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Sample records for silica-coated fe3o4 nanoparticles

  1. 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

  2. Preparation of Fe3O4 encapsulated-silica sulfonic acid nanoparticles and study of their in vitro antimicrobial activity.

    Science.gov (United States)

    Naeimi, Hossein; Nazifi, Zahra Sadat; Amininezhad, Seyedeh Matin

    2015-08-01

    A simple and efficient method for the functionalization of silica-coated Fe3O4 magnetic nanoparticles (Fe3O4@SiO2) using chlorosulfonic acid is described. The prepared compounds were screened for antibacterial activity against Escherichia coli (E. coli ATCC 25922) and Staphylococcus aureus (S. aureus ATCC 25923) under UV-light and dark conditions. It was found that the Fe3O4@SiO2-SO3H was significantly indicated the higher photocatalytic inactivation than both Fe3O4 and Fe3O4@SiO2 against E. coli in compared with S. aureus. Furthermore, the inactivation efficiency against both organisms under light conditions has been higher than this efficiency under dark conditions. PMID:26092181

  3. 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.

  4. 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.

  5. Magnetic Pickering emulsions stabilized by Fe3O4 nanoparticles.

    Science.gov (United States)

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

    2011-04-01

    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

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

    Science.gov (United States)

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

    2013-07-01

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

  7. 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

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

    OpenAIRE

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

    2013-01-01

    Acrylic acid and styrene were polymerized onto monodispersed Fe3O4 nanoparticles using a grafting copolymerization method. Aniline molecules were then bonded onto the Fe3O4 nanoparticles by electrostatic self-assembly and further polymerized to obtain uniform polyaniline/Fe3O4 (PANI/Fe3O4) nanoparticles (approximately 35 nm). Finally, monodispersed Ag/PANI/Fe3O4 nanoparticles were prepared by an in situ reduction reaction between emeraldine PANI and silver nitrate. Fourier transform infrared...

  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. Fe3O4@ZIF-8: magnetically recoverable catalysts by loading Fe3O4 nanoparticles inside a zinc imidazolate framework.

    Science.gov (United States)

    Schejn, Aleksandra; Mazet, Thomas; Falk, Véronique; Balan, Lavinia; Aranda, Lionel; Medjahdi, Ghouti; Schneider, Raphaël

    2015-05-27

    A simple methodology for encapsulating ca. 10 nm-sized superparamagnetic Fe3O4 nanoparticles in zeolitic imidazolate frameworks (ZIF-8) crystals was developed. The corresponding Fe3O4@ZIF-8 heterostructured material exhibits bifunctional properties with both high magnetization (Fe3O4) and high thermal stability, large specific surface, and catalytic properties (ZIF-8). The Fe3O4@ZIF-8 catalyst exhibits fair separation ability and reusability, which can be repeatedly applied for Knoevenagel condensations and Huisgen cycloadditions for at least ten successive cycles. PMID:25955275

  11. 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)

  12. Influence of carbon nanotubes support on the morphology of Fe3O4 nanoparticles

    Science.gov (United States)

    Zabihi, F.; Taleshi, F.; Salmani, A.; Pahlavan, A.; Dehghan-niarostami, N.; Vadadi, M. M.

    2015-03-01

    In this paper, the effects of carbon nanotubes as a support to the morphology and size of Fe3O4 magnetic nanoparticles have been investigated. The synthesis of Fe3O4/CNTs nanocomposite powder was performed by the direct precipitation method through ferric chloride (II) and (III) at room temperature. The prepared samples were analyzed by X-ray diffraction spectra, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The results demonstrated considerable changes in the Fe3O4 nanoparticle size, also the morphology of Fe3O4/CNTs nanocomposite powder from agglomerative into rode shape.

  13. Spectroscopic characterization of magnetic Fe3O4@Au core shell nanoparticles

    Science.gov (United States)

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

    2015-04-01

    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 10 ppm 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.

  14. Fe3O4 nanoparticles grown on graphene as advanced electrode materials for supercapacitors

    Science.gov (United States)

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

    2014-01-01

    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.

  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. 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.

  17. 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

  18. 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. 99mTc radiolabelling of Fe3O4-Au core-shell and Au-Fe3O4 dumbbell-like nanoparticles

    Science.gov (United States)

    Felber, M.; Alberto, R.

    2015-04-01

    The development of nanoparticle-based dual-modality probes for magnetic resonance imaging (MRI) and positron emission tomography (PET) or single photon emission computed tomography (SPECT) is increasingly growing in importance. One of the most commonly used radionuclides for clinical SPECT imaging is 99mTc and the labelling of Fe3O4 nanoparticles with 99mTc was shown to be a successful strategy to obtain dual-modality imaging agents. In this work, we focus on gold containing magnetic nanomaterials. The radiolabelling of magnetic Fe3O4-Au core-shell and Fe3O4-Au dumbbell-like nanoparticles with the [99mTc(CO)3]+ fragment is described. The key elements for this 99mTc labelling approach are novel coating ligands, consisting of an anchor for the Au surface, a polyethylene glycol linker and a strong chelator for the [99mTc(CO)3]+ moiety.The development of nanoparticle-based dual-modality probes for magnetic resonance imaging (MRI) and positron emission tomography (PET) or single photon emission computed tomography (SPECT) is increasingly growing in importance. One of the most commonly used radionuclides for clinical SPECT imaging is 99mTc and the labelling of Fe3O4 nanoparticles with 99mTc was shown to be a successful strategy to obtain dual-modality imaging agents. In this work, we focus on gold containing magnetic nanomaterials. The radiolabelling of magnetic Fe3O4-Au core-shell and Fe3O4-Au dumbbell-like nanoparticles with the [99mTc(CO)3]+ fragment is described. The key elements for this 99mTc labelling approach are novel coating ligands, consisting of an anchor for the Au surface, a polyethylene glycol linker and a strong chelator for the [99mTc(CO)3]+ moiety. Electronic supplementary information (ESI) available: Analyses of Fe3O4-Au core-shell nanoparticles; analyses of Au-Fe3O4 dumbbell-like nanoparticles; 99mTc labelling of Fe3O4-Au core-shell nanoparticles; 99mTc complexes; 99mTc labelling of Au-Fe3O4 dumbbell-like nanoparticles; syntheses coating ligands. See DOI: 10.1039/c5nr00269a

  20. Preparation, characterization and SRXPS study of polyvinyl alcohol modified Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    In this study, Fe3O4 nanoparticles were coated with PVA to synthesize PVA-Fe3O4 complex, which were characterized by transmission electron microscopy(TEM),thermo gravimetric(TG) analysis, UV-vis spectra,zeta potentials and ICP-MS, in terms of the physicochemical properties, while surface constituents, structures and chemical bonds of the modified and unmodified nanoparticles were characterized with synchrotron radiation X-ray photoelectron spectroscopy(SRXPS), for exploring modification mechanism of the PVA-Fe3O4. The results indicate that after PVA modification, the suspension stability of Fe3O4 nanoparticles in water and cellular uptake capability were significantly improved compared with unmodified Fe3O4. The SRXPS analysis reveals that the hydroxy groups on the surface of Fe3O4 nanoparticles and PVA were combined by hydrogen bond to consist a stable system, which would be beneficial to the biomedical applications of Fe3O4 nanoparticles. (authors)

  1. Preparation of CNC-dispersed Fe3O4 nanoparticles and their application in conductive paper.

    Science.gov (United States)

    Liu, Kai; Nasrallah, Joseph; Chen, Lihui; Huang, Liulian; Ni, Yonghao

    2015-08-01

    Well-dispersed Fe3O4 nanoparticles (NPs) were synthesized by a co-precipitation method in the presence of cellulose nano-crystals (CNC) as the template. The thus prepared Fe3O4 NPs were then used as a coating agent for the preparation of conductive paper. Fourier transform infrared spectroscopy (FTIR) results revealed that the Fe3O4 NPs were immobilized on the CNC through interactions between the hydroxyl groups of CNC and Fe3O4. Scanning transmission electron microscopy (STEM) images showed that the Fe3O4 NPs prepared in the presence of CNC can be dispersed in the CNC network, while the Fe3O4 NPs prepared in the absence of CNC tended to aggregate in aqueous solutions. The conductivity of the Fe3O4 NPs coated paper can reach to 0.0269S/m at the coating amount of 14.75g/m(2) Fe3O4/CNC nanocomposites. Therefore, the thus obtained coated paper can be potentially used as anti-static packaging material in the packaging field. PMID:25933536

  2. A Facile Solvothermal Synthesis of Octahedral Fe3O4 Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ooi, Frances; DuChene, Joseph S.; Qiu, Jianqing; Graham, Jeremy O.; Engelhard, Mark H.; Cao, Guixin; Gai, Zheng; Wei, Wei

    2015-06-01

    Magnetic nanoparticles are of great technological interest because they promise numerous potential opportunities in biomedicine and data storage. Although intriguing, these applications require exquisite control over nanostructure morphology in order to appropriately harness their magnetic properties. Most synthesis strategies reported to date are unable to routinely produce anisotropic Fe3O4 nanostructures with appropriate sizes to enable integration into biological systems. Here, we report a simple solvothermal synthesis for obtaining octahedral Fe3O4 nanoparticles with suitable sizes for cellular internalization. Furthermore, these ferromagnetic Fe3O4 octahedrons exhibit substantial saturation magnetization with minimal remanence, suggesting their potential applicability for a host of biomedical applications.

  3. 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.

  4. Magnetic and rheological properties of monodisperse Fe3O4 nanoparticle/organic hybrid

    International Nuclear Information System (INIS)

    Fe3O4 nanoparticle/organic hybrids were synthesized via hydrolysis using iron (III) acetylacetonate at ?80 deg. C. The synthesis of Fe3O4 was confirmed by X-ray diffraction, selected-area diffraction, and X-ray photoelectron spectroscopy. Fe3O4 nanoparticles in the organic matrix had diameters ranging from 7 to 13 nm depending on the conditions of hydrolysis. The saturation magnetization of the hybrid increased with an increase in the particle size. When the hybrid contained Fe3O4 particles with a size of less than 10 nm, it exhibited superparamagnetic behavior. The blocking temperature of the hybrid containing Fe3O4 particles with a size of 7.3 nm was 200 K, and it increased to 310 K as the particle size increased to 9.1 nm. A hybrid containing Fe3O4 particles of size greater than 10 nm was ferrimagnetic, and underwent Verwey transition at 130 K. Under a magnetic field, a suspension of the hybrid in silicone oil revealed the magnetorheological effect. The yield stress of the fluid was dependent on the saturation magnetization of Fe3O4 nanoparticles in the hybrid, the strength of the magnetic field, and the amount of the hybrid

  5. 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.

  6. Synthesis of Fe3O4 nanoparticles and its antibacterial application

    Science.gov (United States)

    Prabhu, Y. T.; Rao, K. Venkateswara; Kumari, B. Siva; Kumar, Vemula Sesha Sai; Pavani, Tambur

    2015-02-01

    The Present work outlines the antibacterial activity of Fe3O4 nanoparticles synthesized through chemical combustion method where ferric nitrate is used as precursor material and urea as fuel with the assistant of Tween 80, a non-ionic surfactant. The obtained Fe3O4 nanoparticles were characterized by X-ray diffraction, differential thermal analysis/thermo gravimetric analysis (DTA/TGA), particle size analyzer, SEM with EDAX and TEM. Various parameters such as dislocation density, micro strain, analysis of weight loss and surface morphological studies were calculated. The particle size was calculated from XRD and it was found to be 33-40 nm. Using well diffusion method antibacterial activity of Fe3O4 nanoparticles was tested against gram-positive and gram-negative Staphylococus aureus, Xanthomonas, Escherichia coli and Proteus vulgaris. Fe3O4 nanoparticles exhibited strong antibacterial activity against bacterial species.

  7. Synthesis of Fe3O4 Nanoparticles from Ironstone Prepared by Polyethylene Glycol 4000

    Directory of Open Access Journals (Sweden)

    Astuti

    2014-06-01

    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.

  8. 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

  9. Pharmacokinetic parameters and tissue distribution of magnetic Fe3O4 nanoparticles in mice

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2010-10-01

    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

  10. Numerical characterization of magnetically aligned multiwalled carbon nanotube-Fe3O4 nanoparticle complex.

    Science.gov (United States)

    Jia, Xiaolong; Li, Wusheng; Xu, Xianjuan; Li, Wenbin; Cai, Qing; Yang, Xiaoping

    2015-02-11

    Alignment states of one-dimensional multiwalled carbon nanotubes containing various contents of zero-dimensional ferriferrous oxide nanoparticles (MWCNT-Fe3O4) were numerically characterized. MWCNT-Fe3O4 complexes were successfully prepared via in situ surface-initiated atom transfer radical polymerization, followed by a coprecipitation process. The complexes showed strong magnetism, which endowed them with the ability to be aligned under the action of an external magnetic field. The intensity of the magnetic field, loading content of Fe3O4 nanoparticles, and viscosity of dispersing medium, however, all had substantial effects on the alignment degree. To evaluate the alignment effectively and quantitatively, an orientation tensor description based on marking the direction of a single MWCNT in a selected region of optical images was employed. The results showed that MWCNT-Fe3O4 complex containing 26 wt % of Fe3O4 nanoparticles achieved a desirable alignment in deionized water under a magnetic field intensity of 0.10 T. Accordingly, epoxy composites reinforced with such aligned MWCNT-Fe3O4 complexes displayed 12.3 and 10.9% enhancement in tensile strength and modulus, as well as 8.9 and 6.1% enhancement in flexural strength and modulus, respectively. PMID:25597815

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

    International Nuclear Information System (INIS)

    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)

  12. Dumbbell-like Au-Fe3O4 nanoparticles: a new nanostructure for supercapacitors

    Science.gov (United States)

    Liu, Sheng; Guo, Shaojun; Sun, Shouheng; You, Xiao-Zeng

    2015-03-01

    Monodispersed dumbbell-like Au-Fe3O4 nanoparticles (NPs) were synthesized and studied for use in supercapacitors. These dumbbell NPs show Au/Fe3O4-size dependent capacitive behaviors and the 7-14 nm Au-Fe3O4 NPs have the best specific capacitance of 464 F g-1 at 1 A g-1 and capacity retention of 86.4% after 1000 cycles, much larger than pure Fe3O4 NPs (160 F g-1 and 72.8% retention). This capacitive enhancement is believed to arise from the Au-induced increase in electron transfer across the dumbbell-like NPs. Thise report demonstrates a new strategy to enhance oxide NP capacitance for applications in high performance supercapacitors.Monodispersed dumbbell-like Au-Fe3O4 nanoparticles (NPs) were synthesized and studied for use in supercapacitors. These dumbbell NPs show Au/Fe3O4-size dependent capacitive behaviors and the 7-14 nm Au-Fe3O4 NPs have the best specific capacitance of 464 F g-1 at 1 A g-1 and capacity retention of 86.4% after 1000 cycles, much larger than pure Fe3O4 NPs (160 F g-1 and 72.8% retention). This capacitive enhancement is believed to arise from the Au-induced increase in electron transfer across the dumbbell-like NPs. Thise report demonstrates a new strategy to enhance oxide NP capacitance for applications in high performance supercapacitors. Electronic supplementary information (ESI) available: Experimental details and additional figures (Fig. S1 to Fig. S4). See DOI: 10.1039/c5nr00135h

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

    Directory of Open Access Journals (Sweden)

    Ren Y

    2012-05-01

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

  14. Facilely preparation and microwave absorption properties of Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    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

  15. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    Science.gov (United States)

    Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

    2015-02-01

    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.

  16. Monodispersed core-shell Fe3O4(at)Au nanoparticles

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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.

  19. Catalytic performance of Fe3O4 nanoparticles for cyclocondensation synthesis of thiacrown ethers

    Science.gov (United States)

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

    2015-01-01

    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.

  20. Hydrothermal fabrication of octahedral-shaped Fe3O4 nanoparticles and their magnetorheological response

    Science.gov (United States)

    Jung, H. S.; Choi, H. J.

    2015-05-01

    Octahedral-shaped Fe3O4 nanoparticles were synthesized in the presence of 1,3-diaminopropane using a hydrothermal method and assessed as a potential magnetorheological (MR) material. Their morphology, crystal structure, and magnetic properties were examined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry, respectively. The MR characteristics of the octahedral-shaped, Fe3O4 nanoparticle-based MR particles when dispersed in silicone oil with a 10 vol. % particle concentration were examined using a rotational rheometer under an external magnetic field. The resulting MR fluids exhibited a Bingham-like behavior with a distinctive yield stress from their flow curves.

  1. The Nature of Magnetic State of Small Fe3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

    J. Dolinšek

    2011-12-01

    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.

  2. Synthesis and characterization of Fe3O4 nanoparticles coated with fucan polysaccharides

    International Nuclear Information System (INIS)

    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. - Highlights: • Syntheses of fucan-coated Fe3O4 nanoparticles were made by co-precipitation method. • The efficiency of polysaccharide coated was analyzed by XRD and FT-IR. • The magnetic nanoparticles mean size was 10–20 nm. • The fucan-coated magnetite nanoparticles showed superparamagnetic behavior

  3. 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.

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

    International Nuclear Information System (INIS)

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

  5. Green synthesis and characterization of superparamagnetic Fe 3O 4 nanoparticles

    Science.gov (United States)

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

    2010-07-01

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

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

    Science.gov (United States)

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

    2012-01-01

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

  7. Effect of Fe3O4 magnetic nanoparticles on lysozyme amyloid aggregation

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

    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)

  9. Magnetic Fe3O4@chitosan nanoparticle: synthesis, characterization and application as catalyst carrier.

    Science.gov (United States)

    He, Linghao; Yao, Lu; Liu, Fujun; Qin, Bing; Song, Rul; Huang, Wei

    2010-10-01

    A novel method was developed to prepare Fe3O4@CS beads with core-shell structure using a double-crosslinking process. Before the coating process, an unique crosslinking agent, glutaraldehyde (GA), was adsorbed onto the surface of Fe3O4 in advance, so the subsequent CS can uniformly coat around the magnetic core processed from the strong interaction between GA and CS, forming a perfect core-shell structure. The obtained Fe3O4@CS beads were followed by the Pd deposition through in-situ reduction method, and the prepared composite catalyst was applied exemplarily in synthesizing nabumetone to check its reusing property. The nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and the magnetic hysteresis loop determination method. This novel composite catalyst showed admirable potential in reusable catalysis. PMID:21137729

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

    Directory of Open Access Journals (Sweden)

    Chen DZ

    2012-09-01

    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

  11. 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.

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

    OpenAIRE

    MH Yazdi; Z Najafi Niazzadeh; Khorramizadeh MR; M. Amini; AR Shahverdi

    2012-01-01

    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...

  13. Controlled synthesis of Fe3O4/ZIF-8 nanoparticles for magnetically separable nanocatalysts.

    Science.gov (United States)

    Pang, Fei; He, Mingyuan; Ge, Jianping

    2015-04-27

    Fe3O4/ZIF-8 nanoparticles were synthesized through a room-temperature reaction between 2-methylimidazolate and zinc nitrate in the presence of Fe3O4 nanocrystals. The particle size, surface charge, and magnetic loading can be conveniently controlled by the dosage of Zn(NO3)2 and Fe3O4 nanocrystals. The as-prepared particles show both good thermal stability (stable to 550?°C) and large surface area (1174?m(2) g(-1)). The nanoparticles also have a superparamagnetic response, so that they can strongly respond to an external field during magnetic separation and disperse back into the solution after withdrawal of the magnetic field. For the Knoevenagel reaction, which is catalyzed by alkaline active sites on external surface of catalyst, small Fe3O4/ZIF-8 nanoparticles show a higher catalytic activity. At the same time, the nanocatalysts can be continuously used in multiple catalytic reactions through magnetic separation, activation, and redispersion with little loss of activity. PMID:25766136

  14. 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

  15. Formation of multifunctional Fe3O4/Au composite nanoparticles for dual-mode MR/CT imaging applications

    Science.gov (United States)

    Hu, Yong; Li, Jing-Chao; Shen, Ming-Wu; Shi, Xiang-Yang

    2014-07-01

    Recent advances with iron oxide/gold (Fe3O4/Au) composite nanoparticles (CNPs) in dual-modality magnetic resonance (MR) and computed tomography (CT) imaging applications are reviewed. The synthesis and assembly of “dumbbelllike” and “core/shell” Fe3O4/Au CNPs is introduced. Potential applications of some developed Fe3O4/Au CNPs as contrast agents for dual-mode MR/CT imaging applications are described in detail.

  16. Characterization and immobilization of trypsin on tannic acid modified Fe3O4 nanoparticles.

    Science.gov (United States)

    Atacan, Keziban; Özacar, Mahmut

    2015-04-01

    Fe3O4 nanoparticles (NPs) were synthesized by co-precipitating Fe(2+) and Fe(3+) in an ammonia solution. Fe3O4 NPs functionalized with tannic acid were prepared. After functionalization process, trypsin enzyme was immobilized on these Fe3O4 NPs. The influence of pH, temperature, thermal stability, storage time stability and reusability on non-covalent immobilization was studied. The properties of Fe3O4 and its modified forms were examined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), UV-vis spectrometer (UV) and X-ray diffraction (XRD), magnetization and zeta potential measurements. The immobilized enzyme was slightly more stable than the free enzyme at 45°C. According to the results, the activity of immobilized trypsin was preserved 55% at 45°C after 2h and 90% after 120 days storage. In addition, the activity of the immobilized trypsin was preserved 40% of its initial activity after eight times of successive reuse. PMID:25686792

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

    OpenAIRE

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

    2009-01-01

    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...

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

    OpenAIRE

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

    2013-01-01

    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...

  19. Competing reactions of selected atmospheric gases on Fe3O4 nanoparticles surfaces.

    Science.gov (United States)

    Eltouny, N; Ariya, Parisa A

    2014-11-14

    Heterogeneous reactions on atmospheric aerosol surfaces are increasingly considered important in understanding aerosol-cloud nucleation and climate change. To understand potential reactions in polluted atmospheres, the co-adsorption of NO2 and toluene to magnetite (Fe3O4i.e. FeO·Fe2O3) nanoparticles at ambient conditions was investigated for the first time. The surface area, size distribution, and morphology of Fe3O4 nanoparticles were characterized by BET method and high-resolution transmission electron microscopy. Adsorption isotherms, collected by gas chromatography with flame ionization detection, showed that the presence of NO2 decreased the adsorption of toluene. The analyses of the surface chemical composition of Fe3O4 by X-ray photoelectron spectroscopy (XPS) reveal that, upon the addition of NO2, the surface is oxidized and a contribution at 532.5 ± 0.4 eV in the O1s spectrum appears, showing that NO2 likely competes with toluene by dissociating on Fe(2+) sites and forming NO3(-). Different competing effects were observed for oxidized Fe3O4; oxidation occurred when exposed solely to NO2, whereas, the mixture of toluene and NO2 resulted in a reduction of the surface i.e. increased Fe(2+)/Fe(3+). Analyses by time of flight secondary ion mass spectrometry further suggest toluene reacts with Fe(3+) sites forming oxygenated organics. Our results indicate that on reduced magnetite, NO2 is more reactive and competes with toluene; in contrast, on oxidized Fe3O4, toluene is more reactive. Because magnetite can assume a range of oxidation ratios in the environment, different competing interactions between pollutants like NO2 and toluene could influence atmospheric processes, namely, the formation of Fe(2+) and the formation of atmospheric oxidants. PMID:25247461

  20. 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.

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

    Science.gov (United States)

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

    2012-08-01

    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

  2. Magnetization enhancement and cation valences in nonstoichiometric (Mn,Fe)3-?O4 nanoparticles

    Science.gov (United States)

    Antic, B.; Kremenovic, A.; Jovic, N.; Pavlovic, M. B.; Jovalekic, C.; Nikolic, A. S.; Goya, G. F.; Weidenthaler, C.

    2012-04-01

    We present a study of the structural and magnetic properties of (Mn,Fe)3-?O4 nanoparticles synthesized by soft mechanochemistry using Mn(OH)2 × 2 H2O and Fe(OH)3 powders as starting compounds. The resulting nanoparticles with a composition of the (Mn,Fe)3-?O4 type are found to have a core/shell structure with different Mn/Fe ratios in the core and at the surface. XPS analysis points to valences of +2, +3, and +4 for Mn and +3 for Fe at the particle surface. Combined results of XRPD, Mössbauer spectroscopy, and EDX analysis suggest that there is a deviation from stoichiometry in the nanoparticle core compared to the shell, accompanied by creation of cation polyvalence and vacancies. The value of saturation magnetization, MS, of 73.5 emu/g at room temperature, is among the highest reported so far among nanocrystalline ferrite systems of similar composition.

  3. Facile synthesis and paramagnetic properties of Fe3O4@SiO2 core-shell nanoparticles

    Science.gov (United States)

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

    2014-12-01

    The Fe3O4@SiO2 core-shell nanoparticles (NPs) had been successfully fabricated via direct decomposition of tetraethyl orthosilicate (TEOS) in solution under the presence of as-synthesized Fe3O4 NPs prepared by chemical coprecipitation method. The structure and magnetic properties of Fe3O4@SiO2 NPs were characterized and the result indicated that Fe3O4@SiO2 NPs are about 12 nm in size with paramagnetic property. The possible growth and magnetic mechanism was discussed in detail.

  4. Synthesis and characterization of ferrocene modified Fe3O4@Au magnetic nanoparticles and its application.

    Science.gov (United States)

    Qiu, Jian-Ding; Xiong, Meng; Liang, Ru-Ping; Peng, Hua-Ping; Liu, Fen

    2009-04-15

    A novel dopamine sensor was fabricated by forming the 6-ferrocenylhexanethiol (HS(CH(2))(6)Fc) functionalized Fe(3)O(4)@Au nanoparticles (NPs) films on the surface of a carbon paste electrode with the aid of a permanent magnet. HS(CH(2))(6)Fc, which acted as the redox mediator, was self-assembled to Fe(3)O(4)@Au NPs via Au-S bond. Transmission electron microscopy, UV-visible absorption spectroscopy, Fourier transform infrared spectra, and cyclic voltammetry were used to characterize the properties of the Fe(3)O(4)@Au NPs/HS(CH(2))(6)Fc nanocomposite. It is shown that the prepared ferrocene-functionalized Fe(3)O(4)@Au NPs composite shuttled electrons between analyte and electrode, increased the mediator loading, and more importantly prevented the leakage of the mediator during measurements, which resulted in the substantially enhanced stability and reproducibility of the modified electrode. The electrooxidation of dopamine could be catalyzed by Fc/Fc(+) couple as a mediator and had a higher electrochemical response due to the unique performance of Fe(3)O(4)@Au NPs. The nanocomposite modified electrode exhibited fast response (3 s) and the linear range was from 2.0x10(-6) to 9.2x10(-4) M with a detection limit of 0.64 microM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of other sensors and bioelectronic devices. PMID:19230651

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

    Science.gov (United States)

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

    2012-07-01

    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 (?(0)H = 6 T), i.e. deviations from the Bloch law at low temperatures (T heating effects (magnetic hyperthermia) are analyzed under the application of an AC magnetic field. Maximum specific absorption rate (SAR) values around 1.5 W g(-1) were achieved for the Fe3O4 nanoparticles. A significant decrease (around 26%) is found in the SAR values of the SiO2 coated nanocomposite. The different heating response is analyzed in terms of the decrease of the effective nanoparticle magnetization in the Fe3O4@SiO2 core-shell composites at room temperature. PMID:22700683

  6. Morphology and magnetic flux distribution in superparamagnetic, single-crystalline Fe3O4 nanoparticle rings

    International Nuclear Information System (INIS)

    This study reports on the correlation between crystal orientation and magnetic flux distribution of Fe3O4 nanoparticles in the form of self-assembled rings. High-resolution transmission electron microscopy demonstrated that the nanoparticles were single-crystalline, highly monodispersed, (25?nm average diameter), and showed no appreciable lattice imperfections such as twins or stacking faults. Electron holography studies of these superparamagnetic nanoparticle rings indicated significant fluctuations in the magnetic flux lines, consistent with variations in the magnetocrystalline anisotropy of the nanoparticles. The observations provide useful information for a deeper understanding of the micromagnetics of ultrasmall nanoparticles, where the magnetic dipolar interaction competes with the magnetic anisotropy.

  7. Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles

    OpenAIRE

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

    2005-01-01

    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 anisotropy $K_{...

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

    Science.gov (United States)

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

    2014-09-01

    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.

  9. Synthesis and characterization of Fe3O4-TiO2 core-shell nanoparticles

    Science.gov (United States)

    Stefan, M.; Pana, O.; Leostean, C.; Bele, C.; Silipas, D.; Senila, M.; Gautron, E.

    2014-09-01

    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.

  10. Study on the Synthesis and Properties of Superparamagnetic Monodisperse Fe3O4 Nanoparticles

    Directory of Open Access Journals (Sweden)

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

    2009-07-01

    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(¢

  11. Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles

    CERN Document Server

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

    2006-01-01

    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...

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

    Science.gov (United States)

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

    2014-05-01

    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

  13. 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

  14. 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

  15. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Teymourian, Hazhir; Salimi, Abdollah; Khezrian, Somayeh

    2013-11-15

    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

  18. 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)

  19. Electrostatic self-assembly of Fe3O4 nanoparticles on carbon nanotubes

    International Nuclear Information System (INIS)

    Carbon nanotubes (CNTs)-based magnetic nanocomposites can find numerous applications in nanotechnology, integrated functional system, and in medicine owing to their great potentialities. Herein, densely distributed magnetic Fe3O4 nanoparticles were successfully attached onto the convex surfaces of carbon nanotubes (CNTs) by an in situ polyol-medium solvothermal method via non-covalent functionalization of CNTs with cationic surfactant, cetyltrimethylammonium bromide (CTAB), and anionic polyelectrolyte, poly(sodium 4-styrenesulfonate) (PSS), through the polymer-wrapping technique, in which the negatively charged PSS-grafted CNTs can be used as primer for efficiently adsorption of positively metal ions on the basis of electrostatic attraction. X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis have been used to study the formation of Fe3O4/CNTs. The Fe3O4/CNTs nanocomposites were proved to be superparamagnetic with saturation magnetization of 43.5 emu g-1. A mechanism scheme was proposed to illustrate the formation process of the magnetic nanocomposites.

  20. Synthesis and characterization of Fe3O4 nanoparticles with perspectives in biomedical applications

    Scientific Electronic Library Online (English)

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

    2014-06-01

    Full Text Available 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.

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

    Directory of Open Access Journals (Sweden)

    Poedji Loekitowati Hariani

    2013-06-01

    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.

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

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    Dorniani D

    2012-11-01

    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

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

    OpenAIRE

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

    2009-01-01

    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 produ...

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

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    Chittor Raghuraman

    2010-12-01

    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.

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

    International Nuclear Information System (INIS)

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

  6. Shock-compression response of magnetic Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    The shock-compression response of magnetic nano-Fe3O4 powders of ?12 nm and ?6 nm, and their bimodal mixture (?12 nm + ?6 nm in a 4:1 ratio), was investigated to determine the densification behavior of nanoparticles and properties of the consolidated magnets. Compacts recovered following shock compaction using a three-capsule, plate-impact, gas-gun setup at impact velocities of ?800 m s-1 and ?1100 m s-1 showed maximal densification of ?80% theoretical maximum density (TMD) for ?12 nm particles, ?70% TMD for ?6 nm particles, and ?75% TMD for the bimodal mixture (?12 nm + ?6 nm in a 4:1 ratio) nanoparticles. Pressure-volume compressibility (Hugoniot) plots of nano-Fe3O4 powder compacts were constructed to assess their dynamic densification behavior. Scanning electron microscopy imaging of the recovered compacts showed the presence of a laminar structure, with inter-layer voids and microscopic gaps between nanoparticle agglomerates, which were responsible for the incomplete consolidation. X-ray diffraction and transmission electron microscopy analyses showed the retention of nanostructure in the recovered compacts, although the shock-energy deposition caused some grain growth. Hysteresis loop measurements revealed that the magnetic properties were retained, and shock compaction did not cause any magnetic transition. The potential causes for the lack of complete densification obsensification observed in the recovered shock-consolidated compacts of nano-Fe3O4 particles are discussed in light of the shock-consolidation mechanisms and interparticle bonding in nano-sized powders.

  7. Study on the adsorption of DNA on Fe3O4 nanoparticles and on ionic liquid-modified Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    We have investigated the adsorption of herring sperm DNA on Fe3O4 magnetic nanoparticles (NPs) before and after modification with the ionic liquid 1-hexyl-3-methylimidazolium bromide. Experiments were performed in a batch mode, and the effects of DNA concentration, pH of the sample solution, ionic strength, temperature, and contact time between reagents were optimized. An evaluation of the adsorption isotherm revealed that the Langmuir model better fits the equilibrium data than the Freundlich model. The maximum adsorption capacities of the unmodified and modified NPs, respectively, were found to be 11.8 and 19.8 mg DNA per gram of adsorbent. The adsorption of DNA onto the modified NPs was endothermic, while it was exothermic in the case of the unmodified NPs. The DNA can be desorbed from the modified surfaces of the NPs by using EDTA as the eluent. The NPs were able to adsorb about 90?±?1.5 % of DNA after being recycled for three times. The method is simple, fast, robust, and does not require organic solvents or sophisticated equipment. (author)

  8. Phospholipid-driven long-range ordering of Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    N-(1-(2,3-dioleoyloxy)propyl)-N,N,N-trimethylammonium chloride (DOTAP) lipid molecules were used to drive the self-assembly of pre-fabricated Fe3O4 nanoparticles (?10 nm in size) into a tightly packed hexagonal array by spin coating. In spite of the relatively wide particle size distribution of the pre-fabricated nanoparticles, the nanoparticles encapsulated by the DOTAP lipid molecules were self-assembled into a two-dimensional superlattice over a large area because the monolayer of DOTAP molecules attached to the particles surface provided the force necessary to anchor the nanoparticles on the substrate surface during spin coating as well as the force necessary to hold the particles together. It is expected that the proposed method can be easily scalable to an industrial process and be also adapted to different nanoparticle systems by appropriate selection of the encapsulating lipid molecules.

  9. Water dispersible oleic acid-coated Fe3O4 nanoparticles for biomedical applications

    Science.gov (United States)

    Shete, P. B.; Patil, R. M.; Tiwale, B. M.; Pawar, S. H.

    2015-03-01

    Fe3O4 magnetic nanoparticles (MNPs) have proved their tremendous potential to be used for various biomedical applications. Oleic acid (OA) is widely used in ferrite nanoparticle synthesis because it can form a dense protective monolayer, thereby producing highly uniform and monodispersed particles. Capping agents such as oleic acid are often used because they form a protective monolayer, which is strongly bonded to the surface of nanoparticles. This is necessary for making monodisperse and highly uniform MNPs. Coating of Fe3O4 MNPs with OA makes the particles dispersible only in organic solvents and consequently limits their use for biomedical applications. Hence, in this work, the OA coated MNPs were again functionalized with chitosan (CS), in order to impart hydrophilicity on their surface. All the morphological, magnetic, colloidal and cytotoxic characteristics of the resulting core-shells were studied thoroughly. Their heating induction ability was studied to predict their possible use in hyperthermia therapy of cancer. Specific absorption rate was found to be increased than that of bare MNPs.

  10. Interface composition between Fe3O4 nanoparticles and GaAs for spintronic applications

    International Nuclear Information System (INIS)

    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

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

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    MH Yazdi

    2012-08-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yazdi MH

    2012-08-01

    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.

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

    Science.gov (United States)

    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

    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.

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

    Directory of Open Access Journals (Sweden)

    Zhao Baobao

    2011-01-01

    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.

  15. Facile deposition of gold nanoparticles on core-shell Fe3O4@polydopamine as recyclable nanocatalyst

    Science.gov (United States)

    Zhao, Yan; Yeh, Yaowen; Liu, Rui; You, Jinmao; Qu, Fengli

    2015-07-01

    A simple and green method for the controllable synthesis of core-shell Fe3O4 polydopamine nanoparticles (Fe3O4@PDA NPs) with tunable shell thickness and their application as a recyclable nanocatalyst support is presented. Magnetite Fe3O4 NPs formed in a one-pot process by the hydrothermal approach with a diameter of ?240 nm were coated with a polydopamine shell layer with a tunable thickness of 15-45 nm. The facile deposition of Au NPs atop Fe3O4@PDA NPs was achieved by utilizing PDA as both the reducing agent and the coupling agent. The satellite nanocatalysts exhibited high catalytic performance for the reduction of p-nitrophenol. Furthermore, the recovery and reuse of the catalyst was demonstrated 8 times without detectible loss in activity. The synergistic combination of unique features of PDA and magnetic nanoparticles establishes these core-shell NPs as a versatile platform for potential applications.

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

    Directory of Open Access Journals (Sweden)

    Mukherjee Joyeeta

    2012-11-01

    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.

  17. Linear birefringence and dichroism in citric acid coated Fe3O4 magnetic nanoparticles

    Science.gov (United States)

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

    2014-12-01

    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.

  18. Break Snoek limit via superparamagnetic coupling in Fe3O4/silica multiple-core/shell nanoparticles

    Science.gov (United States)

    Zhang, Xuefeng; Liu, Yuanyuan; Qin, Gaowu

    2015-01-01

    Natural materials that maintain significant permeability at microwave frequencies are a challenge due to the Snoek limit, but manipulation of matter-microwave interaction in artificial composites provides a possibility to achieve breakthroughs. Herein, we synthesized Fe3O4/silica core/shell nanoparticles comprised of multiple Fe3O4 cores in each particle (denoted as multiple-Fe3O4/silica). In comparison to conventional magnetic natural resonance at megahertz frequencies, the resonance of multiple-Fe3O4/silica composite appears at 9.3 GHz relying on superparamagnetic coupling, which is the highest value reported currently. Our study opens up a fantastic avenue for optimizing micromagnetism by nanoscale architectures.

  19. 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.

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

    OpenAIRE

    Yong Seok Kim; Hyun Jong Lee; Patakamuri Govindaiah; Woohyun Son; Won-Gun Koh; In Woo Cheong; Jung Hyun Kim

    2014-01-01

    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...

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

    Science.gov (United States)

    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

    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.

  2. Spin disorder and magnetic anisotropy in Fe3O4 nanoparticles

    Science.gov (United States)

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

    2006-04-01

    We have studied the magnetic behavior of dextran-coated magnetite (Fe3O4) nanoparticles with median particle size =8 nm. Magnetization curves and in-field Mössbauer spectroscopy measurements showed that the magnetic moment MS of the particles was much smaller than the bulk material. However, we found no evidence of magnetic irreversibility or nonsaturating behavior at high fields, usually associated to spin canting. The values of magnetic anisotropy Keff from different techniques indicate that surface or shape contributions are negligible. It is proposed that these particles have bulklike ferromagnetic structure with ordered A and B sublattices, but nearly compensated the magnetic moments. The dependence of the blocking temperature with frequency and applied fields, TB(H,?), suggests that the observed nonmonotonic behavior is governed by the strength of interparticle interactions.

  3. Functionalized Fe3O4@silica core-shell nanoparticles as microalgae harvester and catalyst for biodiesel production.

    Science.gov (United States)

    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

    2015-03-01

    Core-shell Fe3O4@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 Fe3O4@silica nanoparticles could effectively convert algae oil to biodiesel with a maximum yield of 97.1?%. Additionally, TBD-Fe3O4@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

  4. Differential response of macrophages to core-shell Fe3O4@Au nanoparticles and nanostars

    Science.gov (United States)

    Xia, Wei; Song, Hyon-Min; Wei, Qingshan; Wei, Alexander

    2012-10-01

    Murine RAW 264.7 cells were exposed to spheroidal core-shell Fe3O4@Au nanoparticles (SCS-NPs, ca. 34 nm) or nanostars (NSTs, ca. 100 nm) in the presence of bovine serum albumin, with variable effects observed after macrophagocytosis. Uptake of SCS-NPs caused macrophages to adopt a rounded, amoeboid form, accompanied by an increase in surface detachment. In contrast, the uptake of multibranched NSTs did not induce gross changes in macrophage shape or adhesion, but correlated instead with cell enlargement and signatures of macrophage activation such as TNF-? and ROS. MTT assays indicate a low cytotoxic response to either SCS-NPs or NSTs despite differences in macrophage behavior. These observations show that differences in NP size and shape are sufficient to produce diverse responses in macrophages following uptake.Murine RAW 264.7 cells were exposed to spheroidal core-shell Fe3O4@Au nanoparticles (SCS-NPs, ca. 34 nm) or nanostars (NSTs, ca. 100 nm) in the presence of bovine serum albumin, with variable effects observed after macrophagocytosis. Uptake of SCS-NPs caused macrophages to adopt a rounded, amoeboid form, accompanied by an increase in surface detachment. In contrast, the uptake of multibranched NSTs did not induce gross changes in macrophage shape or adhesion, but correlated instead with cell enlargement and signatures of macrophage activation such as TNF-? and ROS. MTT assays indicate a low cytotoxic response to either SCS-NPs or NSTs despite differences in macrophage behavior. These observations show that differences in NP size and shape are sufficient to produce diverse responses in macrophages following uptake. Electronic supplementary information (ESI) available: Synthetic details, additional TEM images, absorbance spectra, and DLS analysis of SCS-NPs and NSTs, negative and positive control images of ROS imaging, and the effect of magnetic field gradient on ROS production. See DOI: 10.1039/c2nr32070c

  5. Multifunctional luminomagnetic FePt-Fe3O4/SiO2/Rhodamine B/SiO2 nanoparticles with high magnetic emanation for biomedical applications

    International Nuclear Information System (INIS)

    Multifunctional luminomagnetic nanoparticles with average particle diameter around 34 nm and enhanced magnetic properties are reported. FePt-Fe3O4 magnetic nuclei with 6.0 ± 0.7 nm in a core–shell nanostructure were synthesized combining the modified polyol and seed-mediated growth processes, coated with silica by reverse micelle route and annealed. Individual silica-coated magnetic core resulted in a mixture of hard and soft magnetic nanostructured material with superparamagnetic behavior and enhanced magnetic emanation. Luminescent dye Rhodamine B (RhB) was incorporated onto the nanoparticle surface followed by coating with an outer silica shell in a layer-by-layer structure. The bifunctional luminomagnetic nanoparticles of FePt-Fe3O4/SiO2/RhB/SiO2 present high-water dispersibility, colloidal stability, and hydrophilic surface with isoelectric point of 2.7. The superparamagnetic behavior was preserved with blocking temperature of 40 K and the saturation magnetization of the final product equal 64.3 emu g?1 was around ten times higher than observed for nanoparticles using pure magnetite core synthesized in the same conditions. Inner and outer silica layers minimize luminescence quenching processes due to avoid contact between dye and both magnetic core and solvent, respectively, resulting in a stable emission for, at least, 1 h. These properties allied with the possibility to use differed with the possibility to use different dye compounds gives a potential bifunctional nanosensor for biomedical applications.

  6. Controlled manipulation of Fe3O4 nanoparticles in an oscillating magnetic field for fast ablation of microchannel occlusion

    Science.gov (United States)

    Gabayno, Jacque Lynn F.; Liu, Da-Wei; Chang, Ming; Lin, Yu-Hao

    2015-02-01

    Fe3O4 nanoparticles were controlled by an oscillating magnetic field to enable fast and non-contact ablation of microchannel occlusion. Scalable behaviour of their translational and rotational velocities was experimentally verified. Rotational flows created by such motions are fundamental for ablation as demonstrated by the removal of thrombi in occluded microchannels.Fe3O4 nanoparticles were controlled by an oscillating magnetic field to enable fast and non-contact ablation of microchannel occlusion. Scalable behaviour of their translational and rotational velocities was experimentally verified. Rotational flows created by such motions are fundamental for ablation as demonstrated by the removal of thrombi in occluded microchannels. Electronic supplementary information (ESI) available: Additional information on the magnetic properties of the Fe3O4 nanoparticles, setup configuration, and videos of thrombus removal process. See DOI: 10.1039/c4nr06143h

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

    Science.gov (United States)

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

    2013-10-01

    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.

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

    Science.gov (United States)

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

    2015-01-01

    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.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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05342g

  9. Fe3O4/Salicylic acid nanoparticles behavior on chick CAM vasculature

    International Nuclear Information System (INIS)

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

  10. Efficient purification of His-tagged protein by superparamagnetic Fe3O4/Au-ANTA-Co2+ nanoparticles.

    Science.gov (United States)

    Zhang, Lianying; Zhu, Xinjun; Jiao, Dejie; Sun, Yongling; Sun, Hanwen

    2013-05-01

    Superparamagnetic Fe3O4/Au nanoparticles were synthesized and surface modified with mercaptopropionic acid (MPA), followed by conjugating N?,N?-Bis(carboxymethyl)-l-lysine hydrate (ANTA) and subsequently chelating Co(2+). The resulting Fe3O4/Au-ANTA-Co(2+) nanoparticles have an average size of 210 nm in aqueous solution, and a magnetization of 36 emu/g, endowing the magnetic nanoparticles with excellent magnetic responsivity and dispersity. The Co(2+) ions in the magnetic nanoparticle shell provide docking site for histidine, and the Fe3O4/Au-ANTA-Co(2+) nanoparticles exhibit excellent performance in binding of a His-tagged protein with a binding capacity of 74 ?g/mg. The magnetic nanoparticles show highly selective purification of the His-tagged protein from Escherichia coli lysate. Therefore, the obtained Fe3O4/Au-ANTA-Co(2+) nanoparticles exhibited excellent performance in the direct separation of His-tagged protein from cell lysate. PMID:23498223

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    Gan N

    2011-12-01

    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

  13. A novel approach for the synthesis of ultrathin silica-coated iron oxide nanocubes decorated with silver nanodots (Fe3O4/SiO2/Ag) and their superior catalytic reduction of 4-nitroaniline.

    Science.gov (United States)

    Abbas, Mohamed; Torati, Sri Ramulu; Kim, CheolGi

    2015-07-28

    A novel sonochemical approach was developed for the synthesis of different core/shell structures of Fe3O4/SiO2/Ag nanocubes and SiO2/Ag nanospheres. The total reaction time of the three sonochemical steps for the synthesis of Fe3O4/SiO2/Ag nanocubes is shorter than that of the previously reported methods. A proposed reaction mechanism for the sonochemical functionalization of the silica and the silver on the surface of magnetic nanocubes was discussed in detail. Transmission electron microscopy revealed that the surface of Fe3O4/SiO2 nanocubes was decorated with small Ag nanoparticles of approximately 10-20 nm in size, and the energy dispersive spectroscopy mapping analysis confirmed the morphology of the structure. Additionally, X-ray diffraction data were used to confirm the formation of both phases of a cubic inverse spinel structure for Fe3O4 and bcc structures for Ag in the core/shell structure of the Fe3O4/SiO2/Ag nanocubes. The as-synthesized Fe3O4/SiO2/Ag nanocubes showed a high efficiency in the catalytic reduction reaction of 4-nitroaniline to 4-phenylenediamine and a better performance than both Ag and SiO2/Ag nanoparticles. The grafted silver catalyst was recycled and reused at least fifteen times without a significant loss of catalytic efficiency. PMID:26132976

  14. Investigation on transformation of spindle-like Fe3O4 nanoparticles from self-assembling ?-Fe2O3

    Science.gov (United States)

    Huang, Zhaocong; Meng, Hong; Yuan, Shijun; Zhang, Wen; Liu, Er; Zhang, Dong; Kou, Zhaoxia; Zhai, Ya; Wang, Baoping; Zhai, Hongru

    2015-05-01

    Porous monodisperse spindle-like ?-Fe2O3 nanomaterials are first synthesized successfully by a hydrothermal method, and then the as-prepared nanoparticles are annealed at different temperatures under various atmospheres to achieve the spindle-like Fe3O4 nanoparticles. The evolution of the features of nanoparticles, including the changes of the structures and microstructures as well as the magnetic properties, during the reduction process has been investigated by using the Raman spectrum and Mössbauer spectrum. Our research reveals that the ?-Fe2O3 nanoparticles annealed by covering of the C powder become a mixture of ?-Fe2O3 and Fe3O4 in the range of annealing temperature from 300 °C to 800 °C. With reduced atmospheric H2, spindle-like ?-Fe2O3 nanoparticles are transferred to mixture of ?-Fe2O3, Fe3O4 and Fe as temperature increases. They are also converted from a typical rhombohedral structure to a cubic ?-Fe phase at 500 °C. Finally, with the atmosphere of H2/Ar (5%/95%), a pure Fe3O4 phase, and its excellent magnetic properties are achieved at 450 °C.

  15. Optically transparent magnetic nanocomposites based on encapsulated Fe3O4 nanoparticles in a sol-gel silica network

    International Nuclear Information System (INIS)

    Composite Fe3O4-SiO2 materials were prepared by the sol-gel method with tetraethoxysilane and aqueous-based Fe3O4 ferrofluids as precursors. The monoliths obtained were crack free and showed both optical and magnetic properties. The structural properties were determined by infrared spectroscopy, x-ray diffractometry and transmission electron microscopy. Fe3O4 particles of 20 nm size lie within the pores of the matrix without any strong Si-O-Fe bonding. The well established silica network provides effective confinement to these nanoparticles. The composites were transparent in the 600-800 nm regime and the field dependent magnetization curves suggest that the composite exhibits superparamagnetic characteristics

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

    Science.gov (United States)

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

    2015-01-01

    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.

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

    Science.gov (United States)

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

    2015-01-25

    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. PMID:25123943

  18. Magnetic iron oxide (Fe3O4) nanoparticles from tea waste for arsenic removal

    International Nuclear Information System (INIS)

    Magnetic iron oxide nanoparticles (MION-Tea) successfully synthesized using tea waste template. MION-Tea exhibit super magnetic properties under external magnetic field with saturation magnetization value of 6.9 emu/g at room temperature. SEM of MION-Tea shows cuboid/pyramid shaped crystals structure of Fe3O4 (magnetite). TEM of MION-Tea shows the particle size in the range of 5–25 nm. XRD pattern of MION-Tea is identical to magnetite. Magnetic nanoparticles are tested for removal of As(III) and As(V) from aqueous solution. The adsorption data obeyed the Langmuir equation with high adsorption capacity of 188.69 mg/g for arsenic (III), and 153.8 mg/g for arsenic (V). The mean sorption energy (E) calculated from D–R model, indicated physico-chemical sorption process. A pseudo-second-order kinetic model fitted best for As(III) adsorption on MION-Tea and the derived activation energy was 64.27 kJ/mol. Thermodynamics revealed the endothermic nature of adsorption. The effects of solution pH, interfering anions and initial As(III) concentration have been investigated. MION-Tea was very low cost (Rs. 136 per kg). MION-Tea can be reused up to 5 adsorption cycles and regenerated using NaOH. Cost of As(III) removal from water of was estimated to be Rs. 14 for 100 L. Comparison with reported adsorbents proved MION-Tea a potential adsorbent for As(III) and As(V) adsorption. - Highlights: • Used tea has been used to prepare magnetic nanoparticles. • Nanoparticles have particle size of 2-25nm and cuboid/pyramid structure. • Magnetic nanoparticles show high adsorption capacity for arsenic

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

    Directory of Open Access Journals (Sweden)

    Baoan Chen

    2009-11-01

    Full Text Available Baoan Chen1,*, Yiqiong Liang1,*, Weiwei Wu1, Jian Cheng1, Guohua Xia1, Feng Gao1, Jiahua Ding1, Chong Gao1, Zeye Shao1, Guohong Li1, Wenji Chen1, Wenlin Xu2, Xinchen Sun3, Lijie Liu4, Xiaomao Li5, Xuemei 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, Southeast University, Nanjing, People’s Republic of China; 5Department of Physics, University of Saarland, Saarbruechen, Germany; 6State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory, Southeast University, Nanjing, Peoples Republic of China; *These authors have contributed equally to this workAbstract: Gambogic acid (GA has a significant anticancer effect on a wide variety of solid tumors. Recently, many nanoparticles have been introduced as drug-delivery systems to enhance the efficiency of anticancer drug delivery. The aim of this study was to investigate the potential benefit of combination therapy with GA and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4. The proliferation of K562 cells and their cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscope and flow cytometry, respectively. Furthermore, realtime polymerase chain reaction and Western blotting analyses were performed to examine gene transcription and protein expression, respectively. The results showed that MNPs-Fe3O4 dramatically enhanced GA-induced cytotoxicity and apoptosis in K562 cells. The typical morphological features of apoptosis treated with GA and MNPs-Fe3O4 were observed under an optical microscope and a fluorescence microscope, respectively. The transcription of caspase-3 and bax gene in the group treated with GA and MNPs-Fe3O4 was higher than that in the GA-alone group or MNPs-Fe3O4-alone group, but the transcription of bcl-2, nuclear factor-?B, and survivin degraded as did the expression of corresponding proteins in K562 cells. Our data suggests a potential clinical application of a combination of GA and MNPs-Fe3O4 in leukemia therapy.Keywords: gambogic acid, magnetic nanoparticles of Fe3O4, traditional Chinese medicine, K562 leukemia cells, apoptosis

  20. Handling the particle size and distribution of Fe 3O 4 nanoparticles through ball milling

    Science.gov (United States)

    Goya, Gerardo F.

    2004-06-01

    A series of samples consisting of spinel Fe 3O 4 nanoparticles with controlled particle sizes and increasing concentration has been obtained through 'mild' ball milling (BM) experiments by using an organic carrier liquid. We have succeeded in producing quite narrow particle size distributions with mean values ˜7-10 nm by an appropriate choice of the milling time for each concentration. The method proved to be practical to tailor the final particle size without formation of undesirable phases. All samples showed superparamagnetic behavior at room temperature, with transition to a blocked state at T B˜10-20 K. The mean value and distribution width of the size distributions for the three samples studied were obtained from M( H) cycles recorded at T> TB showing good agreement with X-ray diffraction and electron microscopy results. The effect of increasing interparticle interactions was to shift TB upwards, as inferred from magnetization measurements. Mössbauer spectra at low temperatures showed no evidence of enhanced spin disorder.

  1. Multifunctional glucose biosensors from Fe3O4 nanoparticles modified chitosan/graphene nanocomposites

    Science.gov (United States)

    Zhang, Wenjing; Li, Xiaojian; Zou, Ruitao; Wu, Huizi; Shi, Haiyan; Yu, Shanshan; Liu, Yong

    2015-01-01

    Novel water-dispersible and biocompatible chitosan-functionalized graphene (CG) has been prepared by a one-step ball milling of carboxylic chitosan and graphite. Presence of nitrogen (from chitosan) at the surface of graphene enables the CG to be an outstanding catalyst for the electrochemical biosensors. The resulting CG shows lower ID/IG ratio in the Raman spectrum than other nitrogen-containing graphene prepared using different techniques. Magnetic Fe3O4 nanoparticles (MNP) are further introduced into the as-synthesized CG for multifunctional applications beyond biosensors such as magnetic resonance imaging (MRI). Carboxyl groups from CG is used to directly immobilize glucose oxidase (GOx) via covalent linkage while incorporation of MNP further facilitated enzyme loading and other unique properties. The resulting biosensor exhibits a good glucose detection response with a detection limit of 16??M, a sensitivity of 5.658?mA/cm2/M, and a linear detection range up to 26?mM glucose. Formation of the multifunctional MNP/CG nanocomposites provides additional advantages for applications in more clinical areas such as in vivo biosensors and MRI agents. PMID:26052919

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

    Directory of Open Access Journals (Sweden)

    Wang J

    2011-04-01

    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

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

    Science.gov (United States)

    Cunha, C.; Panseri, S.; Iannazzo, D.; Piperno, A.; Pistone, A.; Fazio, M.; Russo, A.; Marcacci, M.; Galvagno, S.

    2012-11-01

    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.

  4. A peroxidase biomimetic system based on Fe3O4 nanoparticles in non-enzymatic sensors.

    Science.gov (United States)

    Guivar, Juan A Ramos; Fernandes, Edson G R; Zucolotto, Valtencir

    2015-08-15

    Magnetic nanoparticles have been applied in many areas of nanomedicine. Sensing platforms based on this type of nanoparticles have received attention due to the relative low cost and biocompatibility. Biosensor is the most widely investigated type of analytical device. This type of sensor combines the physicochemical transduction with the incorporation of biological sensing components. Among the biological components, enzymes are the most commonly used as sensitive elements. However, natural enzymes may exhibit serious disadvantages such as lack of stability and loss of catalytic activity after immobilization. The study of enzymatic biomimetic systems are of great interest. This study reports the development of a new sensor composed of Fe3O4@CTAB and poly(sodium 4-styrenesulfonate) (PSS) films assembled via Layer-by-Layer (LbL) technique and used as peroxidase mimetic systems. Magnetic nanoparticles (MNps) were synthesized using thermal decomposition method and further dispersed to aqueous medium by ligand modification reaction using cetyltrimethylammonium bromide (CTAB). The amperometric detection limit of H2O2 was found to be ca. 103 µmol L(-1). By chronoamperometry, the peroxidase biomimetic sensor exhibited a linear response for H2O2 in the range from 100 µmol L(-1) to 1.8 mmol L(-1) (R(2) = 0.994) with sensitivity of 16 nA mol(-1) L. The apparent Michaelis-Menten constant was 5.3 mmol L(-1), comparable with some biosensors based on peroxidase enzyme. Moreover, the sensor presented a reproducibility of ca. 7.7% (n = 4) and their response (response time: 90 s) is not significantly affected in the presence of some interferents including K(+), Na(+), Cl(-), Mg(2+), Ca(2+), and Uric Acid. PMID:25966419

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

    Directory of Open Access Journals (Sweden)

    Jung Kyoo Lee

    2013-09-01

    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.

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

    OpenAIRE

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

    2013-01-01

    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...

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

    International Nuclear Information System (INIS)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Bao-An Chen

    2010-08-01

    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

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

    Science.gov (United States)

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

    2014-09-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Zhi Jiang

    2009-04-01

    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

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2006-08-01

    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.

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

    International Nuclear Information System (INIS)

    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)

  16. Tailoring size and structural distortion of Fe3O4 nanoparticles for the purification of contaminated water.

    Science.gov (United States)

    Shen, Y F; Tang, J; Nie, Z H; Wang, Y D; Ren, Y; Zuo, L

    2009-09-01

    Fe(3)O(4) magnetic nanoparticles with different particle sizes were synthesized using two methods, i.e., a co-precipitation process and a polyol process, respectively. The atomic pair distribution analyses from the high-energy X-ray scattering data and TEM observations show that the two kinds of nanoparticles have different sizes and structural distortions. An average particle size of 6-8 nm with a narrow size distribution was observed for the nanoparticles prepared with the co-precipitation method. Magnetic measurements show that those particles are in ferromagnetic state with a saturation magnetization of 74.3 emu g(-1). For the particles synthesized with the polyol process, a mean diameter of 18-35 nm was observed with a saturation magnetization of 78.2 emu g(-1). Although both kinds of nanoparticles are well crystallized, an obviously higher structural distortion is evidenced for the co-precipitation processed nanoparticles. The synthesized Fe(3)O(4) particles with different mean particle size were used for treating the wastewater contaminated with the metal ions, such as Ni(II), Cu(II), Cd(II) and Cr(VI). It is found that the adsorption capacity of Fe(3)O(4) particles increased with decreasing the particle size or increasing the surface area. While the particle size was decreased to 8 nm, the Fe(3)O(4) particles can absorb almost all of the above-mentioned metal ions in the contaminated water with the adsorption capacity of 34.93 mg/g, which is approximately 7 times higher than that using the coarse particles. We attribute the extremely high adsorption capacity to the highly-distorted surface. PMID:19414249

  17. 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.

  18. Magnetic solid phase extraction of brominated flame retardants and pentachlorophenol from environmental waters with carbon doped Fe3O4 nanoparticles

    Science.gov (United States)

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

    2014-12-01

    Carbon doped Fe3O4 nanoparticles (Fe3O4/C) prepared by a facile hydrothermal reaction of glucose with iron resource have been applied as magnetic solid-phase extraction (MSPE) sorbent, for the first time, to extract trace brominated flame retardants (BFRs) and pentachlorophenol (PCP) from environmental waters. Various MSPE parameters were optimized including amount of Fe3O4/C nanoparticles, pH of sample solution, enrichment factor of analytes and reusability of Fe3O4/C sorbent. The reliability of the MSPE method was evaluated by the recoveries of BFRs and PCP in spiked water samples. Good recoveries (80.0-110.0%) were achieved with the relative standard deviations range from 0.3% to 6.8%. In this paper, the extraction characteristics of Fe3O4/C sorbent were further elucidated. It is found that the adsorption process of Fe3O4/C to analytes predominates the MSPE efficiency. There is hybrid hydrophobic interaction and hydrogen bonding or dipole-dipole attraction between Fe3O4/C and analytes. Notably, the chemical components of carbon layer on the surface of Fe3O4 nanoparticles were identified by X-ray photoelectron spectroscopy and thermogravimetry-mass spectrometry, and in consequence the covalent bonds between Fe3O4 and the coated carbon have been observed. In addition, the straight influence of synthesis condition of Fe3O4/C nanoparticles including glucose concentration and hydrothermal reaction time on extraction performance for BFRs and PCP has been investigated. It is confirmed that the existence of organic carbon containing functional groups over Fe3O4/C sorbent is responsible for the MSPE extraction.

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

    Science.gov (United States)

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

    2012-10-01

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

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

    Scientific Electronic Library Online (English)

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

    2013-01-01

    Full Text Available 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.

  1. Removal of fluoride from aqueous media by Fe3O4@Al(OH)3 magnetic nanoparticles.

    Science.gov (United States)

    Zhao, Xiaoli; Wang, Jieming; Wu, Fengchang; Wang, Thanh; Cai, Yaqi; Shi, Yali; Jiang, Guibin

    2010-01-15

    A novel magnetic nanosized adsorbent using hydrous aluminum oxide embedded with Fe(3)O(4) nanoparticle (Fe(3)O(4)@Al(OH)(3) NPs), was prepared and applied to remove excessive fluoride from aqueous solution. This adsorbent combines the advantages of magnetic nanoparticle and hydrous aluminum oxide floc with magnetic separability and high affinity toward fluoride, which provides distinctive merits including easy preparation, high adsorption capacity, easy isolation from sample solutions by the application of an external magnetic field. The adsorption capacity calculated by Langmuir equation was 88.48 mg g(-1) at pH 6.5. Main factors affecting the removal of fluoride, such as solution pH, temperature, adsorption time, initial fluoride concentration and co-existing anions were investigated. The adsorption capacity increased with temperature and the kinetics followed a pseudo-second-order rate equation. The enthalpy change (Delta H(0)) and entropy change (DeltaS(0)) was 6.836 kJ mol(-1) and 41.65 J mol(-1)K(-1), which substantiates the endothermic and spontaneous nature of the fluoride adsorption process. Furthermore, the residual concentration of fluoride using Fe(3)O(4)@Al(OH)(3) NPs as adsorbent could reach 0.3 mg L(-1) with an initial concentration of 20 mg L(-1), which met the standard of World Health Organization (WHO) norms for drinking water quality. All of the results suggested that the Fe(3)O(4)@Al(OH)(3) NPs with strong and specific affinity to fluoride could be excellent adsorbents for fluoride contaminated water treatment. PMID:19747775

  2. 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

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

    International Nuclear Information System (INIS)

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

  4. Preparation and characterization of 18-crown-ether-6/LA/Fe3O4 magnetic nanoparticles

    International Nuclear Information System (INIS)

    Fe3O4 Magnetic nanoparticles (MNPs) have the advantages of large specific surface area, high adsorption capacity, and conveniently magnetic separation. Crown ether display good selectivity of coordination with uranyl ion, thorium ion and so on. To combine the feature and advantage, this study prepared for 18-Crown-ether-6/LA/Fe3O4 magnetic particles which with high adsorption and selectivity properties and easy to separate from wastewater with magnet. The structure was characterized with IR, SEM, VSM, DGA and so on. The results reveal that: 18-Crown-ether-6/LA/ Fe3O4 magnetic particles was size of (12-23) nm, saturation magnetization was 56.338 emu/g with superparamagnetism and strong antioxidant properties. A test for the adsorption of the magnetic particles with uranyl ion and thorium ion has been carried out. The results indicated that the magnetic particles had good adsorption capacity, quick efficient and conveniently magnetic separation. It can be used repeatedly, with a good reproducibility. (authors)

  5. Preparation and characterization of core-shell structure Fe3O4/C nanoparticles with unique stability and high electrochemical performance for lithium-ion battery anode material

    International Nuclear Information System (INIS)

    Core-shell structure carbon coating Fe3O4 nanoparticles are prepared by a two-step method. The crystalline structure and the electrochemical performance of the prepared samples are investigated. The results indicate that a uniform and continuous carbon layer is formed on the surface of Fe3O4 nanoparticles. The core-shell structure Fe3O4/C nanoparticles show a high initial discharge capacity of 1546 mAh g-1 and a specific stable discharge capacity of about 800 mAh g-1 at 0.5 C with no noticeable capacity fading up to 100 cycles.

  6. Surfactant-enhanced spectrofluorimetric determination of total aflatoxins from wheat samples after magnetic solid-phase extraction using modified Fe3O4 nanoparticles

    Science.gov (United States)

    Manafi, Mohammad Hanif; Allahyari, Mehdi; Pourghazi, Kamyar; Amoli-Diva, Mitra; Taherimaslak, Zohreh

    2015-07-01

    The extraction and preconcentration of total aflatoxins (including aflatoxin B1, B2, G1, and G2) using magnetic nanoparticles based solid phase extraction (MSPE) followed by surfactant-enhanced spectrofluorimetric detection was proposed. Ethylene glycol bis-mercaptoacetate modified silica coated Fe3O4 nanoparticles as an efficient antibody-free adsorbent was successfully applied to extract aflatoxins from wheat samples. High surface area and strong magnetization properties of magnetic nanoparticles were utilized to achieve high enrichment factor (97), and satisfactory recoveries (92-105%) using only 100 mg of the adsorbent. Furthermore, the fast separation time (less than 10 min) avoids many time-consuming cartridge loading or column-passing procedures accompany with the conventional SPE. In determination step, signal enhancement was performed by formation of Triton X-100 micelles around the analytes in 15% (v/v) acetonitrile-water which dramatically increase the sensitivity of the method. Main factors affecting the extraction efficiency and signal enhancement of the analytes including pH of sample solution, desorption conditions, extraction time, sample volume, adsorbent amount, surfactant concentration and volume and time of micelle formation were evaluated and optimized. Under the optimum conditions, wide linear range of 0.1-50 ng mL-1 with low detection limit of 0.03 ng mL-1 were obtained. The developed method was successfully applied to the extraction and preconcentration of aflatoxins in three commercially available wheat samples and the results were compared with the official AOAC method.

  7. Surfactant-enhanced spectrofluorimetric determination of total aflatoxins from wheat samples after magnetic solid-phase extraction using modified Fe3O4 nanoparticles.

    Science.gov (United States)

    Manafi, Mohammad Hanif; Allahyari, Mehdi; Pourghazi, Kamyar; Amoli-Diva, Mitra; Taherimaslak, Zohreh

    2015-07-01

    The extraction and preconcentration of total aflatoxins (including aflatoxin B1, B2, G1, and G2) using magnetic nanoparticles based solid phase extraction (MSPE) followed by surfactant-enhanced spectrofluorimetric detection was proposed. Ethylene glycol bis-mercaptoacetate modified silica coated Fe3O4 nanoparticles as an efficient antibody-free adsorbent was successfully applied to extract aflatoxins from wheat samples. High surface area and strong magnetization properties of magnetic nanoparticles were utilized to achieve high enrichment factor (97), and satisfactory recoveries (92-105%) using only 100mg of the adsorbent. Furthermore, the fast separation time (less than 10min) avoids many time-consuming cartridge loading or column-passing procedures accompany with the conventional SPE. In determination step, signal enhancement was performed by formation of Triton X-100 micelles around the analytes in 15% (v/v) acetonitrile-water which dramatically increase the sensitivity of the method. Main factors affecting the extraction efficiency and signal enhancement of the analytes including pH of sample solution, desorption conditions, extraction time, sample volume, adsorbent amount, surfactant concentration and volume and time of micelle formation were evaluated and optimized. Under the optimum conditions, wide linear range of 0.1-50ngmL(-1) with low detection limit of 0.03ngmL(-1) were obtained. The developed method was successfully applied to the extraction and preconcentration of aflatoxins in three commercially available wheat samples and the results were compared with the official AOAC method. PMID:25804513

  8. One step grafting of iron phthalocyanine containing flexible chains on Fe3O4 nanoparticles towards high performance polymer magnetic composites

    Science.gov (United States)

    Pu, Zejun; Zhou, Xuefei; Yang, Xulin; Jia, Kun; Liu, Xiaobo

    2015-07-01

    To develop high-performance inorganic particles/polymer composites, the interfacial interaction and dispersion of inorganic particles are the two essential issues to be considered. Herein, we report an effective approach to graft iron phthalocyanine containing flexible chains (NP-ph) on Fe3O4 nanoparticles (NP-ph@Fe3O4). The hybrids were monodispersed solid nanoparticles with the average diameter of about 250 nm. About 16.8% of the phthalocyanine oligomer was incorporated into the resulting NP-ph@Fe3O4 nanoparticles. The NP-ph@Fe3O4 nanoparticles were subsequently used as the novel filler for preparation of high performance poly(arylene ether nitrile)s (PAEN) composites. The scanning electron microscopy (SEM) investigation showed that the NP-ph@Fe3O4 nanoparticles present better dispersion and interfacial compatibility with PAEN matrix than that of raw Fe3O4, which was further confirmed by rheological study. Consequently, the improved thermal stability and enhanced mechanical properties were obtained from composites using NP-ph@Fe3O4. Vibrating sample magnetometer (VSM) results showed that the prepared PAEN composites exhibited higher saturation magnetization and soft magnetic properties. Meanwhile, the saturation magnetization (Ms) of the PAEN/NP-ph@Fe3O4 composite films increased with the increase of the hybrid nanoparticles loading. Thus, the PAEN/NP-ph@Fe3O4 composite would find potential applications in organic magnetic films fields due to their high thermal stability, excellent flexibility and tunable magnetic properties

  9. FMR study of carbon nanotubes filled with Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    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. - Highlights: • Synthesis of CNTs inside of alumina membrane and filling it with Fe3O4 particles. • X-ray diffraction and electron microscopy study of the samples. • Magnetic properties of the samples studied by FMR. • Filling factor has been determined from the angular dependences of FMR. • Resulted magnetic CNTs are attractive for production of magnetic nanofluids

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

    International Nuclear Information System (INIS)

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

  11. 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.

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

    Science.gov (United States)

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

    2013-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Rosfarizan Mohamad

    2013-05-01

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

  14. Recyclable enzyme mimic of cubic Fe3O4 nanoparticles loaded on graphene oxide-dispersed carbon nanotubes with enhanced peroxidase-like catalysis and electrocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hua; Li, Shuai; Si, Yanmei; Sun, Zhongzhao; Li, Shuying; Lin, Yuehe

    2014-01-01

    Fe3O4 nanoparticles as nanocatalysts may present peroxidase-like catalysis activities and high electrocatalysis if loaded on conductive carbon nanotube (CNT) supports; however, their catalysis performances in an aqueous system might still be challenged by the poor aqueous dispersion of hydrophobic carbon supports and/or low stability of loaded iron catalysts. In this work, amphiphilic graphene oxide nanosheets were employed as “surfactant” to disperse CNTs to create stable graphene oxide-dispersed CNT (GCNT) supports in water for covalently loading cubic Fe3O4 nanoparticles with improved distribution and binding efficiency. Compared with original Fe3O4 nanos and CNT-loaded Fe3O4 nanocomplex, the prepared GCNT–Fe3O4 nanocomposite could achieve higher aqueous stability and, especially, much stronger peroxidase-like catalysis and electrocatalysis to H2O2, presumably resulting from the synergetic effects of two conductive carbon supports and cubic Fe3O4 nanocatalysts effectively loaded. Colorimetric and direct electrochemical detections of H2O2 and glucose using the GCNT–Fe3O4 nanocomposite were conducted with high detection sensitivities, demonstrating the feasibility of practical sensing applications. Such a magnetically recyclable “enzyme mimic” may circumvent some disadvantages of natural protein enzymes and common inorganic catalysts, featuring the multi-functions of high peroxidase-like catalysis, strong electrocatalysis, magnetic separation/recyclability, environmental stability, and direct H2O2 electrochemistry.

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

    Science.gov (United States)

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

    2015-01-01

    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.

  16. Hierarchically porous MnO2 microspheres doped with homogeneously distributed Fe3O4 nanoparticles for supercapacitors.

    Science.gov (United States)

    Zhu, Jian; Tang, Shaochun; Xie, Hao; Dai, Yuming; Meng, Xiangkang

    2014-10-22

    Hierarchically porous yet densely packed MnO2 microspheres doped with Fe3O4 nanoparticles are synthesized via a one-step and low-cost ultrasound assisted method. The scalable synthesis is based on Fe(2+) and ultrasound assisted nucleation and growth at a constant temperature in a range of 25-70 °C. Single-crystalline Fe3O4 particles of 3-5 nm in diameter are homogeneously distributed throughout the spheres and none are on the surface. A systematic optimization of reaction parameters results in isolated, porous, and uniform Fe3O4-MnO2 composite spheres. The spheres' average diameter is dependent on the temperature, and thus is controllable in a range of 0.7-1.28 ?m. The involved growth mechanism is discussed. The specific capacitance is optimized at an Fe/Mn atomic ratio of r = 0.075 to be 448 F/g at a scan rate of 5 mV/s, which is nearly 1.5 times that of the extremely high reported value for MnO2 nanostructures (309 F/g). Especially, such a structure allows significantly improved stability at high charging rates. The composite has a capacitance of 367.4 F/g at a high scan rate of 100 mV/s, which is 82% of that at 5 mV/s. Also, it has an excellent cycling performance with a capacitance retention of 76% after 5000 charge/discharge cycles at 5 A/g. PMID:25255299

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

    Science.gov (United States)

    Qin, Huan; Xu, Dong; Yang, Sihua

    2011-01-01

    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.

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

    Science.gov (United States)

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

    2015-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yong Seok Kim

    2014-01-01

    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.

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

    International Nuclear Information System (INIS)

    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.

  1. Tuning the Magnetic Properties in Exchange Coupled FeO/ Fe 3 O 4Core-Shell Nanoparticles

    Science.gov (United States)

    Frey Huls, Natalie; Sun, Xiaolian; Sun, Shouheng; NIST Collaboration; Brown University Collaboration

    2011-03-01

    Chemically synthesized FeO with a native oxide shell has recently received attention due to the large exchange bias effects observed in this system. The magnetic properties reported thus far have been highly dependent upon the aging affects of the system given the vulnerability of FeO to further oxidation resulting in degradation of the exchange bias effects. We report on the magnetic properties of FeO nanoparticles chemically synthesized to form several base diameters (10 nm, 20 nm, and 30 nm) which have each been annealed at various temperatures to obtain a variety of core/shell FeO/ Fe 3 O4 size ratios. This controlled oxidation method has also given excellent chemical stability to the particles. XRD analysis confirms the existence of polycrystalline phases of FeO and Fe 3 O4 , and magnetometry experiments reveal the existence of large exchange bias (up to 230 mT) as well as coercivity enhancements (up of 250 mT) which persist up the Néel temperature (which scales with core size). Other exchange coupling effects such as a large vertical shift in the field cooled hysteresis loops and asymmetric magnetization reversal are observed. Our results further advance the understanding of this exchange coupled system and imply that the properties can be chosen utilizing as-synthesized particle size and annealing temperatures.

  2. Synthesis and characterization of magnetically recyclable Ag nanoparticles immobilized on Fe3O4@C nanospheres with catalytic activity

    Science.gov (United States)

    Li, Wei-hong; Yue, Xiu-ping; Guo, Chang-sheng; Lv, Jia-pei; Liu, Si-si; Zhang, Yuan; Xu, Jian

    2015-04-01

    A novel approach for the synthesis of Ag-loaded Fe3O4@C nanospheres (Ag-Fe3O4@C) was successfully developed. The catalysts possessed a carbon-coated magnetic core and grew active silver nanoparticles on the outer shell using hydrazine monohydrate as the AgNO3 reductant in ethanol. The morphology, inner structure, and magnetic properties of the as-prepared composites were studied with transmission electron microscopy (TEM), X-ray powder diffraction (XRD), fourier translation infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM) techniques. Catalytic activity was investigated by degrading rhodamine B (RhB) in the designed experiment. The obtained products were monodispersed and bifunctional with high magnetization, as well as exhibited excellent catalytic activity toward organic dye with 98% of RhB conversion within 20 min in the presence of NaBH4. The product also exhibited convenient magnetic separability and maintained high catalytic activity after six cycle runs.

  3. 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

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

    Science.gov (United States)

    Dehghani, Z.; Iranizad, E. Saievar

    2014-02-01

    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.

  5. Influence of silver concentrations on structural and magnetic properties of Ag-Fe3O4 heterodimer nanoparticles.

    Science.gov (United States)

    Muraca, D; Sharma, S K; Socolovsky, L M; de Siervo, A; Lopes, G; Pirota, K R

    2012-09-01

    In the present work, we have reported the effect of Ag NPs seeds on the growth and magnetic properties of Ag-Fe3O4 heterodimer nanoparticles prepared using a two step chemical approach. Three different Ag NPs concentrations have been tried and thoroughly characterized using small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), X-ray diffraction (XRD), dc magnetization, and X-ray absorption near edge spectroscopy (XANES). It is observed that at low concentration, the "flower" types of nanoparticles are more favorable whereas the higher concentration of Ag NPs seeds promotes the growth of dimer type of structures. Our dc magnetization results are well correlated to the structural ones. The sample with lower amount of starting Ag NPs seeds possesses highest blocking and irreversibility temperature. On the other hand, the sample with highest concentration of Ag NPs seeds, the blocking temperature is lowered. PMID:23035421

  6. 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)

    Li K

    2013-05-01

    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

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

    Scientific Electronic Library Online (English)

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

    2013-11-15

    Full Text Available 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.

  8. Remoción de pesticidas órgano-fosforados en aguas con nanopartículas magnéticas de Fe3O4 soportadas en sílice / Removal of organophosphorus pesticides in water with supported silica Fe3O4 magnetic nanoparticles

    Scientific Electronic Library Online (English)

    Yosmery, Vitta Brito; Alberto, Fernández Cuervo; Yolanda, Moliner-Martínez; Pilar, Campíns Falco.

    2014-09-01

    Full Text Available En este trabajo se evaluó la eficiencia de Nanopartículas, (Nps), magnéticas de Fe3O4 incorporadas en una matriz de sílice mediante el método sol-gel, como adsorbente de los pesticidas organofosforados: Chlorfenvifos (Chlorf) y Chlorpyrifos (Chlorp) en aguas de efluentes residuales. Las Nps de Fe3O4 [...] -SiO2 presentaron un tamaño promedio de 5 nm. Los límites de detección fueron de 1 ?g L-1 y 2 ?g L-1 para el Chlorf y el Chlorp respectivamente, obteniendo una precisión intradiaria del 2 % e inter-diaria del 3%. La isoterma de adsorción según Langmuir, reportó que el Chlorp fue la especie más adsorbida por el nano-adsorbente con una capacidad máxima de adsorción, Smáx de 0,70 ± 0,35 ?g g-1, mientras que el Chlorf reportó un Smáx de 0,40 ± 0,12 ?g g-1. El procedimiento fue ensayado en aguas residuales, alcanzando una remoción entre el 60 - 85% en los analitos. El mecanismo de adsorción de los pesticidas, se atribuye a la interacción entre estos compuestos apolares y las cadenas alifáticas de las micelas del Bromuro de hexadeciltrimetilamonio, CTAB, del adsorbente, dado que los porcentajes de los analitos en el líquido fueron inferiores al 10%. Abstract in english This paper evaluates the efficiency of Fe3O4 magnetic nanoparticles embedded in silica matrix, by a sol-gel method, as adsorbent of two organophosphate pesticides, Chlorfenvifos (Chlorf) and Chlorpyrifos (Chlorp), in sewage. The Fe3O4- SiO2 Nps have an average size of 5 nm. The detection limits were [...] 1 ? g L-1 for the Chlorf and 2 ? g L-1 for the Chlorp, obtaining an intra-day precision of 2% and inter-day 3%. According to the Langmuir adsorption isotherm, the Chlorp was identified as the more adsorbed species with Smax = de 0.70 ± 0.15 ?g g-1, while Smax = 0.40 ± 0.12 ?g g-1 for Chlorf. The procedure was tested on sewage, reaching analyte’s removal between 60 - 85%. The adsorption mechanism of pesticides is attributed to the hydrophobic interaction between these compounds and aliphatic chains of CTAB micelles, since the percentage of compounds in the liquid was less than 10%.

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

    Science.gov (United States)

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

    2015-02-01

    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.

  10. 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..

  11. One-step synthesis of monodisperse, water-soluble ultra-small Fe3O4 nanoparticles for potential bio-application

    Science.gov (United States)

    Shen, Li-Hua; Bao, Jian-Feng; Wang, Dong; Wang, Yi-Xiao; Chen, Zhi-Wei; Ren, Lei; Zhou, Xi; Ke, Xue-Bin; Chen, Min; Yang, An-Qi

    2013-02-01

    We report that ultra-small, monodisperse, water-dispersible magnetite (Fe3O4) nanoparticles can be synthesized by a facile one-pot approach using trisodium citrate as crystal grain growth inhibitor and stabilizer in polyol solution. The resultant Fe3O4 nanoparticles exhibit an excellent long-term colloidal stability in various buffer solutions without any modification. They are also superparamagnetic at room temperature and their magnetic property relies heavily on their size. Due to the low magnetization and good water-dispersibility, the 1.9 nm-sized Fe3O4 nanoparticles reveal a low r2/r1 ratio of 2.03 (r1 = 1.415 mM-1 s-1, r2 = 2.87 mM-1 s-1), demonstrating that they can be efficient T1 contrast agents. On the other hand, because of the excellent magnetic responsivity, the 13.8 nm-sized Fe3O4 nanoparticles can be readily modified with nitrilotriacetic acid and used to separate the protein simply with the assistance of a magnet. In addition, these Fe3O4 nanoparticles may be useful in other fields, such as hyperthermia treatment of cancer and targeted drug delivery based on their size-dependent magnetic property and excellent stability.

  12. The synthesis and characterization of monodispersed chitosan-coated Fe3O4 nanoparticles via a facile one-step solvothermal process for adsorption of bovine serum albumin

    Science.gov (United States)

    2014-01-01

    Preparation of magnetic nanoparticles coated with chitosan (CS-coated Fe3O4 NPs) in one step by the solvothermal method in the presence of different amounts of added chitosan is reported here. The magnetic property of the obtained magnetic composite nanoparticles was confirmed by X-ray diffraction (XRD) and magnetic measurements (VSM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) allowed the identification of spherical nanoparticles with about 150 nm in average diameter. Characterization of the products by Fourier transform infrared spectroscopy (FTIR) demonstrated that CS-coated Fe3O4 NPs were obtained. Chitosan content in the obtained nanocomposites was estimated by thermogravimetric analysis (TGA). The adsorption properties of the CS-coated Fe3O4 NPs for bovine serum albumin (BSA) were investigated under different concentrations of BSA. Compared with naked Fe3O4 nanoparticles, the CS-coated Fe3O4 NPs showed a higher BSA adsorption capacity (96.5 mg/g) and a fast adsorption rate (45 min) in aqueous solutions. This work demonstrates that the prepared magnetic nanoparticles have promising applications in enzyme and protein immobilization. PMID:24994954

  13. 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.

  14. Two-dimensional magnetic WS2@Fe3O4 nanocomposite with mesoporous silica coating for drug delivery and imaging-guided therapy of cancer.

    Science.gov (United States)

    Yang, Guangbao; Gong, Hua; Liu, Teng; Sun, Xiaoqi; Cheng, Liang; Liu, Zhuang

    2015-08-01

    Integrating multiple imaging and therapy functionalities into one single nanoscale platform has been proposed to be a promising strategy in cancer theranostics. In this work, WS2 nanosheets with their surface pre-adsorbed with iron oxide (IO) nanoparticles via self-assembly are coated with a mesoporous silica shell, on to which polyethylene glycol (PEG) is attached. The obtained WS2-IO@MS-PEG composite nanoparticles exhibit many interesting inherent physical properties, including high near-infrared (NIR) light and X-ray absorbance, as well as strong superparamagnetism. In the mean time, the mesoporous silica shell in WS2-IO@MS-PEG could be loaded with a chemotherapy drug, doxorubicin (DOX), whose intracellular release afterwards may be triggered by NIR-induced photothermal heating for enhanced cancer cell killing. Upon systemic administration of such drug-loaded nano-theranostics, efficient tumor homing of WS2-IO@MS-PEG/DOX is observed in tumor-bearing mice as revealed by three-modal fluorescence, magnetic resonance (MR), and X-ray computed tomography (CT) imaging. In vivo combined photothermal & chemotherapy is then carried out with WS2-IO@MS-PEG/DOX, achieving a remarkably synergistic therapeutic effect superior to the respective mono-therapies. Our study highlights the promise of developing multifunctional nanoscale theranostics based on two-dimensional transition metal dichalcogenides (TMDCs) such as WS2 for multimodal imaging-guided combination therapy of cancer. PMID:25985153

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

    OpenAIRE

    Chittor Raghuraman; Babu Heman; Chockalingam Ashwin; Tiwari Jai

    2010-01-01

    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 i...

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

    OpenAIRE

    Chen, Baoan; Sun, Qian; Wang, Xuemei; GAO, FENG; Dai, Yongyuan; Yin, Yan; Ding, Jiahua; Gao, Chong; Cheng, Jian; Li, Jingyuan; Sun, Xinchen; Chen, Ningna; Xu, Wenlin; SHEN, HUILING; Liu, Delong

    2008-01-01

    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. ...

  17. Shape-dependent microwave permeability of Fe3O4 nanoparticles: a combined experimental and theoretical study.

    Science.gov (United States)

    Yang, Yong; Yang, Yang; Xiao, Wen; Neo, Chye Poh; Ding, Jun

    2015-07-01

    Shape anisotropy is crucial for the microwave permeability of magnetic nanoparticles. In this work, we conduct a systematic study on the shape-dependent microwave permeability of magnetic nanoparticles. Three kinds of Fe3O4 nanoparticles with different geometric shapes (rod, disc, and octahedron) are fabricated by chemical methods and their permeability is investigated through both theoretical calculation and experiment. The results suggest that the rod could exhibit the highest resonance frequency (fr), while the lowest resonance frequency could be found in the octahedron. An opposite trend is observed in the initial permeability (?0). In order to confirm the experimental permeability, we establish an improved LL-G model, which could take both the shape anisotropy and magnetic domain structure into account by introducing a local effective anisotropy field (Heff). The good agreement between the calculated and experimental permeability proves that the model can reproduce shape-dependent microwave permeability of magnetic nanoparticles. More importantly, no fitting process is involved in this model, enabling us to predict the permeability of magnetic nanostructures independent of experiment results. PMID:26059419

  18. 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)

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

    2014-10-15

    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

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

    International Nuclear Information System (INIS)

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

  20. Uniform superparamagnetic Fe3O4 nanoparticles: preparation, characterization and surface modification.

    Czech Academy of Sciences Publication Activity Database

    Patsula, Vitalii; Horák, Daniel

    Prague : Institute of Macromolecular Chemistry AS CR, 2014. P5. ISBN 978-80-85009-79-8. [Workshop "Career in Polymers" /6./. 18.07.2014-19.07.2014, Prague] R&D Projects: GA ?R GAP206/12/0381 Institutional support: RVO:61389013 Keywords : nanoparticles * iron oxide * thermal decomposition Subject RIV: CG - Electrochemistry

  1. Folic acid-conjugated Fe3O4 magnetic nanoparticles for hyperthermia and MRI in vitro and in vivo

    International Nuclear Information System (INIS)

    The folic acid (FA)-conjugated Fe3O4 magnetic nanoparticles (MNPs) were synthesized by co-precipitation of Fe3+ and Fe2+ solution followed by surface modification with carboxymethyl dextran (CMD) to form carboxymethyl group terminated MNPs, then FA was conjugated with the carboxyl group functionalized MNPs. The morphology and properties of obtained nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–visible spectra (UV–vis), transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The FA-conjugated MNPs exhibited relatively high saturation magnetization and fast magneto-temperature response which could be applied to hyperthermia therapy. To determine the accurate targeting effect of FA, we chose FA-conjugated MNPs as MRI contrast enhancement agent for detection of KB cells with folate receptor over-expression in vitro and in vivo. The results show that these magnetic nanoparticles appear to be the promising materials for local hyperthermia and MRI.

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

    Directory of Open Access Journals (Sweden)

    Huining L

    2013-11-01

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

  3. One-step synthesis of water-dispersible cysteine functionalized magnetic Fe3O4 nanoparticles for mercury(II) removal from aqueous solutions

    Science.gov (United States)

    Shen, Xiaofang; Wang, Qin; Chen, WenLing; Pang, Yuehong

    2014-10-01

    Cysteine functionalized Fe3O4 magnetic nanoparticles (Cys-Fe3O4 MNPs) were prepared facilely for Hg(II) removal from aqueous solutions. Using Fe2+ as precursors, air as oxidant and Cys as protectant, this novel material was one-pot synthesis at room temperature by oxidation-precipitation method with the assistance of sonication. The MNPs were characterized by TEM, VSM, FTIR, X-ray powder diffraction analysis (XRD) and TGA methods. Under the optimum experimental conditions, the removal efficiency was as high as 95% and the maximum sorption capacity is found to be 380 mg/mol for Hg(II). Study on adsorption kinetics shows that adsorption of Hg(II) onto Cys-Fe3O4 MNPs follows pseudo-first-order kinetic model and the adsorption rate constant was 0.22 min-1. Additionally, the Hg(II)-loaded Cys-Fe3O4 MNPs could be easily regenerated up to 95% using 1.0 M acetic acid. These results indicated that Cys-Fe3O4 MNPs is a potentially attractive material for the removal of Hg(II) from water.

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Xia G

    2011-09-01

    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

  6. Multifunctional Fe3O4/TaO(x) core/shell nanoparticles for simultaneous magnetic resonance imaging and X-ray computed tomography.

    Science.gov (United States)

    Lee, Nohyun; Cho, Hye Rim; Oh, Myoung Hwan; Lee, Soo Hong; Kim, Kangmin; Kim, Byung Hyo; Shin, Kwangsoo; Ahn, Tae-Young; Choi, Jin Woo; Kim, Young-Woon; Choi, Seung Hong; Hyeon, Taeghwan

    2012-06-27

    Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, a sol-gel reaction of tantalum(V) ethoxide in a microemulsion containing Fe(3)O(4) nanoparticles (NPs) was used to synthesize multifunctional Fe(3)O(4)/TaO(x) core/shell NPs, which were biocompatible and exhibited a prolonged circulation time. When the NPs were intravenously injected, the tumor-associated vessel was observed using computed tomography (CT), and magnetic resonance imaging (MRI) revealed the high and low vascular regions of the tumor. PMID:22676237

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

    Science.gov (United States)

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

    2011-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Wang C

    2011-09-01

    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

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

    Directory of Open Access Journals (Sweden)

    Tingting Gu

    2014-02-01

    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.

  10. Co-adsorption of gaseous benzene, toluene, ethylbenzene, m-xylene (BTEX) and SO2 on recyclable Fe3O4 nanoparticles at 0-101% relative humidities.

    Science.gov (United States)

    Ye, Connie Z; Ariya, Parisa A

    2015-05-01

    We herein used Fe3O4 nanoparticles (NPs) as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and m-xylene (BTEX) and sulfur dioxide (SO2), at different relative humidities (RH). X-ray diffraction, Brunauer-Emmett-Teller, and transmission electron microscopy were deployed for nanoparticle surface characterization. Mono-dispersed Fe3O4 (Fe2O3·FeO) NPs synthesized with oleic acid (OA) as surfactant, and uncoated poly-dispersed Fe3O4 NPs demonstrated comparable removal efficiencies. Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies (up to (95±2)%) under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as a function of the increase in RH, yet, under our experimental conditions, we observed (40±4)% toluene removal at supersaturation for Fe3O4 NPs, and toluene removal of (83±4)% to (59±6)%, for OA-Fe3O4 NPs. In the presence of SO2, the toluene uptake was reduced under dry conditions to (89±2)% and (75±1)% for the uncoated and coated NPs, respectively, depicting competitive adsorption. At RH>100%, competitive adsorption reduced the removal efficiency to (27±1)% for uncoated NPs whereas OA-Fe3O4 NPs exhibited moderate efficiency loss of (55±2)% at supersaturation. Results point to heterogeneous water coverage on the NP surface. The magnetic property of magnetite facilitated the recovery of both types of NPs, without the loss in efficiency when recycled and reused. PMID:25968270

  11. 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)

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

    Directory of Open Access Journals (Sweden)

    Baoan Chen

    2009-03-01

    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

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

    International Nuclear Information System (INIS)

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

  14. 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)

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

    2013-03-15

    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.

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

    Science.gov (United States)

    Chen, Jieping; Zhu, Xiashi

    2015-02-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Baoan Chen

    2008-06-01

    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

  17. 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.

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

    Science.gov (United States)

    Kanimozhi, S.; Perinbam, K.

    2013-04-01

    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.

  19. 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.

  20. Fabrication of Fe3O4 Nanoparticle-coalesced Hydroxylated Multi-walled Carbon Nanotubes for the Analysis of Strychnine in Human Serum.

    Science.gov (United States)

    Feng, Zufei; Xu, Yuehong; Wei, Shuguang; Zhang, Bao; Guan, Fanglin; Li, Shengbin

    2015-01-01

    A magnetic carbon nanomaterial for Fe3O4-modified hydroxylated multi-walled carbon nanotubes (Fe3O4-MWCNTs-OH) was prepared by the aggregating effect of Fe3O4 nanoparticles on MWCNTs-OH, and this material was combined with high-performance liquid chromatography (HPLC)/photodiode array detector (PAD) to determine strychnine in human serum samples. Some important parameters that could influence the extraction efficiency of strychnine were optimized, including the extraction time, amounts of Fe3O4-MWCNTs-OH, pH of sample solution, desorption solvent and desorption time. Under optimal conditions, the recoveries of spiked serum samples were between 98.3 and 102.7%, and the relative standard deviations (RSDs) ranged from 0.9 to 5.3%. The correlation coefficient was 0.9997. The LODs and LOQs of strychnine were 6.2 and 20.5 ng mL(-1), at signal-to-noise ratios of 3 and 10, respectively. These experimental results showed that the proposed method is feasible for the analysis of strychnine in serum samples. PMID:25958869

  1. Core-shell structured Fe3O4@TiO2-doxorubicin nanoparticles for targeted chemo-sonodynamic therapy of cancer.

    Science.gov (United States)

    Shen, Song; Wu, Lin; Liu, Jiejie; Xie, Meng; Shen, Haijun; Qi, Xueyong; Yan, Yongmin; Ge, Yanru; Jin, Yi

    2015-05-30

    To facilitate targeting drug delivery and combined therapy, we develop titanium dioxide-encapsulated Fe3O4 nanoparticles (Fe3O4@TiO2 NPs). Titanium dioxide (TiO2), which is employed as a sonosensitizer for sonodynamic therapy (SDT), can also be used for the loading of doxorubicin (DOX). The fabricated Fe3O4@TiO2 NPs exhibit pH-dependent loading and release of doxorubicin (DOX) in vitro. After incubation with cancer cells, reactive oxygen species (ROS) are generated efficiently upon the irradiation of ultrasound. In the biodistribution experiments, extremely high in vivo tumor accumulation of Fe3O4@TiO2 NPs and long-time retention effect are observed. Compared with chemotherapy or sonodynamic treatment alone, the combined therapy demonstrated a synergistic effect, resulting in stronger cytotoxicity and higher therapeutic efficacy. Thus, the constructed NPs are endowed with multifunctions which allow them to selectively deliver combinatorial therapeutic payload to tumor with enhanced therapeutic effectiveness and minimal side effects. PMID:25841570

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

    Directory of Open Access Journals (Sweden)

    Jia Y

    2012-03-01

    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

  3. 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

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2014-08-01

    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

  6. Synthesis of superparamagnetic silica-coated magnetite nanoparticles for biomedical applications

    Science.gov (United States)

    Kaur, Navjot; Chudasama, Bhupendra

    2015-05-01

    Multifunctional superparamagnetic iron oxide nanoparticles (SPIONs) coated with silica are widely researched for biomedical applications such as magnetic resonance imaging, tissue repair, cell separation, hyperthermia, drug delivery, etc. In this article synthesis of magnetite (Fe3O4) nanoparticles and their coating with SiO2 is reported. Fe3O4 nanoparticles were synthesized by chemical co-precipitation and it was coated with silica by hydrolysis and condensation of tetraethylorthosilicate. XRD, FTIR, TEM and VSM techniques were used to characterize bare and coated nanoparticles. Results indicated that the average size of SPIONS was 8.4 nm. X-ray diffraction patterns of silica coated SPIONS were identical to that of SPIONS confirming the inner spinal structure of SPIONS. FTIR results confirmed the binding of silica with the magnetite and the formation of the silica shell around the magnetite core. Magnetic properties of SPIONS and silica coated SPIONS are determined by VSM. They are superparamagnetic. The major conclusion drawn from this study is that the synthesis route yields stable, non-aggregated magnetite-silica core-shell nanostructures with tailored morphology and excellent magnetic properties.

  7. Anisotropy effects in magnetic hyperthermia: A comparison between spherical and cubic exchange-coupled FeO/Fe3O4 nanoparticles

    Science.gov (United States)

    Khurshid, H.; Alonso, J.; Nemati, Z.; Phan, M. H.; Mukherjee, P.; Fdez-Gubieda, M. L.; Barandiarán, J. M.; Srikanth, H.

    2015-05-01

    Spherical and cubic exchange-coupled FeO/Fe3O4 nanoparticles, with different FeO:Fe3O4 ratios, have been prepared by a thermal decomposition method to probe anisotropy effects on their heating efficiency. X-ray diffraction and transmission electron microscopy reveal that the nanoparticles are composed of FeO and Fe3O4 phases, with an average size of ˜20 nm. Magnetometry and transverse susceptibility measurements show that the effective anisotropy field is 1.5 times larger for the cubes than for the spheres, while the saturation magnetization is 1.5 times larger for the spheres than for the cubes. Hyperthermia experiments evidence higher values of the specific absorption rate (SAR) for the cubes as compared to the spheres (200 vs. 135 W/g at 600 Oe and 310 kHz). These observations point to an important fact that the saturation magnetization is not a sole factor in determining the SAR and the heating efficiency of the magnetic nanoparticles can be improved by tuning their effective anisotropy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-15

    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.

  9. 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.

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

    Directory of Open Access Journals (Sweden)

    Jian Cheng

    2009-09-01

    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

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

    Directory of Open Access Journals (Sweden)

    Bao-an Chen

    2009-09-01

    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

  12. Preparation and properties of Fe and Fe3O4 nanoparticles embedded in ZrO2 matrix

    International Nuclear Information System (INIS)

    The (Zr, ZrO2)-(Fe, Fe3O4) nanocomposites are investigated due to their magnetic properties and resistance against negative influence of the surrounding atmosphere namely at elevated temperatures. The particles of pure Zr and its intermetallic phases can effect as a getter protecting the iron particles against oxidation. We have investigated behaviour of the nanocrystalline powders prepared as a mixture from pure components. TEM and XRD were explored for standard phase composition and determination of the main particle size. Moessbauer spectra were collected by a standard transmission method at room temperature using 57Co/Rh source. Magnetic measurements were carried out using vibrating sample magnetometer at high temperature at (293 - 1093) K, in the vacuum (10-1 Pa) and in the pure hydrogen (5N) atmosphere. The structure study showed that as-prepared samples consist of Fe3O4 particles with the mean coherent length ?30 nm as determined by XRD which increased during the heat treatment up to ?50 - 100 nm. The samples annealed in vacuum were formed by particles of ZrO2-monoclinic, ZrO2-tetragonal and ZrO2-cubic and iron oxide (?-Fe2O3, Fe3O4 and FeO) phases. The annealing in hydrogen caused reduction of iron oxides to pure iron particles and clusters in ZrO2. The magnetic parameters confirm full transformation of iron oxides to bcc iron. (authors)

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

    Directory of Open Access Journals (Sweden)

    Babak Kakavandi

    2013-02-01

    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

  14. Encapsulating Ionic Liquid and Fe3O4 Nanoparticles in Gelatin Microcapsules as Microwave Susceptible Agent for MR Imaging-guided Tumor Thermotherapy.

    Science.gov (United States)

    Du, Qijun; Ma, Tengchuang; Fu, Changhui; Liu, Tianlong; Huang, Zhongbing; Ren, Jun; Shao, Haibo; Xu, Ke; Tang, Fangqiong; Meng, Xianwei

    2015-06-24

    The combination of therapies and monitoring the treatment process has become a new concept in cancer therapy. Herein, gelatin-based microcapsules have been first reported to be used as microwave (MW) susceptible agent and magnetic resonance (MR) imaging contrast agent for cancer MW thermotherapy. Using the simple coacervation methods, ionic liquid (IL) and Fe3O4 nanoparticles (NPs) were wrapped in microcapsules, and these microcapsules showed good heating efficacy in vitro under MW irradiation. The results of cell tests indicated that gelatin/IL@Fe3O4 microcapsules possessed excellent compatibility in physiological environments, and they could effectively kill cancer cells with exposure to MW. The ICR mice bearing H22 tumors treated with gelatin/IL@Fe3O4 microcapsules were obtained an outstanding MW thermotherapy efficacy with 100% tumor elimination under ultralow density irradiation (1.8 W/cm(2), 450 MHz). In addition, the applicability of the microcapsules as an efficient contrast agent for MR imaging in vivo was evident. Therefore, these multifunctional microcapsules have a great potential for MR imaging-guided MW thermotherapy. PMID:26031508

  15. Flow-injection amperometric determination of glucose using a biosensor based on immobilization of glucose oxidase onto Au seeds decorated on core Fe3O4 nanoparticles.

    Science.gov (United States)

    Samphao, Anchalee; Butmee, Preeyanut; Jitcharoen, Juthamas; Švorc, ?ubomír; Raber, Georg; Kalcher, Kurt

    2015-09-01

    An amperometric biosensor based on chemisorption of glucose oxidase (GOx) on Au seeds decorated on magnetic core Fe3O4 nanoparticles (Fe3O4@Au) and their immobilization on screen-printed carbon electrode bulk-modified with manganese oxide (SPCE{MnO2}) was designed for the determination of glucose. The Fe3O4@Au/GOx modified SPCE{MnO2} was used in a flow-injection analysis (FIA) arrangement. The experimental conditions were investigated in amperometric mode with the following optimized parameters: flow rate 1.7mLmin(-1), applied potential +0.38V, phosphate buffer solution (PBS; 0.1molL(-)(1), pH 7.0) as carrier and 3.89 unitmm(-2) enzyme glucose oxidase loading on the active surface of the SPCE. The designed biosensor in FIA arrangement yielded a linear dynamic range for glucose from 0.2 to 9.0mmolL(-1) with a sensitivity of 2.52µAmM(-1)cm(-2), a detection limit of 0.1mmolL(-1) and a quantification limit of 0.3mmolL(-1). Moreover, a good repeatability of 2.8% (number of measurements n=10) and a sufficient reproducibility of 4.0% (number of sensors n=3) were achieved. It was found that the studied system Fe3O4@Au facilitated not only a simpler enzyme immobilization but also provided wider linear range. The practical application of the proposed biosensor for FIA quantification of glucose was tested in glucose sirup samples, honeys and energy drinks with the results in good accordance with those obtained by an optical glucose meter and with the contents declared by the producers. PMID:26003689

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

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    Wang C

    2012-02-01

    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

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

    OpenAIRE

    Ding W; Guo L.

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Bao-an Chen

    2010-06-01

    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

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

    Directory of Open Access Journals (Sweden)

    Zahra Rezay Marand

    2014-09-01

    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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    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

    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.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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06351a

  2. 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.

  3. Preparation of SiO2/(PMMA/Fe3O4) nanoparticles using linolenic acid as crosslink agent for nucleic acid detection using chemiluminescent method.

    Science.gov (United States)

    He, Lei; Li, Zhiyang; Fu, Jing; Wang, Fang; Ma, Chao; Deng, Yan; Shi, Zhiyang; Wang, Hua; He, Nongyue

    2011-03-01

    Usually, magnetic nanoparticles (MNPs) are prepared based on the famous Stöber process in which divinylbenzene (DVA) is often used as a crosslink agent to synthesize SiO2/(PMMA/Fe3O4) nanoparticles. Compared with DVA, linolenic acid (LNA) is innoxious and can polymerize more easily for it has three unsaturated double bonds. In this paper, LNA was used as a new crosslink agent instead of DVA to synthesize the SiO2/(PMMA/Fe3O4) nanoparticles. The results showed that the core-shell structure could be observed obviously. The sizes of nanoparticles with core-shell structure range from 200 to 500 nm. The DNA probes which was immobilized on the surface of MNPs were used to capture the biotin modified complementary sequence of the probe, and the formed complexes were bonded with streptavidin-modified alkaline phosphatase (SA-AP). Finally the chemiluminescent signals were detected by adding 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane (AMPPD) which was the substrate reagent of AP. The specificity and sensitivity of this approach were investigated in this paper. PMID:21449377

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

    Directory of Open Access Journals (Sweden)

    Ding W

    2013-12-01

    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

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

    Science.gov (United States)

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

    2015-03-01

    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

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-11-10

    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

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

    Directory of Open Access Journals (Sweden)

    Huan Liu

    2013-11-01

    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.

  9. 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

  10. Facile approach to suppress ?-Fe2O3 to ?-Fe2O3 phase transition beyond 600 °C in Fe3O4 nanoparticles

    Science.gov (United States)

    Pati, S. S.; Herojit Singh, L.; Mantilla Ochoa, J. C.; Guimarãesa, E. M.; Sales, M. J. A.; Coaquira, J. A. H.; Oliveira, A. C.; Garg, V. K.

    2015-04-01

    Magnetic iron oxide nanoparticles on a zeolite template have been synthesized using wet chemical approach. The average particle size initially decreases from 8.5 to 6 nm (increasing zeolite concentration from 0 to 75 mg) but increases to 11 nm for higher zeolite concentration (100 mg). Room temperature magnetization curves show an initial decrease in saturation magnetization from 62 to 42 emu per gram due to decrease in particle size as well as increase in contribution from nonmagnetic zeolite template. Further increase in zeolite concentration to 100 mg results in a significant increase in saturation magnetization from 42 to 51 emu per gram. Calorimetric studies show a continuous enhancement in ?-Fe2O3 to ?-Fe2O3 phase transition temperature from 590 to 715 °C by increasing the zeolite concentration from 0 to 75 gm. The exothermic peak corresponding to the ?-Fe2O3 to ?-Fe2O3 phase transition has been completely suppressed for nanoparticles prepared in presence of 100 mg of zeolite. Mössbauer spectra of as-synthesized nanoparticles show an increase of superparamagnetic components from 7 to 36% corresponding to increase in zeolite concentration from 0 to 100 mg. Mössbauer spectra of pure Fe3O4 nanoparticles annealed at 500 °C shows formation of pure ?-Fe2O3 phase and Mössbauer spectra of particles prepared in presence of 25 mg shows only 18% of ?-Fe2O3 phase after annealing at 550 °C. Further increase in zeolite concentration to 50 and 75 mg (annealed at 550 °C) leads to pure ?-Fe2O3. Annealing of Fe3O4 nanoparticles prepared in the presence of 100 mg of zeolite at 650 °C shows formation of only 8% ?-Fe2O3 phase. Our results show an easy and effective method to enhance the thermal stability of magnetic iron oxide nanoparticles making it suitable for high temperature applications.

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Roshanak Khandanlou

    2014-10-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Yang C

    2013-04-01

    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

  14. 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.

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

    Science.gov (United States)

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

    2013-06-01

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

  16. Effect of magnetic nanoparticles of Fe3O4 and wogonin on the reversal of multidrug resistance in K562/A02 cell line

    Directory of Open Access Journals (Sweden)

    Cheng J

    2012-06-01

    Full Text Available Jian Cheng,1,* Lin Cheng,1,* Baoan Chen,1,2 Guohua Xia,1 Chong Gao,1 Huihui Song,1 Wen Bao,1 Qinglong Guo,3 Haiwei Zhang,3 Xuemei Wang41Department of Hematology, Key Medical Disciplines of Jiangsu Province, Zhongda Hospital, Medical School of Southeast University, 2Department of Oncology of Southeast University, 3Key Laboratory of Carcinogenesis and Intervention of Jiangsu Province, China Pharmaceutical University, 4State Key Laboratory of Bioelectronics, Southeast University, Nanjing, People's Republic of China *These authors contributed equally to this workBackground: Multidrug resistance is the main obstacle to the efficiency of systemic chemotherapy against hematologic malignancy. This study investigated the reversible effect of the copolymer wogonin and daunorubicin coloaded into Fe3O4 magnetic anoparticles, and the mechanism potentially involved.Methods: The growth inhibition rate of K562/A02 cells was investigated by MTT assay, and apoptosis of cells and the intracellular daunorubicin concentration were detected by flow cytometry. Distribution of nanoparticles taken up by K562/A02 cells was observed under a transmission electron microscope and demonstrated by Prussian blue staining. The transcription level of MDR1 mRNA and expression of P-glycoprotein were determined by reverse transcriptase polymerase chain reaction and Western blotting assay, respectively.Results: The reversible effect of daunorubicin-wogonin magnetic nanoparticles was 8.87-fold that of daunorubicin + wogonin and of daunorubicin magnetic nanoparticles. Transmission electron microscopy and Prussian blue staining revealed that the nanoparticles were located in the endosome vesicles of cytoplasm. Also, the apoptosis rate and accumulation of intracellular daunorubicin in the daunorubicin-wogonin magnetic nanoparticle group were significantly higher than that in the daunorubicin, daunorubicin + wogonin, and daunorubicin magnetic nanoparticle groups. Furthermore, transcription of MDR1 mRNA and expression of P-glycoprotein in K562/A02 cells were significantly downregulated in the daunorubicin-wogonin magnetic nanoparticle group compared with the other groups.Conclusion: These findings suggest that the remarkable effects of the novel daunorubicin-wogonin magnetic nanoparticle formulation on multidrug resistant K562/A02 leukemia cells would be a promising strategy for overcoming multidrug resistance.Keywords: magnetic nanoparticles, Fe3O4, wogonin, multidrug resistance, daunorubicin, P-glycoprotein

  17. Room temperature synthesis of magnetite (Fe3??O4) nanoparticles by a simple reverse co-precipitation method.

    Czech Academy of Sciences Publication Activity Database

    Mahmed, N.; Heczko, Oleg; Söderberg, O.; Hannula, S.-P.

    2011-01-01

    Ro?. 18, ?. 3 (2011), 032020/1-032020/4. ISSN 1757-8981 Institutional research plan: CEZ:AV0Z10100520 Keywords : ferromagnetic nanoparticles * magnetite nanoparticles synthesis * maghemi Subject RIV: BM - Solid Matter Physics ; Magnetism

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

    International Nuclear Information System (INIS)

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

  19. Synthesis of amino-silane modified superparamagnetic Fe3O4 nanoparticles and its application in immobilization of lipase from Pseudomonas fluorescens Lp1

    International Nuclear Information System (INIS)

    Highlights: ? Magnetic nanoparticles were synthesized by chemical co-precipitation method. ? Surface was functionalized with amino-silane and used for lipase immobilization. ? Characterized through TEM, SEM, XRD, FT-IR and VSM analysis. ? The functionalization and immobilization did not affect the magnetite properties. ? The immobilized lipase showed greater functional property than free lipase. - Abstract: Superparamagnetic nanoparticles (Fe3O4–magnetite) were prepared by chemical co-precipitation method and their surface was functionalized with 3-aminopropyltriethoxysilane via silanization reaction to obtain amino functionalized magnetic nanoparticles. The purified lipase from Pseudomonas fluorescens Lp1 was immobilized onto functionalized magnetite using glutaraldehyde as the coupling agent. The characterization of the nanoparticles was done by scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, vibrating sample magnetometry and Fourier transformed infrared spectroscopy. The size of the magnetite was measured about 10–30 nm. The results of characterization study revealed the successful immobilization of lipase on to functionalized magnetite. The saturation magnetization of magnetic nanoparticles was found to be 28.34 emu/g whereas the immobilized magnetic nanoparticle was 17.074 emu/g. The immobilized lipase had greater activity at 50 °C and thermal stability upto 70 °C. It exhibited excellent reusability for 4 cycles and storage stability upto 15 days by retaining 75% of its initial activity

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Roozbeh Hushiarian

    2014-04-01

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

  2. Synthesis and application of strawberry-like Fe3O4-Au nanoparticles as CT-MR dual-modality contrast agents in accurate detection of the progressive liver disease.

    Science.gov (United States)

    Zhao, Hui Y; Liu, Sen; He, Jian; Pan, Chao C; Li, Hui; Zhou, Zheng Y; Ding, Yin; Huo, Da; Hu, Yong

    2015-05-01

    Development of non-invasive assay for the accurate diagnosis of progressive liver diseases (e.g., fatty liver and hepatocellular carcinoma (HCC)) is of great clinical significance and remains to be a big challenge. Herein, we reported the synthesis of strawberry-like Fe3O4-Au hybrid nanoparticles at room temperature that simultaneously exhibited fluorescence, enhanced X-ray attenuation, and magnetic properties. The results of in vitro fluorescence assay showed that the nanoparticles had significant photo-stability and could avoid the endosome degradation in cells. The in vivo imaging of normal mice demonstrated that the Fe3O4-Au nanoparticles provided 34.61-fold contrast enhancement under magnetic resonance (MR) guidance 15 min post the administration. Computed tomography (CT) measurements showed that the highest Hounsfield Unit (HU) was 174 at 30 min post the injection of Fe3O4-Au nanoparticles. In vivo performance of the Fe3O4-Au nanoparticles was further evaluated in rat models bearing three different liver diseases. For the fatty liver model, nearly homogeneous contrast enhancement was observed under both MR (highest contrast ratio 47.33) and CT (from 19 HU to 72 HU) guidances without the occurrences of focal nodules or dysfunction. For the cirrhotic liver and HCC, pronounced enhancement under MR and CT guidance could be seen in liver parenchyma with highlighted lesions after Fe3O4-Au injection. Furthermore, pathological, hematological and biochemical analysis revealed the absence of acute and chronic toxicity, confirming the biocompatibility of our platform for in vivo applications. Collectively, These Fe3O4-Au nanoparticles showed great promise as a candidate for multi-modality bio-imaging. PMID:25771010

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

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

    2014-01-01

    Nanoparticles (NPs) engineered for biomedical applications are meant to be in contact with protein-rich physiological fluids. These proteins are usually adsorbed onto the NP surface, forming a swaddling layer called protein corona that influences cell internalization. We present a study on protein adsorption onto different magnetic NPs (MNPs) when immersed in cell culture medium, and how these changes affect the cellular uptake. Two colloids with magnetite cores of 25 nm, sa...

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

    Czech Academy of Sciences Publication Activity Database

    Sedla?ík, M.; Mou?ka, R.; Kozáková, Z.; Kazantseva, N. E.; Pavlínek, V.; Ku?itka, I.; Kaman, Ond?ej; Peer, Petra

    2013-01-01

    Ro?. 326, january (2013), s. 7-13. ISSN 0304-8853 Grant ostatní: UTB Zlín(CZ) IGA/25/FT/10/D; GA MŠk(CZ) ED2.1.00/03.0111 Institutional support: RVO:67985874 ; RVO:68378271 Keywords : iron oxide * nanoparticle * ferrofluid * hyperthermia * embolization * microwave synthesis * magnetorheology Subject RIV: BK - Fluid Dynamics; BM - Solid Matter Physics ; Magnetism (FZU-D) Impact factor: 2.002, year: 2013

  6. New method for the immobilization of pullulanase onto hybrid magnetic (Fe3O4-?-carrageenan) nanoparticles by electrostatic coupling with pullulanase/chitosan complex.

    Science.gov (United States)

    Long, Jie; Wu, Zhengzong; Li, Xingfei; Xu, Enbo; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2015-04-01

    We present a simple method to immobilize pullulanase onto hybrid magnetic (Fe3O4-?-carrageenan) nanoparticles, involving the in situ synthesis of magnetic carrageenan nanoparticles and the formation of pullulanase/chitosan complex. The complex behavior of pullulanase with chitosan as a function of pH and protein-polysaccharide ratio was studied by turbidimetric titration. Then, the as-prepared immobilized enzymes were characterized by vibrating-sample magnetometer, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffractometer, and thermogravimetric analysis. It was found that the activity retention of immobilized pullulanase and amount of enzyme loaded reached 95.5% and 96.3 mg/g, respectively, under optimal conditions. The immobilized enzyme exhibited great operational stability (retaining approximately 61% residual activity after ten consecutive reuses), demonstrating that enzyme leakage during the catalysis reaction was efficiently reduced. Furthermore, the activity of immobilized pullulanase was significantly (p enzymes retained 45% of their initial activity after 5 h at 60 °C, compared to 21% for the free enzyme. These results indicated that immobilized pullulanase was efficient in terms of catalytic activity and can be applied to continuous starch processing applications in the food industry. PMID:25797694

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

    CERN Document Server

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

    2014-01-01

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

  8. One-step hydrothermal synthesis of highly water-soluble secondary structural Fe3O4 nanoparticles

    International Nuclear Information System (INIS)

    Magnetite nanoparticles (MNPs) were prepared using the ferric acetylacetonate as the sole iron source in a facile hydrothermal route, while poly(acrylic acid) (PAA) was chosen as the stabilizer via one-step functionalized MNPs for better hydrophilic properties. The orthogonal was used in the paper for the experimental parameters optimization, including the solvent, the reaction time, the amount of stabilizer and the presynthesis. The obtained highly water dispersible MNPs with uniform size from about 50 to about 100 nm was individually composed of many monodisperse magnetite crystallites approximately 6 nm in size. And the MNPs show high magnetic properties, whose magnetite content was up to 76.76% and the saturation magnetization was 39.0 emu/g. Later the formation mechanism of MNPs was also discussed. Thus the MNPs proved to be very promising for biomedical applications. - Highlights: ? MNPs are prepared in a low-temperature hydrothermal synthesis procedure. ? Synthesis of MNPs is hybridized with their in situ surface functionalization. ? Each of the secondary structural MNPs is composed of monodisperse primary particles. ? The resulting MNPs show good magnetic properties combining that of primary one. ? The size of MNPs is controllable and the mechanism is elaborated.

  9. Epidermal Growth Factor Receptor Targeted Nuclear Delivery and High Resolution Whole Cell X-Ray Imaging of Fe3O4@TiO2 Nanoparticles in Cancer Cells

    OpenAIRE

    Yuan, Ye; Chen, Si; PAUNESKU, TATJANA; Gleber, Sophie Charlotte; Liu, William C.; Doty, Caroline B.; Mak, Rachel; Deng, Junjing; Jin, Qiaoling; Lai, Barry; Brister, Keith; Flachenecker, Claus; Jacobsen, Chris; Vogt, Stefan; Woloschak, Gayle E

    2013-01-01

    Sequestration within the cytoplasm often limits the efficacy of therapeutic nanoparticles that have specific subcellular targets. To allow for both cellular and subcellular nanoparticle delivery we have created Epidermal Growth Factor Receptor (EGFR) targeted Fe3O4@TiO2 nanoparticles that use the native intracellular trafficking of EGFR to improve internalization and nuclear translocation in EGFR-expressing HeLa cells. While bound to EGFR these nanoparticles do not interfere with the interact...

  10. Synthesis of magnetic alginate beads based on Fe3O4 nanoparticles for the removal of 3-methylindole from aqueous solution using Fenton process.

    Science.gov (United States)

    Hammouda, Samia Ben; Adhoum, Nafaâ; Monser, Lotfi

    2015-08-30

    A novel magnetic heterogeneous catalyst has been developed by incorporation of iron(II) and magnetic functionalized nanoparticles Fe3O4 in alginate beads with the aim of using them in the advanced Fenton oxidation of a malodorous compound (3 methyl-indole: 3-MI). The effects of significant operational parameters such as initial pH, oxidant concentration and catalyst amount were investigated and optimized for a better removal of 3-MI at initial concentration of 20mgL(-1). Besides, the catalyst stability was evaluated according to the iron leached into the aqueous solution. Results revealed that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimized conditions, the magnetic catalyst exhibited a good catalytic performance. Total removal of 3 methyl indole and a remarkable organic mineralization, without significant leaching of iron, were attained within 120min at pH 3.0 by using 0.4gL(-1) of Fe-MABs and 9.8mmolL(-1) of H2O2. The novel magnetic catalyst would be of potential application due to its high efficiency, easy recovery and good structural stability. PMID:25867585

  11. Synthesis, characterization, and comparative gas-sensing properties of Fe2O3 prepared from Fe3O4 and Fe3O4-chitosan

    International Nuclear Information System (INIS)

    Highlights: ? We have demonstrated a facile method to prepare Fe3O4 nanoparticles and chitosan-coated Fe3O4 nanoparticles. ? ?-Fe2O3 sensors prepared from those Fe3O4 materials have been investigated and compared. ? The results show potential application of ?-Fe2O3 for CO sensors in environmental monitoring. - Abstract: In this paper, Fe3O4 and chitosan (CS)-coated Fe3O4 nanoparticles were synthesized via co-precipitation method and subsequent covalent binding of CS onto the surface for functionalization, respectively. Characterization of the crystal structures and morphologies of as-synthesized nanoparticles by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy demonstrated that Fe3O4 had a cubic spinal structure with irregular shapes and average diameters of 10–20 nm. The surface states and magnetic properties of Fe3O4-CS nanoparticles were characterized by Fourier transform infrared spectra and vibrating sample magnetometry. Results showed that Fe3O4-CS nanoparticles possessed super-paramagnetic properties, with saturated magnetization up to 60 emu/g. In addition, Fe3O4 and CS-coated Fe3O4 nanoparticles were used in the fabrication of ?-Fe2O32O3 based gas sensors. Gas sensing measurements revealed that the ?-Fe2O3 gas sensor prepared from Fe3O4-CS had a better response to H2, CO, C2H5OH, and NH3 compared with the device prepared from pristine Fe3O4. Furthermore, the ?-Fe2O3 sensor prepared from Fe3O4-CS nanoparticles exhibited the highest response to CO among the test gases, suggesting that it has great potential for practical applications in environmental monitoring.

  12. Aptamer-conjugated bio-bar-code Au-Fe3O4 nanoparticles as amplification station for electrochemiluminescence detection of tumor cells.

    Science.gov (United States)

    Chen, Min; Bi, Sai; Jia, Xiaoqiang; He, Peng

    2014-07-21

    An electrochemiluminescence (ECL) assay has been developed for highly sensitive and selective detection of tumor cells based on cell-SELEX aptamer-target cell interactions through a cascaded amplification process by using bio-bar-code Au-Fe3O4 as amplification station. Firstly, bio-bar-code toehold-aptamer/DNA primer/Au-Fe3O4 (TA/DP/Au-Fe3O4) nanoconjugates are fabricated with a ratio of 1:10 to efficiently avoid cross-linking reaction and recognize target cells, which are immobilized on the substrate by hybridizing aptamer to capture probe with 18-mer. Through strand displacement reaction (SDR), the TA/DP/Au-Fe3O4 composites further act as the amplification station to initiate rolling circle amplification (RCA). As a result, on the surface of TA/DP/Au-Fe3O4, a large number of Ru(bpy)2(dcbpy)NHS-labeled probes hybridize to RCA products, which are easily trapped by magnetic electrode to perform the magnetic particle-based ECL platform. Under isothermal conditions, this powerful amplification strategy permits detection of Ramos cells as low as 16 cells with an excellent selectivity. Moreover, analysis of Ramos cells in complex samples and whole blood samples further show the great potential of this ultrasensitive approach in clinical application involving cancer cells-related biological processes. PMID:25000857

  13. Synthesis of 1D Fe3O4/P(MBAAm-co-MAA) nanochains as stabilizers for Ag nanoparticles and templates for hollow mesoporous structure, and their applications in catalytic reaction and drug delivery.

    Science.gov (United States)

    Zhang, Wei; Si, Xiaowei; Liu, Bin; Bian, Guomin; Qi, Yonglin; Yang, Xinlin; Li, Chenxi

    2015-10-15

    One-dimensional (1D) magnetic Fe3O4/P(MBAAm-co-MAA) nanochains were prepared by distillation-precipitation polymerization of MBAAm and MAA in the presence of Fe3O4 nanoparticles as building blocks under a magnetic heating stirrer, which played two critical roles: serving as magnetic field to induce the self-assembly of Fe3O4 nanoparticles into 1D nanochains and providing thermal energy to induce the polymerization of MAA and MBAAm on the surface of the Fe3O4 nanoparticles. The thickness of the P(MBAAm-co-MAA) layer can be easily tuned by adjusting the successive polymerization steps. The polymer layer that contained carboxyl groups was used as stabilizers for loading Ag nanoparticles and the reaction locus for deposition of outer silica layer via a sol-gel method in presence of C18TMS as the pore directing agent for tri-layer nanochains. The corresponding hollow mesoporous silica nanochains with movable maghemite cores (?-Fe2O3@mSiO2) were produced after removal of the polymer mid-layer and the alkyl groups of the pore directing agent via calcination of the tri-layer nanochains at high temperature. The Fe3O4/P(MBAAm-co-MAA)/Ag nanochains exhibited a highly catalytic efficiency and well reusable property toward the reduction of nitrophenol. Furthermore, the ?-Fe2O3@mSiO2 nanochains possessed hollow mesoporous structure and high specific surface area (197.2m(2)g(-1)) were used as a drug carrier, which displayed a controlled release property. PMID:26119084

  14. A Study of Fe3O4 Magnetic Nanoparticle RF Heating in Gellan Gum Polymer Under Various Experimental Conditions for Potential Application in Drug Delivery

    Science.gov (United States)

    Marcus, Gabriel E.

    Magnetic nanoparticles (MNPs) have found use in a wide variety of biomedical applications including hyperthermia, imaging and drug delivery. Certain physical properties, such as the ability to generate heat in response to an alternating magnetic field, make these structures ideal for such purposes. This study's objective was to elucidate the mechanisms primarily responsible for RF MNP heating and determine how such processes affect polymer solutions that might be useful in drug delivery. 15-20 nm magnetite (Fe3O4) nanoparticles at 0.2% and 0.5% concentrations were heated with RF fields of different strengths (200 Oe, 400 Oe and 600 Oe) in water and in 0.5% gellan gum solution. Mixing and fan cooling were used in an attempt to improve accuracy of data collection. Specific absorption rate (SAR) values were determined experimentally for each combination of solvent, concentration and field strength. Theoretical calculation of SAR was performed using a model based on linear response theory. Mixing yielded greater precision in experimental determination of SAR while the effects of cooling on this parameter were negligible. Solutions with gellan gum displayed smoother heating over time but no significant changes in SAR values. This was attributed to low polymer concentration and lack of structural phase transition. The LRT model was found to be adequate for calculating SAR at low polymer concentration and was useful in identifying Neel relaxation as the dominant heating process. Heating trials with MNPs in 2% agar confirmed Neel relaxation to be primarily responsible for heat generation in the particles studied.

  15. Study of the Thermodynamics of Chromium(III) and Chromium(VI) Binding to Fe3O4 and MnFe2O4 nanoparticles

    OpenAIRE

    Luther, Steven; Brogfeld, Nathan; Kim, Jisoo; Parsons, J.G.

    2013-01-01

    Removal of chromium(III) or (VI) from aqueous solution was achieved using Fe3O4, and MnFe2O4 nanomaterials. The nanomaterials were synthesized using a precipitation method and characterized using XRD. The size of the nanomaterials was determined to be 22.4 ± 0.9 nm (Fe3O4) and 15.5 ± 0.5 nm (MnFe2O4). The optimal binding pH for chromium(III) and chromium(VI) were pH 6 and pH 3. Isotherm studies were performed, under light and dark conditions, to determine the capacity of the nanomaterials. Th...

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

    International Nuclear Information System (INIS)

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

  17. Chitosan and O-carboxymethyl chitosan modified Fe3O4 for hyperthermic treatment

    International Nuclear Information System (INIS)

    In this study magnetic fluids were manufactured by the adsorption of chitosan (CS) and O-carboxymethyl chitosan (OCMCS) on Fe3O4 nanoparticles to be used as hyperthermic thermoseeds. Fe3O4 particles were characterized by physico-chemical methods such as: thermogravimetry analysis (TGA), x-ray diffraction (XRD), Raman spectrum, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The SEM images and XRD patterns showed that the synthesized Fe3O4 nanoparticles were of single phase and spherical shape with 10–15?nm in diameter. The VSM measurements showed that Fe3O4 particles were superparamagnetic with saturation magnetization of 70?emu?g?1. The adsorbed layers of CS and OCMCS on the magnetite surface (Fe3O4/CS) and (Fe3O4/OCMCS) were confirmed by FTIR, Raman spectra and SEM. In the ac magnetic field of 80?Oe and 236?kHz, the saturation heating temperatures of the sample Fe3O4/CS and Fe3O4/OCMCS were 100 and 98?°C, respectively. At the same concentration of Fe3O4 nanoparticles in suspension, the two magnetic fluids exhibited quite high heating capacity, with different behaviors of concentration dependence. The Fe3O4/CS and Fe3O4/OCMCS nanoparticles would serve as good thermoseeds for localized hyperthermia treatment of cancers

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  20. Effect of colloidal ?-cyclodextrins-Fe3 O4 magnetic nanoparticles on the chemiluminescence enhancement of luminol-Ag(III) complex for rapid and sensitive determination of cysteine in human serum.

    Science.gov (United States)

    Rezaei, B; Ensafi, A A; Zarei, L; Kameli, P

    2012-01-01

    Colloidals solution of Fe3 O4 magnetic nanoparticles (MNPs), capped with ?-cyclodextrins (?-CD) as inclusion complexes, were found to enhance the chemiluminescence (CL) intensity of the luminol-diperiodatoargentate(III) (DPA) system. On injection of cysteine into the luminol-DPA-?-CD-Fe3 O4 MNPs inclusion complexes system, the CL intensity is strongly enhanced. The enhanced CL signal is ascribed to the catalytic effect of Fe3 O4 MNPs capped with ?-CD, which is assumed to stabilize the CL intermediate. Based on these findings, a rapid and sensitive assay was developed for the determination of cysteine in human serum. The effects of analytical variables on the CL signal were studied and optimized. Under the optimum conditions, the CL intensity was directly proportional to the concentration of cysteine in the range 8.0?×?10(-9) -1.0?×?10(-6) ?mol/L. The detection limit was 2.8?×?10(-9) ?mol/L (3 S(b) /m) and the relative standard deviation (RSD) for 10 replicate determinations of 1.0?×?10(-7) ?mol/L cysteine was 3.5%. The proposed method was applied to the sensitive determination of cysteine in human serum samples, and compared with the Ellman method with satisfactory results. PMID:22025250

  1. Combined tween 20-stabilized gold nanoparticles and reduced graphite oxide-Fe3O4 nanoparticle composites for rapid and efficient removal of mercury species from a complex matrix.

    Science.gov (United States)

    Shih, Ya-Chen; Ke, Chen-Yi; Yu, Cheng-Ju; Lu, Chi-Yu; Tseng, Wei-Lung

    2014-10-22

    This study describes a simple method for removing mercuric ions (Hg(2+)) from a high-salt matrix based on the use of Tween-20-stabilized gold nanoparticles (Tween 20-Au NPs) as Hg(2+) adsorbents and composites of reduced graphite oxide and Fe3O4 NPs as NP collectors. Citrate ions adsorbed on the surface of the Tween 20-Au NPs reduced Hg(2+) to Hg(0), resulting in the deposition of Hg(0) on the surface of the NPs. To circumvent time-consuming centrifugation and transfer steps, the Hg(0)-containing gold NPs were collected using reduced graphite oxide-Fe3O4 NP composites. Compared with the reported NP-based methods for removing Hg(2+), Tween 20-Au NPs offered the rapid (within 30 min), efficient (>99% elimination efficiency), durable (>10 cycles), and selective removal of Hg(2+), CH3Hg(+), and C2H5Hg(+) in a high-salt matrix without the interference of other metal ions. This was attributed to the fact that the dispersed Tween 20-Au NPs exhibited large surface-area-to-volume ratio to bind Hg(2+) through Hg(2+)-Au(+) metallophilic interactions in a high-salt matrix. The formation of graphite oxide sheets and reduced graphite oxide-Fe3O4 NP composites was demonstrated using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectrometry, and transmission electron microscopy. The mechanism of interaction between Tween 20-Au NPs and Hg(2+) was studied using visible spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. PMID:25238563

  2. Fabrication and characterization of superparamagnetic and thermoresponsive hydrogels based on oleic-acid-coated Fe3O4 nanoparticles, hexa(ethylene glycol) methyl ether methacrylate and 2-(acetoacetoxy)ethyl methacrylate

    International Nuclear Information System (INIS)

    Stimuli-responsive hydrogel nanocomposites comprised of swollen polymer networks, in which magnetic nanoparticles are embedded, are a relatively new class of 'smart' soft materials presenting a significant impact on various technological and biomedical applications. A novel approach for the fabrication of hydrogel nanocomposites exhibiting temperature- and magneto-responsive behavior involves the random copolymerization of hexa(ethylene glycol) methyl ether methacrylate (HEGMA, hydrophilic, thermoresponsive) and 2-(acetoacetoxy)ethyl methacrylate (AEMA, hydrophobic, metal-chelating) in the presence of preformed oleic-acid-coated magnetite nanoparticles (OA.Fe3O4). In total, two series of hydrogel nanocomposites have been prepared in two different solvent systems: ethyl acetate (series A) and tetrahydrofuran (series B). The degrees of swelling (DSs) of all conetworks were determined in organic and in aqueous media. The nanocrystalline phase adopted by the embedded magnetic nanoparticles was investigated by X-ray diffraction (XRD) spectroscopy. The obtained diffraction patterns indicated the presence of magnetite (Fe3O4). Deswelling kinetic studies that were carried out at ?60 oC in water demonstrated the thermoresponsive properties of the hydrogel nanocomposites, attributed to the presence of the hexaethylene glycol side chains within the conetworks. Moreover, thermal gravimetric analysis (TGA) measurements showemetric analysis (TGA) measurements showed that these materials exhibited superior thermal stability compared to the pristine hydrogels. Further to the characterization of compositional and thermal properties, the assessment of magnetic characteristics by vibrational sample magnetometry (VSM) disclosed superparamagnetic behavior. The tunable superparamagnetic behavior exhibited by these materials depending on the amount of magnetic nanoparticles incorporated within the networks combined with their thermoresponsive properties may allow for their future exploitation in the biomedical field. - Research Highlights: ? Fabrication of novel, dual stimuli-responsive conetworks based on hexa(ethylene glycol) methyl ether methacrylate (HEGMA, hydrophilic, thermoresponsive), 2-(acetoacetoxy)ethyl methacrylate (AEMA, hydrophobic, metal-chelating) and oleic-acid-coated magnetite nanoparticles (OA.Fe3O4). ? Tuneable superparamagnetic behavior. ? Thermoresponsive properties.

  3. 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

    Science.gov (United States)

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

    2013-01-01

    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), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor. PMID:23685872

  4. 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

    Directory of Open Access Journals (Sweden)

    Ning Gan

    2013-05-01

    Full Text Available 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, which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2 to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA. The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor.

  5. Poly (vinyl alcohol)/gum karaya electrospun plasma treated membrane for the removal of nanoparticles (Au, Ag, Pt, CuO and Fe3O4) from aqueous solutions.

    Science.gov (United States)

    Padil, Vinod Vellora Thekkae; ?erník, Miroslav

    2015-04-28

    In the present work, nanofibre membranes composed of polyvinyl alcohol (PVA) and a natural gum karaya (GK) hydrocolloid were prepared using electrospinning. The electrospun membranes of PVA/GK were cross-linked with heat treatment and later methane plasma was used to obtain a hydrophobic membrane. The morphology, characterization and adsorption ability of P-NFM was assessed using scanning electron microscopy, UV-vis spectroscopy, ATR-FTIR techniques, water contact angle and ICP-MS analytical methods. The membrane was employed for the extraction of nanoparticles (Ag, Au, Pt, CuO and Fe3O4) from water. The nanoparticle extraction kinetic and adsorption isotherm perform the pseudo-second-order model and Langmuir isotherm model, respectively. The adsorption capacities of the membrane for the removal of NPs from water diverge in the order Pt>Au>Ag>CuO>Fe3O4. The high adsorption efficiency for the removal of NPs from water was compared with an untreated membrane. Physisorption, functional group interactions, complexation reactions between metal/metal oxide nanoparticles with various functional groups present in NFM and modified surface properties such as the balance of hydrophilicity/hydrophobicity, surface free energy, and the high surface area of the plasma treated membrane were possible mechanisms of NPs adsorption onto NFM. The regeneration and reusability were tested in five consecutive adsorption/desorption cycles. PMID:25636139

  6. Hierarchical MWCNTs/Fe3O4/PANI magnetic composite as adsorbent for methyl orange removal.

    Science.gov (United States)

    Zhao, Ying; Chen, Hongli; Li, Jie; Chen, Changlun

    2015-07-15

    Multi-wall carbon nanotubes (MWCNTs) decorated with Fe3O4 nanoparticles (MWCNTs/Fe3O4) were modified by polyaniline (PANI). The adsorption kinetics of methyl orange (MO) on MWCNTs/Fe3O4/PANI could be fitted well by the pseudo-second-order model. The adsorption of MO on MWCNTs/Fe3O4/PANI was strongly dependent on pH values. The Langmuir isotherm model fitted MO adsorption isotherm better than the Freundlich model. The hierarchical MWCNTs/Fe3O4/PANI showed high adsorption capacity toward ionic dyes (446.25mgg(-1) for MO and 417.38mgg(-1) for Congo red (CR)). The nitrogen-containing functional groups of PANI decorated on MWCNTs/Fe3O4/PANI contributed to many effective adsorption sites and thus increased the adsorption capacity toward MO and CR. Moreover, PANI prevented Fe3O4 nanoparticles from dissolution, and hence improved the stability of MWCNTs/Fe3O4/PANI in solution. The experimental results showed that the MWCNTs/Fe3O4/PANI composite was a promising magnetic material for the preconcentration and separation of ionic dye pollutants from aqueous solutions in environmental pollution cleanup. PMID:25819003

  7. Inducing cell cycle arrest and apoptosis by dimercaptosuccinic acid modified Fe3O4 magnetic nanoparticles combined with nontoxic concentration of bortezomib and gambogic acid in RPMI-8226 cells

    Science.gov (United States)

    Zhang, Wei; Qiao, Lixing; Wang, Xinchao; Senthilkumar, Ravichandran; Wang, Fei; Chen, Baoan

    2015-01-01

    The purpose of this study was to determine the potential benefits of combination therapy using dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4) magnetic nanoparticles (MNPs) combined with nontoxic concentration of bortezomib (BTZ) and gambogic acid (GA) on multiple myeloma (MM) RPMI-8226 cells and possible underlying mechanisms. The effects of BTZ-GA-loaded MNP-Fe3O4 (BTZ-GA/MNPs) on cell proliferation were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,4,-diphenyltetrazolium bromide (MTT) method. Cell cycle and apoptosis were detected using the terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling (TUNEL) assay and flow cytometry (FCM). Furthermore, DMSA-Fe3O4 MNPs were characterized in terms of distribution, apoptotic morphology, and cellular uptake by transmission electron microscopy (TEM) and 4,6-diamidino-2-phenylindole (DAPI) staining. Subsequently, the effect of BTZ-GA/MNPs combination on PI3K/Akt activation and apoptotic-related protein were appraised by Western blotting. MTT assay and hematoxylin and eosin (HE) staining were applied to elevate the functions of BTZ-GA/MNPs combination on the tumor xenograft model and tumor necrosis. The results of this study revealed that the majority of MNPs were quasi-spherical and the MNPs taken up by cells were located in the endosome vesicles of cytoplasm. Nontoxic concentration of BTZ-GA/MNPs increased G2/M phase cell cycle arrest and induced apoptosis in RPMI-8226 cells. Furthermore, the combination of BTZ-GA/MNPs activated phosphorylated Akt levels, Caspase-3, and Bax expression, and down-regulated the PI3K and Bcl-2 levels significantly. Meanwhile, the in vivo tumor xenograft model indicated that the treatment of BTZ-GA/MNPs decreased the tumor growth and volume and induced cell apoptosis and necrosis. These findings suggest that chemotherapeutic agents polymerized MNPs-Fe3O4 with GA could serve as a better alternative for targeted therapeutic approaches to treat multiple myeloma. PMID:25995634

  8. Vanillin-molecularly targeted extraction of stir bar based on magnetic field induced self-assembly of multifunctional Fe3O4@Polyaniline nanoparticles for detection of vanilla-flavor enhancers in infant milk powders.

    Science.gov (United States)

    Wu, Jinhua; Yang, Zaiyue; Chen, Ning; Zhu, Wanying; Hong, Junli; Huang, Changgao; Zhou, Xuemin

    2015-03-15

    A molecularly imprinted stir bar was constructed based on Fe3O4@Polyaniline nanoparticles with magnetic field-induced self-assembly process. The monomer, methacrylic acid, was pre-assembled into the pre-polymers with vanillin as template by the formation of hydrogen bonds. After that, the magnetic complexes were generated by the hydrogen bonding, the hydrophobic and ?-? interaction between the pre-polymers and Fe3O4@Polyaniline. The complexes were adsorbed on the surface of magnetic stir bar under the magnetic induction, and the coating of vanillin-molecularly imprinted polymers was generated by the one-step copolymerization basing on the cross linking of ethylene glycol dimethacrylate. The molecular imprinting stir bar showed superior selectivity and fast binding kinetics for vanillin, and was used for the enrichment of vanilla-flavor enhancers (vanillin, ethyl maltol and methyl vanillin) in infant milk powders. The results measured by HPLC-UV exhibited good linear ranges of 0.01-100, 0.02-100 and 0.03-100?gmL(-1) with the limit of detection of 2.5-10.0ngmL(-1), and the recoveries were 94.7-98.9%, 82.1-96.7% and 84.5-93.2% with RSD<7.2% for the three enhancers, respectively. PMID:25514645

  9. Fluorescence analysis of 6-mercaptopurine with the use of a nano-composite consisting of BSA-capped Au nano-clusters and core-shell Fe3O4-SiO2 nanoparticles.

    Science.gov (United States)

    Li, Zhuo; Wang, Yong; Ni, Yongnian; Kokot, Serge

    2015-08-15

    A magnetic and fluorescent nano-composite was prepared. It comprised of a core of Fe3O4 nanoparticles (NPs), a silica shell and satellitic Au nano-clusters (AuNCs) capped with bovine serum albumin (BSA). This nano-composite has many desirable properties, e.g. magnetism, red emission, high water solubility, and high resistance to photo-bleaching. On addition of the analyte, 6-mercaptopurine (6-MP) or indeed other similar thiols, AuNCs formed aggregates because the existing cross-links within the Fe3O4 NPs@SiO2 and AuNC structure were broken in favor of the gold-thiol bonds. On suitable irradiation of such aggregates, red fluorescence was emitted at 613nm. It decreased significantly as a function of the added 6-MP concentration, and the quenching ratio (F0 - F) / F0 was related linearly to the concentration of 6-MP in the range of 0.01 to 0.5?molL(-1). The detection limit was 0.004?molL(-1) (S/N=3). The method was strongly selective for 6-MP in the presence of oxidants, phenols, heavy-metal ions, and especially bio-thiols. PMID:25829222

  10. Terbium doped SnO2 nanoparticles as white emitters and SnO2:5Tb/Fe3O4 magnetic luminescent nanohybrids for hyperthermia application and biocompatibility with HeLa cancer cells.

    Science.gov (United States)

    Singh, Laishram Priyobarta; Singh, Ningthoujam Premananda; Srivastava, Sri Krishna

    2015-03-24

    SnO2:5Tb (SnO2 doped with 5 at% Tb(3+)) nanoparticles were synthesised by a polyol method and their luminescence properties at different annealing temperatures were studied. Characterization of nanomaterials was done by X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). XRD studies indicate that the prepared nanoparticles were of tetragonal structures. Upon Tb(3+) ion incorporation into SnO2, Sn(4+) changes to Sn(2+) and, on annealing again at higher temperature, Sn(2+) changes to Sn(4+). The prepared nanoparticles were spherical in shape. Sn-O vibrations were found from the FTIR studies. In photoluminescence studies, the intensity of the emission peaks of Tb(3+) ions increases with the increase of annealing temperature, and emission spectra lie in the region of white emission in the CIE diagram. CCT calculations show that the SnO2:5Tb emission lies in cold white emission. Quantum yields up to 38% can be obtained for 900 °C annealed samples. SnO2:5Tb nanoparticles were well incorporated into the PVA polymer and such a material incorporated into the polymer can be used for display devices. The SnO2:5Tb/Fe3O4 nanohybrid was prepared and investigated for hyperthermia applications at different concentrations of the nanohybrid. This achieves a hyperthermia temperature (42 °C) under an AC magnetic field. The hybrid nanomaterial SnO2:5Tb/Fe3O4 was found to exhibit biocompatibility with HeLa cells (human cervical cancer cells) at concentrations up to 74% for 100 ?g L(-1). Also, this nanohybrid shows green emission and thus it will be helpful in tracing magnetic nanoparticles through optical imaging in vivo and in vitro application. PMID:25747103

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

    International Nuclear Information System (INIS)

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

  12. Inducing cell cycle arrest and apoptosis by dimercaptosuccinic acid modified Fe3O4 magnetic nanoparticles combined with nontoxic concentration of bortezomib and gambogic acid in RPMI-8226 cells

    Directory of Open Access Journals (Sweden)

    Zhang W

    2015-04-01

    Full Text Available Wei Zhang,1* Lixing Qiao,2* Xinchao Wang,3* Ravichandran Senthilkumar,1 Fei Wang,1 Baoan Chen1,4 1Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Pediatrics, Zhongda Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China; 3Department of Thyroid and Breast, the Fourth Central Hospital, Tianjin, People’s Republic of China; 4Department of Hematology and Oncology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People’s Republic of China *These authors contributed equally to this work Abstract: The purpose of this study was to determine the potential benefits of combination therapy using dimercaptosuccinic acid modified iron oxide (DMSA-Fe3O4 magnetic nanoparticles (MNPs combined with nontoxic concentration of bortezomib (BTZ and gambogic acid (GA on multiple myeloma (MM RPMI-8226 cells and possible underlying mechanisms. The effects of BTZ-GA-loaded MNP-Fe3O4 (BTZ-GA/MNPs on cell proliferation were assessed by the 3-(4,5-dimethylthiazol-2-yl-2,4,-diphenyltetrazolium bromide (MTT method. Cell cycle and apoptosis were detected using the terminal deoxyribonucleotidyl transferase (TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL assay and flow cytometry (FCM. Furthermore, DMSA-Fe3O4 MNPs were characterized in terms of distribution, apoptotic morphology, and cellular uptake by transmission electron microscopy (TEM and 4,6-diamidino-2-phenylindole (DAPI staining. Subsequently, the effect of BTZ-GA/MNPs combination on PI3K/Akt activation and apoptotic-related protein were appraised by Western blotting. MTT assay and hematoxylin and eosin (HE staining were applied to elevate the functions of BTZ-GA/MNPs combination on the tumor xenograft model and tumor necrosis. The results of this study revealed that the majority of MNPs were quasi-spherical and the MNPs taken up by cells were located in the endosome vesicles of cytoplasm. Nontoxic concentration of BTZ-GA/MNPs increased G2/M phase cell cycle arrest and induced apoptosis in RPMI-8226 cells. Furthermore, the combination of BTZ-GA/MNPs activated phosphorylated Akt levels, Caspase-3, and Bax expression, and down-regulated the PI3K and Bcl-2 levels significantly. Meanwhile, the in vivo tumor xenograft model indicated that the treatment of BTZ-GA/MNPs decreased the tumor growth and volume and induced cell apoptosis and necrosis. These findings suggest that chemotherapeutic agents polymerized MNPs-Fe3O4 with GA could serve as a better alternative for targeted therapeutic approaches to treat multiple myeloma. Keywords: magnetic nanoparticles, DMSA-Fe3O4, bortezomib, gambogic acid, PI3K/Akt, cell cycle, apoptosis

  13. The synthesis and characterization of electrical and magnetic nanocomposite: PEDOT/PSS-Fe3O4

    International Nuclear Information System (INIS)

    The poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)-Fe3O4 (PEDOT/PSS-Fe3O4) nanoparticles have been prepared by using polystyrene sulfonic sodium (NaPSS) as a dispersant and dopant. The characterization of nanocomposites was investigated by transmission electron microscope, X-ray diffraction, UV spectroscopy, electrochemical study, four-probe, thermogravimetric analysis and magnetic property measurement system. XRD revealed the presence of spinel phase of Fe3O4 and the average size was calculated to be about 12 nm. The conductivity of nanocomposites at room temperature is excellent and it depends on the Fe3O4 content. The thermal stability of composites is outstanding. Higher saturation magnetization of 6.47 emu g-1 (20 wt.% Fe3O4) was observed at 300 K.

  14. Toxicity Assessment of Silica Coated Iron Oxide Nanoparticles and Biocompatibility Improvement by Surface Engineering

    OpenAIRE

    Malvindi, Maria Ada; Matteis, Valeria; Galeone, Antonio; Brunetti, Virgilio; Anyfantis, George C.; Athanassiou, Athanassia; Cingolani, Roberto; Pompa, Pier Paolo

    2014-01-01

    We have studied in vitro toxicity of iron oxide nanoparticles (NPs) coated with a thin silica shell (Fe3O4/SiO2 NPs) on A549 and HeLa cells. We compared bare and surface passivated Fe3O4/SiO2 NPs to evaluate the effects of the coating on the particle stability and toxicity. NPs cytotoxicity was investigated by cell viability, membrane integrity, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) assays, and their genotoxicity by comet assay. Our results show that NPs surfac...

  15. Electrochemical determination of NADH using a glassy carbon electrode modified with Fe3O4 nanoparticles and poly-2,6-pyridinedicarboxylic acid, and its application to the determination of antioxidant capacity

    International Nuclear Information System (INIS)

    We have prepared a glassy carbon electrode modified with poly-2,6-pyridinedicarboxylic acid and with magnetic Fe3O4 nanoparticles. This modification enhances the effective surface area and the electrocatalytic oxidation of nicotinamide adenine dinucleotide (NADH) in addition to providing positively charged groups for electrostatic assembly of the phosphate group of NADH. The modified electrode responds linearly to NADH in the range from 5 x 10-8 to 2.5 x 10-5 M and gives a lower detection limit of 1 x 10-8 M. It displays satisfactory selectivity and reproducibility. The sensor was applied to rapid screening of plant extracts for their antioxidant properties. (author)

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

    OpenAIRE

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

    2014-01-01

    Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and e...

  17. Sandwich-Structured Graphene-Fe3O4@Carbon Nanocomposites for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Zhao, Li; Gao, Miaomiao; Yue, Wenbo; Jiang, Yang; Wang, Yuan; Ren, Yu; Hu, Fengqin

    2015-05-13

    Advanced anode materials for high power and high energy lithium-ion batteries have attracted great interest due to the increasing demand for energy conversion and storage devices. Metal oxides (e.g., Fe3O4) usually possess high theoretical capacities, but poor electrochemical performances owing to their severe volume change and poor electronic conductivity during cycles. In this work, we develop a self-assembly approach for the synthesis of sandwich-structured graphene-Fe3O4@carbon composite, in which Fe3O4 nanoparticles with carbon layers are immobilized between the layers of graphene nanosheets. Compared to Fe3O4@carbon and bulk Fe3O4, graphene-Fe3O4@carbon composite shows superior electrochemical performance, including higher reversible capacity, better cycle and rate performances, which may be attributed to the sandwich structure of the composite, the nanosized Fe3O4, and the carbon layers on the surface of Fe3O4. Moreover, compared to the reported graphene-Fe3O4 composite, the particle size of Fe3O4 is controllable and the content of Fe3O4 in this composite can be arbitrarily adjusted for optimal performance. This novel synthesis strategy may be employed in other sandwich-structured nanocomposites design for high-performance lithium-ion batteries and other electrochemical devices. PMID:25886399

  18. Controllable Fe3O4/Au substrate for surface-enhanced infrared absorption spectroscopy

    Science.gov (United States)

    Cai, Qian; Hu, Fei; Lee, Shuit-Tong; Liao, Fan; Li, Yanqing; Shao, Mingwang

    2015-01-01

    In this paper, the Fe3O4/Au nanocomposites were fabricated and employed as surface-enhanced infrared absorption (SEIRA) substrates. The superparamagnetic nature of Fe3O4/Au nanocomposites makes them suitable for controlled magnetic manipulation. The infrared absorption enhancements of Fe3O4/Au composite were improved as the magnetic field intensity increasing both for mercaptobenzoic acid and nitrobenzoic acid probe molecules. When the magnetic field intensities increase to 280 mT, the infrared enhancement could raise up to 3.3 and 10.7 times for -SH and -NO2 groups, respectively. The enhancement is due to the synergy of localized surface plasmon resonance of Au and the magnetism of Fe3O4. Under the strong magnetic field, the superparamagnetic Fe3O4/Au nanoparticles are highly concentrated, leading to the increase number of SEIRA "active sites" and the surface density of Au nanoparticles. The synergistic effects of both Fe3O4 and Au nanoparticles make the composites an excellent SEIRA substrate. In addition, the Fe3O4/Au nanocomposites were also utilized to determine the thiol and thione tautomers in -SH based molecules.

  19. Fabrication of fluorescent magnetic Fe3O4@ZnS nanocomposites.

    Science.gov (United States)

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

    2014-07-01

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

  20. Synthesis of Fe3O4@CoFe2O4@MnFe2O4 trimagnetic core/shell/shell nanoparticles

    OpenAIRE

    Gavrilov-Isaac, Véronica; Neveu, Sophie; Dupuis, Vincent; Talbot, Delphine; Cabuil, Valérie

    2014-01-01

    We report the synthesis and characterization of original 'multishell' magnetic nanoparticles made of a soft core (magnetite) covered with two successive shells: a hard one (cobalt ferrite) and then a soft one (manganese ferrite). Our results show that contrary to expectations from simple models in which the coercivity of a bimagnetic core/shell nanoparticle depends simply on the proportion of soft and hard phases within that particle, the addition of a second shell made of a...

  1. Hollow Fe3O4 microspheres as anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

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

  2. Synthesis and characterization of magnetic nanocomposites with Fe3O4 core

    International Nuclear Information System (INIS)

    To improve the infrared absorbing performance of the ferrite magnetic material which has good electromagnetic wave absorbing performance, the core-shell structured multilayer coating is introduced to achieve multiple wavelength range absorbing. Nanocomposites Fe3O4/SiO2/Al2O3 and Fe3O4/SiO2/TiO2 have been prepared using a series of chemical methods. The results of TEM and XRD analysis show that multilayer coated structures exit in both Fe3O4/SiO2/Al2O3 and Fe3O4/SiO2/TiO2 and that the core-double shell particles are all in nano-scale. The saturation magnetization and the coercivity of Fe3O4 at room temperature are 72 A·m2/kg and 3.82 kA/m, respectively. Further coating of SiO2 and Al2O3 or TiO2 decreases the saturation magnetization and the coercivity while all nanocomposites remain ferromagnetic. There is no obvious improvement of the infrared absorbing ability of Fe3O4 nanoparticles in coating of SiO2 while further coating of Al2O3 or TiO2 reduces the infrared emissivity from 0.97 of Fe3O4 nanoparticles to about 0.83 of the core-double shell nanocomposites.

  3. Fe3O4@graphene oxide composite: A magnetically separable and efficient catalyst for the reduction of nitroarenes

    International Nuclear Information System (INIS)

    Highlights: ? The Fe3O4@GO composite was prepared by a facile co-precipitation method. ? Fe3O4 nanoparticles are well distributed on GO nanosheets. ? Fe3O4@GO was for the first time explored as a catalyst to reduce nitroarenes. ? Fe3O4@GO exhibits higher catalytic activity. ? The composite catalyst is easily recycled due to its magnetic separability. - Abstract: We reported a facile co-precipitation method to prepare a highly active Fe3O4@graphene oxide (Fe3O4@GO) composite catalyst, which was fully characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and N2 adsorption–desorption measurements. The results demonstrated that the Fe3O4 nanoparticles (Fe3O4 NPs) with a small diameter of around 12 nm were densely and evenly deposited on the graphene oxide (GO) sheets. The as-prepared Fe3O4@GO composite was explored as a catalyst to reduce a series of nitroarenes for the first time, which exhibited a great activity with a turnover frequency (TOF) of 3.63 min?1, forty five times that of the commercial Fe3O4 NPs. The dosages of catalyst and hydrazine hydrate are both less than those reported. Furthermore, the composite catalyst can be easily recovered due to its magnetic separability and high stability

  4. NOVEL SYNTHESIS OF PEG COATED IRON NANOPARTICLES (Fe3O4 AND IT’S EVALUATION OF CONTROLLED RELEASE KINETICS IN DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    Doppalapudi Swathi

    2014-06-01

    Full Text Available Magnetic Nanoparticles (MNPs because of their high magnetic responsiveness, biodegradability, high delivery efficiency and potential targeting function is a possible material as drug delivery system, since drug –loaded MNPs can be directly injected in to solid tumors and are expected to be held in place by an external magnetic field and to release the drug in a controlled manner. In the present research study Synthesis, Characterization and in vitro rate studies of super paramagnetic Iron Nanoparticles coated with PEG has been carried out. The nanoparticle synthesized in the present study had an average particle size of ~ 30 nm. starch-based polysaccharide nanocarrier encapsulated with the drug i.e. THC and MNPs as anticancer drug delivery was constructed. This efficiently reduces tumor growth thus providing a proof of concept for the utilization of this formulation in cannabinoid-based anti-cancer therapies. Evaluation of THC loaded magnetic nanoparticles was successfully carried out and correlation coefficient (R2 value 0.999 and drug released was found to be 97% for 48hrs at pH7.0. The entrapment efficiency and drug loading of THC-MNPs in the starch based nanoparticles was found to be high.

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

    Science.gov (United States)

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

    2013-09-11

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

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

    International Nuclear Information System (INIS)

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

  7. Hollow superparamagnetic PLGA/Fe 3O 4 composite microspheres for lysozyme adsorption

    Science.gov (United States)

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-01

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe3O4 composite microspheres composed of an inner cavity, PLGA inner shell and Fe3O4 outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe3O4 nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 ?m showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g-1) and high efficiency in lysozyme adsorption.

  8. Hollow superparamagnetic PLGA/Fe3O4 composite microspheres for lysozyme adsorption.

    Science.gov (United States)

    Yang, Qi; Wu, Yao; Lan, Fang; Ma, Shaohua; Xie, Liqin; He, Bin; Gu, Zhongwei

    2014-02-28

    Uniform hollow superparamagnetic poly(lactic-co-glycolic acid) (PLGA)/Fe(3)O(4) composite microspheres composed of an inner cavity, PLGA inner shell and Fe(3)O(4) outer shell have been synthesized by a modified oil-in-water (O/W) emulsion-solvent evaporation method using Fe(3)O(4) nanoparticles as a particulate emulsifier. The obtained composite microspheres with an average diameter of 2.5 ?m showed excellent monodispersity and stability in aqueous medium, strong magnetic responsiveness, high magnetite content (>68%), high saturation magnetization (58 emu g(-1)) and high efficiency in lysozyme adsorption. PMID:24492410

  9. Surface modification of Fe3O4@SiO2 microsphere by silane coupling agent

    Science.gov (United States)

    Ahangaran, Fatemeh; Hassanzadeh, Ali; Nouri, Sirous

    2013-04-01

    In the present study, Fe3O4@SiO2 core-shell microspheres were prepared via two steps. First, Fe3O4 nanoparticles were synthesized by co-precipitation of Fe+3 and Fe+2 as reaction substrates and NaOH as precipitant. Second, the surface of Fe3O4 was coated with silica by hydrolysis of tetraethylorthosilicate as the silica source. Subsequently, in order to reduce the amount of interaction and the agglomeration of Fe3O4@SiO2 microspheres, the silica shell of these particles was modified by vinyltriethoxysilane as the silane coupling agent. The structural properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy analyses. The results indicated that the average sizes of Fe3O4 and Fe3O4@SiO2 particles were about 50 and 500 nm, respectively. Also, the surface characterization of Fe3O4@SiO2 microspheres showed that the silane coupling agent was covalently coupled with the silica surface.

  10. Magnetically labeled cells with surface-modified fe3 o4 spherical and rod-shaped magnetic nanoparticles for tissue engineering applications.

    Science.gov (United States)

    Gil, Sara; Correia, Clara R; Mano, João F

    2015-04-01

    Magnetically targeted cells with internalized magnetic nanoparticles (MNPs) could allow the success of cell transplantation and cell-based therapies, overcoming low cell retention that occurs when delivering cells by intravenous or local injection. Upon magnetization, these cells could then accumulate and stimulate the regeneration of the tissue in situ. Magnetic targeting of cells requires a detailed knowledge between interactions of engineered nanomaterials and cells, in particular the influence of shape and surface functionalization of MNPs. For the first time, cellular internalization of amino surface-modified iron oxide nanoparticles of two different shapes (nanospheres or nanorods) is studied. MNPs show high cellular uptake and labeled cells could exhibit a strong reaction with external magnetic fields. Compared to nanorods, nanospheres show better internalization efficiency, and labeled cells exhibit strong transportation reaction with external magnetic fields. Contiguous viable cell-sheets are developed by magnetic-force-based tissue engineering. The results confirm that the developed magnetic-responsive nano-biomaterials have potential applicability in tissue engineering or cellular therapies. PMID:25641785

  11. Core-shell superparamagnetic Fe3O4@?-CD composites for host-guest adsorption of polychlorinated biphenyls (PCBs).

    Science.gov (United States)

    Wang, Manlin; Liu, Peng; Wang, Yu; Zhou, Dongmei; Ma, Chen; Zhang, Dongju; Zhan, Jinhua

    2015-06-01

    The effective recognition and enrichment of trace polychlorinated biphenyls (PCBs) in the environment are currently challenging issues due to human health concerns. In this paper, a surface absorptive layer coating superparamagnetic Fe3O4 nanoparticles for PCBs enrichment were prepared. This protocol involved the synthesis of Fe3O4 particles through a solvothermal reaction and the covering of a silica layer bonded ?-cyclodextrin (?-CD) over Fe3O4 via a sol-gel process to construct core-shell Fe3O4@?-CD composites. ?-CD was linked covalently to Fe3O4 nanoparticles to generate the binding sites, enhancing the stability of Fe3O4 nanoparticles in water. Meanwhile, superparamagnetic Fe3O4 core could be rapidly separated from matrix to simplify time-consuming washing extraction. The adsorption capacity of Fe3O4@?-CD composites to PCB28 and PCB52 in aqueous solutions was investigated. To estimate the theoretical binding site number of Fe3O4@?-CD, the obtained binding data were replotted according to Scatchard equation. The host-guest interaction between ?-CD and PCBs were further examined with density functional theory (DFT) calculations. It provides theoretical evidence of ?-CD as host molecule has a higher binding amount towards PCB-28 than PCB-52 on the basis of their optimized geometries and calculated complexation energies. The nanomaterial reported herein is an ideal candidate for various applications, including the recognition and removal of environmentally deleterious substances. PMID:25687400

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

    International Nuclear Information System (INIS)

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

  13. Fe3O4NPs mediated nonenzymatic electrochemical immunosensor for the total protein of Nosema bombycis detection without addition of substrate.

    Science.gov (United States)

    Xie, Hua; Zhang, Qiqi; Wang, Qin; Chai, Yaqin; Yuan, Yali; Yuan, Ruo

    2015-04-01

    In this work, we proposed a novel electrochemical immunosensor for sensitive detection of the total protein of Nosema bombycis based on Fe3O4 nanoparticles (Fe3O4NPs) as catalyst to electrocatalyze the reduction of methylene blue (MB) with the aid of Fe3O4NPs-DNA dendrimers for the signal amplification. PMID:25806964

  14. Fast identification of lipase inhibitors in oolong tea by using lipase functionalised Fe3O4 magnetic nanoparticles coupled with UPLC-MS/MS.

    Science.gov (United States)

    Zhu, Yuan-Ting; Ren, Xiao-Yun; Yuan, Li; Liu, Yi-Ming; Liang, Jian; Liao, Xun

    2015-04-15

    Oolong tea is an important member in tea family, which claims for various health benefits such as preventing obesity and improving lipid metabolism. In this work, using pancreatic lipase (PL) functionalised magnetic nanoparticles (PL-MNPs) as solid phase extraction absorbent in combination with ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), we developed a method for rapid screening and identification of lipase inhibitors from oolong tea. Three PL ligands were selectively extracted and identified as (-)-epigallocatechin-3-O-gallate (EGCG), (-)-gallocatechin-3-O-gallate (GCG) and (-)-epicatechin-3-O-gallate (ECG). Their lipase inhibitory activities were significantly higher than those non-ligands. Structure-activity analysis revealed that the presence of a galloyl moiety in the structure was required for binding to PL-MNPs, and therefore, exhibiting a strong inhibition on the enzyme. Taking advantages of the specificity in enzyme binding and the convenience of magnetic separation, this method has great potential for fast screening of lipase inhibitors from natural resources. PMID:25466054

  15. Catalysis of Rice Straw Hydrolysis by the Combination of Immobilized Cellulase from Aspergillus niger on ?-Cyclodextrin-Fe3O4 Nanoparticles and Ionic Liquid

    Science.gov (United States)

    Huang, Po-Jung; Chang, Ken-Lin; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto ?-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11?U?g immobilized cellulase?1 at an ionic liquid concentration of 200?mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739?g?h?1?L?1. One of the advantages of immobilized cellulase is high reusability—it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15?g?L?1). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  16. Magnetic Fe3O4-Au core-shell nanostructures for surface enhanced Raman scattering

    International Nuclear Information System (INIS)

    The synthesis, structural and optical characterization, and application of superparamagnetic and water-dispersed Fe3O4-Au core-shell nanoparticles for surface enhanced Raman scattering (SERS) is reported. The structure of the nanoparticles was determined by scanning transmission electron microscopy (STEM) and high-resolution transmission electron microscopy (HRTEM). STEM images of the Fe3O4-Au core-shell nanoparticles reveal an average diameter of 120 nm and a high degree of surface roughness. The nanoparticles, which display superparamagnetic properties due to the core Fe3O4 material, exhibit a visible surface plasmon resonance (SPR) peaked at 580 nm due to the outer gold shell. The nanoparticles are used as a substrate for surface enhanced Raman scattering (SERS) with rhodamine 6G (R6G) as a Raman reporter molecule. The SERS enhancement factor is estimated to be on the order of 106, which is ? 2 times larger than that of conventional gold nanoparticles (AuNPs) under similar conditions. Significantly, magnetically-induced aggregation of the Fe3O4-Au core-shell nanoparticles substantially enhanced SERS activity compared to non-magnetically-aggregated Fe3O4-Au nanoparticles. This is attributed to both increased scattering from the aggregates as well as ''hot spots'' due to more junction sites in the magnetically-induced aggregates. The magnetic prolly-induced aggregates. The magnetic properties of the Fe3O4 core, coupled with the optical properties of the Au shell, make the Fe3O4-Au nanoparticles unique for various potential applications including biological sensing and therapy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    International Nuclear Information System (INIS)

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

  18. Supercritical fluid mediated synthesis of poly(2-hydroxyethyl methacrylate)/Fe3O4 hybrid nanocomposite

    International Nuclear Information System (INIS)

    Graphical abstract: We successfully developed an easier and more effective method to prepare a magnetic polymer nanocomposite by in situ radical polymerization of 2-hydroxyethyl methacrylate in the presence of the surface-modified Fe3O4 nanoparticles with a coupling agent in supercritical CO2. FE-TEM pictures showed that the nanoparticles were well dispersed in the polymer matrix. The incorporation of Fe3O4 in the nanocomposite was confirmed by FT-IR, XRD and XPS. Thermal stability and magnetic property increase with the increasing amount of Fe3O4 nanoparticles in the composite. This new environmentally benign green synthetic route may offer advantages of easy separation and solvent removal. Highlights: ? A magnetic polymer nanocomposite (Fe3O4-g-PHEMA) was successfully synthesized via in-situ dispersion polymerization in supercritical carbon dioxide. ? The Fe3O4 nanoparticles were well dispersed in the polymer matrix. ? The resulting nanocomposites have an excellent superparamagnetic property, which is favorable for their bio-applications. ? This new environmentally benign green synthetic route offers advantages of avoiding the use of organic solvents as well as easy separation of solvent. - Abstract: Poly(2-hydroxyethyl methacrylate) (PHEMA) and magnetic nanoparticle (Fe3O4) hybrid nanocomposite was synthesized by disnocomposite was synthesized by dispersion polymerization in supercritical carbon dioxide (scCO2) using a copolymeric stabilizer, poly[(2-dimethylamino)ethyl methacrylate-co-1H,1H-perfluorooctyl methacrylate] (PDMAEMA-co-PFOMA). Fe3O4 nanoparticles were first surface-modified with a silane coupling agent methacryloxypropyltrimethoxysilane (MPTMS), which provides a reactive C=C bond and can copolymerize with 2-hydroxyethyl methacrylate (HEMA). After immobilization of the silane coupling agent, polymer chains were successfully grafted onto the surface of Fe3O4, resulting in the formation of core-shell nanostructure. FE-TEM pictures showed that the nanoparticles were well dispersed in the polymer matrix. The incorporation of Fe3O4 in the nanocomposite was confirmed by FT-IR, XRD and XPS. Thermal stability and magnetic property increase with the increasing amount of Fe3O4 nanoparticles in the composite. This new environmentally benign green synthetic route may offer advantages of easy separation and solvent removal.

  19. Fe3O4/PPy composite nanospheres as anode for lithium-ion batteries with superior cycling performance

    International Nuclear Information System (INIS)

    Uniform Fe3O4/PPy composite nanospheres (FPCNs) with Fe3O4 nanoparticles embedded in PPy nanospheres (?200 nm) were prepared by a hydrothermal process followed by an ultrasonication assisted polymerization. For the first time, FPCNs were used as anode for lithium ion batteries, demonstrating enhanced electrochemical performance with high reversible capacity (544 mA h g?1 after 300 cycles), remarkable capacity retention (98% of the initial capacity after 300 cycles), as well as good rate capability (332 mAh g?1 at 2000 mA g?1). The spherical PPy matrix in FPCNs possesses three functions: 1) buffering the structural variation of Fe3O4 nanoparticles during charging/discharging process; 2) preventing the aggregation of Fe3O4 nanoparticles; 3) avoiding the direct contact between Fe3O4 nanoparticles and the electrolyte. The results observed in this study may shed some light on the investigation of MOx/polymer composite electrode materials

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

    International Nuclear Information System (INIS)

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

  1. Facile synthesis of new nano sorbent for magnetic solid-phase extraction by self assembling of bis-(2,4,4-trimethyl pentyl)-dithiophosphinic acid on Fe3O4@Ag core@shell nanoparticles: characterization and application.

    Science.gov (United States)

    Tahmasebi, Elham; Yamini, Yadollah

    2012-12-01

    A novel sorbent for magnetic solid-phase extraction by self-assembling of organosulfur compound, (bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid), onto the silver-coated Fe(3)O(4) nanoparticles was introduced. Due to the formation of covalent bond of S-Ag, the new coating on the silver surface was very stable and showed high thermal stability (up to 320°C). The size, morphology, composition, and properties of the prepared nanoparticles have also been characterized and determined using scanning electron microscopy (SEM), energy-dispersive X-ray analyzer (EDX), dynamic light scattering (DLS), Fourier transform-infrared (FT-IR) spectroscopy, and thermal gravimetric analysis (TGA). Extraction efficiency of the new sorbent was investigated by extraction of five polycyclic aromatic hydrocarbons (PAHs) as model compounds. The optimum extraction conditions for PAHs were obtained as of extraction time, 20 min; 50 mg sorbent from 100 mL of the sample solution, and elution with 100 ?L of 1-propanol under fierce vortex for 2 min. Under the optimal conditions, the calibration curves were obtained in the range of 0.05-100 ?g L(-1) (R(2)>0.9980) and the LODs (S/N=3) were obtained in the range of 0.02-0.10 ?g L(-1). Relative standard deviations (RSDs) for intra- and inter-day precision were 2.6-4.2% and 3.6-8.3%, respectively. In addition, feasibility of the method was demonstrated with extraction and determination of PAHs from some real samples containing tap water, hookah water as well as soil samples with relative recovery of 82.4-109.0% and RSDs of 3.5-11.6%. PMID:23176735

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

    International Nuclear Information System (INIS)

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

  3. Synthesis and characterization of Fe3O4 magnetic nanofluid

    Scientific Electronic Library Online (English)

    Javier A, Lopez; Ferney, González; Flavio A, Bonilla; Gustavo, Zambrano; Maria E, Gómez.

    2010-06-01

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

  4. Core-Shell Nano structure of a-Fe2O3/Fe3O4: Synthesis and Photo catalysis for Methyl Orange

    International Nuclear Information System (INIS)

    Fe3O4 nanoparticle was synthesized in the solution involving water and ethanol. Then, a-Fe2O3 shell was produced in situ on the surface of the Fe3O4 nanoparticle by surface oxidation in molten salts, forming ?-Fe2O3/Fe3O4 core-shell nano structure. It was showed that the magnetic properties transformed from ferromagnetism to superparamagnetism after the primary Fe3O4 nanoparticles were oxidized. Furthermore, the obtained a-Fe2O3/Fe3O4 core-shell nanoparticles were used to photo catalyse solution of methyl orange, and the results revealed that a-Fe2O3/Fe3O4 nanoparticles were more efficient than the self-prepared ?-Fe2O3 nanoparticles. At the same time, the photo catalyzer was recyclable by applying an appropriate magnetic field.

  5. A simple way to prepare Pd/Fe3O4/polypyrrole hollow capsules and their applications in catalysis.

    Science.gov (United States)

    Yao, Tongjie; Zuo, Quan; Wang, Hao; Wu, Jie; Xin, Baifu; Cui, Fang; Cui, Tieyu

    2015-07-15

    Preparation of catalysts with good catalytic activity and high stability, together with magnetic separation property, in a simple way is highly desirable. In this paper, we reported a novel strategy to construct magnetic recyclable hollow capsules with Pd and Fe3O4 nanoparticles embedded in polypyrrole (PPy) shell via only two steps: first, synthesization of Pd nanoparticles, preparation of Fe3O4 nanoparticles, and formation of PPy shell were finished in one-step on the surface of polystyrene (PS) nanospheres; then, the PS core was selectively removed by tetrahydrofuran. The Pd/Fe3O4/PPy hollow capsules exhibited good catalytic property in reduction of 4-nitrophenol with NaBH4 as reducing agent, and the reaction rate constants were calculated through pseudo-first-order reaction equation. Due to incorporation of Fe3O4 nanoparticles, the catalysts could be quickly separated from the reaction solution by magnet and reused without obvious catalytic loss. Besides catalytic property and reusability, their stability was also examined by HNO3 etching experiment. Compared with bare Pd and Fe3O4 nanoparticles, the stability of both Pd and Fe3O4 nanoparticles in hollow capsules was largely improved owing to the protection of PPy shell. The good catalytic performance, ease of separation, high stability and especially a simple preparation procedure, made Pd/Fe3O4/PPy hollow capsules highly promising candidates for diverse applications. PMID:25845884

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

    Directory of Open Access Journals (Sweden)

    Qing Chang

    2014-09-01

    Full Text Available 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 crosslinking agent. Immobilization conditions were optimized to obtain the highest relative activity of the immobilized enzyme. It was found the durability of the immobilized enzyme to heating and pH variation were improved in comparison with free HRP. The apparent Michaelis constants of the immobilized HRP and free HRP with substrate were compared, showing that the enzyme activity of the immobilized HRP was close to that of free HRP. The HRP immobilized particles, as an enzyme catalyst, were used to activate H2O2 for degrading 2,4-dichlorophenol. The rapid degradation of 2,4-dichlorophenol indicated that the immobilized enzyme has potential applications for removing organic pollutants.

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

    Science.gov (United States)

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

    2013-03-01

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

  8. Incorporation of Fe3O4/CNTs nanocomposite in an epoxy coating for corrosion protection of carbon steel

    Science.gov (United States)

    Pham, Gia Vu; Truc Trinh, Anh; To, Thi Xuan Hang; Duong Nguyen, Thuy; Trang Nguyen, Thu; Hoan Nguyen, Xuan

    2014-09-01

    In this study Fe3O4/CNTs composite with magnetic property was prepared by attaching magnetic nanoparticles (Fe3O4) to carbon nanotubes (CNTs) by hydrothermal method. The obtained Fe3O4/CNTs composite was characterized by Fourier transform infrared (FTIR) spectroscopy, powder x-ray diffraction and transmission electron microscopy. The Fe3O4/CNTs composite was then incorporated into an epoxy coating at concentration of 3 wt%. Corrosion protection of epoxy coating containing Fe3O4/CNTs composite was evaluated by electrochemical impedance spectroscopy and adhesion measurement. The impedance measurements show that Fe3O4/CNTs composite enhanced the corrosion protection of epoxy coating. The corrosion resistance of the carbon steel coated by epoxy coating containing Fe3O4/CNTs composite was significantly higher than that of carbon steel coated by clear epoxy coating and epoxy coating containing CNTs. FE-SEM photographs of fracture surface of coatings showed good dispersion of Fe3O4/CNTs composite in the epoxy matrix.

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

    Directory of Open Access Journals (Sweden)

    Xiao Qi

    2009-01-01

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

  10. Polymide/Fe3O4-carbonized Membranes for Gas Separation

    Directory of Open Access Journals (Sweden)

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

    2010-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Kalantari K

    2013-05-01

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

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

    International Nuclear Information System (INIS)

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

  13. Solvothermal in situ synthesis of Fe3O4-multi-walled carbon nanotubes with enhanced heterogeneous Fenton-like activity

    International Nuclear Information System (INIS)

    Graphical abstract: After purification, the multi-wall carbon nanotubes (MWCNTs) act as seeds for Fe3O4 nanoparticles heterogeneous nucleation. The Fe3O4 nanoparticles with diameter range of 4.2–10.0 nm synthesized in situ on the MWCNTs under solvothermal condition. The formed nano Fe3O4-MWCNTs decolorized the Acid Orange II effectively via Fenton-like reaction. Highlights: ? The amount of water tunes size and size distribution of the Fe3O4 nanoparticles (FNs). ? FNs are homogeneously coated on the multi-walled carbon nanotubes (MWCNTs). ? FNs have diameters in the range of 4.2–10.0 nm, average grain size of 7.4 nm. ? Fe3O4-MWCNTs are used as a Fenton-like catalyst to decompose Acid Orange II. ? Fe3O4-MWCNTs displayed a higher activity than nanometer-size Fe3O4. -- Abstract: Fe3O4-multi-walled carbon nanotubes (Fe3O4-MWCNTs) hybrid materials were synthesized by a solvothermal process using acid treated MWCNTs and iron acetylacetonate in a mixed solution of ethylene glycol and ultrapure water. The materials were characterized using X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and vibrating sample magnetometry. The results showed that a small amount of water in the synthesis system played a role in controlling crystal phase formation, size of Fe3O4, and the homogeneous distribution of the Fe3O4 nanoparticles deposited on the MWCNTs. The Fe3O4 nanoparticles had diameters in the range of 4.2–10.0 nm. They displayed good superparamagnetism at room temperature and their magnetization was influenced by the reaction conditions. They were used as a Fenton-like catalyst to decompose Acid Orange II and displayed a higher activity than nanometer-size Fe3O4.

  14. Bifunctional Fe3O4@Gd2O3:Eu3+nanocomposites obtained by the homogeneous precipitation method

    International Nuclear Information System (INIS)

    Graphical abstract: The TEM images reveal clearly the core–shell structures because of the obvious difference in contrast between the central part and the fringe, which indicates the Gd2O3:Eu3+ layer had successfully deposited on the magnetite Fe3O4 cores. And Fe3O4@Gd2O3:Eu3+ nanoparticles keep the spherical morphology, non-aggregation and rough surface. The images reveal that the average diameters of the Fe3O4 and Fe3O4@Gd2O3:Eu3+ nanoparticles are ?200 nm and ?250 nm, respectively. The thickness of Gd2O3:Eu3+ layer is ?25 nm. Highlights: ? Fe3O4@Gd2O3:Eu3+ nanocomposites were synthesized by homogeneous precipitation method. ? Formation of core–shell nanostructure revealed by transmission electron microscopy. ? Fe3O4@Gd2O3:Eu3+ nanocomposites showed magnetic behavior and fluorescence properties. ? Possible applications including bioseparation, drug delivery system, bio-labels, etc. - Abstract: An easy homogeneous precipitation method was developed for the synthesis of bifunctional magnetic-fluorescent nanocomposites with Fe3O4 nanoparticles as the core and europium-doped gadolinium oxide (Gd2O3:Eu3+) as the shell. The nanocomposites showed both strong magnetic behavior and unique Eu-related fluorescence properties with a high emission intensity, which may lead to development of nanocomposites with great potential for applications in drug targeting, biosensors, and diagnostic analysis

  15. Differential Scanning Calorimetry Investigations on Polyvinylidene Fluoride - Fe3O4 Nanocomposites

    Science.gov (United States)

    Salinas, Samantha; Jones, Robert; Chipara, Dorina M.; Chipara, Mircea

    2015-03-01

    Nanocomposites of polyvinylidene fluoride (PVDF)-magnetite (Fe3O4) with various weight fractions of nanofiller (0%, 0.2 %, 0.6 %, 1.2%, 2.4 %, 5.8 %, 12 %, 23 %, and 30 %) have been obtained via melt mixing by loading PVDF with Fe3O4 particles (average size 75 nm from Nanostructured & Amorphous Materials, Inc). Thermal stability of PVDF-Fe3O4 has been investigated by TGA in nitrogen. The increase of the thermal stability of PVDF due to the loading with Fe3O4 was quantified by the shift of the temperature at which the (mass) degradation rate is maximum as a function of Fe3O4 content. The effect of the nanofiller on the crystallization of PVDF was investigated by isothermal DSC (TA Instruments, Q500). Non isothermal DSC tests, (at various heating rates ranging from 1 to 25 °C/min) have been used to locate the glass, crystallization, and melting temperatures. The dependence of the glass, crystallization, and melting temperatures on the concentration of nanoparticles is reported and analyzed in detail. The data are critically analyzed within the classical Avrami theory.

  16. Synergies of the crystallinity and conductive agents on the electrochemical properties of the hollow Fe3O4 spheres

    International Nuclear Information System (INIS)

    Highlights: ? Hollow Fe3O4 spheres with different diameters were obtained from solvothermal route. ? Hollow Fe3O4 spheres have excellent electrochemical performance as an anode material. ? The crystallinity and conductive agents have synergies on the discharge capacity. - Abstract: Monodispersed hollow Fe3O4 spheres with different diameters and shell thickness were synthesized by a simple solvothermal process and were investigated as anode materials for lithium ion batteries (LIBs). The shell of the hollow spheres exhibited porous structure composed of aggregated Fe3O4 nanoparticles. The composition and morphology of the obtained samples were characterized by X-ray powder diffraction (XRD), Raman spectra, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A novel formation mechanism was proposed based on the results of time-dependent reactions. The electrochemical tests of the hollow Fe3O4 spheres were performed to determine the reversible capacity, rate and cycling performance as anode materials for LIBs. The Fe3O4 obtained from the reaction at 200 °C for 48 h exhibited the best specific capacity and capacity retention and superior rate performance compared to other Fe3O4 spheres, which is ascribed to their reasonable particle size, high crystallinity and hollow spherical structurenity and hollow spherical structures. Different conductive additive were used to investigate the electrochemical performance of Fe3O4 hollow spheres. The binary conductive additives containing acetylene black (AB) and carbon nanobutes (CNTs) improved the electrochemical performance of the Fe3O4 hollow spheres obviously. The results reveal that there is a synergistic effect of the particle size, crystallinity and conductive agents on the electrochemical properties of the hollow Fe3O4 spheres.

  17. Water Gas Shift Chemistry at the Fe3O4 (001) Surface

    International Nuclear Information System (INIS)

    Full text: Magnetite (Fe3O4) is an important material in heterogeneous catalysis, both as an active surface and as a support for metal nanoparticles. The water gas shift reaction, in which CO is oxidized to CO2 and H2O is reduced to H2, is performed over an iron-oxide catalyst. Fe3O4 has been identified as the active phase, but important details such as the active intermediates and the reaction pathway are not clear. Using a combination of high pressure XPS and STM, we study the reaction of H2O and CO on the Fe3O4(001) surface and observe formation of formate and methoxy species. (author)

  18. Enhanced interfacial polarization relaxation effect on microwave absorption properties of submicron-sized hollow Fe3O4 hemispheres

    International Nuclear Information System (INIS)

    Bowl-like Fe3O4 hemispheres with a hollow structure have been synthesized with an average outer diameter of 250 nm and a shell thickness of 80 nm using tiny ?25 nm Fe3O4 nanoparticles. The complex permittivity, complex permeability and reflection loss of the samples in weight percentages of 60% of the hollow Fe3O4 hemispheres were studied by using an Agilent E5071 C vector network analyzer in the frequency range of 2–18 GHz. Results show that as-prepared samples exhibit improved microwave absorbing properties compared with our previously reported ball-like Fe3O4 microspheres and Fe3O4 hemispheres/r-GO composites. Two Cole–Cole semicircles reveal that there are dual dielectric relaxation losses: one is interfacial polarization relaxation, the other is dipolar relaxation. X-ray photoelectron and Fourier transform infrared spectra of the products calcinated at different temperatures reveal the enhanced interfacial polarization relaxation effect due to the higher concentration of Fe2+ ions in the surface layer and increased interfaces among the Fe3O4 nanoparticles that form the submicron-sized hollow Fe3O4 hemispheres. In addition, the fitted results of complex permeability demonstrate that the magnetic loss is mainly caused by the Kittel natural resonance. (paper)

  19. Fabrication of shape controlled Fe3O4 nanostructure

    International Nuclear Information System (INIS)

    Shape-controlled Fe3O4 nanostructure has been successfully prepared using polyethylene glycol as template in a water system at room temperature. Different morphologies of Fe3O4 nanostructures, including spherical, cubic, rod-like, and dendritic nanostructure, were obtained by carefully controlling the concentration of the Fe3+, Fe2+, and the molecular weight of the polyethylene glycol. Transmission Electron Microscope images, X-ray powder diffraction patterns and magnetic properties were used to characterize the final product. This easy procedure for Fe3O4 nanostructure fabrication offers the possibility of a generalized approach to the production of single and complex nanocrystalline oxide with tunable morphology.

  20. Magnetically separable Cu2O/chitosan-Fe3O4 nanocomposites: Preparation, characterization and visible-light photocatalytic performance

    Science.gov (United States)

    Cao, Chunhua; Xiao, Ling; Chen, Chunhua; Cao, Qihua

    2015-04-01

    A novel magnetically-separable visible-light-induced photocatalyst, Cu2O/chitosan-Fe3O4 nanocomposite (Cu2O/CS-Fe3O4 NC), was prepared via a facile one-step precipitation-reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu2O/CS-Fe3O4 NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV-vis/DRS. The photocatalytic activity of Cu2O/CS-Fe3O4 NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu2O/CS-Fe3O4 NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu2O was wrapped in chitosan matrix embedded with Fe3O4 nanoparticles. The tight combination of magnetic Fe3O4 and semiconductor Cu2O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu2O/CS-Fe3O4 NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B were still above 87% after five reaction cycles, indicating that Cu2O/CS-Fe3O4 NCs had excellent reusability and stability.

  1. High rate capability and long cycle stability Fe3O4–graphene nanocomposite as anode material for lithium ion batteries

    International Nuclear Information System (INIS)

    Highlights: ? Fabrication of graphene and Fe3O4 nanocomposite for lithium ion batteries anode. ? In situ synthesis method leads to small particle size. ? Small particle size results in fine and strong interfacial interaction. ? The nanocomposite shows high rate capability and super long cycling stability. - Abstract: We developed one-spot in situ synthesis method to form nanocomposite of reduced graphene oxide (RGO) sheets with Fe3O4 nanoparticles for lithium ion battery applications. A transmission electron microscopy image has shown that the as-formed Fe3O4 nanoparticles are about 10 nm in average size, and uniformly anchor on RGO sheets as spacers to keep the neighboring sheets separated. The Fe3O4–RGO nanocomposite exhibits improved rate capability of 436 mA h g?1 at 2400 mA g?1. It delivers a high capacity of 1188 mA h g?1 at 100 mA g?1 after 1000 cycles of charge and discharge at various rates from 100 to 6000 mA g?1, indicating outstanding cycle stability. The improved electrochemical performance can be attributed to the important interfacial interaction between small-sized Fe3O4 nanoparticles and ultrathin RGO nanosheets, and suggests that Fe3O4–RGO nanocomposite with superior performance will be a promising anode material for lithium ion batteries.ion batteries.

  2. Synthesis of silica-coated Au with Ag, Co, Cu, and Ir bimetalic radioisotope nanoparticle radiotracers

    International Nuclear Information System (INIS)

    Silica-coated Au with Ag, Co, Cu, and Ir bimetallic radioisotope nanoparticles were synthesized by neutron irradiation, after coating SiO2 onto the bimetallic particles by the sol-gel Stober process. Bimetallic nanoparticles were synthesized by irradiating aqueous bimetallic ions at room temperature. Their shell and core diameters were recorded by TEM to be 100 - 112 nm and 20 - 50 nm, respectively. The bimetallic radioisotope nanoparticles' gamma spectra showed that they each contained two gamma-emitting nuclides. The nanoparticles could be used as radiotracers in petrochemical and refinery processes that involve temperatures that would decompose conventional organic radioactive labels.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

    CERN Document Server

    Dash, Monika

    2013-01-01

    Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

  7. Functionalized silica coated magnetic nanoparticles with biological species for magnetic separation

    OpenAIRE

    Yu, Ch; Tam, Ky; Lo, Cch; Tsang, Sc

    2007-01-01

    Magnetic nanoparticle captured in a thin functional coating as magnetic separable nano-vehicle for carrying chemical species is a hot and challenging area. Here, we report a synthesis of silica encapsulated magnetic nanosize particles (4-11 nm) as a magnetic separable carrier based on a simple microemulsion technique. The silica coating surface is shown to isolate and protect the magnetic core from reactive environment where a range of conditions for magnetic separation can be made possible. ...

  8. Chemically synthesized Au–Fe3O4 nanostructures with controlled optical and magnetic properties

    Science.gov (United States)

    Velasco, Victor; Muñoz, Laura; Mazarío, Eva; Menéndez, Nieves; Herrasti, Pilar; Hernando, Antonio; Crespo, Patricia

    2015-01-01

    Au–Fe3O4 dumbbell-like, flower-like and core-shell nanostructures with different sizes ranging between 4–15?nm have been synthesized via the thermal decomposition of iron pentacarbonyl and reduction of gold salts. By means of the variation of the precursors’ molar ratio, the injection temperature and the reaction time, the optical and magnetic properties have been tailored. A strong dependence on the dielectric function of the present Fe3O4 nanoparticles (NPs) was detected. The gold characteristic plasmon peak shifts from 525?nm (pure gold NPs) to close to 600?nm showing an electron damping in the Au NPs surrounded by Fe3O4. These NPs are ferromagnetic at low temperature, exhibiting a coercive field ranging between 85–500?Oe, whereas they behave as a superparamagnetic system above the blocking temperature, which is found to be between 18–110?K. A high magnetic anisotropy is generated in the interface of Au–Fe3O4 NPs.

  9. A novel technique to extract Bi from mechanochemically prepared Bi-Fe3O4 nanocomposite

    International Nuclear Information System (INIS)

    The solid-state reduction of Bi2O3 to bismuth (Bi) nanoparticles by high-energy ball milling of raw materials (Bi2O3 and Fe) in air and argon atmospheres has been described. XRD results show that in addition to bismuth, a second phase of nanocrystalline magnetite is also formed. This is due to the formation of Fe2O3 and the subsequent change to Fe3O4 in the course of ball milling. Mean particle sizes of the obtained Bi and Fe3O4 particles were 22 and 18 nm, respectively, using Scherrer's formula. A saturation magnetization of 80 emu/g is achieved for magnetic phase (Fe3O4). As both Bi and magnetite were nanosized particles, it was not possible to separate these two phases by the magnetic separation technique. A novel technique based on different thermal expansions of the Bi and Fe3O4 was then used to extract metallic Bi from the as-milled powders

  10. Tribological Properties of Graphene-based Fe3O4 Nanocomposite Materials

    Directory of Open Access Journals (Sweden)

    QIAO Yu-Lin, ZHAO Hai-Chao, ZANG Yan, ZHANG Qing

    2015-01-01

    Full Text Available Graphene-based Fe3O4 nanocomposite materials were prepared by the melthod of Liquid-phase Ultrasonic Exfoliation. Morphologies of nanocomposite materials were characterized by means of SEM and TEM. Its tribological properties as a pure water additive were investigated using multi-functional reciprocating friction and wear tester. The lubrication mechanism was discussed based on results of analyses of SEM, XPS. The results showed that the Fe3O4 nanoparticles with size of 20­90 nm were densely and randomly deposited on interlamination and surface of graphene sheets. The nanocomposite materials as a pure water additive displayed good friction-reducing and antiwear performance. Compared with pure water, the graphene-based Fe3O4 nanocomposite could reduce the friction coefficient of 26.7% and the wear mass of 35.4% under condition of 10 N of load and 0.01wt% of concentration. The prosperity was attributed to the effect of adsorption membrane and boundary lubrication film containing graphene and Fe3O4 which inhibited oxidation of Fe and reduced wear on the frictional surface.

  11. Nanoarchitectured Fe3O4 array electrode and its excellent lithium storage performance

    International Nuclear Information System (INIS)

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

  12. MAPLE Fabricated Fe3O4@Cinnamomum verum Antimicrobial Surfaces for Improved Gastrostomy Tubes

    OpenAIRE

    Alina Georgiana Anghel; Alexandru Mihai Grumezescu; Mariana Chirea; Valentina Grumezescu; Gabriel Socol; Florin Iordache; Alexandra Elena Oprea; Ion Anghel; Alina Maria Holban

    2014-01-01

    Cinnamomum verum-functionalized Fe3O4 nanoparticles of 9.4 nm in size were laser transferred by matrix assisted pulsed laser evaporation (MAPLE) technique onto gastrostomy tubes (G-tubes) for antibacterial activity evaluation toward Gram positive and Gram negative microbial colonization. X-ray diffraction analysis of the nanoparticle powder showed a polycrystalline magnetite structure, whereas infrared mapping confirmed the integrity of C. verum (CV) functional groups after the laser transfer...

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

    International Nuclear Information System (INIS)

    Highlights: ? Nano-Fe3O4 was coated onto polystyrene (PS) beads to obtain PS-Fe3O4 for arsenate removal from water. ? PS-Fe3O4 exhibited higher capacity and faster kinetics for arsenate adsorption than Fe3O4. ? PS-Fe3O4 can be effectively separated from water under a low magnetic field (3O4 can be employed for multiple uses after regeneration with alkaline solution. - Abstract: Fe3O4 is a promising material for arsenic sequestration due to its specific affinity toward arsenic and feasible magnetic separation. How to further increase its adsorption capacity while maintain its low-field separation is an interesting but challenging task. In this study nano-Fe3O4 was successfully coated onto the outer surface of polystyrene (PS) beads of 350–400 nm in diameter by the hetero-coacervation method, and the resulting composite PS-Fe3O4 was characterized using transmission electron microscope (TEM), X-ray powder diffraction (XRD), and electrophoresis measurement (EM). Its adsorption toward arsenate was investigated as a function of solution pH, arsenic concentration, contact time, and coexisting anions. The maximum adsorption capacity of PS-Fe3O4 was 139.3 mg/g Fe3O4, 77.7% greater than that of bulky Fe33O4. More attractively, it can be readily separated from water under a low magnetic field (3O4 can be effectively regenerated by NaOH solution, and the regenerated composite beads could be employed for repeated use without significant capacity loss, indicating that nano-Fe3O4 was steadily coated onto the surface of PS beads. Generally, PS beads could be employed as a promising host to fabricate efficient composites originated from Fe3O4 or other nanoparticles for environmental remediation.

  14. Fabrication, characterization and measurement of thermal conductivity of Fe3O4 nanofluids

    International Nuclear Information System (INIS)

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

  15. Lipid peroxidation and its control in Anguilla anguilla hepatocytes under silica-coated iron oxide nanoparticles (with or without mercury) exposure.

    Science.gov (United States)

    Srikanth, Koigoora; Anjum, Naser A; Trindade, Tito; Duarte, Armando C; Pereira, Edurda; Ahmad, Iqbal

    2015-07-01

    Having multidisciplinary applications, iron oxide nanoparticles can inevitably enter aquatic system and impact inhabitants such as fish. However, the studies in this context have ignored the significance of obvious interaction of iron oxide nanoparticles with other persistent co-contaminants such as mercury (Hg) in the modulation of the toxicity and underlying mechanisms of iron oxide nanoparticles and Hg alone, and concomitant exposures. This study aimed to evaluate lipid peroxidation (LPO) and its control with glutathione (GSH) and associated enzymes (such as glutathione reductase, GR; glutathione peroxidase, GPX; glutathione sulfo-transferase, GST) in European eel (Anguilla anguilla L.) hepatocytes exposed to stressors with following schemes: (i) no silica-coated iron oxide nanoparticles functionalized with dithiocarbamate (Fe3O4@SiO2/Si DTC, hereafter called 'FeNPs'; size range 82?±?21 to 100?±?30 nm) or Hg, (ii) FeNPs (2.5 ?g L(-1)) alone, (iii) Hg (50 ?g L(-1)) alone and (iv) FeNPs + Hg concomitant condition during 0 to 72 h. The exhibition of a differential coordination between GSH regeneration (determined as GR activity) and GSH metabolism (determined as the activity of GPX and GST) was perceptible in A. anguilla hepatocytes in order to control FeNPs, Hg and FeNPs + Hg exposure condition-mediated LPO. This study revealed the significance of a fine tuning among GR, GPX and GST in keeping LPO level under control during FeNPs or Hg alone exposure, and a direct role of total GSH (TGSH) in the control of LPO level and impaired GSH metabolism under the concomitant (FeNPs + Hg) exposure. An interpretation of the fish risk to FeNPs in a multi-pollution state should equally consider the potential outcome of the interaction of FeNPs with other contaminants. PMID:25613805

  16. Synthesis and characterization of bifunctional hybrid nanocomposite LaPO4:5Eu at the rate Fe3O4

    International Nuclear Information System (INIS)

    A facile direct precipitation method was used for the synthesis of bifunctional magnetic-luminescence nanocomposite material. Fe3O4 magnetic nanoparticles were synthesized with coprecipitation method and LaPO4 by polyol route. The bifunctional hybrid nanocomposite was prepared by mounting Eu3+ doped LaPO4 nanoparticle with monoclinic system on superparamagnetic Fe3O4. The nanohybrid LaPO4:5Eu at the rate Fe3O4 was characterized by X-ray diffractometer (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), photoluminescence (PL) study and hyperthermia study using AC magnetic field induction heater. The Fe3O4 and LaPO4 nanoparticles are spherical particles with ? 10 and ? 23 nm sizes respectively. The FTIR spectra confirm the deposition of LaPO4:5Eu3+ over Fe3O4

  17. Aqueous route to facile, efficient and functional silica coating of metal nanoparticles at room temperature

    Science.gov (United States)

    Shah, Kwok Wei; Sreethawong, Thammanoon; Liu, Shu-Hua; Zhang, Shuang-Yuan; Tan, Li Sirh; Han, Ming-Yong

    2014-09-01

    Various metal (Ag, Au, and Pt)@thiol-functionalized silica (SiO2-SH) nanoparticles (NPs) are successfully prepared at room temperature by a facile, efficient, functional, universal and scalable coating process in alcohol-free aqueous solution using pre-hydrolyzed 3-(mercaptopropyl)trimethoxysilane (MPTMS). The controlled pre-hydrolysis of the silane precursor in water and the consecutive condensation processes are the key to achieve the effective and uniform silica coating on metal NPs in aqueous solution. The thickness of the silica shell is tuned by simply varying the coating time. The silica shell can act as an effective protecting layer for Ag NPs in Ag@SiO2-SH NPs under conditions for silica coating in aqueous solution; however, it leads to a directional dissolution of Ag NPs in a more strongly basic ammonia solution. The environmentally friendly silica coating process in water is also applied to prepare highly surface-enhanced Raman scattering (SERS)-active Ag@SiO2-SH NPs with different types of Raman molecules for highly sensitive SERS-based applications in various fields.Various metal (Ag, Au, and Pt)@thiol-functionalized silica (SiO2-SH) nanoparticles (NPs) are successfully prepared at room temperature by a facile, efficient, functional, universal and scalable coating process in alcohol-free aqueous solution using pre-hydrolyzed 3-(mercaptopropyl)trimethoxysilane (MPTMS). The controlled pre-hydrolysis of the silane precursor in water and the consecutive condensation processes are the key to achieve the effective and uniform silica coating on metal NPs in aqueous solution. The thickness of the silica shell is tuned by simply varying the coating time. The silica shell can act as an effective protecting layer for Ag NPs in Ag@SiO2-SH NPs under conditions for silica coating in aqueous solution; however, it leads to a directional dissolution of Ag NPs in a more strongly basic ammonia solution. The environmentally friendly silica coating process in water is also applied to prepare highly surface-enhanced Raman scattering (SERS)-active Ag@SiO2-SH NPs with different types of Raman molecules for highly sensitive SERS-based applications in various fields. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03306j

  18. Synthesis of BSA/Fe3O4 magnetic composite microspheres for adsorption of antibiotics

    International Nuclear Information System (INIS)

    BSA/Fe3O4 magnetic composite microspheres with high saturation magnetization and paramagnetic property were prepared via inverse emulsion technology at room temperature, bovine serum albumin (BSA, 60 KD), magnetic nanoparticles (Fe3O4) and glutaraldehyde as macromonomer, inorganic particles and cross-linking agent, respectively. Fourier transform infrared (FTIR), scanning electron microscope (SEM), metalloscope, and particle size analyzer were used to characterize morphology and structure of composite microspheres. Vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA) were used to test magnetic properties of the synthesized samples, adsorption capacity of microspheres was determined by ultraviolet spectrophotometer (UV). The results showed that BSA/Fe3O4 microspheres were 43 ?m with relatively narrow particle size distribution, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 11 emu/g, and high magnetic content with a value of 57.29%. The main factors influencing properties of microspheres including raw material ratio, the amount of emulsifier and cross-linking agent, agitation speed were investigated and optimized. Furthermore, these microspheres accompanying with high separable and reusable efficient may have great potential application in the field of separation, in particular, removal of antibiotics. Adsorption capacities of the microes of four different kinds of antibiotics (erythromycin, streptomycin, tetracycline and chloramphenicol) ranging from 69.35 mg/g to 147.83 mg/g were obtained, and Langmuir isotherm model coincided with equilibrium data than that of the Freundlich model. - Highlights: • BSA/Fe3O4 microspheres with high saturation magnetization were prepared. • BSA/Fe3O4 microspheres for the removal of antibiotics are proposed. • The obtained results have significant importance in environmental processes

  19. Efficient internalization of silica-coated iron oxide nanoparticles of different sizes by primary human macrophages and dendritic cells

    International Nuclear Information System (INIS)

    Engineered nanoparticles are being considered for a wide range of biomedical applications, from magnetic resonance imaging to 'smart' drug delivery systems. The development of novel nanomaterials for biomedical applications must be accompanied by careful scrutiny of their biocompatibility. In this regard, particular attention should be paid to the possible interactions between nanoparticles and cells of the immune system, our primary defense system against foreign invasion. On the other hand, labeling of immune cells serves as an ideal tool for visualization, diagnosis or treatment of inflammatory processes, which requires the efficient internalization of the nanoparticles into the cells of interest. Here, we compare novel monodispersed silica-coated iron oxide nanoparticles with commercially available dextran-coated iron oxide nanoparticles. The silica-coated iron oxide nanoparticles displayed excellent magnetic properties. Furthermore, they were non-toxic to primary human monocyte-derived macrophages at all doses tested whereas dose-dependent toxicity of the smaller silica-coated nanoparticles (30 nm and 50 nm) was observed for primary monocyte-derived dendritic cells, but not for the similarly small dextran-coated iron oxide nanoparticles. No macrophage or dendritic cell secretion of pro-inflammatory cytokines was observed upon administration of nanoparticles. The silica-coated iron oxide nanoparticles were taken up to a significantly higher degree when compared tognificantly higher degree when compared to the dextran-coated nanoparticles, irrespective of size. Cellular internalization of the silica-coated nanoparticles was through an active, actin cytoskeleton-dependent process. We conclude that these novel silica-coated iron oxide nanoparticles are promising materials for medical imaging, cell tracking and other biomedical applications.

  20. Antimicrobial activity of silica coated silicon nano-tubes (SCSNT) and silica coated silicon nano-particles (SCSNP) synthesized by gas phase condensation.

    Science.gov (United States)

    Tank, Chiti; Raman, Sujatha; Karan, Sujoy; Gosavi, Suresh; Lalla, Niranjan P; Sathe, Vasant; Berndt, Richard; Gade, W N; Bhoraskar, S V; Mathe, Vikas L

    2013-06-01

    Silica-coated, silicon nanotubes (SCSNTs) and silica-coated, silicon nanoparticles (SCSNPs) have been synthesized by catalyst-free single-step gas phase condensation using the arc plasma process. Transmission electron microscopy and scanning tunneling microscopy showed that SCSNTs exhibited a wall thickness of less than 1 nm, with an average diameter of 14 nm and a length of several 100 nm. Both nano-structures had a high specific surface area. The present study has demonstrated cheaper, resistance-free and effective antibacterial activity in silica-coated silicon nano-structures, each for two Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) was estimated, using the optical densitometric technique, and by determining colony-forming units. The MIC was found to range in the order of micrograms, which is comparable to the reported MIC of metal oxides for these bacteria. SCSNTs were found to be more effective in limiting the growth of multidrug-resistant Staphylococcus aureus over SCSNPs at 10 ?g/ml (IC 50 = 100 ?g/ml). PMID:23494617

  1. Synthesis and characterization of core-shell Fe3O4-gold-chitosan nanostructure

    Directory of Open Access Journals (Sweden)

    Salehizadeh Hossein

    2012-01-01

    Full Text Available Abstract Background Fe3O4-gold-chitosan core-shell nanostructure can be used in biotechnological and biomedical applications such as magnetic bioseparation, water and wastewater treatment, biodetection and bioimaging, drug delivery, and cancer treatment. Results Magnetite nanoparticles with an average size of 9.8 nm in diameter were synthesized using the chemical co-precipitation method. A gold-coated Fe3O4 monotonous core-shell nanostructure was produced with an average size of 15 nm in diameter by glucose reduction of Au3+ which is then stabilized with a chitosan cross linked by formaldehyde. The results of analyses with X-ray diffraction (XRD, Fourier Transformed Infrared Spectroscopy (FTIR, Transmission Electron Microscopy (TEM, and Atomic Force Microscopy (AFM indicated that the nanoparticles were regularly shaped, and agglomerate-free, with a narrow size distribution. Conclusions A rapid, mild method for synthesizing Fe3O4-gold nanoparticles using chitosan was investigated. A magnetic core-shell-chitosan nanocomposite, including both the supermagnetic properties of iron oxide and the optical characteristics of colloidal gold nanoparticles, was synthesized.

  2. Synthesis, characterization and magnetic properties of Fe3O4 doped chitosan polymer

    Science.gov (United States)

    Karaca, E.; ?at?r, M.; Kazan, S.; Aç?kgöz, M.; Öztürk, E.; Gürda?, G.; Uluta?, D.

    2015-01-01

    Fe3O4 nanoparticles doped into chitosan films were prepared by the solution casting technique. Various samples were synthesized in atmospheric medium and in vacuum. The morphological properties of the samples were characterized by high resolution transmission electron microscopy (HR-TEM) and Scanning Electron Microscopy (SEM). The structural, magnetic, and microwave absorption properties of magnetic chitosan films have been carried out using the Vibrating Sample Magnetometer (VSM) and Ferromagnetic Resonance (FMR). It is shown that the composite polymer behaves like a superparamagnetic material with high blocking temperature. The effective magnetization shows gradual increments with the concentration of dopant Fe3O4 nanoparticles. The microwave absorption characteristic of superparamagnetic composite polymer shows low reflection loss.

  3. Hyperthermia HeLa cell treatment with silica coated manganese oxide nanoparticles

    CERN Document Server

    Villanueva, A; Alonso, JM; Rueda, T; Martínez, A; Crespo, P; Morales, MP; Fernandez, MA Gonzalez; Valdes, J; Rivero, G

    2009-01-01

    HeLa tumour cells incubated with ferromagnetic nanoparticles of manganese oxide perovskite La0.56(SrCa)0.22MnO3 were treated with a high frequency alternating magnetic field. The particles were previously coated with silica to improve their biocompatibility. The control assays made with HeLa tumour cells showed that cell survival and growth rate were not affected by the particle internalization in cells, or by the electromagnetic field on cells without nanoparticles. The application of an alternating electromagnetic field to cells incubated with this silica coated manganese oxide induced a significant cellular damage that finally lead to cell death by an apoptotic mechanism.

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

    OpenAIRE

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

    2013-01-01

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

  5. A comparative study on the structural, optical and magnetic properties of Fe3O4 and Fe3O4@SiO2 core-shell microspheres along with an assessment of their potentiality as electrochemical double layer capacitors.

    Science.gov (United States)

    Majumder, S; Dey, S; Bagani, K; Dey, S K; Banerjee, S; Kumar, S

    2015-04-28

    Herein, we report a comprehensive and comparative study on the crystal structure, and microstructural, optical, magnetic, hyperfine and electrochemical properties of Fe3O4 microspheres (S1) of diameter ?418 nm and Fe3O4@SiO2 core-shell microspheres (S2) of diameter ?570 nm. Each asymmetric unit of the crystalline Fe3O4 has one cation vacancy at the octahedral [B] site. At 300 K the saturation magnetization and coercivity of ferrimagnetically ordered S1 and S2 are 63.5, 38.5 emu g(-1) and 200 and 120 Oe, respectively. We have shown that the synthesis procedure, morphology, surface properties, interparticle interaction manifesting the collective properties of the nanoparticle assembly and the average size of individual Fe3O4 nanoparticles forming the spherical ensemble play a crucial role in determining the magnetic properties of Fe3O4 and Fe3O4@SiO2 microspheres while the diameter of the microsphere does not have significant influence on magnetic properties of such a system. Further, the photoluminescence intensity of Fe3O4 microspheres gets significantly enhanced upon SiO2 coating. A cyclic voltammetric study suggests that S1 can act as a good electrical double layer capacitor (EDLC) above a scan rate of 0.04 V s(-1) while S2 exhibits excellent performance as EDLC in a scan range from 0.01 to 0.06 V s(-1). Thus, S2 is a potential candidate for fabrication of EDLCs. PMID:25787350

  6. Hybrid silica coated magnetic nanoparticles decorated with gold.

    Czech Academy of Sciences Publication Activity Database

    Koktan, Jakub; Kaman, Ond?ej; Veverka, Miroslav; Veverka, Pavel; Herynek, V.; ?ezanka, P.

    Dresden : Technische Universität, 2014. s. 98-98. [International Conference on the Scientific and Clinical Applications of Magnetic Carriers /10./. 10.06.2014-14.06.2014, Dresden] R&D Projects: GA MPO FR-TI3/521; GA ?R(CZ) GAP108/11/0807 Institutional support: RVO:68378271 Keywords : magnetic nanoparticles * cobalt-zinc ferrite * silica encapsulation * manganite perovskites * gold decoration Subject RIV: BM - Solid Matter Physics ; Magnetism

  7. Chemical vapor deposition prepared bi-morphological carbon-coated Fe3O4 composites as anode materials for lithium-ion batteries

    Science.gov (United States)

    Wang, Junhua; Gao, Mingxia; Wang, Dingsheng; Li, Xiang; Dou, Yibo; Liu, Yongfeng; Pan, Hongge

    2015-05-01

    Carbon coated Fe3O4 composite (Fe3O4@C) with bi-morphological architecture has been prepared via a chemical vapor deposition at 450 °C from Fe2O3 nanoparticles by using acetylene as the deposition vapor and carbon source. The Fe2O3 are fully reduced to Fe3O4 in a 10 min of deposition, showing submicron-sized octahedral Fe3O4 particles coated partially with a thin carbon layer mainly, and a few nano-sized Fe3O4 particles coated with carbon also. The deposition period of 20 min results in a further growth of the octahedral Fe3O4 particles and a reduction of the number of the nano-sized ones, correlating to a thick and fully coated carbon layer. Impurities of iron carbides generate in the composite with further prolonging the deposition to 30 min. The Fe3O4@C composite from 20 min of deposition shows superior electrochemical property to others. An initial reversible capacity of 570 mAh g-1 is obtained and the capacity fading is less than 5% after 60 cycles. The fabrication method is facile and time-saving. Such submicron size-predominated Fe3O4@C composite is hopefully not only favorable in alleviating the agglomeration of the iron oxide during cycling, but also helpful in getting high packing density of the anode material.

  8. Studies on interaction and illumination damage of CS-Fe3O4-ZnS:Mn to bovine serum albumin

    International Nuclear Information System (INIS)

    In this study, the interaction of chitosan (CS) coated CS-Fe3O4-ZnS:Mn magnetic-fluorescent nanoparticles (MFNPs) with bovine serum albumin (BSA) was studied by means of ultraviolet–visible and fluorescence spectra; evidences for the damage of BSA molecule in the presence of CS-Fe3O4-ZnS:Mn MFNPs under UV illumination were also obtained. The results show that the dominating fluorescence quenching mechanism of CS-Fe3O4-ZnS:Mn MFNPs with BSA belongs to static quenching. Fluorescence resonance energy transfer (FRET) occurred from BSA to CS-Fe3O4-ZnS:Mn MFNPs. The thermodynamic parameters indicated that electrostatic interaction play major roles in CS-Fe3O4-ZnS:Mn-BSA, while binding processes exist spontaneously. In addition, the damage of CS-Fe3O4-ZnS:Mn MFNPs to BSA molecule under UV illumination was studied under various experimental parameters. It was proved that: the damage of BSA is prone to happen in the presence of CS-Fe3O4-ZnS:Mn MFNPs under UV illumination, there is synergic effect of oxygen and UV illumination on the damage of BSA, and the fluorescence quenching of BSA by CS-Fe3O4-ZnS:Mn MFNPs under UV illumination is mainly a result of a photo-induced free radical procedure.

  9. Synthesis, characterization and application studies of self-made Fe3O4/PES nanocomposite membranes in microbial fuel cell

    International Nuclear Information System (INIS)

    Highlights: ? In this study, a novel, potentially low-priced PEM using nano-size particles of Fe3O4 was used as alternative for proton exchange membrane in microbial fuel cell (MFC). ? Fe3O4 nanoparticles were prepared by co precipitation of iron chloride salts with sodium hydroxide. ? The new synthesized PEM and Nafion 117 were tested in MFC. ? The power density with the new synthesized membrane of Fe3O4 was 29% more than what has been achieved with Nafion as PEM in MFC. - Abstract: Nanocomposite membranes are a promising alternative for proton exchange membrane (PEM) because it has the capability of transferring protons, is inexpensive, and also have higher resistance against fouling compared to other membranes in microbial fuel cells (MFCs). In this study, Saccharomyces cerevisiae was used as an active biocatalyst and neutral red with low concentration (200 ?mol l?1) was selected as electron shuttle in anode chamber. Moreover, four different concentrations of Fe3O4/PES have been tested as new generation of nanocomposite membrane and its efficiencies were compared with Nafion 117 in dual chamber MFC. To improve the performance of PEM, several nanoparticle (5%, 10%, 15% and 20% of Fe3O4 nanoparticle) concentrations were used. Maximum generated power and current with new synthesized membrane and 15% Fe3O4 nanoparticlO4 nanoparticle were 20 mW m?2 and 148 mA m?2, while it was 15.4 mW m?2 and 112 mA m?2, respectively by using Nafion 117 at the same experimental condition. The highest obtained voltage was 656 mV and it was stable for 72 h of operation time.

  10. Scalable preparation of ultrathin silica-coated Ag nanoparticles for SERS application.

    Science.gov (United States)

    Hu, Yanjie; Shi, Yunli; Jiang, Hao; Huang, Guangjian; Li, Chunzhong

    2013-11-13

    Silica-coated Ag nanoparticles (Ag@SiO2 NPs) have been successfully prepared by a scalable flame spray pyrolysis (FSP) technique with production rate up to 4 g/h in laboratory-scale. The ultrathin SiO2 shell, with a thickness 1 nm, not only effectively avoids the intersintering of Ag nanoparticles core at the high temperature, but also serves as a protective layer of the SERS-active nanostructure. The silica-coated Ag nanoparticles form agglomerates in the large temperature gradient zone, which with several nanometers gaps from each other but not contact. Such an intriguing feature can result in more Raman hot-spots generated at the gaps among Ag core active sites, which will beneficial for the whole SERS substrate enhancement. The results demonstrate that a maximum enhancement factor can reach ~10(5) with a detectable concentration as low as 10(-10) M for rhodamine 6G (R6G) molecules, indicating that the as-obtained unique nanostructure will be a promising candidate for SERS applications. PMID:24117322

  11. Enhanced hydrogen adsorption by Fe3O4-graphene oxide materials

    Science.gov (United States)

    Moradi, Seyyed Ershad

    2015-04-01

    In the present work, graphene oxide (GO) was prepared by hummers method from natural graphite and modified with iron oxide nanoparticles. The structural order and textural properties of the graphene-based materials were studied by TEM, XRD, TG-DTA and FT-IR. Hydrogen adsorption measurements have been carried out at 77 or 87 K, and atmospheric pressure on graphene oxide and Fe3O4-graphene oxide materials. Hydrogen adsorption at 77 K and atmospheric pressure reached values in the order of 1.7 and 2.1 wt% for graphene oxide and Fe3O4-graphene oxide materials, respectively. The hydrogen adsorption capacities of the Fe3O4-graphene oxide materials compare favorably well with those attained with high-value carbon materials. The isosteric heat of adsorption ( Q st) was investigated as a function of hydrogen uptake at 77 and 87 K over the pressure range of 0 to atmospheric pressure. The isosteric heat of adsorption for magnetic GO (9.7 kJ mol-1) was found to be higher than for GO (6.1 kJ mol-1).

  12. One-pot green synthesis of reduced graphene oxide (RGO)/Fe3O4 nanocomposites and its catalytic activity toward methylene blue dye degradation

    Science.gov (United States)

    Vinothkannan, M.; Karthikeyan, C.; Gnana kumar, G.; Kim, Ae Rhan; Yoo, Dong Jin

    2015-02-01

    The reduced graphene oxide (RGO)/Fe3O4 nanocomposites were synthesized through a facile one-pot green synthesis by using solanum trilobatum extract as a reducing agent. Spherical shaped Fe3O4 nanoparticles with the diameter of 18 nm were uniformly anchored over the RGO matrix and the existence of fcc structured Fe3O4 nanoparticles over the RGO matrix was ensured from X-ray diffraction patterns. The amide functional groups exist in the solanum trilobatum extract is directly responsible for the reduction of Fe3+ ions and GO. The thermal stability of GO was increased by the removal of hydrophilic functional groups via solanum trilobatum extract and was further promoted by the ceramic Fe3O4 nanoparticles. The ID/IG ratio of RGO/Fe3O4 was increased over GO, indicating the extended number of structural defects and disorders in the RGO/Fe3O4 composite. The catalytic efficiency of prepared nanostructures toward methylene blue (MB) dye degradation mediated through the electron transfer process of BH4- ions was studied in detail. The ?-? stacking, hydrogen bonding and electrostatic interaction exerted between the RGO/Fe3O4 composite and methylene blue, increased the adsorption efficiency of dye molecules and the large surface area and extended number of active sites completely degraded the MB dye within 12 min.

  13. Synthesis and characterization of Ag/Fe3O4 electromagnetic shielding particles

    International Nuclear Information System (INIS)

    Ag/Fe3O4 nano-composites are synthesized by electroless silver plating technique and characterized by X-ray diffraction, scanning/transmission electron microscope, magnetic measurement equipment and vector network analyzer. They show the silver layer coated on the surface of the particles successfully, and which can enhance the dielectricity and permeability properties of the ferromagnetic particles. The dielectric loss values of the composites are more than 1.0 in the almost whole test frequency range and the imaginary part of permeability of Ag/Fe3O4 is higher than real part in 2–5 GHz. The value of Hc is increased to 165.2 Oe due to the extended relaxation time of magnetic domain deflection of the magnetic powders which covered by silver layer. And the calculated microwave loss is more than 20 dB in the whole frequency range. As a result, the Ag/Fe3O4 nano-composites are expected to be used as electromagnetic shielding particle material in multiband smoke agent. - Highlights: • Due to the decoration of silver nano-particles, the inorganic magnetic composite particle shows excellent dielectric loss in the almost whole test frequency range and good magnetic loss at 2 GHz to 5 GHz, especially the particle also has infrared reflection characteristic. • The well-performed obstacle Ag/Fe3O4 particles will be expected to be used as electromagnetic shielding particles in multiband smoke agent to improve the IR and electromagnetic interference performance of the smoke screen

  14. Synthesis and Characterization of Rice Straw/Fe3O4 Nanocomposites by a Quick Precipitation Method

    Directory of Open Access Journals (Sweden)

    Katayoon Kalantari

    2013-06-01

    Full Text Available Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O, ferrous chloride (FeCl2·4H2O, sodium hydroxide (NaOH and urea (CH4N2O were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray fluorescence (EDXF and Fourier transforms infrared spectroscopy (FT?IR. The rice straw/Fe3O4-NCs prepared by this method have magnetic properties.

  15. A solvothermal method to produce RGO-Fe3O4 hybrid composite for fast chromium removal from aqueous solution

    International Nuclear Information System (INIS)

    A simple one step solvotermal strategy using non-toxic and cost-effective precursors has been developed to prepare reduced graphene oxide (RGO)-Fe3O4 non-nanocomposite for removal of Cr(VI). Compared with the nano-adsorbent, the RGO-Fe3O4 hybrid particles with size larger than 100 nm can reduce cell toxicity in water treatment processes. The structure, surface and magnetic characteristics of the non-nanocomposite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and Vibrating sample magnetometer (VSM). The RGO-Fe3O4 composite with the highest loading of Fe3O4 demonstrates the fastest removal of 500 ?g/L Cr(VI) which can reach 85% within 5 min at neutral pH. The adsorption kinetics follows the pseudo-second-order model and the adosorbent exhibits better Cr(VI) removal efficiency in water at low pH. However, the removal efficiency of Cr(VI) decreased when common hazardous ions were added in water. The large saturation magnetization (41.12 emu/g) of the synthesized non-nanoparticles allows fast separation of the adsorbent from water. The RGO-Fe3O4 non-nanocomposite could be utilized as an efficient, stable, less toxic and magnetically separable adsorbent for environmental cleanup.

  16. New insight on optical and magnetic Fe3O4 nanoclusters promising for near infrared theranostic applications.

    Science.gov (United States)

    Huang, Chih-Chia; Chang, Po-Yang; Liu, Chien-Liang; Xu, Jia-Pu; Wu, Shu-Pao; Kuo, Wen-Chuan

    2015-08-01

    Extensive efforts have been devoted to the development of a new biophotonic system using near infrared (NIR) nano-agents for non-invasive cancer diagnosis and therapy. Here, we developed a simple synthesis reaction of ligands, hydrazine, and iron(ii) chloride to fabricate Fe3O4 cluster-structured nanoparticles (CNPs) with interesting NIR photonics and high magnetization (Ms: 98.3 emu g(-1) and proton relaxivity r2: 234.6 mM(-1) s(-1)). These Fe3O4 CNPs exhibited optical absorption and reflection over all wavelengths, showing a U-shape absorption band with a low absorbance at a range of 750-950 nm and a progressive evolution in the second near infrared region. Strengthening of the scattering effect by incubating Fe3O4 CNPs with HeLa cells was observed when optical contrast enhancement was performed in an optical coherence tomography (OCT) microscope system with a laser light source at 860 nm. Using a 1064 nm laser at a low power density (380 mW cm(-2)) to excite the Fe3O4 CNPs (375 ppm[Fe]) led to a rise in the water temperature from 25 °C to 58 °C within 10 min. Finally, we present the first example of magnetomotive OCT cellular imaging combined with enhanced photothermal therapy using Fe3O4 CNPs and applying a magnetic field, which is promising for preclinical and clinical trials in the future. PMID:26151814

  17. Synthesis of three-dimensional network Fe3O4 at gas/liquid interface and its sensing application

    International Nuclear Information System (INIS)

    When free diffusing ammonia begins to dissolve into a reaction precursor solution, a gas/liquid interface formed. Three-dimensional (3D) network iron oxide (i-Fe3O4) was synthesized at the interface without the protection of any inert gas at room temperature. This is the first time ammonia vapor method be used to prepare nano iron oxide at a gas/liquid interface. Scanning electron microscope results of it indicated that 3D network i-Fe3O4 is an assembly of nanowires and its properties are quite similar to spherical Fe3O4 nanoparticle. Energy dispersive X-ray spectroscopy, X-ray diffraction and Fourier transform infrared spectra were used to confirm the presence of Fe3O4. Electrochemical methods were employed to investigate the sensing properties for the electrocatalytic oxidation of hydrazine hydrate at the i-Fe3O4/glassy carbon electrode (GCE). The sensor displayed a response time less than 2 s, a sensitivity of 152 ?A mM?1 cm?2 and the linearity of 0.1 to 600 ?M with a detection limit of 0.05 ?M (S/N = 3).

  18. Molecular dynamics study on Au/Fe3O4 nanocomposites and their surface function toward amino acids.

    Science.gov (United States)

    Yue, Jeffrey; Jiang, Xuchuan; Yu, Aibing

    2011-10-13

    The deposition of gold nanoparticles on the magnetite (Fe(3)O(4)) surface is demonstrated through a molecular dynamics method. The simulated results show that an intermediate layer composed by such as a surfactant, polymer, or silica plays a key role in the formation of core/shell Fe(3)O(4)/Au nanostructures. The functional groups of the intermediate layer are crucial factors in depositing gold onto the Fe(3)O(4) surface via nonbonding interactions, in which the van der Waals and columbic forces will determine the strength of interaction toward the gold and iron oxide. Such interactions can affect the stability of the metal-coated nanocomposites and hence the functional properties. The nanocomposite is further investigated on the surface adsorption of amino acids (e.g., cysteine), which may be useful for functional exploration in biomedical applications. PMID:21894978

  19. SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF A Fe3O4/C12 CORE/SHELL NANOSYSTEM

    Directory of Open Access Journals (Sweden)

    Alexandru Mihai Grumezescu

    2012-06-01

    Full Text Available Lauric acid (C12 functionalized Fe3O4 nanoparticles were fabricated and characterized by XRD, FT-IR, DTA-TG and TEM. Lauric acid was used as a coating agent, controlling particle size and aggregation during the synthesis. XRD confirms the formation of magnetite. FT-IR evidenced the successful surface fictionalization with C12, peaks assigned to lauric acid being identified in the nanopowder. The obtained core/shell nanostructure consists of spherical particles of several nanometers long, according to TEM characterization. The interaction with HEp2 cell line proved that Fe3O4/C12 nanostructures are biocompatible.

  20. Rapid degradation of methylene blue in a novel heterogeneous Fe3O4?@rGO@TiO2-catalyzed photo-Fenton system

    Science.gov (United States)

    Yang, Xiaoling; Chen, Wei; Huang, Jianfei; Zhou, Ying; Zhu, Yihua; Li, Chunzhong

    2015-01-01

    Herein, a ternary nanocomposite with TiO2 nanoparticles anchored on reduced graphene oxide (rGO)-encapsulated Fe3O4 spheres (Fe3O4@rGO@TiO2) is presented as a high efficient heterogeneous catalyst for photo-Fenton degradation of recalcitrant pollutants under neutral pH. Fe3O4@rGO@TiO2 was synthesized by depositing TiO2 nanoparticles on the surface of the Fe3O4 spheres wrapped by graphene oxide (GO) which was obtained by an electrostatic layer-by-layer method. This as-prepared catalyst reflected good ferromagnetism and superior stability which makes it convenient to be separated and recycled. Due to the synergic effects between the different components composed the catalyst, swift reduction of Fe3+ can be achieved to regenerate Fe2+. Fe3O4@rGO@TiO2 exhibited enhancing catalytic activity for the degradation of azo-dyes compared with Fe3O4, Fe3O4@SiO2@TiO2 or SiO2@rGO@TiO2, further conforming the rapid redox reaction between Fe2+ and Fe3+. All these merits indicate that the composite catalyst possesses great potential for visible-light driven destruction of organic compounds. PMID:26000975

  1. One-dimensional assemblies of silica-coated cobalt nanoparticles: Magnetic pearl necklaces

    Energy Technology Data Exchange (ETDEWEB)

    Salgueirino-Maceira, Veronica [Instituto de Investigacions Tecnoloxicas, Universidade de Santiago de Compostela, 15782 (Spain) and Department of Electrical Engineering, Arizona State University, Tempe, AZ (United States)]. E-mail: vsalgue@usc.es; Correa-Duarte, Miguel A. [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ (United States); Hucht, Alfred [Fachbereich Physik, Universitaet Duisburg-Essen, D-47048 Duisburg (Germany); Farle, Michael [Fachbereich Physik, Universitaet Duisburg-Essen, D-47048 Duisburg (Germany)

    2006-08-15

    Silica-coated cobalt nanoparticles were found to organize into chains when driven by a weak external magnetic field. Strong dipole-dipole magnetic interactions are believed to be the driving force of the self-organization once the cobalt nanoparticles undergo the superparamagnetic to ferromagnetic (SP-FM) transition, as increasing their size during the synthesis process. The method, although simple, produces structures resembling pearl necklace-like structures, comparable to one-dimensional species obtained in more laborious processes. Molecular dynamic simulations taking magnetic dipolar forces into account reproduce the observed self-assembled structures. The nanoscale engineering of this type of colloids is expected to extend the spectrum of magnetic effects and functionalities.

  2. One-dimensional assemblies of silica-coated cobalt nanoparticles: Magnetic pearl necklaces

    International Nuclear Information System (INIS)

    Silica-coated cobalt nanoparticles were found to organize into chains when driven by a weak external magnetic field. Strong dipole-dipole magnetic interactions are believed to be the driving force of the self-organization once the cobalt nanoparticles undergo the superparamagnetic to ferromagnetic (SP-FM) transition, as increasing their size during the synthesis process. The method, although simple, produces structures resembling pearl necklace-like structures, comparable to one-dimensional species obtained in more laborious processes. Molecular dynamic simulations taking magnetic dipolar forces into account reproduce the observed self-assembled structures. The nanoscale engineering of this type of colloids is expected to extend the spectrum of magnetic effects and functionalities

  3. Rose-like Pd-Fe3O4 hybrid nanocomposite-supported Au nanocatalysts for tandem synthesis of 2-phenylindoles.

    Science.gov (United States)

    Woo, Hyunje; Park, Ji Chan; Park, Sungkyun; Park, Kang Hyun

    2015-04-30

    A facile synthesis of rose-like Pd-Fe3O4 nanocomposites via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(OAc)2, followed by the immobilization of Au nanoparticles (NPs) onto the Pd-Fe3O4 supports, is reported. The morphology of these hybrid nanostructures could be easily controlled by varying the amount of Fe(CO)5 and the reaction temperature. Moreover, the synthesized Au/Pd-Fe3O4 catalyst exhibited high catalytic activity for the tandem synthesis of 2-phenylindoles and demonstrated magnetic recyclability. PMID:25901692

  4. Synthesis of a novel carbon network-supported Fe3O4@C composite and its applications in high-power lithium-ion batteries

    International Nuclear Information System (INIS)

    A polymer carbonization route was designed to synthesis carbon network-supported Fe3O4@C composites. The Fe3O4 nanoparticles with an average of ?200 nm were uniformly wrapped up in this novel carbon network. As an anode material for rechargeable lithium-ion batteries, the Fe3O4@C composites present attractive properties with a high specific capacity of 730 mAh g?1 at 2 C after 300 cycles. The novel carbon network plays a key role in enhancing the electrochemical performance of the composites

  5. Magnetically Separable and Recyclable Fe3O4-Supported Ag Nanocatalysts for Reduction of Nitro Compounds and Selective Hydration of Nitriles to Amides in Water

    Directory of Open Access Journals (Sweden)

    Hyunje Woo

    2014-01-01

    Full Text Available As hybrid nanostructures have become more important in many fields of chemistry, Ag nanoparticles (NPs are being increasingly immobilized onto Fe3O4 microspheres in situ. Structural characterization reveals that the Ag NPs are uniformly immobilized in the Fe3O4 microsphere-based supports. Moreover, Ag NPs are more stable in the hybrid structure than in the naked state and show high catalytic activity for the reduction of nitro compounds and hydration of nitriles to amides in water. The Fe3O4 microspheres were recycled several times using an external magnet.

  6. Charge and complex orbital ordering in Fe3O4

    International Nuclear Information System (INIS)

    To discuss charge and orbital ordering in magnetite (Fe3O4), a spinless three-band Hubbard model was investigated by the exact diagonalization of finite size clusters and the Hartree-Fock approximation. A state with noncollinear orbital moments is obtained with both the methods. The orbital moments are not induced by the ordered spin moment via the spin-orbit interaction as usual magnetic materials but by spontaneous breaking of the time reversal symmetry within the orbital degrees of freedom. The result is consistent with a large orbital moment found in the measurements of the magnetic circular dichroism of Fe 2p X-ray absorption spectra

  7. Multifunctional Au-Fe3O4@MOF core-shell nanocomposite catalysts with controllable reactivity and magnetic recyclability

    Science.gov (United States)

    Ke, Fei; Wang, Luhuan; Zhu, Junfa

    2014-12-01

    The recovery and reuse of expensive catalysts are important in both heterogeneous and homogeneous catalysis due to economic and environmental reasons. This work reports a novel multifunctional magnetic core-shell gold catalyst which can be easily prepared and shows remarkable catalytic properties in the reduction of 4-nitrophenol. The novel Au-Fe3O4@metal-organic framework (MOF) catalyst consists of a superparamagnetic Au-Fe3O4 core and a porous MOF shell with controllable thickness. Small Au nanoparticles (NPs) of 3-5 nm are mainly sandwiched between the Fe3O4 core and the porous MOF shell. Catalytic studies show that the core-shell structured Au-Fe3O4@MOF catalyst has a much higher catalytic activity than other reported Au-based catalysts toward the reduction of 4-nitrophenol. Moreover, this catalyst can be easily recycled due to the presence of the superparamagnetic core. Therefore, compared to conventional catalysts used in the reduction of 4-nitrophenol, this porous MOF-based magnetic catalyst is green, cheap and promising for industrial applications.The recovery and reuse of expensive catalysts are important in both heterogeneous and homogeneous catalysis due to economic and environmental reasons. This work reports a novel multifunctional magnetic core-shell gold catalyst which can be easily prepared and shows remarkable catalytic properties in the reduction of 4-nitrophenol. The novel Au-Fe3O4@metal-organic framework (MOF) catalyst consists of a superparamagnetic Au-Fe3O4 core and a porous MOF shell with controllable thickness. Small Au nanoparticles (NPs) of 3-5 nm are mainly sandwiched between the Fe3O4 core and the porous MOF shell. Catalytic studies show that the core-shell structured Au-Fe3O4@MOF catalyst has a much higher catalytic activity than other reported Au-based catalysts toward the reduction of 4-nitrophenol. Moreover, this catalyst can be easily recycled due to the presence of the superparamagnetic core. Therefore, compared to conventional catalysts used in the reduction of 4-nitrophenol, this porous MOF-based magnetic catalyst is green, cheap and promising for industrial applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05421k

  8. Fabrication and characterization of superparamagnetic poly(vinyl pyrrolidone)/poly(L-lactide)/Fe3O4 electrospun membranes

    Science.gov (United States)

    Savva, Ioanna; Constantinou, Demetris; Marinica, Oana; Vasile, Eugeniu; Vekas, Ladislau; Krasia-Christoforou, Theodora

    2014-02-01

    The fabrication of magnetoactive fibrous nanocomposite membranes based on poly(vinyl pyrrolidone) (PVP), poly(L-lactide) (PLLA) and pre-formed oleic acid coated magnetite nanoparticles (OA Fe3O4) is presented. The aforementioned materials have been prepared by means of the electrospinning technique following a single-step fabrication process. The PVP/PLLA/OA Fe3O4 nanocomposite membranes were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that provided information on the fiber diameters as well as on the morphological and dimensional characteristics of the OA Fe3O4 nanoparticles embedded within the fibers. The thermal stability of these materials was evaluated by means of thermal gravimetric analysis (TGA) measurements. Finally, vibrational sample magnetometry (VSM) analysis disclosed superparamagnetic behavior at room temperature. The combination of the hydrophilic, biocompatible and photo-crosslinkable PVP with the biodegradable PLLA and the superparamagnetic OA Fe3O4 nanoparticles within these materials allows for the future development of crosslinked fibrous magnetoactive nanocomposites exhibiting high stability in aqueous solutions, with potential use in biomedical and environmental applications.

  9. Fabrication, characterization and application in electromagnetic wave absorption of flower-like ZnO/Fe3O4 nanocomposites

    International Nuclear Information System (INIS)

    Large-quantity flower-like tubular ZnO coated with Fe3O4 nanoparticles were synthesized via a simple solution method at low temperature. The phase structures and morphologies of the composite had been characterized by XRD and FESEM. The results showed that Fe3O4 nanoparticles coating on flower-like tubular ZnO can be obtained at 90 deg. C. The structure of flower-like tubular ZnO was not destroyed in the coating process. The test of electromagnetic wave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. Magnetic measurements revealed the presence of magnetite nanoparticles in the composites. Measurements of the electromagnetic parameters of the samples showed that the flower-like tubular ZnO/Fe3O4 nanocomposites were much better than the pure ZnO or Fe3O4 with the efficiency of electromagnetic wave absorption.

  10. Facile synthesis of QD-anchored composite particles with magnetite cluster cores (nFe3O4@SiO2@QDs)

    International Nuclear Information System (INIS)

    Highlights: ? Triple layered Fe3O4/SiO2/QDs were designed as fluorescent magnetic nanocomposites. ? Magnetite cluster-embedded silica exhibited strong and controllable magnetism. ? Effective conjugation between QDs and magnetic silica occurred at pH3. - Abstract: Magnetism-controlled fluorescent composite particles (nFe3O4@SiO2@QDs) were prepared as QD-anchored silica nanoparticles with magnetite cluster cores. First, citrate-capped magnetites (C-Fe3O4) were prepared by the co-precipitation method and subsequently complexed with 3-aminopropyl-trimethoxysilane (APTMS) at room temperature, consequently leading to the formation of magnetite clusters (A-nFe3O4) with alkoxy terminated interfaces. The sol–gel reaction between A-nFe3O4 and tetraethoxysilane (TEOS) produced the core-shell nFe3O4@SiO2. The resulting core-shell particles exhibited superparamagnetic properties and controllable magnetism simply by adjusting the thickness of nonmagnetic silica layer. After then, amine-terminated nFe3O4@SiO2 (NH2–nFe3O4@SiO2) was conjugated with carboxy quantum dots (QDs) using an EDC coupling agent. The QD conjugation with NH2–2 of lower pH exhibited the higher photoluminescence (PL) intensity, and the resulting composite particles (nFe3O4@SiO2@QDs) can be a useful biomedical agent. This chemical strategy can be further applied to prepare the core-shell magnetic nanostructure with various oxide layers for specific applications

  11. Sol–gel derived silica/chitosan/Fe3O4 nanocomposite for direct electrochemistry and hydrogen peroxide biosensing

    Science.gov (United States)

    Satvekar, R. K.; Rohiwal, S. S.; Tiwari, A. P.; Raut, A. V.; Tiwale, B. M.; Pawar, S. H.

    2015-01-01

    A novel strategy to fabricate hydrogen peroxide third generation biosensor has been developed from sol–gel of silica/chitosan (SC) organic–inorganic hybrid material assimilated with iron oxide magnetic nanoparticles (Fe3O4). The large surface area of Fe3O4 and porous morphology of the SC composite facilitates a high loading of horseradish peroxidase (HRP). Moreover, the entrapped enzyme preserves its conformation and biofunctionality. The fabrication of hydrogen peroxide biosensor has been carried out by drop casting of the SC/F/HRP nanocomposite on glassy carbon electrode (GCE) for study of direct electrochemistry. The x-ray diffraction (XRD) pattern and transmission electron microscopy (TEM) confirms the phase purity and particle size of as-synthesized Fe3O4 nanoparticles, respectively. The nanocomposite was characterized by UV–vis spectroscopy, fluorescence spectroscopy and Fourier transform infrared (FTIR) for the characteristic structure and conformation of enzyme. The surface topographies of the nanocomposite thin films were investigated by scanning electron microscopy (SEM). Dynamic light scattering (DLS) was used to determine the particle size distribution. The electrostatic interactions of the SC composite with Fe3O4 nanoparticles were studied by the zeta potential measurement. Electrochemical impedance spectroscopy (EIS) of the SC/F/HRP/GCE electrode displays Fe3O4 nanoparticles as an excellent candidate for electron transfer. The SC/F/HRP/GCE exhibited a pair of well-defined quasi reversible cyclic voltammetry peaks due to the redox couple of HRP-heme Fe (III)/Fe (II) in pH 7.0 potassium phosphate buffer. The biosensor was employed to detect H2O2 with linear range of 5 ?M to 40 ?M and detection limit of 5 ?M. The sensor displays excellent selectivity, sensitivity, good reproducibility and long term stability.

  12. Inorganic-organic elastomer nanocomposites from integrated ellipsoidal silica-coated hematite nanoparticles as crosslinking agents

    International Nuclear Information System (INIS)

    We report on the synthesis of nanocomposites with integrated ellipsoidal silica-coated hematite (SCH) spindle type nanoparticles which can act as crosslinking agents within an elastomeric matrix. Influence of the surface chemistry of the hematite, leading either to dispersed particles or crosslinked particles to the elastomer matrix, was studied via swelling, scattering and microscopy experiments. It appeared that without surface modification the SCH particles aggregate and act as defects whereas the surface modified SCH particles increase the crosslinking density and thus reduce the swelling properties of the nanocomposite in good solvent conditions. For the first time, inorganic SCH particles can be easily dispersed into a polymer network avoiding aggregation and enhancing the properties of the resulting inorganic-organic elastomer nanocomposite (IOEN).

  13. MAPLE Fabricated Fe3O4@Cinnamomum verum Antimicrobial Surfaces for Improved Gastrostomy Tubes

    Directory of Open Access Journals (Sweden)

    Alina Georgiana Anghel

    2014-06-01

    Full Text Available Cinnamomum verum-functionalized Fe3O4 nanoparticles of 9.4 nm in size were laser transferred by matrix assisted pulsed laser evaporation (MAPLE technique onto gastrostomy tubes (G-tubes for antibacterial activity evaluation toward Gram positive and Gram negative microbial colonization. X-ray diffraction analysis of the nanoparticle powder showed a polycrystalline magnetite structure, whereas infrared mapping confirmed the integrity of C. verum (CV functional groups after the laser transfer. The specific topography of the deposited films involved a uniform thin coating together with several aggregates of bio-functionalized magnetite particles covering the G-tubes. Cytotoxicity assays showed an increase of the G-tube surface biocompatibility after Fe3O4@CV treatment, allowing a normal development of endothelial cells up to five days of incubation. Microbiological assays on nanoparticle-modified G-tube surfaces have proved an improvement of anti-adherent properties, significantly reducing both Gram negative and Gram positive bacteria colonization.

  14. MAPLE fabricated Fe3O4@Cinnamomum verum antimicrobial surfaces for improved gastrostomy tubes.

    Science.gov (United States)

    Anghel, Alina Georgiana; Grumezescu, Alexandru Mihai; Chirea, Mariana; Grumezescu, Valentina; Socol, Gabriel; Iordache, Florin; Oprea, Alexandra Elena; Anghel, Ion; Holban, Alina Maria

    2014-01-01

    Cinnamomum verum-functionalized Fe3O4 nanoparticles of 9.4 nm in size were laser transferred by matrix assisted pulsed laser evaporation (MAPLE) technique onto gastrostomy tubes (G-tubes) for antibacterial activity evaluation toward Gram positive and Gram negative microbial colonization. X-ray diffraction analysis of the nanoparticle powder showed a polycrystalline magnetite structure, whereas infrared mapping confirmed the integrity of C. verum (CV) functional groups after the laser transfer. The specific topography of the deposited films involved a uniform thin coating together with several aggregates of bio-functionalized magnetite particles covering the G-tubes. Cytotoxicity assays showed an increase of the G-tube surface biocompatibility after Fe3O4@CV treatment, allowing a normal development of endothelial cells up to five days of incubation. Microbiological assays on nanoparticle-modified G-tube surfaces have proved an improvement of anti-adherent properties, significantly reducing both Gram negative and Gram positive bacteria colonization. PMID:24979402

  15. Electrochemiluminescence immunosensor based on multifunctional luminol-capped AuNPs@Fe3O4 nanocomposite for the detection of mucin-1.

    Science.gov (United States)

    Wang, Jing-Xi; Zhuo, Ying; Zhou, Ying; Yuan, Ruo; Chai, Ya-Qin

    2015-09-15

    In this work, a novel and multifunctional nanocomposite of luminol capped gold modified Fe3O4 (Lu-AuNPs@Fe3O4) was utilized as the carrier of secondary antibody (Ab2) to fabricate a sandwiched electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of mucin-1 (MUC1). Herein, the luminol capped gold nanoparticles (Lu-AuNPs) were synthesized with HAuCl4 and luminol by the help of NaBH4 at room temperature, and then Lu-AuNPs were adsorbed on the Fe3O4 magnetic nanoparticles (MNPs) to form the nanocomposite of Lu-AuNPs@Fe3O4 via electrostatic interaction. Fe3O4 MNPs in Lu-AuNPs@Fe3O4 exhibited excellent conductivity and admirable catalytic activity in H2O2 decomposition, which could enhance the ECL efficiency of luminol-H2O2 system. In addition, the substrates of gold coated ZnO nanoparticles (AuNPs@ZnO), providing large specific surface areas for primary antibody (Ab1) capturing, were modified on the electrode. As a result, a wide linear range of 7 orders of magnitude from 10fg/mL to 10ng/mL was obtained with an ultralow detection limit of 4.5fg/mL for MUC1. PMID:25950936

  16. Copper nanoparticles supported on silica coated maghemite as versatile, magnetically recoverable and reusable catalyst for alkyne coupling and cycloadditon reactions

    OpenAIRE

    Nador, Fabiana; Volpe, María A.; Alonso Valdés, Francisco; Feldhoff, Armin; Kirschning, Andreas; Radivoy, Gabriel

    2012-01-01

    A versatile and magnetically recoverable catalyst consisting of copper nanoparticles on silica coated maghemite nanoparticles (MagSilica®) is presented. The catalyst has been prepared under mild conditions by fast reduction of anhydrous CuCl2 with lithium sand and a catalytic amount of DTBB (4,4’-di-tert-butylbiphenyl) as electron carrier, in the presence of the magnetic support. The catalyst has been fully characterized and its performance in different coupling and cycloaddition reactions of...

  17. Particle-size dependent melt viscosity behavior and the properties of three-arm star polystyrene-Fe3O4 composites.

    Science.gov (United States)

    Tan, Haiying; Lin, Yichao; Zheng, Jun; Gong, Jiang; Qiu, Jian; Xing, Haiping; Tang, Tao

    2015-05-28

    The melt viscosity of three-arm star polystyrene (S3PS)-Fe3O4 nanoparticle composites was studied by means of rheological measurements. The arm molecular weight (Ma) of S3PS (or radius gyration) and the particle size of Fe3O4 (radius (Rp): 3 nm and 44 nm) showed a strong influence on the melt viscosity behavior (at low shear frequencies) of S3PS-Fe3O4 composites. The reinforcement (viscosity increase) was observed in the composites where the Ma was higher than the Mc of PS (Mc: the critical molecular weight for chain entanglement). For Ma properties and thermal stability of S3PS-Fe3O4 composites were studied. PMID:25892158

  18. Facile synthesis of pectin coated Fe3O4 nanospheres by the sonochemical method

    International Nuclear Information System (INIS)

    Pectin coated Fe3O4 magnetic nanospheres (PCMNs) were synthesized by the sonochemical method. The Fe3O4 nanoparticles were prepared by chemical precipitation as reported in the previous articles, and the PCMNs were characterized by transmission electron microscopy, dynamic light scattering, thermogravimetric analysis, Fourier-transform infrared spectroscopy, a vibrating sample magnetometer and energy dispersive X-ray spectrum. The results indicated that the magnetic nanoparticles have been coated by pectin, magnetite content of which was up to 63%, with the saturation magnetization being 32.69 emu/g. The formation mechanism and further application of PCMNs have also been discussed. The results show that the PCMNs can be applied to biomedical applications. -- Highlights: ? Using the sonochemical method to synthesize the pectin coated magnetic nanospheres makes it easier to load the drugs. ? Pectin is difficult to digest and can only be degraded in colon; it has a bright future in colon targeting. ? This method can control the particle size distribution and magnetic content effectively

  19. Rose-like Pd-Fe3O4 hybrid nanocomposite-supported Au nanocatalysts for tandem synthesis of 2-phenylindoles

    Science.gov (United States)

    Woo, Hyunje; Park, Ji Chan; Park, Sungkyun; Park, Kang Hyun

    2015-04-01

    A facile synthesis of rose-like Pd-Fe3O4 nanocomposites via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(OAc)2, followed by the immobilization of Au nanoparticles (NPs) onto the Pd-Fe3O4 supports, is reported. The morphology of these hybrid nanostructures could be easily controlled by varying the amount of Fe(CO)5 and the reaction temperature. Moreover, the synthesized Au/Pd-Fe3O4 catalyst exhibited high catalytic activity for the tandem synthesis of 2-phenylindoles and demonstrated magnetic recyclability.A facile synthesis of rose-like Pd-Fe3O4 nanocomposites via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(OAc)2, followed by the immobilization of Au nanoparticles (NPs) onto the Pd-Fe3O4 supports, is reported. The morphology of these hybrid nanostructures could be easily controlled by varying the amount of Fe(CO)5 and the reaction temperature. Moreover, the synthesized Au/Pd-Fe3O4 catalyst exhibited high catalytic activity for the tandem synthesis of 2-phenylindoles and demonstrated magnetic recyclability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01441g

  20. Bio-based hyperbranched polyurethane/Fe3O4 nanocomposites: smart antibacterial biomaterials for biomedical devices and implants

    International Nuclear Information System (INIS)

    The fabrication of a smart magnetically controllable bio-based polymeric nanocomposite (NC) has immense potential in the biomedical domain. In this context, magneto-thermoresponsive sunflower oil modified hyperbranched polyurethane (HBPU)/Fe3O4 NCs with different wt.% of magnetic nanoparticles (Fe3O4) were prepared by an in situ polymerization technique. Fourier-transform infrared, x-ray diffraction, vibrating sample magnetometer, scanning electron microscope, transmission electron microscope, thermal analysis and differential scanning calorimetric were used to analyze various physico-chemical structural attributes of the prepared NC. The results showed good interfacial interactions between HBPU and well-dispersed superparamagnetic Fe3O4, with an average diameter of 7.65 nm. The incorporation of Fe3O4 in HBPU significantly improved the thermo-mechanical properties along with the shape-memory behavior, antibacterial activity, biocompatibility as well as biodegradability in comparison to the pristine system. The cytocompatibility of the degraded products of the NC was also verified by in vitro hemolytic activity and MTT assay. In addition, the in vivo biocompatibility and non-immunological behavior, as tested in Wistar rats after subcutaneous implantation, show promising signs for the NC to be used as antibacterial biomaterial for biomedical device and implant applications. (paper)device and implant applications. (paper)

  1. Synthesis of Core-Shell Magnetic Fe3O4@poly(m-Phenylenediamine) Particles for Chromium Reduction and Adsorption.

    Science.gov (United States)

    Wang, Ting; Zhang, Liyuan; Li, Chaofang; Yang, Weichun; Song, Tingting; Tang, Chongjian; Meng, Yun; Dai, Shuo; Wang, Haiying; Chai, Liyuan; Luo, Jian

    2015-05-01

    Magnetic Fe3O4@poly(m-phenylenediamine) particles (Fe3O4@PmPDs) with well-defined core-shell structure were first designed for high performance Cr(VI) removal by taking advantages of the easy separation property of magnetic nanoparticles (MNPs) and the satisfactory adsorption property of polymers. Through controlling the polymerization on MNPs, directly coating was realized without the complicated premodification procedures. The particle property and adsorption mechanism were analyzed in details. Fe3O4@PmPDs exhibited tunable PmPD shell thickness from 10 to 100 nm, high magnetic (?150 to ?73 emu g(-1)) and facile separation property by magnet. The coating of PmPD significantly enhanced Cr(VI) adsorption capacity from 46.79 (bare MNPs) to 246.09 mg g(-1) (71.55% PmPD loading proportion), much higher than many reported composite adsorbents. The high Cr(VI) removal performance was attributed to the adsorption of Cr(VI) on protonated imino groups and the efficient reduction of Cr(VI) to Cr(III) by amine, followed by Cr(III) chelated on imino groups, which are spontaneous and endothermic. The Fe3O4@PmPDs have great potential in treating Cr(VI)-contaminated water. PMID:25867789

  2. Label-free detection of aflatoxin M1 with electrochemical Fe3O4/polyaniline-based aptasensor

    International Nuclear Information System (INIS)

    The selective detection of ultratrace amounts of aflatoxin M1 (AFM1) is extremely important for food safety since it is the most toxic mycotoxin class that is allowed to be present on cow milk with strictly low regulatory levels. In this work, Fe3O4 incorporated polyaniline (Fe3O4/PANi) film has been polymerized on interdigitated electrode (IDE) as sensitive film for AFM1 electrochemical biosensor. The immobilized aptamers as an affinity capture reagent and magnetic nanoparticles for signal amplification element have been employed in the sensing platform. Label-free and direct detection of the aptamer-AFM1 on Fe3O4/PANi interface were performed via electrochemical signal change, acquired by cyclic and square wave voltammetries. With a simplified strategy, this electrochemical aptasensor shows a good sensitivity to AFM1 in the range of 6–60 ng·L?1, with the detection limit of 1.98 ng·L?1. The results open up the path for designing cost effective aptasensors for other biomedical applications. Highlights: ? Label-free detection of the aptamer-AFM1 on Fe3O4/PANi interface ? Electrochemical aptasensor with a good sensitivity to AFM1 in the range of 6–60 ng·L?1, with detection limit of 1.98 ng·L?1 ? Advantages over other analytical techniques in terms of label free format, sensitivity, stability and analysis time

  3. Multifunctional Au-Fe3O4@MOF core-shell nanocomposite catalysts with controllable reactivity and magnetic recyclability.

    Science.gov (United States)

    Ke, Fei; Wang, Luhuan; Zhu, Junfa

    2015-01-21

    The recovery and reuse of expensive catalysts are important in both heterogeneous and homogeneous catalysis due to economic and environmental reasons. This work reports a novel multifunctional magnetic core-shell gold catalyst which can be easily prepared and shows remarkable catalytic properties in the reduction of 4-nitrophenol. The novel Au-Fe3O4@metal-organic framework (MOF) catalyst consists of a superparamagnetic Au-Fe3O4 core and a porous MOF shell with controllable thickness. Small Au nanoparticles (NPs) of 3-5 nm are mainly sandwiched between the Fe3O4 core and the porous MOF shell. Catalytic studies show that the core-shell structured Au-Fe3O4@MOF catalyst has a much higher catalytic activity than other reported Au-based catalysts toward the reduction of 4-nitrophenol. Moreover, this catalyst can be easily recycled due to the presence of the superparamagnetic core. Therefore, compared to conventional catalysts used in the reduction of 4-nitrophenol, this porous MOF-based magnetic catalyst is green, cheap and promising for industrial applications. PMID:25486865

  4. Nano-scale Au supported on Fe3O4: characterization and application in the catalytic treatment of 2,4-dichlorophenol

    International Nuclear Information System (INIS)

    Catalytic hydrodechlorination (HDC) is an effective means of detoxifying chlorinated waste. Gold nanoparticles supported on Fe3O4 have been tested in the gas phase (1 atm, 423 K) HDC of 2,4-dichlorophenol. Two 1% w/w supported gold catalysts have been prepared by: (i) stepwise deposition of Au on ?-Fe2O3 with subsequent temperature-programmed reduction at 673 K (Au/Fe3O4-step); (ii) direct deposition of Au on Fe3O4 (Au/Fe3O4-dir). TEM analysis has established the presence of Au at the nano-scale with a greater mean diameter (7.6 nm) on Au/Fe3O4-dir relative to Au/Fe3O4-step (4.5 nm). We account for this difference in terms of stronger (electrostatic) precursor/support interactions in the latter that can be associated with the lower pH point of zero charge (with respect to the final deposition pH) for Fe2O3. Both catalysts promoted the preferential removal of the ortho-Cl substituent in 2,4-dichlorophenol, generating 4-chlorophenol and phenol as products of partial and total HDC, respectively, where Au/Fe3O4-step delivered a two-fold higher rate (2 × 10?4 molCl h?1 mAu?2) when compared with Au/Fe3O4-dir. This unprecedented selectivity response is attributed to activation of the ortho-C–Cl to activation of the ortho-C–Cl bond via interaction with electron-deficient Au nanoparticles. The results demonstrate the feasibility of a controlled recovery/recycling of chlorophenol waste using nano-structured Au catalysts.

  5. Ferroferric oxide/polystyrene (Fe3O4/PS superparamagnetic nanocomposite via facile in situ bulk radical polymerization

    Directory of Open Access Journals (Sweden)

    2010-03-01

    Full Text Available Organo-modified ferroferric oxide superparamagnetic nanoparticles, synthesized by the coprecipitation of superparamagnetic nanoparticles in presence of oleic acid (OA, were incorporated in polystyrene (PS by the facile in situ bulk radical polymerization by using 2,2-azobisisobutyronitrile (AIBN as initiator. The transmission electron microscopy (TEM analysis of the resultant uniform ferroferric oxide/polystyrene superparamagnetic nanocomposite (Fe3O4/PS showed that the superparamagnetic nanoparticles had been dispersed homogeneously in the polymer matrix due to the surface grafted polystyrene, confirmed by Fourier transform infrared (FT-IR spectroscopy and thermogravimetric analysis (TGA. The superparamagnetic property of the Fe3O4/PS nanocomposite was testified by the vibrating sample magnetometer (VSM analysis. The strategy developed is expected to be applied for the large-scale industrial manufacturing of the superparamagnetic polymer nanocomposite.

  6. Magnetic solid-phase extraction based on mesoporous silica-coated magnetic nanoparticles for analysis of oral antidiabetic drugs in human plasma

    International Nuclear Information System (INIS)

    In the present work, magnetic nanoparticles embedded into mesoporous silica were prepared in two steps: first, magnetite was synthesized by oxidation–precipitation method, and next, the magnetic nanoparticles were coated with mesoporous silica by using nonionic block copolymer surfactants as structure-directing agents. The mesoporous SiO2-coated Fe3O4 samples were functionalized using octadecyltrimethoxysilane as silanizing agent. The pure and functionalized silica nanoparticles were physicochemically and morphologically characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The resultant magnetic silica nanoparticles were applied as sorbents for magnetic solid-phase extraction (MSPE) of oral antidiabetic drugs in human plasma. Our results revealed that the magnetite nanoparticles were completely coated by well-ordered mesoporous silica with free pores and stable pore walls, and that the structural and magnetic properties of the Fe3O4 nanoparticles were preserved in the applied synthesis route. Indeed, the sorbent material was capable of extracting the antidiabetic drugs from human plasma, being useful for the sample preparation in biological matrices. - Highlights: • SBA-15/Fe3O4 was synthesized and functionalized with octadecyltrimethoxysilane. • Magnetite nanoparticles were completely coated by well-ordered mesoporous silica. • The samples were used as sorbent for magnetic solid-phase extraction (MSPE). • The sorbent material was capable of extracting drugs from human plasma. • The extraction ability makes the material a candidate to be employed as MSPE

  7. Electronic structure of charge-ordered Fe3O4

    CERN Document Server

    Leonov, I; Antonov, V N; Anisimov, V I

    2006-01-01

    The electronic structure of the low-temperature (LT) monoclinic magnetite, Fe3O4, is investigated using the local spin density approximation (LSDA) and the LSDA+U method. The self-consistent charge ordered LSDA+U solution has a pronounced [001] charge density wave character. In addition, a minor [00{1/2}] modulation in the phase of the charge order (CO) also occurs. While the existence of CO is evidenced by the large difference between the occupancies of the minority spin t_{2g} states of ``2+'' and ``3+'' Fe_B cations, the total 3d charge disproportion is small, in accord with the valence-bond-sum analysis of structural data. Weak Fe orbital moments of ~0.02 mB are obtained from relativistic calculations for the CO phase which is in good agreement with recent x-ray magnetic circular dichroism measurements. Optical, magneto-optical Kerr effect, and O K-edge x-ray absorption spectra calculated for the charge ordered LSDA+U solution are compared to corresponding LSDA spectra and to available experimental data. ...

  8. Synthesis of double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres and their catalytic applications

    Science.gov (United States)

    Li, Jie; Tan, Li; Wang, Ge; Yang, Mu

    2015-03-01

    Double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres were successfully synthesized through loading Au nanoparticles on the Fe3O4/TiO2 support by a in situ reduction of HAuCl4 with NaBH4 aqueous solution. These microspheres possess tunable cavity size, adjustable shell layers, high structural stability and large specific surface area. The Au nanoparticles of approximately 5 nm in diameter were loaded both on the TiO2 nanofibers and inside the cavities of sea urchin-like yolk-shell Fe3O4/TiO2 microspheres. The sea urchin-like structure composed of TiO2 nanofibers ensure the good distribution of the Au nanoparticles, while the novel double-shelled yolk-shell structure guarantees the high stability of the Au nanoparticles. Furthermore, the Fe3O4 magnetic core facilitates the convenient recovery of the catalyst by applying an external magnetic field. The Fe3O4/TiO2/Au microspheres display excellent activities and recycling properties in the catalytic reduction of 4-nitrophenol (4-NP): the rate constant is 1.84 min?1 and turnover frequency is 5457 h?1.

  9. Sulfhydryl-Modified Fe3O4@SiO2 Core/Shell Nanocomposite: Synthesis and Toxicity Assessment in Vitro.

    Science.gov (United States)

    Guo, Xueyi; Mao, Fangfang; Wang, Weijia; Yang, Ying; Bai, Zhiming

    2015-07-15

    The objectives of this study are to prepare sulfhydryl-modified Fe3O4@SiO2 core/shell magnetic nanocomposites, assess their toxicity in vitro, and explore their potential application in the biomedical fields. Fe3O4 nanoparticles synthesized by facile solvothermal method were coated with SiO2 via the Stöber method and further modified by the meso-2,3-dimercaptosuccinic acid (DMSA) to prepare Fe3O4@SiO2@DMSA nanoparticles. The morphology, structure, functional groups, surface charge, and magnetic susceptibility of the nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, zeta potential analysis, dynamic laser scattering, and vibrating sample magnetometer. Cytotoxicity tests and hemolysis assay were also carried out. Experimental results show that the toxicity of sulfhydryl-modified Fe3O4@SiO2 core/shell nanoparticles in mouse fibroblast (L-929) cell lines is between grade 0 and grade 1, and the material lacks hemolytic activity, indicating good biocompatibility of this Fe3O4@SiO2@DMSA nanocomposite, which is suitable for further application in biochemical fields. PMID:26083720

  10. Synthesis of double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres and their catalytic applications.

    Science.gov (United States)

    Li, Jie; Tan, Li; Wang, Ge; Yang, Mu

    2015-03-01

    Double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres were successfully synthesized through loading Au nanoparticles on the Fe3O4/TiO2 support by a in situ reduction of HAuCl4 with NaBH4 aqueous solution. These microspheres possess tunable cavity size, adjustable shell layers, high structural stability and large specific surface area. The Au nanoparticles of approximately 5 nm in diameter were loaded both on the TiO2 nanofibers and inside the cavities of sea urchin-like yolk-shell Fe3O4/TiO2 microspheres. The sea urchin-like structure composed of TiO2 nanofibers ensure the good distribution of the Au nanoparticles, while the novel double-shelled yolk-shell structure guarantees the high stability of the Au nanoparticles. Furthermore, the Fe3O4 magnetic core facilitates the convenient recovery of the catalyst by applying an external magnetic field. The Fe3O4/TiO2/Au microspheres display excellent activities and recycling properties in the catalytic reduction of 4-nitrophenol (4-NP): the rate constant is 1.84 min(-1) and turnover frequency is 5457 h(-1). PMID:25665732

  11. Superparamagnetic Fe3O4 particles formed by oxidation of pyrite heated in an anoxic atmosphere

    Science.gov (United States)

    Thorpe, A.N.; Senftle, F.E.; Talley, R.; Hetherington, S.; Dulong, F.

    1990-01-01

    As a follow-up to previous gas analysis experiments in which pyrite was heated to 681 K in an anoxic (oxygen starved) atmosphere, the first oxidation product, FeSO4, was studied as a bulk material. No decomposition of FeSO4 to Fe3O4 was observed in the temperature range studied. The lack of decomposition of bulk FeSO4 to Fe3O4 suggests that FeS2 oxidizes directly to Fe3O4, or that FeSO4, FeS2 and O2 react together to form Fe3O4. Magnetic susceptibility and magnetization measurements, along with magnetic hysteresis curves, show that small particles of Fe3O4 form on the pyrite surface, rather than a continuous layer of bulk Fe3O4. A working model describing the oxidation steps is presented. ?? 1990.

  12. SYNTHESIS, CHARACTERIZATION AND BIOLOGICAL EVALUATION OF A Fe3O4/C12 CORE/SHELL NANOSYSTEM

    OpenAIRE

    Alexandru Mihai Grumezescu; Ecaterina Andronescu; Anton Ficai; Dan Eduard Mihaiescu; Bogdan Stefan Vasile; Coralia Bleotu

    2012-01-01

    Lauric acid (C12) functionalized Fe3O4 nanoparticles were fabricated and characterized by XRD, FT-IR, DTA-TG and TEM. Lauric acid was used as a coating agent, controlling particle size and aggregation during the synthesis. XRD confirms the formation of magnetite. FT-IR evidenced the successful surface fictionalization with C12, peaks assigned to lauric acid being identified in the nanopowder. The obtained core/shell nanostructure consists of spherical particles of several nanometers long, acc...

  13. Cubic Silica-Coated and Amine-Functionalized FeCo Nanoparticles with High Saturation Magnetization

    Science.gov (United States)

    Kolhatkar, Arati G.; Nekrashevich, Ivan; Litvinov, Dmitri; Willson, Richard C.; Lee, T. Randall

    2015-01-01

    By systematically varying the reaction parameters in a liquid-phase reduction reaction, large FeCo nanocubes with tunable body diagonal lengths of 175, 350, and 450 nm were synthesized. The nanocubes were initially stabilized with poly(vinyl pyrrolidone) (PVP) and then coated with a relatively thin layer of silica (~55 nm thick), which allowed them to retain their cubic shape. The magnetization curves showed that the PVP-stabilized nanocubes exhibited a high saturation magnetization of 167 ± 4 emu/g. The saturation magnetization, however, decreased upon coating with silica to 146 ± 13 emu/g for the particles with 350 and 450 nm FeCo cores and 48 ± 1 emu/g for the particles with 175 nm FeCo cores. The silica-coated FeCo nanocubes were then functionalized with 3-(aminopropyl)-trimethoxysilane (APTMS), and a layer of surface-bound nanoparticle was generated by exposing the resultant amine-functionalized nanocubes to self-assembled monolayers (SAMs) on gold terminated with carboxylic-acid groups.

  14. Silica-coating as protective shell for the risk management of nanoparticles

    Science.gov (United States)

    Gardini, D.; Blosi, M.; Delpivo, C.; Ortelli, S.; Costa, A. L.

    2013-04-01

    Nanoparticles (NPs) surface functionalization with silica (SiO2) has attracted high attention due to hydrophilicity, biocompatibility, chemical and thermal stability of silica. The present work is addressed to the production and characterization of SiO2-coatings on titanium dioxide (TiO2) and silver (Ag) NPs dispersed in aqueous solutions (commercial nanosols) with the aim to manage the potential risk that such NPs could generate in occupational exposure scenarios. A colloidal approach, based on principles of heterocoagulation in which opposite charged NPs are forced to coagulate in hierarchical structures, imposed by their relative size and weight ratio, was followed. The results were compared with a chemical approach, based on nucleation of silica phase from silica precursor solutions on the surfaces of TiO2 or Ag NPs seeds. In order to increase the adhesion of silica on TiO2 and Ag surfaces, heterocoagulated sols were spray-dried and subsequently redispersed in water to check the feasibility of such approach at industrial level. Physicochemical properties such as zeta potential, electrical conductivity, particle-size distribution, specific surface area and morphology of the samples produced with different SiO2:TiO2 and SiO2:Ag weight ratios were collected and compared. Indirect evidences of silica coating were obtained.

  15. Biocompatibility of hydrophilic silica-coated CdTe quantum dots and magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Ruan Jing

    2011-01-01

    Full Text Available Abstract Fluorescent magnetic nanoparticles exhibit great application prospects in biomedical engineering. Herein, we reported the effects of hydrophilic silica-coated CdTe quantum dots and magnetic nanoparticles (FMNPs on human embryonic kidney 293 (HEK293 cells and mice with the aim of investigating their biocompatibility. FMNPs with 150 nm in diameter were prepared, and characterized by high-resolution transmission electron microscopy and photoluminescence (PL spectra and magnetometer. HEK293 cells were cultured with different doses of FMNPs (20, 50, and 100? g/ml for 1-4 days. Cell viability and adhesion ability were analyzed by CCK8 method and Western blotting. 30 mice were randomly divided into three groups, and were, respectively, injected via tail vein with 20, 60, and 100 ?g FMNPs, and then were, respectively, raised for 1, 7, and 30 days, then their lifespan, important organs, and blood biochemical parameters were analyzed. Results show that the prepared water-soluble FMNPs had high fluorescent and magnetic properties, less than 50 ?g/ml of FMNPs exhibited good biocompatibility to HEK293 cells, the cell viability, and adhesion ability were similar to the control HEK293 cells. FMNPs primarily accumulated in those organs such as lung, liver, and spleen. Lung exposed to FMNPs displayed a dose-dependent inflammatory response, blood biochemical parameters such as white blood cell count (WBC, alanine aminotransferase (ALT, and aspartate aminotransferase (AST, displayed significant increase when the FMNPs were injected into mice at dose of 100?g. In conclusion, FMNPs exhibit good biocompatibility to cells under the dose of less than 50 ?g/ml, and to mice under the dose of less than 2mg/kg body weight. The FMNPs' biocompatibility must be considered when FMNPs are used for in vivo diagnosis and therapy.

  16. HEAT TRANSFER ENHANCEMENT USING LOW VOLUME CONCENTRATIONS OF Fe3O4 NANOFLUID IN CIRCULAR PIPE

    Directory of Open Access Journals (Sweden)

    BHRAMARA PANITAPU

    2014-10-01

    Full Text Available Nanofluids are emerging as one of the effective means of enhancing the heat transfer compared to the conventional heat transfer fluids due enhancement of thermophysical properties of base fluids due to addition of nanosized particles. Numerical experiments were conducted for heat transfer inside a circular pipe subjected to constant heat flux with water as base fluid. Heat transfer enhancement was studied by adding low volume concentrations, viz., 0.1 to 0.6 % of Fe3O4 magnetic nanoparticles of particle size 36 nm in water. The numerical analysis of nanofluid was performed using the single phase approach for the Reynold Number of the flow ranging from 2500 – 22000. The results show that better enhancement was observed at higher Re and at higher volume fractions. The numerical results were compared with the experimental data available in the literature.

  17. Constructing magnetic polyaniline/metal hybrid nanostructures using polyaniline/Fe3O4 composite hollow spheres as supports

    International Nuclear Information System (INIS)

    Polyaniline (PANI)/Fe3O4 composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production. - Graphical abstract: TEM image of PANI/Fe3O4 hollow spheres which can be used as supports for a variety of catalysts such as noble metal nanoparticles. Based on the unique properties of polyaniline hollow spheres and Fe3O4 NPs, we designed the synthesis of polyaniline/Fe3O4 NPs composite hollow spheres as supports for catalysts suchlow spheres as supports for catalysts such as noble metal NPs. As a result, the obtained composites exhibit enhanced catalytic activities and can be easily separated from reaction mixture by using an NdFeB permanent magnet.

  18. Hydrothermal synthesis, magnetic and electromagnetic properties of hexagonal Fe3O4 microplates

    International Nuclear Information System (INIS)

    Magnetite (Fe3O4), with an inverse spinel structure, grows naturally in octahedral shape with eight equivalent {111} crystallographic planes. Here we demonstrated the successful morphology tuning of Fe3O4 microcrystal from the dominant octahedral shape to planar microplate shape by a facile hydrothermal method. The top and bottom surfaces of Fe3O4 microplates obtained under strongly alkaline and reductive conditions were bounded by {111} facets, and the formation of {111} twin planes was thought to be accountable for the anisotropic morphologies. The obtained Fe3O4 microplates delivered saturation magnetization (Ms) of 96.6 emu/g and coercivity (Hc) of 50 Oe. We also measured the electromagnetic properties of Fe3O4 microplates for possible applications as filler for electromagnetic wave absorption coatings. - Highlights: • Single-crystal Fe3O4 microplates with well-defined hexagonal shapes were successfully prepared. • Formation of twin planes was accountable for the anisotropic growth of Fe3O4 microplates. • Fe3O4 microplates showed potential applications as filler for EMA coatings

  19. Exchange bias effects in epitaxial Fe3O4/BiFeO3 heterostructures

    Science.gov (United States)

    Qu, T. L.; Zhao, Y. G.; Yu, P.; Zhao, H. C.; Zhang, S.; Yang, L. F.

    2012-06-01

    High quality Fe3O4 (5-20 nm)/BiFeO3 (BFO) heterostructures have been grown by pulsed laser deposition on (001) SrTiO3 (STO) substrates. Large exchange bias (EB) effects have been observed below 200 K in Fe3O4/BFO/STO structures compared with Fe3O4/STO structures. The exchange bias field decreases when increasing temperature or the thickness of Fe3O4 layer, and does not change after annealing in 0.1 T field from 700 K to room temperature across Neel temperature of BFO. A possible mechanism was proposed based on the interface spin coupling between Fe3O4 and BFO. Our work shed new light on the study of exchange bias effect in BFO system as well as the application for magnetoelectric devices.

  20. Nanostructured graphene/Fe3O4 incorporated polyaniline as a high performance shield against e