共查询到20条相似文献,搜索用时 906 毫秒
1.
Satoshi Seino Takuya Kinoshita Takashi Nakagawa Takao Kojima Ryoichi Taniguci Shuichi Okuda Takao A. Yamamoto 《Journal of nanoparticle research》2008,10(6):1071-1076
Composite nanoparticles consisting of gold and iron oxide were synthesized in aqueous solution systems by using a high-energy
electron beam. The electron irradiation induces radiation-chemical reaction to form metallic gold nanoparticles. These gold
nanoparticles were firmly immobilized on the surface of the support iron oxide nanoparticles. Surface of the support iron
oxide nanoparticles are almost fully coated with fine gold nanoparticles. The size of these gold nanoparticles depended on
the concentrations of gold ions, polymers and iron oxide nanoparticles in the solutions before the irradiation. 相似文献
2.
Zhanhu Guo Koo Shin Amar B. Karki David P. Young Richard B. Kaner H. Thomas Hahn 《Journal of nanoparticle research》2009,11(6):1441-1452
The effect of iron oxide nanoparticle addition on the physicochemical properties of the polypyrrole (PPy) was investigated.
In the presence of iron oxide nanoparticles, PPy was observed in the form of discrete nanoparticles, not the usual network
structure. PPy showed crystalline structure in the nanocomposites and pure PPy formed without iron oxide nanoparticles. PPy
exhibited amorphous structure and nanoparticles were completely etched away in the nanocomposites formed with mechanical stirring
over a 7-h reaction. The thermal stability of the PPy in the nanocomposites was enhanced under the thermo-gravimetric analysis
(TGA). The electrical conductivity of the nanocomposites increased greatly upon the initial addition (20 wt%) of iron oxide
nanoparticles. However, a higher nanoparticle loading (50 wt%) decreased the conductivity as a result of the dominance of
the insulating iron oxide nanoparticles. Standard four-probe measurements indicated a three-dimensional variable-range-hopping
conductivity mechanism. The magnetic properties of the fabricated nanocomposites were dependent on the particle loading. Ultrasonic
stirring was observed to have a favorable effect on the protection of iron oxide nanoparticles from dissolution in acid. A
tight polymer structure surrounds the magnetic nanoparticles, as compared to a complete loss of the magnetic iron oxide nanoparticles
during conventional mechanical stirring for the micron-sized iron oxide particles filled PPy composite fabrication. 相似文献
3.
A novel method for fabricating magnetic iron oxide nanoparticles was achieved by using transparent vermicelli template as a new stabilizing material. The morphology of the as-prepared magnetic iron oxide deposited on the surface of vermicelli was observed as nanoclusters. The magnetization of the magnetic iron oxide nanoparticles at room temperature was decreased after carbonization at 200 °C. Therefore the thermal decomposition of iron oxide nanoparticles stabilized by starch vermicelli template yielded iron oxide/carbon nanocomposites with the soft magnetic behavior which are useful for biomedical applications. 相似文献
4.
Ilker Dincer Onur Tozkoparan Sergey V. German Alexey V. Markin Oguz Yildirim Gennady B. Khomutov Dmitry A. Gorin Sergey B. Venig Yalcin Elerman 《Journal of magnetism and magnetic materials》2012
Aqueous colloidal suspension of iron oxide nanoparticles has been synthesized. Z-potential of iron oxide nanoparticles stabilized by citric acid was −35±3 mV. Iron oxide nanoparticles have been characterized by the light scattering method and transmission electron microscopy. The polyelectrolyte/iron oxide nanoparticle thin films with different numbers of iron oxide nanoparticle layers have been prepared on the surface of silicon substrates via the layer-by-layer assembly technique. The physical properties and chemical composition of nanocomposite thin films have been studied by atomic force microscopy, magnetic force microscopy, magnetization measurements, Raman spectroscopy. Using the analysis of experimental data it was established, that the magnetic properties of nanocomposite films depended on the number of iron oxide nanoparticle layers, the size of iron oxide nanoparticle aggregates, the distance between aggregates, and the chemical composition of iron oxide nanoparticles embedded into the nanocomposite films. The magnetic permeability of nanocomposite coatings has been calculated. The magnetic permeability values depend on the number of iron oxide nanoparticle layers in nanocomposite film. 相似文献
5.
Dong Xi XiaoPing Luo QiangHua Lu KaiLun Yao ZuLi Liu Qin Ning 《Journal of nanoparticle research》2008,10(3):393-400
Gold-coated iron oxide nanoparticle Hepatitis B virus (HBV) DNA probes were prepared, and their application for HBV DNA measurement
was studied. Gold-coated iron oxide nanoparticles were prepared by the citrate reduction of tetra-chloroauric acid in the
presence of iron oxide nanoparticles which were added as seeds. With a fluorescence-based method, the maximal surface coverage
of hexaethiol 30-mer oligonucleotides and the maximal percentage of hybridization strands on gold-coated iron oxide nanoparticles
were (120 ± 8) oligonucleotides per nanoparticle, and (14 ± 2%), respectively, which were comparable with those of (132 ± 10)
and (22 ± 3%) in Au nanoparticle groups. Large network aggregates were formed when gold-coated iron oxide nanoparticle HBV
DNA gene probe was applied to detect HBV DNA molecules as evidenced by transmission electron microscopy and the high specificity
was verified by blot hybridization. Our results further suggested that detecting DNA with iron oxide nanoparticles and magnetic
separator was feasible and might be an alternative effective method. 相似文献
6.
Attila Lengyel Gyula Tolnai Zoltán Klencsár Vijayendra Kumar Garg Aderbal Carlos de Oliveira L. Herojit Singh Zoltán Homonnay Roland Szalay Péter Németh Bálint Szabolcs Mira Ristic Svetozar Music Ernő Kuzmann 《Journal of nanoparticle research》2018,20(5):137
57Fe Mössbauer spectroscopy, XRD, and TEM were used to investigate the effect of mandelic- and salicylic acid coatings on the iron oxide nanoparticles. These two carboxylic acids have similar molecules size and stoichiometry, but different structure and acidity. Significant differences were observed between the Mössbauer spectra of samples coated with mandelic acid and salicylic acid. These results indicate that the occurrence of iron microenvironments in the mandelic- and salicylic acid-coated iron oxide nanoparticles is different. The results can be interpreted in terms of the influence of the acidity of carboxylic acids on the formation, core/shell structure, and oxidation of coated iron oxide nanocomposites. 相似文献
7.
Alla Zablotskaya Izolda Segal Mikhail Maiorov Elmars Blums Ilona Domracheva 《Journal of magnetism and magnetic materials》2009,321(10):1428-1432
We present the results of the interaction of iron oxide nanoparticles with some biologically active surfactants, namely, oleic acid and cytotoxic alkanolamine derivatives. Physico-chemical properties, as magnetization, magnetite concentration and particle diameter, of the prepared magnetic samples were studied. The nanoparticle size of 11 nm for toluene magnetic fluid determined by TEM is in good agreement with the data obtained by the method of magnetogranulometry. In vitro cytotoxic effect of water-soluble nanoparticles with different iron oxide:oleic acid molar ratio were revealed against human fibrosarcoma and mouse hepatoma cells. In vivo results using a sarcoma mouse model showed observable antitumor action. 相似文献
8.
Lv Qing-yuan Li Xian-yi Shen Bao-de Dai Ling Xu He Shen Cheng-ying Yuan Hai-long Han Jin 《Journal of nanoparticle research》2014,16(6):1-14
Magnetic iron oxide nanoparticles surface covered with oleic acid layer followed by a second layer of hydrophobized oxidized dextran aldehyde were prepared and tested for physico-chemical properties and ligand- and cell-specific binding. It was demonstrated that oleic acid–iron oxide nanoparticles coated with an additional layer of hydrophobized oxidized dextran were dispersible in buffer solutions and possess surface aldehyde active groups available for further binding of ligands or markers via imine or amine bond formation. Hydrophobized dextrans were synthesized by periodate oxidation and conjugation of various alkanamines to oxidized dextran by imination. Physico-chemical properties, as separation using magnetic field, magnetite concentration, and particle diameter, of the prepared magnetic samples are reported. The biotin-binding protein, neutravidin, was coupled to the particle surface by a simple reductive amination procedure. The particles were used for specific cell separation with high specificity. 相似文献
9.
German Salazar-Alvarez Eva Björkman Cesar Lopes Anders Eriksson Sören Svensson Mamoun Muhammed 《Journal of nanoparticle research》2007,9(4):647-652
Microemulsions composed of normal or inverse micellar solutions and aqueous suspensions of pristine (uncoated) or silica-coated
iron oxide nanoparticles, mainly γ-Fe2O3, were synthesised and their optical limiting properties investigated. The microemulsions are colorless solutions with high
transparency for visible wavelengths while the aqueous suspensions of iron oxide are of pale yellow colour. Optical limiting
experiments performed in 2 mm cells using a f/5 optical system with a frequency doubled Nd:YAG laser delivering 5 ns pulses
with 10 Hz repetition rate, showed clamping levels of ∼3 μJ for the suspensions of both pristine and silica-coated iron oxide
nanoparticles. A strong photoinduced nonlinear light scattering was observed for the water-in-oil microemulsion and the aqueous
suspensions of nanoparticles while oil-in-water microemulsions did not show a significant nonlinear effect. Measurements carried
out using an integrating sphere further verified that the photoinduced nonlinear light scattering is the dominating nonlinear
mechanism while the nonlinear absorption of iron oxide nanoparticles is negligible at 532 nm. 相似文献
10.
Golla-Schindler U Hinrichs R Bomati-Miguel O Putnis A 《Micron (Oxford, England : 1993)》2006,37(5):473-477
The oxidation state of iron oxide nanoparticles was determined using the two principally different technical realisations of energy filtering TEM, in one case using the JEOL 3010 equipped with a LaB6 cathode and a post-column GIF and in the second, the newly designed LIBRA 200FE equipped with an corrected in-column 90 degrees energy filter and a field emission gun (Schottky emitter). The samples studied were oxide-coated iron nanoparticles, and iron oxide inclusions in feldspars in granites. Five possible candidates exist for the iron-oxide phases: FeO, alpha-Fe2O3 (hematite), gamma-Fe2O3 (maghemite), Fe3O4 (magnetite) or alpha-FeO(OH) (goethite). Fingerprinting the O K-edge ELNES allows to distinguish between oxide phases with the same stochiometry and enables to make a first selection of possible candidates. The additional determination of the chemical composition allows unique identification of the phase present. For the oxide coated iron nanoparticles the most probable iron oxide phase of the shell is maghemite, which was additionally confirmed by HRTEM studies. The second studied system were iron oxide needles in alkali feldspar, where we obtained hematite as the most probable phase. There we additionally demonstrated the drastic changes of the ELNES of the O K-edge for the alkali feldspar and iron oxide needle by spatially resolved EELS. 相似文献
11.
Iron oxide nanoparticles can exhibit highly tunable physicochemical properties that are extremely important in applications such as catalysis, biomedicine and environmental remediation. The small size of iron oxide nanoparticles can be used to stabilize oil-in-water Pickering emulsions due to their high energy of adsorption at the interface of oil droplets in water. The objective of this work is to investigate the effect of the primary particle characteristics and stabilizing agent chemistry on the stability of oil-in-water Pickering emulsions. Iron oxide nanoparticles were synthesized by the co-precipitation method using stoichiometric amounts of Fe2+ and Fe3+ salts. Sodium stearoyl lactylate (SSL), a Food and Drug Administration approved food additive, was used to functionalize the iron oxide nanoparticles. SSL is useful in the generation of fat-in-water emulsions due to its high hydrophilic–lipophilic balance and its bilayer-forming capacity. Generation of a monolayer or a bilayer coating on the nanoparticles was controlled through systematic changes in reagent concentrations. The coated particles were then characterized using various analytical techniques to determine their size, their crystal structure and surface functionalization. The capacity of these bilayer coated nanoparticles to stabilize oil-in-water emulsions under various salt concentrations and pH values was also systematically determined using various characterization techniques. This study successfully demonstrated the ability to synthesize iron oxide nanoparticles (20–40 nm) coated with SSL in order to generate stable Pickering emulsions that were pH-responsive and resistant to significant destabilization in a saline environment, thereby lending themselves to applications in advanced oil spill recovery and remediation. 相似文献
12.
Kyoungja Woo Jihyung Moon Kyu-Sil Choi Kwon-Ha Yoon 《Journal of magnetism and magnetic materials》2009,321(10):1610-1612
We prepared five folate-conjugated lipophilic superparamagnetic iron oxide nanoparticles (F5-Liposuperparamagnetic iron oxide nanoparticles(SPIONs), 5.5 and 11 nm) and investigated their cellular uptake with KB cells, which is one of the representative folate-receptor over-expressing human epidermoid carcinoma cells, using MRI. The cellular uptake tests with the respective 5.5 and 11 nm F5-LipoSPIONs at a fixed particle concentration showed appreciable amount of receptor-mediated uptakes and the specificity was higher in 5.5 nm SPIONs, due to its higher folic acid (FA) density, without inhibition. However, the numbers of the particles taken up under FA inhibition were similar, irrespective of their sizes. 相似文献
13.
Uniform iron oxide nanoparticles in the size range from 10 to 24 nm and polydisperse 14 nm iron oxide particles were prepared by thermal decomposition of Fe(III) carboxylates in the presence of oleic acid and co-precipitation of Fe(II) and Fe(III) chlorides by ammonium hydroxide followed by oxidation, respectively. While the first method produced hydrophobic oleic acid coated particles, the second one formed hydrophilic, but uncoated, nanoparticles. To make the iron oxide particles water dispersible and colloidally stable, their surface was modified with poly(ethylene glycol) and sucrose, respectively. Size and size distribution of the nanoparticles was determined by transmission electron microscopy, dynamic light scattering and X-ray diffraction. Surface of the PEG-functionalized and sucrose-modified iron oxide particles was characterized by Fourier transform infrared (FT-IR) and Raman spectroscopy and thermogravimetric analysis (TGA). Magnetic properties were measured by means of vibration sample magnetometry and specific absorption rate in alternating magnetic fields was determined calorimetrically. It was found, that larger ferrimagnetic particles showed higher heating performance than smaller superparamagnetic ones. In the transition range between superparamagnetism and ferrimagnetism, samples with a broader size distribution provided higher heating power than narrow size distributed particles of comparable mean size. Here presented particles showed promising properties for a possible application in magnetic hyperthermia. 相似文献
14.
Superparamagnetic iron oxide nanoparticles are used in diverse applications, including optical magnetic recording, catalysts,
gas sensors, targeted drug delivery, magnetic resonance imaging, and hyperthermic malignant cell therapy. Combustion synthesis
of nanoparticles has significant advantages, including improved nanoparticle property control and commercial production rate
capability with minimal post-processing. In the current study, superparamagnetic iron oxide nanoparticles were produced by
flame synthesis using a coflow flame. The effect of flame configuration (diffusion and inverse diffusion), flame temperature,
and additive loading on the final iron oxide nanoparticle morphology, elemental composition, and particle size were analyzed
by transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), energy dispersive spectroscopy (EDS), and Raman spectroscopy.
The synthesized nanoparticles were primarily composed of two well known forms of iron oxide, namely hematite αFe2O3 and magnetite Fe3O4. We found that the synthesized nanoparticles were smaller (6–12 nm) for an inverse diffusion flame as compared to a diffusion
flame configuration (50–60 nm) when CH4, O2, Ar, and N2 gas flow rates were kept constant. In order to investigate the effect of flame temperature, CH4, O2, Ar gas flow rates were kept constant, and N2 gas was added as a coolant to the system. TEM analysis of iron oxide nanoparticles synthesized using an inverse diffusion
flame configuration with N2 cooling demonstrated that particles no larger than 50–60 nm in diameter can be grown, indicating that nanoparticles did not
coalesce in the cooler flame. Raman spectroscopy showed that these nanoparticles were primarily magnetite, as opposed to the
primarily hematite nanoparticles produced in the hot flame configuration. In order to understand the effect of additive loading
on iron oxide nanoparticle morphology, an Ar stream carrying titanium-tetra-isopropoxide (TTIP) was flowed through the outer
annulus along with the CH4 in the inverse diffusion flame configuration. When particles were synthesized in the presence of the TTIP additive, larger
monodispersed individual particles (50–90 nm) were synthesized as observed by TEM. In this article, we show that iron oxide
nanoparticles of varied morphology, composition, and size can be synthesized and controlled by varying flame configuration,
flame temperature, and additive loading. 相似文献
15.
Yilian Fernández-Afonso Gorka Salas Irene Fernández-Barahona Fernando Herranz Cordula Grüttner Jesús Martínez de la Fuente María del Puerto Morales Lucía Gutiérrez 《Particle & Particle Systems Characterization》2020,37(7):2000032
Advanced uses of smartphones are changing lifestyles, and may have a great impact in materials science in the near future. In this work, the use of these devices to develop fast, simple, and cheap methods to characterize magnetic nanoparticle suspensions is tested. A series of dilutions of a wide library of magnetic nanoparticles, composed of iron oxide materials in the range between 3 and 43 nm, with two different shapes and four different coatings is prepared. The colloid color is analyzed using the RGB (red, green, blue) color model. Ratios of these parameters are correlated with the suspension iron concentration and with the nanoparticles average size. A linear relationship between the color (in particular the G/R ratio) and both the colloid iron content and the particles size is found. The link between these parameters allows the development of two new methods to determine either the concentration or the particle size of magnetic nanoparticle suspensions just by acquiring images from suspensions of iron oxide magnetic nanoparticles with a smartphone. 相似文献
16.
M.E. Saleta H.E. Troiani S. Ribeiro Guevara R.D. Snchez M. Malta R.M. Torresi 《Journal of magnetism and magnetic materials》2008,320(14):e268-e271
In this work, we present the synthesis and characterization of a hybrid nanocomposite constituted by iron oxide nanoparticles and vanadium oxide/Hexadecylamine (VOx/Hexa) nanotubes. Transmission Electron Microscopy (TEM) images show small particles (around 20 nm) in contact with the external wall of the multiwall tubes, which consist of alternate layers of VOx and Hexa. By Energy Dispersive Spectroscopy (EDS), we detected iron ions within the tube walls and we have also established that the nanoparticles are composed of segregated iron oxide. The samples were studied by Electron Paramagnetic Resonances (EPR) and dc-magnetization as a function of the magnetic field. The analysis of the magnetization and EPR data confirms that a fraction of the V atoms are in the V4+ electronic state and that the nanoparticles exhibit a superparamagnetic behavior. The percentage of V and Fe present in the nanocomposite was determined using Instrumental Neutron Activation Analysis (INAA). 相似文献
17.
Oscar Bomati-Miguel Nuria Miguel-Sancho Ibane Abasolo Ana Paula Candiota Alejandro G. Roca Milena Acosta Simó Schwartz Jr. Carles Arus Clara Marquina Gema Martinez Jesus Santamaria 《Journal of nanoparticle research》2014,16(3):1-13
Polyol synthesis is a promising method to obtain directly pharmaceutical grade colloidal dispersion of superparamagnetic iron oxide nanoparticles (SPIONs). Here, we study the biocompatibility and performance as T2-MRI contrast agents (CAs) of high quality magnetic colloidal dispersions (average hydrodynamic aggregate diameter of 16-27 nm) consisting of polyol-synthesized SPIONs (5 nm in mean particle size) coated with triethylene glycol (TEG) chains (TEG-SPIONs), which were subsequently functionalized to carboxyl-terminated meso-2-3-dimercaptosuccinic acid (DMSA) coated-iron oxide nanoparticles (DMSA-SPIONs). Standard MTT assays on HeLa, U87MG, and HepG2 cells revealed that colloidal dispersions of TEG-coated iron oxide nanoparticles did not induce any loss of cell viability after 3 days incubation with dose concentrations below 50 μg Fe/ml. However, after these nanoparticles were functionalized with DMSA molecules, an increase on their cytotoxicity was observed, so that particles bearing free terminal carboxyl groups on their surface were not cytotoxic only at low concentrations (<10 μg Fe/ml). Moreover, cell uptake assays on HeLa and U87MG and hemolysis tests have demonstrated that TEG-SPIONs and DMSA-SPIONs were well internalized by the cells and did not induce any adverse effect on the red blood cells at the tested concentrations. Finally, in vitro relaxivity measurements and post mortem MRI studies in mice indicated that both types of coated-iron oxide nanoparticles produced higher negative T2-MRI contrast enhancement than that measured for a similar commercial T2-MRI CAs consisting in dextran-coated ultra-small iron oxide nanoparticles (Ferumoxtran-10). In conclusion, the above attributes make both types of as synthesized coated-iron oxide nanoparticles, but especially DMSA-SPIONs, promising candidates as T2-MRI CAs for nanoparticle-enhanced MRI diagnosis applications. 相似文献
18.
Ernest Popovici Ion Morjan Victor Ciupina Ladislau Vekas Oana Marinica 《Applied Surface Science》2007,254(4):1048-1052
Well-dispersed nanoparticles with iron/iron carbide core and iron oxide shell structures may constitute an excellent magnetic material for different applications as magnetic nanofluids, contrast agents in magnetic resonance imaging, sensors and catalysts. Based on the ability of the CO2 laser pyrolysis technique to synthesize nanoparticles of the Fe/Fe2O3 core-shell type, we further improve the powder dispersion by first collecting the nanoparticles in a toluene bubbler, positioned downstream and prior to the collection filter. Structural characterisation of the samples by electron microscopy and X-ray diffraction was performed. Conditions in which clusters contain a reduced number of nanoparticles (around 50) are evidenced. Mean core-shell particle sizes of 15 nm were estimated. Finally, preliminary results on the morphology of iron/iron oxide core-shell nanoparticles as hydrocarbon-based magnetic nanofluids are presented. 相似文献
19.
Mingde Fan Peng Yuan Jianxi Zhu Aihua Yuan Kangmin Chen 《Journal of magnetism and magnetic materials》2009,321(20):3515-3519
Iron nanoparticles have been successfully synthesized using sodium borohydride solution reduction of ferric trichloride hexahydrate in the presence of montmorillonite as an effective protective reagent and support as well. A combination of characterizations reveals the well disperse of these obtained iron nanoparticles supported on the external surface of clay with roughly spherical morphology and mean diameter of 55 nm. The particles are oxidation resistant well with iron core-iron oxide shell structure. The shell thickness of 3 nm remains almost invariable under ambient conditions. Discernable hysteresis loop reveals ferromagnetic behavior of the iron nanoparticles, which make them easy for magnetic separation and potential in some practical applications. 相似文献
20.
G. A. Bukhtiyarova O. N. Mart’yanov S. S. Yakushkin M. A. Shuvaeva O. A. Bayukov 《Physics of the Solid State》2010,52(4):826-837
Physics of the Solid State - The state of iron in nanoparticles prepared by impregnating silica gel and aluminum oxide with iron(II) sulfate solutions has been investigated using Mössbauer... 相似文献