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Sample records for silica-coated fe3o4 nanoparticles

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

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

  2. Investigation of synthesized silica coating Fe3O4 nanoparticles efficiency in removal of NOM from water

    E. Karimi pasandideh

    2014-05-01

    Conclusion: Having high number of active surface sites, magnetic properties, easily separation using magnetic field, and its cost-effectiveness, the Fe3O4/SiO2 nanoparticles could be used as an efficient adsorbent in removal of humic acid from water.

  3. Investigation of synthesized silica coating Fe3O4 nanoparticles efficiency in removal of NOM from water

    E. Karimi pasandideh; R Rezaei Kalantary; S. Nasseri; A. H. Mahvi; R Nabizadeh; A Esrafili

    2014-01-01

    Background and Objective: The presence of natural organic materials (NOM) in water resources affects its quality (i.e. color, odor, and taste). In addition, it leads to the fouling of filters and membranes and reduces water treatment efficiency during flocculation/ coagulation. Moreover, NOM reacts with disinfectants and produces byproducts (DBPs), which are harmful to human health. Magnetic nanoparticles have been reported as effective adsorbents for the removal of pollutants from the aqueou...

  4. 磁性Fe3O4纳米颗粒%Fe3O4 Magnetic Nanoparticle

    赵朝辉; 姚素薇; 张卫国

    2005-01-01

      介绍了机械球磨法、水热法、微乳液法、超声沉淀法、水解法制备磁性纳米Fe3O4颗粒的工艺,归纳了各种制备方法的特点。针对当前纳米 Fe3O4颗粒的两大研究热点⎯⎯Fe3O4复合纳米颗粒和磁流体进行了综述,并展望了Fe3O4纳米颗粒的研究前景。%  Various preparation methods of Fe3O4 nanoparticle, such as mechanical milling, hydrothermal method, micro-emulsion method, sonochemical synthesis and hydrolytic method, are introduced, and the characteristics of these methods are summarized. Brief introduction is also given to the Fe3O4 composite material and magneto-fluid, which are two recent focusing fields on Fe3O4 nanoparticle research. Furthermore, research prospect of Fe3O4 nanoparticle is presented.

  5. Synthesis of Fe3O4@SiO2@polymer nanoparticles for controlled drug release

    2010-01-01

    Novel multifunctional nanoparticles containing a magnetic Fe3O4@SiO2 sphere and a biocompatible block copolymer poly(ethylene glycol)-b-poly(aspartate)(PEG-b-PAsp) were prepared.The silica coated on the superparamagnetic core was able to achieve a magnetic dispersivity,as well as to protect Fe3O4 against oxidation and acid corrosion.The PAsp block was grafted to the surface of Fe3O4@SiO2 nanoparticles by amido bonds,and the PEG block formed the outermost shell.The anticancer agent doxorubicin(DOX) was loaded into the hybrid nanoparticles via an electrostatic interaction between DOX and PAsp.The release rate of DOX could be adjusted by the pH value.

  6. Surface Modfication of Fe3O4 Nanoparticles

    LIU Yong-jian; JIA Hong-yi; ZHUANG Hong

    2006-01-01

    Nanometer particles are important portion of magnetic fluid. Fe3O4 magnetic nanoparticles were studied in this paper and the surface modification of Fe3O4 nanoparticles was investigated by a series of experiments. Fe3O4 magnetic nanoparticles were synthesized with pH value, temperature, and the dosage of surfactant. The phase, structure, size and magnetism of nanoparticles were tested by X-ray diffration (XRD), transmission electron microscopy (TEM) and magnetic balance. On the basis of the surface modification coating mechanism, the experimental phenomena and the effects on the variation of size, magnetism and stability of Fe3O4 nanoparticles were theoretically analyzed. X-Ray diffraction spectrum and TEM photograph show that 1) the nanoparticles structure is perfect, 2) the diameter of namoparticles is small and have good deliquescence, and 3) Sodium oleate is the anion surfactant. Therefore 1) the good condition of surface modification is in an acidic solution, 2) the best temperature of surface modification is at 80 ℃, and 3) the dosage of surfactant should be about 0.6 times of that of Fe2+.

  7. Graphene grafted silica-coated Fe3O4 nanocomposite as absorbent for enrichment of carbamates from cucumbers and pears prior to HPLC.

    Sun, Meng; Ma, Xiaoxing; Wang, Juntao; Wang, Weina; Wu, Qiuhua; Wang, Chun; Wang, Zhi

    2013-04-01

    In this paper, a novel graphene (G) grafted silica-coated Fe3O4 nanocomposite was fabricated by the chemical bonding of G onto the surface of silica-coated Fe3 O4 nanoparticles. Some carbamates (metolcarb, carbaryl, pirimicarb, and diethofencarb) in cucumber and pear samples were enriched by this nanocomposite prior to their determination by HPLC with UV detection. Experimental parameters that may affect the extraction efficiency were investigated. Under the optimum conditions, a linear response was achieved in the concentration range of 0.5-100.0 ng/g for metolcarb, carbaryl, and diethofencarb, and 1.0-100 ng/g for pirimicarb with the correlation coefficients (r) ranging from 0.9956 to 0.9984. The LOD (S/N = 3) of the method were found to be in the range from 0.08 to 0.2 ng/g. The RSDs were in the range from 2.4 to 5.8%. The results indicated that the G grafted silica-coated Fe3 O4 nanocomposite was stable and efficient for magnetic SPE and has a great application potential for the preconcentration of other organic pollutants from real samples. PMID:23404952

  8. Solvothermal synthesis of magnetic Fe3O4 microparticles via self-assembly of Fe3O4 nanoparticles

    Wei Zhang; Fenglei Shen; Ruoyu Hong

    2011-01-01

    Ferromagnetic Fe3O4 nanoparticles were synthesized and then self-assembled into microparticles via a solvothermal method, using FeCI3.6H2O as the iron source, sodium oleate as the surfactant, and ethylene glycol as the reducing agent and solvent. The obtained Fe3O4 microparticles were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and vibrating sample magnetometer (VSM). The size and morphology of the particles were examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Fe3O4 microparticles of nearly monodisperse diameters, controllable in the range of 120-400 nm, consist of assemblies of Fe3O4nanoparticles with a diameter of 22 nm. The effects of reaction time, amount of surfactant and NaAc on the products were discussed. Interestingly, by using the pre-synthesized Fe3O4 microparticles as the growth substrates, spherical and smooth-looking Fe3O4 microparticles with average diameter of lμmwere obtained. A plausible formation process was discussed.

  9. Facile synthesis of superparamagnetic Fe3O4@Au nanoparticles for photothermal destruction of cancer cells.

    Ren, Jinfeng; Shen, Shun; Pang, Zhiqing; Lu, Xiaohui; Deng, Chunhui; Jiang, Xinguo

    2011-11-14

    Superparamagnetic Fe(3)O(4) nanoparticles with positive surface ξ-potential were synthesized via a solvothermal route. After Fe(3)O(4) was mixed with HAuCl(4) and NaBH(4), the reduced Au nanoparticles could be directly adsorbed onto the surface of Fe(3)O(4) nanoparticles. The as-synthesized nanocomposites were successfully applied to photothermal destruction of cancer cells. PMID:21952492

  10. Polyethyleneimine-modified superparamagnetic Fe3O4 nanoparticles for lipase immobilization: Characterization and application

    Magnetically separable nanospheres consisting of polyethyleneimine (PEI) and succinated PEI grafted on silica coated magnetite (Fe3O4) were prepared and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, vibrating sample magnetometer, scanning electron microscopy and transmission electron microscopy. The prepared magnetic nanoparticles were then applied for physical adsorption or covalent attachment of Thermomyces lanuginosa lipase (TLL) via glutaraldehyde or hexamethylene diisocyanate. The reusability, storage, pH and thermal stabilities of the immobilized enzymes compared to that of free lipase were examined. The obtained results showed that the immobilized lipase on MNPs@PEI-GLU was the best biocatalyst which retained 80% of its initial activity after 12 cycles of application. The immobilized lipase on the selected support (MNPs@PEI-GLU) was also applied for the synthesis of ethyl valerate. Following 24 h incubation of the immobilized lipase on the selected support in n-hexane and solvent free media, the esterification percentages were 72.9% and 28.9%, respectively. - Graphical abstract: A schematic of the preparation of PEI- and succinated PEI-grafted Fe3O4 MNPs (MNPs@PEI) and the immobilization of lipase by covalent bonding and adsorption. - Highlights: • Functionalized polyethylenimine-grafted magnetic nanoparticles were synthesized. • The prepared supports were fully characterized by various analysis methods. • Lipase was immobilized on the nanostructures by adsorption and covalent attachment. • Immobilized lipase produced ethyl valerate in solvent free medium

  11. CHARACTERIZATION OF MANGANESE PHTHALOCYANINE-Fe3O4 NANOPARTICLE COMPOSITE AND ITS ELECTROMAGNETORHEOLOGICAL FLUID

    1999-01-01

    Manganese phthalocyanine (MnPc)-Fe3O4 nanoparticles composite was prepared and characterized. The results show that MnPc are complexed on the surface of Fe3O4 nanoparticles in the state of single molecule. There is effective composite between MnPc and Fe3O4 nanoparticles which can improve the antioxidization ability of Fe3O4 nanoparticles greatly. The composite was dispersed into chlorinated paraffin oil to form electromagnetorheological (EMR) fluid with high activity,and the EMR properties of this EMR fluid are studied.

  12. Magnetite Fe3O4 nanoparticles synthesis by wet chemical reduction and their characterization

    Chaki, S. H.; Malek, Tasmira J.; Chaudhary, M. D.; Tailor, J. P.; Deshpande, M. P.

    2015-09-01

    The authors report the synthesis of Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its characterization. Ferric chloride hexa-hydrate (FeCl3 · 6H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the synthesized Fe3O4 nanoparticles was determined by energy dispersive analysis of x-rays technique. The x-ray diffraction (XRD) technique was used for structural characterization of the nanoparticles. The crystallite size of the nanoparticles was determined using XRD data employing Scherrer’s formula and Hall-Williamson’s plot. Surface morphology of as-synthesized Fe3O4 nanoparticles was studied by scanning electron microscopy. High resolution transmission electron microscopy analysis of the as-synthesized Fe3O4 nanoparticles showed narrow range of particles size distribution. The optical absorption of the synthesized Fe3O4 nanoparticles was studied by UV-vis-NIR spectroscopy. The as-synthesized nanoparticles were analyzed by Fourier transform infrared spectroscopy technique for absorption band study in the infrared region. The magnetic properties of the as-synthesized Fe3O4 nanoparticles were evaluated by vibrating sample magnetometer technique. The thermal stability of the as-synthesized Fe3O4 nanoparticles was studied by thermogravimetric technique. The obtained results are elaborated and discussed in details in this paper.

  13. Synthesis, characterization and magnetorheological study of 3-aminopropyltriethoxysilane-modified Fe3O4 nanoparticles

    Wang, Guangshuo; Ma, Yingying; Tong, Yu; Dong, Xufeng

    2016-03-01

    In this study, monodisperse Fe3O4 nanoparticles were synthesized successfully using a sonochemical method in the presence of 3-aminopropyltriethoxysilane (APTES). The morphology, microstructure and magnetic properties of the bare Fe3O4 and APTES-coated Fe3O4 were investigated in detail by TEM, XRD, FTIR and SQUID. It was found that APTES-coated Fe3O4 showed relatively good dispersion with a narrow size distribution of 8.4 ± 2.1 nm diameter. The functionalization of Fe3O4 was proved to be covalent linking between Fe3O4 and APTES. The field-dependent magnetization curve indicated superparamagnetic behavior of Fe3O4-APTES with a saturation magnetization (M s) of 70.5 emu g-1 at room temperature. A magnetorheological (MR) fluid was prepared using the obtained Fe3O4-APTES nanoparticles with 25 wt% particles, and its MR properties were tested using a Physica MCR301 rheometer fitted with an MRmodule. The results showed that the as-prepared APTES-coated Fe3O4 nanoparticle-based MR fluid exhibited typical MR effects, with increasing viscosity, shear stress and yield stress depending on the applied magnetic field strength.

  14. Study on the Properties of Metallophthalocyanine-Fe3O4 Nanoparticles Composite

    2001-01-01

    The solubility,antioxidation ability,thermal stability,coercivity Hc and long term stability of MPc-Fe3O4-nanoparticles composite(M=Co,Cu,Ni,Mn) have been studied.The results show that MPc-Fe3O4 nanoparticles composite can be easily dissolved in dilute acid.The dissolving rate of different MPc-Fe3O4 nanoparticles composite is in the following order:M=Mn~M=Co<M=Cu<M=Ni.The antioxidation ability of Fe3O4 nanoparticles are improved greatly after their complex with MPc and there is good relationship between Toxidation of Fe3O4 nanoparticles and n ,the complex layers of MPc on the surface of the composite.The results also show that the thermal stability of Fe3O4 nanoparticles increases greatly and the Hc of them decreases dramatically after Fe3O4 nanoparticles form nanoscale composite with MPc.MPc-Fe3O4 nanoparticles composite have high long term stability.

  15. Green fabrication of agar-conjugated Fe3O4 magnetic nanoparticles

    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

    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 magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid

    Qin, H.; Wang, C. M.; Dong, Q. Q.; Zhang, L.; Zhang, X.; Ma, Z. Y.; Han, Q. R.

    2015-05-01

    A novel and simple method has been proposed to prepare magnetic Fe3O4-chitosan nanoparticles loaded with isoniazid (Fe3O4/CS/INH nanocomposites). Efforts have been made to develop isoniazid (INH) loaded chitosan (CS) nanoparticles by ionic gelation of chitosan with tripolyphosphate (TPP). The factors that influence the preparation of chitosan nanoparticles, including the TPP concentration, the chitosan/TPP weight ratio and the chitosan concentration on loading capacity and encapsulation efficiency of chitosan nanoparticles were studied. The magnetic Fe3O4 nanoparticles were prepared by co-precipitation method of Fe2+ and Fe3+. Then the magnetic Fe3O4/CS/INH nanocomposites were prepared by ionic gelation method. The magnetic Fe3O4 nanoparticles and magnetic Fe3O4/CS/INH nanocomposites were characterized by XRD, TEM, FTIR and SQUID magnetometry. The in vitro release of Fe3O4/CS/INH nanocomposites showed an initial burst release in the first 10 h, followed by a more gradual and sustained release for 48 h. It is suggested that the magnetic Fe3O4/CS/INH nanocomposites may be exploited as potential drug carriers for controlled-release applications in magnetic targeted drugs delivery system.

  18. Preparation and characterization of magnetic Fe3O4–chitosan nanoparticles loaded with isoniazid

    A novel and simple method has been proposed to prepare magnetic Fe3O4–chitosan nanoparticles loaded with isoniazid (Fe3O4/CS/INH nanocomposites). Efforts have been made to develop isoniazid (INH) loaded chitosan (CS) nanoparticles by ionic gelation of chitosan with tripolyphosphate (TPP). The factors that influence the preparation of chitosan nanoparticles, including the TPP concentration, the chitosan/TPP weight ratio and the chitosan concentration on loading capacity and encapsulation efficiency of chitosan nanoparticles were studied. The magnetic Fe3O4 nanoparticles were prepared by co-precipitation method of Fe2+ and Fe3+. Then the magnetic Fe3O4/CS/INH nanocomposites were prepared by ionic gelation method. The magnetic Fe3O4 nanoparticles and magnetic Fe3O4/CS/INH nanocomposites were characterized by XRD, TEM, FTIR and SQUID magnetometry. The in vitro release of Fe3O4/CS/INH nanocomposites showed an initial burst release in the first 10 h, followed by a more gradual and sustained release for 48 h. It is suggested that the magnetic Fe3O4/CS/INH nanocomposites may be exploited as potential drug carriers for controlled-release applications in magnetic targeted drugs delivery system. - Highlights: • A novel and simple method for preparation of nanocomposites for biomedicine. • All the materials are non-toxic and biocompatibility. • This paper gives systematic study of the nanocomposites in biomedicine

  19. Biomimetic Mussel Adhesive Inspired Clickable Anchors Applied to the Functionalization of Fe3O4 Nanoparticles

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

    2010-01-01

    The functionalization of magnetite (Fe3O4) nanoparticles with dopamine-derived clickable biomimetic anchors is reported. Herein, an alkyne-modified catechol-derivative is employed as the anchor, as i) the catechol-functional anchor groups possess irreversible covalent binding affinity to Fe3O4 nanop

  20. Hydrothermal synthesis of superparamagnetic Fe3O4 nanoparticles with ionic liquids as stabilizer

    Highlights: • Superparamagnetic Fe3O4 nanoparticles with good dispersity have been synthesized via hydrothermal method. • Ionic liquid [C16mim]Cl acts as stabilizer for the Fe3O4 nanoparticles. • Fe3O4 nanoparticles have a saturation magnetization of 67.69 emu/g at 300 K. - Abstract: Superparamagnetic Fe3O4 nanoparticles have been successfully synthesized under hydrothermal condition with the assistant of ionic liquid 1-hexadecyl-3-methylimidazolium chloride ([C16mim]Cl). The structure and morphology of the sample have been investigated by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM), and the results indicate that the as-synthesized inverse spinel Fe3O4 nanoparticles have an average diameter of about 10 nm and exhibit relatively good dispersity. More importantly, it is found that [C16mim]Cl acts as stabilizer for the Fe3O4 nanoparticles by adsorbing on the particles surfaces to prevent the agglomeration. In addition, the obtained superparamagnetic Fe3O4 nanoparticles have a saturation magnetization of 67.69 emu/g at 300 K

  1. Radiation preparation and properties of Fe3O4-chitosan magnetic nanoparticles

    Fe3O4 nanoparticles were dispersed in paraffin and mixed with chitosan by various ratios into homogenous solutions, then gamma irradiated at dose of 40 kGy for preparation of Fe3O4-chitosan nanoparticles. The resulting Fe3O4-chitosan materials were characterized by transmission electron microscopy (TEM), vibrating sample magnetization (VMS) and X-ray diffraction (XRD). Average diameter of obtained nanoparticles increased, whereas its saturated magnetization reduced with chitosan ratio in the solution. The Fe3O4-chitosan nanoparticles obtained from the 5:1 Fe3O4/chitosan admixture were used as absorbents for removal of lead ions (Pb(II)) in aqueous solutions. The results revealed that adsorption capacity depended on the initial amount of Fe3O4-chitosan nanoparticles, and their maximum adsorption capacity for Pb(CH3COO)2.3H2O was 41.4 mg/g at ambient conditions. These results suggested that Fe3O4-chitosan nanoparticles can be applied as a promising adsorbent for removal of heavy metals from contaminated solutions in practice. (author)

  2. Preparation and enhanced properties of Fe3O4 nanoparticles reinforced polyimide nanocomposites

    Ding, Daowei; Yan, Xingru; Zhang, Xi; He, Qingliang; Qiu, Bin; Jiang, Dawei; Wei, Huige; Guo, Jiang; Umar, Ahmad; Sun, Luyi; Wang, Qiang; Khan, Mojammel A.; Young, David P.; Zhang, Xin; Weeks, Brandon; Ho, Thomas C.; Guo, Zhanhu; Wei, Suying

    2015-09-01

    Polyimide (PI) nanocomposite reinforced with Fe3O4 nanoparticles (NPs) at various NPs loadings levels of 5.0, 10.0, 15.0, and 20.0 wt% were prepared. The chemical interactions of the Fe3O4 NPs/PI nanocomposites were characterized using Fourier Transform Infrared (FT-IR) spectroscopy. X-ray Diffraction (XRD) results revealed that the addition of NPs had a significant effect on the crystallization of PI. Scanning electron microscope (SEM) and the atomic force microscope (AFM) were used to characterize the dispersion and surface morphology of the Fe3O4 NPs and the PI nanocomposites. The obtained optical band gap of the nanocomposites characterized using Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS) was decreased with increasing the Fe3O4 loading. Differential scanning calorimetry (DSC) results showed a continuous increase of Tg with increasing the Fe3O4 NPs loading. Some differences were observed in the onset decomposition temperature between the pure PI and nanocomposites since the NPs and the PI matrix were physically entangled together to form the nanocomposites. The contact angle of pure PI was larger than that of Fe3O4/PI nanocomposites films, and increased with increasing the loading of Fe3O4. The degree of swelling was increased with increasing the Fe3O4 loading and the swelling time. The dielectric properties of the nanocomposite were strongly related to the Fe3O4 loading levels. The Fe3O4/PI magnetic property also had been improved with increasing the loading of the magnetic nanoparticles.

  3. Characteristics of magnetic Fe3O4 nanoparticles encapsulated with human serum albumin

    2006-01-01

    Magnetic nanoparticles (Fe3O4) were prepared by chemical precipitation method using Fe2+ and Fe3+salts with sodium hydroxide in the nitrogen atmosphere. Fe3O4 nanoparticles were coated with human serum albumin(HSA) for magnetic resonance imaging as contrast agent. Characteristics of magnetic particles coated or uncoated were carried out using scanning electron microscopy and X-ray diffraction. Zeta potentials, package effects and distributions of colloid particles were measured to confirm the attachment of HSA on magnetic particles. Effects of Fe3O4 nanoparticles coated with HSA on magnetic resonance imaging were investigated with rats. The experimental results show that the adsorption of HSA on magnetic particles is very favorable to dispersing of magnetic Fe3O4 particles, while the sizes of Fe3O4 particles coated are related to the molar ratio of Fe3O4 to HSA. The diameters of the majority of particles coated are less than 100 nm. Fe3O4 nanoparticle coated with HSA has a good biocompatibility and low toxicity. This new contrast agent has some effects on the nuclear magnetic resonance imaging of liver and the lowest dosage is 20 μmol/kg for the demands of diagnosis.

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

    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. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe3O4@Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe3O4@Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe3O4@Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

  5. PREPARATION,COMPLEX MECHANISM AND STRUCTURE MODEL OF METALLOPHTHALOC- YANINE-Fe3O4 NANOPARTICLES COMPOSITE

    2000-01-01

    MPc-Fe3O4-nanoparticles composite(M=Co, Cu, Ni, Mn) have been prepared and the factors that influence their mean size have been studied. The mean size of the nanoparticles composite increase with the increase of complex temperature. The interaction of MPc with Fe3O4 nanoparticles has been studied. There are M-O covalent bonding and ionic bonding between MPc and Fe3O4 nanoparticles. The intensities of M-O bonding and ionic bonding are in vestigated .The complex mechanism of MPc with Fe3O4 nanoparticles have been studied. First, there are complex between MPc and all Fe3O4 nanoparticles. Then, Fe3O4 nanoparticles accumulate together to form the accumulators, MPc have the function of cohering Fe3O4 nanoparticles. A considerable number of MPc combine with Fe3O4 nanoparticles on the surface of the accumulators to form MPc-Fe3O4 nanoparticles composite. All the above proesses take place spontaneously. The structure model of MPc-Fe3O4 nanoparticles composite has also been investigated. Inside the MPc-Fe3O4 nanoparticles composite, Fe3O4 nanoparticles accumulate together without order, on the surface of the composite, MPc form molecular dispersion layer. The threshold of molecular dispersion layer are also investigated.

  6. Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

    K C Barick; D Bahadur

    2006-11-01

    The assembly of superparamagnetic Fe3O4 nanoparticles on submicroscopic SiO2 spheres have been prepared by an in situ reaction using different molar ratios of Fe3+/Fe2+ (50–200%). It has been observed that morphology of the assembly and properties of these hybrid materials composed of SiO2 as core and Fe3O4 nanoparticles as shell depend on the molar ratio of Fe3+/Fe2+.

  7. Inductive heat property of Fe3O4 nanoparticles in AC magnetic field for local hyperthermia

    ZHAO Donglin; ZENG Xianwei; XIA Qisheng; TANG Jintian

    2006-01-01

    Magnetite (Fe3O4) nanoparticles with different magnetic properties were prepared by coprecipitation of Fe3+ and Fe2+ with aqueous NaOH solution.The inductive heat properties of Fe3O4 nanoparticles in an alternating current (AC) magnetic field were investigated for local hyperthermia. The maximum saunder the optimum conditions of Fe3+:Fe2+ molar ratio at 1.8:1. The Ms of Fe3O4 nanoparticles decreased as the Fe3+ /Fe2+ molar ratio increased. But the coercivity Hc increases with the increasing of Fe3+ /Fe2+ molar ratio. Exposed in the AC magnetic field for 29 min, the temperatures of physiological saline suspension containing Fe3O4 nanoparticles were 42-97.5 ℃.The inductive heat property of Fe3O4 nanoparticles in AC magnetic field decreases as Hc increases, but increases with the increasing of Ms. The Fe3O4 nanoparticles would be useful as good thermoseeds for localized hyperthermia treatment of cancers.

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

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

    2014-09-01

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

  9. Magnetic field synthesis of Fe 3O 4 nanoparticles used as a precursor of ferrofluids

    Hong, R. Y.; Pan, T. T.; Han, Y. P.; Li, H. Z.; Ding, J.; Han, Sijin

    2007-03-01

    Methods to synthesize magnetic Fe 3O 4 nanoparticles and to modify the nanoparticle surface are presented in this paper. In these methods, Fe 3O 4 nanoparticles were prepared by co-precipitation, and the aging of nanoparticles was improved by applied magnetic field. The obtained nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Thereafter, to enhance the compatibility between nanoparticles and water, an effective surface modification method was developed by grafting acrylic acid onto the nanoparticle surface. FT-IR, XRD, transmission electron microscopy (TEM), and thermogravimetry (TG) were used to characterize the resultant sample. The testing results indicated that the polyacrylic acid chains have been covalently bonded to the surface of magnetic Fe 3O 4 nanoparticles. The effects of initiator dosage, monomer concentration, and reaction temperature on the characteristics of surface-modified Fe 3O 4 nanoparticles were investigated. Moreover, the Fe 3O 4-g-PAA hybrid nanoparticles were dispersed in water to form ferrofluids (FFs). The obtained FFs were characterized by UV-vis spectrophotometer, Gouy magnetic balance and laser particle-size analyzer. The testing results showed that the high-concentration FF had excellent stability, with high susceptibility and high saturation magnetization. The rheological properties of the FFs were also investigated using a rotating rheometer.

  10. Effect of silica capping on the oxidation of Fe3O4 nanoparticles in dispersion revealed by x-ray absorption spectroscopy

    Warland, A.; Antoniak, C.; Darbandi, M.; Weis, C.; Landers, J.; Keune, W.; Wende, H.

    2012-06-01

    Fe3O4 nanoparticles have been investigated as they are biocompatible and their surface can be functionalized. We synthesized iron oxide nanoparticles using a water-in-oil microemulsion method. Bare and silica-coated iron oxide nanoparticles of a core size of 6 nm dispersed in ethanol have been investigated by means of x-ray absorption spectroscopy (XAS). Due to a dedicated experimental setup the particles can be measured directly in dispersion. XAS allows us to disentangle the contributions of the Fe2+ and Fe3+ ions and therefore to estimate the amount of Fe3O4 in the particles. In case of the silica coated particles a high amount of magnetite was obtained. In contrast, the bare nanoparticles showed indications of a further oxidation into γ-Fe2O3 even in dispersion.

  11. Fe3O4/Au composite nano-particles and their optical properties

    CUI; Yali; HUI; Wenli; SU; Jing; WANG; Yani; CHEN; Chao

    2005-01-01

    Fe3O4/Au composite particles with core/shell structure were prepared by reduction of Au3+ with hydroxylamine in the presence of an excess of Fe3O4 as seeds.The resultant colloids, with an average diameter of less than 100 nm, were obtained; the remaining non-reacted Fe3O4 seeds can be removed by treatment with diluted HCl solution.The Fe3O4/Au colloids exhibit a characteristic peak of UV-visible spectra, which largely depend on the size of the particle and the suspension medium.The localized surface plasmon resonance peaks red shift and broaden with increased nanoparticle diameter or increased solvent ionic strength.The optical property is very important in the establishment of means for the detection of biomolecules.

  12. TEA controllable preparation of magnetite nanoparticles (Fe3O4 NPs) with excellent magnetic properties

    Han, Chengliang; Zhu, Dejie; Wu, Hanzhao; Li, Yao; Cheng, Lu; Hu, Kunhong

    2016-06-01

    A fast and controllable synthesis method for superparamagnetic magnetite nanoparticles (Fe3O4 NPs) was developed in Fe(III)-triethanolamine (TEA) solution. The phase structure, morphology and particle size of the as-synthesized samples were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that the magnetic particles were pure Fe3O4 with mean sizes of approximately 10 nm. The used TEA has key effects on the formation of well dispersing Fe3O4 NPs. Vibrating sample magnetometer (VSM) result indicated that the as-obtained Fe3O4 NPs exhibited superparamagnetic behavior and the saturation magnetization (Ms) was about 70 emu/g, which had potential applications in magnetic science and technology.

  13. Green Synthesis of Magnetite (Fe3O4) Nanoparticles Using Seaweed (Kappaphycus alvarezii) Extract.

    Yew, Yen Pin; Shameli, Kamyar; Miyake, Mikio; Kuwano, Noriyuki; Bt Ahmad Khairudin, Nurul Bahiyah; Bt Mohamad, Shaza Eva; Lee, Kar Xin

    2016-12-01

    In this study, a simple, rapid, and eco-friendly green method was introduced to synthesize magnetite nanoparticles (Fe3O4-NPs) successfully. Seaweed Kappaphycus alvarezii (K. alvarezii) was employed as a green reducing and stabilizing agents. The synthesized Fe3O4-NPs were characterized with X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) techniques. The X-ray diffraction planes at (220), (311), (400), (422), (511), (440), and (533) were corresponding to the standard Fe3O4 patterns, which showed the high purity and crystallinity of Fe3O4-NPs had been synthesized. Based on FT-IR analysis, two characteristic absorption peaks were observed at 556 and 423 cm(-1), which proved the existence of Fe3O4 in the prepared nanoparticles. TEM image displayed the synthesized Fe3O4-NPs were mostly in spherical shape with an average size of 14.7 nm. PMID:27251326

  14. Controllable synthesis and characterization of Fe3O4/Au composite nanoparticles

    Fe3O4/Au composite nanoparticles (GoldMag NPs) have received considerable attention because of their advantageous properties arisen from both individual Au and Fe3O4 nanoparticles. Many efforts have been devoted to the synthesis of these composite nanoparticles. Herein, GoldMag NPs were reported to be synthesized by two-step method. Fe3O4 nanoparticles were prepared by co-precipitation and modified by the citric acid, and then citric acid-coated Fe3O4 nanoparticles were used as seeds in sodium citrate solution to reduce the HAuCl4. The size of obtained nanoparticles was geared from 25 to 300 nm by controlling the concentration of reactants. The GoldMag NPs were characterized by UV–vis spectrometer, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The GoldMag NPs showed good superparamagnetism at room temperature and were well dispersed in water with surface plasmon resonance absorption peak varied from 538 nm to 570 nm. - Highlights: • A low cost, simple manipulation and nontoxic approach was designed for preparation of magnetic Fe3O4/Au (GoldMag NPs) nanocomposites. • The size of GoldMag NPs could be controlled from 25 to 300 nm by varying the concentration of reactants. • GoldMag NPs possessed good magnetic response, high dispersion, and good stability

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

    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. Controlled Synthesis and Characterization of Monodisperse Fe3O4 Nanoparticles

    SHI,Rongrong; GAO,Guanhua; YI,Ran; ZHOU,Kechao; QIU,Guanzhou; LIU,Xiaohe

    2009-01-01

    Monodisperse Fe3O4 nanoparticles were successfully synthesized through the thermal decomposition of iron acetylacetonate in octadecene solvent in the presence of oleic acid and oleylamine.The influences of experimental parameters,such as reacting temperature,amounts and kinds of surfactants,solvents,oleic acid and oleylamine,on the size and shape of monodisperse Fe3O4 nanoparticles were discussed.The phase structures,morphology,and size of the as-prepared products were investigated in detail by X-ray diffraction (XRD),transmission electron microscopy (TEM),selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM).Magnetic property was measured using a vibrating sample magnetometer (VSM) at room temperature,which revealed that Fe3O4 nanoparticles were of ferromagnetism with a saturation magnetization (Ms) of 74.0 emu/g and coercivity (Hc) of 72.6 Oe.

  17. Inductive heat property of Fe3O4/polymer composite nanoparticles in an ac magnetic field for localized hyperthermia.

    Zhao, Dong-Lin; Zhang, Hai-Long; Zeng, Xian-Wei; Xia, Qi-Sheng; Tang, Jin-Tian

    2006-12-01

    The magnetite (Fe(3)O(4)) nanoparticles were prepared by coprecipitation of Fe(3+) and Fe(2+) with an aqueous NaOH solution. The Fe(3)O(4)/polyaniline (PANI) magnetic composite nanoparticles with a core-shell structure with a diameter of 30-50 nm were prepared via an in situ polymerization of aniline in an aqueous solution containing the Fe(3)O(4) magnetic fluid. The inductive heat property of Fe(3)O(4)/PANI composite nanoparticles in an alternating current (ac) magnetic field was investigated. The potential of Fe(3)O(4)/PANI nanoparticles was evaluated for localized hyperthermia treatment of cancers. The saturation magnetization, M(s), and coercivity, H(c), are 50.05 emu g(-1) and 137 Oe for Fe(3)O(4) nanoparticles and 26.34 emu g(-1) and 0 Oe for Fe(3)O(4)/PANI composite nanoparticles, respectively. Exposed in the ac magnetic field for 29 min, the temperatures of physiological saline suspensions containing Fe(3)O(4) nanoparticles or Fe(3)O(4)/PANI composite nanoparticles are 63.6 degrees C and 52.4 degrees C, respectively. The Fe(3)O(4)/PANI composite nanoparticles would be useful as good thermoseeds for localized hyperthermia treatment of cancers. PMID:18458406

  18. Protein surface labeling reactivity of N-hydroxysuccinimide esters conjugated to Fe3O4@SiO2 magnetic nanoparticles

    The N-hydroxysuccinimide (NHS) ester moiety is one of the most widely used amine reactive groups for covalent conjugation of proteins/peptides to other functional targets. In this study, a cleave-analyze approach was developed to quantify NHS ester groups conjugated to silica-coated iron oxide magnetic nanoparticles (Fe3O4@SiO2 MNPs). The fluorophore dansylcadaverine was attached to Fe3O4@SiO2 magnetic nanoparticles (MNPs) via reaction with NHS ester groups, and then released from the MNPs by cleavage of the disulfide bond in the linker between the fluorophore and the MNPs moiety. The fluorophore released from Fe3O4@SiO2 MNPs was fluorometrically measured, and the amount of fluorophore should be equivalent to the quantity of the NHS ester groups on the surface of Fe3O4@SiO2 MNPs that participated in the fluorophore conjugation reaction. Another sensitive and semiquantitative fluorescence microscopic test was also developed to confirm the presence of NHS ester groups on the surface of Fe3O4@SiO2 MNPs. Surface-conjugated NHS ester group measurements were primarily performed on Fe3O4@SiO2 MNPs of 100–150 nm in diameter and also on 20-nm nanoparticles of the same type but prepared by a different method. The efficiency of labeling native proteins by NHS ester-coated Fe3O4@SiO2 MNPs was explored in terms of maximizing the number of MNPs conjugated per BSA molecule or maximizing the number of BSA molecules conjugated per each nanoparticle. Maintaining the amount of fresh NHS ester moieties in the labeling reaction system was essential especially when maximizing the number of MNPs conjugated per protein molecule. The methodology demonstrated in this study can serve as a guide in labeling the exposed portions of proteins by bulky multivalent labeling reagents

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

    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. (paper)

  20. Magnetic hyperthermia and photothermal effect of functionalized Fe3O4 nanoparticles for biomedical applications

    Sadat, Md Ehsan; Shi, Donglu; Mast, David B.

    2014-03-01

    The heating of nanoparticle loaded tissue surrogates for potential applications in cancer therapy was achieved when the superparamagnetic Fe3O4 nanoparticles were subjected to either high frequency alternating (AC) magnetic fields or near infra-red (NIR) radiation. Four nanoparticles systems were studied, where each system was distinct in terms of the arrangement, surface modification and physical confinement of the Fe3O4 nanoparticles. It was observed that the thermal response of each nanoparticle system to AC magnetic fields was different and could be described in terms of linear response theory and by taking into account the dipole-dipole interaction for closely packed nanoparticle systems. It was also shown that the same nanoparticle systems could be effectively heated when illuminated with NIR radiation at 785 nm and 808 nm. The measured optical absorption and scattering of the Fe3O4 nanoparticle systems was analyzed in terms of Mie scattering theory. The overall results from this study clearly demonstrate that the temperature increase of Fe3O4 nanoparticle loaded tissue surrogate samples to therapeutic levels could be achieved using AC magnetic fields and NIR radiation.

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

    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.

  2. Recent advances in the synthesis of Fe3O4@AU core/shell nanoparticles

    Fe3O4@Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of “glue” material between the core and the shell. - Highlights: • Fe3O4 nanoparticles are promising for biomedical applications but have some disadvantages. • Covering Fe3O4 nanoparticles with Au shell leads to better stability and biocompatibility. • Core/shell nanoparticles are widely used for biomedical applications. • There are two types of Fe3O4@Au core/shell nanoparticles structures: bi-layer and multilayer composite. • Different synthetic methods enable production of nanoparticles of different sizes

  3. Tunable fluorescence enhancement based on bandgap-adjustable 3D Fe3O4 nanoparticles

    Hu, Fei; Gao, Suning; Zhu, Lili; Liao, Fan; Yang, Lulu; Shao, Mingwang

    2016-06-01

    Great progress has been made in fluorescence-based detection utilizing solid state enhanced substrates in recent years. However, it is still difficult to achieve reliable substrates with tunable enhancement factors. The present work shows liquid fluorescence enhanced substrates consisting of suspensions of Fe3O4 nanoparticles (NPs), which can assemble 3D photonic crystal under the external magnetic field. The photonic bandgap induced by the equilibrium of attractive magnetic force and repulsive electrostatic force between adjacent Fe3O4 NPs is utilized to enhance fluorescence intensity of dye molecules (including R6G, RB, Cy5, DMTPS-DCV) in a reversible and controllable manner. The results show that a maximum of 12.3-fold fluorescence enhancement is realized in the 3D Fe3O4 NP substrates without the utilization of metal particles for PCs/DMTPS-DCV (1.0 × 10‑7 M, water fraction (f w) = 90%).

  4. Magnetic Fe3O4 nanoparticle catalyzed chemiluminescence for detection of nitric oxide in living cells.

    Wang, Huiliang; Li, Mei; Wang, Bing; Wang, Meng; Kurash, Ibrahim; Zhang, Xiangzhi; Feng, Weiyue

    2016-08-01

    Direct and real-time measurement of nitric oxide (NO) in biological media is very difficult due to its transient nature. Fe3O4 nanoparticles (nanoFe3O4) because of their unique catalytic activities have attracted much attention as catalysts in a variety of organic and inorganic reactions. In this work, we have developed a magnetic Fe3O4 nanoparticle-based rapid-capture system for real-time detection of cellular NO. The basic principle is that the nanoFe3O4 can catalyze the decomposition of H2O2 in the system to generate superoxide anion (O2 (·-)) and the O2 (·-) can serve as an effective NO(·) trapping agent yielding peroxynitrite oxide anion, ONOO(-). Then the concentration of NO in cells can be facilely determined via peroxynitrite-induced luminol chemiluminescence. The linear range of the method is from 10(-4) to 10(-8) mol/L, and the detection of limit (3σ, n = 11) is as low as 3.16 × 10(-9) mol/L. By using this method, the NO concentration in 0.1 and 0.5 mg/L LPS-stimulated BV2 cells was measured as 4.9 and 11.3 μM, respectively. Surface measurements by synchrotron X-ray photoelectron spectroscopy (SRXPS) and scanning transmission X-ray microscopy (STXM) demonstrate the catalytic mechanism of the nanoFe3O4-based system is that the significantly excess Fe(II) exists on the surface of nanoFe3O4 and mediates the rapid heterogeneous electron transfer, thus presenting a new Fe2O3 phase on the surface. PMID:27289465

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

    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

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

    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. - Highlights: • Fe3O4 nanoparticles synthesized FeCl2 as the sole source by alkaline precipitation. • Hydrophilicity imparted to OA-Fe3O4 MNPs. • Improved heating induction ability. • Highly stabilized colloidal suspension. • Improved biocompatiblity

  7. Removal of Pb2+, Hg2+, and Cu2+ by Chain-Like Fe3O4@SiO2@Chitosan Magnetic Nanoparticles.

    Shi, Haowei; Yang, Junya; Zhu, Lizhong; Yang, Yuxiang; Yuan, Hongming; Yang, Yubing; Liu, Xiangnong

    2016-02-01

    In this paper, the chain-like core-shell structure Fe3O4@SiO2@Chitosan composite nanoparticles were synthesized by a two-step coating and following crosslinking glutaraldehyde on chitosan shell. The composite particles showed nearly monodisperse 105 sized particles with a core diameter of 80 nm and chitosan shell thickness of 12 nm. The synthesis conditions of the product were studied, and the morphology and properties of the composite nanoparticles were characterized by IR, XRD, TEM, SEM, EDS and VSM. The adsorption properties of Hg2+, Pb2+ or Cu2+ ions on Fe3O4, Fe3O4@SiO2 and the composite particles were in detail studied using the colorimetric method based on forming colored mercuric dithizone, rhodamine-Pb2+ complex and DDTC-Cu(2+) complex. The results showed, adsorption isotherm, kinetics and separation coefficient of heavy metal ions on these three magnetic nanoparticles were concerned with pH, metal ions' electronic configuration, silica coating and chitosan shell respectively. In addition, the recycle efficiency was also studied. The findings demonstrated that Fe3O4@SiO2@Chitosan composite nanoparticles have great application value in the adsorption and separation of heavy metal ions. PMID:27433691

  8. Effect of annealing temperature on magnetic phase transition in Fe3O4 nanoparticles

    Fe3O4 (magnetite) nanoparticles (NPs) were synthesized using a co-precipitation method, and then annealed at various temperatures between 50 and 850 °C for 1 h in air. After annealing, the NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The FTIR and XRD results indicated that Fe3O4 NPs were converted to γ-Fe2O3 (maghemite) by annealing at 250 °C for 1 h and then to α-Fe2O3 (hematite) on annealing in the range of 550–650 °C. The average crystallite size of the NPs estimated by the Debye–Scherrer equation increased from 6.6 to 37.6 nm by increasing annealing temperature from 50 to 850 °C. According to VSM results, the magnetite NPs were superparamagnetic and converted to the maghemite with superparamagnetic phase by annealing up to 550 °C. A phase transition from soft to hard ferromagnetic was occurred at annealing temperature 650 and 850 °C, respectively °C. This phase transition was attributed to the conversion of magnetite to hematite. The VSM analysis confirmed the XRD and FTIR results. The saturation magnetization (Ms) of Fe3O4 NPs was increased from 41.69 to 53.61 emu/g by increasing annealing temperature from 50 to 550 °C, and then decreased intensively to 0.49 emu/g after annealing at 850 °C. By increasing annealing temperature from 50 to 550, the crystallite size of NPs was increased from 6.6 to 12.7 and the coercive force (Hc) was reached to 4.20 Oe after annealing at 550 °C and then intensively increased to 1459.02 Oe for any further increasing of particle size up to 850 °C. - Highlights: • Fe3O4 nanoparticles (NPs) were synthesized using a co-precipitation method. • Prepared NPs annealed at 50, 250, 350, 450, 550, 650, 750, and 850°C for 1h in air. • Transform of superpara Fe3O4 to superpara γ-Fe2O3 occurred by annealing at 250 °C. • Superpara Fe3O4 transformed into α-Fe2O3, with soft ferromagnetic phase at 650 °C.

  9. Simple solvothermal synthesis of hydrophobic magnetic monodispersed Fe3O4 nanoparticles

    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.

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

    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...

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

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

    2013-06-01

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

  12. The Magnetorheological Finishing (MRF) of Potassium Dihydrogen Phosphate (KDP) Crystal with Fe3O4 Nanoparticles

    Ji, Fang; Xu, Min; Wang, Chao; Li, Xiaoyuan; Gao, Wei; Zhang, Yunfei; Wang, Baorui; Tang, Guangping; Yue, Xiaobin

    2016-01-01

    The cubic Fe3O4 nanoparticles with sharp horns that display the size distribution between 100 and 200 nm are utilized to substitute the magnetic sensitive medium (carbonyl iron powders, CIPs) and abrasives (CeO2/diamond) simultaneously which are widely employed in conventional magnetorheological finishing fluid. The removal rate of this novel fluid is extremely low compared with the value of conventional one even though the spot of the former is much bigger. This surprising phenomenon is gene...

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

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

    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 int...

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

    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.

  15. Seeded preparation of ultrathin FeS2 nanosheets from Fe3O4 nanoparticles

    Li, Tingting; Liu, Huiwen; Wu, Zhennan; Liu, Yi; Guo, Zuoxing; Zhang, Hao

    2016-06-01

    FeS2 nanomaterials with two-dimensional features hold great promise for electrochemical and photovoltaic applications. However, the preparation of ultrathin FeS2 nanosheets is still challenging because of the lack of a tailor-made approach. In this work, FeS2 nanosheets with a thickness of 2.1 nm are prepared through a Fe3O4-seeded approach. Uniform Fe3O4 nanoparticles are foremost synthesized via the standard method in organic media. The injection of a S solution leads to the replacement of O in Fe3O4 through anion-exchange, which generates (110) facet-enriched FeS2 nuclei. The subsequent (110) facet-mediated oriented attachment and fusion of FeS2 nuclei produce ultrathin FeS2 nanosheets. As catalysts in the hydrogen evolution reaction, FeS2 nanosheets exhibit good electrochemical activity.FeS2 nanomaterials with two-dimensional features hold great promise for electrochemical and photovoltaic applications. However, the preparation of ultrathin FeS2 nanosheets is still challenging because of the lack of a tailor-made approach. In this work, FeS2 nanosheets with a thickness of 2.1 nm are prepared through a Fe3O4-seeded approach. Uniform Fe3O4 nanoparticles are foremost synthesized via the standard method in organic media. The injection of a S solution leads to the replacement of O in Fe3O4 through anion-exchange, which generates (110) facet-enriched FeS2 nuclei. The subsequent (110) facet-mediated oriented attachment and fusion of FeS2 nuclei produce ultrathin FeS2 nanosheets. As catalysts in the hydrogen evolution reaction, FeS2 nanosheets exhibit good electrochemical activity. Electronic supplementary information (ESI) available: EDX, AFM images, small-angle XRD pattern, SAED pattern, and TEM images of FeS2 nanosheets. See DOI: 10.1039/c6nr02211a

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

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

  17. Ultrafast Preparation of Monodisperse Fe3 O4 Nanoparticles by Microwave-Assisted Thermal Decomposition.

    Liang, Yi-Jun; Zhang, Yu; Guo, Zhirui; Xie, Jun; Bai, Tingting; Zou, Jiemeng; Gu, Ning

    2016-08-01

    Thermal decomposition, as the main synthetic procedure for the synthesis of magnetic nanoparticles (NPs), is facing several problems, such as high reaction temperatures and time consumption. An improved a microwave-assisted thermal decomposition procedure has been developed by which monodisperse Fe3 O4 NPs could be rapidly produced at a low aging temperature with high yield (90.1 %). The as-synthesized NPs show excellent inductive heating and MRI properties in vitro. In contrast, Fe3 O4 NPs synthesized by classical thermal decomposition were obtained in very low yield (20.3 %) with an overall poor quality. It was found for the first time that, besides precursors and solvents, magnetic NPs themselves could be heated by microwave irradiation during the synthetic process. These findings were demonstrated by a series of microwave-heating experiments, Raman spectroscopy and vector-network analysis, indicating that the initially formed magnetic Fe3 O4 particles were able to transform microwave energy into heat directly and, thus, contribute to the nanoparticle growth. PMID:27381301

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

    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. - Graphical abstract: Covalently grafted polyethyleneimine on Fe3O4 magnetic nanoparticles as easily reusable catalyst for the synthesis of various 4H-pyrans. - Highlights: • Polyethyleneimine modified Fe3O4 via covalent bonding as a novel water tolerance catalyst. • The catalyst showed high efficiency for one-pot synthesis of 2-amino-3-cyano-4H-pyrans in water. • Catalysts could be easily recovered and reused for several times without a significant loss in their catalytic activity

  19. Heat treatment effects on Fe3O4 nanoparticles structure and magnetic properties prepared by carbothermal reduction

    Research highlights: → This manuscript reports for the first time to study the effects of the heating temperatures and holding time on crystalline phase composition and magnetic properties of Fe3O4 nanoparticles prepared by carbothermal reduction method using glucose as carbon source both theoretically and experimentally. → This study is helpful for controlled synthesis of pure Fe3O4 with the carbothermal reduction method by controlling right temperature and time. → Fe3O4 powder heated at 650 deg. C for 2 h has the highest saturation magnetization (Ms = 97.99 emu/g), higher than Fe3O4 prepared by other techniques due to better crystallinity and expanded crystalline cell. - Abstract: Fe3O4 nanoparticles were prepared by carbothermal reduction method using glucose as carbon source. Heating temperature and holding time effects on crystalline phase composition and magnetic properties of Fe3O4 nanoparticles were investigated by X-ray diffraction, field-emission scanning electron microscopy and vibrating sample magnetometer. Pure Fe3O4 nanoparticles with an average crystallite size of 48 nm was obtained at higher heating temperature of 650 deg. C and shorter holding time of 0.5 h, or at lower heating temperature of 450 deg. C and longer holding time of more than 6 h. The crystallite size of Fe3O4 nanoparticles increases with heating temperature and holding time. Fe3O4 nanoparticles heated at 650 deg. C for 2 h have the highest saturation magnetization (Ms = 97.99 emu g-1), higher than Fe3O4 prepared by other techniques due to better microstructure, crystallinity and expanded crystalline cell.

  20. A selective nanocatalyst for an efficient Ugi reaction: Magnetically recoverable Cu(acac)2/NH2-T/SiO2@Fe3O4 nanoparticles

    Monireh Ghavami; Maryam Koohi; Mohammad Zaman Kassaee

    2013-11-01

    A novel, magnetically recoverable nanocatalyst is fabricated through simple immobilization of copper(II) acetylacetonate on the surface of amine-terminated silica-coated Fe3O4 nanoparticles: Cu(acac)2/NH2-T/SiO2@Fe3O4NPs. Unambiguous bonding of Cu to the terminal amine is indicated by Xray photoelectron spectroscopy (XPS). Further characterizations are carried out by different techniques. Selectivity of this catalyst is demonstrated through one-pot synthesis of fourteen α-aminoacyl amides using Ugi four-component reaction of cyclohexyl isocyanide, acetic acid, amines and various aldehydes. Interestingly, all aromatic aldehydes react with short reaction times and high yields, but heteroaromatic aldehydes do not yield any product. Catalyst efficiency remains unaltered through three consecutive experiments.

  1. Micro-optical coherence tomography tracking of magnetic gene transfection via Au-Fe3O4 dumbbell nanoparticles

    Shi, Wei; Liu, Xinyu; Wei, Chao; Xu, Zhichuan J.; Sim, Stanley Siong Wei; Liu, Linbo; Xu, Chenjie

    2015-10-01

    Heterogeneous Au-Fe3O4 dumbbell nanoparticles (NPs) are composed of Au NPs and Fe3O4 NPs that bring in optical and magnetic properties respectively. This article reports the engineering of Au-Fe3O4 NPs as gene carriers for magnetic gene transfection as well as contrast agents for micro-optical coherence tomography (μOCT). As a proof-of-concept, Au-Fe3O4 NPs are used to deliver the green fluorescent protein to HEK 293T cells and their entrance into the cells is monitored through μOCT.Heterogeneous Au-Fe3O4 dumbbell nanoparticles (NPs) are composed of Au NPs and Fe3O4 NPs that bring in optical and magnetic properties respectively. This article reports the engineering of Au-Fe3O4 NPs as gene carriers for magnetic gene transfection as well as contrast agents for micro-optical coherence tomography (μOCT). As a proof-of-concept, Au-Fe3O4 NPs are used to deliver the green fluorescent protein to HEK 293T cells and their entrance into the cells is monitored through μOCT. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05459a

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

    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 μg/mL. However, the combination of umbelliprenin and Fe3O4 MNPs showed the IC50 value of 9 μg/mL. In other words, cell proliferation decreased to the remarkably-low proportion of 45% after treating cells with umbelliprenin-coated Fe3O4 MNPs. This suggests that with the aid of nanoparticles as carriers, natural products may have even broader range of medical applications in future.

  3. Magnetic hyperthermia in brick-like Ag@Fe3O4 core-shell nanoparticles

    Brollo, M. E. F.; Orozco-Henao, J. M.; López-Ruiz, R.; Muraca, D.; Dias, C. S. B.; Pirota, K. R.; Knobel, M.

    2016-01-01

    Heating efficiency of multifunctional Ag@Fe3O4 brick-like nanoparticles under alternating magnetic field was investigated by means of specific absorption rate (SAR) measurements, and compared with equivalent measurements for plain magnetite and dimer heteroparticles. The samples were synthesized by thermal decomposition reactions and present narrow size polydispersity and high degree of crystallinity. The SAR values are analyzed using the superparamagnetic theory, in which the basic morphology, size and dispersion of sizes play key roles. The results suggest that these novel brick-like nanoparticles are good candidates for hyperthermia applications, displaying heating efficiencies comparable with the most efficient plain nanoparticles.

  4. Recent advances in the synthesis of Fe3O4@AU core/shell nanoparticles

    Salihov, Sergei V.; Ivanenkov, Yan A.; Krechetov, Sergei P.; Veselov, Mark S.; Sviridenkova, Natalia V.; Savchenko, Alexander G.; Klyachko, Natalya L.; Golovin, Yury I.; Chufarova, Nina V.; Beloglazkina, Elena K.; Majouga, Alexander G.

    2015-11-01

    Fe3O4@Au core/shell nanoparticles have unique magnetic and optical properties. These nanoparticles are used for biomedical applications, such as magnetic resonance imaging, photothermal therapy, controlled drug delivery, protein separation, biosensors, DNA detection, and immunosensors. In this review, recent methods for the synthesis of core/shell nanoparticles are discussed. We divided all of the synthetic methods in two groups: methods of synthesis of bi-layer structures and methods of synthesis of multilayer composite structures. The latter methods have a layer of "glue" material between the core and the shell.

  5. Preparation and properties of bio-compatible magnetic Fe3O4 nanoparticles

    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

  6. Electrostatic self-assembly of Fe 3O 4 nanoparticles on carbon nanotubes

    Liu, Yong; Jiang, Wei; Li, Song; Li, Fengsheng

    2009-06-01

    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 Fe 3O 4 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 Fe 3O 4/CNTs. The Fe 3O 4/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.

  7. The Magnetorheological Finishing (MRF) of Potassium Dihydrogen Phosphate (KDP) Crystal with Fe3O4 Nanoparticles

    Ji, Fang; Xu, Min; Wang, Chao; Li, Xiaoyuan; Gao, Wei; Zhang, Yunfei; Wang, Baorui; Tang, Guangping; Yue, Xiaobin

    2016-02-01

    The cubic Fe3O4 nanoparticles with sharp horns that display the size distribution between 100 and 200 nm are utilized to substitute the magnetic sensitive medium (carbonyl iron powders, CIPs) and abrasives (CeO2/diamond) simultaneously which are widely employed in conventional magnetorheological finishing fluid. The removal rate of this novel fluid is extremely low compared with the value of conventional one even though the spot of the former is much bigger. This surprising phenomenon is generated due to the small size and low saturation magnetization ( M s) of Fe3O4 and corresponding weak shear stress under external magnetic field according to material removal rate model of magnetorheological finishing (MRF). Different from conventional D-shaped finishing spot, the low M s also results in a shuttle-like spot because the magnetic controllability is weak and particles in the fringe of spot are loose. The surface texture as well as figure accuracy and PSD1 (power spectrum density) of potassium dihydrogen phosphate (KDP) is greatly improved after MRF, which clearly prove the feasibility of substituting CIP and abrasive with Fe3O4 in our novel MRF design.

  8. The Magnetorheological Finishing (MRF) of Potassium Dihydrogen Phosphate (KDP) Crystal with Fe3O4 Nanoparticles.

    Ji, Fang; Xu, Min; Wang, Chao; Li, Xiaoyuan; Gao, Wei; Zhang, Yunfei; Wang, Baorui; Tang, Guangping; Yue, Xiaobin

    2016-12-01

    The cubic Fe3O4 nanoparticles with sharp horns that display the size distribution between 100 and 200 nm are utilized to substitute the magnetic sensitive medium (carbonyl iron powders, CIPs) and abrasives (CeO2/diamond) simultaneously which are widely employed in conventional magnetorheological finishing fluid. The removal rate of this novel fluid is extremely low compared with the value of conventional one even though the spot of the former is much bigger. This surprising phenomenon is generated due to the small size and low saturation magnetization (M s) of Fe3O4 and corresponding weak shear stress under external magnetic field according to material removal rate model of magnetorheological finishing (MRF). Different from conventional D-shaped finishing spot, the low M s also results in a shuttle-like spot because the magnetic controllability is weak and particles in the fringe of spot are loose. The surface texture as well as figure accuracy and PSD1 (power spectrum density) of potassium dihydrogen phosphate (KDP) is greatly improved after MRF, which clearly prove the feasibility of substituting CIP and abrasive with Fe3O4 in our novel MRF design. PMID:26858161

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

    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.

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

    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.

  11. Core-shell-corona doxorubicin-loaded superparamagnetic Fe3O4 nanoparticles for cancer theranostics.

    Semkina, A; Abakumov, M; Grinenko, N; Abakumov, A; Skorikov, A; Mironova, E; Davydova, G; Majouga, A G; Nukolova, N; Kabanov, A; Chekhonin, V

    2015-12-01

    Superparamagnetic iron oxide magnetic nanoparticles (MNPs) are successfully used as contrast agents in magnetic-resonance imaging. They can be easily functionalized for drug delivery functions, demonstrating great potential for both imaging and therapeutic applications. Here we developed new pH-responsive theranostic core-shell-corona nanoparticles consisting of superparamagentic Fe3O4 core that displays high T2 relaxivity, bovine serum albumin (BSA) shell that binds anticancer drug, doxorubicin (Dox) and poly(ethylene glycol) (PEG) corona that increases stability and biocompatibility. The nanoparticles were produced by adsorption of the BSA shell onto the Fe3O4 core followed by crosslinking of the protein layer and subsequent grafting of the PEG corona using monoamino-terminated PEG via carbodiimide chemistry. The hydrodynamic diameter, zeta-potential, composition and T2 relaxivity of the resulting nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, thermogravimetric analysis and T2-relaxometry. Nanoparticles were shown to absorb Dox molecules, possibly through a combination of electrostatic and hydrophobic interactions. The loading capacity (LC) of the nanoparticles was 8 wt.%. The Dox loaded nanoparticles release the drug at a higher rate at pH 5.5 compared to pH 7.4 and display similar cytotoxicity against C6 and HEK293 cells as the free Dox. PMID:26595387

  12. Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications

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

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

    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

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

    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.

  15. Study on Electromagnetorheological Fluid Containing CuPc-Fe3O4 Nanoparticles Composite

    2002-01-01

    Electromagnetorheological(EMR) fluids containing CuPc-Fe3O4 nanopareticles composite were prepared and their properties were studied.The results show that Δτ of this kind of EMR fluids increases with the increments of applied electric field, magnetic field and volume fraction of the nanoparticles composite. Δτ has an approximate linear relationship with γ.When an electric and magnetic field are applied simultaneously,the EMR fluids have a synergistic effect. The EMR fluids have a good long-term stability.

  16. Multifunctional polypyrrole@fe3o4 nanoparticles for dual-modal imaging and in vivo photothermal cancer therapy

    Tian, Qiwei

    2013-11-27

    Magnetic Fe3O4 crystals are produced in situ on preformed polypyrrole (PPY) nanoparticles by rationally converting the residual Fe species in the synthetic system. The obtained PPY@Fe3O4 composite nanoparticles exhibit good photostability and biocompatibility, and they can be used as multifunctional probes for MRI, thermal imaging, and photothermal ablation of cancer cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Fabrication of Fe3O4@mSiO2 Core-Shell Composite Nanoparticles for Drug Delivery Applications

    Uribe Madrid, Sergio I.; Pal, Umapada; Kang, Young Soo; Kim, Junghoon; Kwon, Hyungjin; Kim, Jungho

    2015-05-01

    We report the synthesis of Fe3O4@mSiO2 nanostructures of different meso-silica (mSiO2) shell thickness, their biocompatibility and behaviors for loading and release of a model drug ibuprofen. The composite nanostructures have superparamagnetic magnetite cores of 208 nm average size and meso-silica shells of 15 to 40 nm thickness. A modified Stöber method was used to grow the meso-silica shells over the hydrothermally grown monodispersed magnetite particles. The composite nanoparticles show very promising drug holding and releasing behaviors, which depend on the thickness of meso-silica shell. The biocompatibility of the meso-silica-coated and uncoated magnetite nanoparticles was tested through cytotoxicity assay on breast cancer (MCF-7), ovarian cancer (SKOV3), normal human lung fibroblasts MRC-5, and IMR-90 cells. The high drug holding capacity and reasonable biocompatibility of the nanostructures make them ideal agents for targeted drug delivery applications in human body.

  18. The Preparation of Glucan-Fe3O4 Magnetic Nanoparticles and Its In Vivo Distribution in Mice

    Fengdan Jin

    2014-01-01

    Full Text Available The glucan-Fe3O4 magnetic nanoparticles were prepared by hydrothermal method. The mixture of FeCl2 and glucan was stirred vigorously for half an hour under low temperature (15°C. KOH of 1 mol/L was dropwise added, slowly, into the solution until the pH to 12. Immediately, KNO3 was added and the temperature was raised to 75°C for an hour. All the processes of Fe3O4 crystal particles generation were under nitrogen. An atomic absorption spectrometry quantitative analysis method was built to determine the in vivo distribution of the glucan-Fe3O4 magnetic nanoparticles in mice. The diameter of glucan-Fe3O4 magnetic nanoparticles was about 25 nm and they were up taken by the liver primarily after intravenous administration via the tail.

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

    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.

  20. Ethylene glycol methacrylate phosphate coated Fe3O4 nanoparticles for selective separation of plutonium

    Recovery of lanthanides and actinides from high level nuclear waste is an area of world-wide concern. Recently, interest has been focused on magnetic fluidized bed separation technology and the development of magnetically assisted chemical separation (MACS) systems for nuclear waste remediation. The magnetic-sorbent have larger surface area, can be quickly recovered from the medium using external magnetic field, and secondary waste is not generated. However, sorption selectivity and efficiency of these materials towards targeted radionuclides have still scope for improvement. Ethylene glycol methacrylate phosphate takes up actinides. Yudhisthira Sahoo and co-workers demonstrates that alkyl phosphonates and phosphates bind efficiently to iron oxide particle surfaces and can serve, in general, as potential alternatives to fatty acids as coating agents for oxide nanoparticles. In the present work, 0.1 g of Fe3O4 nanoparticles (20-30 nm) were dispersed in 10 mL 0.1 M Ethylene glycol methacrylate phosphate (EGMP) solution in methanol at room temperature under shaking condition for 24 h. Organic layer is then removed and the particles were washed 3 times with 1 mL methanol. It was the dried in air at room temperature overnight. Weighed amount of EGMP coated Fe3O4 nanoparticles were equilibrated with 241Am, 233U or 239Pu activity spiked in feed having acid concentration varying from 0.01-3.0 M HNO3

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

    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 γ-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

  2. Characterization of the magnetic Fe3O4 nanoparticles prepared by gamma irradiation

    In this study, gamma irradiation treatment has been applied for preparation of the magnetic nanoparticles from iron(III) chloride (FeCl3). Structure of the resulting black powders were characterized with X-ray diffraction (XRD). The results revealed that the products prepared by gamma irradiation were mainly magnetite (Fe3O4) instead of maghemite (Fe2O3). The basic characteristics of the magnetite nanoparticles such as their particle size and magnetic properties were investigated using scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The nanoparticles showed superparamagnetism with the saturated magnetization of about 48.6 emu/g. Influences of radiation conditions on radiation preparation of magnetite nanoparticles and their properties were also discussed. Reaction yield increased, while average diameter of the obtained nanoparticles reduced from 46 to 17 nm depended on the absorbed dose. (author)

  3. Preparation and characterization of biofunctionalized chitosan/Fe3O4 magnetic nanoparticles for application in liver magnetic resonance imaging

    Biofunctionalized chitosan@Fe3O4 nanoparticles are synthesized by combining Fe3O4 and CS chemically modified with PEG and lactobionic acid in one step. The biofunctionalized nanoparticles are characterized by TEM, X-ray, DLS, zeta-potential and magnetic measurements. The in vitro and in vivo behaviors of the biofunctionalized nanoparticles, especially, the cytotoxicity, the protein resistance, metabolism and iron toxicity are assessed. The functional groups, PEG enable the nanoparticles more biocompatible and the lactobionic acid groups enable liver targeting. The potential applications of the nanoparticles in liver magnetic resonance imaging are confirmed. The results demonstrated that the nanoparticles are suspension stability, non-cytotoxicity, non-tissue toxicity and sensitive in liver magnetic resonance imaging, representing potential tools for applications in the biomedical field. - Highlights: • Biofunctionalized PEG/LA-CS@Fe3O4 NPs were prepared in one step. • PEG/LA-CS@Fe3O4 NPs show excellent monodispersity and suspension stability. • PEG/LA-CS@Fe3O4 NPs show excellent biocompatibility. • PEG/LA-CS/Fe3O4 NPs are efficiently used in liver magnetic resonance imaging

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

    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.

  5. Glucose sensor based on Fe3 O4-PEI nanoparticles%基于Fe3 O4-PEI纳米粒子构建葡萄糖传感器的研究

    何传新; 任圣颖; 谢敏随; 袁安朋; 洪飞; 张黔玲; 刘剑洪

    2015-01-01

    Fe3O4-PEI nanoparticles with Fe3O4 core and polyethylenimine (PEI) shell were prepared via the co-precipitation method. Results from scanning electron microscope ( SEM ) and transmission electron microscope ( TEM) show that Fe3 O4-PEI nanoparticles present globular shape with almost uniform diameters of about 25 nm. Magnetic hysteresis loops of Fe3 O4-PEI and Fe3 O4 nanoparticles were obtained by a vibrating sample magnetometer ( VSM) . The magnetism of Fe3 O4 nanoparticles still remains a lot after coating with PEI, and the saturation magneti-zation value of Fe3 O4-PEI nanoparticles is 38. 2 emu/g. Thermogravimetry ( TG) analysis indicats that the loading amount of PEI on the surface of Fe3 O4 nanoparticles is about 23. 26%. The glucose oxidase ( GOx) enzyme was im-mobilized on the Fe3 O4-PEI nanoparticles surface by electrostatic interaction. Fe3 O4-PEI-GOx/Pt glucose sensor was prepared with platinum ( Pt) as its basal electrode, which exhibits a good electrochemical catalysis for glucose, high sensitivity, strong anti-interference ability and long-term durability for glucose detection under an optimal preparation condition.%采用共沉淀法制备核层为四氧化三铁( Fe3 O4)壳层为聚乙烯亚胺( polyethyleneimine, PEI)的磁性复合纳米粒子Fe3 O4-PEI.扫描电子显微镜和透射电子显微镜表征结果显示,制备的磁性复合纳米粒子Fe3 O4-PEI粒径均匀,直径约为25 nm.通过振动样品磁强计比较Fe3 O4-PEI和Fe3 O4纳米粒子的磁滞回线,结果表明,经PEI包覆后复合纳米粒子饱和磁化值为38.2 emu/g,仍具有较好的磁性.热重分析表明,包覆在Fe3 O4纳米粒子表面的PEI质量分数约为23.26%.通过静电作用,实现了Fe3 O4-PEI复合纳米粒子对葡萄糖氧化酶的负载,以铂电极为基底电极,制备了Fe3 O4-PEI-GOx/Pt葡萄糖传感器.在最优测试条件下,该修饰电极对葡萄糖表现出优异的电化学催化性能,具有灵敏度高、抗干扰能力强、稳定性好的特点.

  6. Contribution of Fe3O4 nanoparticles to the fouling of ultrafiltration with coagulation pre-treatment

    Yu, Wenzheng; Xu, Lei; Graham, Nigel; Qu, Jiuhui

    2015-08-01

    A coagulation (FeCl3)-ultrafiltration process was used to treat two different raw waters with/without the presence of Fe3O4 nanoparticle contaminants. The existence of Fe3O4 nanoparticles in the raw water was found to increase both irreversible and reversible membrane fouling. The trans-membrane pressure (TMP) increase was similar in the early stages of the membrane runs for both raw waters, while it increased rapidly after about 15 days in the raw water with Fe3O4 nanoparticles, suggesting the involvement of biological effects. Enhanced microbial activity with the presence of Fe3O4 nanoparticles was evident from the measured concentrations of extracellular polymeric substances (EPS) and deoxyribonucleic acid (DNA), and fluorescence intensities. It is speculated that Fe3O4 nanoparticles accumulated in the cake layer and increased bacterial growth. Associated with the bacterial growth is the production of EPS which enhances the bonding with, and between, the coagulant flocs; EPS together with smaller sizes of the nano-scale primary particles of the Fe3O4-CUF cake layer, led to the formation of a lower porosity, more resilient cake layer and membrane pore blockage.

  7. Fe3O4/salicylic acid nanoparticles versatility in magnetic mediated vascular nanoblockage

    An aqueous dispersion of Fe3O4/salicylic acid magnetic nanoparticles (SaMNPs) was synthesized by a modified Massart method, characterized by Inductively Coupled Plasma–Optic Emission Spectrometry (ICP-OES), High-Resolution Transmission Electron Microscopy (HRTEM) and Dynamic Light Scattering (DLS) methods, and tested on the chick chorioallantoic membrane (CAM) model to evaluate biocompatibility, biodistribution, intravascular time persistence, and ability to be magnetically target driven in order to block the blood supply into a tumor xenograft. ICP-OES, DLS, and HRTEM SaMNPs sample analyses showed a 0.356 mg/mL Fe concentration, a good stability in water (average Zeta potential of 39.3 mV), a hydrodynamic diameter around 52 nm and a core diameter in the 7–15 nm range for the Fe3O4 nanoparticles. In vivo CAM assay showed that SaMNPs were biocompatible with the chick embryo, were fixed almost completely by the liver, had no embolic potential, and a threshold-dose-dependent intravascular magnetic targeting time. Study on the CAM tumor model showed that SaMNPs could be used for long-term magnetically mediated nanoblocking of the capillary networks and 70-µm smaller arterioles

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

    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.

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

    Lin, Jing-Fung; Wang, Chia-Hung; Lee, Meng-Zhe

    2013-04-01

    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.

  10. Magnetic Behaviour and Heating Effect of Fe3O4 Ferrofluids Composed of Monodisperse Nanoparticles

    ZHANG Li-Ying; DOU Yong-Hua; ZHANG Ling; GU Hong-Chen

    2007-01-01

    Fe3O4 ferrofluids containing monodisperse Fe3O4 nanoparticles with different diameters of 8, 12, 16 and 18 nm are prepared by using high-temperature solution phase reaction. The particles have single crystal structures with narrow size distributions. At room temperature, the 8-nm ferrofluid shows superparamagnetic behaviour,whereas the others display hysteresis properties and the coercivity increases with the increasing particle size.The spin glass-like behaviour and cusps near 190K are observed on all ferrofluids according to the temperature variation of field-cooled (FC) and zero-field-cooled (ZFC) magnetization measurements. The cusps are found to be associated with the freezing point of the solvent. As a comparison, the ferrofluids are dried and the FC and ZFC magnetization curves of powdery samples are also investigated. It is found that the blocking temperatures for the powdery samples are higher than those for their corresponding ferrofluids. Moreover, the size dependent heating effect of the ferrofluids is also investigated in ac magnetic field with a frequency of 55 kHz and amplitude of 200 Oe.

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

    Altan, Cem L; Bucak, Seyda

    2011-07-15

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

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

    Altan, Cem L.; Bucak, Seyda

    2011-07-01

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

  13. Line Narrowing in Mössbauer Spectra of Superparamagnetic Fe3O4 Nanoparticles

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

  14. Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold

    Feygenson, Mikhail; Bauer, John C.; Gai, Zheng; Marques, Carlos; Aronson, Meigan C.; Teng, Xiaowei; Su, Dong; Stanic, Vesna; Urban, Volker S.; Beyer, Kevin A.; Dai, Sheng

    2015-08-10

    We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wustite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite

  15. Colorimetric aptasensing of ochratoxin A using Au@Fe3O4 nanoparticles as signal indicator and magnetic separator.

    Wang, Chengquan; Qian, Jing; Wang, Kun; Yang, Xingwang; Liu, Qian; Hao, Nan; Wang, Chengke; Dong, Xiaoya; Huang, Xingyi

    2016-03-15

    Gold nanoparticles (Au NPs) doped Fe3O4 (Au@Fe3O4) NPs have been synthesized by a facile one-step solvothermal method. The peroxidase-like activity of Au@Fe3O4 NPs was effectively enhanced due to the synergistic effect between the Fe3O4 NPs and Au NPs. On this basis, an efficient colorimetric aptasensor has been developed using the intrinsic dual functionality of the Au@Fe3O4 NPs as signal indicator and magnetic separator. Initially, the amino-modified aptamer specific for a typical mycotoxin, ochratoxin A (OTA), was surface confined on the amino-terminated glass beads surafce using glutaraldehyde as a linker. Subsequently, the amino-modified capture DNA (cDNA) was labeled with the amino-functionalized Au@Fe3O4 NPs and the aptasensor was thus fabricated through the hybridization reaction between cDNA and the aptamers. While upon OTA addition, aptamers preferred to form the OTA-aptamer complex and the Au@Fe3O4 NPs linked on the cDNA were released into the bulk solution. Through a simple magnetic separation, the collected Au@Fe3O4 NPs can produce a blue colored solution in the presence of 3,3',5,5'-tetramethylbenzidine and H2O2. When the reaction was terminated by addition of H(+) ions, the blue product could be changed into a yellow one with higher absorption intensity. This colorimetric aptasensor can detect as low as 30 pgmL(-1) OTA with high specificity. To the best of our knowledge, the present colorimetric aptasensor is the first attempt to use the peroxidase-like activity of nanomaterial for OTA detection, which may provide an acttractive path toward routine quality control of food safety. PMID:26583358

  16. Preparation and photocatalytic properties of magnetically reusable Fe3O4@ZnO core/shell nanoparticles

    Wang, Jian; Yang, Jinghai; Li, Xiuyan; Wang, Dandan; Wei, Bing; Song, Hang; Li, Xuefei; Fu, Siwei

    2016-01-01

    Fe3O4@ZnO binary nanoparticles were synthesized by a simple two-step chemical method and characterized using various analytical instruments. TEM result proved the binary nanoparticles have core/shell structures and average particle size is 60 nm. Photocatalytic investigation of Fe3O4@ZnO core/shell nanoparticles was carried out using rhodamine B (RhB) solution under UV light. Fe3O4@ZnO core/shell nanoparticles showed enhanced photocatalytic performance in comparison with the as prepared ZnO nanoparticles. The enhanced photocatalytic activity for Fe3O4@ZnO might be resulting from the higher concentration of surface oxygen vacancies and the suppressing effect of the Fe3+ ions on the recombination of photoinduced electron-hole pairs. Magnetization saturation value (5.96 emu/g) of Fe3O4@ZnO core/shell nanoparticles is high enough to be magnetically removed by applying a magnetic field. The core/shell photocatalyst can be easily separated by using a commercial magnet and almost no decrease in photocatalytic efficiency was observed even after recycling six times.

  17. Structural and magnetic properties of Fe3O4 nanoparticles prepared by arc-discharge in water

    2007-01-01

    By using a simple and low-cost arc-discharge method in deionized water, high purity Fe3O4 nanoparticles have been synthesized on large scale. The structure of these nanoparticles has been studied by means of transmission electron microscope and X-ray diffraction. The synthesized Fe3O4 nanoparticles show well-defined spherical shape, with diameters ranging from 10 to 30 nm and the average diameter about 20 nm. By investigating the effects of the different processing conditions, optimum parameters were obtained. Moreover, the size of the as-grown nanoparticles can also be controlled through adjusting the processing parameters. These Fe3O4 nanoparticles were magnetic materials, showing saturation magnetization of 64.97 emu/g at room temperature.

  18. Preparation of Fe3O4/TiO2 nanoparticles by microemulsion%微乳液法制备Fe3O4/TiO2磁性纳米粒子

    杜雪岩; 马芬; 李芳; 徐凯; 史世毅

    2011-01-01

    The Fe3O4 magnetic nanoparticles with the average particle size of about 6.0 nm were prepared by a polyol reduction method.Fe3O4/TiO2 nanoparticles were synthesized in a OP-10/n-butanol/cyelohexane/ammonia reverse microemulsion system by using of as-prepared Fe3O4 nanoparticles as cores.The composite nanoparticles were characterized by X-ray powder diffraction (XRD) , transmission electron microscopy (TEM) ,and vibrating sample magnetometer ( VSM).The results showed that the primary titanium dioxide coated successfully on the surface of Fe3O4 nanoparticles.After coating performance, their saturation magnetization decreased significantly, while their coercivity was also close to zero indicating super-paramagnetic properties.%采用多元醇还原法制备出平均粒径为6.0 nm的Fe3O4磁性纳米粒子,以此磁性纳米粒子为核,在OP-10/正丁醇/环己烷/浓氨水反向微乳体系中制备出Fe3O4/TiO2磁性纳米复合粒子,通过XRD,TEM,VSM对复合籽子进行性能表征.结果表明,采用微乳液法能够制备出Fe3O4/TiO2磁性纳米复合粒子,并且包覆后比饱和磁化强度有所下降,但矫顽力仍趋近于0,显示超顺磁性.

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

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

    2010-02-01

    Water-soluble l-arginine-capped Fe3O4 nanoparticles were synthesized using a one-pot and green method. Nontoxic, renewable and inexpensive reagents including FeCl3, l-arginine, glycerol and water were chosen as raw materials. Fe3O4 nanoparticles show different dispersive states in acidic and alkaline solutions for the two distinct forms of surface binding l-arginine. Powder X-ray diffraction and X-ray photoelectron spectroscopy were used to identify the structure of Fe3O4 nanocrystals. The products behave like superparamagnetism at room temperature with saturation magnetization of 49.9 emu g-1 and negligible remanence or coercivity. In the presence of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride, the anti-chloramphenicol monoclonal antibodies were connected to the l-arginine-capped magnetite nanoparticles. The as-prepared conjugates could be used in immunomagnetic assay.

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

    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-glycero-3-phosphocholine (DPPC) and l-α-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

  1. Preparation of nanosized hollow silica spheres from Na2SiO3 using Fe3O4 nanoparticles as templates

    Chun Liu; Aili Wang; Hengbo Yin; Yutang Shen; Tingshun Jiang

    2012-01-01

    Nanosized hollow silica spheres with average diameters from 43 to 70nm were prepared by removal of Fe3O4 templates with hydrochloric acid from silica-coated Fe3O4 core-shell composites.The shells of the hollow silica spheres had nanopores with average diameters of 0.92-1.25 nm.When the silica-coated Fe3O4 core-shell composites were prepared at a high pH value or with a low mole ratio of Na2SiO3 to Fe3O4,the resulting hollow silica spheres consisted of highly porous shells.When the silica-coated Fe3O4 core-shell composites were prepared with a high mole ratio of Na2SiO3 to Fe3O4,the resulting hollow silica spheres had large diameters and thick shells.The release rate of herbicide,ammonium glyphosate,could be tuned by using hollow silica spheres with different shell thicknesses.

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

    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

  3. Shape-Controllable Synthesis of Peroxidase-Like Fe3O4 Nanoparticles for Catalytic Removal of Organic Pollutants

    Wan, Dong; Li, Wenbing; Wang, Guanghua; Wei, Xiaobi

    2016-08-01

    The shape of Fe3O4 nanoparticles is controlled using a simple oxidation-precipitation method without any surfactant. The morphology and structure of the obtained Fe3O4 nanoparticles were characterized by using x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, N2 physisorption and vibrating sample magnetometer. As-prepared Fe3O4 samples showed octahedron, cube, hexagonal plate and sphere morphologies. Peroxidase-like activity of the four nanostructures was evaluated for catalytic removal of organic pollutants in the presence of H2O2, using rhodamine B as a model compound. The results showed that the H2O2-activating ability of the Fe3O4 nanocrystals was structure dependent and followed the order sphere > cube > octahedron > hexagonal plate, which was closely related to their surface FeII/FeIII ratios or crystal planes. The reusability of Fe3O4 spheres was also investigated after five successive runs, which demonstrated the promising application of the catalyst in the degradation of organic pollutants. This investigation is of great significance for the heterogeneous catalysts with enhanced activity and practical application.

  4. One-step solvothermal synthesis of Fe3O4-C core–shell nanoparticles with tunable sizes

    We report the synthesis of Fe3O4-C core–shell nanoparticles (FCNPs) by using a facile one-step solvothermal method. The FCNPs consisted of Fe3O4 particles as the cores and amorphous uniform carbon shells. The content of Fe3O4 is up to 81.6 wt%. These core–shell nanoparticles are aggregated by primary nanocrystals with a size of 10–12 nm. The FCNPs possess a hollow interior, high magnetization, excellent absorption properties and abundant surface hydroxyl groups. A possible growth mechanism of the FCNPs is proposed. The role of glucose in regulating the grain size and morphology of the particles is discussed. The absorption properties of the FCNPs towards Cr(VI) in aqueous solution is investigated. We demonstrate that the FCNPs can effectively remove more than 90 wt% of Cr(VI) from aqueous solution. (paper)

  5. One-step solvothermal synthesis of Fe3O4@C core-shell nanoparticles with tunable sizes

    Zheng, J.; Liu, Z. Q.; Zhao, X. S.; Liu, M.; Liu, X.; Chu, W.

    2012-04-01

    We report the synthesis of Fe3O4@C core-shell nanoparticles (FCNPs) by using a facile one-step solvothermal method. The FCNPs consisted of Fe3O4 particles as the cores and amorphous uniform carbon shells. The content of Fe3O4 is up to 81.6 wt%. These core-shell nanoparticles are aggregated by primary nanocrystals with a size of 10-12 nm. The FCNPs possess a hollow interior, high magnetization, excellent absorption properties and abundant surface hydroxyl groups. A possible growth mechanism of the FCNPs is proposed. The role of glucose in regulating the grain size and morphology of the particles is discussed. The absorption properties of the FCNPs towards Cr(VI) in aqueous solution is investigated. We demonstrate that the FCNPs can effectively remove more than 90 wt% of Cr(VI) from aqueous solution.

  6. A Facile Approach to Fabricate Water-soluble Au-Fe3O4 Nanoparticle for Liver Cancer Cells Imaging

    梁重时; 吴献荣; 谢叶归; 刘顺英

    2012-01-01

    Au-Fe3O4 nanoparticles were widely used as nanoplatforms for biologic applications through readily further functionalization. Dopamine (DA)-coated superparamagnetic iron oxide (SPIO) nanoparticles (DA@Fe3O4) have been successfully synthesized using a one-step process by modified coprecipitation method. Then 2--3 nm gold nanoparticles were easily conjugated to DA@Fe3O4 nanoparticles by the electrostatic force between gold nanoparti- cles and amino groups of dopamine to afford water-soluble Au-Fe3O4 hybrid nanoparticles. A detailed investigation by dynamic light scatting (DLS), transmission electron microscopy (TEM), fourier transform infrared (FT-IR) and X-ray diffraction (XRD) were performed in order to characterize the physicochemical properties of the hybrid nanoparticles. The hybrid nanoparticles were easily functionalized with a targeted small peptide A54 (AGKGTPSLETTP) and fluorescence probe fluorescein isothiocyanate (FITC) for liver cancer cell BEL-7402 imaging. This simple approach to prepare hybrid nanoparticles provides a facile nanoplatform for muti-functional derivations and may be extended to the immobilization of other metals or bimolecular on SPIO surface.

  7. Fabrication highly dispersed Fe3O4 nanoparticles on carbon nanotubes and its application as a mimetic enzyme to degrade Orange II.

    Deng, Jingheng; Wen, Xianghua; Li, Jiaxi

    2016-09-01

    Fe3O4 nanoparticles were grown in situ on carbon nanotubes (CNTs) by a solvothermal method. The Fe3O4/CNTs composites were characterised by the Brunauer-Emmett-Teller method and transmission electron microscopy. The results indicated that the Fe3O4 nanoparticles were uniformly deposited on CNTs, and the average diameter was approximately 7.0 nm. The Fe3O4/CNTs were applied as an enzyme mimetic to decompose Orange II, and the decomposing conditions were optimised. At 500 mg L(-1) of Fe3O4/CNTs in the presence of 15.0 mmol L(-1) of H2O2, at 30°C, it degraded 94.0% of Orange II (0.25 mmol L(-1), pH = 3.5), showing higher catalytic activity than pure Fe3O4 nanoparticles. The high activity was attributed to the uniform Fe3O4 nanoparticles growing on the side walls of the CNTs and the synergetic effect between Fe3O4 and CNTs. The Fe3O4/CNTs maintained their activity at temperatures as high as 65°C. The Fe3O4/CNTs presented high reusability and stability even after eight uses. These data proved that the Fe3O4/CNTs-catalysed degradation is a promising technique for wastewater treatment. Fe3O4 nanoparticles were grown in situ on carbon nanotubes (CNTs) by a solvothermal method. The Fe3O4/CNTs was applied as a mimetic enzyme to decompose Orange II. The Fe3O4/CNTs were collected after the reaction by applying an external magnetic field and can use repeatedly. PMID:26828855

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

    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

  9. Covalent Immobilization of Penicillin G Acylase onto Fe3O4@Chitosan Magnetic Nanoparticles.

    Ling, Xiao-Min; Wang, Xiang-Yu; Ma, Ping; Yang, Yi; Qin, Jie-Mei; Zhang, Xue-Jun; Zhang, Ye-Wang

    2016-05-28

    Penicillin G acylase (PGA) was immobilized on magnetic Fe3O4@chitosan nanoparticles through the Schiff base reaction. The immobilization conditions were optimized as follows: enzyme/support 8.8 mg/g, pH 6.0, time 40 min, and temperature 25°C. Under these conditions, a high immobilization efficiency of 75% and a protein loading of 6.2 mg/g-support were obtained. Broader working pH and higher thermostability were achieved by the immobilization. In addition, the immobilized PGA retained 75% initial activity after ten cycles. Kinetic parameters Vmax and Km of the free and immobilized PGAs were determined as 0.91 mmol/min and 0.53 mmol/min, and 0.68 mM and 1.19 mM, respectively. Synthesis of amoxicillin with the immobilized PGA was carried out in 40% ethylene glycol at 25°C and a conversion of 72% was obtained. These results showed that the immobilization of PGA onto magnetic chitosan nanoparticles is an efficient and simple way for preparation of stable PGA. PMID:26869599

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

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

  11. Sulphamic acid-functionalized magnetic Fe3O4 nanoparticles as recyclable catalyst for synthesis of imidazoles under microwave irradiation

    Javad Safari; Zohre Zarnegar

    2013-07-01

    Trisubstituted imidazoles have been synthesized in high yield in the presence of sulphamic acidfunctionalized magnetic Fe3O4 nanoparticles (SA-MNPs) as a novel solid acid catalyst under solvent-free classical heating conditions or using microwave irradiation. The heterogeneous catalyst could be recovered easily and reused many times without significant loss of catalytic activity.

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

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

    2015-01-01

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

  13. CaMoO4:TbatFe3O4 hybrid nanoparticles for luminescence and hyperthermia applications

    Parchur, A. K.; Kaurav, N.; Ansari, A. A.; Prasad, A. I.; Ningthoujam, R. S.; Rai, S. B.

    2013-02-01

    We have prepared CaMoO4:Tb@Fe3O4 hybrid nanoparticles by co-precipitation and polyol method. Their temperature kinetics for hyperthermia temperature ˜43 °C under different applied AC fields and the luminescence properties under UV-radiation are investigated. A strong green emission is observed due to the presence of Tb3+ ions.

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

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

  15. Passively Q-switched EDFL using Fe3O4-nanoparticle saturable absorber

    Bai, Xuekun; Xu, Luxi; Huang, Sujuan; Wang, Tingyun; Pu, Shengli; Zeng, Xianglong

    2015-01-01

    We experimentally demonstrate a passively Q-switched erbium-doped fiber laser (EDFL) operation by using a saturable absorber based on Fe3O4 nanoparticles (FONP) in magnetic fluid (MF). As a kind of transition metal oxide, the FONP has a large nonlinear optical response with a fast response time for saturable absorber. By depositing MF at the end of optical fiber ferrule, we fabricated a FONP-based saturable absorber, which enables a strong light-matter interaction owing to the confined transmitted optical field within the single mode fiber. Because of large third-order optical nonlinearities of FONP-based saturable absorber, large modulation depth of 8.2% and non saturable absorption of 56.6% are demonstrated. As a result, stable passively Q-switched EDFL pulses with maximum output pulse energy of 23.76 nJ, repetition rate of 33.3 kHz, and pulse width of 3.2 {\\mu}s are achieved when the input pump power is 110 mW at the wavelength of 980 nm. The laser features a low threshold pump power of ~15 mW.

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

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

    2015-06-01

    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 μM, 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.

  17. Fabrication of nanoporous nanocomposites entrapping Fe3O4 magnetic nanoparticles and oxidases for colorimetric biosensing.

    Kim, Moon Il; Shim, Jongmin; Li, Taihua; Lee, Jinwoo; Park, Hyun Gyu

    2011-09-12

    A nanostructured multicatalyst system consisting of Fe(3)O(4) magnetic nanoparticles (MNPs) as peroxidase mimetics and an oxidative enzyme entrapped in large-pore-sized mesoporous silica has been developed for convenient colorimetric detection of biologically important target molecules. The construction of the nanocomposites begins with the incorporation of MNPs on the walls of mesocellular silica pores by impregnating Fe(NO(3))(3)·9H(2)O, followed by the immobilization of oxidative enzymes. Glutaraldehyde crosslinking was employed to prevent enzymes leaching from the pores and led to over 20 wt% loading of the enzyme. The oxidase in the nanocomposite generates H(2)O(2) through its catalytic action for target molecules and subsequently activates MNPs to convert selected substrates into colored products. Using this strategy, two different biosensing systems were constructed employing glucose oxidase and cholesterol oxidase and their analytical capabilities were successfully verified by colorimetrically detecting the corresponding target molecules with excellent selectivity, sensitivity, reusability, and stability. Future potential applications of this technology range from biosensors to multicatalyst reactors. PMID:21837719

  18. Synthesis of Fe3O4/Pt Nanoparticles Decorated Carbon Nanotubes and Their Use as Magnetically Recyclable Catalysts

    Hongkun He

    2011-01-01

    Full Text Available We report a facile approach to prepare Fe3O4/Pt nanoparticles decorated carbon nanotubes (CNTs. The superparamagnetic Fe3O4 nanoparticles with average size of 4∼5 nm were loaded on the surfaces of carboxyl groups functionalized CNTs via a high-temperature solution-phase hydrolysis method from the raw material of FeCl3. The synthesis process of magnetic CNTs is green and readily scalable. The loading amounts of Fe3O4 nanopartilces and the magnetizations of the resulting magnetic CNTs show good tunability. The Pt nanopaticles with average size of 2.5 nm were deposited on the magnetic CNTs through a solution-based method. It is demonstrated that the Fe3O4/Pt nanoparticles decorated CNTs have high catalytic activity in the reduction reaction of 4-nitrophenol and can be readily recycled by a magnet and reused in the next reactions with high efficiencies for at least fifteen successive cycles. The novel CNTs-supported magnetically recyclable catalysts are promising in heterogeneous catalysis applications.

  19. Fe3O4 nanoparticles-wrapped carbon nanofibers as high-performance anode for lithium-ion battery

    One-dimensional hierarchical nanostructures composed of Fe3O4 nanoparticles and carbon nanofibers (CNFs) have been successfully synthesized through a facile solvothermal method followed by a simple thermal annealing treatment. X-ray diffraction and electron microscopy reveal that Fe3O4 nanoparticles with a size of 80–100 nm are uniformly dispersed on CNFs. The Fe3O4/CNFs nanocomposites show an enhanced reversible capacity and excellent rate performance as anode for Li-ion battery. The reversible capacity of the nanocomposites retains 684 mAh g−1 after 55 cycles at 100 mA g−1. Even when cycled at various rate (100, 200, 500, 1000, and 2000 mA g−1) for 50 cycles, the capacity can recover to 757 mAh g−1 at the current of 100 mA g−1. The enhanced electrochemical performances are attributed to the characteristics of interconnected one-dimensional nanostructures that provide three-dimensional networks for Li-ion diffusion and electron transfer, and can further accommodate the volumetric change of Fe3O4 nanoparticles during charge–discharge cycling

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

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

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

    Ishak Zamri

    2008-09-01

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

  2. Fe3O4/PS magnetic nanoparticles: Synthesis, characterization and their application as sorbents of oil from waste water

    In this work, Fe3O4/PS composites with a rough surface and different coating rates were successfully designed and synthesized by emulsion polymerization. We carried out some comparative experiments to compare magnetic properties and oil absorption properties of the nano-magnetic materials. It had been found that several prepared groups of magnetic nanocomposites have a core–shell structure and good coating rates. These nanoparticles combined with unsinked, highly hydrophobic and superoleophilic properties. The absorption capacity of Fe3O4/PS composites for organic solvents and the composites could absorb diesel oil up to 2.492 times of its own weight. It is more important that the oil could be readily removed from the surfaces of nanoparticles by a simple ultrasonic treatment whereas the nanocomposites particles still kept highly hydrophobic and superoleophilic characteristics. With a combination of simple synthesis process, low density, magnetic responsibility and excellent hydrophobicity, Fe3O4/PS nanocomposites as a promising absorbent have great potential in the application of spilled oil recovery and environmental protection. - Graphical abstract: In this article, Fe3O4/PS nanoparticles present a property called selective adsorption. When the nanocomposites are added into watchglass with a layer diesel oil dyed by Sudan red for clarity on a water surface, oil is quickly absorbed in few seconds and then keeps a balance of adsorption. Owing to the presence of Fe3O4 nanoparticles, the nanocomposites could be collected to the oil-polluted region by a magnet bar. The particles can dissolve in ethanol by ultrasonic washing. After that we can regenerate the magnetic composite materials through filtering, washing and drying, the process is showed in the following Figure. Adsorption and desorption of Fe3O4/PS nanoparticles. - Highlights: • We prepared Fe3O4/PS nanocomposites with different coating rates by emulsion polymerization method successfully. • Prepared

  3. Preparation and characterization of biofunctionalized chitosan/Fe3O4 magnetic nanoparticles for application in liver magnetic resonance imaging

    Song, Xiaoli; Luo, Xiadan; Zhang, Qingqing; Zhu, Aiping; Ji, Lijun; Yan, Caifeng

    2015-08-01

    Biofunctionalized chitosan@Fe3O4 nanoparticles are synthesized by combining Fe3O4 and CS chemically modified with PEG and lactobionic acid in one step. The biofunctionalized nanoparticles are characterized by TEM, X-ray, DLS, zeta-potential and magnetic measurements. The in vitro and in vivo behaviors of the biofunctionalized nanoparticles, especially, the cytotoxicity, the protein resistance, metabolism and iron toxicity are assessed. The functional groups, PEG enable the nanoparticles more biocompatible and the lactobionic acid groups enable liver targeting. The potential applications of the nanoparticles in liver magnetic resonance imaging are confirmed. The results demonstrated that the nanoparticles are suspension stability, non-cytotoxicity, non-tissue toxicity and sensitive in liver magnetic resonance imaging, representing potential tools for applications in the biomedical field.

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

    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.

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

    The photothermal effect of magnetite (Fe3O4) nanoparticles was characterized by photonic absorption in the near-infrared (NIR) region. Upon laser irradiation at 785 nm, the Fe3O4 nanoparticles generate localized hyperthermia in tumorous lesions, which is an effective strategy for cancer therapy; however, uncoated magnetite possesses an innate toxicity which can lead to drawbacks in the clinical setting. To reduce innate toxicity, a poly(acrylic acid) (PAA) coating on the nanoparticles was investigated in order to determine the alterations to stability and the degree of toxicity in an attempt to create a higher utility vector. It was found that the PAA coating significantly reduced the innate toxicity of the uncoated magnetite. Furthermore, the efficacy of PAA-coated magnetite nanoparticles (PAA-Fe3O4) was investigated for treating MDA-MB-231 (human mammary gland adenocarcinoma) cultures in viable concentration ranges (0.1–0.5 mg/ml). An appropriate PAA-Fe3O4 concentration range was then established for inducing significant cell death by hyperthermic ablation, but not through innate toxicity. - Highlights: • Uncoated magnetite NPs possess high innate toxicity in MDA-MB-231 cultures. • PAA coating significantly reduces innate toxicity and stabilizes magnetite NPs. • Thermal ablation begins at 0.2 mg/ml for PAA-Fe3O4 at 785 nm NIR laser, 38.5 kW/m2. • 38.5 kW/m2 does not significantly affect MDA-MB-231 viability in-vitro

  6. Research on Magnetic Fe3O4 Nano-Particles Applied in Water Treatment%用于水处理的磁性Fe3O4纳米微粒研究

    苏洁; 程文; 魏红; 何泽楠; 刘东; 左芬

    2012-01-01

    采用化学共沉淀法和水热法制备Fe3O4纳米磁性粒子及油酸包覆Fe3O4磁流体.通过实验确定最佳反应条件;用XRD分析Fe3O4粒子的晶体结构;用TEM观察磁流体样品的微观结构;用HPLC研究纳米粒子对左旋氧氟沙星溶液模拟废水超声降解的影响.结果表明产物为反尖晶石结构立方晶系的AB2O4型化合物,平均粒径小于15 nm;磁流体基本上为规则的球形,颗粒均匀,无团聚情况;制得的磁流体样品具有较好的流动性和超顺磁性;Fe3O4纳米粒子对左旋氧氟沙星具有一定的降解性能.%The Fe3O4 nano-particles and oil up on the Fe3O4 fluid are prepared by a chemical co-precipitation method and hydrothermal method. The optimum reaction conditions are determined through experiments. The crystal structure of Fe3O4 particles is analyzed via X-ray diffraction (XRD); the microstruc-ture of magnetic fluid sample is observed via transmission electron microscope (TEM); the effects of nano-particles on the degradation of levofloxacin solution imitating wastewater is investigated by high performance liquid chromatography( HPLC). The results show that the product is inverse spinel structure of the cubic crystal system-type compounds of AB204. The average particle size is less than 15 nm; magnetic fluid is regular spherical shape basically, particles uniformly and without agglomeration. Magnetic fluid samples are of good mobility and superparamagneticity; nano-size Fe3O4 can degrada levofloxacin to a certain extent.

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

    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

    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. Mapping the subcellular localization of Fe3O4@TiO2 nanoparticles by X-ray Fluorescence Microscopy

    The targeted delivery of Fe3O4@TiO2 nanoparticles to cancer cells is an important step in their development as nanomedicines. We have synthesized nanoparticles that can bind the Epidermal Growth Factor Receptor, a cell surface protein that is overexpressed in many epithelial type cancers. In order to study the subcellular distribution of these nanoparticles, we have utilized the sub-micron resolution of X-ray Fluorescence Microscopy to map the location of Fe3O4@TiO2 NPs and other trace metal elements within HeLa cervical cancer cells. Here we demonstrate how the higher resolution of the newly installed Bionanoprobe at the Advanced Photon Source at Argonne National Laboratory can greatly improve our ability to distinguish intracellular nanoparticles and their spatial relationship with subcellular compartments

  10. Preparation and Characterization of Fe3O4 Magnetic Nano-particles by 60Co γ-ray Irradiation

    Mingcheng YANG; Hongyan SONG; Chengshen ZHU; Suqin HE; Ya GAO

    2007-01-01

    By using a new method, 60C0 γ-ray irradiation, Fe3O4 magnetic nano-particles were successfully synthesized at room temperature under ambient pressure. The structure, morphology and magnetic properties of these nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM), respectively. The radiation formation mechanism was also discussed. The results show that the absorbed dose can greatly influence the structure, morphology and magnetic properties of the products. XRD and TEM studies show that the product prepared by γ-ray irradiation (10 kGy) is pure FesO4 phase and the mean diameter of these nano-particles is about 21 nm. The Fe3O4 nano-particles synthesized by γ-ray irradiation (10 kGy) are mainly in small cubic shape and the size uniformity of these particles is good.

  11. Regional selective construction of nano-Au on Fe3O4@SiO2@PEI nanoparticles by photoreduction

    Zhou, Ying; Ping, Tuo; Maitlo, Inamullah; Wang, Bowen; Yasir Akram, Muhammad; Nie, Jun; Zhu, Xiaoqun

    2016-05-01

    A magnetically separatable catalyst Fe3O4@SiO2@PEI@Au (gold) nanoparticle was successfully constructed by a novel regional selective photoreduction method. Based on the photolysis mechanism of a type II photoinitiator, through controlling the distribution of polyethylene imine (PEI), Au nanoparticles about 10 nm, which are only on the surface of the Fe3O4@SiO2@PEI nanoparticle, could be photoreduced due to the PEI acting as a coordinating agent, capping agent, and photoreducing agent simultaneously. The small size Au nanoparticles endow the catalyst with a high catalytic performance toward the reduction of 4-nitroaniline to 4-aminophenol by NaBH4. In addition, magnetic Fe3O4@SiO2@PEI@Au nanoparticles could easily be recovered and could be reused at least six times still keeping catalytic efficiency higher than 95%, which contributes to their high stability and magnetization. Furthermore, compared to another reported approach, this method showed great regional selectivity of reducing metal nanoparticles by controlling the distribution of the PEI. Taking advantage of the regional selectivity of the photoreducing method could also be used to fabricate other metal nanoparticles as catalysts for various reactions.

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

    Gang Yuan; Yongjie Yuan; Kan Xu; Qi Luo

    2014-01-01

    In accordance with the World Cancer Report, cancer has become the leading cause of mortality worldwide, and various therapeutic strategies have been developed at the same time. In the present study, biocompatible magnetic nanoparticles were designed and synthesized as high-performance photothermal agents for near-infrared light mediated cancer therapy in vitro. Via a facile one-pot solvothermal method, well-defined PEGylated magnetic nanoparticles (PEG–Fe3O4) were prepared with cheap inhesion...

  13. Effective decolorization and adsorption of contaminant from industrial dye effluents using spherical surfaced magnetic (Fe3O4) nanoparticles

    Suriyaprabha, R.; Khan, Samreen Heena; Pathak, Bhawana; Fulekar, M. H.

    2016-04-01

    Treatment of highly concentrated Industrial dye stuff effluents released in the environment is the major issue faced in the era of waste management as well as in water pollution. Though there is availability of conventional techniques in large numbers, there is a need of efficient and effective advance technologies. In account of that, Nanotechnology plays a prominent role to treat the heavy metals, organic and inorganic contaminants using smart materials in nano regime (1 -100 nm). Among these nanomaterials like Iron Oxide (Fe3O4, magnetic nanoparticle) is one of the most promising candidates to remove the heavy metals from the industrial effluent. Fe3O4 is the widely used smart material with magnetic property having high surface area; high surface to volume ratio provides more surface for the chemical reaction for the surface adsorption. Fe3O4 nanoparticles have been synthesized using sonochemical method using ultra frequency in aqueous solution under optimized conditions. The as-synthesized nanoparticle was analyzed using different characterization tool. The Transmission Electron microscope (TEM) images revealed 10-12 nm spherical shape nanoparticles; crystal phase and surface morphology was confirmed by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The functional group were identified by Fourier Transform-Infra Red Spectroscopy (FT-IR), revealed the bending and stretching vibrations associated with Iron Oxide nanoparticle. In present study, for the efficient removal of contaminants, different concentration (10-50 ppm) of dye stuff effluent has been prepared and subjected to adsorption and decolourization at definite time intervals with Fe3O4 nanoparticles. The concentration of Iron oxide and the time (45 mins) was kept fixed for the reaction whereas the concentration of dye stuff effluent was kept varying. It was found that the spherical shaped Fe3O4 proved to be the potential material for the adsorption of corresponding

  14. Study on Preparation and Tribological Performance of Stearic Acid Capped Fe3O4 Nanoparticle%硬脂酸修饰纳米Fe3O4的制备及摩擦学性能的研究

    杜润平; 柴多里

    2015-01-01

    通过微波水热法制备了表面修饰硬脂酸的纳米Fe3O4颗粒。运用红外光谱对其结构进行了分析,该添加剂具有较好的分散性与稳定性。经四球长磨实验表明,当表面修饰硬脂酸的纳米Fe3O4颗粒在液体石蜡油中的添加量为1.00%时,摩擦系数降至0.025,磨斑直径为0.47。%Stearic acid capped Fe3O4 nanoparticle was synthesized by using microwave hydrothermal method. The product was discussed on structure by IR. It has good dispersion and stability. A four-ball tribometer was employed to evaluate its tribological properties. The best tribological performance could be obtained with the coefficient of friction of 0.025,wear scar diameter of 0.47 mm,when the addition weight ratio of Stearic acid capped Fe3O4 nanoparticle in liquid paraffin is 1.00%.

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

    Graphical abstract: - Highlights: • Magnetic Fe3O4/C nanospheres were used in MSPE of BFRs and PCP from water samples. • The method shows merits of simpleness, reliableness and environmental friendliness. • The bonding between Fe3O4 and coated organic carbon has been demonstrated in Fe3O4/C. • The straight influences of synthesis conditions of Fe3O4/C on MSPE were investigated. • The extraction characteristics of Fe3O4/C nanoparticles were further elucidated. - Abstract: 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

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

    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

  17. Synthesis and characterization of core-shell type Fe3O4 nanoparticles in poly(organosilsesquioxane).

    Ervithayasuporn, Vuthichai; Kawakami, Yusuke

    2009-04-15

    The core-shell type Fe(3)O(4) nanoparticles in poly(organosilsesquioxane) (Fe(3)O(4)@OcTS) were prepared by one-pot synthesis using reverse micelle method. The as-prepared ferrofluid droplets with average size 4-15 nm were in situ encapsulated via polycondensation of molecularly self-assembled octenyltrimethoxysilane (OcTS). The dynamic light scattering and transmission electron microscopy investigations on coated magnetite nanoparticles revealed uniform size of spherical shape and having thin and transparent shells. These nanoparticles showed redispersibility in non-polar solvents without agglomerations due to coated by a layer of hydrophobic shells. The thermogravimetric analysis and infrared spectroscopy suggested the existence of core-shell type. X-ray diffraction confirmed magnetite cores. The superconducting quantum interference device (SQUID) showed that they exhibited superparamagnetic behavior at 300 K and ferromagnetic at 3 K. PMID:19150081

  18. Effect of Fe3O4 nanoparticles on space charge distribution in propylene carbonate under impulse voltage

    Addition of nanoparticles of the ferromagnetic material Fe3O4 can increase the positive impulse breakdown voltage of propylene carbonate by 11.65%. To further investigate the effect of ferromagnetic nanoparticles on the space charge distribution in the discharge process, the present work set up a Kerr electro-optic field mapping measurement system using an array photodetector to carry out time-continuous measurement of the electric field and space charge distribution in propylene carbonate before and after modification. Test results show that fast electrons can be captured by Fe3O4 nanoparticles and converted into relatively slow, negatively charged particles, inhibiting the generation and transportation of the space charge, especially the negative space charge

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

    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

  20. Formation and characterization of β-cyclodextrin (β-CD) - polyethyleneglycol (PEG) - polyethyleneimine (PEI) coated Fe3O4 nanoparticles for loading and releasing 5-Fluorouracil drug.

    Prabha, G; Raj, V

    2016-05-01

    In this work, β-cyclodextrin (β-CD) - polyethyleneglycol (PEG) - polyethyleneimine (PEI) coated iron oxide nanoparticles (Fe3O4-β-CD-PEG-PEI) were developed as drug carriers for drug delivery applications. The 5- Fluorouracil (5-FU) was chosen as model drug molecule. The developed nanoparticles (Fe3O4-β-CD-PEG-PEI) were characterized by various techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The average particles size range of 5-FU loaded Fe3O4-β-CD, Fe3O4-β-CD-PEG and Fe3O4-β-CD-PEG-PEI nanoparticles were from 151 to 300nm and zeta potential value of nanoparticles were from -43mV to -20mV as measured using Malvern Zetasizer. Finally, encapsulation efficiency (EE), loading capacity (LC) and in-vitro drug release performance of 5-FU drug loaded Fe3O4-β-CD, Fe3O4-β-CD-PEG and Fe3O4-β-CD-PEG-PEI nanoparticles was evaluated by UV-vis spectroscopy. In-vitro cytotoxicity tests investigated by MTT assay indicate that 5-FU loaded Fe3O4-β-CD-PEG-PEI nanoparticles were toxic to cancer cells and non-toxic to normal cells. The in-vitro release behavior of 5-FU from drug (5-FU) loaded Fe3O4-β-CD-PEG-PEI composite at different pH values and temperature was studied. It was found that 5-FU was released faster in pH 6.8 than in the acidic mediums (pH 1.2), and the released quantity was higher. Therefore, the newly prepared Fe3O4-β-CD-PEG-PEI carrier exhibits a promising potential capability for anticancer drug delivery in tumor therapy. PMID:27133054

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

    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

  2. Preparation and evaluation of the effect of Fe3 O4 @piroctone olamine magnetic nanoparticles on matrix metalloproteinase-2: a preliminary in vitro study.

    Shakibaie, Mojtaba; Haghiri, Mahboobe; Jafari, Mandana; Amirpour-Rostami, Sahar; Ameri, Alieh; Forootanfar, Hamid; Mehrabani, Mitra

    2014-01-01

    In the present study, Fe3 O4 magnetic nanoparticles were synthesized by the coprecipitation of Fe(2+) and Fe(3+) ions and used as a nanocarrier for the production of piroctone-olamine-loaded Fe3 O4 nanoparticles (Fe3 O4 @PO NPs). The nanocrystalline structure of the prepared iron oxide species was confirmed by the X-ray diffraction spectroscopy method. Particle size distribution analysis showed that the size of Fe3 O4 @PO NPs was in the range of 5-55 nm. The magnetization curve of Fe3 O4 @PO NPs (with saturation magnetization of 28.2 emu/g) confirmed its ferromagnetic property. Loading of PO on the surface of Fe3 O4 NPs qualitatively verified by Fourier transform infrared spectrum obtained from Fe3 O4 @PO NPs. Cytotoxicity studies on the human fibrosarcoma cell line (HT-1080) revealed higher inhibitory effect of Fe3 O4 @PO NPs (50% cell death [IC50 ] of 8.1 µg/mL) as compared with Fe3 O4 NPs (IC50 of 117.1 µg/mL) and PO (IC50 of 71.2 µg/mL) alone. In the case of human normal fibroblast (Hs68), the viability percentage was found to be 75% in the presence of Fe3 O4 @PO NPs (120 µg/mL). Gelatin zymography showed 17.2% and 34.6% inhibition of matrix metalloproteinase-2 (MMP-2) in the presence of Fe3 O4 @PO and PO, respectively, at the same concentration of 40 µg/mL, whereas Fe3 O4 NPs did not inhibit MMP-2 at any concentration. PMID:24716879

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

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

    2014-04-01

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

  4. Breast Tumor Targetable Fe3O4 Embedded Thermo-Responsive Nanoparticles for Radiofrequency Assisted Drug Delivery.

    Rejinold, N Sanoj; Thomas, Reju George; Muthiah, Muthunarayanan; Lee, Hwa Jeongong; Jeong, Yong Yeon; Park, In-kyu; Jayakumar, R

    2016-01-01

    Non-invasive radiofrequency (RF) frequency may be utilized as an energy source to activate thermo-responsive nanoparticles for the controlled local delivery of drugs to cancer cells. Herein, we demonstrate that 180 ± 20 nm sized curcumin encapsulated chitosan-graft-poly(N-vinyl caprolactam) nanoparticles containing iron oxide nanoparticles (Fe3O4-CRC-TRC-NPs) were selectively internalized in cancer cells in vivo. Using an RF treatment at 80 watts for 2 min, Fe3O4-CRC-TRC-NPs, dissipated heat energy of 42 degrees C, which is the lower critical solution temperature (LCST) of the chitosan-graft-poly(N-vinyl caprolactam), causing controlled curcumin release and apoptosis to cultured 4T1 breast cancer cells. Further, the tumor localization studies on orthotopic breast cancer model revealed that Fe3O4-CRC-TRC-NPs selectively accumulated at the primary tumor as confirmed by in vivo live imaging followed by ex vivo tissue imaging and HPLC studies. These initial results strongly support the development of RF assisted drug delivery from nanoparticles for improved tumor targeting for breast cancer treatment. PMID:27301171

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

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

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

    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.

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

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

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

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

    2014-01-01

    Colloidal Fe3O4 nanoparticles were synthesized using a gamma-radiolysis method in an aqueous solution containing iron chloride in presence of polyvinyl alcohol and isopropanol as colloidal stabilizer and hydroxyl radical scavenger, respectively. Gamma irradiation was carried out in a 60Co gamma source chamber at different absorbed doses. Increasing the radiation dose above a certain critical dose (100 kGy) leads to particle agglomeration enhancement, and this can influence the structure and c...

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

    Ma P

    2012-09-01

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

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

    Lai Yongchao

    2009-01-01

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

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

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

    2011-11-01

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

  12. SiO2 coated Fe3O4 magnetic nanoparticle dispersed multiwalled carbon nanotubes based amperometric glucose biosensor.

    Baby, Tessy Theres; Ramaprabhu, S

    2010-03-15

    A new type of amperometric glucose biosensor based on silicon dioxide coated magnetic nanoparticle decorated multiwalled carbon nanotubes (Fe(3)O(4)@SiO(2)/MWNTs) on a glassy carbon electrode (GCE) has been developed. MWNTs have been synthesized by catalytic chemical vapour decomposition (CCVD) of acetylene over rare earth (RE) based AB(3) alloy hydride catalyst. The as-grown MWNTs have been purified and further functionlized. Functionalized MWNTs have been decorated with magnetic Fe(3)O(4) nanoparticles which have been uniformly coated with biocompatible SiO(2) using a simple chemical reduction method. The characterization of magnetic nanoparticle modified MWNTs have been done by X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), energy dispersive X-ray analysis (EDX) and UV-vis spectroscopy. Amperometric biosensor has been fabricated by the deposition of glucose oxidase (GOD) over Nafion-solubilized Fe(3)O(4)@SiO(2)/MWNTs electrode. The resultant bioelectrode retains its biocatalytic activity and offers fast and sensitive glucose quantification. The performance of the biosensor has been studied using cyclic voltammetry and amperometry and the results have been discussed. The fabricated glucose biosensor exhibits a linear response from 1 microM to 30 mM with an excellent detection limit of 800 nM indicating the potential applications in food industries. PMID:20152447

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

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

  14. Preparation and imaging study of tumor-targeting MRI contrast agent based on Fe3O4 nanoparticles

    The detection and diagnosis of early hypoxic tumor is the key for successful cancer therapy, which remains a challenge for radiologists because contrast agents could hardly reach it. Herein, a tumor-targeting MRI contrast agent was prepared by conjugating the small-molecule inhibitor of carbonic anhydrase (CA IX) that is overexpressed in hypoxic tumor, mafenide, onto the surface of Fe3O4 magnetic nanoparticles (MNPs) to improve the sensitivity of MRI for early tumor diagnosis. The tumor-targeting MNP (Fe3O4-SO2NH2) showed enhanced MRI contrasting performance both in vitro and in vivo in comparison with the non-targeting control, which made it a promising contrast agent for the detection and diagnosis of early hypoxic tumor. (author)

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

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

  16. Fe3O4/PS magnetic nanoparticles: Synthesis, characterization and their application as sorbents of oil from waste water

    Yu, Liuhua; Hao, Gazi; Gu, Junjun; Zhou, Shuai; Zhang, Ning; Jiang, Wei

    2015-11-01

    In this work, Fe3O4/PS composites with a rough surface and different coating rates were successfully designed and synthesized by emulsion polymerization. We carried out some comparative experiments to compare magnetic properties and oil absorption properties of the nano-magnetic materials. It had been found that several prepared groups of magnetic nanocomposites have a core-shell structure and good coating rates. These nanoparticles combined with unsinked, highly hydrophobic and superoleophilic properties. The absorption capacity of Fe3O4/PS composites for organic solvents and the composites could absorb diesel oil up to 2.492 times of its own weight. It is more important that the oil could be readily removed from the surfaces of nanoparticles by a simple ultrasonic treatment whereas the nanocomposites particles still kept highly hydrophobic and superoleophilic characteristics. With a combination of simple synthesis process, low density, magnetic responsibility and excellent hydrophobicity, Fe3O4/PS nanocomposites as a promising absorbent have great potential in the application of spilled oil recovery and environmental protection.

  17. Magnetic adsorbent of Fe3O4@SiO2 core-shell nanoparticles modified with thiol group for chloroauric ion adsorption

    Roto, Roto; Yusran, Yusran; Kuncaka, Agus

    2016-07-01

    The magnetic adsorbent of Fe3O4@SiO2 core-shell nanoparticles modified with thiol group was synthesized for chloroauric ([AuCl4]-) adsorption. The Fe3O4 nanoparticles were prepared by co-precipitation method under mechanical stirring and coated with SiO2 by acid hydrolysis of Na2SiO3 under N2 purging. The coating of Fe3O4 nanoparticles with SiO2 prevents particles' agglomeration by forming Fe3O4 Fe3O4 Fe3O4@SiO2 core-shell and avoids dissolution of the Fe3O4 core in the acidic medium. The coated Fe3O4 particle was modified with a thiol group using 3-mercaptopropyltrimethoxysilane via silanization reaction. The results suggest that SiO2-coated Fe3O4 particles have a size of 10-20 nm. The FTIR and EDX data indicate that the thiol groups are successfully attached to the surface of the nanoparticles. The [AuCl4]- ion adsorption by the Fe3O4@SiO2 core-shell nanoparticles followed Langmuir isotherm model with a maximum adsorption capacity of 115 mg/g and free energy (ΔG°) of 24.8 kJ/mol. The thiourea solution can be used to desorb most of the adsorbed [AuCl4]- ion. The adsorption using magnetic compounds provides easy access to the separation for both preparation and recovery.

  18. Magnetic field induced ferroelectric and dielectric properties in Pb(Zr0.5Ti0.5)O3 films containing Fe3O4 nanoparticles

    About 1.05 μm-thick Pb(Zr0.5Ti0.5)O3 (PZT) films containing Fe3O4 nanoparticles were deposited on LaNiO3-coated silicon substrates through a sol-gel technique. Fe3O4 nanoparticles were effectively dispersed into PZT solution under the involvement of polyvinylpyrrolidone. X-ray diffraction confirmed the coexistence of PZT and Fe3O4 phases without other impurity phases. Scanning electron microscope revealed that the thick composite films possess well-defined and crack-free microstructure. The composite films exhibit good ferroelectric and ferromagnetic properties at room temperature. An obvious magnetodielectric effect has been demonstrated in the Pb(Zr0.5Ti0.5)O3/Fe3O4 composite films. Magnetic field induced change in ferroelectric polarization loop may support the possible magnetoelectric coupling between PZT and Fe3O4 phases.

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

    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)

  20. Preparation of the chitosan grafted poly (quaternary ammonium)/Fe3O4 nanoparticles and its adsorption performance for food yellow 3.

    Yu, Chen; Geng, Jianqiang; Zhuang, Yunxia; Zhao, Jian; Chu, Liqiu; Luo, Xiaoxuan; Zhao, Ying; Guo, Yanwen

    2016-11-01

    Chitosan and its derivatives can be used to modify magnetic materials to promote the adsorption properties of the magnetic materials and avoid the weakness of chitosan and its derivatives. In the present study, chitosan grafted poly(trimethyl allyl ammonium chloride) (CTS-g-PTMAAC) was prepared by graft copolymerization; then it was coated on the surfaces of the sodium citrate coated Fe3O4 nanoparticles (SC-Fe3O4) to prepare a novel composite CTS-g-PTMAAC/SC-Fe3O4 magnetic nanoparticles, with which possesses abundant surface positive charges. The structure and properties of the CTS-g-PTMAAC/SC-Fe3O4 composite magnetic nanoparticles were characterized by FTIR, TEM, VSM, and zeta potential. The dye adsorption characteristics of the CTS-g-PTMAAC/SC-Fe3O4 nanoparticles were determined using the food yellow 3 aqueous solutions as a model food effluent. Effect of pH of the dye solution on the adsorption of food yellow 3 was determined and compared with N-2-hydroxylpropyl trimethyl ammonium chloride chitosan coated sodium citrate-Fe3O4 (CTS-g-HTCC/SC-Fe3O4) composite magnetic nanoparticles. The adsorption kinetics, adsorption isotherms, adsorption thermodynamics, and desorption and reusability of the magnetic nanoparticles were investigated. PMID:27516279

  1. Synthesis and application of bilayer-surfactant-enveloped Fe3O4 nanoparticles: water-based bilayer-surfactant-enveloped ferrofluids

    Chen, Bai-yi; Qiu, Jian-hui; Feng, Hui-xia

    2016-02-01

    Superparamagnetic carbon-coated Fe3O4 nanoparticles with high magnetization (85 emu·g-1) and high crystallinity were synthesized using polyethylene glycol-4000 (PEG (4000)) as a carbon source. Fe3O4 water-based bilayer-surfactant-enveloped ferrofluids were subsequently prepared using sodium oleate and PEG (4000) as dispersants. Analyses using X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy indicate that the Fe3O4 nanoparticles with a bilayer surfactant coating retain the inverse spinel-type structure and are successfully coated with sodium oleate and PEG (4000). Transmission electron microscopy, vibrating sample magnetometry, and particle-size analysis results indicate that the coated Fe3O4 nanoparticles also retain the good saturation magnetization of Fe3O4 (79.6 emu·g-1) and that the particle size of the bilayer-surfactant-enveloped Fe3O4 nanoparticles is 42.97 nm, which is substantially smaller than that of the unmodified Fe3O4 nanoparticles (486.2 nm). UV-vis and zeta-potential analyses reveal that the ferrofluids does not agglomerate for 120 h at a concentration of 4 g·L-1, which indicates that the ferrofluids are highly stable.

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

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

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

    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. - Highlights: • An effective approach to graft CuPc containing flexible chains on Fe. • Effect on the mechanical, thermal and interfacial properties were investigated. • The dispersion state was characterized using parallel-plate rheometry. • The mechanism of interfacial compatibility was clarified

  4. Anchoring Fe3O4 nanoparticles on three-dimensional carbon nanofibers toward flexible high-performance anodes for lithium-ion batteries

    Wan, Yizao; Yang, Zhiwei; Xiong, Guangyao; Guo, Ruisong; Liu, Ze; Luo, Honglin

    2015-10-01

    There is growing interest in flexible, cost-effective, and binder-free energy storage devices to meet the special needs of modern electronic systems. Herein we report a general, scalable, eco-friendly, and cost-effective approach for the fabrication of nano-Fe3O4-anchored three-dimensional (3D) carbon nanofiber (CNFs) aerogels (Fe3O4@BC-CNFs). The preparation processes include the anchoring of Fe2O3 nanoparticles on bacterial cellulose (BC) nanofibers with intrinsic 3D network structure and subsequent carbonization at different temperatures. The aerogel carbonized at 600 °C (Fe3O4@BC-CNFs-600) is highly flexible and was directly used as working electrodes in lithium-ion batteries without metal current collectors, conducting additives, or binders. The Fe3O4@BC-CNFs-600 demonstrates greatly improved electrochemical performance in comparison to the bare Fe3O4 nanoparticles. In addition to its excellent flexibility, a stable capacity of 755 mAh g-1 for up to 80 cycles is also higher than most of carbon-Fe3O4 hybrids. The high reversible capacity and excellent rate capability are attributed to its 3D porous network structure with well-dispersed Fe3O4 nanoparticles on the surfaces of CNFs.

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

    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.

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

    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.

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

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

    2014-04-01

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

  8. Bio-inspired green synthesis of Fe3O4 magnetic nanoparticles using watermelon rinds and their catalytic activity

    Prasad, Ch.; Gangadhara, S.; Venkateswarlu, P.

    2016-08-01

    Novel and bio-inspired magnetic nanoparticles were synthesized using watermelon rinds (WR) which are nontoxic and biodegradable. Watermelon rind extract was used as a solvent and capping and reducing agent in the synthesis. The Fe3o4 MNPs were characterized by using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer techniques (VSM). XRD studies revealed a high degree of crystalline and monophasic Fe nanoparticles of face-centered cubic stricture. FTIR analysis proved that particles are reduced and stabilized in solution by the capping agent that is likely to be proteins secreted by the biomass. The present process in an excellent candidate for the synthesis of iron nanoparticles that is simple, easy to execute, pollutant free and inexpensive. A practical and convenient method for the synthesis of highly stable and small-sized iron nanoparticles with a narrow distribution from 2 to 20 nm is reported. Also, the MNPs present in higher saturation magnetization (Ms) of 14.2 emu/g demonstrate tremendous magnetic response behavior. However, the synthesized iron nanoparticles were used as a catalyst for the preparation of biologically interesting 2-oxo-1,2,3,4-tetrahydropyrimidine derivatives in high yields. These results exhibited that the synthesized Fe3O4 MNPs could be used as a catalyst in organic synthesis.

  9. Tailoring mechanical and antibacterial properties of chitosan/gelatin nanofiber membranes with Fe3O4 nanoparticles for potential wound dressing application

    Cai, Ning; Li, Chao; Han, Chao; Luo, Xiaogang; Shen, Liang; Xue, Yanan; Yu, Faquan

    2016-04-01

    In this work, magnetic Fe3O4 nanoparticles (NPs) were utilized to improve the mechanical and antibacterial properties of chitosan (CS)/gelatin (GE) composite nanofiber membranes. Homogeneous Fe3O4/CS/GE nanofibers were electrospun successfully. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirmed the presence of well-dispersed Fe3O4 NPs in the composite nanofibers. Fourier transform infrared spectroscopy (FTIR) spectra revealed the effective interactions of Fe3O4 NPs to the composite matrix through hydrogen bonding. The improvement on the thermal stability of the Fe3O4/CS/GE was observed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA), which is tightly correlated to strong filler-matrix adhesion. The incorporation of Fe3O4 NPs resulted in a substantial enhancement of mechanical properties. The optimum mechanical performance was demonstrated on 1 wt% Fe3O4/CS/GE nanofiber membranes, achieving 155% augment of Young's modulus, 128% increase of tensile strength, and 100% boost of toughness from CS/GE. The excellent mechanical enhancement can be explained by the effective dispersion of fillers and the filler-matrix interactions, which ensures the efficient load transfer from CS/GE matrix to Fe3O4 nanofillers. Moreover, zones of inhibition for Escherichia coli and Staphylococcus aureus expanded markedly with the supplement of Fe3O4 NPs. In all, nanofiber membranes made of Fe3O4/CS/GE composite with tailored mechanical and antibacterial properties appear a promising wound dressing material.

  10. Sol-gel synthesis of 8 nm magnetite (Fe 3O 4) nanoparticles and their magnetic properties

    Lemine, O. M.

    2012-10-01

    Magnetite (Fe 3O 4) nanoparticles were successfully synthesized by a sol-gel method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDAX), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) and Mössbauer spectrometry. XRD and Mössbauer measurements indicate that the obtained nanoparticles are single phase. TEM analysis shows the presence of spherical nanoparticles with homogeneous size distribution of about 8 nm. Room temperature ferromagnetics behavior was confirmed by SQUID measurements. The mechanism of nanoparticles formation and the comparison with recent results are discussed. Finally, the synthesized nanoparticles present a potential candidate for hyperthermia application given their saturation magnetization. © 2012 Elsevier Ltd. All rights reserved.

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

    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.

  12. Influence of Fe3O4 Nanoparticles in Hydroxyapatite Scaffolds on Proliferation of Primary Human Fibroblast Cells

    Maleki-Ghaleh, H.; Aghaie, E.; Nadernezhad, A.; Zargarzadeh, M.; Khakzad, A.; Shakeri, M. S.; Beygi Khosrowshahi, Y.; Siadati, M. H.

    2016-05-01

    Modern techniques for expanding stem cells play a substantial role in tissue engineering: the raw material that facilitates regeneration of damaged tissues and treats diseases. The environmental conditions and bioprocessing methods are the primary determinants of the rate of cultured stem cell proliferation. Bioceramic scaffolds made of calcium phosphate are effective substrates for optimal cell proliferation. The present study investigates the effects of two bioceramic scaffolds on proliferating cells in culture media. One scaffold was made of hydroxyapatite and the other was a mixture of hydroxyapatite and ferromagnetic material (Fe3O4 nanoparticles). Disk-shaped (10 mm × 2 mm) samples of the two scaffolds were prepared. Primary human fibroblast proliferation was 1.8- and 2.5-fold faster, respectively, when cultured in the presence of hydroxyapatite or ferrous nanoparticle/hydroxyapatite mixtures. Optical microscopy images revealed that the increased proliferation was due to enhanced cell-cell contact. The presence of magnetic Fe3O4 nanoparticles in the ceramic scaffolds significantly increased cell proliferation compared to hydroxyapatite scaffolds and tissue culture polystyrene.

  13. Influence of Fe3O4 Nanoparticles in Hydroxyapatite Scaffolds on Proliferation of Primary Human Fibroblast Cells

    Maleki-Ghaleh, H.; Aghaie, E.; Nadernezhad, A.; Zargarzadeh, M.; Khakzad, A.; Shakeri, M. S.; Beygi Khosrowshahi, Y.; Siadati, M. H.

    2016-06-01

    Modern techniques for expanding stem cells play a substantial role in tissue engineering: the raw material that facilitates regeneration of damaged tissues and treats diseases. The environmental conditions and bioprocessing methods are the primary determinants of the rate of cultured stem cell proliferation. Bioceramic scaffolds made of calcium phosphate are effective substrates for optimal cell proliferation. The present study investigates the effects of two bioceramic scaffolds on proliferating cells in culture media. One scaffold was made of hydroxyapatite and the other was a mixture of hydroxyapatite and ferromagnetic material (Fe3O4 nanoparticles). Disk-shaped (10 mm × 2 mm) samples of the two scaffolds were prepared. Primary human fibroblast proliferation was 1.8- and 2.5-fold faster, respectively, when cultured in the presence of hydroxyapatite or ferrous nanoparticle/hydroxyapatite mixtures. Optical microscopy images revealed that the increased proliferation was due to enhanced cell-cell contact. The presence of magnetic Fe3O4 nanoparticles in the ceramic scaffolds significantly increased cell proliferation compared to hydroxyapatite scaffolds and tissue culture polystyrene.

  14. Intensification of levofloxacin sono-degradation in a US/H2O2 system with Fe3O4 magnetic nanoparticles

    Hong Wei; Da Hu; Jie Su; Kebin Li

    2015-01-01

    Fe3O4 magnetic nanoparticles (MNPs) were synthesised, characterised, and used as a peroxidase mimetic to ac-celerate levofloxacin sono-degradation in an ultrasound (US)/H2O2 system. The Fe3O4 MNPs were in nanometre scale with an average diameter of approximately 12 to 18 nm. The introduction of Fe3O4 MNPs increased levofloxacin sono-degradation in the US/H2O2 system. Experimental parameters, such as Fe3O4 MNP dose, initial solution pH, and H2O2 concentration, were investigated by a one-factor-at-a-time approach. The results showed that Fe3O4 MNPs enhanced levofloxacin removal in the pH range from 4.0 to 9.0. Levofloxacin removal ratio in-creased with Fe3O4 MNP dose up to 1.0 g·L−1 and with H2O2 concentration until reaching the maximum. More-over, three main intermediate compounds were identified by HPLC with electrospray ionisation tandem mass spectrometry, and a possible degradation pathway was proposed. This study suggests that combination of H2O2, Fe3O4 MNPs and US is a good way to improve the degradation efficiency of antibiotics.

  15. Development of citrate-stabilized Fe3O4 nanoparticles: Conjugation and release of doxorubicin for therapeutic applications

    We demonstrate a single-step facile approach for the fabrication of citric acid functionalized (citrate-stabilized) Fe3O4 aqueous colloidal magnetic nanoparticles (CA-MNP) of size 8-10 nm using soft chemical route. The surface functionalization of Fe3O4 nanoparticles with citric acid was evident from infrared spectroscopy, thermal and elemental analyses, and zeta-potential measurements. The drug-loading efficiency of CA-MNP was investigated using doxorubicin hydrochloride (DOX) as a model drug to evaluate their potential as a carrier system. The quenching of fluorescence intensity and decrease in surface charge of drug loaded CA-MNP strongly suggest the interaction/attachment of drug molecules with CA-MNP. More specifically, the present investigation discusses a method for entrapping positively charged drugs onto the surface of negatively charged CA-MNP through electrostatic interactions and suggests that bound drug molecules will be released in appreciable amounts in the mild acidic environments of the tumors. Furthermore, the aqueous colloidal stability, optimal magnetization, good specific absorption rate (under external AC magnetic field) and cytocompatibility with cells suggested that CA-MNP is appropriate candidate for biomedical applications.

  16. Quantitative two-dimensional strain mapping of small core-shell FePt@Fe3O4 nanoparticles

    Monteforte, Marianne; Kobayashi, Shoko; Tung, Le D.; Higashimine, Koichi; Mott, Derrick M.; Maenosono, Shinya; Thanh, Nguyen T. K.; Robinson, Ian K.

    2016-03-01

    We report a facile one-pot chemical synthesis of colloidal FePt@Fe3O4 core-shell nanoparticles (NPs) with an average diameter of 8.7 ± 0.4 nm and determine their compositional morphology, microstructure, two-dimensional strain, and magnetic hysteresis. Using various state-of-the-art analytical transmission electron microscopy (TEM) characterization techniques—including high resolution TEM imaging, TEM tomography, scanning TEM-high angle annular dark field imaging, and scanning TEM-energy dispersive x-ray spectroscopy elemental mapping—we gain a comprehensive understanding of the chemical and physical properties of FePt@Fe3O4 NPs. Additional analysis using x-ray photoelectron spectroscopy, x-ray diffraction, and superconducting quantum interference device magnetometry distinguishes the oxide phase and determines the magnetic properties. The geometric phase analysis method is effective in revealing interfacial strain at the core-shell interface. This is of fundamental interest for strain engineering of nanoparticles for desirable applications.

  17. Fe3 O4 nanoparticle redox system modulation via cell-cycle progression and gene expression in human mesenchymal stem cells.

    Periasamy, Vaiyapuri S; Athinarayanan, Jegan; Alhazmi, Mohammad; Alatiah, Khalid A; Alshatwi, Ali A

    2016-08-01

    The use of engineered nanoparticles (NPs) across multiple fields and applications has rapidly increased over the last decade owing to their unusual properties. However, there is an increased need in understanding their toxicological effect on human health. Particularly, iron oxide (Fe3 O4 ) have been used in various sectors, including biomedical, food, and agriculture, but the current understanding of their impact on human health is inadequate. In this investigation, we assessed the toxic effect of Fe3 O4 NPs on human mesenchymal stem cells (hMSCs) adopting cell viability, cellular morphological changes, mitochondrial transmembrane potential, and cell-cycle progression assessment methodologies. Furthermore, the expression of oxidative stress, cell death, and cell-cycle regulatory genes was assessed using quantitative polymerase chain reaction. The Fe3 O4 NPs induced cytotoxicity and nuclear morphological changes in hMSCs by dose and time exposure. Cell-cycle analysis indicated that Fe3 O4 NPs altered the cell-cycle progression through a decrease in the proportion of cells in the G0 -G1 phase. The hMSC mitochondrial membrane potential loss increased with an increase in the concentration of Fe3 O4 NPs exposure. The observed expression levels of the CYP1A, TNF3, TNFSF10, E2F1, and CCNC genes were significantly upregulated in hMSCs in response to Fe3 O4 NPs exposure. Our findings suggest that Fe3 O4 NPs caused metabolic stress through altered cell cycle, oxidative stress, and cell death regulatory gene expression in hMSCs. The results of this investigation revealed that Fe3 O4 NPs exhibited moderate toxicity on hMSCs and that Fe3 O4 NPs may have biomedical applications at low concentrations. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 901-912, 2016. PMID:25532727

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

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

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

    2013-05-21

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

  20. Viscosity of low volume concentrations of magnetic Fe3O4 nanoparticles dispersed in ethylene glycol and water mixture

    Syam Sundar, L.; Venkata Ramana, E.; Singh, M. K.; De Sousa, A. C. M.

    2012-12-01

    This Letter reveals an experimental investigation of rheological properties of Fe3O4 nanoparticles dispersed in 60:40%, 40:60% and 20:80% (by weight) ethylene glycol and water mixture. Magnetic nanoparticles were synthesized by chemical coprecipitation method. The experiments were carried out in the particle volume concentration range from 0.0% to 1.0% and temperature range from 0 °C to 50 °C. Viscosity of nanofluid increases with increase of volume concentration and decreases with increase of temperature. The results indicate that the 60:40% EG/W based nanofluid is 2.94 times more viscous compared to the other base fluids. Einstein model was under predicting the experimental viscosity for all the base fluids.

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

    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, β increase 102 and 101 times, respectively, in homeotropic alignment samples and the sign of these parameters is changed rather than homogeneous ones

  2. Preparation of Chitosan modified Iron Oxide Nanoparticles%壳聚糖/Fe3O4复合纳米颗粒的制备

    石浩明; 张树彪; 陈会英; 赵轶男; 崔韶晖; 那立艳; 华瑞年

    2012-01-01

    以柠檬酸为改性剂,制备水基Fe3O4磁性纳米粒子,基于静电自组装作用,使壳聚糖分子在水溶液中包覆Fe3O4纳米晶粒,获得壳聚糖/Fe3O4复合纳米颗粒液溶胶。扫描电子显微镜(SEM)分析结果表明,复合纳米颗粒平均粒径为49.0nm,标准差为11.0nm。X射线衍射(XRD)和红外光谱(FT-IR)分析结果表明,复合纳米颗粒由壳聚糖分子和Fe3O4晶体粒子构成。%The magnetic fluid was prepared by modifying the surface of F% 04 nanoparticles with citric acid. These Fe3O4 nanoparticles encapsulated by chitosan molecules through electrostatic force could be readily dispersed in aqueous solution. It was found in the SEM image that the aver- age diameter of nanocomplex was 49.0 nm, standard deviation was 11.0 nmo The particles prepared from chitosan and Fe3O4 were characterized by XRD and FF- IR nanocomplex analysis.

  3. Nanosized Fe3O4 an efficient PCR yield enhancer-Comparative study with Au, Ag nanoparticles.

    Kambli, Priyanka; Kelkar-Mane, Varsha

    2016-05-01

    Nanomaterials-assisted PCR is a promising field of nanobiotechnology that amalgamates nanomaterials into the conventional PCR system to achieve better amplification of desired product. With literature documenting the variable effects of these nanomaterials on the PCR yield and amplification; it was thought worthwhile to compare the PCR enhancing efficiency of three transition metal nanoparticles in form of stable colloidal suspensions at varying concentrations.The nanoparticles(NPs) of silver, gold and magnetite were chemically synthesized by reducing their respective salts and characterized using UV-vis spectroscopy. Their morphology was assessed using nanoparticle tracking system and AFM. The effect of these nanofluids on amplification of 800 bp prokaryotic DNA template with 30% GC content was studied using conventional thermal cycler. The reaction kinetics for all the three nanofluids yielded a Gaussian curve of amplification with varying concentrations. The ammonium salt of oleic acid coated magnetite (Fe3O4) nanoparticles at a concentration of 0.72 × 10(-2)nM and average size of 33 nm demonstrated highest amplification efficiency of 190% as compared to the citrate stabilized AgNP-25 nm (45%) and AuNP-15.19 nm (134%) using a conventional PCR system. The major reasons that allow Fe3O4 NPs outperform the other 2 transition metal NP's seem to be attributed to its heat conduction property as well as effective adsorption of PCR components onto the ammonium salt of oleic acid coated magnetite nanofluids. The data from our study offers valuable information for the application of ferrofluids as economically, efficient and effective alternative for nanomaterial-assisted PCR yield enhancers. PMID:26896662

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

    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

  5. Preparation and characterization of bifunctional dendrimer modified Fe3O4/CdTe nanoparticles with both luminescent and superparamagnetic properties

    Highlights: • The fluorescent superparamagnetic dendrimeric Fe3O4/CdTe nanoparticles are synthesized in this paper. • The synthesized nanocomposites maintain excellent magnetic properties. • The synthesized nanocomposites maintain highly luminescent markers with narrow emission bands. - Abstract: Magnetic nanoparticles Fe3O4 were prepared by hydrothermal coprecipitation of ferric and ferrous ions using NaOH. The surface modification of Fe3O4 nanoparticle by dendrimers has rendered the nanoparticle surface with enriched amine groups which facilitated the adsorption and conjugation of thioglycolic acid (TGA) modified CdTe quantum dots to form a stable hybrid nanostructure. Three generations (first generation: G0F, second generation: G1F, third generation: G3F) of bifunctional dendrimeric Fe3O4/CdTe nanoparticles were successfully prepared using this technique and characterized by microscopy. The optical and magnetic properties of the dendrimeric Fe3O4/CdTe nanoparticle were also investigated. The microscopic study reveals 3 different sizes for 3 generations, 16 nm (G0F), 31 nm (G1F) and 47 nm (G3F). Among three generations of nanoparticles, the G1F has the best optical property with a luminescent quantum yield of 25.6% and the G0F has the best magnetic property with a saturation magnetization of 19.3 emμ/g

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

    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.

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

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

    2014-09-01

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

  8. In situ loading of gold nanoparticles on Fe3O4@SiO2 magnetic nanocomposites and their high catalytic activity

    Zheng, Jinmin; Dong, Yalei; Wang, Weifeng; Ma, Yanhua; Hu, Jing; Chen, Xiaojiao; Chen, Xingguo

    2013-05-01

    In this work, a facile approach was successfully developed for in situ catalyzing Au nanoparticles loaded on Fe3O4@SiO2 magnetic nanospheres via Sn2+ linkage and reduction. After the Fe3O4@SiO2 MNPs were first prepared via a sol-gel process, only one step was needed to synthesize the Fe3O4@SiO2-Au magnetic nanocomposites (Fe3O4@SiO2-Au MNCs), so that both the synthesis step and the reaction cost were remarkably decreased. Significantly, the as-synthesized Fe3O4@SiO2-Au MNCs showed high performance in the catalytic reduction of 4-nitrophenol to 4-aminophenol and could be reused for several cycles with convenient magnetic separability. This approach provided a useful platform based on Fe3O4@SiO2 MNPs for the fabrication of Au or other noble metal magnetic nanocatalysts, which would be very useful in various catalytic reductions.

  9. Partial slip effect in flow of magnetite-Fe3O4 nanoparticles between rotating stretchable disks

    Hayat, Tasawar; Qayyum, Sumaira; Imtiaz, Maria; Alzahrani, Faris; Alsaedi, Ahmed

    2016-09-01

    This paper addresses the flow of magnetic nanofluid (ferrofluid) between two parallel rotating stretchable disks with different rotating and stretching velocities. Water based fluid comprising magnetite-Fe3O4 nanoparticles is addressed. Velocity slip and temperature jump at solid-fluid interface are also taken into account. Appropriate transformations reduce the nonlinear partial differential system to ordinary differential system. Convergent series solutions are obtained. Effects of various pertinent parameters on the velocity and temperature profiles are shown and evaluated. Computations for skin friction coefficient and Nusselt number are presented and examined for the influence of involved parameters. It is noted that tangential velocity of fluid decreases for larger velocity slip parameter. Fluid temperature also reduces for increasing value of thermal slip parameter. Surface drag force and heat transfer rate at lower disk are enhanced when magnetic field strength is increased.

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

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

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

    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

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

    Cai Jingting

    2011-02-01

    Full Text Available Cai Jingting1,2, Liu Huining1, Zhang Yi11Department of Obstetrics and Gynecology, Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 2Department of Gynecological Oncology, Hunan Tumor Hospital, Changsha, Hunan, People’s Republic of ChinaObjective: To evaluate the feasibility of using magnetic iron oxide (Fe3O4-dextran-anti-β-human chorionic gonadotropin (HCG nanoparticles as a gene vector for cellular transfections.Study design: Fe3O4-dextran-anti-β-HCG nanoparticles were synthesized by chemical coprecipitation. The configuration, diameter, and iron content of the nanoparticles were detected by transmission electron microscopy (TEM, light scatter, and atomic absorption spectrophotometry. A3-(4,5-dimethylthiahiazo(-z-y1-3,5-di-phenytetrazoliumromide assay was used to evaluate the cytotoxicity of Fe3O4-dextran-anti-β-HCG nanoparticles. Enzyme-linked immunosorbent assay and indirect immunofluorescence were used to evaluate immunoreactivity. The efficiency of absorbing DNA and resisting deoxyribonuclease I (DNase I digestion when bound to Fe3O4-dextran-anti-β-HCG nanoparticles was examined by agarose gel electrophoresis. The ability of Fe3O4-dextran-anti-β-HCG nanoparticles to absorb heparanase antisense oligodeoxynucleotides (AS-ODN nanoparticles in different cell lines was evaluated by flow cytometry. The tissue distribution of heparanase AS-ODN magnetic nanoparticles in choriocarcinoma tumors transplanted in nude mice was detected by atomic absorption spectrophotometry.Results: TEM demonstrated that the shape of nanoparticles is irregular. Light scatter revealed nanoparticles with a mean diameter of 75.5 nm and an iron content of 37.5 µg/mL. No cytotoxicity was observed when the concentration of Fe3O4-dextran-anti-β-HCG nanoparticles was <37.5 µg/mL. Fe3O4-dextran nanoparticles have a satisfactory potential to combine with β-HCG antibody. Agarose gel electrophoresis analysis of binding

  13. Polyol synthesis of Mn3+ substituted Fe3O4 nanoparticles: Cation distribution, structural and electrical properties

    Amir, Md.; Ünal, B.; Shirsath, Sagar E.; Geleri, M.; Sertkol, M.; Baykal, A.

    2015-09-01

    In this study, MnxFe2-xO4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanoparticles were synthesized by polyol route and the effect of Mn3+ substitution on structural and dielectric properties of Fe3O4 was studied. X-ray powder diffraction (XRD) patterns confirmed the single spinel ferrite phase formation (Rietveld analysis). Crystallite size of the synthesized materials lie in the range of 12-25 nm as calculated X-ray diffraction patterns using Scherrer's formula. The microstructural features were examined by SEM images. Cation distribution calculations confirmed Fe3+ ions have both tetrahedral and ochedral site preferences whereas Mn3+ ions mostly occupies tetrahedral A-site. The ac electrical and dielectric properties of Mn3+ ion substituted Fe3O4 nanoparticle show that there were significant changes in both conductivity and complex permittivity as well as dielectric loss tangent as Mn3+ ion concentration is varied from zero to unity. It is clearly seen that conductivity increases with increase in temperature which may be due to increase in hopping capability of charge carriers at higher temperatures. Detailed evaluation of analysis reveals that at higher frequencies there is less effect of temperature on conductivity which can be interpreted on the basis of interfacial, dipolar, ionic and electronic polarization as detailed above section in explanation of variation of dielectric loss. The dielectric permittivity shows dielectric behavior can be clarified on the basis of Koop's interpretations in accordance with two layer Maxwell-Wagner model by accounting for surface charges. The electrical and dielectric properties, i.e. ac/dc conductivity, real/complex dielectric permittivity, and dielectric loss (tan δ) decrease with Mn3+ ion doping in some aspects.

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

    Shen, Mao; Yu, Yujing; Fan, Guodong; Chen, Guang; Jin, Ying Min; Tang, Wenyuan; Jia, Wenping

    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

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

    Akbarzadeh A

    2012-02-01

    Full Text Available Abolfazl Akbarzadeh1, Haleh Mikaeili2, Nosratollah Zarghami3, Rahmati Mohammad3, Amin Barkhordari3, Soodabeh Davaran21Drug Applied Research Center, 2Tuberculosis and Lung Disease Research Center of Tabriz, 3Department of Clinical Biochemistry and Laboratory Medicine, Division of Medical Biotechnology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, IranBackground: Superparamagnetic iron oxide nanoparticles are attractive materials that have been widely used in medicine for drug delivery, diagnostic imaging, and therapeutic applications. In our study, superparamagnetic iron oxide nanoparticles and the anticancer drug, doxorubicin hydrochloride, were encapsulated into poly (D, L-lactic-co-glycolic acid poly (ethylene glycol (PLGA-PEG nanoparticles for local treatment. The magnetic properties conferred by superparamagnetic iron oxide nanoparticles could help to maintain the nanoparticles in the joint with an external magnet.Methods: A series of PLGA:PEG triblock copolymers were synthesized by ring-opening polymerization of D, L-lactide and glycolide with different molecular weights of polyethylene glycol (PEG2000, PEG3000, and PEG4000 as an initiator. The bulk properties of these copolymers were characterized using 1H nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared spectroscopy, and differential scanning calorimetry. In addition, the resulting particles were characterized by x-ray powder diffraction, scanning electron microscopy, and vibrating sample magnetometry.Results: The doxorubicin encapsulation amount was reduced for PLGA:PEG2000 and PLGA:PEG3000 triblock copolymers, but increased to a great extent for PLGA:PEG4000 triblock copolymer. This is due to the increased water uptake capacity of the blended triblock copolymer, which encapsulated more doxorubicin molecules into a swollen copolymer matrix. The drug encapsulation efficiency achieved for Fe3O4 magnetic nanoparticles

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

    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 μA·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.

  17. Paclitaxel conjugated Fe3O4@LaF3:Ce3+,Tb3+ nanoparticles as bifunctional targeting carriers for Cancer theranostics application

    Mangaiyarkarasi, Rajendiran; Chinnathambi, Shanmugavel; Karthikeyan, Subramani; Aruna, Prakasarao; Ganesan, Singaravelu

    2016-02-01

    The bi-functional Chitosan functionalized magnetite doped luminescent rare earth nanoparticles (Fe3O4@LaF3: Ce3+,Tb3+/chi NPs) as a carrier of paclitaxel (PTX) drug was designed using a co-precipitation and facile direct precipitation method. The synthesized nanoparticles are spherical in shape with a typical diameter of 19-37 nm respectively. They are water soluble, super paramagnetic and biocompatible, in which the amino groups on the nanoparticles surface are used for the conjugation with an anticancer drug, paclitaxel. The nature of PTX binding with Fe3O4@LaF3: Ce3+,Tb3+/chi nanoparticles were studied using X-ray diffraction, vibrating sample magnetometer and scanning electron micrograph. The nature of interactions between PTX and Fe3O4@LaF3: Ce3+,Tb3+/chi NPs due to complex formation were conceded out by various spectroscopic methods viz., UV-visible, steady state and excited state fluorescence spectroscopy. The photo-physical characterization reveals that the adsorption and release of PTX from Fe3O4@LaF3:Tb3+/chi nanoparticles is quicker when compared with other nanoparticles and also confirms that this may be due to the hydrogen bond formation between the hydroxyl group of drug and amino group of nanoparticles respectively. The maximum loading capacity and entrapment efficiency of 83.69% and 80.51% were attained at a ratio of 5:8 of PTX and Fe3O4@LaF3: Ce3+,Tb3+/chi NPs respectively. In addition with that, antitumoral activity study of PTX conjugated Fe3O4@LaF3:Tb3+/chi nanoparticles exhibits increased cytotoxic effects on A549 lung cancer cell lines than that of unconjugated PTX.

  18. Perspective of Fe3O4 Nanoparticles Role in Biomedical Applications.

    Ghazanfari, Mohammad Reza; Kashefi, Mehrdad; Shams, Seyyedeh Fatemeh; Jaafari, Mahmoud Reza

    2016-01-01

    In recent years, although many review articles have been presented about bioapplications of magnetic nanoparticles by some research groups with different expertise such as chemistry, biology, medicine, pharmacology, and materials science and engineering, the majority of these reviews are insufficiently comprehensive in all related topics like magnetic aspects of process. In the current review, it is attempted to carry out the inclusive surveys on importance of magnetic nanoparticles and especially magnetite ones and their required conditions for appropriate performance in bioapplications. The main attentions of this paper are focused on magnetic features which are less considered. Accordingly, the review contains essential magnetic properties and their measurement methods, synthesis techniques, surface modification processes, and applications of magnetic nanoparticles. PMID:27293893

  19. Perspective of Fe3O4 Nanoparticles Role in Biomedical Applications

    Mohammad Reza Ghazanfari

    2016-01-01

    Full Text Available In recent years, although many review articles have been presented about bioapplications of magnetic nanoparticles by some research groups with different expertise such as chemistry, biology, medicine, pharmacology, and materials science and engineering, the majority of these reviews are insufficiently comprehensive in all related topics like magnetic aspects of process. In the current review, it is attempted to carry out the inclusive surveys on importance of magnetic nanoparticles and especially magnetite ones and their required conditions for appropriate performance in bioapplications. The main attentions of this paper are focused on magnetic features which are less considered. Accordingly, the review contains essential magnetic properties and their measurement methods, synthesis techniques, surface modification processes, and applications of magnetic nanoparticles.

  20. Casp3/7-Instructed Intracellular Aggregation of Fe3O4 Nanoparticles Enhances T2 MR Imaging of Tumor Apoptosis.

    Yuan, Yue; Ding, Zhanling; Qian, Junchao; Zhang, Jia; Xu, Jinyong; Dong, Xuejiao; Han, Tao; Ge, Shuchao; Luo, Yufeng; Wang, Yuwei; Zhong, Kai; Liang, Gaolin

    2016-04-13

    Large magnetic nanoparticles or aggregates are advantageous in their magnetic resonance properties over ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (NPs), but the former are cleared faster from the blood pool. Therefore, the "smart" strategy of intracellular aggregation of USPIO NPs is required for enhanced T2-weighted MR imaging. Herein, employing an enzyme-instructed condensation reaction, we rationally designed a small molecule Ac-Asp-Glu-Val-Asp-Cys(StBu)-Lys-CBT (1) to covalently modify USPIO NPs to prepare monodispersive Fe3O4@1 NPs. In vitro results showed that Fe3O4@1 NPs could be subjected to caspase 3 (Casp3)-instructed aggregation. T2 phantom MR imaging showed that the transverse molar relaxivity (r2) of Fe3O4@1 NPs with Casp3 or apoptotic HepG2 cells was significantly larger than those of control groups. In vivo tumor MR imaging results indicated that Fe3O4@1 NPs could be specifically applied for enhanced T2 MR imaging of tumor apoptosis. We propose that the enzyme-instructed intracellular aggregation of Fe3O4 NPs could be a novel strategy for the design of "smart" probes for efficient T2 MR imaging of in vivo biomarkers. PMID:27031226

  1. Biopanning and characterization of peptides with Fe3O4 nanoparticles-binding capability via phage display random peptide library technique.

    You, Fei; Yin, Guangfu; Pu, Ximing; Li, Yucan; Hu, Yang; Huang, Zhongbin; Liao, Xiaoming; Yao, Yadong; Chen, Xianchun

    2016-05-01

    Functionalization of inorganic nanoparticles (NPs) play an important role in biomedical applications. A proper functionalization of NPs can improve biocompatibility, avoid a loss of bioactivity, and further endow NPs with unique performances. Modification with vairous specific binding biomolecules from random biological libraries has been explored. In this work, two 7-mer peptides with sequences of HYIDFRW and TVNFKLY were selected from a phage display random peptide library by using ferromagnetic NPs as targets, and were verified to display strong binding affinity to Fe3O4 NPs. Fourier transform infrared spectrometry, fluorescence microscopy, thermal analysis and X-ray photoelectron spectroscopy confirmed the presence of peptides on the surface of Fe3O4 NPs. Sequence analyses revealed that the probable binding mechanism between the peptide and Fe3O4 NPs might be driven by Pearson hard acid-hard base specific interaction and hydrogen bonds, accompanied with hydrophilic interactions and non-specific electrostatic attractions. The cell viability assay indicated a good cytocompatibility of peptide-bound Fe3O4 NPs. Furthermore, TVNFKLY peptide and an ovarian tumor cell A2780 specific binding peptide (QQTNWSL) were conjugated to afford a liner 14-mer peptide (QQTNWSLTVNFKLY). The binding and targeting studies showed that 14-mer peptide was able to retain both the strong binding ability to Fe3O4 NPs and the specific binding ability to A2780 cells. The results suggested that the Fe3O4-binding peptides would be of great potential in the functionalization of Fe3O4 NPs for the tumor-targeted drug delivery and magnetic hyperthermia. PMID:26896661

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

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

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

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

    2010-01-01

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

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

    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

  5. A Fluorescent Sensor for Zinc Detection and Removal Based on Core-Shell Functionalized Fe3O4@SiO2 Nanoparticles

    The magnetic Fe3O4@SiO2 nanoparticles (NPs) functionalized with 8-chloroacetylaminoquinoline as a fluorescent sensor for detection and removal of Zn2+ have been synthesized. The core-shell structures of the nanoparticles and chemical composition have been confirmed by TEM, XRD, FTIR, and XPS techniques. The addition of functionalized Fe3O4@SiO2 NPs into the acetonitrile solution of Zn2+ had an effect of visual color change as well as significant fluorescent enhancement. High-saturated magnetizations (24.7 emu/g) of functionalized Fe3O4@SiO2 NPs could help to separate the metal ions from the aqueous solution. The magnetic sensor exhibited high removal efficiency towards Zn2+ (92.37%). In this work, we provided an easy and efficient route to detect Zn2+ and simultaneously remove Zn2+.

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

    Huining L

    2013-11-01

    proliferative ability of choriocarcinoma, with a significant inhibitory effect on the transplanted choriocarcinoma tumor. Therefore, Fe3O4-dextran-anti-βHCG carrying Hpa ASODN is an effective gene therapy, and Fe3O4-dextran-anti-βHCG nanoparticles are a harmless and effective gene vector. Keywords: heparanase, antisense oligodeoxynucleotide, Fe3O4-dextran-anti-βHCG nanoparticles, choriocarcinoma, invasive ability

  7. Controlling dynamic SERS hot spots on a monolayer film of Fe3O4@Au nanoparticles by a magnetic field

    Guo, Qing-Hua; Zhang, Chen-Jie; Wei, Chao; Xu, Min-Min; Yuan, Ya-Xian; Gu, Ren-Ao; Yao, Jian-Lin

    2016-01-01

    A large surface-enhanced Raman scattering (SERS) effect is critically dependent on the gap distance of adjacent nanostructures, i.e., "hot spots". However, the fabrication of dynamically controllable hot spots still remains a remarkable challenge. In the present study, we employed an external magnetic field to dynamically control the interparticle spacing of a two-dimensional monolayer film of Fe3O4@Au nanoparticles at a hexane/water interface. SERS measurements were performed to monitor the expansion and shrinkage of the nanoparticles gaps, which produced an obvious effect on SERS activities. The balance between the electrostatic repulsive force, surface tension, and magnetic attractive force allowed observation of the magnetic-field-responsive SERS effect. Upon introduction of an external magnetic field, a very weak SERS signal appeared initially, indicating weak enhancement due to a monolayer film with large interparticle spacing. The SERS intensity reached maximum after 5 s and thereafter remained almost unchanged. The results indicated that the observed variations in SERS intensities were fully reversible after removal of the external magnetic field. The reduction of interparticle spacing in response to a magnetic field resulted in about one order of magnitude of SERS enhancement. The combined use of the monolayer film and external magnetic field could be developed as a strategy to construct hot spots both for practical application of SERS and theoretical simulation of enhancement mechanisms.

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

    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

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

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

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

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

    Graphical abstract: - Highlights: • The APAP degradation exhibited a pseudo-first-order kinetics pattern well. • The Fe3O4 was stable without significant leaching of iron to water during reaction. • XPS and EPR results show that Fe2+-Fe3+ cycle was answerable for radical generation. • The removal of APAP is a result of oxidation due to both OH• and SO4−• . - Abstract: Magnetic nano-scaled particles Fe3O4 were studied for the activation of peroxymonosulfate (PMS) to generate active radicals for degradation of acetaminophen (APAP) in water. The Fe3O4 MNPs were found to effectively catalyze PMS for removal of APAP, and the reactions well followed a pseudo-first-order kinetics pattern (R2 > 0.95). Within 120 min, approximately 75% of 10 ppm APAP was accomplished by 0.2 mM PMS in the presence of 0.8 g/L Fe3O4 MNPs with little Fe3+ leaching (<4 μg/L). Higher Fe3O4 MNP dose, lower initial APAP concentration, neutral pH, and higher reaction temperature favored the APAP degradation. The production of sulfate radicals and hydroxyl radicals was validated through two ways: (1) indirectly from the scavenging tests with scavenging agents, tert-butyl alcohol (TBA) and ethanol (EtOH); (2) directly from the electron paramagnetic resonance (ESR) tests with 0.1 M 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO). Plausible mechanisms on the radical generation from Fe3O4 MNP activation of PMS are proposed based on the results of radical identification tests and XPS analysis. It appeared that Fe2+-Fe3+ on the catalyst surface was responsible for the radical generation. The results demonstrated that Fe3O4 MNPs activated PMS is a promising technology for water pollution caused by contaminants such as pharmaceuticals

  12. A facile one-pot ultrasound assisted for an efficient synthesis of benzo[g]chromenes using Fe3O4/polyethylene glycol (PEG) core/shell nanoparticles.

    Safaei-Ghomi, Javad; Eshteghal, Fahime; Shahbazi-Alavi, Hossein

    2016-11-01

    In this research, a general synthetic method for the synthesis of benzo[g]chromenes has been developed using Fe3O4/polyethylene glycol (PEG) core/shell nanoparticle under ultrasonic irradiations. Compared to the conventional methods, ultrasound procedure showed several advantages including mild reaction conditions, high yield products, short reaction times, reusability of the catalyst and little catalyst loading. PMID:27245961

  13. Size-dependent cytotoxicity of Fe3O4 nanoparticles induced by biphasic regulation of oxidative stress in different human hepatoma cells

    Xie Y

    2016-07-01

    Full Text Available Yuexia Xie,1,2,* Dejun Liu,3,* Chenlei Cai,1,* Xiaojing Chen,1 Yan Zhou,1 Liangliang Wu,1 Yongwei Sun,3 Huili Dai,1,2 Xianming Kong,1,2 Peifeng Liu1,2 1Central Laboratory, 2State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, 3Department of Biliary-Pancreatic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: The application of Fe3O4 nanoparticles (NPs has made great progress in the diagnosis of disease and in the drug delivery system for cancer therapy, but the relative mecha­nisms of potential toxicity induced by Fe3O4 have not kept pace with its development in the application, which has hampered its further clinical application. In this article, we used two kinds of human hepatoma cell lines, SK-Hep-1 and Hep3B, to investigate the cytotoxic effects and the involved mechanisms of small Fe3O4 NPs with different diameters (6 nm, 9 nm, and 14 nm. Results showed that the size of NPs effectively influences the cytotoxicity of hepatoma cells: 6 nm Fe3O4 NPs exhibited negligible cytotoxicity and 9 nm Fe3O4 NPs affected cytotoxicity via cellular mitochondrial dysfunction and by inducing necrosis mediated through the mitochondria-dependent intracellular reactive oxygen species generation. Meanwhile, 14 nm Fe3O4 NPs induced cytotoxicity by impairing the integrity of plasma membrane and promoting massive lactate dehydrogenase leakage. These results explain the detailed mechanism of different diameters of small Fe3O4 NPs-induced cytotoxicity. We anticipate that this study will provide different insights into the cytotoxicity mechanism of Fe3O4 NPs, so as to make them safer to use in clinical application. Keywords: hepatoma cells, nanoparticles, cytotoxicity, mechanism, oxidative stress

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

    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

  15. Superparamagnetic Fe3O4 Nanoparticles: Synthesis by Thermal Decomposition of Iron(III) Glucuronate and Application in Magnetic Resonance Imaging.

    Patsula, Vitalii; Kosinová, Lucie; Lovrić, Marija; Ferhatovic Hamzić, Lejla; Rabyk, Mariia; Konefal, Rafal; Paruzel, Aleksandra; Šlouf, Miroslav; Herynek, Vít; Gajović, Srećko; Horák, Daniel

    2016-03-23

    Monodisperse superparamagnetic Fe3O4 nanoparticles coated with oleic acid were prepared by thermal decomposition of Fe(III) glucuronate. The shape, size, and particle size distribution were controlled by varying the reaction parameters, such as the reaction temperature, concentration of the stabilizer, and type of high-boiling-point solvents. Magnetite particles were characterized by transmission electron microscopy (TEM), as well as electron diffraction (SAED), X-ray diffraction (XRD), dynamic light scattering (DLS), and magnetometer measurements. The particle coating was analyzed by atomic absorption spectroscopy (AAS) and attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FTIR) spectroscopy. To make the Fe3O4 nanoparticles dispersible in water, the particle surface was modified with α-carboxyl-ω-bis(ethane-2,1-diyl)phosphonic acid-terminated poly(3-O-methacryloyl-α-D-glucopyranose) (PMG-P). For future practical biomedical applications, nontoxicity plays a key role, and the PMG-P&Fe3O4 nanoparticles were tested on rat mesenchymal stem cells to determine the particle toxicity and their ability to label the cells. MR relaxometry confirmed that the PMG-P&Fe3O4 nanoparticles had high relaxivity but rather low cellular uptake. Nevertheless, the labeled cells still provided visible contrast enhancement in the magnetic resonance image. In addition, the cell viability was not compromised by the nanoparticles. Therefore, the PMG-P&Fe3O4 nanoparticles have the potential to be used in biomedical applications, especially as contrast agents for magnetic resonance imaging. PMID:26928653

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

    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 β-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 β-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)

  17. h-BN Nanosheets as 2D Substrates to Load 0D Fe3 O4 Nanoparticles: A Hybrid Anode Material for Lithium-Ion Batteries.

    Duan, Zhi-Qiang; Liu, Yi-Tao; Xie, Xu-Ming; Ye, Xiong-Ying; Zhu, Xiao-Dong

    2016-03-18

    h-BN, as an isoelectronic analogue of graphene, has improved thermal mechanical properties. Moreover, the liquid-phase production of h-BN is greener since harmful oxidants/reductants are unnecessary. Here we report a novel hybrid architecture by employing h-BN nanosheets as 2D substrates to load 0D Fe3 O4 nanoparticles, followed by phenol/formol carbonization to form a carbon coating. The resulting carbon-encapsulated h-BN@Fe3 O4 hybrid architecture exhibits synergistic interactions: 1) The h-BN nanosheets act as flexible 2D substrates to accommodate the volume change of the Fe3 O4 nanoparticles; 2) The Fe3 O4 nanoparticles serve as active materials to contribute to a high specific capacity; and 3) The carbon coating not only protects the hybrid architecture from deformation but also keeps the whole electrode highly conductive. The synergistic interactions translate into significantly enhanced electrochemical performances, laying a basis for the development of superior hybrid anode materials. PMID:26833884

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

    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.

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

    Shen, Mao; Yu, Yujing; Fan, Guodong; Chen, Guang; Jin, Ying min; Tang, Wenyuan; Jia, Wenping

    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 averag...

  20. 靶向治疗用Fe3O4及其白蛋白包被磁性纳米粒子的制备%Preparation Fe3O4 Nanoparticles and HAS-Coated Magnetite Nanoparticals for Tumor Target Therapy

    谭家驹; 张春富; 冯彦林; 曹金全; 曹本洪; 尹端; 汪勇先

    2003-01-01

    目的制备用于肿瘤靶向治疗的Fe3O4及其白蛋白包被的磁性纳米粒子.方法采用部分还原法制备Fe3O4纳米粒子,通过微乳化方法制备了白蛋白包被的Fe3O4磁性纳米颗粒.结果Fe3O4粒径为10nm左右,X-射线粉末衍射分析显示Fe3O4纳米磁性微粒是典型的尖晶石构型;白蛋白包被的磁性纳米粒子直径在200nm左右.结论Fe3O4及其白蛋白包被的磁性纳米粒子适于用于肿瘤靶向治疗的进一步研究.%Objective:To prepare Fe3O4 magnetite nanoparticles and HSA- coated magnetite particles for the purpose of regional target therapy. Methods: To adopt partial reduction method to prepare the Fe3O4 nanoparticles:100 ml 0.01 mol/L Na2SO3 was added dropwise into 100 ml 0.06 mol/LFeCl3 solution under nitrogen gas flow.10%(V%) ammonia was added dropwise with rapid stirring until pH of the reaction solution reach 8. Heated at 70℃ with water bath for 15 min. Preparation of HAS- coated magnetite particles:To use microemulsion approach,with oleic acid as oil phase, mixture of HSA and magnetite solution as water phase and sp- 85 as emulsion agent.Results: Fe3O4 magnetite particles with about 10 nm in diameter and X - ray power diffraction show that the nanoparticles is γ- Fe2O3. HAS- coated Fe3O4 magnetite nanoparticles is characterized by TEM with diameter no more than 200 nm. Conclusions: Fe3O4 magnetite nanoparticles and HSA - coated magnetite particles is suitable for researching of regional target therapy.

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

    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

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

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

    2012-01-01

    For preoperative and intraoperative detection of tumor distribution, numerous multimodal contrast agents, such as magnetic nanoparticles (MNPs) with several examination indicators, are currently in development. However, complex materials, configuration, and cost are required for multimodal contrast agents, accompanied by a high possibility of toxicity and low popularity in clinics. Nevertheless, the magnetic labeling of MNPs using bioprobes should be feasible not only in preoperative magnetic resonance imaging (MRI), but also in intraoperative examination based on other magnetic properties. In this study, anti-alpha-fetoprotein (AFP)-mediated Fe(3)O(4) MNPs, injected into mice with liver tumors, were used to examine the characteristics of magnetic labeling. Using MRI and scanning superconducting-quantum-interference-device biosusceptometry (SSB), based on alternating current (AC) susceptibility, the magnetic labeling occurred significantly on the first day post-injection of anti-AFP magnetic fluid (MF), and then decreased over time. However, for both MF without antibodies and an anti-carcinoembryonic antigen MF, no magnetic labeling occured on the first day of their respective post-injection. The favorable agreement indicates that magnetic labeling possesses two magnetic characteristics: distortion of the imaging field and AC susceptibility. In addition, the results of the biopsy tests, anti-AFP staining, and Prussian blue staining show the same dynamics as those of magnetic methodologies and prove that bound MNPs on tumor tissue are rotatable by an AC magnetic field to express AC susceptibility. Therefore, with the simple configuration of antibody-mediated MNPs, magnetic labeling is also feasible for intraoperative examinations using SSB with high mobility and sensitivity. PMID:22787394

  3. Fe3O4@Ag magnetic nanoparticles for microRNA capture and duplex-specific nuclease signal amplification based SERS detection in cancer cells.

    Pang, Yuanfeng; Wang, Chongwen; Wang, Jing; Sun, Zhiwei; Xiao, Rui; Wang, Shengqi

    2016-05-15

    A functionalized Fe3O4@Ag magnetic nanoparticle (NP) biosensor for microRNA (miRNA) capture and ultrasensitive detection in total RNA extract from cancer cells was reported in this paper. Herein, Raman tags-DNA probes modified Fe3O4@Ag NPs were designed both as surface-enhanced Raman scattering (SERS) SERS and duplex-specific nuclease signal amplification (DSNSA) platform. Firstly, target miRNAs were captured to the surface of Fe3O4@Ag NPs through DNA/RNA hybridization. In the presence of endonuclease duplex specific nuclease (DSN), one target miRNA molecule could rehybrid thousands of DNA probes to trigger the signal-amplifying recycling. Base on the superparamagnetic of Fe3O4@Ag NPs, target miRNA let-7b can be captured, concentrated and direct quantified within a PE tube without any PCR preamplification treatment. The detection limit was 0.3fM (15 zeptomole, 50μL), nearly 3 orders of magnitude lower than conventional fluorescence based DSN biosensors for miRNA(∼100fM), even single-base difference between the let-7 family members can be discriminated. The result provides a novel proposal to combine the perfect single-base recognition and signal-amplifying ability of the endonuclease DSN with cost-effective SERS strategy for miRNA point-of-care (POC) clinical diagnostics. PMID:26749099

  4. Magnetic adsorbent constructed from the loading of amino functionalized Fe3O4 on coordination complex modified polyoxometalates nanoparticle and its tetracycline adsorption removal property study

    Ou, Jinzhao; Mei, Mingliang; Xu, Xinxin

    2016-06-01

    A magnetic polyoxometalates based adsorbent has been synthesized successfully through the loading of amino functionalized Fe3O4 (NH2-Fe3O4) on nanoparticle of a coordination complex modified polyoxometalates (CC/POMNP). FTIR illustrate there exist intense hydrogen bonds between NH2-Fe3O4 and CC/POMNP, which keep the stability of this adsorbent. At room temperature, this adsorbent exhibits ferromagnetic character with saturation magnetization of 8.19 emu g-1, which provides prerequisite for fast magnetic separation. Water treatment experiment illustrates this POM based magnetic adsorbent exhibits high adsorption capacity on tetracycline. The adsorption process can be described well with Temkin model, which illustrates the interaction between adsorbent and tetracycline plays the dominated role in tetracycline removal. The rapid, high efficient tetracycline adsorption ability suggests this POM based magnetic adsorbent exhibits promising prospect in medical and agriculture waste water purification. A magnetic polyoxometalates based adsorbent, which exhibits excellent tetracycline adsorption removal property has been synthesized through the loading of NH2-Fe3O4 on coordination complex modified polyoxometalates

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

    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.

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

    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.

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

    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-β-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 β-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.

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

    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

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

    Liu YC

    2012-03-01

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

  10. Synergistic effect of the combination of triethylene-glycol modified Fe3O4 nanoparticles and ultrasound wave on MCF-7 cells

    Cancer is a group of disease characterized by uncontrolled growth and spread of abnormal cells in the body. The clinical treatments for cancer include surgery, chemotherapy and radiotherapy. Currently, employing new approaches for treatment has attracted more attentions. One of these approaches is sonodynamic therapy, which is an analogous approach based on the synergistic effect of ultrasound and a chemical component referred to as sonosensitizer. Recent years applications of nanotechnology have witnessed a tremendous expansion of research in medicine especially in treatment of cancers. The combination of sonodynamic therapy and nanotechnology can introduce a new way for cancer therapy. In this study, we used therapeutic ultrasonic waves with intensity of 1 MHz and different concentrations of Fe3O4 nanoparticles, as sonosensitizer, to investigate their combination effect on MCF-7 cell line. Briefly, we divided cells into four different groups; control, cells which got in touch with nanoparticles, cells that with exposure to ultrasound waves and cells which were influenced with combination of nanoparticles and ultrasonic waves. Finally, cell viability assay was used for detection of cytotoxicity effects. Experimental results revealed a significant decrease in viability of cells, which were affected by the combined action of ultrasound field and Fe3O4 nanoparticles, compared to the separate exposure of Fe3O4 nanoparticles or ultrasonic field. The synergic effect of ultrasound waves and Fe ions might be due to the production of toxic free radicals. - Highlights: • We examined the combination effect of Fe3O4 nanoparticles and ultrasound wave on MCF7. • The combination effect featured significant cytotoxic effects. • The cytotoxic effect is due to the production of reactive oxygen species

  11. Synergistic effect of the combination of triethylene-glycol modified Fe3O4 nanoparticles and ultrasound wave on MCF-7 cells

    Ebrahimi Fard, Ali; Zarepour, Atefeh; Zarrabi, Ali; Shanei, Ahmad; Salehi, Hossein

    2015-11-01

    Cancer is a group of disease characterized by uncontrolled growth and spread of abnormal cells in the body. The clinical treatments for cancer include surgery, chemotherapy and radiotherapy. Currently, employing new approaches for treatment has attracted more attentions. One of these approaches is sonodynamic therapy, which is an analogous approach based on the synergistic effect of ultrasound and a chemical component referred to as sonosensitizer. Recent years applications of nanotechnology have witnessed a tremendous expansion of research in medicine especially in treatment of cancers. The combination of sonodynamic therapy and nanotechnology can introduce a new way for cancer therapy. In this study, we used therapeutic ultrasonic waves with intensity of 1 MHz and different concentrations of Fe3O4 nanoparticles, as sonosensitizer, to investigate their combination effect on MCF-7 cell line. Briefly, we divided cells into four different groups; control, cells which got in touch with nanoparticles, cells that with exposure to ultrasound waves and cells which were influenced with combination of nanoparticles and ultrasonic waves. Finally, cell viability assay was used for detection of cytotoxicity effects. Experimental results revealed a significant decrease in viability of cells, which were affected by the combined action of ultrasound field and Fe3O4 nanoparticles, compared to the separate exposure of Fe3O4 nanoparticles or ultrasonic field. The synergic effect of ultrasound waves and Fe ions might be due to the production of toxic free radicals.

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

    Yuen, Clement; Liu, Quan

    2014-03-01

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

  13. Magnetic magnetite (Fe3O4) nanoparticle synthesis and applications for lead (Pb2+) and chromium (Cr6+) removal from water.

    Rajput, Shalini; Pittman, Charles U; Mohan, Dinesh

    2016-04-15

    Magnetic magnetite (Fe3O4) nanoparticles synthesized by chemical co-precipitation were characterized using XRD, TEM, SEM-EDX, FT-IR, ED-XRF, PPMS, point of zero charge (pHpzc) and surface area measurements. As-prepared Fe3O4 nanoparticles were successful for aqueous Cr(6+) and Pb(2+) removal. Batch adsorption experiments systematically investigated the influence of pH, temperature, contact time and adsorbate/adsorbent concentration on Cr(6+) and Pb(2+) adsorption. Maximum Cr(6+) and Pb(2+) removal occurred at pH 2.0 and 5.0, respectively. Sorption data fit pseudo-second order kinetics, indicating a chemical adsorption. The Freundlich, Langmuir, Redlich-Peterson, Toth, Radke and Sips adsorption isotherm models were applied to describe equilibrium data. The Sips and Langmuir models best described Cr(6+) and Pb(2+) adsorption on magnetite nanoparticles, respectively. The maximum Langmuir adsorption capacities were 34.87 (Cr(6+)) and 53.11 (Pb(2+))mg/g at 45°C, respectively. Fe3O4 nanoparticles are promising potential adsorbents and exhibited remarkable reusability for metal ions removal in water and wastewater treatment. PMID:26859095

  14. Preparation and Analysis of Fe3O4 Magnetic Nanoparticles Used as Targeted-drug Carriers%磁性Fe3O4纳米粒子用作靶向药物载体的制备及分析

    赵原壁; 邱祖民; 黄佳英

    2008-01-01

    Fe3O4 magnetic nanoparticles were prepared by the aqueous co-precipitation of FeCl3·6H2O and FeCl2·4H2O with addition of ammonium hydroxide. The conditions for the preparation of Fe3O4 magnetic nanoparticles were optimized, and Fe3O4 magnetic nanoparticles obtained were characterized systematically by means of transmission electron microscope (TEM), dynamic laser scattering analyzer (DLS) and X-ray diffraction (XRD). The results revealed that the magnetic nanoparticles were cubic shaped and dispersive, with narrow size distribution and average diameter of 11.4nm. It was found that the homogeneous variation of pH value in the solution via the control on the dropping rate of aqueous ammonia played a critical role in size distribution. The magnetic response of the product in the magnetic field was also analyzed and evaluated carefully. A 32.6 mT magnetic field which is produced by four ferromagnets was found to be sufficient to excite the dipole moments of 0.05g Fe3O4 powder 2cm far away from the ferromagnets. In conclusion, the Fe3O4 magnetic nanoparticles with excellent properties were competent for the magnetic carriers of targeted-drug in future application.

  15. A Micro Rectangular-Shaped Long-Period Fiber Grating Coated With Fe3O4 Nanoparticle Thin Overlay For Magnetic Sensing

    Sheng-Feng Wang; Chia-Chin Chiang

    2015-01-01

    In this paper, we provide a novel micro rectangular-shaped long-period fiber grating (MRSLPFG) coated with Fe3O4 nanoparticles as the sensing material and packaged in polydimethylsiloxane (PDMS) for magnetic sensing application. The micro rectangular-shaped grating structures are fully dip coated with the magnetic fluid and heated to form a thin solid film. This thin overlay is used as the sensing media to measure the external magnetic flux density parallel to the optical fiber axis. Accordin...

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

    Huang KW

    2012-06-01

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

  17. Novel Functionalized Polythiophene-Coated Fe3O4 Nanoparticles for Magnetic Solid-Phase Extraction of Phthalates

    Siti Nor Atika Baharin

    2016-04-01

    Full Text Available Poly(phenyl-(4-(6-thiophen-3-yl-hexyloxy-benzylidene-amine (P3TArH was successfully synthesized and coated on the surface of Fe3O4 magnetic nanoparticles (MNPs. The nanocomposites were characterized by Fourier transform infra-red (FTIR, X-ray diffractometry (XRD, Brunauer-Emmett-Teller (BET surface area analysis, analyzer transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. P3TArH-coated MNPs (MNP@P3TArH showed higher capabilities for the extraction of commonly-used phthalates and were optimized for the magnetic-solid phase extraction (MSPE of environmental samples. Separation and determination of the extracted phthalates, namely dimethyl phthalate (DMP, diethyl phthalate (DEP, dipropyl phthalate (DPP, dibutyl phthalate (DBP, butyl benzyl phthalate (BBP, dicyclohexyl phthalate (DCP, di-ethylhexyl phthalate (DEHP and di-n-octyl phthalate (DNOP, were conducted by a gas chromatography-flame ionization detector (GC-FID. The best working conditions were as follows; sample at pH 7, 30 min extraction time, ethyl acetate as the elution solvent, 500-µL elution solvent volumes, 10 min desorption time, 10-mg adsorbent dosage, 20-mL sample loading volume and 15 g·L−1 concentration of NaCl. Under the optimized conditions, the analytical performances were determined with a linear range of 0.1–50 µg·L−1 and a limit of detection at 0.08–0.468 µg·L−1 for all of the analytes studied. The intra-day (n = 7 and inter-day (n = 3 relative standard deviations (RSD% of three replicates were each demonstrated in the range of 3.7–4.9 and 3.0–5.0, respectively. The steadiness and reusability studies suggested that the MNP@P3TArH could be used up to five cycles. The proposed method was executed for the analysis of real water samples, namely commercial bottled mineral water and bottled fresh milk, whereby recoveries in the range of 68%–101% and RSD% lower than 7.7 were attained.

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

    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

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

    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

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

    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.

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

    In this study, a novel hydrogel, chitosan (CS) crosslinked carboxymethyl-β-cyclodextrin (CM-β-CD) polymer modified Fe3O4 magnetic nanoparticles was synthesized for delivering hydrophobic anticancer drug 5-fluorouracil (CS-CDpoly-MNPs). Carboxymethyl-β-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 43.8 emu/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. - Graphical abstract: A novel nanocarrier, chitosan-coated magnetic drug carrier nanoparticle (CS-CDpoly-MNPs) is fabricated for the delivery of insoluble anticancer drug by grafting CM-β-CD onto the magnetite surface. The grafting of CM-dextrins onto the surface of Fe3O4 nanocrystal clusters can markedly increase the loading capacity of 5-Fu by virtue of CM-dextrins/5-Fu inclusion complex formation. The release of 5-Fu from nanocomposite

  2. Convenient Preparation and Characterization of Surface Carboxyl-functioned Fe3O4 Magnetic Nanoparticles%表面羧基化Fe3O4磁性纳米粒子的快捷制备及表征

    苏鹏飞; 陈国; 赵珺

    2011-01-01

    Hydrophilic magnetic nanoparticles have been widely applied in biological sciences. In this work, we proposed a convenient method to synthesize surface carboxylic magnetic nanoparticles. Firstly, hydrophobic magnetic nanoparticles coated with oleic acid were prepared from ferric chloride and ferrous chloride by co-precipitation method, with oleic acid as surfactant. Then the C =C bond of oleic acid coated on the surface of particles was oxidized into -COOH by KMnO4 solution in situ, thereby hydrophobic magnetic nanoparticles functioned by monolayer carboxylic groups were obtained. The magnetic nanoparticles were characterized by transmission electron microscopy(TEM) , X-ray diffraction ( XRD ) , Fourier transform infrared ( FTIR) , ther-mogravimetric analysis( TGA) , vibrating sample magnetometry ( VSM) and Zeta potential analyzer and so on. The results showed that magnetic nanoparticles surface was successfully carboxyl-functioned. The average diameter and the saturation magnetization of the nanoparticles were about 9 nm and 64. 5 A · M2/kg, respectively. The remnant magnetization and coercivity of the nanoparticles were nearly to be 0, which demonstrated it was classic superparamagnetic. The carboxyl-functioned magnetic nanoparticles could be dispersed into water to form ferrofluid, which were stable for more than 42 d without precipitation at pH values of 7-10.%提出了一种快速对磁性纳米粒子表面羧基化的方法.以氯化铁和氯化亚铁为原料,油酸为表面活性剂,通过共沉淀法制得油酸包覆的亲油性Fe3O4磁性纳米粒子,然后用高锰酸钾进行原位氧化,将覆盖在粒子表面油酸中的C=C键氧化成-COOH,从而得到单层羧基功能化的亲水性磁性纳米粒子.利用透射电子显微镜(TEM),X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FTIR)、热重分析仪(TGA)、振动样品磁强计( VSM)和Zeta电位分析仪等对其进行了表征.结果表明,磁性纳米粒子的表面被成功羧基

  3. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-02-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5-20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures.

  4. An electrochemical sensor for rizatriptan benzoate determination using Fe3O4 nanoparticle/multiwall carbon nanotube-modified glassy carbon electrode in real samples.

    Madrakian, Tayyebeh; Maleki, Somayeh; Heidari, Mozhgan; Afkhami, Abbas

    2016-06-01

    In this paper a sensitive and selective electrochemical sensor for determination of rizatriptan benzoate (RZB) was proposed. A glassy carbon electrode was modified with nanocomposite of multiwalled carbon nanotubes (MWCNTs) and Fe3O4 nanoparticles (Fe3O4/MWCNTs/GCE). The results obtained clearly show that the combination of MWCNTs and Fe3O4 nanoparticles definitely improves the sensitivity of modified electrode to RZB determination. The morphology and electroanalytical performance of the fabricated sensor were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), square wave voltammetry (SWV) and cyclic voltammetry (CV). Also, the effect of experimental and instrumental parameters on the sensor response was evaluated. The square wave voltammetric response of the electrode to RZB was linear in the range 0.5-100.0μmolL(-1) with a detection limit of 0.09μmolL(-1) under the optimum conditions. The investigated method showed good stability, reproducibility and repeatability. The proposed sensor was successfully applied for real life samples of blood serum and RZB determination in pharmaceutical. PMID:27040259

  5. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves.

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-01-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5-20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

  6. Facile One-pot Transformation of Iron Oxides from Fe2O3 Nanoparticles to Nanostructured Fe3O4@C Core-Shell Composites via Combustion Waves

    Shin, Jungho; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2016-01-01

    The development of a low-cost, fast, and large-scale process for the synthesis and manipulation of nanostructured metal oxides is essential for incorporating materials with diverse practical applications. Herein, we present a facile one-pot synthesis method using combustion waves that simultaneously achieves fast reduction and direct formation of carbon coating layers on metal oxide nanostructures. Hybrid composites of Fe2O3 nanoparticles and nitrocellulose on the cm scale were fabricated by a wet impregnation process. We demonstrated that self-propagating combustion waves along interfacial boundaries between the surface of the metal oxide and the chemical fuels enabled the release of oxygen from Fe2O3. This accelerated reaction directly transformed Fe2O3 into Fe3O4 nanostructures. The distinctive color change from reddish-brown Fe2O3 to dark-gray Fe3O4 confirmed the transition of oxidation states and the change in the fundamental properties of the material. Furthermore, it simultaneously formed carbon layers of 5–20 nm thickness coating the surfaces of the resulting Fe3O4 nanoparticles, which may aid in maintaining the nanostructures and improving the conductivity of the composites. This newly developed use of combustion waves in hybridized nanostructures may permit the precise manipulation of the chemical compositions of other metal oxide nanostructures, as well as the formation of organic/inorganic hybrid nanostructures. PMID:26902260

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

    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

  8. Fe3 O4 Nanoparticles Synthesis With Folic Acid-coupling and Marked Tumor Experimental Research%以叶酸偶联纳米 Fe3 O4颗粒的合成和标记肿瘤实验研究

    胡丰; 唐宁宁; 刘灿; 唐园园; 王少华; 尹朝奇; 周春姣; 周建大; 曾蔚

    2014-01-01

    目的:研究叶酸偶联的超顺磁Fe3 O4纳米颗粒对活体肝癌标记效果和MRI成像功能。方法:以铁盐、十二烷基苯磺酸和3-氨基丙基3-乙氧基硅烷为原料,通过共沉淀法合成了APTES修饰的超顺磁Fe3 O4纳米颗粒,通过酰胺化法合成了叶酸偶联的超顺磁Fe3 O4纳米颗粒,以X射线衍射仪、透射电镜、红外光谱仪、振动样品磁强计、动态光散射仪对合成材料进行表征,采用SRB法对叶酸偶联的超顺磁Fe3 O4纳米颗粒细胞进行安全性检测,同时建立活体瘤鼠动物模型,对其在叶酸偶联的超顺磁Fe3 O4纳米颗粒标记前后进行MRI成像对比检测,每个肿瘤组织块各取2套切片,分别行苏木素-伊红染色和普鲁士蓝染色,观察肿瘤组织光镜下形态及组织内含Fe情况。结果:所制备的叶酸偶联的Fe3 O4纳米颗粒为立方相的Fe3 O4,粒径约8 nm左右,水合直径25.7 nm,呈近似球形,表面分布有羧基等功能基团,呈超顺磁特性,饱和磁化强度为51 emu/g Fe。叶酸偶联的超顺磁Fe3 O4纳米颗粒对人皮肤成纤维细胞(HSF)的生长与生理盐水对照组的影响一样,无明显抑制细胞生长的表现。同时,磁共振成像和染色结果均显示肿瘤的存在。结论:叶酸偶联的超顺磁Fe3 O4纳米颗粒,不仅细胞毒性小,而且因其表面的叶酸与叶酸受体之间的高强结合力。同时,它能通过这种结合作用被高效介导进入肿瘤细胞内,增强MRI成像中肿瘤组织与周围正常组织的对比度,有利于肿瘤细胞的标记、示踪和靶向检测,是一种很有应用前景的肿瘤细胞靶向检测物质。%Objective:To research the labeling effect of folate-conjugated Fe3 O4 nanoparticles on hepatocellular carci-noma in vivo and the function of MRI imaging.Methods:ATPES-modified Fe3 O4 nanoparticles were synthesized through co-precipitation action using iron salt,sodium dodecyl

  9. Fast assembling microarrays of superparamagnetic Fe3O4@Au nanoparticle clusters as reproducible substrates for surface-enhanced Raman scattering

    Ye, Min; Wei, Zewen; Hu, Fei; Wang, Jianxin; Ge, Guanglu; Hu, Zhiyuan; Shao, Mingwang; Lee, Shuit-Tong; Liu, Jian

    2015-08-01

    It is currently a very active research area to develop new types of substrates which integrate various nanomaterials for surface-enhanced Raman scattering (SERS) techniques. Here we report a unique approach to prepare SERS substrates with reproducible performance. It features silicon mold-assisted magnetic assembling of superparamagnetic Fe3O4@Au nanoparticle clusters (NCs) into arrayed microstructures on a wafer scale. This approach enables the fabrication of both silicon-based and hydrogel-based substrates in a sequential manner. We have demonstrated that strong SERS signals can be harvested from these substrates due to an efficient coupling effect between Fe3O4@Au NCs, with enhancement factors >106. These substrates have been confirmed to provide reproducible SERS signals, with low variations in different locations or batches of samples. We investigate the spatial distributions of electromagnetic field enhancement around Fe3O4@Au NCs assemblies using finite-difference-time-domain (FDTD) simulations. The procedure to prepare the substrates is straightforward and fast. The silicon mold can be easily cleaned out and refilled with Fe3O4@Au NCs assisted by a magnet, therefore being re-useable for many cycles. Our approach has integrated microarray technologies and provided a platform for thousands of independently addressable SERS detection, in order to meet the requirements of a rapid, robust, and high throughput performance.It is currently a very active research area to develop new types of substrates which integrate various nanomaterials for surface-enhanced Raman scattering (SERS) techniques. Here we report a unique approach to prepare SERS substrates with reproducible performance. It features silicon mold-assisted magnetic assembling of superparamagnetic Fe3O4@Au nanoparticle clusters (NCs) into arrayed microstructures on a wafer scale. This approach enables the fabrication of both silicon-based and hydrogel-based substrates in a sequential manner. We have

  10. Liquid-phase deposition of TiO2 nanoparticles on core–shell Fe3O4@SiO2 spheres: preparation, characterization, and photocatalytic activity

    To prevent and avoid magnetic loss caused by magnetite core phase transition involving in high-temperature crystallization of amorphous sol–gel TiO2, core–shell Fe3O4@SiO2@TiO2 composite spheres were synthesized via non-thermal process of TiO2. First, core–shell Fe3O4@SiO2 particles were synthesized through a solvothermal method followed by a sol–gel process. Second, anatase TiO2 nanoparticles (NPs) were directly coated on Fe3O4@SiO2 surface by liquid-phase deposition method, which uses (NH4)2TiF6 as Ti source for TiO2 and H3BO3 as scavenger for F− ions at 50 °C. The morphology, structure, composition, and magnetism of the resulting composites were characterized and their photocatalytic activities were also evaluated. The results demonstrate that TiO2 NPs with an average size of 6–8 nm were uniformly deposited on the Fe3O4@SiO2 surface. Magnetic hysteresis curves indicate that the composite spheres exhibit superparamagnetic characteristics with a magnetic saturation of 32.5 emu/g at room temperature. The magnetic TiO2 composites show high photocatalytic performance and can be recycled five times by magnetic separation without major loss of activity, which meant that they can be used as efficient and conveniently renewable photocatalyst.

  11. 56Co-labelled radioactive Fe3O4 nanoparticles for in vitro uptake studies on Balb/3T3 and Caco-2 cell lines

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

  12. Synthesis, characterization and wound healing imitation of Fe3O4 magnetic nanoparticle grafted by natural products

    Pala, Sravan Kumar

    This research focused on the study of the core-shelled magnetic nanomaterials derived from a colloidal chemistry. The goals are four-fold: (1) synthesis of Fe3O4MNMs using colloidal chemistry. The Fe 3O4 MNMs were then grafted with extracts derived from natural products, namely Olecraceavar italica (broccoli), Boletus edulis (mushroom)and Solanum lycopersicum (tomato);(2)characterization of natural products by chromatography and mass spectrometry;(3) characterization of MNMs to determine their crystallinity, morphological and elemental composition by the state-of-the-art instruments; and (4) biological evaluation using Gram-negative and Gram-positive bacteria. The approach provides advantages to precisely control the composition and homogeneity. The second advantage of the colloidal chemistry is its user friendliness and feasibility. Due to the nature of the natural products, the compatibility of MNM is anticipated to be enhanced.In this chapter, the nanomaterials will be discussed from four perspectives,§1.1 Nanotechnology (§1.1), §1.2 Synthesis of nanomaterials; §1.3 The natural product extract,; §1.4 Characterization of nanomaterials; and §1.5Biological application of nanomaterials.Fig. 1 summarized the overarching goals of this study.

  13. Preparation and characterization of highly water-soluble magnetic Fe3O4 nanoparticles via surface double-layered self-assembly method of sodium alpha-olefin sulfonate

    A kind of double-layered self-assembly sodium alpha-olefin sulfonate (AOS) capped Fe3O4 magnetic nanoparticles (Fe3O4-AOS-MN) with highly water-solubility was prepared by a wet co-precipitation method with a pH of 4.8. The resulting Fe3O4-AOS-MN could be dispersed into water to form stable magnetic fluid without other treatments. The result of X-ray diffraction (XRD) indicated that the Fe3O4-AOS-MN maintained original crystalline structure and exhibited a diameter of about 7.5 nm. The iron oxide phase of nanoparticles determined by Raman spectroscopy is Fe3O4. Transmission electron microscopy (TEM) analysis confirmed that the Fe3O4-AOS-MN with spherical morphology were uniformly dispersed in water. FT-IR spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) verified the successful preparation of Fe3O4-AOS-MN capped with double-layered self-assembled AOS. The corresponding capacities of monolayer chemical absorption and the second-layer self-assembly absorption were respectively 4.07 and 14.71 wt% of Fe3O4-MN, which were much lower than those of other surfactants. Vibrating sample magnetometer (VSM) test result showed Fe3O4-AOS-MN possessed superparamagnetic behavior with the saturation magnetization value of about 44.45 emu/g. The blocking temperature TB of Fe3O4-AOS-MN capped with double-layered AOS is 170 K. - Highlights: • Double-layered self-assembly sodium alpha-olefin sulfonate (AOS) capped Fe3O4 magnetic nanoparticles are prepared by a wet co-precipitation method. • Double-layered Fe3O4-AOS-MN exhibits highly water-solubility. • The iron oxide phase is determined by Raman spectroscopy. • Fe3O4-AOS-MN capped with double-layered AOS possesses super-paramagnetic behavior. • The blocking temperature TB of Fe3O4-AOS-MN capped with double-layered AOS is 170 K

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

    Zahra Rezay Marand; Mitra Helmi Rashid Farimani; Nasser Shahtahmasebi

    2014-01-01

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

  15. Preparation and characterization of highly water-soluble magnetic Fe3O4 nanoparticles via surface double-layered self-assembly method of sodium alpha-olefin sulfonate

    Li, Honghong; Qin, Li; Feng, Ying; Hu, Lihua; Zhou, Chunhua

    2015-06-01

    A kind of double-layered self-assembly sodium alpha-olefin sulfonate (AOS) capped Fe3O4 magnetic nanoparticles (Fe3O4-AOS-MN) with highly water-solubility was prepared by a wet co-precipitation method with a pH of 4.8. The resulting Fe3O4-AOS-MN could be dispersed into water to form stable magnetic fluid without other treatments. The result of X-ray diffraction (XRD) indicated that the Fe3O4-AOS-MN maintained original crystalline structure and exhibited a diameter of about 7.5 nm. The iron oxide phase of nanoparticles determined by Raman spectroscopy is Fe3O4. Transmission electron microscopy (TEM) analysis confirmed that the Fe3O4-AOS-MN with spherical morphology were uniformly dispersed in water. FT-IR spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA) verified the successful preparation of Fe3O4-AOS-MN capped with double-layered self-assembled AOS. The corresponding capacities of monolayer chemical absorption and the second-layer self-assembly absorption were respectively 4.07 and 14.71 wt% of Fe3O4-MN, which were much lower than those of other surfactants. Vibrating sample magnetometer (VSM) test result showed Fe3O4-AOS-MN possessed superparamagnetic behavior with the saturation magnetization value of about 44.45 emu/g. The blocking temperature TB of Fe3O4-AOS-MN capped with double-layered AOS is 170 K.

  16. Aligned Structures of Fe3O4 Nanoparticles in a Curable Polymer Carrier Induced by a Magnetic Field

    FANG Wen-Xiao; HE Zhen-Hui; XU Xue-Qing; SHEN Hui

    2005-01-01

    @@ To understand the interaction in dipolar systems, it is necessary to investigate the structures formed by the interacting particles. We introduce a polymer acrylic resin carrier to fix the structures in the magnetic fluid(Fe3O4). An aligned structure is investigated, which is formed under a magnetic field, and fixed in the cured acrylic resin film by evaporating the solvent at room temperature. The aligned structure is confirmed with the help of optical microscopy and optical diffraction for the cured film. Furthermore, we find substructures by using a scanning electronic microscope. Based on the curable and observable structures, a platform can be developed for investigating the aligned structures and configurations dominant by dipolar interaction. This is also helpful for the development of magnetic devices with orderly aligned structures.

  17. Morphological, Thermal, and Magnetic Analysis of Ball-Milled γ-Fe2O3 and Fe3O4 Nanoparticles for Biomedical Application

    Burnham, Philip; Papaefthymiou, Georgia C.; Viescas, Arthur; Li, Calvin; Dollahon, Norman

    2013-03-01

    Superparamagnetic iron oxide nanoparticles are promising agents for hyperthermia cancer treatment, because, when exposed to an alternating magnetic field, they impart heat to surrounding tissue. A comparison of γ-Fe2O3 and Fe3O4 nanoparticles for such application is presented. The particles were obtained via surfactant-assisted high energy ball-milling in a hexane/oleic acid carrier-fluid environment. Particles with diameters of 5 to 16 nm were prepared with mass ratios (oleic acid):(γ-Fe2O3) of 0:1, 1:5, 1:10 and 1:20, with milling times of 3, 6, 9, and 12 hours. TEM micrographs revealed spherical morphology and the effect of oleic acid shells. Optimal size distributions were obtained for high oleic acid contents. At room temperature, a reduced internal magnetic field ~480 kOe) was recorded via Mössbauer spectroscopy compared to bulk γ-Fe2O3 ~500 kOe), due to magnetic relaxation; Fe3O4 particles produced similar results. For the γ-Fe2O3 and Fe3O4 nanoparticles with 20% oleic acid by mass, comparative ZFC/FC magnetization (Happ = 200 Oe in temperature range from 2 to 400 K) and hysteresis loops (T = 2 K and 300 K up to Happ = 6 kOe) were obtained. Thermal transport characteristics were verified by Specific Absorption Rate (SAR) measurements using an AC magnetic field (f = 282 kHz). Differences and similarities in behavior will be discussed.

  18. Magnetite Fe3O4 nanoparticles and hematite α-Fe2O3 uniform oblique hexagonal microdisks, drum-like particles and spindles and their magnetic properties

    Graphical abstract: Phase- and shape-controlled synthesis of the magnetite Fe3O4 nanoparticles and the hematite α-Fe2O3 uniform oblique hexagonal microdisks to drum-like particles and spindles has been realized by simply adjusting the volume ratio of ethylene glycol (EG) and water of the hydrothermal reaction medium solvent and the magnetic properties of the hematite α-Fe2O3 crystals express regular change with the shape evolution from uniform oblique hexagonal microdisks to drum-like particles, spindles and irregular particles. - Highlights: • Different morphology of hematite α-Fe2O3 was synthesized by a hydrothermal route. • The volume ratio of EG and distilled water is designed as 40:0–0:40. • The EG affects the morphology of the hematite α-Fe2O3 crystals. • A possible formation mechanism of hematite α-Fe2O3 has been proposed. • The magnetism performance has a significant change. - Abstract: Magnetite Fe3O4 nanoparticles and uniform hematite (α-Fe2O3) oblique hexagonal microdisks, drum-like particles, and spindles have been synthesized via a facile hydrothermal reaction route, in which the mixture solvents of ethylene glycol (EG) and water are used as reaction medium. The phase, size, shape and growth orientation of the synthesized iron oxide crystals were characterized by powder X-ray diffraction and electron microscopy. When the reaction medium is almost composed of EG, a lot of Fe3+ ions reduce to Fe2+ ions due to the effect of EG, resulting in the magnetite Fe3O4 nanoparticles. As the volume ratio of EG/water in the reaction medium is lower than 30:10, the reductive ability of EG is too low to reduce the Fe3+ ions to Fe2+ ions, leading to the hematite α-Fe2O3 crystals. Moreover, since the adsorption of EG on the crystals, the shape of the obtained hematite α-Fe2O3 crystals evolves from oblique hexagonal microdisks to drum-like particles, and spindles due to the decrease of EG in the mixture reaction medium solvent. The magnetic properties

  19. Removal of 4-Chlorophenol with Fe3O4 Nanoparticles/H2O2 System at High pH%高pH条件纳米Fe3O4催化H2O2分解去除水中4-氯酚

    赵志伟; 师杰; 刘杰

    2015-01-01

    In this paper, removal of 4⁃chlorophenom in aqueous solution with Fe3O4/H2O2 system was carried out at pH 5 to evaluate the catalytic efficiency of Fe3O4 to H2O2. The results showed that the as⁃synthesized nanoparticles was pure Fe3O4 and had an inverse spinel structure. Fe3O4 had a high catalytic activity for the H2O2 decomposition to oxidize the 4⁃chlorophenol in aqueous solution. The removal efficiency of 4⁃chlorophenol can reached 96.8%after 180 min. When the dosage of Fe3O4 was lower than 2.0 g/L, the removal efficiency of 4⁃chlorophenol was directly proportional to the dosage of Fe3O4, but inversely to the dosage of Fe3O4 when it was higher than 2.0 g/L. With the increase of the H2O2 dosage, the removal rate of 4⁃chlorophenol first increased and then reduced gradually. The initial pH of solution had great effect on the 4⁃chlorophenol removal. The lower pH lead to the higher removal effi⁃ciency of 4⁃chlorophenol. The catalytic activity of Fe3O4 was still high after 5 repeated experiments.%为了克服非均相fenton催化反应中溶液初始pH过低的缺点,开展了pH=5时Fe3O4/H2O2体系催化氧化去除水中4-氯酚实验。试验结果表明:制备的铁氧化物为纯Fe3O4,具有反尖晶石八面体结构。纳米Fe3O4能够高效催化H2O2分解氧化水中的4-氯酚,反应180 min后4-氯酚的去除率达到96.8%。当催化剂投量小于2.0 g/L,4-氯酚的去除率随着催化剂投量的增加而升高;当催化剂投量大于2.0 g/L,去除率会随着投量的增加而降低。随着H2O2投量的增加,4-氯酚的去除率先升高后降低。溶液的初始pH对4-氯酚的去除影响较大,pH越低,去除速率和效率越高。重复使用5次以后,纳米Fe3O4仍然保持较高的催化活性。

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

    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.

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

    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

  2. Synthesis of water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 and its catalytic application in Kabachnik-Fields multicomponent reaction

    Rostamnia, Sadegh; Doustkhah, Esmail

    2015-07-01

    Water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 were successfully synthesized. β-Cyclodextrin acts as stabilizer and structure directing agent of Fe3O4. Subsequently, the dispersion of Fe3O4@β-CD was applied for the Kabachnik-Fields multicomponent reaction through three-component synthesis of an amine, aldehyde, and dimethylphosphonate. β-CD had also a drastic effect in accelerating the catalysis of phosphonate synthesis. By this protocol, phosphonate derivatives were synthesized in high yields and the catalyst was recycled for 10 successful runs.

  3. Conductive Fe3O4 Nanoparticles Accelerate Syntrophic Methane Production from Butyrate Oxidation in Two Different Lake Sediments

    Zhang, Jianchao; Lu, Yahai

    2016-01-01

    Syntrophic methanogenesis is an essential link in the global carbon cycle and a key bioprocess for the disposal of organic waste and production of biogas. Recent studies suggest direct interspecies electron transfer (DIET) is involved in electron exchange in methanogenesis occurring in paddy soils, anaerobic digesters, and specific co-cultures with Geobacter. In this study, we evaluate the possible involvement of DIET in the syntrophic oxidation of butyrate in the enrichments from two lake sediments (an urban lake and a natural lake). The results showed that the production of CH4 was significantly accelerated in the presence of conductive nanoscale Fe3O4 or carbon nanotubes in the sediment enrichments. Observations made with fluorescence in situ hybridization and scanning electron microscope indicated that microbial aggregates were formed in the enrichments. It appeared that the average cell-to-cell distance in aggregates in nanomaterial-amended enrichments was larger than that in aggregates in the non-amended control. These results suggested that DIET-mediated syntrophic methanogenesis could occur in the lake sediments in the presence of conductive materials. Microbial community analysis of the enrichments revealed that the genera of Syntrophomonas, Sulfurospirillum, Methanosarcina, and Methanoregula were responsible for syntrophic oxidation of butyrate in lake sediment samples. The mechanism for the conductive-material-facilitated DIET in butyrate syntrophy deserves further investigation. PMID:27597850

  4. A facile "turn-on" fluorescent method with high sensitivity for Hg(2+) detection using magnetic Fe3O4 nanoparticles and hybridization chain reactions.

    Lv, Xiaoxiao; Wu, Wenchen; Niu, Chenggang; Huang, Dawei; Wang, Xiaoyu; Zhang, Xuegang

    2016-05-01

    In this manuscript, the authors molecularly engineered a hybridization chain reactions (HCRs) based probe on magnetic Fe3O4 nanoparticles for the sensitive detection of Hg(2+). The sensing system comprised three probes: capture probe H1, report probe H2, and report probe H3. The capture probe was modified on the surface of magnetic Fe3O4 nanoparticles. The report probes were labeled with fluorescein isothiocyanate (FITC). Without Hg(2+), the report probes were stable as molecular beacons in solution. In the presence of Hg(2+), the T-rich capture probes and report probes will hybridize into double-helical DNA domains with the aid of T-Hg(2+)-T coordination chemistry. Trigged by this reaction, more molecular beacons open and form a super tandem structure. Herein, the fluorescence signal was magnified by capturing more report probes. Separating the target and captured report probes from reaction solution was benefit to decrease the background signal and interference from other metal ions. The detection limit of this method was about 0.36nM, which is much lower than the regulations of World Health Organization and U.S. Environmental Protection Agency on Hg(2+) in drink water. This proposed sensing strategy also showed favorable selectivity over other common metal ions. In addition, it has good practicability in real water samples. PMID:26946010

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

    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.

  6. A Micro Rectangular-Shaped Long-Period Fiber Grating Coated With Fe3O4 Nanoparticle Thin Overlay For Magnetic Sensing

    Sheng-Feng Wang

    2015-10-01

    Full Text Available In this paper, we provide a novel micro rectangular-shaped long-period fiber grating (MRSLPFG coated with Fe3O4 nanoparticles as the sensing material and packaged in polydimethylsiloxane (PDMS for magnetic sensing application. The micro rectangular-shaped grating structures are fully dip coated with the magnetic fluid and heated to form a thin solid film. This thin overlay is used as the sensing media to measure the external magnetic flux density parallel to the optical fiber axis. According to our experimental results, the phenomenon of the transmission loss of the MRSLPFG magnetic sensor was increased monotonically when the external applied magnetic flux density increased. As the external applied magnetic flux density was increased from 0 to 91.10 mT, the resonance attenuation dip of the MRSLPFG increased and the average sensitivity achieved during the experiments was 0.129 dB/mT. We infer that the aforementioned experimental results were due to the magnetostrictive effect exerted on the thin layer of Fe3O4 nanoparticles, which in turn induced slight longitudinal strains on the micro rectangular-shaped fiber grating structures under different magnetic flux density.

  7. Hydrothermal synthesis of superparamagnetic and red luminescent bifunctional Fe3O4@Mn2+-doped NaYF4:Yb/Er core@shell monodisperse nanoparticles and their subsequent ligand exchange in water

    Qin, Zhenli; Du, Sinan; Luo, Yang; Liao, Zhijian; Zuo, Fang; Luo, Jianbin; Liu, Dong

    2016-08-01

    We report the use of an efficient hydrothermal method to synthesize superparamagnetic and red luminescent bifunctional Fe3O4@Mn2+-doped NaYF4:Yb/Er nanoparticles (NPs) with core@shell structures via a seed-growth procedure. Oleic acid coated Fe3O4 (OA-Fe3O4) NPs were initially synthesized using a coprecipitation method. The as-synthesized OA-Fe3O4 NPs were then used as seeds, on which the red upconversion luminescent shell (Mn2+-doped NaYF4:Yb/Er) was formed. Furthermore, hydrophobic to hydrophilic surface modification of the Fe3O4@Mn2+-doped NaYF4:Yb/Er NPs was achieved via a ligand exchange method where oleic acid was displaced by a PEG phosphate ligand [PEG = poly(ethylene glycol)]. These materials were characterized by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, and vibrating sample magnetometry (VSM). The Fe3O4 cores were uniformly coated with a Mn2+-doped NaYF4:Yb/Er shell, and the bifunctional Fe3O4@Mn2+-doped NaYF4:Yb/Er NPs were monodispersed. Furthermore, the Fe3O4@Mn2+-doped NaYF4:Yb/Er NPs exhibited a saturated magnetization value of 6.2 emu/g and emitted red luminescence under a 980 nm laser. The obtained bifunctional Fe3O4@Mn2+-doped NaYF4:Yb/Er NPs may find potential applications in drug targeting, bioseparation, and diagnostic analysis. The synthetic method may be employed for the preparation of other bifunctional nanomaterials.

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

    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.

  9. A nanocomposite consisting of graphene oxide and Fe3O4 magnetic nanoparticles for the extraction of flavonoids from tea, wine and urine samples

    We describe a single-step solvothermal method for the preparation of nanocomposites consisting of graphene oxide and Fe3O4 nanoparticles (GO/Fe3O4). This material is shown to be useful as a magnetic sorbent for the extraction of flavonoids from green tea, red wine, and urine samples. The nanocomposite is taking advantage of the high surface area of GO and the magnetic phase separation feature of the magnetic sorbent. The nanocomposite is recyclable and was applied to the extraction of flavonoids prior to their determination by HPLC. The effects of amount of surfactant, pH value of the sample solution, extraction time, and desorption condition on the extraction efficiency, and the regeneration conditions were optimized. The limits of detection for luteolin, quercetin and kaempferol range from 0.2 to 0.5 ng∙ mL−1 in urine, from 3.0 to 6.0 ng∙mL−1 in green tea, and from 1.0 to 2.5 ng∙mL−1 in red wine. The recoveries are between 82.0 and 101.4 %, with relative standard deviations of <9.3 %. (author)

  10. Synthesis of water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 and its catalytic application in Kabachnik–Fields multicomponent reaction

    Water-dispersed magnetic nanoparticles (H2O-DMNPs) of β-cyclodextrin modified Fe3O4 were successfully synthesized. β-Cyclodextrin acts as stabilizer and structure directing agent of Fe3O4. Subsequently, the dispersion of Fe3O4@β-CD was applied for the Kabachnik–Fields multicomponent reaction through three-component synthesis of an amine, aldehyde, and dimethylphosphonate. β-CD had also a drastic effect in accelerating the catalysis of phosphonate synthesis. By this protocol, phosphonate derivatives were synthesized in high yields and the catalyst was recycled for 10 successful runs. - Highlights: • Fe3O4@β-CD as a nanomagnetically catalyst. • A reusable magnetic nanocatalyst synthesis using commercially available compounds. • Represents advantages, operational simplicity, no waste, higher yield and with easy workup

  11. Superhydrophobic and Magnetic Fe3O4/Polydopamine Composite Nanoparticle and Its Oil/Water Separation%超疏水磁性Fe3O4/聚多巴胺复合纳米颗粒及其油/水分离

    梁伟欣; 王贵元; 王奔; 张亚斌; 郭志光

    2013-01-01

    借助于多巴胺在Fe3O4纳米颗粒表面自聚合形成聚多巴胺薄膜制备出Fe3O4/聚多巴胺(Fe3O4/PD)复合纳米颗粒,利用扫描电子显微镜、透射电子显微镜、X射线衍射仪对样品的形貌、结构及成分进行分析.所制备的颗粒经1H,1H,2H,2H-全氟癸基三氯硅烷化学修饰后表现出超疏水性.有趣的是,超疏水性的Fe3O4/PD纳米颗粒包裹在水滴表面能形成磁性液珠,该液珠(4 μL)在亲水性玻璃表面上的接触角高达164°、滚动角为8°.这些磁性液珠具有良好的机械稳定性和强度,同时研究了外部磁场驱动液珠在平面、曲面、油相中运动.结果表明,磁性液珠能够有效应用于操作微流体装置中的液体输送.水滴在Fe3O4/PD纳米颗粒构成表面的接触角超过150°,而油滴则接近0°,因此,在磁场存在下,这些颗粒能用于吸收油水混合物中的油滴而实现油水分离.此外,回收的Fe3O4/PD纳米颗粒保持着超疏水性且能再次利用.%We report a simple approach to creating bifunctional Fe3O4/polydopamine (Fe3O4/PD) composite nanoparticles (NPs) with both superparamagnetic and superhydrophobic properties. The Fe3O4/PD NPs were prepared by virtue of dopa-mine self-polymerization under mild conditions. Their morphology, structure and composition of nanocomposites were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), respectively. The Fe3O4/PD NPs have uniform sizes in a narrow range of 100~300 nm. Magnetic measurement reveals the Fe3O4/PD NPs are superparamagnetic with saturation magnetization of 73.40 emu/g. The as-prepared particles showed su-perhydrophobicity after being modified by lH,lH,2H,2H-perfluorodecyltrichlorosilane. The Fe3O4 particles were also modified by fiuoroalkylsilane, and surface composed of the particles present a water contact angle (CA) of 117 °. This result indicated that plenty of phenolic hydroxyl groups in

  12. Facile synthesis of Fe3O4 nanoparticles decorated on 3D graphene aerogels as broad-spectrum sorbents for water treatment

    Li, Yong; Zhang, Ruofang; Tian, Xike; Yang, Chao; Zhou, Zhaoxin

    2016-04-01

    In order to develop efficient and environment benign sorbents for water purification, the macroscopic multifunctional magnetite-reduced graphene oxides aerogels (M-RGOs) with strong interconnected networks were prepared via a one pot solvothermal method of graphene oxide sheets adsorbing iron ions and in situ simultaneous deposition of Fe3O4 nanoparticles in ethylene glycol or triethylene glycol solvents. Such M-RGOs exhibited excellent sorption capacity to different contaminants, including oils, organic solvents, arsenite ions, as well as dyes. In addition, it was demonstrated that the M-RGOs could be used as column packing materials to manufacture column for water purification by filtration. The method proposed was proved to be versatile to induce synergistic assembly of RGO sheets with other functional metal oxides nanoparticles and as a kind of broad-spectrum sorbents for removing different types of contaminants in water purification, simultaneously.

  13. Superparamagnetism and metamagnetic transition in Fe3O4 nanoparticles synthesized via co-precipitation method at different pH

    In the present work, Fe3O4 nanoparticles have been synthesized via low temperature co-precipitation method at different pH (7.0, 11.0 and 12.4) with the aim to study the variation of pH on the structural, optical and magnetic properties of samples. Further, the sample synthesized at pH ~12.4 has been annealed at 230 °C for 10 h to study the effect of annealing on structural, optical and magnetic properties. X-ray diffraction (XRD) results reveal the formation of pure spinel phase with the space group Fd-3m. Further, XRD, FESEM and TEM results confirm the nanocrystalline nature of the as synthesized samples, and the particle size of the samples decreases as the pH increases and increases after annealing at 230 °C. FTIR analysis indicates that the sample synthesized at pH ~12.4 and the same sample annealed at 230 °C are pure spinel Fe3O4, whereas the samples synthesized at pH ~7.0 and 11.0 have small content of α-Fe2O3. The optical measurements of the as synthesized samples show two band gaps in all synthesized samples. Field dependent magnetization measurements (M–H) reveal superparamagnetic nature of all the synthesized samples at room temperature and ferromagnetic behavior at low temperature (~5 K). Furthermore, M–H plots measured at 5 K show presence of metamagnetic transition in all samples. The metamagnetic transition along with ferromagnetic behavior at low temperature in Fe3O4 nanoparticles are observed first time in the present work to the best of our knowledge. Further the value of magnetization decreases with decreasing particle size at both temperatures. The fitting of the field cooled (FC) temperature dependent magnetization (M–T) measurements data with modified Bloch-spin wave model with additional surface disorder term and mixed magnetic phases indicates surface spin disorder and mixed magnetic phases in the as synthesized samples, which may be the possible reason for the existence of metamagnetic transition in the samples. The correlation

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

    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. 超顺磁性Fe3O4纳米粒子的制备和表征%Preparation and Characterization of Super-paramagnetic Fe304 Nanoparticles

    文德; 刘妙丽; 李强林

    2011-01-01

    超顺磁性的Fe3O4纳米颗粒,因其具有许多独特的性质和潜在的应用前景,引起了人们的极大关注,是材料研究领域的一个持续热点.采用共沉淀法制得纳米Fe3O4,通过XRD、SEM等对样品进行表征,用VSM对样品进行磁性能测试.结果表明所得样品为纯反尖晶石结构的Fe3O4球形颗粒,平均粒径约为15nm.磁性能测试表明当外加磁场为6 kOe时,Fe3O4纳米粒子的磁化达到饱和,饱和磁化强度为63 A·m2·kg-1.在室温下,所制Fe3O4纳米粒子显示典型的超顺磁性,在生物医学、磁记录材料、磁流体复合材料、催化剂等方面有着潜在的应用前景.%The superparamagnetic Fe3O4 nanoparticle has been attracting great attention and is an important topic in the field of advanced materials, owing to its many unique properties and potential applications. In this paper, the superparamagnetic Fe3O4 nanoparticles were synthesized by the coprecipitation method, the prepared samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy( SEM), the magnetic properties measurement was performed by VSM. The results indicate that the average diameter of the spherical Fe3O4 with pure anti-spinel structure is i5 nm, and that magnetization of the magnetic powders get to saturation, the saturated magnetization is 63 A · m2 · kg-1 when the external field is at 6 kOe. The prepared Fe3O4 nanoparticles show a typical superparamagnetism at room temperature, there are enormous potential applications for the superparamagnetic Fe3O4 nanoparticles in various fields, such as biomedicine, information storage, magnetic fluids, catalysts, and so on.

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

    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.

  17. Reduction of hematite with ethanol to produce magnetic nanoparticles of Fe3O4, Fe1 - x O or Fe0 coated with carbon

    Tristão, Juliana C.; Ardisson, José D.; Sansiviero, Maria Terezinha C.; Lago, Rochel M.

    2010-01-01

    The production of magnetic nanoparticles of Fe3O4 or Fe0 coated with carbon and carbon nanotubes was investigated by the reduction of hematite with ethanol in a Temperature Programmed Reaction up to 950°C. XRD and Mössbauer measurements showed after reaction at 350°C the partial reduction of hematite to magnetite. At 600°C the hematite is completely reduced to magnetite (59%), wüstite (39%) and metallic iron (7%). At higher temperatures, carbide and metallic iron are the only phases present. TG weight losses suggested the formation of 3-56 wt.% carbon deposits after reaction with ethanol. It was observed by SEM images a high concentration of nanometric carbon filaments on the material surface. BET analyses showed a slight increase in the surface area after reaction. These materials have potential application as catalyst support and removal of spilled oil contaminants.

  18. Targeted delivery and pH-responsive release of stereoisomeric anti-cancer drugs using β-cyclodextrin assemblied Fe3O4 nanoparticles

    Wang, Congli; Huang, Lizhen; Song, Shengmei; Saif, Bassam; Zhou, Yehong; Dong, Chuan; Shuang, Shaomin

    2015-12-01

    The β-cyclodextrin assemblied magnetic Fe3O4 nanoparticles (β-CD-MNPs) were successfully fabricated via a layer-by-layer method. Possessing an average size 14 nm, good stability and super-paramagnetic response (Ms 64 emu/g), the resultant nanocomposites could be served as a versatile biocompatible platform for selective loading, targeted delivery and pH-responsive release of stereoisomeric doxorubicin (DOX) and epirubicin (EPI). 1H-nuclear magnetic resonance (1H NMR) and the computer simulation further give the evidence that partial anthracene ring of drug molecule is included by β-CD. In addition, non-toxic β-CD-MNPs have excellent biocompatibility on MCF-7 cells, and cellular uptake indicate that different amounts of DOX or EPI can be transported to targeting site and released from the internalized carriers. The results demonstrate that as-prepared β-CD-MNPs could be a very promising vehicle for DOX and EPI.

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

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

  20. Optimization of adsorption process of Cadmium ions from synthetic wastewater using synthesized iron magnetic nanoparticles (Fe3O4

    Leila Karimi Takanlu

    2014-10-01

    Conclusion: Magnetite nanoparticles exhibit high capability for removal of cadmium. The nanoparticles synthesized could be used at industrial scale because of having the magnetic property, which make them easily recovered from aqueous solution through applying a magnetic field.

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

    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 μmol L−1 with a remarkable sensitivity of 0.402 mA/μmol L−1. Under optimum conditions, the inhibition rates of pesticides were proportional to their concentrations in the range of 0.1–70 nmol L−1, 0.1–50 nmol L−1, 0.1–70 nmol L−1 and 0.1–100 nmol L−1 for malathion, chlorpyrifos, monocrotophos and endosulfan, respectively. The detection limit of the biosensor for all pesticides was 0.1 nmol L−1 at a signal-to-noise ratio of 3. The biosensor showed good reproducibility, no interference by metal ions and long-term stability. The measurement results obtained by the present biosensor were in good agreement with those obtained by the standard gas chromatography–mass spectrometry method. The biosensor was employed for the determination

  2. Superparamagnetic Fe3 O4 @SiO2 core-shell composite nanoparticles for the mixed hemimicelle solid-phase extraction of benzodiazepines from hair and wastewater samples before high-performance liquid chromatography analysis.

    Esmaeili-Shahri, Effat; Es'haghi, Zarrin

    2015-12-01

    Magnetic Fe3 O4 /SiO2 composite core-shell nanoparticles were synthesized, characterized, and applied for the surfactant-assisted solid-phase extraction of five benzodiazepines diazepam, oxazepam, clonazepam, alprazolam, and midazolam, from human hair and wastewater samples before high-performance liquid chromatography with diode array detection. The nanocomposite was synthesized in two steps. First, Fe3 O4 nanoparticles were prepared by the chemical co-precipitation method of Fe(III) and Fe(II) as reaction substrates and NH3 /H2 O as precipitant. Second, the surface of Fe3 O4 nanoparticles was modified with shell silica by Stober method using tetraethylorthosilicate. The Fe3 O4 /SiO2 composite were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. To enhance their adsorptive tendency toward benzodiazepines, cetyltrimethylammonium bromide was added, which was adsorbed on the surface of the Fe3 O4 /SiO2 nanoparticles and formed mixed hemimicelles. The main parameters affecting the efficiency of the method were thoroughly investigated. Under optimum conditions, the calibration curves were linear in the range of 0.10-15 μgmL(-1) . The relative standard deviations ranged from 2.73 to 7.07%. The correlation coefficients varied from 0.9930 to 0.9996. PMID:26412451

  3. Poly(N-isopropylacrylamide)-gated Fe3O4/SiO2 core shell nanoparticles with expanded mesoporous structures for the temperature triggered release of lysozyme.

    Yu, Erick; Galiana, Irene; Martínez-Máñez, Ramón; Stroeve, Pieter; Marcos, María D; Aznar, Elena; Sancenón, Félix; Murguía, José R; Amorós, Pedro

    2015-11-01

    Core-shell nanoparticles comprised of Fe3O4 cores and a mesoporous silica shell with an average expanded pore size of 6.07 nm and coated with a poly(N-isopropylacrylamide) (PNIPAM) layer (CS-MSNs-EP-PNIPAM) were prepared and characterized. The nanoparticles was loaded with (Ru(bipy)3(2+)) dye or an antibacterial enzyme, lysozyme, to obtain CS-MSNs-EP-PNIPAM-Ru(bipy)3(2+) and CS-MSNs-EP-PNIPAM-Lys, respectively. The lysozyme loading was determined to be 160 mg/g of nanoparticle. It was seen that Ru(bipy)3(2+) and lysozyme release was minimal at a room temperature of 25 °C while at physiological temperature (37 °C), abrupt release was observed. The applicability of the CS-MSNs-EP-PNIPAM-Lys was further tested with two Gram-positive bacteria samples, Bacillus cereus and Micrococcus luteus. At physiological temperature, the nanoparticles were shown to reduce bacterial growth, indicating a successful release of lysozyme from the nanoparticles. This nanoparticle system shows potential as a nanocarrier for the loading of similarly sized proteins or other species as a drug delivery platform. PMID:26335056

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

    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

  5. D, L-Sulforaphane Loaded Fe3O4@ Gold Core Shell Nanoparticles: A Potential Sulforaphane Delivery System.

    Kheiri Manjili, Hamidreza; Ma'mani, Leila; Tavaddod, Sharareh; Mashhadikhan, Maedeh; Shafiee, Abbas; Naderi-Manesh, Hossein

    2016-01-01

    A novel design of gold-coated iron oxide nanoparticles was fabricated as a potential delivery system to improve the efficiency and stability of d, l-sulforaphane as an anticancer drug. To this purpose, the surface of gold-coated iron oxide nanoparticles was modified for sulforaphane delivery via furnishing its surface with thiolated polyethylene glycol-folic acid and thiolated polyethylene glycol-FITC. The synthesized nanoparticles were characterized by different techniques such as FTIR, energy dispersive X-ray spectroscopy, UV-visible spectroscopy, scanning and transmission electron microscopy. The average diameters of the synthesized nanoparticles before and after sulforaphane loading were obtained ∼ 33 nm and ∼ 38 nm, respectively, when ∼ 2.8 mmol/g of sulforaphane was loaded. The result of cell viability assay which was confirmed by apoptosis assay on the human breast cancer cells (MCF-7 line) as a model of in vitro-cancerous cells, proved that the bare nanoparticles showed little inherent cytotoxicity, whereas the sulforaphane-loaded nanoparticles were cytotoxic. The expression rate of the anti-apoptotic genes (bcl-2 and bcl-xL), and the pro-apoptotic genes (bax and bak) were quantified, and it was found that the expression rate of bcl-2 and bcl-xL genes significantly were decreased when MCF-7 cells were incubated by sulforaphane-loaded nanoparticles. The sulforaphane-loaded into the designed gold-coated iron oxide nanoparticles, acceptably induced apoptosis in MCF-7 cells. PMID:26982588

  6. D, L-Sulforaphane Loaded Fe3O4@ Gold Core Shell Nanoparticles: A Potential Sulforaphane Delivery System

    Kheiri Manjili, Hamidreza; Ma’mani, Leila; Tavaddod, Sharareh; Mashhadikhan, Maedeh; Shafiee, Abbas; Naderi-Manesh, Hossein

    2016-01-01

    A novel design of gold-coated iron oxide nanoparticles was fabricated as a potential delivery system to improve the efficiency and stability of d, l-sulforaphane as an anticancer drug. To this purpose, the surface of gold-coated iron oxide nanoparticles was modified for sulforaphane delivery via furnishing its surface with thiolated polyethylene glycol-folic acid and thiolated polyethylene glycol-FITC. The synthesized nanoparticles were characterized by different techniques such as FTIR, energy dispersive X-ray spectroscopy, UV-visible spectroscopy, scanning and transmission electron microscopy. The average diameters of the synthesized nanoparticles before and after sulforaphane loading were obtained ∼ 33 nm and ∼ 38 nm, respectively, when ∼ 2.8 mmol/g of sulforaphane was loaded. The result of cell viability assay which was confirmed by apoptosis assay on the human breast cancer cells (MCF-7 line) as a model of in vitro-cancerous cells, proved that the bare nanoparticles showed little inherent cytotoxicity, whereas the sulforaphane-loaded nanoparticles were cytotoxic. The expression rate of the anti-apoptotic genes (bcl-2 and bcl-xL), and the pro-apoptotic genes (bax and bak) were quantified, and it was found that the expression rate of bcl-2 and bcl-xL genes significantly were decreased when MCF-7 cells were incubated by sulforaphane-loaded nanoparticles. The sulforaphane-loaded into the designed gold-coated iron oxide nanoparticles, acceptably induced apoptosis in MCF-7 cells. PMID:26982588

  7. Sub-10 nm Fe3O4@Cu2-xS core-shell nanoparticles for dual-modal imaging and photothermal therapy

    Tian, Qiwei

    2013-06-12

    Photothermal nanomaterials have recently attracted significant research interest due to their potential applications in biological imaging and therapeutics. However, the development of small-sized photothermal nanomaterials with high thermal stability remains a formidable challenge. Here, we report the rational design and synthesis of ultrasmall (<10 nm) Fe3O 4@Cu2-xS core-shell nanoparticles, which offer both high photothermal stability and superparamagnetic properties. Specifically, these core-shell nanoparticles have proven effective as probes for T 2-weighted magnetic resonance imaging and infrared thermal imaging because of their strong absorption at the near-infrared region centered around 960 nm. Importantly, the photothermal effect of the nanoparticles can be precisely controlled by varying the Cu content in the core-shell structure. Furthermore, we demonstrate in vitro and in vivo photothermal ablation of cancer cells using these multifunctional nanoparticles. The results should provide improved understanding of synergistic effect resulting from the integration of magnetism with photothermal phenomenon, important for developing multimode nanoparticle probes for biomedical applications. © 2013 American Chemical Society.

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

    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.

  9. Investigation of superparamagnetic (Fe3O4) nanoparticles and magnetic field exposures on CHO-K1 cell line

    Coker, Zachary; Estlack, Larry; Hussain, Saber; Choi, Tae-Youl; Ibey, Bennett L.

    2016-03-01

    Rapid development in nanomaterial synthesis and functionalization has led to advanced studies in actuation and manipulation of cellular functions for biomedical applications. Often these actuation techniques employ externally applied magnetic fields to manipulate magnetic nanomaterials inside cell bodies in order to drive or trigger desired effects. While cellular interactions with low-frequency magnetic fields and nanoparticles have been extensively studied, the fundamental mechanisms behind these interactions remain poorly understood. Additionally, modern investigations on these concurrent exposure conditions have been limited in scope, and difficult to reproduce. This study presents an easily reproducible method of investigating the biological impact of concurrent magnetic field and nanoparticle exposure conditions using an in-vitro CHO-K1 cell line model, with the purpose of establishing grounds for in-depth fundamental studies of the mechanisms driving cellular-level interactions. Cells were cultured under various nanoparticle and magnetic field exposure conditions from 0 to 500 μg/ml nanoparticle concentrations, and DC, 50 Hz, or 100 Hz magnetic fields with 2.0 mT flux density. Cells were then observed by confocal fluorescence microscopy, and subject to biological assays to determine the effects of concurrent extreme-low frequency magnetic field and nanoparticle exposures on cellnanoparticle interactions, such as particle uptake and cell viability by MTT assay. Current results indicate little to no variation in effect on cell cultures based on magnetic field parameters alone; however, it is clear that deleterious synergistic effects of concurrent exposure conditions exist based on a significant decrease in cell viability when exposed to high concentrations of nanoparticles and concurrent magnetic field.

  10. A novel hydrothermal approach for synthesizing α-Fe2O3, γ-Fe2O3 and Fe3O4 mesoporous magnetic nanoparticles

    A novel method to synthesize the three phases of iron oxide nanoparticles (hematite, maghemite and magnetite) using the same non-toxic inorganic precursors via a water–organic interface under the low temperature hydrothermal conditions is reported. The synthesized particles are characterized by Powder X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). The Brunauer–Emmett–Teller (BET) results reveal the mesoporous nature of the particles. The magnetic properties of the nanoparticles are studied by Vibrating Sample Magnetometer (VSM) at various low temperatures and also at room temperature. The XRD peaks corresponding to each sample clearly depict the presence of the respective phase of the as-prepared magnetic nanoparticles. The nanoparticles of maghemite and magnetite have saturation magnetization of 58.56 and 40.30 emu/g respectively at room temperature, whereas the particles of hematite possess very low saturation magnetization value of 1.89 emu/g. Further, the magnetization is studied at four different temperatures and the zero field cooled (ZFC) and field cooled (FC) magnetization are reported. - Graphical abstract: Display Omitted - Highlights: • Hematite, maghemite and magnetite are obtained under hydrothermal synthesis. • α-Fe2O3, γ-Fe2O3 and Fe3O4 prepared are mesoporous and nearly monodisperse. • Near superparamagnetism is observed at room temperature for maghemite and magnetite

  11. Magneto-transport study of magnetite (Fe3O4) nanoparticles between Au nanogap electrodes on surface-oxidized Si substrate

    We have studied the magneto-transport of magnetite (Fe3O4) nanoparticles (MNPs) between Au nanogap electrodes (ANGEs) on surface-oxidized Si substrate. The MNP sizes are approximately 40 nm and the 100 nm thick magnetite thin film (which is formed of the MNP aggregation) was prepared between and around the ANGEs by use of the RF reactive magnetron sputtering method. The distance between the ANGEs and the bridge width of the ANGEs are approximately 50 nm and 1.5 μm, respectively. The ANGEs were produced by the tilted-angle-deposition method. The optical microscope, scanning electron microscope and atomic force microscope were used to observe the sample surface structure and morphology. To investigate the crystal structure and crystallinity of the MNPs, the X-ray diffraction measurement was performed. The electrical resistance and magneto-resistance ratio of the MNPs between the ANGEs were measured as a function of temperature. The magneto-transport mechanism is discussed on the basis of the spin dependent transport. -- Highlights: ► Between Au nanogap electrodes, magnetite nanoparticle aggregation was prepared. ► Magnetite nanoparticle aggregation was produced by the RF magnetron sputtering method. ► Resistivity and magnetoresistance of magnetite nanoparticle aggregation were measured. ► We propose the tunneling magneto-resistance model due to amorphous-like grain boundaries. ► The model explains temperature dependence on resistivity and magneto-resistance

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

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

    2014-01-01

    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 th...

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

    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.

  14. Synthesis, characterization and application of polyglycerol coated Fe3O4 nanoparticles as a nano-theranostics agent

    Jahandar, Marzieh; Zarrabi, Ali; Shokrgozar, Mohammad Ali; Mousavi, Hajar

    2015-12-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) with an average size of 10 nm have been successfully synthesized by the polyol method. Then, hyperbranched polyglycerol (HPG) branches have been introduced on the surface of SPIONs through ring opening polymerization of glycidol as a biocompatible surface modifier with a more hydrophilic nature than other biomedical polymers. The as-synthesized SPION-HPGs were analyzed by FT-IR, CHNS and TGA analysis which all exhibited the successful HPG grafting onto the SPION surface. The anticancer herbal drug, curcumin, was loaded on the resultant nanocarrier. The MTT assay demonstrated the non-cytotoxicity effect of SPION-HPGs and the low cytotoxicity effect of curcumin at low concentrations on L929 and MCF-7 cell lines as normal and cancerous cells, respectively. Moreover, these nanoparticles exhibited an improved effect as a contrast agent in magnetic resonance imaging. Thus, it is concluded that SPION-HPG has the potential to be used in theranostics applications due to its simultaneous drug delivery and imaging capabilities.

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

    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...

  16. Magnetorelaxometry of few Fe3O4 nanoparticles at 77 K employing a self-compensated SQUID magnetometer

    Guillaume, Alexander; Scholtyssek, Jan M.; Lak, Aidin; Kassner, Alexander; Ludwig, Frank; Schilling, Meinhard

    2016-06-01

    Magnetic nanoparticles (MNPs) are of great interest for industrial and medical applications. Therefore, the properties of the particles have to be well controlled. Several magnetic measurement schemes have been developed in order to determine particle parameters such as size distribution and structural properties. In general, systems are designed either for the analysis of large amounts of MNP (≫1000) or for single particle investigation. Up to now, the region in between has been less studied. However, small and well defined amounts of MNPs are of high interest, e.g. for the systematic investigation of particle-particle interactions. In this paper, we present a method using electron beam lithographic preparation of small amounts of MNPs directly on a self-compensating high-temperature superconducting quantum interference device (SQUID) with micrometer dimensions which is insensitive to homogeneous fields and first order gradients but very sensitive to internal magnetic dipole fields. Magnetorelaxometry (MRX) measurements were carried out at 77 K sample temperature in a magnetically shielded room in order to analyze the dynamic behavior of MNP samples and to evaluate the detection limit of our SQUID sensors. Calculations based on the magnetic moment superposition model (MSM) and finite element simulations (FEM) indicate that the MNP samples can be fabricated in a well-defined way by the presented method. Based on MRX measurements of a sample with 200 single-core magnetite MNPs with core diameters of 12 nm, we estimate the detection limit of our SQUID MRX setup as 70 MNPs.

  17. Photocatalytic Property of Fe3O4/SiO2/TiO2 Core-Shell Nanoparticle with Different Functional Layer Thicknesses

    Junyang Li

    2014-01-01

    Full Text Available This study examined the different properties of Fe3O4/SiO2/TiO2 (FST core-shell nanoparticles encapsulated for one to five different times, represented as FST1 to FST5, respectively. These FST nanoparticles were obtained using the carbon reduction and sol-gel methods, and their properties were characterized by various tools, such as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibratory sample magnetometer, laser granularity apparatus, and specific surface area analyzer. The relationship between irradiation time and decoloration ratio indicates that FST2 demonstrated significant efficiency in the decolorization of methyl orange (MO under UV light. Further study on recycle activity showed that FST2 had a high decoloration rate after four cycles of photocatalysis, and its degradation of MO was well aligned with the apparent first-order kinetic equation. Furthermore, FST2 exhibited the highest apparent rate in the first cycle. All these results demonstrate that the recoverable FST2 possessed excellent photocatalytic activity while maintaining outstanding stability for further applications, such as managing environmental pollution.

  18. Anti-fish bacterial pathogen effect of visible light responsive Fe3O4@TiO2 nanoparticles immobilized on glass using TiO2 sol–gel

    This paper demonstrates a fish pathogen reduction procedure that uses TiO2 sol–gel coating Fe3O4@TiO2 powder on glass substrate. Such procedure can effectively relieve two constraints that haunt TiO2 sterilization applications: 1) the need for UV for overcoming the wide band gap of pure TiO2 and 2) the difficulty of its recovering from water for reuse. In the process, visible light responsive Fe3O4/TiO2 nanoparticles are synthesized and immobilized on glass using TiO2 sol–gel as the binder for fish bacterial pathogen disinfection test. After 3 h of visible light irradiation, the immobilized Fe3O4@TiO2's inhibition efficiencies for fish bacterial pathogen are, respectively, 50% for Edwardsiella tarda (BCRC 10670) and 23% for Aeromonas hydrophila (BCRC 13018)

  19. Preparation of thermo and pH-responsive polymer@Au/Fe3O4 core/shell nanoparticles as a carrier for delivery of anticancer agent

    In this work, a thermo and pH-responsive poly-N-isopropylacrylamide-co-itaconic acid containing thiol side groups were successfully synthesized to prepare Doxorubicin-loaded polymer@Au/Fe3O4 core/shell nanoparticles (DOX-NPs). Copolymer and NPs were fully characterized by FT-IR, HNMR, photo-correlation spectroscopy, SEM, X-ray diffraction, vibrating-sample magnetometer, thermal gravimetric analysis, and UV–Vis spectroscopy. The stimuli-responsive characteristics of NPs were evaluated by in vitro release study in simulated cancerous environment. The biocompatibility and cytotoxic properties of NPs and DOX-NPs are explored by MTT method. The prepared NPs with the size of 50 nm showed paramagnetic characteristics with suitable and stable dispersion at physiological medium and high loading capacity (up to 55 %) of DOX. DOX-NPs yielded a pH- and temperature-triggered release of entrapped drugs at tumor tissue environment (59 % of DOX release) compared to physiological condition (20 % of DOX release) during 48 h. In vitro cytotoxicity studies indicated that the NPs showed no cytotoxicity on A549 cells at different amounts after incubation for 72 h confirming its suitability as a drug carrier. DOX-NPs, on the other hand, caused an efficient anticancer performance as verified by MTT assay test. It was concluded that developed NPs by us in this study may open the possibilities for targeted delivery of DOX to the cancerous tissues

  20. Facile synthesis of magnetic-/pH-responsive hydrogel beads based on Fe3O4 nanoparticles and chitosan hydrogel as MTX carriers for controlled drug release.

    Wu, Juan; Jiang, Wei; Tian, Renbing; Shen, Yewen; Jiang, Wei

    2016-10-01

    In the present study, methotrexate (MTX)-encapsulated magnetic-/pH-responsive hydrogel beads based on Fe3O4 nanoparticles and chitosan were successfully prepared through a one-step gelation process, which is a very facile, economic and environmentally friendly route. The developed hydrogel beads exhibited homogeneous porous structure and super-paramagnetic responsibility. MTX can be successfully encapsulated into magnetic chitosan hydrogel beads, and the drug encapsulation efficiency (%) and encapsulation content (%) were 93.8 and 6.28%, respectively. In addition, the drug release studies in vitro indicated that the MTX-encapsulated magnetic chitosan hydrogel beads had excellent pH-sensitivity, 90.6% MTX was released from the magnetic chitosan hydrogel beads within 48 h at pH 4.0. WST-1 assays in human liver hepatocellular carcinoma cells (HepG2) demonstrated that the MTX-encapsulated magnetic chitosan hydrogel beads had good cytocompatibility and high anti-tumor activity. Therefore, our results revealed that the MTX-encapsulated magnetic chitosan hydrogel beads would be a competitive candidate for controlled drug release in the area of targeted cancer therapy in the near future. PMID:27464586

  1. Body distribution of SiO2-Fe3O4 core-shell nanoparticles after intravenous injection and intratracheal instillation.

    Smulders, Stijn; Ketkar-Atre, Ashwini; Luyts, Katrien; Vriens, Hanne; De Sousa Nobre, Sonia; Rivard, Camille; Van Landuyt, Kirsten; Baken, Stijn; Smolders, Erik; Golanski, Luana; Ghosh, Manosij; Vanoirbeek, Jeroen; Himmelreich, Uwe; Hoet, Peter Hm

    2016-06-01

    Nano-silicon dioxide (SiO2) is used nowadays in several biomedical applications such as drug delivery and cancer therapy, and is produced on an industrial scale as additive to paints and coatings, cosmetics and food. Data regarding the long-term biokinetics of SiO2 engineered nanoparticles (ENPs) is lacking. In this study, the whole-body biodistribution of SiO2 core-shell ENPs containing a paramagnetic core of Fe3O4 was investigated after a single exposure via intravenous injection or intratracheal instillation in mice. The distribution and accumulation in different organs was evaluated for a period of 84 days using several techniques, including magnetic resonance imaging, inductively coupled plasma mass spectrometry, X-ray fluorescence and X-ray absorption near edge structure spectroscopy. We demonstrated that intravenously administered SiO2 ENPs mainly accumulate in the liver, and are retained in this tissue for over 84 days. After intratracheal instillation, an almost complete particle clearance from the lung was seen after 84 days with distribution to spleen and kidney. Furthermore, we have strong evidence that the ENPs retain their original core-shell structure during the whole observation period. This work gives an insight into the whole-body biodistribution of SiO2 ENPs and will provide guidance for further toxicity studies. PMID:26525175

  2. Modeling and optimization of effective parameters on the size of synthesized Fe3O4 superparamagnetic nanoparticles by coprecipitation technique using response surface methodology

    Ghazanfari, Mohammad Reza; Kashefi, Mehrdad; Jaafari, Mahmoud Reza

    2016-05-01

    Generally, the statistical methods are defined as appropriate techniques to study the processes trends. In current research, the Fe3O4 superparamagnetic nanoparticles were synthesized by coprecipitation method. In order to investigate the size properties of synthesized particles, the experimental design was done using central composite method (CCD) of response surface methodology (RSM) while the temperature, pH, and cation ratio of reaction were selected as influential factors. After particles synthesis based on designed runs, the different responses such as hydrodynamic size of particles (both freeze dried and air dried), size distribution, crystallite size, magnetic size, and zeta potential were evaluated by different techniques i.e. dynamic light scattering (DLS), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Based on these results, the quadratic polynomial model was fitted for each response that could predict the response amounts. In following, the study of factors effects was carried out that showed the temperature, pH, and their interactions had higher effectiveness. Finally, by optimizing, it was clear that the minimum amounts of particle size (10.15 nm) and size distribution (13.01 nm) were reached in the minimum temperature (70 °C) and cation ratio (0.5) amounts and maximum pH amount (10.5). Moreover, the characterizations showed the particles size was about 10 nm while the amounts of Ms, Hc, and Mr were equal to 60 (emu/g), 0.2 (Oe) and 0.22 (emu/g), respectively.

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

    Highlights: ► We have demonstrated a facile method to prepare Fe3O4 nanoparticles and chitosan-coated Fe3O4 nanoparticles. ► α-Fe2O3 sensors prepared from those Fe3O4 materials have been investigated and compared. ► The results show potential application of α-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 α-Fe2O3 based gas sensors. Gas sensing measurements revealed that the α-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 α-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.

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

    Echevarria-Uraga JJ

    2012-05-01

    Full Text Available José J Echevarria-Uraga,1 Ignacio García-Alonso,2 Fernando Plazaola,3 Maite Insausti,3 Néstor Etxebarria,3 Alberto Saiz-López,4 Begoña Fernández-Ruanova51Radiology Department, Hospital de Galdakao-Usánsolo, Bizkaia, Spain; 2Experimental Surgery Laboratory, Medicine Faculty, University of the Basque Country, Bizkaia, Spain; 3Faculty of Science and Technology, University of the Basque Country, Bizkaia, Spain; 4Pathology Department, Hospital de Galdakao-Usánsolo, Bizkaia, Spain; 5Osatek SA Unidad del Hospital de Galdakao-Usánsolo, Bizkaia, SpainPurpose: To evaluate, in an experimental model, the reliability of MRI for determining whether a higher iron concentration was obtained in tumor tissue than in normal liver parenchyma after intra-arterial administration of Fe3O4 lipophilic nanoparticles.Materials and methods: WAG/RijCrl rats were inoculated in the left hepatic lobe with 25,000 syngeneic CC-531 colon adenocarcinoma cells, after which they were randomized into two groups: control (CG and infused (IG. After confirming tumor induction, the IG rats received intra-arterial suspensions of Fe3O4 nanoparticles (2.6 mg in Lipiodol® (0.15 mL. To calculate the iron concentration, [Fe], in the tumor and liver tissues of both groups of rats, measurements of signal intensity from the tumors, healthy liver tissue, and paravertebral muscles were made on a 1.5T MRI system in gradient-echo DP* and T2*-weighted sequences. In addition, samples were collected to quantify the [Fe] by inductively coupled plasma-mass spectrometry (ICP-MS, as well as for histological analysis. Statistical analysis was performed with non-parametric tests, and Bland–Altman plots were produced; P values <0.05 were considered significant.Results: In the CG rats (n = 23, the mean [Fe] values estimated by MRI and ICP-MS were 13.2 µmol • g-1 and 5.9 µmol • g-1, respectively, in the tumors, and 19.0 µmol • g-1 and 11.7 µmol • g-1, respectively, in the hepatic tissue

  5. The fate of iron nanoparticles in environmental waters treated with nanoscale zero-valent iron, FeONPs and Fe3O4NPs.

    Peeters, Kelly; Lespes, Gaëtane; Zuliani, Tea; Ščančar, Janez; Milačič, Radmila

    2016-05-01

    Among the different nanoparticles (NPs) that are used in the remediation of contaminated environmental waters, iron nanoparticles (FeNPs) are the most frequently applied. However, if these FeNPs remain in the waters after the treatment, they can cause a hazard to the environment. In this work the time dependent size distribution of iron particles was investigated in Milli-Q water, forest spring water and landfill leachate after a variety of FeNP treatments. The efficiency of the metal removal by the FeNPs was also examined. The concentrations of the metals in the aqueous samples were determined before and after the nano-remediation by inductively coupled plasma mass spectrometry (ICP-MS). The data revealed that the settling and removal of the FeNPs after the treatment of the waters was related to the sample characteristics and the ways of dispersing the NPs. When mixing was used for the dispersion, the nano zero-valent iron (nZVI), FeONPs and Fe3O4NPs settled quickly in the Milli-Q water, the forest spring water and the landfill leachate. Dispersion with tertramethylammonium hydroxide (TMAH) resulted in a slower settling of the iron aggregates. In the Milli-Q and forest spring waters treated with FeONPs and dispersed by TMAH, the nanosized iron remained in solution as long as 24 h after the treatment and could represent a potential threat in environmental waters with a low ionic strength. The removal of the metals strongly depended on the type of FeNPs, the chemical speciation of the elements and the sample matrix. If the FeNPs are contaminated by a particular metal, this contaminant could be, during the NPs treatment, released into the water that is being remediated. PMID:26971807

  6. Biocompatible polyurethane/thiacalix[4]arenes functionalized Fe3O4 magnetic nanocomposites: Synthesis and properties.

    Mohammadi, Abbas; Barikani, Mehdi; Lakouraj, Moslem Mansour

    2016-09-01

    In this study, a series of magnetic polyurethane/Fe3O4 elastomer nanocomposites were prepared by covalently embedding novel thiacalix[4]arenes (TC4As) functionalized Fe3O4 nanoparticles (TC4As-Fe3O4) which contain macrocycles with reactive hydroxyl groups. Surface functionalization of Fe3O4 nanoparticles with TC4As macrocycles as unique reactive surface modifier not only gives specific characteristics to Fe3O4 nanoparticles but also improves the interphase interaction between nanoparticles and the polyurethane matrices through covalent attachment of polymer chains to nanoparticle surfaces. The novel synthesized TC4As-Fe3O4 nanoparticles were characterized by FTIR, XRD, TGA, VSM and SEM analysis. Furthermore, the effect of functionalization of Fe3O4 nanoparticles on the various properties of resulting nanocomposites was studied by XRD, TGA, DMTA, SEM, and a universal tensile tester. It was found that the functionalization of nanoparticles with TC4As affords better mechanical and thermal properties to polyurethane nanocomposites in comparison with unmodified nanoparticles. The SEM analysis showed finer dispersion of TC4As-Fe3O4 nanoparticles than unmodified Fe3O4 nanoparticles within the polyurethane matrices, which arising from formation of covalent bonding between TC4As functionalized Fe3O4 nanoparticles and polyurethane matrices. Moreover, the investigation of in vitro biocompatibility of novel nanocomposites showed that these samples are excellent candidate for biomedical use. PMID:27207044

  7. Effects of combined delivery of extremely low frequency electromagnetic field and magnetic Fe3O4 nanoparticles on hepatic cell lines

    Ju, Huixiang; Cui, Yubao; Chen, Zhiqiang; Fu, Qinping; Sun, Mingzhong; Zhou, Ying

    2016-01-01

    Magnetic Fe3O4 nanoparticles (MNPs) have shown promise as drug carriers for treating lung and liver tumors in vivo. However, little is known about the combined delivery of these MNPs with a second approach, extremely low frequency electro-magnetic field (ELFF) exposure, which has been shown to have value for in vitro treatment of tumor cells. Here, ELFF and MNPs were combined to treat healthy (HL-7702) and cancerous (Bel-7402, HepG2) hepatic cells lines to explore the potential therapeutic effects, bio-mechanisms, and potential toxicity of a combined drug-free treatment in vitro. Flow cytometry for anti-AFP (alpha fetal protein) antibody, which coated the MNPs, indicated that the combined treatment induced Bel-7402 and HepG2 hepatoma cells lines into early apoptosis, without significant effects on healthy hepatic cells. This effect appeared to be mediated through cellular membrane ion metabolism. The presence of AFP-loaded MNPs strengthened the effects of ELFF on tumor cells, inducing a higher frequency of early apoptosis, while having minimal toxic effects on healthy HL-7702 cells. Western blotting revealed that the apoptosis-triggering BCL proteins were up regulated in hepatoma cells compared to healthy cells. Flow cytometry and patch-clamp studies revealed that this resulted from a higher MNP uptake ratio and greater cellular membrane ion exchange current in tumor cells compared to HL-7702 cells. Further, patch-clamp results showed that combining MNPs with ELFF treatment induces cells into early apoptosis through an ion metabolism disturbance in cells, similar to ELFF treatment. In brief, the combination of ELFF and MNPs had beneficial effects on tumor cells without significant toxicity on healthy cells, and these effects were associated with cellular MNP uptake.

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

    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

  9. Effects of combined delivery of extremely low frequency electromagnetic field and magnetic Fe3O4 nanoparticles on hepatic cell lines.

    Ju, Huixiang; Cui, Yubao; Chen, Zhiqiang; Fu, Qinping; Sun, Mingzhong; Zhou, Ying

    2016-01-01

    Magnetic Fe3O4 nanoparticles (MNPs) have shown promise as drug carriers for treating lung and liver tumors in vivo. However, little is known about the combined delivery of these MNPs with a second approach, extremely low frequency electro-magnetic field (ELFF) exposure, which has been shown to have value for in vitro treatment of tumor cells. Here, ELFF and MNPs were combined to treat healthy (HL-7702) and cancerous (Bel-7402, HepG2) hepatic cells lines to explore the potential therapeutic effects, bio-mechanisms, and potential toxicity of a combined drug-free treatment in vitro. Flow cytometry for anti-AFP (alpha fetal protein) antibody, which coated the MNPs, indicated that the combined treatment induced Bel-7402 and HepG2 hepatoma cells lines into early apoptosis, without significant effects on healthy hepatic cells. This effect appeared to be mediated through cellular membrane ion metabolism. The presence of AFP-loaded MNPs strengthened the effects of ELFF on tumor cells, inducing a higher frequency of early apoptosis, while having minimal toxic effects on healthy HL-7702 cells. Western blotting revealed that the apoptosis-triggering BCL proteins were up regulated in hepatoma cells compared to healthy cells. Flow cytometry and patch-clamp studies revealed that this resulted from a higher MNP uptake ratio and greater cellular membrane ion exchange current in tumor cells compared to HL-7702 cells. Further, patch-clamp results showed that combining MNPs with ELFF treatment induces cells into early apoptosis through an ion metabolism disturbance in cells, similar to ELFF treatment. In brief, the combination of ELFF and MNPs had beneficial effects on tumor cells without significant toxicity on healthy cells, and these effects were associated with cellular MNP uptake. PMID:27186307

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

    Thu Trang Mai, Thi; Thu Ha, Phuong; Pham, Hong Nam; Thu Huong Le, Thi; Linh Pham, Hoai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan

    2012-03-01

    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.

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

    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

  12. A highly efficient nano-Fe3O4 encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

    The functionalization of silica-coated Fe3O4 magnetic nanoparticles (Fe3O4@SiO2) using chlorosulfonic acid were afforded sulfonic acid-functionalized magnetic Fe3O4 nanoparticles (Fe3O4@SiO2–SO3H) that can be applied as an organic–inorganic hybrid heterogeneous catalyst. The used Fe3O4 magnetic nanoparticles are 18–30 nm sized that was rapidly functionalized and can be used as catalyst in organic synthesis. The prepared nanoparticles were characterized by X-ray diffraction analysis, magnetization curve, scanning electron microscope, dynamic laser scattering, and FT-IR measurements. The resulting immobilized catalysts have been successfully used in the synthesis of 1,8‐dioxo-octahydroxanthene derivatives under solvent free condition. This procedure has many advantages such as; a much milder method, a shorter reaction time, a wide range of functional group tolerance, and absence of any tedious workup or purification. Other remarkable features include the catalyst can be reused at least five times without any obvious change in its catalytic activity. This procedure also avoids hazardous reagents/solvents, and thus can be an eco-friendly alternative to the existing methods.Graphical AbstractA highly efficient nano-Fe3O4 encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

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

    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...

  14. Preparation of Fe3O4@PPy magnetic nanoparticles as solid-phase extraction sorbents for preconcentration and separation of phthalic acid esters in water by gas chromatography-mass spectrometry.

    Zhao, Hongyan; Huang, Manyan; Wu, Jianrong; Wang, Li; He, Hua

    2016-02-01

    The purpose of this paper is to introduce a solid-phase extraction method of separating and determining of phthalic acid esters (PAEs) by PPy-coated Fe3O4 magnetic nanoparticles (Fe3O4@PPy MNPs). In the process, nanoparticles were served as sorbents and the optimal conditions of the extraction have been explored. The composite was synthesized through the chemical oxidation method, combining pyrrole monomer with Fe3O4 magnetic ball in the form of aggregation state and the coated nanoparticles possessed core-shell construction. The PPy-coated Fe3O4 magnetic microspheres have been extensively characterized by transmission electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The optimum conditions were investigated by orthogonal experimental design, which was used to testing the influence of main factors and the interactions among them. The orthoplan is famous for the merit that it can study the whole experiments comprehensively through minimal tests. Under the optimal extraction conditions: 20mg of modified magnetite nanoparticles, eluting with acetic ester of 2mL, 40min of MSPE, eluting in 1h and 20mL of sample volume, good linearity (r(2)>0.9912) of all calibration curves was obtained in validation experiments. And the limits of detection (LODs) were from 0.006 to 0.021ng/mL. The recoveries in different sample matrices were in the range from 80.4% to 108.2% with relative standard deviations less than 12.8%. The present work demonstrates the applicability of the developed method for the determination of PAEs in water sample and the results justified that it can be applied successfully to the selective isolation and enrichment of PAEs in real water samples. PMID:26751591

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

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

  16. Enhanced stability and catalytic activity of immobilized α-amylase on modified Fe3O4 nanoparticles for potential application in food industries

    Enzymes play an essential role in catalyzing various reactions. However, their instability upon repetitive/prolonged use, elevated temperature, acidic or alkaline pH remains an area of concern. α-Amylase, a widely used enzyme in food industries for starch hydrolysis, was covalently immobilized on the surface of two developed matrices, amino-functionalized silica-coated magnetite nanoparticles (AFSMNPs) alone and covered with chitosan. The synthesis steps and characterizations of NPs were examined by FT-IR, VSM, and SEM. Modified nanoparticles with average diameters of 20–80 nm were obtained. Enzyme immobilization efficiencies of 89 and 74 were obtained for AFSMNPs and chitosan-coated AFSMNPs, respectively. The optimum pH obtained was 6.5 and 8.0 for the enzyme immobilized on AFSMNPs and chitosan-coated AFSMNPs, respectively. Optimum temperature for the immobilized enzyme shifted toward higher temperatures. Considerable enhancements in thermal stabilities were observed for the immobilized enzyme at elevated temperatures up to 80 °C. A frequent use experiment demonstrated that the immobilized enzyme retained 74 and 85 % of its original activity even after 20 times of repeated use in AFSMNPs and chitosan-coated AFSMNPs, respectively. Storage stability demonstrated that free enzyme lost its activity completely within 30 days. But, immobilized enzyme on AFSMNPs and chitosan-coated AFSMNPs preserved 65.73 and 78.63 % of its initial activity, respectively, after 80 days of incubation. In conclusion, a substantial improvement in the performance of the immobilized enzyme with reference to the free enzyme was obtained. Furthermore, the relative activities of immobilized enzyme are superior than free enzyme over the broader pH and temperature ranges.

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

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

    2013-03-01

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

  18. 不同形貌纳米Fe3O4粒子磁流体的稳定性及其流度学性能%Stability and Magneto-Rheological Properties of Magnetic Fluids Containing Fe3O4 Nano-Particles with Different Morphologies

    胡大为; 王燕民; 潘志东

    2012-01-01

    The stability and magneto-rheological behavior of magnetic fluids containing nano-particles of Fe3O4 with irregular,octa-hedron and six-party flake morphologies as solid phase materials were investigated.A test device for the magnetic fluid stability,which was designed and manufactured based on the principle of L–C oscillator circuit,was used to determine the optimum organic modifier and surfactant concentrations for the preparation of the stable magnetic fluids.The magneto-rheological properties of the magnetic fluids with the nano-particles with different morphologies were examined in the presence of a vertical or horizontal mag-netic field.The results show that the viscosity of magnetic fluid at various shear rates in the presence of a horizontal magnetic induc-tion(i.e.,180,350 and 500 Gs) could not vary.The rheologic behaviors of the magnetic fluid became a Bingham plastic fluid in the presence of a vertical magnetic induction(i.e.,360,740 and 1 130 Gs).The viscosity and shear stress of the magnetic fluids containing the nano-particles with octahedron shape changed with the applied magnetic field.%选用无规则、正八面体和六方片状形貌的纳米Fe3O4磁性颗粒作为磁流体固相材料,通过设计组装基于L–C振荡电路的磁流体稳定性测试仪,确定制备稳定磁流体的较佳表面改性活性剂和辅助表面活性剂用量。同时,对含有不同形貌磁性颗粒的磁流体在水平方向磁场以及竖直方向磁场中的磁流变学性能进行了研究。结果表明:在外加水平方向180、350、500Gs磁感应强度,磁流体的黏度、剪切应力基本不变,磁流体表现出Newtonian流体的流变学特性;在外加竖直方向360、740、1130Gs磁感应强度,磁流体表现出Bingham流体的流变学特性;对于含有正八面体形貌纳米Fe3O4颗粒的磁流体,其黏度和剪切应力随外加磁场的变化较大。

  19. Actinides selective extractants coated Fe3O4 for analytical preconcentration

    N,N,N',N'-tetraoctyl diglycolamide (TODGA) and bis(2-ethylhexy)phosphoric acid (HDEHP) were anchored on Fe3O4 nanoparticles under different chemical conditions. TODGA coated on magnetic nanoparticles Fe3O4 (Fe3O4 at the rate TODGA) captured representative actinides Am(III) and Pu(IV) at 3 M HNO3 with a very high efficiency. Contrary to this, Fe3O4 at the rate HDEHP sorbed Pu(IV) only. The quantification of Am(III) preconcentrated in Fe3O4 at the rate TODGA was carried out by subjecting directly to γ-spectrometry. The quantification of Pu(IV) sorbed in Fe3O4 at the rate HDEHP was carried out after removal of coating in dioxane based scintillator followed by liquid scintillation counting. (author)

  20. 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

    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 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

  1. TiO2 nanoparticles supported on the Fe3O4@SiO2 nanocomposites: a novel magnetic nanocatalyst for the synthesis of 2-aminothiazoles

    Nano TiO2 supported on the Fe3O4@SiO2 nanocomposites is introduced as a novel catalyst for the environmental synthesis of 2-aminothiazoles in PEG-200 as a green medium at room temperature. In this reaction, thiourea and N-bromosuccinimide were reacted with various ketones affording the desired 2-aminothiazole compounds. This green protocol has promising features for the reaction response such as simple procedure, high yields, and the ease of separation of pure product, short reaction time, and convenient manipulation. This catalyst was easily separated by an external magnet, and the recovered catalyst was reused several times without any significant loss of activity.Graphical abstract

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

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

  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

    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.

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

    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

  5. o-Vanillin functionalized mesoporous silica - coated magnetite nanoparticles for efficient removal of Pb(II) from water

    Culita, Daniela C.; Simonescu, Claudia Maria; Patescu, Rodica-Elena; Dragne, Mioara; Stanica, Nicolae; Oprea, Ovidiu

    2016-06-01

    o-Vanillin functionalized mesoporous silica - coated magnetite (Fe3O4@MCM-41-N-oVan) was synthesized and fully characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, N2 adsorption-desorption technique and magnetic measurements. The capacity of Fe3O4@MCM-41-N-oVan to adsorb Pb(II) from aqueous solutions was evaluated in comparison with raw mesoporous silica - coated magnetite (Fe3O4@MCM-41) and amino - modified mesoporous silica coated magnetite (Fe3O4@MCM-41-NH2). The effect of adsorption process parameters such us pH, contact time, initial Pb(II) concentration was also investigated. The adsorption data were successfully fitted with the Langmuir model, exhibiting a maximum adsorption capacity of 155.71 mg/g at pH=4.4 and T=298 K. The results revealed that the adsorption rate was very high at the beginning of the adsorption process, 80-90% of the total amount of Pb(II) being removed within the first 60 min, depending on the initial concentration. The results of the present work suggest that Fe3O4@MCM-41-N-oVan is a suitable candidate for the separation of Pb(II) from contaminated water.

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

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

  7. Fe3O4/carbon coated silicon ternary hybrid composite as supercapacitor electrodes

    Highlights: • Silicon was covered with carbon by thermal vapor deposition. • Carbon layer prevent exposure of silicon to reactive electrolyte. • Fe3O4 contents in the composites optimized for electrochemical performance. • Fe3O4/carbon coated Si exhibits higher electrochemical performance than raw Si. - Abstract: In this study, Fe3O4/carbon-coated Si ternary hybrid composites were fabricated. A carbon layer was directly formed on the surface of Si by the thermal vapor deposition. The carbon-coating layer not only prevented the contact between Si and reactive electrolyte but also provided anchoring sites for the deposition of Fe3O4. Fe3O4 nanoparticles were deposited on the surface of carbon-coated Si by the hydrazine reducing method. The morphology and structure of Fe3O4 and carbon layer were characterized via X-ray diffractometry, field emission scanning electron microscopy, field emission transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analyses. These characterizations indicate that a carbon layer was fully coated on the Si particles, and Fe3O4 particles were homogeneously deposited on the carbon-coated Si particles. The Fe3O4/carbon-coated Si electrode exhibited enhanced electrochemical performance, attributed to the high conductivity and stability of carbon layer and pseudocapacitive reaction of Fe3O4. The proposed ternary-hybrid composites may be potentially useful for the fabrication of high-performance electrodes

  8. 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

    Graphical abstract: Self assembling of bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid on Fe3O4-Ag core-shell nanoparticles and application of it for solid phase extraction of PAHs. Highlights: ► A novel sorbent for magnetic solid-phase extraction of PAHs was introduced. ► Silver was coated on Fe3O4 nanoparticles (MNPs) by reduction of AgNO3 with NaBH4. ► Bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid self-assembled on silver coated MNPs. ► Size, morphology, composition and properties of the nanoparticles were characterized. ► Extraction efficiency of the sorbent was investigated by extraction of five PAHs. - Abstract: 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 Fe3O4 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 μL 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 μg L−1 (R2 > 0.9980) and the LODs (S/N = 3) were obtained in the range of 0.02–0.10 μg L−1. Relative standard deviations (RSDs) for intra- and inter-day precision were 2.6–4.2% and 3.6–8.3%, respectively. In

  9. Preparation of iron oxide nanoparticles supported on magnesium oxide for producing high-quality single-walled carbon nanotubes%用于制备优质单壁碳纳米管管束的MgO负载Fe3O4纳米粒子的合成

    Wei-WenLiu; Azizan Aziz; Siang-PiaoChai; Abdul Rahman Mohamed; Ching-Thian Tye

    2011-01-01

    采用沉淀方法制备了直径分布狭窄的均匀Fe3O4纳米颗粒.Fe3O4纳粒形体几近一致,平均粒径为10.33 nm±2.99 nm(平均粒径±标准偏差).在超声作用下将MgO纳米颗粒分散在一定量Fe3O4纳米颗粒的水溶液中获得MgO负载Fe3O4的纳米颗粒.以甲烷为碳源,Fe3O4/MgO为催化剂,经化学气相沉积,在Fe3O4纳粒上制得了大量直径近乎均匀的单壁碳纳米管(SWCNTs)束.TEM显示:SWCNTs的平均直径1.22rm.热重分析显示:样品在400℃~600℃温度区间失重量约19%.拉曼光谱显示:SWCNTs的ID/IG的强度比为0.03,表明采用Fe3O4/MgO催化剂可制得高石墨化程度的单壁碳纳米管.%Fe3O4 nanoparticles with a narrow diameter distribution having an average diameter of 10.33 nm±2.99 nm( average diameter±standard deviation) were prepared by a precipitation method.The Fe3O4 nanoparticles were supported on MgO by mixing the MgO nanopowder with the required amount of Fe3O4 nanoparticles in water under extensive sonication.Single-walled carbon nanotubes (SWCNTs) were synthesized by the chemical vapor deposition (CVD) of methane over the Fe3O4/MgO catalyst.Transmission electron microscopy showed that a large number of SWCNT bundles of nearly uniform diameter were produced by the CVD method.The average diameter of the produced SWCNTs was ca.1.22nm.Thermogravimetric analysis showed that the weight loss was approximately 19% by oxidation of carbon in the temperature range of 400-680 ℃.The ratio of the intensity of the D-band to theG-band was 0.03,indicating that the SWCNTs were well-graphitized.

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

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

    2015-04-14

    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 μg 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. Removal of methyl orange from aqueous solution by Azolla filicoloides: Synthesis of Fe3O4 nano-particles and its surface modification by the extracted pectin of Azolla

    Roohan Rakhshaee; Masoud Giahi; Afshin Pourahmad

    2011-01-01

    The modified Fe3O4 nano-particles with the extracted pectin from the cell wall of Azolla filicoloides (FN-EP) can remove methyl orange as a water-soluble azo dye from waste water better than Azolla and the extracted pectin from Azolla (EPA), alone. It could be due to more crowding the main functional groups of uptake after binding pectin with nano-particles. Thermodynamic studies showed that adsorption equilibrium constant (KL) and maximum adsorption capacities (Qmax) were increased with decreasing temperature (exothermic). The maximum uptake capacity (Qmax) of dye by FN-EP in a batch reactor was 0.533, 0.498 and 0.446 mmol/g at 5, 25 and 50 ℃, respectively. The enthalpy change (AH) and entropy change (△S) were -15.31 kJ/mol and -0.02434 kJ/mol K, respectively.

  12. Effect of chitosan molecular weight on the formation of chitosan-pullulanase soluble complexes and their application in the immobilization of pullulanase onto Fe3O4-κ-carrageenan nanoparticles.

    Long, Jie; Xu, Enbo; Li, Xingfei; Wu, Zhengzong; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan; Zhan, Xiaobei

    2016-07-01

    The interactions between pullulanase and chitosans of different molecular weights (Mw) were comprehensively studied, and their applications in pullulanase immobilization onto Fe3O4-κ-carrageenan nanoparticles upon chitosan-pullulanase complexation were also evaluated. Chitosan (CS) complexation with pullulanase was found to be dependent on pH and chitosan Mw. The critical pH of structure-forming events during complexation shifted significantly (pchitosan (50kDa) compared to other chitosan types. Binding constants for the chitosan-pullulanase interaction increased in the following order: CS-500chitosan Mw. This study presents a technique for the production of immobilized pullulanase upon complexation that exhibits potential for applications in continuous syrup production. PMID:26920265

  13. Improvement of the stability and activity of immobilized trypsin on modified Fe3O4 magnetic nanoparticles for hydrolysis of bovine serum albumin and its application in the bovine milk.

    Atacan, Keziban; Çakıroğlu, Bekir; Özacar, Mahmut

    2016-12-01

    Trypsin (EC 3.4.21.4) was successfully immobilized on the surface of Fe3O4 magnetic nanoparticles that had been pre-treated with gallic acid (GA). Measurements of protein load by using Bradford assay and the trypsin-catalyzed hydrolysis of Nα-Benzoyl-dl-arginine 4-nitroanilide hydrochloride (BApNA) were made for the immobilized enzyme. By using magnetic nanoparticles, which provides easy separation and decent support material for enzyme immobilization with high surface area to volume ratio, and by employing biocompatible material gallic acid, immobilized enzyme system was synthesized along with improving trypsin activity and stability. Immobilized trypsin (TR) was more stable than the free one and demonstrated higher enzymatic activity at elevated temperatures (45-55°C) and in the alkaline pH region (6-10.5). Fe3O4 NPs-GA-TR retained 92% of its initial activity after 120days of storage at 4°C in sodium phosphate buffer (0.1M, pH 7.5), whereas the free trypsin maintained about 64% of its initial activity during the same storage period. In addition, activity of the immobilized trypsin was preserved 54.5% of its initial activity after eight times successive reuse. The Michaelis-Menten kinetic constant (Km) and maximum reaction velocity (Vmax) for free trypsin were 5.1mM and 23mM/min, respectively, whereas Km and Vmax values of immobilized trypsin were 7.88mM and 18.3mM/min, respectively. The performance of the immobilized trypsin was demonstrated by carrying out the hydrolysis of bovine serum albumin (BSA) within 1h, and the assay was performed by using liquid chromatography-mass spectrometry (LC-MS/MS) technique. The hydrolysis of bovine milk as a real food was investigated by immobilized trypsin using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). PMID:27374556

  14. Influence of the uniform electric field on viscosity of magnetic nanofluid (Fe3O4-EG)

    Monajjemi Rarani, E.; Etesami, N.; Nasr Esfahany, M.

    2012-11-01

    Viscosity of Fe3O4/ethylene glycol nanofluids under electric field (ac and dc) was investigated experimentally. Magnetic nanofluids were prepared by dispersing Fe3O4 nanoparticles in ethylene glycol using a sonicator. Experiments showed that dilute magnetic nanofluids (fluid exhibit Newtonian behavior. Viscosity of Fe3O4 / ethylene glycol nanofluids in electric field was measured using capillary tube viscometer. Electric field decreased the viscosity of magnetic nanofluids and base fluid. The viscosity reduction was more profound in higher volume concentrations of nanoparticles. dc electric field caused greater viscosity reduction in magnetic nanofluids relative to ac electric field while ac electric field showed greater reduction effect for base liquid.

  15. Reliable methods for silica coating of Au nanoparticles.

    Pastoriza-Santos, Isabel; Liz-Marzán, Luis M

    2013-01-01

    The inherent properties of silica, such as optical transparency, high biocompatibility, chemical and colloidal stability, controllable porosity, and easy surface modification, provide silica materials with a tremendous potential in biomedicine. Therefore, the coating of Au nanoparticles with silica largely contributes to enhance the important applications of metal nanoparticles in biomedicine. We describe in this chapter a number of reliable strategies that have been reported for silica coating of different types of Au nanoparticles. All descriptions are based on tested protocols and are expected to provide a reference for scientists with an interest in this field. PMID:23918330

  16. p[5HRE] AFPp-p53/PEI-Fe3O4 magnetic nanoparticle combined with magnetic fluid hyperthermia inhibit hepatoma cells%p[5HRE] AFPp-p53/PEI-Fe3O4磁性纳米颗粒联合磁流体热疗对肝癌细胞的抑制作用

    赵成桂; 袁晨燕; 吴国球

    2016-01-01

    目的:建立p[5HRE] AFPp-p53/PEI-Fe3O4磁性纳米颗粒靶向基因治疗和磁流体热疗系统用于肝癌的联合治疗,以提高治疗的安全性和有效性.方法:亚克隆基因重组法构建靶向肝癌的治疗基因p[5 HRE] AFPp-p53,并用限制性内切酶凝胶电泳法检测重组质粒是否构建成功;用共沉淀法制备磁性纳米颗粒PEI-Fe3O4,利用透射电镜、粒径仪、傅里叶转换红外光谱仪等对PEI-Fe3O4进行表征检测.MTT法检测PEI-Fe3O4转染p[HRE] AFPp-p53至不同细胞系后的细胞增殖及磁流体热疗和基因治疗联合作用对肝癌细胞HepG2的增值抑制作用.结果:成功制备载有靶向治疗基因的p[5HRE] AFPp-p53/PEI-Fe3O4磁性纳米颗粒,由其介导的基因治疗组与阴性及纳米颗粒对照组相比,明显抑制肝癌HepG2(AFP阳性)细胞[(0.592 ±0.041) vs (1.052 ±0.031)、(1.012-±0.021),P<0.01]和SMMC7721(AFP阴性)细胞(0.813 ±0.042) vs(1.073±0.032)、(1.182±0.052),P<0.01]的增殖活性,但对非肝癌细胞(L929和Lovo)增殖抑制作用无明显影响(P>0.05).基因治疗和磁流体热疗联合组与单独使用热疗组及基因治疗组相比显著增加HepG2细胞的增殖抑制率(76.11% vs 35.22%、42.92%,均P<0.01).结论:p[5HRE] AFPp-p53/PEI-Fe3O4磁性纳米颗粒对肝癌细胞具有特异性杀伤作用,并且能与磁流体热疗产生协同效应,是一种选择性高、治疗效果好的肿瘤治疗方法.

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

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

  18. Double-Layer Magnetic Nanoparticle-Embedded Silica Particles for Efficient Bio-Separation.

    San Kyeong

    Full Text Available Superparamagnetic Fe3O4 nanoparticles (NPs based nanomaterials have been exploited in various biotechnology fields including biomolecule separation. However, slow accumulation of Fe3O4 NPs by magnets may limit broad applications of Fe3O4 NP-based nanomaterials. In this study, we report fabrication of Fe3O4 NPs double-layered silica nanoparticles (DL MNPs with a silica core and highly packed Fe3O4 NPs layers. The DL MNPs had a superparamagnetic property and efficient accumulation kinetics under an external magnetic field. Moreover, the magnetic field-exposed DL MNPs show quantitative accumulation, whereas Fe3O4 NPs single-layered silica nanoparticles (SL MNPs and silica-coated Fe3O4 NPs produced a saturated plateau under full recovery of the NPs. DL MNPs are promising nanomaterials with great potential to separate and analyze biomolecules.

  19. A survey of approaches for morphological, optical, and transport characterization of Fe3O4 and γ-Fe2O3 nanoparticles

    Nanoparticles’ structure, size, morphology, and surface conditions have significant influence on their performance and considerable impact on their application in biosystems. In this study some methods of nanoparticle analysis including structural x-ray diffraction, scanning electron and transmission electron microscopy size distribution and morphology characterization, superconducting quantum interference device and Faraday method magnetic and temperature dependence of specific resistance measurements, infrared spectroscopy, and laser light scattering based estimation of particle size distribution are surveyed. These methods illustrate the importance of a versatile approach to nanoparticle characterization, as the basis for their selection for particular applications. Since the methods of synthesis crucially affect the nanoparticle characteristics, the presented characterization techniques could also help to choose the most appropriate one. (paper)

  20. Electrostatic vs steric stabilization of Fe3O4 and Co0.5Fe2.5O4 nanoparticles

    Puscasu, E.; Domocos, A.; Leostean, C.; Turcu, R.; Brinza, F.; Nadejde, C.; Iacomi, F.; Creanga, D.

    2015-12-01

    Magnetic nanoparticles of magnetite/maghemite and cobalt ferrite Co0.5Fe2.5O4 were stabilized in deionized water with perchloric acid and, respectively, sodium oleate in order to prevent agglomeration and sedimentation tendency aiming further biomedical applications. Results obtained through Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Nanoparticle Tracking Analysis (NTA), and Vibrating Sample Magnetometry (VSM) were discussed comparatively for the four suspensions highlighting specific microstructural and magnetic features of each type of soft magnetic colloidal nanomaterial on the background of coprecipitation method adjusting. The results entitled us to plan in the next research stage biological tests focused on such nanoparticle suspensions impact on cell cultures.

  1. Crystal structures and magnetic properties of magnetite (Fe3O4)/Polyvinyl alcohol (PVA) ribbon

    Ardiyanti, Harlina; Suharyadi, Edi; Kato, Takeshi; Iwata, Satoshi

    2016-04-01

    Ribbon of magnetite (Fe3O4)/Polyvinyl Alcohol (PVA) nanoparticles have been successfully fabricated with various concentration of PVA synthesized by co-precipitation method. Particle size of nanoparticles Fe3O4 sample and ribbon Fe3O4/PVA 25% sample is about 9.34 nm and 11.29 nm, respectively. The result of Vibrating Sample Magnetometer (VSM) showed that saturation magnetization value decreased from 76.99 emu/g to 15.01 emu/g and coercivity increased from 49.30 Oe to 158.35 Oe as increasing concentration of PVA. Atomic Force Microscopy (AFM) analysis showed that encapsulated PVA given decreasing agglomeration, controlled shape of nanoparticles Fe3O4 more spherical and dispersed. Surface roughness decreased with increasing concentration of PVA.

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

    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 μm 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.

  3. Phase stabilization of magnetite (Fe3O4) nanoparticles with B2O3 addition: A significant enhancement on the phase transition temperature

    Topal, Uğur; Aksan, Mehmet Ali

    2016-05-01

    Magnetite nanoparticles (MNPs) are extensively investigated for biomedical applications, particularly as contrast agents for Magnetic Resonance Imaging and as drug delivery agent and heat mediators for cancer therapy. Tuning the magnetic properties of the magnetite nanoparticles with doping of foreign atoms has a crucial importance for determining the application areas of these materials and so attracts much interests. On the other hand the doping with foreign atoms requires high temperature annealing, and it causes a phase transition to the hematite phase above 400 °C. In this work the phase transition temperature from the magnetite to the hematite phase has been increased by 200 °C, which is the highest enhancement reported in literature. It was achieved by addition of the appropriate amounts of B2O3. Our experiments indicates that the 5.0 wt% of B2O3 addition stabilizes and keeps the existence of single phase magnetite up to 600 °C.

  4. Superparamagnetic Fe3O4 nanoparticles: synthesis by thermal decomposition of iron(III) glucuronate and application in magnetic resonance imaging

    Patsula, Vitalii; Kosinová, L.; Lovrić, M.; Ferhatovic Hamzic, L.; Rabyk, Mariia; Konefal, Rafal; Paruzel, Aleksandra; Šlouf, Miroslav; Herynek, V.; Gajović, S.; Horák, Daniel

    2016-01-01

    Roč. 8, č. 11 (2016), s. 7238-7247. ISSN 1944-8244 R&D Projects: GA MŠk(CZ) LH14318; GA MŠk(CZ) LO1507; GA MŠk(CZ) ED1.1.00/02.0109 EU Projects: European Commission(XE) 316120 - GLOWBRAIN Institutional support: RVO:61389013 Keywords : superparamagnetic * nanoparticles * iron oxide Subject RIV: CD - Macromolecular Chemistry Impact factor: 6.723, year: 2014

  5. A multifunctional biphasic suspension of mesoporous silica encapsulated with YVO4:Eu3+ and Fe3O4 nanoparticles: synergistic effect towards cancer therapy and imaging

    Shanta Singh, N.; Kulkarni, Hrishikesh; Pradhan, Lina; Bahadur, D.

    2013-02-01

    Polyol mediated synthesized luminescent YVO4:Eu3+ nanoparticles (NPs) have been encapsulated in mesoporous silica nanoparticles (MSNs) using the sol-gel process. X-ray diffraction and Fourier transform infrared spectroscopy along with transmission electron microscopy confirm the encapsulation of the YVO4:Eu3+ NPs in the SiO2 matrix. N2 adsorption/desorption analysis confirms the mesoporous nature of the MSNs and YVO4:Eu3+-MSNs. No significant quenching of the YVO4:Eu3+ luminescence is observed for YVO4:Eu3+-MSNs. This nanocomposite has been tested as a potential drug carrier. Efficient loading of doxorubicin hydrochloride (DOX), a typical anticancer drug, is observed which reaches up to 93% in 8 mg ml-1 of YVO4:Eu3+-MSNs. pH sensitive release of DOX is observed, with 54% release for pH 4.3 and 31% in a physiological environment (pH 7.4). Both MSNs and YVO4:Eu3+-MSNs nanocomposites do not show accountable toxicity to two cell lines, i.e. HeLa and MCF-7. However, as desired, toxicity is observed when cells are incubated with DOX loaded YVO4:Eu3+-MSNs. Laser scanning confocal microscopy images confirm the uptake of the nanocomposite in both cell lines. The morphology of the cells (MCF-7) changes after incubation with DOX loaded YVO4:Eu3+-MSNs, indicating an interaction of DOX with the cells. More cytotoxicity to both cell lines with ˜90% killing is observed due to the synergistic effect of magnetic fluid hyperthermia and chemotherapy using a biphasic suspension of superparamagnetic iron oxide magnetic nanoparticles and DOX loaded YVO4:Eu3+-MSNs. In addition, an AC magnetic field triggers an enhanced drug release.

  6. A multifunctional biphasic suspension of mesoporous silica encapsulated with YVO4:Eu3+ and Fe3O4 nanoparticles: synergistic effect towards cancer therapy and imaging

    Polyol mediated synthesized luminescent YVO4:Eu3+ nanoparticles (NPs) have been encapsulated in mesoporous silica nanoparticles (MSNs) using the sol–gel process. X-ray diffraction and Fourier transform infrared spectroscopy along with transmission electron microscopy confirm the encapsulation of the YVO4:Eu3+ NPs in the SiO2 matrix. N2 adsorption/desorption analysis confirms the mesoporous nature of the MSNs and YVO4:Eu3+-MSNs. No significant quenching of the YVO4:Eu3+ luminescence is observed for YVO4:Eu3+-MSNs. This nanocomposite has been tested as a potential drug carrier. Efficient loading of doxorubicin hydrochloride (DOX), a typical anticancer drug, is observed which reaches up to 93% in 8 mg ml−1 of YVO4:Eu3+-MSNs. pH sensitive release of DOX is observed, with 54% release for pH 4.3 and 31% in a physiological environment (pH 7.4). Both MSNs and YVO4:Eu3+-MSNs nanocomposites do not show accountable toxicity to two cell lines, i.e. HeLa and MCF-7. However, as desired, toxicity is observed when cells are incubated with DOX loaded YVO4:Eu3+-MSNs. Laser scanning confocal microscopy images confirm the uptake of the nanocomposite in both cell lines. The morphology of the cells (MCF-7) changes after incubation with DOX loaded YVO4:Eu3+-MSNs, indicating an interaction of DOX with the cells. More cytotoxicity to both cell lines with ∼90% killing is observed due to the synergistic effect of magnetic fluid hyperthermia and chemotherapy using a biphasic suspension of superparamagnetic iron oxide magnetic nanoparticles and DOX loaded YVO4:Eu3+-MSNs. In addition, an AC magnetic field triggers an enhanced drug release. (paper)

  7. Short and long term biosorption of silica-coated iron oxide nanoparticles in heterotrophic biofilms.

    Herrling, Maria P; Lackner, Susanne; Tatti, Oleg; Guthausen, Gisela; Delay, Markus; Franzreb, Matthias; Horn, Harald

    2016-02-15

    The increased application of engineered nanoparticles (ENP) in industrial processes and consumer products has raised concerns about their impact on health and environmental safety. When ENP enter the global water cycle by e.g. wastewater streams, wastewater treatment plants (WWTP) represent potential sinks for ENP. During biological WWT, the attachment of ENP to biofilms is responsible for the desired removal of ENP from the water phase avoiding their release into the aquatic environment. However, the fundamental mechanisms guiding the interactions between ENP and biofilms are not yet fully understood. Therefore, this study investigates the behavior and biosorption of inorganic ENP, here magnetic iron oxide nanoparticles coated with silica (scFe3O4-NP), with heterotrophic biofilms at different time scales. Their magnetic properties enable to follow scFe3O4-NP in the biofilm system by a magnetic susceptibility balance and magnetic resonance imaging. Biofilms were exposed to scFe3O4-NP at short contact times (5 min) in flow cells and complementary, scFe3O4-NP were introduced into a moving bed biofilm reactor (MBBR) to be observed for 27 d. Mass balances revealed that scFe3O4-NP sorbed to the biofilm within a few minutes, but that the total biosorption was rather low (3.2 μg Fe/mg TSS). scFe3O4-NP mainly sorbed to the biofilm surface inducing the detachment of outer biofilm parts starting after an exposure time of 3h in the MBBR. The biosorption depended on the exposure concentration of scFe3O4-NP, but less on the contact time. Most scFe3O4-NP exited the flow cell (up to 65%) and the MBBR (57%) via the effluent. This effect was favored by the stabilization of scFe3O4-NP in the bulk liquid by organic matter leading to a low retention capacity of the MBBR system. The results contribute to improve our understanding about the fate of ENP in environmental and in technical biofilm systems and give indications for future investigations needed. PMID:26674701

  8. Acute Phase Pulmonary Responses to a Single Intratracheal Spray Instillation of Magnetite (Fe3O4) Nanoparticles in Fischer 344 Rats

    Tada, Yukie; Yano, Norio; Takahashi, Hiroshi; Yuzawa, Katsuhiro; Ando, Hiroshi; Kubo, Yoshikazu; Nagasawa, Akemichi; Ogata, Akio; Nakae, Dai

    2012-01-01

    Iron nanomaterials are of considerable interest for application to nanotechnology-related fields including environmental catalysis, biomedical imaging, drug delivery and hyperthermia, because of their superparamagnetic characteristics and high catalytic abilities. However, information about potential risks of iron nanomaterials is limited. The present study assessed pulmonary responses to a single intratracheal spray instillation of triiron tetraoxide nanoparticles (magnetite) in rats. Ten-week-old male and female Fischer 344 rats (n=5/group) were exposed to a single intratracheal spray instillation of 0 (vehicle), 5.0, 15.0 or 45.0 mg/kg body weight (BW) of magnetite. After 14 days, the rats were sacrificed, and biological consequences were investigated. The lung weights of the 15.0 and 45.0 mg/kg BW male and female groups were significantly higher than those of the control groups. The lungs of treated rats showed enlargement and black patches originating from the color of magnetite. The typical histopathological changes in the lungs of the treated rats included infiltration of macrophages phagocytosing magnetite, inflammatory cell infiltration, granuloma formation and an increase of goblet cells in the bronchial epithelium. The results clearly show that instilled magnetite causes foreign body inflammatory and granulating lesions in the lung. These pulmonary responses occur in a dose-dependent manner in association with the increase in lung weight. PMID:23345925

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

    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

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

    Po-Jung Huang

    2015-01-01

    Full Text Available Cellulase from Aspergillus niger was immobilized onto β-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.

  11. Manipulating cluster size of polyanion-stabilized Fe3O4 magnetic nanoparticle clusters via electrostatic-mediated assembly for tunable magnetophoresis behavior

    We report in this article an approach for manipulating the size of magnetic nanoparticle clusters (MNCs) via electrostatic-mediated assembly technique using an electrolyte as a clustering agent. The clusters were surface-tethered with poly(sodium 4-styrenesulfonate) (PSS) through electrostatic compensation to enhance their colloidal stability. Dynamic light scattering was employed to trace the evolution of cluster size. Simultaneously, electrophoretic mobility and Fourier transform infrared spectroscopy analyses were conducted to investigate the possible schemes involved in both cluster formation and PSS grafting. Results showed that the average hydrodynamic cluster size of the PSS/MNCs and their corresponding size distributions were successfully shifted by means of manipulating the suspension pH, the ionic nature of the electrolyte, and the electrolyte concentration. More specifically, the electrokinetic behavior of the particles upon interaction with the electrolyte plays a profound role in the formation of the PSS/MNCs. Nonetheless, the solubility of the polymer in electrolyte solution and the purification of the particles from residual ions should not be omitted in determining the effectiveness of this clustering approach. The PSS adlayer makes the resultant entities highly water-dispersible and provides electrosteric stabilization to shield the PSS/MNCs from aggregation. In this study, the experimental observations were analyzed and discussed on the basis of existing fundamental colloidal theories. The strategy of cluster size manipulation proposed here is simple and convenient to implement. Furthermore, manipulating the size of the MNCs also facilitates the tuning of magnetophoresis kinetics on exposure to low magnetic field gradient, which makes this nano-entity useful for engineering applications, specifically in separation processes.

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

    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. Synthesis and characterization of Fe 3 O 4 @C@Ag nanocomposites and their antibacterial performance

    Xia, Haiqing; Cui, Bin; Zhou, Junhong; Zhang, Lulu; Zhang, Ji; Guo, Xiaohui; Guo, Huilin

    2011-09-01

    We synthesized Fe 3O 4@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 Fe 3O 4@Ag nanocomposites, the Fe 3O 4@C@Ag nanocomposites showed enhanced antibacterial activity. The Fe 3O 4@C@Ag nanocomposites were able to almost entirely prevent growth of Escherichia coli when the concentration of Ag nanoparticles was 10 μg/mL. Antibacterial activity of the Fe 3O 4@C@Ag nanocomposites was maintained for more than 40 h at 37 °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 Fe 3O 4@C@Ag nanocomposites will have potential uses in many fields as catalysts, absorbents, and bifunctional magnetic-optical materials.

  14. Removal of Cr(VIin water by Fe3O4/IP6

    CHEN Lu

    2014-12-01

    Full Text Available The preparation of functional ferroferric oxide (Fe3O4 magnetic nanoparticles is widely concerned.However,during their preparation,it is difficult to control the morphology of Fe3O4 nanoparticles and also a serious agglomeration exists,greatly restricting their applications.In present paper,an economical and ′green′ reagent-phytic acid (IP6 can form micelle in the water and then the nanoparticles can grow in a soft template.The as-prepared Fe3O4/IP6 exhibited a good stability and high dispersion.Fe3O4/IP6 can chelate with Cr (VI due to its phosphate structure.The Fe3O4/IP6 chelated with Cr (VI can be removed conveniently from water using an external magnet.Fe3O4/IP6 nanocomposites have a good adsorption capacity to Cr (VI within a short time (10 min.Additionally,the effect of pH on adsorption efficiency was studied.

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

    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 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

  16. Solid phase extraction of Cd(II) and Pb(II) ions based on a novel functionalized Fe3O4@ SiO2 core-shell nanoparticles with the aid of multivariate optimization methodology.

    Tadjarodi, Azadeh; Abbaszadeh, Abolfazl; Taghizadeh, Mohsen; Shekari, Nafiseh; Asgharinezhad, Ali Akbar

    2015-04-01

    This work describes novel Fe3O4@SiO2 core-shell nanoparticles functionalized with phenyl isothiocyanate and its application in the preconcentration of Cd(II) and Pb(II) ions. The parameters affecting the preconcentration procedure were optimized by a Box-Behnken design through response surface methodology. Three variables (extraction time, magnetic sorbent amount, and pH value) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent; and elution time) were selected as effective factors of elution step in the optimization study. Following the sorption and elution, the ions were quantified by FAAS. The limits of detection were 0.05 and 0.9ngmL(-1) for Cd(II) and Pb(II) ions, respectively. The relative standard deviations were less than 6.4%. The sorption capacity (in mg g(-1)) of this new sorbent is 179 for Cd(II) and 156 for Pb(II). Finally, this nanocomposite was successfully applied to the rapid extraction of trace quantities of heavy metal ions from fish, sediment, soil, and water samples and satisfactory results were obtained. PMID:25686967

  17. Solid phase extraction of antidepressant drugs amitriptyline and nortriptyline from plasma samples using core-shell nanoparticles of the type Fe3O4-ZrO2-N- cetylpyridinium, and their subsequent determination by HPLC with UV detection

    The solid phase extraction (SPE) is described for preconcentration of the antidepressant drugs amitriptyline and nortriptyline prior to their determination by HPLC with UV detection. It is based on the use of water-dispersible core-shell nanoparticles (NPs) of the Fe3O4-ZrO2-N-cetylpyridinium type. The positively charged surfactant N-cetylpyridinium forms mixed aggregates with the drugs on the surface of the core-shell and thereby improves the adsorption of amitriptyline and nortriptyline through hydrophobic and/or ionic interactions. Their extraction depends on the type and amount of surfactant, sample pH, extraction time, desorption conditions, sample volume and amount of NPs that were optimized by application of experimental design. The enrichment factors are 220 and 250, respectively, for amitriptyline and nortriptyline, and the detection limits are 0.04 and 0.08 ng·mL-1. This protocol enables accurate and precise quantification of the two drugs in complex and low content samples. It was applied to the determination of the two drugs in plasma samples with relative recoveries in the range from 89 to 105 % and RSDs less than 4 %. (author)

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

    Lan, Fang; Liu, Ke-Xia; Jiang, Wen; Zeng, Xiao-Bo; Wu, Yao; Gu, Zhong-Wei

    2011-06-01

    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.

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

    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.

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

    Lan, Fang; Liu, Ke-Xia; Jiang, Wen; Zeng, Xiao-Bo; Wu, Yao; Gu, Zhong-Wei

    2011-06-01

    Monodisperse superparamagnetic Fe(3)O(4)/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 Fe(3)O(4)/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 Fe(3)O(4)/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 Fe(3)O(4) nanoparticles. VSM and TGA showed that the Fe(3)O(4)/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 Fe(3)O(4) nanoparticles. PMID:21454944

  1. Magnetically separable mesoporous Fe3O4/silica catalysts with very low Fe3O4 content

    Grau-Atienza, A.; Serrano, E.; Linares, N.; Svedlindh, P.; Seisenbaeva, G.; García-Martínez, J.

    2016-05-01

    Two magnetically separable Fe3O4/SiO2 (aerogel and MSU-X) composites with very low Fe3O4 content (silica supports, leading to magnetic composites that can be easily recovered using an external magnetic field, despite their very low Fe3O4 NPs content (ca. 1 wt%). These novel hybrid Fe3O4/SiO2 materials have been tested for the oxidation reaction of 3,3‧,5,5‧-tetramethylbenzidine (TMB) with hydrogen peroxide showing an enhancement of the stability of the NPs in the Fe3O4/silica aerogel as compared to the Fe3O4 NPs alone, even after five catalytic cycles, no leaching or agglomeration of the Fe3O4/SiO2 systems.

  2. Magnetic Control of Fe3O4 Nanomaterial for Fat Ablation in Microchannel

    Ming Chang

    2015-11-01

    Full Text Available In this study, surface modification of iron (II, III oxide Fe3O4 nanoparticles by oleic acid (OA coating is investigated for the microablation of fat in a microchannel. The nanoparticles are synthesized by the co-precipitation method and then dispersed in organic solvent prior to mixing with the OA. The magnetization, agglomeration, and particle size distribution properties of the OA-coated Fe3O4 nanoparticles are characterized. The surface modification of the Fe3O4 nanoparticles reveals that upon injection into a microchannel, the lipophilicity of the OA coating influences the movement of the nanoparticles across an oil-phase barrier. The motion of the nanoparticles is controlled using an AC magnetic field to induce magnetic torque and a static gradient field to control linear translation. The fat microablation process in a microchannel is demonstrated using an oscillating driving field of less than 1200 Am−1.

  3. Novel method of room temperature ionic liquid assisted Fe3O4 nanocubes and nanoflakes synthesis

    Graphical abstract: - Highlights: • First time [Bmim][TfO] IL is used for the Fe3O4 nanoparticle synthesis. • Novel method tunes Fe3O4 nanocubes and nanoflakes forms influenced by the base and IL. • Fe3O4 oxidized topotactically into γ-Fe2O3 nanoparticles by annealing and base. • Uniform morphology with average size of 33 nm negligible superstructure are formed. • Ms values are characterized by thin layer of γ-Fe2O3 on the nanoparticle surface. - Abstract: For the first time, the nanomagnetite superparamagnetic particles are successfully synthesized by precipitation method using 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim][TfO] ionic liquid medium/surfactant. The obtained Fe3O4 particles are nanocubes and nanoflakes and this formation is influenced by the base concentration and anisotropic circumstances produced by the ionic liquid and their size varies from 20 nm to 150 × 300 nm (width × length). The synthesized magnetite nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) studies. The results show that the core of the Fe3O4 nanoparticles is surrounded by a thin layer of γ-Fe2O3 by topotactical partial oxidation, which is remarkably proceed with the subsequent calcination. The magnetite nanocubes have high saturation magnetization value and exhibit superparamagnetic hysteresis loop

  4. Structure and electrochemical performance of Fe3O4/graphene nanocomposite as anode material for lithium-ion batteries

    Highlights: → Fe3O4 nanoparticles dispersed homogeneously on graphene nanosheets were synthesized by hydrothermal route. → The Fe3O4/graphene nanocomposite as the anode material for lithium ion batteries showed a high reversible specific capacity of 771 mAh g-1 during up to 50 cycles and good rate capability. → The simple and low-cost method provides a potential approach for fabricating other graphene based materials. - Abstract: Using hydrothermal method, Fe3O4/graphene nanocomposite is prepared by synthesizing Fe3O4 particles in graphene. The synthesized Fe3O4 is nano-sized sphere particles (100-200 nm) and uniformly distributed on the planes of graphene. Fe3O4/graphene nanocomposite as anode material for lithium ion batteries shows high reversible specific capacity of 771 mAh g-1 at 50th cycle and good rate capability. The excellent electrochemical performance of the nanocomposite can be attributed to the high surface area and good electronic conductivity of graphene. Due to the high surface area, graphene can prevent Fe3O4 nanoparticles from aggregating and provide enough space to buffer the volume change during the Li insertion/extraction processes in Fe3O4 nanoparticles.

  5. Magnetic composite nanofibers fabricated by electrospinning of Fe3O4/gelatin aqueous solutions

    Graphical abstract: Superparamagnetic Fe3O4/GE composite nanofibers with saturation magnetization of 12.87 emμ g−1 were prepared from gelatin aqueous solution at an elevated temperature by electrospinning. - Highlights: • Electrospinning GE aqueous solution at higher temperature. • Presenting a simple and effective technique, combining wet blending with high temperature electrospinning to prepare magnetic composite nanofibers. • Developing composite nanofibers with higher superparamagnetic properties is expected to be useful in application for the biomedical field. - Abstract: We have fabricated magnetic composite nanofibers containing superparamagnetic Fe3O4 nanoparticles by the electrospinning method. Highly dispersed Fe3O4 magnetic nanoparticles were synthesized by one-step co-precipitation of Fe2+/Fe3+ under an alkaline condition with 4 wt% poly(vinyl alcohol) (PVA) aqueous solution as the stabilizer. Gelatin (GE) was used as a polymeric matrix for fabricating the nanocomposites. The prepared Fe3O4/GE composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), respectively. These composite nanofibers show uniform and continuous morphology with the Fe3O4 nanoparticles embedded in the nanofibers. By studying the magnetic properties of the Fe3O4/GE composite nanofibers, we confirm that the composite nanofibers possess superparamagnetic properties with a high saturated magnetization (Ms = 12.87 emμ g−1) at room temperature. The features of this approach for getting one-dimensional magnetic nanostructure are its simplicity, effectiveness and safety. The Fe3O4/GE nanofibers with superparamagnetic properties would be potentially applied in biomedical field

  6. Controlled synthesis and size-dependent thermal conductivity of Fe3O4 magnetic nanofluids.

    Wang, Baodui; Wang, Baogang; Wei, Pengfei; Wang, Xiaobo; Lou, Wenjing

    2012-01-21

    The effect of nanoparticle size (4~44 nm) on the thermal conductivities of heat transfer oils has been systematically examined using iron oxide nanoparticles. Such Fe(3)O(4) nanoparticles were synthesized by a simple one-pot pyrolysis method. The size (16~44 nm), shape and assembly patterns of monodisperse Fe(3)O(4) nanoparticles were modulated by only controlling the amount of Fe(acac)(3). After the as-prepared Fe(3)O(4) NPs were dispersed in heat transfer oils, the prepared magnetic nanofluids exhibit higher thermal conductivity than heat transfer oils, and the enhanced values increase with a decrease in particle size. In addition, the viscosities of all nanofliuids are remarkably lower than that of the base fluid, which has been found for the first time in the nanofluid field. The promising features offer potential application in thermal energy engineering. PMID:22086086

  7. Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness

    Gu, Shu-Ying; Jin, Sheng-Peng; Gao, Xie-Feng; Mu, Jian

    2016-05-01

    Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness are presented. For the purpose of fast response and homogeneous dispersion of magnetic nanoparticles, oleic acid was used to improve the dispersibility of Fe3O4 nanoparticles in a polymer matrix. A homogeneous distribution of Fe3O4 nanoparticles in the polymer matrix was obtained for nanocomposites with low Fe3O4 loading content. A small agglomeration was observed for nanocomposites with 6 wt% and 9 wt% loading content, leading to a small decline in the mechanical properties. PLAU and its nanocomposites have glass transition around 52 °C, which can be used as the triggering temperature. PLAU and its nanocomposites have shape fixity ratios above 99%, shape recovery ratios above 82% for the first cycle and shape recovery ratios above 91% for the second cycle. PLAU and its nanocomposites also exhibit a fast water bath or magnetic responsiveness. The magnetic recovery time decreases with an increase in the loading content of Fe3O4 nanoparticles due to an improvement in heating performance for increased weight percentage of fillers. The nanocomposites have fast responses in an alternating magnetic field and have potential application in biomedical areas such as intravascular stent.

  8. Spin-dependent transport properties of Fe3O4/MoS2/Fe3O4 junctions

    Wu, Han-Chun; Coileáin, Cormac Ó.; Abid, Mourad; Mauit, Ozhet; Syrlybekov, Askar; Khalid, Abbas; Xu, Hongjun; Gatensby, Riley; Jing Wang, Jing; Liu, Huajun; Yang, Li; Duesberg, Georg S.; Zhang, Hong-Zhou; Abid, Mohamed; Shvets, Igor V.

    2015-11-01

    Magnetite is a half-metal with a high Curie temperature of 858 K, making it a promising candidate for magnetic tunnel junctions (MTJs). Yet, initial efforts to exploit its half metallic nature in Fe3O4/MgO/Fe3O4 MTJ structures have been far from promising. Finding suitable barrier layer materials, which keep the half metallic nature of Fe3O4 at the interface between Fe3O4 layers and barrier layer, is one of main challenges in this field. Two-dimensional (2D) materials may be good candidates for this purpose. Molybdenum disulfide (MoS2) is a transition metal dichalcogenide (TMD) semiconductor with distinctive electronic, optical, and catalytic properties. Here, we show based on the first principle calculations that Fe3O4 keeps a nearly fully spin polarized electron band at the interface between MoS2 and Fe3O4. We also present the first attempt to fabricate the Fe3O4/MoS2/Fe3O4 MTJs. A clear tunneling magnetoresistance (TMR) signal was observed below 200 K. Thus, our experimental and theoretical studies indicate that MoS2 can be a good barrier material for Fe3O4 based MTJs. Our calculations also indicate that junctions incorporating monolayer or bilayer MoS2 are metallic.

  9. Mössbauer study of stability and growth confinement of magnetic Fe3O4 drug carrier

    Bare Fe3O4 and Fe3O4/zeolite composites have been investigated by Mössbauer spectroscopy. A confined growth of the nanoparticles has been observed after introduction of zeolite in the process of precipitation. Increase in the concentration of zeolite further decrease the particle size. A comparative study on the synthesis with zeolites 13x and ZSM5 has been done. Annealing on these nanoparticles shows that apart from the confinement of nanoparticles, zeolite enhances stability on the nanoparticles

  10. Core-Shell Nanostructure of α-Fe2O3/Fe3O4: Synthesis and Photocatalysis for Methyl Orange

    Yang Tian

    2011-01-01

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

  11. 超声乳化法制备纳米Fe3O4磁性颗粒及壳聚糖表面改性%Preparation of Fe3 04 magnetic nanoparticles by ultrasonic emulsification and research of magnetic fluids with chitosan modification

    季业; 邵慧萍; 郭志猛; 林涛; 杨栋华

    2011-01-01

    Fe3O4 magnetic nanopartieles were prepared by means of ultrasonic emulsification and then the Fe304 magnetic fluid was made by dispersing these particles into water with chitosan as surfactants. The influences of the molar ratio of Fe2+ to Fe3 + , ultrasonic time and the amount of chitosan on the magnetic properties of the magnetic fluid were investigated. The results show that ideal Fe3 O4 magnetic nanoparticles can be obtained under the condition that the molar ratio of Fe2 + to Fe3 + is 1: 1.5 and the reaction temperature is 70 ℃ when dropping ammonia. The prepared magnetic fluid has high specific saturation magnetization and stability when the volume of the 1% chitosan solution is 50% as large as the total volume of the mixed Fe3O4 solution and the ultrasonic time after dropping chitosan is 7.5 min, which are in favor of coating the magnetic particles with chitosan.%采用超声乳化法制备纳米Fe3O4磁性颗粒,以壳聚糖作为表面活性剂,制备具有生物亲和性的水基Fe3O4磁流体.研究了Fe2+/Fe3摩尔比、超声时间和表面活性剂用量对磁流体性能的影响.结果表明:当Fe2+/Fe3+摩尔比为1:1.5,滴加氨水时反应温度为70℃时,可制备理想纳米Fe3O4磁性颗粒;超声时间为7.5 min左右,质量分数1%的壳聚糖溶液体积占Fe3O4溶液总体积的50%时,有利于壳聚糖分子的包覆,使磁流体具有较高的比饱和磁化强度及稳定性.

  12. Magnetic heating of silica-coated manganese ferrite nanoparticles

    Iqbal, Yousaf; Bae, Hongsub; Rhee, Ilsu; Hong, Sungwook

    2016-07-01

    Manganese ferrite nanoparticles were synthesized using the reverse micelle method; these particles were then coated with silica. The silica-coated nanoparticles were spherical in shape, with an average diameter of 14 nm. The inverse spinel crystalline structure was observed through X-ray diffraction patterns. The coating status of silica on the surface of the nanoparticles was confirmed with a Fourier transform infrared spectrometer. The superparamagnetic properties were revealed by the zero coercive force in the hysteresis curve. Controllable heating at a fixed temperature of 42 °C was achieved by changing either the concentration of nanoparticles in the aqueous solution or the intensity of the alternating magnetic field. We found that at a fixed field strength of 5.5 kA/m, the 2.6 mg/ml sample showed a saturation temperature of 42 °C for magnetic hyperthermia. On the other hand, at a fixed concentration of 3.6 mg/ml, a field intensity of 4.57 kA/m satisfied the required temperature of 42 °C.

  13. Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

    Kurtan, U; Amir, Md; Baykal, A; Sözeri, H; Toprak, M S

    2016-03-01

    Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water. PMID:27455668

  14. Green synthesis and surface properties of Fe3O4@SA core-shell nanocomposites

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

    2014-05-01

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

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

    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

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

    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.

  17. Preparation and characterization of Fe3O4/Au composite particles

    CUI Yali; HUI Wenli; WANG Huirong; WANG Lijun; CHEN Chao

    2004-01-01

    Using Fe3O4 nano-particles as seeds, a new type of Fe3O4/Au composite particles with core/shell structure and diameter of about 170 nm was prepared by reduction of Au3+ with hydroxylamine in an aqueous solution. Particle size analyzer and transmission electron microscope were used to analyze the size distribution and microstructure of the particles in different conditions. The result showed that the magnetically responsive property and suspension stability of Fe3O4 seeds as well as reduction conditions of Au3+ to Au0 are the main factors which are crucial for obtaining a colloid of the Fe3O4/Au composite particles with uniform particle dispersion,excellent stability, homogeneity in particle sizes, and effective response to an external magnet in aqueous suspension solutions. UV-Vis analysis revealed that there is a characteristic peak of Fe3O4/Au fluid. For particles with d(0.5)=168 nm, the λmax is 625 nm.

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

    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.

  19. Studies on the synthesis and microwave absorption properties of Fe3 O4/polyaniline FGM

    Electrically conducting polyaniline (PANI)-magnetic oxide (Fe3 O4) composites were synthesized by emulsion polymerization in the presence of dodecyl benzene sulfonic acid (DBSA) as the surfactant and dopant and ammonium persulfate (APS) as the oxidant. Transmission electron microscopy (TEM) indicates that the composite has a magnetic core and an electric shell and the modification has prevented the aggregation of Fe3 O4 nanoparticles effectively. The electromagnetic parameter measurements (ε-prime, ε', μ-prime and μ') in the range of 2-18 GHz prove that Fe3 O4 in the Fe3 O4/PANI/DBSA is responsible for the electric and ferromagnetic behavior of the composites. As a result, the electromagnetic parameters can be designed by adjusting the content of the Fe3 O4. The microwave absorption of functionally graded material (FGM) was simulated by the computer according to the principle of impedance match and the calculated results agreed quite well with the experimentally measured data (R4 GHz)

  20. Reactively sputtered Fe3O4-based films for spintronics

    Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4-based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4-based heterostructures is considered to be caused by a shift of the Fe3O4 eg ↑ band near the interface. Enhanced magnetization was observed in Fe3O4/BiFeO3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface. (topical review - magnetism, magnetic materials and interdisciplinary research)

  1. Evaluation of the antibacterial activity of Ag/Fe3O4 nanocomposites synthesized using starch.

    Ghaseminezhad, Seyedeh Masumeh; Shojaosadati, Seyed Abbas

    2016-06-25

    Ag/Fe3O4 nanocomposites were successfully synthesized by a facile and cost-effective method using starch. Starch acts as both a biocompatible capping agent for Fe3O4 nanoparticles and a reducing agent for the reduction of silver ions in an alkaline medium. Samples were characterized using several analytical techniques including field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), and Fourier-transform infrared (FT-IR) spectroscopy. The vibrating sample magnetometer revealed that the nanocomposites were superparamagnetic. The Ag/Fe3O4 nanocomposites demonstrated a high-antibacterial activity against Escherichia coli as evaluated by means of minimum inhibitory concentration. The characteristics and antibacterial activity of the nanocomposites were significantly influenced by the concentration of silver nitrate and pH. PMID:27083838

  2. Mechanistic studies of magnetically recyclable Pd - Fe3O4 heterodimeric nanocrystal-catalyzed organic reactions.

    Byun, Sangmoon; Chung, Jooyoung; Kwon, Jungmin; Moon Kim, B

    2015-04-01

    Recently, we have reported several catalytic applications of new Pd - Fe3 O4 heterodimeric nanocrystals as magnetically separable catalysts. Successful applications of the nanocrystals towards various useful organic reactions such as Suzuki, Heck, and Sonogashira coupling reactions, direct C - H arylation, and Wacker oxidation have been recorded. However, detailed mechanistic courses of the reactions have not been delineated, and it was not clear whether these processes proceeded through a homogeneous or heterogeneous mechanism. Here, we report detailed mechanistic investigations of the reactions employing the Pd - Fe3 O4 nanoparticle catalysts. Suzuki coupling and Wacker oxidation reactions were chosen as two representative heterogeneous reactions employing the Pd - Fe3 O4 catalysts, and general kinetic studies, hot filtration tests, and three-phase tests were carried out for the two reactions. The studies showed that the reactions most probably proceed via a solution-phase mechanism. PMID:25620124

  3. Analysis of surface potential and magnetic properties of Fe3O4/graphene oxide nanocomposites

    Mishra, Amodini; Mohanty, Tanuja

    2016-05-01

    Nanocomposite of magnetite/graphene oxide (Fe3O4/GO) has been synthesized by co-precipitation method. The phase formation of the magnetite nanoparticles (Fe3O4 NPs) was confirmed by X-ray diffraction (XRD) analysis. Effect of Fe3O4 NPs on the Raman spectra and on the surface potential of GO has been analyzed. Due to incorporation of NPs, change in the characteristic Raman peaks and also on the surface potential of GO is observed. Transmission electron microscopic (TEM) study has been carried out for surface morphology. Magnetic property measurement was carried out by using physical property measurement system (PPMS) at two different temperatures (30 K and 300K).

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

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

    2009-11-01

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

  5. Hydrothermal growth of octahedral Fe 3O4crystals

    Dengfeng Peng; Sadeh Beysen; Qiang Li; Jikang Jian; Yanfei Sun; Jilili Jiwuer

    2009-01-01

    This paper reports the growth of octahedral magnetic Fe3O4 particles from iron powders via a simple alkaline hydrothermal process. The chemical compositions and morphologies of the as-grown Fe3O4 particles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), and scanning electron microscopy (SEM). Structure characterization showed that the phase structure of the prepared particles evolved from α-Fe to pure Fe3O4 with increasing concentration of KOH, indicating the important role of KOH concentration on the formation of the magnetite octahedron. The magnetic properties of samples were also studied by means of a vibrating sample magnetometer (VSM). The pure magnetite Fe3O4 octahedrons exhibited a relatively high saturation magnetization of 96.7 emu/g.

  6. Preparation and Characterization of Solvent-free Fe3O4 Nanofluids%无溶剂Fe3O4纳米流体的制备及表征

    檀雨默; 郑亚萍; 兰岚

    2012-01-01

    采用共沉淀法合成Fe3O4纳米粒子,将含有硅氧烷基的离子型改性剂二甲基十八烷基[3-(三甲氧基硅基)丙基]氯化铵与Fe3O4纳米粒子进行接枝反应,再用脂肪醇聚氧乙烯醚磺酸盐的长链阴离子交换C1-,在Fe3O4纳米粒子表面生成具有阴、阳离子双电层结构的表面处理层,得到无溶剂Fe3O4纳米流体.研究结果表明,在Fe3O4纳米粒子表面成功接枝了有机物长链,改性的Fe3O4纳米粒子呈单分散分布,其损耗剪切模量G″明显大于储能剪切模量G',具有明显的流体行为,在室温下即可流动.%The surfactant was used to functionalize the nanoparticles to prepare solvent-free nanofluids. To prevent Fe3O4 nanoparticles from agglomerating and improve the dispersion of Fe3O4 nanoparticles, the solvent-free Fe3O4 nanofluids were synthesized through surface modification. Magnetic Fe3O4 nanoparticles were firstly prepared by chemical co-precipitation method. Then graft the quaternary ammonium salt (CH3O)3Si(CH2)3N+(CH3)2(C18Hj7)C1-, which has silanol groups, on Fe3O4 nanoparticles with hydroxyl groups. Finally, the chloridion was replaced with the anion C9H19-C6H4(OCH2CH2)200(0112)3503 through an ion-exchang process. An organic layer was formed on the surface of Fe3O4 nanoparticles, and made the Fe3O4 nanoparticles from black powder to brown fluid ( at room temperature). The solvent-free Fe3O4 nanofluids were characterized by X-ray diffraction, Fourier transform infrared spectrum, differential scanning calorimetry, thermogravimetric analysis, transmission electron microscopy and rheometer. The Fe3O4 nanoparticles were monodispersed in solvent-free nanofluids, and the content of Fe3O4 nanoparticles in the nanofluids proved to be about 12%. The loss shear modulus G" was higher than the storage shear modulus G1.

  7. Influence of PVP on solvothermal synthesized Fe3O4/graphene composites as anodes for lithium-ion batteries

    Fe3O4/graphene composites have been prepared through a facile solvothermal process. Influence of PVP on the structure, morphologies, and electrochemical properties of composites were detected by means of X-ray diffraction, FT-IR spectra, Raman spectroscopy, scanning electron microscope, transmission electron microscopy, and electrochemical measurements. The results showed that Fe3O4 microspheres were dispersed and anchored on graphene nanosheets. The Fe3O4 microspheres are composed of nanoparticles and exhibit the interstitial cluster structure. The average size of Fe3O4 microspheres with introduction of PVP is smaller than that without PVP. As anodes materials for lithium-ion batteries, Fe3O4/G-PVP electrode exhibits better rate performance and higher capacities compared with Fe3O4/G electrode. Fe3O4/G-PVP can deliver an initial discharge capacity of 850.4 mA h g-1 and a high capacity of 400 mA h g-1 after 300 cycles at a current density of 1300 mA g-1. (author)

  8. Fabrication of magnetically recyclable Fe3O4@Cu nanocomposites with high catalytic performance for the reduction of organic dyes and 4-nitrophenol

    A facile and efficient approach to synthesize Fe3O4@Cu nanocomposites using L-Lysine as a linker was developed. The morphology, composition and crystallinity of the Fe3O4@Cu nanocomposites were characterized by Fourier Transform infrared spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and powder X-ray diffraction. In addition, the magnetic properties were determined with vibrating sample magnetometer. The surface of the Fe3O4 contained many small Cu nanoparticles with sizes of about 3 nm. It was found that the Fe3O4@Cu nanocomposites could catalyze the degradation of organic dyes. The catalytic activities of the Fe3O4@Cu nanocomposites for the reduction of nitrophenol were also studied. The Fe3O4@Cu nanocomposites are more efficient catalysts compared with Cu nanoparticles and can easily be recovered from the reaction mixture with magnet. The cost effective and recyclable Fe3O4@Cu nanocomposites provide an exciting new material for environmental protection applications. - Highlights: • Cu nanoparticles as small as 3 nm are synthesized. • Low cost Fe3O4@Cu magnetical nanoparticles show catalytic activity for organic dyes and 4-nitrophenol. • The Fe3O4@Cu display high catalytic activity after 13 cycles

  9. Superparamagnetic Fe3O4/Poly(N-isopropyl acrylamide) Nanocomposites Synthesized in Inverse Miniemulsions: Magnetic and Particle Properties.

    Cui, Qinmin; Zhu, Shudi; Yan, Yingjie; Ye, Quanlin; Ziener, Ulrich; Cao, Zhihai

    2015-06-01

    In the present study, superparamagnetic Fe3O4/poly(N-isopropyl acrylamide) nanocomposites were synthesized by one-step inverse miniemulsion copolymerization of N-isopropyl acrylamide and N,N'-methylene diacrylamide. The loading of Fe3O4 nanoparticles in the nanocomposites was 27 wt%, and the saturation moment of the nanocomposites was 12.4 emu x g(-1). Fe3O4 nanoparticles were prepared through a coprecipitation method. The amount of stabilizer (poly(acrylic acid)) significantly influenced the size and size distribution of the Fe3O4 nanoparticles, and, therefore, their magnetic properties. Superparamagnetism of the Fe3O4 nanoparticles was preserved in the nanocomposites. The effects of synthetic parameters on the particle properties, namely surfactant loading, concentration of ferrofluid, type of lipophobe and initiator, and amount of cross-linker were investigated. Nanocomposites of Fe3O4/poly(N-isopropyl acrylamide) displayed a guava-like morphology, which they could retain after being redispersed in polar solvents. PMID:26369088

  10. Photodegradation of Methylene Blue by TiO2-Fe3O4-Bentonite Magnetic Nanocomposite

    Wei Chen

    2015-01-01

    Full Text Available Fe3O4-bentonite nanoparticles have been prepared by a coprecipitation technique under a nitrogen atmosphere. An aqueous suspension of bentonite was first modified with FeCl2 and FeCl3. TiO2 was then loaded onto the surface of the Fe3O4-bentonite by a sol-gel method. After sufficient drying, the colloidal solution was placed in a muffle furnace at 773 K to obtain the TiO2-Fe3O4-bentonite composite. The material has been characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD analysis, and vibrating sample magnetometry (VSM. Morphological observation showed that Fe3O4 and TiO2 nanoparticles had been adsorbed on the surface of bentonite nanoneedles. The material was then applied for the photodegradation of the azo dye methylene blue (MB. It was found that the removal efficiency of MB exceeded 90% under UV illumination, and that only a 20% mass loss was incurred after six cycles. The composite material thus showed good photocatalytic performance and recycling properties.

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

    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. - Highlights: • Chitosan polymers doped with Fe3O4 are prepared by the solution casting technique. • The structural, magnetic, and microwave absorption properties of the samples are analyzed. • The polymer behaves like a superparamagnetic material with high blocking temperature. • The effective magnetization shows gradual increments with the concentration of Fe3O4. • The microwave absorption characteristic shows low reflection loss

  12. Magnetorheological Payne effect in bidisperse MR fluids containing Fe nanorods and Fe3O4 nanospheres: a dynamic rheological study

    Arief, Injamamul; Mukhopadhyay, P. K.

    2015-01-01

    The spherical Fe3O4 with 300 nm in diameter was synthesized by typical thermal decomposition of Fe (III) organo-metallic precursor in polyol and polyacrylic acid. Fe-nanorods were prepared by reducing Fe (III) nitrate in presence of polyol-hydrazine-CTAB. Morphology and magnetic characterization of the nanoparticles were performed by ESEM, XRD and VSM studies. We performed detailed non-linear magnetorheological properties of three MR fluids (10 vol%) containing isotropic Fe3O4 and anisotropic...

  13. One-step preparation of Fe3O4/Pd@polypyrrole composites with enhanced catalytic activity and stability.

    Zhang, Hui; Liu, Yang; Wu, Jie; Xin, Baifu

    2016-08-15

    Core/shell Fe3O4/Pd@polypyrrole (PPy) composites with a Fe3O4 core and a PPy shell embedding Pd nanoparticles were prepared in one-step. The diameter of highly dispersed Pd nanoparticles was as small as 2.9nm owing to coordination interaction generated between Pd(2+) ions and amino groups on PPy chains. The outer PPy shell was only 6.8nm: on one hand, the coverage was beneficial to improving the stability of resulting composites; on the other hand, the shell was thin enough to permit free contact between embedding Pd nanoparticles and reactants. Additionally, the as-prepared Fe3O4/Pd@PPy composites displayed good magnetic separation property due to incorporation of Fe3O4 nanospheres. Based on above merits, they served as suitable catalyst candidates. Their catalytic performance and reusability were evaluated by reduction of 4-nitrophenol with sodium borohydride as reducing agent. Compared with traditional Fe3O4/Pd composites, Fe3O4/Pd@PPy composites not only showed superior catalytic activity; but also exhibited much better stability in successive cycling tests. PMID:27232537

  14. PREPARATION AND CHARACTERIZATION OF SLIGHTLY ALKALINE STABILIZED Fe3O4 WATER-BASED FERROFLUID%弱碱性稳定Fe3O4水基磁流体的制备与表征

    叶楠; 唐建成; 卓海鸥

    2013-01-01

    In the study, Fe3O4 magnetic nanoparticles were prepared by chemical co-precipitation method. The obtained magnetic nanoparticles were used to prepared water-based fer-rofluid after deionization with sodium oleate as surfactant. The samples have been characterized by XRD, FT-IR, SEM and VSM. The effects of pH value on the stability of ferrofluid were discussed. The results indicated that Fe3O4 nanoparticles were inverse cubic spinel phase with an average particle size of 18 nm. The double-coated structure of Fe3O4 nanoparticles were formed by sodium oleate and led to well dispersal of Fe3O4 nanoparticles in ferrofluid. The coated Fe3O4 nanoparticles exhibit superparamagnetism and lower saturation magnetization compared with the pure ones. The surface charge and coated effect of Fe3O4 nanoparticles varied with pH value, and then affected the stability of ferrofluid. The ferrofluid demonstrated excellent stability while the pH = 7. 5.%利用化学共沉淀法制备了纳米Fe3O4磁性微粒,去离子化处理后用油酸钠进行表面改性制备咸水基磁流体.分别用XRD、FT-IR、SEM和VSM等手段对样品进行表征,探讨了pH值对磁流体稳定性的影响.结果表明制备的Fe3O4磁性粒子为面心立方的反尖晶石结构,平均粒径在18 nm左右.磁流体中油酸钠在纳米Fe3O4粒子表面形成了双层包覆,改性后的纳米磁粒分散性良好,具有超顺磁性,饱和磁化强度较改性之前有所降低.体系的pH值可以改变Fe3O4磁性粒子的表面电荷和油酸钠的包覆效果,从而影响磁流体的稳定性,制备的磁流体在pH=7.5时具有良好的稳定性.

  15. Preparation and antibacterial activity of Fe3O4/Ag nanocomposites%Fe3O4/Ag复合纳米颗粒的制备及其抑菌性能研究

    武嘉培; 白俊杰; 李志鹏; 张栋顺; 范旭日

    2012-01-01

    We prepare Fe3O4 nanoparticles by solvothermal routes. We obtain Fe3O4/Ag nanocomposite with Fe3O4 nanoparticales as magnetic core, reaction with glucose in a high-temperture and high-pressure reactor and the coated nanoparticles reaction with AgNO3 by the reduction of chitosan. Their morphology and structure are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Determination of antibacterial test of minimal inhibitory concentration and minimum bactericidal concentration shows that composite materials Fe3O4/Ag have better antibacterial activity.%首先用水热法制备了Fe3O4纳米球,然后以制备的磁性Fe3O4纳米粒子为磁核,在高温高压反应釜中与葡萄糖反应,使其表面包覆一层聚糖,利用聚糖的还原性,让包覆后的粒子与AgNO3反应,制备出Fe3O4/Ag纳米复合粒子。用透射电镜(TEM)、X射线衍射仪(XRD)对所制备的材料的形貌和结构进行了表征。通过抑菌实验的测定,结果表明Fe3O4/Ag复合材料具有良好的抑菌活性。

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

    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.

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

    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

  18. Grape-Like Fe3O4 Agglomerates Grown on Graphene Nanosheets for Ultrafast and Stable Lithium Storage.

    Qi, Liya; Xin, Yuelong; Zuo, Zicheng; Yang, Chengkai; Wu, Kai; Wu, Bin; Zhou, Henghui

    2016-07-13

    An in situ simple and effective synthesis method is effectively exploited to construct MOF-derived grape-like architecture anchoring on nitrogen-doped graphene, in which ultrafine Fe3O4 nanoparticles are uniformly dispersed (Fe3O4@C/NG). In this hybrid hierarchical structure, new synergistic features are accessed. The graphene oxide plane with functional groups is expected to alleviate the aggregation problem in the MOFs' growth. Moreover, the morphology and size of iron-based MOFs and carbon content are conveniently controlled by controlling the solution concentration of precursor. Through making use of in situ carbonization of the organic ligands in MOFs, Fe3O4 subunits are effectively protected by 3D interconnected conductive carbon at microscale. Consequently, when applied as anode materials, even as high as 10 A g(-1) after 1000 cycles, Fe3O4@C/NG still maintains as high as 458 mA h g(-1). PMID:27311737

  19. Palladium-Fe3O4 nanoparticles fabricated biosensor for the detection of organophorus pesticide%钯-四氧化三铁纳米复合物生物传感器的制备及检测有机磷农药的研究

    李灿鹏; 杨龙; 庞芳; 杨周; 王光灿

    2013-01-01

    合成钯-四氧化三铁纳米粒子(Pd-Fe3O4 NPs)并制备了乙酰胆碱酯酶(AChE)电流型生物传感器用于检测有机磷杀虫剂.Pd-Fe3O4 NPs在电极与乙酰胆碱酯酶之间提供了一个具有较高电子传导性、较好生物相容性和较强催化活性的微环境,有效地提高了乙酰胆碱酯酶的生物活性和有机磷杀虫剂对乙酰胆碱酯酶的抑制作用.以对硫磷为有机磷杀虫剂模型分子,乙酰胆碱酶的抑制率与对硫磷浓度在5×10-12~1×10-9mol/L之间呈现良好的线性关系,检测限为2.5×10-12 mol/L.%Palladium-Fe3O4 nanoparticles ( Pd-Fe3O4 NPs) were synthesized and used for fabrication of acetylcholinesterase ( AChE ) amperometric biosensor for the detection of organophosphorus pesticises ( Ops).The Pd-Fe3O4 NPs provided a microenvironment which have high electronic conductivity, good biological consistent and strong catalytic activity between GCE and acetylcholinesterase ( AChE) , effectively enhanced AChE biological activity and organophosphates (OPs) to the AChE inhibitory action. Using parathion as a model of OPs, the inhibition of parathion was proportional to its concentration ranging from 5. 0×10-12mol/Land 1 × 10 -9mol/L, with a detection limit 2. 5×10 -12mol/L.

  20. Tribological Properties of Graphene-based Fe3O4 Nanocomposite Materials

    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.

  1. Synthesis of Fe3O4/Polyacrylonitrile Composite Electrospun Nanofiber Mat for Effective Adsorption of Tetracycline.

    Liu, Qing; Zhong, Lu-Bin; Zhao, Quan-Bao; Frear, Craig; Zheng, Yu-Ming

    2015-07-15

    Novel Fe3O4/polyacrylonitrile (PAN) composite nanofibers (NFs) were prepared by a simple two-step process, an electrospinning and solvothermal method. Characterization by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) demonstrated formation of a uniform nanoparticles coating (about 20 nm in thickness) on the PAN nanofiber backbone. The coating was constructed by well-crystallized cubic phase Fe3O4 nanoparticles as examined by X-ray diffraction spectroscopy (XRD). The coating doubled the specific surface area of NFs, from 8.4 to 17.8 m2 g(-1), as confirmed by nitrogen sorption isotherm analysis. To evaluate the feasibility of Fe3O4/PAN composite NFs as a potential adsorbent for antibiotic removal, batch adsorption experiments were conducted using tetracycline (TC) as the model antibiotic molecule. The results showed that Fe3O4/PAN composite NFs were effective in removing TC with no impactful loss of Fe in the pH regime of environmental interest (5-8). The adsorption of TC onto Fe3O4/PAN composite NFs better fitted the pseudo-second-order kinetics model, and the maximum adsorption capacity calculated from Langmuir isotherm model was 257.07 mg g(-1) at pH 6. The composite NFs also exhibited good regenerability over repeated adsorption/desorption cycles. Surface complexation between TC and the composite NFs contributed most to the adsorption as elucidated by X-ray photoelectron spectroscopy (XPS). This highly effective and novel adsorbent can be easily modularized and separated, promising its huge potential in drinking and wastewater treatment for antibiotic removal. PMID:26079116

  2. Green synthesis of the Cu/Fe3O4 nanoparticles using Morinda morindoides leaf aqueous extract: A highly efficient magnetically separable catalyst for the reduction of organic dyes in aqueous medium at room temperature

    Nasrollahzadeh, Mahmoud; Atarod, Monireh; Sajadi, S. Mohammad

    2016-02-01

    This paper reports the green and in-situ preparation of the Cu/Fe3O4 magnetic nanocatalyst synthesized using Morinda morindoides leaf extract without stabilizers or surfactants. The catalyst was characterized by XRD, SEM, EDS, UV-visible, TEM, VSM and TGA-DTA. The catalytic performance of the resulting nanocatalyst was examined for the reduction of 4-nitrophenol (4-NP), Congo red (CR) and Rhodamine B (RhB) in an environmental friendly medium at room temperature. The catalyst was recovered using an external magnet and reused several times without appreciable loss of its catalytic activity. In addition, the stability of the recycled catalyst has been proved by SEM and EDS techniques.

  3. A mild synthetic route to Fe3O4@TiO2-Au composites: preparation, characterization and photocatalytic activity

    Ma, Jianqi; Guo, Shaobo; Guo, Xiaohua; Ge, Hongguang

    2015-10-01

    To prevent and avoid magnetic loss caused by magnetite core phase transitions involved in high-temperature crystallization of sol-gel TiO2, a direct and feasible low-temperature crystallization technique was developed to deposit anatase TiO2 nanoparticle shell on Fe3O4 sphere cores. To promote the photocatalytic efficiency of the obtained core-shell Fe3O4@TiO2 magnetic photocatalyst, uniformly distributed Au nanoparticles (NPs) were successfully immobilized on the core-shell Fe3O4@TiO2 spheres via a seed-mediated growth procedure. The 3 nm Au colloid absorbed on Fe3O4@TiO2 served as a nucleation site for the growth of Au NPs overlayer. The morphology, structure, composition and magnetism of the resulting composites were characterized, and their photocatalytic activities were also evaluated. In comparison to Fe3O4@TiO2, Fe3O4@TiO2-Au exhibited higher photocatalytic activity for organic degradation under UV irradiation. This enhanced mechanism may have resulted from efficient charge separation of photogenerated electrons and holes due to the Au NPs attached on the TiO2. In addition, the composites possessed superparamagnetic properties with a high saturation magnetization of 44.6 emu g-1 and could be easily separated and recycled by a magnet.

  4. Preparation, magnetism and microwave absorption performance of ultra-thin Fe3O4/carbon nanotube sandwich buckypaper

    Graphical abstract: Fe3O4/multi-walled carbon nanotubes (MWCNTs) sandwich buckypapers were fabricated with monodispersion solutions of MWCNTs and Fe3O4 nanoparticles through layer by layer vacuum filtration method. The Fe3O4/MWCNTs sandwich buckypaper can be co-cured on the surface of fiber reinforce composites and exhibits excellent magnetism and microwave absorbing ability only with a 0.1 mm thickness absorbing layer. - Highlights: • Sandwich buckypapers were fabricated with MWCNTs/Fe3O4 monodispersions through vacuum filtration. • Composite with a 0.1 mm thickness sandwich buckypaper exhibits strong microwave absorbing ability. • The sandwich buckypaper has higher magnetic loss and suitable dielectric loss. • The sandwich buckypaper can fulfil the impedance matching and attenuation characteristics. - Abstract: Fe3O4/multi-walled carbon nanotubes (MWCNTs) sandwich buckypapers were fabricated with monodisperse solutions of MWCNTs and Fe3O4 nanoparticles through layer by layer vacuum filtration method and can be co-cured with composites for microwave absorbing application. The morphology, element composition and magnetic properties of sandwich buckypapers were characterized by field-emission scanning electron microscope, energy dispersive spectrometer, X-ray diffraction and vibrating sample magnetometer. The complex permittivity and permeability, the reflection loss properties of polymer composites surface coated buckypapers were investigated in the frequency range of 8.2–18 GHz. The results indicate that, due to the electromagnetic matching of magnetic loss and dielectric loss, the microwave absorption properties of the Fe3O4/MWCNTs sandwich buckypaper attached polymer composites are evidently improved. When the blending Fe3O4 content in sandwich buckypaper is 20 wt%, the composite displays a larger and wider absorption peak (−12.62 dB at 17.72 GHz), and the bandwidth of the reflection loss below −5 dB is larger than 5.6 GHz with a absorbing

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

    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...

  6. Preparation and application of magnetic Fe3O4 nano-particles%磁性纳米Fe3O4粒子的制备与应用

    张杰; 胡登华

    2011-01-01

    In order to summarize and review the preparation and application of magnetic Fe3O4 nano-particles, the preparation methods of magnetic Fe3O4 nano-particles was overviewed in this paper, including mechanical milling method, precipitation method, microemulsion method, solvothermal method, sol-gel method and pyrolysis method of organics. The advantages and disadvantages of each method were briefly analyzed. Applications of magnetic Fe3O4 nano-particles in ferrofluid, magnetic recording material, biomedicine, catalyst carrier and so on, were introduced. Finally, the focus and application prospect for magnetic Fe3O4 nano-particles in the future were predicted.%为了对磁性纳米Fe3O4颗粒的制备和应用进行总结和回顾,综述了磁性纳米Fe3O4颗粒的机械研磨法、沉淀法、微乳液法、溶剂热法、溶胶-凝胶法、热分解有机物法等几种主要制备方法,分析了各制备方法的特点;介绍了磁性纳米Fe3O4颗粒在磁流体、磁记录材料、生物医学以及催化剂载体等领域的应用,并对磁性纳米Fe3O4颗粒未来的研究重点和应用前景进行了展望:如何更经济更环保地制备粒径可控且分布均匀的磁性纳米Fe3O4微粒是今后研究的热点与重点;纳米Fe3O4颗粒同时具备磁性颗粒和纳米颗粒的双重优势的应用性研究也极为重要.

  7. Synthesis of magnetic porous Fe3O4/C/Cu2O composite as an excellent photo-Fenton catalyst under neutral condition.

    Chai, Fanfan; Li, Keyan; Song, Chunshan; Guo, Xinwen

    2016-08-01

    Magnetic porous Fe3O4/C/Cu2O composites were prepared by a simple two-step process. Porous Fe3O4/C was synthesized via calcining iron tartrate precursor and then Cu2O was composited with Fe3O4/C by a precipitation-reduction method. The as-prepared samples were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) elemental mapping. Results show that Fe3O4/C has porous nanorod structure, which is composed of numerous small nanoparticles of about 50nm. Fe3O4 and carbon are uniformly distributed in the Fe3O4/C/Cu2O composite and Cu2O is dispersed on the surface of Fe3O4/C. Fe3O4/C/Cu2O composite exhibits excellent photo-Fenton catalytic performance for the degradation of methylene blue (MB) under visible light irradiation and neutral pH conditions, and MB (100mg/L) could be almost completely removed within 60min. The composite shows good recyclability and could be conveniently separated by an applied magnetic field. These results demonstrate that the Fe3O4/C/Cu2O composite is a powerful Fenton-like catalyst for degradation of organic pollutants from wastewater. PMID:27161809

  8. Multifunctional pDNA-Conjugated Polycationic Au Nanorod-Coated Fe3 O4 Hierarchical Nanocomposites for Trimodal Imaging and Combined Photothermal/Gene Therapy.

    Hu, Yang; Zhou, Yiqiang; Zhao, Nana; Liu, Fusheng; Xu, Fu-Jian

    2016-05-01

    It is very desirable to design multifunctional nanocomposites for theranostic applications via flexible strategies. The synthesis of one new multifunctional polycationic Au nanorod (NR)-coated Fe3 O4 nanosphere (NS) hierarchical nanocomposite (Au@pDM/Fe3 O4 ) based on the ternary assemblies of negatively charged Fe3 O4 cores (Fe3 O4 -PDA), polycation-modified Au nanorods (Au NR-pDM), and polycations is proposed. For such nanocomposites, the combined near-infrared absorbance properties of Fe3 O4 -PDA and Au NR-pDM are applied to photoacoustic imaging and photothermal therapy. Besides, Fe3 O4 and Au NR components allow the nanocomposites to serve as MRI and CT contrast agents. The prepared positively charged Au@pDM/Fe3 O4 also can complex plasmid DNA into pDNA/Au@pDM/Fe3 O4 and efficiently mediated gene therapy. The multifunctional applications of pDNA/Au@pDM/Fe3 O4 nanocomposites in trimodal imaging and combined photothermal/gene therapy are demonstrated using a xenografted rat glioma nude mouse model. The present study demonstrates that the proper assembly of different inorganic nanoparticles and polycations is an effective strategy to construct new multifunctional theranostic systems. PMID:26996155

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

    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 μm 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 microspheres 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

  10. Fabrication of Bi-Fe3O4@RGO hybrids and their catalytic performance for the reduction of 4-nitrophenol

    Nanocatalysts are frequently connected to magnetic nanoparticles. These composites are easy to be retrieved from the reaction system under a magnetic field because of their magnetic properties. Magnetic separation is particularly promising in industry since it can solve many issues present in filtration, centrifugation, or gravitation separation. Herein, a facile method to prepare bismuth and Fe3O4 nanoparticles loaded on reduced graphene oxide magnetic hybrids (Bi-Fe3O4@RGO) using soluble starch as a dispersant is demonstrated. The magnetic Fe3O4 nanoparticles were synthesized by the co-precipitation of Fe2+ and Fe3+ ions, and Bi nanoparticles were fabricated by the redox reactions between sodium borohydride and ammonium bismuth citrate in the presence of soluble starch. Transmission electron microscopy images demonstrate that the average diameter of the Fe3O4 nanoparticles is about 5 nm and the diameters of Bi nanoparticles range from 10 to 20 nm. The magnetic Bi-Fe3O4@RGO hybrids exhibit high catalytic activity in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 with a first-order rate constant (K) of 0.00808 s−1 and is magnetically recyclable for at least five cycles. This strategy provides an efficient and recyclable catalyst for the use in environmental protection applications

  11. Synthesis and photocatalytic properties of Fe3O4@TiO2 core-shell for degradation of Rhodamine B

    Mufti, Nandang; Munfarriha, Ulfatien; Fuad, Abdulloh; Diantoro, Markus

    2016-02-01

    The aim of this research is to synthesis Fe3O4@TiO2 core-shell and used it as photocatalytic for degradation of Rhodamine B. The Fe3O4 nanoparticle core was synthesized by coprecipitation method from the iron sand. The TiO2 shell synthesized using coprecipitation method to capsulated Fe3O4 nanoparticle with vary of Fe3O4 mass. The Fe3O4@TiO2 core-shells were characterized using SEM-EDX, XRD. Photocatalytic activity of Rhodamine B degradation was performed under UV irradiation with variation of time exposure. The efficiency of photodegradation is measured by UV-Vis spectrophotometer. The XRD result showed that Fe3O4 nanoparticle is single phase with crystal size of 15.5 nm. The existence of Fe3O4 and anatase of TiO2 phases in the XRD pattern shows that The Fe3O4@TiO2 core-shells are successfully synthesized. While, the TiO2 shell is confirmed by thermal test up to 550 OC for two hours to the samples. Based on SEM characterization, The Fe3O4@TiO2 core-shells are agglomerated with averages diameter sizes of particles between 38.5 nm to 72.8 nm. The concentration of TiO2 decrease with increasing Fe3O4 mass with atomic composition of Fe/Ti elements in Fe3O4@TiO2 core-shells are 0.083, 1.12, and 1.48. Based on photo degradation test of Rhodamine B under UV irradiation, we conclude that the degradation of Rhodamin B is caused by absorbsion and photocatalytic mechanism. For photocatalytic mechanism the efficiency of photodegradation of Rhodamin B increases by increasing TiO2 concentration.

  12. Heterogeneous Fenton-like discoloration of methyl orange using Fe3O4/MWCNTs as catalyst: process optimization by response surface methodology

    Xu, Huan-Yan; Shi, Tian-Nuo; Zhao, Hang; Jin, Li-Guo; Wang, Feng-Chun; Wang, Chun-Yan; Qi, Shu-Yan

    2016-03-01

    Fe3O4/MWCNTs nanocomposites were prepared by chemical oxidation coprecipitation method and developed as highly efficient heterogeneous Fenton-like catalyst. XRD results revealed that Fe3O4 nanoparticles deposited onto MWCNTs surface remained the inverse spinel crystal structure of cubic Fe3O4 phase. The FTIR characteristic peaks of MWCNTs weakened or disappeared due to the anchor of Fe3O4 nanoparticles and Fe-O peak at 570 cm-1 was indicative of the formation of Fe3O4. TEM observation revealed that Fe3O4 nanoparticles were tightly anchored by MWCNTs. The Fenton-like catalytic activity of Fe3O4/MWCNTs nanocomposites for the discoloration of methyl orange (MO) was much higher than that of Fe3O4 nanoparticles. The process optimization of this heterogeneous Fenton-like system was implemented by response surface methodology (RSM). The optimum conditions for MO discoloration were determined to be of 12.3 mmol/L H2O2 concentration, 2.9 g/L catalyst dosage, solution pH 2.7 and 39.3 min reaction time, with the maximum predicted value for MO discoloration ratio of 101.85%. The corresponding experimental value under the identical conditions was obtained as 99.86%, which was very close to the predicted one with the absolute deviation of 1.99%.

  13. Preparation and Characterization of Fe3O4/Ethiodized-oil Magnetic Fluids Used in Arterial Embolization Hyperthermia

    罗志; 王益明; 洪若瑜; 李洪钟

    2012-01-01

    Fe3O4 nanoparticles (NPs) were prepared by the co-precipitation of Fe3+ and Fe2+ with ammonium hydroxide, and were modified by four different surfactants. The modified Fe3O4 NPs were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy and vibrating sample magne- tometer. Then, the modified Fe3O4 NPs were dispersed in ethiodized-oil by mechanical agitation and ultrasonic vi- bration to obtain stable Fe3O4 /ethiodized-oil magnetic fluids (MFs). The magnetic properties and rheological prop- erties of the MFs were measured using a Gouy magnetic balance and a rotational rheometer, respectively. The satu- ration magnetization of the Fe3O4 modified by oleic acid was 52.1 Emu/g. Furthermore, the result showed that the inductive heating effect of oleic acid stabilized Fe3O4/ethiodized-oil MF was remarkable and it only took 650 s for the temperature rising from 25 ℃ to 65 ℃. The specific absorption rate of the MF was 50.16 W/(g of Fe). It had a potential application in arterial embolization hyperthermia.

  14. Heterogenized Bimetallic Pd-Pt-Fe3O4 Nanoflakes as Extremely Robust, Magnetically Recyclable Catalysts for Chemoselective Nitroarene Reduction.

    Byun, Sangmoon; Song, Yeami; Kim, B Moon

    2016-06-15

    A very simple synthesis of bimetallic Pd-Pt-Fe3O4 nanoflake-shaped alloy nanoparticles (NPs) for cascade catalytic reactions such as dehydrogenation of ammonia-borane (AB) followed by the reduction of nitro compounds (R-NO2) to anilines or alkylamines (R-NH2) in methanol at ambient temperature is described. The Pd-Pt-Fe3O4 NPs were easily prepared via a solution phase hydrothermal method involving the simple one-pot coreduction of potassium tetrachloroplatinate (II) and palladium chloride (II) in polyvinylpyrrolidone with subsequent deposition on commercially available Fe3O4 NPs. The bimetallic Pd-Pt alloy NPs decorated on Fe3O4 NPs provide a unique synergistic effect for the catalysis of cascade dehydrogenation/reduction. Various nitroarene derivatives were reduced to anilines with very specific chemoselectivity in the presence of other reducible functional groups. The bimetallic Pd-Pt-Fe3O4 NPs provide a unique synergistic effect for the catalysis of cascade dehydrogenation/reduction. The nitro reduction proceeded in 5 min with nearly quantitative conversions and yields. Furthermore, the magnetically recyclable nanocatalysts were readily separated using an external magnet and reused up to 250 times without any loss of catalytic activity. A larger scale (10 mmol) reaction was also successfully performed with >99% yield. This efficient, recyclable Pd-Pt-Fe3O4 NPs system can therefore be repetitively utilized for the reduction of various nitro-containing compounds. PMID:27191706

  15. Multifunctional nanotube-like Fe3O4/PANI/CDs/Ag hybrids: An efficient SERS substrate and nanocatalyst.

    Yan, Manqing; Shen, Yang; Zhang, Guiyang; Bi, Hong

    2016-01-01

    In this paper, the stable and environment-friendly Fe3O4 nanotubes with polyaniline (Fe3O4 NTs/PANI hybrids) have been prepared via mesoporous anodic alumina oxide (AAO) template, sol-gel method and in-situ polymerization. Then multifunctional Fe3O4 NTs/PANI/Ag hybrids have been obtained by decorating Ag nanoparticles by glucose reduction on surface of Fe3O4 NTs/PANI hybrids. The morphologies and structures of these hybrids were subsequently investigated by SEM, XRD, TEM and XPS measurements. The Fe3O4 NTs/PANI/Ag hybrids presented high catalytic activity due to the template-assisted presence, preventing Ag particulate agglomeration. Importantly, the Fe3O4 NTs/PANI/Ag hybrids achieve sensitive surface-enhanced Raman scattering (SERS) signals. Furthermore, the introduction of carbon dots (CDs) endows these hybrids good dispersion and stable photoluminescence (PL). Therefore, the obtained hybrids may have potential applications in waste water treatment, biomedicine, photocatalyst, and environmental analysis. PMID:26478345

  16. Antifungal activity of multifunctional Fe3O4-Ag nanocolloids

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

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

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

    2013-04-01

    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.

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

    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 El