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Preparation and characterization of silica-coated Fe3O4 nanoparticles used as precursor of ferrofluids  

International Nuclear Information System (INIS)

Fe3O4 magnetic nanoparticles (MNPs) were synthesized by the co-precipitation of Fe3+ and Fe2+ with ammonium hydroxide. The sodium citrate-modified Fe3O4 MNPs were prepared under Ar protection and were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and vibrating sample magnetometer (VSM). To improve the oxidation resistance of Fe3O4 MNPs, a silica layer was coated onto the modified and unmodified MNPs by the hydrolysis of tetraethoxysilane (TEOS) at 50 deg. C and pH 9. Afterwards, the silica-coated Fe3O4 core/shell MNPs were modified by oleic acid (OA) and were tested by IR and VSM. IR results revealed that the OA was successfully grafted onto the silica shell. The Fe3O4/SiO2 core/shell MNPs modified by OA were used to prepare water-based ferrofluids (FFs) using PEG as the second layer of surfactants. The properties of FFs were characterized using a UV-vis spectrophotometer, a Gouy magnetic balance, a laser particle size analyzer and a Brookfield LVDV-III+ rheometer.

2009-01-01

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Preparation of Fe3O4/polystyrene composite particles from monolayer oleic acid modified Fe3O4 nanoparticles via miniemulsion polymerization  

International Nuclear Information System (INIS)

Fe3O4/polystyrene composite particles were prepared from oleic acid (OA) modified Fe3O4 nanoparticles via miniemulsion polymerization. It was concluded that the surface properties of OA modified magnetite nanoparticles have a great effect on preparation of the composite particles. When Fe3O4 nanoparticles coated by multilayer of OA was employed, there were large amounts of free polystyrene particles in the product. Fe3O4/polystyrene composite particles with defined structure and different magnetite content can be readily prepared from monolayer OA modified Fe3O4 nanoparticles. It was concluded that surface of the monolayer OA modified Fe3O4 nanoparticles is more hydrophobic than that of the multilayer coated ones, thus improving the dispersibility of the Fe3O4 nanoparticles in styrene monomer and allowing preparation of the Fe3O4/polystyrene composite particles with defined structure and controllable magnetite content.

2009-02-01

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Electrostatic Force Microscopy of Fe3O4 nanoparticles  

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The electronic compressibility is a fundamental property that characterizes the electronic properties of materials submitted to an external electric field. In metals (insulators), the electronic compressibility is large (small) and leads to a small (large) screening length. Variations of the screening length can be observed through measurements of the ``quantum'' capacitance between one material and a metallic counter-electrode. Using an Electrostatic Force Microscope (EFM), we measured maps of the local capacitance of 8 nm magnetite nanoparticles synthesized following the ``benzyl alcohol route'' deposited on a metallic substrate. Magnetite, an inverse spinel structure of composition Fe3O4, is a material with strongly correlated electronic properties and presents a metal-insulator transition at 120 K, the so-called Verwey transition. We present EFM measurements of these nanoparticles as a function of tip-sample distance and temperature.

Mottaghizadeh, A.; Lang, P. L.; Cui, L.; Lesueur, J.; Zimmers, A.; Aubin, H.; Li, J.; Zheng, D. N.; Rebuttini, V.; Pinna, N.

2012-02-01

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

Science.gov (United States)

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

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

2013-01-01

5

Magnetic anisotropy in Fe3O4-PVA nanocomposites as a result of Fe3O4-nanoparticles chains formation  

International Nuclear Information System (INIS)

To study the nature of anisotropy effects in samples of polymer (PVA) films containing nanoparticles of magnetite the depth selective conversion Moessbauer spectroscopy (for layer-by-layer phase and magnetic analysis), saturation isothermal remanent magnetization (SIRM) and natural remanent magnetization measurements (NRM) in three mutual-orthogonal directions and atomic force microscopy were used. These investigations revealed formation of 'in plane' direction of linear Fe3O4 nanoparticles chains and their number increase with nanoparticles concentration growth in the samples. Significant influence of polymer matrix on macroscopic magnetic properties was revealed from the temperature dependences of saturation magnetization and Moessbauer spectra

2006-05-01

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Size-controlled Synthesis and Characterization of Fe3O4 Nanoparticles by Chemical Coprecipitation Method  

International Nuclear Information System (INIS)

Magnetite (Fe3O4) nanoparticles have been synthesized using the chemical coprecipitation method. The Fe3O4 nanoparticles were likely formed via dissolution-recrystallization process. During the precipitation process, ferrihydrite and Fe(OH)2 particles formed aggregates and followed by the formation of spherical Fe3O4 particles. The synthesized Fe3O4 nanoparticles exhibited superparamagnetic behavior and in single crystal form. The synthesis temperature and the degree of agitation during the precipitation were found to be decisive in controlling the crystallite and particle size of the produced Fe3O4 nanoparticles. Lower temperature and higher degree of agitation were the favorable conditions for producing smaller particle. The magnetic properties (saturation magnetization and coercivity) of the Fe3O4 nanoparticles increased with the particle size. (author)

2008-12-01

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Synchrotron radiation photoelectron spectroscopy study of dextran-coated Fe3O4 magnetic nanoparticles  

International Nuclear Information System (INIS)

Dextran-coated Fe3O4 nanoparticles were prepared by untrasonification of Fe3O4 nanoparticles with dextran at 85 degree C in sodium citrate medium. The surface chemical component, structure and bond of uncoated and dextran-coated nanoparticles were measured by synchrotron radiation XPS(X-ray photoelectron spectroscopy). Qualitative and quantitative analysis of C1s and O1s of Fe3O4 and dextran-Fe3O4 showed that the Fe3O4 nanoparticles were successively coated by sodium citrate via Fe-O-C bond, and dextrans, which can be linked with their carboxylate moiety via hydrogen bond. Sodium citrate could enhance the disperse stability of reaction system and hydrophilicity of dextran-Fe3O4. (authors)

2009-04-01

8

Magnetic Nanoparticle Hyperthermia Using Pluronic-Coated Fe3O4 Nanoparticles: An In Vitro Study  

International Nuclear Information System (INIS)

Magnetic nanoparticles are promising materials for hyperthermia treatment. The temperature rise under ac magnetic field, cytotoxicity, and in vitro hyperthermia effect of Fe3O4 nanoparticles coated with Pluronic f-127 were evaluated in this paper. The Pluronic-coated Fe3O4 nanoparticles exhibited no cytotoxic effect on HeLa cells. The optimal magnetic field of Pluronic-coated Fe3O4 nanoparticles was 16 kA/m (200 Oe) at the field strength of 210 khz. Appropriate temperature rise significantly reduced the viability of HeLa cells and induced apoptosis.

2012-01-01

9

Biophysical interactions of polyamidoamine dendrimer coordinated Fe3O4 nanoparticles with insulin.  

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Advanced delivery systems, such as nano/micro carriers have not been studied significantly for their molecular interactions with serum proteins and other biologically relevant macromolecules. Here, we investigated the effect of surface chemistry of iron oxide (Fe3O4) nanoparticles on molecular interactions with human insulin by fluorescence, XRD and FTIR spectroscopy. Nanoparticles of Fe3O4 were chemically modified as Fe3O4-glutathione (GSH) and Fe3O4-GSH-polyamidoamine generation 4 (PAMAM G4) dendrimer. Our results demonstrate that, Fe3O4 and its conjugates such as Fe3O4-GSH, Fe3O4-GSH-G4 quenched insulin fluorescence, indicating strong interactions between insulin protein molecule and Fe3O4. The fluorescence quenching constants Ksv were obtained as 0.0367 x 10(3), 0.0303 x 10(3) and 0.0131 x 10(3) M and the binding constant K were found to be 27.095, 8.404 and 6.026 mM for Fe3O4, Fe3O4-GSH and Fe3O4-GSH-PAMAM G4, respectively. Both the Ksv and K (binding constant) values revealed that the interaction of Fe3O4 with insulin to be stronger over to dendrimer conjugates. In addition, the FTIR spectra suggested that the presence of nanoparticles results in secondary structure alteration in the insulin conformation. The study implies the critical evaluation of new delivery systems in establishing the biocompatibility, especially when delivered by systemic route. PMID:24804549

Samant, Mayuri; Banerjee, Shashwat S; Taneja, Neetika; Zope, Khushbu; Ghogale, Preetam; Khandare, Jayant J

2014-07-01

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Green fabrication of agar-conjugated Fe3O4 magnetic nanoparticles  

International Nuclear Information System (INIS)

Magnetic nanoparticles are of great interest both for fundamental research and emerging applications. In the biomedical field, magnetite (Fe3O4) has shown promise as a hyperthermia-based tumor therapeutic. However, preparing suitable solubilized magnetite nanoparticles is challenging, primarily due to aggregation and poor biocompatibility. Thus methods for coating Fe3O4 NPs with biocompatible stabilizers are required. We report a new method for preparing Fe3O4 nanoparticles by co-precipitation within the pores of agar gel samples. Permeated agar gels were then dried and ground into a powder, yielding agar-conjugated Fe3O4 nanoparticles. Samples were characterized using XRD, FTIR, TGA, TEM and SQUID. This method for preparing agar-coated Fe3O4 nanoparticles is environmentally friendly, inexpensive and scalable.

2010-11-05

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Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells  

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Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to investigate the cytotoxicity and genotoxicity of MgNPs-Fe3O4 in A549 human lung epithelial cells. MgNPs-Fe3O4 caused cell membrane damage, as assessed by the release of lactate dehydrogenase (LDH)...

Masatoshi Watanabe; Misao Yoneda; Ayaka Morohashi; Yasuki Hori; Daiki Okamoto; Akiko Sato; Daisuke Kurioka; Tadashi Nittami; Yoshifumi Hirokawa; Taizo Shiraishi; Kazuaki Kawai; Hiroshi Kasai; Yukari Totsuka

2013-01-01

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Preparation and characterization of superparamagnetic graphene oxide nanohybrids anchored with Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Highlights: • A new method for fabrication of GPO–Fe3O4 nanostructured hybrid was demonstrated. • The FT-IR analysis of nanohybrid shows infrared peaks characteristic of amide link. • EDX spectrum shows intense peaks for Iron along with carbon and oxygen peaks. • SEM images confirm the presence of Fe3O4 nanoparticles on the GPO surface. • This nanohybrid is a potential material for electromagnetic devices and biomedicine. -- Abstract: We describe a novel method for the preparation of a graphene oxide (GPO) – magnetic nanoparticle (Fe3O4) (GPO–Fe3O4) nanostructured hybrids by a simple and effective method. In this method, the fabrication of multi-component nanostructure system involves covalent attachment of GPO with Fe3O4 through dopamine (do) (GPO–do-Fe3O4). Optical microscopy (OM), ultraviolet spectroscopy (UV), Fourier transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to demonstrate the successful attachment of Fe3O4 to GPO. It was found that the fabricated nanohybrid shows superparamagnetic behavior and allows rapid separation under an external-magnetic field. The FT-IR analysis of GPO–do-Fe3O4 nanohybrid shows infrared (IR) peaks characteristic of amide (-CO-NH-) link on the surface of GPO. TGA analysis clearly shows two major stages of thermal degradation, different from the pattern of observed for dopamine coated Fe3O4 surface. An EDX spectrum of GPO–do-Fe3O4 shows intense peaks for Iron (Fe) along with carbon and oxygen peaks. SEM images further support the FT-IR and TGA results and confirm the presence of Fe3O4 on GPO surface. Thus, the resultant GPO–do-Fe3O4 nanohybrid system carries both electrical and magnetic properties, which are important for applications ranging from electro-magnetic devices to biomedicine

2014-01-15

13

Solid phase extraction of magnetic carbon doped Fe3O4 nanoparticles.  

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Carbon decorated Fe3O4 nanoparticles (Fe3O4/C) are promising magnetic solid-phase extraction (MSPE) sorbents in environmental and biological analysis. Fe3O4/C based MSPE method shows advantages of easy operation, rapidness, high sensitivity, and environmental friendliness. In this paper, the MSPE mechanism of Fe3O4/C nanoparticles has been comprehensively investigated, for the first time, through the following three efforts: (1) the comparison of extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) between the Fe3O4/C sorbents and activated carbon; (2) the chromatographic retention behaviors of hydrophobic and hydrophilic compounds on Fe3O4/C nanoparticles as stationary phase; (3) related MSPE experiments for several typical compounds such as pyrene, naphthalene, benzene, phenol, resorcinol, anisole and thioanisole. It can be concluded that there are hybrid hydrophobic interaction and hydrogen bonding interaction or dipole-dipole attraction between Fe3O4/C sorbents and analytes. It is the existence of carbon and oxygen-containing functional groups coated on the surface of Fe3O4/C nanoparticles that is responsible for the effective extraction process. PMID:24342532

Yang, Jing; Li, Jia-yuan; Qiao, Jun-qin; Lian, Hong-zhen; Chen, Hong-yuan

2014-01-17

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Preparation and antibacterial activity of Fe3O4-Ag nanoparticles  

International Nuclear Information System (INIS)

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

2007-07-18

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Preparation and cell response of bio-mineralized Fe3O4 nanoparticles.  

Science.gov (United States)

Silk fibroin (SF)-coated Fe(3)O(4) nanoparticles (NPs) with good superparamagnetism were successfully prepared via a bio-mineralization process at room temperature. Two cell tests revealed that mineralized SF-coated Fe(3)O(4) NPs presented good cytocompatibility for L929 and osteoblast cells and higher cell density after 5 d with high concentrations of SF-coated Fe(3)O(4) NPs (up to 0.5 mg/mL). These resulted from SF surface coating on NPs, nano-surface morphology and iron ion release of Fe(3)O(4) NPs. The mineralized SF-coated Fe(3)O(4) NPs could be envisioned for various bone orthopedic and therapeutic applications, in which SF-coated NPs location is controlled through an external magnetic field to promoted bone growth. PMID:21821259

Yin, Guangfu; Huang, Zhongbing; Deng, Min; Zeng, Jingwen; Gu, Jianwen

2011-11-01

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Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composite for laccase immobilization  

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Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed randomly onto the surface of Fe3O4 nanoparticles to form molecular dispersion layer and there was a relatively strong bond between central zinc cation and oxygen. The nanoparticle composite took the shape of roundish spheres with the mean diameter of about 15 nm. Active amino groups of magnetic carriers could be used ...

Huang, Jun; Liu, Cheng; Xiao, Haiyan; Wang, Juntao; Jiang, Desheng; Gu, Erdan

2007-01-01

17

Versatile functionalization of Fe3O4 nanoparticles via RAFT polymerization and click chemistry  

International Nuclear Information System (INIS)

Azide-functionalized chain transfer agent (CTA) was synthesized and subsequently employed to mediate the reversible addition fragmentation transfer (RAFT) polymerization of poly(ethylene glycol) monomethacrylate (PEGMA) on the alkyne-functionalized Fe3O4 nanoparticles surface together with click chemistry. In a single pot procedure, azide-functionalized CTA, alkyne-functionalized Fe3O4 and PEGMA were combined to produce the desired product. Fourier transformed infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) results showed that PEGMA chains were grafted to Fe3O4 nanoparticles using RAFT polymerization and click chemistry.

2011-10-01

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1, 3-dipolar cycloaddition as a general route for functionalization of Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Triazole formation by 1, 3-dipolar cycloaddition reactions has been used to functionalize the surface of Fe3O4 nanoparticles. Fe3O4 particle samples with diameters around 22 nm were synthesized without any additional stabilizer, and were then treated with silane coupling agent to react with propargyl acid. The alkynyl group on the Fe3O4 surface provides better conjugation efficiency with azide derivative molecules, which led to their attachment through the formation of a 1, 2, 3-triazole ring

2008-04-30

19

Synthesis of Fe3O4 Nanoparticles from Ironstone Prepared by Polyethylene Glycol 4000  

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Full Text Available This study reports the modification of the preparation method of Fe3O4 nanoparticles, which consists of two stages, beginning with the destruction and separation of iron ore from ironstone. Then, the Fe3O4 nanoparticles are synthesized using the coprecipitation method with magnetite (Fe3O4. Polyethylene glycol (PEG 4000, a readily available chemical, was introduced in varying amounts into the reactions. The ratio of Fe3O4 powder and PEG 4000 is 1:3, 1:4, and 1:5, respectively, and the effects of the PEG 4000 on the morphology, crystalline size, and magnetic properties of the products were studied. It was shown that the particle and crystalline sizes decreased when the concentration of PEG 4000 increased. Additionally, the smallest Fe3O4 nanoparticles were around 50-60 nm, and semispherical nanoparticles were formed. The reduction of the crystalline size with the increase in PEG 4000 was shown by using XRD patterns, with the crystalline size being about 30 nm at a ratio of 1:5 Fe3O4 and PEG 4000, respectively. The hysteresis loop showed low coercivity, indicating that all products were soft magnetic.

Astuti

2014-06-01

20

Pharmacokinetic parameters and tissue distribution of magnetic Fe3O4 nanoparticles in mice  

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Full Text Available Jun Wang1, Yue Chen1, Baoan Chen1, Jiahua Ding1, Guohua Xia1, Chong Gao1, Jian Cheng1, Nan Jin1, Ying Zhou1, Xiaomao Li1, Meng Tang2, Xue Mei Wang21Department of Hematology, Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 1Department of Physics, University of Saarland, D-266041 Saarbruechen, Germany; 2National Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of ChinaBackground: This study explored the pharmacokinetic parameters and tissue distribution of magnetic iron oxide nanoparticles (Fe3O4 MNPs in imprinting control region (ICR mice.Methods: The Fe3O4 MNPs were synthesized by chemical coprecipitation, and their morphology and appearance were observed by transmission electron microscopy. ICR mice were divided into a control group and a Fe3O4 MNP-treated group. Probable target organs in ICR mice were observed, and the pharmacokinetic parameters and biodistribution of Fe3O4 MNPs in tissues were identified using atomic absorption spectrophotometry.Results: Fe3O4 MNPs were spherical with a well distributed particle diameter, and were distributed widely in various target organs and tissues including the heart, liver, spleen, lungs, kidneys, brain, stomach, small intestine, and bone marrow. The majority of Fe3O4 MNPs were distributed to the liver and the spleen. Fe3O4 MNP levels in brain tissue were higher in the Fe3O4 MNP-treated group than in the control group, indicating that Fe3O4 MNPs can penetrate the blood–brain barrier.Conclusion: These results suggest that the distribution of Fe3O4 MNPs was mostly in the liver and spleen, so the curative effect of these compounds could be more pronounced for liver tumors. Furthermore, Fe3O4 MNPs might be used as drug carriers to overcome physiologic barriers.Keywords: magnetic nanoparticles, Fe3O4, tissue distribution, mice

Jun Wang

2010-10-01

 
 
 
 
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Magnetic properties of Fe3O4 nanoparticles coated with oleic and dodecanoic acids  

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Magnetic nanoparticles (NP) of magnetite (Fe3O4) coated with oleic acid (OA) and dodecanoic acid (DA) were synthesized and investigated through Transmission Electron Microscopy (TEM),magnetization M, and ac magnetic susceptibility measurements. The OA coated samples were produced with different magnetic concentrations (78, 76, and 65%) and the DA sample with 63% of Fe3O4. Images from TEM indicate that the NP have a nearly spherical geometry and mean diameter ~ 5.5 nm. Magnet...

Barbeta, V. B.; Jardim, R. F.; Kiyohara, P. K.; Effenberger, F. B.; Rossi, L. M.

2010-01-01

22

Ultrasonic-assisted in situ synthesis and characterization of superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Highlights: ? Fe3+ as the only Fe source for preparing Fe3O4 nanoparticles through in situ cover and sonication method. ? Surface modification enables the reduction of the grain size of Fe3O4. ? Increasing temperature reduces grain size of Fe3O4 until it exceeds 80 deg. C. ? Increasing pH values reduces grain size of Fe3O4 until it exceeds 11. ? Saturation magnetizations depend on the grain size of Fe3O4 nanoparticles. - Abstract: Superparamagnetic Fe3O4 nanoparticles were synthesized via a modified coprecipitation method, and were characterized with X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Zeta potential and FT-IR, respectively. The influences of different kinds of surfactants (sodium dodecyl benzene sulfonate, polyethyleneglycol, oleic acid and dextran), temperatures and pH values on the grain size and properties were also investigated. In this method, Fe3+ was used as the only Fe source and partially reduced to Fe2+ by the reducing agent with precise content. The following reaction between Fe3+, Fe2+ and hydroxide radical brought pure Fe3O4 nanoparticles. The tiny fresh nanoparticles were coated in situ with surfactant under the action of sonication. Comparing with uncoated sample, the mean grain size and saturation magnetization of coated Fe3O4 nanoparticles decrease from 18.4 nm to 5.9-9.0 nm, and from 63.89 emu g-1 to 52-58 emu g-1 respectively. When oleic was used as the surfactant, the mean grain size of Fe3O4 nanoparticles firstly decreases with the increase of reaction temperature, but when the temperature is exceed to 80 deg. C, the continuous increase of temperature resulted in larger nanoparticles. the grain size decreases gradually with the increasing of pH values, and it remains unchanged when the PH value is up to 11. The saturation magnetization of as-prepared Fe3O4 nanoparticles always decreases with the fall of grain size.

2011-09-15

23

The reversal effect of magnetic Fe3O4 nanoparticles loaded with cisplatin on SKOV3/DDP ovarian carcinoma cells  

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To explore whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) loaded with cisplatin can reverse the diaminedichloro platinum (DDP) resistance to multidrug resistance of ovarian carcinoma cells and to investigate its mechanisms. The SKOV3/DDP cells were divided into DDP treatment (DDP group), MNPs-Fe3O4 treatment (MNPs-Fe3O4 group), DDP + MNPs-Fe3O4 treatment (DDP + MNPs-Fe3O4 group), and control group. After incubation with those conjugates for 48 h, the cytotoxic effects were measured ...

Jiang, Zhi; Chen, Bao-an; Xia, Guo-hua; Wu, Qiang; Zhang, Yu; Hong, Tie-yan; Zhang, Wei; Cheng, Jian; Gao, Feng; Liu, Li-jie; Li, Xiao-mao; Wang, Xue-mei

2009-01-01

24

Multifunctional magnetic Fe3O4 nanoparticles combined with chemotherapy and hyperthermia to overcome multidrug resistance  

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Full Text Available Yanyan Ren1,2,*, Haijun Zhang1,2,*, Baoan Chen1, Jian Cheng1, Xiaohui Cai1, Ran Liu1, Guohua Xia1, Weiwei Wu1, Shuai Wang1, Jiahua Ding1, Chong Gao1, Jun Wang1, Wen Bao1, Lei Wang1, Liang Tian1, Huihui Song1, Xuemei Wang1,2 1Department of Hematology and Oncology, Key Medical Discipline, Jiangsu Province, Zhongda Hospital, and Faculty of Oncology, Medical School, Nanjing, 2State Key Laboratory of Bioelectronics, Southeast University, Nanjing, People's Republic of China*These authors contributed equally to this workBackground: Multidrug resistance in cancer is a major obstacle for clinical therapeutics, and is the reason for 90% of treatment failures. This study investigated the efficiency of novel multifunctional Fe3O4 magnetic nanoparticles (Fe3O4-MNP combined with chemotherapy and hyperthermia for overcoming multidrug resistance in an in vivo model of leukemia.Methods: Nude mice with tumor xenografts were randomly divided into a control group, and the treatment groups were allocated to receive daunorubicin, 5-bromotetrandrine (5-BrTet and daunorubicin, Fe3O4-MNP, and Fe3O4-MNP coloaded with daunorubicin and 5-bromotetrandrine (Fe3O4-MNP-DNR-5-BrTet, with hyperthermia in an alternating magnetic field. We investigated tumor volume and pathology, as well as P-glycoprotein, Bcl-2, Bax, and caspase-3 protein expression to elucidate the effect of multimodal treatment on overcoming multidrug resistance.Results: Fe3O4-MNP played a role in increasing tumor temperature during hyperthermia. Tumors became significantly smaller, and apoptosis of cells was observed in both the Fe3O4-MNP and Fe3O4-MNP-DNR-5-BrTet groups, especially in the Fe3O4-MNP-DNR-5-BrTet group, while tumor volumes in the other groups had increased after treatment for 12 days. Furthermore, Fe3O4-MNP-DNR-5-BrTet with hyperthermia noticeably decreased P-glycoprotein and Bcl-2 expression, and markedly increased Bax and caspase-3 expression.Conclusion: Fe3O4-MNP-DNR-5-BrTet with hyperthermia may be a potential approach for reversal of multidrug resistance in the treatment of leukemia.Keywords: magnetic nanoparticles, daunorubicin, 5-bromotetrandrine, multidrug resistance, hyperthermia

Ren Y

2012-05-01

25

Biomimetic mussel adhesive inspired clickable anchors applied to the functionalization of fe(3) o(4) nanoparticles.  

Science.gov (United States)

The functionalization of magnetite (Fe(3) O(4) ) nanoparticles with dopamine-derived clickable biomimetic anchors is reported. Herein, an alkyne-modified catechol-derivative is employed as the anchor, as i) the catechol-functional anchor groups possess irreversible covalent binding affinity to Fe(3) O(4) nanoparticles, and ii) the alkyne terminus enables further functionalization of the nanoparticles by the grafting-onto approach with various possibilities offered by 'click' chemistry. In the present work, azido-end group functionalized Rhodamine and poly(ethylene glycol) (PEG) are utilized to coat the iron oxide nanoparticles to make them fluorescent and water soluble. PMID:21567571

Goldmann, Anja S; Schödel, Christine; Walther, Andreas; Yuan, Jiayin; Loos, Katja; Müller, Axel H E

2010-09-15

26

Fates of Fe3O4 and Fe3O4@SiO2 nanoparticles in human mesenchymal stem cells assessed by synchrotron radiation-based techniques.  

Science.gov (United States)

Superparamagnetic iron oxide nanoparticles (SPIOs) have been widely used as the magnetic resonance imaging (MRI) contrast agent in biomedical studies and clinical applications, with special interest recently in in vivo stem cell tracking. However, a full understanding of the fate of SPIOs in cells has not been achieved yet, which is particularly important for stem cells since any change of the microenvironment may disturb their propagation and differentiation behaviors. Herein, synchrotron radiation-based X-ray fluorescence (XRF) in combination with X-ray absorption spectroscopy (XAS) were used to in situ reveal the fate of Fe3O4 and Fe3O4@SiO2 NPs in human mesenchymal stem cells (hMSCs), in which the dynamic changes of their distribution and chemical speciation were precisely determined. The XAS analysis evidences that Fe3O4 NPs cultured with hMSCs are quite stable and almost keep their initial chemical form up to 14 days, which is contradictory to the previous report that Fe3O4 NPs were unstable in cell labeling assessed by using a simplified lysosomal model system. Coating with a SiO2 shell, Fe3O4@SiO2 NPs present higher stability in hMSCs without detectable changes of their chemical form. In addition, XRF analysis demonstrates that Fe3O4@SiO2 NPs can label hMSCs in a high efficiency manner and are solely distributed in cytoplasm during cell proliferation, making it an ideal probe for in vivo stem cell tracking. These findings with the help of synchrotron radiation-based XAS and XRF improve our understanding of the fate of SPIOs administered to hMSCs and will help the future design of SPIOs for safe and efficient stem cells tracking. PMID:24814428

Tian, Fei; Chen, Guangcun; Yi, Peiwei; Zhang, Jichao; Li, Aiguo; Zhang, Jing; Zheng, Lirong; Deng, Zongwu; Shi, Qin; Peng, Rui; Wang, Qiangbin

2014-08-01

27

Monodispersed core-shell Fe3O4(at)Au nanoparticles  

International Nuclear Information System (INIS)

The ability to synthesize and assemble monodispersed core-shell nanoparticles is important for exploring the unique properties of nanoscale core, shell, or their combinations in technological applications. This paper describes findings of an investigation of the synthesis and assembly of core (Fe3O4)-shell (An) nanoparticles with high monodispersity. Fe3O4 nanoparticles of selected sizes were used as seeding materials for the reduction of gold precursors to produce gold-coated Fe3O4 nanoparticles (Fe3O4(at)Au). Experimental data from both physical and chemical determinations of the changes in particle size, surface plasmon resonance optical band, core-shell composition, surface reactivity, and magnetic properties have confirmed the formation of the core-shell nanostructure. The interfacial reactivity of a combination of ligand-exchanging and interparticle cross-linking was exploited for molecularly mediated thin film assembly of the core-shell nanoparticles. The SQUID data reveal a decrease in magnetization and blocking temperature and an increase in coercivity for Fe3O4(at)Au, reflecting the decreased coupling of the magnetic moments as a result of the increased interparticle spacing by both gold and capping shells. Implications of the findings to the design of interfacial reactivities via core-shell nanocomposites for magnetic, catalytic, and biological applications are also briefly discussed

2005-12-15

28

Catalytic wet air oxidation of phenol over Co-doped Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

The Fe3O4 nanoparticles doped with cobalt ions have been successfully synthesized by the co-precipitation process. The X-ray diffraction, inductively coupled plasma, scanning electron microscopy, and transmission electron microscopy were used to characterize the as-prepared nanoparticles. The results show that the phase structure of the nanoparticles is spinel structure of pure Fe3O4 with the particle size ranging from 40 to 50 nm. The Co-doping concentration can be controlled by changing the atomic ratio of the stock materials. The catalytic activity of the Co-doped Fe3O4 was further investigated by decomposing the phenol in liquid phase. The results show that cobalt ions doping can improve the catalytic efficiency of Fe3O4 nanoparticles in phenol degradation with catalytic reaction fitting the first-order kinetics. According to the estimated reaction rate of Co-doped Fe3O4 nanoparticles at different temperatures, the activation energy was calculated to be 45.63 kJ/mol

2013-08-01

29

The Nature of Magnetic State of Small Fe3O4 Nanoparticles  

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Full Text Available We have investigated the nature of the magnetic state of 4 nm and 7 nm magnetite Fe3O4 nanoparticles and show that they form a collective superspin glass state. Magnetic force on the nanoparticles relevant to the tumor targeting application was determined as well.

J. Dolinšek

2011-12-01

30

Preparation of magnetic Fe3O4@SiO2 nanoparticles for immobilization of lipase.  

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Magnetic Fe3O4 nanoparticles were prepared with coprecipitatation method and covered with SiO2 to form the core-shell Fe3O4@SiO2 nanoparticles. Then the nanoparticles were modified with glutaradehyde for functionalization of the surface to aldehyde groups. The transmission electron microscopy confirmed the core-shell structure and revealed that the size of the nanoparticles was around 10 nm. It was observed that the lipase was immobilized on the nanoparticles successfully from the Fourier transform infrared spectra. The immobilized lipase on Fe3O4@SiO2 nanoparticles was characterized and compared to free enzyme. There are no significant differences observed in the optimal pH, temperature and Km before and after immobilization. However, the immobilized lipase displayed higher relative activity in the range of pH from 7.0 to 9.5. Compare with the free enzyme, the immobilized one showed higher thermal stability at temperature range from 30 to 70 degrees C, especially at high temperature. The relative activity of immobilized enzyme was 5.8 fold of the free lipase at 70 degrees C after 10 h incubation. Thus, the prepared lipase was proved to have the advantages like higher relative activity, better stability, broader pH range and easy to recovery. These results suggest that immobilization of lipase on Fe3O4@SiO2 nanoparticles has the potential industrial applications. PMID:24734736

Liu, Wei; Zhou, Fang; Zhang, Xiao-Yun; Li, Yue; Wang, Xiang-Yu; Xu, Xi-Ming; Zhang, Ye-Wang

2014-04-01

31

Green synthesis and characterization of superparamagnetic Fe 3O 4 nanoparticles  

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In this paper, we have first demonstrated a facile and green synthetic approach for preparing superparamagnetic Fe 3O 4 nanoparticles using ?- D-glucose as the reducing agent and gluconic acid (the oxidative product of glucose) as stabilizer and dispersant. The X-ray powder diffraction (XRD), X-ray photoelectron spectrometry (XPS), and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe 3O 4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that Fe 3O 4 nanoparticles were roughly spherical shape and its average size was about 12.5 nm. The high-resolution TEM (HRTEM) result proved that the nanoparticles were structurally uniform with a lattice fringe spacing about 0.25 nm, which corresponded well with the values of 0.253 nm of the (3 1 1) lattice plane of the inverse spinel Fe 3O 4 obtained from the JCPDS database. The superconducting quantum interference device (SQUID) results revealed that the blocking temperature ( Tb) was 190 K, and that the magnetic hysteresis loop at 300 K showed a saturation magnetization of 60.5 emu/g, and the absence of coercivity and remanence indicated that the as-synthesized Fe 3O 4 nanoparticles had superparamagnetic properties. Fourier transform infrared spectroscopy (FT-IR) spectrum displayed that the characteristic band of Fe-O at 569 cm -1 was indicative of Fe 3O 4. This method might provide a new, mild, green, and economical concept for the synthesis of other nanomaterials.

Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

2010-07-01

32

Encapsulated Fe3O4 nanoparticles with silica thin layer as an anode material for lithium secondary batteries  

International Nuclear Information System (INIS)

Fe3O4 nanoparticles were coated with a SiO2 layer by using a modified sol-gel method. The synthetic procedures for Fe3O4 nanoparticles encapsulated with a SiO2 layer (SiO2-Fe3O4) consist of three consecutive steps: (i) fabrication of Fe3O4 by the co-precipitation method, (ii) stabilization of Fe3O4 with citrate as a capping agent, which is used to prevent particles from aggregating, and (iii) silica encapsulation by a modified sol-gel reaction. Based on the experimental range, SiO2-Fe3O4 exhibited higher cyclic performance than the intrinsic one. The reversible capacity of Fe3O4 with SiO2 at the first cycle was 363 mA h g-1 and the remaining discharge capacity was 321 mA h g-1 after the 30th cycle.

2010-05-01

33

Synthesis of Fe3O4 nanoparticles with tunable and uniform size through simple thermal decomposition.  

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A novel and facile method with low cost has been developed to fabricate Fe3O4 nanoparticles (NPs) with tunable and uniform sizes by the thermal decomposition of iron oleate complex. The synthesis of iron oleate complex was carried out using a reaction between oleic acid and FeCl3 x 6H2O at low temperature. The decomposition of iron oleate complex occurs when the complex added in the solution of octadecene (ODE) and trioctylamine (TOA) with simple heat treatment. The X-ray diffraction pattern of a resulting sample indicated that Fe3O4 NPs formed during the decomposition of iron oleate complex. Preparation conditions including reaction time and temperature, the concentration of the complex, and the ratio of TOA and ODE strikingly affected the size and size distribution of resulting Fe3O4 NPs. Under optimal preparation conditions, the size of Fe3O4 NPs was adjusted (less than 20 nm in average diameter). The analysis of samples by a Fourier transform infrared spectroscopy confirmed the formation of iron oleate complex. Because the Fe3O4 NPs revealed a superparamagnetic property as well as tunable and uniform sizes, the NPs will be utilizable for further applications. This simple strategy with low cost has to give a useful enlightenment for the design and fabrication of magnetic oxide. PMID:22962760

Wang, Dan; Ma, Qian; Yang, Ping

2012-08-01

34

Green synthesis of soya bean sprouts-mediated superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Superparamagnetic Fe3O4 nanoparticles were first synthesized via soya bean sprouts (SBS) templates under ambient temperature and normal atmosphere. The reaction process was simple, eco-friendly, and convenient to handle. The morphology and crystalline phase of the nanoparticles were determined from scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) spectra. The effect of SBS template on the formation of Fe3O4 nanoparticles was investigated using X-ray photoemission spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR). The results indicate that spherical Fe3O4 nanoparticles with an average diameter of 8 nm simultaneously formed on the epidermal surface and the interior stem wall of SBS. The SBS are responsible for size and morphology control during the whole formation of Fe3O4 nanoparticles. In addition, the superconducting quantum interference device (SQUID) results indicate the products are superparamagnetic at room temperature, with blocking temperature (TB) of 150 K and saturation magnetization of 37.1 emu/g.

2010-10-01

35

Synthesis of size-controlled Fe3O4@SiO2 magnetic nanoparticles for nucleic acid analysis.  

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We present a systematic study on the preparation, characteration and potential application of Fe3O4 and Fe3O4@SiO2 nanoparticles. Fe3O4 nanoparticles of controllable diameters were successfully synthesized by solvothermal system with tuning pH. The magnetic properties of nanoparticles were measured by vibration sample magnetometer. Fe3O4@ SiO2 nanoparticles were obtained via classic Stöber process. Streptavidin coated Fe3O4@SiO2 nanoparticles were prepared by covalent interaction. The quantity of streptavidin bound to nanoparticles was determined by UV-Vis spectrometer. To evaluate the binding efficiency and capacity of nucleic acid on nanoparticles, the capture of biotinylated oligonucleotide on streptavidin coated Fe3O4@SiO2 nanoparticles at different concentration was estimated by fluorescence detection. Both Fe3O4 and Fe3O4@SiO2 nanoparticles exhibited well crystallization and magnetic properties. The maximal amount of streptavidin immobilized onto the Fe3O4@SiO2 nanoparticles was 29.3 microg/mg. The saturation ratio of biotinylated oligonucleotides captured on streptavidin coated Fe3O4@SiO2 nanoparticles was 5 microM/mg within 20 minutes, indicating that FeO4@SiO2 nanoparticles immobilized by streptavidin were excellent carriers in nucleic acid analysis due to their convenient magnetic-separation property. Therefore, the synthesized Fe3O4 and Fe3O4@SiO2 nanoparticles with controllable size and high magnetic saturation have shown great application potentials in nucleic acid research. PMID:22523975

Sun, Huanxiang; Zeng, Xin; Liu, Ming; Elingarami, Sauli; Li, Guopeng; Shen, Bin; He, Nongyue

2012-01-01

36

Preparation of surface plasmon resonance biosensor based on magnetic core/shell Fe3O4/SiO2 and Fe3O4/Ag/SiO2 nanoparticles.  

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In this paper, surface plasmon resonance biosensors based on magnetic core/shell Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were developed for immunoassay. With Fe(3)O(4) and Fe(3)O(4)/Ag nanoparticles being used as seeding materials, Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles were formed by hydrolysis of tetraethyl orthosilicate. The aldehyde group functionalized magnetic nanoparticles provide organic functionality for bioconjugation. The products were characterized by scanning electronic microscopy (SEM), transmission electronic microscopy (TEM), FTIR and UV-vis absorption spectrometry. The magnetic nanoparticles possess the unique superparamagnetism property, exceptional optical properties and good compatibilities, and could be used as immobilization matrix for goat anti-rabbit IgG. The magnetic nanoparticles can be easily immobilized on the surface of SPR biosensor chip by a magnetic pillar. The effects of Fe(3)O(4)/SiO(2) and Fe(3)O(4)/Ag/SiO(2) nanoparticles on the sensitivity of SPR biosensors were also investigated. As a result, the SPR biosensors based on Fe(3)O(4)/SiO(2) nanoparticles and Fe(3)O(4)/Ag/SiO(2) nanoparticles exhibit a response for rabbit IgG in the concentration range of 1.25-20.00 ?g ml(-1) and 0.30-20.00 ?g ml(-1), respectively. PMID:21353500

Wang, Liying; Sun, Ying; Wang, Jing; Wang, Jian; Yu, Aimin; Zhang, Hanqi; Song, Daqian

2011-06-01

37

Biocompatibility of magnetic Fe3O4 nanoparticles and their cytotoxic effect on MCF-7 cells  

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Full Text Available Daozhen Chen,1,3,* Qiusha Tang,2,* Xiangdong Li,3,* Xiaojin Zhou,1 Jia Zang,1 Wen-qun Xue,1 Jing-ying Xiang,1 Cai-qin Guo11Central Laboratory, Wuxi Hospital for Matemaland Child Health Care Affiliated Medical School of Nanjing, Jiangsu Province; 2Department of Pathology and Pathophysiology, Medical College, Southeast University, Jiangsu Province; 3The People’s Hospital of Aheqi County, Xinjiang, China *These authors contributed equally to this workBackground: The objective of this study was to evaluate the synthesis and biocompatibility of Fe3O4 nanoparticles and investigate their therapeutic effects when combined with magnetic fluid hyperthermia on cultured MCF-7 cancer cells.Methods: Magnetic Fe3O4 nanoparticles were prepared using a coprecipitation method. The appearance, structure, phase composition, functional groups, surface charge, magnetic susceptibility, and release in vitro were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. Blood toxicity, in vitro toxicity, and genotoxicity were investigated. Therapeutic effects were evaluated by MTT [3-(4, 5-dimethyl-2-thiazolyl-2, 5-diphenyl-2H-tetrazolium bromide] and flow cytometry assays.Results: Transmission electron microscopy revealed that the shapes of the Fe3O4 nanoparticles were approximately spherical, with diameters of about 26.1 ± 5.2 nm. Only the spinel phase was indicated in a comparison of the x-ray diffraction data with Joint Corporation of Powder Diffraction Standards (JCPDS X-ray powder diffraction files. The O-to-Fe ratio of the Fe3O4 was determined by scanning electron microscopy-energy dispersive x-ray spectroscopy elemental analysis, and approximated pure Fe3O4. The vibrating sample magnetometer hysteresis loop suggested that the Fe3O4 nanoparticles were superparamagnetic at room temperature. MTT experiments showed that the toxicity of the material in mouse fibroblast (L-929 cell lines was between Grade 0 to Grade 1, and that the material lacked hemolysis activity. The acute toxicity (LD50 was 8.39 g/kg. Micronucleus testing showed no genotoxic effects. Pathomorphology and blood biochemistry testing demonstrated that the Fe3O4 nanoparticles had no effect on the main organs and blood biochemistry in a rabbit model. MTT and flow cytometry assays revealed that Fe3O4 nano magnetofluid thermotherapy inhibited MCF-7 cell proliferation, and its inhibitory effect was dose-dependent according to the Fe3O4 nano magnetofluid concentration.Conclusion: The Fe3O4 nanoparticles prepared in this study have good biocompatibility and are suitable for further application in tumor hyperthermia.Keywords: characterization, biocompatibility, Fe3O4, magnetic nanoparticles, hyperthermia

Chen DZ

2012-09-01

38

Use of Fe3O4 Nanoparticles for Enhancement of Biosensor Response to the Herbicide 2,4-Dichlorophenoxyacetic Acid  

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Magnetic nanoparticles of Fe3O4 were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe3O4 nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP) and Fe3O4 nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P). The incorporation of the Fe3O4 nanoparticles togethe...

Kee-Shyuan Loh; Yook Heng Lee; Ahmad Musa; Abdul Aziz Salmah; Ishak Zamri

2008-01-01

39

A comprehensive study on the synthesis and paramagnetic properties of PEG-coated Fe3O4 nanoparticles  

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The PEG-coated Fe3O4 (PEG-Fe3O4) nanoparticles had been fabricated through chemical coprecipitation method. We comprehensively investigated the influence of different reaction conditions, such as vapor pressures with opening or sealing the beaker, molecular weights and amounts of PEG, on the structural and paramagnetic properties of PEG-Fe3O4 nanoparticles. The well-dispersed magnetic PEG-Fe3O4 nanoparticles with better size distribution can be obtained with adding 4 g PEG1000 while sealing the beaker. The possible growth mechanism was also discussed in detail.

Yang, Jinghai; Zou, Ping; Yang, Lili; Cao, Jian; Sun, Yunfei; Han, Donglai; Yang, Shuo; Wang, Zhe; Chen, Gang; Wang, Bingji; Kong, Xiangwang

2014-06-01

40

Magnetic study of Fe3O4 nanoparticles incorporated within mesoporous silicon  

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Porous silicon PS matrices with oriented, separated pores grown perpendicular to the surface are used as a template for the incorporation of magnetite nanoparticles. The Fe3O4 particles used for infiltration into the PS template are coated with oleic acid in a hexane solution and exhibit an average diameter of 8 1.5 nm. The narrow size distribution and the superparamagnetic behavior at room temperature are interesting features of these nanoparticles. In addition, the use of PS as...

Venkatesan, Munuswamy

2010-01-01

 
 
 
 
41

Simple solvothermal synthesis of hydrophobic magnetic monodispersed Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Graphical abstract: A facile method to produce monodispersed magnetite nanoparticles is based on the solvothermal reaction of iron acetylacetonate (Fe(acac)3) decomposition. The sizes ranged from 7 to 12 nm, which could be controlled by adjusting the volume ratio of oleylamine to n-hexane. Display Omitted Highlights: ? The solvethermal reaction of Fe(acac)3 decomposition was carried out at mild temperature in the presence of oleylamine and n-hexane. ? The size of nanocrystals is controlled by adjusting the volume ratio of oleylamine to n-hexane. ? The low-boiling-point solvent n-hexane offered autogenous pressure parameter after gasified in the reaction temperature. ? The as prepared hydrophobic monodisperse Fe3O4 NPs can be used to prepare the magnetic micelles for future biomedical applications. -- Abstract: A new solvothermal method is proposed for the preparation of Fe3O4 nanoparticles (NPs) from iron acetylacetonate in the presence of oleylamine and n-hexane. The products are characterized by X-ray powder diffraction, infrared (IR) spectroscopy, transmission electron microscopy, thermogravimetry/differential thermogravimetry (TG/DTG) analysis, and vibrating sample magnetometery. The new procedure yields superparamagnetic monodispersed Fe3O4 particles with sizes ranging from 7 nm to 12 nm. The nanocrystal sizes are controlled by adjusting the volume ratio of oleylamine to n-hexane. IR and TG/DTG analyses indicate that the oleylamine molecules, as stabilizers, are adsorbed on the surface of Fe3O4 NPs as bilayer adsorption models. The surface adsorption quantities of oleylamine on 7.5 and 10.4 nm-diameter Fe3O4 NPs are 18% and 11%, respectively. The hydrophobic surface of the obtained nanocrystals is passivated by adsorbed organic solvent molecules. These molecules provide stability against agglomeration, enable solubility in nonpolar solvents, and allow the formation of magnetic polymer micelles.

2013-02-01

42

Fe3O4 nanoparticles embedded in carbon-framework as anode material for high performance lithium-ion batteries  

International Nuclear Information System (INIS)

Highlights: ? Fe3O4 nanoparticles are embedded in the three-dimensional carbon-framework. ? Carbon layers and Fe3O4 nanoparticles bulid a special micro-nanostructure. ? Carbon-framework favors fast electrons transportation during the charge/discharge process. ? Carbon-framework improves the cyclic stability of the composite. ? Fe3O4/C composite show higher capacity retention in comparison with that of Fe3O4 nanoparticles. - Abstract: Fe3O4/C composites have been prepared by sucrose calcining with Fe3O4 particles obtained from ferrous oxalate decomposition. The scanning electron microscopy (SEM) images show that Fe3O4 nanoparticles (Fe3O4 NPS) with average size of 200 nm are embedded in the three-dimensional (3D) carbon-framework. As an anode material for rechargeable lithium-ion batteries, the Fe3O4/C composite delivers a reversible capacity of 773 mAh g?1 at a current density of 924 mA g?1 after 200 cycles, higher than that of the bare Fe3O4 NPS which only retain a capacity of 350 mAh g?1. When the current density rises to 1848 mA g?1, Fe3O4/C material still remains 670 mAh g?1 even after 400 cycles. The enhanced high-rate performance can be attributed to the 3D carbon-framework, which improves the electric conductivity, relaxes the strain stress and prevents the aggregation of Fe3O4 particles during the charge/discharge process.

2012-11-30

43

Alcohol dependent production of Fe3O4 and CoFe2O4 nanoparticles.  

Science.gov (United States)

Commonly available alcohols of varying lengths and degree of branching were used to synthesize iron oxide, Fe3O4, and cobalt iron oxide, CoFe2O4, nanoparticles by means of a simple solvothermal decomposition of iron (III) acetylacetonates and cobalt (II) acetylacetonates. Depending on the solvent employed resulting Fe3O4 and CoFe2O4 nanoparticles ranged in size from approximately 5-16 nm and approximately 4-8 nm, respectively. All alcohols utilized resulted in the formation of nanoparticles with a spinel crystal structure, with the exception of methanol. Use of tert-butanol and phenol resulted in nearly spherical agglomerations of individual nanoparticles ranging between 100-250 nm. The resulting structures and morphologies of all samples were confirmed by X-ray diffraction and electron microscopy. Mass specific moments are reported based on SQUID magnetometry, and ranged from 57.5(5)-76.4(3) emu/g for Fe3O4 and 47.7(7)-67.0(4) emu/g CoFe2O4. PMID:23862521

Yocum, Brandon J; Ekiert, Thomas F; Alexander, Max D; O'Malley, Matthew J

2013-06-01

44

Controlled synthesis and self-assembly of dendrite patterns of Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

A method for the growth and self-assembly of Fe3O4 nanoparticles that is template assisted, as well as gas diffusion and surface tension controlled, has been developed at room temperature. Well-defined dendrite patterns of Fe3O4 nanoparticles were obtained upon ion (Fe3+/Fe2+) entrapment in a polyethylene glycol solution followed by NH3 gas exposure on the surface of an aqueous solution on the glass substrate. During the formation of Fe3O4 nanoparticles, the diffusion of volatile NH3 limits the hydrolysis rate of the molecular precursor and catalyzes slow formation. The template and surface tension also provided significant driving forces to promote the formation of dendrite patterns and influence the nature of the pattern. The Fe3+/Fe2+ concentration was varied in order to see the affects on the template molecular weight. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and SQUID measurements were used to characterize the final product. The derived patterned structure can be tailored by a simple combination of the physical and chemical procedure, which provides a new opportunity for obtaining a controllable pattern of nanoparticles.

2009-01-21

45

Identification of ferrous-ferric Fe3O4 nanoparticles in recombinant human ferritin cages.  

Science.gov (United States)

Recombinant ferritin is an excellent template for the synthesis of magnetic nanoparticles. This paper describes carefully performed experiments both to identify ironoxides within nanoparticles and to measure the number of iron atoms in the cores of recombinant human H-chain ferritin (HFn), based on spectroscopy techniques. Using electron energy-loss spectroscopy (EELS) analysis, magnetite (Fe3O4) has been unequivocally identified as the ironoxide formed within HFn cores under special preparation conditions. Atom counting analysis by EELS and high-angle annular dark-field imaging further allowed the correlation of the particle sizes to the real Fe atom numbers in a quantitative manner. These results help clarify some structural confusion between magnetite and maghemite (?-Fe2O3), and also provide standard data for the number of Fe atoms within Fe3O4 particles of a given size, whose use is not limited to cases of magnetite synthesized in the cores of recombinant human ferritin. PMID:23800760

Walls, Michael G; Cao, Changqian; Yu-Zhang, Kui; Li, Jinhua; Che, Renchao; Pan, Yongxin

2013-08-01

46

The effect of magnetic nanoparticles of Fe3O4 on immune function in normal ICR mice  

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We investigated the effect of magnetic nanoparticles of Fe3O4 (Fe3O4-MNPs) on the mice immune system. Imprinting control region (ICR) mice were assigned randomly into four groups and treated with normal saline or low, medium, or high doses of Fe3O4-MNPs, respectively. After intravenous administration of Fe3O4-MNPs for 72 hours, the peripheral T cells and the induction of primary immune responses in mice were investigated by flow cytometry and determined using enzyme-linked immunosorbent assay...

Chen, Bao-an; Jin, Nan; Wang, Jun; Ding, Jiahua; Gao, Chong; Cheng, Jian; Xia, Guohua; Gao, Feng; Zhou, Yin; Chen, Yue; Zhou, Guina; Li, Xiaomao; Zhang, Yu; Tang, Men; Wang, Xuemei

2010-01-01

47

Preparation and characterization of spindle-like Fe3O4 mesoporous nanoparticles  

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Magnetic spindle-like Fe3O4 mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like ?-Fe2O3 NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desor...

Zhang, Shaofeng; Wu, Wei; Xiao, Xiangheng; Zhou, Juan; Ren, Feng; Jiang, Changzhong

2011-01-01

48

Microwave synthesis of magnetic Fe3O4 nanoparticles used as a precursor of nanocomposites and ferrofluids  

International Nuclear Information System (INIS)

Methods to synthesize magnetic Fe3O4 nanoparticles and to modify the surface of particles are presented in the present investigation. Fe3O4 magnetic nanoparticles were prepared by the co-precipitation of Fe3+ and Fe2+, NH3.H2O was used as the precipitating agent to adjust the pH value, and the aging of Fe3O4 magnetic nanoparticles was accelerated by microwave (MW) irradiation. The obtained Fe3O4 magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and vibrating sample magnetometer (VSM). The average size of Fe3O4 crystallites was found to be around 8-9 nm. Thereafter, the surface of Fe3O4 magnetic nanoparticles was modified by stearic acid. The resultant sample was characterized by FT-IR, scanning electron microscopy (SEM), XRD, lipophilic degree (LD) and sedimentation test. The FT-IR results indicated that a covalent bond was formed by chemical reaction between the hydroxyl groups on the surface of Fe3O4 nanoparticles and carboxyl groups of stearic acid, which changed the polarity of Fe3O4 nanoparticles. The dispersion of Fe3O4 in organic solvent was greatly improved. Effects of reaction time, reaction temperature and concentration of stearic acid on particle surface modification were investigated. In addition, Fe3O4/polystyrene (PS) nanocomposite was synthesized by adding surface modified Fe3O4 magnetic nanoparticles into styrene monomer, followed by the radical polymerization. The obtained nanocomposite was tested by thermogravimetry (TG), differential scanning calorimetry (DSC) and XRD. Results revealed that the thermal stability of PS was not significantly changed after adding Fe3O4 nanoparticles. The Fe3O4 magnetic fluid was characterized using UV-vis spectrophotometer, Gouy magnetic balance and laser particle-size analyzer. The testing results showed that the magnetic fluid had excellent stability, and had susceptibility of 4.46x10-8 and saturated magnetization of 6.56 emu/g. In addition, the mean size d (0.99) of magnetic Fe3O4 nanoparticles in the fluid was 36.19 nm

2006-08-01

49

Effect of a SiO2 coating on the magnetic properties of Fe3O4 nanoparticles  

Science.gov (United States)

In this work the effect of a SiO2 coating on the magnetic properties of Fe3O4 nanoparticles obtained by the sol-gel method is analyzed. Two sets of samples were prepared: Fe3O4 nanoparticles and Fe3O4@SiO2 core-shell composites. The samples display the characteristic spinel structure associated with the magnetite Fe3O4 phase, with the majority of grain sizes around 5-10 nm. At room temperature the nanoparticles show the characteristic superparamagnetic behavior with mean blocking temperatures around 160 and 120 K for Fe3O4 and Fe3O4@SiO2, respectively. The main effect of the SiO2 coating is reflected in the temperature dependence of the high field magnetization (?0H = 6 T), i.e. deviations from the Bloch law at low temperatures (T Fe3O4 nanoparticles. A significant decrease (around 26%) is found in the SAR values of the SiO2 coated nanocomposite. The different heating response is analyzed in terms of the decrease of the effective nanoparticle magnetization in the Fe3O4@SiO2 core-shell composites at room temperature.

Larumbe, S.; Gómez-Polo, C.; Pérez-Landazábal, J. I.; Pastor, J. M.

2012-07-01

50

Study on the Synthesis and Properties of Superparamagnetic Monodisperse Fe3O4 Nanoparticles  

Directory of Open Access Journals (Sweden)

Full Text Available There are extensive applications for superparamagnetic Fe3O4 nanoparticles in the field of biomaterials. Superparamagnetic magnetite nanoparticles coated with oleic acid were prepared in the refluxing mixed system of water, ethanol alcohol and toluene at 74¡?The effect of the OH- concentration on the surface properties, size, dispersion and magnetic properties of magnetite nanoparticles was studied systematically. The properties of magnetite nanoparticles were tested by X-ray diffraction (XRD, fourier transform infrared (FTIR, dynamic light scattering (DLS, transmission electron microscopy (TEM and vibrating sample magnetometer (VSM. The results show that when the molar ratio of NaOH to Fe(¢

JIANG Wen,WEN Xian-Tao,WANG Wei,WU Yao,GU Zhong-Wei

2009-07-01

51

Folate-conjugated luminescent Fe3O4 nanoparticles for magnetic hyperthermia  

Science.gov (United States)

We demonstrate a facile approach for the synthesis of folate-conjugated luminescent iron oxide nanoparticles (FLIONs). XRD and TEM analyses reveal the formation of highly crystalline single-phase Fe3O4 nanoparticles of size about 10 nm. The conjugation of folate receptor (folic acid, FA) and luminescent molecule (fluorescein isothiocyanate, FITC) onto the surface of nanoparticles was evident from FTIR and UV-visible spectroscopy. These FLIONs show good colloidal stability, high magnetic field responsivity and excellent self-heating efficacy. Specifically, a new class of magnetic nanoparticles has been fabricated, which can be used as an effective heating source for hyperthermia.

Barick, K. C.; Rana, Suman; Hassan, P. A.

2014-04-01

52

Synthesis and surface properties of magnetite (Fe3O4) nanoparticles infiltrated into porous silicon template  

Science.gov (United States)

The synthesis and surface properties of a composite material consisting of porous silicon/magnetite nanoparticles (PSi/Fe3O4 NPs) are demonstrated. PSi layers with intermediate pore size (˜100 nm) are prepared by electrochemical porosification of n-type Si wafer in a hydrofluoric acid-containing oxidizing agent and surfactant. The intrinsically luminescent PSi templates are infiltrated with ferromagnetic Fe3O4 NPs grown by a simple hydrothermal approach with average sizes ranging from 8 to 30 nm. The photoluminescence intensity of magnetic nanocomposite was enhanced after Fe3O4 loading, probably due to the recombination of photoexcited carriers within the nanocrystallites. Magnetization measurement for the nanocomposites indicated that the magnetic nanoparticles retain their ferromagnetic characteristic at room temperature. The nanocomposites have been characterized by various techniques including, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and magnetic measurements. The biocompatibility of both components and the ability to tailor the magnetic properties of the composite might be useful for magnetic and biomedical applications.

Harraz, Farid A.

2013-12-01

53

The double-effect mechanism between Fe3O4 nanoparticles and MSA-capped CdTe QDs  

International Nuclear Information System (INIS)

Water-soluble mercaptosuccinic acid (MSA)-capped CdTe quantum dots (QDs) of two sizes and superparamagnetic Fe3O4 nanoparticles have been synthesized and used to investigate the effect of the mechanism of Fe3O4 nanoparticles on the fluorescence intensity of QDs. In the presence of a low concentration of Fe3O4 nanoparticles, the CdTe QDs with smaller particle size exhibit fluorescence quenching while fluorescence enhancement of CdTe QDs with larger particle size was observed, and the fluorescence intensity changes with the excitation wavelength and the concentration of Fe3O4 nanoparticles. The mechanism study shows that there is a double-effect between the Fe3O4 and CdTe QDs: one is the fluorescence quenching effect due to Fe3O4 strong absorption of excitation and emission light, the other is the fluorescence enhancement effect resulting from a localized electromagnetic field caused by the absorption of exciting light. The fluorescence of CdTe QDs with lower concentration of Fe3O4 nanoparticles was determined via the synergy of the double-effect. To our best knowledge, this is the first systematic study on the interaction between Fe3O4 nanoparticles and CdTe QDs, which finds the fluorescence enhancement effect in the presence of low concentration of Fe3O4. - Highlights: ? Interaction of Fe3O4 nanoparticles of CdTe QDs. ? Fluorescence intensity of different size QDs shows quenching or enhancement. ? Double-effect mechanism of fluorescence enhancement and fluorescence quenching.

2012-09-01

54

Preparation and properties of bio-compatible magnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

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 the ethylenediamine blocked activated residual groups efficiently, hence enhancing the attachment of biotin for probing the avidin

2006-09-01

55

Synthesis and characterization of Fe3O4 nanoparticles with perspectives in biomedical applications  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Nowadays the use of magnetic nanoparticles (MNP) in medical applications has exceeded expectations. In molecular imaging, MNP based on iron oxide coated with appropriated materials have several applications in vitro and in vivo studies. For applications in nanobiotechnology these MNP must present so [...] me characteristics such as size smaller than 100 nanometers, high magnetization values, among others. Therefore the MNP have physical and chemical properties that are specific to certain studies which must be characterized for quality control of the nanostructured material. This study presents the synthesis and characterization of MNP of magnetite (Fe3O4) dispersible in water with perspectives in a wide range of biomedical applications. The characterization of the colloidal suspension based on MNP stated that the average diameter is (12.6±0.2) nm determined by Transmission Electron Microscopy where the MNP have the crystalline phase of magnetite (Fe3O4) that was identified by Diffraction X-ray and confirmed by Mössbauer Spectroscopy. The blocking temperature of (89±1) K, Fe3O4 MNP property, was determined from magnetic measurements based on the Zero Field Cooled and Field Cooled methods. The hysteresis loops were measured at different temperatures below and above blocking temperature. The magnetometry determined that the MNP showed superparamagnetic behavior confirmed by ferromagnetic resonance.

Javier Bustamante, Mamani; Lionel Fernel, Gamarra; Giancarlo Espósito de Souza, Brito.

56

Umbelliprenin-coated Fe3O4 magnetite nanoparticles: Antiproliferation evaluation on human Fibrosarcoma cell line (HT-1080)  

International Nuclear Information System (INIS)

The potential applications of Fe3O4 magnetite nanoparticles (MNPs) in nanomedicine as drug delivery systems are well known. In this study we prepared umbelliprenin-coated Fe3O4 MNPs and evaluated the antiproliferative effect of combination in vitro. After synthesis of Fe3O4 MNPs, particles were characterized by transmission electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction spectroscopy techniques. The natural candidate compound - umbelliprenin- was isolated and identified and umbelliprenin-coated Fe3O4 MNPs were prepared, using precipitation method. The surface chemistry of umbelliprenin-coated Fe3O4 MNPs as well as their thermal decomposition characteristics was examined using Fourier transform infrared spectroscopy and Thermogravimetric Analyzer equipment, respectively. HT-1080 cells were cultured until the logarithmic phase of growth, and MTT assay was successfully carried out to evaluate the possible cytotoxic effects of umbelliprenin-coated Fe3O4 MNPs in viable cells in vitro. The results demonstrated that umbelliprenin has moderate antiproliferative effects with IC50 value of 50 ?g/mL. However, the combination of umbelliprenin and Fe3O4 MNPs showed the IC50 value of 9 ?g/mL. In other words, cell proliferation decreased to the remarkably-low proportion of 45% after treating cells with umbelliprenin-coated Fe3O4 MNPs. This suggests that with the aid of nanoparticles as carriers, natural products may have even broader range of medical applications in future.

2010-08-30

57

Fe3O4 magnetic nanoparticles/reduced graphene oxide nanosheets as a novel electrochemical and bioeletrochemical sensing platform.  

Science.gov (United States)

We have developed Fe3O4 magnetic nanoparticles/reduced graphene oxide nanosheets modified glassy carbon (Fe3O4/r-GO/GC) electrode as a novel system for the preparation of electrochemical sensing platform. Decorating Fe3O4 nanoparticles on graphene sheets was performed via a facile one-step chemical reaction strategy, where the reduction of GO and the in-situ generation of Fe3O4 nanoparticles occurred simultaneously. Characterization of as-made nanocomposite using X-ray diffraction (XRD), transmission electron microscopy (TEM) and alternative gradient force magnetometry (AGFM) clearly demonstrate the successful attachment of monodisperse Fe3O4 nanoparticles to graphene sheets. Electrochemical studies revealed that the Fe3O4/r-GO/GC electrode possess excellent electrocatalytic activities toward the low potential oxidation of NADH (0.05 V vs. Ag/AgCl) as well as the catalytic reduction of O2 and H2O2 at reduced overpotentials. Via immobilization of lactate dehydrogenase (LDH) as a model dehydrogenase enzyme onto the Fe3O4/r-GO/GC electrode surface, the ability of modified electrode for biosensing lactate was demonstrated. In addition, using differential pulse voltammetry (DPV) to investigate the electrochemical oxidation behavior of ascorbic acid (AA), dopamine (DA) and uric acid (UA) at Fe3O4/r-GO/GC electrode, the high electrocatalytic activity of the modified electrode toward simultaneous detection of these compounds was indicated. Finally, based on the strong electrocatalytic action of Fe3O4/r-GO/GC electrode toward both oxidation and reduction of nitrite, a sensitive amperometric sensor for nitrite determination was proposed. The Fe3O4/r-GO hybrid presented here showing favorable electrochemical features may hold great promise to the development of electrochemical sensors, molecular bioelectronic devices, biosensors and biofuel cells. PMID:23708810

Teymourian, Hazhir; Salimi, Abdollah; Khezrian, Somayeh

2013-11-15

58

Functionalized Fe3O4@Au superparamagnetic nanoparticles: in vitro bioactivity  

Science.gov (United States)

The interaction of nanoparticles with cells has been a focus of interest during the past decade. We report the fabrication and characterization of hydrosoluble Fe3O4@Au nanoparticles functionalized with biocompatible and fluorescent molecules and their interaction with cell cultures by visualizing them with confocal microscopy. Gold covered iron oxide nanoparticles were synthesized by reducing metal salts in the presence of oleylamine and oleic acid. The functionalization of these particles with an amphiphilic polymer provides a water soluble corona as well as the possibility to incorporate different molecules relevant for bio-applications such as poly(ethylene glycol), glucose or a cadaverine derived dye. The particle size, and the presence of polymer layers and conjugated molecules were characterized and confirmed by transmission electron microscopy, thermogravimetric measurements and infrared spectroscopy. A complete magnetic study was performed, showing that gold provides an optimum coating, which enhances the superparamagnetic behaviour observed above 10-15 K in this kind of nanoparticle. The interaction with cells and the cytotoxicity of the Fe3O4@Au preparations were determined upon incubation with the HeLa cell line. These nanoparticles showed no cytotoxicity when evaluated by the MTT assay and it was demonstrated that nanoparticles clearly interacted with the cells, showing a higher level of accumulation in the cells for glucose conjugated nanoparticles.

Salado, J.; Insausti, M.; Lezama, L.; Gil de Muro, I.; Moros, M.; Pelaz, B.; Grazu, V.; de la Fuente, J. M.; Rojo, T.

2012-08-01

59

Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications  

International Nuclear Information System (INIS)

The utility and promise of magnetic nanoparticles (MagNPs) for biomedicine rely heavily on accurate determination of the particle diameter attributes. While the average functional size and size distribution of the magnetic nanoparticles directly impact the implementation and optimization of nanobiotechnology applications in which they are employed, the determination of these attributes using electron microscopy techniques can be time-consuming and misrepresentative of the full nanoparticle population. In this work the average particle diameter and distribution of an ensemble of Fe3O4 ferrimagnetic nanoparticles are determined solely from temperature-dependent magnetization measurements; the results compare favorably to those obtained from extensive electron microscopy observations. The attributes of a population of biocompatible Fe3O4 nanoparticles synthesized by a thermal decomposition method are obtained from quantitative evaluation of a model that incorporates the distribution of superparamagnetic blocking temperatures represented through thermomagnetization data. The average size and size distributions are determined from magnetization data via temperature-dependent zero-field-cooled magnetization. The current work is unique from existing approaches based on magnetic measurement for the characterization of a nanoparticle ensemble as it provides both the average particle size as well as the particle size distribution. - Highlights: ? Size distribution of nanoparticles determined via thermomagnetic response. ? Calculated distribution exhibited reasonable agreement with electron microscopy. ? Effective anisotropy constant determined is by scaling of distribution function. ? Minimizes need for particle sizing using electron microscopy. ? Facile alternative to conventional size determination techniques.

2011-09-01

60

Gum arabic modified Fe3O4 nanoparticles cross linked with collagen for isolation of bacteria  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Multifunctional magnetic nanoparticles are important class of materials in the field of nanobiotechnology, as it is an emerging area of research for material science and molecular biology researchers. One of the various methods to obtain multifunctional nanomaterials, molecular functionalization by attaching organic functional groups to nanomagnetic materials is an important technique. Recently, functionalized magnetic nanoparticles have been demonstrated to be useful in isolation/detection of dangerous pathogens (bacteria/viruses for human life. Iron (Fe based material especially FePt is used in the isolation of ultralow concentrations (2 cfu/ml of bacteria in less time and it has been demonstrated that van-FePt may be used as an alternative fast detection technique with respect to conventional polymerase chain reaction (PCR method. However, still further improved demonstrations are necessary with interest to biocompatibility and green chemistry. Herein, we report the synthesis of Fe3O4 nanoparticles by template medication and its application for the detection/isolation of S. aureus bacteria. Results The reduction of anhydrous Iron chloride (FeCl3 in presence of sodium borohydride and water soluble polyelectrolyte (polydiallyldimethyl ammonium chloride, PDADMAC produces black precipitates. The X-ray diffraction (XRD, XPS and TEM analysis of the precipitates dried at 373 K demonstrated the formation of nanocrystalline Fe3O4. Moreover, scanning electron microscopy (SEM showed isolated staphylococcous aureus (S. aureus bacteria at ultralow concentrations using collagen coated gum arabic modified iron oxide nanoparticles (CCGAMION. Conclusion We are able to synthesize nanocrystalline Fe3O4 and CCGAMION was able to isolate S. aureus bacteria at 8-10 cfu (colony forming units/ml within ~3 minutes.

Chittor Raghuraman

2010-12-01

 
 
 
 
61

Electrical and Magnetic Properties of Polymer Electrolyte PVA.LiOH Dispersed by Fe3O4 Nanoparticles  

Science.gov (United States)

Nanocomposite magnetic polymer electrolyte based on poly (vinyl alcohol) (PVA) with lithium hydroxide (LiOH) dispersed by magnetite (Fe3O4) nanoparticle as inorganic filler were prepared by using an in-situ method. Ions carriers were inserted during the growth of the nanoparticles that had been contributed by a precursor. The effect upon the addition of Fe3O4 nanoparticles on the ionic conductivity of the composite polymer electrolytes was investigated, and it was proven that the ionic conductivity had been enhanced. Maximum conductivity was obtained upon addition of Fe3O4 nanoparticles, i.e. 1.81×10-3S.cm-1. The magnetic properties of nanocomposite magnetic polymer electrolyte were observed by magnetic susceptibility studies. The magnetic susceptibility data revealed that polymer electrolyte PVA.LiOH dispersed by Fe3O4 nanoparticle was found predominantly ferrimagnetism.

Aji, Mahardika Prasetya; Rahmawati, Rahmawati; Masturi, Masturi; Bijaksana, Satria; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin

2011-12-01

62

COMMENT: Comment on 'Preparation and antibacterial activity of Fe3O4@Ag nanoparticles'  

Science.gov (United States)

The fabrication of nanocomposite materials with a metal-oxide@nobel-metal structure represents a challenge both from the theoretical and experimental points of view. This challenge is connected with a complicated mechanism of formation of these nanocomposite materials. In the paper by Gong et al (2007 Nanotechnology 18 285604), the authors tried to solve this problem but the suggested mechanism is rather improbable. This improbability derived from the found discrepancy in the material balance of reactants/products. Therefore this comment is devoted to evaluation of this discrepancy of the Fe3O4@Ag nanoparticle preparation and suggestion of another possible mechanism.

Kvítek, Libor; Soukupova, Jana

2009-01-01

63

Comment on 'Preparation and antibacterial activity of Fe3O4-Ag nanoparticles'  

International Nuclear Information System (INIS)

The fabrication of nanocomposite materials with a metal oxide-nobel metal structure represents a challenge both from the theoretical and experimental points of view. This challenge is connected with a complicated mechanism of formation of these nanocomposite materials. In the paper by Gong et al (2007 Nanotechnology 18 285604), the authors tried to solve this problem but the suggested mechanism is rather improbable. This improbability derived from the found discrepancy in the material balance of reactants/products. Therefore this comment is devoted to evaluation of this discrepancy of the Fe3O4-Ag nanoparticle preparation and suggestion of another possible mechanism. (comment)

2009-01-14

64

Influences of different synthesis conditions on properties of Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Magnetic nanoparticles of Fe3O4 had been fabricated through hydrothermal reaction by using sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as a surfactant and hydrazine hydrate (N2H4.H2O) as a reductant. The influences of different concentrations of AOT and N2H4.H2O on the nanoparticles were investigated; moreover, the different reaction temperatures and time were also analyzed. Their structure and morphology were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR). Furthermore, magnetic properties of the products were studied by vibrating sample magnetometer (VSM). The crystallite size of the samples was calculated using Debye-Scherrer equation. It was found that the as-prepared nanoparticles had been modified by using surfactant during the synthesis process. The amount of AOT and N2H4.H2O, the reaction temperature and time had effects on the size, the dispersal and the magnetic properties of the particles. The well-dispersed magnetic Fe3O4 nanoparticles with better size distribution could be prepared at 150 deg. C for 10 h when the concentrations of AOT and N2H4.H2O were 0.10 M and 20% (v/v), respectively. Besides, possible mechanisms related to the effects were also discussed

2009-01-15

65

Heat dissipation and magnetic properties of surface-coated Fe3O4 nanoparticles for biomedical applications  

Science.gov (United States)

In this study, the influence of surface coating on the magnetic and heat dissipation properties of Fe3O4 nanoparticles was investigated. Fe3O4 nanoparticles that ranged in size between (particle sizes of 20 and 30 nm) were coated with polyethylenimine (PEI), oleic acid, and Pluronic F-127. Surface coatings that were composed of thick layers of oleic acid and Pluronic F-127 reduced dipole interactions between the particles, and resulted in reduced coercivity and decreased Néel relaxation times. The ac magnetization measurements revealed that the heat dissipation of the PEI-coated Fe3O4 nanoparticles was induced by hysteresis loss and Brownian relaxation loss and that of the oleic-acid-coated Fe3O4 nanoparticles was mainly induced by hysteresis loss and Néel relaxation loss.

Tomitaka, Asahi; Ueda, Koji; Yamada, Tsutomu; Takemura, Yasushi

2012-10-01

66

Innovative synthesis of citrate-coated superparamagnetic Fe3O4 nanoparticles and its preliminary applications.  

Science.gov (United States)

In this study, we describe the development of a facile and effective route for the synthesis of Fe(3)O(4)-based T(1) contrast agent, which can be useful for in vivo magnetic resonance (MR) imaging. Citrate-coated Fe(3)O(4) nanoparticles (6 nm) with a narrow size distribution were synthesized by "one-pot green chemistry route" in diethylene glycol (DEG) solvent. The synthesized nanoparticles were characterized by different analytical techniques including XRD, TEM, HRTEM, and FTIR. At room temperature, nanoparticles exhibited superparamagnetic nature with high saturation magnetization. The longitudinal (r(1)) and transverse (r(2)) relaxivities were found to be 35.45 and 51.81 mM(-1)s(-1), respectively. Contrast agent developed by this method showed a relatively higher longitudinal relaxivity (r(1)) and the lowest relaxivity ratio (r(2)/r(1)=1.46) at 3T MR field. The anionic nature of citric acid facilitated non-specific internalization without impairment of cell viability and functionality. The in vitro studies showed both phagocitic and non-phagocytic uptake of these NPs. In vivo MR imaging of swine showed both T(1) and T(2) contrast effect. PMID:21513942

Srivastava, S; Awasthi, Rishi; Gajbhiye, Namdeo S; Agarwal, Vikas; Singh, Amit; Yadav, Abhishek; Gupta, Rakesh K

2011-07-01

67

Immobilization of Candida rugosa lipase on superparamagnetic Fe3O4 nanoparticles for biocatalysis in low-water media.  

Science.gov (United States)

A simple immobilization method for Candida rugosa lipase on superparamagnetic Fe3O4 nanoparticles is described. The Fe3O4 nanoparticles were coated with PEI and Candida rugosa lipase was adsorbed on these particles via electrostatic interactions. The immobilization resulted in marginal simultaneous purification. However, the immobilized preparation showed 110× higher transesterification activity in low-water media. It was also efficient in kinetic resolution of (±)-1-phenylethanol with eep of 99 % and E = 412 within 24 h. PMID:23934801

Mukherjee, Joyeeta; Solanki, Kusum; Gupta, Munishwar Nath

2013-01-01

68

Effect of interaction of magnetic nanoparticles of Fe3O4 and artesunate on apoptosis of K562 cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The present study evaluated whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) could enhance the activity of artesunate (ART), and to explore its potential mechanisms. Cytotoxicity of the copolymer of ART with MNPs-Fe3O4 on K562 cells was detected by MTT assay and the apoptosis rate of K562 cells was measured by flow cytometry. Protein expression levels of bcl-2, bax, bcl-rambo, caspase-3, and survivin in K562 cells were measured by Western blot. After being incubated with the copolymer...

Wang, Ying; Han, Yuxiang; Yang, Yingying; Yang, Jingci; Guo, Xiaonan; Zhang, Jingnan; Pan, Ling; Xia, Guohua; Chen, Baoan

2011-01-01

69

Magnetic nanoparticle of Fe3O4 and 5-bromotetrandrin interact synergistically to induce apoptosis by daunorubicin in leukemia cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Apoptosis is a common pathway that finally mediated the killing functions of anticancer drugs, which is an important cause of multidrug resistance (MDR). The aim of this study was to investigate the potential benefit of combination therapy with magnetic nanoparticle of Fe3O4 (MNP(Fe3O4)) and 5-bromotetrandrin (BrTet). Analysis of the apoptosis percentage showed that combination of daunorubicin (DNR) with either MNP(Fe3O4) or BrTet exerted a potent cytotoxic effect on K562/A02 cells, while MNP...

Chen, Baoan; Cheng, Jian; Shen, Mingfang; Gao, Feng; Xu, Wenlin; Shen, Huilin; Ding, Jiahua; Gao, Chong; Sun, Qian; Sun, Xinchen; Cheng, Hongyan; Li, Guohong; Chen, Wenji; Chen, Ningna; Liu, Lijie

2009-01-01

70

Preparation of stable magnetic nanofluids containing Fe3O4@PPy nanoparticles by a novel one-pot route  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy) nanoparticles (NPs) were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit) was used as the reducing reagent to form Fe3O4 NPs. The as-prepared nanofluid can keep long-term stability. The Fe3O4@PPy NPs can still keep dispersing well after the nanofluid has been standing for 1 month and no sedimen...

Zhao, Baobao; Nan, Zhaodong

2011-01-01

71

Fabrication of Docetaxel Surfaced Fe3O4 Magnetite Nanoparticles and their Cytotoxicity on 4 T1 Breast Cancer Cells  

Directory of Open Access Journals (Sweden)

Full Text Available Background:In the recent years, there is an increasing attention to the using of Fe3O4 magnetite nanoparticles (MNPs as drug delivery systems. Application of this nanoparticles could profit advantages of nanomedicine to enhance biological activity of pharmaceutical ingredients. Methods:Fe3O4 MNPs were synthesised by a chemical method and characterized by transmission electron microscopy and energy-dispersive spectroscopy techniques. In the next step, docetaxel-coated Fe3O4 MNPs were prepared, using percipitation method. The surface chemistry of docetaxel-coated Fe3O4 MNPs as well as their thermal decomposition characteristics were examined using fourier transform infrared spectroscopy and thermogravimetric analyzer equipment, respectively. The cytotoxicity assay was conducted on 4 T1 breast cancer carsinoma by MTT assay to evaluate the possible in vitro antiproliferative effects of docetaxel-coated Fe3O4 MNPs. Results:During precipitation process, docetaxel molecules were precipitated on the surface of Fe3O4 MNPs by the ratio of 3:100 w/w which indicates that each milligram of coated Fe3O4 MNPs averagely contained 30 mug pure docetaxel compound. Docetaxel showed aniproliferative effects against mentioned cell line. The higestest concentartion of docetaxel (80 mug/ml caused about 80% cell death. However, the results demostarted that much lower amounts of docetaxel will be needed in combination of Fe3O4 MNPs to produce the potent antiproliferative effect compared to docetaxel alone. Dose response cytotoxicity assay of docetaxel-coated Fe3O4 MNPs against 4 T1 breast cancer cells showed that lower amount of docetaxel (0.6 mug/ml can exhibit higher cytotoxic effect against this cancer cell line (90% cell death.

MH Yazdi

2012-08-01

72

Preparation of stable magnetic nanofluids containing Fe3O4@PPy nanoparticles by a novel one-pot route  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy nanoparticles (NPs were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit was used as the reducing reagent to form Fe3O4 NPs. The as-prepared nanofluid can keep long-term stability. The Fe3O4@PPy NPs can still keep dispersing well after the nanofluid has been standing for 1 month and no sedimentation is found. The polymerization reaction of the pyrrole monomers took place with Fe3+ ions as the initiator, in which these Fe3+ ions remained in the solution adsorbed on the surface of the Fe3O4 NPs. Thus, the core-shell NPs of Fe3O4@PPy were obtained. The particle size of the as-prepared Fe3O4@PPy can be easily controlled from 7 to 30 nm by the polymerization reaction of the pyrrole monomers. The steric stabilization and weight of the NPs affect the stability of the nanofluids. The as-prepared Fe3O4@PPy NPs exhibit superparamagnetic behavior.

Zhao Baobao

2011-01-01

73

The effect of Fe3O4 nanoparticles on the thermal conductivities of various base fluids.  

Science.gov (United States)

Conventional heat transfer fluids have intrinsically poor heat transfer properties compared to solids. Enhancing the efficiency of heat transfer is of great interest for various industrial applications. Suspending solid particles in a fluid increases the thermal conductivity of the resulting suspension and enhances the heat transfer properties. In this work, changes in thermal conductivities of fluids upon the addition of magnetic nanoparticles have been investigated. Fe(3)O(4) nanoparticles are synthesized using different synthesis methods and are suspended in various oils. The effect of the base fluid and the type of magnetic particle on the thermal conductivity is investigated in detail. Up to 28% increase in the thermal conductivity is obtained with 2.5 wt% magnetic particles in hexane. The thermal conductivity enhancement is found to depend on the particle concentration, method of preparation and base fluid. The enhancements obtained are higher than those estimated using any theoretical model present in the literature. PMID:21659690

Altan, Cem L; Bucak, Seyda

2011-07-15

74

The effect of Fe3O4 nanoparticles on the thermal conductivities of various base fluids  

International Nuclear Information System (INIS)

Conventional heat transfer fluids have intrinsically poor heat transfer properties compared to solids. Enhancing the efficiency of heat transfer is of great interest for various industrial applications. Suspending solid particles in a fluid increases the thermal conductivity of the resulting suspension and enhances the heat transfer properties. In this work, changes in thermal conductivities of fluids upon the addition of magnetic nanoparticles have been investigated. Fe3O4 nanoparticles are synthesized using different synthesis methods and are suspended in various oils. The effect of the base fluid and the type of magnetic particle on the thermal conductivity is investigated in detail. Up to 28% increase in the thermal conductivity is obtained with 2.5 wt% magnetic particles in hexane. The thermal conductivity enhancement is found to depend on the particle concentration, method of preparation and base fluid. The enhancements obtained are higher than those estimated using any theoretical model present in the literature.

2011-07-15

75

Characterization of superparamagnetic Fe3O4 nanoparticles by fluxgate magnetorelaxometry for use in biomedical applications  

Science.gov (United States)

We have investigated the magnetorelaxometry (MRX) of various Fe3O4 nanoparticle suspensions utilizing a differential fluxgate setup. To estimate the distribution of the hydrodynamic size of the magnetic nanoparticles (MNPs) with organic shell, the cluster moment superposition model is applied. On a sample series of MNPs from the same batch diluted in water-glycerine mixtures of varying viscosity, it is demonstrated that the model is suited for the estimation of the distribution of the hydrodynamic size of MNPs and clusters. Since a MRX measurement lasts only a few seconds, it is also highly suited to study the aggregation kinetics. This is demonstrated on MNPs with silica shell suspended in 5% phosphate-buffered saline solution.

Ludwig, F.; Heim, E.; Schilling, M.; Enpuku, K.

2008-04-01

76

UCST-like hybrid PAAm-AA/Fe3O4 microgels. Effect of Fe3O4 nanoparticles on morphology, thermosensitivity and elasticity.  

Science.gov (United States)

The incorporation of metal oxide nanoparticles into microgels forming hybrid systems gives additional functionalities to the system and widens the field of potential application in biomedicine, biotechnology, and other fields. In particular, there have been very few investigations regarding UCST-like hybrid microgels. In connection with this, we report the preparation of UCST-like hybrid microgels of magnetite nanoparticles (Fe(3)O(4)) encapsulated in poly(acrylamide-acrylic acid) microgel matrix via an inverse emulsion polymerization method. The key factor in the preparation of hybrid microgels is the need to divide in two the aqueous phase of the emulsion and feed them separately in order to avoid the aggregation of magnetic nanoparticles prior to polymerization reaction. The morphology, size, and spherical shape of hybrid microgels are determined by scanning electron microscopy. The encapsulation of magnetite nanoparticles within the polymer matrix is confirmed by transmission electron microscopy. Dynamic light scattering is employed to study both the swelling UCST-like behavior and the surface charge of the hybrid microgels. Swelling measurements confirm that the incorporation of magnetite does not affect the thermosensitivity of the system. In order to highlight the rheological behavior that can affect the final potential applications of these hybrid systems, a deep study of the viscoelastic properties is carried out by means of an oscillatory rheometer. The dependence of G' and G'' of the microgel dispersions with the frequency suggests a gel-like behavior and hence the occurrence of structural organization. In order to understand this structure formation and the influence of the magnetite in the interaction between hybrid microgels, scaling theory was applied. In terms of rheology, the addition of magnetite leads to a change in the interaction between hybrid microgels giving rise to an increase in the elasticity of the system. PMID:21630668

Echeverria, Coro; Mijangos, Carmen

2011-07-01

77

Immobilization of Pycnoporus sanguineus laccase on copper tetra-aminophthalocyanine-Fe(3)O(4) nanoparticle composite.  

Science.gov (United States)

A magnetic nanoparticle composite of CuTAPc (copper tetra-aminophthalocyanine)-Fe(3)O(4) was prepared by in situ complexation and was characterized by FTIR (Fourier-transform IR) spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FESEM (field emission scanning electron microscopy) micrograph and hysteresis loop. The results showed that CuTAPc formed the covering layer on the surface of the composite. Using glutaraldehyde, laccase was covalently attached to the surface of the composite. When white-rot-fungus (Pycnoporus sanguineus) laccase was immobilized on the CuTAPc-Fe(3)O(4) nanoparticle composite in PBS, the optimal reaction pH was 5.0 and the optimal temperature was 0 degrees C. When 2.0 mg/ml laccase solution was used, the immobilization yield was 20%. The activity, K(m), k(cat)/K(m) and V(max) values of the immobilized laccase were 1.43 units/mg, 2.38 x 10(-5) mol/l, 2.1 x 10(3) mol(-1) x s(-1) x l and 1.19 x 10(-6) mol x l(-1) /x min(-1) respectively. The system exhibited maximum enzyme activity at pH 3.0 and at 45 degrees C. After storage at 4 degrees C for 1 month, the residual activity of the immobilized laccase was 85% of its initial activity, while that of free laccase was only 30%. During 240 min incubation at 55 degrees C, the activity of immobilized laccase quickly increased to a maximum after 150 min and then decreased to 95% in the next 90 min, while the activity of the free enzyme decreased monotonically to 28%. After five consecutive operations, the immobilized laccase still retained 80% of its initial activity. PMID:16420188

Huang, Jun; Xiao, Haiyan; Li, Bin; Wang, Juntao; Jiang, Desheng

2006-05-01

78

Cytotoxicity of Fe3O4/Au composite nanoparticles loaded with doxorubicin combined with magnetic field.  

Science.gov (United States)

GoldMag (Fe3O4/Au) nanoparticles have the advantages of both magnetic response in an external magnetic field and the immobilization of molecules on their surface in a single step. The cytotoxicities of GoldMag nanoparticles and GoldMag nanoparticles loaded with doxorubicin (Dox-GoldMag) combined with an external magnetic field were tested in vitro on HepG2 malignant tumor cells. The results showed that cell viability remained above 92% when using GoldMag nanoparticles at a concentration as high as 2.0 mg/ml, suggesting the biocompatibility of the nanoparticles. The IC50 (0.731 microg/ml) of the Dox-GoldMag group was higher than that (0.522 microg/ml) of the Dox group (P Dox-GoldMag group combined with a magnetic field had an obviously increased inhibition rate for the HepG2 cell line and the IC50 was lower than that of the Dox group (0.421 microg/ml). These results indicated that GoldMag nanoparticles loaded with doxorubicin combined with a permanent magnetic field are more cytotoxic and could be a potential targeted drug delivery system. PMID:20662318

Chao, Xu; Shi, Feng; Zhao, Ying-Yong; Li, Ke; Peng, Ming-Li; Chen, Chao; Cui, Ya-Li

2010-07-01

79

Correlation of structural and magnetic properties of Fe3O4 nanoparticles with their calorimetric and magnetorheological performance  

International Nuclear Information System (INIS)

Magnetic particles based on Fe3O4 were prepared by means of the microwave solvothermal method under different reaction conditions with the intention of their utilization as a mediator in magnetic hyperthermia and material for reducing blood flow in the tumor area. The synthesized particles were characterized in terms of their structure, size, shape, and magnetic properties with an emphasis on the correlation between particle morphology and magnetic properties. Most importantly, their heat development when exposed to an alternating magnetic field was determined, as well as the rheological behavior of their suspensions under static magnetic field. Reasonable heat development and substantial flow resistance under the effect of magnetic field indicate their potential for applications such as hyperthermia mediators or substances for temporary embolization. - Highlights: ? Fe3O4 nanoparticles were obtained by microwave-assisted synthesis ? Nucleation agents affect morphological and magnetic properties of nanoparticles. ? Aqueous ammonia nucleated Fe3O4 nanoparticles show high heating ability in AC magnetic field due to Neel relaxation. ? Suspension of Fe3O4 in silicone oil demonstrates flow resistance under DC magnetic field caused by chain formation. ? Fe3O4 nanoparticles has potential as a hyperthermia mediator and substance for temporary embolization.

2013-01-01

80

Magnetic fluid based on Fe3O4 nanoparticles: Preparation and hyperthermia application  

Science.gov (United States)

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

 
 
 
 
81

Magnetic fluid based on Fe3O4 nanoparticles: Preparation and hyperthermia application  

International Nuclear Information System (INIS)

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 to 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 deg. C.

2009-09-01

82

Fe3O4/Salicylic acid nanoparticles behavior on chick CAM vasculature  

International Nuclear Information System (INIS)

A modified ferrite co-precipitation synthesis was used to obtain core–shell Fe3O4/salicylic acid magnetic nanoparticles (Sa-MNP) with well-dispersed aqueous solution properties. The newly developed iron oxide nanoparticles properties were investigated with X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, and laser light scattering for their characteristic establishment. The resulting Sa-MNPs have spherical morphology, homogenous size distribution around 60 nm (35 nm FWHM), and a 67 mV Zeta potential value (15.5 mV STDV). In vivo biocompatibility and intravascular behavior of the 60 nm diameter size range synthesized nanoparticles were evaluated on chick chorioallantoic membrane model. The results show a reversible and good controlled intravascular accumulation under static magnetic field, a low risk of embolisation with nanoparticle aggregates detached from venous intravascular nanoblocked areas, a persistent blocking of the arterioles and dependent capillaries network, a good circulating life time and biocompatibility. The beneficial effects of salicylic acid (SA) and in vivo demonstrated capacity of Sa-MNPs to cutoff regional vascular supply under static magnetic field control suggest a possible biomedical application of these MNPs in targeted cancer therapy through magnetic controlled blood flow nanoblocking mechanism

2013-08-01

83

A novel platform of hemoglobin on core-shell structurally Fe3O4-Au nanoparticles and its direct electrochemistry  

International Nuclear Information System (INIS)

Research highlights: ? In recent years, immobilization of biomolecule onto nanomaterials, which could be utilized in the investigation of biomolecule reactions and the preparations of the biosensors, has attracted much research attention. A novel platform, which hemoglobin (Hb) was immobilized on core-shell structurally Fe3O4/Au nanoparticles (simplified as Fe3O4-Au NPs) modified glassy carbon electrode (GCE), has been developed for fabricating the third biosensors in this paper. ? Magnetic NPs stand out because of their added properties. However, naked Fe3O4 NPs are very sensitive to oxidation because of their high chemical reactivity and being prone to aggregate. Those defects limit their further applications. We presented a simple approach to synthesize Au modified Fe3O4 NPs with core-shell structure, which was characterized by transmission electron microscopy, scanning electron microscope, energy dispersive spectra and UV-vis spectroscopy. ? The thermodynamics, dynamics and catalysis properties of Hb immobilized on Fe3O4-Au NPs were discussed by UV-visible spectrum, electrochemical impedance spectroscopy, electrochemical quartz crystal microbalance technique and cyclic voltammetry. The electrocatalytic behaviors of the immobilized Hb on Fe3O4-Au NPs were applied for the determination of hydrogen peroxide, oxygen and trichloroacetic acid. The possible functions of Fe3O4 core and Au shell as a novel platform for achieving Hb direct electrochemistry were also discussed, respectively. - Abstract: A novel platform, which hemoglobin (Hb) was immobilized on core-shell structurally Fe3O4/Au nanoparticles (simplified as Fe3O4-Au NPs) modified glassy carbon electrode (GCE), has been developed for fabricating the third biosensors. Fe3O4-Au NPs, characterized using transmission electron microscope (TEM), scanning electron microscope (SEM) and energy dispersive spectra (EDS), were coated onto GCE mediated by chitosan so as to provide larger surface area for anchoring Hb. The thermodynamics, dynamics and catalysis properties of Hb immobilized on Fe3O4-Au NPs were discussed by UV-visible spectrum (UV-vis), electrochemical impedance spectroscopy (EIS), electrochemical quartz crystal microbalance technique (EQCM) and cyclic voltammetry (CV). The electrochemical parameters of Hb on Fe3O4-Au NPs modified GCE were further carefully calculated with the results of the effective working area as 3.61 cm2, the surface coverage concentration (?) as 1.07 x 10-12 mol cm-2, the electron-transfer rate constant (Ks) as 1.03 s-1, the number of electron transferred (n) as 1.20 and the standard entropy of the immobilized Hb (?S0') as calculated to be -104.1 J mol-1 K-1. The electrocatalytic behaviors of the immobilized Hb on Fe3O4-Au NPs were applied for the determination of hydrogen peroxide (H2O2), oxygen (O2) and trichloroacetic acid (TCA). The possible functions of Fe3O4 core and Au shell as a novel platform for achieving Hb direct electrochemistry were discussed, respectively.

2011-03-30

84

A facile route to sonochemical synthesis of magnetic iron oxide (Fe3O4) nanoparticles  

International Nuclear Information System (INIS)

A facile sonochemical approach was applied for the large scale synthesis of iron oxide magnetic nanoparticles (NPs) using inexpensive and non-toxic metal salts as reactants. The as-prepared magnetic iron oxide NPs has been characterized by XRD, TEM, EDS, and VSM. X-ray diffraction (XRD) and EDS analysis revealed that Fe3O4 NPs have been successfully synthesized in a single reaction by this simple method. Transmission electron microscopy (TEM) data demonstrated that the particles were narrow range in size distribution with 11 nm average particle size. Moreover, TEM measurements also show that the synthesized nanoparticles are almost spherical in shape. The magnetization curve from vibrating sample magnetometer (VSM) measurement shows that as-synthesized NPs were nearly superparamagnetic in magnetic properties with very low coercivity, and magnetization values were 80 emu/g, which is very near to the bulk value of iron oxide. The estimated value of mass susceptibility of as-synthesized nanoparticles is Xg = 5.71 x 10-4 m3/kg.

2011-09-30

85

Synergistic effect of magnetic nanoparticles of Fe3O4 with gambogic acid on apoptosis of K562 leukemia cells  

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Gambogic acid (GA) has a significant anticancer effect on a wide variety of solid tumors. Recently, many nanoparticles have been introduced as drug-delivery systems to enhance the efficiency of anticancer drug delivery. The aim of this study was to investigate the potential benefit of combination therapy with GA and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4). The proliferation of K562 cells and their cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by micro...

Chen, Baoan; Liang, Yiqiong; Wu, Weiwei; Cheng, Jian; Xia, Guohua; Gao, Feng; Ding, Jiahua; Gao, Chong; Shao, Zeye; Li, Guohong; Chen, Wenji; Xu, Wenlin; Sun, Xinchen; Liu, Lijie; Li, Xiaomao

2009-01-01

86

Reversal of multidrug resistance by cisplatin-loaded magnetic Fe3O4 nanoparticles in A549/DDP lung cancer cells in vitro and in vivo  

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The purpose of this study was to explore whether magnetic Fe3O4 nanoparticles (Fe3O4-MNP) loaded with cisplatin (Fe3O4-MNP-DDP) can reverse DDP resistance in lung cancer cells and to investigate mechanisms of multidrug resistance in vitro and in vivo. MTT assay showed that DDP inhibited both A549 cells and DDP-resistant A549 cells in a time-dependent and dose-dependent manner, and that this inhibition was enhanced by Fe3O4-MNP. An increased rate of apoptosis was detected in the Fe3O4-MNP-DDP ...

Li, Ke; Chen, Baoan; Xu, Lin; Feng, Jifeng; Xia, Guohua; Cheng, Jian; Wang, Jun; Gao, Feng; Wang, Xuemei

2013-01-01

87

Fe3O4/Au magnetic nanoparticle amplification strategies for ultrasensitive electrochemical immunoassay of alfa-fetoprotein  

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Full Text Available Ning Gan1*, Haijuan Jin1*, Tianhua Li1, Lei Zheng21The State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo, 2Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China *Both authors contributed equally to this workBackground: The purpose of this study was to devise a novel electrochemical immunosensor for ultrasensitive detection of alfa-fetoprotein based on Fe3O4/Au nanoparticles as a carrier using a multienzyme amplification strategy.Methods and results: Greatly enhanced sensitivity was achieved using bioconjugates containing horseradish peroxidase (HRP and a secondary antibody (Ab2 linked to Fe3O4/Au nanoparticles (Fe3O4/Au-HRP-Ab2 at a high HRP/Ab2 ratio. After a sandwich immunoreaction, the Fe3O4/Au-HRP-Ab2 captured on the electrode surface produced an amplified electrocatalytic response by reduction of enzymatically oxidized hydroquinone in the presence of hydrogen peroxide. The high content of HRP in the Fe3O4/Au-HRP-Ab2 could greatly amplify the electrochemical signal. Under optimal conditions, the reduction current increased with increasing alfa-fetoprotein concentration in the sample, and exhibited a dynamic range of 0.005–10 ng/mL with a detection limit of 3 pg/mL.Conclusion: The amplified immunoassay developed in this work shows good precision, acceptable stability, and reproducibility, and can be used for detection of alfa-fetoprotein in real samples, so provides a potential alternative tool for detection of protein in the laboratory. Furthermore, this immunosensor could be regenerated by simply using an external magnetic field.Keywords: Fe3O4/Au nanoparticles, alfa-fetoprotein, sandwich immunoassay, electrochemical immunosensor

Gan N

2011-12-01

88

Magnetic Fe3O4 nanoparticles and chemotherapy agents interact synergistically to induce apoptosis in lymphoma cells  

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The purpose of this study was to investigate the potential effects of combination therapy using magnetic nanoparticles of Fe3O4 (MNP-Fe3O4) and chemotherapeutic drugs on lymphoma cells. Proliferation, inhibition, and viability of Raji cells were detected by MTT and trypan blue exclusion. The percentage of cells undergoing apoptosis was detected by flow cytometry using fluorescein isothiocyanate-annexin V and propidium iodide staining. p53 and nuclear factor-?B (NF-?B) protein levels were me...

Jing, Hongmei; Wang, Jing; Yang, Ping; Ke, Xiaoyan; Xia, Guohua; Chen, Baoan

2010-01-01

89

Photoelectron diffraction study of Rh nanoparticles growth on Fe3O4/Pd(111) ultrathin film  

International Nuclear Information System (INIS)

Metallic nanoparticles (NPs) supported on oxides thin films are commonly used as model catalysts for studies of heterogeneous catalysis. Several 4d and 5d metal NPs (for example, Pd, Pt and Au) grown on alumina, ceria and titania have shown strong metal support interaction (SMSI), for instance the encapsulation of the NPs by the oxide. The SMSI plays an important role in catalysis and is very dependent on the support oxide used. The present work investigates the growth mechanism and atomic structure of Rh NPs supported on epitaxial magnetite Fe3O4(111) ultrathin films prepared on Pd(111) using the Molecular Beam Epitaxy (MBE) technique. The iron oxide and the Rh NPs were characterized using X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction and photoelectron diffraction (PED). The combined XPS and PED results indicate that Rh NPs are metallic, cover approximately 20 % of the iron oxide surface and show height distribution ranging 3–5 ML (monolayers) with essentially a bulk fcc structure.

2013-04-01

90

Magnetic Fe3O4@C nanoparticles as adsorbents for removal of amoxicillin from aqueous solution.  

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In the present study, powder activated carbon (PAC) combined with Fe(3)O(4) magnetite nanoparticles (MNPs) were used for the preparation of magnetic composites (MNPs-PAC), which was used as an adsorbent for amoxicillin (AMX) removal. The properties of magnetic activated carbon were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunaeur, Emmett and Teller and vibrating sample magnetometer. The operational factors affecting adsorption such as pH, contact time, adsorbent dosage, initial AMX concentration and temperature were studied in detail. The high surface area and saturation magnetization for the synthesized adsorbent were found to be 671.2 m(2)/g and 6.94 emu/g, respectively. The equilibrium time of the adsorption process was 90 min. Studies of adsorption equilibrium and kinetic models revealed that the adsorption of AMX onto MNPs-PAC followed Freundlich and Langmuir isotherms and pseudo-second-order kinetic models. The calculated values of the thermodynamic parameters, such as ?G°, ?H° and ?S° demonstrated that the AMX adsorption was endothermic and spontaneous in nature. It could be concluded that MNPs-PAC have a great potential for antibiotic removal from aquatic media. PMID:24434981

Kakavandi, Babak; Esrafili, Ali; Mohseni-Bandpi, Anoushiravan; Jonidi Jafari, Ahmad; Rezaei Kalantary, Roshanak

2014-01-01

91

Design, characterization and magnetic properties of Fe3O4-nanoparticle arrays coated with PEGylated-dendrimers  

International Nuclear Information System (INIS)

Graphical abstract: The preparation of magnetite Fe3O4 MNPs using the chemical co-precipitation method in presence of biocompatible PAMAM-based dendrimers with end-grafted ethylene glycol ethers is discussed. The magnetic peculiarities of the Fe3O4 MNPs were analyzed by SQUID VSM. Highlights: ? (Poly)ethylene glycol terminated (amidoamine)-based dendrimers are applied. ? Act as stabilizers in Fe3O4 MNPs formation. ? Influence on particle size and morphology is presented. ? Magnetic peculiarities are discussed. - Abstract: Stable magnetic magnetite nanoparticles (Fe3O4 NPs) were synthesized using the chemical co-precipitation method of ferrous (Fe2+)/ferric (Fe3+) mixed aqueous salt solutions in presence of well-defined biocompatible low generation (poly)amidoamine (PAMAM)-based dendrimers with end-grafted n ethylene glycol ether (n = 1, 2, 9) moieties, accessible by means of straightforward consecutive divergent synthesis methodologies including addition and amidation cycles. Addition of NH4OH to the respective dendritic nanoreagent containing iron salt solution produced dendritic stabilized uniform shaped magnetite nanoparticles. The structural and magnetic properties of Fe3O4 NPs were analyzed by FT-IR spectroscopy, thermogravimetry (TG), X-ray powder diffraction (XRPD), transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) vibrating sample magnetometry (VSM). The coherence of affecting the average magnetite particle diameter in range of 5.6 (±1.4)–10.1 (±1.9) nm by the dendritic scaffold, the number and length of the attached ethylene glycol ether termini, as well as the adjusted stabilizer-to-Fe3O4 ratio is discussed along with their magnetic peculiarities.

2012-02-15

92

Polyaniline-coated Fe3O4 nanoparticles: An anion exchange magnetic sorbent for solid-phase extraction.  

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In this study, the capability of the prepared polyaniline-coated Fe(3) O(4) nanoparticles for magnetic solid-phase extraction of three parabens from environmental wastewater, cream, and toothpaste samples is presented. Synthesized Fe(3) O(4) nanoparticles were coated with sulfate-doped polyaniline via polymerization of aniline in the presence of Fe(3) O(4) nanoparticles and sulfuric acid. Here, polyaniline-coated Fe(3) O(4) nanoparticles are presented as anion exchange sorbent, which extract anionic form of parabens via anion exchange with dopant of polyaniline. The experimental conditions affecting extraction efficiency were further studied and optimized. The experimental results showed that maximum extraction efficiency can be obtained at 70 mL sample solution of pH 8, extraction and desorption times of 2 and 1 min, respectively, 100 ?L of 3% (v/v) acetic acid in acetonitrile as eluent, and 100 mg of the adsorbent. Under these conditions, the linear dynamic ranges were 0.5-100 ?g/L with good correlation coefficients (0.998-0.999). The detection limits were in the range of 0.3-0.4 ?g/L and the relative standard deviations were less than 2.4 (n = 5) for the three parabens. Finally, this fast and efficient method was further employed for determination of target analytes in cream, toothpaste, and environmental wastewater samples and satisfactory results were obtained. PMID:22833522

Tahmasebi, Elham; Yamini, Yadollah; Mehdinia, Ali; Rouhi, Fateme

2012-09-01

93

Particle speciation during PEG–Fe3O4 hybrid nanoparticle self-assembly on Si(Ti)O2  

International Nuclear Information System (INIS)

The kinetics of assembly of polyethylene glycol (PEG)-coated superparamagnetic Fe3O4 nanoparticles in aqueous suspension on planar Si(Ti)O2 surfaces have been determined using high-resolution optical waveguide lightmode spectroscopy (OWLS). Analysis of the results revealed that the initially uniform population was spontaneously transformed into two types of particles with significantly different adsorption behaviour.

2011-01-01

94

The changes of T lymphocytes and cytokines in ICR mice fed with Fe3O4 magnetic nanoparticles  

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Full Text Available Jun Wang1, Baoan Chen1, Nan Jin1, Guohua Xia2, Yue Chen1, Ying Zhou1, Xiaohui Cai1,2, Jiahua Ding1, Xiaomao Li3, Xuemei Wang41Department of Hematology, Zhongda Hospital, 2Department of Medical Laboratory, Medical School, Southeast University, Nanjing, People's Republic of China; 3Department of Physics, University of Saarland, Saarbruecken, Germany; 4National Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of ChinaAbstract: The aim of this article is to study the changes inhibited T lymphocytes and cytokines related to the cellular immunity in ICR (imprinting control region mice fed with Fe3O4 magnetic nanoparticles (Fe3O4-MNPs. The Fe3O4-MNPs were synthesized, and their characteristics such as particle size, zeta potential, and X-ray diffraction patterns were measured and determined. All ICR mice were sacrificed after being exposed to 0, 300, 600, and 1200 mg/kg of Fe3O4-MNPs by single gastric administration for 14 days. Splenocytes proliferation was indicated with stimulate index by MTT assay; release of cytokines in the serum of ICR mice was detected by enzyme-linked immunosorbent assay, and the phenotypic analyses of T-lymphocyte subsets were performed using flow cytometry. Our results indicated that there were no significant differences in splenocyte proliferation and release of cytokines between exposed and control groups. Furthermore, there was no significant difference in the proportions of T-lymphocyte subsets in the low-dose Fe3O4-MNPs group when compared to the control group, but the proportions of CD3+CD4+ and CD3+CD8+ T-lymphocyte subsets both in the medium- and high-dose Fe3O4-MNPs groups were higher than those in the control group. It is concluded that a high dose of Fe3O4-MNPs, to some extent, could influence in vivo immune function of normal ICR mice.Keywords: Fe3O4, magnetic nanoparticles, splenocyte proliferation, release of cytokines, T-lymphocyte subsets, ICR mice

Wang J

2011-04-01

95

Novel magnetic Fe3O4-C nanoparticles as adsorbents for removal of organic dyes from aqueous solution  

International Nuclear Information System (INIS)

Highlights: ? In this work, novel magnetic Fe3O4-C nanoparticles have been synthesized and employed as high efficient adsorbent for removal cationic dyes from polluted water. ? While up to now, little study is done on adsorption of dyes by the Fe3O4-C nanoparticles. ? Hence, here we provide a simply and environment friendly method for removal of cationic dyes or other pollutants from water. - Abstract: The magnetic Fe3O4/C core-shell nanoparticles have been synthesized by a simple strategy and used as adsorbents for removal of organic dyes from aqueous solution. The resulting products are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectra and Fourier transform infrared spectra (FTIR). Adsorption performances of the nanomaterial adsorbents are tested with removal of methylene blue (MB) and cresol red (CR) from aqueous solution. The effects of solution pH value, adsorption time and capacity of the nanocomposites have been fully investigated. The results reveal that the nanospheres can be easily manipulated by an external magnetic field with high separation efficiency. In addition, the process is clean and safe for purifying water pollution. The prepared Fe3O4/C complex nanomaterials could thus be used as promising adsorbents for the remove organic dyes, especially, cationic dye, from polluted water.

2011-10-15

96

Use of Fe3O4 Nanoparticles for Enhancement of Biosensor Response to the Herbicide 2,4-Dichlorophenoxyacetic Acid  

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Full Text Available Magnetic nanoparticles of Fe3O4 were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe3O4 nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP and Fe3O4 nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P. The incorporation of the Fe3O4 nanoparticles together with ALP into a sol gel/chitosan biosensor membrane has led to the enhancement of the biosensor response, with an improved linear response range to the substrate AA2P (5-120 μM and increased sensitivity. Using the inhibition property of the ALP, the biosensor was applied to the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D. The use of Fe3O4 nanoparticles gives a two-fold improvement in the sensitivity towards 2,4-D, with a linear response range of 0.5-30 μgL-1. Exposure of the biosensor to other toxicants such as heavy metals demonstrated only slight interference from metals such as Hg2+, Cu2+, Ag2+ and Pb2+. The biosensor was shown to be useful for the determination of the herbicide 2, 4-D because good recovery of 95-100 percent was obtained, even though the analysis was performed in water samples with a complex matrix. Furthermore, the results from the analysis of 2,4-D in water samples using the biosensor correlated well with a HPLC method.

Ishak Zamri

2008-09-01

97

XPS analysis of oleylamine/oleic acid capped Fe3O4 nanoparticles as a function of temperature  

Science.gov (United States)

Fe3O4 nanoparticles were synthesized solvothermally using oleylamine and oleic acid as surfactants, and the surface composition was determined by X-ray photoelectron spectroscopy (XPS) as a function of temperature, from the as-synthesized nanoparticles to those annealed under vacuum at 883K. XPS of the as-synthesized nanoparticles was consistent with a surface composition of stoichiometric Fe3O4 capped with a mixture of monodentate carboxylate and chemisorbed amine, although the surface was enriched in carboxylate over that present in the synthesis reaction concentration. The method of synthesis and capping surfactants effectively protect the nanoparticle surface from detectable hydroxylation. The capped nanoparticle is stable for 24 h at 373K, and the capping agents persist to 523K, at which point the oleylamine decomposes to desorb nitrogen and deposit aliphatic carbon from the capping tail. The carboxylate decomposes over a wider range and at 883K some carboxylate remains on the surface. The iron oxide nanoparticle undergoes substantial reduction as the aliphatic capping tail decomposes. While the as-introduced nanoparticle is essentially Fe3O4, reduction to FeO, Fe and Fe3C occurs sequentially as the nanoparticle is heated to higher temperatures.

Wilson, D.; Langell, M. A.

2014-06-01

98

Electrostatic Self-Assembly of Fe3O4 Nanoparticles on Graphene Oxides for High Capacity Lithium-Ion Battery Anodes  

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Full Text Available Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g?1, high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyltrimethoxysilane (APTMS] in an acidic solution (pH = 2 followed by in situ chemical reduction. Thus prepared Fe3O4/GS composite showed an excellent rate capability as well as much enhanced cycling stability compared with Fe3O4 electrode. The superior electrochemical responses of Fe3O4/GS composite disks assure the advantages of: (1 electrostatic self-assembly between high storage-capacity materials with GO; and (2 incorporation of GS in the Fe3O4/GS composite for high capacity lithium-ion battery application.

Jung Kyoo Lee

2013-09-01

99

Electrostatic Self-Assembly of Fe3O4 Nanoparticles on Graphene Oxides for High Capacity Lithium-Ion Battery Anodes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g?1), high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS) were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-asse...

Taegyune Yoon; Jaegyeong Kim; Jinku Kim; Jung Kyoo Lee

2013-01-01

100

Magnetic Fe3O4 nanoparticles and chemotherapy agents interact synergistically to induce apoptosis in lymphoma cells  

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Full Text Available Hongmei Jing1, Jing Wang1, Ping Yang1, Xiaoyan Ke1, Guohua Xia2, Baoan Chen21Department of Hematology and Lymphoma Research Center, Peking University Third Hospital, Beijing, People’s Republic of China; 2Department of Hematology, The Affiliated Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of ChinaAbstract: The purpose of this study was to investigate the potential effects of combination therapy using magnetic nanoparticles of Fe3O4 (MNP-Fe3O4 and chemotherapeutic drugs on lymphoma cells. Proliferation, inhibition, and viability of Raji cells were detected by MTT and trypan blue exclusion. The percentage of cells undergoing apoptosis was detected by flow cytometry using fluorescein isothiocyanate-annexin V and propidium iodide staining. p53 and nuclear factor-?B (NF-?B protein levels were measured by Western blot. The results showed that proliferation of Raji cells was inhibited by adriamycin or daunorubicin in a dose-and time-dependent manner. Cell sensitivity was improved and the 50% inhibitory concentrations of adriamycin and daunorubicin decreased when combined with a MNP-Fe3O4 carrier. Interestingly, increased apoptosis in Raji lymphoma cells was accompanied by upregulation of p53 protein and downregulation of NF-?B protein. Furthermore, the combination of MNP-Fe3O4 with adriamycin or daunorubicin increased p53 protein levels and decreased NF-?B protein levels more than adriamycin or daunorubicin alone, indicating that MNP-Fe3O4 could enhance the effect of chemotherapeutic drugs on p53 and NF-?B. Similar results for cell apoptosis and protein expression were not observed for the groups treated with dexamethasone ± MNP-Fe3O4 (P >0.05. These findings suggest a potential clinical application for MNP-Fe3O4 in combination with daunorubicin or adriamycin in the treatment of lymphoma.Keywords: magnetic nanoparticles, Raji cells, apoptosis, p53, NF-?B

Hongmei Jing

2010-11-01

 
 
 
 
101

Bio-inspired green synthesis of Fe3O4 spherical magnetic nanoparticles using Syzygium cumini seed extract  

Science.gov (United States)

A novel and bio-inspired Fe3O4 spherical magnetic nanoparticles (SMNPs) were synthesized using Syzygium cumini (S. cumini) seed extract, which is a non-toxic ecofriendly fruit waste material. S. cumini seed extract acts as a green solvent, reducing and capping agent in which sodium acetate acts as electrostatic stabilizing agent. The green synthesized nanoparticles were characterized with the help of various techniques such as X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), Energy-dispersive spectroscopy (EDS), Vibrating sample magnetometer (VSM), FTIR spectroscopy and nitrogen adsorption and desorption analysis techniques. The XRD study divulged that the synthesized SMNPs have inverse spinel cubic structure. The hysteresis loop of Fe3O4 nanoparticles shows an excellent ferromagnetic behavior with saturation magnetization value of 13.6 emu/g.

Venkateswarlu, Sada; Natesh Kumar, B.; Prasad, C. H.; Venkateswarlu, P.; Jyothi, N. V. V.

2014-09-01

102

The reversal effect of magnetic Fe3O4 nanoparticles loaded with cisplatin on SKOV3/DDP ovarian carcinoma cells  

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Full Text Available Zhi Jiang1,6, Bao-An Chen1,6, Guo-Hua Xia1, Qiang Wu2, Yu Zhang1, Tie-Yan Hong1, Wei Zhang1, Jian Cheng1, Feng Gao1, Li-Jie Liu3, Xiao-Mao Li4, Xue-Mei Wang51Department of Hematology, the Affiliated Zhongda Hospital of Southeast University, Nanjing, China; 2The Jiangsu Province Cancer Hospital, Nanjing, China; 3Institutions of Physiology, Southeast University, Nanjing, China; 4Department of Physics, University of Saarland, Saarbruechen, Germany; 5National Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, China; 6These authors have contributed equally to this workAbstract: To explore whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4 loaded with cisplatin can reverse the diaminedichloro platinum (DDP resistance to multidrug resistance of ovarian carcinoma cells and to investigate its mechanisms. The SKOV3/DDP cells were divided into DDP treatment (DDP group, MNPs-Fe3O4 treatment (MNPs-Fe3O4 group, DDP + MNPs-Fe3O4 treatment (DDP + MNPs-Fe3O4 group, and control group. After incubation with those conjugates for 48 h, the cytotoxic effects were measured by MTT assay. Apoptosis and the intracellular DDP concentration were investigated by flow cytometry and inductively coupled plasma atomic emission spectroscopy, respectively. The expression of apoptosis associated gene Bcl-2 mRNA was detected by reverse transcription polymerase chain reaction and the expressions of MDR1, lung resistance-related protein (LRP, and P-glycoprotein (P-gp genes were studied by Western blot. Our results indicated that the 50% inhibition concentration (IC50 of the MNPs-Fe3O4 loaded with DDP was 17.4 µmol/ l, while the IC50 was 39.31 µmol/l in DDP groups (p < 0.05; Apoptosis rates of SKOV3/DDP cells increased more than those of DDP groups. Accumulation of intracellular cisplatin in DDP + MNPs-Fe3O4 groups was higher than those in DDP groups (p < 0.05. Moreover, the expression of Bcl-2 mRNA and the protein expressions of MDR1, LRP, and P-gp were decreased when compared with those of DDP groups, respectively. Our results suggest that MNPs-Fe3O4 can reverse the DDP resistance to the ovarian carcinoma cell. The effects may be associated with over-expression of MDR1, LRP, P-gp, and Bcl-2, which can increase the intracellular platinum accumulation and induce the cell apoptosis.Keywords: magnetic nanoparticles of Fe3O4 , multidrug resistance reversal, SKOV3/DDP, MDR1, LRP, P-gp, Bcl-2

Zhi Jiang

2009-04-01

103

Aqueous nickel-nitrilotriacetate modified Fe3O4 NH3+ nanoparticles for protein purification and cell targeting  

Science.gov (United States)

A comprehensive totally aqueous phase synthesis of nickel-nitrilotriacetate (Ni-NTA) modified superparamagnetic Fe3O4 nanoparticles is presented. The Fe3O4-NTA-Ni nanoparticles are able to perform efficient and specific purification of 6-His tagged proteins from crude cell lysates, as evidenced by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. The average binding capacity, as demonstrated by streptopain (MW 42 kDa), is 0.23 mg/mg (protein/Fe3O4-NTA-Ni). Considering the high affinity and specificity of the binding between hexahistidine motif and Ni-NTA, Ni-NTA modified nanoparticles could act as a module to carry 6-His tagged proteins on the particle surface with molecular orientation control, since only the 6-His domain could be attached. These modularly designed functional nanoparticles enhance cancer cell targeting, as supported by the in vitro receptor mediated targeting assay using RGD-4C-6-His fusion peptide. The nanoparticles show no significant hemolysis for human blood and could be investigated further for their in vivo functional imaging applications.

Shieh, Dar-Bin; Su, Chia-Hao; Chang, Fong-Yu; Wu, Ya-Na; Su, Wu-Chou; Hwu, Jih Ru; Chen, Jyh-Horng; Yeh, Chen-Sheng

2006-08-01

104

Magnetic nanoparticle (Fe3O4) impregnated onto tea waste for the removal of nickel(II) from aqueous solution  

International Nuclear Information System (INIS)

The removal of Ni(II) from aqueous solution by magnetic nanoparticles prepared and impregnated onto tea waste (Fe3O4-TW) from agriculture biomass was investigated. Magnetic nanoparticles (Fe3O4) were prepared by chemical precipitation of a Fe2+ and Fe3+ salts from aqueous solution by ammonia solution. These magnetic nanoparticles of the adsorbent Fe3O4 were characterized by surface area (BET), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infrared Spectroscopy (FT-IR). The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The kinetics followed is first order in nature, and the value of rate constant was found to be 1.90 x 10-2 min-1 at 100 mg L-1 and 303 K. Removal efficiency decreases from 99 to 87% by increasing the concentration of Ni(II) in solution from 50 to 100 mg L-1. It was found that the adsorption of Ni(II) increases by increasing temperature from 303 to 323 K and the process is endothermic in nature. The adsorption isotherm data were fitted to Langmuir and Freundlich equation, and the Langmuir adsorption capacity, Qo, was found to be (38.3) mg g-1. The results also revealed that nanoparticle impregnated onto tea waste from agriculture biomass, can be an attractive option for metal removal from industrial effluent.

2011-02-15

105

Fe3O4@SiO2 core-shell nanoparticles: Synthesis, characterization and application in environmental remediation  

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In this study, Fe3O4@SiO2 core-shell structure was synthesized by a one pot co-precipitation method, and its applicability as Low-Cost Abundantly available adsorbent for removal of heavy metal ions from simulated industrial waste water was examined. The detailed characterization of morphology showed that the Fe3O4 nanoparticle was coated with amorphous silica of a shell thickness of 2-3 nm. The core-shell magnetic nanoparticles (MNPs) showed a great removal capability of four different heavy metal ions (Zn (II), Co (II), Ni (II), and Cu (II). These MNPs showed high magnetic saturation values, which ensure the convenience of recovering sorbent for reusability with the assistance of external magnetic field. Specifically, this present study shows the use of MNPs as an effective recyclable adsorbent for environmental remediation.

Majeed, J.; Ramkumar, Jayshree; Chandramouleeswaran, S.; Tyagi, A. K.

2014-04-01

106

Intraperitoneal injection of magnetic Fe3O4-nanoparticle induces hepatic and renal tissue injury via oxidative stress in mice  

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Full Text Available Ping Ma,1,2,* Qing Luo,2,* Jiaoe Chen,1 Yaping Gan,1 Juan Du,2 Shumao Ding,2 Zhuge Xi,3 Xu Yang2 1College of Basic Medical Sciences, Hubei University of Science and Technology, Xianning, People's Republic of China; 2Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, People's Republic of China; 3Tianjin Institute of Health and Environmental Medicine, Tianjin, People's Republic of China*These authors contributed equally to this workAbstract: Because of its unique magnetic properties, the iron oxide (Fe3O4 nanoparticle has been widely exploited and its application in various fields has promised immense benefits. However, doubts exist over the use of Fe3O4-nanoparticles in human beings. Thus, the aim of the current study was to find out the potential safety range of medical use. Twenty-five Kunming mice were exposed to Fe3O4-nanoparticles via intraperitoneal injection daily for 1 week at doses of 0, 5, 10, 20, and 40 mg/kg. Hepatic and renal tissues were sliced for physiological observation. Injuries were observed in the high-dose groups (20 and 40 mg/kg compared with the control group (0 mg/kg. Biomarkers of reactive oxygen species, glutathione, malondialdehyde, DNA-protein crosslinks, and 8-hydroxy-2'-deoxyguanosine in the hepatic and renal tissues were detected. Injury to tissues and oxidative damage to cells at the molecular level was found. The safest dose recommended from the results of this study is 5 mg/kg, as we believe this to be an upper limit balancing the benefits and risks for sub-long-term exposure.Keywords: Fe3O4-nanoparticles, reactive oxygen species, glutathione, malondialdehyde, DNA-protein crosslinks, 8-hydroxy-2'-deoxyguanosine

Ma P

2012-09-01

107

One-Pot Green Synthesis and Bioapplication ofl-Arginine-Capped Superparamagnetic Fe3O4 Nanoparticles  

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Full Text Available Abstract Water-solublel-arginine-capped Fe3O4 nanoparticles were synthesized using a one-pot and green method. Nontoxic, renewable and inexpensive reagents including FeCl3,l-arginine, glycerol and water were chosen as raw materials. Fe3O4 nanoparticles show different dispersive states in acidic and alkaline solutions for the two distinct forms of surface bindingl-arginine. Powder X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the structure of Fe3O4 nanocrystals. The products behave like superparamagnetism at room temperature with saturation magnetization of 49.9 emu g?1 and negligible remanence or coercivity. In the presence of 1-ethyl-3-(dimethylaminopropyl carbodiimide hydrochloride, the anti-chloramphenicol monoclonal antibodies were connected to thel-arginine-capped magnetite nanoparticles. The as-prepared conjugates could be used in immunomagnetic assay. (See supplementary material 1 Electronic supplementary material The online version of this article (doi:10.1007/s11671-009-9480-x contains supplementary material, which is available to authorized users. Click here for file

Lai Yongchao

2009-01-01

108

Biocompatibility of Fe3O4 nanoparticles evaluated by in vitro cytotoxicity assays using normal, glia and breast cancer cells  

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In order to reveal the biocompatibility of Fe3O4 nanoparticles and bipolar surfactant tetramethylammonium 11-aminoundecanoate cytotoxicity tests were performed as a function of concentration from low (0.1 µg ml-1) to higher concentration (100 µg ml-1) using various human glia, human breast cancer and normal cell lines. Cytotoxicity tests for human glia (D54MG, G9T, SF126, U87, U251, U373), human breast cancer (MB157, SKBR3, T47D) and normal (H184B5F5/M10, WI-38, SVGp12) cell lines exhibited almost nontoxicity and reveal biocompatibility of Fe3O4 nanoparticles in the concentration range of 0.1-10 µg ml-1, while accountable cytotoxicity can be seen at 100 µg ml-1. The results of our studies suggest that Fe3O4 nanoparticles coated with bipolar surfactant tetramethylammonium 11-aminoundecanoate are biocompatible and promising for bio-applications such as drug delivery, magnetic resonance imaging and magnetic hyperthermia.

Ankamwar, B.; Lai, T. C.; Huang, J. H.; Liu, R. S.; Hsiao, M.; Chen, C. H.; Hwu, Y. K.

2010-02-01

109

Biocompatibility of Fe(3)O(4) nanoparticles evaluated by in vitro cytotoxicity assays using normal, glia and breast cancer cells.  

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In order to reveal the biocompatibility of Fe(3)O(4) nanoparticles and bipolar surfactant tetramethylammonium 11-aminoundecanoate cytotoxicity tests were performed as a function of concentration from low (0.1 microg ml(-1)) to higher concentration (100 microg ml(-1)) using various human glia, human breast cancer and normal cell lines. Cytotoxicity tests for human glia (D54MG, G9T, SF126, U87, U251, U373), human breast cancer (MB157, SKBR3, T47D) and normal (H184B5F5/M10, WI-38, SVGp12) cell lines exhibited almost nontoxicity and reveal biocompatibility of Fe(3)O(4) nanoparticles in the concentration range of 0.1-10 microg ml(-1), while accountable cytotoxicity can be seen at 100 microg ml(-1). The results of our studies suggest that Fe(3)O(4) nanoparticles coated with bipolar surfactant tetramethylammonium 11-aminoundecanoate are biocompatible and promising for bio-applications such as drug delivery, magnetic resonance imaging and magnetic hyperthermia. PMID:20090199

Ankamwar, B; Lai, T C; Huang, J H; Liu, R S; Hsiao, M; Chen, C H; Hwu, Y K

2010-02-19

110

Biocompatibility of Fe3O4 nanoparticles evaluated by in vitro cytotoxicity assays using normal, glia and breast cancer cells  

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In order to reveal the biocompatibility of Fe3O4 nanoparticles and bipolar surfactant tetramethylammonium 11-aminoundecanoate cytotoxicity tests were performed as a function of concentration from low (0.1 ?g ml-1) to higher concentration (100 ?g ml-1) using various human glia, human breast cancer and normal cell lines. Cytotoxicity tests for human glia (D54MG, G9T, SF126, U87, U251, U373), human breast cancer (MB157, SKBR3, T47D) and normal (H184B5F5/M10, WI-38, SVGp12) cell lines exhibited almost nontoxicity and reveal biocompatibility of Fe3O4 nanoparticles in the concentration range of 0.1-10 ?g ml-1, while accountable cytotoxicity can be seen at 100 ?g ml-1. The results of our studies suggest that Fe3O4 nanoparticles coated with bipolar surfactant tetramethylammonium 11-aminoundecanoate are biocompatible and promising for bio-applications such as drug delivery, magnetic resonance imaging and magnetic hyperthermia.

2010-02-19

111

Activated carbon/Fe(3)O(4) nanoparticle composite: fabrication, methyl orange removal and regeneration by hydrogen peroxide.  

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In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe(3)O(4) nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe(3)O(4) nanoparticles, were fabricated by a modified impregnation method using HNO(3) as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO(3) (powdered activated carbon modified by HNO(3)) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe(3)O(4) nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide. PMID:21840037

Do, Manh Huy; Phan, Ngoc Hoa; Nguyen, Thi Dung; Pham, Thi Thu Suong; Nguyen, Van Khoa; Vu, Thi Thuy Trang; Nguyen, Thi Kim Phuong

2011-11-01

112

Electrochemical detection of short HIV sequences on chitosan/Fe3O4 nanoparticle based screen printed electrodes  

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In this study, a novel CS/Fe3O4 nanobiocomposite-based platform for electrochemical detection of HIV-1 was developed. The most attractive feature of this system is a suitable microenvironment (Fe3O4 nanoparticles) which could contribute to electron transfer and thus sensitivity enhancement when using methylene blue (MB) as an external mediator and Square Wave Voltammetry (SWV), Electrochemical Impedance Spectroscopy (EIS) techniques. The proposed screen printed electrode (SPE) had a low detection limit (as low as 50 pM), acceptable stability and good reproducibility, which would be valuable for clinical diagnosis. In addition, this sensing interface may be feasibly adapted for multiplexed detection of other species of bacterial pathogens.

2011-03-12

113

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.  

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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

2012-10-01

114

Modified properties of Fe3O4 nanoparticles on incorporation of optically active ZnSe  

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A facile two-steps method for preparation of the Fe3O4/ZnSe nanocomposite at room temperature has been reported. The prepared samples were characterized by XRD, SQUID VSM, Mössbauer, UV-vis and Photoluminescence (PL) spectroscopy. Zero-field-cooled (ZFC) and field-cooled (FC) measurements show irreversibility up to room temperature and a superparamagnetic blocked state below 250 K. Mössbauer spectra at RT shows typical relaxed sextet pattern with a superparamagnetic doublet. PL spectra show strong near band edge emission and some weak peaks related to different defects levels.

Roychowdhury, A.; Das, A.; Pati, S. P.; Kumar, S.; Das, D.

2014-04-01

115

The Effect of Emulation Formulation to Encapsulation of Fe3O4 Magnetic nanoparticle with Poly (Lactic Acid)  

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The research to study the effect of emulsion formulation to encapsulation Fe3O4 magnetic nanoparticle with Poly(Lactic Acid) (PLA) has been done. Microemulsion by ultrasonic probe is used in encapsulation process and continued by solvent evaporation. Emulsion formulation has been varied by changing oil phase volume in the oil in water (o/w) emulsion system from 6 mL, 8 mL, 10 mL, 12 mL and 14 mL, whereas water phase volume is constant (55 mL). Sample characterization is carried on by Scanning Electron Microscope (SEM) to know the morphology and sample size. X-Ray Diffractometer (XRD) is used to identify the phase, Vibrating Sample Magnetometer (VSM) is used to measure magnetic saturation while Neutron Activation Analysis (NAA) is used to measure encapsulation percentage of Fe3O4 with PLA. The smallest nanosphere is resulted by emulsion formulation (o/w) of 14/55 with the main sample size 382 nm. The maximum magnetic saturation of Fe3O4 + PLA nanosphere is 2.556 emu/g and encapsulation percentage is 24.94 %. (author)

2008-12-01

116

Magnetic and optical properties of Ag@SiO2-FITC-Fe3O4 hybrid nanoparticles  

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Highlights: • New magnetic/fluorescent nanoparticles were synthesized. • The silver core led to a maximum 4-fold enhanced fluorescence of fluorophore. • Maximum enhancement factor was obtained when metal-fluorophore distance is 5 nm. • Magnetism and fluorescence appeared simultaneously for nanoparticles in solution. -- Abstract: Nanoparticles composed of a silver core coated with a silica shell (Ag@SiO2) were prepared. A dye, fluorescein isothiocyanate (FITC), was further encapsulated during the growth of a second silica shell onto Ag@SiO2 nanoparticles. The proximity of silver nanoparticles led to a 4-fold maximal enhancement in the fluorescence of FITC when the first silica shell thickness was set at 5 nm. After amino-functionalization of Ag@SiO2-FITC nanoparticles, iron oxide nanoparticles were bonded to their surface. The magnetic and metal-enhanced fluorescence properties appeared simultaneously when Ag@SiO2-FITC-Fe3O4 hybrid nanoparticles were dispersed in a solution

2014-03-01

117

Fe3O4 nanoparticles with daunorubicin induce apoptosis through Caspase-8/PARP pathway and inhibit K562 leukemia cell-induced tumor growth in vivo  

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Nanomaterials can enhance the delivery and treatment efficiency of anti-cancer drugs, but the mechanisms of the tumor-reducing activity of Fe3O4 nanoparticles with daunorubicin have not been established. Here we investigate the synergistic effects of Fe3O4 nanoparticles with daunorubicin on the induction of apoptosis using K562 leukemia cells. Fe3O4 nanoparticles increased the ability of daunorubicin to induce apoptosis in both adriamycin-sensitive and adriamycin-resistant K562 cells through ...

Zhang, Gen; Lai, Bin Bin; Zhou, Yan Yan; Chen, Bao An; Wang, Xue Mei; Lu, Qun; Chen, Yan-hua

2011-01-01

118

Preparation and characterization of Fe3O4 magnetic nano-particles modified with poly (N-isopropylacrylamide) by UV irradiation  

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Fe3O4 magnetic nanoparticles were modified with poly (N-isopropylacrylamide) under UV irradiation. It has been found that the diameter with narrow distribution of the modified Fe3O4 nanoparticles measured by PCS in aqueous solution can be controlled easily by changing concentration of monomer NIPAM and cross-linker MBA, temperature and time. It has been also shown that the modified Fe3O4 nanoparticles are featured by lower critical solution temperature (LCST) while the temperature varies from 25 degree C to 39 degree C. This may suggest promising application of the nanopartucles in medicine. (authors)

2004-10-01

119

Removal of heavy metals from aqueous solutions using Fe3O4, ZnO, and CuO nanoparticles  

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This study investigated the removal of Cd2+, Cu2+, Ni2+, and Pb2+ from aqueous solutions with novel nanoparticle sorbents (Fe3O4, ZnO, and CuO) using a range of experimental approaches, including, pH, competing ions, sorbent masses, contact time, scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The images showed that Fe3O4, ZnO, and CuO particles had mean diameters of about 50 nm (spheroid), 25 nm (rod shape), and 75 nm (spheroid), respectively. Tests were performed under batch conditions to determine the adsorption rate and uptake at equilibrium from single and multiple component solutions. The maximum uptake values (sum of four metals) in multiple component solutions were 360.6, 114.5, and 73.0 mg g?1, for ZnO, CuO, and Fe3O4, respectively. Based on the average metal removal by the three nanoparticles, the following order was determined for single component solutions: Cd2+ > Pb2+ > Cu2+ > Ni2+, while the following order was determined in multiple component solutions: Pb2+ > Cu2+ > Cd2+ > Ni2+. Sorption equilibrium isotherms could be described using the Freundlich model in some cases, whereas other isotherms did not follow this model. Furthermore, a pseudo-second order kinetic model was found to correctly describe the experimental data for all nanoparticles. Scanning electron microscopy, energy dispersive X-ray before and after metal sorption, and soil solution saturation indices showed that the main mechanism of sorption for Cd2+ and Pb2+ was adsorption, whereas both Cu2+ and Ni2+ sorption were due to adsorption and precipitation. These nanoparticles have potential for use as efficient sorbents for the removal of heavy metals from aqueous solutions and ZnO nanoparticles were identified as the most promising sorbent due to their high metal uptake.

2012-08-01

120

One-pot reaction for the large-scale synthesis of hyperbranched polyglycerol-grafted Fe3O4 nanoparticles.  

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Fe3O4 nanoparticles with surface hydroxyl groups (MNP-OH), prepared by the thermal decomposition of ferric oxalate pentahydrate in triethylene glycol, were grafted in situ with polyglycerol through the ring-opening polymerization of glycidol. By this method, hyperbranched polyglycerol-grafted Fe3O4 nanoparticles (HPG-grafted MNPs) can be obtained on an ultra-large scale of 50 g in a single reaction under laboratory conditions, and it is anticipated that the production of the HPG-grafted MNPs could be scaled up with the use of larger reaction vessels. The successful grafting of HPG onto the nanoparticles was confirmed by (1)H NMR and XPS analyses. The as-synthesized nanoparticles can be tuned from 8 to 24 nm in diameter by varying the reaction conditions. The size, morphology, and surface component of the nanoparticles were characterized by TEM, XPS, and XRD. The HPG-grafted MNPs are highly dispersible in aqueous media such as cell culture medium and serum. Since these magnetic nanoparticles possess desirable magnetic properties, controllable size, and can be produced by a facile inexpensive method, they can be potentially applied as a novel contrast agent for enhancing a MRI signal. PMID:23904070

Wang, Liang; Su, Dan; Zeng, Lintao; Liu, Ning; Jiang, Lai; Feng, Xuequan; Neoh, K G; Kang, E T

2013-10-01

 
 
 
 
121

Monodisperse magnetizable silica composite particles from heteroaggregate of carboxylic polystyrene latex and Fe3O4 nanoparticles  

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Monodisperse magnetizable silica composite particles were prepared from heteroaggregates of carboxylic polystyrene latex and Fe3O4 nanoparticles. It was found that the heteroaggregation of the carboxylic latex and Fe3O4 nanoparticles is dependent on the pH of the solution. At low pH value (pH 2-4), the aggregation proceeds effectively due to opposite charges on the surfaces of the latex and the magnetic nanoparticles. At high pH value (pH>8), no aggregation was observed due to the negative charge on both the surface of the latex and the magnetic nanoparticles. The heteroaggregate of the latex and magnetic nanoparticles was found to be stable in a wide range of pH values, due to the existence of coordination interactions at the interface of the latex and magnetic nanoparticles. After silica layer coating on the heteroaggregate by the Stoeber process and removal of the latex by calcination, hollow monodisperse magnetizable silica composite particles are obtained

2008-02-06

122

FMR study of carbon nanotubes filled with Fe3O4 nanoparticles  

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Ordered arrays of carbon nanotubes were produced using a non-catalytic chemical vapour deposition. The multiwall nanotubes with an inner diameter of 120 nm were grown inside porous alumina templates and then filled with a magnetic colloid of 7.5 nm Fe3O4 particles. X-ray diffraction, electron microscopy and ferromagnetic resonance (FMR) were used to characterize structural and magnetic properties of the grown samples. To estimate the filling factor from the angular dependence of the FMR resonance field, we have derived an effective demagnetization factor for our system using the formalism proposed by Skomsky and Dubowik. Angular dependence of the FMR line width allows one to conclude about the non-uniform filling, while temperature dependent measurements reflect typical features of a superparamagnetic resonance.

Kopyl, S.; Timopheev, A. A.; Bystrov, V. S.; Bdikin, I.; Teixeira, B. M. S.; Maevskij, E.; Sobolev, N. A.; Sousa, A. C. M.

2014-05-01

123

Molecular imprinting and immobilization of cellulase onto magnetic Fe3O4@SiO2 nanoparticles.  

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Supermagnetic Fe3O4@SiO2 nanoparticles were molecular-imprinted prepared with cellulase as the template. The molecular imprinted nanoparticles were used as support to immobilization of cellulase. The transmission electron microscopy confirmed the core-shell structure and revealed that the size of the nanoparticles was around 10 nm. It was observed that cellulase was immobilized on the nanoparticles successfully from the Fourier transform infrared spectra. The adsorption of cellulase on the nanoparticles was specific and rapid. A high immobilization efficiency of 95% was achieved after the optimization. At 70 degrees C, the half-life of the immobilized cellulase was 3.3-fold of the free enzyme. Compared with the free enzyme, the immobilized cellulase has the same optimal pH, higher optimal temperature, better thermal stability and higher catalytic efficiency. The results strongly suggest that the immobilized cellulase on molecular imprinted Fe3O4@SiO2 has the potential applications in the production of bioethanol, paper and pulp industry, and pharmaceutical industry. PMID:24734713

Li, Yue; Wang, Xiang-Yu; Zhang, Rui-Zhuo; Zhang, Xiao-Yun; Liu, Wei; Xu, Xi-Ming; Zhang, Ye-Wang

2014-04-01

124

Green Biosynthesis and Characterization of Magnetic Iron Oxide (Fe3O4 Nanoparticles Using Seaweed (Sargassum muticum Aqueous Extract  

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Full Text Available The synthesis of nanoparticles has become a matter of great interest in recent times due to their various advantageous properties and applications in a variety of fields. The exploitation of different plant materials for the biosynthesis of nanoparticles is considered a green technology because it does not involve any harmful chemicals. In this study, iron oxide nanoparticles (Fe3O4-NPs were synthesized using a rapid, single step and completely green biosynthetic method by reduction of ferric chloride solution with brown seaweed (BS, Sargassum muticum water extract containing sulphated polysaccharides as a main factor which acts as reducing agent and efficient stabilizer. The structural and properties of the Fe3O4-NPs were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FESEM, energy dispersive X-ray fluorescence spectrometry (EDXRF, vibrating sample magnetometry (VSM and transmission electron microscopy. The average particle diameter as determined by TEM was found to be 18 ± 4 nm. X-ray diffraction showed that the nanoparticles are crystalline in nature, with a cubic shape. The nanoparticles synthesized through this biosynthesis method can potentially useful in various applications.

Rosfarizan Mohamad

2013-05-01

125

Highly selective fluorescent chemosensor for Zn2+ derived from inorganic-organic hybrid magnetic core/shell Fe3O4@SiO2 nanoparticles  

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Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn2+ was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe3O4@SiO2 nanoparticles [NPs] (DTH-Fe3O4@SiO2 NPs) using the silanol hydrolysis approach. The DTH-Fe3O4@SiO2 inorganic-organic hybrid material was characteriz...

Wang, Yujiao; Peng, Xiaohong; Shi, Jinmin; Tang, Xiaoliang; Jiang, Jie; Liu, Weisheng

2012-01-01

126

One-step synthesis of water-dispersible ultra-small Fe3O4 nanoparticles as contrast agents for T1 and T2 magnetic resonance imaging  

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Uniform, highly water-dispersible and ultra-small Fe3O4 nanoparticles were synthesized via a modified one-step coprecipitation approach. The prepared Fe3O4 nanoparticles not only show good magnetic properties, long-term stability in a biological environment, but also exhibit good biocompatibility in cell viability and hemolysis assay. Due to the ultra-small sized and highly water-dispersibility, they exhibit excellent relaxivity properties, the 1.7 nm sized Fe3O4 nanoparticles reveal a low r2/r1 ratio of 2.03 (r1 = 8.20 mM-1 s-1, r2 = 16.67 mM-1 s-1) and the 2.2 nm sized Fe3O4 nanoparticles also appear to have a low r2/r1 ratio of 4.65 (r1 = 6.15 mM-1 s-1, r2 = 28.62 mM-1 s-1). This demonstrates that the proposed ultra-small Fe3O4 nanoparticles have great potential as a new type of T1 magnetic resonance imaging contrast agents. Especially, the 2.2 nm sized Fe3O4 nanoparticles, have a competitive r1 value and r2 value compared to commercial contrasting agents such as Gd-DTPA (r1 = 4.8 mM-1 s -1), and SHU-555C (r2 = 69 mM-1 s-1). In vitro and in vivo imaging experiments, show that the 2.2 nm sized Fe3O4 nanoparticles exhibit great contrast enhancement, long-term circulation, and low toxicity, which enable these ultra-small sized Fe3O4 nanoparticles to be promising as T1 and T2 dual contrast agents in clinical settings.Uniform, highly water-dispersible and ultra-small Fe3O4 nanoparticles were synthesized via a modified one-step coprecipitation approach. The prepared Fe3O4 nanoparticles not only show good magnetic properties, long-term stability in a biological environment, but also exhibit good biocompatibility in cell viability and hemolysis assay. Due to the ultra-small sized and highly water-dispersibility, they exhibit excellent relaxivity properties, the 1.7 nm sized Fe3O4 nanoparticles reveal a low r2/r1 ratio of 2.03 (r1 = 8.20 mM-1 s-1, r2 = 16.67 mM-1 s-1) and the 2.2 nm sized Fe3O4 nanoparticles also appear to have a low r2/r1 ratio of 4.65 (r1 = 6.15 mM-1 s-1, r2 = 28.62 mM-1 s-1). This demonstrates that the proposed ultra-small Fe3O4 nanoparticles have great potential as a new type of T1 magnetic resonance imaging contrast agents. Especially, the 2.2 nm sized Fe3O4 nanoparticles, have a competitive r1 value and r2 value compared to commercial contrasting agents such as Gd-DTPA (r1 = 4.8 mM-1 s -1), and SHU-555C (r2 = 69 mM-1 s-1). In vitro and in vivo imaging experiments, show that the 2.2 nm sized Fe3O4 nanoparticles exhibit great contrast enhancement, long-term circulation, and low toxicity, which enable these ultra-small sized Fe3O4 nanoparticles to be promising as T1 and T2 dual contrast agents in clinical settings. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr05550g

Wang, Guannan; Zhang, Xuanjun; Skallberg, Andreas; Liu, Yaxu; Hu, Zhangjun; Mei, Xifan; Uvdal, Kajsa

2014-02-01

127

Highly selective fluorescent chemosensor for Zn2+ derived from inorganic-organic hybrid magnetic core/shell Fe3O4@SiO2 nanoparticles  

Science.gov (United States)

Magnetic nanoparticles with attractive optical properties have been proposed for applications in such areas as separation and magnetic resonance imaging. In this paper, a simple and novel fluorescent sensor of Zn2+ was designed with 3,5-di-tert-butyl-2-hydroxybenzaldehyde [DTH] covalently grafted onto the surface of magnetic core/shell Fe3O4@SiO2 nanoparticles [NPs] (DTH-Fe3O4@SiO2 NPs) using the silanol hydrolysis approach. The DTH-Fe3O4@SiO2 inorganic-organic hybrid material was characterized by transmission electron microscopy, dynamic light scattering, X-ray power diffraction, diffuse reflectance infrared Fourier transform, UV-visible absorption and emission spectrometry. The compound DTH exhibited fluorescence response towards Zn2+ and Mg2+ ions, but the DTH-Fe3O4@SiO2 NPs only effectively recognized Zn2+ ion by significant fluorescent enhancement in the presence of various ions, which is due to the restriction of the N-C rotation of DTH-Fe3O4@SiO2 NPs and the formation of the rigid plane with conjugation when the DTH-Fe3O4@SiO2 is coordinated with Zn2+. Moreover, this DTH-Fe3O4@SiO2 fluorescent chemosensor also displayed superparamagnetic properties, and thus, it can be recycled by magnetic attraction.

Wang, Yujiao; Peng, Xiaohong; Shi, Jinmin; Tang, Xiaoliang; Jiang, Jie; Liu, Weisheng

2012-01-01

128

Preparation and in vitro evaluation of doxorubicin-loaded Fe3O4 magnetic nanoparticles modified with biocompatible copolymers  

Science.gov (United States)

Background Superparamagnetic iron oxide nanoparticles are attractive materials that have been widely used in medicine for drug delivery, diagnostic imaging, and therapeutic applications. In our study, superparamagnetic iron oxide nanoparticles and the anticancer drug, doxorubicin hydrochloride, were encapsulated into poly (D, L-lactic-co-glycolic acid) poly (ethylene glycol) (PLGA-PEG) nanoparticles for local treatment. The magnetic properties conferred by superparamagnetic iron oxide nanoparticles could help to maintain the nanoparticles in the joint with an external magnet. Methods A series of PLGA:PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide with different molecular weights of polyethylene glycol (PEG2000, PEG3000, and PEG4000) as an initiator. The bulk properties of these copolymers were characterized using 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and differential scanning calorimetry. In addition, the resulting particles were characterized by x-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry. Results The doxorubicin encapsulation amount was reduced for PLGA:PEG2000 and PLGA:PEG3000 triblock copolymers, but increased to a great extent for PLGA:PEG4000 triblock copolymer. This is due to the increased water uptake capacity of the blended triblock copolymer, which encapsulated more doxorubicin molecules into a swollen copolymer matrix. The drug encapsulation efficiency achieved for Fe3O4 magnetic nanoparticles modified with PLGA:PEG2000, PLGA:PEG3000, and PLGA:PEG4000 copolymers was 69.5%, 73%, and 78%, respectively, and the release kinetics were controlled. The in vitro cytotoxicity test showed that the Fe3O4-PLGA:PEG4000 magnetic nanoparticles had no cytotoxicity and were biocompatible. Conclusion There is potential for use of these nanoparticles for biomedical application. Future work includes in vivo investigation of the targeting capability and effectiveness of these nanoparticles in the treatment of lung cancer.

Akbarzadeh, Abolfazl; Mikaeili, Haleh; Zarghami, Nosratollah; Mohammad, Rahmati; Barkhordari, Amin; Davaran, Soodabeh

2012-01-01

129

Ultra-small Fe3O4 nanoparticle decorated graphene nanosheets with superior cyclic performance and rate capability  

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Advanced anode materials for next generation lithium ion batteries have attracted great interest due to the ever increasing demand for powerful, light-weight, and compact electrical devices. In this work, graphene nanosheets decorated with ultra-small Fe3O4 nanoparticles (USIO/G) were synthesized via a facile hydrothermal method. Compared with other reported Fe3O4-based anode composites, USIO/G demonstrated superior cyclic ability and excellent rate capability owing to its ultra-small size of active lithium storage sites, Fe3O4, with an average diameter less than 5 nm. Furthermore, graphene nanosheets played an important role in the overall electrochemical performance of the composite by enhancing the electrical conductivity, forming a flexible network, and providing extra lithium storage sites. The obtained composites were tested for electrochemical performance for a total number of 2120 cycles: a rate capability test with current densities ranged from 90 to 7200 mA g-1 for 920 cycles, followed by a cycling test at 1800 mA g-1 for 1200 cycles. For the rate capability test, steady reversible capacities were delivered under each current density with final reversible capacities of 1177, 1096, 833, 488, 242, and 146 mA h g-1 at 90, 180, 900, 1800, 3600, and 7200 mA g-1, respectively. The subsequent cyclic test demonstrated the superior cyclic stability of USIO/G and a reversible capacity of 437 mA h g-1 at the 2120th cycle was delivered.Advanced anode materials for next generation lithium ion batteries have attracted great interest due to the ever increasing demand for powerful, light-weight, and compact electrical devices. In this work, graphene nanosheets decorated with ultra-small Fe3O4 nanoparticles (USIO/G) were synthesized via a facile hydrothermal method. Compared with other reported Fe3O4-based anode composites, USIO/G demonstrated superior cyclic ability and excellent rate capability owing to its ultra-small size of active lithium storage sites, Fe3O4, with an average diameter less than 5 nm. Furthermore, graphene nanosheets played an important role in the overall electrochemical performance of the composite by enhancing the electrical conductivity, forming a flexible network, and providing extra lithium storage sites. The obtained composites were tested for electrochemical performance for a total number of 2120 cycles: a rate capability test with current densities ranged from 90 to 7200 mA g-1 for 920 cycles, followed by a cycling test at 1800 mA g-1 for 1200 cycles. For the rate capability test, steady reversible capacities were delivered under each current density with final reversible capacities of 1177, 1096, 833, 488, 242, and 146 mA h g-1 at 90, 180, 900, 1800, 3600, and 7200 mA g-1, respectively. The subsequent cyclic test demonstrated the superior cyclic stability of USIO/G and a reversible capacity of 437 mA h g-1 at the 2120th cycle was delivered. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01826a

Chen, Yu; Song, Bohang; Lu, Li; Xue, Junmin

2013-07-01

130

Effect of magnetic Fe3O4 nanoparticles with 2-methoxyestradiol on the cell-cycle progression and apoptosis of myelodysplastic syndrome cells  

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This study aims to evaluate the potential benefit of combination therapy of 2-methoxyestradiol (2ME) and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) on myelodysplastic syndrome (MDS) SKM-1 cells and its underlying mechanisms. The effect of the unique properties of tetraheptylammonium-capped MNPs-Fe3O4 with 2ME on cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle distribution and apoptosis were assessed by flow cytometry. The expression ...

Xia, Guohua; Chen, Baoan; Ding, Jiahua; Gao, Chong; Lu, Huixia; Shao, Zeye; Gao, Feng; Wang, Xuemei

2011-01-01

131

Effect of natural Fe3O4 nanoparticles on structural and optical properties of Er3+ doped tellurite glass  

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Control doping of magnetic nanoparticles and its influence on optical and structural properties of tellurite glass is important from device perspectives. Natural Fe3O4 nanoparticles obtained by extracting and ball milling iron sand, are incorporated in the Er3+ doped tellurite glasses having composition (80?x)TeO2·xFe3O4·18ZnO·1Li2O·1Er2O3 (0?x?1.5) in mol% by melt quenching method at 850 °C. X-Ray diffraction spectra confirms the presence of iron nanoparticles with estimated sizes 18–70 nm and an amorphous structure of the samples. Thermal and optical characterizations are made using diffential thermal analysis, ultraviolet–visible and photoluminescence spectrocopies. It is found that the presence of nanoparticles changes color and thermal stability of the glasses, which is proved by increasing thermal stability factor from 118 to 132 °C. Absorption spectra consist of six peaks corresponding to different transition from ground state to the excited states in which the quench of the peak associated with 4F1/2 is attributed to the effect nanoparticles. Moreover, the shift in the absorption edge from ?400 to ?500 nm indicates a significant decrease of the optical energy band gap for both direct and indirect allowed transitions and a decrease in the Urbach energy as much as 0.116 eV is observed. The room temperature down-conversion luminescence spectra obtained under 500 nm excitation exhibit two strong peaks related to excited states 4S3/2 and 4F9/2 of Er3+ ions in the absence of nanoparticles. Furthermore, embedding nanoparticles into the glass not only make the peaks weaker but the second peak completely disappears. Interestingly, the emission bands of the Er3+ ion are quenched as concentration of the magnetic nanoparticles is increased.

2013-01-01

132

Radiolytic Formation of Fe3O4 Nanoparticles: Influence of Radiation Dose on Structure and Magnetic Properties  

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Colloidal Fe3O4 nanoparticles were synthesized using a gamma-radiolysis method in an aqueous solution containing iron chloride in presence of polyvinyl alcohol and isopropanol as colloidal stabilizer and hydroxyl radical scavenger, respectively. Gamma irradiation was carried out in a 60Co gamma source chamber at different absorbed doses. Increasing the radiation dose above a certain critical dose (100 kGy) leads to particle agglomeration enhancement, and this can influence the structure and crystallinity, and consequently the magnetic properties of the resultant particles. The optimal condition for formation of Fe3O4 nanoparticles with a uniform and narrow size distribution occurred at a dose of 100 kGy, as confirmed by X-ray diffractometry and transmission electron microscopy. A vibrating sample magnetometry study showed that, when radiation dose increased, the saturation and remanence magnetization decreased, whereas the coercivity and the remanence ratio increased. This magnetic behavior results from variations in crystallinity, surface effects, and particle size effects, which are all dependent on the radiation dose. In addition, Fourier transform infrared spectroscopy was performed to investigate the nature of the bonds formed between the polymer chains and the metal surface at different radiation doses.

Abedini, Alam; Daud, Abdul Razak; Abdul Hamid, Muhammad Azmi; Kamil Othman, Norinsan

2014-01-01

133

Dextran-coated Fe3O4 magnetic nanoparticles as a contrast agent in thermoacoustic tomography for hepatocellular carcinoma detection  

International Nuclear Information System (INIS)

Microwave-induced thermoacoustic tomography can provide a novel imaging modality for clinical detection. Significant progress has been made in the past several years in microwave-induced thermoacoustic tomography. In this paper, we investigate the feasibility of using dextran-coated Fe3O4 magnetic nanoparticles as a contrast agent in thermoacoustic tomography for hepatocellular carcinoma detection. Dextran-coated Fe3O4 magnetic nanoparticles administered intravenously are phagocytosed by resident Kupffer cells in normal reticuloendothelial system (RES) within the liver, but are not retained in tumor tissue. Consequently, there are significant differences in thermoacoustic signal intensity between normal RES and tumors, which result in increased lesion conspicuity and detectability. This provides the improvement of lesion-to-liver contrast for thermoacoustic tomography. A fast thermoacoustic computed tomography system with a multielement linear transducer array was used to image cancerous liver tissue with circular scanning. The results show that the system can provide molecular imaging with functionalized contrast agents for high-contrast detecting hepatocellular carcinoma and has the potential to become a novel approach for clinical diagnosis in the future.

2011-01-01

134

Facile Preparation of One-Dimensional Wrapping Structure: Graphene Nanoscroll-Wrapped of Fe3O4 Nanoparticles and Its Application for Lithium-Ion Battery.  

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Graphene nanoscroll (GNS) is a spirally wrapped two-dimensional (2D) graphene sheet (GS) with a 1D tubular structure resembling that of a multiwalled carbon nanotube (MWCNT). GNS provide open structure at both ends and interlayer galleries that can be easily intercalated and adjusted, which show great potential applications in energy storage. Here we demonstrate a novel and simple strategy for the large-scale preparation of GNSs wrapping Fe3O4 nanoparticles (denoted as Fe3O4@GNSs) from graphene oxide (GO) sheets by cold quenching in liquid nitrogen. When a heated aqueous mixed suspension of GO sheets and Fe3O4 nanoparticles is immersed in liquid nitrogen, the in-situ wrapping of Fe3O4 nanoparticles with GNSs is easily realized. The structural conversion is closely correlated with the initial temperature of mixed suspension, the zeta potential of Fe3O4 nanoparticles and the immersion way. Remarkably, such hybrid structure provides the right combination of electrode properties for high-performance lithium-ion batteries. Compared with other wrapping structure, such 1D wrapping structure (GNSs wrapping) effectively limits the volume expansion of Fe3O4 nanoparticles during the cycling process, consequently, a high reversible capacity, good rate capability, and excellent cyclic stability are achieved with the material as anode for lithium storage. The results presented here may pave a way for the large-scale preparation of GNS-based materials in electrochemical energy storage applications. PMID:24826777

Zhao, Jinping; Yang, Bingjun; Zheng, Zongmin; Yang, Juan; Yang, Zhi; Zhang, Peng; Ren, Wencai; Yan, Xingbin

2014-06-25

135

The synthesis and properties of bifunctional and intelligent Fe3O4@titanium oxide core/shell nanoparticles.  

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A simple, one-pot solvothermal method has been demonstrated for the preparation of bifunctional Fe3O4@titanium oxide core/shell nanoparticles. In a typical procedure, tetraalkoxyl titanium Ti(OC4H9)4 and FeCl3 as precursors were added into ethylene glycol and further solvothermal treatment was used to synthesize the core/shell particles. The core/shell particles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), SQUID MPMS and rheometry. The morphological results showed titanium oxide nanorods with 100-200 nm length and 10-20 nm diameter coated on the surface of 200-300 nm Fe3O4 submicrospheres. Reaction time, the titanium source, the barium salt etc. have an influence on the morphology of core/shell particles. The core/shell particles can not only respond to an external magnetic field, but also to an electric field--a novel application of electrorheological fluid. PMID:23532087

Yin, Yichao; Liu, Chenjie; Wang, Baoxiang; Yu, Shoushan; Chen, Kezheng

2013-05-21

136

Covalent TiO(2)/pectin microspheres with Fe(3)O(4) nanoparticles for magnetic field-modulated drug delivery.  

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Covalent TiO(2)-co-pectin microspheres containing Fe(3)O(4) nanoparticles were developed through an ultrasound-induced crosslinking/polymerization reaction between the glycidyl methacrylate from vinyl groups in TiO(2) and in pectin. ?-potentials became less negative in the nanostructured microspheres, caused by the presence of both inorganic particles in the negatively charged pectin. The nanostructured pectin microspheres showed an amoxicillin release rate slower than that of pure pectin microspheres. The proposed microspheres were found to be a sustained release system of amoxicillin in the acid medium. Furthermore, the antibiotic release may be modulated by exposition of the microspheres to a remote magnetic field. In practical terms, the nanostructured microspheres could deliver a larger proportion of their initial load to specific site of action. The cytotoxic concentrations for 50% of VERO cells (CC(50)), calculated as the concentration required to reduce cell viability by 50% after 72h of incubation, for pectin-only microspheres and nanostructured pectin microspheres were 217.7±6.5 and 121.5±4.9?gmL(-1), respectively. The obtained CC(50) values indicated acceptable cytotoxic levels for an incubation period of 72h, showing that the pectin microspheres have a great pharmacological potential for uses in biological environments, even after the introduction of both Fe(3)O(4) and TiO(2). PMID:24565898

da Silva, Elisangela P; Sitta, Danielly L A; Fragal, Vanessa H; Cellet, Thelma S P; Mauricio, Marcos R; Garcia, Francielle P; Nakamura, Celso V; Guilherme, Marcos R; Rubira, Adley F; Kunita, Marcos H

2014-06-01

137

One-step synthesis Fe3N surface-modified Fe3O4 nanoparticles with excellent lithium storage ability  

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The Fe3N modified Fe3O4 nanoparticles with an excellent performance in lithium-ion batteries were prepared via a one-step and an efficient method. The layer of Fe3N could significantly decrease the variation of volume and enhance the conductivity of Fe3O4 simultaneously during the reaction of lithium ions in the charge-discharge process. There are two main advantages of this material: (1) their size distribution, ranging from 100 to 500 nm and (2) the fact that these particles are connected with each other by the Fe3N layer. These two features allow such material to exhibit a high reversible capacity of 739 and 620 mA h g-1 after each 60 cycles at the current density of 50 and 200 mA g-1, respectively. More importantly, since its introduction, this new concept of coating metal oxides with a layer of metal nitride to form core-shell structured metal oxide@metal nitride can be widely applied in the fields of catalysis, electrochemistry, energy, environmental and materials science with improved performance.

Li, Yabin; Yan, Yuerong; Ming, Hai; Zheng, Junwei

2014-06-01

138

Preparation and characterization of magnetic Fe3O 4/CNT nanoparticles by RPO method to enhance the efficient removal of Cr(VI).  

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This work described a novel method for the synthesis of high-ferromagnetism nanoparticles (Fe3O4/CNTs) to efficiently remove Cr(VI) from aqueous solution. The Fe3O4/carbon nanotubes (CNTs) were prepared by in situ reduction with post-oxidation method by using cheap and environmentally friendly precursor under mild condition. Magnetic hysteresis loops revealed that Fe3O4/CNTs had superior saturation magnetization (152 emu/g), enabling the highly efficient recovery of Fe3O4/CNTs from aqueous solution by magnetic separation at low magnetic field gradients. FTIR, Raman, XPS, and TEM observations were employed to characterize the physical-chemical properties of Fe3O4/CNTs, demonstrating that CNTs were successfully coated with iron oxide matrix. The adsorption equilibrium of Cr(VI) on Fe3O4/CNTs was reached within 30 min. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm were chosen to analyze the equilibrium data. The results indicated that Langmuir model can well describe the equilibrium data with the maximum adsorption capacity of 47.98 mg/g at room temperature and 83.54 mg/g at 353 K. The adsorption capacity of Fe3O4/CNTs for Cr(VI) was greatly improved as compared to raw CNTs and other similar adsorbents reported. The pseudo-second-order kinetic model provided the best description of Cr(VI) adsorption on Fe3O4/CNTs. Most importantly, possible synthesis mechanism and Cr(VI) removal mechanism were explored. The results suggest that large amounts of Cr(VI) were adsorbed on Fe3O4/CNTs surface by substituting the surface position of -OH and then reducing it to Cr(OH)3 and Cr2O3. PMID:23644945

Chen, Runhua; Chai, Liyuan; Li, Qinzhu; Shi, Yan; Wang, Yangyang; Mohammad, Ali

2013-10-01

139

Preparation and characterization of magnetic nanoparticles containing Fe3O4-dextran- anti-?-human chorionic gonadotropin, a new generation choriocarcinoma-specific gene vector  

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Cai Jingting1,2, Liu Huining1, Zhang Yi11Department of Obstetrics and Gynecology, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 2Department of Gynecological Oncology, Hunan Tumor Hospital, Changsha, Hunan, People’s Republic of ChinaObjective: To evaluate the feasibility of using magnetic iron oxide (Fe3O4)-dextran-anti-?-human chorionic gonadotropin (HCG) nanoparticles as a gene vector for cellular transfections.Study design: Fe3O4-d...

2011-01-01

140

Preparation of Fe3O4-Embedded Poly(styrene/Poly(thiophene Core/Shell Nanoparticles and Their Hydrogel Patterns for Sensor Applications  

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Full Text Available This research describes the preparation and sensor applications of multifunctional monodisperse, Fe3O4 nanoparticles-embedded poly(styrene/poly(thiophene (Fe3O4-PSt/PTh, core/shell nanoparticles. Monodisperse Fe3O4-PSt/PTh nanoparticles were prepared by free-radical combination (mini-emulsion/emulsion polymerization for Fe3O4-PSt core and oxidative seeded emulsion polymerization for PTh shell in the presence of FeCl3/H2O2 as a redox catalyst, respectively. For applicability of Fe3O4-PSt/PTh as sensors, Fe3O4-PSt/PTh-immobilized poly(ethylene glycol (PEG-based hydrogels were fabricated by photolithography. The hydrogel patterns showed a good sensing performance under different H2O2 concentrations. They also showed a quenching sensitivity of 1 µg/mL for the Pd2+ metal ion within 1 min. The hydrogel micropatterns not only provide a fast water uptake property but also suggest the feasibility of both H2O2 and Pd2+ detection.

Yong Seok Kim

2014-01-01

 
 
 
 
141

The effect of initial alignment on the optical properties of Fe3O4 nanoparticles doped in nematic liquid crystals  

International Nuclear Information System (INIS)

Recently the nonlinear effects of the different materials doped liquid crystals are more interesting. In all previous works, nonlinearity of samples with the homeotropic alignment is investigated because of the larger component of the refractive index in this direction. Here, there are spherical Fe3O4 nanoparticles that have both parallel and perpendicular components. We were looking for the effect of initial alignment on the nonlinearity of pure and doped nematic liquid crystals (NLCs). The experimental results emphasize, even the same compositional percentage of nanoparticles prepared by two different alignment configurations are showing different results when dispersed in the same NLCs. Comparing nonlinear studies, the magnitude of nonlinear refraction index, n2 and nonlinear absorption coefficient, ? increase 102 and 101 times, respectively, in homeotropic alignment samples and the sign of these parameters is changed rather than homogeneous ones

2014-02-01

142

The effect of initial alignment on the optical properties of Fe3O4 nanoparticles doped in nematic liquid crystals  

Science.gov (United States)

Recently the nonlinear effects of the different materials doped liquid crystals are more interesting. In all previous works, nonlinearity of samples with the homeotropic alignment is investigated because of the larger component of the refractive index in this direction. Here, there are spherical Fe3O4 nanoparticles that have both parallel and perpendicular components. We were looking for the effect of initial alignment on the nonlinearity of pure and doped nematic liquid crystals (NLCs). The experimental results emphasize, even the same compositional percentage of nanoparticles prepared by two different alignment configurations are showing different results when dispersed in the same NLCs. Comparing nonlinear studies, the magnitude of nonlinear refraction index, n2 and nonlinear absorption coefficient, ? increase 102 and 101 times, respectively, in homeotropic alignment samples and the sign of these parameters is changed rather than homogeneous ones.

Dehghani, Z.; Iranizad, E. Saievar

2014-02-01

143

One-step hydrothermal process to prepare highly crystalline Fe3O4 nanoparticles with improved magnetic properties  

International Nuclear Information System (INIS)

Hydrothermal process was successfully used to synthesize Fe3O4 powder using ferrous chloride (FeCl2) and diamine hydrate (H4N2·H2O) as starting materials by carefully controlling the reaction conditions. The as-prepared Fe3O4 sample was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and its magnetic properties were evaluated on a vibrating sample magnetometer (VSM). The nanoscale (40 nm) Fe3O4 powder obtained at 140 deg. C for 6 h possessed a saturation magnetization of 85.8 emu/g, a little lower than that of the correspondent bulk Fe3O4 (92 emu/g). It is suggested that the well-crystallized Fe3O4 grains formed under appropriate hydrothermal conditions should be responsible for the increased saturation magnetization in nanosized Fe3O4

2003-06-19

144

Reversal of multidrug resistance by cisplatin-loaded magnetic Fe3O4 nanoparticles in A549/DDP lung cancer cells in vitro and in vivo  

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Full Text Available Ke Li,1 Baoan Chen,1,2 Lin Xu,3 Jifeng Feng,3 Guohua Xia,1,2 Jian Cheng,1,2 Jun Wang,1,2 Feng Gao,1,2 Xuemei Wang,41Department of Hematology, Key Medical Disciplines of Jiangsu Province, Zhongda Hospital, Medical School, Southeast University, Nanjing, 2Faculty of Oncology, Medical School, Southeast University, Nanjing, 3Department of Thoracic Surgery, Jiangsu Province Cancer Hospital, Jiangsu Province, 4State Key Laboratory of Bioelectronics, Southeast University, Nanjing, People’s Republic of ChinaAbstract: The purpose of this study was to explore whether magnetic Fe3O4 nanoparticles (Fe3O4-MNP loaded with cisplatin (Fe3O4-MNP-DDP can reverse DDP resistance in lung cancer cells and to investigate mechanisms of multidrug resistance in vitro and in vivo. MTT assay showed that DDP inhibited both A549 cells and DDP-resistant A549 cells in a time-dependent and dose-dependent manner, and that this inhibition was enhanced by Fe3O4-MNP. An increased rate of apoptosis was detected in the Fe3O4-MNP-DDP group compared with a control group and the Fe3O4-MNP group by flow cytometry, and typical morphologic features of apoptosis were confirmed by confocal microscopy. Accumulation of intracellular DDP in the Fe3O4-MNP-DDP group was greater than that in the DDP group by inductively coupled plasma mass spectrometry. Further, lower levels of multidrug resistance-associated protein-1, lung resistance-related protein, Akt, and Bad, and higher levels of caspase-3 genes and proteins, were demonstrated by reverse transcriptase polymerase chain reaction and Western blotting in the presence of Fe3O4-MNP-DDP. We also demonstrated that Fe3O4-MNP enhanced the effect of DDP on tumor growth in BALB/c nude mice bearing DDP-resistant human A549 xenografts by decreasing localization of lung resistance-related protein and Ki-67 immunoreactivity in cells. There were no apparent signs of toxicity in the animals. Overall, these findings suggest potential clinical application of Fe3O4-MNP-DDP to increase cytotoxicity in lung tumor xenografts.Keywords: Fe3O4, nanoparticles, multidrug resistance, reversal, DDP-resistant A549 cells, cisplatin

Li K

2013-05-01

145

Pluronic@Fe3O4 nanoparticles with robust incorporation of doxorubicin by thermo-responsiveness.  

Science.gov (United States)

Doxorubicin was physically incorporated in magnetic nanoparticles by thermo-responsive manners. Magnetic nanoparticles were prepared by oxidizing ferric ions in ammonium solution. Thiolated Pluronic was synthesized by sequential modification of terminal hydroxyl groups of Pluronic to amine groups and thiol groups. Magnetic nanoparticles composed of iron oxide were surface-modified with thiolated Pluronic at different molar ratios of iron to thiol groups. Pluronic decoration on the magnetic nanoparticles was characterized by elemental analysis and transmission electron microscopy. Elemental analysis results on carbon atoms in the magnetic nanoparticles showed that the degree of Pluronic decoration was proportional to the feed ratio of thiolated Pluronic to iron oxide. Doxorubicin was incorporated to the magnetic nanoparticles thermo-responsive manners; a mixture of hydrophobized doxorubicin and the magnetic nanoparticles was incubated at 4°C and the temperature was subsequently increased to 37°C for thermally induced structural changes of the decorated Pluronic moieties. Doxorubicin-incorporated magnetic nanoparticles showed dramatic modulations of size distributions according to temperature changes, which was dependent on the degree of Pluronic decoration. Loading efficiency of doxorubicin was significantly affected by the number of decorated Pluronic on the magnetic nanoparticles; the higher Pluronic moieties the nanoparticles had, the higher loading efficiency they showed. Release profiles of doxorubicin from the nanoparticles showed that doxorubicin was liberated from the nanoparticles in response to reducing conditions of the release medium. Anti-cancer activities of the doxorubicin-incorporated nanoparticles were determined by a MTT-based cytotoxicity assay against A549 cell lines. Compared to native doxorubicin, the doxorubicin incorporated magnetites showed attenuated cytotoxicities due to slow release of doxorubicin from the carriers. Thus, thermally induced incorporation of anti-cancer drugs can be a novel method for multifunctional magnetic nanoparticles with imaging and anti-cancer treatments. PMID:22226875

Park, Shinyoung; Kim, Hye Sung; Kim, Woo Jin; Yoo, Hyuk Sang

2012-03-15

146

Preparation and in vitro evaluation of doxorubicin-loaded Fe3O4 magnetic nanoparticles modified with biocompatible copolymers  

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Full Text Available Abolfazl Akbarzadeh1, Haleh Mikaeili2, Nosratollah Zarghami3, Rahmati Mohammad3, Amin Barkhordari3, Soodabeh Davaran21Drug Applied Research Center, 2Tuberculosis and Lung Disease Research Center of Tabriz, 3Department of Clinical Biochemistry and Laboratory Medicine, Division of Medical Biotechnology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IranBackground: Superparamagnetic iron oxide nanoparticles are attractive materials that have been widely used in medicine for drug delivery, diagnostic imaging, and therapeutic applications. In our study, superparamagnetic iron oxide nanoparticles and the anticancer drug, doxorubicin hydrochloride, were encapsulated into poly (D, L-lactic-co-glycolic acid poly (ethylene glycol (PLGA-PEG nanoparticles for local treatment. The magnetic properties conferred by superparamagnetic iron oxide nanoparticles could help to maintain the nanoparticles in the joint with an external magnet.Methods: A series of PLGA:PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide with different molecular weights of polyethylene glycol (PEG2000, PEG3000, and PEG4000 as an initiator. The bulk properties of these copolymers were characterized using 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and differential scanning calorimetry. In addition, the resulting particles were characterized by x-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry.Results: The doxorubicin encapsulation amount was reduced for PLGA:PEG2000 and PLGA:PEG3000 triblock copolymers, but increased to a great extent for PLGA:PEG4000 triblock copolymer. This is due to the increased water uptake capacity of the blended triblock copolymer, which encapsulated more doxorubicin molecules into a swollen copolymer matrix. The drug encapsulation efficiency achieved for Fe3O4 magnetic nanoparticles modified with PLGA:PEG2000, PLGA:PEG3000, and PLGA:PEG4000 copolymers was 69.5%, 73%, and 78%, respectively, and the release kinetics were controlled. The in vitro cytotoxicity test showed that the Fe3O4-PLGA:PEG4000 magnetic nanoparticles had no cytotoxicity and were biocompatible.Conclusion: There is potential for use of these nanoparticles for biomedical application. Future work includes in vivo investigation of the targeting capability and effectiveness of these nanoparticles in the treatment of lung cancer.Keywords: superparamagnetic iron oxide nanoparticles, triblock copolymer, doxorubicin encapsulation, water uptake, drug encapsulation efficiency

Akbarzadeh A

2012-02-01

147

Sensitive electrochemical sensor for hydrogen peroxide using Fe3O4 magnetic nanoparticles as a mimic for peroxidase  

International Nuclear Information System (INIS)

A sensor for hydrogen peroxide is described that is based on an indium tin oxide electrode modified with Fe3O4 magnetic nanoparticles which act as a mimic for the enzyme peroxidase and greatly improve the analytical performance of the sensor. The amperometric current is linearly related to the concentration of H2O2 in the range from 0.2 mM to 2 mM, the regression equation is y = -0.5-1.82x, the correlation coefficient is 0.998 (n = 3), and the detection limit is 0.01 mM (S/N = 3). The sensor exhibits favorable selectivity and excellent stability. (author)

2011-07-01

148

Solution-processed Fe3O4 magnetic nanoparticle thin film aligned by an external magnetostatic field as a hole extraction layer for polymer solar cells.  

Science.gov (United States)

We report, for the first time, the effect of a solution-processed Fe3O4 magnetic nanoparticle (MNP) thin film and a Fe3O4 MNP thin film aligned by an external magnetostatic field, used as a hole extraction layer (HEL), respectively, in polymer solar cells (PSCs). The thin film of a Fe3O4 MNP shows a smoother surface, better transparency, and higher electrical conductivity than that of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin layer. Moreover, the thin film of a Fe3O4 MNP aligned by an external magnetostatic field possesses an enhanced electrical conductivity and lower internal series resistance, thus leading to greater than 13% enhancement in the power conversion efficiency of PSCs than those using a PEDOT:PSS thin film. It was also found that PSCs incorporated with a Fe3O4 MNP shows better stability compared with those using PEDOT:PSS as an anode buffer layer. These results demonstrated that utilization of a Fe3O4 MNP as a HEL in PSCs blazes a trail to achieve highly efficient and long-time-stable devices. PMID:24063636

Wang, Kai; Ren, He; Yi, Chao; Liu, Chang; Wang, Hangxing; Huang, Lin; Zhang, Haoli; Karim, Alamgir; Gong, Xiong

2013-10-23

149

Synthesis and functionalization of SiO2 coated Fe3O4 nanoparticles with amine groups based on self-assembly  

International Nuclear Information System (INIS)

The purpose of this research was to synthesize amino modified Fe3O4/SiO2 nanoshells for biomedical applications. Magnetic iron-oxide nanoparticles (NPs) were prepared via co-precipitation. The NPs were then modified with a thin layer of amorphous silica. The particle surface was then terminated with amine groups. The results showed that smaller particles can be synthesized by decreasing the NaOH concentration, which in our case this corresponded to 35 nm using 0.9 M of NaOH at 750 rpm with a specific surface area of 41 m2 g?1 for uncoated Fe3O4 NPs and it increased to about 208 m2 g?1 for 3-aminopropyltriethoxysilane (APTS) coated Fe3O4/SiO2 NPs. The total thickness and the structure of core-shell was measured and studied by transmission electron microscopy (TEM). For uncoated Fe3O4 NPs, the results showed an octahedral geometry with saturation magnetization range of (80–100) emu g?1 and coercivity of (80–120) Oe for particles between (35–96) nm, respectively. The Fe3O4/SiO2 NPs with 50 nm as particle size, demonstrated a magnetization value of 30 emu g?1. The stable magnetic fluid contained well-dispersed Fe3O4/SiO2/APTS nanoshells which indicated monodispersity and fast magnetic response.

2012-07-01

150

One pot synthesis of water-dispersible dehydroascorbic acid coated Fe3O4 nanoparticles under atmospheric air: Blood cell compatibility and enhanced magnetic resonance imaging.  

Science.gov (United States)

Water dispersible and biologically important molecule dehydroascorbic acid (DHA, capable to cross the blood brain barrier) coated Fe3O4 superparamagnetic nanoparticles having an average size of ?6nm were synthesized through one pot aqueous coprecipitation method under atmospheric air. An antioxidant ascorbic acid (AA) used in the synthesis oxidized itself to dehydroascorbic acid (DHA) to consume dissolved or available oxygen in reaction mixture which died away the oxidative impact of atmospheric air and formed DHA encapsulated the Fe3O4 nanoparticles which stabilized the Fe3O4 nanoparticles and significantly enhanced their colloidal solubility in water. Fe3O4 phase, superparamagnetic property, DHA coating and stable colloidal solubility in water were confirmed by means of XPS, VSM, IR and zeta potential analysis respectively. T1, T2 and T2(?) weighted magnetic resonance imaging (MRI) and corresponding relaxivity (r1=0.416, r2=50.28 and r2(?)=123.65mM(-1) and r2/r1=120.86, r2(?)r1=297.23) of colloidally dispersed DHA-coated nanoparticle water phantom revealed a strong contrast enhancement in T2 and T2(?) weighted images. The compatibility of DHA-coated Fe3O4 nanoparticles toward human blood cells was examined by means of cell counting and cell morphological analysis with the use of optical microscope and scanning electron microscope imaging. PMID:24956575

Gupta, Hariom; Paul, P; Kumar, Naresh; Baxi, Seema; Das, Dipti P

2014-09-15

151

Amperometric glucose sensor based on enhanced catalytic reduction of oxygen using glucose oxidase adsorbed onto core-shell Fe3O4-silica-Au magnetic nanoparticles  

International Nuclear Information System (INIS)

Monodisperse Fe3O4 magnetic nanoparticles (NPs) were prepared under facile solvothermal conditions and successively functionalized with silica and Au to form core/shell Fe3O4-silica-Au NPs. Furthermore, the samples were used as matrix to construct a glucose sensor based on glucose oxidase (GOD). The immobilized GOD retained its bioactivity with high protein load of 3.92 × 10?9 mol·cm?2, and exhibited a surface-controlled quasi-reversible redox reaction, with a fast heterogeneous electron transfer rate of 7.98 ± 0.6 s?1. The glucose biosensor showed a broad linear range up to 3.97 mM with high sensitivity of 62.45 ?A·mM?1 cm?2 and fast response (less than 5 s). - Graphical abstract: Core-shell structured Fe3O4-silica-Au nanoparticles were prepared and used as matrix to construct an amperometric glucose sensor based on glucose oxidase, which showed broad linear range, high sensitivity, and fast response. Highlights: ? Synthesis of monodispersed Fe3O4 nanoparticles. ? Fabrication of core/shell Fe3O4-silica-Au nanoparticles. ? Construction of a novel glucose sensor with wide linear range, high sensitivity and fast response.

2012-08-01

152

Preparation and assessment of chitosan-coated superparamagnetic Fe3O4 nanoparticles for controlled delivery of methotrexate.  

Science.gov (United States)

In this study, Fe3O4 superparamagnetic nanoparticles were synthesized and stabilized by chitosan. Then the nanoparticles were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). Particle size distribution and Zeta potential of the particles also was assessed using Malvern Zetasizer. The paramagnetic behaviors of the uncoated and chitosan coated nanoparticles were measured using vibrating scanning magnetometry Particles morphology and size ranges of uncoated iron oxide nanoparticles were evaluated by TEM, showing uniform and narrow size distribution about 10 nm. After coating nanoparticles with chitosan and loading of methotrexate (MTX), the change in size was assessed using Zetasizer. Considerable increase in size was observed following the coating of the particles with chitosan and loading with MTX (the average size was 152 nm). Paramagnetic properties of the uncoated and chitosan-coated particles were assessed showing significant decrease in paramagnetic behavior after coating with chitosan, but it was enough to respond to the magnetic field. Finally loading efficiency, release rate and cytotoxicity of MTX were assessed indicating slow release behavior with the same levels of cell toxicity in SK-BR-3 cell lines, suggesting this formulation as a good candidate for the controlled delivery of MTX. PMID:24459473

Mohammadi-Samani, S; Miri, R; Salmanpour, M; Khalighian, N; Sotoudeh, S; Erfani, N

2013-01-01

153

CdS urchin-like microspheres/?-Fe2O3 and CdS/Fe3O4 nanoparticles heterostructures with improved photocatalytic recycled activities.  

Science.gov (United States)

The heterostructures of three-dimensional CdS urchin-like microspheres separately decorated with hematite ?-Fe2O3 or magnetite Fe3O4 nanoparticles were successfully synthesized via a two-step solvothermal deposition. Each CdS urchin-like microspheres had an average diameter of 2?m, which was composed of nanorods with average diameters of 10nm. ?-Fe2O3 and Fe3O4 nanoparticles, with diameters of about 20nm and 30nm, respectively, anchored on the nanorods of CdS urchins. The photoluminescence behaviors of CdS urchins were conserved in both CdS/?-Fe2O3 and CdS/Fe3O4 heteronanostructures, and CdS/Fe3O4 heteronanostructure displayed ferromagnetic properties of the Fe3O4 nanoparticles, which makes it easily magnetically separated from the dispersion after photocatalysis and hence reused. Furthermore, the CdS/?-Fe2O3 heteronanostructure exhibited superior photocatalytic performances under visible light irradiation over pure CdS urchins and both the heteronanostructures showed improved photocatalytic recycled activities. PMID:24863769

Wu, Zhengcui; Yu, Hao; Kuai, Long; Wang, Huan; Pei, Tonghui; Geng, Baoyou

2014-07-15

154

Synthesis and characterization of L10 FePt nanoparticles from Pt-Fe3O4 core-shell nanoparticles  

International Nuclear Information System (INIS)

Pt/Fe3O4 core-shell nanoparticles have been prepared by a modified polyol method. Pt nanoparticles were first prepared via the reduction of Pt(acac)2 by polyethylene glycol-200 (PEG-200), and layers of iron oxide were subsequently deposited on the surface of Pt nanoparticles by the thermal decomposition of Fe(acac)3. The nanoparticles were characterized by XRD and HR-TEM. The as-prepared Pt/Fe3O4 nanoparticles have a chemically disordered FCC structure and transformed into chemically ordered fct structure after annealing in reducing atmosphere (4% H2, 96% Ar) at 700 deg C. The ordered fct FePt phase has high magnetic anisotropy with coercivity reaching 7.5 kOe at room temperature and 9.3 kOe at 10 K

2005-07-01

155

Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping  

Energy Technology Data Exchange (ETDEWEB)

Magnetic (Ga{sub x}Fe{sub 1-x}){sub 3}O{sub 4} nanoparticles with 5%-33% gallium doping (x = 0.05-0.33) were measured using x-ray absorption spectroscopy and x-ray magnetic circular dichroism to determine that the Ga dopant is substituting for Fe{sub 3+} as Ga{sub 3+} in the tetrahedral A-site of the spinel structure, resulting in an overall increase in the total moment of the material. Frequency-dependent alternating-current magnetic susceptibility measurements showed these particles to be weakly interacting with a reduction of the cubic anisotropy energy term with Ga concentration. The element-specific dichroism spectra show that the average Fe moment is observed to increase with Ga concentration, a result consistent with the replacement of A-site Fe by Ga.

Pool, V. L.; Klem, M. T.; Chorney, C. L.; Arenholz, E.; Idzerda, Y.U.

2010-10-22

156

Reversal in multidrug resistance by magnetic nanoparticle of Fe3O4 loaded with adriamycin and tetrandrine in K562/A02 leukemic cells  

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Drug resistance is a primary hindrance for efficiency of chemotherapy. To investigate whether Fe3O4-magnetic nanoparticles (Fe3O4-MNPs) loaded with adriamycin (ADM) and tetrandrine (Tet) would play a synergetic reverse role in multidrug resistant cell, we prepared the drug-loaded nanoparticles by mechanical absorption polymerization to act with K562 and one of its resistant cell line K562/A02. The survival of cells which were cultured with these conjugates for 48 h was observed by MTT assay. ...

Chen, Baoan; Sun, Qian; Wang, Xuemei; Gao, Feng; Dai, Yongyuan; Yin, Yan; Ding, Jiahua; Gao, Chong; Cheng, Jian; Li, Jingyuan; Sun, Xinchen; Chen, Ningna; Xu, Wenlin; Shen, Huiling; Liu, Delong

2008-01-01

157

The optimum conditions for synthesis of Fe3O4/ZnO core/shell magnetic nanoparticles for photodegradation of phenol.  

Science.gov (United States)

The photocatalysis of phenol was studied using Fe3O4/ZnO core/shell magnetic nanoparticles (MNPs). The photocatalysts were synthesized by coating of ZnO onto the magnetite by precipitation method and characterized by XRD, SEM and FTIR measurements. Using the Taguchi method, this study analyzes the effect of parameters such as calcinations time, calcinations temperature and molar ratio of Fe3O4:ZnO on the photo activity of Fe3O4/ZnO MNPs. XRD and FTIR analysis confirm that coating process was done successfully. SEM images show that the average particle size of synthesized Fe3O4/ZnO nanoparticles was about 50 nm. The phenol removal efficiency of 88% can be achieved by using a photocatalyst which is synthesized through the optimum conditions: calcinations temperature of 550°C, calcinations time of 2 hours and molar ratio of 1:10 for Fe3O4:ZnO. PMID:24406040

Nikazar, Manouchehr; Alizadeh, Mehriana; Lalavi, Reza; Rostami, Mohammad Hossein

2014-01-01

158

Multifunctional nanocomposites of superparamagnetic (Fe3O4) and NIR-responsive rare earth-doped up-conversion fluorescent (NaYF4 : Yb,Er) nanoparticles and their applications in biolabeling and fluorescent imaging of cancer cells  

Science.gov (United States)

A new kind of magnetic/luminescent multifunctional nanoparticles was synthesized by covalently linking multiple carboxyl-functionalized superparamagnetic Fe3O4 nanoparticles and individual amino-functionalized silica-coated fluorescent NaYF4 : Yb,Er up-conversion nanoparticles (UCNPs). The resultant nanocomposites bear active carboxylic and amino groups on the surface that were proved to be chemically active and useful for further facile bioconjugation with biomolecules. The UCNPs in the nanocomposite particles can emit visible light in response to the irradiation by near infrared (NIR) light, enabling the application of the nanocomposites in bioimaging. X-Ray diffraction, infrared spectroscopy, transmission electron microscopy, luminescence spectroscopy, and magnetometry were applied to characterize the multifunctional nanocomposites. The nanocomposites exhibited good superparamagnetic and excellent green up-conversion photoluminescent properties that can be exploited in magnetic separation and guiding as well as bioimaging. Due to the presence of active functional groups on the nanocomposite surface, the Fe3O4/NaYF4 : Yb,Er magnetic/luminescent nanocomposites were successfully conjugated with a protein called transferrin, which specifically recognizes the transferrin receptors overexpressed on HeLa cells, and can be employed for biolabeling and fluorescent imaging of HeLa cells. Because NIR light can penetrate biological samples with good depth without damaging them and can avoid autofluorescence from them, the presence of both NIR-responsive UCNPs and superparamagnetic nanoparticles in the nanocomposite particles will enable the practical application of the nanocomposites in bioimaging and separation.

Mi, Congcong; Zhang, Jingpu; Gao, Huanyu; Wu, Xianlong; Wang, Meng; Wu, Yingfan; di, Yueqin; Xu, Zhangrun; Mao, Chuanbin; Xu, Shukun

2010-07-01

159

Labeling primary amine groups in peptides and proteins with N-hydroxysuccinimidyl ester modified Fe3O4@SiO2 nanoparticles containing cleavable disulfide-bond linkers.  

Science.gov (United States)

The surface of superparamagnetic silica coated iron oxide (Fe3O4@SiO2) nanoparticles was functionalized with a disulfide bond linked N-hydroxysuccinimidyl (NHS) ester group in order to develop a method for labeling primary amines in peptides/proteins. The nanoparticle labeled proteins/peptides formed after NHS ester reaction with the primary amine groups were isolated using a magnet without any additional purification step. Nanoparticle moieties conjugated to peptides/proteins were then trimmed by cleavage at the disulfide linker with a reducing agent. The labeled peptides were analyzed by LC-MS/MS to determine their sequences and the sites of NHS ester labeling. This novel approach allowed characterization of lysine residues on the solvent accessible surface of native bovine serum albumin. Low cost, rapid magnetic separation, and specificity toward primary amine groups make NHS ester coated Fe3O4@SiO2 nanoparticles a potential labeling probe to study proteins on living cell surfaces. PMID:23909594

Patil, Ujwal S; Qu, Haiou; Caruntu, Daniela; O'Connor, Charles J; Sharma, Arjun; Cai, Yang; Tarr, Matthew A

2013-09-18

160

Developing Fe3O4 nanoparticles into an efficient multimodality imaging and therapeutic probe  

Science.gov (United States)

A rapid ligand-exchange method was developed to transfer high quality hydrophobic magnetite nanocrystals into water-soluble NPs by using protocatechuic acid as a ligand via homogenous reaction. After ligand exchange, the magnetite nanocrystals not only exhibited outstanding stability in water, but also maintained high crystallinity and saturation magnetization. Cell viability experiments demonstrated good biocompatibility of the NPs. For 12 nm magnetite nanoparticles (NPs), the small hydrodynamic size of 14 nm enabled a high T1 relaxivity of 17.8 mM-1 s-1 while high saturation magnetization of 77.8 emu g-1 enabled the NPs to exhibit a high T2 relaxivity of 220 mM-1 s-1 in MRI phantom experiments. In vivo MR imaging experiments further confirmed that the NPs were eminent T1 and T2 contrast agents. Moreover, the high quality NPs can be used as excellent magnetic heating agents under an alternating magnetic field. With all those features, including multimodality imaging and magnetic hyperthermia, the NPs can be used as single compound multifunctional agents for various biomedical applications, especially for cancer diagnosis and therapy.

Hao, Rui; Yu, Jing; Ge, Zigang; Zhao, Lingyun; Sheng, Fugeng; Xu, Lili; Li, Gongjie; Hou, Yanglong

2013-11-01

 
 
 
 
161

Humic acid coated Fe3O4 magnetic nanoparticles as highly efficient Fenton-like catalyst for complete mineralization of sulfathiazole  

International Nuclear Information System (INIS)

Humic acid coated Fe3O4 magnetic nanoparticles (Fe3O4/HA) were prepared for the removal of sulfathiazole from aqueous media. Fe3O4/HA exhibited high activity to produce hydroxyl (·OH) radicals through catalytic decomposition of H2O2. The degradation of sulfathiazole was strongly temperature-dependent and favored in acidic solution. The catalytic rate was increased with Fe3O4/HA dosage and H2O2 concentration. When 3 g L-1 of Fe3O4/HA and 0.39 M of H2O2 were introduced to the aqueous solution, most sulfathiazole was degraded within 1 h, and >90% of total organic carbon (TOC) were removed in the reaction period (6 h). The major final products were identified as environmentally friendly ions or inorganic molecules (SO42-, CO2, and N2). The corresponding degradation rate (k) of sulfathiazole and TOC was 0.034 and 0.0048 min-1, respectively. However, when 3 g L-1 of bare Fe3O4 were used as catalyst, only 54% of TOC was eliminated, and SO42- was not detected within 6 h. The corresponding degradation rate for sulfathiazole and TOC was 0.01 and 0.0016 min-1, respectively. The high catalytic ability of Fe3O4/HA may be caused by the electron transfer among the complexed Fe(II)-HA or Fe(III)-HA, leading to rapid regeneration of Fe(II) species and production of ·OH radicals.

2011-06-15

162

Antitumor efficacy of DMSA modified Fe3O4 magnetic nanoparticles combined with arsenic trioxide and adriamycin in Raji cells.  

Science.gov (United States)

The objective of the present study was to investigate the anticancer efficacy of dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4) magnetic nanoparticles (MNPs) combined with arsenic trioxide (As2O3) and doxorubicin (ADM) in non-Hodgkin's lymphoma (NHL) cell line (Raji cells). The growth inhibition rate of Raji cells was determined by MTT assay. Characteristics of DMSA-Fe3O4 MNPs and distribution of nanoparticles taken up by Raji cells were observed under a transmission electron microscopy (TEM). Further, apoptosis of cells and intracellular concentration of ADM were detected by flow cytometry (FCM). DAPI staining was used to view apoptotic cellular morphology. Subsequently, transcription and protein expression levels of bcl-2, NFKB, survivin, bax, p53 and caspase-3 were determined by reverse transciptase polymerase chain reaction (RT-PCR) and Western blotting analysis, respectively. The results of MTT assay indicated that the inhibition of Raji cells by the combined form of ADM and As2O3 was significantly higher than either ADM or As2O3 alone. However, ADM-As2O3 MNPs proved superior over all other groups. TEM observation revealed that the majority of MNPs were quasi-spherical with an average diameter of about 18 nm and the MNPs taken up by cells were located in the endosome vesicles of cytoplasm. The apoptotic rate and accumulation of intracellular ADM in ADM-As2O3 MNPs group were significantly higher than those in control, ADM, As2O3 and ADM+As2O3, groups. In addition, DAPI staining of Raji cells from ADM-As,O3 MNPs group clearly exhibited more morphological changes (severe structural alterations) than other groups. Moreover, transcription and protein expression of bcl-2, NFKB, survivin, bax, p53 and caspase-3 of Raji cells were regulated at the most remarkable extent in ADM-As2O3, MNPs group as compared with other groups. These findings suggest that the antitumor efficacy of the combination of novel ADM-As2O3, MNPs on Raji cells would be a promising strategy for lymphoma therapy. PMID:24738333

Cai, Xiaohui; Cai, Xiaohui; Wang, Chunling; Chen, Baoan; Hua, Weijun; Shen, Fei; Yu, Liang; He, Zhengmei; Shi, Yuye; Chen, Yue; Xia, Guohua; Bao, Wen; Zhang, Yu; Wang, Xuemei

2014-02-01

163

Inhibition of choriocarcinoma by Fe3O4-dextran-anti-ß-human chorionic gonadotropin nanoparticles containing antisense oligodeoxynucleotide of heparanase  

Directory of Open Access Journals (Sweden)

Full Text Available Liu Huining,1 Zhang Yi,1 Tang Dihong,2 Pan Yifeng,3 Xia Man,2 Yang Ting,2 Cai Jingting1,2 1Department of Obstetrics and Gynecology, Xiangya Hospital, 2Department of Gynecological Oncology, Hunan Provincial Tumor Hospital, 3National Hepatobiliary and Enteric Surgery Research Center, Central South University, Changsha, Hunan, People's Republic of China Objective: To observe the influence of Fe3O4-dextran-anti-ß-human chorionic gonadotropin (HCG carrying heparanase (Hpa antisense oligodeoxynucleotide (ASODN, via the invasion, proliferation, and Hpa expression of JEG-3 cell lines and inhibitory effect of transplanted choriocarcinoma tumor growth. Methods: The different abilities of invasion and proliferation between transfected JEG-3 and untransfected JEG-3 were measured by Matrigel invasion assay and 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay in vitro. The effect of Hpa ASODN transfection on the expression of Hpa mRNA and protein was measured by reverse-transcription polymerase chain reaction and Western blot. The transplanted choriocarcinoma tumors were taken out to calculate the inhibitory effect on tumor growth of Hpa ASODN. Results: In this study, we found that: (1 the invasive ability of JEG-3 cells was inhibited sufficiently (P < 0.05 after JEG-3 cells were transfected by Fe3O4-dextran-anti-?HCG carrying Hpa ASODN; (2 after JEG-3 cells were transfected by Fe3O4-dextran-anti-?HCG carrying Hpa ASODN at 48 and 72 hours, the proliferative ability of JEG-3 cells was inhibited sufficiently (P < 0.05; (3 the expression of Hpa mRNA and protein in JEG-3 cells was inhibited efficiently after JEG-3 cells were transfected by Fe3O4-dextran-anti-?HCG carrying Hpa ASODN (P < 0.05; and (4 Fe3O4-dextran-anti-?HCG carrying Hpa ASODN had an inhibitory effect on the transplanted choriocarcinoma tumor growth (P < 0.05 and was harmless on nude mice. Conclusion: Fe3O4-dextran-anti-?HCG carrying Hpa ASODN weakened the invasive and proliferative ability of choriocarcinoma, with a significant inhibitory effect on the transplanted choriocarcinoma tumor. Therefore, Fe3O4-dextran-anti-?HCG carrying Hpa ASODN is an effective gene therapy, and Fe3O4-dextran-anti-?HCG nanoparticles are a harmless and effective gene vector. Keywords: heparanase, antisense oligodeoxynucleotide, Fe3O4-dextran-anti-?HCG nanoparticles, choriocarcinoma, invasive ability

Huining L

2013-11-01

164

Preparation and Characterization of Fe3O4/CdTe Magnetic/Fluorescent Nanocomposites and their Applications in Immuno-labeling and Fluorescent Imaging of Cancer Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The synthesis of a new kind of magnetic, fluorescent multifunctional nanoparticles (~30 nm in diameter) was demonstrated, where multiple fluorescent CdTe quantum dots (QDs) are covalently linked to and assembled around individual silica-coated superparamagnetic Fe3O4 nanoparticles and active carboxylic groups are presented on the surface for easy bioconjugation with biomolecules. The Fe3O4 nanoparticles were firstly functionalized with thiol groups, followed by chemical conjugation with multi...

Sun, Pan; Zhang, Hongyan; Liu, Chang; Fang, Jin; Wang, Meng; Chen, Jing; Zhang, Jingpu; Mao, Chuanbin; Xu, Shukun

2010-01-01

165

Radical induced degradation of acetaminophen with Fe3O4 magnetic nanoparticles as heterogeneous activator of peroxymonosulfate.  

Science.gov (United States)

Magnetic nano-scaled particles Fe3O4 were studied for the activation of peroxymonosulfate (PMS) to generate active radicals for degradation of acetaminophen (APAP) in water. The Fe3O4 MNPs were found to effectively catalyze PMS for removal of APAP, and the reactions well followed a pseudo-first-order kinetics pattern (R(2)>0.95). Within 120min, approximately 75% of 10ppm APAP was accomplished by 0.2mM PMS in the presence of 0.8g/L Fe3O4 MNPs with little Fe(3+) leaching (<4?g/L). Higher Fe3O4 MNP dose, lower initial APAP concentration, neutral pH, and higher reaction temperature favored the APAP degradation. The production of sulfate radicals and hydroxyl radicals was validated through two ways: (1) indirectly from the scavenging tests with scavenging agents, tert-butyl alcohol (TBA) and ethanol (EtOH); (2) directly from the electron paramagnetic resonance (ESR) tests with 0.1M 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO). Plausible mechanisms on the radical generation from Fe3O4 MNP activation of PMS are proposed based on the results of radical identification tests and XPS analysis. It appeared that Fe(2+)Fe(3+) on the catalyst surface was responsible for the radical generation. The results demonstrated that Fe3O4 MNPs activated PMS is a promising technology for water pollution caused by contaminants such as pharmaceuticals. PMID:24929305

Tan, Chaoqun; Gao, Naiyun; Deng, Yang; Deng, Jing; Zhou, Shiqing; Li, Jun; Xin, Xiaoyan

2014-07-15

166

Significant improvement of critical current density in MgB2 doped with ferromagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Ferromagnetic Fe3O4-doped MgB2 bulks were first fabricated in this work by the hot pressing method. It was found that Fe3O4 does not react with Mg or B during the fabrication process. Peak Jc values of the 5 wt% Fe3O4-doped MgB2 are higher than 106 A cm-2 in the temperature range 5-30 K. Especially at 30 K, the peak Jc is 1.02 x 106 A cm-2 for the 5 wt% Fe3O4-doped MgB2, the highest values at 30 K found in the literature, and about seven times that of the 5 wt% SiC-doped MgB2 sample. The drop in Jc with increasing field for the Fe3O4-doped MgB2 is significantly slower than that of the SiC-doped MgB2 at 30 K. These results indicate that the Fe3O4-doped MgB2 is a potential superconductor to be used at temperatures greater than 25 K which is a critical temperature for large-scale practical applications.

2009-01-01

167

Magnetic Fe3O4-Based Sandwich-Type Biosensor Using Modified Gold Nanoparticles as Colorimetric Probes for the Detection of Dopamine  

Directory of Open Access Journals (Sweden)

Full Text Available In this work, we designed a visual biosensor for dopamine (DA detection using magnetic Fe3O4 particles and dithiobis(sulfosuccinimidylpropionate-modified gold nanoparticles (DTSSP-AuNPs as the recognition elements. Specifically, DA molecules were assembled onto the surface of DTSSP-AuNPs via the amine coupling reaction between the amino group of DA and activated carboxyl group of DTSSP. Accordingly, DA-anchored DTSSP-AuNPs were captured by Fe3O4 through the interaction of catechol and iron. In a magnetic field, the formed Fe3O4-DA-DTSSP-AuNPs conjugates were easily removed from the solution, leading to fading of the AuNPs suspension and decrease of the UV/Vis signal. As a result, a detection limit of 10 nM for DA was achieved. The theoretical simplicity and high selectivity demonstrated that the sandwich-type strategy based on Fe3O4 and AuNPs would lead to many colorimetric detection applications in clinical study by rationally designing the surface chemistry of AuNPs and Fe3O4.

Zhiyong Wang

2013-12-01

168

Preparation of Fe3O4 nanoparticle enclosure hydroxylated multi-walled carbon nanotubes for the determination of aconitines in human serum samples.  

Science.gov (United States)

A magnetic carbon nanomaterial for Fe(3)O(4) enclosure hydroxylated multi-walled carbon nanotubes (Fe(3)O(4)-EC-MWCNTs-OH) was prepared by the aggregating effect of Fe(3)O(4) nanoparticle on MWCNTs-OH, and combined with high-performance liquid chromatography (HPLC)/diode array detection (DAD) to determine the aconitines (aconitine, hypaconitine and mesaconitine) in human serum samples. Compared with other extraction modes investigated in experiment, Fe(3)O(4)-EC-MWCNTs-OH sorbents showed a good affinity to target analytes. Some important parameters that could influence extraction efficiency of aconitines, including the extraction mode, amounts of Fe(3)O(4)-EC-MWCNTs-OH, pH of sample solution, extraction time, desorption solvent and desorption time, were optimized. Under optimal conditions, the recoveries of spiked serum samples were between 98.0% and 103.0%; relative standard deviations (RSDs) ranged from 0.9% to 6.2%. The correlation coefficients varied from 0.9996 to 0.9998. The limits of detection ranged from 3.1 ng mL(-1) to 4.1 ng mL(-1) at a signal-to-noise ratio of 3. The experimental results showed that the proposed method was feasible for the analysis of aconitines in serum samples. PMID:22483209

Zhang, Hong-Fei; Shi, Yan-Ping

2012-04-29

169

Effect of magnetic Fe3O4 nanoparticles with 2-methoxyestradiol on the cell-cycle progression and apoptosis of myelodysplastic syndrome cells  

Directory of Open Access Journals (Sweden)

Full Text Available Guohua Xia1,2, Baoan Chen1,2, Jiahua Ding1,2, Chong Gao1,2, Huixia Lu1,2, Zeye Shao1,2, Feng Gao1,2, Xuemei Wang2,31Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China; 2Faculty of Oncology, Medical School, Southeast University, Nanjing, People’s Republic of China; 3National Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of ChinaAbstract: This study aims to evaluate the potential benefit of combination therapy of 2-methoxyestradiol (2ME and magnetic nanoparticles of Fe3O4 (MNPs- Fe3O4 on myelodysplastic syndrome (MDS SKM-1 cells and its underlying mechanisms. The effect of the unique properties of tetraheptylammonium-capped MNPs- Fe3O4 with 2ME on cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl-2,5- diphenyltetrazolium bromide assay. Cell-cycle distribution and apoptosis were assessed by flow cytometry. The expression of cell-cycle marker protein was measured by Western blotting. Growth inhibition rate of SKM-1 cells treated with the 2ME-loaded MNPs- Fe3O4 was enhanced when compared with 2ME alone. 2ME led to an increase of caspase-3 expression, followed by apoptosis, which was significantly increased when combined with an MNPs- Fe3O4 carrier. Moreover, the copolymer of 2ME with MNPs- Fe3O4 blocked a nearly two-fold increase in SKM-1 cells located in G2/M phase than in 2ME alone, which may be associated with an accompanying increase of p21 as well as a decrease in cyclin B1 and cdc2 expression, but there was no obvious difference between the MNPs- Fe3O4 and control group. These findings suggest that the unique properties of MNPs- Fe3O4 as a carrier for 2ME, a new anticancer agent currently in clinical trials, may be a logical strategy to enhance the therapeutic activity of MDS.Keywords: MDS, MNPs- Fe3O4, SKM-1 cell, cell cycle

Xia G

2011-09-01

170

Non-aqueous synthesis of water-dispersible Fe3O4-Ca3(PO4)2 core-shell nanoparticles  

Science.gov (United States)

The Fe3O4-Ca3(PO4)2 core-shell nanoparticles were prepared by one-pot non-aqueous nanoemulsion with the assistance of a biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO), integrating the magnetic properties of Fe3O4 and the bioactive functions of Ca3(PO4)2 into single entities. The Fe3O4 nanoparticles were pre-formed first by thermal reduction of Fe(acac)3 and then the Ca3(PO4)2 layer was coated by simultaneous deposition of Ca2 + and PO43 - . The characterization shows that the combination of the two materials into a core-shell nanostructure retains the magnetic properties and the Ca3(PO4)2 shell forms an hcp phase (a = 7.490 Å, c = 9.534 Å) on the Fe3O4 surface. The magnetic hysteresis curves of the nanoparticles were further elucidated by the Langevin equation, giving an estimation of the effective magnetic dimension of the nanoparticles and reflecting the enhanced susceptibility response as a result of the surface covering. Fourier transform infrared (FTIR) analysis provides the characteristic vibrations of Ca3(PO4)2 and the presence of the polymer surfactant on the nanoparticle surface. Moreover, the nanoparticles could be directly transferred to water and the aqueous dispersion-collection process of the nanoparticles was demonstrated for application readiness of such core-shell nanostructures in an aqueous medium. Thus, the construction of Fe3O4 and Ca3(PO4)2 in the core-shell nanostructure has conspicuously led to enhanced performance and multi-functionalities, offering various possible applications of the nanoparticles.

Liu, HongLing; Wu, JunHua; Min, Ji Hyun; Hou, Peng; Song, Ah-Young; Kim, Young Keun

2011-02-01

171

Non-aqueous synthesis of water-dispersible Fe3O4-Ca3(PO4)2 core-shell nanoparticles  

International Nuclear Information System (INIS)

The Fe3O4-Ca3(PO4)2 core-shell nanoparticles were prepared by one-pot non-aqueous nanoemulsion with the assistance of a biocompatible triblock copolymer, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO), integrating the magnetic properties of Fe3O4 and the bioactive functions of Ca3(PO4)2 into single entities. The Fe3O4 nanoparticles were pre-formed first by thermal reduction of Fe(acac)3 and then the Ca3(PO4)2 layer was coated by simultaneous deposition of Ca2+ and PO43-. The characterization shows that the combination of the two materials into a core-shell nanostructure retains the magnetic properties and the Ca3(PO4)2 shell forms an hcp phase (a = 7.490 A, c = 9.534 A) on the Fe3O4 surface. The magnetic hysteresis curves of the nanoparticles were further elucidated by the Langevin equation, giving an estimation of the effective magnetic dimension of the nanoparticles and reflecting the enhanced susceptibility response as a result of the surface covering. Fourier transform infrared (FTIR) analysis provides the characteristic vibrations of Ca3(PO4)2 and the presence of the polymer surfactant on the nanoparticle surface. Moreover, the nanoparticles could be directly transferred to water and the aqueous dispersion-collection process of the nanoparticles was demonstrated for application readiness of such core-shell nanostructures in an aqueous medium. Thus, the construction of Fe3O4 and Ca3(PO4)2 in the core-shell nanostructure has conspicuously led to enhanced performance and multi-functionalities, offering various possible applications of the nanoparticles.

2011-02-04

172

Magnetic Fe3O4-Based Sandwich-Type Biosensor Using Modified Gold Nanoparticles as Colorimetric Probes for the Detection of Dopamine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work, we designed a visual biosensor for dopamine (DA) detection using magnetic Fe3O4 particles and dithiobis(sulfosuccinimidylpropionate)-modified gold nanoparticles (DTSSP-AuNPs) as the recognition elements. Specifically, DA molecules were assembled onto the surface of DTSSP-AuNPs via the amine coupling reaction between the amino group of DA and activated carboxyl group of DTSSP. Accordingly, DA-anchored DTSSP-AuNPs were captured by Fe3O4 through the interaction of catechol and iron...

Zhiyong Wang; Yanyan Bai; Wenchao Wei; Ning Xia; Yuhui Du

2013-01-01

173

Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice  

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Baoan Chen1,* Jian Cheng1,* Yanan Wu1, Feng Gao1, Wenlin Xu2, et al 1Department of Hematology;2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, PR China *These authors have contributed equally to this workAbstract: In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4) combined ...

2009-01-01

174

Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4) combined with daunorubicin (DNR) in vivo. Two subclones of K562 and K562/A02 cells were inoculated subcutaneously into the back of athymic nude mice (1 × 107 cells/each) respectively to establish leukemia xenograft models. Drug-resistant and sensitive tumor-bearing nude mice ...

Chen, Baoan; Cheng, Jian; Wu, Yanan; Gao, Feng; Xu, Wenlin; Shen, Huilin; Ding, Jiahua; Gao, Chong; Sun, Qian; Sun, Xinchen; Cheng, Hongyan; Li, Guohong; Chen, Wenji; Chen, Ningna; Liu, Lijie

2009-01-01

175

Effect of magnetic nanoparticles of Fe3O4 and 5-bromotetrandrine on reversal of multidrug resistance in K562/A02 leukemic cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aims to evaluate the multidrug resistance (MDR) reversal activity by magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) and 5-bromotetrandrine (BrTet) MDR cell line K562/A02 solitarily or symphysially. The proliferation of K562 and K562/A02 cells and the cytotoxicity on peripheral blood mononuclear cells (PMBCs) were evaluated by MTT assay. Cellular accumulation of daunorubicin (DNR) was analyzed by flow cytometry. Real-time polymerase chain reaction and Western blotting analyses were pe...

Cheng, Jian; Wu, Weiwei; Chen, Bao-an; Gao, Feng; Xu, Wenlin; Gao, Chong; Ding, Jiahua; Sun, Yunyu; Song, Huihui; Bao, Wen; Sun, Xinchen; Xu, Cuirong; Chen, Wenji; Chen, Ningna; Liu, Lijie

2009-01-01

176

Functionalized magnetic iron oxide (Fe3O4) nanoparticles for capturing gram-positive and gram-negative bacteria.  

Science.gov (United States)

The development of nanotechnology in biology and medicine has raised the need for conjugation of nanoparticles (NPs) to biomolecules. In this study, magnetic and functionalized magnetic iron oxide nanoparticles were synthesized and used as affinity probes to capture Gram-positive/negative bacteria. The morphology and properties of the magnetic NPs were examined by transmission electron microscopy, Fourier transform infrared spectroscopy, and zeta potential measurements. Furthermore, this study investigated the interaction between functionalized magnetic nanoparticles and Gram positive/negative bacteria. The positively and negatively charged magnetic nanoparticles include functionalities of Fe3O4, SiO2, TiO2, ZrO2, poly ethyleneimine (PEI) and poly acrylic acid. Their capture efficiencies for bacteria were investigated based on factors such as zeta potential, concentration and pH value. PEI particles carry a positive charge over a range of pH values from 3 to 10, and the particles were found to be an excellent candidate for capturing bacteria over such pH range. Since the binding force is mainly electrostatic, the architecture and orientation of the functional groups on the NP surface are not critical. Finally the captured bacteria were analyzed using matrix-assisted laser desorption/ionization mass spectrometry. The minimum detection limit was 10(4) CFU/mL and the analysis time was reduced to be less than 1 hour. In addition, the detection limit could be reduced to an extremely low concentration of 50 CFU/mL when captured bacteria were cultivated. PMID:25016643

Reddy, P Muralidhar; Chang, Kai-Chih; Liu, Zhen-Jun; Chen, Cheng-Tung; Ho, Yen-Peng

2014-08-01

177

Room Temperature Synthesis of Magnetite (Fe3-?O4) Nanoparticles by a Simple Reverse Co-Precipitation Method  

International Nuclear Information System (INIS)

Magnetite (Fe3-?O4) nanoparticles with the size less than 30 nm have been synthesized by using a simple reverse co-precipitation method at room temperature. During the process, ferrous sulfate (FeSO4·7H2O) powder was used as an iron precursor, and ammonium hydroxide (NH4OH) as a precipitating agent. The experiment was carried out in ambient atmosphere without any surfactant added. In this method, the base solution for the precipitation process was adjusted to have a pH value suitable for the formation of the magnetite phase. The iron salt precursor was added into the solution during the synthesis by two different synthesis protocols. The phase, morphology and magnetic characteristic of differently synthesized magnetite particles were characterized by using an X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The morphologies of the particles were spherical or irregular in shape depending on the synthesis protocol used. Magnetic measurement shows that the particles are ferromagnetic at room temperature with relatively high saturation magnetization and low hysteresis. The saturation magnetization and magnetic hysteresis of the particles varied with preparation reaction conditions and the resulting oxidation state of the particles.

2011-10-29

178

Efficient purification of ginkgolic acids from Ginkgo biloba leaves by selective adsorption on Fe3O4 magnetic nanoparticles.  

Science.gov (United States)

Ginkgolic acids (GAs; anacardic acids; 6-alkylsalicylic acids) are both unwanted constituents in standardized Ginkgo biloba (Ginkgo) extracts and desirable constituents for pharmacological assays. Thus, for the quality control of Ginkgo extracts, the availability of pure GAs is important. In this investigation, inexpensive and easily prepared Fe3O4 magnetic nanoparticles (MNPs) in methanol were used to selectively adsorb GAs from crude petroleum ether extracts of Ginkgo leaves in the presence of various lipids including other alkylphenols (cardanols and cardols). The adsorption capacity of the MNPs is high, at 4-5% (w/w). The moiety responsible for the adsorption is the salicylic acid group, which binds strongly to Fe(III). Desorption with acidified methanol gave an extract with a GA content of 73%. This could be further separated by preparative HPLC on a C8 column. In total, eight different GAs were captured by MNPs. The MNP adsorption step can replace more traditional column chromatography and liquid-liquid extraction steps and is superior in terms of solvent consumption, selectivity, labor, and energy consumption. MNPs might become an efficient separation technique for selected high-value phytochemicals that contain a salicylic acid moiety. PMID:24484321

Li, Renkai; Shen, Yao; Zhang, Xiaojuan; Ma, Ming; Chen, Bo; van Beek, Teris A

2014-03-28

179

Study of the enhanced anticancer efficacy of gambogic acid on Capan-1 pancreatic cancer cells when mediated via magnetic Fe3O4 nanoparticles  

Directory of Open Access Journals (Sweden)

Full Text Available Cailian Wang1,*, Haijun Zhang1,*, Baoan Chen2, Haitao Yin1, Wenwen Wang11Department of Oncology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China; 2Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China *These authors contributed equally to this workBackground: Gambogic acid (GA, a potent anticancer agent, is limited in clinical administration due to its poor water solubility. The aim of this study was to explore a drug delivery system based on magnetic Fe3O4 nanoparticles (MNP- Fe3O4 conjugated with GA to increase water solubility of the drug and enhance its chemotherapeutic efficiency for pancreatic cancer.Methods: GA was conjugated with the MNP- Fe3O4 colloidal suspension by mechanical absorption polymerization to construct GA-loaded MNP- Fe3O4, which acted as a drug delivery system.Results: Combination therapy with GA and MNP- Fe3O4 induced remarkable improvement in anticancer activity, which was demonstrated by optical microscopic observations, MTT assay, and nuclear DAPI staining. Furthermore, the possible signaling pathway was explored by Western blot. In Capan-1 pancreatic cancer cells, our observations demonstrated that this strategy could enhance potential anticancer efficiency by inducing apoptosis. The mechanisms of the synergistic effect may be due to reducing protein expression of Bcl-2 and enhancing that of Bax, caspase 9, and caspase 3.Conclusion: These findings demonstrate that a combination of GA and MNPs- Fe3O4 represents a promising approach to the treatment of pancreatic cancer.Keywords: gambogic acid, pancreatic cancer, magnetic nanoparticles, drug delivery system, apoptosis

Wang C

2011-09-01

180

Synthesis and photocatalytic property of Fe3O4@TiO2 core/shell nanoparticles supported by reduced graphene oxide sheets  

International Nuclear Information System (INIS)

Highlights: •Fe3O4@TiO2 nanoparticles loaded on graphene sheets are synthesized for the first time. •This ternary structure can induce photo-degradation of methyl orange. •The interfacial structure between TiO2 and Fe3O4 is stable at 450 °C. •Fe3O4@TiO2/graphene as ternary photocatalyst can be retrieved by magnetic field. -- Abstract: A ternary nanocomposite of Fe3O4@TiO2/reduced graphene oxide (FTR) was prepared successfully by a facile route in this work. Fe3O4@TiO2 core/shell nanospheres were loaded on the surface of reduced graphene oxide (RGO), making the ternary nanocomposite possessed enhanced charge separation efficiency in combined with the supporting media of RGO. The morphology of the ternary nanocomposite was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic degradation efficiency on methyl orange of the FTR nanocomposite was investigated. The photocatalytic degradation efficiency of ternary composite was about three times than that of pure TiO2. The result show that the photocatalytic efficiency of 25 mg FTR can reach 83.8% in 50 min, In addition to the high efficiency of the degradation property, the ternary composite can be easily recycled by normal magnet due to the magnetite core. It is suggested that the FTR ternary composite of Fe3O4@TiO2/reduced graphene oxide can be an efficient multifunctional photocatalyst for the degradation of hazardous compounds in waste water

2013-11-25

 
 
 
 
181

Preparation, characterization of Fe3O4 at TiO2 magnetic nanoparticles and their application for immunoassay of biomarker of exposure to organophosphorus pesticides  

Energy Technology Data Exchange (ETDEWEB)

Novel Fe3O4 at TiO2 magnetic nanoparticles were prepared and developed for a new nanoparticle-based immunosensor for electrochemical quantification of organophosphorylated butyrylcholinesterase (BChE) in plasma, a specific biomarker of exposure to organophosphorus (OP) agents. The Fe3O4 at TiO2 nanoparticles were synthesized by hydrolysis of tetrabutyltitanate on the surface of Fe3O4 magnetic nanospheres, and characterized by attenuated total reflection Fourier-transform infrared spectra, transmission electron microscope and X-ray diffraction. The functional Fe3O4 at TiO2 nanoparticles were performed as capture antibody to selectively enrich phosphorylated moiety instead of phosphoserine antibody in the traditional sandwich immunoassays. The secondary recognition was served by quantum dots (QDs)-tagged anti-BChE antibody (QDs-anti-BChE). With the help of a magnet, the resulting sandwich-like complex, Fe3O4 at TiO2/OP-BChE/QDs-anti-BChE, was easily isolated from sample solutions and the released cadmium ions were detected on a disposable screen-printed electrode (SPE). The binding affinities were investigated by both surface plasmon resonance (SPR) and square wave voltammetry (SWV). This method not only avoids the drawback of unavailability of commercial OP-specific antibody but also amplifies detection signal by QDs-tags together with easy separation of samples by magnetic forces. The proposed immunosensor yields a linear response over a broad OP-BChE concentrations range from 0.02 to 10 nM, with detection limit of 0.01 nM. Moreover, the disposable nanoparticle-based immunosensor has been validated with human plasma samples. It offers a new method for rapid, sensitive, selective and inexpensive screening/evaluating exposure to OP pesticides.

Zhang, Xiao; Wang, Hongbo; Yang, Chunming; Du, Dan; Lin, Yuehe

2013-03-15

182

Preparation, characterization of Fe3O4 at TiO2 magnetic nanoparticles and their application for immunoassay of biomarker of exposure to organophosphorus pesticides.  

Science.gov (United States)

Novel Fe(3)O(4) at TiO(2) magnetic nanoparticles were prepared and developed for a new nanoparticle-based immunosensor for electrochemical quantification of organophosphorylated butyrylcholinesterase (BChE) in plasma, a specific biomarker of exposure to organophosphorus (OP) agents. The Fe(3)O(4) at TiO(2) nanoparticles were synthesized by hydrolysis of tetrabutyltitanate on the surface of Fe(3)O(4) magnetic nanospheres, and characterized by attenuated total reflection Fourier-transform infrared spectra, transmission electron microscope and X-ray diffraction. The functional Fe(3)O(4) at TiO(2) nanoparticles were performed as capture antibody to selectively enrich phosphorylated moiety instead of phosphoserine antibody in the traditional sandwich immunoassays. The secondary recognition was performed by quantum dots (QDs)-tagged anti-BChE antibody (QDs-anti-BChE). With the help of a magnet, the resulting sandwich-like complex, Fe(3)O(4) at TiO(2)/OP-BChE/QDs-anti-BChE, was easily isolated from sample solutions and the released cadmium ions were detected on a disposable screen-printed electrode (SPE). The binding affinities were investigated by both surface plasmon resonance (SPR) and square wave voltammetry (SWV). This method not only avoids the drawback of unavailability of commercial OP-specific antibody but also amplifies detection signal by QDs-tags together with easy separation of samples by magnetic forces. The proposed immunosensor yields a linear response over a broad OP-BChE concentrations range from 0.02 to 10 nM, with detection limit of 0.01 nM. Moreover, the disposable nanoparticle-based immunosensor has been validated with human plasma samples. It offers a new method for rapid, sensitive, selective and inexpensive screening/evaluating exposure to OP pesticides and nerve agents. PMID:23122753

Zhang, Xiao; Wang, Hongbo; Yang, Chunming; Du, Dan; Lin, Yuehe

2013-03-15

183

Immobilization of cyclodextrin glucanotransferase on aminopropyl-functionalized silica-coated superparamagnetic nanoparticles  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Background: Cyclodextrin glycosyltransferase (CGTase) from Amphibacillus sp. NPST-10 was successfully covalently immobilized on aminopropyl-functionalized silica coated superparamagnetic nanoparticles; and the properties of immobilized enzyme were investigated. The synthesis process included prepari [...] ng of core magnetic magnetite (Fe3O4) nanoparticles using solvothermal synthesis; followed by coating of Fe3O4 nanoparticles with dense amino-functionalized silica (NH2-SiO2) layer using in situ functionalization method. The structure of synthesized Fe3O4@NH2-SiO2 nanoparticles was characterized using TEM, XRD, and FT-IR analysis. Fe3O4@NH2-SiO2 nanoparticles were further activated by gluteraaldehyde as bifunctional cross linker, and the activated nanoparticles were used for CGTase immobilization by covalent attachment. Results: Magnetite nanoparticles was successfully synthesized and coated with and amino functionalized silica layer (Fe3O4/NH2-SiO2), with particle size of 50-70 nm. The silica coated magnetite nanoparticles showed with saturation magnetization of 65 emug-1, and can be quickly recovered from the bulk solution using an external magnet within 10 sec. The activated support was effective for CGTase immobilization, which was confirmed by comparison of FT-IR spectra of free and immobilized enzyme. The applied approach for support preparation, activation, and optimization of immobilization conditions, led to high yields of CGTase immobilization (92.3%), activity recovery (73%), and loading efficiency (95.2%); which is one of the highest so far reported for CGTase. Immobilized enzyme showed shift in the optimal temperature from 50 to 55ºC, and significant enhancement in the thermal stability compared with free enzyme. The optimum pH for enzyme activity was pH 8 and pH 7.5 for free and immobilized CGTase, respectively, with slight improvement of pH stability of immobilized enzyme. Furthermore, kinetic studies revealed that immobilized CGTase had higher affinity toward substrate; with k m values of 1.18 ± 0.05 mg/ml and 1.75 ± 0.07 mg/ml for immobilized and free CGTase, respectively. Immobilized CGTase retained 87% and 67 of its initial activity after 5 and 10 repeated batches reaction, indicating that immobilized CGTase on Fe3O4/NH2-SiO2 had good durability and magnetic recovery. Conclusion: The improvement in kinetic and stability parameters of immobilized CGTase makes the proposed method a suitable candidate for industrial applications of CGTase. To best of our knowledge, this is the first report about CGTase immobilization on silica coated magnetite nanoparticles.

Ibrahim, Abdelnasser S.S.; Al-Salamah, Ali A; El-Toni, Ahmed Mohamed; El-Tayeb, Mohamed A; Elbadawi, Yahya B.

184

Self-assembly and graft polymerization route to Monodispersed Fe3O4@SiO2--polyaniline core-shell composite nanoparticles: physical properties.  

Science.gov (United States)

This study describes the synthesis of monodispersed core-shell composites of silica-modified magnetic nanoparticles and conducting polyaniline by self-assembly and graft polymerization. Magnetic ferrite nanoparticles (Fe3O4) were prepared by coprecipitation of Fe+2 and Fe+3 ions in alkaline solution, and then silananized. The silanation of magnetic particles (Fe3O4@SiO2) was carried out using 3-bromopropyltrichlorosilane (BPTS) as the coupling agent. FT-IR spectra indicated the presence of Fe--O--Si chemical bonds in Fe3O4@SiO2. Core-shell type nanocomposites (Fe3O4@SiO2/PANI) were prepared by grafting polyaniline (PANI) on the surface of silanized magnetic particles through surface initiated in-situ chemical oxidative graft polymerization. The nanocomposites were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), Fourier transform infrared (FTIR) spectra, UV-visible spectroscopy, photoluminescence (PL) spectra, electrical conductivity and magnetic characteristics. HRTEM images of the nanocomposites revealed that the silica-modified magnetic particles made up the core while PANI made up the shell. The XPS spectrum revealed the presence of silica in the composites, and the XRD results showed that the composites were more crystalline than pure PANI. PL spectra show that composites exhibit photoluminescent property. Conductivity of the composites (6.2 to 9.4 x 10(-2) S/cm) was higher than that of pristine PANI (3.7 x 10(-3) S/cm). The nanocomposites exhibited superparamagnetism. Formation mechanism of the core-shell structured nanocomposites and the effect of modified magnetic nanoparticles on the electro-magnetic properties of the Fe3O4@SiO2/PANI nanocomposites are also investigated. This method provides a new strategy for the generation of multi-functional nanocomposites that composed of other conducting polymers and metal nanoparticles. PMID:19198281

Reddy, Kakarla Raghava; Lee, Kwang-Pill; Kim, Ju Young; Lee, Youngil

2008-11-01

185

Simple and efficient deposition of Pd nanoparticles on Fe3O4 hollow nanospheres: A new catalytic system for methanol oxidation in alkaline media  

International Nuclear Information System (INIS)

An efficient, low-cost and general strategy is developed to deposit well-dispersed Pd nanoparticles on Fe3O4 hollow nanospheres. In this route, Fe3O4 hollow nanospheres pretreated with dilute HCl solution were firstly employed as supports and simple chemical reduction was then introduced. The morphology, structure and elemental composition of the as-obtained samples were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), nitrogen sorption and elemental analysis. Electrodes coated with the Pd/Fe3O4 were studied for the oxidation of methanol in 0.1 M NaOH in half cells. The results show highly dispersed Pd nanoparticles are evenly immobilized on the surface of Fe3O4 hollow nanospheres. The cyclic voltammetry tests reveal this novel composite possesses excellent electrocatalytic activity and long-term stability for methanol oxidation in alkaline media.

2010-09-15

186

Reversal in multidrug resistance by magnetic nanoparticle of Fe3O4 loaded with adriamycin and tetrandrine in K562/A02 leukemic cells  

Directory of Open Access Journals (Sweden)

Full Text Available Baoan Chen1,5, Qian Sun1,5, Xuemei Wang2, Feng Gao1, Yongyuan Dai1, Yan Yin1, Jiahua Ding1, Chong Gao1, Jian Cheng1, Jingyuan Li2, Xinchen Sun1, Ningna Chen1, Wenlin Xu3, Huiling Shen3, Delong Liu41Department of Hematology, Zhongda Hospital, Southeast University, Nanjing, China; 2State Key Lab of Bioelectronics(Chien-Shiung Wu Laboratory, Southeast University, Nanjing 210096, China; 3Department of Hematology, The First People’s Hospital of Zhenjiang, Zhenjiang, China; 4Westchester Medical Center, New York Medical College, NY, USA; 5These authors have contributed equally to this work.Abstract: Drug resistance is a primary hindrance for efficiency of chemotherapy. To investigate whether Fe3O4-magnetic nanoparticles (Fe3O4-MNPs loaded with adriamycin (ADM and tetrandrine (Tet would play a synergetic reverse role in multidrug resistant cell, we prepared the drug-loaded nanoparticles by mechanical absorption polymerization to act with K562 and one of its resistant cell line K562/A02. The survival of cells which were cultured with these conjugates for 48 h was observed by MTT assay. Using cells under the same condition described before, we took use of fluorescence microscope to measure fluorescence intensity of intracellular ADM at an excitation wavelength of 488 nm. P-glycoprotein (P-gp was analyzed with flow cytometer. The expression of mdr1 mRNA was measured by RT-PCR. The results showed that the growth inhibition efficacy of both the two cells increased with augmenting concentrations of Fe3O4-MNPs which were loaded with drugs. No linear correlation was found between fluorescence intensity of intracellular adriamycin and augmenting concentration of Fe3O4-MNPs. Tet could downregulate the level of mdr-1 gene and decrease the expression of P-gp. Furthermore, Tet polymerized with Fe3O4-MNPs reinforced this downregulation, causing a 100-fold more decrease in mdr1 mRNA level, but did not reduce total P-gp content. Our results suggest that Fe3O4-MNPs loaded with ADM or Tet can enhance the effective accumulation of the drugs in K562/A02. We propose that Fe3O4-MNPs loaded with ADM and Tet probably have synergetic effect on reversal in multidrug resistance.Keywords: magnetic nanoparticles, tetrandrine, adriamycin, multidrug resistance reversal, leukemia K562/A02

Baoan Chen

2008-06-01

187

Biodesel Production from Pseudomonas Fluorescens Lp1 Lipase Immobilized on Amino-silane Modified Super Paramagnetic Fe3O4 Nanoparticles  

Science.gov (United States)

An extracellular lipase from Pseudomonas fluorescens Lp1 isolated from oil contaminated soil was immobilized onto amino silane modified superparamagnetic Fe3O4 nanoparticles. The magnetic nanoparticles, magnetite was synthesized chemically by co-precipitation and characterized by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FT-IR) and Powder X-ray diffraction studies (XRD). The structure of the synthesized magnetic nanoparticles was uniform, spherical and the size was determined around 31 nm by powder XRD. The biodiesel production mixture was prepared by addition of waste cooking oil, lipase immobilized magnetite and methanol. The transesterified products were analyzed by Gas Liquid chromatography-Mass spectroscopy (GC-MS). The methyl esters such as Oxiraneundecanoic acid, 3-pentyl-methyl ester, Hexadecanoic acid, methyl ester and 10-Octadecenoic acid, methyl ester were obtained. The study experimentally proved the use of amino silane modified superparamagnetic Fe3O4 nanoparticles in biodiesel production from waste cooking oil.

Kanimozhi, S.; Perinbam, K.

2013-04-01

188

Biodesel Production from Pseudomonas Fluorescens Lp1 Lipase Immobilized on Amino-silane Modified Super Paramagnetic Fe3O4 Nanoparticles  

International Nuclear Information System (INIS)

An extracellular lipase from Pseudomonas fluorescens Lp1 isolated from oil contaminated soil was immobilized onto amino silane modified superparamagnetic Fe3O4 nanoparticles. The magnetic nanoparticles, magnetite was synthesized chemically by co-precipitation and characterized by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FT-IR) and Powder X-ray diffraction studies (XRD). The structure of the synthesized magnetic nanoparticles was uniform, spherical and the size was determined around 31 nm by powder XRD. The biodiesel production mixture was prepared by addition of waste cooking oil, lipase immobilized magnetite and methanol. The transesterified products were analyzed by Gas Liquid chromatography-Mass spectroscopy (GC-MS). The methyl esters such as Oxiraneundecanoic acid, 3-pentyl-methyl ester, Hexadecanoic acid, methyl ester and 10-Octadecenoic acid, methyl ester were obtained. The study experimentally proved the use of amino silane modified superparamagnetic Fe3O4 nanoparticles in biodiesel production from waste cooking oil.

2013-04-15

189

The effect of surface charge of functionalized Fe3O4 nanoparticles on protein adsorption and cell uptake.  

Science.gov (United States)

Nanoparticles engineered for biomedical applications are meant to be in contact with protein-rich physiological fluids. These proteins are usually adsorbed onto the nanoparticle's surface, forming a swaddling layer that has been described as a 'protein corona', the nature of which is expected to influence not only the physicochemical properties of the particles but also the internalization into a given cell type. We have investigated the process of protein adsorption onto different magnetic nanoparticles (MNPs) when immersed in cell culture medium, and how these changes affect the cellular uptake. The role of the MNPs surface charge has been assessed by synthesizing two colloids with the same hydrodynamic size and opposite surface charge: magnetite (Fe3O4) cores of 25-30 nm were in situ functionalized with (a) positive polyethyleneimine (PEI-MNPs) and (b) negative poly(acrylic acid) (PAA-MNPs). After few minutes of incubation in cell culture medium the wrapping of the MNPs by protein adsorption resulted in a 5-fold increase of the hydrodynamic size. After 24 h of incubation large MNP-protein aggregates with hydrodynamic sizes of ?1500 nm (PAA-MNPs) and ?3000 nm (PEI-MNPs) were observed, each one containing an estimated number of magnetic cores between 450 and 1000. These results are consistent with the formation of large protein-MNPs aggregate units having a 'plum pudding' structure of MNPs embedded into a protein network that results in a negative surface charge, irrespective of the MNP-core charge. In spite of the similar negative ?-potential for both MNPs within cell culture, we demonstrated that PEI-MNPs are incorporated in much larger amounts than the PAA-MNPs units. Quantitative analysis showed that SH-SY5Y cells can incorporate 100% of the added PEI-MNPs up to ?100 pg/cell, whereas for PAA-MNPs the uptake was less than 50%. The final cellular distribution showed also notable differences regarding partial attachment to the cell membrane. These results highlight the need to characterize the final properties of MNPs after protein adsorption in biological media, and demonstrate the impact of these properties on the internalization mechanisms in neural cells. PMID:24816288

Calatayud, M Pilar; Sanz, Beatriz; Raffa, Vittoria; Riggio, Cristina; Ibarra, M Ricardo; Goya, Gerardo F

2014-08-01

190

Preparation of Fe(3)O(4)@C@CNC multifunctional magnetic core/shell nanoparticles and their application in a signal-type flow-injection photoluminescence immunosensor.  

Science.gov (United States)

We describe here the preparation of carbon-coated Fe3O4 magnetic nanoparticles that were further fabricated into multifunctional core/shell nanoparticles (Fe3O4@C@CNCs) through a layer-by-layer self-assembly process of carbon nanocrystals (CNCs). The nanoparticles were applied in a photoluminescence (PL) immunosensor to detect the carcinoembryonic antigen (CEA), and CEA primary antibody was immobilized onto the surface of the nanoparticles. In addition, CEA secondary antibody and glucose oxidase were covalently bonded to silica nanoparticles. After stepwise immunoreactions, the immunoreagent was injected into the PL cell using a flow-injection PL system. When glucose was injected, hydrogen peroxide was obtained because of glucose oxidase catalysis and quenched the PL of the Fe3O4@C@CNC nanoparticles. The here proposed PL immunosensor allowed us to determine CEA concentrations in the 0.005–50 ng·mL-1 concentration range, with a detection limit of 1.8 pg·mL-1. PMID:24121430

Chu, Chengchao; Li, Meng; Li, Long; Ge, Shenguang; Ge, Lei; Yu, Jinghua; Yan, Mei; Song, Xianrang

2013-11-01

191

Fe3O4 nanoparticles prepared by the seeded-growth route for hyperthermia: electron magnetic resonance as a key tool to evaluate size distribution in magnetic nanoparticles  

Science.gov (United States)

Monodispersed Fe3O4 nanoparticles have been synthesized by a thermal decomposition method based on the seeded-growth technique, achieving size tunable nanoparticles with high crystallinity and high saturation magnetization. EMR spectroscopy becomes a very efficient complementary tool to determine the fine details of size distributions of MNPs and even to estimate directly the size in a system composed of a given type of magnetic nanoparticles. The size and size dispersity affect directly the efficiency of MNPs for hyperthermia and EMR provides a direct evaluation of these characteristics almost exactly in the same preparation and with the same concentration as used in hyperthermia experiments. The correlation observed between the Specific Absorption Rate (SAR) and the effective gyromagnetic factor (geff) is extremely remarkable and renders a way to assess directly the heating capacity of a MNP system.Monodispersed Fe3O4 nanoparticles have been synthesized by a thermal decomposition method based on the seeded-growth technique, achieving size tunable nanoparticles with high crystallinity and high saturation magnetization. EMR spectroscopy becomes a very efficient complementary tool to determine the fine details of size distributions of MNPs and even to estimate directly the size in a system composed of a given type of magnetic nanoparticles. The size and size dispersity affect directly the efficiency of MNPs for hyperthermia and EMR provides a direct evaluation of these characteristics almost exactly in the same preparation and with the same concentration as used in hyperthermia experiments. The correlation observed between the Specific Absorption Rate (SAR) and the effective gyromagnetic factor (geff) is extremely remarkable and renders a way to assess directly the heating capacity of a MNP system. Electronic supplementary information (ESI) available: Synthetic parameters of Fe3O4 nanoparticles obtained by the seeded growth method. Diffractograms of samples A-F. Deconvolution from the (311) diffraction peak of samples A-F. FTIR spectra of pure oleic acid and Fe3O4 nanoparticles coated with oleic acid. ZFC-FC curves of samples A-E in powder form. Hysteresis loops of powder samples. Non-Interacting Superparamagnetic (SPM) model. Fit of M(H) curves at room temperature. Calculation of SAR as a function of particle diameter. SAR values of sample E before and after the washing process. See DOI: 10.1039/c4nr00646a

Castellanos-Rubio, Idoia; Insausti, Maite; Garaio, Eneko; Gil de Muro, Izaskun; Plazaola, Fernando; Rojo, Teófilo; Lezama, Luis

2014-06-01

192

Orbital and spin moments of 5 to 11 nm Fe3O4 nanoparticles measured via x-ray magnetic circular dichroism  

Science.gov (United States)

The orbital and spin contributions to the magnetic moment of Fe in Fe3O4 nanoparticles were measured using X-ray magnetic circular dichroism (XMCD). Nanoparticles of different sizes, ranging from 5 to 11 nm, were fabricated via organic methods and their magnetic behavior was characterized by vibrating sample magnetometry (VSM). An XMCD signal was measured for three different samples at 300 K and 80 K. The extracted values for the orbital and spin contributions to the magnetic moment showed a quenching of the orbital moment and a large spin moment. The calculated spin moments appear somewhat reduced compared to the value expected for bulk Fe3O4. The spin moments measured at 80 K are larger than at 300 K for all the samples, revealing significant thermal fluctuations effects in the nanoparticle assemblies. The measured spin moment is reduced for the smallest nanoparticles, suggesting that the magnetic properties of Fe3O4 nanoparticles could be altered when their size reaches a few nanometers.

Cai, Y. P.; Chesnel, K.; Trevino, M.; Westover, A.; Harrison, R. G.; Hancock, J. M.; Turley, S.; Scherz, A.; Reid, A.; Wu, B.; Graves, C.; Wang, T.; Liu, T.; Dürr, H.

2014-05-01

193

Synthesis and characterization of a pH-sensitive conjugate of isoniazid with Fe3O4@SiO2 magnetic nanoparticles.  

Science.gov (United States)

The Letter describes the preparation and characterization of a conjugate of isoniazid (INH) with magnetic nanoparticles Fe3O4@SiO2 115±60 nm in size. The INH molecules were attached to the surface of nanoparticles by a covalent pH-sensitive amidine bond. The conjugate was characterized by X-ray diffraction, SEM, dynamic light scattering, IR spectroscopy and microanalysis. The conjugate released isoniazid under in vitro conditions (pH=4; 37 °C; t1/2?115 s). In addition, the cytotoxicity of the Fe3O4@SiO2-INH conjugate was evaluated in SK-BR-3 cells using the xCELLigence system. PMID:23809850

Sedlák, Miloš; Bhosale, Dattatry Shivajirao; Beneš, Ludvík; Palar?ík, Ji?í; Kalendová, Andrea; Královec, Karel; Imramovský, Aleš

2013-08-15

194

Investigation of magnetic field enriched surface enhanced resonance Raman scattering performance using Fe3O4@Ag nanoparticles for malaria diagnosis  

Science.gov (United States)

Recently, we have demonstrated the magnetic field-enriched surface-enhanced resonance Raman spectroscopy (SERRS) of ?-hematin by using nanoparticles with iron oxide core and silver shell (Fe3O4@Ag) for the potential application in the early malaria diagnosis. In this study, we investigate the dependence of the magnetic field-enriched SERRS performance of ?-hematin on the different core and shell sizes of the Fe3O4@Ag nanoparticles. We note that the core and shell parameters are critical in the realization of the optimal magnetic field-enrich SERRS ?-hematin signal. These results are consistent with our simulations that will guide the optimization of the magnetic SERRS performance for the potential early diagnosis in the malaria disease.

Yuen, Clement; Liu, Quan

2014-03-01

195

Characteristics of magnetic labeling on liver tumors with anti-alpha-fetoprotein-mediated Fe3O4 magnetic nanoparticles  

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Full Text Available Kai-Wen Huang,1 Jen-Jie Chieh,2 Herng-Er Horng,2 Chin-Yih Hong,3 Hong-Chang Yang41Department of Surgery and Hepatitis Research Center, National Taiwan University Hospital, Taipei, 2Institute of Electro-optical Science and Technology, National Taiwan Normal University, Taipei, 3Graduate Institute of Biomedical Engineering, National Chung Hsing University, Taichung, 4Department of Physics, National Taiwan University, Taipei, TaiwanAbstract: For preoperative and intraoperative detection of tumor distribution, numerous multimodal contrast agents, such as magnetic nanoparticles (MNPs with several examination indicators, are currently in development. However, complex materials, configuration, and cost are required for multimodal contrast agents, accompanied by a high possibility of toxicity and low popularity in clinics. Nevertheless, the magnetic labeling of MNPs using bioprobes should be feasible not only in preoperative magnetic resonance imaging (MRI, but also in intraoperative examination based on other magnetic properties. In this study, anti-alpha-fetoprotein (AFP-mediated Fe3O4 MNPs, injected into mice with liver tumors, were used to examine the characteristics of magnetic labeling. Using MRI and scanning superconducting-quantum-interference-device biosusceptometry (SSB, based on alternating current (AC susceptibility, the magnetic labeling occurred significantly on the first day post-injection of anti-AFP magnetic fluid (MF, and then decreased over time. However, for both MF without antibodies and an anti-carcinoembryonic antigen MF, no magnetic labeling occured on the first day of their respective post-injection. The favorable agreement indicates that magnetic labeling possesses two magnetic characteristics: distortion of the imaging field and AC susceptibility. In addition, the results of the biopsy tests, anti-AFP staining, and Prussian blue staining show the same dynamics as those of magnetic methodologies and prove that bound MNPs on tumor tissue are rotatable by an AC magnetic field to express AC susceptibility. Therefore, with the simple configuration of antibody-mediated MNPs, magnetic labeling is also feasible for intraoperative examinations using SSB with high mobility and sensitivity.Keywords: alpha-fetoprotein, magnetic resonance imaging, scanning SQUID biosusceptometry

Huang KW

2012-06-01

196

Fe3o4 nanoparticles: A highly efficient and easily reusable catalyst for the one-pot synthesis of xanthene derivatives under solvent-free conditions  

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Magnetically separable Fe3O4 nanoparticles supply environmentally friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene and 1,8-dioxo-octahydro-xanthene derivatives. These compounds were obtained in high yields and short reaction times by the reaction of dimedone and 2-naphthol with various aromatic aldehydes under solvent-free conditions. The catalyst coluld be easily recovered using an external magnet and reused for six cycles with almost consistent activity.

Ghasemzadeh Ali Mohammad; Safaei-Ghomi Javad; Zahedi Safura

2013-01-01

197

Fe3o4 nanoparticles: A highly efficient and easily reusable catalyst for the one-pot synthesis of xanthene derivatives under solvent-free conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Magnetically separable Fe3O4 nanoparticles supply environmentally friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene and 1,8-dioxo-octahydro-xanthene derivatives. These compounds were obtained in high yields and short reaction times by the reaction of dimedone and 2-naphthol with various aromatic aldehydes under solvent-free conditions. The catalyst coluld be easily recovered using an external magnet and reused for six cycles with almost consistent activity.

Ghasemzadeh Ali Mohammad

2013-01-01

198

Superparamagnetic Core-Shell-Type Fe3O4/Ru Nanoparticles as Catalysts for the Selective Hydrogenation of an Unconstrained ?,?-Unsaturated Ketone  

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Superparamagnetic core-shell-type Fe3O4/Ru nanoparticles (particle size ca. 15 nm) synthesized by co-precipitation, adsorption and reduction methods were found to selectively hydrogenate the carbon-oxygen double bond in trans-4-phenyl-3-penten-2-one (conversion 100?%, selectivity > 90?%) with a catalytic turnover of 900 under mild reaction conditions (30 °C, 15 bar H2). The finely dispersed catalyst can be separated from the reaction mixture by using an e...

2012-01-01

199

Magnetic Fe3O4@TiO2 Nanoparticles-based Test Strip Immunosensing Device for Rapid Detection of Phosphorylated Butyrylcholinesterase  

Energy Technology Data Exchange (ETDEWEB)

An integrated magnetic nanoparticles-based test-strip immunosensing device was developed for rapid and sensitive quantification of phosphorylated butyrylcholinesterase (BChE), the biomarker of exposure to organophosphous pesticides (OP), in human plasma. In order to overcome the difficulty in scarce availability of OP-specific antibody, here magnetic Fe3O4@TiO2 nanoparticles were used and adsorbed on the test strip through a small magnet inserted in the device to capture target OP-BChE through selective binding between TiO2 and OP moiety. Further recognition was completed by horseradish peroxidase (HRP) and anti-BChE antibody (Ab) co-immobilized gold nanoparticles (GNPs). Their strong affinities among Fe3O4@TiO2, OP-BChE and HRP/Ab-GNPs were characterized by quartz crystal microbalance (QCM), surface plasmon resonance (SPR) and square wave voltammetry (SWV) measurements. After cutting off from test strip, the resulted immunocomplex (HRP/Ab-GNPs/OP-BChE/Fe3O4@TiO2) was measured by SWV using a screen printed electrode under the test zone. Greatly enhanced sensitivity was achieved by introduction of GNPs to link enzyme and antibody at high ratio, which amplifies electrocatalytic signal significantly. Moreover, the use of test strip for fast immunoreactions reduces analytical time remarkably. Coupling with a portable electrochemical detector, the integrated device with advanced nanotechnology displays great promise for sensitive, rapid and in-filed on-site evaluation of OP poisoning.

Ge, Xiaoxiao; Zhang, Weiying; Lin, Yuehe; Du, Dan

2013-12-15

200

Synthesis of sulfonic acid-functionalized Fe3O4@C nanoparticles as magnetically recyclable solid acid catalysts for acetalization reaction.  

Science.gov (United States)

The Fe3O4@C core-shell magnetic nanoparticles with an average size of about 190 nm were synthesized via a one-pot solvothermal process using ferrocene as a single reactant. The sulfonic acid-functionalized Fe3O4@C magnetic nanoparticles were obtained by grafting the sulfonic groups on the surface of Fe3O4@C nanoparticles to produce magnetically recyclable solid acid catalysts. The as-prepared products were characterized by X-ray diffraction and transmission electron microscopy. The catalytic performance of the as-prepared catalysts was examined through the condensation reaction of benzaldehyde and ethylene glycol. The results showed that the catalysts exhibited high catalytic activity with a conversion rate of 88.3% under mild conditions. Furthermore, catalysts with a magnetization saturation of 53.5 emu g(-1) at room temperature were easily separated from the reaction mixture by using a 0.2 T permanent magnet and were reused 8 times without any significant decrease in catalytic activity. PMID:24178624

Zheng, Fang-Cai; Chen, Qian-Wang; Hu, Lin; Yan, Nan; Kong, Xiang-Kai

2014-01-21

 
 
 
 
201

Gold Nanoparticles on Mesoporous SiO2-Coated Magnetic Fe3O4 Spheres: A Magnetically Separatable Catalyst with Good Thermal Stability  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fe3O4 spheres with an average size of 273 nm were prepared in the presence of CTAB by a solvothermal method. The spheres were modified by a thin layer of SiO2, and then coated by mesoporous SiO2 (m-SiO2) films, by using TEOS as a precursor and CTAB as a soft template. The resulting m-SiO2/Fe3O4 spheres, with an average particle size of 320 nm, a high surface area (656 m2/g), and ordered nanopores (average pore size 2.5 nm), were loaded with gold nanoparticles (average size 3.3 nm). The presen...

2013-01-01

202

Engineered spin-valve type magnetoresistance in Fe3O4-CoFe2O4 core-shell nanoparticles  

Science.gov (United States)

Naturally occurring spin-valve-type magnetoresistance (SVMR), recently observed in Sr2FeMoO6 samples, suggests the possibility of decoupling the maximal resistance from the coercivity of the sample. Here we present the evidence that SVMR can be engineered in specifically designed and fabricated core-shell nanoparticle systems, realized here in terms of soft magnetic Fe3O4 as the core and hard magnetic insulator CoFe2O4 as the shell materials. We show that this provides a magnetically switchable tunnel barrier that controls the magnetoresistance of the system, instead of the magnetic properties of the magnetic grain material, Fe3O4, and thus establishing the feasibility of engineered SVMR structures.

Anil Kumar, P.; Ray, Sugata; Chakraverty, S.; Sarma, D. D.

2013-09-01

203

Prevention of acute graft-versus-host disease by magnetic nanoparticles of Fe3O4 combined with cyclosporin A in murine models  

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Full Text Available Jian Cheng1,*, Ying Zhou1,*, Baoan Chen1, Jun Wang1, Guohua Xia1, Nan Jin1, Jiahua Ding1, Chong Gao1, Gouming Chen2, Yushan Miao2, Weilan Li2, Ziling Liu3, Xuemei Wang11Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Pharmacy, Zhongda Hospital, Medical College, Southeast University, Nanjing, People’s Republic of China; 3The First Hospital of Jilin University, Changchun, Jilin, People’s Republic of China *These authors have contributed equally to this workObjective: To investigate the effect of magnetic nanoparticles (MNPs of Fe3O4 combined with cyclosporin A (CsA on acute graft-versus-host disease (aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT in murine models.Methods: BALB/c mice preconditioned with total-body irradiation generated aGVHD and then were followed with allo-HSCT from allogeneic C57BL/6. Recipient mice were randomly divided into five groups and then given different supportive care and followed up. The physical signs and median survival time (MST were recorded, peripheral blood cell counts were assessed, and histological changes of the main tissues were evaluated with hematoxylin-eosin staining. Furthermore, fluorescence polarization immunoassay was used to monitor the concentration of CsA.Results: The irradiated-only mice developed typical aGVHD, and the typical signs of aGVHD in the skin, liver, and intestine were observed by histopathological examination. Both CsA alone and in combination with Fe3O4 MNPs significantly prolonged the MST of recipient mice compared with both the control and the Fe3O4 MNPs groups. Notably, a combination of CsA with Fe3O4 MNPs can elevate the peripheral white blood cells and alleviate the symptoms of GVHD and the pathological damage after allo-HSCT. In addition, the concentration of CsA was higher in plasma, heart, liver, and spleen of recipient mice with supporting care of the combination of CsA with Fe3O4 MNPs than with CsA alone.Conclusion: Taken together, Fe3O4MNPs may be used as a carrier of immunosuppressive agents to alleviate GVHD after allo-HSCT in murine models.Keywords: allogenetic stem cell transplantation, mice, HSCT

Cheng J

2011-10-01

204

Gambogic acid-loaded magnetic Fe3O4 nanoparticles inhibit Panc-1 pancreatic cancer cell proliferation and migration by inactivating transcription factor ETS1  

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Full Text Available Cailian Wang1, Haijun Zhang1, Yan Chen1, Fangfang Shi1, Baoan Chen2,31Department of Oncology, 2Department of Hematology, Zhongda Hospital, 3Faculty of Oncology, Medical School, Southeast University, Nanjing, People’s Republic of ChinaBackground: E26 transformation-specific sequence-1 (ETS1 transcription factor plays important roles in both carcinogenesis and the progression of a wide range of malignancies. Aberrant ETS1 expression correlates with aggressive tumor behavior and a poorer prognosis in patients with various malignancies. The aim of the current study was to evaluate the efficacy of a drug delivery system utilizing gambogic acid-loaded magnetic Fe3O4 nanoparticles (GA-MNP- Fe3O4 on the suppression of ETS1-mediated cell proliferation and migration in Panc-1 pancreatic cancer cells.Methods: The effects caused by GA-MNP- Fe3O4 on the proliferation of Panc-1 pancreatic cancer cells were evaluated using a MTT (3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide assay while inhibition of tumor cell migration was investigated in a scratch assay. The expressions of ETS1, cyclin D1, urokinase-type plasminogen activator (u-PA, and VEGF (vascular endothelial growth factor were examined by Western blot to elucidate the possible mechanisms involved.Results: In Panc-1 pancreatic cancer cells, we observed that application of GA-MNP- Fe3O4 was able to suppress cancer cell proliferation and prevent cells from migrating effectively. After treatment, Panc-1 pancreatic cancer cells showed significantly decreased expression of ETS1, as well as its downstream target genes for cyclin D1, u-PA, and VEGF.Conclusion: Our novel finding reaffirmed the significance of ETS1 in the treatment of pancreatic cancer, and application of GA-MNP- Fe3O4 nanoparticles targeting ETS1 should be considered as a promising contribution for better pancreatic cancer care.Keywords: ETS1 transcription factor, gambogic acid, pancreatic cancer, magnetic nanoparticles

Wang C

2012-02-01

205

Fe3O4 nanoparticles prepared by the seeded-growth route for hyperthermia: electron magnetic resonance as a key tool to evaluate size distribution in magnetic nanoparticles.  

Science.gov (United States)

Monodispersed Fe3O4 nanoparticles have been synthesized by a thermal decomposition method based on the seeded-growth technique, achieving size tunable nanoparticles with high crystallinity and high saturation magnetization. EMR spectroscopy becomes a very efficient complementary tool to determine the fine details of size distributions of MNPs and even to estimate directly the size in a system composed of a given type of magnetic nanoparticles. The size and size dispersity affect directly the efficiency of MNPs for hyperthermia and EMR provides a direct evaluation of these characteristics almost exactly in the same preparation and with the same concentration as used in hyperthermia experiments. The correlation observed between the Specific Absorption Rate (SAR) and the effective gyromagnetic factor (geff) is extremely remarkable and renders a way to assess directly the heating capacity of a MNP system. PMID:24890223

Castellanos-Rubio, Idoia; Insausti, Maite; Garaio, Eneko; Gil de Muro, Izaskun; Plazaola, Fernando; Rojo, Teófilo; Lezama, Luis

2014-06-12

206

Immobilized transferrin Fe3O4@SiO2 nanoparticle with high doxorubicin loading for dual-targeted tumor drug delivery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wence Ding, Lin GuoKey Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of ChinaAbstract: Transferrin (Tf) was immobilized onto Fe3O4@SiO2 nanoparticles with high doxorubicin (DOX) loading (TfDMP), for dual targeting of cancer, by chemically coupling both Tf and DOX with dual-function magnetic nanoparticles (DMPs) using a multi-armed crosslinker, poly-L-glutamic acid. With high trappin...

2013-01-01

207

Core–shell Fe3O4–Au magnetic nanoparticles based nonenzymatic ultrasensitive electrochemiluminescence immunosensor using quantum dots functionalized graphene sheet as labels  

International Nuclear Information System (INIS)

Graphical abstract: Core–shell Fe3O4–Au magnetic nanoparticles and P-GS@QDs were prepared to immobilize Ab1 and Ab2 respectively and combined to fabricate a novel sandwich-type ECL immunosensor for detecting CA125 at low concentration. Highlights: ? ECL immunosensor for CA125 based on a microfluidic strategy with a homemade ECL cell was proposed. ? Core–shell Fe3O4–Au magnetic nanoparticles were employed as the carriers of the primary antibodies. ? CdTe quantum dots functionalized graphene sheet were used for signal amplification. -- Abstract: In this paper, a novel, low-cost electrochemiluminescence (ECL) immunosensor using core–shell Fe3O4–Au magnetic nanoparticles (AuMNPs) as the carriers of the primary antibody of carbohydrate antigen 125 (CA125) was designed. Graphene sheet (GS) with property of good conductivity and large surface area was a captivating candidate to amplify ECL signal. We successively synthesized functionalized GS by loading large amounts of quantum dots (QDs) onto the poly (diallyldimethyl-ammonium chloride) (PDDA) coated graphene sheet (P-GS@QDs) via self-assembly electrostatic reactions, which were used to label secondary antibodies. The ECL immunosensors coupled with a microfluidic strategy exhibited a wide detection range (0.005–50 U mL?1) and a low detection limit (1.2 mU mL?1) with the help of an external magnetic field to gather immunosensors. The method was evaluated with clinical serum sample, receiving good correlation with results from commercially available analytical procedure

2013-04-03

208

Adsorption of acidic, basic, and neutral proteins from aqueous samples using Fe3O4 magnetic nanoparticles modified with an ionic liquid  

International Nuclear Information System (INIS)

We have prepared and characterized Fe3O4 nanoparticles and their binary mixtures (IL-Fe3O4) with 1-hexyl-3-methylimidazolium bromide as ionic liquid for use in the adsorption of lysozyme (LYS), bovine serum albumin (BSA), and myoglobin (MYO). The optimum operational conditions for the adsorption of proteins (at 0.05-2.0 mg mL-1) were 4.0 mg mL-1 of nanoparticles and a contact time of 10 min. The maximum adsorption capacities are 455, 182 and 143 mg for LYS, BSA, and MYO per gram of adsorbent, respectively. The Langmuir model better fits the adsorption isotherms, with adsorption constants of 0.003, 0.015 and 0.008 L mg-1, in order, for LYS, BSA, MYO. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium adsorption capacity and correlation coefficients. The adsorption processes are endothermic. The proteins can be desorbed from the nanoparticles by using NaCl solution at pH 9.5, and the nanoparticles thus can be recycled. (author)

2013-01-01

209

Immobilized transferrin Fe3O4@SiO2 nanoparticle with high doxorubicin loading for dual-targeted tumor drug delivery  

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Full Text Available Wence Ding, Lin GuoKey Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, People's Republic of ChinaAbstract: Transferrin (Tf was immobilized onto Fe3O4@SiO2 nanoparticles with high doxorubicin (DOX loading (TfDMP, for dual targeting of cancer, by chemically coupling both Tf and DOX with dual-function magnetic nanoparticles (DMPs using a multi-armed crosslinker, poly-L-glutamic acid. With high trapping efficiency for magnetic targeting, TfDMP exhibits a Tf receptor-targeting function. Moreover, the DOX loading percentage of TfDMP is high, and can be controlled by adjusting the reactant ratio. TfDMP presents a narrow size distribution, and is sensitive to pH for drug release. Compared with DOX-coupled DMP without Tf modification (DDMP, TfDMP exhibits enhanced uptake by Tf receptor-expressing tumor cells, and displays stronger cancer cell cytotoxicity. This study provides an efficient method for the dual-targeted delivery of therapeutic agents to tumors, with controlled low carrier toxicity and high efficiency.Keywords: transferrin, Fe3O4@SiO2, nanoparticle, doxorubicin, targeted tumor

Ding W

2013-12-01

210

Response surface analysis of photocatalytic degradation of methyl tert-butyl ether by core/shell Fe3O4/ZnO nanoparticles.  

Science.gov (United States)

The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration sample magnetometer (VSM). Besides, specific surface area was also determined by BET method. The four effective factors including pH of the reaction mixture, Fe3O4/ZnO magnetic nanoparticles concentration, initial MTBE concentration and molar ratio of [H2O2]/ [MTBE] were optimized using response surface modeling (RSM). Using the four-factor-three-level Box-Behnken design, 29 runs were designed considering the effective ranges of the influential factors. The optimized values for the operational parameters under the respective constraints were obtained at PH of 7.2, Fe3O4/ZnO concentration of 1.78 g/L, initial MTBE concentration of 89.14 mg/L and [H2O2]/ [MTBE] molar ratio of 2.33. Moreover, kinetics of MTBE degradation was determined under optimum condition. The study about core/shell magnetic nanoparticles (MNPs) recycling were also carried out and after about four times, the percentage of the photocatalytic degradation was about 70%. PMID:24393372

Safari, Mojtaba; Rostami, Mohammad Hossein; Alizadeh, Mehriana; Alizadehbirjandi, Atefeh; Nakhli, Seyyed Ali Akbar; Aminzadeh, Reza

2014-01-01

211

Gold Nanoparticles on Mesoporous SiO2-Coated Magnetic Fe3O4 Spheres: A Magnetically Separatable Catalyst with Good Thermal Stability  

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Full Text Available Fe3O4 spheres with an average size of 273 nm were prepared in the presence of CTAB by a solvothermal method. The spheres were modified by a thin layer of SiO2, and then coated by mesoporous SiO2 (m-SiO2 films, by using TEOS as a precursor and CTAB as a soft template. The resulting m-SiO2/Fe3O4 spheres, with an average particle size of 320 nm, a high surface area (656 m2/g, and ordered nanopores (average pore size 2.5 nm, were loaded with gold nanoparticles (average size 3.3 nm. The presence of m-SiO2 coating could stabilize gold nanoparticles against sintering at 500 °C. The material showed better performance than a conventional Au/SiO2 catalyst in catalytic reduction of p-nitrophenol with NaBH4. It can be separated from the reaction mixture by a magnet and be recycled without obvious loss of catalytic activity. Relevant characterization by XRD, TEM, N2 adsorption-desorption, and magnetic measurements were conducted.

Huan Liu

2013-11-01

212

Gold nanoparticles on mesoporous SiO(2)-coated magnetic Fe(3)O(4)spheres: a magnetically separatable catalyst with good thermal stability.  

Science.gov (United States)

Fe3O4 spheres with an average size of 273 nm were prepared in the presence of CTAB by a solvothermal method. The spheres were modified by a thin layer of SiO2, and then coated by mesoporous SiO2 (m-SiO2) films, by using TEOS as a precursor and CTAB as a soft template. The resulting m-SiO2/Fe3O4 spheres, with an average particle size of 320 nm, a high surface area (656 m2/g), and ordered nanopores (average pore size 2.5 nm), were loaded with gold nanoparticles (average size 3.3 nm). The presence of m-SiO2 coating could stabilize gold nanoparticles against sintering at 500 °C. The material showed better performance than a conventional Au/SiO2 catalyst in catalytic reduction of p-nitrophenol with NaBH4. It can be separated from the reaction mixture by a magnet and be recycled without obvious loss of catalytic activity. Relevant characterization by XRD, TEM, N2 adsorption-desorption, and magnetic measurements were conducted. PMID:24252995

Liu, Huan; Lin, Chao; Ma, Zhen; Yu, Hongbo; Zhou, Shenghu

2013-01-01

213

Correlating material-specific layers and magnetic distributions within onion-like Fe3O4/MnO/?-Mn2O3 core/shell nanoparticles  

Science.gov (United States)

The magnetic responses of two nanoparticle systems comprised of Fe3O4/?-Mn2O3 (soft ferrimagnetic, FM/hard FM) and Fe3O4/MnO/?-Mn2O3 (soft FM/antiferromagnetic, AFM/hard FM) are compared, where the MnO serves to physically decouple the FM layers. Variation in the temperature and applied field allows for Small Angle Neutron Scattering (SANS) measurements of the magnetic moments both parallel and perpendicular to an applied field. Data for the bilayer particle indicate that the graded ferrimagnetic layers are coupled and respond to the field as a single unit. For the trilayer nanoparticles, magnetometry suggests a Curie temperature (TC) ~ 40 K for the outer ?-Mn2O3 component, yet SANS reveals an increase in the magnetization associated with outer layer that is perpendicular to the applied field above TC during magnetic reversal. This result suggests that the ?-Mn2O3 magnetically reorients relative to the applied field as the temperature is increased above 40 K.

Krycka, K. L.; Borchers, J. A.; Laver, M.; Salazar-Alvarez, G.; López-Ortega, A.; Estrader, M.; Suriñach, S.; Baró, M. D.; Sort, J.; Nogués, J.

2013-05-01

214

Multifunctional Fe3O4@P(St/MAA)@chitosan@Au core/shell nanoparticles for dual imaging and photothermal therapy.  

Science.gov (United States)

Merging different components into a single nanoparticle can exhibit profound impact on various biomedical applications including diagnostics, imaging, and therapy. However, retaining the unique properties of each component after integration has proven to be a significant challenge. Our previous research demonstrated that gold nanoshells on polystyrene spheres have potential in photohermal therapy. Here, we report a facile and green strategy to synthesize a multifunctional nanocomposite with Fe3O4 core coated gold nanoshells as dual imaging probes and photothermal agents. The as-prepared nanoparticles exhibit well-defined structure and excellent physical properties such as magnetic and plasmonic activities. Therefore, they were applied as contrast agents in magnetic resonance imaging (MRI) and dark field imaging (DFI). Besides, we demonstrated their potential application in photothermal therapy. Moreover, the obtained multifunctional nanoparticles have shown excellent biocompatibility for their low cytotoxicity and hemolyticity. PMID:23683167

Wang, Xuandong; Liu, Huiyu; Chen, Dong; Meng, Xianwei; Liu, Tianlong; Fu, Changhui; Hao, Nanjing; Zhang, Yanqi; Wu, Xiaoli; Ren, Jun; Tang, Fangqiong

2013-06-12

215

Bare and protein-conjugated Fe3O4 ferromagnetic nanoparticles for utilization in magnetically assisted hemodialysis: biocompatibility with human blood cells  

International Nuclear Information System (INIS)

Magnetically assisted hemodialysis is a development of conventional hemodialysis and is based on the circulation of ferromagnetic nanoparticle-targeted binding substance conjugates (FN-TBS Cs) in the bloodstream of the patient and their eventual removal by means of a 'magnetic dialyzer'. Presented here is an in vitro investigation on the biocompatibility of bare Fe3O4 FNs and Fe3O4-bovine serum albumin Cs with blood cells, namely red blood cells (RBCs), white blood cells (WBCs) and platelets (Plts). Atomic force microscopy (AFM) and optical microscopy (OM) enabled the examination of blood cells at the nanometer and micrometer level, respectively. The observations made on FN- and C-maturated blood samples are contrasted to those obtained on FN- and C-free reference blood samples subjected to exactly the same maturation procedure. Qualitatively, both AFM and OM revealed no changes in the overall shape of RBCs, WBCs and Plts. Incidents where bare FNs or Cs were bound onto the surface of RBCs or internalized by WBCs were very rare. Detailed examination by means of OM proved that impaired coagulation of Plts is not initiated/promoted either by FNs or Cs. Quantitatively, the statistical analysis of the obtained AFM images from RBC surfaces clearly revealed that the mean surface roughness of RBCs maturated with bare FNs or Cs was identical to the one of reference RBCs.

2008-12-17

216

Bifunctional polydopamine@Fe3O4 core-shell nanoparticles for electrochemical determination of lead(II) and cadmium(II).  

Science.gov (United States)

The present paper has focused on the potential application of the bifunctional polydopamine@Fe3O4 core-shell nanoparticles for development of a simple, stable and highly selective electrochemical method for metal ions monitoring in real samples. The electrochemical method is based on electrochemical preconcentration/reduction of metal ions onto a polydopamine@Fe3O4 modified magnetic glassy carbon electrode at -1.1 V (versus SCE) in 0.1 M pH 5.0 acetate solution containing Pb(2+) and Cd(2+) during 160 s, followed by subsequent anodic stripping. The proposed method has been demonstrated highly selective and sensitive detection of Pb(2+) and Cd(2+), with the calculated detection limits of 1.4×10(-11)M and 9.2×10(-11) M. Under the optimized conditions, the square wave anodic stripping voltammetry response of the modified electrode to Pb(2+) (or Cd(2+)) shows a linear concentration range of 5.0-600 nM (or 20-590 nM) with a correlation coefficient of 0.997 (or 0.994). Further, the proposed method has been performed to successfully detect Pb(2+) and Cd(2+) in aqueous effluent. PMID:23830422

Song, Qian; Li, Maoguo; Huang, Li; Wu, Qikang; Zhou, Yunyou; Wang, Yinling

2013-07-17

217

Bifunctional polydopamine@Fe3O4 core–shell nanoparticles for electrochemical determination of lead(II) and cadmium(II)  

International Nuclear Information System (INIS)

Highlights: •The bifunctional nanocomposites were synthesized. •A modified magnetic glassy carbon electrode was fabricated. •The electrode was used for the selective detection of Pb2+ and Cd2+ ions. •The proposed sensor features a wider linear range and higher sensitivity. -- Abstract: The present paper has focused on the potential application of the bifunctional polydopamine@Fe3O4 core–shell nanoparticles for development of a simple, stable and highly selective electrochemical method for metal ions monitoring in real samples. The electrochemical method is based on electrochemical preconcentration/reduction of metal ions onto a polydopamine@Fe3O4 modified magnetic glassy carbon electrode at ?1.1 V (versus SCE) in 0.1 M pH 5.0 acetate solution containing Pb2+ and Cd2+ during 160 s, followed by subsequent anodic stripping. The proposed method has been demonstrated highly selective and sensitive detection of Pb2+ and Cd2+, with the calculated detection limits of 1.4 × 10?11 M and 9.2 × 10?11 M. Under the optimized conditions, the square wave anodic stripping voltammetry response of the modified electrode to Pb2+ (or Cd2+) shows a linear concentration range of 5.0–600 nM (or 20–590 nM) with a correlation coefficient of 0.997 (or 0.994). Further, the proposed method has been performed to successfully detect Pb2+ and Cd2+ in aqueous effluent

2013-07-17

218

Immobilized transferrin Fe3O4@SiO2 nanoparticle with high doxorubicin loading for dual-targeted tumor drug delivery  

Science.gov (United States)

Transferrin (Tf) was immobilized onto Fe3O4@SiO2 nanoparticles with high doxorubicin (DOX) loading (TfDMP), for dual targeting of cancer, by chemically coupling both Tf and DOX with dual-function magnetic nanoparticles (DMPs) using a multi-armed crosslinker, poly-L-glutamic acid. With high trapping efficiency for magnetic targeting, TfDMP exhibits a Tf receptor-targeting function. Moreover, the DOX loading percentage of TfDMP is high, and can be controlled by adjusting the reactant ratio. TfDMP presents a narrow size distribution, and is sensitive to pH for drug release. Compared with DOX-coupled DMP without Tf modification (DDMP), TfDMP exhibits enhanced uptake by Tf receptor-expressing tumor cells, and displays stronger cancer cell cytotoxicity. This study provides an efficient method for the dual-targeted delivery of therapeutic agents to tumors, with controlled low carrier toxicity and high efficiency.

Ding, Wence; Guo, Lin

2013-01-01

219

Immobilized transferrin Fe3O4@SiO2 nanoparticle with high doxorubicin loading for dual-targeted tumor drug delivery.  

Science.gov (United States)

Transferrin (Tf) was immobilized onto Fe3O4@SiO2 nanoparticles with high doxorubicin (DOX) loading (TfDMP), for dual targeting of cancer, by chemically coupling both Tf and DOX with dual-function magnetic nanoparticles (DMPs) using a multi-armed crosslinker, poly-L-glutamic acid. With high trapping efficiency for magnetic targeting, TfDMP exhibits a Tf receptor-targeting function. Moreover, the DOX loading percentage of TfDMP is high, and can be controlled by adjusting the reactant ratio. TfDMP presents a narrow size distribution, and is sensitive to pH for drug release. Compared with DOX-coupled DMP without Tf modification (DDMP), TfDMP exhibits enhanced uptake by Tf receptor-expressing tumor cells, and displays stronger cancer cell cytotoxicity. This study provides an efficient method for the dual-targeted delivery of therapeutic agents to tumors, with controlled low carrier toxicity and high efficiency. PMID:24348038

Ding, Wence; Guo, Lin

2013-01-01

220

Fe3O4 magnetic core coated by silver and functionalized with N-acetyl cysteine as novel nanoparticles in ferritin adsorption  

International Nuclear Information System (INIS)

A novel metal-chelate affinity matrix utilizing N-acetyl cysteine as a metal chelating agent was synthesized. For this, magnetic Fe3O4 core was coated with silver by chemical reduction. Then, these magnetic silver nanoparticles were covered with N-acetyl cysteine, and Fe3+ was chelated to this modified magnetic silver nanoparticle. These magnetic nanoparticles were characterized by SEM, AFM, EDX, and ESR analysis. Synthesized nanoparticles were spherical and average size is found to be 69 nm. Fe3+ chelated magnetic silver nanoparticles were used for the adsorption of ferritin from its aqueous solution. Optimum conditions for the ferritin adsorption experiments were performed at pH 6.0 phosphate buffer and 25 °C of medium temperature and the maximum ferritin adsorption capacity is found to be 89.57 mg/g nanoparticle. Ferritin adsorption onto magnetic silver nanoparticles was increased with increasing ferritin concentration while adsorption capacity was decreased with increasing ionic strength. Affinity of the magnetic silver nanoparticles to the ferritin molecule was shown with SPR analysis. It was also observed that the adsorption capacity of the magnetic silver nanoparticles was not significantly changed after the five adsorption/desorption cycles.

2013-04-01

 
 
 
 
221

Diethanolamine-modified magnetic fluorescent Fe3O4@ZnS nanoparticles for ultrasensitive detection and removal of Cu2+.  

Science.gov (United States)

Currently, growing attention has been paid to the sensitive determination and removal of Cu2+ because excessive levels of Cu2+ could do harm to organisms. Herein, a novel diethanolamine-modified magnetic fluorescent Fe3O4@ZnS nanoparticle (MFNP) for simultaneous detection and removal of Cu2+ was designed and synthesized through dithiocarbamate linkage strategy. The characterization of MFNP was confirmed by transmission electron microscope (TEM), infrared (IR) and emission spectra. The results showed that MFNP could quantificationally detect Cu2+ with high sensitivity and selectivity under a broad pH range (pH 4.5-9). The removal of Cu2+ was achieved by the aggregation-induced sedimentation (AIS) strategy and by external magnetic field. PMID:24758043

Yang, Peilun; Zhu, Baocun; Zhao, Jie; Yu, Haiqin; Wei, Qin; Du, Bin

2014-07-01

222

Synthesis and characterization of Mn0.5Zn0.5Fe2O4 and Fe3O4 nanoparticle ferrofluids for thermo-electric conversion  

Science.gov (United States)

Ferrofluids containing nanoparticles of Mn0.5Zn0.5Fe2O4 (MZ5) and Fe3O4 (magnetite) have been examined as potential thermal transport media and energy harvesting materials. The ferrofluids were synthesized by chemical co-precipitation and characterized by EDX to determine composition and by TEM to determine particle size and agglomeration. A range of particle coatings and carrier fluids were used to complete the fluid preparation. Commercially available ferrofluids were tested in custom built rigs to demonstrate both thermal pumping (for waste heat removal applications) and power induction (for power conversion and energy harvesting applications). The results indicate that simple ferrofluids possess the necessary properties to remove waste heat, either into thermal storage or for conversion to electrical power.

Sansom, C. L.; Jones, P.; Dorey, R. A.; Beck, C.; Stanhope-Bosumpim, A.; Peterson, J.

2013-06-01

223

Study on synthesis of poly(GMA)-grafted Fe3O4/SiOX magnetic nanoparticles using atom transfer radical polymerization and their application for lipase immobilization  

International Nuclear Information System (INIS)

Functionalized superparamagnetic particles were prepared by atom transfer radical polymerization of glycidyl methacrylate onto the surface of modified Fe3O4/SiOX nanoparticles. The obtained particles were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). Candida rugosa lipase was covalently immobilized on the magnetic particles in mild condition via covalent binding with a higher activity recovery. The resulting immobilized lipase had better resistance to pH and temperature inactivation in comparison to free lipase, the adaptive pH and temperature ranges of lipase were widened, and it exhibited good thermal stability and reusability.

2011-02-15

224

Particle size effects on the magnetic behaviour of 5 to 11 nm Fe3O4 nanoparticles coated with oleic acid  

Science.gov (United States)

The magnetic behaviour of 5 to 11 nm magnetite (Fe3O4) nanoparticles (NPs) was measured at various temperatures (Ts) from 20 to 400 K. The particles were fabricated via thermal decomposition of an iron precursor, and involved a coating of the particles with oleic acid. The particle size distribution was analysed by XRD measurements and TEM imaging. Magnetization loops, measured at various Ts, indicate a superparamagnetic behaviour at high T and the occurrence of hysteresis at low T, with a stronger coercivity for the larger particles. Zero-Field-Cooling (ZFC) and Field Cooling (FC) curves indicate a superparamagnetic behaviour, with a blocking temperature varying significantly with the particle size. Namely, the peak temperature, Tmax, increases from 30 K to 170 K when the particle size increases from 5 nm to 11nm. Magnetic couplings between particles appear stronger for larger particles.

Chesnel, K.; Trevino, M.; Cai, Y.; Hancock, J. M.; Smith, S. J.; Harrison, R. G.

2014-06-01

225

Comparison of the magnetic, radiolabeling, hyperthermic and biodistribution properties of hybrid nanoparticles bearing CoFe2O4 and Fe3O4 metal cores  

Science.gov (United States)

Metal oxide nanoparticles, hybridized with various polymeric chemicals, represent a novel and breakthrough application in drug delivery, hyperthermia treatment and imaging techniques. Radiolabeling of these nanoformulations can result in new and attractive dual-imaging agents as well as provide accurate in vivo information on their biodistribution profile. In this paper a comparison study has been made between two of the most promising hybrid core-shell nanosystems, bearing either magnetite (Fe3O4) or cobalt ferrite (CoFe2O4) cores, regarding their magnetic, radiolabeling, hyperthermic and biodistribution properties. While hyperthermic properties were found to be affected by the metal-core type, the radiolabeling ability and the in vivo fate of the nanoformulations seem to depend critically on the size and the shell composition.

Psimadas, D.; Baldi, G.; Ravagli, C.; Comes Franchini, M.; Locatelli, E.; Innocenti, C.; Sangregorio, C.; Loudos, G.

2014-01-01

226

Comparison of the magnetic, radiolabeling, hyperthermic and biodistribution properties of hybrid nanoparticles bearing CoFe2O4 and Fe3O4 metal cores.  

Science.gov (United States)

Metal oxide nanoparticles, hybridized with various polymeric chemicals, represent a novel and breakthrough application in drug delivery, hyperthermia treatment and imaging techniques. Radiolabeling of these nanoformulations can result in new and attractive dual-imaging agents as well as provide accurate in vivo information on their biodistribution profile. In this paper a comparison study has been made between two of the most promising hybrid core-shell nanosystems, bearing either magnetite (Fe3O4) or cobalt ferrite (CoFe2O4) cores, regarding their magnetic, radiolabeling, hyperthermic and biodistribution properties. While hyperthermic properties were found to be affected by the metal-core type, the radiolabeling ability and the in vivo fate of the nanoformulations seem to depend critically on the size and the shell composition. PMID:24334365

Psimadas, D; Baldi, G; Ravagli, C; Comes Franchini, M; Locatelli, E; Innocenti, C; Sangregorio, C; Loudos, G

2014-01-17

227

Click chemistry: a new facile and efficient strategy for the preparation of Fe3O4 nanoparticles covalently functionalized with IDA-Cu and their application in the depletion of abundant protein in blood samples.  

Science.gov (United States)

In this study, we report a novel method to synthesize core-shell structured Fe(3)O(4) nanoparticles (NPs) covalently functionalized with iminodiacetic acid (IDA) via click chemistry between the azide and alkyne groups and charged with Cu(2+). Firstly, the Fe(3)O(4)@SiO(2) NPs were obtained using tetraethoxysilane (TEOS) to form a silica shell on the surface of the Fe(3)O(4) core. The azide group-modified Fe(3)O(4)@SiO(2) NPs were obtained by a sol-gel process using 3-azidopropyltriethoxysilane (AzPTES) as the silane agent. Fe(3)O(4)@SiO(2)-N(3) was directly reacted with N-propargyl iminodiacetic via click chemistry, in the presence of a Cu(I) catalyst, to acquire the IDA-modified Fe(3)O(4) NPs. Finally, through the addition of Cu(2+), the Fe(3)O(4)@SiO(2)-IDA-Cu NP product was obtained. The morphology, structure and composition of the NPs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resulting NPs showed a strong magnetic response to an externally applied magnetic field, a high adsorption capacity and excellent specificity towards hemoglobin (Hb). In addition, the Fe(3)O(4)@SiO(2)-IDA-Cu NPs can be used for the selective removal of abundant Hb protein in bovine and human blood samples. PMID:22941423

Jian, Guiqin; Liu, Yuxing; He, Xiwen; Chen, Langxing; Zhang, Yukui

2012-10-21

228

An amperometric acetylcholinesterase sensor based on Fe3O4 nanoparticle/multi-walled carbon nanotube-modified ITO-coated glass plate for the detection of pesticides  

International Nuclear Information System (INIS)

Highlights: ? Constructed AChE biosensor based on AChE/Fe3O4NPs/c-MWCNT/ITO electrode. ? Enzyme electrode was characterized by AFM, FTIR, CV and EIS. ? Detection limit and working range of biosensor were 0.1 nM and 0.1–100 nM. ? Half life of enzyme electrode was 3 months. ? Biosensor measured pesticides in environmental and food samples. - Abstract: A method is described for the construction of a highly sensitive electrochemical biosensor for the detection of malathion, chlorpyrifos, monocrotophos and endosulfan based on covalent immobilization of acetylcholinesterase (AChE) on iron oxide nanoparticles (Fe3O4NPs)-decorated carboxylated multi-walled carbon nanotubes (c-MWCNTs) electrodeposited onto indium tin oxide (ITO)-coated glass plate. Transmission electron microscopic (TEM) and UV analysis of nanocomposite materials demonstrated that Fe3O4NPs were well deposited on the outer walls of c-MWCNTs. The modified electrode was characterized by atomic force microscopy (AFM), cyclic voltammetry (CV), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS). The resulting biosensor exhibited a linear response for acetylthiocholine in a concentration range of 0.1–700 ?mol L?1 with a remarkable sensitivity of 0.402 mA/?mol L?1. Under optimum conditions, the inhibition rates of pesticides were proportional to their concentrations in the range of 0.1–70 nmol L?1, 0.1–50 nmol L?1, 0.1–70 nmol L?1 and 0.1–100 nmol L?1 for malathion, chlorpyrifos, monocrotophos and endosulfan, respectively. The detection limit of the biosensor for all pesticides was 0.1 nmol L?1 at a signal-to-noise ratio of 3. The biosensor showed good reproducibility, no interference by metal ions and long-term stability. The measurement results obtained by the present biosensor were in good agreement with those obtained by the standard gas chromatography–mass spectrometry method. The biosensor was employed for the determination of pesticides in environmental and food samples.

2012-04-15

229

A Novel DNA Nanosensor Based on CdSe/ZnS Quantum Dots and Synthesized Fe3O4 Magnetic Nanoparticles  

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Full Text Available Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4 nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.

Roozbeh Hushiarian

2014-04-01

230

A novel DNA nanosensor based on CdSe/ZnS quantum dots and synthesized Fe3O4 magnetic nanoparticles.  

Science.gov (United States)

Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4) nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices. PMID:24722589

Hushiarian, Roozbeh; Yusof, Nor Azah; Abdullah, Abdul Halim; Ahmad, Shahrul Ainliah Alang; Dutse, Sabo Wada

2014-01-01

231

Facile and solvent-free routes for the synthesis of size-controllable Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Magnetite nanoparticles are one of the most important materials that are widely used in both medically diagnostic and therapeutic research. In this paper, we present some facile and non-toxic synthetic approaches for size-controllable preparations of magnetite nanoparticles, which are appropriate for biomedical applications, namely (i) co-precipitation; (ii) reduction–precipitation and (iii) oxidation–precipitation. Magnetic characterizations of the obtained nanoparticles have been studied and discussed. The oxidation precipitation route was chosen for investigation of the dependence of kinetic driven activation energy and that of coercive force on particle size (and temperature) during the course of the reaction. The structural–magnetic behavior was also correlated. Being solvent and surfactant-free, these methods are advantageous for synthesis and further functionalization towards biomedical applications

2010-09-01

232

A facile method for the room-temperature synthesis of water-soluble magnetic Fe3O4 nanoparticles: Combination of in situ synthesis and decomposition of polymer hydrogel  

International Nuclear Information System (INIS)

Highlights: ? A facile room-temperature method for achieving water-soluble magnetic Fe3O4 nanoparticles (NPs) by combining in situ synthesis and decomposition of magnetic polymer hydrogel has been demonstrated. ? The Fe3O4 NPs with average diameters of 6.3-8.3 nm were synthesized in a crosslinked polyacrylamide hydrogel. ? The saturation magnetization was 44.6 and 54.7 emu g-1 at 300 K and 5 K, respectively. ? The dried magnetic Fe3O4 NPs were easily dispersed in alkaline aqueous media. ? This study would be prospect for preparing functional water-soluble NPs used in metals and semiconductors. - Abstract: We propose and demonstrate a facile room-temperature synthetic method for obtaining water-soluble magnetic Fe3O4 nanoparticles (NPs) by combining the in situ synthesis and decomposition of a magnetic polymer hydrogel. The Fe3O4 NPs with average diameters of 6.3-8.3 nm were synthesized in a cross-linked polyacrylamide (PAAm) hydrogel by coprecipitating iron ions. The decomposition of the magnetic polymer hydrogel by an aqueous solution of sodium hydroxide led to the transfer of Fe3O4 NPs into the aqueous medium. The NPs can be dispersed stably in water for more than three months. The Fe3O4 NPs were characterized by X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), transmission electron microscope (TEM), and Fourier transform infrared spectroscopy (FT-IR). The saturation magnetization of the Fe3O4 NPs was 44.6 and 54.7 emu g-1 at 300 K and 5 K, respectively. The dried magnetic Fe3O4 NPs were easily dispersed in alkaline aqueous media (pH > ?8) and kept stable for a long time. This room-temperature synthetic method for water-soluble magnetic Fe3O4 NPs can be expected for wide applications in the preparation of functional water-soluble NPs, such as those used in metals and semiconductors.

2011-10-17

233

Characterization of the biocompatible magnetic colloid on the basis of Fe3O4 nanoparticles coated with dextran, used as contrast agent in magnetic resonance imaging.  

Science.gov (United States)

The magnetic resonance imaging contrast agent, the so-called Endorem colloidal suspension on the basis of superparamagnetic iron oxide nanoparticles (mean diameter of 5.5 nm) coated with dextran, were characterized on the basis of several measurement techniques to determine the parameters of their most important physical and chemical properties. It is assumed that each nanoparticle is consisted of Fe3O4 monodomain and it was observed that its oxidation to gamma-Fe2O3 occurs at 253.1 degrees C. The Mössbauer spectroscopy have shown a superparamagnetic behavior of the magnetic nanoparticles. The Magnetic Resonance results show an increase of the relaxation times T1, T2, and T2* with decreasing concentration of iron oxide nanoparticles. The relaxation effects of SPIONs contrast agents are influenced by their local concentration as well as the applied field strength and the environment in which these agents interact with surrounding protons. The proton relaxation rates presented a linear behavior with concentration. The measured values of thermo-optic coefficient dn/dT, thermal conductivity kappa, optical birefringence delta n0, nonlinear refractive index n2, nonlinear absorption beta' and third-order nonlinear susceptibility |chi(3)| are also reported. PMID:21128393

Gamarra, L F; Amaro, E; Alves, S; Soga, D; Pontuschka, W M; Mamani, J B; Carneiro, S M; Brito, G E S; Figueiredo Neto, A M

2010-07-01

234

Preparation and in vitro evaluation of doxorubicin-loaded Fe3O4 magnetic nanoparticles modified with biocompatible copolymers  

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Abolfazl Akbarzadeh1, Haleh Mikaeili2, Nosratollah Zarghami3, Rahmati Mohammad3, Amin Barkhordari3, Soodabeh Davaran21Drug Applied Research Center, 2Tuberculosis and Lung Disease Research Center of Tabriz, 3Department of Clinical Biochemistry and Laboratory Medicine, Division of Medical Biotechnology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IranBackground: Superparamagnetic iron oxide nanoparticles are attractive materials that have been widely used in medicine for...

Akbarzadeh A; Mikaeili H; Zarghami N; Mohammad R; Barkhordari A; Davaran S

2012-01-01

235

Controlling anisotropic drug diffusion in lipid-Fe3O4 nanoparticle hybrid mesophases by magnetic alignment.  

Science.gov (United States)

We present a new strategy to control the anisotropic diffusion of hydrophilic drugs in lyotropic liquid crystals via the dispersion of magnetic nanoparticles in the mesophase, followed by reorientation of the mesophase domains via an external magnetic field. We select a lipid reverse hexagonal phase doped with magnetic iron oxide nanoparticles and glucose and caffeine as model hybrid mesophase and hydrophilic drugs, respectively. Upon cooling through the disorder-order phase transition of the hexagonal phase and under exposure to an external moderate magnetic field (1.1 T), both the nanoparticles and the hexagonal domains align with their columnar axes along the field direction. As a result, the water nanochannels of the inverted hexagonal domains also align parallel to the field direction, leading to a drug diffusion coefficient parallel to the field direction much larger than what was measured perpendicularly: in the case of glucose, for example, this difference in diffusion coefficients approaches 1 order of magnitude. Drug diffusion of the unaligned reverse hexagonal phase, which consists of randomly distributed domains, shows values in between the parallel and transversal diffusion values. This study shows that modifying the overall alignment of anisotropic mesophases via moderate external fields is a valuable means to control the corresponding transport tensor of the mesophase and demonstrates that the orientation of the domains plays an important role in the diffusion process of foreign hydrophilic molecules. PMID:23302008

Vallooran, Jijo J; Negrini, Renata; Mezzenga, Raffaele

2013-01-29

236

PLLA- Fe3O4 nanocomposites  

Science.gov (United States)

In the present work magnetite nanoparticules and PLLA- Fe3O4 nanocomposites were prepared by high frequency ultrasound. The influence of pH on nanoparticle size was studied, showing that the particle size decreased as the pH increased. In the composites an interaction between the magnetite nanoparticles and the PLLA matrix was observed by FTIR. Magnetic properties were studied using a VSM, and a superparamegnetic behavior was observed for magnetite nanoparticles, but for the composite a magnetic attenuation was observed due to the polymeric matrix.

Albano, Carmen; Gonzalez, Gema; Naranjo, Claudio

2012-07-01

237

Sensitive and selective detection of Ag+ in aqueous solutions using Fe3O4@Au nanoparticles as smart electrochemical nanosensors.  

Science.gov (United States)

Owing to the selective deposition reaction on the surface of magnetic nanoparticles, we reported a simple and selective magnetic electrochemical method for the detection of Ag(+) ions in aqueous solutions. The analyte deposited on the nanoparticles was brought to the surface of a homemade magnetic electrode and detected electrochemically in 0.1 mol/L KCl solution based on the reaction of Ag0 transferred to AgCl. Under the optimal conditions, the linear response range of Ag(+) ions was 0.117-17.7 ?mol/L (R(2)=0.9909) with a detection limit of 59 nmol/L (S/N=3). A series of repeatability measurements 1.0 ?mol/L Ag(+) gave reproducible results with a relative standard deviation (RSD) of 4.5% (n=11). The interference from other metal cations can be eliminated by adding EDTA as a co-additive to mask the metal cations. The recoveries ranging from 98.6% to 103.99% after standard additions demonstrate that this sensor has great potential in practical applications. The advantages of this developed method include remarkable simplicity, low cost, and no requirement for probe preparation, among others. PMID:24148443

Yang, Huicui; Liu, Xiaoxiao; Fei, Ruihua; Hu, Yonggang

2013-11-15

238

Magnetic loading of TiO2/SiO2/Fe3O4 nanoparticles on electrode surface for photoelectrocatalytic degradation of diclofenac  

International Nuclear Information System (INIS)

Highlights: ? Magnetic TSF nanoparticles are immobilized on electrode surface with aid of magnet. ? Magnetically attached TSF electrode shows high photoelectrochemical activity. ? Diclofenac is effectively degraded on TSF-loaded electrode by photoelectrocatalysis. ? Photoelectrocatalytic degradation of diclofenac is monitored with voltammetry. - Abstract: A novel magnetic nanomaterials-loaded electrode developed for photoelectrocatalytic (PEC) treatment of pollutants was described. Prior to electrode fabrication, magnetic TiO2/SiO2/Fe3O4 (TSF) nanoparticles were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR measurements. The nanoparticles were dispersed in ethanol and then immobilized on a graphite electrode surface with aid of magnet to obtain a TSF-loaded electrode with high photoelectrochemical activity. The performance of the TSF-loaded electrode was tested by comparing the PEC degradation of methylene blue in the presence and absence of magnet. The magnetically attached TSF electrode showed higher PEC degradation efficiency with desirable stability. Such a TSF-loaded electrode was applied to PEC degradation of diclofenac. After 45 min PEC treatment, 95.3% of diclofenac was degraded on the magnetically attached TSF electrode.

2011-11-30

239

Hybrid Fe3O4@amino cellulose nanoparticles in organic media--heterogeneous ligands for atom transfer radical polymerizations.  

Science.gov (United States)

We demonstrate an efficient strategy for the preparation of well-dispersed hybrid particles in organic media via a combination of the solution-based formation of magnetic nanoparticles (MNPs) and subsequent coating with amino celluloses of different degrees of polymerization. The coating process was verified by a combination of light scattering, thermogravimetry, and magnetic techniques. Further, the hybrid particles exhibit an average diameter of roughly 8 nm, as demonstrated by electron microscopy and light scattering. The stability of the so-called MNP@AC(x) hybrid particles (x represents the average degree of polymerization of the amino cellulose) in polar organic solvents such as DMAc was exploited by using the materials as heterogeneous ligands in the atom transfer radical polymerization (ATRP) of styrene. We could show that PS with a near-narrow molecular weight distribution (PDIsprepared. The MNP@AC(x) particles could be separated from the reaction mixture afterwards by an external magnetic field and reused in further polymerizations. PMID:23079041

Fidale, Ludmila C; Nikolajski, Melanie; Rudolph, Tobias; Dutz, Silvio; Schacher, Felix H; Heinze, Thomas

2013-01-15

240

Protein adsorption onto Fe3O4 nanoparticles with opposite surface charge and its impact on cell uptake  

CERN Document Server

Nanoparticles (NPs) engineered for biomedical applications are meant to be in contact with protein-rich physiological fluids. These proteins are usually adsorbed onto the NP surface, forming a swaddling layer called protein corona that influences cell internalization. We present a study on protein adsorption onto different magnetic NPs (MNPs) when immersed in cell culture medium, and how these changes affect the cellular uptake. Two colloids with magnetite cores of 25 nm, same hydrodynamic size and opposite surface charge were in situ coated with (a) positive polyethyleneimine (PEI-MNPs) and (b) negative poly(acrylic acid) (PAA-MNPs). After few minutes of incubation in cell culture medium the wrapping of the MNPs by protein adsorption resulted in a 5-fold size increase. After 24 h of incubation large MNP-protein aggregates with hydrodynamic sizes 1500 to 3000 nm (PAA-MNPs and PEI-MNPs respectively) were observed. Each cluster contained an estimated number of magnetic cores between 450 and 1000, indicating the...

Catalayud, M P; Raffa, V; Riggio, C; Ibarra, M R; Goya, G F

2014-01-01

 
 
 
 
241

The C(RgdyK)-conjugated Fe3O4 nanoparticles with high drug load for dual-targeting integrin alpha(v)beta3-expressing cancer cells.  

Science.gov (United States)

A novel drug delivery system c(RGDyK)-modified Fe3O4 nanoparticles with high DOX load (R-DMP), which combines magnetic targeting, integrin alpha(v)beta3 targeting and high drug loading properties, was developed by chemical coupling both doxorubicin and peptide c(RGDyK) on the synthetic dual function magnetic nanoparticles (DMP) using a multi-hand cross-linker poly-L-glutamic acid. R-DMP has high drug loading ratio and trapping efficiency for magnetic targeting, and the drug loading ratio can be controlled by adjusting the reactant ratio. Moreover, R-DMP presents narrow size distribution and is sensitive to pH for drug releasing. Compare with those of doxorubicin coupled DMP without peptide c(RGDyK) modification, D-DMP shows enhanced uptake by integrin alpha(v)beta3 targeting expressing tumor cells and displays stronger cancer cell cytotoxicity. This investigate provides a new approach for the dual-targeted delivery of therapeutic agents to tumors with controlled low carrier toxicity and high efficiency. PMID:24757954

Guo, Lin; Ding, Wence; Zheng, Li-Min

2014-07-01

242

Magnetic Reversal of Onion-Like Fe3O4MnO?-Mn2O3 CoreShellShell Nanoparticles  

Science.gov (United States)

Magnetic nanoparticles offer potential for biomedical and data storage applications, especially with exchange bias to overcome the superparamagnetic limit. Here we study the role of an antiferromagnetic layer sandwiched between a soft ferrimagnetic core and hard ferrimagnetic shell. The nanoparticles studied consist of 3 nm (diameter) Fe3O4 50-60 nm thick MnO shell 5 nm thick ?-Mn2O3 shell [1]. Small-angle neutron scattering (SANS) probes both structural and magnetic morphology. SANS reveals that during reversal from 5 T to -5 T at 5 K, there is an increase in spins oriented perpendicular to the applied field. As the temperature is increased to 150 K (above the 123 K Néel temperature of MnO) evidence of an enhanced magnetism from within the MnO shell is observed. Finally, the scattering pattern shifts (indicating a change in the relative magnetism as a function of radius) between 5 K and 50 K. [4pt] [1] A. López-Ortega et al., Nanoscale 4, 5138 (2012); Salazar-Alvarez et al., J. Am. Chem. Soc., 133, 16738 (2011)

Krycka, Kathryn; Borchers, Julie; Laver, Mark; Salazar-Alverez, German; Lopez-Ortega, Alberto; Estrader, Marta; Surinach, Santiago; Baro, Maria; Sort, Jordi; Nogues, Josep

2013-03-01

243

Aluminium hydroxide stabilised MnFe2O4 and Fe3O4 nanoparticles as dual-modality contrasts agent for MRI and PET imaging.  

Science.gov (United States)

Magnetic nanoparticles (NPs) MnFe2O4 and Fe3O4 were stabilised by depositing an Al(OH)3 layer via a hydrolysis process. The particles displayed excellent colloidal stability in water and a high affinity to [(18)F]-fluoride and bisphosphonate groups. A high radiolabeling efficiency, 97% for (18)F-fluoride and 100% for (64)Cu-bisphosphonate conjugate, was achieved by simply incubating NPs with radioactivity solution at room temperature for 5 min. The properties of particles were strongly dependant on the thickness and hardness of the Al(OH)3 layer which could in turn be controlled by the hydrolysis method. The application of these Al(OH)3 coated magnetic NPs in molecular imaging has been further explored. The results demonstrated that these NPs are potential candidates as dual modal probes for MR and PET. In vivo PET imaging showed a slow release of (18)F from NPs, but no sign of efflux of (64)Cu. PMID:24768194

Cui, Xianjin; Belo, Salome; Krüger, Dirk; Yan, Yong; de Rosales, Rafael T M; Jauregui-Osoro, Maite; Ye, Haitao; Su, Shi; Mathe, Domokos; Kovács, Noémi; Horváth, Ildikó; Semjeni, Mariann; Sunassee, Kavitha; Szigeti, Krisztian; Green, Mark A; Blower, Philip J

2014-07-01

244

Aluminium hydroxide stabilised MnFe2O4 and Fe3O4 nanoparticles as dual-modality contrasts agent for MRI and PET imaging  

Science.gov (United States)

Magnetic nanoparticles (NPs) MnFe2O4 and Fe3O4 were stabilised by depositing an Al(OH)3 layer via a hydrolysis process. The particles displayed excellent colloidal stability in water and a high affinity to [18F]-fluoride and bisphosphonate groups. A high radiolabeling efficiency, 97% for 18F-fluoride and 100% for 64Cu-bisphosphonate conjugate, was achieved by simply incubating NPs with radioactivity solution at room temperature for 5 min. The properties of particles were strongly dependant on the thickness and hardness of the Al(OH)3 layer which could in turn be controlled by the hydrolysis method. The application of these Al(OH)3 coated magnetic NPs in molecular imaging has been further explored. The results demonstrated that these NPs are potential candidates as dual modal probes for MR and PET. In vivo PET imaging showed a slow release of 18F from NPs, but no sign of efflux of 64Cu.

Cui, Xianjin; Belo, Salome; Kruger, Dirk; Yan, Yong; de Rosales, Rafael T.M.; Jauregui-Osoro, Maite; Ye, Haitao; Su, Shi; Mathe, Domokos; Kovacs, Noemi; Horvath, Ildiko; Semjeni, Mariann; Sunassee, Kavitha; Szigeti, Krisztian; Green, Mark A.; Blower, Philip J.

2014-01-01

245

Study of the intra-arterial distribution of Fe3O4 nanoparticles in a model of colorectal neoplasm induced in rat liver by MRI and spectrometry  

Directory of Open Access Journals (Sweden)

Full Text Available José J Echevarria-Uraga,1 Ignacio García-Alonso,2 Fernando Plazaola,3 Maite Insausti,3 Néstor Etxebarria,3 Alberto Saiz-López,4 Begoña Fernández-Ruanova51Radiology Department, Hospital de Galdakao-Usánsolo, Bizkaia, Spain; 2Experimental Surgery Laboratory, Medicine Faculty, University of the Basque Country, Bizkaia, Spain; 3Faculty of Science and Technology, University of the Basque Country, Bizkaia, Spain; 4Pathology Department, Hospital de Galdakao-Usánsolo, Bizkaia, Spain; 5Osatek SA Unidad del Hospital de Galdakao-Usánsolo, Bizkaia, SpainPurpose: To evaluate, in an experimental model, the reliability of MRI for determining whether a higher iron concentration was obtained in tumor tissue than in normal liver parenchyma after intra-arterial administration of Fe3O4 lipophilic nanoparticles.Materials and methods: WAG/RijCrl rats were inoculated in the left hepatic lobe with 25,000 syngeneic CC-531 colon adenocarcinoma cells, after which they were randomized into two groups: control (CG and infused (IG. After confirming tumor induction, the IG rats received intra-arterial suspensions of Fe3O4 nanoparticles (2.6 mg in Lipiodol® (0.15 mL. To calculate the iron concentration, [Fe], in the tumor and liver tissues of both groups of rats, measurements of signal intensity from the tumors, healthy liver tissue, and paravertebral muscles were made on a 1.5T MRI system in gradient-echo DP* and T2*-weighted sequences. In addition, samples were collected to quantify the [Fe] by inductively coupled plasma-mass spectrometry (ICP-MS, as well as for histological analysis. Statistical analysis was performed with non-parametric tests, and Bland–Altman plots were produced; P values <0.05 were considered significant.Results: In the CG rats (n = 23, the mean [Fe] values estimated by MRI and ICP-MS were 13.2 µmol • g-1 and 5.9 µmol • g-1, respectively, in the tumors, and 19.0 µmol • g-1 and 11.7 µmol • g-1, respectively, in the hepatic tissue. In the IG rats (n = 19, the values obtained by MRI and ICP-MS were 148.9 µmol • g-1 and 9.4 µmol • g-1, respectively, in the tumors, and 115.3 µmol • g-1 and 11.6 µmol • g-1, respectively, in the healthy liver tissue. The IG results revealed a clear disagreement between MRI and ICP-MS. In the comparative analysis between the groups regarding the [Fe] values obtained by ICP-MS, significant differences were found for the tumor samples (P < 0.001, but not for the hepatic tissue (P = 0.92. Under microscopy, scattered intravascular deposits of nanoparticles were observed, especially in the tumors.Conclusion: ICP-MS demonstrated significant uptake of exogenous iron in tumor tissue. MRI was useful for quantifying the [Fe] in the different tissues in the CG animals, but not in the IG animals. Although the irregular distribution of nanoparticles caused an important bias in the measurements obtained by MRI, the relative increase in iron content inside the tumor was suggested.Keywords: liver neoplasm, hepatic arterial infusion, ferromagnetic particle, iron concentration, MRI, spectrometry 

Echevarria-Uraga JJ

2012-05-01

246

Anomalous Magnetic Properties of Nanoparticles Arising from Defect Structures : Topotaxial Oxidation of Fe1-xO|Fe3-?O4 Core|Shell Nanocubes to Single-Phase Particles  

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Here we demonstrate that the anomalous magnetic properties of iron oxide nanoparticles are correlated with defects in their interior. We studied the evolution of microstructure and magnetic properties of biphasic core|shell Fe1–xO|Fe3??O4 nanoparticles synthesized by thermal decomposition during their topotaxial oxidation to single-phase nanoparticles. Geometric phase analysis of high-resolution electron microscopy images reveals a large interfacial strain at the core|shell interface and...

Wetterskog, Erik; Tai, Cheuk-wai; Grins, Jekabs; Bergstro?m, Lennart; Salazar-alvarez, German

2013-01-01

247

Fe3O4 nanoparticle loaded paclitaxel induce multiple myeloma apoptosis by cell cycle arrest and increase cleavage of caspases in vitro  

International Nuclear Information System (INIS)

Multiple myeloma (MM) still remains an incurable disease in spite of extending the patient survival by new therapies. The hypothesis of cancer stem cells (CSCs) states that although chemotherapy kills most tumor cells, it is believed to leave a reservoir of CSCs that allows the tumor cell propagation. The objective of this research was to evaluate the therapeutic effect of new paclitaxel-Fe3O4 nanoparticles (PTX-NPs) with an average size range of 7.17 ± 1.31 nm on MM CSCs in vitro. The characteristics of CD138?CD34? cells, isolated from human MM RPMI 8226 and NCI-H929 cell lines by the magnetic associated cell sorting method, were identified by the assays of colony formation, cell proliferation, drug resistance, cell migration, and tumorigenicity in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice, respectively. Inhibitory effects of PTX-NPs on CD138?CD34? cells were evaluated by a variety of assays in vitro. The results showed that the CD138?CD34? cells were capable of forming colonies, exhibited high proliferative and migratory ability, possessed a strong drug resistance, and had powerful tumorigenicity in NOD/SCID mice compared to non-CD138?CD34? cells. PTX-NPs significantly inhibited CD138? CD34? cell viability and invasive ability, and resulted in G0/G1 cell cycle arrest and apoptosis compared with PTX alone. We concluded that the CD138?CD34? phenotype cells might be CSCs in RPMI 8226 and NCI-H929 cell lines. PTX-NPs had an obvious inhibitory effect on MM CD138?CD34? CSCs. The findings may provide a guideline for PTX-NPs’ treatment of MM CSCs in preclinical investigation

2013-08-01

248

Magnetic, fluorescent, and thermo-responsive Fe(3)O(4)/rare earth incorporated poly(St-NIPAM) core-shell colloidal nanoparticles in multimodal optical/magnetic resonance imaging probes.  

Science.gov (United States)

Multifunctional colloidal nanoparticles which exhibit fluorescence, superparamagnetism, and thermosensitivity are produced by two step seed emulsifier-free emulsion polymerization in the presence of oleic acid (OA) and sodium undecylenate (NaUA) modified Fe(3)O(4) nanoparticles. In the first step, St and NIPAM polymerize the NaUA on the surface of Fe(3)O(4) nanoparticles to form Fe(3)O(4)/poly(St-NIPAM) nanoparticles which act as seeds for the polymerization of Eu(AA)(3)Phen with the remaining St and NIPAM in the second step to form an outer fluorescent layer. The core-shell composite nanoparticles show reversible dimensional changes in response to external temperature stimuli. Fluorescence spectra acquired from the composites exhibit characteristic emission peaks of Eu(3+) at 594 and 619 nm and vivid red luminescence can be observed by 2-photon confocal scanning laser microscopy (CLSM). In vitro cytotoxicity tests based on the MTT assay demonstrate good cytocompatibility and the composites also possess paramagnetic properties with a maximum saturation magnetization of 6.45 emu/g and high transverse relaxivity rates (r(2)) of 411.78 mM(-1) s(-1). In vivo magnetic resonance imaging (MRI) studies show significant liver and spleen contrast with relative signal intensity reduction of about 86% 10 min after intravenous injection of the composites. These intriguing properties suggest that these nanocarriers have large clinical potential as multimodal optical/MRI probes. PMID:23274069

Zhu, Haie; Tao, Juan; Wang, Wenhao; Zhou, Yingjie; Li, Penghui; Li, Zheng; Yan, Kai; Wu, Shuilin; Yeung, Kelvin W K; Xu, Zushun; Xu, Haibo; Chu, Paul K

2013-03-01

249

Mixed hemimicelles solid-phase extraction based on ionic liquid-coated Fe3O4/SiO2 nanoparticles for the determination of flavonoids in bio-matrix samples coupled with high performance liquid chromatography.  

Science.gov (United States)

A novel magnetic solid-phase extraction (MSPE) method based on mixed hemimicelles of room temperature ionic liquids (RTILs) coated Fe3O4/SiO2 nanoparticles (NPs) was developed for simultaneous extraction of trace amounts of flavonoids in bio-matrix samples. A comparative study on the use of RTILs (C16mimBr) and CTAB-coated Fe3O4/SiO2 NPs as sorbents was presented. Owing to bigger adsorption amounts for analytes, RTILs-coated Fe3O4/SiO2 NPs was selected as MSPE materials and three analytes luteolin, quercetin and kaempferol can be quantitatively extracted and simultaneously determined coupled with high performance liquid chromatography (HPLC) in urine samples. No interferences were caused by proteins or endogenous compounds. Good linearity (R(2)>0.9993) for all calibration curves was obtained, and the limits of detection (LOD) for luteolin, quercetin and kaempferol were 0.10 ng/mL, 0.50 ng/mL and 0.20 ng/mL in urine samples, respectively. Satisfactory recoveries (93.5-97.6%, 90.1-95.4% and 93.3-96.6% for luteolin, quercetin and kaempferol) in biological matrices were achieved. It was notable that while using a small amount of Fe3O4/SiO2 NPs (4.0 mg) and C16mimBr (1.0 mg), satisfactory preconcentration factors and extraction recoveries for the three flavonoids were obtained. To the best of our knowledge, this is the first time a mixed hemimicelles MSPE method based on RTILs and Fe3O4/SiO2 NPs magnetic separation has ever been used for pretreatment of complex biological samples. PMID:24290172

He, Huan; Yuan, Danhua; Gao, Zhanqi; Xiao, Deli; He, Hua; Dai, Hao; Peng, Jun; Li, Nan

2014-01-10

250

Inhibition of choriocarcinoma by Fe3O4-dextran-anti-ß-human chorionic gonadotropin nanoparticles containing antisense oligodeoxynucleotide of heparanase  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Liu Huining,1 Zhang Yi,1 Tang Dihong,2 Pan Yifeng,3 Xia Man,2 Yang Ting,2 Cai Jingting1,2 1Department of Obstetrics and Gynecology, Xiangya Hospital, 2Department of Gynecological Oncology, Hunan Provincial Tumor Hospital, 3National Hepatobiliary and Enteric Surgery Research Center, Central South University, Changsha, Hunan, People's Republic of China Objective: To observe the influence of Fe3O4-dextran-anti-ß-human chorionic gonadotropin (HCG) carrying heparanase (Hpa) antisense oli...

2013-01-01

251

Synthesis and characterization of sintering-resistant silica-encapsulated Fe3O4 magnetic nanoparticles active for oxidation and chemical looping combustion  

International Nuclear Information System (INIS)

A nanocomposite catalyst composed of ferromagnetic magnetite cores (15.5 ± 2.0 nm) and silica shells with a thickness of 4.5 ± 1.0 nm (Fe3O4-SiO2) was prepared by a two-step microemulsion-based synthesis. X-ray photoelectron spectroscopy and Raman spectroscopy after oxidation support the presence of a stable Fe3O4 core and a surface phase of ?-Fe2O3. The nanocomposite structure exhibited 100% conversion of CO in oxygen at a residence time of 0.1 s at 310 deg. C. When pre-oxidized, the Fe3O4-SiO2 catalyst is shown to be a suitable solid oxygen carrier for chemical looping combustion of methane at 700 deg. C. The nanocomposites retain their magnetism following the reaction which provides the potential for use of magnetic separation and capture in moving bed reactor applications. The core magnetite within the silica shell is resistant to sintering and a bulk phase transition to temperatures as high as 700 deg. C. These catalysts can be of use in applications of high temperature applications where catalyst recovery by magnetic separation may be required.

2010-06-04

252

Size-controlled synthesis of Fe2O3 and Fe3O4 nanoparticles onto zeolite by means of a modified activated-coprecipitation method: effect of the HCl concentration during the activation  

International Nuclear Information System (INIS)

Synthetic sodium type A zeolite bearing Fe2O3 and Fe3O4 nanoparticles composites have been prepared by means of a coprecipitation method with two different activation methodologies, one using Sn and the other using Sn/Pd nanoparticles as activators. Sn activation generates hematite nanoparticles while Sn/Pd produces magnetite nanoparticles. Amount of HCl used during the activation of the zeolite with SnCl2 showed a correlation between the stannous activating species and the particle size. Both Sn and Sn–Pd activated nanocomposites show nearly narrow size distributions but only those iron oxides obtained with Sn–Pd showed supermagnetism.

2012-11-01

253

Silica-coated iron-oxide nanoparticles synthesized as a T2 contrast agent for magnetic resonance imaging by using the reverse micelle method  

International Nuclear Information System (INIS)

We synthesized iron-oxide (Fe3O4) nanoparticles by using the reverse micelle method and coated them with biocompatible silica. The coated nanoparticles were found to be spherical in the TEM images and showed a uniform size distribution with an average diameter of 10 nm. The T1 and the T2 relaxation times of hydrogen protons in aqueous solutions with various concentrations of silica-coated nanoparticles were determined by using a magnetic resonance (MR) scanner. We found that the T2 relaxivity was much larger than the T1 relaxivity for the nanoparticle contrast agent, which reflected the fact that the T2 relaxation was mainly influenced by outer sphere processes. The T2 relaxivity was found to be 15 times larger than that for the commercial Gd-DTPA-BMA contrast agent. This result demonstrates that silica-coated iron oxide nanoparticles are applicable as a T2 agent in magnetic resonance imaging.

2010-12-01

254

Age Modulates Fe3O4 Nanoparticles Liver Toxicity: Dose-Dependent Decrease in Mitochondrial Respiratory Chain Complexes Activities and Coupling in Middle-Aged as Compared to Young Rats  

Science.gov (United States)

We examined the effects of iron oxide nanoparticles (IONPs) on mitochondrial respiratory chain complexes activities and mitochondrial coupling in young (3 months) and middle-aged (18 months) rat liver, organ largely involved in body iron detoxification. Isolated liver mitochondria were extracted using differential centrifugations. Maximal oxidative capacities (Vmax, complexes I, III, and IV activities), Vsucc (complexes II, III, and IV activities), and Vtmpd, (complex IV activity), together with mitochondrial coupling (Vmax/V0) were determined in controls conditions and after exposure to 250, 300, and 350??g/ml Fe3O4 in young and middle-aged rats. In young liver mitochondria, exposure to IONPs did not alter mitochondrial function. In contrast, IONPs dose-dependently impaired all complexes of the mitochondrial respiratory chain in middle-aged rat liver: Vmax (from 30 ± 1.6 to 17.9 ± 1.5; P Fe3O4 350 µg/ml. Mitochondrial coupling also decreased. Interestingly, 350??g/ml Fe3O4 in the form of Fe3+ solution did not impair liver mitochondrial function in middle-aged rats. Thus, IONPs showed a specific toxicity in middle-aged rats suggesting caution when using it in old age.

Baratli, Yosra; Charles, Anne-Laure; Wolff, Valerie; Ben Tahar, Lotfi; Smiri, Leila; Bouitbir, Jamal; Zoll, Joffrey; Sakly, Mohsen; Auger, Cyril; Vogel, Thomas; Abdelmelek, Hafedh; Geny, Bernard

2014-01-01

255

The sandwich-type electrochemiluminescence immunosensor for ?-fetoprotein based on enrichment by Fe3O4-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP.  

Science.gov (United States)

A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of ?-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe(3)O(4)-Au nanoparticles, which was first employed to capture AFP antigens to form Fe(3)O(4)-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe(3)O(4)-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe(3)O(4)-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL(-1) with a detection limit of 0.2 pg mL(-1). The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the amplification of the signal tag, the immunosensor is highly sensitive, which can offer great promise for rapid, simple, selective and cost-effective detection of effective biomonitoring for clinical application. PMID:22975187

Zhou, Hankun; Gan, Ning; Li, Tianhua; Cao, Yuting; Zeng, Saolin; Zheng, Lei; Guo, Zhiyong

2012-10-01

256

Removal of hexavalent chromium ions by Yarrowia lipolytica cells modified with phyto-inspired Fe0/Fe3O4 nanoparticles  

Science.gov (United States)

The removal of hexavalent chromium [Cr (VI)], an important ground water pollutant by phyto-inspired Fe0/Fe3O4 nanocomposite-modified cells of Yarrowia lipolytica (NCIM 3589 and NCIM 3590), was investigated. Electron microscopy and magnetometer studies indicated an effective modification of yeast cell surfaces by the nanocomposites. The effect of pH, temperature, agitation speed, contact time and initial metal ion concentration on the removal of Cr (VI) was determined. The specific uptake values at pH 2.0 were 186.32 ± 3.17 and 137.31 ± 4.53 mg g- 1 for NCIM 3589 and NCIM 3590, respectively, when 1000 mg L- 1 of metal ion concentrations were used. The equilibrium data fitted to Scatchard, Langmuir and linearized Freundlich models suggesting that adsorption played a role in the removal of Cr (VI) ions. The surface modified yeast cells displayed higher values of Langmuir and Scatchard coefficients than the unmodified cells indicating that the former were more efficient in Cr (VI) removal. The enhanced detoxification of Cr (VI) ions by this composite material could be attributed to the reductive power of the Fe0/Fe3O4 nanocomposites as well the yeast cell surface functional groups.

Rao, Ashit; Bankar, Ashok; Kumar, Ameeta Ravi; Gosavi, Suresh; Zinjarde, Smita

2013-03-01

257

Synthesis and characterization of silica coated potassium ferrite nanoparticles  

Science.gov (United States)

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

258

The sandwich-type electrochemiluminescence immunosensor for ?-fetoprotein based on enrichment by Fe3O4-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP  

International Nuclear Information System (INIS)

Highlights: ? Sandwich immunoreaction, testing a large number of samples simultaneously. ? The magnetic separation and enrichment by Fe3O4-Au magnetic nano probes. ? The amplification of detection signal by CdS-Au composite nanoparticles labeled anti-AFP. ? Almost no background signal, which greatly improve the sensitivity of detection. - Abstract: A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of ?-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe3O4-Au nanoparticles, which was first employed to capture AFP antigens to form Fe3O4-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe3O4-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe3O4-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL?1 with a detection limit of 0.2 pg mL?1. The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the amplification of the signal tag, the immunosensor is highly sensitive, which can offer great promise for rapid, simple, selective and cost-effective detection of effective biomonitoring for clinical application.

2012-10-09

259

Polymide/Fe3O4-carbonized Membranes for Gas Separation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Novel functional carbon membranes for gas separation were designed and prepared by incorporating Fe3O4 nanoparticles into carbon membranes precursor polyimide. The assynthesized membranes were characterized by TEM, XRD and VSM. The effects of Fe3O4 addition and the final pyrolysis temperature on the gas permeability were investigated. The results show that Fe3O4 nanoparticles transformed into other phase morphologies are helpful to form the graphite-like layers during the pyrolysis process, w...

Zhao Xuan-ying, Wang Tong-hua

2010-01-01

260

Synthesis and characterization of Fe3O4 magnetic nanofluid  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ferrofluids are colloidal systems composed of single domain of magnetic nanoparticles dispersed in a liquid carrier. In the present work, Fe3O4 magnetic ferrite nanoparticles were synthesized by chemical coprecipitation method, and were coated with oleic acid as surfactant agent. Magnetic properties of nanoparticles in ferrofluids were investigated with the aid of a vibrating sample magnetometer (VSM) at room temperature. Superparamagnetic behavior, characteristic of magnetic nanoparticles, w...

Lopez, Javier A.; Ferney González; Bonilla, Flavio A.; Gustavo Zambrano; Go?mez, Maria E.

2010-01-01

 
 
 
 
261

Magnetic solid phase extraction of mefenamic acid from biological samples based on the formation of mixed hemimicelle aggregates on Fe(3)O(4) nanoparticles prior to its HPLC-UV detection.  

Science.gov (United States)

A novel and sensitive solid phase extraction method based on the adsorption of cetyltrimethylammonium bromide on the surface of Fe3O4 nanoparticles was developed for extraction and preconcentration of ultra-trace amounts of mefenamic acid in biological fluids. The remarkable properties of Fe3O4 nanoparticles including high surface area and strong magnetization were utilized in this SPE procedure so that a high enrichment factor (98) and satisfactory extraction recoveries (92-99%) were obtained using only 50mg of magnetic adsorbent. Furthermore, a fast separation time (about 15min) was achieved for a large sample volume (200mL) avoiding time-consuming column-passing process of conventional SPE. A comprehensive study on the parameters effecting the extraction recovery such of the amount of surfactant, pH value, the amount of Fe3O4 nanoparticles, sample volume, desorption conditions and ionic strength were also presented. Under the optimum conditions, the method was linear in the 0.2-200ngmL(-1) range and good linearity (r(2)>0.9991) was obtained for all calibration curves. The limit of detection was 0.097 and 0.087ngmL(-1) in plasma and urine samples, respectively. The relative standard deviation (RSD %) for 10 and 50ngmL(-1) of the analyte (n=5) were 1.6% and 2.1% in plasma and 1.2% and 1.9% in urine samples, respectively. Finally, the method was successfully applied to the extraction and preconcentration of mefenamic acid in human plasma and urine samples. PMID:24321760

Beiraghi, Asadollah; Pourghazi, Kamyar; Amoli-Diva, Mitra; Razmara, Akbar

2014-01-15

262

Synthesis and characterization of “mulberry”-like Fe3O4/multiwalled carbon nanotube nanocomposites  

International Nuclear Information System (INIS)

Nanocomposites composed of multi-wall carbon nanotubes (MWNTs) and Fe3O4 nanoparticles were fabricated using solvothermal method. Transmission and scanning electron microscopy, energy dispersive spectroscopy, and X-ray powder diffraction measurements confirmed that these mulberry-like Fe3O4 microparticles which were combined with the MWNTs in a random pattern are constructed with tiny nanocrystallites (12 nm in average diameter). The magnetic properties of the Fe3O4/MWNTs nanocomposites were measured using a vibrating sample magnetometer. Results showed that the Fe3O4/MWNTs nanocomposites exhibited superparamagnetism at room temperature and possessed a lower saturation magnetization (around 27.6 emu/g) than that of the pure Fe3O4 nanoparticles (around 33.7 emu/g). The Fe3O4/MWNTs nanocomposites have potential applications in engineering and medicine.

2011-10-01

263

A novel H2O2 biosensor based on Fe3O4–Au magnetic nanoparticles coated horseradish peroxidase and graphene sheets–Nafion film modified screen-printed carbon electrode  

International Nuclear Information System (INIS)

A disposable biosensor for determination of hydrogen peroxide (H2O2) based on Fe3O4–Au magnetic nanoparticles coated horseradish peroxidase (HRP) and graphene sheets (GS)–Nafion film modified screen-printed carbon electrode (SPCE) was fabricated. To construct the H2O2 biosensor, GS–Nafion solution was first dropped onto the surface of SPCE. Subsequently, the biocomposites of Fe3O4–Au magnetic nanoparticles coated HRP were adsorbed on the surface with the aid of an external magnetic field to fabricate the SPCE|GS–Nafion/Fe3O4–Au-HRP electrode. X-ray powder diffractometer (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry(i–t curve) were employed to study the synthesis of GS, the construction processes and electrochemical properties of the biosensor. Under optimized experimental conditions, CV demonstrated that the direct electron transfer (DET) of HRP was realized. The biosensor had an excellent performance in terms of electrocatalytic reduction toward H2O2. The linear response of the biosensor to H2O2 was in the concentration range of 2.0 × 10?5 mol/L to 2.5 × 10?3 mol/L (R = 0.9994) with a detection limit of 1.2 × 10?5 mol/L (S/N = 3). The proposed electrochemical biosensor was sensitive, rapid, disposable with low cost, fewer sample volume, easy preparation and strong anti-interference, which showed great promise for screen-determination of trace H2O2 in real samples

2013-10-30

264

Core-Shell Nanostructure of ?-Fe2O3/Fe3O4: Synthesis and Photocatalysis for Methyl Orange  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fe3O4 nanoparticle was synthesized in the solution involving water and ethanol. Then, ?-Fe2O3 shell was produced in situ on the surface of the Fe3O4 nanoparticle by surface oxidation in molten salts, forming ?-Fe2O3/Fe3O4 core-shell nanostructure. It was showed that the magnetic properties transformed from ferromagnetism to superparamagnetism after the primary Fe3O4 nanoparticles were oxidized. Furthermore, the obtained ?-Fe2O3/Fe3O4 core-shell nanoparticles were used to ...

Yang Tian; Di Wu; Xiao Jia; Binbin Yu; Sihui Zhan

2011-01-01

265

Preparation and characterization of a magneto-polymeric nanocomposite: Fe3O4 nanoparticles in a grafted, cross-linked and plasticized poly(vinyl chloride) matrix  

International Nuclear Information System (INIS)

In this work two kind of materials: (1) grafted, cross-linked and plasticized poly(vinyl chloride) (PVC) 'plastic films' and (2) magnetic plastic films 'magneto-polymeric nanocomposites' were prepared. Precursor solutions or 'plastisols' used to obtain the plastic films were obtained by mixing PVC (emulsion grade) as polymeric matrix, di(2-ethylhexyl)phthalate (DOP) as plasticizer, a thermal stabilizer based in Ca/Zn salts, and a cross-linking agent, 3-mercaptopropyltrimethoxysilane (MTMS) or 3-aminopropyltriethoxysilane (ATES), at several concentrations. Flexible films were obtained from the plastisols using static casting. The stress-strain behavior and the gel content (determined by Soxhlet extraction with boiling THF) of the flexible films were measured in order to evaluate the effect of the cross-linking agent and their content on the degree of cross-linking. The magneto-polymeric nanocomposites were obtained by mixing the optimum composition of the plastisols (analyzed previously) with magnetite (Fe3O4)-based ferrofluid and DOP. Later, flexible films were obtained by static casting of the plastisol/ferrofluid systems. The magnetic films were characterized by the above-mentioned techniques and X-ray diffraction, vibrating sample magnetometry and thermogravimetrical analysis

2008-07-01

266

Preparation and characterization of a magneto-polymeric nanocomposite: Fe 3O 4 nanoparticles in a grafted, cross-linked and plasticized poly(vinyl chloride) matrix  

Science.gov (United States)

In this work two kind of materials: (1) grafted, cross-linked and plasticized poly(vinyl chloride) (PVC) "plastic films" and (2) magnetic plastic films "magneto-polymeric nanocomposites" were prepared. Precursor solutions or "plastisols" used to obtain the plastic films were obtained by mixing PVC (emulsion grade) as polymeric matrix, di(2-ethylhexyl)phthalate (DOP) as plasticizer, a thermal stabilizer based in Ca/Zn salts, and a cross-linking agent, 3-mercaptopropyltrimethoxysilane (MTMS) or 3-aminopropyltriethoxysilane (ATES), at several concentrations. Flexible films were obtained from the plastisols using static casting. The stress-strain behavior and the gel content (determined by Soxhlet extraction with boiling THF) of the flexible films were measured in order to evaluate the effect of the cross-linking agent and their content on the degree of cross-linking. The magneto-polymeric nanocomposites were obtained by mixing the optimum composition of the plastisols (analyzed previously) with magnetite (Fe 3O 4)-based ferrofluid and DOP. Later, flexible films were obtained by static casting of the plastisol/ferrofluid systems. The magnetic films were characterized by the above-mentioned techniques and X-ray diffraction, vibrating sample magnetometry and thermogravimetrical analysis.

Rodríguez-Fernández, Oliverio S.; Rodríguez-Calzadíaz, C. A.; Yáñez-Flores, Isaura G.; Montemayor, Sagrario M.

267

One-step synthesis of silica-coated magnetite nanoparticles by electrooxidation of iron in sodium silicate solution  

International Nuclear Information System (INIS)

Silica-coated magnetite nanoparticles have been synthesized successfully using a one-step electrochemical method. In this method, pure iron in a dilute aqueous sodium silicate solution that served as a silica precursor was electrooxidized. We show that the presence of silicate can significantly enhance the purity of the magnetite formed. Impurities in the form of FeOOH (found in the magnetite prepared in water) are not found. The magnetite nanoparticles produced by this method are nearly spherical with a mean size ranging from 6 to 10 nm, which is lower than the size of particles prepared in water, and this size range depends on the applied voltage and the sodium silicate concentration. The magnetite nanoparticles exhibit superparamagnetic properties with saturation magnetization ranging from 15 to 22 emu g?1, which is lower than the saturation magnetization of the Fe3O4 bulk materials (Ms = 92 emu g?1). This facile method appears to be promising as a synthetic route for producing silica-coated magnetite nanoparticles.

2012-03-01

268

Confined nanospace pyrolysis for the fabrication of coaxial Fe3O4@C hollow particles with a penetrated mesochannel as a superior anode for Li-ion batteries.  

Science.gov (United States)

In this study, a method is developed to fabricate Fe3O4@C particles with a coaxial and penetrated hollow mesochannel based on the concept of "confined nanospace pyrolysis". The synthesis involves the production of a polydopamine coating followed by a silica coating on a rod-shaped ?-FeOOH nanoparticle, and subsequent treatment by using confined nanospace pyrolysis and silica removal procedures. Typical coaxial hollow Fe3O4@C possesses a rice-grain morphology and mesoporous structure with a large specific surface area, as well as a continuous and flexible carbon shell. Electrochemical tests reveal that the hollow Fe3O4@C with an open-ended nanostructure delivers a high specific capacity (ca. 864 mA h g(-1) at 1 A g(-1)), excellent rate capability with a capacity of about 582 mA h g(-1) at 2 A g(-1), and a high Coulombic efficiency (>97%). The excellent electrochemical performance benefits from the hollow cavity with an inner diameter of 18 nm and a flexible carbon shell that can accommodate the volume change of the Fe3O4 during the lithium insertion/extraction processes as well as the large specific surface area and open inner cavity to facilitate the rapid diffusion of lithium ions from electrolyte to active material. This fabrication strategy can be used to generate a hollow or porous metal oxide structure for high-performance Li-ion batteries. PMID:24273057

Lei, Cheng; Han, Fei; Sun, Qiang; Li, Wen-Cui; Lu, An-Hui

2014-01-01

269

A new route for the synthesis of graphene oxide–Fe3O4 (GO–Fe3O4) nanocomposites and their Schottky diode applications  

International Nuclear Information System (INIS)

Highlights: • Graphene Oxide (GO)–Fe3O4 nanocomposites were prepared by a novel and facile method. • The successful assembly of Fe3O4 NPs onto GO sheets was displayed by TEM. • The GO–Fe3O4 nanocomposites/p-Si junction showed good rectifying property. -- Abstract: Addressed herein is a facile method for the preparation of magnetic graphene oxide–Fe3O4 (GO–Fe3O4) nanocomposites and the rectifying properties of (GO–Fe3O4)/p-Si junction in a Schottky diode. GO–Fe3O4 nanocomposites were prepared by a novel method in which as-prepared GO sheets were decorated with the monodisperse Fe3O4 nanoparticles (NPs) in dimethylformamide/chloroform mixture via a sonication process. The successful assembly of Fe3O4 NPs onto GO sheets was displayed by transmission electron microscopy (TEM). Inductively couple plasma optical emission spectroscopy (ICP-OES) analysis of the GO–Fe3O4 nanocomposite showed that the nanocomposite consists of 20.1 wt% Fe3O4 NPs which provides a specific saturation magnetization (Ms) as 16 emu/g. The current–voltage (I–V) characteristics of the (GO–Fe3O4)/p-Si junction in a Schottky diode were studied in the temperature range of 50–350 K in the steps of 25 K. It was determined that the barrier height and ideality factor of the Au/GO–Fe3O4/p-Si/Al Schottky diode were depended on temperature as the barrier height increased while the ideality factor decreased with increasing temperature. The experimental values of barrier height and ideality factor were varied from 0.12 eV and 11.24 at 50 K to 0.76 eV and 2.49 at 350 K, respectively. The Richardson plot exhibited non-linearity at low temperatures that was attributed to the barrier inhomogeneities prevailing at the GO–Fe3O4/p-Si junction

2014-02-05

270

Maximizing surface-enhanced Raman scattering sensitivity of surfactant-free Ag-Fe3O4 nanocomposites through optimization of silver nanoparticle density and magnetic self-assembly  

Science.gov (United States)

Magnetic composite nanomaterials consisting of more than two functional constituents have been attracting much research interests due to the realization of multiple functionalities in a single entity. In particular, integration of ferromagnetic oxides and noble metal nanoparticles (NPs) in composites results in simultaneous magnetic activity and optical response where the optical property of the whole system could be modulated by application of an external magnetic field. In this work, we prepared Ag NPs-coated Fe3O4 microspheres as a novel surfactant-free surface-enhanced Raman scattering (SERS) substrate through a solid-phase thermal decomposition reaction. The SERS sensitivity of the fabricated nanocomposites is maximized by adjusting the size and density of Ag NPs supported on the Fe3O4 microspheres and further increased by magnetic-field-directed self-assembly of the composite substrates, with both effects attributed to the efficient generation of plasmonic near-field ``hot'' spots. At the optimal conditions, the prepared substrate is capable of detecting rhodamine 6G molecules at a concentration down to 10-12 M, thus demonstrating the great potential of using bifunctional nanocomposites as an excellent candidate for ultra-high sensitive Raman spectroscopy and biosensors. We also reveal the underlying mechanisms responsible for the observed SERS enhancements through full-wave numerical simulations.

Bao, Zhi Yong; Dai, Jiyan; Yuan Lei, Dang; Wu, Yucheng

2013-09-01

271

Magnetoresistance of Fe3O4-graphene-Fe3O4 junctions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The magnetoresistance (MR) of Fe3O4-graphene-Fe3O4 junctions has been experimentally studied at different temperatures. It is found that a barrier exists at the Fe3O4/graphene interface. The existence of the interfacial barrier was further confirmed by the nonlinear I-V characteristics and nonmetallic temperature dependence of the interfacial resistance. Moreover, spin dependent transport at the interfaces contributes ?1.6% MR to the whole device at room temperature and can be regulated by ...

Shvets, Igor; Cross, Graham; Duesberg, Georg Stefan; Wang, Jing Jing

2011-01-01

272

Magnetic biodegradable Fe3O4/CS/PVA nanofibrous membranes for bone regeneration  

International Nuclear Information System (INIS)

In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe3O4/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe3O4 nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe3O4 nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe3O4/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe3O4, CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe3O4 loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe3O4 nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe3O4 nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe3O4 nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe3O4/CS/PVA nanofibrous membranes can be one of promising biomaterials for facilitation of osteogenesis.

2011-10-01

273

Controlled synthesis of porous Fe3O4-decorated graphene with extraordinary electromagnetic wave absorption properties  

International Nuclear Information System (INIS)

Graphical abstract: -- Abstract: Porous Fe3O4-decorated graphene (GN–Fe3O4) composites with different microstructures were successfully synthesized by a modified two-step method. The microstructure and morphology were confirmed by X-ray diffraction (XRD), transmission electron microscopy and scanning electron microscopy. XRD studies show that the products consist of highly crystallized Fe3O4 but disorderedly stacked GN sheets. Electron microscopy images reveal that Fe3O4 nanoparticles with different sizes and microstructures are uniformly coated on both sides of GN sheets, without large vacancies or apparent aggregation. Electromagnetic wave absorption properties of epoxy containing 30 wt.% GN–Fe3O4 composites were investigated at room temperature in the frequency range of 0.5–18 GHz. In particular, the porous, flower-like Fe3O4-decorated GN sample exhibits an enhanced dielectric loss due to the porous microstructure of Fe3O4. The multiple absorbing mechanisms attribute to the improved impedance matching which indicates the as-prepared porous GN–Fe3O4 composites could be a potential candidate for lightweight electromagnetic wave absorption materials

2013-09-01

274

Self-assembled Fe3O4 nanoparticle clusters as high-performance anodes for lithium ion batteries via geometric confinement.  

Science.gov (United States)

Although different kinds of metal oxide nanoparticles continue to be proposed as anode materials for lithium ion batteries (LIBs), their cycle life and power density are still not suitable for commercial applications. Metal oxide nanoparticles have a large storage capacity, but they suffer from the excessive generation of solid-electrolyte interphase (SEI) on the surface, low electrical conductivity, and mechanical degradation and pulverization resulted from severe volume expansion during cycling. Herein we present the preparation of mesoporous iron oxide nanoparticle clusters (MIONCs) by a bottom-up self-assembly approach and demonstrate that they exhibit excellent cyclic stability and rate capability derived from their three-dimensional mesoporous nanostructure. By controlling the geometric configuration, we can achieve stable interfaces between the electrolyte and active materials, resulting in SEI formation confined on the outer surface of the MIONCs. PMID:23902532

Lee, Soo Hong; Yu, Seung-Ho; Lee, Ji Eun; Jin, Aihua; Lee, Dong Jun; Lee, Nohyun; Jo, Hyungyung; Shin, Kwangsoo; Ahn, Tae-Young; Kim, Young-Woon; Choe, Heeman; Sung, Yung-Eun; Hyeon, Taeghwan

2013-09-11

275

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4) nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized w...

Kalantari, Katayoon; Ahmad, Mansor Bin; Shameli, Kamyar; Khandanlou, Roshanak

2013-01-01

276

Fabrication of fluorescent magnetic Fe3O4@ZnS nanocomposites.  

Science.gov (United States)

A novel Fe3O4@ZnS nanomaterial with fluorescent and superparamagnetic properties has been successfully fabricated via TOPO-TOP synthesis with an additional coordinating component (OAm). The adsorption of OAm on the preformed magnetite nanoparticles, which were prepared in phenyl ether with oleic acid and oleyl amine, played an essential role in directing the structure of the Fe3O4@ZnS composites. The obtained materials were characterized by FTIR, TEM, XRD, X-ray photoelectron spectroscopy (XPS), UV-vis, fluorescence spectrophotometer and VSM. The results indicated that the Fe3O4 nanoparticles were successfully combined with ZnS and the coating of ZnS can be controlled by adjusting the molar ratio of Fe3O4 to ZnS. The saturation magnetization values of Fe3O4, Fe3O4@ZnS (1:2) and Fe3O4@ZnS (1:5) nanoparticles are 57.0 emu g(-1), 44.4 emu g(-1) and 34.2 emu g(-1), respectively at 300 K and the nanocomposites exhibit better fluorescence without evident quenching. The combined magnetic and fluorescent properties endow the nanocomposites with great potential applications in "nano-conveyer-belt" platform technology for drug targeting, bioseparation, diagnostic analysis and so on. PMID:24757979

Liu, Li; Jiang, Wei; Yao, Lei; Yang, Xi-Wen; Chen, Bin-Hua; Wu, Shi-Xi; Li, Feng-Sheng

2014-07-01

277

Hollow Fe3O4 microspheres as anode materials for lithium-ion batteries  

International Nuclear Information System (INIS)

In this study, we proposed a unique method for hollow Fe3O4 microspheres and confirmed their electrochemical properties as anode materials for lithium-ion batteries. Poly(MAA/EGDMA)/Fe3O4 core–shell microspheres were prepared by simple ionic attraction between hydrogel microspheres with negative charge and magnetic Fe3O4 nanoparticles under alkaline conditions. The poly(MAA/EGDMA) core spheres were removed by heat treatment in order to form the hollow structure of Fe3O4 microspheres. Their hollow structure prevents cracking of the electrode during the volume change of repetitive Li-ion insertion and extraction reactions and improves the Li-ion transfer during cycling. The morphologies and structure of the hollow Fe3O4 microspheres were confirmed by scanning electron microscopy, focused ion beam-scanning electron microscopy, transmission electron microscopy, optical microscopy and X-ray diffraction. The electrochemical performance of the composite electrode was evaluated by constant current charging and discharging, cyclic voltammetry and cycling performance at various cycling rates. The results showed excellent cycle stability compared with a composite electrode containing bare Fe3O4 nanoparticles. These results indicate that the unique structures of Fe3O4 microspheres contribute to the excellent life and high reversible capacity of the battery when they are used as an anode of a lithium-ion battery.

2012-07-30

278

Exchange bias effect in Au-Fe3O4 nanocomposites  

Science.gov (United States)

We report exchange bias (EB) effect in the Au-Fe3O4 composite nanoparticle system, where one or more Fe3O4 nanoparticles are attached to an Au seed particle forming ‘dimer’ and ‘cluster’ morphologies, with the clusters showing much stronger EB in comparison with the dimers. The EB effect develops due to the presence of stress at the Au-Fe3O4 interface which leads to the generation of highly disordered, anisotropic surface spins in the Fe3O4 particle. The EB effect is lost with the removal of the interfacial stress. Our atomistic Monte Carlo studies are in excellent agreement with the experimental results. These results show a new path towards tuning EB in nanostructures, namely controllably creating interfacial stress, and opens up the possibility of tuning the anisotropic properties of biocompatible nanoparticles via a controllable exchange coupling mechanism.

Chandra, Sayan; Frey Huls, N. A.; Phan, M. H.; Srinath, S.; Garcia, M. A.; Lee, Youngmin; Wang, Chao; Sun, Shouheng; Iglesias, Òscar; Srikanth, H.

2014-02-01

279

Magnetoresistance of Fe3O4/Au/Fe3O4 and Fe3O4/Au/Fe spin-valve structures  

International Nuclear Information System (INIS)

A detailed study of the in-plane magnetotransport properties of spin valves with one and two Fe3O4 electrodes is presented. Fe3O4/Au/Fe3O4 spin valves exhibit a clear anisotropic magnetoresistance in small magnetic fields but no giant magnetoresistance (GMR). The absence of GMR in these structures is due to simultaneous magnetization reversal in the two Fe3O4 layers. By contrast, a negative GMR effect is measured on Fe3O4/Au/Fe spin valves. The negative GMR is attributed to an electron spin scattering asymmetry at the Fe3O4/Au interface or an induced spin scattering asymmetry in the Au interfacial layers

2004-09-01

280

Heterogeneous Fenton degradation of bisphenol A catalyzed by efficient adsorptive Fe3O 4/GO nanocomposites.  

Science.gov (United States)

A new method for the degradation of bisphenol A (BPA) in aqueous solution was developed. The oxidative degradation characteristics of BPA in a heterogeneous Fenton reaction catalyzed by Fe3O4/graphite oxide (GO) were studied. Transmission electron microscopic images showed that the Fe3O4 nanoparticles were evenly distributed and were ?6 nm in diameter. Experimental results suggested that BPA conversion was affected by several factors, such as the loading amount of Fe3O4/GO, pH, and initial H2O2 concentration. In the system with 1.0 g L(-1) of Fe3O4/GO and 20 mmol L(-1) of H2O2, almost 90 % of BPA (20 mg L(-1)) was degraded within 6 h at pH 6.0. Based on the degradation products identified by GC-MS, the degradation pathways of BPA were proposed. In addition, the reused catalyst Fe3O4/GO still retained its catalytic activity after three cycles, indicating that Fe3O4/GO had good stability and reusability. These results demonstrated that the heterogeneous Fenton reaction catalyzed by Fe3O4/GO is a promising advanced oxidation technology for the treatment of wastewater containing BPA. PMID:24627203

Hua, Zulin; Ma, Wenqiang; Bai, Xue; Feng, Ranran; Yu, Lu; Zhang, Xiaoyuan; Dai, Zhangyan

2014-06-01

 
 
 
 
281

The investigation of electrochemical properties for Fe3O4@Pt nanocomposites and an enhancement sensing for nitrite  

International Nuclear Information System (INIS)

Highlights: •Electrochemical characteristics on nanoparticles and nanocomposites were compared. •The reasons for superior electrochemical activity of Fe3O4@Pt were discussed. •We report an excellent nitrite biosensor based on Fe3O4@Pt. •Electro-analytical parameters of nitrite at Fe3O4@Pt were evaluated in detail. -- Abstract: The electrochemical differences (such as charge transfer resistivity, electroactive surface, standard electron transfer rate constant, adsorption amount and analytical performance of nitrite sensor) between Fe3O4@Pt nanocomposites with two elements and core–shell structure and NPs (Fe3O4 nanoparticles and Pt nanoparticles) with single component and simple structure were investigated in detail. Above those investigations, it is believed that for the Fe3O4@Pt core–shell nanocomposites, Pt shell could provide more electro-catalytic activity while magnetic Fe3O4 core could provide larger surface area and facilitate the purification of nanocomposites. After that, Fe3O4@Pt nanocomposites modified GCE served as a nitrite sensor. Electrochemical parameters of nitrite at Fe3O4@Pt nanocomposites such as electron transfer number, electron transfer coefficient, standard heterogeneous rate constant and electron diffusion coefficient were evaluated. With the proposed electrochemical sensors, nitrite in tap water and orange juice could be detected. This investigation suggested that core–shell nanocomposites were superior for the fabrication of electrochemical sensors

2013-11-30

282

Synthesis and characterization of Fe3O4-C-Ag nanocomposites and their antibacterial performance  

International Nuclear Information System (INIS)

We synthesized Fe3O4-C-Ag nanocomposites through a combination of solvothermal, hydrothermal, and chemical redox reactions. Characterization of the resulting samples by X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning and transmission electron microscopy, and magnetic measurement is reported. Compared to Fe3O4-Ag nanocomposites, the Fe3O4-C-Ag nanocomposites showed enhanced antibacterial activity. The Fe3O4-C-Ag nanocomposites were able to almost entirely prevent growth of Escherichia coli when the concentration of Ag nanoparticles was 10 ?g/mL. Antibacterial activity of the Fe3O4-C-Ag nanocomposites was maintained for more than 40 h at 37 deg. C. The intermediate carbon layer not only protects magnetic core, but also improves the dispersion and antibacterial activity of the silver nanoparticles. The magnetic core can be used to control the specific location of the antibacterial agent (via external magnetic field) and to recycle the residual silver nanoparticles. The Fe3O4-C-Ag nanocomposites will have potential uses in many fields as catalysts, absorbents, and bifunctional magnetic-optical materials.

2011-09-01

283

Nonlinear optical and optical limiting properties of graphene oxide–Fe3O4 hybrid material  

International Nuclear Information System (INIS)

The nonlinear optical (NLO) and optical limiting properties of a graphene oxide hybrid material coordinated with Fe3O4 nanoparticles (GO–Fe3O4) were studied by using the Z-scan technique at 532 nm in the nanosecond and picosecond regimes. Results show that GO–Fe3O4 exhibits enhanced NLO and optical limiting properties in comparison with the pristine GO in the nanosecond regime. Compared with fullerene (C60) in toluene at different concentrations, GO–Fe3O4 exhibits a weaker optical limiting effect than C60 at high concentration, but shows a stronger optical limiting effect than C60 at low concentration in the high input fluence region

2011-07-01

284

Facile synthesis of monodisperse superparamagnetic Fe3O4/PMMA composite nanospheres with high magnetization  

International Nuclear Information System (INIS)

Monodisperse superparamagnetic Fe3O4/polymethyl methacrylate (PMMA) composite nanospheres with high saturation magnetization were successfully prepared by a facile novel miniemulsion polymerization method. The ferrofluid, MMA monomer and surfactants were co-sonicated and emulsified to form stable miniemulsion for polymerization. The samples were characterized by DLS, TEM, FTIR, XRD, TGA and VSM. The diameter of the Fe3O4/PMMA composite nanospheres by DLS was close to 90 nm with corresponding polydispersity index (PDI) as small as 0.099, which indicated that the nanospheres have excellent homogeneity in aqueous medium. The TEM results implied that the Fe3O4/PMMA composite nanospheres had a perfect core-shell structure with about 3 nm thin PMMA shells, and the core was composed of many homogeneous and closely packed Fe3O4 nanoparticles. VSM and TGA showed that the Fe3O4/PMMA composite nanospheres with at least 65% high magnetite content were superparamagnetic, and the saturation magnetization was as high as around 39 emu g-1 (total mass), which was only decreased by 17% compared with the initial bare Fe3O4 nanoparticles.

2011-06-03

285

Structural and functional investigation of graphene oxide-Fe3O4 nanocomposites for the heterogeneous Fenton-like reaction  

Science.gov (United States)

Graphene oxide–iron oxide (GO–Fe3O4) nanocomposites were synthesised by co-precipitating iron salts onto GO sheets in basic solution. The results showed that formation of two distinct structures was dependent upon the GO loading. The first structure corresponds to a low GO loading up to 10?wt%, associated with the beneficial intercalation of GO within Fe3O4 nanoparticles and resulting in higher surface area up to 409?m2 g?1. High GO loading beyond 10?wt% led to the aggregation of Fe3O4 nanoparticles and the undesirable stacking of GO sheets. The presence of strong interfacial interactions (Fe-O-C bonds) between both components at low GO loading lead to 20% higher degradation of Acid Orange 7 than the Fe3O4 nanoparticles in heterogeneous Fenton-like reaction. This behaviour was attributed to synergistic structural and functional effect of the combined GO and Fe3O4 nanoparticles.

Zubir, Nor Aida; Yacou, Christelle; Motuzas, Julius; Zhang, Xiwang; Diniz da Costa, Joao C.

2014-01-01

286

Structural and functional investigation of graphene oxide–Fe3O4 nanocomposites for the heterogeneous Fenton-like reaction  

Science.gov (United States)

Graphene oxide-iron oxide (GO-Fe3O4) nanocomposites were synthesised by co-precipitating iron salts onto GO sheets in basic solution. The results showed that formation of two distinct structures was dependent upon the GO loading. The first structure corresponds to a low GO loading up to 10 wt%, associated with the beneficial intercalation of GO within Fe3O4 nanoparticles and resulting in higher surface area up to 409 m2 g-1. High GO loading beyond 10 wt% led to the aggregation of Fe3O4 nanoparticles and the undesirable stacking of GO sheets. The presence of strong interfacial interactions (Fe-O-C bonds) between both components at low GO loading lead to 20% higher degradation of Acid Orange 7 than the Fe3O4 nanoparticles in heterogeneous Fenton-like reaction. This behaviour was attributed to synergistic structural and functional effect of the combined GO and Fe3O4 nanoparticles.

Zubir, Nor Aida; Yacou, Christelle; Motuzas, Julius; Zhang, Xiwang; Diniz da Costa, João C.

2014-04-01

287

Synthesis and characterization of Fe3O4 magnetic nanofluid  

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Full Text Available Ferrofluids are colloidal systems composed of single domain of magnetic nanoparticles dispersed in a liquid carrier. In the present work, Fe3O4 magnetic ferrite nanoparticles were synthesized by chemical coprecipitation method, and were coated with oleic acid as surfactant agent. Magnetic properties of nanoparticles in ferrofluids were investigated with the aid of a vibrating sample magnetometer (VSM at room temperature. Superparamagnetic behavior, characteristic of magnetic nanoparticles, was determined from the hysteresis loop of M vs. H measurements. The sample as powder was characterized by means of X-ray diffraction. XRD pattern result shows the presence of the most intense peak corresponds to the (311 crystallographic orientation of the spinel phase of Fe3O4 magnetic nanoparticles. The mean size of the nanoparticles was determined from the X-ray diffraction pattern by using the Scherrer approximation. The particle size was calculated to be 9.64 nm. Atomic Force Microscopy was used to visualize the morphology of nanoparticles and to measure their diameter. The AFM method showed an average nanoparticles diameter of D N = 15.3 nm. FTIR absorption spectroscopy was used to confirm the formation of Fe-O bonds, allowing to identify the inverse ferrites spinel structure, as well as, the presence of other chemical substances adsorbed on the surface of particles.Los ferrofluidos son sistemas coloidales compuestos de nanopartículas magnéticas con mono-dominios magnéticos, dispersas en un líquido portador. En el presente trabajo, nanopartículas magnéticas de ferrita (Fe3O4 se sintetizaron por el método de co-precipitación química, y se recubrieron con ácido oleico como agente surfactante. Las propiedades magnéticas de las nanopartículas en el ferrofluido fueron investigadas por medio de un magnetómetro de muestra vibrante (VSM a temperatura ambiente, mostrando un comportamiento superparamagnético, característico de estas nanopartículas magnéticas. Esto se determinó a partir de la curva de histéresis de M vs H. La muestra en polvo se caracterizó por medio de Difracción de Rayos X. El patrón DRX resultante muestra la presencia del pico más intenso correspondiente a la orientación cristalográfica (311 de la fase espinel para las nanopartículas magnéticas de Fe3O4. El tamaño medio de las nanopartículas se determinó a partir del patrón de difracción de rayos X utilizando la aproximación de Scherrer, siendo este tamaño medio de 9,64 nm. La microscopía de fuerza atómica, se utilizó para visualizar la morfología de las nanopartículas y para determinar su diámetro. Las medidas de AFM muestran un diámetro promedio para las nanopartículas de D N = 15,3 nm La espectroscopia de absorción FTIR se utilizó para confirmar la formación de los enlaces Fe-O, permitiendo identificar la estructura tipo espinela de la ferrita, así como la presencia de otras sustancias químicas adsorbidas en la superficie de las partículas.

Javier A Lopez

2010-06-01

288

Architecture of Fe3O4–graphene oxide nanocomposite and its application as a platform for amino acid biosensing  

International Nuclear Information System (INIS)

Highlights: ? Fe3O4–GO nanocomposites are prepared. ? Fe3O4–GO exhibits high catalysis towards the oxidation of cysteine and N-acetyl cysteine. ? Mediating Fe3O4–GO on a glassy carbon electrode developed an electrochemical sensor. ? The sensor showed high selectivity and stability. - Abstract: The Fe3O4–graphene oxide (Fe3O4–GO) nanocomposites were prepared by a chemical co-precipitation of FeSO4, FeCl3,·NH3·H2O and GO. The Fe3O4–GO was characterized by scanning electron microscopy, X-ray powder diffraction, thermogravimetric analysis and electrochemical method. The results showed that ultrafine Fe3O4 nanoparticles was prepared and densely assembled on GO nanosheets. The Fe3O4–GO exhibits large surface area and high catalysis towards the oxidation of cysteine and N-acetyl cysteine, which could be used for cysteine and N-acetyl cysteine sensing with a wide linear range (0.5–13.5 mM for cysteine and 0.12–13.3 mM for N-acetyl cysteine) and low detection limit (56 ?M for cysteine and 25 ?M for N-acetyl cysteine). The excellent catalytic activity, high sensitivity and good stability made such Fe3O4–GO nanocomposites to be promising nanomaterials for constructing nonenzymatic sensor.

2012-06-01

289

Fe3O4/reduced graphene oxide nanocomposite as high performance anode for lithium ion batteries  

International Nuclear Information System (INIS)

Highlights: ? Fe3O4/graphene composite is fabricated by interface reaction and in situ reduction. ? The method leads to well-organized flexible interleaved structure. ? The interface reaction is benefit to ensure strong interfacial interaction. ? The nanocomposite shows high reversible capacity and super long cycling stability - Abstract: Fe3O4/reduced graphene oxide (Fe3O4/RGO) nanocomposite was prepared by a facile interface reaction and subsequent in situ reduction process. The electrochemical performances of the as-prepared Fe3O4/RGO nanocomposite were evaluated in coin-type cells. It delivers high reversible capacity of 1025 mAh g?1 at 100 mA g?1 after 50 cycles and outstanding cycle stability. Even after 800 cycles at various rates from 100 to 4000 mA g?1, the capacity still retains 959.4 mAh g?1 at 100 mA g?1. A transmission electron microscopy image has shown the flexible interleaved structure of nanocomposite, and the interface reaction is also benefit to ensure strong interfacial interaction between Fe3O4 nanoparticles (50 nm) and RGO nanosheets. The designed structure plays key role in improving electrochemical performance. The Fe3O4/RGO nanocomposite with super long cycling life will be an ideal candidate of anode material for lithium ion batteries.

2012-11-15

290

Fabrication and estimation of Au-coated Fe3O4 nanocomposite powders for the separation and purification of biomolecules  

International Nuclear Information System (INIS)

Au and Fe3O4 nanoparticles were prepared by reduction and coprecipitation methods. The Au/Fe3O4 nanocomposite particles were prepared through the control of the surface charges, and glutathione (GSH) of a thiol group was used as a biomolecule. GSH immobilization onto Au/Fe3O4 was accomplished by simply mixing process. The nanoparticles were characterized by UV-vis spectroscopy: X-ray diffraction, transmission electron microscopy and vibrating sample magnetometry. The amount of immobilized GSH on the Au/Fe3O4 increased with increasing amount of coated Au nanoparticles. The possibility of Au/Fe3O4 nanocomposite particles for the application to the separation and purification of biomolecules by magnetic field was confirmed

2007-03-25

291

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method.  

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The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe(3)O(4)) nanoparticles on talc layers using an environmentally friendly process. The Fe(3)O(4) magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe(3)O(4) precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94-0.93 nm); therefore, Fe(3)O(4) nanoparticles formed on the exterior surface of talc, with an average size of 1.95-2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe(3)O(4) nanocomposites may have potential applications in the chemical and biological industries. PMID:23696700

Kalantari, Katayoon; Bin Ahmad, Mansor; Shameli, Kamyar; Khandanlou, Roshanak

2013-01-01

292

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method  

Science.gov (United States)

The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4) nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94?0.93 nm); therefore, Fe3O4 nanoparticles formed on the exterior surface of talc, with an average size of 1.95–2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe3O4 nanocomposites may have potential applications in the chemical and biological industries.

Kalantari, Katayoon; Ahmad, Mansor Bin; Shameli, Kamyar; Khandanlou, Roshanak

2013-01-01

293

A dual mode targeting probe for distinguishing HER2-positive breast cancer cells using silica-coated fluorescent magnetic nanoparticles  

International Nuclear Information System (INIS)

We report a composite nanoprobe based on silica-coated magnetic nanoparticles (NPs) for distinguishing breast cancers at different HER2 statuses. The nanoprobe has a core–shell structure, with Fe3O4 NPs as the magnetic core and dye-embedded silica as the fluorescent shell, whose average size is about 150 nm. Besides, the outmost surfaces of the probes were modified with specific antibodies to endow the probe with a targeting ability. With such a structure, the nanoprobe can accomplish dual mode targeting of human breast cancer cells based on fluorescence and magnetic resonance imaging (MRI). In the experiments, three human breast cancer cell lines were used to test the targeting ability of the nanoprobe. Specifically, SKBR3 cells with a high HER2 expression level were used as the model target cells, while MCF7 cells with a lower HER2 expression levels and HER2-negative MDA-MB-231 cells were used as the controls. Both the fluorescence and MRI imaging results confirmed that the nanoprobe can distinguish three cancer cell lines with different HER2 expression levels. With the dual mode imaging and specific targeting properties, we anticipate that the presented nanoprobe may have a great potential in the diagnosis and treatment of cancerous diseases

2013-10-01

294

Mössbauer evidence of 57Fe3O4 based ferrofluid biodegradation in the brain  

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The ferrofluid, based on 57Fe isotope enriched Fe3O4 nanoparticles, was synthesized, investigated by Mössbauer spectroscopy method and injected transcranially in the ventricle of the rat brain. The comparison of the Mössbauer spectra of the initial ferrofluid and the rat brain measured in two hours and one week after the transcranial injection allows us to state that the synthesized magnetic 57Fe3O4 nanoparticles undergo intensive biodegradation in live brain and, therefore, they can be regarded as a promising target for a new method of radionuclide-free Mössbauer brachytherapy.

Polikarpov, D.; Cherepanov, V.; Chuev, M.; Gabbasov, R.; Mischenko, I.; Nikitin, M.; Vereshagin, Y.; Yurenia, A.; Panchenko, V.

2014-04-01

295

Polymide/Fe3O4-carbonized Membranes for Gas Separation  

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Full Text Available Novel functional carbon membranes for gas separation were designed and prepared by incorporating Fe3O4 nanoparticles into carbon membranes precursor polyimide. The assynthesized membranes were characterized by TEM, XRD and VSM. The effects of Fe3O4 addition and the final pyrolysis temperature on the gas permeability were investigated. The results show that Fe3O4 nanoparticles transformed into other phase morphologies are helpful to form the graphite-like layers during the pyrolysis process, which make the membrane with two types of carbon structure : amorphous carbon and graphite-like layers. All the functional carbon membranes exhibit magnetism. Single gas permeation test results show that the assynthesized membranes exhibit an outstanding molecular sieving capability together with high gas permeability. The gas permeability of H2 is 61 times higher than the pure carbon membrane and the H2/CO2 selectivity is also improved. Fe3O4 addition and the final pyrolysis temperature siginificantly impair the gas permeability. When the Fe3O4 content is 20wt%, the permeabilities of pure gas H2, CO2, O2, N2, CH4 in the functional carbon membrane are 15476, 4385, 1565, 193 and 114 Barrers (1Barrer=1×10-10 cm3 (STP ·cm/(cm2·s·cmHg, respecticvely. The final pyrolysis temperature also has a remarkable effect on the gas separation performance.

ZHAO Xuan-Ying,WANG Tong-Hua,LI Lin,LIU Ying,CAO Yi-Ming

2010-07-01

296

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method  

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Full Text Available Katayoon Kalantari,1 Mansor Bin Ahmad,1,* Kamyar Shameli,1,2,* Roshanak Khandanlou11Department of Chemistry, Universiti Putra Malaysia, Serdang, Malaysia; 2Nanotechnology and Advance Materials Department, Materials and Energy Research Center, Karaj, Alborz, Karaj, Iran*These authors contributed equally to this workAbstract: The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4 nanoparticles on talc layers using an environmentally friendly process. The Fe3O4 magnetic nanoparticles were synthesized using the chemical co-precipitation method on the exterior surface layer of talc mineral as a solid substrate. Ferric chloride, ferrous chloride, and sodium hydroxide were used as the Fe3O4 precursor and reducing agent in talc. The talc was suspended in deionized water, and then ferrous and ferric ions were added to this solution and stirred. After the absorption of ions on the exterior surface of talc layers, the ions were reduced with sodium hydroxide. The reaction was carried out under a nonoxidizing oxygen-free environment. There were not many changes in the interlamellar space limits (d-spacing = 0.94–0.93 nm; therefore, Fe3O4 nanoparticles formed on the exterior surface of talc, with an average size of 1.95–2.59 nm in diameter. Nanoparticles were characterized using different methods, including powder X-ray diffraction, transmission electron microscopy, emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. These talc/Fe3O4 nanocomposites may have potential applications in the chemical and biological industries.Keywords: nanocomposites, Fe3O4 nanoparticles, talc, powder X-ray diffraction, scanning electron microscopy

Kalantari K

2013-05-01

297

Mössbauer study of a Fe3O4/PMMA nanocomposite synthesized by sonochemistry  

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Magnetite nanoparticles of 10 nm average size were synthesized by ultrasonic waves from the chemical reaction and precipitation of ferrous and ferric iron chloride (FeCl3 · 6H2O y FeCl2 · 4H2O) in a basic medium. The formation and the incorporation of the magnetite in PMMA were followed by XRD and Mössbauer Spectroscopy. These magnetite nanoparticles were subsequently incorporated into the polymer by ultrasonic waves in order to obtain the final sample of 5 % weight Fe3O4 into the polymethylmethacrylate (PMMA). Both samples Fe3O4 nanoparticles and 5 % Fe3O4/PMMA nanocomposite, were studied by Mössbauer spectroscopy in the temperature range of 300 K-77 K. In the case of room temperature, the Mössbauer spectrum of the Fe3O4 nanoparticles sample was fitted with two magnetic histograms, one corresponding to the tetrahedral sites (Fe3 + ) and the other to the octahedral sites (Fe3 + and Fe2 + ), while the 5 % Fe3O4/PMMA sample was fitted with two histograms as before and a singlet subspectrum related to a superparamagnetic behavior, caused by the dispersion of the nanoparticles into the polymer. The 77 K Mössabuer spectra for both samples were fitted with five magnetic subspectra similar to the bulk magnetite and for the 5 % Fe3O4/PMMA sample it was needed to add also a superparamagnetic singlet. Additionally, a study of the Verwey transition has been done and it was observed a different behavior compared with that of bulk magnetite.

Martínez, H.; D'Onofrio, L.; González, G.

2014-01-01

298

Green synthesis and surface properties of Fe3O4@SA core–shell nanocomposites  

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In this paper, a one-step, economic and green approach was explored to prepare Fe3O4 nanoparticles by using L-cysteine as reducer and disperser without any inert gas protection. The Fe3O4 nanoparticles were then modified with stearic acid (SA) to form Fe3O4@SA core–shell nanocomposites. The experiment results indicate that the core–shell nanocomposites prepared could form monolayer on the water surface or films by means of Langmuir–Blodgett (LB) technology due to their hydrophobic and lipophilic properties. Also the composites exhibit paramagnetism, which make product dispersed stably in the oil medium to form magnetic fluid. Moreover, they are developed as sorbents to remove oil from water surface.

Cao, Huimin; Li, Juchuan; Shen, Yuhua; Li, Shikuo; Huang, Fangzhi; Xie, Anjian

2014-05-01

299

Structure and electrochemical performance of nanostructured Fe3O4/carbon nanotube composites as anodes for lithium ion batteries  

International Nuclear Information System (INIS)

Polyvinyl alcohol (PVA) was used as a hydrogen bond functionalizing agent to modify multi-walled carbon nanotubes (CNTs). Nanoparticles of Fe3O4 were then formed along the sidewalls of the as-modified CNTs by the chemical coprecipitation of Fe2+ and Fe3+ in the presence of CNTs in an alkaline solution. The structure and electrochemical performance of the Fe3O4/CNTs nanocomposite electrodes have been investigated in detail. Electrochemical tests indicated that at the 145th cycle, the CNTs-66.7 wt.%Fe3O4 nanocomposite electrode can deliver a high discharge capacity of 656 mAh g-1 and stable cyclic retention. The improvement of reversible capacity and cyclic performance of the Fe3O4/CNTs nanocomposite could be attributed to the nanosized Fe3O4 particles and the network of CNTs.

2010-01-01

300

Low-temperature hydrothermal synthesis of ?-Fe/Fe3O4 nanocomposite for fast Congo red removal.  

Science.gov (United States)

A facile low-temperature hydrothermal process to synthesize ?-Fe/Fe(3)O(4) nanocomposite is reported. TEM and HRTEM revealed that the ?-Fe/Fe(3)O(4) nanocomposite was composed of catenulate ?-Fe and lamellar structured Fe(3)O(4). The weight ratio of ?-Fe in the ?-Fe/Fe(3)O(4) nanocomposite is 35.6%. The ?-Fe/Fe(3)O(4) nanocomposite demonstrates an extremely high Congo red (CR) removal efficiency from waste water showing almost complete removal within 3 min. For 100 mg L(-1) of CR aqueous solution, the maximum CR removal can reach 1297.06 mg g(-1). The large saturation magnetization (80.5 emu g(-1)) of the nanocomposite allows fast separation of ?-Fe/Fe(3)O(4) nanoparticles loaded with CR from the liquid suspension. The synergistic effect of the nanocomposite may contribute to the enhanced CR removal ability, because the CR can be removed by reduction reaction and adsorption at the same time. Based on the degradation products identified by UV-Vis spectra, XRD and FTIR spectra, a possible degradation mechanism of CR on the ?-Fe/Fe(3)O(4) composite was proposed. The significantly reduced treatment time required to remove the CR and the simple, low-cost and pollution-free preparation method make ?-Fe/Fe(3)O(4) nanocomposite promising for highly efficient removal of dyes from waste water. PMID:23223415

Wang, Lixia; Li, Jianchen; Wang, Zhitao; Zhao, Lijun; Jiang, Qing

2013-02-21

 
 
 
 
301

Facile and straightforward synthesis of superparamagnetic reduced graphene oxide–Fe3O4 hybrid composite by a solvothermal reaction  

International Nuclear Information System (INIS)

A superparamagnetic reduced graphene oxide–Fe3O4 hybrid composite (rGO–Fe3O4) was prepared via a facile and straightforward method through the solvothermal reaction of iron (III) acetylacetonate (Fe(acac)3) and graphene oxide (GO) in ethylenediamine (EDA) and water. By this method, chemical reduction of GO as well as the formation of Fe3O4 nanoparticles (NPs) can be achieved in one step. The Fe3O4 NPs are firmly deposited on the surfaces of rGO, avoiding their reassembly to graphite. The rGO sheets prevent the agglomeration of Fe3O4 NPs and enable a uniform dispersion of these metal oxide particles. The size distribution and coverage density of Fe3O4 NPs deposited on rGO can be controlled by varying the initial mass ratio of GO and iron precursor, Fe(acac)3. With an initial mass ratio of GO and Fe(acac)3 of 5:5, the surfaces of rGO sheets are densely covered by spherical Fe3O4 NPs with an average size of 19.9 nm. The magnetic-functionalized rGO hybrid exhibits a good magnetic property and the specific saturation magnetization (Ms) is 13.2 emu g?1. The adsorption test of methylene blue from aqueous solution demonstrates the potential application of this rGO-Fe3O4 hybrid composite in removing organic dyes from polluted water. (paper)

2013-01-18

302

Optimization of oleylamine-Fe3O4/MWCNTs nanocomposite modified GC electrode for electrochemical determination of ofloxacin.  

Science.gov (United States)

Iron oxide (Fe3O4) nanoparticles are prepared by nucleation method using oleylamine (OLA) as the capping agent. The OLA capped Fe3O4 nanoparticles (OLA-Fe3O4) are characterized by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD) and High Resolution Transmission Electron Microscopic (HRTEM) analysis. The morphology of the OLA-Fe3O4 nanoparticles is found to be spherical with an average size of 7.5 +/- 0.5 nm. OLA-Fe3O4 nanoparticles are incorporated into the carboxyl functionalized Multi-walled carbon nanotubes (MWCNTs) at different 10, 20, 30, 40 and 50 wt% by ultrasonication. The optimum loading of OLA-Fe3O4 nanoparticles on the MWCNTs was characterized by FTIR, Raman spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) and Linear Sweep Voltammetry (LSV). Finally, the 40wt% of OLA-Fe3O4 nanoparticles on MWCNTs was chosen as the optimum loading and this composition was used for the electrochemical oxidation of ofloxacin (OFX). For determination of OFX in OLA-Fe3O4/MWCNTs modified glassy carbon (GC) electrode show high sensitivity and fast response. The sensitivity of the modified electrode was calculated to be 0.578 microAmicroM(-1) with a detection limit of 0.060 microM. The high sensitivity, wider linear range, good reproducibility and the minimal surface fouling make this OLA-Fe3O4/MWCNTs/GC modified electrode acts as a promising platform for electrochemical determination of OFX. PMID:24757981

Kumar, Deivasigamani Ranjith; Manoj, Devaraj; Santhanalakshmi, Jayadevan

2014-07-01

303

Hydrothermal synthesis of carbon nanotube/cubic Fe3O4 nanocomposite for enhanced performance supercapacitor electrode material  

International Nuclear Information System (INIS)

Graphical abstract: First, the acid treated CNTs were used as support substrate. Then cubic Fe3O4 nanoparticles directly anchored on the surfaces of CNTs as supercapacitor electrode material by an easy and cost effective hydrothermal method. Results showed that the composite has superior capacitive performance with a maximum specific capacitance of 119 F/g. -- Highlights: • The acid treated CNTs were used as conductive substrate materials. • Cubic Fe3O4 nanoparticles directly grew onto surfaces of CNTs preventing the agglomeration of Fe3O4. • The loose structure improves the contact between the electrode and the electrolyte. • Results showed that this composite has good electrochemical property. -- Abstract: Carbon nanotube/Fe3O4 (CNT/Fe3O4) nanocomposite with well-dispersed Fe3O4 nano-cubes inlaid on the surfaces of carbon nanotubes, was synthesized through an easy and efficient hydrothermal method. The electrochemical behaviors of the nanocomposite were analyzed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronopotentiometry in 6 M KOH electrolyte. Results demonstrated that CNT as the supporting material could significantly improve the supercapacitor (SC) performance of the CNT/Fe3O4 composite. Comparing with pure Fe3O4, the resulting composite exhibited improved specific capacitances of 117.2 F/g at 10 mA/cm2 (3 times than that of pure Fe3O4), excellent cyclic stability and a maximum energy density of 16.2 Wh/kg. The much improved electrochemical performances could be attributed to the good conductivity of CNTs as well as the anchored Fe3O4 particles on the CNTs

2013-06-01

304

Preparation of Fe3O4 with high specific surface area and improved capacitance as a supercapacitor.  

Science.gov (United States)

Here, we report for the first time a facile ultrasonic synthesis of Fe3O4 nanoparticles using FeCl3 and the organic solvent ethanolamine (ETA). The intermediate of the ETA-Fe(II) complex produces Fe3O4 after hydrolysis and hydrothermal treatment. The moderate reduction of ETA and ultrasound play an important role in the synthesis of superfine Fe3O4 particles with a very high specific surface area (165.05 m(2) g(-1)). The Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), high-resolution transmission electron microscopy (HRTEM), and ultraviolet-visible absorption spectroscopy (UV-vis). Fe3O4 as an electrode material was fabricated into a supercapacitor and characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements. The as-synthesized Fe3O4 exhibits remarkable pseudocapacitive activities including high specific capacitance (207.7 F g(-1) at 0.4 A g(-1)), good rate capability (90.4 F g(-1) at 10 A g(-1)), and excellent cycling stability (retention 100% after 2000 cycles). This novel synthetic route towards Fe3O4 is a convenient and potential way of producing a secondary energy material which is expected to be applicable in the synthesis of other metal oxide nanoparticles. PMID:23512007

Wang, Lu; Ji, Hongmei; Wang, Shasha; Kong, Lijuan; Jiang, Xuefan; Yang, Gang

2013-05-01

305

Preparation of Fe3O4Spherical Nanoporous Particles Facilitated by Polyethylene Glycol 4000  

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Full Text Available Abstract Much interest has been attracted to the magnetic materials with porous structure because of their unique properties and potential applications. In this report, Fe3O4nanoporous particles assembled from small Fe3O4nanoparticles have been prepared by thermal decomposition of iron acetylacetonate in the presence of polyethylene glycol 4000. The size of the spherical nanoporous particles is 100–200 nm. Surface area measurement shows that these Fe3O4nanoporous particles have a high surface area of 87.5 m2/g. Magnetization measurement and Mössbauer spectrum indicate that these particles are nearly superparamagnetic at room temperature. It is found that the morphology of the products is greatly influenced by polyethylene glycol concentration and the polymerization degree of polyethylene glycol. Polyethylene glycol molecules are believed to facilitate the formation of the spherical assembly.

Wang Li-Li

2009-01-01

306

Polymethylmethacrylate/Fe3O4 composite nanofiber membranes with ultra-low dielectric permittivity  

Science.gov (United States)

Ultra-low dielectric permittivity poly (methyl methacrylate)/Fe3O4 composite fiber membranes have been successfully prepared using electrospinning. The composite membranes were characterized by SEM (scanning electron microscopy), TEM (transmission electron microscopy), FT-IR (Fourier transform infrared), XRD (X-ray diffraction) and a radio frequency (RF) impedance/capacitance material analyzer. The magnetic measurement showed that the composite membranes displayed the super-paramagnetic property. The results showed that the dielectric permittivity of the composite fiber membranes was decreasing with increasing Fe3O4 nanoparticle content.

Zhang, C. C.; Li, X.; Yang, Y.; Wang, C.

2009-11-01

307

Preparation and study of magnetic and luminescence properties of Eu doped YPO4 and Fe3O4 hybrid nanocomposite  

International Nuclear Information System (INIS)

Nanoparticles based hyperthermia therapy is one possible way for a low cost effective technique in killing cancer tissues in human body. Fe3O4 and Fe3O4 at the rate YPO4:5Eu hybrid magnetic nanoparticles have been prepared by co-precipitation method and their average particle sizes are found to be 10 and 25 nm, respectively. The particles are perfectly spherical, non agglomerated and highly dispersible in water. The crystallinity of as-prepared YPO4:5Eu sample is more than Fe3O4 at the rate YPO4:5Eu hybrid magnetic nanoparticles. The chemical interaction between Fe3O4 and YPO4:5Eu has been confirmed through Fe---O-P bonding using infrared spectroscopy. The magnetization of hybrid nanocomposites shows saturation magnetization Ms = 11.1 emu/g with zero coercivity at room temperature indicating superparamagnetic behaviour

2012-12-01

308

Preparation of Fe3O4/PAM core-shell magnetic particles in reverse microemulision by E-beam irradiation  

International Nuclear Information System (INIS)

Magnetic nanoparticles were prepared by chemical co-precipitation of ferrouschloride and ferric- chloride. Fe3O4/PAM core-shell composite magnetic particles were synthesized by E-beam irradiation in reverse microemulision. The products were characterized by XRD, AFM, FTIR and PCS. The results indicate that the products were single-phase Fe3O4 of about 10 nm in diameter, and the Fe3O4/PAM particles were spherical of about 80-150 nm in diameter. It was found that size of the core-shell particles could be controlled by adjusting concentrations Of emulsification op-10, monomer AM and magnetic nanoparticles Fe3O4, and the irradiation doses. (authors)

2007-04-01

309

Enrichment of Polychlorinated Biphenyls from Aqueous Solutions Using Fe3O4 Grafted Multiwalled Carbon Nanotubes with Poly Dimethyl Diallyl Ammonium Chloride  

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In this paper, Fe3O4 nanoparticles (Fe3O4 NPs) grafted carboxyl groups of multiwalled carbon nanotubes with cationic polyelectrolyte poly (dimethyldiallylammonium chloride) (PDDA) (MWCNTs-COO?/PDDA@Fe3O4), are successfully synthesized and used for the extraction of six kinds of major toxic polychorinated biphenyls (PCBs) from a large volume of water solution. The hydrophilicity of the PDDA cage can enhance the dispersibility of sorbents in water samples, and the superparamagnetism of the Fe...

Zeng, Shaolin; Cao, Yuting; Sang, Weiguo; Li, Tianhua; Gan, Ning; Zheng, Lei

2012-01-01

310

In vitro and ex vivo evaluation of silica-coated super paramagnetic iron oxide nanoparticles (SPION) as biomedical photoacoustic contrast agent  

Science.gov (United States)

The employment of contrast agents in photoacoustic imaging has gained significant attention within the past few years for their biomedical applications. In this study, the use of silica-coated superparamagnetic iron oxide (Fe3O4) nanoparticles (SPION) was investigated as a contrast agent in biomedical photoacoustic imaging. SPIONs have been widely used as Food-and-Drug-Administration (FDA)-approved contrast agents for magnetic resonance imaging (MRI) and are known to have an excellent safety profile. Using our frequency-domain photoacoustic correlation technique ("the photoacoustic radar") with modulated laser excitation, we examined the effects of nanoparticle size, concentration and biological medium (e.g. serum, sheep blood) on its photoacoustic response in turbid media (intralipid solution). Maximum detection depth and minimum measurable SPION concentration were determined experimentally. The detection was performed using a single element transducer. The nanoparticle-induced optical contrast ex vivo in dense muscular tissues (avian pectus) was evaluated using a phased array photoacoustic probe and the strong potential of silicacoated SPION as a possible photoacoustic contrast agent was demonstrated. This study opens the way for future clinical applications of nanoparticle-enhanced photoacoustic imaging in cancer therapy.

Alwi, Rudolf; Telenkov, Sergey A.; Mandelis, Andreas; Leshuk, Timothy; Gu, Frank; Oladepo, Sulayman; Michaelian, Kirk; Dickie, Kristopher

2013-03-01

311

Localization and scintigraphy vizualization of nanocomposite based on 99mTc-phosphate with Fe3O4 and KCl nanoparticles under radiofrequency hyperthermia on animal tumor Walker-256  

International Nuclear Information System (INIS)

A comparative experimental study of the localization under the influence of constant magnetic fields and local radio frequency moderate hyperthermia for the scintigraphic imaging of malignant Walker-256 carcinosarcoma tumors by conventional 99mTc-phosphate and nanocomposite based on 99mTc-phosphate with Fe3O4 and KCl is performed. It is shown that, after the introduction of conventional 99mTc-phosphate to animals from control group, no tumor is visualized. After the introduction of nanocomposite, we observed the accumulation and the visualization of radiopharmaceuticals in the tumor with diffusion-uneven distribution. Accumulation of nanocomposite in the projection of a tumor as compared with control animals increased by more than 2 times.

2011-01-01

312

Spherical polystyrene-supported nano-Fe3O4 of high capacity and low-field separation for arsenate removal from water  

International Nuclear Information System (INIS)

Highlights: ? Nano-Fe3O4 was coated onto polystyrene (PS) beads to obtain PS-Fe3O4 for arsenate removal from water. ? PS-Fe3O4 exhibited higher capacity and faster kinetics for arsenate adsorption than Fe3O4. ? PS-Fe3O4 can be effectively separated from water under a low magnetic field (3O4 can be employed for multiple uses after regeneration with alkaline solution. - Abstract: Fe3O4 is a promising material for arsenic sequestration due to its specific affinity toward arsenic and feasible magnetic separation. How to further increase its adsorption capacity while maintain its low-field separation is an interesting but challenging task. In this study nano-Fe3O4 was successfully coated onto the outer surface of polystyrene (PS) beads of 350–400 nm in diameter by the hetero-coacervation method, and the resulting composite PS-Fe3O4 was characterized using transmission electron microscope (TEM), X-ray powder diffraction (XRD), and electrophoresis measurement (EM). Its adsorption toward arsenate was investigated as a function of solution pH, arsenic concentration, contact time, and coexisting anions. The maximum adsorption capacity of PS-Fe3O4 was 139.3 mg/g Fe3O4, 77.7% greater than that of bulky Fe3O4. More attractively, it can be readily separated from water under a low magnetic field (3O4 can be effectively regenerated by NaOH solution, and the regenerated composite beads could be employed for repeated use without significant capacity loss, indicating that nano-Fe3O4 was steadily coated onto the surface of PS beads. Generally, PS beads could be employed as a promising host to fabricate efficient composites originated from Fe3O4 or other nanoparticles for environmental remediation.

2012-12-01

313

Preparation and Characterization of Silica-Coated Magnetic–Fluorescent Bifunctional Microspheres  

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Full Text Available Abstract Bifunctional magnetic–fluorescent composite nanoparticles (MPQDs with Fe3O4MPs and Mn:ZnS/ZnS core–shell quantum dots (QDs encapsulated in silica spheres were synthesized through reverse microemulsion method and characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, vibration sample magnetometer, and photoluminescence (PL spectra. Our strategy could offer the following features: (1 the formation of Mn:ZnS/ZnS core/shell QDs resulted in enhancement of the PL intensity with respect to that of bare Mn:ZnS nanocrystals due to the effective elimination of the surface defects; (2 the magnetic nanoparticles were coated with silica, in order to reduce any detrimental effects on the QD PL by the magnetic cores; and (3 both Fe3O4MPs and Mn:ZnS/ZnS core–shell QDs were encapsulated in silica spheres, and the obtained MPQDs became water soluble. The experimental conditions for the silica coating on the surface of Fe3O4nanoparticles, such as the ratio of water to surfactant (R, the amount of ammonia, and the amount of tetraethoxysilane, on the photoluminescence properties of MPQDs were studied. It was found that the silica coating on the surface of Fe3O4could effectively suppress the interaction between the Fe3O4and the QDs under the most optimal parameters, and the emission intensity of MPQDs showed a maximum. The bifunctional MPQDs prepared under the most optimal parameters have a typical diameter of 35 nm and a saturation magnetization of 4.35 emu/g at room temperature and exhibit strong photoluminescence intensity.

Xiao Qi

2009-01-01

314

Nanoarchitectured Fe3O4 array electrode and its excellent lithium storage performance  

International Nuclear Information System (INIS)

Fe3O4 nanoparticles were deposited electrochemically on an array of Cu nanoribbons and used as the anode for lithium ion batteries. The three-dimensional (3D) nanostructure of the Fe3O4 anode was characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Galvanostatic cycling tests revealed that the 3D nanostructured Fe3O4 anode exhibited a superior performance. Reversible capacity was measured as high as 870 mAh g?1 after 280 cycles (at a current density of 385 mA g?1, 0.42 C) and also shown an excellent rate capability that was determined at 231 mAh g?1 under the rate of 8000 mA g?1 (?9 C). The superior performance of the 3D nanostructured Fe3O4 electrode has been attributed to its peculiar structure, which allows one-dimensional electron transport on the array, as well as to the decrease in interparticle contact resistance.

2012-09-01

315

Synthesis of Fe3O4-LaF3:Ce,Tb nanocomposites with bright fluorescence and strong magnetism  

International Nuclear Information System (INIS)

In this paper, fluorescent-magnetic Fe3O4-LaF3:Ce,Tb nanocomposites were synthesized by combining fluorescent LaF3:Ce,Tb and magnetic Fe3O4 nanoparticles into new 'two-in-one' entities. The obtained Fe3O4-LaF3:Ce,Tb nanocomposites were small (about 30 nm in diameter) and well dispersed in water. Under ultraviolet light irradiation, the Fe3O4-LaF3:Ce,Tb nanocomposites emitted bright green fluorescence, and they could be easily manipulated by an external magnetic field. Such bifunctional nanocomposites may find many biomedical applications, such as cancer detection and drug delivery. And the method we used can be extended to the synthesis of other nanocomposites based on lanthanide-doped materials and metal oxides.

2009-02-01

316

Spectroscopic and photoluminescence studies on optically transparent magnetic nanocomposites based on sol-gel glass: Fe3O4  

International Nuclear Information System (INIS)

Sol-gel glasses with Fe3O4 nanoparticles having particle sizes laying in the range 10-20 nm were encapsulated in the porous network of silica resulting in nanocomposites having both optical and magnetic properties. Spectroscopic and photoluminescence studies indicated that Fe3O4 nanocrystals are embedded in the silica matrix with no strong Si-O-Fe bonding. The composites exhibited a blue luminescence. The optical absorption edge of the composites red shifted with increasing concentration of Fe3O4 in the silica matrix. There is no obvious shift in the position of the luminescence peak with the concentration of Fe3O4 except that the intensity of the peak is decreased. The unique combinations of magnetic and optical properties are appealing for magneto-optical applications

2008-01-01

317

Effect of silica shell thickness of Fe3O4–SiOx core–shell nanostructures on MRI contrast  

International Nuclear Information System (INIS)

Core–shell magnetic nanostructures (MNS) such as Fe3O4–SiOx, are being explored for their potential applications in biomedicine, such as a T2 (dark) contrast enhancement agent in magnetic resonance imaging (MRI). Herein, we present the effect of silica shell thickness on its r2 relaxivity in MRI as it relates to other physical parameters. In this effort initially, monodispersed Fe3O4 MNS (nominally 9 nm size) were synthesized in organic phase via a simple chemical decomposition method. To study effect of shell thickness of silica of Fe3O4–SiOx core shell on r2 relaxivity, the reverse micro-emulsion process was used to form silica coating of 5, 10 and 13 nm of silica shell around the MNS, while polyhedral oligomeric silsesquioxane was used to form very thin layer on the surface of MNS; synthesized nanostructures were characterized by transmission electron microscopy (TEM) and high resolution TEM (HRTEM), superconducting quantum interference device magnetometry and MRI. Our observation suggests that, with increase in thickness of silica shell in Fe3O4–SiOx core–shell nanostructure, r2 relaxivity decreases. The decrease in relaxivity could be attributed to increased distance between water molecules and magnetic core followed by change in the difference in Larmor frequencies (??) of water molecules. These results provide a rational basis for optimization of SiOx-coated MNS for biomedical applications.

2013-03-01

318

Fabrication, characterization and measurement of thermal conductivity of Fe 3O 4 nanofluids  

Science.gov (United States)

Magnetite Fe 3O 4 nanoparticles were synthesized by a co-precipitation method at different pH values. The products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electronic microscopy. Their magnetic properties were evaluated on a vibrating sample magnetometer. The results show that the shape of the particles is cubic and they are superparamagnetic at room temperature. Magnetic nanofluids were prepared by dispersing the Fe 3O 4 nanoparticles in water as a base fluid in the presence of tetramethyl ammonium hydroxide as a dispersant. The thermal conductivity of the nanofluids was measured as a function of volume fraction and temperature. The results show that the thermal conductivity ratio of the nanofluids increases with increase in temperature and volume fraction. The highest enhancement of thermal conductivity was 11.5% in the nanofluid of 3 vol% of nanoparticles at 40 °C. The experimental results were also compared with the theoretical models.

Abareshi, Maryam; Goharshadi, Elaheh K.; Mojtaba Zebarjad, Seyed; Khandan Fadafan, Hassan; Youssefi, Abbas

2010-12-01

319

Fabrication, characterization and measurement of thermal conductivity of Fe3O4 nanofluids  

International Nuclear Information System (INIS)

Magnetite Fe3O4 nanoparticles were synthesized by a co-precipitation method at different pH values. The products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electronic microscopy. Their magnetic properties were evaluated on a vibrating sample magnetometer. The results show that the shape of the particles is cubic and they are superparamagnetic at room temperature. Magnetic nanofluids were prepared by dispersing the Fe3O4 nanoparticles in water as a base fluid in the presence of tetramethyl ammonium hydroxide as a dispersant. The thermal conductivity of the nanofluids was measured as a function of volume fraction and temperature. The results show that the thermal conductivity ratio of the nanofluids increases with increase in temperature and volume fraction. The highest enhancement of thermal conductivity was 11.5% in the nanofluid of 3 vol% of nanoparticles at 40 oC. The experimental results were also compared with the theoretical models.

2010-12-01

320

Antifungal activity of multifunctional Fe3O4-Ag nanocolloids  

International Nuclear Information System (INIS)

In recent years, rapid increase has been observed in the population of microbes that are resistant to conventionally used antibiotics. Antifungal drug therapy is no exception and now resistance to many of the antifungal agents in use has emerged. Therefore, there is an inevitable and urgent medical need for antibiotics with novel antimicrobial mechanisms. Aspergillus glaucus is the potential cause of fatal brain infections and hypersensitivity pneumonitis in immunocompromised patients and leads to death despite aggressive multidrug antifungal therapy. In the present article, we describe the antifungal activity of multifunctional core-shell Fe3O4-Ag nanocolloids against A. glaucus isolates. Controlled experiments are also carried out with Ag nanocolloids in order to understand the role of core (Fe3O4) in the antifungal action. The minimum inhibitory concentration (MIC) of nanocolloids is determined by the micro-dilution method. MIC of A. glaucus is 2000 ?g/mL. The result is quite promising and requires further investigations in order to develop a treatment methodology against this death causing fungus in immunocompromised patients. - Research Highlights: ?Synthesis of Fe3O4-Ag core-shell nanocolloids. ?Antifungal activity of Fe3O4-Ag nanocolloids against Aspergillus glaucus isolates. ?The MIC value for A. glaucus is 2000 ?g/mL. ?Antifungal activity is better or comparable with most prominent antibiotics.

2011-05-01

 
 
 
 
321

Facile synthesis of hierarchical core-shell Fe3O4@MgAl-LDH@Au as magnetically recyclable catalysts for catalytic oxidation of alcohols.  

Science.gov (United States)

A novel core-shell structural Fe(3)O(4)@MgAl-LDH@Au nanocatalyst was simply synthesized via supporting Au nanoparticles on the MgAl-LDH surface of Fe(3)O(4)@MgAl-LDH nanospheres. The catalyst exhibited excellent activity for the oxidation of 1-phenylethanol, and can be effectively recovered by using an external magnetic field. PMID:22068662

Mi, Fei; Chen, Xitao; Ma, Yuewen; Yin, Shuangtao; Yuan, Fanglong; Zhang, Hui

2011-12-28

322

Facile synthesis of pectin coated Fe3O4 nanospheres by the sonochemical method  

Science.gov (United States)

Pectin coated Fe3O4 magnetic nanospheres (PCMNs) were synthesized by the sonochemical method. The Fe3O4 nanoparticles were prepared by chemical precipitation as reported in the previous articles, and the PCMNs were characterized by transmission electron microscopy, dynamic light scattering, thermogravimetric analysis, Fourier-transform infrared spectroscopy, a vibrating sample magnetometer and energy dispersive X-ray spectrum. The results indicated that the magnetic nanoparticles have been coated by pectin, magnetite content of which was up to 63%, with the saturation magnetization being 32.69 emu/g. The formation mechanism and further application of PCMNs have also been discussed. The results show that the PCMNs can be applied to biomedical applications.

Dai, Junjun; Wu, Shixi; Jiang, Wei; Li, Pingyun; Chen, Xiaolong; Liu, Li; Liu, Jie; Sun, Danping; Chen, Wei; Chen, Binhua; Li, Fengsheng

2013-04-01

323

Synthesis of talc/Fe3O4 magnetic nanocomposites using chemical co-precipitation method  

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Katayoon Kalantari,1 Mansor Bin Ahmad,1,* Kamyar Shameli,1,2,* Roshanak Khandanlou11Department of Chemistry, Universiti Putra Malaysia, Serdang, Malaysia; 2Nanotechnology and Advance Materials Department, Materials and Energy Research Center, Karaj, Alborz, Karaj, Iran*These authors contributed equally to this workAbstract: The aim of this research was to synthesize and develop a new method for the preparation of iron oxide (Fe3O4) nanoparticles on talc layers using an environmentally friendl...

Kalantari K; Bin Ahmad M; Shameli K; Khandanlou R

2013-01-01

324

Sensing behavior study of silica-coated Ag nanoparticles deposited on glassy carbon toward nitrobenzene  

International Nuclear Information System (INIS)

In this study, we report the synthesis and characterization of silica-coated silver core/shell nanostructures (NSs) and their sensing behavior when deposited on glassy carbon (GC) electrode for nitrobenzene (NB) detection. Synthesized silica-coated silver core/shell NSs were characterized for their chemical, structural and morphological properties. TEM analysis confirmed that the silica-coated silver nanoparticles (size ?200 nm) are spherical in shape and the core diameter is ?38 nm. FT-IR spectra also confirmed the coating of silica on the surface of silver nanoparticles. Cyclic voltammetry studies of NB with silica-coated silver core–shell nanoparticles-modified GC electrodes revealed two cathodic peaks at ?0.74 V (C1) and ?0.34 V (C2) along with two anodic peaks at ?0.64 V (A1) and ?0.2 V (A2). Enhanced cathodic peak current (C1, IP) of the core–shell NSs-modified electrode is observed relative to bare and silica-modified electrodes. Amperometric studies revealed a very high current sensitivity (114 nA/nM) and linearly dependent reduction current with NB amount in the low concentration range and a detection limit of 25 nM. Moreover, the core–shell NSs-modified electrode showed good reproducibility and selectivity toward NB in the presence of many cationic, anionic, and organic interferents.

2012-10-01

325

Sensing behavior study of silica-coated Ag nanoparticles deposited on glassy carbon toward nitrobenzene  

Energy Technology Data Exchange (ETDEWEB)

In this study, we report the synthesis and characterization of silica-coated silver core/shell nanostructures (NSs) and their sensing behavior when deposited on glassy carbon (GC) electrode for nitrobenzene (NB) detection. Synthesized silica-coated silver core/shell NSs were characterized for their chemical, structural and morphological properties. TEM analysis confirmed that the silica-coated silver nanoparticles (size {approx}200 nm) are spherical in shape and the core diameter is {approx}38 nm. FT-IR spectra also confirmed the coating of silica on the surface of silver nanoparticles. Cyclic voltammetry studies of NB with silica-coated silver core-shell nanoparticles-modified GC electrodes revea