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1

Ag-deposited silica-coated Fe3O4 magnetic nanoparticles catalyzed reduction of p-nitrophenol  

International Nuclear Information System (INIS)

In this paper, a novel approach was successfully developed for advanced catalyst Ag-deposited silica-coated Fe3O4 magnetic nanoparticles, which possess a silica coated magnetic core and growth active silver nanoparticles on the outer shell using n-butylamine as the reductant of AgNO3 in ethanol. The as-synthesized nanoparticles have been characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectra (FT-IR), vibration sample magnetometer (VSM), and have been exploited as a solid phase catalyst for the reduction of p-nitrophenol in the presence of NaBH4 by UV-vis spectrophotometry. The obtained products exhibited monodisperse and bifunctional with high magnetization and excellent catalytic activity towards p-nitrophenol reduction. As a result, the as-obtained nanoparticles showed high performance in catalytic reduction of p-nitrophenol to p-aminophenol with conversion of 95% within 14 min in the presence of an excess amount of NaBH4, convenient magnetic separability, as well as remained activity after recycled more than 6 times. The Fe3O4-SiO2-Ag functional nanostructure could hold great promise for various catalytic reactions.

2

Transfer of silica-coated magnetic (Fe3O4) nanoparticles through food: a molecular and morphological study in zebrafish.  

Science.gov (United States)

The increasing use of magnetic iron oxide nanoparticles (NPs) in biomedical applications has prompted extensive investigation of their interactions with biological systems also through animal models. A variety of toxic effects have been detected in NP-exposed fish and fish embryos, including oxidative stress and associated changes, such as lipid oxidation, apoptosis, and gene expression alterations. The main exposure route for fish is through food and the food web. This study was devised to investigate the effects of silica-coated NP administration through food in zebrafish (ZF, Danio rerio). Silica-coated magnetic NPs were administered to ZF through feed (zooplankton) from day 1 to 15 posthatching (ph). Larvae were examined 6 and 15 days ph and adults 3 and 6 months ph. A multidisciplinary approach, including morphometric examination; light, transmission electron, and confocal microscopy; inductively coupled plasma emission spectrometry; and real-time polymerase chain reaction, was applied to detect NP accumulation, structural and ultrastructural damage, and activation of detoxification processes in larvae and adults. Our findings document that the silica-coated NPs: (1) do not induce toxicity in ZF, (2) are excreted through feces, and (3) do not activate detoxification processes or promote tissue/cell injury. PMID:25372245

Piccinetti, Chiara Carla; Montis, Costanza; Bonini, Massimo; Laurà, Rosaria; Guerrera, Maria Cristina; Radaelli, Giuseppe; Vianello, Fabio; Santinelli, Veronica; Maradonna, Francesca; Nozzi, Valentina; Miccoli, Andrea; Olivotto, Ike

2014-12-01

3

Dielectric behavior of Bi–Fe3O4 nanocomposite and Fe3O4 nanoparticles prepared via mechanochemical processing  

International Nuclear Information System (INIS)

Bi–Fe3O4 nanocomposite and Fe3O4 nanoparticles were prepared via mechanochemical processing. Structural, compositional, and morphological characterizations of products were carried out by using X-ray diffraction, Scanning electron microscopy and Transmission electron microscopy. The investigation of dielectric constant (??), dielectric loss tangent (tan ?), and AC resistivity was carried out in an applied field with frequency range of 100–1 MHz and at temperatures from 79 to 300 K. The variation of DC electrical resistivity with temperature was investigated with a two probe method from 79 to 300 K. It was found that ??and tan ? decrease with increasing frequency and temperature. The DC resistivity decreases with increasing temperature. The experimental results show that both AC and DC resistivity, dielectric constants and activation energy of Bi–Fe3O4 nanocomposite are larger than those related to Fe3O4 and tan ? of the composite is much lower than that of Fe3O4. - Highlights: • Bi–Fe3O4 nanocomposite and Fe3O4 nanoparticles were prepared via ball milling. • Their dielectric loss tangent (tan ?) and AC resistivity (?AC) were determined. • We examine the DC resistivity of samples within the temperature range from 79 to 300 K • The AC and DC dielectric constants of Bi–Fe3O4 are larger than those of Fe3O4. • The activation energy of Bi–Fe3O4 is larger than of Fe3O4

4

Synthesis and properties of Au-Fe3O4 and Ag-Fe3O4 heterodimeric nanoparticles  

Science.gov (United States)

Monodisperse Au-Fe3O4 heterodimeric nanoparticles (NPs) were prepared by injecting precursors into a hot reaction solution. The size of Au and Fe3O4 particles can be controlled by changing the injection temperature. UV-Vis spectra show that the surface plasma resonance band of Au-Fe3O4 heterodimeric NPs was evidently red-shifted compared with the resonance band of Au NPs of similar size. The as-prepared heterodimeric Au-Fe3O4 NPs exhibited superparamagnetic properties at room temperature. The Ag-Fe3O4 heterodimeric NPs were also prepared by this synthetic method simply using AgNO3 as precursor instead of HAuCl4. It is indicated that the reported method can be readily extended to the synthesis of other noble metal conjugated heterodimeric NPs.

Ding, Hao; Shen, Cheng-Min; Hui, Chao; Xu, Zhi-Chuan; Li, Chen; Tian, Yuan; Shi, Xue-Zhao; Gao, Hong-Jun

2010-06-01

5

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.

6

Enzymes immobilization on Fe3O4-gold nanoparticles  

International Nuclear Information System (INIS)

In the present study Fe3O4 magnetic nanoparticles were synthesized by coprecipitation of Fe2+ and Fe3+ from chlorides. In the next step magnetite-gold core-shell nanoparticles were synthesized from HAuCl4 using an ethanol as a reducing agent. Finally, magnetic nanoparticles were functionalized by hexadecanethiol. The immobilization of biological molecules (trypsin and glucose oxidase) to the thiol-modified and unmodified magnetite-gold nanoparticles surface was tested. The resulting nanoparticles were characterized by infrared spectroscopy, differential scanning calorimetry, Mössbauer spectroscopy and transmission electron microscopy.

7

Magnetic Pickering emulsions stabilized by Fe3O4 nanoparticles.  

Science.gov (United States)

Superparamagnetic Fe(3)O(4) nanoparticles prepared by a classical coprecipitation method were used as the stabilizer to prepare magnetic Pickering emulsions, and the effects of particle concentration, oil/water volume ratio, and oil polarity on the type, stability, composition, and morphology of these functional emulsions were investigated. The three-phase contact angle (?(ow)) of the Fe(3)O(4) nanoparticles at the oil-water interface was evaluated using the Washburn method, and the results showed that for nonpolar and weakly polar oils of dodecane and silicone, ?(ow) is close to 90°, whereas for strongly polar oils of butyl butyrate and 1-decanol, ?(ow) is far below 90°. Inherently hydrophilic Fe(3)O(4) nanoparticles can be used to prepare stable dodecane-water and silicone-water emulsions, but they cannot stabilize butyl butyrate-water and decanol-water mixtures with macroscopic phase separation occurring, which is in good agreement with the contact angle data. Emulsions are of the oil-in-water type for both dodecane and silicone oil, and the average droplet size increases with an increase in the oil volume fraction. For stable emulsions, not all of the particles are adsorbed to drop interfaces; the fraction adsorbed decreases with an increase in the initial oil volume fraction. Changes in the particle concentration have no obvious influence on the stability of these emulsions, even though the droplet size decreases with concentration. PMID:21344923

Zhou, Jun; Qiao, Xiuying; Binks, Bernard P; Sun, Kang; Bai, Mingwen; Li, Yunlong; Liu, Yi

2011-04-01

8

Electrochemical sensing behaviour of Ni doped Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Ni doped Fe3O4 nanoparticles were synthesized by simple hydrothermal method. The prepared nanomaterials were characterized by X-ray diffraction analysis, DRS-UV-Visible spectroscopy and field emission scanning electron microscopy. The XRD confirms the phase purity of the synthesized Ni doped Fe3O4 nanoparticles. The optical property of Ni doped Fe3O4 nanoparticles were studied by DRS UV-Visible analysis. The electrochemical sensing property of pure and Ni doped Fe3O4 nanoparticles were examined using uric acid as an analyte. The obtained results indicated that the Ni doped Fe3O4 nanoparticles exhibited higher electrocatalytic activity towards uric acid

9

Functionalized magnetic core–shell Fe3O4-SiO2 nanoparticles for sensitive detection and removal of Hg2+  

International Nuclear Information System (INIS)

The Fe3O4 nanoparticles [NPs] coated with silica nanoparticles were designed and prepared, the obtained Fe3O4-SiO2 NPs have uniform spherical morphology with a mean diameter of about 22 nm. The inert silica coating on the surface of Fe3O4 NPs not only significantly prevented their aggregation in solution but also improved their chemical stability and provided wider sites for surface modification with organic chemosensors. Subsequently an attempt had been made that the as-synthesized Fe3O4-SiO2 NPs were modified by N-(rhodamine-6G) lactam–ethylenediamine, the functionalized magnetic Fe3O4-SiO2 NPs (Fe3O4-SiO2-Rho) served as a “naked eye” fluorescent sensor to detect Hg2+. The Fe3O4-SiO2-Rho NPs exhibited selective “turn-on” type fluorescent change from colorless to orange when adding to Hg2+. In addition, the adsorption experiments revealed that the Fe3O4-SiO2-Rho NPs had effective removal toward Hg2+. Moreover, the functionalized Fe3O4-SiO2 microspheres displayed superparamagnetic properties, which made it easier to separate the nanocomposites from the liquid phase by adding an external magnetic field. Our efforts provided a potential magnetic nanomaterial potential magnetic nanomaterial for sensitive detection and removal toward Hg2+ simultaneously.Graphical AbstractA rhodamine 6G derivative functionalized Fe3O4-SiO2 nanoparticles were designed and synthesized (as Fe3O4-SiO2-Rho). The Fe3O4-SiO2-Rho exhibited selective “turn-on” type fluorescent change from colorless to orange with Hg2+, which constituted an Hg2+-selective fluorescent colorimetric nanosensor.

10

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)

11

Enhanced specific absorption rate in silanol functionalized Fe3O4 core-shell nanoparticles: study of Fe leaching in Fe3O4 and hyperthermia in L929 and HeLa cells.  

Science.gov (United States)

Core-shell Fe3O4-SiO2 magnetic nanoparticles (MNPs) have been synthesized using a simple synthesis procedure at different temperatures. These MNPs are used to investigate the effect of surface coating on specific absorption rate (SAR) under alternating magnetic field. The temperature achieved by silica coated Fe3O4 is higher than that by uncoated MNPs (Fe3O4). This can be attributed to extent of increase in Brownian motion for silica coated MNPs. The sample prepared at optimized temperature of 80°C shows the highest SAR value of 111W/g. It is found that SAR value decreases with increase in shell thickness. The chemical stability of these samples is analyzed by leaching experiments at pH 2-7. The silica coated samples are stable up to 7 days even at pH 2. Biocompatibility of the MNPs is evaluated in vitro by assessing their cytotoxicity on L929 and human cervical cancer cells (HeLa cells) using sulforhodamine-B assay. Their hyperthermic killing ability is also evaluated in HeLa cells using the same method. Cells treated with MNPs along with induction heating show decrease in viability as compared to that without induction heating. Further, cell death is found to be ?55% more in cells treated with silica coated MNPs under induction heating as compared to untreated control. These results establish the efficacy of Fe3O4-SiO2 prepared at 80°C in killing of tumor cells by cellular hyperthermia. PMID:25089699

Majeed, Jerina; Pradhan, Lina; Ningthoujam, Raghumani Singh; Vatsa, Rajesh Kumar; Bahadur, Dhirendra; Tyagi, Avesh Kumar

2014-10-01

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Spectroscopic characterization of magnetic Fe3O4@Au core shell nanoparticles.  

Science.gov (United States)

The magnetic nanoparticles iron oxide (Fe3O4) nanoparticles and iron oxide/gold core-shell (Fe3O4/Au) nanoparticles were synthesized and their catalytic photo-degradation activity towards malathion as example of organophosphorus pesticides were reported. Iron oxide (Fe3O4) magnetic nanoparticle was successfully prepared through co-precipitation method by the reduction of ferric chloride (FeCl3) using ascorbic acid. The morphology of the prepared nanoparticles was characterized by the TEM and XRD (X-ray diffraction) techniques. Degradation of 10ppm of malathion in the presence of these nanoparticles under UV radiation was monitored using (HPLC) and UV-visible spectra. Fe3O4/Au nanoparticles showed higher efficiency in photo-degradation of malathion than Fe3O4 ones. PMID:25617979

Fouad, Dina M; El-Said, Waleed A; Mohamed, Mona B

2015-04-01

13

Fe3O4 nanoparticles grown on graphene as advanced electrode materials for supercapacitors  

Science.gov (United States)

A novel composite of magnetite (Fe3O4) nanoparticles (NPs) grown on reduced graphene oxide (rGO) has been synthesized by a facile hydrothermal technique without any surfactants or templates. In this method, the growth of Fe3O4 NPs and the reduction of graphene oxide (GO) are completed in one single step. Moreover, we have prepared Fe3O4 microcubes and Fe3O4/carbon nanotubes (CNTs) composite under the same condition. The electrochemical properties of the as-prepared samples are investigated as advanced electrode materials for supercapacitors. It is found that the Fe3O4/rGO nanocomposite displays much higher specific capacitances and better cycle stability than those of pure Fe3O4 and Fe3O4/CNTs composite. Specifically, it exhibits a high specific discharge capacitance of 220.1 F g-1 at 0.5 A g-1 and remains stable after 3000 charge/discharge cycles. The improvement of the electrochemical performances of Fe3O4/rGO may be attributed to the chemical interaction between rGO and Fe3O4, lower agglomeration and smaller particle size of Fe3O4.

Wang, Qinghong; Jiao, Lifang; Du, Hongmei; Wang, Yijing; Yuan, Huatang

2014-01-01

14

Photoluminescence and photothermal effect of Fe3O4 nanoparticles for medical imaging and therapy  

International Nuclear Information System (INIS)

Photoluminescence (PL) of Fe3O4 nanoparticle was observed from the visible to near-infrared (NIR) range by laser irradiation at 407?nm. PL spectra of ?10?nm diameter Fe3O4 nanoparticles organized in different spatial configuration, showed characteristic emissions with a major peak near 560?nm, and two weak peaks near 690?nm and 840?nm. Different band gap energies were determined for these Fe3O4 nanoparticle samples corresponding to, respectively, the electron band structures of the octahedral site (2.2?eV) and the tetrahedral site (0.9?eV). Photothermal effect of Fe3O4 nanoparticles was found to be associated with the photoluminescence emissions in the NIR range. Also discussed is the mechanism responsible for the photothermal effect of Fe3O4 nanoparticles in medical therapy.

15

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.

16

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

17

Size dependent structural and magnetic properties of FeO-Fe3O4 nanoparticles  

Science.gov (United States)

The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase.The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase. Electronic supplementary information (ESI) available: The particle synthesis procedure and characterization techniques are described. Fig. S1, S2 and S3 representing field and zero field cooled magnetization hysteresis loops recorded at different temperatures are shown. See DOI: 10.1039/c3nr04562e

Lak, Aidin; Kraken, Mathias; Ludwig, Frank; Kornowski, Andreas; Eberbeck, Dietmar; Sievers, Sibylle; Litterst, F. J.; Weller, Horst; Schilling, Meinhard

2013-11-01

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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

19

Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composite for laccase immobilization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

20

Oriented assembly of Fe3O4 nanoparticles into monodisperse hollow single-crystal microspheres.  

Science.gov (United States)

Magnetite nanoparticles of Fe3O4 were found to assemble into monodisperse hollow Fe3O4 microspheres with tunable diameters ranging from 200 to 400 nm and open pores on the shells in ethylene glycol in the presence of dodecylamine (DDA). The oriented assembly of nanoparticles conferred the individual hollow Fe3O4 microspheres a remarkable feature of single crystals. The morphologies of the products could be easily manipulated by varying the synthesis parameters. Increasing the concentration of DDA led to an obvious shape evolution of the products from rhombic nanoparticles to hollow microspheres, solid microspheres, and finally irregular nanoparticles, which were mainly attributed to the special self-assembly phenomenon of Fe3O4 nanoparticles in the solvothermal process. PMID:17064123

Yu, Dabin; Sun, Xiaoquan; Zou, Jiwei; Wang, Zirong; Wang, Feng; Tang, Kun

2006-11-01

 
 
 
 
21

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.

22

Versatile functionalization of Fe 3O 4 nanoparticles via RAFT polymerization and click chemistry  

Science.gov (United States)

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 Fe 3O 4 nanoparticles surface together with click chemistry. In a single pot procedure, azide-functionalized CTA, alkyne-functionalized Fe 3O 4 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 Fe 3O 4 nanoparticles using RAFT polymerization and click chemistry.

Zhou, Yang; Wang, Shixing; Xie, Keqiang; Dai, Yongnian; Ma, Wenhui

2011-10-01

23

Zero-field-cooled and field-cooled susceptibility in superspin-glasses and superparamagnets: $Fe_3 O_4$ and gold-coated $Fe_3 O_4$ nanoparticles  

CERN Document Server

We have measured zero-field cooled (ZFC) susceptibility ($\\chi_{ZFC}$) and field-cooled (FC) susceptibility ($\\chi_{FC}$) of Fe$_{3}$O$_{4}$ nanoparticles and gold-coated Fe$_{3}$O$_{4}$ (F$_{3}$O$_{4}$@Au) nanoparticles as a function of temperature. The interparticle spacing of core Fe$_{3}$O$_{4}$ nanoparticles is increased due to the Au shell in F$_{3}$O$_{4}$@Au nanoparticles. Our results are compared with numerical calculations on the scaling form of ZFC and FC susceptibility based on the superparamagnetic blocking model. Fe$_{3}$O$_{4}$ nanoparticles exhibits a superspin-glass--like behavior. The susceptibility is characterized by the flatness or decrease of the FC susceptibility below a peak temperature ($T_{b}$) of the ZFC susceptibility. The magnetic field dependence of $T_{b}$ forms a critical line with an exponent $p = 1.78 \\pm 0.36$, close to the de Almeida-Thouless exponent (= 3/2). This line is the phase boundary between the SPM and SSG phases. Fe$_{3}$O$_{4}$@Au nanoparticles exhibit a superpar...

Fullem, S I; Suzuki, M; Wang, L; Zhong, C J; Fullem, Sharbani I.; Suzuki, Itsuko S.; Suzuki, Masatsugu; Wang, Lingyan; Zhong, Chuan-Jian

2006-01-01

24

Exceeding natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation  

Science.gov (United States)

Magnetic nanoparticles have attracted much research interest in the past decades due to their potential applications in microwave devices. Here, we adopted a novel technique to tune cut-off frequency exceeding the natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation. We observed that the cut-off frequency can be enhanced from 5.3 GHz for Fe3O4 to 6.9 GHz forFe3O4@SiO2 core-shell structure superparamagnetic nanoparticles, which are much higher than the natural resonance frequency of 1.3 GHz for Fe3O4 bulk material. This finding not only provides us a new approach to enhance the resonance frequency beyond the Snoek's limit, but also extend the application for superparamagnetic nanoparticles to microwave devices.

Song, Ning-Ning; Yang, Hai-Tao; Liu, Hao-Liang; Ren, Xiao; Ding, Hao-Feng; Zhang, Xiang-Qun; Cheng, Zhao-Hua

2013-11-01

25

Exceeding natural resonance frequency limit of monodisperse Fe(3)O(4) nanoparticles via superparamagnetic relaxation.  

Science.gov (United States)

Magnetic nanoparticles have attracted much research interest in the past decades due to their potential applications in microwave devices. Here, we adopted a novel technique to tune cut-off frequency exceeding the natural resonance frequency limit of monodisperse Fe3O4 nanoparticles via superparamagnetic relaxation. We observed that the cut-off frequency can be enhanced from 5.3?GHz for Fe3O4 to 6.9?GHz forFe3O4@SiO2 core-shell structure superparamagnetic nanoparticles, which are much higher than the natural resonance frequency of 1.3?GHz for Fe3O4 bulk material. This finding not only provides us a new approach to enhance the resonance frequency beyond the Snoek's limit, but also extend the application for superparamagnetic nanoparticles to microwave devices. PMID:24196377

Song, Ning-Ning; Yang, Hai-Tao; Liu, Hao-Liang; Ren, Xiao; Ding, Hao-Feng; Zhang, Xiang-Qun; Cheng, Zhao-Hua

2013-01-01

26

Temperature dependence of magnetic property and photocatalytic activity of Fe3O4/hydroxyapatite nanoparticles  

International Nuclear Information System (INIS)

Fe3O4/hydroxyapatite (HAP) nanoparticles have been developed as a novel photocatalyst support, based on the embedment of magnetic Fe3O4 particles into HAP shell via homogeneous precipitation method. The resultant nanoparticles were characterized by transmission electron microscope (TEM) and X-ray diffraction (XRD). These particles were almost spherical in shape, rather monodisperse and have a unique size of about 25 nm in diameter. The effect of calcination temperature on magnetic property and photocatalytic activity of Fe3O4/HAP nanoparticles was investigated in detail. The obtained results showed that the Fe3O4/HAP nanoparticles calcined at 400 oC possessed good magnetism and photocatalytic activity in comparison with that calcined at other temperatures.

27

Sonochemical synthesis, structure and magnetic properties of air-stable Fe3O4/Au nanoparticles  

International Nuclear Information System (INIS)

Air-stable nanoparticles of Fe3O4/Au were prepared via sonolysis of a solution mixture of hydrogen tetrachloroaureate(III) trihydrate (HAuCl4) and (3-aminopropyl)triethoxysilane (APTES)-coated Fe3O4 nanoparticles with further drop-addition of sodium citrate. The Fe3O4/Au nanoparticles were characterized by x-ray powder diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and superconducting quantum interference device (SQUID) magnetometry. Nanoparticles of Fe3O4/Au obtained under appropriate conditions possess a very high saturation magnetization of about 63 emu g-1 and their average diameter is about 30 nm

28

Spin transport in molecules studied by Fe3O4/molecule nanoparticles  

Science.gov (United States)

In this work, we synthesize single molecular layer coated Fe3O4 nanoparticles to form the network of the molecular junction spin valves. The Fe3O4 nanoparticles chemically bond with molecules without any physically absorbed molecules, leading to one monolayer molecule coated on nanoparticles. The magnetoresistance (MR) of cold-pressed Fe3O4/oleic acid nanoparticles is more than two times larger than bare Fe3O4 nanoparticles, indicating weaker spin scattering in molecules. Furthermore, the MR ratio is as high as ˜21 % at room temperature for Fe3O4/alkane molecule nanoparticles. Interestingly, even though the resistance spans about two decades as the alkane molecular length varies from 0.7 to 2.5 nm, the MR ratio stays approximately constant. This molecular length independent spin valve MR, originated from the weaker hyperfine interaction strength of the ?-electrons in alkane molecules, entails room-temperature spin-conserving transport in molecular materials. Using the size of ˜500 nm Fe3O4 nanoparticles, a large MR is achieved in a relatively low magnetic field. This feature opens a door for the development of future spin-based molecular electronics. Moreover, spin injection at the interface of Fe3O4/stearic acid molecule is investigated in a comparative study between Fe3O4 nanoparticles chemically bonded (ChemNPs) and physically absorbed (PhyNPs) molecules. A MR of 12 % at room temperature is observed in ChemNPs, in sharp contrast to the zero MR ratio in PhyNPs, reflecting that the chemical bonding is crucial for spin injection. These results show that the hybrid nanoparticles provide a simple approach to study the spin transport in molecules.

Yue, F. J.; Wang, S.; Wu, D.

2013-05-01

29

Superparamagnetic Au-Fe3O4 nanoparticles: one-pot synthesis, biofunctionalization and toxicity evaluation  

Science.gov (United States)

Superparamagnetic Au-Fe3O4 bifunctional nanoparticles have been synthesized using a single step hot-injection precipitation method. The synthesis involved using Fe(CO)5 as iron precursor and HAuCl4 as gold precursor in the presence of oleylamine and oleic acid. Oleylamine helps in reducing Au3+ to Au0 seeds which simultaneously oxidizes Fe(0) to form Au-Fe3O4 bifunctional nanoparticles. Triton® X-100 was employed as a highly viscous solvent to prevent agglomeration of Fe3O4 nanoparticles. Detailed characterization of these nanoparticles was performed by using x-ray powder diffraction, transmission electron microscopy, scanning tunneling electron microscopy, UV-visible spectroscopy, Mössbauer and magnetometry studies. To evaluate these nanoparticles’ applicability in biomedical applications, L-cysteine was attached to the Au-Fe3O4 nanoparticles and cytotoxicity of Au-Fe3O4 nanoparticles was tested using CHO cells by employing MTS assay. L-cysteine modified Au-Fe3O4 nanoparticles were qualitatively characterized using Fourier transform infrared spectroscopy and Raman spectroscopy; and quantitatively using acid ninhydrin assay. Investigations reveal that that this approach yields Au-Fe3O4 bifunctional nanoparticles with an average particle size of 80 nm. Mössbauer studies indicated the presence of Fe in Fe3+ in A and B sites (tetrahedral and octahedral, respectively) and Fe2+ in B sites (octahedral). Magnetic measurements also indicated that these nanoparticles were superparamagnetic in nature due to Fe3O4 region. The saturation magnetization for the bifunctional nanoparticles was observed to be ˜74 emu g-1, which is significantly higher than the previously reported Fe3O4 nanoparticles. Mössbauer studies indicated that there was no significant Fe(0) impurity that could be responsible for the superparamagnetic nature of these nanoparticles. None of the investigations showed any presence of other impurities such as Fe2O3 and FeOOH. These Au-Fe3O4 bifunctional nanoparticles showed no significant cytotoxicity to the CHO cells up to 48 h even at concentrations of 1 mg ml-1 making them suitable for biomedical applications such as local heat generators (hyperthermia) for cancer treatment and drug delivery vehicles.

Pariti, A.; Desai, P.; Maddirala, S. K. Y.; Ercal, N.; Katti, K. V.; Liang, X.; Nath, M.

2014-09-01

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Nanoparticle size matters in the formation of plasma protein coronas on Fe3O4 nanoparticles.  

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When nanoparticles (NPs) enter into biological systems, proteins would interact with NPs to form the protein corona that can critically impact the biological identity of the nanomaterial. Owing to their fundamental scientific interest and potential applications, Fe3O4 NPs of different sizes have been developed for applications in cell separation and protein separation and as contrast agents in magnetic resonance imaging (MRI), etc. Here, we investigated whether nanoparticle size affects the formation of protein coronas around Fe3O4 NPs. Both the identification and quantification results demonstrated that particle size does play an important role in the formation of plasma protein coronas on Fe3O4 NPs; it not only influenced the protein composition of the formed plasma protein corona but also affected the abundances of the plasma proteins within the coronas. Understanding the different binding profiles of human plasma proteins on Fe3O4 NPs of different sizes would facilitate the exploration of the bio-distributions and biological fates of Fe3O4 NPs in biological systems. PMID:24974013

Hu, Zhengyan; Zhang, Hongyan; Zhang, Yi; Wu, Ren'an; Zou, Hanfa

2014-09-01

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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

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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

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ESR on Superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

In this study we have investigated temperature and frequency dependence of magnetic properties of superparamagnetic iron oxide particles (SPION) having a size of 1.1 nm. The polycrystalline powders placed in nonmagnetic paraffin just above its melting temperature, have been tried to orient in the presence of strong magnetic field (15 kg) and cooled down to melting temperature of paraffin. A sample with dimensions 1.5x2x2.5 mm was cut from this ingot and ESR measurements have been carried out in a temperature range of 10-300 K. A single, relatively broad and temperature dependent ESR signal was observed at all measurement temperatures. The linewidth slightly increases with decreasing temperature down to 100 K, then it sharply increases down to 60 K. Below 60 K the trend is reversed and the linewidth start to decrease. The resonance field remains almost constant down to 100 K and decreases sharply as the temperature is decreased further. The ESR spectra of Fe3O4 shows a linear dependence on microwave frequency. By using experimental results, the effective g-value and internal field are deduced as 1.9846 and 40 G, respectively

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Preparation and characterization of PVPI-coated Fe3O4 nanoparticles as an MRI contrast agent  

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Polyvinylpyrrolidone-iodine (PVPI)-coated Fe3O4 nanoparticles were prepared by using inverse chemical co-precipitation method, in which the PVPI serves as a stabilizer and dispersant. The wide angle X-ray diffraction (WAXD) and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that the resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FTIR) results suggested that PVPI interacted with Fe3O4 via its carbonyl groups. Results of superconducting quantum interference device (SQUID) indicated prepared Fe3O4 nanoparticles exhibited superparamagnetic behavior and high saturation magnetization. T2-weighted MRI images of PVPI-coated Fe3O4 nanoparticles showed that the magnetic resonance signal was enhanced significantly with increasing nanoparticles concentration in water at room temperature. These results indicated that the PVPI-coated Fe3O4 nanoparticles had great potential for application in MRI as a T2 contrast agent. - Highlights: • PVPI-coated Fe3O4 nanoparticles were prepared using inverse co-precipitation method. • Resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. • Prepared Fe3O4 nanoparticles exhibited superparamagnetic behavior. • T2-weighted MRI images of PVPI-coated Fe3O4 nanoparticles were obtained

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Adsorption of uranium ions from aqueous solution by amine-group functionalized magnetic Fe3O4 nanoparticle  

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The magnetic Fe3O4 nanoparticle was functionalized by covalently grafting amine group with (3-aminopropyl) trimethoxy silane, and the Fe3O4-NH2 nanoparticle and the Fe3O4 nanoparticle were characterized by Fourier transform infrared, and X-ray diffraction. And the results indicated the amine-group was immobilized successfully on the surface of Fe3O4. The adsorption behavior of uranium from aqueous solution by the Fe3O4 nanoparticle and the Fe3O4-NH2 nanoparticle was investigated using batch experiments. The pH of initial aqueous solution at 5.0 and 6.0 were in favour of adsorption of uranium, and the adsorption percentage of uranium by the Fe3O4 nanoparticle and the Fe3O4-NH2 nanoparticle were 81.2 and 95.6 %, respectively. In addition, the adsorption of uranium ions could be well-described by the Langmuir, Freundlich isotherms and pseudo-second kinetic models. The monolayer adsorption maximum capacity of the Fe3O4 nanoparticle and the Fe3O4-NH2 nanoparticle were 85.35 and 268.49 mg/g at 298.15 K, respectively, which indicate the adsorption capacity the Fe3O4 nanoparticle was improved by amine functionalization. (author)

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Synthesis and characterization of surface-modified Fe3O4 super-paramagnetic nanoparticles.  

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Aqueous dispersion and stability of Fe3O4 nanoparticles remain an issue unresolved since aggregation of naked iron nanoparticles in water. In this study, we successfully synthesized different Fe3O4 super-paramagnetic nanoparticles which were modified by three kinds of materials [DSPE-MPEG2000, TiO2 and poly acrylic acid (PAA)] and further detected their characteristics. Transmission electron microscopy (TEM) clearly showed sizes and morphology of the four kinds of nanoparticles. X-ray diffraction (XRD) proved successfully coating of the three kinds of nanoparticles and their structures were maintained. Vibrating sample magnetometer (VSM) verified that their magnetic properties fitted for the super-paramagnetic function. More importantly, the particle size analysis indicated that Fe3O4@PAA had a better size distribution, biocompatibility, stability and dispersion than the other two kinds of nanoparticles. In addition, using CNE2 cells as a model, we found that all nanoparticles were nontoxic. Taken together, our data suggest that Fe3O4@PAA nanoaparticles are superior in the application of biomedical field among the four kinds of Fe3O4 nanoparticles in the future. PMID:24710944

Zhang, Zhan-jie; Ma, Jia; Xu, Shuang-bing; Ren, Jing-hua; Qin, You; Huang, Jing; Yang, Kun-yu; Zhang, Zhi-ping; Wu, Gang

2014-04-01

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Facilely preparation and microwave absorption properties of Fe3O4 nanoparticles  

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Highlights: ? A bran-new method is firstly used to fabricate Fe3O4 nanoparticles. ? The detailed analysis of formation mechanism is discussed. ? The electromagnetic absorption properties are defined. ? The effect of nanometer-sized is considered for the excellent microwave absorption. - Abstract: The Fe3O4 nanoparticles were prepared by a novel wet-chemical method which shows its highly synthesizing efficiency and controllability. A possible formation mechanism was also proposed to explain the synthesizing process. X-ray diffraction (XRD) and transmission electron microscope (TEM) were employed and yielded an examination of an average diameter of 77 nm of the as-synthesized Fe3O4 nanoparticles with face-centered cubic structure. Vibrating sample magnetometer (VSM) and vector network analyzer were employed to measure the magnetic property and electromagnetic parameters of the nanoparticles, then reflection losses (RL (dB)) were calculated in the frequency range of 2–18 GHz. A large saturation magnetization (72.36 emu/g) and high coercivity (95 Oe) were determined and indicated that the Fe3O4 nanoparticles own strong magnetic performance. Following simulation results showed that the lowest reflection loss of the sample was ?21.2 dB at 5.6 GHz with layer thickness of 6 mm. Effect of nanometer-sized further provided an explanation for the excellent microwave absorption behavior shown by the Fe3O4 nanoparticles

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Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry  

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Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe3O4@Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe3O4@Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe3O4@Au-FA nanoparticles.

Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

2015-02-01

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Synthesis and characterization of Fe3O4 nanoparticles coated with fucan polysaccharides  

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In this work we report the preparation of fucan-coated magnetite (Fe3O4) nanoparticles by the co-precipitation method. These nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Mössbauer spectroscopy and magnetic measurements. The nanoparticles showed quasi-spherical morphology with mean sizes around 10 nm. XRD and FT-IR confirmed the functionalization of the Fe3O4 nanoparticles with the fucan polysaccharide. Room temperature magnetization measurements and Mössbauer spectroscopy showed that the nanoparticles exhibited superparamagnetic behavior at 300 K and the magnetic properties of the Fe3O4 are partly screened by the coating preventing aggregation.

Silva, V. A. J.; Andrade, P. L.; Silva, M. P. C.; Bustamante D., A.; De Los Santos Valladares, Luis; Albino Aguiar, J.

2013-10-01

 
 
 
 
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Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells  

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Full Text Available 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, only at a high concentration (100 ?g/mL; a lower concentration (10 ?g/mL increased the production of reactive oxygen species, increased oxidative damage to DNA, and decreased the level of reduced glutathione. MgNPs-Fe3O4 caused a dose-dependent increase in the CD44+ fraction of A549 cells. MgNPs-Fe3O4 induced the expression of heme oxygenase-1 at a concentration of 1 ?g/mL, and in a dose-dependent manner. Despite these effects, MgNPs-Fe3O4 had minimal effect on cell viability and elicited only a small increase in the number of cells undergoing apoptosis. Together, these data suggest that MgNPs-Fe3O4 exert little or no cytotoxicity until a high exposure level (100 ?g/mL is reached. This dissociation between elevated indices of cell damage and a small effect on cell viability warrants further study.

Hiroshi Kasai

2013-07-01

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

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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

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Monodispersed core-shell Fe3O4(at)Au nanoparticles  

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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

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

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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

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Synthesis and characterization of Fe3O4@ZnS and Fe3O4@Au@ZnS core–shell nanoparticles  

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In the present work we report new assets on the synthesis and characterization of magnetite based core–shell nanoparticles such as Fe3O4@ZnS and Fe3O4@Au@ZnS. The composites were prepared by seed mediated growth which consist in a sequential growth of a second or third component on a preformed magnetite seeds in the presence of sodium laurylsulphate additives with essential role in growth and aggregation of nanoparticles. Evolved gas analysis (EGA) coupled with FT-IR was used in order to evidence the stages of ZnS shell formation. XRD studies were used for the structural characterization while high resolution transmission electron microscopy gave information concerning morphology and size distributions of nanoparticles. Qualitative and quantitative compositional analysis of samples was made by X-ray photoelectron spectroscopy (XPS). All the samples showed magnetic response due to the superparamagnetic behavior of magnetite cores. Increased saturation magnetization was determined for Fe3O4@ZnS samples. A significant photoluminescence (PL) enhancement was also observed as a result of Fe3O4:Zn2+ molar ratio decrease. Additional PL increased response was realized by inserting a gold shell between the magnetite core and ZnS outer shell. Considerations regarding both PL and magnetization enhancements are also presented.

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Synthesis and characterization of Fe3O4@ZnS and Fe3O4@Au@ZnS core-shell nanoparticles  

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In the present work we report new assets on the synthesis and characterization of magnetite based core-shell nanoparticles such as Fe3O4@ZnS and Fe3O4@Au@ZnS. The composites were prepared by seed mediated growth which consist in a sequential growth of a second or third component on a preformed magnetite seeds in the presence of sodium laurylsulphate additives with essential role in growth and aggregation of nanoparticles. Evolved gas analysis (EGA) coupled with FT-IR was used in order to evidence the stages of ZnS shell formation. XRD studies were used for the structural characterization while high resolution transmission electron microscopy gave information concerning morphology and size distributions of nanoparticles. Qualitative and quantitative compositional analysis of samples was made by X-ray photoelectron spectroscopy (XPS). All the samples showed magnetic response due to the superparamagnetic behavior of magnetite cores. Increased saturation magnetization was determined for Fe3O4@ZnS samples. A significant photoluminescence (PL) enhancement was also observed as a result of Fe3O4:Zn2+ molar ratio decrease. Additional PL increased response was realized by inserting a gold shell between the magnetite core and ZnS outer shell. Considerations regarding both PL and magnetization enhancements are also presented.

Stefan, M.; Leostean, C.; Pana, O.; Soran, M.-L.; Suciu, R. C.; Gautron, E.; Chauvet, O.

2014-01-01

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Photo-induced electric polarizability of Fe3O4 nanoparticles in weak optical fields.  

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Using a developed co-precipitation method, we synthesized spherical Fe3O4 nanoparticles with a wide nonlinear absorption band of visible radiation. Optical properties of the synthesized nanoparticles dispersed in an optically transparent copolymer of methyl methacrylate with styrene were studied by optical spectroscopy and z-scan techniques. We found that the electric polarizability of Fe3O4 nanoparticles is altered by low-intensity visible radiation (I ? 0.2 kW/cm2; ? = 442 and 561 nm) and reaches a value of 107 Å3. The change in polarizability is induced by the intraband phototransition of charge carriers. This optical effect may be employed to improve the drug uptake properties of Fe3O4 nanoparticles. PACS: 33.15.Kr78.67.Bf42.70.Nq. PMID:23837726

Milichko, Valentin A; Nechaev, Anton I; Valtsifer, Viktor A; Strelnikov, Vladimir N; Kulchin, Yurii N; Dzyuba, Vladimir P

2013-01-01

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Single source preparation of superparamagnetic Fe3O4 nanoparticles by simple cyclic microwave approach  

International Nuclear Information System (INIS)

Graphical abstract: - Highlights: • Superparamagnetic Fe3O4 nanoparticles were synthesized in high yield. • PEG-200 was applied as both solvent and reductive agent. • Single source synthesis of Fe3O4 was performed. • Nontoxic materials and surfactant were used in current investigation. • Reaction time and temperature significantly decreased in current experiment. - Abstract: Polyol mediated process was applied for the synthesis of Fe3O4 nanoparticles under microwave irradiation. By combination of polyol medium and microwave irradiation different advantages including low reaction time, low consumption of energy, and simplicity were achieved. Different parameters affecting on products including microwave irradiation power, reaction time, reactants concentration, and solvent were changed to reach the optimum condition for synthesis of Fe3O4 nanoparticles. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR) spectra, and vibrating sample magnetometer (VSM). Facile preparation and separation are important features of this route. This work has provided a general, simple, and effective method to control the composition and morphology of Fe3O4 nanoparticles in nonaqueous solution, which will be important for inorganic synthesis methodolog

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Catalytic performance of Fe3O4 nanoparticles for cyclocondensation synthesis of thiacrown ethers  

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The catalytic function of nanoparticles is one the most successful applications of nanotechnologies so far. A novel and mild one-pot cyclocondensation reaction catalyzed by Fe3O4 nanoparticles is achieved for the first time in this work. By the function of those nanoparticles, the thiacrown ethers, including both 1,4-dithiane and 1,4,7-trithiacyclononane were obtained with considerable yield and turnover in a milder condition than that of the conventional routes. The excellent dehydrating ability and acid sensitivity of Fe3O4 nanoparticles were discovered in a series of experiments of esterification of DL-malic acid. The catalytic reaction mechanism of Fe3O4 nanoparticles was explored through the investigation of morphology evolution of those nanoparticles by transmission electron microscopy. Interestingly, the as-prepared big nanoparticles were decomposed into hollow or loose bounded aggregates of smaller nanoparticles after catalytic cycles. The result shown in this work claims promising utilization of Fe3O4 nanoparticles with big potential in catalytic synthesis.

Lin, Shangxin; Chen, Yajie; Tan, Xiepeng; Song, Feng; Yue-Bun Pun, Edwin; He, Zhubing; Pu, Jixiong

2015-01-01

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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

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Preparation and application of core–shell Fe3O4/polythiophene nanoparticles  

International Nuclear Information System (INIS)

The Fe3O4/polythiophene nanoparticles, possessing core–shell structure, were prepared by two-step method. In the first step, the Fe3O4 particles were synthesized via co-precipitation of FeCl3 and FeSO4, using the NH3·H2O and N2H4·H2O as precipitant system. In the second step, the thiophene adsorbed and polymerized on the surface of the Fe3O4 in the solvent of chloroform. Raman, FTIR, EDS, XRD, TEM, Zeta potential measurement and TG-SDTA were employed to characterize the composition and structure of the products. The results showed that the Fe3O4/polythiophene nanoparticles were successfully synthesized with good dispersion and stable core–shell structure, provided with average particle size of approximately 20 nm, in which the diameter of Fe3O4 core was approximately 14 nm and the thickness of polythiophene shell was approximately 3–4 nm. Then, the nanoparticles were added into alkyd varnish to prepare a composite coating. The neutral salt spray test, paraffin control test and mechanical test were carried out to identify the properties of the composite coating. It was found that the composite coating had good performances of anticorrosion and paraffin controlling when the mass fraction of the nanoparticles was 0.8–1 wt% in alkyd varnish. As a multifunctional material, the Femultifunctional material, the Fe3O4/polythiophene nanoparticles can be used in the internal coating of pipeline and have great potential application in crude oil pipeline transportation.

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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

53

Green synthesis and characterization of superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

In this paper, we have first demonstrated a facile and green synthetic approach for preparing superparamagnetic Fe3O4 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 Fe3O4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that Fe3O4 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 Fe3O4 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 Fe3O4 nanoparticles had superparamagnetic properties. Fourier transform infrared spectroscopy (FT-IR) spectrum displayed that troscopy (FT-IR) spectrum displayed that the characteristic band of Fe-O at 569 cm-1 was indicative of Fe3O4. This method might provide a new, mild, green, and economical concept for the synthesis of other nanomaterials.

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Effect of Fe3O4 magnetic nanoparticles on lysozyme amyloid aggregation  

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Peptide amyloid aggregation is a hallmark of several human pathologies termed amyloid diseases. We have investigated the effect of electrostatically stabilized magnetic nanoparticles of Fe3O4 on the amyloid aggregation of lysozyme, as a prototypical amyloidogenic protein. Thioflavin T fluorescence assay and atomic force microscopy were used for monitoring the inhibiting and disassembly activity of magnetic nanoparticles of Fe3O4. We have found that magnetic Fe3O4 nanoparticles are able to interact with lysozyme amyloids in vitro leading to a reduction of the amyloid aggregates, thus promoting depolymerization; the studied nanoparticles also inhibit lysozyme amyloid aggregation. The ability to inhibit lysozyme amyloid formation and promote lysozyme amyloid disassembly exhibit concentration-dependent characteristics with IC50 = 0.65 mg ml-1 and DC50 = 0.16 mg ml-1 indicating that nanoparticles interfere with lysozyme aggregation already at stoichiometric concentrations. These features make Fe3O4 nanoparticles of potential interest as therapeutic agents against amyloid diseases and their non-risk exploitation in nanomedicine and nanodiagnostics.

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Supercritical Carbon Dioxide Anchored Fe3O4 Nanoparticles on Graphene Foam and Lithium Battery Performance.  

Science.gov (United States)

Magnetite (Fe3O4) is an attractive electrode material due to its high theoretical capacity, eco-friendliness, and natural abundance. However, its commercial application in lithium-ion batteries is still hindered by its poor cycling stability and low rate capacity resulting from large volume expansion and low conductivity. We present a new approach which makes use of supercritical carbon dioxide to efficiently anchor Fe3O4 nanoparticles (NPs) on graphene foam (GF), which was obtained by chemical vapor deposition in a single step. Without the use of any surfactants, we obtain moderately spaced Fe3O4 NPs arrays on the surface of GF. The particle size of the Fe3O4 NPs exhibits a narrow distribution (11 ± 4 nm in diameter). As a result, the composites deliver a high capacity of about 1200 mAh g(-1) up to 500 cycles at 1 C (924 mAh g(-1)) and about 300 mAh g(-1) at 20 C, which reaches a record high using Fe3O4 as anode material for lithium-ion batteries. PMID:25438281

Hu, Xuebo; Ma, Minhao; Zeng, Mengqi; Sun, Yangyong; Chen, Linfeng; Xue, Yinghui; Zhang, Tao; Ai, Xinping; Mendes, Rafael G; Rümmeli, Mark H; Fu, Lei

2014-12-24

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The immunotherapeutic effect of Fe3O4 nanoparticles as adjuvants on mice H22 live cancer.  

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The aim of this paper is to prepare Fe3O4 nanoparticles and study its immunotherapeutic effect as adjuvants on mice H22 live cancer. The Fe3O4 nanoparticles were prepared by chemical coprecipitation route. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive Analysis (EDS) were used to characterize Fe3O4 nanoparticles. The Fe3O4 nanoparticles were compared with the common alum adjuvants for its ability to induce immunity to inhibit tumor growth rate by prophylactic and therapeutic studies. Results indicated that Fe3O4 nanopaticles adsorbed autovaccine took great advantages over the common alum adjuvants after subcutaneous injection, raised the mass inhibitory rate of tumor, boosted the activity of cytotoxicity and enhanced the level of IFN-gamma cytokine. Thus, we concluded that Fe3O4 nanoparticles as adjuvants had great potential for enhancing anti-tumor immune response. PMID:20352885

Liu, Hui; Zhanl, Dongsheng; Du, Yiqun

2010-01-01

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Synthesis of Co-Cu-Zn doped Fe3O4 nanoparticles with tunable morphology and magnetic properties  

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Co-Cu-Zn doped Fe3O4 nanoparticles can be successfully synthesized using a simple method. The particles in the size range 20-400 nm with different regular shapes i.e. sphere-like, regular hexane and tetrahedron are controllably achieved by changing the metal ion concentration. Compared to pure Fe3O4 without dopants, Co-Cu-Zn doped Fe3O4 nanoparticles exhibit better microwave absorbing properties at 2-18 GHz. Among three Co-Cu-Zn doped Fe3O4 nanoparticles with different morphologies, tetrahedral Co-Cu-Zn doped Fe3O4 nanoparticles represent a better dielectric loss in high frequency range. This work is believed the first known report of Co-Cu-Zn doped Fe3O4 nanoparticles with tunable morphology and magnetic properties through the hydrothermal process without using any organic solvents, organic metal salts or surfactants.

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Effects of Fe3O4 nanoparticles on secondary structure of cytochrome c by synchrotron radiation circular dichroism spectroscopy  

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Supermagnetic iron oxide nanoparticles (Fe3O-4-NPs) can promote many attractive functions in biomedical fields. In this study,the interaction of Fe3O4NPs (10 nm and 40 nm) with cytochrome c (Cyt c) was studied by synchrotron radiation circular dichroism (SRCD) and UV-Vis spectroscopy. After adding Fe3O4NPs in the Cyt c solution,the intensity of the Soret band (408 nm) decreased significantly. The SRCD characterization showed the loss of the ?-helix structure and the occurrence of cytochrome c unfolding after Fe3O4-NPs treatment, meanwhile, the 10 nm Fe3O4-NPs had more prominent effects than the 40 nm ones. The results showed significant size-depended and dose-depended effects. This study provides important insight into the interaction of Fe3O4NPs with cytochrome c, which may be a useful guideline for further use of Fe3O4NPs. (authors)

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Magneto-elasticity in hydrogels containing Fe3O4 nanoparticles and their potential applications  

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The magnetic hydrogels have been fabricated via standard method of polymer preparation. Hydrogels were the mixture of polyvinyl alcohol (PVA) and water by certain ratio of mass. Magnetism in hydrogels was presented by introduction of magnetic Fe3O4 nanoparticles with crystal size ranging from 11 nm to 15 nm, prepared by coprecipitation technique from iron-sands. According to the magnetic induction experiment, it has shown that the magneto-elasticity of gels containing Fe3O4 of around 2.5% - 15% tends to decrease as increasing Fe3O4 concentration. The magneto-elasticity responses of the gels clearly form hysteresis in the increasing and decreasing applied magnetic field, where in turn open the potential applications of these magnetic hydrogels.

Sunaryono, Taufiq, Ahmad; Munaji, Indarto, Bahtera; Triwikantoro, Zainuri, Mochamad; Darminto

2013-09-01

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Amperometric biosensor for xanthine determination based on Fe3O4 nanoparticles.  

Science.gov (United States)

An amperometric xanthine biosensor was developed based on the immobilization of xanthine oxidase (XO) into the Fe3O4 nanoparticles modified carbon paste. Electron transfer properties of unmodified and Fe3O4 nanoparticles modified carbon paste electrodes were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Fe3O4 nanoparticles increased electroactive surface area of the electrode and electron transfer at solution/electrode interface. Optimum pH, nanoparticle loading and enzyme loading were found to be 6.0; 14.2% and 0.6 Unit XO respectively. Fe3O4 nanoparticles modified carbon paste enzyme electrode allowed xanthine determination at -0.20 V, thus minimizing the potential interferences from electrochemically oxidizable substances such as ascorbic acid and uric acid. A linear relationship was obtained in the concentration range from 7.4 × 10-7 mol L-1 to 7.5 × 10-5 mol L-1 and a detection limit of 2.0 × 10-7 mol L-1. The biosensor was used for determination of xanthine in urine samples and the results indicate that the biosensor is effective for the detection of xanthine. PMID:24664322

Oztürk, Funda Özcan; Erden, P?nar Esra; Kaçar, Ceren; Kiliç, Esma

2014-01-01

 
 
 
 
61

Green synthesis of soya bean sprouts-mediated superparamagnetic Fe3O4 nanoparticles  

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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.

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Synthesis and characterization of monodisperse colloidal spheres of Pb containing superparamagnetic Fe 3O 4 nanoparticles  

Science.gov (United States)

Monodisperse colloidal spheres of Pb embedded with superparamagnetic Fe 3O 4 nanoparticles have been synthesized by refluxing lead acetate in the presence of a magnetite-based ferrofluid in tetra(ethylene glycol), followed by quenching with cold ethanol. Depending on the amounts of ferrofluid and lead acetate fed to the reaction mixture, the molar ratio of encapsulated Fe 3O 4 to Pb could be varied in the range of 0.001-0.06. Both superparamagnetic and superconducting properties were characterized by SQUID measurements. These results demonstrate a simple, solution-phase approach to the controlled synthesis of composite colloidal spheres displaying a combination of superconducting and superparamagnetic properties.

Wang, Yuliang; Herricks, Thurston; Ibisate, Marta; Camargo, Pedro H. C.; Xia, Younan

2007-02-01

63

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

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Orthogonal optimization design for preparation of Fe3O4 nanoparticles via chemical coprecipitation  

International Nuclear Information System (INIS)

Fe3O4 nanoparticles ranging from 8.9 to 12.2 nm were prepared by chemical coprecipitation based on L16(45) orthogonal experiments. The effects of five process parameters (pH, Fe2+/Fe3+ ratio, reaction temperature, ferric salt concentration, and crystallization temperature) on particle size and specific saturation magnetization of Fe3O4 nanoparticles were investigated. The micro-morphology, crystal structure, specific saturation magnetization, and surface properties were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), vibration magnetometer (VSM), and Fourier infrared (FT-IR). The results indicate that Fe2+/Fe3+ ratio and pH are the main factors affecting particle size and specific saturation magnetization, respectively. The Fe3O4 nanoparticles are mostly spherical powders with a narrow size distribution and a high purity. The Fe3O4 nanoparticles can achieve high dispersion performance and suspension stability by in situ dispersion with double adsorption layers.

65

Orthogonal optimization design for preparation of Fe3O4 nanoparticles via chemical coprecipitation  

Science.gov (United States)

Fe3O4 nanoparticles ranging from 8.9 to 12.2 nm were prepared by chemical coprecipitation based on L16(45) orthogonal experiments. The effects of five process parameters (pH, Fe2+/Fe3+ ratio, reaction temperature, ferric salt concentration, and crystallization temperature) on particle size and specific saturation magnetization of Fe3O4 nanoparticles were investigated. The micro-morphology, crystal structure, specific saturation magnetization, and surface properties were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), vibration magnetometer (VSM), and Fourier infrared (FT-IR). The results indicate that Fe2+/Fe3+ ratio and pH are the main factors affecting particle size and specific saturation magnetization, respectively. The Fe3O4 nanoparticles are mostly spherical powders with a narrow size distribution and a high purity. The Fe3O4 nanoparticles can achieve high dispersion performance and suspension stability by in situ dispersion with double adsorption layers.

Meng, Haining; Zhang, Zhenzhong; Zhao, Fangxia; Qiu, Tai; Yang, Jingdong

2013-09-01

66

Fabrication of docetaxel surfaced Fe3O4 magnetite nanoparticles and their cytotoxicity on 4?T1 breast cancer cells  

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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...

Mh, Yazdi; Najafi Niazzadeh, Z.; Khorramizadeh MR; Amini, M.; Ar, Shahverdi

2012-01-01

67

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

68

Simple polyol route to synthesize heptanoic acid coated magnetite (Fe3O4) nanoparticles  

International Nuclear Information System (INIS)

Highlights: ? Heptanoic acid@Fe3O4 nanocomposite has been prepared via simple polyol. ? Heptanoic acid used as both surfactant and solvents. ? Magneto polymer composite with adjustable Ea has a potential usage as functional composites. - Abstract: Magnetite (Fe3O4) nanoparticles were prepared via polyol method by using FeCl2 as only source of iron. As-prepared samples were characterized by powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analyzer (TGA) and vibrating sample magnetometer (VSM). Crystalline phase was identified as Fe3O4 and the crystallite sizes were calculated as 19.1 ± 1.1 and 22 ± 1.3 nm for uncalcinated and calcinated products from X-ray line profile fitting. The capping of heptanoic acid around Fe3O4 nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygen's of the carboxylate and the nanoparticle surface and also by TG analysis. VSM measurements showed that both samples exhibited typical superparamagnetic behavior at room temperature with different Ms values. The ?? decreases with increasing frequency for both composites and permeability has almost same values for all temperatures at higher frequencies. As synthesized and calcinated samples conductivity increase linearly with the temperature

69

Synthesis and Properties of Fe3O4 Nanoparticles by Co-precipitation Method to Removal Procion Dye  

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Fe3O4 (magnetite) nanoparticles were synthesized by chemical co-precipitation method. The structure, morphology and magnetic properties of as-prepared were characterized by X Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X Ray Spectrometry (SEM-EDS), Transmission Electron Microscope (TEM) and Vibrating Sample Magnetometer (VSM). The result of XRD characterization was indicated Fe3O4 as the product. SEM and TEM image of the Fe3O4 showed nanoparticles Fe3O4 have the mean...

Poedji Loekitowati Hariani; Muhammad Faizal; Ridwan; Marsi; Dedi Setiabudidaya

2013-01-01

70

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 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.

71

A facile strategy to synthesize monodisperse superparamagnetic OA-modified Fe3O4 nanoparticles with PEG assistant  

Science.gov (United States)

A facile strategy was reported to synthesize monodisperse super-paramagnetic oleic acid (OA) modified Fe3O4 nanoparticles, which the poly ethylene glycol (PEG) was used as the assistant. The influence of the molecular weight and concentration of PEG was investigated in the process of OA-modification. In addition, the mechanism of PEG action in the reaction system was discussed. The morphology and properties of the as-synthesized Fe3O4 magnetic nanoparticles were characterized by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and superconducting quantum interference device (SQUID). The size (12 nm) of the as-prepared Fe3O4 nanoparticles is smaller than the superparamagnetic critical size (25 nm) of Fe3O4 nanoparticles, which endows the OA-modified Fe3O4 nanoparticles with superparamagnetic property. Furthermore, the dispersibility and stability of as-synthesized OA-modified Fe3O4 magnetic nanoparticles were very good. As the stabilizer and dispersant, PEG played a very important role and did not encapsulate the OA-modified Fe3O4 nanoparticles. The condition for OA-modified Fe3O4 nanoparticles preparation was optimized.

Sun, Minmin; Zhu, Aimei; Zhang, Qiugen; Liu, Qinglin

2014-11-01

72

Preparation and characterization of spindle-like Fe3O4 mesoporous nanoparticles  

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Full Text Available Abstract 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-desorption analysis techniques. The results show that ?-Fe2O3 phase transformed into Fe3O4 phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe3O4 mesoporous NPs possess high Brunauer-Emmett-Teller (BET surface area up to ca. 7.9 m2 g-1. In addition, the Fe3O4 NPs present higher saturation magnetization (85.2 emu g-1 and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology.

Zhang Shaofeng

2011-01-01

73

One-step hydrothermal synthesis of magnetic Fe3O4 nanoparticles immobilized on polyamide fabric  

International Nuclear Information System (INIS)

A thin film of nanosized Fe3O4 particles prepared by hydrothermal method was immobilized on the surface of polyamide 6 fiber using ferric trichloride and ferrous chloride as the precursor, N,N-dimethyl formamide as the swelling agent and sodium dodecyl sulfate as the dispersant agent. The morphology, crystalline phase, thermal stability, magnetization properties and chemical structure of polyamide 6 fabric before and after treatments were characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), vibrating sample magnetometer (VSM) and X-ray photoelectron spectroscopy (XPS) techniques. The tensile properties and abrasion resistance were also measured. It was found that the inverse cubic spinel phase of Fe3O4 nanoparticles with an average size 50 nm were synthesized, and synchronously grafted onto polyamide fiber surface. As compared with the original fabric, the onset decomposition temperature of the Fe3O4-coated fabric decreased slightly. The saturation magnetization was measured to be 3.8 emu/g at temperature of 300 K. The tensile properties were enhanced to some extent mainly due to the fabric shrinkage. The abrasion resistance of the Fe3O4-coated fabric behaved well.

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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.

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Stability and magnetically induced heating behavior of lipid-coated Fe3O4 nanoparticles  

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Magnetic nanoparticles that are currently explored for various biomedical applications exhibit a high propensity to minimize total surface energy through aggregation. This study introduces a unique, thermoresponsive nanocomposite design demonstrating substantial colloidal stability of superparamagnetic Fe3O4 nanoparticles (SPIONs) due to a surface-immobilized lipid layer. Lipid coating was accomplished in different buffer systems, pH 7.4, using an equimolar mixture of 1,2-dipalmitoyl-sn-glyce...

Allam, Ayat A.; Sadat, Md Ehsan; Potter, Sarah J.; Mast, David B.; Mohamed, Dina F.; Habib, Fawzia S.; Pauletti, Giovanni M.

2013-01-01

76

DBT degradation enhancement by decorating Rhodococcus erythropolis IGST8 with magnetic Fe3O4 nanoparticles  

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Biodesulfurization (BDS) of dibenzothiophene (DBT) was carried out by Rhodococcus erythropolis IGST8 decorated with magnetic Fe3O4 nanoparticles, synthesized in-house by a chemical method, with an average size of 45-50 nm, in order to facilitate the post-reaction separation of the bacteria from the reaction mixture. Scanning electron microscopy (SEM) showed that the magnetic nanoparticles substantially coated the surfaces of the bacteria. It was found that the decorated cells had a 56% higher...

Ansari, Farahnaz; Grigoriev, P.; Libor, S.; Tothill, Ibtisam E.; Ramsden, Jeremy J.

2009-01-01

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Synthesis and characterization of multifunctional Fe3O4/poly(fluorescein O-methacrylate) core/shell nanoparticles.  

Science.gov (United States)

Multifunctional fluorescent and superparamagnetic Fe(3)O(4)/poly(fluorescein O-methacrylate) [Fe(3)O(4)/poly(FMA)] nanoparticles with core/shell structure were synthesized via surface-initiated polymerization. First, polymerizable double bonds were introduced onto the surface of Fe(3)O(4) nanoparticles via ligand exchange and a condensation reaction. A fluorescent monomer, FMA, was then polymerized to the double bonds at the surface via free-radical polymerization, leading to form a fluorescent polymer shell around the superparamagnetic Fe(3)O(4) core. The resultant Fe(3)O(4)/poly(FMA) nanoparticles were characterized by Fourier transform infrared, nuclear magnetic resonance, and X-ray diffraction spectroscopy to confirm the reactions. Transmission electron microscopy images showed that the Fe(3)O(4)/poly(FMA) nanoparticles have a spherical and monodisperse core/shell morphology. Photoluminescence spectroscopy and superconducting quantum interference device magnetometer analyses confirmed that the Fe(3)O(4)/poly(FMA) nanoparticles exhibited fluorescent and superparamagnetic properties, respectively. In addition, we demonstrated the potential bioimaging application of the Fe(3)O(4)/poly(FMA) nanoparticles by visualizing the cellular uptake of the nanoparticles into A549 lung cancer cells. PMID:22613627

Govindaiah, Patakamuri; Hwang, Taewon; Yoo, Hyunhee; Kim, Yong Seok; Lee, Sun Jong; Choi, Sung Wook; Kim, Jung Hyun

2012-08-01

78

Aloe vera plant-extracted solution hydrothermal synthesis and magnetic properties of magnetite (Fe3O4) nanoparticles  

Science.gov (United States)

Magnetite (Fe3O4) nanoparticles have been successfully synthesized by a novel hydrothermal method using ferric acetylacetonate (Fe(C5H8O2)3) and aloe vera plant-extracted solution. The influences of different reaction temperatures and times on the structure and magnetic properties of the synthesized Fe3O4 nanoparticles were investigated. The synthesized nanoparticles are crystalline and have particle sizes of ˜6-30 nm, as revealed by transmission electron microscopy (TEM). The results of X-ray diffraction (XRD), High resolution TEM (HRTEM) and selected area electron diffraction (SAED) indicate that the synthesized Fe3O4 nanoparticles have the inverse cubic spinel structure without the presence of any other phase impurities. The hysteresis loops of the Fe3O4 nanoparticles at room temperature show superparamagnetic behavior and the saturation magnetization of the Fe3O4 samples increases with increasing reaction temperature and time.

Phumying, Santi; Labuayai, Sarawuth; Thomas, Chunpen; Amornkitbamrung, Vittaya; Swatsitang, Ekaphan; Maensiri, Santi

2013-06-01

79

Interactions in ?-Fe2O3 and Fe3O4 nanoparticle systems  

Science.gov (United States)

We have investigated interaction effects in two different systems of iron oxide nanoparticles. Samples of ?-Fe2O3 and Fe3O4 nanoparticles were synthesized using a matrix-mediated precipitation reaction and a chemical co-precipitation technique respectively. The structural properties of these nanoparticles were studied using x-ray diffraction and transmission electron microscopy. We also used temperature dependent ac magnetic susceptibility measurements to carefully investigate the interactions among these nanoparticles. Our analysis showed that the characteristic interaction energy does not depend simply on the average spacing between the nanoparticles but is likely to be strongly influenced by the fluctuations in the nanoparticle distribution.

Laha, S. S.; Tackett, R. J.; Lawes, G.

2014-09-01

80

Microwave synthesis of magnetic Fe 3O 4 nanoparticles used as a precursor of nanocomposites and ferrofluids  

Science.gov (United States)

Methods to synthesize magnetic Fe 3O 4 nanoparticles and to modify the surface of particles are presented in the present investigation. Fe 3O 4 magnetic nanoparticles were prepared by the co-precipitation of Fe 3+ and Fe 2+, NH 3·H 2O was used as the precipitating agent to adjust the pH value, and the aging of Fe 3O 4 magnetic nanoparticles was accelerated by microwave (MW) irradiation. The obtained Fe 3O 4 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 Fe 3O 4 crystallites was found to be around 8-9 nm. Thereafter, the surface of Fe 3O 4 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 Fe 3O 4 nanoparticles and carboxyl groups of stearic acid, which changed the polarity of Fe 3O 4 nanoparticles. The dispersion of Fe 3O 4 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, Fe 3O 4/polystyrene (PS) nanocomposite was synthesized by adding surface modified Fe 3O 4 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 Fe 3O 4 nanoparticles. The Fe 3O 4 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 4.46×10 -8 and saturated magnetization of 6.56 emu/g. In addition, the mean size d (0.99) of magnetic Fe 3O 4 nanoparticles in the fluid was 36.19 nm.

Hong, R. Y.; Pan, T. T.; Li, H. Z.

2006-08-01

 
 
 
 
81

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 c 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

82

Fe3O4-nanoparticles within porous silicon: Magnetic and cytotoxicity characterization  

Science.gov (United States)

The magnetic properties of porous silicon/Fe3O4 composites are investigated with respect to the adjustability of the blocking temperature along with an evaluation of any size-dependent changes in cytocompatibility. Fe3O4-nanoparticles have been infiltrated within mesoporous silicon, resulting in a system with tunable magnetic properties due to the matrix-morphology, the loading of the nanoparticles, and their size. In order to provide basic information regarding its suitability as a therapeutic platform, the cytotoxicity of these composites have been investigated by a trypan blue exclusion assay with respect to human embryonic kidney 293 cells, and the results compared with cell-only and known cytotoxic controls.

Granitzer, P.; Rumpf, K.; Tian, Y.; Akkaraju, G.; Coffer, J.; Poelt, P.; Reissner, M.

2013-05-01

83

Biocompatibility of Fe3O4@Au composite magnetic nanoparticles in vitro and in vivo  

Directory of Open Access Journals (Sweden)

Full Text Available Yuntao Li1,2, Jing Liu1, Yuejiao Zhong3, Jia Zhang1, Ziyu Wang1, Li Wang1, Yanli An1, Mei Lin1, Zhiqiang Gao2, Dongsheng Zhang11School of Medicine, Southeast University, Nanjing, Jiangsu Province, People's Republic of China; 2Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, People's Republic of China; 3Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research, Nanjing, Jiangsu Province, People's Republic of ChinaPurpose: This research was conducted to assess the biocompatibility of the core-shell Fe3O4@Au composite magnetic nanoparticles (MNPs, which have potential application in tumor hyperthermia. Methods: Fe3O4@Au composite MNPs with core-shell structure were synthesized by reduction of Au3+ in the presence of Fe3O4-MNPs prepared by improved co-precipitation. Cytotoxicity assay, hemolysis test, micronucleus (MN assay, and detection of acute toxicity in mice and beagle dogs were then carried out.Results: The result of cytotoxicity assay showed that the toxicity grade of this material on mouse fibroblast cell line (L-929 was classified as grade 1, which belongs to no cytotoxicity. Hemolysis rates showed 0.278%, 0.232%, and 0.197%, far less than 5%, after treatment with different concentrations of Fe3O4@Au composite MNPs. In the MN assay, there was no significant difference in MN formation rates between the experimental groups and negative control (P > 0.05, but there was a significant difference between the experimental groups and the positive control (P < 0.05. The median lethal dose of the Fe3O4@Au composite MNPs after intraperitoneal administration in mice was 8.39 g/kg, and the 95% confidence interval was 6.58-10.72 g/kg, suggesting that these nanoparticles have a wide safety margin. Acute toxicity testing in beagle dogs also showed no significant difference in body weight between the treatment groups at 1, 2, 3, and 4 weeks after liver injection and no behavioral changes. Furthermore, blood parameters, autopsy, and histopathological studies in the experimental group showed no significant difference compared with the control group.Conclusion: The results indicate that Fe3O4@Au composite MNPs appear to be highly biocompatible and safe nanoparticles that are suitable for further application in tumor hyperthermia. Keywords: toxicity, hyperthermia, core-shell

Li Y

2011-11-01

84

Hydrothermal synthesis, off-axis electron holography and magnetic properties of Fe3O4 nanoparticles  

Science.gov (United States)

The hydrothermal synthesis of Fe3O4 nanoparticles (NPs) (FeCl3 / FeCl2 precursor solution at pH ~ 12 has been confirmed using complementary characterisation techniques of transmission electron microscopy and X-ray diffractometry. Off-axis electron holography allowed for visualisation of their single domain (SD) nature, as well as inter-particle interactions, with the latter attributed to explain the pseudo-SD/multi-domain behaviour demonstrated by bulk magnetic measurements.

Almeida, Trevor P.; Muxworthy, Adrian R.; Williams, Wyn; Kasama, Takeshi; Dunin-Borkowski, Rafal E.

2014-06-01

85

Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have studied the magnetic behavior of dextran-coated magnetite (Fe$_3$O$_4$) nanoparticles with median particle size $\\left=8$ $nm$. Magnetization curves and in-field M\\"ossbauer spectroscopy measurements showed that the magnetic moment $M_S$ of the particles was much smaller than the bulk material. However, we found no evidence of magnetic irreversibility or non-saturating behavior at high fields, usually associated to spin canting. The values of magnetic anisot...

Lima Jr, E.; Brandl, A. L.; Arelaro, A. D.; Goya, G. F.

2005-01-01

86

Magnetic Hyperthermia with Fe3O4 nanoparticles: the Influence of Particle Size on Energy Absorption  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have studied the magnetic and power absorption properties of a series of magnetic nanoparticles (MNPs) of Fe3O4 with average sizes ranging from 3 to 26 nm. Heating experiments as a function of particle size revealed a strong increase in the specific power absorption (SPA) values for particles with = 25-30 nm. On the other side saturation magnetization MS values of these MNPs remain essentially constant for particles with above 10 nm, suggesting that the absorp...

Goya, Gerardo F.; Lima, Jr; Arelaro, Amanda D.; Torres, Teobaldo E.; Rechenberg, Hercilio R.; Rossi, Liane; Marquina, Clara; Ibarra, M. Ricardo

2013-01-01

87

Fe3O4 nanoparticles and nanocomposites with potential application in biomedicine and in communication technologies: Nanoparticle aggregation, interaction, and effective magnetic anisotropy  

Science.gov (United States)

Magnetite nanoparticles with a size of 5-6 nm with potential impact on biomedicine and information/communication technologies were synthesized by thermal decomposition of Fe(acac)3 and subsequently coated with a silica shell exploiting a water-in-oil synthetic procedure. The as-produced powders (comprised of either Fe3O4 or Fe3O4@silica nanoparticles) were mixed with a photocurable resin obtaining two magnetic nanocomposites with the same nominal amount of magnetic material. The static magnetic properties of the two nanopowders and the corresponding nanocomposites were measured in the 10 K-300 K temperature range. Magnetic measurements are shown here to be able to give unambiguous information on single-particle properties such as particle size and magnetic anisotropy as well as on nanoparticle aggregation and interparticle interaction. A comparison between the size distribution functions obtained from magnetic measurements and from TEM images shows that figures estimated from properly analyzed magnetic measurements are very close to the actual values. In addition, the present analysis allows us to determine the value of the effective magnetic anisotropy and to estimate the anisotropy contribution from the surface. The Field-cooled/zero field cooled curves reveal a high degree of particle aggregation in the Fe3O4 nanopowder, which is partially reduced by silica coating and strongly decreased by dissolution in the host polymer. In all considered materials, the nanoparticles are magnetically interacting, the interaction strength being a function of nanoparticle environment and being the lowest in the nanocomposite containing bare, well-separate Fe3O4 particles. All samples behave as interacting superparamagnetic materials instead of ideal superparamagnets and follow the corresponding scaling law.

Allia, P.; Barrera, G.; Tiberto, P.; Nardi, T.; Leterrier, Y.; Sangermano, M.

2014-09-01

88

Potentiometric glucose biosensor based on core-shell Fe3O4-enzyme-polypyrrole nanoparticles.  

Science.gov (United States)

Core-shell Fe3O4-enzyme-polypyrrole (Ppy) nanoparticles with excellent magnetism and conductivity were successfully prepared via the surface modification and enzyme self-encapsulation within Ppy. A novel potentiometric glucose biosensor has been constructed by effectively attaching the proposed Fe3O4-enzyme-Ppy nanoparticles to the surface of the magnetic glassy carbon electrode (MGCE). The optimum biosensing conditions could be provided with polymerization time of pyrrole for 6h and 0.42 mg immobilization amount of Fe3O4-enzyme-Ppy nanoparticles on MGCE. The performance of the developed glucose biosensor was evaluated and the results indicated that a sensitive glucose biosensor could be fabricated. The obtained glucose biosensor presents shorter response time (6 s), wider linear range (0.5 ?M to 34 mM), lower limit of detection (LOD, 0.3 ?M), high-selectivity monitoring of glucose and good stability (with about 98.1% of the initial response signal retained after 20 days). The analytical application of the glucose biosensor confirms the feasibility of glucose detection in serum sample. PMID:23974157

Yang, Zhengpeng; Zhang, Chunjing; Zhang, Jianxin; Bai, Wanbei

2014-01-15

89

Synthesis and characterization of Fe3O4–TiO2 core-shell nanoparticles  

International Nuclear Information System (INIS)

Composite core-shell nanoparticles may have morpho-structural, magnetic, and optical (photoluminescence (PL)) properties different from each of the components considered separately. The properties of Fe3O4–TiO2 nanoparticles can be controlled by adjusting the titania amount (shell thinness). Core–shell nanoparticles were prepared by seed mediated growth of semiconductor (TiO2) through a modified sol-gel process onto preformed magnetite (Fe3O4) cores resulted from the co-precipitation method. The structure and morphology of samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), and high resolution-TEM respectively. X-ray photoelectron spectroscopy was correlated with ICP-AES. Magnetic measurements, optical absorption spectra, as well as PL spectroscopy indicate the presence of a charge/spin transfer from the conduction band of magnetite into the band gap of titania nanocrystals. The process modifies both Fe3O4 and TiO2 magnetic and optical properties, respectively.

90

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

91

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

92

Electrospun magnetic poly(L-lactide) (PLLA) nanofibers by incorporating PLLA-stabilized Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Magnetic poly(L-lactide) (PLLA)/Fe3O4 composite nanofibers were prepared with the purpose to develop a substrate for bone regeneration. To increase the dispersibility of Fe3O4 nanoparticles (NPs) in the PLLA matrix, a modified chemical co-precipitation method was applied to synthesize Fe3O4 NPs in the presence of PLLA. Trifluoroethanol (TFE) was used as the co-solvent for all the reagents, including Fe(II) and Fe(III) salts, sodium hydroxide, and PLLA. The co-precipitated Fe3O4 NPs were surface-coated with PLLA and demonstrated good dispersibility in a PLLA/TFE solution. The composite nanofiber electrospun from the solution displayed a homogeneous distribution of Fe3O4 NPs along the fibers using various contents of Fe3O4 NPs. X-ray diffractometer (XRD) and vibration sample magnetization (VSM) analysis confirmed that the co-precipitation process had minor adverse effects on the crystal structure and saturation magnetization (Ms) of Fe3O4 NPs. The resulting PLLA/Fe3O4 composite nanofibers showed paramagnetic properties with Ms directly related to the Fe3O4 NP concentration. The cytotoxicity of the magnetic composite nanofibers was determined using in vitro culture of osteoblasts (MC3T3-E1) in extracts and co-culture on nanofibrous matrixes. The PLLA/Fe3O4 composite nanofibers did not show significant cytotoxicity in comparison with pure PLLA nanofibers. On the contrary, they demonstrated enhanced effects on cell attachment and proliferation with Fe3O4 NP incorporation. The results suggested that this modified chemical co-precipitation method might be a universal way to produce magnetic biodegradable polyester substrates containing well-dispersed Fe3O4 NPs. This new strategy opens an opportunity to fabricate various kinds of magnetic polymeric substrates for bone tissue regeneration. Highlights: • Polylactide coated Fe3O4 nanoparticles were synthesized by co-precipitation. • The co-precipitated Fe3O4 nanoparticles dispersed well in polylactide nanofibers. • Magnetic polylactide/Fe3O4 nanofibers are good substrates for osteoblasts

93

Study on electric field induced structural color change of Fe3O4@C hybrid nanoparticles  

Science.gov (United States)

The photonic properties of Fe3O4@C and Fe3O4 colloidal suspensions in an external electric field have been investigated. Compared to Fe3O4, the Fe3O4@C colloidal suspension has been found to have a wider tunability range of the optical spectrum and a stronger electric response in low electric fields. Based on the dielectric spectroscopy analysis of Fe3O4@C and Fe3O4 colloidal suspensions, a dielectric loss model has been proposed to explain the significant effect of the carbon shell on the electrically modulated photonic property of the Fe3O4@C suspension.

Zhang, Jianfei; Sun, Aihua; Qiao, Xuanxuan; Chu, Chengyi; Wang, Chongyang; Chen, Tao; Guo, Jianjun; Xu, Gaojie

2014-12-01

94

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with ‘tetrapod’ morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m2 kg?1), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis. (paper)

95

Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles  

CERN Document Server

We have studied the magnetic behavior of dextran-coated Fe3O4 nanoparticles with median particle size = 8 nm. The magnetic anisotropy Ea of the particles was calculated from magnetization and ac susceptibility data. The resulting values correspond to the magnetocrystalline contribution of the high-temperature cubic phase with easy magnetic direction [111], without any additional contributions from particle surface, shape or exchange origin. The resulting values are incompatible with the uniaxial anisotropy of the low-temperature crystal structure of Fe3O4, suggesting that the high-temperature cubic structure is preserved below the Verwey transition in nanometric particles. Accordingly, fully oriented particles showed a continuous decrease of the M(T) curves, without discontinuities at TV . The thermal dependence of the hyperfine field B_hyp(T) was fitted by a simple model of collective magnetic excitations to calculate the single-particle magnetic anisotropy energy Ea. The resulting values give further suppo...

Lima, E; Arelaro, A D; Goya, G F

2006-01-01

96

Porous Fe3O4 nanoparticles: synthesis and application in catalyzing epoxidation of styrene.  

Science.gov (United States)

A facile route was employed to synthesize porous magnetite via reaction of FeCl(3)·6H(2)O with N(2)H(4)·H(2)O in ethylene glycol without any structure-directing agent. The resultant Fe(3)O(4) particles were characterized by transmission electron microscopy, N(2) adsorption, X-ray photoelectron spectroscopy, and thermal gravimetric analysis. It was demonstrated that the particle size varied in the range of 40-220 nm, and the pore size of particles was centered around 2 nm. The gases produced in the formation process of the particles played key role in the formation of the porous structure. The obtained porous magnetite was used as support to immobilize Au nanoparticles with size less than 2 nm with the assistance of L-cysteine. The as-prepared Fe(3)O(4) particles can effectively catalyze epoxidation of styrene, and the immobilization of Au nanoparticles on the Fe(3)O(4) support significantly improved the activity of the catalyst. PMID:21944058

Huang, Changliang; Zhang, Hongye; Sun, Zhenyu; Zhao, Yanfei; Chen, Sha; Tao, Ranting; Liu, Zhimin

2011-12-15

97

[Adsorption of methylene blue from aqueous solution onto magnetic Fe3O4/ graphene oxide nanoparticles].  

Science.gov (United States)

A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe3O4/graphene oxide (Fe3O4/ GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe3O4/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg.g-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment. PMID:25055670

Chang, Qing; Jiang, Guo-Dong; Hu, Meng-Xuan; Huang, Jia; Tang, He-Qing

2014-05-01

98

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

International Nuclear Information System (INIS)

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.

99

Linear birefringence and dichroism measurement in oil-based Fe3O4 magnetic nanoparticles  

International Nuclear Information System (INIS)

To prepare dispersed Fe3O4 magnetic nanoparticles (MNPs), we adopt a co-precipitation method and consider surfactant amount, stirring speed, dispersion mode, and molar ratio of Fe3+/Fe2+. Via transmission electronic microscopy and X-ray diffractometry, we characterize the dispersibility and size of the products and determine the appropriate values of experimental parameters. The stirring speed is 1000 rpm in titration. There is simultaneous ultrasonic vibration and mechanical stirring in the titration and surface coating processes. The surfactant amount of oleic acid is 1.2 ml for molar ratios of Fe3+/Fe2+ as 1.7:1, 1.8:1, and 1.9:1. The average diameters of these Fe3O4 MNPs are 11 nm, and the ratios of saturation magnetization for these MNPs to that of bulk magnetite range from 45% to 65%, with remanent magnetization close to zero and low coercivity. Above all, the linear birefringence and dichroism measurements of the kerosene-based ferrofluid (FF) samples are investigated by a Stokes polarimeter. The influences of particle size distribution and magnetization in the birefringence and dichroism measurements of FFs are discussed. - Highlights: ? Dispersed Fe3O4 magnetic nanoparticles (MNPs) are produced by a co-precipitation method. ? Simultaneous ultrasonic vibration and mechanical stirring are used in titration and coating. ? Diameters of Fe3O4 MNPs are determined as 11 nm with maximum magnetization as 54.27 emu/g. ? Birefringence and dichroism of ferrofluids are obtained by a Stokes polarimeter successfully

100

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

 
 
 
 
101

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

Science.gov (United States)

In this work, we study the preparation and properties of bio-compatible magnetic nanoparticles for immunoassay and DNA detection. The magnetite (Fe 3O 4) 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.

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

2006-09-01

102

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

103

Chromium (VI) reduction in aqueous solutions by Fe3O4-stabilized Fe0 nanoparticles  

International Nuclear Information System (INIS)

This paper describes the use of highly reactive magnetite (Fe3O4) nanoparticles-stabilized Fe0 nanocomposites for the reduction and mitigation of hexavalent chromium Cr(VI) species in aqueous solutions. Higher proportions of Fe3O4 in the nanocomposites could increase the rate of Cr(VI) reduction. In the absence of magnetite, the Cr(VI) mitigation rate was just 51.4% after 60 min of reaction, while with an initial Fe3O4 mass loading of 3 g l-1, the Cr(VI) mitigation rate was nearly 100% after 60 min. The optimal ratio of Fe3O4:Fe0 for the mitigation of Cr(VI) was found to be 40:1. Otherwise, solution pHs significantly affected the rate of Cr(VI) reduction, with reactions occurring more rapidly under acidic or neutral than basic conditions. It is hypothesized that the high efficiency of the Fe3O4 nanoparticles-stabilized Fe0 nanocomposites for Cr(VI) reduction was a direct result of the attachment of Fe0 nanoparticles to the surface of magnetite, which prevents the aggregation of nano-Fe0, moreover, the electron transfer during the reduction process most likely takes place via Fe0 nanoparticles that are located at the magnetite octahedral sites, which are versatile redox centers as they can accommodate both Fe(III) and Fe(II), and this will promote the reduction of Cr(VI). Cr(VI) reductote the reduction of Cr(VI). Cr(VI) reduction is coupled with nano-Fe0 oxidation. Nano-Fe0 particles are located at the magnetite octahedral sites. Ions of Fe(II) and Fe(III) accommodated by magnetite octahedral sites are products of nano-Fe0 oxidation. Therefore, Cr(VI) reduction is mediated either by nano-Fe0 (direct reduction) or Fe(II) species (indirect reduction). Additionally, catalytic Cr(VI) reduction by molecular H2 (or atomic H) is possible.

104

Preparation and characterization of PVPI-coated Fe3O4 nanoparticles as an MRI contrast agent  

Science.gov (United States)

Polyvinylpyrrolidone-iodine (PVPI)-coated Fe3O4 nanoparticles were prepared by using inverse chemical co-precipitation method, in which the PVPI serves as a stabilizer and dispersant. The wide angle X-ray diffraction (WAXD) and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that the resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FTIR) results suggested that PVPI interacted with Fe3O4 via its carbonyl groups. Results of superconducting quantum interference device (SQUID) indicated prepared Fe3O4 nanoparticles exhibited superparamagnetic behavior and high saturation magnetization. T2-weighted MRI images of PVPI-coated Fe3O4 nanoparticles showed that the magnetic resonance signal was enhanced significantly with increasing nanoparticles concentration in water at room temperature. These results indicated that the PVPI-coated Fe3O4 nanoparticles had great potential for application in MRI as a T2 contrast agent.

Wang, Guangshuo; Chang, Ying; Wang, Ling; Wei, Zhiyong; Kang, Jianyun; Sang, Lin; Dong, Xufeng; Chen, Guangyi; Wang, Hong; Qi, Min

2013-08-01

105

Synthesis and characterization of Fe3O4 nanoparticles with perspectives in biomedical applications  

International Nuclear Information System (INIS)

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 some 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 Moessbauer 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. (author)

106

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.

2014-06-01

107

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.

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

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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 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

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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  

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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 nano...

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

2010-01-01

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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. - Hell 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.

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Synthesis and Properties of Fe3O4 Nanoparticles by Co-precipitation Method to Removal Procion Dye  

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Full Text Available Fe3O4 (magnetite nanoparticles were synthesized by chemical co-precipitation method. The structure, morphology and magnetic properties of as-prepared were characterized by X Ray Diffraction (XRD, Scanning Electron Microscope-Energy Dispersive X Ray Spectrometry (SEM-EDS, Transmission Electron Microscope (TEM and Vibrating Sample Magnetometer (VSM. The result of XRD characterization was indicated Fe3O4 as the product. SEM and TEM image of the Fe3O4 showed nanoparticles Fe3O4 have the mean diameter 5-20 nm. The EDS spectra showed strong peaks of Fe and O. Magnetic characteristic of Fe3O4 nanoparticles was indicated super paramagnetic properties. The saturation magnetic was 89.46 emu g-1. Therefore, the nanoparticles Fe3O4 is suitable to remove dye in the water by a simple magnetic separation process. The optimum adsorption occurred at initial concentration of procion dye 100 mg L-1, pH solution 6, dosage of Fe3O4 0.8 g L-1 and contact time 30 minutes under room temperature with color removal 24.40 % and adsorption capacity was 30.503 mg g-1.

Poedji Loekitowati Hariani

2013-06-01

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Multifunctional NaYF4:Yb, Er@mSiO2@Fe3O4-PEG nanoparticles for UCL/MR bioimaging and magnetically targeted drug delivery.  

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A low toxic multifunctional nanoplatform, integrating both mutimodal diagnosis methods and antitumor therapy, is highly desirable to assure its antitumor efficiency. In this work, we show a convenient and adjustable synthesis of multifunctional nanoparticles NaYF4:Yb, Er@mSiO2@Fe3O4-PEG (MFNPs) based on different sizes of up-conversion nanoparticles (UCNPs). With strong up-conversion fluorescence offered by UCNPs, superparamagnetism properties attributed to Fe3O4 nanoparticles and porous structure coming from the mesoporous SiO2 shell, the as-obtained MFNPs can be utilized not only as a contrast agent for dual modal up-conversion luminescence (UCL)/magnetic resonance (MR) bio-imaging, but can also achieve an effective magnetically targeted antitumor chemotherapy both in vitro and in vivo. Furthermore, the UCL intensity of UCNPs and the magnetic properties of Fe3O4 in the MFNPs were carefully balanced. Silica coating and further PEG modifying can improve the hydrophilicity and biocompatibility of the as-synthesized MFNPs, which was confirmed by the in vitro/in vivo biocompatibility and in vivo long-time bio-distributions tests. Those results revealed that the UCNPs based magnetically targeted drug carrier system we synthesized has great promise in the future for multimodal bio-imaging and targeted cancer therapy. PMID:25521795

Liu, Bei; Li, Chunxia; Ma, Ping'an; Chen, Yinyin; Zhang, Yuanxin; Hou, Zhiyao; Huang, Shanshan; Lin, Jun

2015-01-22

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

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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; Masturi; Bijaksana, Satria; Khairurrijal; Abdullah, Mikrajuddin

2011-12-01

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Preparation of Fe3O4 magnetic nanoparticles coated with gallic acid for drug delivery  

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Full Text Available Dena Dorniani,1 Mohd Zobir Bin Hussein,1,2 Aminu Umar Kura,3 Sharida Fakurazi,3 Abdul Halim Shaari,4 Zalinah Ahmad51Chemistry Department, Faculty of Science, 2Advanced Materials and Nanotechnology Laboratory, Institute of Advanced Technology, 3Vaccines and Immunotherapeutics Laboratory, 4Physics Department, Faculty of Science, 5Chemical Pathology Unit, Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, MalaysiaBackground and methods: Magnetic iron oxide nanoparticles were prepared using a sonochemical method under atmospheric conditions at a Fe2+ to Fe3+ molar ratio of 1:2. The iron oxide nanoparticles were subsequently coated with chitosan and gallic acid to produce a core-shell structure.Results: X-ray diffraction demonstrated that the magnetic nanoparticles were pure Fe3O4 with a cubic inverse spinel structure. Transmission electron microscopy showed that the Fe3O4 nanoparticles were of spherical shape with a mean diameter of 11 nm, compared with 13 nm for the iron oxide-chitosan-gallic acid (FCG nanocarriers.Conclusion: The magnetic nanocarrier enhanced the thermal stability of the drug, gallic acid. Release of the active drug from the FCG nanocarrier was found to occur in a controlled manner. The gallic acid and FCG nanoparticles were not toxic in a normal human fibroblast (3T3 line, and anticancer activity was higher in HT29 than MCF7 cell lines.Keywords: magnetic nanoparticles, chitosan, superparamagnetic, controlled-release, gallic acid, drug delivery

Dorniani D

2012-11-01

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

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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

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

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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)

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

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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

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

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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

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Fabrication of docetaxel surfaced Fe3O4 magnetite nanoparticles and their cytotoxicity on 4?T1 breast cancer cells  

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Full Text Available Abstract 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??g pure docetaxel compound. Docetaxel showed aniproliferative effects against mentioned cell line. The higestest concentartion of docetaxel (80??g/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??g/ml can exhibit higher cytotoxic effect against this cancer cell line (90% cell death.

Yazdi MH

2012-08-01

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Fe3O4/carbon hybrid nanoparticle electrodes for high-capacity electrochemical capacitors.  

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Fe3O4/carbon hybrid nanoparticles (FeCHNPs) were fabricated using dual-nozzle electrospraying, vapor deposition polymerization (VDP), and carbonization. FeOOH nanoneedles decorated with polypyrrole (PPy) nanoparticles (FePNPs) were fabricated by electrospraying pristine PPy mixed with FeCl3 solution, followed by heating stirring reaction. A PPy coating was then formed on the FeOOH nanoneedles through a VDP process. FeCHNPs were produced through carbonization of PPy and FeOOH phase transitions. These hybrid carbon nanoparticles (NPs) were used to build electrodes of electrochemical capacitors. The specific capacitance of the FeCHNPs was 455?F?g(-1), which is larger than that of pristine PPy NPs (105?F?g(-1)) or other hybrid PPy NPs. Furthermore, the FeCHNP-based capacitors exhibited better cycle stability during charge-discharge cycling than other hybrid NP capacitors. This is because the carbon layer on the Fe3 O4 surface formed a protective coating, preventing damage to the electrode materials during the charge-discharge processes. This fabrication technique is an effective approach for forming stable carbon/metal oxide nanostructures for energy storage applications. PMID:24706636

Lee, Jun Seop; Shin, Dong Hoon; Jun, Jaemoon; Lee, Choonghyeon; Jang, Jyongsik

2014-06-01

 
 
 
 
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Interface composition between Fe3O4 nanoparticles and GaAs for spintronic applications  

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Recent interest in spintronic applications has necessitated the study of magnetic materials in contact with semiconductor substrates; importantly, the structure and composition of these interfaces can influence both device functionality and the magnetic properties. Nanoscale ferromagnet/semiconductor structures are of particular interest. In this study, the interface structure between a monolayer of ferromagnetic magnetite (Fe3O4) nanoparticles and a GaAs substrate was studied using cross-sectional transmission electron microscopy techniques. It was found that a continuous amorphous oxide interface layer separates the nanoparticles from the GaAs substrate, and that iron diffused into the interface layer forming a compositional gradient. Electron energy-loss near-edge fine structures of the O K absorption edge revealed that the amorphous oxide is composed of ?-Fe2O3 directly underneath the Fe3O4 nanoparticles, followed by a solid solution of Ga2O3 and FeO and mostly Ga2O3 when approaching the buckled oxide/substrate interface. Real-space density functional theory calculations of the dynamical form factor confirmed the experimental observations. The implication of the findings on the optimization of these structures for spin injection is discussed.

Hihath, Sahar; Kiehl, Richard A.; Benthem, Klaus van

2014-08-01

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Synthesis and characterization of photo-functional magnetic nanoparticles (Fe3O4@HP) for applications in photodynamic cancer therapy  

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Nowadays, photodynamic therapy (PDT) is a quite promising approach for killing various cancer cells. In this work, we report on photo-functional magnetic nanoparticles conjugated with hematoporphyrin (HP) (Fe3O4@HP) via a simple surface modification process. The microstructure and the magnetic properties of the Fe3O4 nanoparticles were investigated by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and vibrating sample magnetometry (VSM), and the biocompatibility and the photo-killing activity were evaluated using mammalian cells in vitro to confirm the potential of these particles for use as an agent for PDT application. We have demonstrated that the Fe3O4@HP nanoparticles show good biocompatibilities in fibroblast (L-929) and prostate cancer (PC-3) cells and have remarkable photodynamic anticancer activities. Especially, the photo-killing activities for 25, 50, and 100 ?g/ml of Fe3O4@HP were found to be above 86% (86.6, 99.2, and 99.4%, respectively) in PC-3 cells, demonstrating significantly high anticancer effects on prostate cancer cells, these effects depend on the concentration of the Fe3O4@HP nanoparticles. These results indicate that our Fe3O4@HP nanoparticles can be useful for PDT, although further studies to evaluate the cell-death mechanisms in vitro and in vivo will be needed to verify the potential for clinical PDT applications.

Choi, Kyong-Hoon; Nam, Ki Chang; Kim, Ho-Joong; Min, Jeeeun; Uhm, Han Sup; Choi, Eun Ha; Park, Bong Joo; Jung, Jin-Seung

2014-11-01

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One-pot solvothermal synthesis of Fe3O4–PEI composite and its further modification with Au nanoparticles  

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A one-step strategy for the facile synthesis of polyethyleneimine-functionalized Fe3O4 (Fe3O4-PEI) composite is presented in this study. We also investigated the effects of reaction time and NaAc on the composite sizes. The composite with good dispersion, wonderful crystallization, and excellent magnetism was obtained through one-pot solvothermal reaction. In the sequential presence of PEI and colloidal gold (Au) solution, plentiful Au nanoparticles with a diameter of 5 nm were assembled on the surface of Fe3O4–PEI to get Fe3O4–PEI–Au1–PEI–Au2 (Fe3O4/Au) composite. In-depth characterization of the composite formation process was performed using transmission electron microscopy, scanning electron microscope, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, and UV–Visible spectroscopy. The Fe3O4/Au composite was obtained with an average diameter of 150 nm, and the absorption peak was red-shifted to 580 nm. The synthesized Fe3O4/Au composite, the saturation magnetization of which was 40.4 emu/g, presented good magnetic property. Moreover, the composite could easily combine with up to 890 ?g antibodies per mg, and the antibodies still kept good immunocompetence after immobilization. These advantages suggest its These advantages suggest its great potential for applications in vitro, such as separation and immunoassay.

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

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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; Nan, Zhaodong

2011-12-01

125

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

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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

126

Alpha chymotrypsin coated clusters of Fe3O4 nanoparticles for biocatalysis in low water media  

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Full Text Available Abstract Background Enzymes in low water containing non aqueous media are useful for organic synthesis. For example, hydrolases in such media can be used for synthetic purposes. Initial work in this area was carried out with lyophilized powders of enzymes. These were found to have poor activity. Drying (removing bulk water by precipitation turned out to be a better approach. As enzymes in such media are heterogeneous catalysts, spreading these precipitates over a large surface gave even better results. In this context, nanoparticles with their better surface to volume ratio provide obvious advantage. Magnetic nanoparticles have an added advantage of easy separation after the reaction. Keeping this in view, alpha chymotrypsin solution in water was precipitated over a stirred population of Fe3O4 nanoparticles in n-propanol. This led to alpha chymotrypsin activity coated over clusters of Fe3O4 nanoparticles. These preparations were found to have quite high transesterification activity in low water containing n-octane. Results Precipitation of alpha chymotrypsin over a stirred suspension of Fe3O4 nanoparticles (3.6 nm diameter led to the formation of enzyme coated clusters of nanoparticles (ECCNs. These clusters were also magnetic and their hydrodynamic diameter ranged from 1.2- 2.6 microns (as measured by dynamic light scattering. Transmission electron microscopy (TEM, showed that these clusters had highly irregular shapes. Transesterification assay of various clusters in anhydrous n-octane led to optimization of concentration of nanoparticles in suspension during precipitation. Optimized design of enzyme coated magnetic clusters of nanoparticles (ECCN 3 showed the highest initial rate of 465 nmol min-1 mg-1protein which was about 9 times higher as compared to the simple precipitates with an initial rate of 52 nmol min-1 mg-1 protein. Circular Dichroism (CD(with a spinning cell accessory showed that secondary structure content of the alpha Chymotrypsin in ECCN 3 [15% ?-helix, 37% ?-sheet and 48% random coil] was identical to the simple precipitates of alpha chymotrypsin. Conclusion A strategy for obtaining a high activity preparation of alpha chymotrypsin for application in low water media is described. Such high activity biocatalysts are useful in organic synthesis.

Mukherjee Joyeeta

2012-11-01

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Linear birefringence and dichroism in citric acid coated Fe3O4 magnetic nanoparticles  

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To prepare highly dispersed water-based Fe3O4 magnetic nanoparticles (MNPs), we adopted the co-precipitation method and used citric acid (CA) as the surfactant. Via transmission electronic microscopy, dynamic light scattering, and X-ray diffractometry, we characterized the dispersibility and size of the products. Through two single-parameter experiments, including the pH value of suspension and the action of double centrifugations, the appropriate parameters' values were determined. Further, to produce CA coated MNPs with good magneto-optical properties as high retardance and low dichroism, the orthogonal design method was used to find the optimal parameters' values, including pH value of suspension after coating was 5, molar ratio of CA to Fe3O4 MNPs was 0.06, volume of CA was 40 ml, and coating temperature was 70 °C. Above all, the linear birefringence and dichroism of the best CA coated ferrofluid we produced were measured by a Stokes polarimeter as 23.6294° and 0.3411 under 64.5 mT, respectively. Thus, the biomedical applications could be performed hereafter.

Lin, Jing-Fung; Tsai, Chun-Chin; Lee, Meng-Zhe

2014-12-01

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Preparation of acid-base bifunctional core-shell structured Fe3O4@SiO2 nanoparticles and their cooperative catalytic activity  

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An acid-base bifunctionalized magnetic nanoparticles catalyst Fe3O4@SiO2-A/B was successfully synthesized by immobilization of both organic base and acid groups together over silica-coated magnetite nanoparticles. The catalyst has been characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS) measurements. The bifunctionalized magnetic nanoparticles act as an easily recovered, highly efficient catalyst for the Henry reaction of 4-nitrobenzaldehyde with nitromethane at mild reaction conditions, even exceeding any monofunctionalized catalyst or physical mixture of two monofunctionalized nanoparticles in the catalytic behavior. In addition, a probable mechanism has been proposed to explain the cooperative interactions from the presence of the immobilized base and acid groups in close proximity. Importantly, the catalyst can be simply recoverable from the reaction mixture by magnetic decantation and recycled without significant degradation in reactivity.

Long, Yu; Xie, Miao; Niu, Jianrui; Wang, Peng; Ma, Jiantai

2013-07-01

129

Preparation of acid–base bifunctional core–shell structured Fe3O4@SiO2 nanoparticles and their cooperative catalytic activity  

International Nuclear Information System (INIS)

An acid–base bifunctionalized magnetic nanoparticles catalyst Fe3O4@SiO2-A/B was successfully synthesized by immobilization of both organic base and acid groups together over silica-coated magnetite nanoparticles. The catalyst has been characterized by transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectra (XPS) measurements. The bifunctionalized magnetic nanoparticles act as an easily recovered, highly efficient catalyst for the Henry reaction of 4-nitrobenzaldehyde with nitromethane at mild reaction conditions, even exceeding any monofunctionalized catalyst or physical mixture of two monofunctionalized nanoparticles in the catalytic behavior. In addition, a probable mechanism has been proposed to explain the cooperative interactions from the presence of the immobilized base and acid groups in close proximity. Importantly, the catalyst can be simply recoverable from the reaction mixture by magnetic decantation and recycled without significant degradation in reactivity.

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

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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.

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Line Narrowing in Mössbauer Spectra of Superparamagnetic Fe3O4 Nanoparticles  

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Nanoparticles of magnetic crystals below a critical size are single domain and exhibit superparamagnetism. If there are N atoms or molecules with magnetic moment ? in each particle, the magnetic moment of the particle is N?. At high temperatures the thermal fluctuations of the magnetic moments give an ensemble average moment of zero and the Mössbauer spectrum is a single line. As the temperature, T, is lowered the fluctuations slow down and the sample acquires a magnetization and the Mossbauer line broadens and eventually shows magnetic hyperfine splitting. We have observed 57Fe line broadening in nanoparticles of ferrimagnetic Fe3O4 with diameters of 5.3 and 10.6 nm. The results have been analyzed using the motional narrowing equation familiar in nuclear magnetic resonance to determine the superparamagnetic fluctuation time and magnetic anisotropy.

Hah, H.-Y.; Gray, S.; Johnson, C. E.; Johnson, J. A.; Kolesnichenko, V.; Kucheryavy, P.; Goloverda, G.

2014-11-01

132

Mechanism and controlled growth of shape and size variant core/shell FeO/Fe3O4 nanoparticles.  

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We report a novel synthesis approach for the growth of core/shell FeO/Fe3O4 nanoparticles with controlled shape and size. FeO particles were partially oxidized to form core/shell FeO/Fe3O4 structures, as evidenced from transmission electron microscopy, X-ray diffraction, and magnetometry analysis. We find that the molar ratios and concentrations of surfactants are the key parameters in controlling the particle size. The particles can grow in either isotropic or anisotropic shapes, depending upon a chemical reaction scheme that is controlled kinetically or thermodynamically. The competitive growth rates of {111} and {100} facets can be used to tune the final shape of nanoparticles to spherical, cubic, octahedral, octopod, and cuboctahedral geometries. FeO particles can also be oxidized chemically or thermally to form Fe3O4 nanoparticles. By following the same synthesis technique, it is possible to synthesize rods and triangles of Fe3O4 by introducing twinnings and defects into the crystal structure of the seed. The thermally activated first-order Verwey transition at ~120 K has been observed in all the synthesized FeO/Fe3O4 nanoparticles, indicating its independence from the particle shape. These core/shell nanoparticles exhibit a strong shift in field-cooled hysteresis loops accompanied by an increase in coercivity (the so-called exchange bias effect), but the low field-switching behavior appears to vary with the particle shape. PMID:23857290

Khurshid, Hafsa; Li, Wanfeng; Chandra, Sayan; Phan, Manh-Huong; Hadjipanayis, George C; Mukherjee, Pritish; Srikanth, Hariharan

2013-09-01

133

Mechanism and controlled growth of shape and size variant core/shell FeO/Fe3O4 nanoparticles  

Science.gov (United States)

We report a novel synthesis approach for the growth of core/shell FeO/Fe3O4 nanoparticles with controlled shape and size. FeO particles were partially oxidized to form core/shell FeO/Fe3O4 structures, as evidenced from transmission electron microscopy, X-ray diffraction, and magnetometry analysis. We find that the molar ratios and concentrations of surfactants are the key parameters in controlling the particle size. The particles can grow in either isotropic or anisotropic shapes, depending upon a chemical reaction scheme that is controlled kinetically or thermodynamically. The competitive growth rates of {111} and {100} facets can be used to tune the final shape of nanoparticles to spherical, cubic, octahedral, octopod, and cuboctahedral geometries. FeO particles can also be oxidized chemically or thermally to form Fe3O4 nanoparticles. By following the same synthesis technique, it is possible to synthesize rods and triangles of Fe3O4 by introducing twinnings and defects into the crystal structure of the seed. The thermally activated first-order Verwey transition at ~120 K has been observed in all the synthesized FeO/Fe3O4 nanoparticles, indicating its independence from the particle shape. These core/shell nanoparticles exhibit a strong shift in field-cooled hysteresis loops accompanied by an increase in coercivity (the so-called exchange bias effect), but the low field-switching behavior appears to vary with the particle shape.

Khurshid, Hafsa; Li, Wanfeng; Chandra, Sayan; Phan, Manh-Huong; Hadjipanayis, George C.; Mukherjee, Pritish; Srikanth, Hariharan

2013-08-01

134

Functionalization of PEGylated Fe3O4 magnetic nanoparticles with tetraphosphonate cavitand for biomedical application  

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In this contribution, Fe3O4 magnetic nanoparticles (MNPs) have been functionalized with a tetraphosphonate cavitand receptor (Tiiii), capable of complexing N-monomethylated species with high selectivity, and polyethylene glycol (PEG) via click-chemistry. The grafting process is based on MNP pre-functionalization with a bifunctional phosphonic linker, 10-undecynylphosphonic acid, anchored on an iron surface through the phosphonic group. The Tiiii cavitand and the PEG modified with azide moieties have then been bonded to the resulting alkyne-functionalized MNPs through a ``click'' reaction. Each reaction step has been monitored by using X-ray photoelectron and FTIR spectroscopies. PEG and Tiiii functionalized MNPs have been able to load N-methyl ammonium salts such as the antitumor drug procarbazine hydrochloride and the neurotransmitter epinephrine hydrochloride and release them as free bases. In addition, the introduction of PEG moieties promoted biocompatibility of functionalized MNPs, thus allowing their use in biological environments.

Tudisco, C.; Bertani, F.; Cambria, M. T.; Sinatra, F.; Fantechi, E.; Innocenti, C.; Sangregorio, C.; Dalcanale, E.; Condorelli, G. G.

2013-11-01

135

Polyethyleneimine-modified superparamagnetic Fe3O4 nanoparticles: An efficient, reusable and water tolerance nanocatalyst  

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A novel magnetically separable catalyst was prepared based on surface modification of Fe3O4 magnetic nanoparticle (MNPs) with polyethyleneimine (PEI) via covalent bonding. [3-(2,3-Epoxypropoxy)propyl]trimethoxysilane (EPO) was used as cross linker to bond PEI on the surface of MNPs with permanent stability in contrast to PEI coating via electrostatic interactions. The synthesized catalyst was characterized by Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The catalyst show high efficiency for one-pot synthesis of 2-amino-3-cyano-4H-pyran derivatives via multi-component reaction (MCR). This procedure offers the advantages of green reaction media, high yield, short reaction time, easy purification of the products and simple recovery and reuse of the catalyst by simple magnetic decantation without significant loss of catalytic activity.

Khoobi, Mehdi; Delshad, Tayebeh Modiri; Vosooghi, Mohsen; Alipour, Masoumeh; Hamadi, Hosein; Alipour, Eskandar; Hamedani, Majid Pirali; Sadat ebrahimi, Seyed Esmaeil; Safaei, Zahra; Foroumadi, Alireza; Shafiee, Abbas

2015-02-01

136

Synthesis of Fe3O4 nanoparticles at 100 deg. C and its magnetic characterization  

International Nuclear Information System (INIS)

Superparamagnetic iron oxide nanoparticles were synthesized by a novel, simple and cost-effective gel-to-crystalline method by alkalizing ferrous chloride with ammonium hydroxide at 80-100 deg. C under refluxing conditions. Average crystallite size is determined as 11 nm from XRD and 11.4 nm from TEM: magnetic domain size is 9.7 nm. The saturation magnetization is 390 emu/cm3 at 300 K, and TB is 134 K. The reduction of magnetic particle size and Ms is attributed to the presence of non-magnetic (dead) surface layer, compositional variations, superparamagnetic relaxation and spin canting because of the ultrafine nature of the material. The maximization in magnetization near the blocking temperature, TB, is attributed to a large degree of inversion of the Fe3O4 particles. Results also indicated the existence of interparticle interactions in the thermomagnetic characteristics of spinels at lower field strengths

137

Controlled Synthesis of Fe3O4/Ag Core-Shell Composite Nanoparticles with High Electrical Conductivity  

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The presented method provides an easy processing route to synthesize Fe3O4/Ag core-shell composite nanoparticles. Their structures were characterized by x-ray diffraction and transmission electron microscopy. The average size of the Fe3O4 core and Ag shell was about 32.0 nm and 5.0 nm (or 28.0 nm), respectively. Furthermore, magnetic measurements showed that the composite nanoparticles exhibited typical superparamagnetic behavior, specific saturation magnetization of ca. 24.0 emu/g, and intrinsic coercivity of 106.0 Oe. At the same time, high conductivity (64.7 S/cm) of the composite nanoparticles was also observed. This method provides an opportunity to synthesize other core-shell (Fe3O4) nanoparticles in a single step.

Sun, Youyi; Tian, Ye; He, Minghong; Zhao, Qing; Chen, Chuang; Hu, Changsheng; Liu, Yaqing

2012-03-01

138

Synthesis of PVP-coated ultra-small Fe3O4 nanoparticles as a MRI contrast agent.  

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Ultra-small Fe(3)O(4) nanoparticles were prepared by using the coprecipitation method, in which the polyvinylpyrrolidone (PVP) serves as a stabilizer. The nanoparticles were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), infra spectrum (IR), X-ray photoelectron spectroscopy (XPS) and in vivo magnetic resonance imaging (MRI) test. The results showed that the particles' size was determined by the dripping rate and that PVP molecules played the role of preventing the aggregation and restricting the size of Fe(3)O(4) nanoparticles. The Fe(3)O(4) nanoparticles with diameter from 6.5 to 1.9 nm obviously exhibited negative contrast enhancement and concentrated at the target area guided by a permanent magnet. PMID:20140698

Zhang, Ying; Liu, Jing-Ying; Ma, Song; Zhang, Ya-Jing; Zhao, Xiang; Zhang, Xiang-Dong; Zhang, Zhi-Dong

2010-04-01

139

Functionalized Fe3 O4 @Silica Core-Shell Nanoparticles as Microalgae Harvester and Catalyst for Biodiesel Production.  

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Core-shell Fe3 O4 @silica magnetic nanoparticles functionalized with a strong base, triazabicyclodecene (TBD), were successfully synthesized for harvesting microalgae and for one-pot microalgae-to-fatty acid methyl ester (FAME, or so-called biodiesel) conversion. Three types of algae oil sources (i.e., dried algae, algae oil, and algae concentrate) were used and the reaction conditions were optimized to achieve the maximum biodiesel yield. The results obtained in this study show that our TBD-functionalized Fe3 O4 @silica nanoparticles could effectively convert algae oil to biodiesel with a maximum yield of 97.1?%. Additionally, TBD-Fe3 O4 @silica nanoparticles act as an efficient algae harvester because of their adsorption and magnetic properties. The method presented in this study demonstrates the wide scope for the use of covalently functionalized core-shell nanoparticles for the production of liquid transportation fuels from algal biomass. PMID:25477296

Chiang, Ya-Dong; Dutta, Saikat; Chen, Ching-Tien; Huang, Yu-Tzu; Lin, Kuen-Song; Wu, Jeffrey C S; Suzuki, Norihiro; Yamauchi, Yusuke; Wu, Kevin C-W

2014-12-01

140

Characterization of aqueous dispersions of Fe(3)O(4) nanoparticles and their biomedical applications.  

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A newly developed non-polymer coated Fe(3)O(4) nanoparticles showing well-dispersion were synthesized using Fe(II) and Fe(III) salt chemical coprecipitation with tetramethylammonium hydroxide (N(CH(3))(4)OH) in an aqueous solution. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), X-ray photoelectron spectrometer (XPS) and superconducting quantum interference measurement device (SQUID) measurements were employed to investigate the iron oxide properties. The resulting iron oxide particles were manipulated to be as small as 9 nm diameter in size. Based on FT-IR and X-ray photoelectron spectrometer results, it is suggested that the surfaces of the magnetite (Fe(3)O(4)) particles are covered with hydroxide (-OH) groups incorporated with (CH(3))(4)N(+) through electrostatic interaction. The in vitro cytotoxicity test revealed that the magnetite particles exhibited excellent biocompatibility, suggesting that they may be further explored for biomedical applications. NMR measurements revealed significantly reduced water proton relaxation times T1 and T2. The MR images of the nanoparticles in water, serum, and whole blood were investigated using a 1.5 T clinical MR imager. Significant reduction of the background medium signal was achieved in the T2-weighted and the T2*-weighted sequence especially in the serum and whole blood. Combining the advantage of MRI signal contrast, the non-polymer-coated surface chemistry for distinct bioconjugation and the homogenous nanometer size for better controlled biodistribution, these preliminary experiments demonstrated the potential of the as-synthesized magnetite material in functional molecular imaging for biomedical research and clinical diagnosis. PMID:15350777

Cheng, Fong-Yu; Su, Chia-Hao; Yang, Yu-Sheng; Yeh, Chen-Sheng; Tsai, Chiau-Yuang; Wu, Chao-Liang; Wu, Ming-Ting; Shieh, Dar-Bin

2005-03-01

 
 
 
 
141

Characterisation of Co@Fe3O4 core@shell nanoparticles using advanced electron microscopy  

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Cobalt nanoparticles were synthesised via the thermal decomposition of Co2(CO)8 and were coated in iron oxide using Fe(CO)5. While previous work focused on the subsequent thermal alloying of these nanoparticles, this study fully elucidates their composition and core@shell structure. State-of-the-art electron microscopy and statistical data processing enabled chemical mapping of individual particles through the acquisition of energy-filtered transmission electron microscopy (EFTEM) images and detailed electron energy loss spectroscopy (EELS) analysis. Multivariate statistical analysis (MSA) has been used to greatly improve the quality of elemental mapping data from core@shell nanoparticles. Results from a combination of spatially resolved microanalysis reveal the shell as Fe3O4 and show that the core is composed of oxidatively stable metallic Co. For the first time, a region of lower atom density between the particle core and shell has been observed and identified as a trapped carbon residue attributable to the organic capping agents present in the initial Co nanoparticle synthesis.Cobalt nanoparticles were synthesised via the thermal decomposition of Co2(CO)8 and were coated in iron oxide using Fe(CO)5. While previous work focused on the subsequent thermal alloying of these nanoparticles, this study fully elucidates their composition and core@shell structure. State-of-the-art electron microscopy and statistical data processing enabled chemical mapping of individual particles through the acquisition of energy-filtered transmission electron microscopy (EFTEM) images and detailed electron energy loss spectroscopy (EELS) analysis. Multivariate statistical analysis (MSA) has been used to greatly improve the quality of elemental mapping data from core@shell nanoparticles. Results from a combination of spatially resolved microanalysis reveal the shell as Fe3O4 and show that the core is composed of oxidatively stable metallic Co. For the first time, a region of lower atom density between the particle core and shell has been observed and identified as a trapped carbon residue attributable to the organic capping agents present in the initial Co nanoparticle synthesis. Electronic supplementary information (ESI) available: Further HRTEM images, EDS, EELS and EDS line scans, EFTEM and eigenvectors for MSA analysis. See DOI: 10.1039/c3nr33789h

Knappett, Benjamin R.; Abdulkin, Pavel; Ringe, Emilie; Jefferson, David A.; Lozano-Perez, Sergio; Rojas, T. Cristina; Fernández, Asunción; Wheatley, Andrew E. H.

2013-06-01

142

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

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Water-soluble l-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 binding l-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 the l-arginine-capped magnetite nanoparticles. The as-prepared conjugates could be used in immunomagnetic assay.

Lai, Yongchao; Yin, Weiwei; Liu, Jinting; Xi, Rimo; Zhan, Jinhua

2010-02-01

143

Stability and magnetically induced heating behavior of lipid-coated Fe3O4 nanoparticles  

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Magnetic nanoparticles that are currently explored for various biomedical applications exhibit a high propensity to minimize total surface energy through aggregation. This study introduces a unique, thermoresponsive nanocomposite design demonstrating substantial colloidal stability of superparamagnetic Fe3O4 nanoparticles (SPIONs) due to a surface-immobilized lipid layer. Lipid coating was accomplished in different buffer systems, pH 7.4, using an equimolar mixture of 1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DPPC) and l-?-dipalmitoylphosphatidyl glycerol (DPPG). Particle size and zeta potential were measured by dynamic laser light scattering. Heating behavior within an alternating magnetic field was compared between the commercial MFG-1000 magnetic field generator at 7 mT (1 MHz) and an experimental, laboratory-made magnetic hyperthermia system at 16.6 mT (13.7 MHz). The results revealed that product quality of lipid-coated SPIONs was significantly dependent on the colloidal stability of uncoated SPIONs during the coating process. Greatest stability was achieved at 0.02 mg/mL in citrate buffer (mean diameter = 80.0 ± 1.7 nm; zeta potential = -47.1 ± 2.6 mV). Surface immobilization of an equimolar DPPC/DPPG layer effectively reduced the impact of buffer components on particle aggregation. Most stable suspensions of lipid-coated nanoparticles were obtained at 0.02 mg/mL in citrate buffer (mean diameter = 179.3 ± 13.9 nm; zeta potential = -19.1 ± 2.3 mV). The configuration of the magnetic field generator significantly affected the heating properties of fabricated SPIONs. Heating rates of uncoated nanoparticles were substantially dependent on buffer composition but less influenced by particle concentration. In contrast, thermal behavior of lipid-coated nanoparticles within an alternating magnetic field was less influenced by suspension vehicle but dramatically more sensitive to particle concentration. These results underline the advantages of lipid-coated SPIONs on colloidal stability without compromising magnetically induced hyperthermia properties. Since phospholipids are biocompatible, these unique lipid-coated Fe3O4 nanoparticles offer exciting opportunities as thermoresponsive drug delivery carriers for targeted, stimulus-induced therapeutic interventions.

Allam, Ayat A.; Sadat, Md Ehsan; Potter, Sarah J.; Mast, David B.; Mohamed, Dina F.; Habib, Fawzia S.; Pauletti, Giovanni M.

2013-10-01

144

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 trichloroaceen 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.

145

The effect of ligands on FePt-Fe3O4 core-shell magnetic nanoparticles.  

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FePt-Fe3O4 core-shell nanoparticles functionalized with 3,4-dihydroxyphenylacetic acid (DOPAC) and dimercaptosuccinic acid (DMSA) ligands were synthesized and characterized. We found that the DOPAC ligand enhances the magnetic properties of the FePt-Fe3O4 particles, in comparison with the DMSA ligand, which induces the oxidation of the shell layer that causes a significant reduction of the saturation magnetization. The synthesized magnetic nanoparticles were evaluated for applications in magnetic hyperthermia and magnetic resonance imaging contrast enhancement. PMID:24745278

Kim, Dong-Hyun; Tamada, Yoshinori; Ono, Teruo; Bader, Samuel D; Rozhkova, Elena A; Novosad, Valentyn

2014-03-01

146

Tailoring biocompatible Fe3O4 nanoparticles for applications to magnetic hyperthermia  

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Magnetite based nanoparticles functionalized with different ligands have been obtained by optimization of two synthetic methods. Gold surrounded Fe3O4 nanoparticles capped with oleic acid and oleylamine were achieved by thermal decomposition of metallo-organic precursors. By this way nanoparticles with perfectly defined size within 3.5 nm to 7 nm in diameter and organic content from 16.1% to 40.9 % were obtained. Precipitation of iron(II) chloride in basic solution yield magnetite nanoparticles between 20 and 40 nm with contents of organic ligands of 3 - 12 %. The samples have been characterized by X-ray diffraction, transmission electron microscopy and thermogravimetric measurements. A complete magnetic study has been performed by means of a SQUID magnetometer and electron magnetic resonance (EMR), showing the influence of capping covering on the superparamagnetic behaviour. The citotoxicity and interaction with HeLa cells was evaluated for some of the preparations. Finally, the specific absorption rate (SAR) was calculated to compare the efficiency of heating each sample for the various applied magnetic fields.

Insausti, Maite; Salado, Javier; Castellanos, Idoia; Lezama, Luis; Gil de Muro, Izaskun; de la Fuente, Jesús M.; Garayo, Eneko; Plazaola, Fernando; Rojo, Teófilo

2012-03-01

147

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.

148

Investigation of magnetic properties of Fe3O4 nanoparticles using temperature dependent magnetic hyperthermia in ferrofluids  

International Nuclear Information System (INIS)

Rate of heat generated by magnetic nanoparticles in a ferrofluid is affected by their magnetic properties, temperature, and viscosity of the carrier liquid. We have investigated temperature dependent magnetic hyperthermia in ferrofluids, consisting of dextran coated superparamagnetic Fe3O4 nanoparticles, subjected to external magnetic fields of various frequencies (188–375 kHz) and amplitudes (140–235 Oe). Transmission electron microscopy measurements show that the nanoparticles are polydispersed with a mean diameter of 13.8?±?3.1?nm. The fitting of experimental dc magnetization data to a standard Langevin function incorporating particle size distribution yields a mean diameter of 10.6?±?1.2?nm, and a reduced saturation magnetization (?65?emu/g) compared to the bulk value of Fe3O4 (?95?emu/g). This is due to the presence of a finite surface layer (?1?nm thickness) of non-aligned spins surrounding the ferromagnetically aligned Fe3O4 core. We found the specific absorption rate, measured as power absorbed per gram of iron oxide nanoparticles, decreases monotonically with increasing temperature for all values of magnetic field and frequency. Using the size distribution of magnetic nanoparticles estimated from the magnetization measurements, we have fitted the specific absorption rate versus temperature data using a linear response theory and relaxation dissipation mechanisms to determine the value of magnetic anisotropy constant (28?±?2?kJ/m3) of Fe3O4 nanoparticles.

149

Investigation of magnetic properties of Fe3O4 nanoparticles using temperature dependent magnetic hyperthermia in ferrofluids  

Science.gov (United States)

Rate of heat generated by magnetic nanoparticles in a ferrofluid is affected by their magnetic properties, temperature, and viscosity of the carrier liquid. We have investigated temperature dependent magnetic hyperthermia in ferrofluids, consisting of dextran coated superparamagnetic Fe3O4 nanoparticles, subjected to external magnetic fields of various frequencies (188-375 kHz) and amplitudes (140-235 Oe). Transmission electron microscopy measurements show that the nanoparticles are polydispersed with a mean diameter of 13.8 ± 3.1 nm. The fitting of experimental dc magnetization data to a standard Langevin function incorporating particle size distribution yields a mean diameter of 10.6 ± 1.2 nm, and a reduced saturation magnetization (˜65 emu/g) compared to the bulk value of Fe3O4 (˜95 emu/g). This is due to the presence of a finite surface layer (˜1 nm thickness) of non-aligned spins surrounding the ferromagnetically aligned Fe3O4 core. We found the specific absorption rate, measured as power absorbed per gram of iron oxide nanoparticles, decreases monotonically with increasing temperature for all values of magnetic field and frequency. Using the size distribution of magnetic nanoparticles estimated from the magnetization measurements, we have fitted the specific absorption rate versus temperature data using a linear response theory and relaxation dissipation mechanisms to determine the value of magnetic anisotropy constant (28 ± 2 kJ/m3) of Fe3O4 nanoparticles.

Nemala, H.; Thakur, J. S.; Naik, V. M.; Vaishnava, P. P.; Lawes, G.; Naik, R.

2014-07-01

150

Polyaniline shell cross-linked Fe3O4 magnetic nanoparticles for heat activated killing of cancer cells.  

Science.gov (United States)

Superparamagnetic Fe3O4 nanoparticles are appealing materials for heat activated killing of cancer cells. Here, we report a novel method to enhance the heat activated killing of cancer cells under an AC magnetic field (AMF) by introducing a polyaniline impregnated shell onto the surface of Fe3O4 nanoparticles. These polyaniline shell cross-linked magnetic nanoparticles (PSMN) were prepared by in situ polymerization of aniline hydrochloride on the surface of carboxyl PEGylated Fe3O4 nanoparticles. XRD and TEM analyses revealed the formation of single phase inverse spinel Fe3O4 nanoparticles of a size of about 10 nm. The successful growth of the polyaniline shell on the surface of carboxyl PEGylated magnetic nanoparticles (CPMN) is evident from FTIR spectra, DLS, TGA, zeta-potential and magnetic measurements. Both CPMN and PSMN show good colloidal stability, superparamagnetic behavior at room temperature and excellent heating efficacy under AMF. It has been observed that the heating efficacy of PSMN under AMF was slightly reduced as compared to that of CPMN. The enhanced toxicity of PSMN to cancer cells under AMF suggests their strong potential for magnetic hyperthermia. Furthermore, PSMN shows high loading affinity for an anticancer drug (doxorubicin), its sustained release and substantial internalization in tumor cells. PMID:24948377

Rana, Suman; Jadhav, Neena V; Barick, K C; Pandey, B N; Hassan, P A

2014-08-28

151

Highly cross-linked and biocompatible polyphosphazene-coated superparamagnetic Fe3O4 nanoparticles for magnetic resonance imaging.  

Science.gov (United States)

Highly cross-linked and biocompatible poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) were used to directly coat hydrophilic superparamagnetic Fe3O4 nanoparticles by a facile but effective one-pot polycondensation. The obtained core-shell Fe3O4@PZS nanohybrids were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and X-ray diffraction spectra. Interesting, the size and T2 relaxivity of Fe3O4@PZS increased with increasing the mass ratio of Fe3O4 to PZS. All these nanohybrids could be internalized by HeLa cells but show negligible cytotoxicity. The PZS layer slowly degraded into less dangerous forms such as 4,4'-sulfonyldiphenol, phosphate and ammonia at neutral or acid atmosphere. Considering their excellent water dispersibility, colloidal and chemical stability, magnetic manipulation, and magnetic resonance imaging (MRI) properties, Fe3O4@PZS nanohybrids have great potential in MRI diagnosis of cancer. PMID:23795597

Hu, Ying; Meng, Lingjie; Niu, Lvye; Lu, Qinghua

2013-07-23

152

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

153

Synthesis of M–Nd doped Fe3O4 nanoparticles (M = Co, Ce, Cr, Ni with tunable magnetic properties  

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Full Text Available Magnetic nanoparticles were prepared by the aqueous co-precipitation method. The magnetic nanoparticles obtained were characterized systematically through the use of an X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDS, scanning electron microscope (SEM, transmission electron microscope (TEM, Fourier transform infrared spectroscopy (FT-IR and a vibrating sampling magnetometer (VSM. The results revealed that the magnetic nanoparticles were spherical shaped with inverse spinel structure. The size of Fe3O4 and Nd-Co doped Fe3O4 magnetic nanoparticles were approximately 15 nm. Magnetic measurement revealed that the nanoparticles were super paramagnetic at room temperature. It was found that the magnetic response of the Fe3O4 increased when it was doped with Nd3+ and Co2+. However, the magnetic response of the Fe3O4 decreased when it was doped with Nd3+ or Ce3+ or Cr3+or Ni2+.DOI: http://dx.doi.org/10.4314/bcse.v27i1.5

P. Alimard

2013-04-01

154

Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nano tubes and Their Use as Magnetically Recyclable Catalysts  

International Nuclear Information System (INIS)

We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nano tubes (CNTs). The superparamagnetic Fe3O4 nanoparticles with average size of 45 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanoparticles and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanoparticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

155

Synthesis and characterization of polyethylene glycol (PEG) coated Fe3O4 nanoparticles by chemical co-precipitation method for biomedical applications  

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Polyethylene glycol (PEG) coated Fe3O4 nanoparticles were synthesized by chemical co-precipitation method. With polyethylene glycol (PEG) as a stabilizer and dispersant. The X-ray diffraction and selected area electron diffraction (SAED) results show that the cubic inverse spinel structure of pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and field emission transmission electron microscopy (FE-TEM) results exhibited that the resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FT-IR) results suggested that PEG indicated with Fe3O4 via its carbonyl groups. Results of vibrating sample magnetometer (VSM) indicated that the prepared Fe3O4 nanoparticles exhibit superparamagnetic behavior and high saturation magnetization at room temperature. Such Fe3O4 nanoparticles with favorable size and tunable magnetic properties are promising biomedical applications.

Anbarasu, M.; Anandan, M.; Chinnasamy, E.; Gopinath, V.; Balamurugan, K.

2015-01-01

156

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

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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 supelectron 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.

157

Magnetic properties of Cr doped Fe3O4 porous nanoparticles prepared through a co-precipitation method using surfactant  

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Magnetic Cr3+xFe3+2 ? xFe2+O4 (0 ?? x ?? 0.1) porous nanoparticles were prepared by the aqueous co-precipitation method. The resulting magnetic nanoparticles were characterized by using an x-ray diffraction (XRD), field enhanced scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sampling magnetometer (VSM). The nitrogen gas adsorption/desorption isotherm showed a microporous structure of the obtained magnetic materials. A rod and round shape of Fe3O4 was observed as using polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) surfactant, respectively. The Fe3O4 nanoparticles exhibited superparamagnetic properties with easy separation and re-dispersion in solution by using an external magnet. More remarkably, the saturation magnetization (Ms) was enhanced up to 1.2 times for doping Cr3+ into the Fe3O4 lattice. The effect of surfactants and Cr3+ doping concentrations on size and the magnetic properties of Fe3O4 nanoparticles are studied.

Duy Nguyen, Hoang; Dzung Nguyen, Trung; Hai Nguyen, Dai; Nguyen, Phuong Tung

2014-09-01

158

Photothermal effects and toxicity of Fe3O4 nanoparticles via near infrared laser irradiation for cancer therapy.  

Science.gov (United States)

The photothermal effect of magnetite (Fe3O4) nanoparticles was characterized by photonic absorption in the near-infrared (NIR) region. Upon laser irradiation at 785nm, the Fe3O4 nanoparticles generate localized hyperthermia in tumorous lesions, which is an effective strategy for cancer therapy; however, uncoated magnetite possesses an innate toxicity which can lead to drawbacks in the clinical setting. To reduce innate toxicity, a poly(acrylic acid) (PAA) coating on the nanoparticles was investigated in order to determine the alterations to stability and the degree of toxicity in an attempt to create a higher utility vector. It was found that the PAA coating significantly reduced the innate toxicity of the uncoated magnetite. Furthermore, the efficacy of PAA-coated magnetite nanoparticles (PAA-Fe3O4) was investigated for treating MDA-MB-231 (human mammary gland adenocarcinoma) cultures in viable concentration ranges (0.1-0.5mg/ml). An appropriate PAA-Fe3O4 concentration range was then established for inducing significant cell death by hyperthermic ablation, but not through innate toxicity. PMID:25491964

Dunn, Andrew W; Ehsan, Sadat M; Mast, David; Pauletti, Giovanni M; Xu, Hong; Zhang, Jiaming; Ewing, Rodney C; Shi, Donglu

2015-01-01

159

Biocompatible PEGylated Fe3O4 Nanoparticles as Photothermal Agents for Near-Infrared Light Modulated Cancer Therapy  

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Full Text Available In accordance with the World Cancer Report, cancer has become the leading cause of mortality worldwide, and various therapeutic strategies have been developed at the same time. In the present study, biocompatible magnetic nanoparticles were designed and synthesized as high-performance photothermal agents for near-infrared light mediated cancer therapy in vitro. Via a facile one-pot solvothermal method, well-defined PEGylated magnetic nanoparticles (PEG–Fe3O4 were prepared with cheap inhesion as a first step. Due to the successful coating of PEG molecules on the surface of PEG–Fe3O4, these nanoparticles exhibited excellent dispersibility and dissolvability in physiological condition. Cytotoxicity based on MTT assays indicated these nanoparticles revealed high biocompatibility and low toxicity towards both Hela cells and C6 cells. After near-infrared (NIR laser irradiation, the viabilities of C6 cells were effectively suppressed when incubated with the NIR laser activated PEG–Fe3O4. In addition, detailed photothermal anti-cancer efficacy was evaluated via visual microscope images, demonstrating that our PEG–Fe3O4 were promising for photothermal therapy of cancer cells.

Gang Yuan

2014-10-01

160

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

 
 
 
 
161

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

162

Hybrid composites made of multiwalled carbon nanotubes functionalized with Fe3O4 nanoparticles for tissue engineering applications  

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A straightforward technique for functionalization of multiwalled carbon nanotubes (MWCNTs) with magnetite (Fe3O4) nanoparticles was developed. Iron oxide nanoparticles were deposited on MWCNT surfaces by a deposition–precipitation method using Fe3+/Fe2+ salts precursors in basic solution. The characterizations by HRTEM, XRD, SEM/EDX, AAS and TPR analyses confirmed the successful formation of magnetic iron oxide nanoparticles on the MWCNT surface. Fe3O4/MWCNT hybrid composites were analysed in vitro by incubation with mesenchymal stem cells for 1, 3 and 7 days, either in the presence or absence of a static magnetic field. Analysis of cell proliferation was performed by the MTT assay, quantification of cellular stress was performed by the Lactate Dehydrogenase assay and analysis of cell morphology was performed by actin immunofluorescence and scanning electron microscopy. Results demonstrate that the introduction of magnetite into the MWCNT structure increases biocompatibility of oxidized MWCNTs. In addition, the presence of a static magnetic field further increases Fe3O4/MWCNT influence on cell behaviour. These results demonstrate this novel Fe3O4/MWCNT hybrid composite has good potential for tissue engineering applications. (paper)

163

N,N,N',N'-tetraoctyl diglycolamide coated Fe3O4 nanoparticles for americium preconcentration and determination with ?-spectrometry  

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N,N,N',N'-tetraoctyl diglycolamide (TODGA) was coated on Fe3O4 nanoparticles under different chemical conditions. TODGA coated on magnetic nanoparticles Fe3O4 captured representative actinide 241Am at 3-4 M HNO3 with a very high efficiency. However, it has been observed that HNO3 induced preorganization plays an important role in sorption of Am(III) ions even in its self-assembled monolayer on magnetic nanoparticles. As Am(III) sorption in TODGA coated Fe3O4 found to be quantitative (90%), this material was used for preconcentration of 241Am from aqueous sample and subjecting it for direct quantification with ?-spectrometry. A linear variation of ?-activity of 241Am sorbed in TODGA coated Fe3O4 with amount of 241Am spiked in equilibrating solution indicated potential application of this method for monitoring ultra-trace concentration of 241Am in large volume of aqueous samples using magnetically assisted separation. (author)

164

Multifunctional Fe3O4@C@Ag hybrid nanoparticles: Aqueous solution preparation, characterization and photocatalytic activity  

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Highlights: ? Ag-loaded Fe3O4@C magnetic-optical bifunctional materials have been investigated. ? The magnetism was studied at the room temperature. ? The photocatalytic activity was evaluated under visible light irradiation. ? Ag-loaded Fe3O4@C nanocomposites show superior magnetism and photocatalytic activity. ? A simple synthetic process was discussed. - Abstract: The paper describes a kind of multifunctional Fe3O4@C@Ag hybrid nanoparticles, which can be successfully synthesized using a simple route based on directly adsorption and spontaneous reduction of silver ions onto the surface shell of carbon-coated magnetic nanoparticles. The as-prepared samples have been characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectrum, vibrating sample magnetometer (VSM) and UV–vis spectrum (UV–vis). The Ag nanocrystals loaded on the surface shell of carbon-coated magnetic nanoparticles are nearly spherical with an average diameter of 10 nm. And the carbonaceous polysaccharides shell obtained using an glucose hydrothermal reaction act as a role of a bridge between magnetic Fe3O4 core and noble metallic Ag nanocrystals. The as-prepared samples can be used as an effective catalyst for the photodegradation of organic dyes (neutral red) under the exposure of visible light. Results show that the as-prepared samples have a degradation rate of 93.7% for dyes within 30 min, which indicates their high-efficiency and rapid photocatalytic activity

165

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

166

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

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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 range...

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

2013-01-01

167

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

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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 ferri...

Rosfarizan Mohamad; Mansor Bin Ahmad; Mahnaz Mahdavi; Farideh Namvar

2013-01-01

168

Preparation, structure, and magnetic properties of polystyrene coated by Fe3O4 nanoparticles.  

Science.gov (United States)

A novel method of fabricating core-shell structure particles, comprising nearly monodisperse polystyrene (PS) spheres as cores and Fe3O4 as shells, is submitted. In this research, the magnetite (Fe3O4) shell was prepared by seeded growth from the reaction of FeCl2 with diethylene glycol (DEG) in aqueous solutions. The thickness of the shell were controlled in the range of 0-60 nm by using slow injection. The composition and the structure of the shell were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TG), and vibrating-sample magnetometry (VSM). It is found that there are some differences between the magnetic composite spheres shelled with Fe3O4 and pure Fe3O4 particles, such as the size of the magnetites and the ferromagnetic property. Furthermore, the spheres exhibited the superparamagnetic characterization when the thickness of the Fe3O4 shell was less than 15 nm. PMID:15158391

Huang, Zhongbing; Tang, Fangqiong

2004-07-01

169

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

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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...

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

2013-01-01

170

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

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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

171

Effect of spatial confinement on magnetic hyperthermia via dipolar interactions in Fe3O4 nanoparticles for biomedical applications  

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In this work, the effect of nanoparticle confinement on the magnetic relaxation of iron oxide (Fe3O4) nanoparticles (NP) was investigated by measuring the hyperthermia heating behavior in high frequency alternating magnetic field. Three different Fe3O4 nanoparticle systems having distinct nanoparticle configurations were studied in terms of magnetic hyperthermia heating rate and DC magnetization. All magnetic nanoparticle (MNP) systems were constructed using equivalent ~10nm diameter NP that were structured differently in terms of configuration, physical confinement, and interparticle spacing. The spatial confinement was achieved by embedding the Fe3O4 nanoparticles in the matrices of the polystyrene spheres of 100 nm, while the unconfined was the free Fe3O4 nanoparticles well-dispersed in the liquid via PAA surface coating. Assuming the identical core MNPs in each system, the heating behavior was analyzed in terms of particle freedom (or confinement), interparticle spacing, and magnetic coupling (or dipole-dipole interaction). DC magnetization data were correlated to the heating behavior with different material properties. Analysis of DC magnetization measurements showed deviation from classical Langevin behavior near saturation due to dipole interaction modification of the MNPs resulting in a high magnetic anisotropy. It was found that the Specific Absorption Rate (SAR) of the unconfined nanoparticle systems were significantly higher than those of confined (the MNPs embedded in the polystyrene matrix). This increase of SAR was found to be attributable to high Néel relaxation rate and hysteresis loss of the unconfined MNPs. It was also found that the dipole-dipole interactions can significantly reduce the global magnetic response of the MNPs and thereby decrease the SAR of the nanoparticle systems.

Sadat, M E [University of Cincinnati; Patel, Ronak [University of Cincinnati; Sookoor, Jason [University of Cincinnati; Bud' ko, Sergey L [Ames Laboratory; Ewing, Rodney C [Stanford University; Zhang, Jiaming [Stanford University; Xu, Hong [Shanghai Jiao Tong University; Wang, Yilong [Tongji University School of Medicine; Pauletti, Giovanni M [University of Cincinnati; Mast, David B [University of Cincinnati; Shi, Donglu [University of Cincinnati

2014-09-01

172

Nanocomposite materials based on ZnO and Fe3O4 nanoparticles in a polymer martix  

Science.gov (United States)

The techniques of sample synthesis of four types (the original liquid-phase dispersions of ZnO nanoparticles (NPs) and Fe3O4 NPs, solid nanocomposites ZnO-high-density polyethylene (HDPE) and Fe3O4-HDPE) have been developed. The dispersion of ZnO NPs was obtained by alkaline hydrolysis of zinc acetate potassium hydroxide in isopropyl alcohol. The dispersion of Fe3O4 NPs was prepared via the reaction of aqueous solutions of the iron salts (FeCl2 and FeCl3). After removal of impurity ions the dispersions were introduced into HDPE. A comparative analysis of the characteristics and properties of ZnO and Fe3O4 NPs in the original dispersions and in the polyethylene matrices was carried out by a complex of structural and physical methods (X-ray and electron diffraction, transmission and scanning electron microscopy, X-ray small-angle scattering, photoluminescence, electron magnetic resonance).

Zaporozhets, M. A.; Rustamova, C. G.; Timoshenko, N. S.; Nikolaichik, V. I.; Dembo, K. A.; Savilov, S. V.; Khodos, I. I.; Avilov, A. S.; Gubin, S. P.

2012-02-01

173

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

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Full Text Available Bao-An Chen1, Nan Jin1, Jun Wang1, Jiahua Ding1, Chong Gao1, Jian Cheng1, Guohua Xia1, Feng Gao1, Yin Zhou1, Yue Chen1, Guina Zhou1, Xiaomao Li2, Yu Zhang3, Men Tang3, Xuemei Wang31Department of Hematology, Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Physics, University of Saarland, D-266041 Saarbruechen, Germany; 3National Key Laboratory of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of ChinaAbstract: 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, respectively. The results showed that the ratio of spleen to body weight was not different between the experimental groups and control group (P > 0.05. The lymphocyte transformation rates in the suspension of spleen were higher in low-dose group than those in the control group (P < 0.05, while the proliferation of splenocytes was low in the medium and high groups when compared to the control group (P < 0.05. In peripheral blood, both the proportions of subset CD4+ and CD8+ T lymphocytes in the low-dose group were higher than those in the control group, whereas there was no difference in the number of CD4+ T cells between the medium- and low-dose groups. Interestingly, the Fe3O4-MNPs enhanced the production of interleukin-2 (IL-2, interferon-?, and IL-10 but did not affect the production of IL-4 in peripheral blood. It is concluded that Fe3O4-MNPs could influence immune functions of normal ICR mice in a dose-dependent manner.Keywords: magnetic nanoparticle of Fe3O4, immune function, splenocyte proliferation, cytokine

Bao-An Chen

2010-08-01

174

Magnetic photocatalysts with a p-n junction: Fe3O4 nanoparticle and FeWO4 nanowire heterostructures  

Science.gov (United States)

Magnetic n-type semiconductor Fe3O4 nanoparticle and p-type semiconductor FeWO4 nanowire heterostructures were successfully synthesized without any surfactants or templates via a facile one-step hydrothermal process at 160 °C. The heterojunction structure and morphology were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Magnetic measurements indicated the coexistence of ferrimagnetic behavior of Fe3O4 and weak antiferromagnetic behavior of FeWO4. The degradation of methylene blue (MB) under UV-Visible light irradiation was studied as a model experiment to evaluate the catalytic activity of the Fe3O4/FeWO4 heterostructure p-n junctions. The decomposition efficiency was 97.1% after one hour UV-Visible irradiation. This magnetic photocatalyst can be easily recovered from the solution using a permanent magnet and redispersed by removing the magnet.Magnetic n-type semiconductor Fe3O4 nanoparticle and p-type semiconductor FeWO4 nanowire heterostructures were successfully synthesized without any surfactants or templates via a facile one-step hydrothermal process at 160 °C. The heterojunction structure and morphology were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Magnetic measurements indicated the coexistence of ferrimagnetic behavior of Fe3O4 and weak antiferromagnetic behavior of FeWO4. The degradation of methylene blue (MB) under UV-Visible light irradiation was studied as a model experiment to evaluate the catalytic activity of the Fe3O4/FeWO4 heterostructure p-n junctions. The decomposition efficiency was 97.1% after one hour UV-Visible irradiation. This magnetic photocatalyst can be easily recovered from the solution using a permanent magnet and redispersed by removing the magnet. Electronic supplementary information (ESI) available: The equation used to calculate the energy band gap, XRD data of the products with various pH values, the SEM image of Fe3O4/FeWO4, and the TEM image of FeWO4 nanowires. See DOI: 10.1039/c4nr03729d

Cao, Xuan; Chen, Yan; Jiao, Shihui; Fang, Zhenxing; Xu, Man; Liu, Xu; Li, Lu; Pang, Guangsheng; Feng, Shouhua

2014-10-01

175

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

176

Synthesis of magnetic core-shell Fe3O4-Au nanoparticle for biomolecule immobilization and detection  

International Nuclear Information System (INIS)

The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution using the borohydride reduction of HAuCl4 under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy (TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV-Vis), and X-ray diffraction (XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe3O4 nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface of Fe3O4 particles exhibits uniform Fe3O4-Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated Fe3O4 nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes. Immunomagnetic separation was also performed at different E. coli concentrat performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied in a range of 52.1 and 21.9% depend on the initial bacteria counts.

177

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

178

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

179

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

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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

180

Photoelectron diffraction of Rh nanoparticles growth on Fe3O4/Pd(111) ultra thin film  

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Full text: Heterogeneous catalysis is a highly complex process. Usually, a catalyst is formed by transition metal nanoparticles (for example, Pd, Pt, Rh, Ni, Au) supported by an oxide such as alumina, silica, titania among others [1-4]. The performance of the catalyst in terms of macroscopic chemical parameters such as the temperature for reaction activation, selectivity and efficiency can be strongly influenced by different characteristics of the catalyst at the atomic level, for instance, its electronic and atomic structure, particle size and shape, crystallographic structure [5-6] and support material effects[1]. Metal-oxide-based catalysts are used for many important synthesis reactions in the chemical industry, such as selective oxidation, dehydrogenation, isomerization and other chemical processes [7]. Rhodium nanoparticles have been used, for example, in the studies of propionaldehyde decomposition under ultra-high vacuum (UHV) conditions. The aim of this work is to prepare rhodium nanoparticles on magnetite (Fe3O4) (111) growth on Pd(111). The rhodium clusters and iron oxide ultra-thin films (thickness <10ML) were prepared in UHV conditions by Molecular Beam Epitaxy (MBE) and keeping the substrate at 450 deg C. The system was characterized by X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and photoelectron diffraction (PED) performed at the SGM beam line at the Brazilian Synchrotron Light Source (LNLS). Our results shows the formation of small Rh an island with the same atomic structure of fcc Rh at bulk, and thickness lower then 5MLs. The islands cover approximately 15% of the iron surface. These findings were determined mainly with the PED experiments supported by a comprehensive simulation approach based on multiple scattering calculations. References: [1] J. Libuda, H.-J. Freund, Surf. Sci. Rep. 57, 157 (2005). [2] C. R. Henry, Surf. Sci. Rep. 31, 231 (1998). [3] N. Nilius, A. Corper, G. Bozdech, N. Ernst , H.-J. Freund, Prog. Surf. Sci. 67, 99 (2001). [4] C. T. Campbell, Surf. Sci. Rep. 27, 1 (1997). [5] M. Frank, S. Andersson, J. Libuda, S. Stempel, A. Sandell, B. Brena, A. Giertz, P. A. Bruhwiler, M. Baumer, N. Martensson, H.-J. Freund, Chem. Phys. Lett. 279 92 (1997). [6] S. Andersson, M. Frank, A. Sandell, A. Giertz, B. Brena, P. A. Bruhwiler, N. Martensson, J. Libuda, M. Baumer, H.-J. Freund, J. Chem. Phys. 108 2967 (1998). [7] G. Ertl, H. Knozinger, J. Weitkamp, Handbook of Heterogeneous Catalysis, Wiley-VCH, Weinheim, 1997. (author)

 
 
 
 
181

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 removan be an attractive option for metal removal from industrial effluent.

182

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

183

A Noninvasive Method to Determine the Fate of Fe3O4 Nanoparticles following Intravenous Injection Using Scanning SQUID Biosusceptometry  

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Magnetic nanoparticles (MNPs) of Fe3O4 have been widely applied in many medical fields, but few studies have clearly shown the outcome of particles following intravenous injection. We performed a magnetic examination using scanning SQUID biosusceptometry (SSB). Based on the results of SSB analysis and those of established in vitro nonmagnetic bioassays, this study proposes a model of MNP metabolism consisting of an acute metabolic phase with an 8 h duration that is followed by a chronic metab...

Tseng, Wei-kung; Chieh, Jen-jie; Yang, Yi-fan; Chiang, Chih-kang; Chen, Yuh-lien; Yang, Shieh Yueh; Horng, Herng-er; Yang, Hong-chang; Wu, Chau-chung

2012-01-01

184

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

185

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.

186

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

Science.gov (United States)

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

187

Rapid magnetic solid phase extraction with in situ derivatization of methylmercury in seawater by Fe3O4/polyaniline nanoparticle.  

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A new Fe(3)O(4)/polyaniline nanoparticle (PANI) material has been successfully developed as magnetic solid-phase extraction sorbent in dispersion mode for the determination of methylmercury (MeHg) in aqueous samples, via quantification by gas chromatography/mass spectrometry (GC-MS). The resultant core-shell magnetic solid-phase extraction nanoparticle (MSPE-NP) sorbent was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) and Fourier transform-infrared (FTIR) spectroscopy. Fe(3)O(4)/PANI composites showed fibrous structure with diameters between 50 and 100 nm for fibers. The MSPE-NP process involved the dispersion of the Fe(3)O(4)/PANI nanoparticles in water samples with sonication, followed by magnetic aided retrieval of the sorbent and then, solvent (hexane) desorption of extracted MeHg for GC-MS analysis. The extraction, derivatization and adsorption conditions were optimized by selecting the appropriate extraction parameters including the amount of sorbent, extraction time, derivatizing reagent volume and extraction solvent. The calibration graph was linear in the concentration range of 0.5-300 ng mL(-1) (R(2)>0.993) with detection limit of 0.1 ng mL(-1) (n=3), while the repeatability was 4.1% (n=5). Enrichment factor was obtained as 91. Seawater sample was analyzed as real sample and good recoveries (>98%) were obtained at different spiked values. PMID:21621779

Mehdinia, Ali; Roohi, Fateme; Jabbari, Ali

2011-07-15

188

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.

189

?-Cyclodextrin coated Fe3O4 nanoparticles: a simple preparation and application for selective oxidation of alcohols in water  

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Full Text Available SciELO Brazil | Language: English Abstract in portuguese Um catalisador magnético foi sintetizado via proceso de ativação da carboimida em ?-ciclodextrina funcionalizada com nanopartículas core-shell (Fe3O4/SiO2/CM-?-CD). O catalisador apresenta elevada atividade na oxidação seletiva de vários álcoois usando NaOCl como oxidante e água como solvente. Foi o [...] btido um processo seletivo na ausência de metal de transição e de fácil separação do catalisador. Abstract in english A magnetically separable catalyst was synthesized via a carbodiimide activation process with ?-cyclodextrin functionalized by core-shell nanoparticles (Fe3O4/SiO2/CM-?-CD). The catalyst presented high activity for selective oxidation of various alcohols with NaOCl as oxidant and water only as the so [...] lvent. A substrate-selective and transition metal-free process was achieved with easy separation of the catalyst.

Jie, Zhu; Peng-cheng, Wang; Ming, Lu.

2013-01-01

190

Scalable synthesis of Fe3O4 nanoparticles anchored on graphene as a high-performance anode for lithium ion batteries  

International Nuclear Information System (INIS)

We report a scalable strategy to synthesize Fe3O4/graphene nanocomposites as a high-performance anode material for lithium ion batteries. In this study, ferric citrate is used as precursor to prepare Fe3O4 nanoparticles without introducing additional reducing agent; furthermore and show that such Fe3O4 nanoparticles can be anchored on graphene sheets which attributed to multifunctional group effect of citrate. Electrochemical characterization of the Fe3O4/graphene nanocomposites exhibit large reversible capacity (?1347 mA h g?1 at a current density of 0.2 C up to 100 cycles, and subsequent capacity of ?619 mA h g?1 at a current density of 2 C up to 200 cycles), as well as high coulombic efficiency (?97%), excellent rate capability, and good cyclic stability. High resolution transmission electron microscopy confirms that Fe3O4 nanoparticles, with a size of ?4–16 nm are densely anchored on thin graphene sheets, resulting in large synergetic effects between Fe3O4 nanoparticles and graphene sheets with high electrochemical performance. - Graphical abstract: The reduction of Fe3+ to Fe2+ and the deposition of Fe3O4 on graphene sheets occur simultaneously using citrate function as reductant and anchor agent in this reaction process. Highlights: ? Fe3O4/graphene composites are synthesized directly from graphene and C6H5FeO7. ? The citrate function as reductant and anchor agent in this reaction process. ? The resulting Fe3O4 particles (?4–16 nm) are densely anchored on graphene sheets. ? The prepared Fe3O4/graphene composites exhibit excellent electrochemical performance

191

Rapid and highly efficient preconcentration of Eu(III) by core-shell structured Fe3O4@humic acid magnetic nanoparticles.  

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In this study, humic acid-coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@HA MNPs) were synthesized using a chemical coprecipitation method and characterized in detail. The XRD analysis results showed that HA coating did not change the phase of Fe(3)O(4) cores. The TEM image suggested that Fe(3)O(4)@HA MNPs had nearly uniform size without the observation of aggregation. The Fe(3)O(4)@HA MNPs were stable in solution and could be easily separated from aqueous solution using a magnetic separation method. A batch technique was adopted to investigate the removal efficiency of Fe(3)O(4)@HA MNPs toward Eu(III) under various environmental conditions. The kinetic process of Eu(III) sorption on Fe(3)O(4)@HA MNPs reached equilibrium within sorption kinetics and high sorption amount were attributed to the plentiful surface sites provided by the surface-coated HA macromolecules. The Fe(3)O(4)@HA MNPs was able to remove ~99% of Eu(III) in aqueous solution at pH 8.5. Except for SO(4)(2-) anions, the coexisting electrolyte ions had no significant competition effects on the removal of Eu(III) by Fe(3)O(4)@HA MNPs. The obvious sorption-desorption hysteresis suggested that the removal of Eu(III) was dominated by inner-sphere surface complexation. The sorption isotherm agreed well with the Langmuir model, having a maximum sorption capacity of 6.95 × 10(-5) mol g(-1). The leaching test showed that the Eu(III)-loaded Fe(3)O(4)@HA colloids were capable to maintain high thermodynamic stability for long aging times. The findings herein suggested that Fe(3)O(4)@HA MNPs could be potentially used as a highly effective material for the enrichment and preconcentration of radionuclide Eu(III) or other trivalent lanthanides/actinides in geological repositories or in nuclear waste management. PMID:23182180

Yang, Shitong; Zong, Pengfei; Ren, Xuemei; Wang, Qi; Wang, Xiangke

2012-12-01

192

Ultrasonic Fenton-like catalytic degradation of bisphenol A by ferroferric oxide (Fe3O4) nanoparticles prepared from steel pickling waste liquor.  

Science.gov (United States)

In this study, Fe3O4 NPs (named as Fe3O4 NPs-PO) were prepared by steel pickling waste liquor to reduce the cost of preparation, and were compared with those obtained by the common co-precipitation method (named as Fe3O4 NPs-CP) which prepared from chemical reagent using BET, XRD, XPS, TEM and SEM techniques. The results indicated that Fe3O4 NPs-PO nanoparticles mainly existed in the form of Fe3O4 and appeared to be roughly spherical in shape with a size range of 20-50nm. The heterogeneous Fenton-like catalytic capacity of Fe3O4 NPs-PO in US+Fe3O4+H2O2 system was comprehensively investigated. BPA could be degraded within a wide pH range of 7-10. The removal efficiencies of BPA were close to 100% and about 45% total organic carbon (TOC) in solution was eliminated at the optimized conditions. It was found that·OH radicals which mainly caused the degradation of BPA were promptly generated due to the catalysis of the Fe3O4 NPs-PO. Furthermore, the comparative study of catalytic activity, stability and reusability between Fe3O4 NPs-PO and Fe3O4 NPs-CP showed that the two catalysts both remained good activity after several reaction cycles and no significant change in composition and structure was observed, the loss of catalyst was negligible, which demonstrated that Fe3O4 NPs-PO were promising in ultrasonic Fenton-like process to treat refractory organics. PMID:25280370

Huang, Ruixiong; Fang, Zhanqiang; Fang, Xiaobo; Tsang, Eric Pokeung

2014-12-15

193

Thermal annealing synthesis of Fe4N/Fe nanocomposites from iron oxide (Fe3O4) nanoparticles  

Science.gov (United States)

A facile sono-thermal approach using inexpensive and non-toxic chemicals was applied for the large-scale synthesis of iron nitride/iron (Fe4N/Fe) nanocomposite. The as-synthesized iron oxide (Fe3O4) nanoparticles by sonochemical method were treated in a thermal annealing chamber in presence of hydrogen (H2) and ammonia (NH3) gases to obtain Fe4N/Fe nanocomposite. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses revealed that the Fe4N/Fe nanocomposite had been successfully synthesized using this simple method. Transmission electron microscopy (TEM) data demonstrated that the sizes of the as-synthesized Fe4N/Fe nanocomposite were larger compared to the sizes for the initial Fe3O4 NPs. The magnetization curve obtained using vibrating sample magnetometer (VSM) measurements showed that the magnetization had been significantly increased in the synthesized Fe4N/Fe nanocomposite compared to that in the freshly-prepared Fe3O4 magnetic NPs.

Islam, Md. Nazrul; Abbas, Mohamed; Kim, Kun Woo; Kim, CheolGi

2014-11-01

194

Quantitative Determination of 3-Aminopropylsilane on the Surface of FE3O4 Nanoparticles by Attenuated Total Reflection Infrared Spectroscopy  

Science.gov (United States)

A technique for quantitative analysis of 3-aminopropylsilane on the surface of chemically modified Fe3O4 magnetic nanoparticles in the concentration range 0.32-3.03 mmol/g was developed using attenuated total reflection infrared spectroscopy. The technique was based on the ratios of band areas corresponding to Fe-O vibrations of the nanoparticles and Si-O vibrations of the coating as a function of the Si mass fraction in the nanocomposite that was determined by inductively coupled plasma atomic-emission spectroscopy.

Demin, A. M.; Koryakova, O. V.; Krasnov, V. P.

2014-09-01

195

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

International Nuclear Information System (INIS)

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 expewas 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.

196

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

International Nuclear Information System (INIS)

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

197

A novel solvethermal method for the preparation of magnetic monodisperse Fe3O4 nanoparticles II: High-surface-activity ferrihydrite used as precursor  

International Nuclear Information System (INIS)

Graphical abstract: The magnetic monodisperse Fe3O4 nanoparticles (NPs) were prepared by novel solvethemal method at moderate temperature using high surface active ferrihydrit and iron powder as precursors in orgnic solvent. - Highlights: • Facile synthesis of organic ligands-coated monodisperse Fe3O4 nanoparticles at low temperature. • Low-cost high surface active ferrihydrit and reductive iron powder were used as precursors. • N2-free reaction environment. • Organic ligands act as reductive. - Abstract: Magnetic monodisperse Fe3O4 nanoparticles (NPs) were prepared from ferrihydrite and iron powder by a novel solvethermal method at moderate temperatures in aqueous and organic solvent media. The effects of temperature and solvent medium on the phase and particle size of Fe3O4 NPs were investigated. The products were characterized by X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry–thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. At 120 °C in the organic medium, uniform organic-ligand-coated superparamagnetic Fe3O4 NPs were produced; the particle size increased with the temperature, and the calculated mean particle size was 8.9 nm. At 180 °C in the aqueous medium, pure-phase Fe3O4 was obtained. Thus, the organic solvent did not only serve as a solvent but also participated in the reaction. Fe3O4 production in the aqueous and organic solvent media had different mechanisms

198

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

Science.gov (United States)

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

199

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

200

Synthesis and properties of Fe3O4-activated carbon magnetic nanoparticles for removal of aniline from aqueous solution: equilibrium, kinetic and thermodynamic studies  

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In this study, powder activated carbon (PAC) and magnetic nanoparticles of iron (III) oxide were used for synthesis of Fe3O4-activated carbon magnetic nanoparticles (AC-Fe3O4 MNPs) as an adsorbent for the removal of aniline. The characteristics of adsorbent were evaluated by SEM, TEM, XRD and BET. Also, the impact of different parameters such as pH, contact time, adsorbent dosage, aniline initials concentration and solution temperature were studied. The experimental data investigated by Langm...

Babak Kakavandi; Ahmad Jonidi; Roshanak Rezaei; Simin Nasseri; Ahmad Ameri; Ali Esrafily

2013-01-01

 
 
 
 
201

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

202

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

203

Determination of concentration of 3-aminopropylsilane on surface of Fe3O4 nanoparticles by infrared attenuated total reflection spectroscopy  

International Nuclear Information System (INIS)

A technique for the quantitative analysis of 3-aminopropylsilane on the surface of modified Fe3O4 magnetic nanoparticles in the concentration range of 0.32-3.03 mmol/g was developed using the infrared attenuated total reflection spectroscopy. The technique is based on a ratio of areas of the bands corresponding to Fe-O bond vibrations of the core and to Si-O bond vibrations of the shell depending on silicon mass fraction in the analyzed nanocomposite. The fraction was measured by the inductively coupled plasma emission spectrometry. (authors)

204

Investigation of electric field effect on the third order nonlinear optical properties of Fe3O4 nanoparticles-doped nematic liquid crystal  

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Third order nonlinearity of Fe3O4 nanoparticles (NPs) doped in nematic liquid crystals (NLCs) was evaluated due to laser induced self-phase modulation. The influence of electric field on the nonlinear optical responses of the NLCs doped with Fe3O4 NPs was considered in different voltages. The measurements were performed for two commonly initial alignments (homogeneous and homeotropic) with different small compositional percentages of magnetic NPs. The experimental results show that the homogenous- aligned cell was considerably affected on the applied electric field while the nonlinearity of homeotropic-aligned NLCs with the Fe3O4 NPs did not approximately change in the presence of electric field.

Dehghani, Z.; Saievar Iranizad, E.; Nadafan, M.

2015-01-01

205

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

206

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

207

Scalable synthesis of Fe3O4 nanoparticles anchored on graphene as a high-performance anode for lithium ion batteries  

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We report a scalable strategy to synthesize Fe3O4/graphene nanocomposites as a high-performance anode material for lithium ion batteries. In this study, ferric citrate is used as precursor to prepare Fe3O4 nanoparticles without introducing additional reducing agent; furthermore and show that such Fe3O4 nanoparticles can be anchored on graphene sheets which attributed to multifunctional group effect of citrate. Electrochemical characterization of the Fe3O4/graphene nanocomposites exhibit large reversible capacity (˜1347 mA h g-1 at a current density of 0.2 C up to 100 cycles, and subsequent capacity of ˜619 mA h g-1 at a current density of 2 C up to 200 cycles), as well as high coulombic efficiency (˜97%), excellent rate capability, and good cyclic stability. High resolution transmission electron microscopy confirms that Fe3O4 nanoparticles, with a size of ˜4-16 nm are densely anchored on thin graphene sheets, resulting in large synergetic effects between Fe3O4 nanoparticles and graphene sheets with high electrochemical performance.

Dong, Yu Cheng; Ma, Ru Guang; Jun Hu, Ming; Cheng, Hua; Tsang, Chun Kwan; Yang, Qing Dan; Yang Li, Yang; Zapien, Juan Antonio

2013-05-01

208

A novel green synthesis of Fe3O4-Ag core shell recyclable nanoparticles using Vitis vinifera stem extract and its enhanced antibacterial performance  

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We described a novel and eco-friendly method for preparing Fe3O4-Ag core shell nanoparticles (CSNPs) with high magnetism and potent antibacterial activity. The Fe3O4-Ag CSNPs were obtained using waste material of Vitis vinifera (grape) stem extract as the green solvent, reducing and capping agent. The result recorded from X-ray powder diffraction (XRD), UV-vis spectrum, energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) supports the biosynthesis and characterization of Fe3O4-Ag CSNPs. From transmission electron microscopy (TEM) the size of the Fe3O4-Ag nanoparticles was measured below 50 nm; high-resolution TEM (HRTEM) indicates the core shell structure; and selected area electron diffraction (SAED) has revealed polycrystalline nature. Vibrating sample magnetometer (VSM) shows the ferromagnetic nature of Fe3O4-Ag CSNPs at room temperature with saturation magnetization of 15.74 emu/g. Further, these biogenic nanoparticles were highly hazardous to microorganisms. The antibacterial activity of biogenic Fe3O4-Ag CSNPs showed potent inhibitory activity against both Gram-positive and Gram-negative pathogens. These nanoparticles may also be reusable because of its excellent ferromagnetic property.

Venkateswarlu, Sada; Natesh Kumar, B.; Prathima, B.; Anitha, K.; Jyothi, N. V. V.

2015-01-01

209

Multifunctional superparamagnetic fe3O4@SiO2 core/shell nanoparticles: design and application for cell imaging.  

Science.gov (United States)

Highly biocompatible sub-50-nm monodisperse superparamagnetic Fe3O4@SiO2 core/shell nanoparticles with luminescent silica shells were synthesized by a w/o-microemulsion technique. And then these nanoparticles were coated with the covalently bonded biocompatible polymer poly(ethylene glycol) (PEG) and modified with the biological cancer targeting ligand folic acid (FA). After characterized by means of powder X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transformed infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), UV-vis, fluorescence spectroscopy and confocal laser scanning microscopy (CLSM), we confirmed that Fe3O4@SiO2 (FITC)-PEG-FA nanocomposites (SMNPs-FA) could be efficiently taken up by HeLa cancer cells and KB cells which are of over-expression of folate receptors. The multifunctional nanomaterials exhibited superparamagnetic, monodisperse, highly biocompatible, intensively fluorescent and capable of recognizing and binding cells that overexpress folate receptors, which would be useful for targeting cell imaging and provide an excellent platform for further development of an efficient cancer therapy. PMID:24738334

Zhao, Xueling; Zhao, Hongli; Yuan, Huihui; Lan, Minbo

2014-02-01

210

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

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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.

Qin, Huan; Xu, Dong; Yang, Sihua

2011-01-01

211

Radiolytic formation of Fe3O4 nanoparticles: influence of radiation dose on structure and magnetic properties.  

Science.gov (United States)

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. PMID:24608715

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

2014-01-01

212

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

213

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.

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

2013-11-15

214

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

Science.gov (United States)

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

215

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

Science.gov (United States)

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

216

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

217

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

218

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

Directory of Open Access Journals (Sweden)

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

219

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

220

A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe3O4 and CdS nanoparticles  

International Nuclear Information System (INIS)

Novel sulfonated polystyrene microsphere containing Fe3O4 and CdS nanoparticles have been prepared and characterized. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, VSM data, EDS, and photoluminescence spectroscopy. The presence of the magnetic nanoparticles (Fe3O4) and CdS nanoparticles on the polystyrene microspheres has been demonstrated. Cadmium diethyl dithiophosphate (CDDP) has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality CdS nanoparticles on polystyrene microsphere containing Fe3O4 nanoparticles. This novel composite exhibits both fluorescence and magnetism properties that may be used in a novel bioprobe.

 
 
 
 
221

A novel magneto-fluorescent microsphere: Preparation and characterization of polystyrene-supported Fe3O4 and CdS nanoparticles  

Science.gov (United States)

Novel sulfonated polystyrene microsphere containing Fe3O4 and CdS nanoparticles have been prepared and characterized. A thorough structural characterization has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, VSM data, EDS, and photoluminescence spectroscopy. The presence of the magnetic nanoparticles (Fe3O4) and CdS nanoparticles on the polystyrene microspheres has been demonstrated. Cadmium diethyl dithiophosphate (CDDP) has been used as a 3 in 1 precursor (cadmium, sulfur, and ligand source) for the synthesis of high-quality CdS nanoparticles on polystyrene microsphere containing Fe3O4 nanoparticles. This novel composite exhibits both fluorescence and magnetism properties that may be used in a novel bioprobe.

Kaboudin, Babak; Ghaderian, Abolfazl

2013-10-01

222

Selective adsorption of Cr(VI) from aqueous solution by EDA-Fe3O4 nanoparticles prepared from steel pickling waste liquor  

Science.gov (United States)

In this study, Fe3O4 nanoparticles (NPs) prepared from steel pickling waste liquor were functionalized with ethylenediamine (EDA) to form EDA-Fe3O4 NPs for engineering applications. The obtained EDA-Fe3O4 NPs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface analyzer and Fourier-transform infrared (FTIR) spectroscopy. The results showed that the EDA-Fe3O4 NPs had a crystalline structure with a particle size range of 20-50 nm and a BET surface area of 28 m2 g-1. Functionalization with EDA was able to improve the adsorption selectivity of Fe3O4 for Cr(VI) in Cr(VI)/Cl-or Cr(VI)/SO42- double-mixture systems. The adsorption isotherm data fitted better to the Langmuir adsorption model, and the adsorption kinetics was better described by the pseudo-second order equation. The spontaneous and endothermic characteristics of this adsorption reaction were confirmed by thermodynamic study. Based on the results of X-ray photoelectron spectroscopy (XPS), electrostatic attraction and surface complexation between Cr(VI) and EDA-Fe3O4 NPs are postulated as mechanisms for the adsorption of Cr(VI) from aqueous solution. The EDA-Fe3O4 NPs retained a high adsorption capacity after several consecutive adsorption-desorption processes, indicating that EDA-Fe3O4 NPs serve as an excellent regenerable adsorbent for Cr(VI).

Fang, X. B.; Fang, Z. Q.; Tsang, P. K. E.; Cheng, W.; Yan, X. M.; Zheng, L. C.

2014-09-01

223

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..

224

The effect of suspended Fe3O4 nanoparticle size on magneto-optical properties of ferrofluids  

Science.gov (United States)

We investigate the effect of hydrodynamic particle size on the magnetic field induced light transmission and transmitted speckle pattern in water based ferrofluids containing functionalized Fe3O4 nanoparticles of size ranging from 15 to 46 nm. Three water-based magnetic nanofluids, containing Fe3O4 nanoparticles functionalized with poly-acrylic acid (PAA), tetra-methyl ammonium hydroxide (TMAOH) and phosphate, are used in the present study. In all three cases, the transmitted light intensity starts decreasing above a certain magnetic field (called first critical field) and becomes a minimum at another field (second critical field). These two critical fields signify the onset of linear aggregation process and zippering transitions between fully grown chains, respectively. Both these critical fields shift towards a lower magnetic field with increasing hydrodynamic diameter, due to stronger magnetic dipolar interactions. The first and the second critical fields showed a power law dependence on the hydrodynamic diameters. The dipolar resonances occurring at certain values of the scatterer size, leads to the field induced extinction of light. Both the onset of chaining and zippering transitions were clearly evident in the time dependent transmitted light intensity. Above the first critical field, the lobe part of the transmitted intensity and the lobe speckle contrast values increase with increasing external magnetic field due to reduced Brownian motion of the field induced aggregates. The speckle contrast was highest for nanoparticle with the largest hydrodynamic diameter, due to reduced Brownian motion. These results provide better insight into field dependent light control in magnetic colloids, which may find interesting applications in magneto-optical devices.

Brojabasi, Surajit; Muthukumaran, T.; Laskar, J. M.; Philip, John

2015-02-01

225

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 ?6 nm 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(?)=123.65 mM(-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

226

Chitosan-coated ferrite (Fe3O4) nanoparticles as a T2 contrast agent for magnetic resonance imaging  

International Nuclear Information System (INIS)

Iron oxide (Fe3O4) nanoparticles coated with biocompatible chitosan were synthesized for use as an MRI (magnetic resonance imaging) contrast agent. The coating was performed simultaneously with the synthesis of the ferrite nanoparticles. A dynamic light-scattering spectrometer (DLS) and a transmission electron microscope (TEM) were used to measure the average diameter of the coated nanoparticles, which was 67.0 nm. Fourier transform infrared (FT-IR) measurements showed strong bonding of the chitosan molecules to the surfaces of the ferrite nanoparticles. The spin-lattice (T1) and the spin-spin (T2) relaxation times of the nuclear spins (hydrogen protons) in aqueous solutions of various concentrations of coated ferrite nanoparticles were determined using a nuclear magnetic resonance (NMR) spectrometer. Using these data, we found that the T1 and the T2 relaxivities of the nuclear spins in aqueous solutions of ferrite nanoparticles were 0.00291 and 0.0691 ppm-1sec-1, respectively. In particular, the value of the T2 relaxivity was much larger than that of the commercial contrast agent GD-DTPA (gadolinium diethylenetriamine penta-acetic acid). A 31.7% intensity loss in the T2 image of a rabbit liver was observed after injecting the aqueous solution of coated nanoparticles into the rabbit, which shows that our coated ferrite nanoparticles can be used as a T22 MRI contrast agent.

227

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)

228

Size and Correlation Analysis of Fe3O4 Nanoparticles in Magnetic Fluids by Small-Angle Neutron Scattering  

Science.gov (United States)

Size and correlation analyses of Fe3O4 nanoparticles have been carried out by the measurement of small angle neutron scattering. Particle size of magnetite is analyzed by employing Guinier region approximation in order to obtain gyration radius, which will be used to further determine the average radius of magnetite particles resulting in the value between 17.8 nm and 53.6 nm. Further approximation using a polycore-shell ratio model shows the average particle size of 25 nm with polydispersity of 0.4. The effect of magnetic fluids concentration on the thickness of surfactant layer on the particles surface has not shown a significant change with the value between 6 ? and 8 ? relating to the molar concentration between 0.5 M and 3 M, signifying no correlation among the particles in magnetic fluids.

Ani, S. A.; Pratapa, S.; Purwaningsih, S.; Triwikantoro, Darminto, Putra, E. Giri Rachman; Ikram, A.

2008-03-01

229

A remote-activated shape memory polymer network employing vinyl-capped Fe3O4 nanoparticles as netpoints for durable performance  

Science.gov (United States)

A new type of shape memory polymer (SMP) employing vinyl-capped Fe3O4 nanoparticles as netpoints that determine the permanent shape for remote activation has been presented. The new design effectively prevents the nanoparticles from moving and re-aggregating in a polymer matrix and guarantees the stability of the SMP networks when a high temperature and external stress are applied. Therefore, durable shape memory performance is obtained during the programmed deformation-recovery processes. Meanwhile, a homogeneous distribution of vinyl-capped Fe3O4 nanoparticles achieves uniform heat generation and heat transfer in the alternating magnetic field. Consequently, the novel remote-activated SMP also exhibits a fast magnetic responsiveness compared to the SMPs physically dispersed with Fe3O4 nanoparticles.

Xia, Shuang; Li, Xingjian; Wang, Yaru; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin; Peng, Yuxing

2014-08-01

230

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.

231

Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier  

International Nuclear Information System (INIS)

Highlights: ? Ionic liquids modify the dye-adsorption characteristics of magnetic nanoparticles. ? Modified nanoparticles improved the sensitivity of dye measurements. ? Water-solubility is an important factor for choosing an ionic liquid as a modifier for nanoparticles. - Abstract: The nanoparticles of Fe3O4 as well as the binary nanoparticles of ionic liquid and Fe3O4 (IL-Fe3O4) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe3O4 nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60 mg, a pH of 2.5, and a contact time of 2 min when initial dyes concentrations of 10-200 mg L-1 were used. The maximum adsorption capacity of IL-Fe3O4 was 166.67 and 49.26 mg g-1 for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Lata than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62 L mg-1 for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe3O4 by using a mixed NaCl-acetone solution and adsorbent was reusable.

232

Immobilization of Horseradish Peroxidase on NH2-Modified Magnetic Fe3O4/SiO2 Particles and Its Application in Removal of 2,4-Dichlorophenol  

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Fe3O4 nanoparticles were prepared by a co-precipitation method with the assistance of ultrasound irradiation, and then coated with silica generated by hydrolysis and condensation of tetraethoxysilane. The silica-coated Fe3O4 nanoparticles were further modified with 3-aminopropyltriethoxysilane, resulting in anchoring of primary amine groups on the surface of the particles. Horseradish peroxidase (HRP) was then immobilized on the magnetic core-shell particles by using glutaraldehyde as a cross...

Qing Chang; Heqing Tang

2014-01-01

233

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

234

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

235

Novel electrochemical sensor based on N-doped carbon nanotubes and Fe3O4 nanoparticles: simultaneous voltammetric determination of ascorbic acid, dopamine and uric acid.  

Science.gov (United States)

A new modified electrode based on N-doped carbon nanotubes functionalized with Fe3O4 nanoparticles (Fe3O4@CNT-N) has been prepared and applied on the simultaneous electrochemical determination of small biomolecules such as dopamine (DA), uric acid (UA) and ascorbic acid (AA) using voltammetric methods. The unique properties of CNT-N and Fe3O4 nanoparticles individually and the synergetic effect between them led to an improved electrocatalytic activity toward the oxidation of AA, DA and UA. The overlapping anodic peaks of these three biomolecules could be resolved from each other due to their lower oxidation potentials and enhanced oxidation currents when using the Fe3O4@CNT-N modified electrode. The linear response ranges for the square wave voltammetric determination of AA, DA and UA were 5-235, 2.5-65 and 2.5-85?moldm(-3) with detection limit (S/N=3) of 0.24, 0.050 and 0.047?moldm(-3), respectively. These results show that Fe3O4@CNT-N nanocomposite is a promising candidate of cutting-edge electrode materials for electrocatalytic applications. PMID:25086716

Fernandes, Diana M; Costa, Marta; Pereira, Clara; Bachiller-Baeza, Belén; Rodríguez-Ramos, Inmaculada; Guerrero-Ruiz, Antonio; Freire, Cristina

2014-10-15

236

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

237

Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe3O4 magnetic nanoparticles using ionic liquid as modifier.  

Science.gov (United States)

The nanoparticles of Fe(3)O(4) as well as the binary nanoparticles of ionic liquid and Fe(3)O(4) (IL-Fe(3)O(4)) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe(3)O(4) nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60mg, a pH of 2.5, and a contact time of 2min when initial dyes concentrations of 10-200mg L(-1) were used. The maximum adsorption capacity of IL-Fe(3)O(4) was 166.67 and 49.26mg g(-1) for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62L mg(-1) for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe(3)O(4) by using a mixed NaCl-acetone solution and adsorbent was reusable. PMID:21645968

Absalan, Ghodratollah; Asadi, Mozaffar; Kamran, Sedigheh; Sheikhian, Leila; Goltz, Douglas M

2011-08-30

238

Human serum albumin-modified Fe3O4 magnetic nanoparticles for affinity-SALDI-MS of small-molecule drugs in biological liquids.  

Science.gov (United States)

Here, we report on the use of human serum albumin (HSA)-modified Fe(3)O(4) nanoparticles (NPs) (HSA-Fe(3)O(4) NPs) for affinity-SALDI-MS of small drugs in human biological liquids. We demonstrated that HSA-Fe(3)O(4) NPs effectively captured small drugs from human urine and serum via the interactions between HSA and these drugs. The drugs adsorbed on HSA could then be identified by directly introducing the HSA-Fe(3)O(4) NPs into a mass spectrometer for SALDI-MS analysis. The ability of HSA to interact with multiple small drugs facilitated the simultaneous detection of a 4-drug-mixture in serum, viz., phenytoin, ibuprofen, camptothecin, and warfarin sodium, by affinity-SALDI-MS using HSA-Fe(3)O(4) NPs. In contrast, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) with an organic matrix could detect only warfarin sodium. We also demonstrated the capacity of affinity-SALDI-MS to quantify warfarin sodium in urine samples across a range of 50 - 1000 ?M (R(2) = 0.998) when using HSA-Fe(3)O(4) NPs. The detection sensitivity was further improved to a range of 5 - 100 ?M (R(2) = 0.999) by using denatured HSA. The open structure of denatured HSA may enhance the effective extraction of small drugs from biological liquids, and increase the detection-sensitivity of affinity-SALDI-MS. Affinity-SALDI-MS using protein-modified Fe(3)O(4) NPs can open up new approaches to the analytical detection of small drugs in biological liquids by SALDI-MS. PMID:22975918

Iwaki, Yuichi; Kawasaki, Hideya; Arakawa, Ryuichi

2012-01-01

239

Magnetization spectroscopy of biocompatible magnetite (Fe3O4) nanoparticles for MPI  

Science.gov (United States)

We report the use of a nanoparticle magnetization spectrometer to measure the suitability of magnetite nanoparticles for magnetic particle imaging (MPI). The spectrometer, which measures the strength of harmonics in the magnetization of magnetic nanoparticles, produces a driving field at 25 kHz and measures up to 40 harmonics (1Mhz bandwidth). Large, uniform, single-core magnetite particles with diameter ranging from 17 to 22 nm were synthesized for this work and their magnetization spectra were compared with a commercially available option, Resovist. The driving field amplitude was varied and spectra were acquired for field amplitudes ranging from 9.7 to 18.6 mT?0-1. Compared with Resovist, synthesized particles showed increased harmonic power over the full measured frequency range at each driving field.

Ferguson, R. Matthew; Khandhar, Amit P.; Krishnan, Kannan M.

2011-03-01

240

Bifunctional nanoparticles constructed using one-pot encapsulation of a fluorescent polymer and magnetic (Fe3O4) nanoparticles in a silica shell.  

Science.gov (United States)

Integration of biocompatible silica with a fluorescent polymer (PDDF) and superparamagnetic iron oxide nanoparticles (Fe3 O4 ) to form uniform core-shell nanostructures has the great potential to form particles for use in multimodal bioimaging applications. Core-shell nanoparticles (PDDF/Fe3 O4 @SiO2 ) exhibit fluorescent and magnetic properties that are favorable for their use in magnetic separation and guiding applications, as well as optical and magnetic resonance (MR) imaging capabilities. With the biological analysis in an in vitro intracellular permeation and cytotoxicity test, chemical conjugation of the surface using folic acid (FA) molecules can provide the nanoparticles with cell-targeting properties, localizing the nanoparticles to folate receptors (FRs) on target KB cells that over-express the FRs. PMID:23281296

Lee, Chang-Soo; Chang, Hee Hyun; Bae, Pan-Kee; Jung, Juyeon; Chung, Bong Hyun

2013-03-01

 
 
 
 
241

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, th 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.

242

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

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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

243

Removal of Cu(II) and fulvic acid by graphene oxide nanosheets decorated with Fe3O4 nanoparticles.  

Science.gov (United States)

Graphene oxide/Fe(3)O(4) (GO/Fe(3)O(4)) composites were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The removal of Cu(II) and a natural organic macromolecule (fulvic acid (FA)) by GO/Fe(3)O(4) was investigated. The mutual effects of FA/Cu(II) on Cu(II) and FA sorption onto GO/Fe(3)O(4), as well as the effect of pH, ionic strength, FA/Cu(II) concentrations, and the addition sequences of FA/Cu(II) were examined. The results indicated that Cu(II) sorption on GO/Fe(3)O(4) were strongly dependent on pH and independent of ionic strength, indicating that the sorption was mainly dominated by inner-sphere surface complexation rather than outer-sphere surface complexation or ion exchange. The presence of FA leads to a strong increase in Cu(II) sorption at low pH and a decrease at high pH, whereas the presence of Cu(II) led to an increase in FA sorption. The adsorbed FA contributes to the modification of sorbent surface properties and partial complexation of Cu(II) with FA adsorbed. Different effects of FA/Cu(II) concentrations and addition sequences on Cu(II) and FA sorption were observed, indicating the difference in sorption mechanisms. After GO/Fe(3)O(4) adsorbed FA, the sorption capacity for Cu(II) was enhanced at pH 5.3, and the sorption capacity for FA was also enhanced after Cu(II) sorption on GO/Fe(3)O(4). These results are important for estimating and optimizing the removal of metal ions and organic substances by GO/Fe(3)O(4) composites. PMID:22950475

Li, Jie; Zhang, Shouwei; Chen, Changlun; Zhao, Guixia; Yang, Xin; Li, Jiaxing; Wang, Xiangke

2012-09-26

244

Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping  

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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

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Systematic evaluation of biocompatibility of magnetic Fe3O4 nanoparticles with six different mammalian cell lines  

International Nuclear Information System (INIS)

This article systematically evaluated the biocompatibility of multiple mammalian cell lines to 11-nm DMSA-coated Fe3O4 magnetic nanoparticles (MNPs). Cells including RAW264.7, THP-1, Hepa1-6, HepG2, HL-7702, and HeLa were incubated with six different concentrations (0, 20, 30, 40, 50, and 100 ?g/mL) of MNPs for 48 h, and then the cell labeling, iron loading, cell viability, apoptosis, cycle, and oxidative stress were all quantitatively evaluated. The results revealed that all the cells were effectively labeled by the nanoparticles; however, the iron loading of RAW264.7 was significantly higher than that of other cells at any dose. The proliferations of all the cells were not significantly suppressed by MNPs at the studied dose except HepG2 that was exposed to 100 ?g/mL MNPs. The investigation of oxidative stress demonstrated that the levels of total superoxide dismutase and xanthine oxidase had no significant changes in all the cells treated by all the doses of MNPs, while the levels of malonyldialdehyde activity of MNP-treated cells significantly increased. The nanoparticles did not produce any significant effect on cell cycles at any of the doses, but resulted in significant apoptosis of THP-1 and HepG2 cells at the highest concentration of 100 ?g/mL. At a concentration of 30 ?g/mL which was used in human studies with an intravascular nanoparticle imaging agent (Combidex), the nanoparticles efficiently labeled all the cells studied, but didlabeled all the cells studied, but did not produce any significant influence on their viability, oxidative stress, and apoptosis and cycle. Therefore, the nanoparticles were concluded with better biocompatibility, which provided some useful information for its clinical applications.

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

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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

247

Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe3O4 Magnetic Nanoparticle Bio-Complex Film  

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Full Text Available A DNA/chitosan-Fe3O4 magnetic nanoparticle bio-complex film was constructed for the immobilization of horseradish peroxidase (HRP on a glassy carbon electrode. HRP was simply mixed with DNA, chitosan and Fe3O4 nanoparticles, and then applied to the electrode surface to form an enzyme-incorporated polyion complex film. Scanning electron microscopy (SEM was used to study the surface features of DNA/chitosan/Fe3O4/HRP layer. The results of electrochemical impedance spectroscopy (EIS show that Fe3O4 and enzyme were successfully immobilized on the electrode surface by the DNA/chitosan bio-polyion complex membrane. Direct electron transfer (DET and bioelectrocatalysis of HRP in the DNA/chitosan/Fe3O4 film were investigated by cyclic voltammetry (CV and constant potential amperometry. The HRP-immobilized electrode was found to undergo DET and exhibited a fast electron transfer rate constant of 3.7 s?1. The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP(Fe(III and HRP(Fe(II. The obtained electrode also displayed an electrocatalytic reduction behavior towards H2O2. The resulting DNA/chitosan/Fe3O4/HRP/glassy carbon electrode (GCE shows a high sensitivity (20.8 A·cm?2·M?1 toward H2O2. A linear response to H2O2 measurement was obtained over the range from 2 µM to 100 µM (R2 = 0.99 and an amperometric detection limit of 1 µM (S/N = 3. The apparent Michaelis-Menten constant of HRP immobilized on the electrode was 0.28 mM. Furthermore, the electrode exhibits both good operational stability and storage stability.

Tingting Gu

2014-02-01

248

Dielectric study of Al3+ substituted Fe3O4 ferrite nanoparticles  

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

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

2014-07-01

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Developing Fe3O4 nanoparticles into an efficient multimodality imaging and therapeutic probe  

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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

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Fluorescence-based immunoassay for human chorionic gonadotropin based on polyfluorene-coated silica nanoparticles and polyaniline-coated Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

We report on an ultrasensitive fluorescence immunoassay for human chorionic gonadotrophin antigen (hCG). It is based on the use of silica nanoparticles coated with a copolymer (prepared from a fluorene, a phenylenediamine, and divinylbenzene; PF.SiO2) that acts as a fluorescent label for the secondary monoclonal antibody to ?-hCG antigen. In parallel, Fe3O4 nanoparticles were coated with polyaniline, and these magnetic particles (Fe3O4.PANI) served as a solid support for the primary monoclonal antibody to ?-hCG antigen. The PF.SiO2 exhibited strong fluorescence and good dispersibility in water. A fluorescence sandwich immunoassay was developed that enables hCG concentrations to be determined in the 0.01–100 ng·mL?1 concentration range, with a detection limit of 3 pg·mL?1. (author)

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

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Full Text Available 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 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 were assigned randomly into five groups which were treated with normal saline; DNR; NP-Fe3O4 combined with DNR; 5-BrTet combined with DNR; 5-BrTet and MNP-Fe3O4 combined with DNR, respectively. The incidence of formation, growth characteristics, weight, and volume of tumors were observed. The histopathologic examination of tumors and organs were detected. For resistant tumors, the protein levels of Bcl-2, and BAX were detected by Western blot. Bcl-2, BAX, and caspase-3 genes were also detected. For K562/A02 cells xenograft tumors, 5-BrTet and MNP-Fe3O4 combined with DNR significantly suppressed growth of tumor. A histopathologic examination of tumors clearly showed necrosis of the tumors. Application of 5-BrTet and MNP-Fe3O4 inhibited the expression of Bcl-2 protein and upregulated the expression of BAX and caspase-3 proteins in K562/A02 cells xenograft tumor. It is concluded that 5-BrTet and MNP-Fe3O4 combined with DNR had a significant tumor-suppressing effect on a MDR leukemia cells xenograft model.Keywords: 5-bromotetrandrine, magnetic nanoparticle of Fe3O4, multidrug-resistance, xenograft model

Baoan Chen

2009-03-01

252

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

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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

253

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

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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

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

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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

255

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

256

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 (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

257

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples  

Science.gov (United States)

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00 ?g mL-1, 5.0 ng mL-1, 0.9993 and 2.8% (n = 3, c = 4.00 ?g mL-1), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples.

Chen, Jieping; Zhu, Xiashi

2015-02-01

258

Ionic liquid coated magnetic core/shell Fe3O4@SiO2 nanoparticles for the separation/analysis of linuron in food samples.  

Science.gov (United States)

Three hydrophobic ionic liquids (ILs) including 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluorophosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluoro-phosphate ([OMIM]PF6) coated Fe3O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (Fe3O4@SiO2@ILs) and establish a new method of magnetic solid phase extraction (MSPE) coupled with UV spectrometry for separation/analysis of linuron. The results showed that linuron was adsorbed rapidly by Fe3O4@SiO2@[OMIM]PF6 and eluanted by ethanol. Under the optimal conditions, preconcentration factor of the proposed method was 10-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.04-20.00?gmL(-1), 5.0ngmL(-1), 0.9993 and 2.8% (n=3, c=4.00?gmL(-1)), respectively. The Fe3O4@SiO2 nanoparticles could be used repeatedly for 10 times. This proposed method has been successfully applied to the determination of linuron in food samples. PMID:25238184

Chen, Jieping; Zhu, Xiashi

2015-02-25

259

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

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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

260

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

 
 
 
 
261

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.

262

A facile and flexible process of ?-cyclodextrin grafted on Fe3O4 magnetic nanoparticles and host-guest inclusion studies  

International Nuclear Information System (INIS)

In this study, a kind of novel surface-functionalized magnetic nanoparticles was fabricated by the Fe3O4 nanoparticles surface modification with mono-6-deoxy-6-(p-tolylsulfonyl)-cyclodextrin (6-TsO-?-CD), which were employed to interact with uric acid and their behavior was investigated by electrochemical methods. The architecture has been characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA), which confirmed that cyclodextrins have been effectively functionalized on the surface of Fe3O4 nanoparticles. The analyses of vibration sample magnetometer (VSM) verified that the nanoparticles owned good magnetic property. The grafted ?-cyclodextrin on the Fe3O4 nanoparticles contributed to as a modified electrode for detecting uric acid with cyclic voltammograms. Electrochemical results revealed that the new materials could exhibit excellent molecules recognition ability and show high electrochemical response. The new nanoparticles simultaneously had unique properties of magnetic nanoparticles and cyclodextrins through combining their individual distinct advantages.

263

Novel magnetic-fluorescent CS-Fe3O4@ZnS:Mn/ZnS (core/shell) nanoparticles: Preparation, characterization and damage to bovine serum albumin under UV irradiation  

International Nuclear Information System (INIS)

Novel magnetic-fluorescent nanoparticles (CS-Fe3O4@ZnS:Mn/ZnS) combined ZnS:Mn/ZnS semiconductor nanoparticles and Fe3O4 magnetic nanoparticles with chitosan (CS) matrix were prepared and characterized. Characterization results indicate that CS-Fe3O4@ZnS:Mn/ZnS (core/shell) nanoparticles show superparamagnetic and strong fluorescent properties. Introduction of ZnS shell significantly enhances the photoluminescence intensity by 3.5 times. The saturation magnetization of CS-Fe3O4@ZnS:Mn/ZnS nanoparticles was 14.85 emu g?1 at room temperature. The interaction and damage of CS-Fe3O4@ZnS:Mn/ZnS to bovine serum albumin (BSA) under UV irradiation was investigated by ultraviolet–visible and fluorescence spectra. The results show that electrostatic interaction is the major force for the binding processes of BSA to the surface of CS-Fe3O4@ZnS:Mn/ZnS. The damage of BSA is prone to happen in the presence of CS-Fe3O4@ZnS:Mn/ZnS under UV irradiation. CS-Fe3O4@ZnS:Mn/ZnS may be potential candidate for application as photosensitizers in photodynamic therapy, and fluorescence imaging and magnetic resonance imaging contrast agents for theranostics of cancer. - Highlights: • Novel magnetic-fluorescent CS-Fe3O4@ZnS:Mn/ZnS nanoparticles were synthesized. • CS-Fe3O4@ZnS:Mn/ZnS possesses superparamagnetic and bright fluorescent properties. • Introduction of ZnS shell significantly enhances the PL intensity by 3.5 times. • BSA molecule was effectively damaged by CS-Fe3O4@ZnS:Mn/ZnS under UV irradiation. • Magnetic-fluorescent nanoparticles would be potential agents for cancer treatment

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Co-encapsulation of magnetic Fe3O4 nanoparticles and doxorubicin into biodegradable PLGA nanocarriers for intratumoral drug delivery  

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Full Text Available Yanhui Jia1, Mei Yuan1, Huidong Yuan1, Xinglu Huang2, Xiang Sui1, Xuemei Cui1, Fangqiong Tang2, Jiang Peng1, Jiying Chen1, Shibi Lu1, Wenjing Xu1, Li Zhang1, Quanyi Guo11Institute of Orthopedics, General Hospital of the Chinese People's Liberation Army, Beijing, People's Republic of China; 2Laboratory of Controllable Preparation and Application of Nanomaterials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of ChinaAbstract: In this study, the authors constructed a novel PLGA [poly(D,L-lactic-co-glycolic acid]-based polymeric nanocarrier co-encapsulated with doxorubicin (DOX and magnetic Fe3O4 nanoparticles (MNPs using a single emulsion evaporation method. The DOX-MNPs showed high entrapment efficiency, and they supported a sustained and steady release of DOX. Moreover, the drug release was pH sensitive, with a faster release rate in an acidic environment than in a neutral environment. In vitro, the DOX-MNPs were easily internalized into murine Lewis lung carcinoma cells and they induced apoptosis. In vivo, the DOX-MNPs showed higher antitumor activity than free DOX solution. Furthermore, the antitumor activity of the DOX-MNPs was higher with than without an external magnetic field; they were also associated with smaller tumor volume and a lower metastases incidence rate. This work may provide a new modality for developing an effective drug delivery system.Keywords: antitumor activity, external magnetic field, intratumoral injection, apoptosis, Lewis lung carcinoma

Jia Y

2012-03-01

265

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

Science.gov (United States)

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 Fe(3)O(4) 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. PMID:22787394

Huang, Kai-Wen; Chieh, Jen-Jie; Horng, Herng-Er; Hong, Chin-Yih; Yang, Hong-Chang

2012-01-01

266

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

267

Highly sensitive and selective OFF-ON fluorescent sensor based on functionalized Fe3O4@SiO2 nanoparticles for detection of Zn2+ in acetonitrile media  

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The Fe3O4 nanoparticles [NPs] coated with silica nanoparticles were designed to produce magnetic core-shell Fe3O4@SiO2 NPs, which were modified with rhodamine B derivatives and defined as Fe3O4@SiO2-Rho NPs. The obtained Fe3O4@SiO2-Rho NPs served as a fluorescent OFF-ON nanosensor was utilized to detect Zn2+ selectively in acetonitrile medium. The Fe3O4@SiO2-Rho NPs exhibited selective "turn-on" type fluorescent enhancements and distinct color changes with Zn2+. The Fe3O4@SiO2-Rho NPs also showed a high capacity for removal of Zn2+ at room temperature. The removal efficiency toward Zn2+ was about 87.34%. In addition, the presence of magnetic Fe3O4 particles as core in Fe3O4@SiO2-Rho NPs could facilitate the magnetic separation of the Fe3O4@SiO2-Rho-Zn2+ from the solution.

Xu, Yaohui; Zhou, Yang; Ma, Wenhui; Wang, Shixing; Li, Shaoyuan

2013-07-01

268

Synthesis of Fe3O4@Y2O3:Eu3+ core-shell multifunctional nanoparticles and their magnetic and luminescence properties  

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A simple wet chemical route has been employed to synthesize multifunctional core-shell nanoparticles of Fe3O4@Y2O3:Eu3+ showing an interesting combination of magnetic and luminescent properties having potential for medical applications. The core-shell nanoparticles were synthesized in a two-step process wherein first step, the Fe3O4 nanoparticles were synthesized and subsequently they are coated with Y2O3:Eu3+. XRD and magnetization curves were successfully used to retrieve the particle size of Fe3O4 nanoparticles. Particle size (˜10 nm) extracted from XRD and magnetization curves have been found to be consistent with the measured size from AFM and TEM. Further, the XRD analysis reveals formation of pure cubic phases of magnetite as well as of Y2O3:Eu3+. It has been shown here that through simple chemistry it is possible to change the thickness of Y2O3:Eu3+ shell. From SEM and TEM studies, the size of core shell nanoparticles seen as ˜30 nm. In addition to bright red (612 nm) emission, these materials also show superparamagnetic behavior at room temperature. Emission intensity has been found to significantly increase with increase in annealing temperature. The synthesized materials have extensive for applications in the area of drug delivery and bio-imaging.

Gowd, Genekehal Siddaramana; Patra, Manoj Kumar; Mathew, Manoth; Shukla, Anuj; Songara, Sandhya; Vadera, Sampat Raj; Kumar, Narendra

2013-07-01

269

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

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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

270

The effects of magnetite (Fe3O4 nanoparticles on electroporation-induced inward currents in pituitary tumor (GH3 cells and in RAW 264.7 macrophages  

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Full Text Available Yen-Chin Liu1, Ping-Ching Wu2, Dar-Bin Shieh2–5, Sheng-Nan Wu3,6,71Department of Anesthesiology, 2Institute of Oral Medicine and Department of Stomatology, 3Department of Physiology, National Cheng Kung University Hospital, College of Medicine, 4Advanced Optoelectronic Technology Center, 5Center for Micro/Nano Science and Technology, National Cheng Kung University, 6Innovation Center for Advanced Medical Device Technology, National Cheng Kung University, 7Department of Anatomy and Cell Biology, National Cheng Kung University Medical College, Tainan, TaiwanAims: Fe3O4 nanoparticles (NPs have been known to provide a distinct image contrast effect for magnetic resonance imaging owing to their super paramagnetic properties on local magnetic fields. However, the possible effects of these NPs on membrane ion currents that concurrently induce local magnetic field perturbation remain unclear.Methods: We evaluated whether amine surface-modified Fe3O4 NPs have any effect on ion currents in pituitary tumor (GH3 cells via voltage clamp methods.Results: The addition of Fe3O4 NPs decreases the amplitude of membrane electroporation-induced currents (IMEP with a half-maximal inhibitory concentration at 45 µg/mL. Fe3O4 NPs at a concentration of 3 mg/mL produced a biphasic response in the amplitude of IMEP, ie, an initial decrease followed by a sustained increase. A similar effect was also noted in RAW 264.7 macrophages.Conclusion: The modulation of magnetic electroporation-induced currents by Fe3O4 NPs constitutes an important approach for cell tracking under various imaging modalities or facilitated drug delivery.Keywords: iron oxide, ion current, free radical

Liu YC

2012-03-01

271

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

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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

272

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

273

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

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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

274

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...

Khan, Farooq-ahmad; Su?ss-fink, Georg

2012-01-01

275

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

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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

276

Design of magnetic and fluorescent Mg-Al layered double hydroxides by introducing Fe3O4 nanoparticles and Eu3+ ions for intercalation of glycine  

International Nuclear Information System (INIS)

We describe a novel route for the preparation of magnetic and fluorescent magnesium-aluminum layered double hydroxides by introducing Fe3O4 nanoparticles and Eu3+ ions. From the powder X-ray diffraction results, it was found that the Fe3O4 nanoparticles were highly dispersed in the inner void of octahedral lattice, and the Eu3+ ions substituted for the Al3+ ions and entered into hydrotalcite lattice through isomorphous replacement. Moderate introduction of Fe3O4 nanoparticles and Eu3+ ions did not change the lamellar structure of magnesium-aluminum layered double hydroxides. Glycine can also be intercalated into this magnetic and fluorescent layered double hydroxides by ion-exchange method. After intercalation of glycine, the basal spacing of magnetic and fluorescent layered double hydroxides increased from 7.6 to 8.8 A, indicating that glycine was successfully intercalated into the interlayer space of layered double hydroxides. Magnetic measurements reveal that these novel layered double hydroxides possess paramagnetic property at room temperature, and the emission and excitation spectra indicate the layered double hydroxides exhibit fluorescent property.

277

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

278

Daunorubicin-loaded magnetic nanoparticles of Fe3O4 overcome multidrug resistance and induce apoptosis of K562-n/VCR cells in vivo  

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Full Text Available Bao-an Chen1, Bin-bin Lai1, Jian Cheng1, Guo-hua Xia1, Feng Gao1, Wen-lin Xu2, Jia-hua Ding1, Chong Gao1, Xin-chen Sun3, Cui-rong Xu1, Wen-ji Chen1, Ning-na Chen1, Li-jie Liu4, Xiao-mao Li5, Xue-mei Wang61Department of Hematology, 3Department of Oncology, the Affiliated Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Hematology, the Affiliated People’s Hospital, Jiangsu University, Zhenjiang, People’s Republic of China; 4Institution of Physiology, 6State Key Lab of Bioelectronics (Chien-shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of China; 5Department of Physics, University of Saarland, Saarbruechen, GermanyAbstract: Multidrug resistance (MDR is a major obstacle to cancer chemotherapy. We evaluated the effect of daunorubicin (DNR-loaded magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4 on K562-n/VCR cells in vivo. K562-n and its MDR counterpart K562-n/VCR cell were inoculated into nude mice subcutaneously. The mice were randomly divided into four groups: group A received normal saline, group B received DNR, group C received MNPs-Fe3O4, and group D received DNR-loaded MNPs-Fe3O4. For K562-n/VCR tumor, the weight was markedly lower in group D than that in groups A, B, and C. The transcriptions of Mdr-1 and Bcl-2 gene were significantly lower in group D than those in groups A, B, and C. The expression of Bcl-2 was lower in group D than those in groups A, B, and C, but there was no difference in the expression of P-glycoprotein. The transcriptions and expressions of Bax and caspase-3 in group D were increased significantly when compared with groups A, B, and C. In conclusion, DNR-loaded MNPs-Fe3O4 can overcome MDR in vivo.Keywords: multidrug-resistance reversal, leukemia, magnetic nanoparticles of Fe3O4, in vivo

Bao-an Chen

2009-09-01

279

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

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Full Text Available Jian Cheng1*, Weiwei Wu1*, Bao-an Chen1, Feng Gao1, Wenlin Xu2, Chong Gao1, Jiahua Ding1, Yunyu Sun1, Huihui Song1, Wen Bao1, Xinchen Sun3, Cuirong Xu1, Wenji Chen1, Ningna Chen1, Lijie Liu4, Guohua Xia1, Xiaomao Li5, Xuemei Wang61Department of Hematology, 3Department of Oncology, The Afiliated Zhongda Hospital, Southeast University, Nanjing, People’s Republic of China; 2Department of Hematology, The First People’s Hospital of Zhengjiang, Zhenjiang, People’s Republic of China; 4Institution of Physiology, 6State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of China; 5Department of Physics, University of Saarland, Saarbruechen, Germany; *These authors have contributed equally to this workAbstract: 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 performed to examine the mRNA and protein levels of mdr1, respectively. The results showed that the combination of MNPs-Fe3O4 and BrTet with effective concentrations significantly increased cytotoxicity against MDR cell line K562/A02. Both BrTet and MNPs-Fe3O4 increased the intracellular DNR accumulation in the K562/A02 cell line, and downregulated the level of mdr1 gene and expression of P-glycoprotein. Furthermore, the combination did not have significant cytotoxicity in PMBCs. We propose that MNPs-Fe3O4 conjugated with DNR and BrTet probably have synergetic effects on MDR reversal.Keywords: magnetic nanoparticles of Fe3O4, 5-bromotetrandrine, multidrug resistance K562/A02

Jian Cheng

2009-09-01

280

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

 
 
 
 
281

A highly selective photoelectrochemical biosensor for uric acid based on core-shell Fe3O4@C nanoparticle and molecularly imprinted TiO2.  

Science.gov (United States)

Combining the surface modification and molecular imprinting technique, a novel photoelectrochemical sensing platform with excellent photochemical catalysis and molecular recognition capabilities was established for the detection of uric acid based on the magnetic immobilization of Fe3O4@C nanoparticles onto magnetic glassy carbon electrode (MGCE) and modification of molecularly imprinted TiO2 film on Fe3O4@C. The developed biosensor was highly sensitive to uric acid in solutions, with a linear range from 0.3 to 34µM and a limit of detection of 0.02?M. Furthermore, the biosensor exhibited outstanding selectivity while used in coexisting systems containing various interferents with high concentration. The practical application of the biosensor was also realized for the selective detection of uric acid in spiked samples. The study made a successful attempt in the development of highly selective and sensitive photoelectrochemical biosensor for urine monitoring. PMID:25461147

Zhang, Chunjing; Si, Shihui; Yang, Zhengpeng

2014-10-16

282

Carbon-wrapped Fe3O4 nanoparticle films grown on nickel foam as binder-free anodes for high-rate and long-life lithium storage.  

Science.gov (United States)

Carbon-wrapped Fe3O4 nanoparticle films on nickel foam were simply prepared by a hydrothermal synthesis with sucrose as a precursor of subsequent carbonization. The as-prepared samples were directly used as binder-free anodes for lithium-ion batteries which exhibited enhanced rate performance and excellent cyclability. A reversible capacity of 543 mA h g(-1) was delivered at a current density as high as 10 C after more than 2000 cycles. The superior electrochemical performance can be attributed to the formation of a thin carbon layer which constructs a 3D network structure enwrapping the nanosized Fe3O4 particles. Such an architecture can facilitate the electron transfer and accommodate the volume change of the active materials during discharge/charge cycling. PMID:24320600

Li, Dan; Li, Xiuwan; Wang, Suiyan; Zheng, Yunxian; Qiao, Li; He, Deyan

2014-01-01

283

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

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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 prese...

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

2013-01-01

284

Synthesis and Properties of Fe3O4-Activated Carbon Magnetic Nanoparticles for Removal of Aniline from Aqueous Solution: Equilibrium, Kinetic and Thermodynamic Studies  

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Full Text Available In this study, powder activated carbon (PAC and magnetic nanoparticles of iron (III oxide were used for synthesis of Fe3O4-activated carbon magnetic nanoparticles (AC-Fe3O4 MNPs as an adsorbent for the removal of aniline. The characteristics of adsorbent were evaluated by SEM, TEM, XRD and BET. Also, the impact of different parameters such as pH, contact time, adsorbent dosage, aniline initials concentration and solution temperature were studied. The experimental data investigated by Langmuir and Freundlich adsorption isotherms and two models kinetically of pseudo first-order and pseudo second-order. The results indicated that the adsorption followed Langmuir and pseudo second-order models with correlation r2?>?0.98 and r2?>?0.99, respectively. The equilibrium time was obtained after 5 h. According to Langmuir model, the maximum adsorption capacity was 90.91 mg/g at pH?=?6, and 20°C. The thermodynamic parameters indicated that adsorption of aniline on magnetic activated carbon was exothermic and spontaneous. This synthesized AC-Fe3O4 MNPs due to have advantages such as easy and rapid separation from solution could be applied as an adsorbent effective for removal of pollutants such as aniline from water and wastewater

Babak Kakavandi

2013-02-01

285

Characterization of Fe3O4/SiO2/Gd2O(CO3)2 core/shell/shell nanoparticles as T1 and T2 dual mode MRI contrast agent.  

Science.gov (United States)

Core/shell/shell structured Fe3O4/SiO2/Gd2O(CO3)2 nanoparticles were successfully synthesized. Their properties as a new type of T1-T2 dual model contrast agent for magnetic resonance imaging were investigated. Due to the introduce of a separating SiO2 layer, the magnetic coupling between Gd2O(CO3)2 and Fe3O4 could be modulated by the thickness of SiO2 layer and produce appropriate T1 and T2 signal. Additionally, the existence of Gd(3+) enhances the transverse relaxivity of Fe3O4 possibly because of the magnetic coupling between Gd(3+) and Fe3O4. The Fe3O4/SiO2/Gd2O(CO3)2 nanoparticles exhibit good biocompatibility, showing great potential for biomedical applications. PMID:25281156

Yang, Meicheng; Gao, Lipeng; Liu, Kai; Luo, Chunhua; Wang, Yiting; Yu, Lei; Peng, Hui; Zhang, Wen

2015-01-01

286

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

287

Effects of core/shell structure on magnetic induction heating promotion in Fe3O4/?-Fe2O3 magnetic nanoparticles for hyperthermia  

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Fe3O4/?-Fe2O3 core-shell magnetic nanoparticles have demonstrated superior heating efficiency by applying the alternating magnetic field. The magnetic induction heating properties of core-shell magnetic nanoparticles were analyzed by the rate-dependent hysteresis model, taken into account the magnetic anisotropies and actual size distribution of particles. The analyzed results have disclosed the significance of magnetic anisotropies and shell-thickness to the promotion of magnetic induction heating performance. Further experiments about the cancer cells with uptake of these core-shell magnetic nanoparticles conjugated biocompatible cationic liposomes have achieved in vitro intracellular magnetically induced hyperthermia under a weak alternating magnetic field.

Lee, Shih-Chi; Fu, Chao-Ming; Chang, Fu-Hsiung

2013-10-01

288

Novel electrochemical sensing platform based on magnetic field-induced self-assembly of Fe3O4@Polyaniline nanoparticles for clinical detection of creatinine.  

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A novel electrochemical sensing platform based on magnetic field-induced self-assembly of Fe3O4@Polyaniline nanoparticles (Fe3O4@PANI NPs) has been for the first time fabricated for the sensitive detection of creatinine in biological fluids. The template molecule, creatinine, was self-assembled on the surface of Fe3O4@PANI NPs together with the functional monomer aniline by the formation of N-H hydrogen bonds. After pre-assembled, through the magnetic-induction of the magnetic glassy carbon electrode (MGCE), the ordered structure of molecularly imprinted polymers (MIPs) were established by the electropolymerization and assembled on the surface of MGCE with the help of magnetic fields by a simple one-step approach. The structural controllability of the MIPs film established by magnetic field-induced self-assembly was further studied. The stable and hydrophilic Fe3O4@PANI can not only provide available functionalized sites with which the template molecule creatinine can form hydrogen bond by the abundant amino groups in PANI matrix, but also afford a promoting pathway for electron transfer. The as-prepared molecularly imprinted electrochemical sensor (MIES) shows good stability and reproducibility for the determination of creatinine with the detection limit reached 0.35 nmol L(-1) (S/N=3). In addition, the highly sensitive and selective MIES has been successfully used for the clinical determination of creatinine in human plasma and urine samples. The average recoveries were 90.8-104.9% with RSD lower than 2.7%. PMID:24487254

Wen, Tingting; Zhu, Wanying; Xue, Cheng; Wu, Jinhua; Han, Qing; Wang, Xi; Zhou, Xuemin; Jiang, Huijun

2014-06-15

289

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

290

Synthesis and diameter control of vertically-aligned carbon nanotube growth from Langmuir-Blodgett films deposited Fe3O4@SiO2 core-shell nanoparticles  

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We synthesized Fe3O4 nanoparticles (NPs) and Fe3O4@SiO2 core-shell NPs. Vertically-aligned carbon nanotubes (VA-CNTs) were grown from Fe3O4 NP monolayer and Fe3O4@SiO2 core-shell NP monolayer, respectively, by thermal chemical vapor deposition (CVD). The monolayer was prepared on SiO2/Si substrate by Langmuir-Blodgett (LB) technique. Fe3O4 NP monolayer was used as catalyst for CNT growth, and core-shell NP monolayer was used as catalyst for CNT growth, too. We found that Fe3O4 NP covered with SiO2 shell was moved from the center to the surface of core-shell NP during pre-thermal process at thermal CVD. The CNT carpet height tended to increase with the increasing thermal annealing time and decreasing shell thickness. And the average diameter of CNTs grown from core-shell LB film was smaller than that of CNTs grown from Fe3O4 LB film, and average diameter of CNTs almost conformed to Fe3O4 core size with SiO2 shell.

Ohashi, Masaaki; Sugawara, Takehiro; Kawasaki, Kohei; Kushida, Masahito

2014-02-01

291

Transverse Susceptibility as a Biosensor for Detection of Au-Fe3O4 Nanoparticle-Embedded Human Embryonic Kidney Cells  

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Full Text Available We demonstrate the possibility of using a radio-frequency transverse susceptibility (TS technique based on a sensitive self-resonant tunnel-diode oscillator as a biosensor for detection of cancer cells that have taken up magnetic nanoparticles. This technique can detect changes in frequency on the order of 10 Hz in 10 MHz. Therefore, a small sample of cells that have taken up nanoparticles when placed inside the sample space of the TS probe can yield a signal characteristic of the magnetic nanoparticles. As a proof of the concept, Fe3O4 nanoparticles coated with Au (mean size ~60 nm were synthesized using a micellar method and these nanoparticles were introduced to the medium at different concentrations of 0.05, 0.1, 0.5, and 1 mg/mL buffer, where they were taken up by human embryonic kidney (HEK cells via phagocytosis. While the highest concentration of Au-Fe3O4 nanoparticles (1 mg/mL was found to give the strongest TS signal, it is notable that the TS signal of the nanoparticles could still be detected at concentrations as low as 0.1 mg/mL.

Pritish Mukherjee

2013-07-01

292

Study of magnetic and structural and optical properties of Zn doped Fe3O4 nanoparticles synthesized by co-precipitation method for biomedical application  

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Abstract Objective(s): This paper describes synthesizing of magnetic nanocomposite with co-precipitation method. Materials and Methods: Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125) were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe 3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetom...

Zahra Rezay Marand; Mitra Helmi Rashid Farimani; Nasser Shahtahmasebi

2014-01-01

293

An Ultrasensitive Electrochemiluminescence Immunoassay for Carbohydrate Antigen 19-9 in Serum Based on Antibody Labeled Fe3O4 Nanoparticles as Capture Probes and Graphene/CdTe Quantum Dot Bionanoconjugates as Signal Amplifiers  

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The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran–Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9’s first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G),...

Ning Gan; Jing Zhou; Ping Xiong; Tianhua Li; Shan Jiang; Yuting Cao; Qianli Jiang

2013-01-01

294

In situ preparation of magnetic Fe3O4 nanoparticles inside nanoporous poly(L-glutamic acid)/chitosan microcapsules for drug delivery.  

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The magnetic polymer microcapsules, as a promising environmental stimuli-responsive delivery vehicle, have been increasingly exploited to tackle the problem of remotely navigated delivery. This study presented a novel design and fabrication of magnetic poly(L-glutamic acid)/chitosan (PGA/CS) microcapsules. Magnetic Fe3O4 nanoparticles were in situ synthesized inside nanoporous PGA/CS microcapsules and resultant magnetic PGA/CS microcapsules were characterized. Mitoxantrone (MTX), an antineoplastic drug, was chosen as a water-soluble model drug to research the loading and release properties of the microcapsules. The results showed the carboxylate groups of PGA within polyelectrolyte walls could be used as binding sites for the absorption of iron ions and reaction sites for the synthesis of magnetic nanoparticles. Magnetic PGA/CS microcapsules were dissected using a dual-beam scanning electron microscope/focused ion beam (SEM/FIB) for morphological and microstructural examination. It was found that Fe3O4 nanoparticles with size of about 10nm were homogeneously dispersed in the polymer matrix and adhered to the pore walls of the microcapsules. Increasing the concentration of iron ions led to an increasing loading content of Fe3O4 nanoparticles and an increase in the resultant magnetization. The magnetic PGA/CS microcapsules could be easily manipulated by an external magnetic field. The MTX loading capacity depended on loading time and MTX concentration. The high loading could be ascribed to spontaneous deposition of MTX induced by electrostatic interaction. The microcapsules exhibited sustained release behavior. The MTX release from microcapsules could be best described using Korsmeyer-Peppas and Baker-Lonsdale models, indicating the diffusion mechanism of drug release from both PGA/CS microcapsules and magnetic PGA/CS microcapsules. Therefore, the novel magnetic PGA/CS microcapsules are expected to find application in drug delivery systems because of the properties of magnetic sensitivity, high drug loading and sustained release. PMID:24121073

Yan, Shifeng; Zhang, Xin; Sun, Yuanyuan; Wang, Taotao; Chen, Xuesi; Yin, Jingbo

2014-01-01

295

Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and MDR1 shRNA expression vector in leukemia cells  

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Full Text Available Bao-an Chen1, Pei-pei Mao1, Jian Cheng1, Feng Gao1, Guo-hua Xia1, Wen-lin Xu2, Hui-lin Shen2, Jia-hua Ding1, Chong Gao1, Qian Sun1, Wen-ji Chen1, Ning-na Chen1, Li-jie Liu3, Xiao-mao Li4, Xue-mei Wang51Department of Hematology, The Affiliated Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, People’s Republic of China; 3Institution of Physiology, Southeast University, Nanjing, People’s Republic of China; 4Department of Physics, University of Saarland, Saarbruecken, Germany; 5State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, People’s Republic of ChinaAbstract: In many instances, multidrug resistance (MDR is mediated by increasing the expression at the cell surface of the MDR1 gene product, P-glycoprotein (P-gp, a 170-kD energy-dependent efflux pump. The aim of this study was to investigate the potential benefit of combination therapy with magnetic Fe3O4 nanoparticle [MNP (Fe3O4] and MDR1 shRNA expression vector in K562/A02 cells. For stable reversal of “classical” MDR by short hairpin RNA (shRNA aiming directly at the target sequence (3491–3509, 1539–1557, and 3103–3121 nucleotide of MDR1 mRNA. PGC silencer-U6-neo-GFP-shRNA/MDR1 called PGY1–1, PGY1–2, and PGY1–3 were constructed and transfected into K562/A02 cells by lipofectamine 2000. After transfected and incubated with or without MNP (Fe3O4 for 48 hours, the transcription of MDR1 mRNA and the expression of P-gp were detected by quantitative real-time PCR and Western-blot assay respectively. Meanwhile intracellular concentration of DNR in K562/A02 cells was detected by flow cytometry (FCM. PGC silencer-U6-neo-GFP-shRNA/MDR1 was successfully constructed, which was confirmed by sequencing and PGY1–2 had the greatest MDR1 gene inhibitory ratio. Analysis of the reversal ratio of MDR, the concentration of daunorubicin (DNR and the transcription of MDR1 gene and expression of P-gp in K562/A02 showed that combination of DNR with either MNP (Fe3O4 or PGY1–2 exerted a potent cytotoxic effect on K562/A02 cells, while combination of MNP (Fe3O4 and PGY1–2 could synergistically reverse multidrug resistance. Thus our in vitro data strongly suggested that a combination of MNP (Fe3O4 and shRNA expression vector might be a more sufficient and less toxic anti-MDR method on leukemia. Keywords: K562/A02 cell line, multidrug resistance, magnetic nanoparticle of Fe3O4, recombinant plasmid vector PGY1–2

Bao-an Chen

2010-06-01

296

Study of magnetic and structural and optical properties of Zn doped Fe3O4 nanoparticles synthesized by co-precipitation method for biomedical application  

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Full Text Available Abstract Objective(s: This paper describes synthesizing of magnetic nanocomposite with co-precipitation method. Materials and Methods: Magnetic ZnxFe3-xO4 nanoparticles with 0-14% zinc doping (x=0, 0.025, 0.05, 0.075, 0.1 and 0.125 were successfully synthesized by co-precipitation method. The prepared zinc-doped Fe 3O4 nanoparticles were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR, vibrating sample magnetometer (VSM and UV-Vis spectroscopy. Results: results obtained from X-ray diffraction pattern have revealed the formation of single phase nanoparticles with cubic inverse spinal structures which size varies from 11.13 to 12.81 nm. The prepared nanoparticles have also possessed superparamagnetic properties at room temperature and high level of saturation magnetization with the maximum level of 74.60 emu/g for x=0.075. Ms changing in pure magnetite nanoparticles after impurities addition were explained based on two factors of “particles size” and “exchange interactions”. Optical studies results revealed that band gaps in all Zn-doped NPs are higher than pure Fe 3O4. As doping percent increases, band gap value decreases from 1.26 eV to 0.43 eV. Conclusion: these magnetic nanocomposite structures since having superparamagnetic property offer a high potential for biosensing and biomedical application.

Zahra Rezay Marand

2014-09-01

297

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

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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

298

Giant Barkhausen jumps in exchange biased bulk nanocomposites sinterd fom core-shell Fe3O4-CoO nanoparticles  

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The magnetic behavior of spark plasma sintered Fe3O4-CoO nanoparticles is studied. The samples sintered at 500°C exhibit density over 90% and average magnetite grain size about 100 nm. When the nanocomposite is field cooled below the Néel temperature (TN=291 K for CoO), hysteresis loops shows the expected shift with an exchange field of 80 mT at 100 K that drops down to zero approaching TN. The coercivity at 100 K reaches 0.4 T, ten times larger than nanostructured magnetite prepared in the...

Gaudisson, Thomas; Ammar, Souad; Lobue, Martino; Mazaleyrat, Frederic

2013-01-01

299

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)

300

Synthesis and ageing effect in FeO nanoparticles: Transformation to core-shell FeO/Fe3O4 and their magnetic characterization  

International Nuclear Information System (INIS)

Graphical abstract: Display Omitted Highlights: ? Ageing effect in FeO nanoparticles and their transformation into core-shell FeO/Fe3O4 nanoparticles with enhanced chemical stability. ? The magnetic hystersis loop exhibit a set of interesting and unique features arising from the strong interfacial exchange coupling between the AFM core (FeO) and FiM (Fe3O4) shell viz., exchange bias and coercivity enhancement. - Abstract: This paper reports the magnetic properties of partially oxidized FeO nanoparticles (NPs) prepared using thermal decomposition of iron acetylacetonate at high temperature. X-ray diffraction (XRD) analysis confirmed that the resulting NPs comprise a mixture of wuestite and magnetite phases, which are subsequently confirmed using high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) pattern. Magnetic properties were investigated using vibrating sample magnetometer (VSM), which exhibit superparamagnetic (SPM) behavior at room temperature. Alternatively, below 200 K, a large exchange bias field has been observed in field cooled mode whose magnitude increases with the decrease in measuring temperature attaining a maximum value of ?2.3 kOe at 2 K accompanied by coercivity enhancement (?3.4 kOe) and high field of irreversibility (>50 kOe). The results are discussed taking into account the role of interface exchange coupling on the macroscopic magnetic properon the macroscopic magnetic properties of the nanoparticles.

 
 
 
 
301

Fe3O4-ZrO2 nanoparticles magnetic solid phase extraction coupled with flame atomic absorption spectrometry for chromium(III) speciation in environmental and biological samples  

International Nuclear Information System (INIS)

A new method for Cr(III) speciation in seven kinds of environmental and biological samples by Fe3O4-ZrO2 nanoparticles magnetic solid phase extraction (MSPE) and flame atomic absorption spectrometry (FAAS) has been developed. Fe3O4-ZrO2 nanoparticles were simply prepared by sol-gel method, and the adsorptive behaviors of Cr(III) and Cr(VI) on Fe3O4-ZrO2 nanoparticles were assessed. At pH 8.0-9.0, Fe3O4-ZrO2 nanoparticles were selective towards Cr(III) but hardly Cr(VI). The retained Cr(III) was subsequently eluted with 3.0 mL of 0.5 mol L-1 HNO3 followed by magnetic decantation. Total chromium was determined after reduction of Cr(VI) to Cr(III) by ascorbic acid. Various parameters affecting Fe3O4-ZrO2 nanoparticles MSPE were optimized systematically. Under the optimum conditions, the adsorption capacity of Fe3O4-ZrO2 nanoparticles for Cr(III) is 24.5 mg g-1. With an enrichment factor (EF) of 25, detection limit of Cr(III) was 0.69 ng mL-1, and the proposed method has been successfully applied for Cr(III) speciation in seven kinds of environmental and biological samples with satisfactory results.

302

Magnetic, optical and relaxometric properties of organically coated gold–magnetite (Au–Fe3O4) hybrid nanoparticles for potential use in biomedical applications  

International Nuclear Information System (INIS)

We present the magnetic, optical and relaxometric properties of multifunctional Au–Fe3O4 hybrid nanoparticles (HNPs), as possible novel contrast agents (CAs) for magnetic resonance imaging (MRI). The HNPs have been synthesized by wet chemical methods in heterodimer and core–shell geometries and capped with oleylamine. Structural characterization of the samples have been made by X-ray diffraction and transmission electron microscopy, while magnetic properties have been investigated by means of Superconducting Quantum Interference Device-SQUID magnetometry experiments. As required for MRI applications using negative CAs, the samples resulted superparamagnetic at room temperature and well above their blocking temperatures. Optical properties have been investigated by analyzing the optical absorbtion spectra collected in UV–visible region. Relaxometric measurements have been performed on organic suspensions of HNPs and Nuclear Magnetic Resonance (NMR) dispersion curves have been obtained by measuring the longitudinal 1/T1 and transverse 1/T2 relaxation rates of solvent protons in the range 10 kHz/300 MHz at room temperature. NMR relaxivities r1 and r2 have been compared with ENDOREM®, one of the commercial superparamagnetic iron oxide based MRI contrast agents. MRI contrast enhancement efficiencies have been investigated also by examining T2-weighted MR images of suspensions. Thighted MR images of suspensions. The experimental results suggest that the nanoparticles' suspensions are good candidates as negative CAs. - Highlights: ? Au–Fe3O4 superparamagnetic Hybrid NanoPrticles (HNPs) enhance contrast in MRI. ? HNPs are expected to have optical activities through observed SPR phenomena. ? HNPs have relatively high magnetic anisotropy originating from Au/Fe3O4 interface. ? Magnetic dipolar interactions have been observed between particles in powders.

303

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

304

Design and construction of polymerized-chitosan coated Fe3O4 magnetic nanoparticles and its application for hydrophobic drug delivery.  

Science.gov (United States)

In this study, a novel hydrogel, chitosan (CS) crosslinked carboxymethyl-?-cyclodextrin (CM-?-CD) polymer modified Fe3O4 magnetic nanoparticles was synthesized for delivering hydrophobic anticancer drug 5-fluorouracil (CS-CDpoly-MNPs). Carboxymethyl-?-cyclodextrin being grafted on the Fe3O4 nanoparticles (CDpoly-MNPs) contributed to an enhancement of adsorption capacities because of the inclusion abilities of its hydrophobic cavity with insoluble anticancer drugs through host-guest interactions. Experimental results indicated that the amounts of crosslinking agent and bonding times played a crucial role in determining morphology features of the hybrid nanocarriers. The nanocarriers exhibited a high loading efficiency (44.7±1.8%) with a high saturation magnetization of 43.8emu/g. UV-Vis spectroscopy results showed that anticancer drug 5-fluorouracil (5-Fu) could be successfully included into the cavities of the covalently linked CDpoly-MNPs. Moreover, the free carboxymethyl groups could enhance the bonding interactions between the covalently linked CDpoly-MNPs and anticancer drugs. In vitro release studies revealed that the release behaviors of CS-CDpoly-MNPs carriers were pH dependent and demonstrated a swelling and diffusion controlled release. A lower pH value led to swelling effect and electrostatic repulsion contributing to the protonation amine impact of NH3(+), and thus resulted in a higher release rate of 5-Fu. The mechanism of 5-Fu encapsulated into the magnetic chitosan nanoparticles was tentatively proposed. PMID:25579950

Ding, Yongling; Shen, Shirley Z; Sun, Huadong; Sun, Kangning; Liu, Futian; Qi, Yushi; Yan, Jun

2015-03-01

305

Peroxidase-like activity of Fe3O4@carbon nanoparticles enhances ascorbic acid-induced oxidative stress and selective damage to PC-3 prostate cancer cells.  

Science.gov (United States)

Ascorbic acid (AA) is capable of inhibiting cancer cell growth by perturbing the normal redox state of cells and causing toxic effects through the generation of abundant reactive-oxygen species (ROS). However, the clinical utility of AA at a tolerable dosage is plagued by a relatively low in vivo efficacy. This study describes the development of a peroxidase-like composite nanoparticle for use in an AA-mediated therapeutic strategy. On the basis of a high-throughput, one-pot solvothermal approach, Fe3O4@C nanoparticles (NPs) were synthesized and then modified with folic acid (FA) on the surface. Particular focus is concentrated on the assessment of peroxidase-like catalytic activity by a chromogenic reaction in the presence of H2O2. The carbon shell of Fe3O4@C NPs contains partially graphitized carbon and thus facilitates electron transfer in the catalytic decomposition of H2O2, leading to the production of highly reactive hydroxyl radicals. Along with magnetic responsiveness and receptor-binding specificity, the intrinsic peroxidase-like catalytic activity of Fe3O4@C-FA NPs pronouncedly promotes AA-induced oxidative stress in cancer cells and optimizes the ROS-mediated antineoplastic efficacy of exogenous AA. In vitro experiments using human prostate cancer PC-3 cells demonstrate that Fe3O4@C-FA NPs serve as a peroxidase mimic to create hydroxyl radicals from endogenous H2O2 that is yielded in response to exogenous AA via an oxidative stress process. The usage of a dual agent leads to the enhanced cytotoxicity of PC-3 cells, and, because of the synergistic effect of NPs, the administrated dosage of AA is reduced markedly. However, because normal cells (HEK 293T cells) appear to have a higher capacity to cope with additionally generated ROS than cancer cells, the NP-AA combination shows little damage in this case, proving that selective killing of cancer cells could be achieved owing to preferential accumulation of ROS in cancer cells. A possible ROS-mediated mechanism is discussed to elucidate the pharmaceutical profile of the NP-AA agent. In general, this foundational study reveals that the peroxidase-like nanomaterials are applicable for modulating oxidative stress for the selective treatment of cancer cells by generating a high level of endogenous ROS. PMID:24199694

An, Qiao; Sun, Chuanyu; Li, Dian; Xu, Ke; Guo, Jia; Wang, Changchun

2013-12-26

306

56Co-labelled radioactive Fe3O4 nanoparticles for in vitro uptake studies on Balb/3T3 and Caco-2 cell lines  

International Nuclear Information System (INIS)

Magnetite nanoparticles (Fe3O4 NPs) are manufactured nanomaterials increasingly used in healthcare for different medical applications ranging from diagnosis to therapy. This study deals with the irradiation of Fe3O4 NPs with a proton beam in order to produce 56Co as radiolabel and also with the possible use of nuclear techniques for the quantification of Fe3O4 NPs in biological systems. Particular attention has been focused on the size distribution (in the range of 100 nm) and the surface charge of the NPs characterizing them before and after the irradiation process in order to verify if these essential properties would be preserved during irradiation. Moreover, X-ray diffraction studies have been performed on radioactive and non-radioactive NPs, to assess if major changes in NPs structure might occur due to thermal and/or radiation effects. The radiation emitted from the radiolabels has been used to quantify the cellular uptake of the NPs in in vitro studies. As for the biological applications two cell lines have been selected: immortalized mouse fibroblast cell line (Balb/3T3) and human epithelial colorectal adenocarcinoma cell line (Caco-2). The cell uptake has been quantified by radioactivity measurements of the 56Co radioisotope performed with high resolution ?-ray spectrometry equipment. This study has showed that, under well-established irradiation conditions, Fe33O4 NPs do not undergo significant structural modifications and thus the obtained results are in line with the uptake studies carried out with the same non-radioactive nanomaterials (NMs). Therefore, the radiolabelling method can be fruitfully applied to uptake studies because of the low-level exposure where higher sensitivity is required.

307

Origin of the large dispersion of magnetic properties in nanostructured oxides: FexO/Fe3O4 nanoparticles as a case study.  

Science.gov (United States)

The intimate relationship between stoichiometry and physicochemical properties in transition-metal oxides makes them appealing as tunable materials. These features become exacerbated when dealing with nanostructures. However, due to the complexity of nanoscale materials, establishing a distinct relationship between structure-morphology and functionalities is often complicated. In this regard, in the FexO/Fe3O4 system a largely unexplained broad dispersion of magnetic properties has been observed. Here we show, thanks to a comprehensive multi-technique approach, a clear correlation between the magneto-structural properties in large (45 nm) and small (9 nm) FexO/Fe3O4 core/shell nanoparticles that can explain the spread of magnetic behaviors. The results reveal that while the FexO core in the large nanoparticles is antiferromagnetic and has bulk-like stoichiometry and unit-cell parameters, the FexO core in the small particles is highly non-stoichiometric and strained, displaying no significant antiferromagnetism. These results highlight the importance of ample characterization to fully understand the properties of nanostructured metal oxides. PMID:25600147

Estrader, Marta; López-Ortega, Alberto; Golosovsky, Igor V; Estradé, Sònia; Roca, Alejandro G; Salazar-Alvarez, German; López-Conesa, Lluís; Tobia, Dina; Winkler, Elin; Ardisson, José D; Macedo, Waldemar A A; Morphis, Andreas; Vasilakaki, Marianna; Trohidou, Kalliopi N; Gukasov, Arsen; Mirebeau, Isabelle; Makarova, O L; Zysler, Roberto D; Peiró, Francesca; Baró, Maria Dolors; Bergström, Lennart; Nogués, Josep

2015-02-01

308

Magnetically assisted solid phase extraction using Fe3O4 nanoparticles combined with enhanced spectrofluorimetric detection for aflatoxin M1 determination in milk samples.  

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A novel, facile and inexpensive solid phase extraction (SPE) method using ethylene glycol bis-mercaptoacetate modified 3-(trimethoxysilyl)-1-propanethiol grafted Fe(3)O(4) nanoparticles coupled with spectrofluorimetric detection was proposed for determination of aflatoxin M1 (AFM1) in liquid milk samples. The method uses the advantage fluorescence enhancement by ?-cyclodexterin complexation of AFM1 in 12% (v/v) acetonitrile-water and the remarkable properties of Fe(3)O(4) nanoparticles namely high surface area and strong magnetization were utilized to achieve high enrichment factor (57) and satisfactory extraction recoveries (91-102%) using only 100 mg of magnetic adsorbent. Furthermore, fast separation time of about 15 min avoids many time-consuming column-passing procedures of conventional SPE. The main factors affecting extraction efficiency including pH value, desorption conditions, extraction/desorption time, sample volume, and adsorbent amount were evaluated and optimized. Under the optimal conditions, a wide linear range of 0.04-8 ng mL(-1) with a low detection limit of 0.015 ng mL(-1) was obtained. The developed method was applied for extraction and preconcentration of AFM1 in three commercially available milk samples and the results were compared with the official AOAC method. PMID:25127653

Taherimaslak, Zohreh; Amoli-Diva, Mitra; Allahyary, Mehdi; Pourghazi, Kamyar

2014-09-01

309

Exchange-coupled fct-FePd/?-Fe nanocomposite magnets converted from Pd/Fe3O4 core/shell nanoparticles.  

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We report the controlled synthesis of exchange-coupled face-centered tetragonal (fct) FePd/?-Fe nanocomposite magnets with variable Fe concentration. The composite was converted from Pd/Fe3O4 core/shell nanoparticles through a high-temperature annealing process in a reducing atmosphere. The shell thickness of core/shell Pd/Fe3O4 nanoparticles could be readily tuned, and subsequently the concentration of Fe in nanocomposite magnets was controlled. Upon annealing reduction, the hard magnetic fct-FePd phase was formed by the interdiffusion between reduced ?-Fe and face-centered cubic (fcc) Pd, whereas the excessive ?-Fe remained around the fct-FePd grains, realizing exchange coupling between the soft magnetic ?-Fe and hard magnetic fct-FePd phases. Magnetic measurements showed variation in the magnetic properties of the nanocomposite magnets with different compositions, indicating distinct exchange coupling at the interfaces. The coercivity of the exchange-coupled nanocomposites could be tuned from 0.7 to 2.8?kOe and the saturation magnetization could be controlled from 93 to 160?emu?g(-1). This work provides a bottom-up approach using exchange-coupled nanocomposites for engineering advanced permanent magnets with controllable magnetic properties. PMID:25255788

Liu, Fei; Dong, Yunhe; Yang, Wenlong; Yu, Jing; Xu, Zhichuan; Hou, Yanglong

2014-11-10

310

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

311

Magnetic BaFe12O19 nanofiber filter for effective separation of Fe3O4 nanoparticles and removal of arsenic  

International Nuclear Information System (INIS)

Magnetic nanoparticles are promising in applications where magnetic separation is intended, although material losses via leaching mechanisms are often inevitable. Magnetic separations with widely available permanent magnets can effectively trap particles, leading to a complete removal of used or waste particles. In this report, we first demonstrate the synthesis of the thinnest (112.7 ± 16.4 nm) and most magnetic (71.96 emu g?1) barium hexaferrite (BaFe12O19, BHF—fridge magnet) via an organic solvent-free electrospinning procedure. When the fibers are then packed into a column, they clearly remove 12 nm magnetite (Fe3O4) nanoparticles quantitatively. The same BHF cartridge also removes more than 99.9 % As-treated magnetite nanoparticles at capacities up to 70 times of its weight. As a result, one liter of 150 ?g L?1 As-contaminated water can be purified rapidly at a material cost of less than 2 US cents

312

Effects of mesoporous SiO2 , Fe3 O4 , and TiO2 nanoparticles on the biological functions of endothelial cells in vitro.  

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To comparatively investigate the cytotoxicities of nanomaterials in circulation, in this study, three different types of nanoparticles (NPs; mesoporous SiO2, Fe3O4, and TiO2) with diameters of around 100 nm were synthesized. The morphologies, crystalline phases, and zeta potentials of those NPs were characterized by scanning electron microscopy, X-ray diffraction and zeta potential measurement, respectively. Then, we investigated the influences of different NPs on the biological functions of endothelial cells, in particular of the organelle of cells. The results indicated that different types of NPs had cytotoxic effects in a dose- and time-dependent manner, and there was no significant difference in cytotoxicity between SiO2 and Fe3O4 at concentrations <0.20 mg/mL. The shape and surface charges of NPs greatly affected cellular internalization. We found that cytoskeleton and integrity of cells were destroyed by different NPs. Additionally, the production of reactive oxygen species damaged the mitochondria of cells, in turn leading to cells apoptosis and death. PMID:23776183

Hou, Yanhua; Lai, Min; Chen, Xiuyong; Li, Jinghua; Hu, Yan; Luo, Zhong; Ding, Xingwei; Cai, Kaiyong

2014-06-01

313

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

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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.

Stamopoulos, D.; Manios, E.; Gogola, V.; Benaki, D.; Bouziotis, P.; Niarchos, D.; Pissas, M.

2008-12-01

314

Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity  

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Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/PCL-NCs) have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA) as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. Tensile strength was improved with the addition of 5.0 wt. % of ORS/Fe3O4-NCs. The antibacterial activities of the ORS/Fe3O4/PCL-NC films were examined against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) by diffusion method using nutrient agar. The results indicated that ORS/Fe3O4/PCL-NC films possessed a strong antibacterial activity with the increase in the percentage of ORS/Fe3O4-NCs in the PCL. PMID:25318051

Khandanlou, Roshanak; Ahmad, Mansor B.; Shameli, Kamyar; Saki, Elnaz; Kalantari, Katayoon

2014-01-01

315

Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity  

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Full Text Available Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, Thermogravimetric analysis (TGA and Fourier transform infrared spectroscopy (FT-IR. The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. Tensile strength was improved with the addition of 5.0 wt. % of ORS/Fe3O4-NCs. The antibacterial activities of the ORS/Fe3O4/PCL-NC films were examined against Gram-negative bacteria (Escherichia coli and Gram-positive bacteria (Staphylococcus aureus by diffusion method using nutrient agar. The results indicated that ORS/Fe3O4/PCL-NC films possessed a strong antibacterial activity with the increase in the percentage of ORS/Fe3O4-NCs in the PCL.

Roshanak Khandanlou

2014-10-01

316

Paclitaxel-Fe3O4 nanoparticles inhibit growth of CD138–  CD34– tumor stem-like cells in multiple myeloma-bearing mice  

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Full Text Available Cuiping Yang,1,3,* Jing Wang,2,* Dengyu Chen,1,* Junsong Chen,1 Fei Xiong,4 Hongyi Zhang,1 Yunxia Zhang,2 Ning Gu,4 Jun Dou11Department of Pathogenic Biology and Immunology, Medical School, 2Department of Gynecology and Obstetrics, Zhongda Hospital, Southeast University, Nanjing, 3Department of Pathogenic Biology and Immunology, School of Basic Medicine, Jiangxi University of Traditional Chinese Medicine, Nanchang, 4School of Biological Science and Medical Engineering, Southeast University, Nanjing, People’s Republic of China*These authors contributed equally to this workBackground: There is growing evidence that CD138– CD34– cells may actually be tumor stem cells responsible for initiation and relapse of multiple myeloma. However, effective drugs targeted at CD138– CD34– tumor stem cells are yet to be developed. The purpose of this study was to investigate the inhibitory effect of paclitaxel-loaded Fe3O4 nanoparticles (PTX-NPs on CD138– CD34– tumor stem cells in multiple myeloma-bearing mice.Methods: CD138– CD34– cells were isolated from a human U266 multiple myeloma cell line using an immune magnetic bead sorting method and then subcutaneously injected into mice with nonobese diabetic/severe combined immunodeficiency to develop a multiple myeloma-bearing mouse model. The mice were treated with Fe3O4 nanoparticles 2 mg/kg, paclitaxel 4.8 mg/kg, and PTX-NPs 0.64 mg/kg for 2 weeks. Tumor growth, pathological changes, serum and urinary interleukin-6 levels, and molecular expression of caspase-3, caspase-8, and caspase-9 were evaluated.Results: CD138– CD34– cells were found to have tumor stem cell characteristics. All the mice developed tumors in 40 days after injection of 1 × 106 CD138– CD34– tumor stem cells. Tumor growth in mice treated with PTX-NPs was significantly inhibited compared with the controls (P <  0.005, and the groups that received nanoparticles alone (P < 0.005 or paclitaxel alone (P < 0.05. In addition, the PTX-NPs markedly inhibited interleukin-6 secretion, increased caspase-8, caspase-9, and caspase-3 expression, and induced apoptosis of tumor cells in the treated mice.Conclusion: PTX-NPs proved to be a potent anticancer treatment strategy that may contribute to targeted therapy for multiple myeloma tumor stem cells in future clinical trials.Keywords: multiple myeloma, tumor stem cells, Fe3O4 nanoparticles, paclitaxel

Yang C

2013-04-01

317

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.

318

Separation and preconcentration of trace amounts of silver (I) in water samples based on dithizone modified sodium dodecyl sulfate-coated Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

Complete text of publication follows. Using magnetic nanoparticles for separation and preconcentration in analytical chemistry is opening a new methodology that is faster, simpler and more precise than old ones. In this work, a simple and reliable solid-phase extraction method has been developed to selectively separate and preconcentrate trace amounts of silver (I) from aqueous samples for subsequent measurement by atomic absorption spectrometry. Silver ion was adsorbed quantitatively from aqueous solution onto magnetic nano-adsorbent with dithizone (DTZ) immobilized on sodium dodecyl sulfate (SDS)-coated Fe3O4 nanoparticles (DTZ-S-IONPs). SDS as a surfactant makes admicelle on the surface of Fe3O4 nanoparticles, which allows the metal complexing agent of DTZ, to be immobilized in its hydrocarbon cores. This assemble, as a chelating adsorbent, has made the separation and preconcentration of silver ion possible. It is shown that the novel magnetic nano-adsorbent is quite efficient for the adsorption and desorption of silver (I) at 25 deg C. Different parameters such as pH, temperature, ionic strength, equilibrium time, type and least amount of stripping solution were optimized. The effect of some co-existing ions on the determination was investigated. An aqueous solution containing thiourea has been used in order to selectively desorb the adsorbed silver ion from the surface of the adsorbent. No serious interferences have beesorbent. No serious interferences have been observed due to the presence of another species in the sample. The separation selectivity of the adsorbent for other cations was studied. To improve this, EDTA was added to the source solution before applying to the DTZ-S-IONPs as chelating adsorbent. The procedure was applied for analysis of two real samples. The method is simple and inexpensive. This research was supported by the Department of Chemistry and Nanoscience and Nanotechnology Research Laboratory (NNRL) Payame Noor University of Sirjan.

319

Multifunctional uniform core-shell Fe3O4@mSiO2 mesoporous nanoparticles for bimodal imaging and photothermal therapy.  

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Multimodal imaging and simultaneous therapy is highly desirable because it can provide complementary information from each imaging modality for accurate diagnosis and, at the same time, afford an imaging-guided focused tumor therapy. In this study, indocyanine green (ICG), a near-infrared (NIR) imaging agent and perfect NIR light absorber for laser-mediated photothermal therapy, was successfully incorporated into superparamagnetic Fe(3)O(4)@mSiO(2) core-shell nanoparticles to combine the merit of NIR/magnetic resonance (MR) bimodal imaging properties with NIR photothermal therapy. The resultant nanoparticles were homogenously coated with poly(allylamine hydrochloride) (PAH) to make the surface of the composite nanoparticles positively charged, which would enhance cellular uptake driven by electrostatic interactions between the positive surface of the nanoparticles and the negative surface of the cancer cell. A high biocompatibility of the achieved nanoparticles was demonstrated by using a cell cytotoxicity assay. Moreover, confocal laser scanning microscopy (CLSM) observations indicated excellent NIR fluorescent imaging properties of the ICG-loaded nanoparticles. The relatively high r(2) value (171.6 mM(-1) s(-1)) of the nanoparticles implies its excellent capability as a contrast agent for MRI. More importantly, the ICG-loaded nanoparticles showed perfect NIR photothermal therapy properties, thus indicating their potential for simultaneous cancer diagnosis as highly effective NIR/MR bimodal imaging probes and for NIR photothermal therapy of cancerous cells. PMID:23225542

Li, Jingguo; Jiang, Hao; Yu, Zhiqiang; Xia, Hongyan; Zou, Gang; Zhang, Qijin; Yu, Yue

2013-02-01

320

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.