

2013-02-07

111

Giant antiresonance in electromagnetic wave reflection from a 3D structure with ferrite spinel nanoparticles  

NASA Astrophysics Data System (ADS)

We analyze the microwave properties of nanocomposite materials obtained by embedding opal matrices (regular packing of SiO2 spheres about 250 nm in diameter) of ferrite spinel nanoparticles in the interspherical space. It is found that the main reason for microwave changes is the magnetic resonance in a nanocomposite. In addition to the resonance, antiresonance also takes place, which is manifested as a minimum of absorbed power at frequencies higher than a certain frequency characteristic of the given type of ferrite particles. Antiresonance appears in the fields smaller than the resonance field. The amplitude of the reflected signal in antiresonance increases fourfold. The measurements are taken in the frequency range from 26 to 38 GHz. The change in the moduli of transmission and reflection coefficients in the external magnetic field in a rectangular waveguide containing a nanocomposite is analyzed. The modulus of the wave transmittance through a rectangular resonator with a nanocomposite specimen is measured. The structural analysis of nanocomposites is carried out. In addition, the magnetization curves and hysteresis loops are measured.

Ustinov, V. V.; Rinkevich, A. B.; Perov, D. V.; Burkhanov, A. M.; Samoylovich, M. I.; Kleshcheva, S. M.; Kuznetsov, E. A.

2013-04-01

112

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

113

Wet chemical synthesis and gas sensing properties of magnesium zinc ferrite nano-particles  

Microsoft Academic Search

In the present work we have synthesized, magnesium ferrite, zinc ferrite, and magnesium zinc ferrite solid solutions using an economic wet chemical synthesis route. To understand the phase formation behavior of the synthesized powders, infra-red spectroscopy in conjunction with X-ray Rietveld refinement analyses has been performed. The structural characteristics of these ferrite powders are correlated with their room temperature magnetic

D. C. Bharti; K. Mukherjee; S. B. Majumder

2010-01-01

114

Aqueous synthesis and transmission electron microscopy observation of seed-grown spherical ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

Uniform-sized spherical iron ferrite nanoparticles grew on seed crystals in an aqueous solution containing sucrose. Using the seed crystals which were highly dispersed in acidic or alkaline seed-crystal suspension without relation to pH of the suspension, we widely controlled the particle diameter in the range 20-200 nm by changing the additive amount of the seed crystals. By transmission electron microscopy observation and X-ray diffraction analysis, it indicated that the particles were highly crystalline but not amorphous. Selected area diffraction patterns of the particles by using transmission electron microscope revealed that the particles were composed of one to several crystals. Thus we provided the evidence that the particles grew on clusters composed of one to several seed crystals to which those of several dozen seed crystals were disintegrated.

Tanaka, T.; Tada, M.; Nakagawa, T.; Abe, M.

2012-03-01

115

Variation of structural and hyperfine parameters in nanoparticles of Cr-substituted Co-Zn ferrites  

NASA Astrophysics Data System (ADS)

The effect of Cr substitution into nanocrystalline Co-Zn ferrite prepared by the chemical coprecipitation method has been studied. Mössbauer studies at a temperature (20K) well below the blocking temperatures of the samples show that Cr goes preferentially into the octahedral B site and that the hyperfine fields at both A and B sites decrease with increase in Cr concentration. Based on the cation distribution obtained from fitting Mössbauer spectra, structural parameters such as lattice parameters, site bond and edge lengths, and the oxygen parameter u have been calculated. The trend of theoretically calculated lattice parameter with Cr content matches well with the experimentally obtained values.

Sharma, Ram Kripal; Sebastian, Varkey; Lakshmi, N.; Venugopalan, K.; Reddy, V. Raghavendra; Gupta, Ajay

2007-04-01

116

Magnetic properties of Ba-ferrite powders prepared by surfactant assisted ball milling  

SciTech Connect

Magnetic properties of Ba-ferrite processed by a novel method: surfactant assisted low energy ball milling, are discussed. By using cationic and anionic surfactants at pH values above and below the point of zero charge of the oxide surface, some remarkable changes in magnetic properties of the milled material are produced. Vibrating sample magnetometry (VSM) and ferromagnetic resonance are applied for sample evaluation. Directly after milling the particles are in the submicron range with a narrow size distribution. By application of an annealing procedure in air or vacuum to prepared powders changes were observed. Final annealing in air of the samples annealed first in vacuum produces Ba-ferrite powder with m{sub o}M{sub s} and H{sub c} values in a remarkably broad range 0.457--0.564 T, and 136--195 kA/m respectively.

Kaczmarek, W.A.; Ninham, B.W. [Australian National Univ., Canberra (Australia). Research School of Physical Sciences and Engineering

1994-03-01

117

Preparation and microwave absorption properties of barium ferrite nanorods  

Microsoft Academic Search

Barium hexaferrite nanorods were successfully prepared using a sol–gel technique with polymethylmethacrylate as a template. The magnetic nanorods with diameters about 60nm and lengths about 300nm are visible from FESEM images. The electromagnetic parameters of BaFe12O19 with different shapes were measured with vector network analyzer at 5–15GHz. The results show that the microwave absorption properties of rod-shaped BaFe12O19 are better

Guohong Mu; Na Chen; Xifeng Pan; Haigen Shen; Mingyuan Gu

2008-01-01

118

Preparation and characterization of monodisperse Fe nanoparticles.  

SciTech Connect

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.

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

2003-06-01

119

Controlled synthesis of magnetic spinel-type nickel ferrite nanoparticles by the interface reaction and hydrothermal crystallization  

Microsoft Academic Search

Nearly mono-dispersed nickel ferrite nanoparticles have been synthesized by a solid-liquid interface reaction of Ni2+Fe23+–oleate complex with alkali solution assisted by hydrothermal crystallization. Chemical reactions took place at the interface of the solid and liquid phase and the generated particles were then dispersed into the aqueous solution through Brownian movement. The obtained samples were characterized by X-ray diffraction and transmission

Lei Wang; Jiawen Ren; Yangang Wang; Xiaohui Liu; Yanqin Wang

2010-01-01

120

Synthesis of Fe–Ni nano-particles by low-temperature hydrogen reduction of mechanically alloyed Ni-ferrite  

Microsoft Academic Search

Fe–Ni nano-particles were synthesized by mechanical alloying and subsequent low-temperature hydrogen reduction of oxide mixtures. First, single-phase nickel ferrite was mechanically synthesized for 30h with steel balls to powder weight ratio of 20 while the milling was operated at 300rpm. The as-milled powder was then placed in contact with hydrogen at 600°C for 1h. Reduction reactions resulted in production of

A. Azizi; S. K. Sadrnezhaad

2009-01-01

121

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

Microsoft Academic Search

We report the oxidation products and qualitative rates for polydisperse FeCo magnetic nanoparticles (MNPs) synthesized using an induction plasma torch. X-ray diffraction (XRD) and TEM showed MNPs to have a thin ferrite shell. Nanopowders were isochronally annealed to promote oxidation and XRD was used to follow the evolution of the FeCo core and the Fe3O4 and FeO oxide shells. Isothermal

K. N. Collier; N. J. Jones; K. J. Miller; Y. L. Qin; D. E. Laughlin; M. E. McHenry

2009-01-01

122

Preparation and characterization of functionalized aluminum nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

123

Method for synthesizing ferrite nanoparticles ~30 nm in diameter on neutral pH condition for biomedical applications  

NASA Astrophysics Data System (ADS)

Nanosized ferrite spherical particles, ~30 nm in diameter as revealed by scanning electron microscopy, were synthesized from an aqueous Fe(OH)2 suspension (pH=7.6-8.0) at 25 °C by oxidizing it with H2O2. The nanoparticles were of a spinel structure of an intermediate between Fe3O4 and ?-Fe2O3, as revealed by x-ray diffraction. Compared to the nanoparticles synthesized by our previous method in which an aqueous solution of Fe2++Fe3+ was oxidized by air (oxygen), the nanoparticles increased in size, from ~10 nm (previous method) to 30 nm. Also saturation magnetization increased, though slightly, from 76 emu/g (previous method) to 80 emu/g (present method). Therefore, the ferrite nanoparticles synthesized by this method will improve the efficiency of magnetic separation. Because synthesis is performed at room temperature and neutral conditions (pH=7.1-7.8), which are compatible with most bioactive molecules (e.g., antibodies and proteins), these molecules will be immobilized onto the surface of the nanoparticles during their syntheses.

Tada, M.; Hatanaka, S.; Sanbonsugi, H.; Matsushita, N.; Abe, M.

2003-05-01

124

Curcumin nanoparticles: preparation, characterization, and antimicrobial study.  

PubMed

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

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

2011-02-15

125

Preparation and CO{sub 2} methanation activity of an ultrafine Ni(II) ferrite catalyst  

SciTech Connect

Ultrafine Ni(II) ferrite (UNF) with 36% Ni{sup 2+} substitution for Fe{sup 2+} in magnetite has been synthesized in order to study its catalytic activity and selectivity toward CO{sub 2} methanation at 300{degrees}C. Ni(II) ferrites were prepared by two different methods: (1) coprecipitation of Ni{sup 2+}, Fe{sup 2+}, and Fe{sup 3+} at 60{degrees}C followed by heating to 300{degrees}C and (2) oxidation of aqueous suspension of Fe{sup 2+} and Ni{sup 2+} hydroxides at 65{degrees}C (oxidation method). The BET surface area of the initial UNF synthesized by coprecipitation was 73 m{sup 2} g{sup {minus}1}, eight times as large as that of the Ni(II) ferrite obtained by the oxidation method (NF; 9 m{sup 2}g{sup {minus}1}). It rapidly decreased to 26 m{sup 2}g{sup {minus}1} by sintering in the initial stage of methanation. The yield of CH{sub 4} obtained on the UNF catalyst was 1.5-6.0 times larger than that on the NF catalyst in a 2-h run of the methanation, depending on a flow rate of reactant H{sub 2}/CO{sub 2} mixed gas. It was found that the selectivity for CH{sub 4} was much improved in UNF (96%) in comparison with NF. XRD and chemical analysis showed that the UNF and NF were transformed to oxygen-deficient ferrite forms during the methanation. On the other hand, the activity for CO formation significantly decreased on UNF, due to the change in the nature of the active site. 34 refs., 8 figs., 3 tabs.

Tsuji, Masamichi; Yoshida, Takashi; Tamaura, Yutaka [Tokyo Inst. of Technology (Japan)] [and others

1996-12-01

126

Preparation of multifunctional nanoparticles and their assemblies.  

PubMed

This article describes the synthesis of multifunctional nanoparticulate systems and a range of organic reactions for modifying the surface functionalities of these particles and their composites. The reactions include surface silanization, amine-azide conversion, azide-alkyne 'click' chemistry, thiol and amine click chemistry and amide coupling. In addition, we discuss a number of relevant nanoparticle preparations to exemplify the interrelationship of these reactions. This system can readily be adapted to produce a wide range of composites with different features, such as fluorescence, magnetism, plasmon resonance and multiple biofunctionalities. PMID:22899335

McCarthy, Sarah A; Davies, Gemma-Louise; Gun'ko, Yurii K

2012-08-16

127

The role of aggregation of ferrite nanoparticles on their magnetic properties.  

PubMed

We have studied the magnetic properties of aggregates of Mn0.5Zn0.5Gd(x)Fe(2-x)O4 ferrite nanoparticles, with x = 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.18, 0.20. The scanning electron microscopy micrographs show significant aggregation of the nanoparticles in all samples. Zero field cooled and field cooled magnetization measurements were conducted on all samples from 400 K down to 5 K. Most zero field cooled curves were found to exhibit the usual behavior but with wide peaked regions. For some x values, the field cooled magnetization was found to increase slowly with decreasing temperature, and becomes nearly constant at low temperatures. The measurements of magnetization versus applied magnetic field were conducted on all samples at 5 K and 305 K in the field range from -15000 to 15000 Oe. At 305 K the magnetization for all samples was observed to saturate, while at 5 K the magnetization did not reach saturation for some values of x. The saturation magnetization values were suggested to be proportional to the size of particles. These results were discussed and suggested to be due to the inter-particle dipolar and exchange interactions between the particles in the aggregates, the large particle size distribution and the surface magnetization effects. PMID:21780381

Obaidat, I M; Issa, B; Haik, Y

2011-05-01

128

Preparation of magnetic chitosan nanoparticles and immobilization of laccase  

Microsoft Academic Search

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

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

2009-01-01

129

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

NASA Astrophysics Data System (ADS)

Conducting silver paste was prepared by using Ag nanoparticles which were synthesized by e-beam irradiation method (from KAERI); its conductivity was comparatively determined with Ag nanoparticles which were prepared by thermolysis method (commercial). The silver nanoparticles with the diameter of approximately 150 nm size prepared by e-beam irradiation were mixed with glass frit and sintered for 1 h at 500 °C. It is presumably concluded that the wt% of silver nanoparticle, size distribution and homogenous dispersibility of Ag nanoparticles in the pastes are the critical factors for the high conductivity of the paste. Among the various wt% of silver nanoparticle in the conducting silver pastes, silver paste with 90 wt% of silver nanoparticle has the highest conductivity as 1.6×104 S cm-1. This conductivity value is 1.6 times higher than the Ag pastes which were prepared with silver nanoparticles obtained by thermolysis method.

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

2010-11-01

130

Simple preparation of nanoparticles coated with carbohydrate-carrying polymers  

Microsoft Academic Search

Nanoparticles bearing carbohydrate chains on the surface can be prepared by the simple diafiltration method. The nanoparticles prepared by the present method displayed high yield, no-aggregation formation, small size, narrow size distribution, and one-step procedure. Also, the high density carbohydrate chains on the particles can be recognized by liver cells.

C. S. Cho; Y. I. Jeong; T. Ishihara; R. Takei; J. U. Park; K. H. Park; A. Maruyama; T. Akaike

1997-01-01

131

Effect of Additional Elements on the Structural Properties, Magnetic Characteristics and Natural Resonance Frequency of Strontium Ferrite Nanoparticles\\/Polymer Composite  

Microsoft Academic Search

Substituted strontium ferrites SrFe12-xMgx\\/2Snx\\/2O19 (x=1 , 2 and 3) were prepared by sol-gel method. X-ray diffraction (XRD), transmission electron microscope (TEM), AC susceptometer, vibrating sample magnetometer (VSM) and vector network analyzer were used to analyze the structure, static and dynamic magnetic properties of the prepared samples. The prepared ferrite particles possess irregular non spherical shape with a broad size distribution.

Ali Ghasemi; Xiaoxi Liu; Akimitsu Morisako

2009-01-01

132

Preparation and microwave absorption properties of Ce-substituted lithium ferrite  

NASA Astrophysics Data System (ADS)

Ce-substituted lithium ferrite, Li0.5CexFe2.5-xO4 (x=0, 0.015 and 0.15), was prepared from metal nitrates and citric acid by the citrate sol gel method. The thermal decomposition process was investigated by TG-DSC. The phase composition and microstructure of Li0.5CexFe2.5-xO4 was characterized by X-ray powder diffraction analysis (XRD) and a transmission electron microscope (TEM). The complex permittivity and complex permeability and microwave absorption properties of Li0.5CexFe2.5-xO4 paraffin wax composite were measured by the transmission/reflection coaxial line method in the range of 2 18 GHz. It is shown that the substitution of cerium ion had a close effect on the properties of Li0.5CexFe2.5-xO4 ferrites. Also, the present investigation demonstrates that microwave absorbers for applications over 15 GHz, with satisfactory reflection loss, of more than -20 dB for specific frequencies, could be obtained by controlling the substituted Ce element.

Sun, Chang; Sun, Kangning

2007-02-01

133

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

Microsoft Academic Search

NiZn- and NiCuZn-ferrite nanoparticles (50-70 nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83 emu\\/g (NiZn) to 91 emu\\/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in

J. C. Aphesteguy; Abel Damiani; Dalmas Digiovanni; S. E. Jacobo

2009-01-01

134

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

Microsoft Academic Search

NiZn- and NiCuZn-ferrite nanoparticles (50–70nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83emu\\/g (NiZn) to 91emu\\/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in the frequency range

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

2009-01-01

135

Preparation and application of silica-coated magnetic nanoparticles  

NASA Astrophysics Data System (ADS)

Silica coated magnetic nanoparticles have been prepared by sign water-in-oil micro emulsion technique, and have been characterized by Transmission Electron Microscopy and e-ray diffractometer. Concanavalin A was covalent immobilized on the surface of silica coated magnetic nanoparticles. Dextran-Rhodamine B could be easily separated from aqueous solutions by the functionalized nanoparticles. The result implied that the preparation route is easy to yield silica coated magnetic nanoparticles which can be modified for the separation of other target biomolecules, cells, and etc.

He, Xiaoxiao; Wang, Kemin; Tan, Weihong; Xiao, Dan; Yang, Xiaohai; Li, Jun

2001-09-01

136

Mössbauer effect studies on mixed lithium zinc ferrites prepared by solution combustion method  

NASA Astrophysics Data System (ADS)

Mössbauer effect studies have been made on lithium ferrites of varying compositions i.e. Li0.5 - x/2Zn x Mn0.05Fe2.45 - x/2O4 prepared by combustion method from stoichiometric aqueous solutions of metal nitrates and oxalyl dihydrazide. In these compositions x varies from 0?0.5 in steps of 0.1. The Mössbauer spectral studies reveal that substitution of nonmagnetic Zn2 + is responsible for successive increase in line-width and change in hyperfine fields at A and B sites. The combustion method is rapid and may approach direct conversion from the molecular mixture of precursor solution to the fine particles of oxide product. The process involves highly exothermic redox reaction between metal nitrates and oxalyl dihydrazide solutions.

Dosanjh, H. S.; Randhawa, B. S.; Kumar, Nitendar

2008-04-01

137

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

PubMed Central

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

2012-01-01

138

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

NASA Astrophysics Data System (ADS)

NiZn- and NiCuZn-ferrite nanoparticles (50-70 nm) with the chemical formula Ni0.5 Zn0.5Fe2O4 (NiZn) and Ni0.35Cu0.15Zn0.5Fe2O4 (NiCuZn) were synthesized by a combustion synthesis method. The nanocrystallite of these materials was characterized by structural and magnetic methods. Saturation magnetization increases from 83 emu/g (NiZn) to 91 emu/g (NiCuZn). Magnetic permeability and dielectric permittivity were measured on sintered samples (pellets and toroids) in the frequency range of 1 MHz-1.8 GHz. Reflection losses (RL) for both samples were calculated from complex permeability and permittivity. Cu substitution in NiZn-ferrite enhances permeability and RL. In order to explore microwave-absorbing properties in X-band, magnetic nanoparticles were mixed with an epoxy resin to be converted into a microwave-absorbing composite and microwave behaviors of both materials were studied using a microwave vector network analyzer from 7.5 to 13.5 GHz. Cu substitution diminishes absorption intensity in the range 11.5-12.5 GHz.

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

2009-10-01

139

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

Microsoft Academic Search

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

Xiong Wang; Yan'ge Zhang; Zhibin Wu

2010-01-01

140

Borosilicate nanoparticles prepared by exothermic phase separation  

Microsoft Academic Search

Nanoparticles play an important role in chemical and biological sciences due to their ability to bind and concentrate many molecules on their surface. Polymers and silica are widely used to make nanoparticles, but efforts to make nanoparticles from borosilicate glass—which exhibits high tolerance to chemicals and solvents, combined with excellent mechanical and thermal stability—have proved unsuccessful. Here we show that

Virendra K. Parashar; Jean-Baptiste Orhan; Abdeljalil Sayah; Marco Cantoni; Martin A. M. Gijs

2008-01-01

141

Preparation and Characterization of Gold Nanoparticles with Different Capping Agents  

Microsoft Academic Search

Biocompatible gold nanoparticles have gained considerable attention in recent years for potential applications in bio-diagnostics, gas sensing, catalysis, and nanomedicine due to their interesting size-dependent properties. In the present work a chemical reduction method is used to produce gold nanoparticles with different capping agents. These nanoparticles were prepared by reducing HAuCl4 using citrate and trialanine phosphine (THPAL) and then capping

S. Vijaya Kumar; S. Ganesan

2011-01-01

142

Preparation and characterization of magnetite nanoparticles coated by amino silane  

Microsoft Academic Search

Magnetite nanoparticles were prepared by coprecipitation of Fe2+ and Fe3+ with NH4OH, and then, amino silane was coated onto the surface of the magnetite nanoparticles. Transmission electronic microscopy shows the average size of 7.5 nm in diameter. Powder X-ray diffraction and electronic diffraction measurements show the spinel structure for the magnetite nanoparticles. FT–IR spectra indicate that amino silane molecules have

Ming Ma; Yu Zhang; Wei Yu; Hao-ying Shen; Hai-qian Zhang; Ning Gu

2003-01-01

143

Polyethylene glycol as an alternative polymer solvent for nanoparticle preparation.  

PubMed

Solvent toxicity is one of the major drawbacks in the preparation of polymeric nanoparticles today. Here, polyethylene glycols (PEGs) are proposed as non-toxic solvents for the preparation of polymeric nanoparticles. Based on a preparation process similar to the solvent displacement technique, several process parameters were examined for their effects on the properties of the prepared nanoparticles by this method to achieve the optimum preparation conditions. The investigated parameters included polymer type and concentration, volume and temperature of the dispersing phase, methods of dispersing the solvent phase into the non-solvent phase, duration and speed of stirring and washing by dialysis. Ammonio methacrylate copolymer (Eudragit RL), poly-lactide-co-glycolide (PLGA), and PEG-PLGA were found to be successful polymer candidates for the preparation of nanoparticles by this method. Nanoparticles with diameters ranging from 80 to 400nm can be obtained. The encapsulation efficiencies of bovine serum albumin, and lysozyme as model proteins were ranging from 7.3±2.2% to 69.3±1.8% depending on the strength of polymer-protein interaction. Biological assays confirmed a full lysozyme activity after the preparation process. PEG proved to be a suitable non-toxic solvent for the preparation of polymeric protein-loaded nanoparticles, maintaining the integrity of protein. PMID:23958752

Ali, Mohamed Ehab; Lamprecht, Alf

2013-08-16

144

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

Microsoft Academic Search

Ni0.6Zn0.4Fe2O4 ferrite nano-particles with a crystallite size of about 20nm were prepared by the conventional hydrothermal method, followed by annealing in a microwave oven for 7.5–15min. 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

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

2011-01-01

145

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

SciTech Connect

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

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

2005-12-08

146

Regio- and chemoselective reduction of nitroarenes and carbonyl compounds over recyclable magnetic ferrite-nickel nanoparticles (Fe(3)O(4)-Ni) by using glycerol as a hydrogen source.  

PubMed

Reduction by magnetic nano-Fe(3)O(4)-Ni: a facile, simple and environmentally friendly hydrogen-transfer reaction that takes place over recyclable ferrite-nickel magnetic nanoparticles (Fe(3)O(4)-Ni) by using glycerol as hydrogen source allows aromatic amines and alcohols to be synthesized from the precursor nitroarenes and carbonyl compounds. PMID:22933355

Gawande, Manoj B; Rathi, Anuj K; Branco, Paula S; Nogueira, Isabel D; Velhinho, Alexandre; Shrikhande, Janhavi J; Indulkar, Utkarsha U; Jayaram, Radha V; Ghumman, C Amjad A; Bundaleski, Nenad; Teodoro, Orlando M N D

2012-08-30

147

Preparation of magnetic polymeric composite nanoparticles by seeded emulsion polymerization  

Microsoft Academic Search

Seeded emulsion polymerization was used to prepare magnetic polymeric composite nanoparticles (MPCNPs) with the aim to successfully encapsulate magnetite particles and to improve particle size distribution (PSD). Microscopical morphology and number-average diameter of hydrophilic magnetite particles (HMPs), magnetic seed latex nanoparticles (MSLNPs) and MPCNPs were observed and analyzed by transmission electron microscope (TEM). Weight-average diameter and PSD of MSLNPs and

Shulai Lu; Rongjun Qu; Jacqueline Forcada

2009-01-01

148

Preparation and structural properties of Pd nanoparticles in layered silicate  

Microsoft Academic Search

Pd nanocrystals in the 5–15 nm ranges were prepared on pillared clay minerals (PILCs) as supports by immobilizing Pd nanoparticles in the interlamellar space of montmorillonite and saponite by pillaring with aluminium hydroxide cations. Pd nanoparticles were generated via reduction by ethanol of Pd acetate present in the adsorption layer at room temperature. The structure of Pd-PILC samples was characterized

Anna Sz?cs; Ferenc Berger; Imre Dékány

2000-01-01

149

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

Microsoft Academic Search

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

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

2011-01-01

150

Growth and characterization of ferrite film prepared by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Ba2+Fe12O19 (BaO.6Fe2O3) films have been grown on (0001) sapphire substrate using pulsed laser deposition (PLD) technique. Prepared films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), atomic force microscopy (AFM) and magnetic measurements. XRD confirms the formation of Ba2+Fe12O19 phase, whereas presence of Fe2O3 was also identified. X-ray photoelectron spectroscopy (XPS) shows the signature of all the elements present in the barium ferrite. XRR data show the thickness of the film is ~ 24.2 nm with top layer roughness of ~ 3.7 nm. AFM measurement suggests the formation of clusters with average roughness of ~ 3.9 nm. Magnetic measurements of the target reveal its anisotropic nature with coercivity values: 0.23 and 0.24 T, obtained along two orthogonal directions. For the prepared thin film, the obtained coercivity ~80 mT and saturation induction 0.13 T are lower than the usual values obtained for Ba2+Fe12O19 compound (coercivity and saturation induction values are 0.19 Tesla and 0.48 T respectively), can be ascribed to the presence of Fe2O3 phase.

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

2012-05-01

151

Preparation of Magnetic Chitosan Nanoparticles for Diverse Biomedical Applications  

NASA Astrophysics Data System (ADS)

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

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

152

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

Microsoft Academic Search

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

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

2005-01-01

153

Evidence for polaron conduction in nanostructured manganese ferrite  

Microsoft Academic Search

Nanoparticles of manganese ferrite were prepared by the chemical co-precipitation technique. The dielectric parameters, namely, real and imaginary dielectric permittivity (?' and ?''), ac conductivity (sigmaac) and dielectric loss tangent (tandelta), were measured in the frequency range of 100 kHz-8 MHz at different temperatures. The variations of dielectric dispersion (?') and dielectric absorption (?'') with frequency and temperature were also

E. Veena Gopalan; K. A. Malini; S. Saravanan; D. Sakthi Kumar; Yasuhiko Yoshida; M. R. Anantharaman

2008-01-01

154

Evidence for polaron conduction in nanostructured manganese ferrite  

Microsoft Academic Search

Nanoparticles of manganese ferrite were prepared by the chemical co-precipitation technique. The dielectric parameters, namely, real and imaginary dielectric permittivity (?? and ??), ac conductivity (?ac) and dielectric loss tangent (tan?), were measured in the frequency range of 100 kHz–8 MHz at different temperatures. The variations of dielectric dispersion (??) and dielectric absorption (??) with frequency and temperature were also

E Veena Gopalan; K A Malini; S Saravanan; D Sakthi Kumar; Yasuhiko Yoshida; M R Anantharaman

2008-01-01

155

Photoacoustic Measurement of Thermal Properties of Co-Ni-Li Ferrite Nanoparticles  

NASA Astrophysics Data System (ADS)

A simple home-made open photoacoustic cell is used for measuring some of the thermal properties of nanoparticles of {Co}_{0.5}{Ni}_{0.5{- }2{x}}{Li}_x{ Fe }_{2+{x}}{O}4 (with x ranging from 0.00 to 0.25 in steps of 0.05) prepared by the citrate precursor method. The influence of sintering temperatures on the thermal properties of a selected sample for x=0.25 was also investigated. The thermal-diffusivity and thermal-effusivity measurements of the investigated samples are obtained by measuring the photoacoustic signal as a function of the modulated frequency depending on the existence of a reference sample. The thermal diffusivity of the as-prepared samples decreases as the {Li}^{1+} content increases except for the samples for x=0.15 and x=0.20. These exceptions may be due to a better magnetic ordering in these samples leading to reduced phonon scattering and a higher thermal diffusivity. Finally, the thermal diffusivity of the sintered samples increases as the sintering temperature increases due to the increase in grain size.

Abosheiasha, H. F.; Assar, S. T.; El Nimr, M. K.

2013-06-01

156

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

157

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

SciTech Connect

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

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

2009-02-04

158

Magnetic properties of nanoparticles of cobalt ferrite at high magnetic field  

Microsoft Academic Search

In this paper we report high magnetic field (? 140 ? H ? 140 kOe) magnetization data for cobalt ferrites (crystallites size ? 42 nm) for temperatures (T) varying from 5 to 340 K. The T-dependence for the cubic magnetocrystalline anisotropy constant K1 was determined by using the “law of approach” (LA) to saturation. The values of K1 were found

A. Franco; F. L. A. Machado; V. S. Zapf

2011-01-01

159

Magnetic properties of nanoparticles of cobalt ferrite at high magnetic field  

Microsoft Academic Search

In this paper we report high magnetic field (- 140 <= H <= 140 kOe) magnetization data for cobalt ferrites (crystallites size ~ 42 nm) for temperatures (T) varying from 5 to 340 K. The T-dependence for the cubic magnetocrystalline anisotropy constant K1 was determined by using the ``law of approach'' (LA) to saturation. The values of K1 were found

A. Franco; F. L. A. Machado; V. S. Zapf

2011-01-01

160

The effects of La–Zn substitution on the magnetic properties of Sr-magnetoplumbite ferrite nano-particles  

Microsoft Academic Search

The La–Zn substituted Sr-Magnetoplumbite ferrite LaxSr1?xZnxFe12?xO19 (x=0–0.6) fine particles were prepared to investigate the effects of the substitution on the magnetic properties of the samples. It is observed, with increasing substitution rate, that the saturation magnetization Ms as well as the magnetocrystalline anisotropy constant KU1 increased up to a maximum for about x=0.3, then decreased rapidly. The value of dHc\\/dT

Jianmin Bai; Xiaoxi Liu; Tian Xie; Fulin Wei; Zheng Yang

2000-01-01

161

Magnetic Nanoparticle Arrays prepared via Coaxial Electrospinning  

NASA Astrophysics Data System (ADS)

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 the process renders a coaxial delivery mechanism that facilitates the construction of nanoparticle arrays. These hybrid 1D nanomaterials were structurally characterized by electron microscopy and the magnetic characteristics of these fiber encapsulated particle arrays were studied using vibrating sample magnetometry. Anisotropic magnetic behavior along different orthogonal axes (parallel and perpendicular) was observed even at room temperature with an appreciable increase in coercivity in the perpendicular configuration. Experimental work is underway to use these particle arrays as precursor materials for the creation of magnetite nanorods.

Sharma, Nikhil; Jaffari, Hassnain; Shah, Ismat; Pochan, Darrin

2009-03-01

162

Preparation of Silicide Nanoparticles by Induction Thermal Plasmas  

Microsoft Academic Search

The purpose of this paper is to prepare nanoparticles of silicon base intermetallic compounds by induction thermal plasmas. The properties of the prepared particles are affected by the vapor pressure ratio of the constituent metals. The condensation mechanism of metal mixture in thermal plasmas was investigated experimentally and numerically. Silicon powder premixed with metal powder (Mo, Ti, Co, Fe, Cr,

Takayuki Watanabe

163

Surfactant-assisted preparation of hexagonal molybdenum disulfide nanoparticles  

Microsoft Academic Search

The hexagonal MoS2 nanoparticles were prepared using a surfactant-assisted method in aqueous solution at 373 K. The as-obtained samples were characterized by XRD, IR and TEM equipped with EDS. It was found that the as-prepared samples had hexagonal structures with size of 100–200 nm. The possible reaction route and formation mechanism were proposed.

Zhuangzhi Wu; Dezhi Wang; Aokui Sun

2009-01-01

164

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

NASA Astrophysics Data System (ADS)

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

Pulišová, P.; Ková?, J.; Voigt, A.; Raschman, P.

2013-09-01

165

On the Preparation of Single Crystal Ferrite Materials by the Floating Zone Technique.  

National Technical Information Service (NTIS)

The growth of single crystal ferrites, by the floating zone technique, was extensively investigated. A pressure vessel, incorporating a floating zone mechanism was constructed; also, appropriate facilities were provided for high frequency induction heatin...

D. A. Lepore R. C. Puttbach

1964-01-01

166

Novel method for the preparation of explosive nanoparticles  

NASA Astrophysics Data System (ADS)

We report the preparation of explosives nanoparticles of RDX and TNT in a variety of substrates that include glass, silicon and stainless steel. The explosive nanoparticles were prepared by means of pneumatically assisted nebulization (PAN) using an electrospray (ESI) needle, which allowed for the direct deposit of the energetic material onto the substrate. The deposited nanoparticles were characterized by optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX) and Raman Microscopy. SEM micrographs showed that the process produced particles with a mean size in the range of 80-500 nm and a narrow size distribution. For TNT, the process produced smaller particles with a narrower size distribution. The EDX spectrum showed the presence of carbon, nitrogen and oxygen consistent with the elemental composition of the energetic materials. The chemical properties of the nanoparticles were also determined by vibrational spectroscopy.

Barreto-Cabán, Marcos A.; Pacheco-Londoño, Leonardo; Ramírez, Michael L.; Hernández-Rivera, Samuel P.

2006-06-01

167

Preparation and evaluations in vitro of oxaliplatin polylactic acid nanoparticles.  

PubMed

The oxaliplatin nanoparticles were prepared with polylactic acid matrix, orthogonal test was applied to optimize the prescriptions, and the qualities of oxaliplatin nanoparticles were characterized by the shape, particle size, encapsulation efficiency (EE), and drug loading (DL). Oxaliplatin nanoparticle was prepared by solution replacement method. The formation of 0.25% Tween80, DMF-water 1:8 (v/v), oxaliplatin-polylactic acid 1:5 (w/w), and 20 mg/ml polylactic acid showed the suitable EE (17.4 ± 0.47%), DL (3.52 ± 0.07%). We observed the shape of oxaliplatin nanoparticles through SEM. The average size of the particles was 120.5 ± 8.7 nm, which was detected by N5 submicron particle size analyzer. PMID:23305166

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

2013-01-10

168

Nanostructured bismuth ferrites synthesized by solvothermal process  

Microsoft Academic Search

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

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

2010-01-01

169

Preparation of magnetic fluorescent hollow nanoparticles with multi-layer  

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

170

Synthesis and characterization of polymer nanocomposites containing magnetic nanoparticles  

Microsoft Academic Search

Magnetic poly(methyl methacrylate) nanocomposites were prepared using oleic acid coated cobalt ferrite and magnetite nanoparticles. Both nanofillers had a similar effect in shifting the glass transition temperature from that of the neat polymer. The cobalt ferrite nanocomposite had magnetic hysteresis at 2 and 300 K and the magnetite nanocomposite had magnetic hysteresis at 2 K and superparamagnetic behavior at 300

Edwin de La Cruz-Montoya; Carlos Rinaldi

2010-01-01

171

Preparation of silver nanoparticles using tryptophan and its formation mechanism  

Microsoft Academic Search

A non-toxic route was used for the preparation of silver nanoparticles using tryptophan (Trp) as reducing\\/stabilizing agent in the presence of cetyltrimethyl ammonium bromide (CTAB). Role of water soluble neutral polymer poly(vinylpyrrolidone) (PVP) has been studied on the growth of yellow colour silver nanoparticle formation. The synthesized nanostructures were characterized by UV–Visible absorption spectroscopy, transmission electron microscopy (TEM) by observing

Zoya Zaheer; Maqsood Ahmad Malik; F. M. Al-Nowaiser; Zaheer Khan

2010-01-01

172

Supported ruthenium nanoparticles on polyorganophosphazenes: preparation, structural and catalytic studies  

Microsoft Academic Search

Supported Ru nanoparticles on a number of polyorganophosphazenes were prepared and tested for the hydrogenation of unsaturated compounds. The complex Ru(?6-cycloocta-1,3,5-triene)(?4-cycloocta-1,5-diene) was found to be a suitable precursor to deposit metallic nanoparticles on polyorganophosphazenes; upon the removal of cycloolefin ligands under hydrogen atmosphere, highly dispersed metal particles on the polymeric support can be obtained. Ru on polydimethylphosphazene was found to

Andrea Spitaleri; Paolo Pertici; Nico Scalera; Giovanni Vitulli; Manh Hoang; Terence W Turney; Mario Gleria

2003-01-01

173

Preparation of size-controlled nanoparticles of magnetite  

NASA Astrophysics Data System (ADS)

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.

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

2012-05-01

174

Preparation of alpha-elastin nanoparticles by gamma irradiation  

NASA Astrophysics Data System (ADS)

Nanoparticles were prepared by utilizing the thermosensitive aggregation of alpha-elastin and gamma ray crosslinking. Three different heating process, “Slow heating”, “Fast heating”, and “Heat shock”, were applied for the aggregation of the alpha-elastin and examined to yield nanoparticles by gamma rays crosslinking. As a result, only “Slow heating” process yielded nanoparticles with diameters of about ca. 300 nm above cloud point (CP) and about ca. 100 nm below CP, and a narrow size distribution above 1.0 mg/ml concentration (exclude 1.0 mg/ml).

Fujimoto, Mari; Okamoto, Kouji; Furuta, Masakazu

2009-12-01

175

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

PubMed Central

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

Bregar, Vladimir B; Lojk, Jasna; Sustar, Vid; Veranic, Peter; Pavlin, Mojca

2013-01-01

176

Mössbauer Studies on Nanosized Rubidium Ferrite (RbFeO2) Prepared by Thermal Decomposition of Rubidium Ferrioxalate Precursor using Precursor Method  

NASA Astrophysics Data System (ADS)

Pure, nanosized rubidium ferrites (RbFeO2) has been prepared from the thermolysis of rubidium trioxalatoferrate (III), Rb3[Fe(C2O4)3].3H2O. Various physico-chemical techniques i.e. Simultaneous TG-DTG, XRD & Mössbauer spectroscopy have been employed for the characterization of intermediates/products formed. Nanosized ferrites are formed at much lower temperature and in less time as compared to that of the conventional ceramic method. Magnetic properties for the ferrite product were also carried out.

Gupta, Manik; Randhawa, B. S.

2011-12-01

177

Combustion synthesis of Cobalt ferrite Nanoparticles–Influence of fuel to oxidizer ratio  

Microsoft Academic Search

The effect of fuel characteristics on the processing of nano-sized Cobalt ferrite fine powders by the combustion technique is reported. By using different combinations of glycine fuel and metal nitrates, the adiabatic flame temperature (Tad) of the process as well as product characteristics could be controlled easily. Thermodynamic modelling of the combustion reaction shows that as the fuel-to-oxidant ratio increases,

A. B. Salunkhe; V. M. Khot; M. R. Phadatare; S. H. Pawar

178

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

PubMed

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

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

2012-11-01

179

The surface chemistry and stability of gold nanoparticles prepared using methanol extract of Eucalyptus camaldulensis  

Microsoft Academic Search

The development of nontoxic, clean techniques for synthesising metal nanoparticles such as gold has attracted increasing attention in recent years. Many reports have been published about the synthesis of gold nanoparticles using plant extracts. However, the stability of these prepared gold nanoparticles has not been investigated. In this research, the stability of gold nanoparticles prepared by Eucalyptus camaldulensis was investigated

Valiolah Elyasi Golmoraj; Mohammad Reza Khoshayand; Mohsen Amini; Kamyar Mollazadeh Moghadamd; Gholamreza Amin; Ahmad Reza Shahverdi

2011-01-01

180

Preparation of size-controlled bovine serum albumin (BSA) nanoparticles by a modified desolvation method  

Microsoft Academic Search

The size effect of nanomaterials is of major interest, since it may affect their bioavailability and toxicity. In this study, bovine serum albumin (BSA) nanoparticles were prepared using a modified desolvation method. Bare BSA nanoparticles and calcium (Ca)-loaded BSA nanoparticles were fabricated at the targeted sizes, 100, 400, and 800nm. The mean diameters of the prepared BSA nanoparticles were 125,

Ji Yeon Jun; Hoang Hai Nguyen; Sae-Yeol-Rim Paik; Hyang Sook Chun; Byeong-Cheol Kang; Sanghoon Ko

2011-01-01

181

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

Microsoft Academic Search

One of the main advantages of gene therapy over traditional therapy is the potential to target the expression of therapeutic genes in desired cells or tissues. To achieve targeted gene expression, we developed a novel heat-inducible gene expression system in which thermal energy generated by Mn–Zn ferrite magnetic nanoparticles (MZF-NPs) under an alternating magnetic field (AMF) was used to activate

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

2008-01-01

182

Preparation and Properties of Various Magnetic Nanoparticles  

PubMed Central

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

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

2009-01-01

183

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

184

Development of phosphonate modified Fe (1? x) Mn x Fe 2O 4 mixed ferrite nanoparticles: Novel peroxidase mimetics in enzyme linked immunosorbent assay  

Microsoft Academic Search

A highly facile and feasible strategy on the fabrication of advanced intrinsic peroxidase mimetics based on Mn2+ doped mixed ferrite (MnIIxFeII1?xFeIII2O4) nanoparticles was demonstrated for the quantitative and sensitive detection of mouse IgG (as a model analyte). Mn2+ doped Fe1?xMnxFe2O4 nanoparticles were synthesized using varying ratios of Mn2+:Fe2+ ions and characterized by the well known complementary techniques. The increase of

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

2011-01-01

185

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

PubMed

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

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

2011-09-16

186

Preparation and Magnetic Properties of NiFe2O4 Nanoparticles by Modified Pechini Method  

Microsoft Academic Search

Nickel ferrite (NiFe2O4) nanoparticles have been synthesized by modified Pechini method in the presence of surfactant and certain amount of concentrated nitric acid. The obtained foamed gel precursors were characterized by TG\\/DTA to determine the thermal decomposition and subsequently were calcined at different temperatures in the range of 500–800°C for 2 h to obtain NiFe2O4 nanoparticles which were characterized by X-ray

Xian-ming Liu; Wen-Liang Gao

2011-01-01

187

Preparation and Magnetic Properties of NiFe2O4 Nanoparticles by Modified Pechini Method  

Microsoft Academic Search

Nickel ferrite (NiFe2O4) nanoparticles have been synthesized by modified Pechini method in the presence of surfactant and certain amount of concentrated nitric acid. The obtained foamed gel precursors were characterized by thermogravimetry-differential thermal analysis (TG-DTA) to determine the thermal decomposition and subsequently calcined at different temperatures in the range of 500--800°C for 2 h to obtain NiFe2O4 nanoparticles, which were characterized

Xian-ming Liu; Wen-Liang Gao

2012-01-01

188

Synthesis and Magnetic Properties of New Multi-components Spinel Ferrite Nanoparticles  

Microsoft Academic Search

We synthesized new multi-components spinel ferrite including Ni, Mn, Zn, Co, and Fe in order to improve the magnetic properties in nanosized particles by using a chemical coprecipitation method. The samples were synthesized in the mole ratios of MxMyFe(1_x+y)OldrFe2O3 (Mx My=Ni, Mn, Zn, Co, 0

Seiichi Sugimoto; K. Yagi; Y. Harada; M. Tokuda

2007-01-01

189

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

190

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

Microsoft Academic Search

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

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

2006-01-01

191

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

SciTech Connect

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

Joseyphus, R. Justin [Graduate School of Environmental Studies, Tohoku University, AramakiAza Aoba-ku, Sendai 980-8579 (Japan); Materials Science Centre, Dept. of Nuclear Physics, University of Madras, Guindy Campus, Chennai-25 (India); Narayanasamy, A. [Materials Science Centre, Dept. of Nuclear Physics, University of Madras, Guindy Campus, Chennai-25 (India); Jeyadevan, B.; Shinoda, K.; Tohji, K. [Graduate School of Environmental Studies, Tohoku University, AramakiAza Aoba-ku, Sendai 980-8579 (Japan)

2006-05-15

192

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

PubMed Central

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

2012-01-01

193

Multiferroic bismuth ferrite material core based inductive displacement sensor  

NASA Astrophysics Data System (ADS)

In this research, an inductive displacement sensor with multiferroic bismuth ferrite core has been realized. The bismuth ferrite sample is synthesized and its structural and dielectric properties are studied. A rod-shaped bismuth ferrite core is prepared and displaced through the inductor of a RLC circuit. The performance of the prepared bismuth ferrite core has been compared with a commercially available ferrite core.

Rajeswari, R.; Biswal, M. R.; Nanda, J.; Mishra, N. C.

2012-07-01

194

Influence of aging time of oleate precursor on the magnetic relaxation of cobalt ferrite nanoparticles synthesized by the thermal decomposition method  

NASA Astrophysics Data System (ADS)

Cobalt ferrite nanoparticles are of interest because of their room temperature coercivity and high magnetic anisotropy constant, which make them attractive in applications such as sensors based on the Brownian relaxation mechanism and probes to determine the mechanical properties of complex fluids at the nanoscale. These nanoparticles can be synthesized with a narrow size distribution by the thermal decomposition of an iron-cobalt oleate precursor in a high boiling point solvent. We studied the influence of aging time of the iron-cobalt oleate precursor on the structure, chemical composition, size, and magnetic relaxation of cobalt ferrite nanoparticles synthesized by the thermal decomposition method. The structure and thermal behavior of the iron-cobalt oleate was studied during the aging process. Infrared spectra indicated a shift in the coordination state of the oleate and iron/cobalt ions from bidentate to bridging coordination. Aging seemed to influence the thermal decomposition of the iron-cobalt oleate as determined from thermogravimmetric analysis and differential scanning calorimetry, where shifts in the temperatures corresponding to decomposition events and a narrowing of the endotherms associated with these events were observed. Aging promoted formation of the spinel crystal structure, as determined from X-ray diffraction, and influenced the nanoparticle magnetic properties, resulting in an increase in blocking temperature and magnetocrystalline anisotropy. Mossbauer spectra also indicated changes in the magnetic properties resulting from aging of the precursor oleate. Although all samples exhibited some degree of Brownian relaxation, as determined from complex susceptibility measurements in a liquid medium, aging of the iron-cobalt oleate precursor resulted in crossing of the in-phase ??and out-of-phase ?? components of the complex susceptibility at the frequency of the Brownian magnetic relaxation peak, as expected for nanoparticles that relax through a single relaxation mechanism. The resulting nanoparticles would be suitable for sensors based on the Brownian relaxation mechanism and in determining mechanical properties of complex fluids at the size scale of the nanoparticles.

Herrera, Adriana P.; Polo-Corrales, Liliana; Chavez, Ermides; Cabarcas-Bolivar, Jari; Uwakweh, Oswald N. C.; Rinaldi, Carlos

2013-02-01

195

Monitoring colloidal stability of polymer-coated magnetic nanoparticles using AC susceptibility measurements  

Microsoft Academic Search

The application of the response of magnetic nanoparticles to oscillating magnetic fields to probe transitions in colloidal state and structure of polymer-coated nanoparticles is demonstrated. Cobalt ferrite nanoparticles with narrow size distribution were prepared and shown to respond to oscillating magnetic fields through a Brownian relaxation mechanism, which is dependent on the mechanical coupling between the particle dipoles and the

Adriana P. Herrera; Carola Barrera; Yashira Zayas; Carlos Rinaldi

2010-01-01

196

Mössbauer and magnetization studies of nickel ferrite nanoparticles synthesized by the microwave-combustion method  

NASA Astrophysics Data System (ADS)

Nanocrystalline nickel ferrite was synthesized from its stoichiometric metal nitrates and urea mixtures, using a microwave assisted combustion method. The process was a convenient, inexpensive and an efficient method for formation of NiFe2O4 nanomaterials. Effect of urea/metal nitrates ratio on the obtained phases, particle size and magnetic properties has been investigated by various techniques. Saturation magnetization of 50 emu/g was observed at room temperature for larger particles, and it decreases with decreasing particle size. The coercivity attains a maximum value of 170 Oe when the particle size was ~20 nm, and decreases with increasing particle size. Mössbauer spectra measured at RT for some representative samples show a combination of ordered and superparamagnetic behavior, whereas those collected at 20 K elucidate the nature of the obtained phases and cation distribution.

Mahmoud, M. H.; Elshahawy, A. M.; Makhlouf, Salah A.; Hamdeh, H. H.

2013-10-01

197

Magnetic hyperthermia investigation of cobalt ferrite nanoparticles: Comparison between experiment, linear response theory, and dynamic hysteresis simulations  

NASA Astrophysics Data System (ADS)

Considerable effort has been made in recent years to optimize materials properties for magnetic hyperthermia applications. However, due to the complexity of the problem, several aspects pertaining to the combined influence of the different parameters involved still remain unclear. In this paper, we discuss in detail the role of the magnetic anisotropy on the specific absorption rate of cobalt-ferrite nanoparticles with diameters ranging from 3 to 14 nm. The structural characterization was carried out using x-ray diffraction and Rietveld analysis and all relevant magnetic parameters were extracted from vibrating sample magnetometry. Hyperthermia investigations were performed at 500 kHz with a sinusoidal magnetic field amplitude of up to 68 Oe. The specific absorption rate was investigated as a function of the coercive field, saturation magnetization, particle size, and magnetic anisotropy. The experimental results were also compared with theoretical predictions from the linear response theory and dynamic hysteresis simulations, where exceptional agreement was found in both cases. Our results show that the specific absorption rate has a narrow and pronounced maxima for intermediate anisotropy values. This not only highlights the importance of this parameter but also shows that in order to obtain optimum efficiency in hyperthermia applications, it is necessary to carefully tailor the materials properties during the synthesis process.

Verde, E. L.; Landi, G. T.; Gomes, J. A.; Sousa, M. H.; Bakuzis, A. F.

2012-06-01

198

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

NASA Astrophysics Data System (ADS)

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

Ibrahim, E. M. M.

2013-04-01

199

Fabrication and swimming properties of micro-machine coated with magnetite prepared by ferrite plating  

NASA Astrophysics Data System (ADS)

By the sterolithography technique and the ferrite plating, we have fabricated a magnetic micro-machine which coated Fe3O4. The sterolithography technique enables to form the spiral-shape resinous templates and the ferrite plating enables to coat Fe3O4 uniformly onto these templates from an aqueous solution. The total machine weight is light because a resin of the template body is almost the same density as water. We have verified that the machines swim freely and wirelessly in water by applying a rotational magnetic field. As the machine coated with Fe3O4 has a biocompatibility, there is a possibility of medical micro-robots which swim in human body for medical operations.

Nishimura, K.; Sendoh, M.; Ishiyama, K.; Arai, K. I.; Uchida, Hironaga; Inoue, Mitsuteru

2004-06-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2013-02-01

201

Effect of annealing in a reductive environment on the magnetic properties of barium ferrite nanoparticles doped with Ti4+ and Co2+  

NASA Astrophysics Data System (ADS)

It was found experimentally that the annealing of BaFe10.6Co0.7Ti0.7O19 and BaFe10.2Co0.9Ti0.9O19 complex magnetic oxide nanoparticles in paraffin vapor irreversibly increases their coercive force H c and saturation magnetization M s to the H c and M s values for barium ferrite BaFe12O19. The annealing of these nanoparticles, and of particles of magnetic oxides CrO2, ?-Fe2O3, and BaFe12O19 in air and in paraffin vapor, has not been shown to affect their H c and M s values. An explanation in terms of diffusion self-purification of nanoparticles from ion impurities activated by chemical processes on their surface is offered.

Petinov, V. I.

2011-10-01

202

NiZn ferrite thin films prepared by Facing Target Sputtering  

Microsoft Academic Search

NiZn ferrite thin films with spinel structure have been deposited successfully on glass substrates at a relatively low temperature by means of the Facing Target Sputtering (FTS) technique. In addition to substrate temperature, PO2\\/P (O2 partial pressure over total sputtering pressure) ratio was found to be another major factor in controlling the in-plane coercivity Hc and saturation moment density Ms

Zhenghong Qian; Geng Wang; J. M. Sivertsen; J. H. Judy

1997-01-01

203

Preparation and structural characterization of bismuth ferrite crystals of different morphological types  

Microsoft Academic Search

We have studied conditions for bismuth ferrite, BiFeO3, crystallization from off-stoichiometric Bi2O3-Fe2O3 melts, obtained crystals of different morphological types (dendritic and faceted pseudocubic) up to 3 mm in size, and characterized\\u000a them by a variety of techniques (X-ray diffraction, IR spectroscopy, differential thermal analysis, X-ray structure analysis,\\u000a and X-ray microanalysis).

L. P. Kozeeva; M. Yu. Kameneva; N. V. Podberezskaya; A. I. Smolentsev; V. E. Fedorov

2011-01-01

204

Preparation of Fe3O4 Films by Light-Enhanced Ferrite Planing  

Microsoft Academic Search

Polycrystalline Fe3O4 films were plated on glass substrates in an aqueous solution. By irradiating the substrate surface with an Xe lamp at power density of ~450 W\\/cm2, the deposition rate of Fe3O4 film was increased by a factor of about 10 (from ~30 nm\\/min to ~320 nm\\/min). With light irradiation times as short as 4 min, we obtained ferrite films

T. Itoh; S. Hori; M. Abe; Y. Tamaura

1991-01-01

205

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles  

PubMed Central

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

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

2010-01-01

206

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

Microsoft Academic Search

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

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

2003-01-01

207

Macroscopic Quantum Tunneling of Magnetization of Single Ferrimagnetic Nanoparticles of Barium Ferrite  

Microsoft Academic Search

Presented are switching field measurements of individual ferrimagnetic and insulating BaFeCoTiO nanoparticles containing about 105muB at very low temperatures (0.1-6 K). For temperatures higher than 0.4 K, the quantitative agreement with the Néel-Brown theory of thermal activated magnetization reversal allowed us to identify unambiguously the magnetization reversal of uniform rotation. Below 0.4 K, strong deviations from this model are evidenced

W. Wernsdorfer; E. Bonet Orozco; K. Hasselbach; A. Benoit; D. Mailly; O. Kubo; H. Nakano; B. Barbara

1997-01-01

208

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

PubMed

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

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

2013-02-19

209

The role of copper ions on the structural and magnetic characteristics of MgZn ferrite nanoparticles and thin films  

NASA Astrophysics Data System (ADS)

In this study CuxMg0.5-xZn0.5Fe2O4 (x=0-0.5) nanoparticles and thin films were prepared by sol-gel processing. The morphologies of nanoparticles were observed by transmission electron microscope (TEM). The Mössbauer spectroscopy (MS) was employed to determine the site preference of the constitutive elements. Magnetic dynamics of the nanoparticles was studied by the measurement of AC magnetic susceptibility versus temperature at different frequencies. The phenomenological Néel-Brown and Vogel-Fulcher models were employed to distinguish between interacting or non-interacting system. Results exhibited that there is strong interaction between fine particles. X-ray diffraction (XRD) patterns of the thin films indicate the formation of single-phase cubic spinel structure. Atomic force microscope (AFM) was employed to evaluate the surface morphologies of the prepared thin films. Vibrating sample magnetometer (VSM) was employed to probe magnetic properties of samples. It was found that with an increase in the amount of copper, the saturation of magnetization and initial permeability increase.

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

2010-10-01

210

Preparation of NiZn ferrite/SiO2 nanocomposite powders by sol-gel auto-combustion method  

NASA Astrophysics Data System (ADS)

A nitrate-citrate-silica gel was prepared from metallic nitrates, citric acid and silica powder by sol-gel process, and it was further used to synthesize Ni0.5Zn0.5Fe2O4/SiO2 nanocomposites by auto-combustion. The obtained (Ni0.5Zn0.5Fe2O4)100-x(SiO2)x (x=5,10,20wt%) samples were characterized by IR, DTA-TG, 29Si CP/MAS NMR and XRD techniques. The nitrate-citrate-silica gels exhibited self-propagating combustion behavior, and it directly transformed into nanosized (8-16nm) NiZn ferrite particles with spinel crystal structure after combustion. The content of silica in the starting solution affects the combustion process, and then determines the particle size of the as-synthesized powder. The interaction between NiZn ferrite and silica was investigated through the 29Si CP/MAS NMR spectra. It was found that a change of chemical shift and band intensity occurs in the Q3 and Q4 resonance.

Wu, Kuo Hui; Chang, Yin Chiung; Wang, Gaw Pying

2004-02-01

211

Preparation and characterization of magnetic nanoparticles with controlled magnetization  

Microsoft Academic Search

The effect of molar ratio of two hydrated iron salts used as precursors into a (co)precipitation-based synthesis method, on\\u000a the composition, size and specific saturation magnetization of mixed iron oxides and oxyhydroxides magnetic nanoparticles\\u000a as reaction products, was studied. The preparation procedure is based on a salt-assisted solid-state chemical reaction. The\\u000a obtained products are magnetic multiphase components with the mean

Dumitru-Daniel Herea; Horia Chiriac; Nicoleta Lupu

212

Preparation and characterization of hyaluronic acid-based hydrogel nanoparticles  

Microsoft Academic Search

Novel polymeric amphiphilic hydrogel nanoparticles have been prepared by covalent attachment of hydrophobic tetradecylamine (TDA) to hyaluronic acid (HA) in the presence of 1-ethyl-3(3-dimethylaminopropyl)carbodiimide and N-hydroxysulfosuccinimide. Their chemical structure and self-association behavior in an aqueous solution were investigated by using 1H NMR, dynamic light scattering, fluorescence spectroscopy, and transmission electron microscopy (TEM). Owing to their amphiphilic characteristics, the resulting conjugates

Ki Young Choi; Seulki Lee; Kwangmeyung Kim; Jae Hyung Park; Ick Chan Kwon; Seo Young Jeong

2008-01-01

213

A supramolecular approach for preparation of size-controlled nanoparticles.  

PubMed

A supramolecular approach has been developed for the preparation of supramolecular nanoparticles (SNPs) with variable sizes (30-450 nm) from three different molecular building blocks using a cyclodextrin/adamantane recognition system. Positron emission tomography (PET) was employed to study the biodistribution and lymph node drainage of the SNPs in mice. The sizes of the SNPs affect their in vivo characteristics (see picture). PMID:19425037

Wang, Hao; Wang, Shutao; Su, Helen; Chen, Kuan-Ju; Armijo, Amanda Lee; Lin, Wei-Yu; Wang, Yanju; Sun, Jing; Kamei, Ken-ichiro; Czernin, Johannes; Radu, Caius G; Tseng, Hsian-Rong

2009-01-01

214

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

NASA Astrophysics Data System (ADS)

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.

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

2012-11-01

215

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

PubMed

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

Akbarzadeh, Abolfazl; Samiei, Mohamad; Davaran, Soodabeh

2012-02-21

216

Synthesis of epoxy ferrite nanocomposites in supercritical carbon dioxide  

Microsoft Academic Search

A series of epoxy ferrite nanocomposites (EFNCs) was synthesised through dispersing ferrite nanoparticles (5.0 phr, parts per hundred of resin) into diglycidylether of bisphenol A (0.1 mol) in supercritical carbon dioxide at 85 ± 1°C, 1600 psi over 1 h followed by curing with triethylene tetramine (15 phr) at 40 ± 1°C. For this purpose, ferrite nanoparticles were synthesised through

M. G. H. Zaidi; P. L. Sah; S. Alam; A. K. Rai

2009-01-01

217

Magnetic characterization of nanocrystalline Ni-Zn ferrite powder prepared by the glyoxylate precursor method  

Microsoft Academic Search

Nanocrystalline Ni0.35Zn0.65Fe2O4 mixed ferrite was obtained from the Fe2(Ni0.35,Zn0.65)(OH)4(C2H2O4)2cH2O complex combination that corresponds to the atomic ratio Ni(II) : Zn(II) : Fe(III) = 0.35 : 0.65 : 2 the complex combination was decomposed at 325°C and the resulting oxides mixture was annealed in the temperature range of 400-1000°C for 2 h. The thermal analysis of the synthesized complex combination was

C. Caizer; M. Stefanescu

2002-01-01

218

Electrophoretic preparation and characterization of porous electrodes from diamond nanoparticles  

NASA Astrophysics Data System (ADS)

We carried out chemical purification of commercially available diamond nanoparticles by refluxing in aqueous HNO3 and characterized the samples by spectroscopic and surface techniques before and after purification. As a first step in the preparation of electrodes for electrochemistry, we have electrophoretically deposited thin, highly uniform films of controlled thickness (1-8 ?m) on silicon substrates using the purified diamond nanoparticles. These have been characterized by scanning electron microscopy (SEM). All films obtained were homogeneous in thickness and without macroscopic holes or cracks. Such structures could also be used in many other applications such as fuel cells or lithium batteries. We have performed cyclic voltammetry experiments with these electrodes. The voltammograms of diamond nanoparticles electrophoretically deposited on silicon indicate hydrogen evolution. This demonstrates that the material is useful as electrocatalitic support. This conclusion is supported by the cyclic voltammograms obtained using ferrycyanide (III) chloride and hexaamineruthenium (III) chloride complexes as redox probes. However, these redox probes showed very small peak currents. This behavior could be improved by doping the diamond nanoparticles with an impurity such as boron.

La Torre Riveros, Lyda; Soto, Keyla; Tryk, Donald A.; Cabrera, Carlos R.

2007-04-01

219

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

NASA Astrophysics Data System (ADS)

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

Wang, Yan; Huang, Ying; Wang, Qiufen

2012-09-01

220

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

Microsoft Academic Search

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

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

1992-01-01

221

Preparation and properties of superparamagnetic nanoparticles with narrow size distribution and biocompatible  

Microsoft Academic Search

A chemical co-precipitation method capable of controlling the average size and size distribution of magnetic Fe3O4 nano-particles was developed. It was found that the homogeneous variation of the pH value in the solution plays a role in the size distribution of the synthesized Fe3O4 particles. In this work, we added urea to the ferrite solution, followed by heating the solution

Wanquan Jiang; H. C. Yang; S. Y. Yang; H. E. Horng; J. C. Hung; Y. C. Chen; Chin-Yih Hong

2004-01-01

222

Preparation and characterization of magnetic nanoparticles coated with polyethylene glycol  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

223

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

Microsoft Academic Search

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

Hideki Murakami; Masao Kobayashi; Hirofumi Takeuchi; Yoshiaki Kawashima

1999-01-01

224

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

PubMed

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

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

2010-06-09

225

Preparation and characterization of Pd{sub 2}Sn nanoparticles  

SciTech Connect

We report a non-aqueous solution preparation of Pd{sub 2}Sn nanoparticles with sizes near 20 nm. The intermetallic compound with the Co{sub 2}Si structure has been characterized using transmission electron microscopy, Rietveld refinement of synchrotron X-ray and neutron powder diffraction, and real-space pair distribution function analysis of high-energy synchrotron X-ray scattering. We also present a description of the electronic structure of this covalent intermetallic using density functional calculations of the electronic structure.

Page, Katharine [Materials Department and Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Schade, Christina S. [Materials Department and Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitaet Mainz, Duesbergweg 10-14, Mainz D55099 (Germany); Zhang, Jinping [Materials Department and Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Chupas, Peter J.; Chapman, Karena W. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Proffen, Thomas [Los Alamos National Laboratory, Lujan Neutron Scattering Center LANSCE-12, MS H805, Los Alamos, NM 87545 (United States); Cheetham, Anthony K. [Materials Department and Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Seshadri, Ram [Materials Department and Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States)], E-mail: seshadri@mrl.ucsb.edu

2007-12-04

226

Surface Functionalized Water-Dispersible Magnetite Nanoparticles: Preparation, Characterization and the Studies of Their Bioapplications  

Microsoft Academic Search

Iron oxide magnetic nanoparticle synthesis and their surface functionalization hold a crucial position in the design and fabrication of functional materials for a variety of biomedical applications. Non-uniform nanoparticles with poor crystallinity, prepared by conventional methods, have only limited value in biological areas. Large scale synthesis methods that are able to produce high quality, mono-dispersed iron oxide nanoparticles using low

Haiou Qu

2012-01-01

227

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

228

Pullulan acetate coated magnetite nanoparticles for hyperthermia: Preparation, characterization and in vitro experiments  

Microsoft Academic Search

Amphipathic polymer pullulan acetate (PA)-coated magnetic nanoparticles were prepared and characterized by various physicochemical\\u000a means. The cytotoxicity and cellular uptake of the magnetic nanoparticles were examined. The hyperthermic effect of the magnetic\\u000a nanoparticles on tumor cells was evaluated. Transmission electron microscopy (TEM) showed that the PA coated magnetic nanoparticles\\u000a (PAMNs) had spherical morphology. Dynamic light scattering (DLS) showed that the

Fuping Gao; Yuanyuan Cai; Jing Zhou; Xiaoxue Xie; Weiwei Ouyang; Yuhui Zhang; Xufei Wang; Xiaodong Zhang; Xiaowen Wang; Lingyun Zhao; Jintian Tang

2010-01-01

229

Preparation, cellular internalization, and biocompatibility of highly fluorescent PMMA nanoparticles.  

PubMed

Methacrylate monomers were functionalized with a 4-hydroxythiazole chromophore and copolymerized with methyl methacrylate via RAFT. Nanoparticles of 120 and 500 nm in size were prepared without using stabilizers/surfactants. For comparative studies, preparative ultracentrifugation was applied for the separation into small and large particle fractions. All suspensions were characterized by DLS, AUC, and SEM and tested regarding their stability during centrifugation and re-suspension, autoclavation, and incubation in cell culture media. In vitro studies with mouse fibroblast cell line and differently sized NP showed a particle uptake into cells. Biocompatibility, non-toxicity, and hemocompatibility were demonstrated using a XTT assay, a live/dead staining, and an erythrocyte aggregation and hemolysis assay. PMID:22887637

Vollrath, Antje; Pretzel, David; Pietsch, Christian; Perevyazko, Igor; Schubert, Stephanie; Pavlov, George M; Schubert, Ulrich S

2012-08-07

230

Microstructural characterization of Ni nanoparticles prepared by anodic arc plasma  

SciTech Connect

The particle size, specific surface area, crystal structure and morphology of Ni nanoparticles prepared by an anodic arc discharge plasma method were characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED), X-ray energy dispersive spectrometry (XEDS), the Brunauer-Emmett-Teller (BET) equation, and the Barrett-Joyner-Halenda (BJH) method. The experimental results indicate that the crystal structure of the samples is face centered cubic (FCC) the same as that of the bulk materials, the specific surface area is 14.23 m{sup 2}/g, with the particle size distribution ranging from 20 to 70 nm, the cumulative volume of the pores is 0.09 cm{sup 3}/g, the average pore diameter is 23 nm, and the average particle size about 47 nm. The grain size D {sub XRD} is smaller than the particle size D {sub TEM} and D {sub BET} due to agglomeration. The nanoparticles prepared by this method achieved uniform size, low impurity contamination, narrow size distribution and spherical shape.

Wei Zhiqiang [School of Sciences, Lanzhou Univ. of Tech., Lanzhou, 730050 (China) and State Key Lab. of Advanced New Non-ferrous Materials, Lanzhou Univ. of Tech., Lanzhou 730050 (China)]. E-mail: zqwei7411@163.com; Yan Pengxun [Institute of Plasma and Metal Materials, Lanzhou University, Lanzhou, 730000 (China); Feng Wangjun [School of Sciences, Lanzhou Univ. of Tech., Lanzhou, 730050 (China); Dai Jianfeng [School of Sciences, Lanzhou Univ. of Tech., Lanzhou, 730050 (China); Wang Qing [School of Sciences, Lanzhou Univ. of Tech., Lanzhou, 730050 (China); Xia Tiandong [State Key Lab. of Advanced New Non-ferrous Materials, Lanzhou Univ. of Tech., Lanzhou 730050 (China)

2006-09-15

231

Preparation of some metal ferrite MFe 2O 4 thin films through a nonaqueous sol method  

Microsoft Academic Search

Fe2O3, CoFe2O4, CuFe2O4, MnFe2O4 and NiFe2O4 films were prepared by a nonaqueous sol method. The sols were prepared by dissolving 10% by weight of the corresponding nitrates in ethylene glycol and heating the solution at 85 °C under nitrogen. Fe2O4 films were prepared by reducing the initial Fe2O3 films in H2Ar (1090).

Yunchang Zhang

1995-01-01

232

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

PubMed Central

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

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

2013-01-01

233

Preparation and properties of bio-compatible magnetic Fe3O4 nanoparticles  

Microsoft Academic Search

In this work, we study the preparation and properties of bio-compatible magnetic nanoparticles for immunoassay and DNA detection. The magnetite (Fe3O4) nanoparticles were prepared by a chemical co-precipitation method and dextran was selected as the surfactant to suspend the nanoparticles. Suspended particles associated with avidin followed by biotin were qualitatively analyzed by enzyme-linked immunosorbent assay (ELISA) method. We found further

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

2006-01-01

234

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

Microsoft Academic Search

In this work, we study the preparation and properties of bio-compatible magnetic nanoparticles for immunoassay and DNA detection. The magnetite (Fe3O4) nanoparticles were prepared by a chemical co-precipitation method and dextran was selected as the surfactant to suspend the nanoparticles. Suspended particles associated with avidin followed by biotin were qualitatively analyzed by enzyme-linked immunosorbent assay (ELISA) method. We found further

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

2006-01-01

235

Preparation and magnetic properties of iron oxide and carbide nanoparticles in carbon nanotube matrix  

Microsoft Academic Search

The present work describes a procedure for the preparation of iron oxide and carbide nanoparticles in carbon nanotube (CNT) matrix using the wet impregnation method and subsequent heat treatment in different atmosphere. In this way, two specific composites were produced with magnetite and cementite phase particles dispersed in CNTs, respectively, and cementite particles were encapsulated in graphene shells. As-prepared nanoparticles

J. P. Cheng; X. B. Zhang; G. F. Yi; Y. Ye; M. S. Xia

2008-01-01

236

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

PubMed

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

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

2010-12-08

237

Preparation and characterization of solid lipid nanoparticles loaded with doxorubicin.  

PubMed

Solid lipid nanoparticles (SLN) loaded with doxorubicin were prepared by solvent emulsification-diffusion method. Glyceryl caprate (Capmul)MCM C10) was used as lipid core, and curdlan as the shell material. Dimethyl sulfoxide (DMSO) was used to dissolve both lipid and drug. Polyethylene glycol 660 hydroxystearate (Solutol)HS15) was employed as surfactant. Major formulation parameters were optimized to obtain high quality nanoparticles. The mean particle size measured by photon correlation spectroscopy (PCS) was 199nm. The entrapment efficiency (EE) and drug loading capacity (DL), determined with fluorescence spectroscopy, were 67.5+/-2.4% and 2.8+/-0.1%, respectively. The drug release behavior was studied by in vitro method. Cell viability assay showed that properties of SLN remain unchanged during the process of freeze-drying. Stability study revealed that lyophilized SLN were equally effective (p<0.05) after 1 year of storage at 4 degrees C. In conclusion, SLN with small particle size, high EE, and relatively high DL for doxorubicin can be obtained by this method. PMID:19406231

Subedi, Robhash Kusam; Kang, Keon Wook; Choi, Hoo-Kyun

2009-05-03

238

Preparation, characteristics, and stability of glutathione-loaded nanoparticles.  

PubMed

The aim of this study was to investigate the characteristics and oxidative stability of chitosan-glutathione conjugate (CS-GSH) and CS-GSH nanoparticles (CS-GSH NPs) to explore the potentials of these nanoparticle systems for GSH delivery. CS-GSH was synthesized using a radical polymerization method, and CS-GSH NP was prepared by ionic gelation of CS-GSH with sodium tripolyphosphate (TPP). The sizes of CS-GSH NPs significantly increased with increasing CS-GSH concentration and CS-GSH/TPP ratio. The entrapment efficiency (EE) significantly increased with increasing CS-GSH concentration and significantly decreased with increasing CS-GSH/TPP ratio. The immobilized GSH could be protected against oxidation compared to free GSH. The thiol content in the nanoencapsulated GSH was more effectively maintained than those in free GSH and CS-GSH, regardless of the presence of oxidative stress-inducing agents. These results suggest that CS-GSH NP can be used to enhance the oxidative stability of GSH. PMID:21888356

Koo, Seung Hyun; Lee, Ji-Soo; Kim, Gun-Hee; Lee, Hyeon Gyu

2011-09-28

239

Preparation and characterization of spironolactone nanoparticles by antisolvent precipitation.  

PubMed

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

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

2009-03-24

240

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

241

Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.  

PubMed

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

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

2012-05-01

242

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

NASA Astrophysics Data System (ADS)

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.

Bian, Longchun; Bao, Lixia; Wang, Jiliang; Lei, Jingxin

2013-07-01

243

Sonochemical Preparation of Monometallic, Bimetallic and Metal-Loaded Semiconductor Nanoparticles  

NASA Astrophysics Data System (ADS)

A convenient method to synthesize metal nanoparticles with unique properties is highly desirable for many applications. The sonochemical reduction of metal ions has been found to be useful for synthesizing nanoparticles of desired size range. In addition, bimetallic alloys or particles with core-shell morphology can also be synthesized depending upon the experimental conditions used during the sonochemical preparation process. The photocatalytic efficiency of semiconductor particles can be improved by simultaneous reduction and loading of metal nanoparticles on the surface of semiconductor particles. The current review focuses on the recent developments in the sonochemical synthesis of monometallic and bimetallic metal nanoparticles and metal-loaded semiconductor nanoparticles.

Anandan, Sambandam; Ashokkumar, Muthupandian

244

Preparation and Evaluation of Montelukast Sodium Loaded Solid Lipid Nanoparticles  

PubMed Central

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.

Priyanka, K; Sathali, A Abdul Hasan

2012-01-01

245

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

PubMed Central

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

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

2011-01-01

246

Preparation, characterization and antibacterial properties against E. coli K88 of chitosan nanoparticle loaded copper ions  

NASA Astrophysics Data System (ADS)

The present study was conducted to prepare and characterize chitosan nanoparticle loaded copper ions, and evaluate their antibacterial activity. Chitosan nanoparticles were prepared based on ionotropic gelation, and then the copper ions were loaded. The particle size, zeta potential and morphology were determined. Antibacterial activity was evaluated against E. coli K88 by determination of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in vitro. Results showed that the antibacterial activity was significantly enhanced by the loading of copper ions compared to those of chitosan nanoparticles and copper ions. The MIC and MBC of chitosan nanoparticle loaded copper ions were 21 times and 42 times lower than those of copper ions, respectively. To confirm the antibacterial mechanism, morphological changes of E. coli K88 treated by chitosan nanoparticle loaded copper ions were dynamically observed with an atomic force microscope (AFM). It was found that chitosan nanoparticle loaded copper ions killed E. coli K88 through damage to the cell membrane.

Du, Wen-Li; Xu, Ying-Lei; Xu, Zi-Rong; Fan, Cheng-Li

2008-02-01

247

Polymer?Nanoparticle Composites: Preparative Methods and Electronically Active Materials  

Microsoft Academic Search

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

P. K. Sudeep; Todd Emrick

2007-01-01

248

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

Microsoft Academic Search

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

Sabar D. Hutagalung; Siaw C. Loo

2007-01-01

249

Preparation and antibacterial activity of Fe3O4@Ag nanoparticles  

Microsoft Academic Search

Bifunctional Fe3O4@Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are

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

2007-01-01

250

Preparation and characterization of self-assemblied nanoparticles based on folic acid modified carboxymethyl chitosan  

Microsoft Academic Search

Folate (FA) modified carboxymethyl chitosan (FCC) has been synthesized and the hydrogel nanoparticles can be prepared after\\u000a the sonication. Formation and characteristics of nanoparticles of FCC were studied by fluorescence spectroscopy and dynamic\\u000a light scattering methods. The critical aggregation concentration value of FCC in water was 9.34 × 10?2 mg\\/ml and the mean hydrodynamic diameter of particle was 267.8 nm. The morphology of nanoparticles

Yu-long Tan; Chen-Guang Liu

2011-01-01

251

Encapsulation of BSA in polylactic acid–hyperbranched polyglycerol conjugate nanoparticles: preparation, characterization, and release kinetics  

Microsoft Academic Search

Nanoparticles based on an amphiphilic copolymer with polylactic acid (PLA) grafted onto hyperbranched polyglycerol (HPG) were\\u000a prepared by the use of BSA as a model protein. The characteristics of the nanoparticles were evaluated using particle size\\u000a analyzer, transmission electron microscopy, and X-ray photoelectron spectroscopy. The secondary structure of BSA released\\u000a from nanoparticles were analysed by circular dichroism experiments. Cell viability

Xiujun Gao; Xinge Zhang; Xuejiao Zhang; Cui Cheng; Zhen Wang; Chaoxing Li

2010-01-01

252

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

PubMed Central

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

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

2012-01-01

253

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

PubMed

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

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

2012-04-11

254

Preparation and passive target of 5-fluorouracil solid lipid nanoparticles.  

PubMed

This work studied the intravenous injection formulation of solid lipid nanoparticles (SLNs) loaded with 5-fluorouracil (5-FU). The goal was to design longer drug residence in vivo and passive targeting nanoparticles which could improve therapeutic efficacy and reduce side-effects. Based on the optimized results of uniform design experiment, 5-FU-SLNs were prepared by multiple emulsion-ultrasonication (w/o/w). The SLNs were found to be relatively uniform in size (182.1 +/- 25.8 nm) with a negative zeta potential (-27.89 +/- 5.1 mV). The average drug entrapment efficiency and loading were 74% and 10%, respectively. Compared with the 5-FU solution (t(1/2beta), 0.593h; MRT, 0.358h) after intravenous injection to rats, the pharmacokinetic parameters of 5-FU-SLNs exhibited a longer retention time. (t(1/2beta), 4.0628h; MRT, 3.5321h). The area under curve of plasma concentration-time (AUC) of 5-FU-SLNs was 1.48 times greater than that of free drugs. The overall targeting efficiency (TE(C)) of the 5-FU-SLNs was enhanced from 13.25-20.45% in the lung and from 11.48-23.16% in kidney while the spleen distribution of 5-FU was significantly reduced as compared with that of the 5-FU solution. These results indicated that 5-FU-SLNs were promising passive targeting therapeutic agents for curing primary lung carcinoma. PMID:19769532

Du, Bin; Yan, Ying; Li, Ying; Wang, Shuyu; Zhang, ZhenZhong

255

Investigation of antibacterial properties silver nanoparticles prepared via green method  

PubMed Central

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

2012-01-01

256

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

NASA Astrophysics Data System (ADS)

Thin films of Ba2Zn2Fe12O22 (Y) hexaferrite were prepared through the chemical solution deposition method on SrTiO3(1 1 1) (ST) single crystal substrates using epitaxial SrFe12O19 (M) hexaferrite thin layer as a seed template layer. The process of crystallization was mainly investigated by means of X-ray diffraction and atomic force microscopy. A detailed inspection revealed that growth of seed layer starts through the break-up of initially continuous film into isolated grains with expressive shape anisotropy and hexagonal habit. The vital parameters of the seed layer, i.e. thickness, substrate coverage, crystallization conditions and temperature ramp were optimized with the aim to obtain epitaxially crystallized Y phase. X-ray diffraction Pole figure measurements and ? scans reveal perfect parallel in-plane alignment of SrTiO3 substrate and both hexaferrite phases.

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

2013-07-01

257

Synthesis and Optical Properties of Sulfide Nanoparticles Prepared in Dimethylsulfoxide  

SciTech Connect

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

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

2008-11-01

258

Superparamagnetic iron oxide nanoparticles prepared by using an improved polyol method  

NASA Astrophysics Data System (ADS)

Superparamagnetic iron oxide nanoparticles were synthesized by thermal decomposition of iron (III) acetylacetonate (Fe(acac)3) in PEG containing poly(vinyl pyrrolidone) (PVP) or poly(ethylene imine) (PEI). The morphologies and phase compositions of the nanoparticles were determined by transmission electron microscopy and X-ray diffraction, respectively. The surface coating of the nanoparticles was recognized using Fourier transform infrared spectroscopy and the presence of the surface coating was confirmed by Thermogravimetric analyses. Magnetic properties were measured using superconducting quantum interference device. The zeta potentials and hydrodynamic sizes of the nanoparticles were determined using nano-particle and zeta potential analyzer. The superparamagnetic iron oxide nanoparticles with sizes from 4.1 nm to 14.9 nm were prepared in the present work, which could be tuned by varying factors such as the reaction temperature, the reaction time, and the PVP or PEI contents. The superparamagnetic nanoparticles were jointly coated with PEG/PVP or PEG/PEI. With hydrodynamic sizes smaller than 40 nm and neutral or positive zeta potentials these superparamagnetic iron oxide nanoparticles exhibited higher dispersion stability in deionized water and in phosphate buffered saline as compared with the superparamagnetic iron oxide nanoparticles coated with PEG alone. This work demonstrates that superparamagnetic iron oxide nanoparticles with modulated properties can be prepared simply by using the improved polyol method.

Zhang, Baolin; Tu, Zhijiang; Zhao, Fangyuan; Wang, Jun

2013-02-01

259

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

PubMed

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

Abu Tarboush, Belal J; Husein, Maen M

2012-04-19

260

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

National Technical Information Service (NTIS)

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 as protective agents. The sizes of the nanoparticles can be systematically varied f...

J. Liu Y. Li Y. Wang Z. L. Wang

2001-01-01

261

Nanoaggregates of a pentacenequinone derivative as reactors for the preparation of palladium nanoparticles.  

PubMed

Fluorescent nanoaggregates of pentacenequinone derivative serve as reactors for the preparation of palladium nanoparticles in aqueous medium. Further, the combination of catalytic quantities of palladium nanoparticles with NaBH(4) smoothly reduces 4-nitrophenol to 4-aminophenol in aqueous medium. PMID:23042509

Bhalla, Vandana; Gupta, Ankush; Kumar, Manoj

2012-12-18

262

The preparation and characterization of folate-conjugated human serum albumin magnetic cisplatin nanoparticles  

Microsoft Academic Search

ObjectiveNanoparticles are becoming an important method of targeted drug delivery. To evaluate the importance of folate-conjugated human serum albumin (HSA) magnetic nanoparticles (Folate-CDDP\\/HSA MNP), we prepared drug-loaded Folate-CDDP\\/HSA MNPs and characterized their features.

Daozhen Chen; Qiusha Tang; Wenqun Xue; Jingying Xiang; Li Zhang; Xinru Wang

2010-01-01

263

Novel phase-transfer preparation of monodisperse silver and gold nanoparticles at room temperature  

Microsoft Academic Search

In a novel water-cyclohexane two-phase system, the aqueous formaldehyde is transferred to cyclohexane phase via reaction with dodecylamine to form reductive intermediates in cyclohexane; the intermediates are capable of reducing silver or gold ions in aqueous solution to form dodecylamine protected silver and gold nanoparticles in cyclohexane solution at room temperature. The prepared silver and gold nanoparticles are examined by

Yangying Chen; Xinkui Wang

2008-01-01

264

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

PubMed

The adsorption characteristics of BSA onto the magnetic chitosan nanoparticles have been investigated in this paper. The magnetic chitosan nanoparticles were prepared by adding the basic precipitant of NaOH solution into a W/O microemulsion system. The morphology of magnetic chitosan nanoparticles was observed by transmission electron microscope (TEM). It was found that the diameter of magnetic chitosan nanoparticles was from 10nm to 20 nm, and the nanoparticles suspending in the aqueous solution could easily aggregate by a magnet, which suggested that the nanoparticles had good magnetic characteristics. The BSA adsorption experiment indicated that when pH of BSA solution was equal to 4, the maximum adsorption loading reached 110 mg/g. Through measuring the zeta potential of BSA solution and the magnetic nanoparticles, it was found that under this situation the surface of BSA took the negative charge, but the magnetic nanoparticles took the positive charge. Due to the small diameter, the adsorption equilibrium of BSA onto the nanoparticles reached very quickly within 10 min. The adsorption equilibrium of BSA onto the magnetic chitosan nanoparticles fitted well with the Freundlich model. The experimental results showed that the magnetic chitosan nanoparticles have potential to be used for the quick pretreatment in the protein analysis process. PMID:17892932

Wang, Yujun; Wang, Xianghua; Luo, Guangsheng; Dai, Youyuan

2007-09-24

265

Gas sensing properties of ZnFe2O4 nanoparticles  

NASA Astrophysics Data System (ADS)

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

Misra, Susmita; Ram, S.

2013-06-01

266

Preparation and properties of new potassium-barium ferrite with mixed beta-alumina and magnetoplumbite structure  

Microsoft Academic Search

A new hexaferrite (ideal composition: KBaFe23O36) with mixed beta-alumina and magnetoplumbite structure was synthesized by the solid-state reaction of the mixture 0.45K2CO3 . 0.55BaCO3 . 6Fe2O3 at 1300 to 1350°C. The alternate stacking structure of half cells of K+-beta-ferrite and Ba hexaferrite was proposed based on the X-ray powder diffraction pattern of this ferrite. A similar compound was also found

Shinya Nariki; Shigeru Ito; Noboru Yoneda

1990-01-01

267

Preparation and characterization of novel coenzyme Q 10 nanoparticles engineered from microemulsion precursors  

Microsoft Academic Search

The purpose of these studies was to prepare and characterize nanoparticles into which Coenzyme Q10 (CoQ10) had been incorporated (CoQ10-NPs) using a simple and potentially scalable method. CoQ10-NPs were prepared by cooling warm microemulsion precursors composed of emulsifying wax, CoQ10, Brij 78, and\\/or Tween 20. The nanoparticles were lyophilized, and the stability of CoQ10-NPs in both lyophilized form and aqueous

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

2003-01-01

268

Facile preparation of ordered mesoporous silica-carbon composite nanoparticles for glycan enrichment.  

PubMed

Silica-carbon composite nanoparticles (NP-MCM-C) with uniform shapes and highly ordered mesoporous structures are directly prepared by using template polymers as the carbon source. And, taking advantage of the size exclusion effect of the mesopores to proteins and the specific interaction between carbon and oligosaccharides, the prepared nanoparticles are utilized to enrich N-linked glycans from complex biological samples with high selectivity and efficiency. PMID:23628764

Qin, Hongqiang; Hu, Zhengyan; Wang, Fangjun; Zhang, Yi; Zhao, Liang; Xu, Guiju; Wu, Ren'an; Zou, Hanfa

2013-06-01

269

Optimization of Preparation Techniques for Poly(Lactic Acid-Co-Glycolic Acid) Nanoparticles  

Microsoft Academic Search

Microparticles and nanoparticles of poly(lactic acid-co-glycolic acid) (PLAGA) are excellent candidates for the controlled release of many pharmaceutical compounds because of their biodegradable nature. The preparation of submicron PLAGA particles poses serious challenges that are not necessarily present when preparing microparticles. We have evaluated several combinations of organic solvents and surfactants used in the formulation of PLAGA nanoparticles. Critical factors

Duane T. Birnbaum; Jacqueline D. Kosmala; Lisa Brannon-Peppas

2000-01-01

270

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

Microsoft Academic Search

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

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

2008-01-01

271

Preparation and magnetic properties of fibrous gamma iron oxide nanoparticles via a nonaqueous medium  

Microsoft Academic Search

Fibrous shape ?-Fe2O3 nanoparticles (the length of ?850 nm; the width of ?5 nm) have been prepared using lauryl alcohol as a nonaqueous medium. The resultant products were investigated by IR, TG–DTA, XRD, TEM and magnetization measurements. For the preparation of pure ?-Fe2O3 nanoparticles, the suitable condition of the molar ratio of lauryl alcohol to iron nitrate is determined to

Zhihong Jing

2006-01-01

272

Preparation of near-infrared light absorbing gold nanoparticles using polyethylene glycol-attached dendrimers  

Microsoft Academic Search

The photochemical properties of gold nanoparticles (Au NPs) are largely influenced by their size and morphology. Stably dispersed Au NPs that absorb near-infrared (NIR) light are useful for biomedical applications. We prepared well-dispersed NIR-absorbing Au NPs using seeding growth from Au NPs encapsulated in polyethylene glycol (PEG)-attached dendrimers. Formaldehyde was used as a reductant to prepare gold nanoparticles with convex–concave

Chie Kojima; Yasuhito Umeda; Atsushi Harada; Kenji Kono

2010-01-01

273

Sonolytical preparation of various types of metal nanoparticles in aqueous solution  

Microsoft Academic Search

Composite nanoparticles of Au, Pd and Pt, and nanoparticles of transition metal oxides, MnO2, were prepared by the sonochemical reduction of corresponding ions (Au(III), Pd(II), Pt(II), Pt(IV) and Mn(VII)) in an aqueous system in the presence of surfactants. The prepared noble metal particles were stable and the sizes were of the order of nanometer with narrow distribution. Surfactants were found

Taku Fujimoto; Yoshiteru Mizukoshi; Yoshio Nagata; Yasuaki Maeda; Ryuichiro Oshima

2001-01-01

274

Preparation and characterisation of rose Bengal-loaded surface-modified albumin nanoparticles  

Microsoft Academic Search

Surface-modified albumin nanoparticles were prepared from two poly(ethylene glycol)–human serum albumin conjugates: poly(thioetheramido acid)–poly(ethylene glycol) copolymer-grafted HSA (HSA–PTAAC–PEG) and methoxy poly(ethylene glycol)-grafted HSA (HSA–mPEG). Rose bengal (RB) was used as a model drug for encapsulation into the nanoparticles either during the particle production or by adsorption post particle preparation. The drug incorporation and release was affected by the different production

Wu Lin; Martin C. Garnett; Stanley S. Davis; Etienne Schacht; Paulo Ferruti; Lisbeth Illum

2001-01-01

275

The preparation and characterization of nanoparticle TiO 2\\/Ti films and their photocatalytic activity  

Microsoft Academic Search

Nanoparticle TiO2\\/Ti films were prepared by a sol–gel process using Ti(OBu)4 as raw material, the as-prepared film samples were also characterized by TG-DTA, XRD, TEM, SEM, XPS, DRS, PL, SPS and EFISPS testing techniques. TiO2 nanoparticles experienced two processes of phase transition, i.e. amorphous to anatase and anatase to rutile at the calcining temperature range from 450 to 700°C. TiO2

Jing Liqiang; Sun Xiaojun; Cai Weimin; X. Zili; D. Yaoguo; F. Honggang

2003-01-01

276

Preparation of gold nanoparticle aggregates and their photothermal heating property.  

PubMed

This report describes simple synthetic strategies to prepare partially aggregated gold nanoparticles (GNPs) and their ability to produce photothermally-induced heating of an aqueous medium upon exposure to broadband light. The formation of various GNPs and their aggregates were accomplished in the absence of surfactants at room temperature. The morphologies, structures, and absorption properties of these GNPs were carefully characterized. Given that the resulting GNPs possessing strong and wide absorption bands fall in the most intense solar radiation spectrum, the photothermally-induced heating of water was examined in the presence of the GNPs via irradiation with a solar simulator (i.e., 100 mW/cm2; 1-sun condition). Our GNPs exhibited a slightly greater increase in the water temperature (3-4 degrees C) than that of conventional citrate-stabilized GNPs. This superior photothermal heating property of our GNPs directly indicated that the intense and broad absorption band effectively improved the conversion of highly absorbed photon energy into heat. PMID:21446405

Kim, Jun-Hyun; Lavin, Brian W

2011-01-01

277

Preparation and characterization of fluorescent silica coated magnetic hybrid nanoparticles  

Microsoft Academic Search

In this report we describe the synthesis, characterization of fluorescent silica coated magnetic hybrid nanoparticles. These nanoparticles have been synthesized by combining the co-precipitation, polymerization and sol–gel technology with fluorescent dye. And their size can range from about 80 to 90nm in diameter. The nanoparticles were characterized by atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy, spectrofluorometer, X-ray diffraction

Kaliyaperumal Viswanathan

2011-01-01

278

Preparation of magnetic nanoparticles by pulsed plasma chemical vapor synthesis  

Microsoft Academic Search

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

I. Matsui

2006-01-01

279

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

SciTech Connect

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

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

2009-12-15

280

[Preparation of superparamagnetic paclitaxel nanoparticles from modified chitosan and their cytotoxicity against malignant brain glioma].  

PubMed

We synthesized the superparamagnetic paclitaxel nanoparticles from modified chitosan tangling around Fe3O4 ferrofluid and taxol, and observed the nanoparticles with transmission electronic microscopy (TEM). Then we evaluated the paramagnetism of the particles by vibration specimen magnetometer (VSM) and tested their cytotoxicity with flow cytometry (FCM). The prepared nanoparticle solution was black without any floccule or sediment and appeared transparent after diluted. The nanoparticles were spherical and dispersed in water with mean diameter of 15 nm under TEM and showed superparamagnetic character. FCM test showed the nanoparticles had significant toxic effects against malignant astrocytoma U251 cell lines, equal to taxol alone. These results showed that the superparamagnetic nanoparticle not only enhanced the solubility of paclitaxel in water, but also was superparamagnetic and cytotoxic, which make suitable tools for magnetic targeting chemotherapy of brain gliomas. PMID:21774213

Zhao, Ming; Li, Anmin; Chang, Jin; Wang, Hanjie; Liang, Shuli; Zhang, Jiajing; Yan, Runmin

2011-06-01

281

Preparation and optical properties of composite thin films with embedded InP nanoparticles  

Microsoft Academic Search

InP nanoparticles embedded in SiO2 thin films were prepared by radio-frequency magnetron co-sputtering. We analyzed the structure and growth behavior of the\\u000a composite films under different preparation conditions. X-ray diffraction and Raman spectroscopy analyses indicate that InP\\u000a nanoparticles have a polycrystalline structure. The average size of InP nanoparticles is in the range of 3–10 nm. The broadening\\u000a and red shift

Maojun Zheng; Lide Zhang; Guanghai Li; Zhi Jiang

2001-01-01

282

A novel method for the preparation of silver chloride nanoparticles starting from their solid powder using microemulsions  

Microsoft Academic Search

A novel method of preparing AgCl nanoparticles by mixing AgCl powder and a microemulsion consisting of dioctyldimethylammonium chloride\\/n-decanol\\/water\\/isooctane is introduced. This new method was discovered during the preparation of AgCl nanoparticles in single microemulsions by direct reaction with the dioctyldimethylammonium chloride surfactant counterion. The effect of the following variables on the concentration of the colloidal AgCl nanoparticles (the nanoparticle uptake)

Maen M. Husein; Eva Rodil; Juan H. Vera

2005-01-01

283

Magnetic nanoparticle properties and microstructure formation in liquid dispersions  

Microsoft Academic Search

The physical properties and microstructures of magnetite and cobalt ferrite nanoparticles, dispersed in liquid matrices, are studied. Qualitative and quantitative analyses of static magnetization curves were performed. Magneto-granulometric results were obtained and interactions and agglomerations were evidenced, as a function of the preparation techniques as well as carrier liquids and surfactants used

L. V. M. Rasa; D. Bica

2000-01-01

284

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

NASA Astrophysics Data System (ADS)

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

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

2009-10-01

285

Synthesis and characterization of CoFe2O4 magnetic nanoparticles prepared by temperature-controlled coprecipitation method  

Microsoft Academic Search

Magnetic nanoparticles of cobalt ferrite (CoFe2O4) have been synthesized in a homogeneous aqueous solution without any template and subsequent heat treatment. The average particle size could be varied in the range of 2-14nm by controlling coprecipitation temperature of Co2+ and Fe3+ ions in alkaline solution although the size distribution is pretty wide. As the precipitation temperature increased in the range

Yeong Il Kim; Don Kim; Choong Sub Lee

2003-01-01

286

Ferrocenyl branched poly (ethylene imine) micelles as reductive templates for the preparation of silver nanoparticles  

Microsoft Academic Search

Polymeric micelles with a branched poly (ethylene imine) shell and a reductive ferrocene core were prepared via self-assembly\\u000a of ferrocene modified branched poly (ethylene imine) (BPEI-Fc). The well-controlled polymeric micelles with a reductive core\\u000a were used as templates to prepare core–shell-structured silver nanoparticles (AgNPs) in aqueous solution. The as-prepared\\u000a nanoparticles were characterized by UV–Vis spectrophotometer, transmission electron microscope (TEM), selected-area

Lei-ze ZhuWen-bo; Wen-bo Zhou; Jian Ji

2010-01-01

287

NMR-D study of the local spin dynamics and magnetic anisotropy in different nearly monodispersed ferrite nanoparticles  

NASA Astrophysics Data System (ADS)

We present a systematic experimental comparison of the superparamagnetic relaxation time constants obtained by means of dynamic magnetic measurements and 1H-NMR relaxometry, on ferrite-based nanosystems with different composition, various core sizes and dispersed in different solvents. The application of a heuristic model for the relaxivity allowed a comparison between the reversal time of magnetization as seen by NMR and the results from the AC susceptibility experiments, and an estimation of fundamental microscopic properties. A good agreement between the NMR and AC results was found when fitting the AC data to a Vogel-Fulcher law. Key parameters obtained from the model have been exploited to evaluate the impact of the contribution from magnetic anisotropy to the relaxivity curves and estimate the minimum approach distance of the bulk solvent.

Bordonali, L.; Kalaivani, T.; Sabareesh, K. P. V.; Innocenti, C.; Fantechi, E.; Sangregorio, C.; Casula, M. F.; Lartigue, L.; Larionova, J.; Guari, Y.; Corti, M.; Arosio, P.; Lascialfari, A.

2013-02-01

288

NMR-D study of the local spin dynamics and magnetic anisotropy in different nearly monodispersed ferrite nanoparticles.  

PubMed

We present a systematic experimental comparison of the superparamagnetic relaxation time constants obtained by means of dynamic magnetic measurements and (1)H-NMR relaxometry, on ferrite-based nanosystems with different composition, various core sizes and dispersed in different solvents. The application of a heuristic model for the relaxivity allowed a comparison between the reversal time of magnetization as seen by NMR and the results from the AC susceptibility experiments, and an estimation of fundamental microscopic properties. A good agreement between the NMR and AC results was found when fitting the AC data to a Vogel-Fulcher law. Key parameters obtained from the model have been exploited to evaluate the impact of the contribution from magnetic anisotropy to the relaxivity curves and estimate the minimum approach distance of the bulk solvent. PMID:23315450

Bordonali, L; Kalaivani, T; Sabareesh, K P V; Innocenti, C; Fantechi, E; Sangregorio, C; Casula, M F; Lartigue, L; Larionova, J; Guari, Y; Corti, M; Arosio, P; Lascialfari, A

2013-01-11

289

Preparation and Characterization of FeCo Alloy Nanoparticles  

Microsoft Academic Search

FeCo alloy nanoparticles were synthesized by a new reduction process in liquid phase with sodium borohydride and L-ascorbic acid as reductant, and cetyltrimethylammonium bromide as surfactant. The structure and magnetic properties of the samples were investigated by laser particle size analyzer, X-ray powder diffraction, transmission electron microscopy, selected-area electron diffraction and vibrating sample magnetometer. The nanoparticles obtained are nearly spherical

Fengping Wang; Xinghua Xue; Guizhen Wang; Jingyao Cai; Xin Fu

2011-01-01

290

Magnetic nanoparticles produced by surfactant-assisted ball milling  

Microsoft Academic Search

However, the size distribution of the particles obtained by ball milling can be quite wide compared with the chemical methods. The chemical methods, nevertheless, have had lim- ited success in the synthesis of hard magnetic nanoparticles of rare-earth compounds.7,8 Traditionally, surfactant-assisted ball milling technique has been used mainly for preparing ferrite nanoparticles, and not many studies have been con- ducted

V. M. Chakka; B. Altuncevahir; Z. Q. Jin; Y. Li; J. P. Liua

291

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

NASA Astrophysics Data System (ADS)

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).

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

2009-06-01

292

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

PubMed

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

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

2013-02-10

293

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

294

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

NASA Astrophysics Data System (ADS)

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

Khan, Saeed Ahmad; Schneider, Marc

2013-02-01

295

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

296

Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method  

NASA Astrophysics Data System (ADS)

The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution.

Bobadilla, L. F.; García, C.; Delgado, J. J.; Sanz, O.; Romero-Sarria, F.; Centeno, M. A.; Odriozola, J. A.

2012-11-01

297

Microstructure and Magnetic Properties of Iron Oxide Nanoparticles Prepared by Wet Chemical Method  

Microsoft Academic Search

The magnetic properties of iron oxide nanoparticles prepared by the chemical decomposition of the iron chlorides with the ratio Fe3+\\/Fe2+=2.25 were studied by means of transmission electron microscopy, X-ray diffraction and Mössbauer spectroscopy in- and without external magnetic field. The transmission electron microscopy studies show that the nanoparticles have spherical shape with diameter about 13 nm. The transmission electron microscopy

D. Satula; B. Kalska-Szostko; K. Szymanski; L. Dobrzynski; J. Kozubowski

2008-01-01

298

Preparation of MnO 2 nanoparticles by directly mixing potassium permanganate and polyelectrolyte aqueous solutions  

Microsoft Academic Search

Well-stable MnO2 nanoparticles were prepared by directly mixing potassium permanganate and polyelectrolyte aqueous solutions, with the use of polyelectrolyte to serve both as a reducing agent and a protective agent. Such nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS), and their growth kinetics was further traced by in situ UV–vis spectra.

Yonglan Luo

2007-01-01

299

Poly(amidoamine)-G5 dendrimers\\/noble metal gold hybrid nanoparticles prepared by ?-ray irradiation  

Microsoft Academic Search

In the absence of a chemical reductant and other protective reagents, noble metal gold hybrid nanoparticles are successfully prepared by 60Co ?-ray irradiation using fifth-generation poly(amidoamine) dendrimer with surface amine-terminated group as polymeric template. The zerovalent gold is of spherical structure and the particle size is on nanometer scale range of 3–12 nm. The size distribution of gold nanoparticles displays multidispersity.

Kangming Nie; Jinlian Hu; Wenmin Pang; Qingren Zhu

2007-01-01

300

Surface-modified superparamagnetic nanoparticles for drug delivery: preparation, characterization, and cytotoxicity studies.  

PubMed

Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging (MRI) contrast agents or in drug delivery applications. In this study, a novel approach to prepare magnetic polymeric nanoparticles with magnetic core and polymeric shell using inverse microemulsion polymerization process is reported. Poly(ethyleneglycol) (PEG)-modified superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared inside the aqueous cores of AOT/n-Hexane reverse micelles and characterized by various physicochemical means such as transmission electron microscopy (TEM), infrared spectroscopy, atomic force microscopy (AFM), vibrating sample magnetometry (VSM), and ultraviolet/visible spectroscopy. The inverse microemulsion polymerization of a polymerizable derivative of PEG and a cross-linking agent resulted in a stable hydrophilic polymeric shell of the nanoparticles. The results taken together from TEM and AFM studies showed that the particles are spherical in shape with core-shell structure. The average size of the PEG-modified nanoparticles was found to be around 40-50 nm with narrow size distribution. The magnetic measurement studies revealed the superparamagnetic behavior of the nanoparticles with saturation magnetization values between 45-50 electromagnetic units per gram. The cytotoxicity profile of the nanoparticles on human dermal fibroblasts as measured by standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the particles are nontoxic and may be useful for various in vivo and in vitro biomedical applications. PMID:15382647

Gupta, Ajay Kumar; Wells, Stephen

2004-03-01

301

Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route  

Microsoft Academic Search

The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared\\u000a via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH3COO)2·2H2O) and aniline (C6H5NH2) in 6 h refluxing at ?65 °C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed.

Rizwan Wahab; Amrita Mishra; Soon-Il Yun; Young-Soon Kim; Hyung-Shik Shin

2010-01-01

302

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

PubMed Central

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

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

303

[Preparation and application of CuS/Cu2+ nanoparticles as a resonance light scattering probe].  

PubMed

Cuprum-enriched cuprum sulfide nanoparticles (CuS/Cu2+) were prepared. The nanoparticles are water-soluble. They could be used as a resonance light scattering (RLS) probe in the determination of human gamma globulin, which was proved to be a simple, rapid and specific method. In comparison with organic dye probes, these nanoparticles probes are brighter, more stable against photobleaching, and do not suffer from blinking. Under optimum conditions, the response is linearly proportional to the concentration of gamma globulin between 0.1 and 1.5 mg x L(-1), and the detection limit is 0.064 6 mg x L(-1). PMID:16241064

Xu, Fa-gong; Wang, Lun; Wang, Le-yu; Chen, Hong-qi; Zhang, Li; Liu, Jin-shui

2005-07-01

304

Preparation and properties of superparamagnetic nanoparticles with narrow size distribution and biocompatible  

NASA Astrophysics Data System (ADS)

A chemical co-precipitation method capable of controlling the average size and size distribution of magnetic Fe3O4 nano-particles was developed. It was found that the homogeneous variation of the pH value in the solution plays a role in the size distribution of the synthesized Fe3O4 particles. In this work, we added urea to the ferrite solution, followed by heating the solution to decompose the urea before titrating a base solution into the ferrite solution. Thus, the variation in pH value in the solution can become uniform, and the uniformity in the particles size can be greatly enhanced. In addition, the average particle size is adjustable via control of the amount of urea decomposing at one time. To be biocompatible, dextran is selected as the surfactant for the Fe3O4 particles, because of its non-toxicity and high bio-affinity. The desired bio-probes can be coated on the dextran layer through adequate chemical reactions.

Jiang, Wanquan; Yang, H. C.; Yang, S. Y.; Horng, H. E.; Hung, J. C.; Chen, Y. C.; Hong, Chin-Yih

2004-12-01

305

Preparation of novel magnetic fluorescent nanoparticles using amino acids.  

PubMed

Nanotechnology has opened new gates to pharmaceutical sciences and medicine from the aspect of drug delivery and imaging systems. Currently, bimodal fluorescent-magnetic nanoparticles are of great interest to biomedical scientists. In order to constructing these kinds of nanoparticles, fluorescent molecules should be linked to a magnetic core, while luminescence quenching is prevented. In order to alleviate this effect, usually fluorescent molecules are attached to a magnetic core after a multistep hydrocarbon, polymer or silica coating, which significantly increases the particle's size and reduces its magnetic saturation value. In this study, for the first time, amino acids (L-lysine and L-arginine) have been used as a linker and spacer between a fluorescent molecule (FITC) and a magnetic nanoparticle (Fe(3)O(4)) in a simple, two-step synthesis. Also, 3-aminopropyltriethoxysilane (APTES) was used without any previous silica coating for fluorescent magnetic nanoparticles construction. Routinely APTES is used after silica coating by tetraethoxysilane (TEOS). Either of L-lysine, L-arginine and APTES coating provides surface functional groups which interact with the isothiocyanate group of FITC. According to the obtained results, amino acids could be used for successful construction of fluorescent magnetic nanoparticles in a simple synthesis pathway, without any significant impact on the excitation and emission properties of fluorescent molecule. PMID:23104022

Ebrahiminezhad, Alireza; Ghasemi, Younes; Rasoul-Amini, Sara; Barar, Jaleh; Davaran, Soodabeh

2012-09-05

306

Alginic acid nanoparticles prepared through counterion complexation method as a drug delivery system.  

PubMed

In this paper, a kind of novel alginic acid nanoparticles was successfully prepared by a non-solvent-aided counterion complexation between anionic alginic acid and cationic 2,2'-(ethylenedioxy)diethylamine in aqueous solution followed by cross-linking alginic acid moiety using Ca(2+). It was found that these alginic acid nanoparticles have a spherical morphology with the diameter of about 100 nm, and negatively charged surface with the zeta potential of about -30 mV. Compared to the desintegrity of un-cross-linked nanoparticles, the Ca(2+)-cross-linked nanoparticles maintained their integrity in the aqueous medium with the physiological pH value. Doxorubicin, a model antitumor drug, was successfully loaded into the alginic acid nanoparticles, and their in vitro and in vivo antitumor activities were evaluated. It was found that these negatively charged nanoparticles could be taken up by the cancer cells through an endocytosis mechanism. In vivo near-infrared (NIR) fluorescence imaging and biodistribution examinations showed that the alginic acid nanoparticles could be well-accumulated in the tumor site by the enhanced permeability and retention effect. In vivo antitumor examination showed that the drug-loaded nanoparticles have superior efficacy in impeding tumor growth and prolonging the lifetime of H22 tumor-bearing mice than free drug. PMID:23020277

Cheng, Yuan; Yu, Shuling; Zhen, Xu; Wang, Xin; Wu, Wei; Jiang, Xiqun

2012-10-11

307

Mössbauer study of nano-particles of spinel ferrites Li xFe 3-xO4  

Microsoft Academic Search

Mössbauer spectra have been recorded on three nano-particle samples in the series Li xFe 3-xO4 (for x = 0.1, 0.2 and 0.3) at 300K and 80K. Spectra could be resolved into two doublets attributed to two crystalline sites, viz., tetrahedral site and octahedral site. Li occupies the octahedral site with a complete preference as in the bulk particle size state.

Subhash Chander; M P Sharma; Anjali Krishnamurthy; Bipin K Srivastava

308

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

PubMed

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

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

2013-08-01

309

Preparation and characterization of curcumin-piperine dual drug loaded nanoparticles  

PubMed Central

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

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

2012-01-01

310

Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment  

ERIC Educational Resources Information Center

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

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

2012-01-01

311

Preparation of Gold Nanoparticles Using Tea: A Green Chemistry Experiment  

ERIC Educational Resources Information Center

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

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

2012-01-01

312

Preparation of near-infrared light absorbing gold nanoparticles using polyethylene glycol-attached dendrimers.  

PubMed

The photochemical properties of gold nanoparticles (Au NPs) are largely influenced by their size and morphology. Stably dispersed Au NPs that absorb near-infrared (NIR) light are useful for biomedical applications. We prepared well-dispersed NIR-absorbing Au NPs using seeding growth from Au NPs encapsulated in polyethylene glycol (PEG)-attached dendrimers. Formaldehyde was used as a reductant to prepare gold nanoparticles with convex-concave surfaces. Low pH and an appropriate amount of gold ion were required to prepare Au NPs that absorbed NIR-light. Interestingly, the encapsulation of Au NPs within the PEGylated dendrimers was important for preparation of NIR-absorbing Au NPs. Transmission electron microscope (TEM) analysis showed that these Au NPs had convex-concave surfaces and large diameters. This paper presents a novel preparation method for NIR-responsive Au NPs by reduction with formaldehyde. PMID:20801621

Kojima, Chie; Umeda, Yasuhito; Harada, Atsushi; Kono, Kenji

2010-08-06

313

Preparation and in vitro anticancer activity of oxymatrine mixed micellar nanoparticles.  

PubMed

The aim of this study was to prepare oxymatrine (OMT) mixed micellar nanoparticles to delay release of the drug and enhance its cytotoxicity against cancer cells. A co-solvent evaporation method using lipoid E80, lipoid S75, MPEG-PLA and Poloxamer 188 was chosen to prepare the OMT formulation, and its release characteristics, cytotoxic activity in vitro and physical characteristics were evaluated. The results showed that OMT mixed micellar nanoparticles have sustained release and cytotoxic activity in vitro to the SMMC-7721 cell line. PMID:21812325

Jin, Nan; Zhao, Yong-Xing; Deng, Shu-Hua; Sun, Qian

2011-07-01

314

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

NASA Astrophysics Data System (ADS)

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.

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

2009-09-01

315

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

PubMed Central

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.

2009-01-01

316

Preparation and characteristics of Fe3O4-encapsulated BaTiO3 powder by ultrasound-enhanced ferrite plating  

NASA Astrophysics Data System (ADS)

Fe3O4-encapsulated BaTiO3 composite powders were prepared with ultrasound-enhanced ferrite plating. It was observed that Fe3O4 particles of a single magnetite phase grew in a spherical form on BaTiO3 grains. Microwave absorbing behavior of the composite powders depended strongly on a plating condition such as the concentration of buffer (CH3COONH4) solution. When the buffer concentration was 0.2M, Fe3O4 particles densely coated the BaTiO3 grains, which in turn exhibited two microwave absorption bands at 8 and 13GHz with the reflection losses of -24 and -8dB, respectively.

Choi, S. H.; Oh, J. H.; Ko, T.

2004-05-01

317

Preparation and characteristics of a magnetic-dielectric (Fe3O4/BaTiO3) composite by ferrite plating with ultrasound irradiation  

NASA Astrophysics Data System (ADS)

Fe3O4-encapsulated BaTiO3 powder was synthesized with ultrasound-enhanced ferrite plating. The microwave absorbing properties of the synthesized Fe3O4/BaTiO3 composite powder were compared with the following powders, Fe3O4, Fe3O4/BaTiO3 mixed, and BaTiO3. The absorption bands for their specimens having the same thickness were observed at 6.9 GHz, 11.1 GHz, 8.3 GHz, and 5.8 GHz, respectively. When ultrasound was applied for more than 3 hours, Fe3O4 particles covered completely the surface of each BaTiO3 grain. The permittivity and the corecive force of a sintered composite prepared from this Fe3O4-encapsulated BaTiO3 powder was 148.38-362.4 at 10 kHz and 2920-3600 Oe, respectively.

Park, H. K.; Choi, S. H.; Oh, J. H.; Ko, T.

2004-06-01

318

Comparative study of structural and magnetic properties of NiZnCu ferrite powders prepared via chemical coprecipitation method with different coprecipitators  

NASA Astrophysics Data System (ADS)

We prepared NiZnCu ferrite powders with nominal composition Ni0.4-xZn0.6CuxFe2O4 (x=0-0.2) via chemical coprecipitation method with NaOH and Na2CO3 as coprecipitators. The structural and magnetic properties of these compounds were studied and compared. It is found that all the specimens exhibit single-phase structure after annealing. The saturation magnetization of specimens with NaOH as coprecipitator is lower than that with Na2CO3 as coprecipitator. It is also found that the growth of grains is hindered for specimens using Na2CO3 as coprecipitator.

Xia, Ailin; Jin, Chuangui; Du, Dexin; Zhu, Guohui

2011-06-01

319

Nanodimensional spinel NiFe2O4 and ZnFe2O4 ferrites prepared by soft mechanochemical synthesis  

NASA Astrophysics Data System (ADS)

NiFe2O4 and ZnFe2O4 ferrites have been prepared by soft mechanochemical synthesis. The formation of spinel phase and crystal structure of sintered powders were analyzed by X-ray diffraction, Raman spectroscopy, and transmission microscopy. In order to confirm phase formation and cation arrangement, Mössbauer measurements were done. Investigation of the magnetization as a function of magnetic field confirms an expected change of the degree of inversion in the spinel structure with the sintering. The electrical DC/resistivity/conductivity was measured in the temperature range of 298-423 K. Impedance spectroscopy was performed in the wide frequency range (100 Hz-10 MHz) at different temperatures.

Ž. Lazarevi?, Z.; Jovaleki?, ?.; Milutinovi?, A.; Sekuli?, D.; Ivanovski, V. N.; Re?nik, A.; Ceki?, B.; Ž. Rom?evi?, N.

2013-05-01

320

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

321

Synthesis and magnetic properties of the size-controlled Mn–Zn ferrite nanoparticles by oxidation method  

Microsoft Academic Search

Size-controlled Mn0.67Zn0.33Fe2O4 nanoparticles in the wide range from 80 to 20nm have been synthesized, for the first time, using the oxidation method. It has been demonstrated that the particle size can be tailor-made by varying the concentration of the oxidant. The magnetization of the 80nm particles was 49Am2kg?1 compared to 34Am2kg?1 for the 20nm particles. The Curie temperatures for all

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

2006-01-01

322

Core–shell silica@chitosan nanoparticles and hollow chitosan nanospheres using silica nanoparticles as templates: Preparation and ultrasound bubble application  

Microsoft Academic Search

This work reports the preparation of chitosan hollow nanospheres and their uses as the ultrasound-induced imaging agents. Reaction of chitosan to the 4-isocyanato-4?-(3,3-dimethyl-2,4-dioxo-azetidino)diphenylmethane modified silica nanoparticles forms silica@chitosan core shell nanoparticles. Removal of the silica cores with hydrofluoride generates the chitosan hollow nanospheres. Structures and morphology of the silica@chitosan core–shell nanoparticles and chitosan hollow nanospheres are characterized with an X-ray

Ying-Ling Liu; Yen-Hsing Wu; Wei-Bor Tsai; Chih-Chi Tsai; Wen-Shiang Chen; Chuan-Shao Wu

2011-01-01

323

Microwave absorbing properties of ferrite-based nanocomposites  

NASA Astrophysics Data System (ADS)

A study of the microwave absorbing properties of polymer (epoxy) based nanocomposites is presented. The ferrite nanoparticles employed as filler materials were produced by a co-precipitation method, which was designed for production of large amounts at low cost. The absorbing properties of different kinds of ferrite nanoparticles, soft (manganese) and hard (cobalt) magnetic nanoparticles, are compared. In addition, the impact of high and low densities of the respective ferrite type has been investigated. Our analysis of the microwave absorbing properties is made over a wide frequency band including both MHz and GHz regions, which is of high interest for a number of different applications both military and civilian.

Jänis, A.; Olsson, R. T.; Savage, S. J.; Gedde, U. W.; Klement, U.

2007-04-01

324

Optimization of dye-doped silica nanoparticles prepared using a reverse microemulsion method.  

PubMed

Fluorescent labeling based on silica nanoparticles facilitates unique applications in bioanalysis and bioseparation. Dye-doped silica nanoparticles have significant advantages over single-dye labeling in signal amplification, photostability and surface modification for various biological applications. We have studied the formation of tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)) dye-doped silica nanoparticles by ammonia-catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) in water-in-oil microemulsion. The fluorescence spectra, particle size, and size distribution of Ru(bpy) dye-doped silica nanoparticles were examined as a function of reactant concentrations (TEOS and ammonium hydroxide), nature of surfactant molecules, and molar ratios of water to surfactant (R) and cosurfactant to surfactant (p). The particle size and fluorescence spectra were dependent upon the type of microemulsion system chosen. The particle size was found to decrease with an increase in concentration of ammonium hydroxide and increase in water to surfactant molar ratio (R) and cosurfactant to surfactant molar ratio (p). This optimization study of the preparation of dye-doped silica nanoparticles provides a fundamental knowledge of the synthesis and optical properties of Ru(bpy) dye-doped silica nanoparticles. With this information, these nanoparticles can be easily manipulated, with regard to particle size and size distribution, and bioconjugated as needed for bioanalysis and bioseparation applications. PMID:15350111

Bagwe, Rahul P; Yang, Chaoyong; Hilliard, Lisa R; Tan, Weihong

2004-09-14

325

Preparation of ZnO nanoparticles in a reverse micellar system and their photoluminescence properties.  

PubMed

ZnO nanoparticles with spherical morphology and narrow size distribution were obtained by calcination of Zn(OH)2 nanoparticles, which were prepared in a polyethylene glycol mono-4-nonylphenyl ether (NP-5)/cyclohexane reverse micellar system and incorporated into polyurea (PUA) via an in situ polymerization of hexamethylene diisocyanate (HDI). The resulting ZnO nanoparticles demonstrated a near-UV emission and a green emission, the intensity ratio of which depended on calcination conditions. For the nanoparticles studied, the calcination atmosphere influenced remarkably the photoluminescence properties such as intensity ratio of the near-UV emission to green emission, rather than the size, morphology, and crystallinity of the ZnO nanoparticles. The green emission decreased by calcination in O2 flow but increased by calcination in N2 flow, as compared with the case calcined in air flow. This finding suggests that the green emission is enhanced with the increase of the number of oxygen vacancies of the ZnO nanoparticles and thus the photoluminescence properties of the nanoparticles were successfully controlled by the calcination condition, without changing the size and morphology. PMID:15752800

Hirai, Takayuki; Asada, Yoko

2005-04-01

326

Preparation and characterization of surface-coated ZnS nanoparticles  

SciTech Connect

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

Chen, S.; Liu, W.

1999-11-09

327

Preparation and antibacterial activity of Fe3O4@Ag nanoparticles  

NASA Astrophysics Data System (ADS)

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

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

2007-07-01

328

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

329

Third order optical nonlinearity and diffraction pattern of Ni nanoparticles prepared by laser ablation  

NASA Astrophysics Data System (ADS)

In this article we studied all-optical Kerr effect of Ni nanoparticles immersed in ethanol using z-scan method. The nanoparticles were prepared by high frequency pulsed laser ablation. UV-Visible optical absorption spectroscopy and SEM observation were employed for characterization and studying the morphology of Ni nanoparticles. Analysis of scanning electron microscopy (SEM) images showed that the synthesized nanoparticles shape were dominantly spherical, varying from 19 nm to 40 nm for 1 mJ pulse energy. The nonlinear absorption and refraction indices were measured using open- and closed-aperture z-scan techniques, with both CW and pulsed irradiations. In both regimes results were studied. Furthermore, diffraction rings pattern as a result of nonlinear refraction was observed. We suggested an opportunity to form a new nonlinear-optical media for nonlinear optical applications.

Alikhani, S.; Tajalli, H.; Koushki, E.

2013-01-01

330

SOFT MAGNETIC PROPERTIES OF Mg0.7-xNi0.3ZnxFe2O4 FERRITES SYNTHESIZED BY SOL-GEL AUTO-COMBUSTION TECHNIQUE WITHOUT POST-PREPARATION THERMAL TREATMENT  

NASA Astrophysics Data System (ADS)

Single phase nanocrystalline soft magnetic Mg0.7-xNi0.3ZnxFe2O4, ferrites with x = 0.0 - 0.7 were prepared by sol gel auto-combustion method. X-ray diffraction confirms the formation of single phase nano-crystalline cubic spinel ferrites with average grain diameter ranging between 12.9 nm to 23.9 nm. Formation of the ferrite phase without subsequent heat treatment makes sol-gel auto combustion technique especially suitable and economical for the large scale industrial production of the nano-crystalline ferrites for multilayer chip inductor applications (MLCI). Both, lattice parameter and X-ray density shows a linear increase with increasing Zn2+ concentration, attributed to the difference in ionic radii and density of Mg and Zn. Increase in Zn content enhances the soft magnetic behavior, exhibiting linear decrease of coercivity from 122.34 Oe to 72.45 Oe, explained by increase of density with Zn addition. The maximum magnetization (Mmax)increases up to 0.106 Tesla (for x = 0.4) and. then decreases with increase of Zn content, discussed on the basis of increase of the occupancy of A-site in spinel ferrite by non-magnetic Zn2+ ion.

Ghosh, A.; Satalkar, M.; Rathod, S.; Nag, S. P.; Vyas, P.; Kane, N.; Ghodke, N.; Prasad, R.; Dwivedi, R.

331

Preparation and characterization of polymeric and lipid nanoparticles of pilocarpine HCl for ocular application.  

PubMed

Pilocarpine is used topically in the treatment of glaucoma. Various studies were performed to improve the bioavailability and prolong the residence time of drugs in ocular drug delivery. Drug loaded polymeric and lipid nanoparticles offer several favourable biological properties, such as biodegradability, nontoxicity, biocompatibility and mucoadhesiveness. Therefore, preparing positively-charged pilocarpine HCl-loaded polymeric and lipid nanoparticles was the purpose of this study. Nanoparticles were prepared by quasi-emulsion solvent evaporation technique. The non-biodegradable positively-charged polymer Eudragit(®) RS 100 and semi-solid lipid excipient Gelucire(®) 44/14 were used as a vehicle, the cationic lipid octadecylamine was used as a cationic agent. The formulations were evaluated in terms of particle size, size distribution, zeta potential measurement, thermal behavior (Differential Scanning Calorimetry DSC), entrapment efficacy and pH. Characterizations of nanoparticles were analyzed during the storage period of 6 months for stability tests. Polymeric and lipid nanoparticles could be prepared successfully promising their use for ophthalmic delivery. PMID:22813238

Lütfi, Genç; Müzeyyen, Demirel

2012-07-20

332

Preparation of anatase/rutile mixed-phase titania nanoparticles for dye-sensitized solar cells.  

PubMed

Acid-labile high surface mesoporous ZnO/Zn(OH)2 composite material is used as a novel hard template for the preparation of mesoporous amorphous TiO2. The template-free amorphous TiO2 material is then thermally crystallized at suitable temperature to control the relative ratio of anatase and rutile phases in a particle. Four different anatase/rutile (AR) mixed-phase TiO2 nanoparticles (AR-3, AR-15, AR-20, and AR-23 denoted for the samples of 3%, 15%, 20%, and 23% rutile phase, respectively) are prepared and characterized by powder X-ray diffraction (PXRD) and transmission electron microscopy (TEM). The coexistence of anatase and rutile phases in a TiO2 nanoparticle is visually confirmed by HRTEM analysis. These mixed-phase TiO2 nanoparticles are examined as candidates for photoelectrodes of dye-sensitized solar cells (DSSCs). The J-V curves and IPCE spectra for the DSSCs prepared from the mixed-phase TiO2 nanoparticles are obtained, and their photovoltaic properties are investigated. The photo-conversion efficiency (eta) indicates the highest value of 5.07% for AR-20. The synergistic effect of coexisting anatase and rutile phases with an optimal ratio in a TiO2 nanoparticle of AR-20 for an efficient interfacial transfer of photo-generated electrons is likely to lead to the highest efficiency among the AR-n samples. PMID:23755675

Hwang, Yong-Kyung; Park, Sung Soo; Lim, Jun-Heok; Won, Yong Sun; Huh, Seong

2013-03-01

333

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

PubMed Central

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

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

2013-01-01

334

Preparation and Characterization of Stimuli-Responsive Magnetic Nanoparticles  

PubMed Central

In this work, the main attention was focused on the synthesis of stimuli-responsive magnetic nanoparticles (SR-MNPs) and the influence of glutathione concentration on its cleavage efficiency. Magnetic nanoparticles (MNPs) were first modified with activated pyridyldithio. Then, MNPs modified with activated pyridyldithio (MNPs-PDT) were conjugated with 2, 4-diamino-6-mercaptopyrimidine (DMP) to form SR-MNPs via stimuli-responsive disulfide linkage. Fourier transform infrared spectra (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize MNPs-PDT. The disulfide linkage can be cleaved by reduced glutathione (GHS). The concentration of glutathione plays an important role in controlling the cleaved efficiency. The optimum concentration of GHS to release DMP is in the millimolar range. These results had provided an important insight into the design of new MNPs for biomedicine applications, such as drug delivery and bio-separation.

2008-01-01

335

Targeted Administration of Proteic Drugs. I. Preparation of Polymeric Nanoparticles  

Microsoft Academic Search

The formulation of hybrid nanoparticles based on synthetic polymer-protein hybrid matrices for the targeted release of proteic drugs with antiviral activity such as a-interferon was investigated. Human serum albumin, alone, or in combination with myoglobin, and the hemiesters of alternating copolymers of maleic anhydride\\/alkyl vinyl ethers of oligo(ethylene glycol) were selected as proteic and synthetic components, respectively. Digalactosyl diacyl gycerol,

Emo Chiellini; Elisabetta E. Chiellini; Federica Chiellini; Roberto Solaro

2001-01-01

336

Chitosan Nanoparticles: Preparation and Application in Antibacterial Paper  

Microsoft Academic Search

Chitosan nanoparticles (CSNP) were obtained by H2O2 degradation of chitosan. Their morphology and size were determined by atomic force microscope (AFM), and the particles were found smooth and approximately 36 nm in size. CSNP-0.5% HAc solutions (1, 2, 5, and 10 mg\\/mL) were used in antibacterial paper by addition in pulp, impregnation, dispersion coating on the handsheets, and insufflation. The

Ying Ma; Pengtao Liu; Chuanling Si; Zhong Liu

2010-01-01

337

Ferrite Catalyst.  

National Technical Information Service (NTIS)

According to this invention, a catalyst consisting of a spinel-type ferrite and having an apparent density of 3.0 g/cm exp 3 can be produced by sintering a mixture of lamellar alpha -Fe sub 2 O sub 3 and other metal oxides. Partly because of the use of a ...

K. Kugimiya Y. Terada

1983-01-01

338

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

SciTech Connect

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

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

2012-12-24

339

Paclitaxel-loaded lipid nanoparticles prepared by solvent injection or ultrasound emulsification.  

PubMed

Lipid nanoparticles were fabricated as an injectable carrier system for paclitaxel. The components for the lipid matrix were based on phospholipids, and sucrose fatty acid ester was used as an emulsifier. Formulation prepared with solvent injection has a slightly larger particle size (187.6 nm) than the formulation (147.7 nm) prepared with ultrasound emulsification. Differential scanning calorimetry results indicated that paclitaxel entrapped in the lipid nanoparticles existed in an amorphous state in the lipid matrix. In vitro drug release was rather slow; only 12.5-16.5% of the drug released from the formulations within 14 days. Lipid nanoparticles demonstrated their potential as a promising pharmaceutical formulation of paclitaxel. PMID:17012121

Arica Yegin, Betül; Benoît, Jean-Pierre; Lamprecht, Alf

2006-10-01

340

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

Microsoft Academic Search

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

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

2009-01-01

341

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

PubMed Central

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

Errico, Cesare; Gazzarri, Matteo; Chiellini, Federica

2009-01-01

342

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

PubMed

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

Li, Yan; Zhang, Xiangmin; Deng, Chunhui

2013-08-09

343

In situ synthesis of cobalt ferrite nanoparticle/polymer hybrid from a mixed Fe-Co methacrylate for magnetic hyperthermia  

NASA Astrophysics Data System (ADS)

Hyperthermic CoFe2O4 nanoparticle (CFO NP)/polymer hybrids were synthesized by hydrolysis-condensation from a complex of Co and Fe possessing methacrylate ligands. Single-crystal analysis revealed that the complex consisted of two Co and four Fe metal atoms coordinated by methacrylate and 2-methoxyethoxy groups. The complex was copolymerized with 2-hydroxyethyl methacrylate (HEMA) and the resulting copolymer was then hydrolyzed to form a CFO NP/copolymer of poly(methacrylate) and poly(2-hydroxyethyl methacrylate) hybrid. Copolymerization with HEMA enhanced the stability of the hybrid in water. The size and magnetic properties of CFO in the hybrid were controlled by adjusting the hydrolysis conditions. Moreover, the hybrid generated heat under an alternating current magnetic field; its exothermal properties depended on the magnetic properties of the hybrid, the strength of the applied field, and the CFO NP content in the agar phantom matrix.

Hayashi, Koichiro; Maeda, Kazuki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

2012-09-01

344

Preparation of Y2O3:Er,Yb nanoparticles by laser ablation in liquid  

NASA Astrophysics Data System (ADS)

We prepared a Y2O3:Er,Yb nanoparticles by laser ablation in liquid. The laser used the second harmonic generation Nd:YAG (532 nm). A preparation process and measurement of upconversion properties were performed by varying the range of the energy density of the laser. Images from scanning electron microscopy (SEM) indicated that two types of nanoparticles existed in the product of laser ablation in liquid. We concluded the following: one type of nanoparticles was prepared from the nucleation of materials in a plume and the other was prepared by fragmentation. In the photoluminescence spectra, green (2H11/2, 4S3/2 ? 4I15/2) and red (4F9/2 ? 4I15/2) fluorescence were observed using a 980 nm laser diode (LD) as the excitation source. We confirmed that the fluorescence intensity increased with increasing energy density of the laser. Thus, we concluded that the number of the nanoparticles increased as the energy density of the laser was increased.

Nunokawa, Takashi; Onodera, Yuji; Hara, Masahiko; Kitamoto, Yoshitaka; Odawara, Osamu; Wada, Hiroyuki

2012-11-01

345

A facile method to prepare heparin-functionalized nanoparticles for controlled release of growth factors  

Microsoft Academic Search

A new, facile method to prepare the heparin-functionalized PLGA nanoparticle (HEP-PLGA NP) for the controlled release of growth factors is developed. This system is composed of PLGA as a hydrophobic core, Pluronic F-127 as a hydrophilic surface layer, and heparin as the functional moiety. HEP-PLGA NPs were prepared by a solvent-diffusion method without chemical modification of the components. The entrapment

Yong-Il Chung; Giyoong Tae; Soon Hong Yuk

2006-01-01

346

Preparation of Highly Oil-Absorbing Resins Consisting of Hollow Nanoparticle Aggregates by Spray Drying  

Microsoft Academic Search

We report on the preparation of a novel poly(styrene-dodecyl methacrylate) (P(St-DMA)) absorbent resin by spray drying. The microstructures of the prepared resins have been examined by scanning electron microscope (SEM), showing that the resins consisted of hollow micrometer-sized spheres that were aggregated by nanoparticles. Meanwhile, the effects of the content of the cross-linker divinybenzene (DVB) on the oil absorption capacity,

Kaibing Huang; Xia Xiao; Zhenhua Chen; Jin Li

2009-01-01

347

Preparation and distribution of 5-fluorouracil 125I sodium alginate-bovine serum albumin nanoparticles  

Microsoft Academic Search

AIM To prepare 5-FU sodium alginate 125I bovine serum albumin nanoparticles (BSA NP), to de- termine the radioactive count in different organs of rats at different time points after oral adminis- tration of 5-FU 125I sodium alginate-BSA NP and to calculate the kinetic parameters of its metabolism. METHODS Emulsion solidification method was used to prepare 5-FU 125I sodium alginate-BSA NP,

YI Yi-Mu; YANG Tang-Yu; PAN Wei-Min

348

Characterization of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles  

NASA Astrophysics Data System (ADS)

In this study, we compare the characteristics of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles. The magnetic nanoparticles with ~ 20 nm diameter were distributed in N-isopropylacrylamide (NIPAM) gel prepared using N,N'-methylenebisacrylamide (BIS), ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). Particle distribution and agglomeration characteristics of the prepared ferrogels were investigated using ultra small angle x-ray scattering (USAXS) and transmission electron microscopy (TEM). The ferrogel samples prepared using Fe3O4 and ?-Fe2O3 particles have similar particle distribution. The ferrogels, prepared with ?-Fe2O3 nanoparticles, however, demonstrate significantly different agglomeration characteristics compared to the ferrogels prepared using Fe3O4. In both systems, the agglomerated particles appear to be spherical, with few of those indicating chain like structures. Based on the particle concentration and sizes, the DC SQUID magnetometry data of these samples showed the magnetic moments range between 0.9 to 2.5 emu/g. Details of our results and analysis are presented.

Suthar, Kamlesh J.; Ghantasala, Muralidhar K.; Mancini, Derrick C.; Ilavsky, Jan

2009-03-01

349

Effect of nanoparticle stabilization and physicochemical properties on exposure outcome: acute toxicity of silver nanoparticle preparations in zebrafish (Danio rerio).  

PubMed

Nanotechnology has vast potential for expanded development and novel application in numerous sectors of society. With growing use and applications, substantial production volumes and associated environmental release can be anticipated. Exposure effect of nanoparticles (NP) on biological systems may be intrinsic to their physicochemical properties introducing unknown associated risk. Herein, we expand the knowledge of health and environmental impact of silver nanoparticles (AgNPs), testing the acute toxicity of 14 AgNP preparations on developing zebrafish embryos (Danio rerio). Toxicological end points, including mortality, hatching rate, and heart rate were recorded. Concentration, stabilization agent and physicochemical properties were monitored as contributing outcome factors. Our findings indicate wide ranging LC50 24 h postfertilization values (0.487 ppm (0.315, 0.744 95% CI) to 47.89 ppm (18.45, 203.49 95% CI)), and indicate surface charge and ionic dissolution as key contributory factors in AgNP exposure outcome. PMID:23458316

Cunningham, Stephen; Brennan-Fournet, Margaret E; Ledwith, Deirdre; Byrnes, Lucy; Joshi, Lokesh

2013-03-26

350

Chemical Preparation and Characterization of Elemental Cu, Ni, and Cu/Ni Core/Shell Nanoparticles  

NASA Astrophysics Data System (ADS)

Elemental Ni, Cu, and Cu core/Ni shell nanoparticles have been prepared in a polyol-type process. The elemental nanoparticles were prepared by dissolving NiCl2.6H2O and/or CuCl2.2H2O in ethylene glycol (EG) and heating the solution to reflux prior to the addition of NaOH. The resulting precipitate was then extracted, dried, and characterized by scanning electron microscopy (SEM) with elemental analysis, x-ray diffraction (XRD), and in the case of the elemental Ni nanoparticles, vibrating sample magnetometry (VSM) measurements. The best fit lattice parameters obtained from the elemental Ni and Cu nanoparticles were 0.35289(28) and 0.36171(23) nm, respectively, in good agreement with the corresponding bulk values. On the other hand, the measured saturation magnetization of about 49 emu/g was somewhat smaller than the bulk Ni value. In the case of the Cu/Ni nanoparticles, the best fit lattice parameters for the Ni and Cu components of the core/shell structure were 0.35299(26) and 0.36101(10) nm, indicating the formation of an essentially pure Ni shell and a slight amount of Ni incorporation in the Cu core.

Higgins, Laura; Lattanzi, Michael; Kelly, Brian; Poirier, Gerald; Unruh, Karl

2011-03-01

351

Preparation of Biocompatible Carboxymethyl Chitosan Nanoparticles for Delivery of Antibiotic Drug  

PubMed Central

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

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

2013-01-01

352

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

PubMed Central

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

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

2013-01-01

353

Preparation of E-selectin-targeting nanoparticles and preliminary in vitro evaluation.  

PubMed

Targeted delivery aims to concentrate therapeutic agents at their site of action and thereby enhance treatment and limit side-effects. E-selectin on endothelial cells is markedly up-regulated by cytokine stimulation of inflamed and some tumoral tissues, promoting the adhesion of leukocytes and metastatic tumor cells, thus making it an interesting molecular target for drug delivery systems. We report here the preparation of targeted nanoparticles from original amphiphilic block copolymers functionalized with an analog of sialyl Lewis X (SLEx), the physiological ligand of E-selectin. Nanoparticles, prepared by nanoprecipitation, caused no significant cytotoxicity. Ligand-functionalized nanoparticles were specifically recognized and internalized better by tumor necrosis factor ? (TNF-?)-activated human umbilical vein endothelial cells (HUVECs) than control nanoparticles or HUVECs with low E-selectin expression. These nanoparticles are designed to carry the ligand at the end of a PEG spacer to improve accessibility. This system has potential for the treatment of inflammation, inhibition of tumor metastasis, and for molecular imaging. PMID:22322211

Jubeli, Emile; Moine, Laurence; Nicolas, Valérie; Barratt, Gillian

2012-01-23

354

Preparation, drug release and cellular uptake of doxorubicin-loaded dextran-b-poly(?-caprolactone) nanoparticles.  

PubMed

Amphiphilic dextran-b-poly(?-caprolactone) diblock copolymers were synthesized with the purpose of preparing nanocarriers for doxorubicin (DOX), an anticancer drug. The Dex-b-PCL diblock copolymers were synthesized by end-to-end coupling of amino-terminated dextran and aldehyde-terminated poly(?-caprolactone) and characterized by (1)H NMR spectra and gel permeation chromatography. The DOX-loaded Dex-b-PCL nanoparticles were prepared by a modified nanoprecipitation method and characterized by transmission electron microscopy and dynamic light scattering. In vitro release of DOX from DOX-Dex-b-PCL nanoparticles showed a sustained release manner with certain amount of burst release in the first 9h. In vitro cytotoxicity test of DOX-Dex-b-PCL nanoparticles against SH-SY5Y cells showed that DOX is still pharmacologically active after drug loading. The fluorescence imaging results showed that DOX-Dex-b-PCL nanoparticles could be easily uptaken by SH-SY5Y cells. These results indicate that DOX-Dex-b-PCL nanoparticles may be a promising nanocarrier for DOX. PMID:23499079

Li, Bengang; Wang, Qing; Wang, Xin; Wang, Chongzhi; Jiang, Xiqun

2013-01-07

355

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

PubMed

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

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

2012-05-24

356

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

PubMed

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

Song, Chongfu; Sheng, Liangquan; Zhang, Xiaobo

2012-01-12

357

Preparation of rapamycin-loaded chitosan/PLA nanoparticles for immunosuppression in corneal transplantation.  

PubMed

Rapamycin-loaded chitosan/polylactic acid nanoparticles with size of about 300 nm in diameter were prepared through nanoprecipitation method using cholesterol-modified chitosan as a stabilizer. The surface coating of chitosan, which was demonstrated by zeta potential measurement, endowed the nanoparticles good retention ability at the procorneal area, facilitating the sustained release of rapamycin on the corneal. The immunosuppression in corneal transplantation of the nanoparticles was investigated using rabbit as animal model, the median survival time of the corneal allografts treated with nanoparticles was 27.2+/-1.03 days and 50% grafts still remained surviving by the end of the observation, while the group treated with 0.5% rapamycin suspension was 23.7+/-3.20 days. The median survival time of drug-free nanoparticles group and untreated groups were 10.9+/-1.45 and 10.6+/-1.26 days, respectively. The results demonstrated the excellent immunosuppression of rapamycin-loaded chitosan/polylactic acid nanoparticles in corneal transplantation. PMID:17919859

Yuan, Xu-Bo; Yuan, Yan-Bo; Jiang, Wei; Liu, Jie; Tian, En-Jiang; Shun, Hui-Ming; Huang, Ding-Hai; Yuan, Xiao-Yan; Li, Hong; Sheng, Jing

2007-08-11

358

Using the polymeric ouzo effect for the preparation of polysaccharide-based nanoparticles.  

PubMed

The polymeric ouzo effect, a nanoprecipitation process, is used for the preparation of polysaccharide-based nanoparticles. Dextran, pullulan, and starch were esterified with hydrophobic carboxylic acid anhydrides to obtain hydrophobic polysaccharides, which are insoluble in water. The additional introduction of methacroyl residues offers the possibility to cross-link the generated nanostructures, which become insoluble in organic solvents. To make use of the ouzo effect for the formation of nanoparticles, the polymer has to be soluble in an organic solvent, which is miscible with water. Here, acetone and THF were used. Immediately after the organic polymer solution is added to water, nanoparticles are generated. The size of the nanoparticles can be adjusted between 50 and 200 nm by changing the concentration of the initial polysaccharide solution. The degree of hydrophobic substitution was shown to have a very minor effect on the particle size. Dispersions with solids contents of up to 2% were obtained. Furthermore, the mechanical properties of the nanoparticles were investigated with force microscopy, and it was shown by fluorescence correlation spectroscopy that a fluorescent dye could be encapsulated in the nanoparticles by the applied nanoprecipitation procedure. PMID:23777243

Aschenbrenner, Eugen; Bley, Karina; Koynov, Kaloian; Makowski, Marcin; Kappl, Michael; Landfester, Katharina; Weiss, Clemens K

2013-07-02

359

Ferrite synthesis in microstructured media: Template effects and magnetic properties  

Microsoft Academic Search

Inverse micelles and organogels provide novel environments to synthesize ferrite particles. The fluid microstructure provides a template for the synthesis. Our experiments with ferrite synthesis in inverse micelles indicate the formation of superparamagnetic nanoparticles. Of interest is the encapsulation of these particles in polymer microspheres. The encapsulation is done using simple polymer precipitation in the micellar nonsolvent. The process results

C. J. O'Connor; Y. S. L. Buisson; S. Li; S. Banerjee; R. Premchandran; T. Baumgartner; V. T. John; G. L. McPherson; J. A. Akkara; D. L. Kaplan

1997-01-01

360

The preparation and characterization of folate-conjugated human serum albumin magnetic cisplatin nanoparticles?  

PubMed Central

Objective Nanoparticles are becoming an important method of targeted drug delivery. To evaluate the importance of folate-conjugated human serum albumin (HSA) magnetic nanoparticles (Folate-CDDP/HSA MNP), we prepared drug-loaded Folate-CDDP/HSA MNPs and characterized their features. Methods First, folate was conjugated with HSA under the effect of a condensing agent, and the conjugating rate was evaluated by a colorimetric method using 2, 4, 6 - trinitrobenzene sulfonic acid. Second, under N2 gas, Fe3O4 magnetic nanomaterials were prepared and characterized by using transmission electron microscopy (TEM), SEM-EDS and X-ray diffraction (XRD). Finally, Folate-CDDP/HSA MNP was prepared by using a solvent evaporation technique. TEM was used to observe particle morphology. The particle size and distribution of the prepared complexes were determined by a Laser particle size analyzer. Drug loading volume and drug release were investigated by a high performance liquid chromatography method (HPLC) in vitro. Results We successfully prepared folate-conjugated HSA and its conjugating rate was 27.26 µg/mg. Under TEM, Fe3O4 magnetic nanoparticles were highly electron density and had an even size distribution in the range of 10-20 nm. It was confirmed by SEM-EDS and XRD that Fe3O4 magnetic nanoparticles had been successfully prepared. Under TEM, drug-loaded magnetic nanoparticles were observed, which had a round shape, similar uniform size and smooth surface. Their average size was 79 nm which was determined by laser scattering, and they exhibited magnetic responsiveness. Encapsulation efficiency was 89.75% and effective drug loading was calculated to be 15.25%. The release results in vitro showed that the half release time (t½) of cisplatin in cisplatin Solution and Folate-CDDP/HSA MNP was 65 min and 24 h respectively, which indicated that microspheres had an obvious effect of sustained-release. Conclusion Folate-CDDP/HSA MNPs were prepared successfully. The preparation process and related characteristics data provided a foundation for further study, including the mechanism of the nanoparticles distribution in vivo and their intake by tumor cells.

Chen, Daozhen; Tang, Qiusha; Xue, Wenqun; Xiang, Jingying; Zhang, Li; Wang, Xinru

2010-01-01

361

Characterization of ferrogels prepared using gamma-Fe2O3 and Fe3O4 nanoparticles  

Microsoft Academic Search

In this study, we compare the characteristics of ferrogels prepared using gamma-Fe2O3 and Fe3O4 nanoparticles. The magnetic nanoparticles with ~ 20 nm diameter were distributed in N-isopropylacrylamide (NIPAM) gel prepared using N,N'-methylenebisacrylamide (BIS), ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). Particle distribution and agglomeration characteristics of the prepared ferrogels were investigated using ultra small angle x-ray scattering (USAXS) and transmission electron

Kamlesh J. Suthar; Muralidhar K. Ghantasala; Derrick C. Mancini; Jan Ilavsky

2009-01-01

362

Preparation, physicochemical characterization, and antioxidant effects of quercetin nanoparticles.  

PubMed

The purpose of this study was to develop quercetin-loaded nanoparticles (QUEN) by a nanoprecipitation technique with Eudragit E (EE) and polyvinyl alcohol (PVA) as carriers, and to evaluate the antioxidant effects of quercetin (QU) and of its nanoparticles. The novel QUEN systems were characterized by particle size and morphology, yield and encapsulation efficiency, differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), (1)H nuclear magnetic resonance ((1)H NMR), and dissolution study. It was observed that the weight ratio of QU:EE:PVA at 1:10:10 carried a particle size of <85 nm, a particle distribution with polydispersity index <0.3, and its yield and encapsulation efficiency were over 99%. The results from XRD and DSC of the QUEN showed that the crystal of the drug might be converted to an amorphous state. The FT-IR and (1)H NMR demonstrated that QU formed intermolecular hydrogen bonding with carriers. The release of the drug from the QUEN was 74-fold higher compared with the pure drug. In addition, the antioxidant activity of the QUEN was more effective than pure QU on DPPH scavenging, anti-superoxide formation, superoxide anion scavenging, and anti-lipid peroxidation. PMID:17689897

Wu, Tzu-Hui; Yen, Feng-Lin; Lin, Liang-Tzung; Tsai, Tong-Rong; Lin, Chun-Ching; Cham, Thau-Ming

2007-06-28

363

Microbial preparation of metal-substituted magnetite nanoparticles  

SciTech Connect

A microbial process that exploits the ability of iron-reducing microorganisms to produce copious amounts of extra-cellular metal (M)-substituted magnetite nanoparticles using akaganeite and dopants of dissolved form has previously been reported. The objectives of this study were to develop methods for producing M-substituted magnetite nanoparticles with a high rate of metal substitution by biological processes and to identify factors affecting the production of nano crystals. The thermophilic and psychrotolerant iron-reducing bacteria had the ability to form M substituted magnetite nano-crystals (MyFe3-yO4) from a doped precursor, mixed-M iron oxyhydroxide, (MxFe1-xOOH, x 0.5, M is Mn, Zn, Ni, Co, and Cr). Within the range of 0.01 x 0.3, using the mixed precursor material enabled the microbial synthesis of more heavily substituted magnetite compared to the previous method, in which the precursor was pure akaganeite and the dopants were present as soluble metal salts. The mixed precursor method was especially advantageous in the case of toxic metals such as Cr and Ni. Also this new method increased the production rate and magnetic properties of the product, while improving crystallinity, size control and scalability.

Moon, Ji Won [ORNL; Roh, Yul [Chonnam National University, Gwangju; Lauf, Robert J [ORNL; Vali, Hojatollah [McGill University, Montreal, Quebec; Yeary, Lucas W [ORNL; Phelps, Tommy Joe [ORNL

2007-01-01

364

Self-assembly and embedding of nanoparticles by in situ reduced graphene for preparation of a 3D graphene/nanoparticle aerogel.  

PubMed

A 3D graphene architecture can be prepared via an in situ self-assembly of graphene prepared by a mild chemical reduction. Fe(3) O(4) nanoparticles are homogeneously dispersed into graphene oxide (GO) aqueous suspension and a 3D magnetic graphene/Fe(3) O(4) aerogel is prepared during the reduction of GO to graphene. This provides a general method to prepare 3D graphene/nanoparticle composites for a wide range of applications including catalysis and energy conversion. PMID:22052602

Chen, Wufeng; Li, Sirong; Chen, Chunhua; Yan, Lifeng

2011-11-04

365

Influence of initial particle size on the magnetostriction of sintered cobalt ferrite derived from nanocrystalline powders  

NASA Astrophysics Data System (ADS)

The role of initial particle size on the magnetostriction coefficient of sintered cobalt ferrite derived from nanocrystalline powders is studied. Nanoparticles of cobalt ferrite with different sizes in the range 3-80 nm are synthesized by an autocombustion method using metal nitrates and glycine. It has been observed that the initial particle size of the starting powders has a strong influence on the magnetostrictive behavior of sintered cobalt ferrite. Highest magnetostrictive strain and strain derivative are obtained for sintered ferrite derived from nanoparticles of size < 5 nm. The results show that higher magnetostriction coefficient for sintered cobalt ferrite can be achieved by compacting nanocrystalline particles of very small size.

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

2013-11-01

366

Preparation of Y2O3:Eu3+ nanoparticles in reverse micellar systems and their photoluminescence properties.  

PubMed

Y2O3:Eu3+ phosphor nanoparticles (4-8 nm in size) with spherical morphology and narrow size distribution were obtained by calcination of composite Y-Eu hydroxide nanoparticles, which were prepared in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/isooctane or polyethylene glycol mono-4-nonylphenyl ether (NP-5)/cyclohexane reverse micellar systems. This was achieved by the incorporation of the Y-Eu hydroxide nanoparticles into polyurea (PUA) via in situ polymerization of hexamethylene diisocyanate (HDI) in the reverse micellar solution and subsequent calcination of the resulting PUA materials. The emission intensity of the Y2O3:Eu3+ nanoparticles, prepared in the AOT/isooctane system, was significantly lower than that of the micrometer-size particles prepared in a homogeneous aqueous solution, since the calcined nanoparticles contained Na2SO4 impurity derived from the remaining AOT surfactant. The nanoparticles prepared in the NP-5/cyclohexane system, in contrast, showed higher emission intensity compared to the nanoparticles prepared in the AOT/isooctane system and longer luminescence lifetime compared to the micrometer-size particles prepared in the homogeneous aqueous solution. The photoluminescence intensity of Y2O3:Eu3+, prepared via the proposed process was found to decrease with decreasing the particle size. PMID:15271561

Hirai, Takayuki; Asada, Yoko; Komasawa, Isao

2004-08-15

367

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

PubMed Central

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.

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

368

Preparation and characterization of smart polymer brush-modified magnetic nanoparticles for biomedicine application  

Microsoft Academic Search

This paper investigates synthesis and characterization of smart polymer brush-modified magnetic nanoparticles (SPB-MNPs).\\u000a Magnetic nanoparticles (MNPs) modified with poly(poly(ethylene glycol) monomethacrylate (poly(PEGMA)) brush were first functioned\\u000a with activated pyridyldithio. Then, MNPs functioned with pyridyldithio (MNPs-PEG-PDT) were conjugated with 4-diamino-6-mercaptopyrimidine\\u000a (DMP) to form SPB-MNPs via stimuli-responsive disulfide linkage. Fourier transform infrared spectra (FTIR) was used to monitor\\u000a the preparation process of

Shixing Wang; Yang Zhou; Wen Guan; Bingjun Ding

2009-01-01

369

[Preparation and antibacterial capacity of artificial skin loaded with nanoparticles silver using bacterial cellulose].  

PubMed

In the present paper, in-situ preparation of silver nanoparticles have been conducted in 3D network structure of BC membrane through liquid phase chemical deoxidization method. The characterization of products was investigated using scanning electron microscopy (SEM), infrared spectroscopy (IR), energy dispersion spectrometry (SEM-EDS). The absorbing water capacity and preserving water capacity of substitutes and the antibacterial capacities of antibacterial agent-loaded artificial skin were tested. The results showed the silver nanoparticles were approximately spherical particles with an average diameter of 45nm, and were noted to have excellent sterilizing efficacy the efficiency of against Escherichia coli, yeast and Candida albicans. PMID:19947484

Sun, Dongping; Yang, Jiazhi; Li, Jun; Zhou, Lingli; Yu, Junwei

2009-10-01

370

A simple way to prepare Cupric oleate capped AgI nanoparticles  

SciTech Connect

Cupric oleate capped AgI (Cu(OA){sub 2}-AgI) nanoparticles were prepared by a simple method and they have good dispersibility in organic solvents. X-ray diffraction (XRD), transmission electron microscope (TEM), FTIR, X-ray photoelectron spectrometer (XPS) and ultraviolet-visible (UV-vis) spectrometer were used to characterize the Cu(OA){sub 2}-AgI nanoparticles. The results show that the mean size is about 80 nm; the modified reagent has been chemically bonded on the surface of AgI. In addition, new absorption peaks in the UV region appear.

Song Meirong [Laboratory of Special Functional Materials, Henan University, Kaifeng 475001 (China); Zhang Zhijun [Laboratory of Special Functional Materials, Henan University, Kaifeng 475001 (China)]. E-mail: s234soow@henu.edu.cn

2004-12-02

371

A facile water-based process for preparation of stabilized Bi nanoparticles  

SciTech Connect

Stabilized bismuth nanoparticles have been prepared by reducing bismuth chloride with hydrazine hydrate in the presence of sodium oleate under a facile water-based process. The obtained samples are investigated by X-ray diffraction, transmission electron microscopy (TEM) and differential thermal analysis and thermogravimetry (DTA/TG). The present results indicate that the bismuth nanoparticles are spherical, small diameter and in a high purity. In addition, measurement of water contact angle indicates that Bi samples are hydrophobic, which gives defense to samples from further oxidation, samples are steady in 6 months without obvious oxidation.

Wang Yi [College of Chemistry, Jilin University, Changchun 130023 (China); Department of Chemistry, Yanbian University, Yanji 133000 (China); Zhao Jingzhe [Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)], E-mail: zhaojz@mail.jlu.edu.cn; Zhao Xu; Tang Lanqin; Li Yunling; Wang Zichen [College of Chemistry, Jilin University, Changchun 130023 (China)

2009-01-08

372

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

PubMed

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

Tankhiwale, Rasika; Bajpai, S K

2011-09-22

373

Water-repellent coatings prepared by modification of ZnO nanoparticles.  

PubMed

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

Chakradhar, R P S; Dinesh Kumar, V

2012-04-02

374

Ferritic steel melt and FLiBe\\/steel experiment : melting ferritic steel  

Microsoft Academic Search

In preparation for developing a Z-pinch IFE power plant, the interaction of ferritic steel with the coolant, FLiBe, must be explored. Sandia National Laboratories Fusion Technology Department was asked to drop molten ferritic steel and FLiBe in a vacuum system and determine the gas byproducts and ability to recycle the steel. We tried various methods of resistive heating of ferritic

Kenneth P. Troncosa; Brandon M. Smith; Tina Joan Tanaka

2004-01-01

375

Preparation and magnetic properties of spindle porous iron nanoparticles  

SciTech Connect

Spindle porous iron nanoparticles were firstly synthesized by reducing the pre-synthesized hematite ({alpha}-Fe{sub 2}O{sub 3}) spindle particles with hydrogen gas. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption isotherms and vibrating sample magnetometry (VSM). A lattice shrinkage mechanism was employed to explain the formation process of the porous structure, and the adsorbed phosphate was proposed as a protective shell in the reduction process. N{sub 2} adsorption/desorption result showed a Brunauer-Emmett-Teller (BET) surface area of 29.7 m{sup 2}/g and a continuous pore size distribution from 2 nm to 100 nm. The magnetic hysteresis loop of the synthesized iron particles showed a saturation magnetization of 84.65 emu/g and a coercivity of 442.36 Oe at room temperature.

Lv Baoliang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Yao [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Wu Dong; Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Number 27, Tao Yuan South Road, Taiyuan, Shanxi 030001 (China)

2009-05-06

376

Preparation of AlFe nanoparticles by mechanical alloyed technique.  

PubMed

Small metallic particles (1-3 nm) have been obtained using mechanical alloying techniques. Analytical techniques such as scanning electron microscopy have been used for the morphological and chemical characterization of the AlFe alloyed powders. B, Ni and Ti have been explored as reinforced elements to the initial AlFe mixture. X-ray diffraction patterns and transmission electron microscopy (TEM) techniques have been employed for the structural characterization of the small metallic particles. Theoretical simulations based on molecular dynamics have been used to interpret some of the experimental structural results. Furthermore, theoretical simulations of HREM images based on the dynamical theory of electron diffraction have also been obtained and comparisons with the experimental results have been carried out. The complementary analyses determined that the produced clusters are basically AlFe alloyed nanoparticles immersed in a matrix and with multiple defected structures. PMID:16430152

Rosas, G; Esparza, R; Liu, H B; Ascencio, J A; Pérez, R

2005-12-01

377

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

Microsoft Academic Search

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

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

2007-01-01

378

Preparation and application of MS-M 2+ nanoparticles as a novel resonance light-scattering probe  

Microsoft Academic Search

Metal-enriched metal sulfide nanoparticles (MS-M2+, M=Zn, Cu, Pb, Ni, Cd) have been prepared. We found ZnS-Zn2+ and CuS-Cu2+ nanoparticles are water-soluble and biocompatible. They could be used as new kind of resonance light-scattering (RLS) probes in the determination of gamma-globulin human, which was proved to be a simple, rapid and specific method. In comparison with organic dye probes, these nanoparticles

Lun Wang; Fagong Xu; Yunyou Zhou; Leyu Wang; Yunchun Liu

2004-01-01

379

Preparation and Structure of FeNi nanoparticles coated with Ag and its Microwave-Absorption Properties  

Microsoft Academic Search

Microwave-absorption materials that have a good magnetic permeability and electrical conductivity are attracting more attentions in the EMI shielding field. This manuscript reported a kind of microwave-absorption FeNi@Ag nanoparticles fabricated through silver mirror reaction, i.e. silver was coated onto the surface of FeNi nanoparticles. The results showed that monodisperse spherical FeNi@Ag nanoparticles had been successfully prepared and exhibited ferromagnetic behavior

Shaofeng Zhou; Qiaoxin Zhang; Jingsong Zhou; Guojin Shen; Jin Huang

2012-01-01

380

Preparation of Carvedilol Nanoparticles by Emulsification Method and Optimization of Drug Release: Surface Response Design vs Genetic Algorithm  

Microsoft Academic Search

The objectives of this research were production of Eudragit nanoparticles of carvedilol the anti-hypertension drug for enhancement its absorption and optimization of drug release. Nanoparticles were prepared by emulsification-solvent evaporation or diffusion methods. The statistical surface response design based on Box-Behnken model was applied to evaluate the effect of 4 variables each in 2 levels on specifications of nanoparticles. An

Jaleh Varshosaz; Elaheh Moazen; Milad Fathi

2012-01-01

381

Preparation and heat transfer properties of nanoparticle-in-transformer oil dispersions as advanced energy-efficient coolants  

Microsoft Academic Search

Three kinds of nanofluids are prepared by dispersing Al2O3 and AlN nanoparticles-in-transformer oil. The thermal conductivity of the nanoparticle–oil mixtures increases with particle volume fraction and thermal conductivity of the solid particle itself. The AlN nanoparticles at a volume fraction of 0.5% can increase the thermal conductivity of the transformer oil by 8% and the overall heat transfer coefficient by

C. Choi; H. S. Yoo; J. M. Oh

2008-01-01

382

Preparation of NiO nanoparticles and their catalytic activity in the thermal decomposition of ammonium perchlorate  

Microsoft Academic Search

NiO nanoparticles with an average size of 10nm were prepared by a solid-state reaction using nickel acetate and sodium hydroxide as the raw materials and the Tween 80 as dispersant. The reaction was studied by DTA, TG, XRD and FTIR. The size and morphology of NiO nanoparticles were characterized by TEM. The catalytic effect of the NiO nanoparticles for thermal

Yanping Wang; Junwu Zhu; Xujie Yang; Lude Lu; Xin Wang

2005-01-01

383

Liquid antisolvent preparation of amorphous cefuroxime axetil nanoparticles in a tube-in-tube microchannel reactor.  

PubMed

This article presents the preparation of nanoparticles of amorphous cefuroxime axetil (CFA) in a microporous tube-in-tube microchannel reactor (MTMCR). The experimental results indicated that CFA particle with a tunable size of 400-1400 nm could be achieved under a high throughput in the range of 1.5-6L/min. The average particle size decreased with increasing overall volumetric flow rate and decreasing CFA concentration, micropore size, and annular channel width. The produced CFA nanoparticles were characterized by SEM, XRD, FT-IR, DSC and a dissolution test, which indicated that the nanosized CFA was amorphous and exhibited higher dissolution rate compared to the raw CFA. The MTMCR might offer a general and facile pathway for mass production of the nanoparticles of hydrophobic pharmaceuticals thanks to its high throughput capacity and excellent micromixing performance. PMID:20493936

Zhu, Wen-Zhen; Wang, Jie-Xin; Shao, Lei; Zhang, Hai-xia; Zhang, Qian-xia; Chen, Jian-Feng

2010-05-21

384

Preparation of tungsten carbide nanoparticles by ion implantation and electrochemical etching  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

385

Zinc incorporation capacity of whey protein nanoparticles prepared with desolvation with ethanol.  

PubMed

Whey protein isolate (WPI) nanoparticles were prepared using ethanol desolvation, and their capacity to incorporate ZnCl(2) was analysed. Desolvation was carried out at pH 9 and the volume of added ethanol was 0-3 times the volume of protein solution. The desolvated solutions were dispersed in acidified water (pH 3) immediately after desolvation. The size of the WPI nanoparticles increased with the volume ratio of ethanol:water used, as well as with the amount of ZnCl(2). The nanoparticles showed high incorporation efficiencies, and remained stable after 30 days of storage at 22 °C. The amount of zinc incorporated in the WPI particle suspensions was within the range of daily zinc requirements for healthy adults. PMID:22868157

Gülseren, ?brahim; Fang, Yuan; Corredig, Milena

2012-05-11

386

Ultrasonic cavitation induced water in vegetable oil emulsion droplets--a simple and easy technique to synthesize manganese zinc ferrite nanocrystals with improved magnetization.  

PubMed

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

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

2011-11-07

387

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

PubMed

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

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

2013-06-20

388

Preparation of magnetic nanoparticles for magnetic fluid hyperthermia  

Microsoft Academic Search

In this paper, the determination and preparation of suitable magnetic material for magnetic fluid hyperthermia (MFH) is presented. It was suggested that the highest heating rate could be obtained by using maghemite with particle diameter of 15 nm. The heating rate of magnetite particle with diameter less than 10 nm was found to generate heat higher than that of cobalt

T. Atsumi; B. Jeyadevan; Y. Sato; K. Tamura; S. Aiba; K. Tohji

2005-01-01

389

Preparation of monodisperse polyelectrolyte complex nanoparticles in dilute aqueous solution  

Microsoft Academic Search

Polyelectrolyte complexes (PEC) have been obtained by a fast ionic exchange reaction between polyelectrolytes bearing oppositely charged groups. Depending on the nature of the polyelectrolyte components and the mixing conditions, highly aggregated PECs with no phase separation during complexation can be prepared. PEC formation in diluted solutions and at non-stoichiometric mixing ratios results in homogeneous systems of sphere-like particles with

Heide-Marie Buchhammer; Mandy Mende; Marina Oelmann

390

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

PubMed Central

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

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

391

Preparation, characterization, and in vivo evaluation of tanshinone IIA solid dispersions with silica nanoparticles  

PubMed Central

We prepared solid dispersions (SDs) of tanshinone IIA (TSIIA) with silica nanoparticles, which function as dispersing carriers, using a spray-drying method and evaluated their in vitro dissolution and in vivo performance. The extent of TSIIA dissolution in the silica nanoparticles/TSIIA system (weight ratio, 5:1) was approximately 92% higher than that of the pure drug after 60 minutes. However, increasing the content of silica nanoparticles from 5:1 to 7:1 in this system did not significantly increase the rate or extent of TSIIA dissolution. The physicochemical properties of SDs were investigated using scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction, and Fourier transforms infrared spectroscopy. Studying the stability of the SDs of TSIIA revealed that the drug content of the formulation and dissolution behavior was unchanged under the applied storage conditions. In vivo tests showed that SDs of the silica nanoparticles/TSIIA had a significantly larger area under the concentration-time curve, which was 1.27 times more than that of TSIIA (P < 0.01). Additionally, the values of maximum plasma concentration and the time to reach maximum plasma concentration of the SDs were higher than those of TSIIA and the physical mixing system. Based on these results, we conclude that the silica nanoparticle based SDs achieved complete dissolution, increased absorption rate, maintained drug stability, and showed improved oral bioavailability compared to TSIIA alone.

Jiang, Yan-rong; Zhang, Zhen-hai; Liu, Qi-yuan; Hu, Shao-ying; Chen, Xiao-yun; Jia, Xiao-bin

2013-01-01

392

Preparation and characterization of TiO2-cationic hybrid nanoparticles as electrophoretic particles  

NASA Astrophysics Data System (ADS)

The hybrid nanoparticles (TiO2-HNPs) with TiO2 nanoparticles as core and with poly(N,N-dimethylaminoethyl methacrylate-co-methyl methacrylate) by using triallylamine as cross-linking agent as shell were firstly prepared via atom transfer radical polymerization (ATRP) in methanol. Then the hybrid nanoparticles with positive charge were produced by the quaternization with methyl iodide as quaternization reagent so as to endow them with greater electrophoretic mobility. The cationic hybrid nanoparticles (TiO2-CHNPs) were studied by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) measurements. The results indicate that the cationic polymer is successfully grafted on the surface of the TiO2 nanoparticles. The particle size of TiO2-CHNPs is about 150 nm and the polydispersity index (PDI) is 0.307. The zeta potential, the contrast ratio of white state to dark state and response time of TiO2-CHNPs are +16.8 mV, 30 and 3 s, respectively, which show the potential application prospect in the development of electrophoretic ink.

Li, Jingjing; Deng, Liandong; Xing, Jinfeng; Dong, Anjie; Li, Xianggao

2012-01-01

393

Preparation and catalytic properties of platinum dioxide nanoparticles: A comparison between conventional heating and microwave-assisted method  

Microsoft Academic Search

Using platinum chloride, sodium hydroxide, sodium acetate, and polyvinylpyrrolidone as starting materials, platinum dioxide nanoparticles with small particle diameter and narrow distribution were prepared by microwave irradiation and conventional heating, respectively. UV–vis spectrophotometer was used to trace the hydrolytic decomposition of platinum chloride and the formation of platinum dioxide nanoparticles. X-ray powder diffraction and transmission electron microscopy were employed to

Rongjun Pan; Yucheng Wu; Qingping Wang; Yu Hong

2009-01-01

394

Preparation, Characterization and in vitro Toxicity Test of Magnetic Nanoparticle-Based Drug Delivery System to Hyperthermia of Biological Tissues  

Microsoft Academic Search

The goals of this study were first to prepare and second to test albumin-based beads containing maghemite nanoparticles dispersed on them. Incorporation of maghemite nanoparticles in the albumin-based template, allowing full control of the magnetic content, was accomplished by adding ionic magnetic fluid to the albumin suspension, following heat denaturation. The material evaluation was performed using Zeta potential measurements and

Andreza Ribeiro Simioni; Fernando Lucas Primo; Marcilene Machado Andrade Rodrigues; Zulmira Guerrero Marques Lacava; Paulo Cesar Morais; Antonio Claudio Tedesco

2007-01-01

395

Effect of trastuzumab-modified antisense oligonucleotide-loaded human serum albumin nanoparticles prepared by heat denaturation  

Microsoft Academic Search

Nanoparticles represent a promising tool for targeted drug delivery to tumour cells and are able to protect drugs against degradation. In our present study we developed targeted nanoparticles loaded with antisense oligonucleotides (ASOs) against Plk1 (polo-like kinase 1) prepared by heat denaturation instead of using glutaraldehyde. Glutaraldehyde can lead to an inactivation of ASOs through chemical crosslinking and is a

Isabel M. Steinhauser; Klaus Langer; Klaus M. Strebhardt; Birgit Spänkuch

2008-01-01

396

Inverse magnetocaloric effect in sol-gel derived nanosized cobalt ferrite  

Microsoft Academic Search

The magnetocaloric properties of cobalt ferrite nanoparticles were investigated to evaluate the potential of these materials as magnetic refrigerants. Nanosized cobalt ferrites were synthesized by the method of sol-gel combustion. The nanoparticles were found to be spherical with an average crystallite size of 14 nm. The magnetic entropy change (Delta S m) calculated indirectly from magnetization isotherms in the temperature

E. Veena Gopalan; I. A. Al-Omari; D. Sakthi Kumar; Yasuhiko Yoshida; P. A. Joy; M. R. Anantharaman

2010-01-01

397

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

SciTech Connect

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.

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

398

Bismuth ferrite (BiFeO 3) nanopowder prepared by sucrose-assisted combustion method: A novel and reusable heterogeneous catalyst for acetylation of amines, alcohols and phenols under solvent-free conditions  

Microsoft Academic Search

Bismuth ferrite (BiFeO3) nanopowder was prepared by the novel combustion technique using sucrose as a fuel. The catalyst was characterized by using XRD, FT-IR, scanning electron microscope (SEM), transmission electron microscope (TEM), and BET surface area measurement and used as the heterogeneous catalyst for the acetylation reaction under solvent-free conditions. Efficient and selective acetylation of various amines, alcohols and phenols

Saeid Farhadi; Masoumeh Zaidi

2009-01-01

399

Enhancing encapsulation efficiency of highly water-soluble antibiotic in poly(lactic-co-glycolic acid) nanoparticles: Modifications of standard nanoparticle preparation methods  

Microsoft Academic Search

Effective encapsulations of drugs that are highly soluble in both water and organic solvents are notoriously difficult to achieve using standard nanoparticle preparation methods, such as nanoprecipitation (NPC), single (ESE), and double (DESE) emulsification-solvent-evaporation methods. Modifications of the standard preparation methods are therefore needed to enhance encapsulation efficiency of this group of drugs. The present work investigates the feasibility of

Wean Sin Cheow; Kunn Hadinoto

2010-01-01

400

Effect of various formulation parameters on the properties of polymeric nanoparticles prepared by multiple emulsion method.  

PubMed

This work evaluates and interprets underlying mechanisms behind various aspects related to preparation and physical characteristics of polymeric nanoparticles (NP). These were prepared from different biodegradable polymers according to a water-in-oil-in-water emulsion solvent evaporation method. Polymers used were poly(lactic-co-glycolic) acid (PLGA), poly (lactic acid) (PLA), (PLA-PEG-PLA) triblock and (PLA-PEG-PLA)n multi-block co-polymers. A model DNA, as an example of a hydrophilic drug, was encapsulated in the internal aqueous phase. The primary emulsion was prepared using a high shear turbine mixer. The secondary emulsion was prepared by high-pressure homogenization. Surface morphology and internal structure were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Influence of process variables on the physical properties of NP has been studied. Release of DNA was evaluated. In addition, changes occurring to NP porosity and surface area during degradation were followed. Nanoparticle size was ranging between 200-700 nm, according to the preparation conditions. Homogenizing pressure, concentration of the emulsifying agent used, polymer concentration and type and the concentration of a cryoprotectant had variable effects on NP size, surface area and porosity. Batches of NP where no emulsifying agent was added were obtained successfully. The release rate of the DNA from NP was mainly dependent on porosity, which varied significantly among used polymers. The preparation technique was efficient in encapsulating the model DNA and will be used for plasmid encapsulation in a future work. PMID:16830976

Rizkalla, Nevine; Range, Charlotte; Lacasse, François-Xavier; Hildgen, Patrice

2006-02-01

401

Structural, Magnetic and Mössbauer evaluation of Mn substituted Co-Zn ferrite nanoparticles synthesized by co-precipitation  

NASA Astrophysics Data System (ADS)

X-ray and Mössbauer studies have been made on Co0.5-xMnxZn0.5Fe2O4 prepared by the co-precipitation method from stoichiometric aqueous solutions. In these compositions x varies from 0.0to 0.5in steps of 0.1. The as-synthesized powders were characterized by the X-ray diffraction analysis (XRD), transmission electron microscopy, Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and Mössbauer spectroscopy at room temperature. The XRD results revealed the production of a broad single cubic phase with the average crystallite size of about 5-8 nm. The FTIR measurements between 400 and 4000 cm-1 confirmed the intrinsic cation vibrations of the spinel structure. The Mössbauer spectral studies showed that the substitution of magnetic Mn2+ is responsible for the increase in the intensity of the central paramagnetic doublet. The VSM results showed that as the Mn content increases up to 0.4the Curie point, the coercivity and saturation magnetization decrease.

Sharifi, Ibrahim; Shokrollahi, H.

2013-05-01

402

Preparation and photocatalytic properties of silver nanoparticles loaded on CNTs/TiO 2 composite  

NASA Astrophysics Data System (ADS)

In this study, new nanoscale photocatalyst based on silver and CNTs/TiO 2 was successfully prepared by photoreduction method. The prepared Ag-CNTs/TiO 2 was characterized by TEM, XRD and XPS. The photocatalytic activity was also evaluated by photocatalytic degradation of Reactive Brilliant Red X-3B dye. The results indicated that the photocatalytic efficiency of CNTs/TiO 2 increased in the presence of Ag nanoparticles and the photocatalysis reaction followed a first order kinetics. The kinetic constant of Ag-CNTs/TiO 2 for dye degradation was nearly 1.2 times than that of CNTs/TiO 2, which indicated decorating Ag nanoparticles on CNTs/TiO 2 could enhance the photocatalytic ability.

Wang, Shuo; Gong, Qianming; Zhu, Yuefeng; Liang, Ji

2009-06-01

403

Facile preparation of silver nanoparticle films as an efficient surface-enhanced Raman scattering substrate  

NASA Astrophysics Data System (ADS)

Here, we report a new and facile method to prepare silver nanoparticles (Ag NPs) film for surface-enhanced Raman scattering (SERS)-based sensing. The porous Ni foam was used as a template to generate high quality of Ag NPs by seed-mediated growth of metallic nanoparticles. The preparation process is very economic and environment-friendly, can achieve the recovery of the raw materials. We found that the type of silver-plating solution and the growth time are two key factors to determine the magnitude of SERS signal enhancement. Using rhodamine 6G (R6G) and 4-animothiophenol (4-ATP) as probe molecules, the created Ag NP films exhibited relatively high enhancement ability, good stability, and well reproducibility. The synthesized SERS-active substrate was further used to detect melamine molecules, an illegal additive in infant milk powder, and the limitation of detection can reach 1 ?M.

Sun, Yujing; Zhang, Yue; Shi, Yan; Xiao, Xianping; Dai, Haichao; Hu, Jingting; Ni, Pengjuan; Li, Zhuang

2013-10-01

404

Chirality control for in situ preparation of gold nanoparticle superstructures directed by a coordinatable organogelator.  

PubMed

Imposing chirality into nanoscale superstructures is a major step forward toward systematic understanding and utilization of nanomaterials. In an attempt to achieve tunable chirality during in situ preparation of hybrid nanomaterials, we here report a novel unimolecular strategy of employing a coordinatable organogelator for the realization of chirality control in the formation of gold nanoparticle superstructures. The work takes advantage of thermally reversible sol-gel transition of the chiral dispersion as template, which causes different micelle properties that can influence the coordination ability between the organogelator and Au(III) ions. Followed by a reduction reaction, gold nanoparticle superstructures with P-helicity were prepared from the sol form of the template through a coordination-induced chiral inversion, whereas those with M-helicity were obtained from the gel form with chiral holding. Such superstructures are solvent-stable and the chirality difference between them could be observed in many solvent environments. PMID:23705828

Zhu, Liangliang; Li, Xin; Wu, Shaojue; Nguyen, Kim Truc; Yan, Hong; Ågren, Hans; Zhao, Yanli

2013-06-04

405

Preparation of chitosan-based nanoparticles for delivery of low molecular weight heparin.  

PubMed

The chitosan nanoparticles (CSNPs) loading with low molecular weight heparin (LMWH) was prepared by ionic gelatin process of chitosan (CS) and sodium tripolyphosphate (TPP) and the preparation process was optimized by a central composite design (CCD). Encapsulation efficiency (96.98%), loading efficiency (30.76%), average diameter (814 nm) and zeta potential (+0.86 mV) were achieved for the optimal nanoparticle (NP) formulation, and the release behavior of drug from CSNPs in vitro fitted Weibull kinetics model. The relative bioavailability of oral administration in rats of LMWH loaded CSNPs to LMWH solution was 517%. The results showed that CCD may well predict desired in vitro characterization of LMWH CSNPs, and CSNPs can significantly enhance the oral absorption of LMWH in rats. PMID:22195488

Wang, Juan; Tan, Haining; Yu, Aihua; Ling, Peixue; Lou, Hongxiang; Zhai, Guangxi; Wu, Jun

2011-10-01

406

Preparation of carbon nanotubes supported platinum nanoparticles by an organic colloidal process for nonenzymatic glucose sensing  

Microsoft Academic Search

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

Li-Hua Li; Wei-De Zhang

2008-01-01

407

Preparation and Physicochemical Characterization of Aqueous Dispersions of Coenzyme Q 10 Nanoparticles  

Microsoft Academic Search

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

Britta Siekmann; Kirsten Westesen

1995-01-01

408

A simple technique for preparing carbon encapsulated La and Eu nanoparticles  

Microsoft Academic Search

A simple and efficient method for preparing graphitic carbon encapsulated rare-earth metal (lanthanum and europium) nanoparticles was explored. The samples were obtained by carbonizing a mixture of soluble metallic salt and dextrose at 773K, and subsequently annealing the mixture at 1273K in a nitrogen atmosphere. The annealed samples were studied by X-ray diffraction, high-resolution transmission electron microscopy, laser particle-size analysis

Hong Cao; Ru Li; Jun Xue; Hongli Li; Xuehua Wang; Xiaobei Bin; Shucun Chen; Houkui Xiang

2009-01-01

409

Preparation of a novel fluorescence nanoparticles and its application in the determination of Hg(II)  

Microsoft Academic Search

The strong fluorescence 2-vinylnaphthalene and acrylic acid polymer nanoparticles have been prepared under ultrasonic radiation. Based on the fluorescence quenching of polymer by Hg(II), a method for the selective determination of Hg(II) was developed. The reaction conditions between Hg(II) and polymer were investigated in detail. The assay is very few interference stable fluorescence signals (at least 2h), simple instrument (common

Lun Wang; Ling Dong; Gui-Rong Bian; Ting-Ting Xia

2005-01-01

410

A novel terbium composite nanoparticles: Preparation and selective fluorescence determination of chromium(VI)  

Microsoft Academic Search

A highly efficient ultrasonic-assisted method was successfully applied to prepare the strong fluorescence Tb\\/acetyl acetone (acac)\\/poly (2-Acrylamidoglycolic acid monohydrate) (PAAM) composite nanoparticles. Based on the fluorescence quenching of Tb\\/acac\\/PAAM by Cr(VI), an assay for the selective determination of Cr(VI), without separation of Cr(III), was developed. It is characteristic of very few interferences, stable fluorescence signals (at least 2h), simple instrument

Lun Wang; Binbin Qian; Hongqi Chen; Yan Liu; Ani Liang

2008-01-01

411

Characterization and applications of as-grown ?-Fe 2 O 3 nanoparticles prepared by hydrothermal method  

Microsoft Academic Search

The production of low-dimensional nanoparticles (NPs) with appropriate surface modification has attracted increasing attention\\u000a in biological, biochemical, and environmental applications including chemical sensing, photocatalytic degradation, separation,\\u000a and purification of toxic molecules from the matrices. In this study, iron oxide NPs have been prepared by hydrothermal method\\u000a using ferric chloride and urea in aqueous medium under alkaline condition (pH 9 ~ 10). As-grown

Mohammed M. Rahman; Aslam Jamal; Sher Bahadar Khan; Mohd Faisal

412

Preparation of acicular ?-Fe nanoparticles in a lamellar liquid crystalline phase  

Microsoft Academic Search

Acicular ?-Fe nanoparticles were prepared by sodium borohydride reduction of ferrous chloride in the presence of the liquid crystalline system, C12EO4\\/water. The shape of the acicular particles was templated by the colloid and a magnetic field. The acicular particles obtained from the lamellar phase were 50~150 nanometers long and 5 nanometers wide. The product also included some spherical particles of

Jianping Chen; David E. Nikles

1996-01-01

413

Ultrafine FePt Nanoparticles Prepared by the Chemical Reduction Method  

Microsoft Academic Search

Monodisperse FePt nanoparticles with particle size of about 2 nm have been prepared by 1,2-hexadecanediol reduction of iron acetylacetonate and platinum acetylacetonate in dioctyl ether. The as-synthesized particles have a chemically disordered fcc structure and can be transformed into chemically ordered fct structure after thermal processing at temperatures above 500°C. The ordered fct FePt phase has high magnetic anisotropy and

Kevin E. Elkins; Tejaswi S. Vedantam; J. P. Liu; Hao Zeng; Shouheng Sun; Y. Ding; Z. L. Wang

2003-01-01

414

Preparation of cells for assessing ultrastructural localization of nanoparticles with transmission electron microscopy  

Microsoft Academic Search

We describe the use of transmission electron microscopy (TEM) for cellular ultrastructural examination of nanoparticle (NP)-exposed biomaterials. Preparation and imaging of electron-transparent thin cell sections with TEM provides excellent spatial resolution (?1 nm), which is required to track these elusive materials. This protocol provides a step-by-step method for the mass-basis dosing of cultured cells with NPs, and the process of

Amanda M Schrand; John J Schlager; Liming Dai; Saber M Hussain

2010-01-01

415

The preparation and characterization of La doped TiO 2 nanoparticles and their photocatalytic activity  

Microsoft Academic Search

In this paper, pure and La doped TiO2 nanoparticles with different La content were prepared by a sol–gel process using Ti (OC4H9)4 as raw material, and also were characterized by XRD, TG-DTA, TEM, XPS, DRS and Photoluminescence (PL) spectra. We mainly investigated the effects of calcining temperature and La content on the properties and the photocatalytic activity for degrading phenol

Jing Liqiang; Sun Xiaojun; Xin Baifu; Wang Baiqi; Cai Weimin; Fu Honggang

2004-01-01

416

Preparation and characterization of (3-aminopropyl)triethoxysilane-coated magnetite nanoparticles  

Microsoft Academic Search

Magnetite nanoparticles coated with (3-aminopropyl)triethoxysilane, NH2(CH2)3Si(OC2H5)3, were prepared by silanization reaction and characterized by X-ray diffractometry, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy and magnetization measurements. Both uncoated and organosilane-coated magnetite exhibited superparamagnetic behavior and strong magnetization at room temperature. Basic groups anchored on the external surface of the coated magnetite were observed. The superparamagnetic particles of

M Yamaura; R. L Camilo; L. C Sampaio; M. A Macêdo; M Nakamura; H. E Toma

2004-01-01

417

Preparation and characterization of silica coated iron oxide magnetic nano-particles  

Microsoft Academic Search

Iron oxide magnetic nano-particles have been prepared by precipitation in an aqueous solution of iron(II) and iron(III) chlorides under basic condition. Surface modifications have been carried out by using tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS). The uncoated and coated particles have been characterized with transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, thermal gravimetric analysis (TGA), and infrared (IR) and

Ying-Sing Li; Jeffrey S. Church; Andrea L. Woodhead; Filsun Moussa

2010-01-01

418

The effect of liquid environment on size and aggregation of gold nanoparticles prepared by pulsed laser ablation  

Microsoft Academic Search

The effects of liquid environment on nucleation, growth and aggregation of gold nanoparticles were studied. Gold nanoparticles\\u000a were prepared by pulsed laser ablation in deionised water with various concentrations of ethanol and also in pure ethanol.\\u000a UV\\/visible extinction and TEM observations were employed for characterization of optical properties and particle sizes respectively.\\u000a Preparation in water results in smaller size, shorter

R. M. Tilaki; A. Iraji zad; S. M. Mahdavi

2007-01-01

419

NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS  

SciTech Connect

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.

Seetala V. Naidu; Upali Siriwardane; Akundi N. Murty

2004-02-23

420

A novel method for synthesizing PEGylated chitosan nanoparticles: strategy, preparation, and in vitro analysis.  

PubMed

Preparation of poly (ethylene glycol) (PEG)-grafted chitosan is essential for improving the biocompatibility and water solubility of chitosan. Presently available methods for this have limitations. This article describes a new method for preparing PEGylated chitosan nanoparticles. For this chitosan was chemoselectively modified using a novel scheme at the C6 position of its repeating units by PEG. The amine groups at the C2 position of the chitosan were protected using phthalic anhydride. Sodium hydride was used to catalyze the etherification reaction between chlorinated chitosan and methyl-PEG, and PEG-grafted chitosan was successfully synthesized. Each step was characterized using 13C nuclear magnetic resonance and Fourier transform infrared. After PEGylation the phthaloylated chitosan was successfully deprotected using hydrazine monohydrate. The synthetic scheme proposed demonstrates a new method for grafting PEG onto chitosan with a moderate degree of substitution. The potential of this polymer in nanoparticle preparation using an ionic gelation method and its gene delivery potentials were investigated by complexing a fluorescently labeled control siRNA. The result showed that suitable nanoparticles can be synthesized using this polymer and that they have capacity to carry genes and provide adequate transfection efficacy with no toxicity when tested in neuronal cells. PMID:21562608

Malhotra, Meenakshi; Lane, Ciaran; Tomaro-Duchesneau, Catherine; Saha, Shyamali; Prakash, Satya

2011-03-03

421

Preparation of platinum nanoparticle and its catalytic activity for toluene oxidation.  

PubMed

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

Kim, Sang Chai; Shim, Wang Geun; Lee, Man Seung; Jung, Sang Chul; Park, Young-Kwon

2011-08-01

422

Preparation of polymer core–shell particles supporting gold nanoparticles  

Microsoft Academic Search

The organic\\/inorganic composites were fabricated by catalytic reduction of tetrachloroaurate ions in poly[2-(N,N-dimethylamino)ethyl methacrylate] shell layers on polystyrene core particles. The core–shell particles were prepared by emulsifier-free emulsion polymerization of styrene (St) with 2-chloropropionyloxyethyl methacrylate (CPEM) using potassium persulfate as an initiator, followed by surface-initiated activator generated electron transfer-atom transfer radical polymerization (AGET-ATRP) of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) on core particles

Tatsuo Taniguchi; Takumi Inada; Takuya Kashiwakura; Fumiyasu Murakami; Michinari Kohri; Takayuki Nakahira

2011-01-01

423

Solution-combusting preparation of mono-dispersed Mn3O4 nanoparticles for electrochemical applications  

NASA Astrophysics Data System (ADS)

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.

Gao, Weiwei; Ye, Shiyong; Shao, Mingwang

2011-09-01

424

Preparation, Characterization and Evaluation of Targeting Potential of Amphotericin B-Loaded Engineered PLGA Nanoparticles  

Microsoft Academic Search

Purpose  The objective of present work was to develop a mannose-anchored, engineered nanoparticulate system for efficient delivery\\u000a of amphotericin B to macrophages. Furthermore, the effect of spacer on macrophage targeting was also evaluated.\\u000a \\u000a \\u000a \\u000a Methods  PLGA was conjugated to mannose via direct coupling (M-PLGA) and via PEG spacer (M-PEG-PLGA), and engineered PLGA nanoparticles\\u000a (M-PNPs and M-PEG-PNPs) were prepared from respective conjugates. These prepared

Manoj Nahar; Narendra K. Jain

2009-01-01

425

Preparation of BMP2 Containing Bovine Serum Albumin (BSA) Nanoparticles Stabilized by Polymer Coating  

Microsoft Academic Search

Purpose  The purpose of this study was to investigate the preparation process of bone morphogenetic protein-2 (BMP-2) containing bovine\\u000a serum albumin (BSA) nanoparticles (NPs), and to assess the bioactivity of BMP-2 encapsulated in such NPs.\\u000a \\u000a \\u000a \\u000a Methods  The NPs were prepared by a coacervation method, and the effects of process parameters on NP size and polydispersity were examined.\\u000a Polymer coated NPs were characterized

Guilin Wang; Kevin Siggers; Sufeng Zhang; Hongxing Jiang; Zhenghe Xu; Ronald F. Zernicke; John Matyas; Hasan Uluda?

2008-01-01

426

A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe3O4 and CdS nanoparticles  

NASA Astrophysics Data System (ADS)

Preparation of novel magneto-fluorescence polystyrene microsphere containing Fe3O4 and CdS nanoparticles by hydrothermal decomposition of cadmium O,O?-diethyl dithiophosphate in water on the polystyrene microspheres supported Fe3O4 nanoparticles.

Kaboudin, Babak; Ghaderian, Abolfazl

2013-10-01

427

Recyclable nano-size Pd catalyst generated in the multilayer polyelectrolyte films on the magnetic nanoparticle core  

Microsoft Academic Search

This work describes the preparation of Pd nanoparticles in multilayer polyelectrolyte films fabricated on a magnetic ferrite core by a layer-by-layer (LbL) self-assembly technique, and the relationship between catalytic activity and these hybrid core-shell nanocomposite structures in the hydrogenation of olefinic alcohols. The hydrogenation reaction seems to be only catalyzed by Pd nanoparticles in the outermost layer of the hybrid

Yuhong Wang; Jin-Kyu Lee

2007-01-01

428

Rapid preparation of pH-sensitive polymeric nanoparticle with high loading capacity using electrospray for oral drug delivery.  

PubMed

Drug loading capacity is an important property for an ideal drug delivery system. However, the drug loading capacity of prepared pH-sensitive polymeric nanoparticles is usually low. To overcome this drawback, the electrospray method was used to prepare Eudragit L 100-55 nanoparticles with high drug loading capacity in one step. Omeprazole was selected as the model drug. The maximum loading capacity of nanoparticles was 43.21% by changing the mass ratio of drug to polymer, and the entrapment efficiency was nearly 100%. The prepared nanoparticle showed spherical or ellipsoidal morphology and the average diameter was about 300nm. The pH-sensitive nanoparticle displayed pH-dependent release in vitro. In addition, a slight cytotoxicity was detected in the cytotoxicity study. The results indicated that electrospray is an easy, rapid and efficient technique for the preparation of high-loading pH-sensitive polymeric nanoparticles, and the pH-sensitive nanoparticle is a promising carrier for oral drug delivery. PMID:24094160

Hao, Shilei; Wang, Yazhou; Wang, Bochu; Deng, Jia; Liu, Xi; Liu, Junyu

2013-07-18

429

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

PubMed

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

Du, Zhuo; Liu, Miao; Li, Gongke

2013-09-01

430

Orthogonal optimization design for preparation of Fe3O4 nanoparticles via chemical coprecipitation  

NASA Astrophysics Data System (ADS)

Fe3O4 nanoparticles ranging from 8.9 to 12.2 nm were prepared by chemical coprecipitation based on L16(45) orthogonal experiments. The effects of five process parameters (pH, Fe2+/Fe3+ ratio, reaction temperature, ferric salt concentration, and crystallization temperature) on particle size and specific saturation magnetization of Fe3O4 nanoparticles were investigated. The micro-morphology, crystal structure, specific saturation magnetization, and surface properties were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), vibration magnetometer (VSM), and Fourier infrared (FT-IR). The results indicate that Fe2+/Fe3+ ratio and pH are the main factors affecting particle size and specific saturation magnetization, respectively. The Fe3O4 nanoparticles are mostly spherical powders with a narrow size distribution and a high purity. The Fe3O4 nanoparticles can achieve high dispersion performance and suspension stability by in situ dispersion with double adsorption layers.

Meng, Haining; Zhang, Zhenzhong; Zhao, Fangxia; Qiu, Tai; Yang, Jingdong

2013-09-01

431

Preparation and characterization novel polymer-coated magnetic nanoparticles as carriers for doxorubicin.  

PubMed

The poly(lactide-co-glycolide)-coated magnetic nanoparticles (PLGA MNPs) were prepared as carriers of doxorubicin (PLGA-DOX MNPs) through water-in-oil-in-water (W/O/W) emulsification method. The characteristics of PLGA-DOX MNPs were measured by using transmission electron microscopy (TEM) and vibrating-sampling magnetometry (VSM). It was found that the synthesized nanoparticles were spherical in shape with an average size of 100±20 nm, low aggregation and good magnetic responsivity. Meanwhile, the drug content and encapsulation efficiency of nanoparticles can be achieved by varying the feed weight ratios of PLGA and DOX particles. These PLGA-DOX MNPs also demonstrated sustained release of DOX at 37°C in buffer solution. Besides, influence of drug-loaded nanoparticles on in vitro cytotoxicity was determined by MTT assay, while cellular apoptosis was detected by Annexin V-FITC apoptosis detection kit. The results showed that PLGA-DOX MNPs retained significant antitumor activities. Therefore, PLGA-DOX MNPs might be considered a promising drug delivery system for cancer chemotherapy. PMID:21764271

Li, Fang; Sun, Jing; Zhu, Huaishi; Wen, Xuejun; Lin, Chao; Shi, Donglu

2011-06-25

432

Magnetic fluid based on Fe3O4 nanoparticles: Preparation and hyperthermia application  

NASA Astrophysics Data System (ADS)

The paper presents results of research on preparing the magnetic fluid based on Fe3O4 nanoparticles and its potential hyperthermia application. Magnetic fluids were manufactured by dissolving superparamagnetic nanoparticles coated by suitable biocompatible starch layer during the co-precipitation processing. The coated particle size changes in range of 15÷17 nm were characterized by FESEM images. At room temperature, the samples exhibit super-paramagnetic behaviour with a saturation moment of 65 emu/g. The concentration of magnetic nanoparticles contained in carried liquid reach to 15 mg/ml. The magnetic fluid was used as a mediator for heating by an AC magnetic field with the frequency of 184 kHz and field strength of 12 kA/m. The dependence of heating on nanoparticle concentration was observed and it implied that the magnetic fluid is a suitable mediator for cancer treatment by hyperthermia application with appropriate controlling the heating temperature ranges from 45 to 50°C.

Hoai Linh, Pham; Van Thach, Pham; Tuan, Nguyen Anh; Thuan, Nguyen Chi; Manh, Do Hung; Phuc, Nguyen Xuan; Van Hong, Le

2009-09-01

433

Magnetic Properties of FePt Nanoparticles Prepared by a Micellar Method  

NASA Astrophysics Data System (ADS)

FePt nanoparticles with average size of 9 nm were synthesized using a diblock polymer micellar method combined with plasma treatment. To prevent from oxidation under ambient conditions, immediately after plasma treatment, the FePt nanoparticle arrays were in situ transferred into the film-growth chamber where they were covered by an SiO2 overlayer. A nearly complete transformation of L10 FePt was achieved for samples annealed at temperatures above 700 °C. The well control on the FePt stoichiometry and avoidance from surface oxidation largely enhanced the coercivity, and a value as high as 10 kOe was obtained in this study. An evaluation of magnetic interactions was made using the so-called isothermal remanence (IRM) and dc-demagnetization (DCD) remanence curves and Kelly-Henkel plots (? M measurement). The ? M measurement reveals that the resultant FePt nanoparticles exhibit a rather weak interparticle dipolar coupling, and the absence of interparticle exchange interaction suggests no significant particle agglomeration occurred during the post-annealing. Additionally, a slight parallel magnetic anisotropy was also observed. The results indicate the micellar method has a high potential in preparing FePt nanoparticle arrays used for ultrahigh density recording media.

Gao, Y.; Zhang, X. W.; Yin, Z. G.; Qu, S.; You, J. B.; Chen, N. F.

2010-01-01

434

Controllable preparation of nanoparticles by drops and plugs flow in a microchannel device.  

PubMed

Well controlled two-liquid-phase flows in a T-junction microchannel device have been realized. The system of H2SO4 and BaCl2, respectively, in two phases to form BaSO4 nanoparticles was used as a probe to characterize the microscale two-phase flow and transport conditions of a system with interphase mass transfer and chemical reaction. Nanoparticles with narrow size and good dispersibility were produced through drops or plugs flow in the microdevice. As a novel work, the influence of mass transfer and chemical reaction on interfacial tension and flow patterns was discussed based on the experiments. At the same time, the effect of the two-phase flow patterns on the nanoparticle size was also discussed. It was found that the increase of the amount of mass transfer and chemical reaction could change the flow patterns from plugs flow to drops flow. The drop diameter or plug length could be changed in a wide range. Accordingly, a new parameter of mu(0)u(c)/gamma(0)/Q(d) was defined to distinguish the flow patterns. The prepared nanoparticles ranged in size from 10 to 40 nm. Apparently, the particle size decreased with the increase of the drop diameter or plug length. Reasons were discussed based on the mass transfer direction and speed in drops and plugs flow patterns. PMID:18335970

Li, Shaowei; Xu, Jianhong; Wang, Yujun; Luo, Guangsheng

2008-03-12

435

Preparation and characterization of metformin hydrochloride loaded-Eudragit®RSPO and Eudragit®RSPO/PLGA nanoparticles.  

PubMed

The aim of the present study was to develop and characterize metformin HCl-loaded nanoparticle formulations. Nanoparticles were prepared by the nanoprecipitation method using both a single polymer (Eudragit(®)RSPO) and a polymer mixture (Eudragit/PLGA). The mean particle size ranged from 268.8 to 288 nm and the nanoparticle surface was positively charged (9.72 to 10.1 mV). The highest encapsulation efficiency was observed when Eudragit®RSPO was used. All formulations showed highly reproducible drug release profiles and the in vitro drug release in phosphate buffer (pH = 6.8) ranged from 92 to 100% in 12 h. These results suggest that Eudragit(®)RSPO or Eudragit/PLGA nanoparticles might represent a promising sustained-release oral formulation for metformin HCl, reducing the necessity of repeated administrations of high doses to maintain effective plasma concentrations, and thus, increasing patient compliance and reducing the incidence of side-effects. PMID:21864098

Cetin, Meltem; Atila, Alptug; Sahin, Selma; Vural, Imran

2011-08-24

436

Investigation of structural and magnetic properties of nanocrystalline manganese substituted lithium ferrites  

SciTech Connect

Nanocrystalline manganese substituted lithium ferrites Li{sub 0.5}Fe{sub 2.5-x}Mn{sub x}O{sub 4} (2.5<=x>=0) were prepared by sol-gel auto-combustion method. X-ray diffraction patterns revealed that as the concentration of manganese increased, the cubic phase changed to tetragonal. Magnetic properties were measured by hysteresis loop tracer technique. All the compositions indicated ferrimagnetic nature. The surface morphology of all the samples was studied by using scanning and transmission electron microscopy. The substitution of manganese ions in the lattice affected the structural as well as magnetic properties of spinels. - Graphical abstract: The synthesized nanoparticles shapes, sizes and size dispersibilities were obtained from the transmission electron microscopy (TEM). The TEM micrographs of synthesized samples revealed that, spherical shape with average particle size 50 nm. Selected area electron diffraction pattern (SAED) suggests the polycrystallinity and also the formation of spinel ferrites.

Hankare, P.P., E-mail: p_hankarep@rediffmail.co [Department of Chemistry, Shivaji University, Kolhapur 416004, Maharashtra (India); Patil, R.P., E-mail: raj_rbm_raj@yahoo.co.i [Department of Chemistry, Shivaji University, Kolhapur 416004, Maharashtra (India); Sankpal, U.B.; Jadhav, S.D. [Department of Chemistry, Shivaji University, Kolhapur 416004, Maharashtra (India); Lokhande, P.D. [Pune University, Pune, Maharashtra, India. (India); Jadhav, K.M. [Dr. B.A.Marathwada University, Aurangabad 431004, Maharashtra (India); Sasikala, R. [Chemistry Division, Bhabha Atomic Research Center, Mumbai 400085, Maharashtra (India)

2009-12-15

437

Functionalized lipid nanoparticles-cellophane hybrid films for molecular delivery: preparation, physicochemical characterization, and stability.  

PubMed

Lipid nanoparticles functionalized with the sunscreen 2,4-dihydroxybenzophenone (FLNPs) have been prepared by the ultrasound method and embedded in highly hydrophilic cellophane supports (regenerated cellulose, RC), creating biocompatible hybrid films (RC-FLNPs samples). The morphology of the FLNPs was studied with transmission microscopy, whereas the surface and interior chemical composition was analyzed by micro-Raman spectroscopy. RC-FLNPs hybrid films were prepared from the immersion of two cellophane supports with different thicknesses and water uptake properties (RC-3 and RC-6) in an aqueous dispersion of FLNPs. The structure of this hybrid material was visualized with bright-field microscopy, which clearly showed the inclusion of the FLNPs in the cellophane matrix. The stability of the RC-FLNPs films with respect to both aqueous environments and time was demonstrated by NaCl diffusion measurements. The reduction in the diffusion coefficient through the nanoparticle-modified films compared with the original supports confirms the presence of nanoparticles for concentration gradients of up to 0.4 M (osmotic pressure around 10 bar), indicating the stability of the hybrid hydrophilic material, even in aqueous environments and under matter flow conditions for a period of 21 days. PMID:21713774

Vázquez, M Isabel; Peláez, Laura; Benavente, Juana; López-Romero, J Manuel; Rico, Rodrigo; Hierrezuelo, Jesus; Guillén, Elena; López-Ramírez, M Rosa

2011-06-28

438

Preparation, in vitro release, and pharmacokinetics in rabbits of lyophilized injection of sorafenib solid lipid nanoparticles.  

PubMed

Sorafenib solid lipid nanoparticles (S-SLN) were prepared by emulsion evaporation-solidification at low temperature. Morphology was examined by transmission electron microscope. Particle size and zeta potential were determined by laser granularity equipment. Encapsulation efficiency (EE) was detected by Sephadex gel chromatography and high-performance liquid chromatography (HPLC). The in vitro release profile of S-SLN was studied with dialysis technology. The lyophilized injection of S-SLN was prepared by freeze drying and analyzed by differential scanning calorimetry. The plasma concentration of sorafenib in blood was determined by HPLC. The solid lipid nanoparticles assumed a spherical shape with an even distribution of diameter and particle size 108.23 ± 7.01 nm (n = 3). The polydispersity index, zeta potential, and EE were determined to be 0.25 ± 0.02, -16.37 ± 0.65 mV, and 93.49% ± 1.87%, respectively (n = 3). The in vitro release accorded with the Weibull distribution model. An equal volume of 15% (w/v) mannitol performed better as the protective agent for a lyophilized injection of S-SLN with a new material phase formation. The pharmacokinetic processes of sorafenib solution and lyophilized injection of S-SLN in vivo were in accordance with the two-compartment and one-compartment models, respectively. S-SLN nanoparticles are thus considered a promising drug-delivery system. PMID:22787390

Zhang, Hong; Zhang, Fu-Ming; Yan, Shi-Jun

2012-06-18

439

Preparation of enzyme nanoparticles and studying the catalytic activity of the immobilized nanoparticles on polyethylene films.  

PubMed

Using high-intensity ultrasound, in situ generated ?-amylase nanoparticles (NPs) were immobilized on polyethylene (PE) films. The ?-amylase NP-coated PE films have been characterized by E-SEM, FTIR, DLS, XPS and RBS. The PE was reacted with HNO(3) and NPs of the ?-amylase were also deposited on the activated PE. The PE impregnated with ?-amylase (4 ?g per 1mg PE) was used for hydrolyzing soluble potato starch to maltose. The immobilization improved the catalytic activity of ?-amylase at all the reaction conditions studied. The kinetic parameters, K(m) (5 and 4 g L(-1) for the regular and activated PE, respectively) and V(max) (5 × 10(-7) mol ml(-1) min(-1), almost the same numbers were obtained for the regular and activated PEs) for the immobilized amylase were found to slightly favor the respective values obtained for the free enzyme (K(m) = 6.6 g L(-1), V(max) = 3.7 × 10(-7) mol ml(-1) min(-1)). The enzyme remained bound to PE even after soaking the PE in a starch solution for 72 h and was still found to be weakly active. PMID:22800814

Meridor, David; Gedanken, Aharon

2012-06-29

440

Preparation and Characterization of Selenium Incorporated Guar Gum Nanoparticle and Its Interaction with H9c2 Cells  

PubMed Central

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.

Soumya, Rema Sreenivasan; Vineetha, Vadavanath Prabhakaran; Reshma, Premachandran Latha; Raghu, Kozhiparambil Gopalan

2013-01-01

441

Preparation and characterization of selenium incorporated guar gum nanoparticle and its interaction with h9c2 cells.  

PubMed

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

Soumya, Rema Sreenivasan; Vineetha, Vadavanath Prabhakaran; Reshma, Premachandran Latha; Raghu, Kozhiparambil Gopalan

2013-09-30

442

Preparation of gold nanoparticles by surfactant-promoted reductive reaction without extra reducing agent.  

PubMed

Cetyltrimethyl ammonium bromide (CTAB) has been extensively applied in the solution-phase synthesis of many types of colloidal nanoparticles. However, the uses of CTAB were mainly considered as template or capping agents to form controllable shape and protect the product from agglomeration. Here it was discovered that CATB could serve as a very mild reductant to reduce gold salt precursors preparing gold nanoparticles (GNPs) at base environment. CTAB acted as the reducing agent suffering a partial degradation and forming CTA macro radicals. FTIR proved the formation of CCl and/or CBr bond after CTAB degraded. The characterization of synthesized GNPs was examined by UV-Vis spectra, TEM and XRD. Several factors affecting the process of reaction, such as the amount of NaOH, the molar ratio of CTAB and HAuCl(4), the reaction temperature, the effect of light and oxygen, and stirring were discussed. PMID:23261633

Tang, Junqi; Huang, Jiamin; Man, Shi-Qing

2012-11-05

443

Preparation of iron oxides using ammonium iron citrate precursor: Thin films and nanoparticles  

NASA Astrophysics Data System (ADS)

Ammonium iron citrate (C6H8O7·nFe·nH3N) was used as a precursor for preparing both iron-oxide thin films and nanoparticles. Thin films of iron oxides were fabricated on silicon (111) substrate using a successive-ionic-layer-adsorption-and-reaction (SILAR) method and subsequent hydrothermal or furnace annealing. Atomic force microscopy (AFM) images of the iron-oxide films obtained under various annealing conditions show the changes of the micro-scale surface structures and the magnetic properties. Homogenous Fe3O4 nanoparticles around 4 nm in diameter were synthesized by hydrothermal reduction method at low temperature and investigated using transmission electron microscopy (TEM).

Park, Sangmoon

2009-09-01

444

Redispersible drug nanoparticles prepared without dispersant by electro-spray drying.  

PubMed

The redispersibility of drug nanoparticles is critical in the formulation development of oral solid dosage forms from drug nanosuspensions. To address this issue, various drying techniques such as, spray drying, fluidized bed drying, etc. have been developed based on freeze drying. In this work, redispersible dried powders were successfully prepared from drug nanosuspensions without the use of dispersant by applying an electrical potential to the nozzle during the spray drying process. The applied voltage, not the concentration of the nanosuspension, was critical in determining the redispersibility. Despite the high electric field, the particle morphology and crystallinity were not dependent on the applied voltage, which suggests that the drug crystals were not damaged. This novel technique could broaden the applicability of spray drying technology and allow for novel formulations of drug nanoparticles. PMID:22010908

Ho, Hwanki; Lee, Jonghwi

2011-10-19

445

Preparation of bifunctional mesoporous silica nanoparticles by orthogonal click reactions and their application in cooperative catalysis.  

PubMed

The synthesis of bifunctional mesoporous silica nanoparticles is described. Two chemically orthogonal functionalities are incorporated into mesoporous silica by co-condensation of tetraethoxysilane with two orthogonally functionalized triethoxyalkylsilanes. Post-functionalization is achieved by orthogonal surface chemistry. A thiol-ene reaction, Cu-catalyzed 1,3-dipolar alkyne/azide cycloaddition, and a radical nitroxide exchange reaction are used as orthogonal processes to install two functionalities at the surface that differ in reactivity. Preparation of mesoporous silica nanoparticles bearing acidic and basic sites by this approach is discussed. Particles are analyzed by solid state NMR spectroscopy, elemental analysis, infrared-spectroscopy, and scanning electron microscopy. As a first application, these particles are successfully used as cooperative catalysts in the Henry reaction. PMID:23132649

Dickschat, Arne T; Behrends, Frederik; Bühner, Martin; Ren, Jinjun; Weiss, Mark; Eckert, Hellmut; Studer, Armido

2012-11-06

446