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1

Monodispersed core-shell Fe3O4@Au nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

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

Wang, L Y.; Luo, Jin; Fan, Quan; Suzuki, Masatsugu; Suzuki, Itsuko S.; Engelhard, Mark H.; Lin, Yuehe; Kim, Nam; Wang, JQ; Zhong, Chuan-Jian

2005-12-15

2

Modifying Fe 3O 4 nanoparticles with humic acid for removal of Rhodamine B in water  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Humic acid (HA) modifying Fe 3O 4 nanoparticles (Fe 3O 4/HA) was developed for removal of Rhodamine B from water. Fe 3O 4/HA was prepared by a coprecipitation procedure with cheap and environmentally friendly iron salts and HA. TEM images revealed the Fe 3O 4/HA (with ~10nm Fe 3O 4 cores) were aggre...

Peng, L; Qin, P; Lei, M; Zeng, Q; Song, H; Yang, J; Shao, J; Liao, B; Gu, J

3

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

International Nuclear Information System (INIS)

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

2009-01-01

4

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

Science.gov (United States)

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

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

2013-07-01

5

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

UK PubMed Central (United Kingdom)

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

Bian L; Bao L; Wang J; Lei J

2013-07-01

6

Synthesis and cellular compatibility of biomineralized Fe3O4 nanoparticles in tumor cells targeting peptides.  

UK PubMed Central (United Kingdom)

Fe3O4 nanoparticles (NPs) coated with WSG-peptide were prepared via a facile biomineralization technique at room temperature. The concentration of the peptides and the mixing time could substantially influence the morphology of as-prepared particles. The saturation magnetization of WSG-coated Fe3O4 particles were 35.92 emu/g, slightly higher than that of Fe3O4 without WSG peptides. Cell viability assay revealed that WSG-coated Fe3O4 particles had a good cellular compatibility. In addition, compared with Fe3O4 NPs, the mineralized Fe3O4 NPs coated with WSG peptides could more easily assemble into the cancer cell, indicating that the WSG-Fe3O4 NPs possess cancer targeting property. Thus, the WSG-coated Fe3O4 NPs could be used in cancer diagnosis and treatment fields.

Wei Y; Yin G; Ma C; Huang Z; Chen X; Liao X; Yao Y; Yin H

2013-07-01

7

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

International Nuclear Information System (INIS)

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

2013-01-01

8

Magnetic nanoparticles of Fe3O4 enhance docetaxel-induced prostate cancer cell death.  

UK PubMed Central (United Kingdom)

Docetaxel (DTX) is one of the most important anticancer drugs; however, the severity of its adverse effects detracts from its practical use in the clinic. Magnetic nanoparticles of Fe3O4 (MgNPs-Fe3O4) can enhance the delivery and efficacy of anticancer drugs. We investigated the effects of MgNPs-Fe3O4 or DTX alone, and in combination with prostate cancer cell growth in vitro, as well as with the mechanism underlying the cytotoxic effects. MgNPs-Fe3O4 caused dose-dependent increases in reactive oxygen species levels in DU145, PC-3, and LNCaP cells; 8-hydroxydeoxyguanosine levels were also elevated. MgNPs-Fe3O4 alone reduced the viability of LNCaP and PC-3 cells; however, MgNPs-Fe3O4 enhanced the cytotoxic effect of a low dose of DTX in all three cell lines. MgNPs-Fe3O4 also augmented the percentage of DU145 cells undergoing apoptosis following treatment with low dose DTX. Expression of nuclear transcription factor ?B in DU145 was not affected by MgNPs-Fe3O4 or DTX alone; however, combined treatment suppressed nuclear transcription factor ?B expression. These findings offer the possibility that MgNPs-Fe3O4-low dose DTX combination therapy may be effective in treating prostate cancer with limited adverse effects.

Sato A; Itcho N; Ishiguro H; Okamoto D; Kobayashi N; Kawai K; Kasai H; Kurioka D; Uemura H; Kubota Y; Watanabe M

2013-01-01

9

Magnetic nanoparticles of Fe3O4 enhance docetaxel-induced prostate cancer cell death  

Science.gov (United States)

Docetaxel (DTX) is one of the most important anticancer drugs; however, the severity of its adverse effects detracts from its practical use in the clinic. Magnetic nanoparticles of Fe3O4 (MgNPs-Fe3O4) can enhance the delivery and efficacy of anticancer drugs. We investigated the effects of MgNPs-Fe3O4 or DTX alone, and in combination with prostate cancer cell growth in vitro, as well as with the mechanism underlying the cytotoxic effects. MgNPs-Fe3O4 caused dose-dependent increases in reactive oxygen species levels in DU145, PC-3, and LNCaP cells; 8-hydroxydeoxyguanosine levels were also elevated. MgNPs-Fe3O4 alone reduced the viability of LNCaP and PC-3 cells; however, MgNPs-Fe3O4 enhanced the cytotoxic effect of a low dose of DTX in all three cell lines. MgNPs-Fe3O4 also augmented the percentage of DU145 cells undergoing apoptosis following treatment with low dose DTX. Expression of nuclear transcription factor ?B in DU145 was not affected by MgNPs-Fe3O4 or DTX alone; however, combined treatment suppressed nuclear transcription factor ?B expression. These findings offer the possibility that MgNPs-Fe3O4–low dose DTX combination therapy may be effective in treating prostate cancer with limited adverse effects.

Sato, Akiko; Itcho, Naoki; Ishiguro, Hitoshi; Okamoto, Daiki; Kobayashi, Naohito; Kawai, Kazuaki; Kasai, Hiroshi; Kurioka, Daisuke; Uemura, Hiroji; Kubota, Yoshinobu; Watanabe, Masatoshi

2013-01-01

10

Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to...

Masatoshi Watanabe; Misao Yoneda; Ayaka Morohashi; Yasuki Hori; Daiki Okamoto; Akiko Sato; Daisuke Kurioka; Tadashi Nittami

11

Preparation and antibacterial activity of Fe3O4-Ag nanoparticles  

International Nuclear Information System (INIS)

Bifunctional Fe3O4-Ag nanoparticles with both superparamagnetic and antibacterial properties were prepared by reducing silver nitrate on the surface of Fe3O4 nanoparticles using the water-in-oil microemulsion method. Formation of well-dispersed nanoparticles with sizes of 60 ± 20 nm was confirmed by transmission electron microscopy and dynamic light scattering. X-ray diffraction patterns and UV-visible spectroscopy indicated that both Fe3O4 and silver are present in the same particle. The superparamagnetism of Fe3O4-Ag nanoparticles was confirmed with a vibrating sample magnetometer. Their antibacterial activity was evaluated by means of minimum inhibitory concentration value, flow cytometry, and antibacterial rate assays. The results showed that Fe3O4-Ag nanoparticles presented good antibacterial performance against Escherichia coli (gram-negative bacteria), Staphylococcus epidermidis (gram-positive bacteria) and Bacillus subtilis (spore bacteria). Furthermore, Fe3O4-Ag nanoparticles can be easily removed from water by using a magnetic field to avoid contamination of surroundings. Reclaimed Fe3O4-Ag nanoparticles can still have antibacterial capability and can be reused

2007-07-18

12

Microwave dielectric and magnetic properties of superparamagnetic 8-nm Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

[en] The superparamagnetic 8-nm Fe3O4 nanoparticles were successfully prepared by chemical oxidation process. For the complex permittivity, the dual dielectric relaxation processes have been proved by two overlapped Cole–Cole semicircles, and the natural resonance frequency is 3.03 GHz for the complex permeability. The maximum reflection loss value reaches ?55.5 dB at 6.11 GHz with 3.85 mm in the thickness of the absorbers for the superparamagnetic 8-nm Fe3O4 nanoparticles which is better than that of 150 nm and 30 nm Fe3O4 nanoparticles. It is believed that the superparamagnetic 8-nm Fe3O4 nanoparticles can be used as a kind of candidate for microwave absorber. - Highlights: ? Superparamagnetic 8-nm Fe3O4 nanoparticles synthesized by the simple chemical oxidation. ? The dual dielectric relaxation processes have been proved by the two overlapped Cole–Cole semicircles for the complex permittivity. ? The natural resonance frequency is 3.03 GHz which is larger than the one of 150 nm and 30 nm Fe3O4 nanoparticles. ? These possess better microwave absorption properties than 150 nm and 30 nm Fe3O4 nanoparticles.

2012-01-01

13

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

Science.gov (United States)

Background Multidrug resistance in cancer is a major obstacle for clinical therapeutics, and is the reason for 90% of treatment failures. This study investigated the efficiency of novel multifunctional Fe3O4 magnetic nanoparticles (Fe3O4-MNP) combined with chemotherapy and hyperthermia for overcoming multidrug resistance in an in vivo model of leukemia. Methods Nude mice with tumor xenografts were randomly divided into a control group, and the treatment groups were allocated to receive daunorubicin, 5-bromotetrandrine (5-BrTet) and daunorubicin, Fe3O4-MNP, and Fe3O4-MNP coloaded with daunorubicin and 5-bromotetrandrine (Fe3O4-MNP-DNR-5-BrTet), with hyperthermia in an alternating magnetic field. We investigated tumor volume and pathology, as well as P-glycoprotein, Bcl-2, Bax, and caspase-3 protein expression to elucidate the effect of multimodal treatment on overcoming multidrug resistance. Results Fe3O4-MNP played a role in increasing tumor temperature during hyperthermia. Tumors became significantly smaller, and apoptosis of cells was observed in both the Fe3O4-MNP and Fe3O4-MNP-DNR-5-BrTet groups, especially in the Fe3O4-MNP-DNR-5-BrTet group, while tumor volumes in the other groups had increased after treatment for 12 days. Furthermore, Fe3O4-MNP-DNR-5-BrTet with hyperthermia noticeably decreased P-glycoprotein and Bcl-2 expression, and markedly increased Bax and caspase-3 expression. Conclusion Fe3O4-MNP-DNR-5-BrTet with hyperthermia may be a potential approach for reversal of multidrug resistance in the treatment of leukemia.

Ren, Yanyan; Zhang, Haijun; Chen, Baoan; Cheng, Jian; Cai, Xiaohui; Liu, Ran; Xia, Guohua; Wu, Weiwei; Wang, Shuai; Ding, Jiahua; Gao, Chong; Wang, Jun; Bao, Wen; Wang, Lei; Tian, Liang; Song, Huihui; Wang, Xuemei

2012-01-01

14

Tuning exchange bias in core/shell FeO/Fe3O4 nanoparticles.  

UK PubMed Central (United Kingdom)

Monodisperse 35 nm FeO nanoparticles (NPs) were synthesized and oxidized in a dry air atmosphere into core/shell FeO/Fe(3)O(4) NPs with both FeO core and Fe(3)O(4) shell dimensions controlled by reaction temperature and time. Temperature-dependent magnetic properties were studied on FeO/Fe(3)O(4) NPs obtained from the FeO NPs oxidized at 60 and 100 °C for 30 min. A large exchange bias (shift in the hysteresis loop) was observed in these core/shell NPs. The relative dimensions of the core and shell determine not only the coercivity and exchange field but also the dominant reversal mechanism of the ferrimagnetic Fe(3)O(4) component. This is the first time demonstration of tuning exchange bias and of controlling asymmetric magnetization reversal in FeO/Fe(3)O(4) NPs with antiferromagnetic core and ferrimagnetic shell.

Sun X; Huls NF; Sigdel A; Sun S

2012-01-01

15

Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells.  

UK PubMed Central (United Kingdom)

Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to investigate the cytotoxicity and genotoxicity of MgNPs-Fe3O4 in A549 human lung epithelial cells. MgNPs-Fe3O4 caused cell membrane damage, as assessed by the release of lactate dehydrogenase (LDH), only at a high concentration (100 ?g/mL); a lower concentration (10 ?g/mL) increased the production of reactive oxygen species, increased oxidative damage to DNA, and decreased the level of reduced glutathione. MgNPs-Fe3O4 caused a dose-dependent increase in the CD44+ fraction of A549 cells. MgNPs-Fe3O4 induced the expression of heme oxygenase-1 at a concentration of 1 ?g/mL, and in a dose-dependent manner. Despite these effects, MgNPs-Fe3O4 had minimal effect on cell viability and elicited only a small increase in the number of cells undergoing apoptosis. Together, these data suggest that MgNPs-Fe3O4 exert little or no cytotoxicity until a high exposure level (100 ?g/mL) is reached. This dissociation between elevated indices of cell damage and a small effect on cell viability warrants further study.

Watanabe M; Yoneda M; Morohashi A; Hori Y; Okamoto D; Sato A; Kurioka D; Nittami T; Hirokawa Y; Shiraishi T; Kawai K; Kasai H; Totsuka Y

2013-01-01

16

Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells  

Science.gov (United States)

Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to investigate the cytotoxicity and genotoxicity of MgNPs-Fe3O4 in A549 human lung epithelial cells. MgNPs-Fe3O4 caused cell membrane damage, as assessed by the release of lactate dehydrogenase (LDH), only at a high concentration (100 ?g/mL); a lower concentration (10 ?g/mL) increased the production of reactive oxygen species, increased oxidative damage to DNA, and decreased the level of reduced glutathione. MgNPs-Fe3O4 caused a dose-dependent increase in the CD44+ fraction of A549 cells. MgNPs-Fe3O4 induced the expression of heme oxygenase-1 at a concentration of 1 ?g/mL, and in a dose-dependent manner. Despite these effects, MgNPs-Fe3O4 had minimal effect on cell viability and elicited only a small increase in the number of cells undergoing apoptosis. Together, these data suggest that MgNPs-Fe3O4 exert little or no cytotoxicity until a high exposure level (100 ?g/mL) is reached. This dissociation between elevated indices of cell damage and a small effect on cell viability warrants further study.

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

2013-01-01

17

Versatile functionalization of Fe3O4 nanoparticles via RAFT polymerization and click chemistry  

Science.gov (United States)

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

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

2011-10-01

18

Magnetic and rheological properties of monodisperse Fe3O4 nanoparticle/organic hybrid  

International Nuclear Information System (INIS)

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

2009-01-01

19

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

International Nuclear Information System (INIS)

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

2007-04-11

20

Microwave dielectric and magnetic properties of superparamagnetic 8-nm Fe3O4 nanoparticles  

Science.gov (United States)

The superparamagnetic 8-nm Fe3O4 nanoparticles were successfully prepared by chemical oxidation process. For the complex permittivity, the dual dielectric relaxation processes have been proved by two overlapped Cole-Cole semicircles, and the natural resonance frequency is 3.03 GHz for the complex permeability. The maximum reflection loss value reaches -55.5 dB at 6.11 GHz with 3.85 mm in the thickness of the absorbers for the superparamagnetic 8-nm Fe3O4 nanoparticles which is better than that of 150 nm and 30 nm Fe3O4 nanoparticles. It is believed that the superparamagnetic 8-nm Fe3O4 nanoparticles can be used as a kind of candidate for microwave absorber.

Wen, Fusheng; Zhang, Fang; Zheng, Hong

2012-08-01

 
 
 
 
21

Spin transport in molecules studied by Fe3O4/molecule nanoparticles  

Science.gov (United States)

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

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

2013-05-01

22

Sonochemical fabrication of Fe3O4 nanoparticles on reduced graphene oxide for biosensors.  

UK PubMed Central (United Kingdom)

This study synthesized Fe(3)O(4) nanoparticles of 30-40nm by a sonochemical method, and these particles were uniformly dispersed on the reduced graphene oxide sheets (Fe(3)O(4)/RGO). The superparamagnetic property of Fe(3)O(4)/RGO was evidenced from a saturated magnetization of 30emu/g tested by a sample-vibrating magnetometer. Based on the testing results, we proposed a mechanism of ultrasonic waves to explain the formation and dispersion of Fe(3)O(4) nanoparticles on RGO. A biosensor was fabricated by modifying a glassy carbon electrode with the combination of Fe(3)O(4)/RGO and hemoglobin. The biosensor showed an excellent electrocatalytic reduction toward H(2)O(2) at a wide, linear range from 4×10(-6) to 1×10(-3)M (R(2)=0.994) as examined by amperometry, and with a detection limit of 2×10(-6)M. The high performance of H(2)O(2) detection is attributed to the synergistic effect of the combination of Fe(3)O(4) nanoparticles and RGO, promoting the electron transfer between the peroxide and electrode surface.

Zhu S; Guo J; Dong J; Cui Z; Lu T; Zhu C; Zhang D; Ma J

2013-05-01

23

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

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

24

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

Directory of Open Access Journals (Sweden)

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

Ren Y; Zhang H; Chen B; Cheng J; Cai X; Liu R; Xia G; Wu W; Wang S; Ding J; Gao C; Wang J; Bao W; Wang L; Tian L; Song H; Wang X

2012-01-01

25

Vancomycin-modified LaB6@SiO2/Fe3O4 composite nanoparticles for near-infrared photothermal ablation of bacteria.  

UK PubMed Central (United Kingdom)

LaB6 nanoparticles possess excellent near-infrared (NIR) photothermal conversion properties. Vancomycin can interact strongly with a broad range of Gram-positive and Gram-negative bacteria. Fe3O4 nanoparticles could be used as the carrier for magnetic separation. In this work, vancomycin and Fe3O4 nanoparticles were successfully bound onto the surface of LaB6 nanoparticles with a silica coating and carboxyl functionalization to fabricate vancomycin-modified LaB6@SiO2/Fe3O4 (Van-LaB6@SiO2/Fe3O4) composite nanoparticles as a novel nanomaterial for the NIR photothermal ablation of bacteria. From the analyses of absorption spectra, transmission electron microscopy images and X-ray diffraction patterns, the formation of Van-LaB6@SiO2/Fe3O4 composite nanoparticles was confirmed. The resulting Van-LaB6@SiO2/Fe3O4 composite nanoparticles possessed nearly superparamagnetic properties, retained the excellent NIR photothermal conversion property of LaB6 nanoparticles and could capture the bacteria Staphylococcus aureus and Escherichia coli efficiently. Owing to these capabilities, they were demonstrated to be quite efficient for the magnetic separation and NIR photothermal ablation of S. aureus and E. coli. Furthermore, the magnetic property made the Van-LaB6@SiO2/Fe3O4 composite nanoparticles useful for the magnetic assembling of bacteria, which could further enhance the photothermal ablation efficiency.

Lai BH; Chen DH

2013-07-01

26

Vancomycin-modified LaB6@SiO2/Fe3O4 composite nanoparticles for near-infrared photothermal ablation of bacteria.  

Science.gov (United States)

LaB6 nanoparticles possess excellent near-infrared (NIR) photothermal conversion properties. Vancomycin can interact strongly with a broad range of Gram-positive and Gram-negative bacteria. Fe3O4 nanoparticles could be used as the carrier for magnetic separation. In this work, vancomycin and Fe3O4 nanoparticles were successfully bound onto the surface of LaB6 nanoparticles with a silica coating and carboxyl functionalization to fabricate vancomycin-modified LaB6@SiO2/Fe3O4 (Van-LaB6@SiO2/Fe3O4) composite nanoparticles as a novel nanomaterial for the NIR photothermal ablation of bacteria. From the analyses of absorption spectra, transmission electron microscopy images and X-ray diffraction patterns, the formation of Van-LaB6@SiO2/Fe3O4 composite nanoparticles was confirmed. The resulting Van-LaB6@SiO2/Fe3O4 composite nanoparticles possessed nearly superparamagnetic properties, retained the excellent NIR photothermal conversion property of LaB6 nanoparticles and could capture the bacteria Staphylococcus aureus and Escherichia coli efficiently. Owing to these capabilities, they were demonstrated to be quite efficient for the magnetic separation and NIR photothermal ablation of S. aureus and E. coli. Furthermore, the magnetic property made the Van-LaB6@SiO2/Fe3O4 composite nanoparticles useful for the magnetic assembling of bacteria, which could further enhance the photothermal ablation efficiency. PMID:23535232

Lai, Bo-Hung; Chen, Dong-Hwang

2013-03-25

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Synthesis and characterization of Fe3O4 nanoparticles coated with fucan polysaccharides  

Science.gov (United States)

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

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

2013-10-01

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Monodispersed core-shell Fe3O4(at)Au nanoparticles  

International Nuclear Information System (INIS)

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

2005-12-15

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

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We investigated the effect of magnetic nanoparticles of Fe3O4 (Fe3O4-MNPs) on the mice immune system. Imprinting control region (ICR) mice were assigned randomly into four groups and treated with normal saline or low, medium, or high doses of Fe3O4-MNPs, respectively. After intravenous administratio...

Chen, Bao-An; Jin, Nan; Wang, Jun; Ding, Jiahua; Gao, Chong; Cheng, Jian; Xia, Guohua; Gao, Feng; Zhou, Yin; Chen, Yue

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

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The present study evaluated whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) could enhance the activity of artesunate (ART), and to explore its potential mechanisms. Cytotoxicity of the copolymer of ART with MNPs-Fe3O4 on K562 cells was detected by MTT assay and the apoptosis rate of K562 ce...

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

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

Science.gov (United States)

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

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

2013-07-01

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The Nature of Magnetic State of Small Fe3O4 Nanoparticles  

Directory of Open Access Journals (Sweden)

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

U. Sobo?an; Gaehang Lee; Hyun-Wook Kang; Hae Jin Kim; Z. Jagli?i?; J. Dolinšek

2011-01-01

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Preparation and application of core–shell Fe3O4/polythiophene nanoparticles  

International Nuclear Information System (INIS)

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

2011-01-01

34

Green synthesis and characterization of superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

[en] In this paper, we have first demonstrated a facile and green synthetic approach for preparing superparamagnetic Fe3O4 nanoparticles using ?-D-glucose as the reducing agent and gluconic acid (the oxidative product of glucose) as stabilizer and dispersant. The X-ray powder diffraction (XRD), X-ray photoelectron spectrometry (XPS), and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that Fe3O4 nanoparticles were roughly spherical shape and its average size was about 12.5 nm. The high-resolution TEM (HRTEM) result proved that the nanoparticles were structurally uniform with a lattice fringe spacing about 0.25 nm, which corresponded well with the values of 0.253 nm of the (3 1 1) lattice plane of the inverse spinel Fe3O4 obtained from the JCPDS database. The superconducting quantum interference device (SQUID) results revealed that the blocking temperature (Tb) was 190 K, and that the magnetic hysteresis loop at 300 K showed a saturation magnetization of 60.5 emu/g, and the absence of coercivity and remanence indicated that the as-synthesized Fe3O4 nanoparticles had superparamagnetic properties. Fourier transform infrared spectroscopy (FT-IR) spectrum displayed that the characteristic band of Fe-O at 569 cm-1 was indicative of Fe3O4. This method might provide a new, mild, green, and economical concept for the synthesis of other nanomaterials.

2010-01-01

35

Green synthesis of soya bean sprouts-mediated superparamagnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

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

2010-01-01

36

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

UK PubMed Central (United Kingdom)

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

He L; Yao L; Liu F; Qin B; Song R; Huang W

2010-10-01

37

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

Science.gov (United States)

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

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

2013-09-01

38

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

Directory of Open Access Journals (Sweden)

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

Chen DZ; Tang QS; Li XD; Zhou XJ; Zang J; Xue WQ; Xiang JY; Guo CQ

2012-01-01

39

Magneto capacitance in Fe3O4 and NiFe2O4 nanoparticles  

International Nuclear Information System (INIS)

[en] We have synthesized NiFe2O4 (? ?6 nm) and Fe3O4 (??30 nm) magnetic nanoparticles by solvothermal synthesis; furthermore the Fe3O4 nanoparticles have been coated with a SiO2 shell of approximately 5 nm of thickness by the Stober method. In the study of the dielectric properties as a function of the frequency, temperature and applied magnetic field, we observe a magnetocapacitive behavior (MC) at room temperature and under a moderate magnetic field (H=0.5T), that is specially important in the case of the Fe3O4, nanoparticles (MC 6%). On the other hand, the NiFe2O4 and Fe3O4atSiO2 samples present smaller magnetocapacitive effects: MC? 2% y MC? 1%, respectively. These MC values, that are higher than those reported in the literature for other related magnetic nanoparticles, corroborate the theoretical model proposed by Catalan in which the combination of Maxwell-Wagner effects and magnetoresistance promote the appearance of stronger magnetocapacitive effects. (Author)

2010-01-01

40

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

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Biodesulfurization (BDS) of dibenzothiophene (DBT) was carried out by Rhodococcus erythropolis IGST8 decorated with magnetic Fe3O4 nanoparticles, synthesized in-house by a chemical method, with an average size of 45-50 nm, in order to facilitate the post-reaction separation of the bacteria from the ...

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

 
 
 
 
41

Magnetoresistive properties of Fe3O4 nanoparticles embedded in a Cu matrix  

Science.gov (United States)

We studied ordered arrays of magnetic nanoparticles (NPs) in a nonmagnetic matrix. The influence of annealing temperature and measurement geometry (varying angle between sample surface and external magnetic field direction) on magnetoresistance and coercive field values was established. Measurements were done on the Au(2 nm)/Cu(20 nm)/Fe3O4(NPs)/SiO2/Si system.

Nepijko, S. A.; Elmers, H. J.; Schönhense, G.; Demydenko, M. H.; Protsenko, S. I.; Kostyuk, D. M.

2013-08-01

42

Orthogonal optimization design for preparation of Fe3O4 nanoparticles via chemical coprecipitation  

Science.gov (United States)

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

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

2013-09-01

43

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

Science.gov (United States)

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

Zhang, Hui; Zhu, Guoqing

2012-03-01

44

Alcohol dependent production of Fe3O4 and CoFe2O4 nanoparticles.  

Science.gov (United States)

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

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

2013-06-01

45

A sensitive choline biosensor using Fe3O4 magnetic nanoparticles as peroxidase mimics.  

Science.gov (United States)

A sensitive choline biosensor using Fe(3)O(4) magnetic nanoparticles and a choline oxidase modified gold electrode was developed. Fe(3)O(4) magnetic nanoparticles as peroxidase mimics used in the choline biosensor can not only improve the sensitivity of the response signal, but also possess the favorable properties of stability, magnetic separation and easy preparation, etc. When using the reduction currents of square wave voltammetry as the detection signals, the interferences of ascorbic acid and uric acid to the choline biosensor can be reduced effectively. The reduction currents of the square wave voltammetry were increased with the logarithm values of the choline chloride concentration (from 10(-9) to 10(-2) M), the detection limit was estimated to be 0.1 nM (S/N = 3). This choline biosensor also exhibited favorable selectivity and stability in the determination of choline chloride. PMID:21966671

Zhang, Zhanxia; Wang, Xiaolei; Yang, Xiurong

2011-10-03

46

A sensitive choline biosensor using Fe3O4 magnetic nanoparticles as peroxidase mimics.  

UK PubMed Central (United Kingdom)

A sensitive choline biosensor using Fe(3)O(4) magnetic nanoparticles and a choline oxidase modified gold electrode was developed. Fe(3)O(4) magnetic nanoparticles as peroxidase mimics used in the choline biosensor can not only improve the sensitivity of the response signal, but also possess the favorable properties of stability, magnetic separation and easy preparation, etc. When using the reduction currents of square wave voltammetry as the detection signals, the interferences of ascorbic acid and uric acid to the choline biosensor can be reduced effectively. The reduction currents of the square wave voltammetry were increased with the logarithm values of the choline chloride concentration (from 10(-9) to 10(-2) M), the detection limit was estimated to be 0.1 nM (S/N = 3). This choline biosensor also exhibited favorable selectivity and stability in the determination of choline chloride.

Zhang Z; Wang X; Yang X

2011-12-01

47

Identification of Ferrous-Ferric Fe3O4 Nanoparticles in Recombinant Human Ferritin Cages.  

UK PubMed Central (United Kingdom)

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

Walls MG; Cao C; Yu-Zhang K; Li J; Che R; Pan Y

2013-08-01

48

Aerosol-assisted synthesis of thiol-functionalized mesoporous silica spheres with Fe3O4 nanoparticles.  

Science.gov (United States)

Thiol-functionalized mesoporous silica spheres having Fe3O4 nanoparticles are fabricated in one-pot by aerosol-assisted synthesis. A TEM image shows that Fe3O4 nanoparticles are successfully embedded within the mesoporous silica spheres. SEM images and SAXS profiles reveals that the encapsulating Fe3O4 nanoparticles do not affect the ordering of a mesoporous structure. The spherical morphologies are also well retained. The presence of cage-type mesopores with uniform size is confirmed by N2 adsorption-desorption isotherms and TEM observations. The spray-dried thiol-functionalized particles with Fe3O4 nanoparticles effectively adsorb mercury (II) ions due to their strong interaction to thiol groups embedded in the framework. The particles with the amount of Fe3O4 nanoparticles (3.5 wt%) show a saturated magnetization (over 1.0 emu/g). This magnetic property is useful for practical collection with magnet. PMID:21137770

Suzuki, Norihiro; Gupta, Prashant; Sukegawa, Hiroaki; Inomata, Kouichiro; Inoue, Satoru; Yamauchi, Yusuke

2010-10-01

49

Aerosol-assisted synthesis of thiol-functionalized mesoporous silica spheres with Fe3O4 nanoparticles.  

UK PubMed Central (United Kingdom)

Thiol-functionalized mesoporous silica spheres having Fe3O4 nanoparticles are fabricated in one-pot by aerosol-assisted synthesis. A TEM image shows that Fe3O4 nanoparticles are successfully embedded within the mesoporous silica spheres. SEM images and SAXS profiles reveals that the encapsulating Fe3O4 nanoparticles do not affect the ordering of a mesoporous structure. The spherical morphologies are also well retained. The presence of cage-type mesopores with uniform size is confirmed by N2 adsorption-desorption isotherms and TEM observations. The spray-dried thiol-functionalized particles with Fe3O4 nanoparticles effectively adsorb mercury (II) ions due to their strong interaction to thiol groups embedded in the framework. The particles with the amount of Fe3O4 nanoparticles (3.5 wt%) show a saturated magnetization (over 1.0 emu/g). This magnetic property is useful for practical collection with magnet.

Suzuki N; Gupta P; Sukegawa H; Inomata K; Inoue S; Yamauchi Y

2010-10-01

50

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

Science.gov (United States)

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

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

2013-06-01

51

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

Directory of Open Access Journals (Sweden)

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

Li Y; Liu J; Zhong Y; Zhang J; Wang Z; Wang L; An Y; Lin M; Gao Z; Zhang D

2011-01-01

52

Characterization of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles  

Science.gov (United States)

In this study, we compare the characteristics of ferrogels prepared using ?-Fe2O3 and Fe3O4 nanoparticles. The magnetic nanoparticles with ~ 20 nm diameter were distributed in N-isopropylacrylamide (NIPAM) gel prepared using N,N'-methylenebisacrylamide (BIS), ammonium persulfate (APS) and N,N,N',N'-tetramethylethylenediamine (TEMED). Particle distribution and agglomeration characteristics of the prepared ferrogels were investigated using ultra small angle x-ray scattering (USAXS) and transmission electron microscopy (TEM). The ferrogel samples prepared using Fe3O4 and ?-Fe2O3 particles have similar particle distribution. The ferrogels, prepared with ?-Fe2O3 nanoparticles, however, demonstrate significantly different agglomeration characteristics compared to the ferrogels prepared using Fe3O4. In both systems, the agglomerated particles appear to be spherical, with few of those indicating chain like structures. Based on the particle concentration and sizes, the DC SQUID magnetometry data of these samples showed the magnetic moments range between 0.9 to 2.5 emu/g. Details of our results and analysis are presented.

Suthar, Kamlesh J.; Ghantasala, Muralidhar K.; Mancini, Derrick C.; Ilavsky, Jan

2009-03-01

53

An Fe3O4-nanoparticles-based amperometric biosensor for creatine determination.  

UK PubMed Central (United Kingdom)

An amperometric biosensor for the detection of creatine was designed, based on carbon paste electrode modified with Fe(3)O(4) nanoparticles. Electron transfer properties of unmodified and Fe(3)O(4)-nanoparticles-modified carbon paste electrodes were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. Fe(3)O(4) nanoparticles increased the surface area and electric conductivity of the electrode, thus enhancing the sensitivity of the electrode. Optimum pH, buffer concentration, working potential and enzyme loading were selected as 7.0; 0.05 mol L(-1); +0.30 V and 2.0 Unit creatinase (CI), 1.0 Unit sarcosine oxidase (SO), respectively. The purposed biosensor exhibited linear response from 2.0 × 10(-7) mol L(-1) to 3.8 × 10(-6) mol L(-1) and from 9.0 × 10(-6) mol L(-1) to 1.2 × 10(-4) mol L(-1) with a detection limit of 2.0 × 10(-7) mol L(-1). Biosensor was used for determination of creatine in commercial creatine powder samples and showed a good sensing performance.

Kaçar C; Erden PE; Pekyardimci S; Kiliç E

2013-02-01

54

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

UK PubMed Central (United Kingdom)

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

Yang Z; Zhang C; Zhang J; Bai W

2014-01-01

55

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

Science.gov (United States)

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

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

2013-08-06

56

Study on the Synthesis and Properties of Superparamagnetic Monodisperse Fe3O4 Nanoparticles  

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

57

Bi-functional properties of Fe3O4@YPO4:Eu hybrid nanoparticles: hyperthermia application.  

UK PubMed Central (United Kingdom)

Magnetic nanoparticles based hyperthermia therapy is a possible low cost and effective technique for killing cancer tissues in the human body. Fe3O4 and Fe3O4@YPO4:5Eu hybrid magnetic nanoparticles are prepared by co-precipitation method and their average particle sizes are found to be ?10 and 25 nm, respectively. The particles are spherical, non-agglomerated and highly dispersible in water. The crystallinity of as-prepared YPO4:5Eu sample is more than Fe3O4@YPO4:5Eu hybrid magnetic nanoparticles. The chemical bonds interaction between Fe3O4 and YPO4:5Eu is confirmed through FeO-P. The magnetization of hybrid nanocomposite shows magnetization Ms = 11.1 emu g(-1) with zero coercivity (measured at 2 × 10(-4) Oe) at room temperature indicating superparamagnetic behaviour. They attain hyperthermia temperature (~42 °C) under AC magnetic field showing characteristic induction heating of the prepared nanohybrid and they will be potential material for biological application. Samples produce the red emission peaks at 618 nm and 695 nm, which are in range of biological window. The quantum yield of YPO4:5Eu sample is found to be 12%. Eu(3+) present on surface and core could be distinguished from luminescence decay study. Very high specific absorption rate up to 100 W g(-1) could be achieved. The intracellular uptake of nanocomposites is found in mouse fibrosarcoma (Wehi 164) tumor cells by Prussian blue staining.

Prasad AI; Parchur AK; Juluri RR; Jadhav N; Pandey BN; Ningthoujam RS; Vatsa RK

2013-04-01

58

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.  

Science.gov (United States)

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis. PMID:23478269

Villani, M; Rimoldi, T; Calestani, D; Lazzarini, L; Chiesi, V; Casoli, F; Albertini, F; Zappettini, A

2013-03-12

59

Spin Disorder and Magnetic Anisotropy in Fe3O4 Nanoparticles  

CERN Multimedia

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

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

2006-01-01

60

Arsenic (V) adsorption on Fe3O4 nanoparticle-coated boron nitride nanotubes.  

UK PubMed Central (United Kingdom)

Multiwalled boron nitride nanotubes (BNNTs) functionalized with Fe(3)O(4) nanoparticles (NPs) were used for arsenic removal from water solutions. Sonication followed by a heating process was developed to in situ functionalize Fe(3)O(4) NPs onto a tube surface. A batch of adsorption experiments conducted at neutral pH (6.9) and room temperature (25 °C) and using the developed nanocomposites revealed effective arsenic (V) removal. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms were measured for a range of As(V) initial concentrations from 1 to 40 mg/L under the same conditions. The equilibrium data well fitted all isotherms, indicating that the mechanism for As(V) adsorption was a combination of chemical complexation and physical electrostatic attraction with a slight preference for chemisorption. The magnetite NPs functionalized on BNNTs led to a simple and rapid separation of magnetic metal-loaded adsorbents from the treated water under an external magnetic field.

Chen R; Zhi C; Yang H; Bando Y; Zhang Z; Sugiur N; Golberg D

2011-07-01

 
 
 
 
61

Composite multifunctional nanostructures based on ZnO tetrapods and superparamagnetic Fe3O4 nanoparticles.  

UK PubMed Central (United Kingdom)

A nanocomposite material is obtained by coupling superparamagnetic magnetite nanoparticles (Fe3O4 NP) and vapor phase grown zinc oxide nanostructures with 'tetrapod' morphology (ZnO TP). The aim is the creation of a multifunctional material which retains the attractive features of ZnO (e.g. surface reactivity, strong UV emission, piezoelectricity) together with added magnetism. Structural, morphological, optical, magnetic and functional characterization are performed. In particular, the high saturation magnetization of Fe3O4 NP (above 50 A m(2) kg(-1)), the strong UV luminescence and the enhanced photocatalytic activity of coupled nanostructures are discussed. Thus the nanocomposite turns out to be suitable for applications in energy harvesting and conversion, gas- and bio-sensing, bio-medicine and filter-free photocatalysis.

Villani M; Rimoldi T; Calestani D; Lazzarini L; Chiesi V; Casoli F; Albertini F; Zappettini A

2013-04-01

62

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

UK PubMed Central (United Kingdom)

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.

Shan D; Shi Y; Duan S; Wei Y; Cai Q; Yang X

2013-08-01

63

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

To explore whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) loaded with cisplatin can reverse the diaminedichloro platinum (DDP) resistance to multidrug resistance of ovarian carcinoma cells and to investigate its mechanisms. The SKOV3/DDP cells were divided into DDP treatment (DDP group), M...

Jiang, Zhi; Chen, Bao-An; Xia, Guo-Hua; Wu, Qiang; Zhang, Yu; Hong, Tie-Yan; Zhang, Wei; Cheng, Jian; Gao, Feng; Liu, Li-Jie

64

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this study was to investigate the potential effects of combination therapy using magnetic nanoparticles of Fe3O4 (MNP-Fe3O4) and chemotherapeutic drugs on lymphoma cells. Proliferation, inhibition, and viability of Raji cells were detected by MTT and trypan blue exclusion. The percent...

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

65

Preparation and properties of bio-compatible magnetic Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

In this work, we study the preparation and properties of bio-compatible magnetic nanoparticles for immunoassay and DNA detection. The magnetite (Fe3O4) nanoparticles were prepared by a chemical co-precipitation method and dextran was selected as the surfactant to suspend the nanoparticles. Suspended particles associated with avidin followed by biotin were qualitatively analyzed by enzyme-linked immunosorbent assay (ELISA) method. We found further the ethylenediamine blocked activated residual groups efficiently, hence enhancing the attachment of biotin for probing the avidin.

2006-01-01

66

Photodegradation of Methylred using Ag-doped Fe3O4 Nanoparticles  

Directory of Open Access Journals (Sweden)

Full Text Available A modified photocatalyst, Ag-doped Fe3O4 nanoparticle that can photodegrade effectively the organic pollutants, specifically methylred, an anionic azo dye in the dispersion system via a green chemicstry route is reported in this paper. The uniqueness of the potential photocatalyst is its subsequent recyclability by applying magnetic force. The synthesized photocatalyst by liquid impregnation method was characterized by XRD, SEM and EDX spectral techniques. An enhancement in the degradation rate was observed with Ag-doped Fe3O4 /UV/H2O2 system. The effect of various parameters such as irradiation time of sun light/ UV light/ amount of photocatalyst/pH/dye concentration on the decolourisation process was investigated. The degradation kinetics of methyl red by the photocatalyst was analysed by Langmuir-Hinshelwood model. The results revealed that photcatalytic degradation of methylred by Ag-doped Fe3O4 could be considered as a practical and reliable technique for the removal of environmental pollutants.

Lydia I. S.; Merlin J. P.; Dhayabaran V. V.; Radhik N.

2012-01-01

67

Fluorescence and magnetic properties of hydrogels containing Fe3O4 nanoparticles  

Science.gov (United States)

In this study, Fe3O4 (magnetite) nanoparticles were synthesized by in situ in polyacrylamide (PAAm) gels. Structural and magnetic properties of magnetite nanoparticles were investigated by X-Ray diffractometry (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM) methods. Interaction of pyranine molecules with Fe3O4 nanoparticles was investigated by fluorescence spectroscopy measurements in which pyranine (POH) molecules were used as a flouroprobe. It was observed that magnetite nanoparticles have single domain structure with average grain size of 12 nm which was also supported by magnetization measurements. M–H hysteresis curves revealed the superparamagnetic nature of magnetite nanoparticles synthesized in PAAm gels. Fluorescence measurements depicted that there is an interaction between POH and magnetite nanoparticles which was deduced from the presence of two new peaks at 380 nm and 405 nm in emission spectrum. Besides, it was observed that POH molecules could not diffuse into the gel when it consists of magnetite nanoparticles which also make the gel more homogeneous. As swelling ratio increases from 1 to 13, magnetization of the gel does not change which reveals that magnetic nanoparticles do not diffuse out of the gel during water-intake. This feature makes the gel suitable for applications as waste water treatments.

Alvero?lu, E.; Sözeri, H.; Baykal, A.; Kurtan, U.; ?enel, M.

2013-04-01

68

Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications  

International Nuclear Information System (INIS)

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

2011-01-01

69

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

Science.gov (United States)

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

Teymourian, Hazhir; Salimi, Abdollah; Khezrian, Somayeh

2013-04-30

70

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

UK PubMed Central (United Kingdom)

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

Teymourian H; Salimi A; Khezrian S

2013-11-01

71

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

Science.gov (United States)

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

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

2013-08-01

72

Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications  

Science.gov (United States)

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.

Plouffe, Brian D.; Nagesha, Dattatri K.; Dipietro, Robert S.; Sridhar, Srinvas; Heiman, Don; Murthy, Shashi K.; Lewis, Lewis H.

2011-09-01

73

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

Directory of Open Access Journals (Sweden)

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

Dorniani D; Bin Hussein MZ; Kura AU; Fakurazi S; Shaari AH; Ahmad Z

2012-01-01

74

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

Directory of Open Access Journals (Sweden)

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

Chockalingam Ashwin; Babu Heman; Chittor Raghuraman; Tiwari Jai

2010-01-01

75

Composites of aminodextran-coated Fe3O4 nanoparticles and graphene oxide for cellular magnetic resonance imaging.  

Science.gov (United States)

Formation of composites of dextran-coated Fe(3)O(4) nanoparticles (NPs) and graphene oxide (Fe(3)O(4)-GO) and their application as T(2)-weighted contrast agent for efficient cellular magnetic resonance imaging (MRI) are reported. Aminodextran (AMD) was first synthesized by coupling reaction of carboxymethyldextran with butanediamine, which was then chemically conjugated to meso-2,3-dimercaptosuccinnic acid-modified Fe(3)O(4) NPs. Next, the AMD-coated Fe(3)O(4) NPs were anchored onto GO sheets via formation of amide bond in the presence of 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC). It is found that the Fe(3)O(4)-GO composites possess good physiological stability and low cytotoxicity. Prussian Blue staining analysis indicates that the Fe(3)O(4)-GO nanocomposites can be internalized efficiently by HeLa cells, depending on the concentration of the composites incubated with the cells. Furthermore, compared with the isolated Fe(3)O(4) NPs, the Fe(3)O(4)-GO composites show significantly enhanced cellular MRI, being capable of detecting cells at the iron concentration of 5 ?g mL(-1) with cell density of 2 × 10(5) cells mL(-1), and at the iron concentration of 20 ?g mL(-1) with cell density of 1000 cells mL(-1). PMID:21882840

Chen, Weihong; Yi, Peiwei; Zhang, Yi; Zhang, Liming; Deng, Zongwu; Zhang, Zhijun

2011-09-19

76

Composites of aminodextran-coated Fe3O4 nanoparticles and graphene oxide for cellular magnetic resonance imaging.  

UK PubMed Central (United Kingdom)

Formation of composites of dextran-coated Fe(3)O(4) nanoparticles (NPs) and graphene oxide (Fe(3)O(4)-GO) and their application as T(2)-weighted contrast agent for efficient cellular magnetic resonance imaging (MRI) are reported. Aminodextran (AMD) was first synthesized by coupling reaction of carboxymethyldextran with butanediamine, which was then chemically conjugated to meso-2,3-dimercaptosuccinnic acid-modified Fe(3)O(4) NPs. Next, the AMD-coated Fe(3)O(4) NPs were anchored onto GO sheets via formation of amide bond in the presence of 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC). It is found that the Fe(3)O(4)-GO composites possess good physiological stability and low cytotoxicity. Prussian Blue staining analysis indicates that the Fe(3)O(4)-GO nanocomposites can be internalized efficiently by HeLa cells, depending on the concentration of the composites incubated with the cells. Furthermore, compared with the isolated Fe(3)O(4) NPs, the Fe(3)O(4)-GO composites show significantly enhanced cellular MRI, being capable of detecting cells at the iron concentration of 5 ?g mL(-1) with cell density of 2 × 10(5) cells mL(-1), and at the iron concentration of 20 ?g mL(-1) with cell density of 1000 cells mL(-1).

Chen W; Yi P; Zhang Y; Zhang L; Deng Z; Zhang Z

2011-10-01

77

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

International Nuclear Information System (INIS)

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

2009-01-14

78

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

Science.gov (United States)

Preparation of novel magneto-fluorescence polystyrene microsphere containing Fe3O4 and CdS nanoparticles by hydrothermal decomposition of cadmium O,O?-diethyl dithiophosphate in water on the polystyrene microspheres supported Fe3O4 nanoparticles.

Kaboudin, Babak; Ghaderian, Abolfazl

2013-10-01

79

Phospholipid-driven long-range ordering of Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

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

2011-01-15

80

Fluorescent magnetic fe3 o4 /rare Earth colloidal nanoparticles for dual-modality imaging.  

UK PubMed Central (United Kingdom)

Fluorescent magnetic colloidal nanoparticles (FMCNPs) are produced by a two-step, seed emulsifier-free emulsion polymerization in the presence of oleic acid and sodium undecylenate-modified Fe3 O4 nanoparticles (NPs). The Fe3 O4 /poly(St-co-GMA) nanoparticles are first synthesized as the seed and Eu(AA)3 Phen is copolymerized with the remaining St and GMA to form the fluorescent polymer shell in the second step. The uniform core-shell structured FMCNPs with a mean diameter of 120 nm exhibit superparamagnetism with saturation magnetization of 1.92 emu/g. Red luminescence from the FMCNPs is confirmed by the salient fluorescence emission peaks of europium ions at 594 and 619 nm as well as 2-photon confocal scanning laser microscopy. The in vitro cytotoxicity test conducted using the MTT assay shows good cytocompatibility and the T2 relaxivity of the FMCNPs is 353.86 mM(-1) S(-1) suggesting its potential in magnetic resonance imaging (MRI). In vivo MRI studies based on a rat model show significantly enhanced T2 -weighted images of the liver after administration and prussian blue staining of the liver tissue slice reveals accumulation of FMCNPs in the organ. The cytocompatibility, superparamagnetism, and excellent fluorescent properties of FMCNPs make them suitable for biological imaging probes in MRI and optical imaging.

Zhu H; Shang Y; Wang W; Zhou Y; Li P; Yan K; Wu S; Yeung KW; Xu Z; Xu H; Chu PK

2013-09-01

 
 
 
 
81

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

UK PubMed Central (United Kingdom)

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

Mukherjee J; Solanki K; Gupta MN

2013-01-01

82

Carbon-encapsulated Fe3O4 nanoparticles as a high-rate lithium ion battery anode material.  

UK PubMed Central (United Kingdom)

A facile and scalable in situ synthesis strategy is developed to fabricate carbon-encapsulated Fe3O4 nanoparticles homogeneously embedded in two-dimensional (2D) porous graphitic carbon nanosheets (Fe3O4@C@PGC nanosheets) as a durable high-rate lithium ion battery anode material. With assistance of the surface of NaCl particles, 2D Fe@C@PGC nanosheets can be in situ synthesized by using the Fe(NO3)3·9H2O and C6H12O6 as the metal and carbon precursor, respectively. After annealing under air, the Fe@C@PGC nanosheets can be converted to Fe3O4@C@PGC nanosheets, in which Fe3O4 nanoparticles (?18.2 nm) coated with conformal and thin onion-like carbon shells are homogeneously embedded in 2D high-conducting carbon nanosheets with a thickness of less than 30 nm. In the constructed architecture, the thin carbon shells can avoid the direct exposure of encapsulated Fe3O4 to the electrolyte and preserve the structural and interfacial stabilization of Fe3O4 nanoparticles. Meanwhile, the flexible and conductive PGC nanosheets can accommodate the mechanical stress induced by the volume change of embedded Fe3O4@C nanoparticles as well as inhibit the aggregation of Fe3O4 nanoparticles and thus maintain the structural and electrical integrity of the Fe3O4@C@PGC electrode during the lithiation/delithiation processes. As a result, this Fe3O4@C@PGC electrode exhibits superhigh rate capability (858, 587, and 311 mAh/g at 5, 10, and 20 C, respectively, 1 C = 1 A/g) and extremely excellent cycling performance at high rates (only 3.47% capacity loss after 350 cycles at a high rate of 10 C), which is the best one ever reported for an Fe3O4-based electrode including various nanostructured Fe3O4 anode materials, composite electrodes, etc.

He C; Wu S; Zhao N; Shi C; Liu E; Li J

2013-05-01

83

Near-infrared laser light mediated cancer therapy by photothermal effect of Fe3O4 magnetic nanoparticles.  

UK PubMed Central (United Kingdom)

The photothermal effect of Fe3O4 magnetic nanoparticles is investigated for cancer therapy both in vitro and in vivo experiments. Heat is found to be rapidly generated by red and near-infrared (NIR) range laser irradiation of Fe3O4 nanoparticles with spherical, hexagonal and wire-like shapes. These Fe3O4 nanoparticles are coated with carboxyl-terminated poly (ethylene glycol)-phospholipid for enhanced dispersion in water. The surface-functionalized Fe3O4 nanoparticles can be taken up by esophageal cancer cells and do not obviously affect the cell structure and viability. Upon irradiation at 808 nm however, the esophageal cancer cell viability is effectively suppressed, and the cellular organelles are obviously damaged when incubated with the NIR laser activated Fe3O4 nanoparticles. Mouse esophageal tumor growth was found to be significantly inhibited by the photothermal effect of Fe3O4 nanoparticles, resulting in effective tumor reduction. A morphological examination revealed that after a photothermal therapy, the tumor tissue structure exhibited discontinuation, the cells were significantly shriveled and some cells have finally disintegrated.

Chu M; Shao Y; Peng J; Dai X; Li H; Wu Q; Shi D

2013-05-01

84

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

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

Mukherjee Joyeeta; Gupta Munishwar N

2012-01-01

85

Fast defluorination and removal of norfloxacin by alginate/Fe@Fe3O4 core/shell structured nanoparticles.  

UK PubMed Central (United Kingdom)

Alginate-Fe(2+)/Fe(3+) polymer coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@ALG/Fe MNPs) with core/shell structure are prepared and used as heterogeneous Fenton nanocatalyst to degrade norfloxacin (NOF). The Fenton-like process based on Fe(3)O(4)@ALG/Fe shows much higher efficiency on NOF degradation. Compared with Fe(3)O(4) nanoparticle-H(2)O(2) system, NOF degradation in Fe(3)O(4)@AlG/Fe-H(2)O(2) system can be conducted in a wide pH range (pH 3.5-6.5) and independent on temperature. With 0.98 mM H(2)O(2) and 0.4 g L(-1) Fe(3)O(4)@ALG/Fe, 100% of NOF and 90% of TOC is removed within 60 min, and the fluorine element in NOF molecule changes into F(-) ions within 1 min, indicating that NOF degradation in this Fenton-like reaction is performed through direct defluorination pathway. XPS analysis shows that TOC removal in reaction solution mainly results from the adsorption of NOF degradation intermediates on catalyst. Due to the paramagneticity and high saturation magnetization of Fe(3)O(4)@ALG/Fe, the used catalyst with adsorbed NOF intermediate is collected from aqueous solution by applying an external magnetic field, leading to complete removal of NOF from water samples. As being composed of inorganic materials and biopolymer, Fe(3)O(4)@ALG/Fe MNPs are robust, thermo-stable, nontoxic and environmentally friendly. These attractive features endow Fe(3)O(4)@ALG/Fe as a potent Fenton-like catalyst for fluoroquinolones degradation.

Niu H; Dizhang; Meng Z; Cai Y

2012-08-01

86

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

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

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

2012-01-01

87

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

International Nuclear Information System (INIS)

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

2013-01-01

88

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

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

Zhao Baobao; Nan Zhaodong

2011-01-01

89

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

Science.gov (United States)

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

Zhao, Baobao; Nan, Zhaodong

2011-12-01

90

On the biocompatibility of Fe3O4 ferromagnetic nanoparticles with human blood cells.  

UK PubMed Central (United Kingdom)

Magnetic particles are currently applied to special biomedical and environmental applications owing to their unique magnetic, morphological and substance-carrying capabilities. Very recently we introduced Magnetically Assisted Hemodialysis (MAHD), an innovative therapeutic application of Ferromagnetic Nanoparticles (FNs) for the treatment of End-Stage Renal Disease (ESRD). MAHD can be employed for the selective and efficient removal of toxins that, although of high biological importance, they cannot be handled by current Hemodialysis strategies. This work is focused on evaluating the biocompatibility of Fe3O4 FNs with cells of donated human blood, namely red blood cells (RBCs), white blood cells (WBCs) and platelets (Plts). To that end, optical microscopy and atomic force microscopy were employed for the morphological examination of blood cells that were maturated under the presence of Fe3O4 FNs by means of mild incubation up to 120 min at T=20 degrees C. As a conclusion we have not detected noticeable interference between RBCs, WBCs and Pits with FNs for the maturation conditions and the extreme FNs concentrations examined in this work.

Stamopoulos D; Manios E; Gogola V; Niarchos D; Pissas M

2010-09-01

91

On the biocompatibility of Fe3O4 ferromagnetic nanoparticles with human blood cells.  

Science.gov (United States)

Magnetic particles are currently applied to special biomedical and environmental applications owing to their unique magnetic, morphological and substance-carrying capabilities. Very recently we introduced Magnetically Assisted Hemodialysis (MAHD), an innovative therapeutic application of Ferromagnetic Nanoparticles (FNs) for the treatment of End-Stage Renal Disease (ESRD). MAHD can be employed for the selective and efficient removal of toxins that, although of high biological importance, they cannot be handled by current Hemodialysis strategies. This work is focused on evaluating the biocompatibility of Fe3O4 FNs with cells of donated human blood, namely red blood cells (RBCs), white blood cells (WBCs) and platelets (Plts). To that end, optical microscopy and atomic force microscopy were employed for the morphological examination of blood cells that were maturated under the presence of Fe3O4 FNs by means of mild incubation up to 120 min at T=20 degrees C. As a conclusion we have not detected noticeable interference between RBCs, WBCs and Pits with FNs for the maturation conditions and the extreme FNs concentrations examined in this work. PMID:21133157

Stamopoulos, D; Manios, E; Gogola, V; Niarchos, D; Pissas, M

2010-09-01

92

Core-Shell Fe3O4 Polydopamine Nanoparticles Serve Multipurpose as Drug Carrier, Catalyst Support and Carbon Adsorbent.  

UK PubMed Central (United Kingdom)

We present the synthesis and multifunctional utilization of core-shell Fe3O4 polydopamine nanoparticles (Fe3O4@PDA NPs) to serve as the enabling platform for a range of applications including responsive drug delivery, recyclable catalyst support, and adsorbent. Magnetite Fe3O4 NPs formed in a one-pot process by the hydrothermal approach were coated with a polydopamine shell layer of ?20 nm in thickness. The as prepared Fe3O4@PDA NPs were used for the controlled drug release in a pH-sensitive manner via reversible bonding between catechol and boronic acid groups of PDA and the anticancer drug bortezomib (BTZ), respectively. 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 nanocatalysts exhibited high catalytic performance for the reduction of o-nitrophenol. Furthermore, the recovery and reuse of the catalyst was demonstrated 10 times without any detectible loss in activity. Finally, the PDA layers were converted into carbon to obtain Fe3O4@C and used as an adsorbent for the removal of Rhodamine B from an aqueous solution. The synergistic combination of unique features of PDA and magnetic nanoparticles establishes these core-shell NPs as a versatile platform for multiple applications.

Liu R; Guo Y; Odusote G; Qu F; Priestley RD

2013-09-01

93

Core-Shell Fe3O4 Polydopamine Nanoparticles Serve Multipurpose as Drug Carrier, Catalyst Support and Carbon Adsorbent.  

Science.gov (United States)

We present the synthesis and multifunctional utilization of core-shell Fe3O4 polydopamine nanoparticles (Fe3O4@PDA NPs) to serve as the enabling platform for a range of applications including responsive drug delivery, recyclable catalyst support, and adsorbent. Magnetite Fe3O4 NPs formed in a one-pot process by the hydrothermal approach were coated with a polydopamine shell layer of ?20 nm in thickness. The as prepared Fe3O4@PDA NPs were used for the controlled drug release in a pH-sensitive manner via reversible bonding between catechol and boronic acid groups of PDA and the anticancer drug bortezomib (BTZ), respectively. 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 nanocatalysts exhibited high catalytic performance for the reduction of o-nitrophenol. Furthermore, the recovery and reuse of the catalyst was demonstrated 10 times without any detectible loss in activity. Finally, the PDA layers were converted into carbon to obtain Fe3O4@C and used as an adsorbent for the removal of Rhodamine B from an aqueous solution. The synergistic combination of unique features of PDA and magnetic nanoparticles establishes these core-shell NPs as a versatile platform for multiple applications. PMID:24010676

Liu, Rui; Guo, Yunlong; Odusote, Gloria; Qu, Fengli; Priestley, Rodney D

2013-09-06

94

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

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Full Text Available Baoan Chen1*, Jian Cheng1*, Mingfang Shen1, Feng Gao1, Wenlin Xu2, et al1Department of Hematology;2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, P.R China, et al *These authors have contributed equally to this work.Abstract: Apoptosis is a common pathway that finally mediated the killing functions of anticancer drugs, which is an important cause of multidrug resistance (MDR). The aim of this study was to investigate the potential benefit of combination therapy with magnetic nanoparticle of Fe3O4 (MNP(Fe3O4)) and 5-bromotetrandrin (BrTet). Analysis of the apoptosis percentage showed that combination of daunorubicin (DNR) with either MNP(Fe3O4) or BrTet exerted a potent cytotoxic effect on K562/A02 cells, while MNP(Fe3O4) and BrTet cotreatment can synergistically enhance DNR-induced apoptosis. Importantly, we confirmed that the distinct synergism effect of that composite on reverse multidrug resistance may owe to the regulation of various proliferative and antiapoptotic gene products, including P53 and caspase-3. Thus our in vitro data strongly suggests a potential clinical application of MNP(Fe3O4) and BrTet combination on CML.Keywords: K562/A02 leukemic cells, multidrug resistance, magnetic nanoparticle of Fe3O4, 5-bromotetrandrine, apoptosis, P53, caspase-3

Baoan Chen; Jian Cheng; Mingfang Shen; Feng Gao; Wenlin Xu, et al 

2009-01-01

95

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

Science.gov (United States)

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

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

2013-06-01

96

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

UK PubMed Central (United Kingdom)

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

Khurshid H; Li W; Chandra S; Phan MH; Hadjipanayis GC; Mukherjee P; Srikanth H

2013-08-01

97

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

Science.gov (United States)

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

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

2013-08-01

98

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

Science.gov (United States)

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

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

2013-07-01

99

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

UK PubMed Central (United Kingdom)

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

Knappett BR; Abdulkin P; Ringe E; Jefferson DA; Lozano-Perez S; Rojas TC; Fernández A; Wheatley AE

2013-07-01

100

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

International Nuclear Information System (INIS)

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

2011-03-30

 
 
 
 
101

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

International Nuclear Information System (INIS)

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

2010-01-01

102

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

International Nuclear Information System (INIS)

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

2013-01-01

103

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

International Nuclear Information System (INIS)

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)

2012-04-27

104

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

UK PubMed Central (United Kingdom)

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

Zhang L; Zhu X; Jiao D; Sun Y; Sun H

2013-05-01

105

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

UK PubMed Central (United Kingdom)

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

Hu Y; Meng L; Niu L; Lu Q

2013-07-01

106

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

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

Gan N; Jin H; Li T; Zheng L

2011-01-01

107

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

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

M. Yousefi; P. Alimard

2013-01-01

108

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

International Nuclear Information System (INIS)

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

2006-11-28

109

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

International Nuclear Information System (INIS)

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

2012-02-15

110

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

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Full Text Available Baoan Chen1,*, Yiqiong Liang1,*, Weiwei Wu1, Jian Cheng1, Guohua Xia1, Feng Gao1, Jiahua Ding1, Chong Gao1, Zeye Shao1, Guohong Li1, Wenji Chen1, Wenlin Xu2, Xinchen Sun3, Lijie Liu4, Xiaomao Li5, Xuemei Wang61Department of Hematology; 3Department of Oncology, The Affiliated Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, People’s Republic of China; 4Institution of Physiology, Southeast University, Nanjing, People’s Republic of China; 5Department of Physics, University of Saarland, Saarbruechen, Germany; 6State Key Lab of Bioelectronics (Chien-Shiung Wu Laboratory), Southeast University, Nanjing, Peoples Republic of China; *These authors have contributed equally to this workAbstract: Gambogic acid (GA) has a significant anticancer effect on a wide variety of solid tumors. Recently, many nanoparticles have been introduced as drug-delivery systems to enhance the efficiency of anticancer drug delivery. The aim of this study was to investigate the potential benefit of combination therapy with GA and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4). The proliferation of K562 cells and their cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscope and flow cytometry, respectively. Furthermore, realtime polymerase chain reaction and Western blotting analyses were performed to examine gene transcription and protein expression, respectively. The results showed that MNPs-Fe3O4 dramatically enhanced GA-induced cytotoxicity and apoptosis in K562 cells. The typical morphological features of apoptosis treated with GA and MNPs-Fe3O4 were observed under an optical microscope and a fluorescence microscope, respectively. The transcription of caspase-3 and bax gene in the group treated with GA and MNPs-Fe3O4 was higher than that in the GA-alone group or MNPs-Fe3O4-alone group, but the transcription of bcl-2, nuclear factor-?B, and survivin degraded as did the expression of corresponding proteins in K562 cells. Our data suggests a potential clinical application of a combination of GA and MNPs-Fe3O4 in leukemia therapy.Keywords: gambogic acid, magnetic nanoparticles of Fe3O4, traditional Chinese medicine, K562 leukemia cells, apoptosis

Baoan Chen; Yiqiong Liang; Weiwei Wu; et al

2009-01-01

111

CaMoO4:Tb-Fe3O4 hybrid nanoparticles for luminescence and hyperthermia applications  

International Nuclear Information System (INIS)

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.

2013-02-05

112

CaMoO4:TbatFe3O4 hybrid nanoparticles for luminescence and hyperthermia applications  

Science.gov (United States)

We have prepared CaMoO4:TbatFe3O4 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.

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

2013-02-01

113

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stable magnetic nanofluids containing Fe3O4@Polypyrrole (PPy) nanoparticles (NPs) were prepared by using a facile and novel method, in which one-pot route was used. FeCl3·6H2O was applied as the iron source, and the oxidizing agent to produce PPy. Trisodium citrate (Na3cit) was used as the reducing ...

Zhao, Baobao; Nan, Zhaodong

114

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

Science.gov (United States)

In this study, humic acid-coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@HA MNPs) were synthesized using a chemical coprecipitation method and characterized in detail. The XRD analysis results showed that HA coating did not change the phase of Fe(3)O(4) cores. The TEM image suggested that Fe(3)O(4)@HA MNPs had nearly uniform size without the observation of aggregation. The Fe(3)O(4)@HA MNPs were stable in solution and could be easily separated from aqueous solution using a magnetic separation method. A batch technique was adopted to investigate the removal efficiency of Fe(3)O(4)@HA MNPs toward Eu(III) under various environmental conditions. The kinetic process of Eu(III) sorption on Fe(3)O(4)@HA MNPs reached equilibrium within nuclear waste management. PMID:23182180

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

2012-12-10

115

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

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Full Text Available Ying Wang1, Yuxiang Han1, Yingying Yang1, Jingci Yang1, Xiaonan Guo1, Jingnan Zhang1, Ling Pan1, Guohua Xia2, Baoan Chen21Department of Hematology, the 2nd Hospital of Hebei Medical University, People’s Republic of China; 2Department of Hematology, the Affiliated Zhongda Hospital, Medical School, Southeast University, Nanjing, People’s Republic of ChinaAbstract: The present study evaluated whether the magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) could enhance the activity of artesunate (ART), and to explore its potential mechanisms. Cytotoxicity of the copolymer of ART with MNPs-Fe3O4 on K562 cells was detected by MTT assay and the apoptosis rate of K562 cells was measured by flow cytometry. Protein expression levels of bcl-2, bax, bcl-rambo, caspase-3, and survivin in K562 cells were measured by Western blot. After being incubated with the copolymer of ART with MNPs-Fe3O4 for 48 hours, the growth inhibition rate of K562 cells was significantly increased compared with that of K562 cells treated with ART alone (P < 0.05), and the apoptosis rate of K562 cells was increased significantly compared with that of K562 cells treated with ART alone, suggesting that MNPs-Fe3O4 can enhance the activity of ART. Interestingly, the copolymer-induced cell death was attenuated by caspase inhibitor Z-VAD-FMK. Our results also showed that treatment with the copolymer of MNPs-Fe3O4 and ART increased the expression of bcl-2, bax, bcl-rambo, and caspase-3 proteins, and decreased the expression of survivin protein in K562 cells compared with ART treatment alone. These results suggest that MNPs-Fe3O4 can enhance ART-induced apoptosis, which may be related to the upregulation of bcl-rambo and downregulation of survivin.Keywords: magnetic nanoparticles, MNPs-Fe3O4, artesunate, K562 cells, apoptosis, bcl-rambo

Wang Y; Han Y; Yang Y; Yang J; Guo X; Zhang J; Pan L; Xia G; Chen B

2011-01-01

116

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

International Nuclear Information System (INIS)

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

2012-11-23

117

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

Science.gov (United States)

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

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

2012-11-01

118

Surface enhanced Raman spectroscopic studies on magnetic Fe3O4@AuAg alloy core-shell nanoparticles.  

UK PubMed Central (United Kingdom)

A facile approach has been developed to fabricate multifunctional Fe3O4@AuAg alloy core-shell nanoparticles, owning the magnetism of the core and the surface enhanced Raman spectroscopy (SERS) activities of the alloy shell. By changing the amount of HAuCl4 and AgNO3, Fe3O4@AuAg alloy nanoparticles with different component ratios of Au and Ag were successfully prepared. The surface plasmon resonance of the composition was linearly tuned in a wide range by varying the molar fraction of Ag and Au, suggesting the formation of AuAg alloy shell. SERS and magnetic enrichment effects were investigated by using thiophenol (TP) as the probe molecule. The SERS intensity was strongly dependent on the molar ratios of Au and Ag and the excitation line. Enrichment for the molecules with low concentration and on line SERS monitoring experiments were performed through combining the magnetism of the core and the SERS effect of the alloy shell. The results revealed that the magnetic enrichment efficiency was dramatically increased due to the strong magnetism of Fe3O4 core. In addition, the Fe3O4@AuAg nanoparticles were also used in the microfluidic chip to continuously detect different flowing solution in the channel. The detection time and amount of analyte were successfully decreased.

Sun HL; Xu MM; Guo QH; Yuan YX; Shen LM; Gu RA; Yao JL

2013-10-01

119

TPR Study of Core-Shell Fe@Fe3O4 Nanoparticles Supported on Activated Carbon and Carbon Nanotubes  

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Full Text Available Core-shell nanoparticles Fe@Fe3O4 supported on activated carbon (AC) and carbon nanotubes (CNTs) have been studied by H2 temperature-programmed reduction (TPR). Nanoparticles with size of 6.5 nm were synthesized by iron(II) oleate thermal decomposition and were supported on activated carbon and carbon nanotubes by colloid deposition method. The nanoparticles Fe@Fe3O4 are characterized by TEM and IR. Reduction of nanoparticles on AC starts at 140?C, whereas reduction of nanoparticles on CNTs starts at 200?C. Moreover, gasification of CNTs with methane releasing starts at 450?C, whereas gasification of AC is negligible at temperatures up to 800?C. All these findings illustrate a strong difference in the interaction between nanoparticles and the support material for AC and CNTs.

Igor Bychko; Yevhen Kalishyn; Peter Strizhak

2012-01-01

120

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

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

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

2008-01-01

 
 
 
 
121

Effect of Fe3O4-magnetic nanoparticles on acute exercise enhanced KCNQ1 expression in mouse cardiac muscle  

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Full Text Available Lijie Liu1, Baoan Chen2, Feixiang Teng1, Lijuan Shi1, Nan Jing2, Li Wang1, Ningna Chen2, Guohua Xia2, Xiaomao Li31Department of Physiology and Pharmacology, Medical School, Southeast University, Nanjing, People’s Republic of China; 2Department of Hematology, Affiliated Zhongda Hospital, Clinical Medical School, Southeast University, Nanjing, People’s Republic of China; 3Department of Physics, University of Saarland, Saarbruechen, GermanyAbstract: While the potential impact of magnetic nanoparticles (MNPs) has been widely explored in almost all medical fields, including cardiology, one question remains; that is whether MNPs interfere with cardiac physiological processes such as the expression and function of ion channels, especially in vivo. KCNQ1 channels are richly expressed in cardiac myocytes and are critical to the repolarization of cardiac myocytes. In this study, we evaluated the effects of Fe3O4-magnetic nanoparticles (MNPs-Fe3O4) on the expression of KCNQ1 in cardiac muscle of mice at rest and at different times following a single bout of swimming (SBS). Firstly, we demonstrated that the expression levels of KCNQ1 channels are significantly up-regulated in mice following a SBS by means of reverse transcription polymerase chain reaction (RT-PCR) and western-blot. After treating mice with normal saline or pure MNPs-Fe3O4 separately, we studied the potential effect of MNPs-Fe3O4 on the expression profile of KCNQ1 in mouse cardiac muscle following a SBS. A SBS increased the transcription of KCNQ1 at 3 hours post exercise (3PE) 164% ± 24% and at 12 hours post exercise (12PE) by 159% ± 23% (P < 0.05), and up-regulated KCNQ1 protein 161% ± 27% at 12PE (P < 0.05) in saline mice. In MNPs-Fe3O4 mice, KCNQ1 mRNA increased by 151% ± 14% and 147% ± 12% at 3 and 12 PE, respectively (P < 0.05). Meanwhile, an increase of 152% ± 14% in KCNQ1 protein was also detected at by 12PE. These results indicated that the administration of MNPs-Fe3O4 did not cause any apparent effects on the expression profile of KCNQ1 in rested or exercised mice cardiac muscle. Our studies suggest a novel path of KCNQ1 current adaptations in the heart during physical exercise and in addition provide some useful information for the biomedical application of MNPs which are imperative to advance nanomedicine.Keywords: KCNQ1, cardiac muscle, magnetic nanoparticles of Fe3O4

Lijie Liu; Baoan Chen,Feixiang Teng; et al

2010-01-01

122

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

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Full Text Available Magnetite, Fe3O4, is a promising anode material for lithium ion batteries due to its high theoretical capacity (924 mA h g?1), high density, low cost and low toxicity. However, its application as high capacity anodes is still hampered by poor cycling performance. To stabilize the cycling performance of Fe3O4 nanoparticles, composites comprising Fe3O4 nanoparticles and graphene sheets (GS) were fabricated. The Fe3O4/GS composite disks of mm dimensions were prepared by electrostatic self-assembly between negatively charged graphene oxide (GO) sheets and positively charged Fe3O4-APTMS [Fe3O4 grafted with (3-aminopropyl)trimethoxysilane (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.

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

2013-01-01

123

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

International Nuclear Information System (INIS)

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

2012-02-09

124

The real-time neurotoxicity analysis of Fe3O4 nanoparticles combined with daunorubicin for rat brain in vivo.  

UK PubMed Central (United Kingdom)

Drug safety for human body should be carefully studied for its potent clinical application. In this report, the neurotoxicity of anticancer drug daunorubicin (DNR) and the oleic acid-capped Fe3O4 nanoparticles (NPs) for rat brain was firstly explored by using the in vivo microdialysis. The results indicated that the anticancer drug DNR itself had the serious neurotoxicity for the rat brain. And this neurotoxicity was influenced through the concentration changes of amino acids. The concentration level of some excitatory amino acids (such as Glu) and some inhibiting amino acid (such as Gly) were considerably decreased while that of the excitatory amino acid Asp was remarkably increased. For the DNR conjugated with Fe3O4 NPs nanocomposites, the side effect of DNR was visibly cut down, and the time to cause the side neurotoxicity was apparently shortened. Thus, it is evident that compared with DNR alone, the DNR conjugated with Fe3O4 NPs nanocomposites have the better biocompatibility and bio-security for the relevant cancer treatment in vitro and in vivo. This raises the promising possibility of the application of these DNR conjugated with Fe3O4 NPs nanocomposites for the target cancer therapy.

Xu P; Li J; Chen B; Wang X; Cai X; Jiang H; Wang C; Zhang H

2012-06-01

125

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

Directory of Open Access Journals (Sweden)

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

Hongmei Jing; Jing Wang; Ping Yang; et al

2010-01-01

126

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

International Nuclear Information System (INIS)

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

2006-08-28

127

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 me...

Chen, Baoan; Sun, Qian; Wang, Xuemei; Gao, Feng; Dai, Yongyuan; Yin, Yan; Ding, Jiahua; Gao, Chong; Cheng, Jian; Li, Jingyuan

128

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

129

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

International Nuclear Information System (INIS)

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

2010-02-19

130

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

Science.gov (United States)

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

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

2010-02-01

131

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

UK PubMed Central (United Kingdom)

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

Mehdinia A; Roohi F; Jabbari A

2011-07-01

132

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

Scientific Electronic Library Online (English)

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

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

2013-01-01

133

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aims to evaluate the multidrug resistance (MDR) reversal activity by magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) and 5-bromotetrandrine (BrTet) MDR cell line K562/A02 solitarily or symphysially. The proliferation of K562 and K562/A02 cells and the cytotoxicity on peripheral blood mononuc...

Cheng, Jian; Wu, Weiwei; Chen, Bao-an; Gao, Feng; Xu, Wenlin; Gao, Chong; Ding, Jiahua; Sun, Yunyu; Song, Huihui; Bao, Wen

134

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aims to evaluate the potential benefit of combination therapy of 2-methoxyestradiol (2ME) and magnetic nanoparticles of Fe3O4 (MNPs-Fe3O4) on myelodysplastic syndrome (MDS) SKM-1 cells and its underlying mechanisms. The effect of the unique properties of tetraheptylammonium-capped MNPs-Fe...

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

135

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Chen, Bao-an; Lai, Bin-bin; Cheng, Jian; Xia, Guo-hua; Gao, Feng; Xu, Wen-lin; Ding, Jia-hua; Gao, Chong; Sun, Xin-chen

136

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

International Nuclear Information System (INIS)

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

2008-01-01

137

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

UK PubMed Central (United Kingdom)

In this study, humic acid-coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@HA MNPs) were synthesized using a chemical coprecipitation method and characterized in detail. The XRD analysis results showed that HA coating did not change the phase of Fe(3)O(4) cores. The TEM image suggested that Fe(3)O(4)@HA MNPs had nearly uniform size without the observation of aggregation. The Fe(3)O(4)@HA MNPs were stable in solution and could be easily separated from aqueous solution using a magnetic separation method. A batch technique was adopted to investigate the removal efficiency of Fe(3)O(4)@HA MNPs toward Eu(III) under various environmental conditions. The kinetic process of Eu(III) sorption on Fe(3)O(4)@HA MNPs reached equilibrium within <30 min. The fast sorption kinetics and high sorption amount were attributed to the plentiful surface sites provided by the surface-coated HA macromolecules. The Fe(3)O(4)@HA MNPs was able to remove ~99% of Eu(III) in aqueous solution at pH 8.5. Except for SO(4)(2-) anions, the coexisting electrolyte ions had no significant competition effects on the removal of Eu(III) by Fe(3)O(4)@HA MNPs. The obvious sorption-desorption hysteresis suggested that the removal of Eu(III) was dominated by inner-sphere surface complexation. The sorption isotherm agreed well with the Langmuir model, having a maximum sorption capacity of 6.95 × 10(-5) mol g(-1). The leaching test showed that the Eu(III)-loaded Fe(3)O(4)@HA colloids were capable to maintain high thermodynamic stability for long aging times. The findings herein suggested that Fe(3)O(4)@HA MNPs could be potentially used as a highly effective material for the enrichment and preconcentration of radionuclide Eu(III) or other trivalent lanthanides/actinides in geological repositories or in nuclear waste management.

Yang S; Zong P; Ren X; Wang Q; Wang X

2012-12-01

138

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

International Nuclear Information System (INIS)

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

2011-10-30

139

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

UK PubMed Central (United Kingdom)

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

Wang L; Su D; Zeng L; Liu N; Jiang L; Feng X; Neoh KG; Kang ET

2013-10-01

140

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

International Nuclear Information System (INIS)

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

2008-02-06

 
 
 
 
141

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

Science.gov (United States)

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

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

2013-07-31

142

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

Directory of Open Access Journals (Sweden)

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.

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

2013-01-01

143

Dependence of pH and surfactant effect in the synthesis of magnetite (Fe3O4) nanoparticles and its properties  

International Nuclear Information System (INIS)

Nanoparticles of Fe3O4 were synthesized by co-precipitation in an aqueous solution containing ferrous and ferric salts (1:2) at varying pH with ammonia as a base. It was found that the value of pH influences the reaction mechanism for the formation of Fe3O4. Furthermore, the addition of mercaptoethanol significantly reduced the crystalline size of Fe3O4 nanoparticles from 15.03 to 8.02 nm. X-ray diffraction (XRD) spectra revealed that the synthesized nanoparticles were ?-Fe2O3 or Fe3O4 phase. To further prove the composition of the product, as-prepared Fe3O4 were examined by X-ray photoelectron spectroscopy (XPS). Magnetic properties of the obtained particles were determined by vibrating sample magnetometer (VSM). Further analysis of the X-ray studies shows that while maintaining a pH value of 6 and 9 in a solution containing iron salts II and III ions produces ?-Fe2O3. Whereas a pH value of 11 produces magnetite (Fe3O4) phase. All of these results show that the pH has a major role in the observed phase formation of (Fe3O4) nanoparticles.

2010-01-01

144

Formation of magnetic nanotubes by the cooperative self-assembly of chiral amphiphilic molecules and Fe3O4 nanoparticles.  

UK PubMed Central (United Kingdom)

Single- and double-walled magnetic nanotubes are obtained in a one-step liquid phase reaction by the cooperative self-assembly of chiral amphiphiles and nanoparticles on cooling of heated mixtures of N-dodecanoyl-L-serine and Fe(3)O(4) nanoparticles in toluene. The nanotubes are composed of well-ordered, close-packed nanoparticle assemblies, and can be transformed into chiral magnetic nanostructures, such as helical coils, by subsequent calcination. The nanoparticle assemblies and their variations on calcination are attributed to the collective organization of the surfactant molecules adsorbed on the nanoparticles and the freely dispersed chiral molecules, and the dewetting effects guided by the primitive constitution of the chiral amphiphilic molecular assemblies.

Harada T; Simeon F; Vander Sande JB; Hatton TA

2010-10-01

145

3D nitrogen-doped graphene aerogel-supported Fe3O4 nanoparticles as efficient electrocatalysts for the oxygen reduction reaction.  

Science.gov (United States)

Three-dimensional (3D) N-doped graphene aerogel (N-GA)-supported Fe(3)O(4) nanoparticles (Fe(3)O(4)/N-GAs) as efficient cathode catalysts for the oxygen reduction reaction (ORR) are reported. The graphene hybrids exhibit an interconnected macroporous framework of graphene sheets with uniform dispersion of Fe(3)O(4) nanoparticles (NPs). In studying the effects of the carbon support on the Fe(3)O(4) NPs for the ORR, we found that Fe(3)O(4)/N-GAs show a more positive onset potential, higher cathodic density, lower H(2)O(2) yield, and higher electron transfer number for the ORR in alkaline media than Fe(3)O(4) NPs supported on N-doped carbon black or N-doped graphene sheets, highlighting the importance of the 3D macropores and high specific surface area of the GA support for improving the ORR performance. Furthermore, Fe(3)O(4)/N-GAs show better durability than the commercial Pt/C catalyst. PMID:22624986

Wu, Zhong-Shuai; Yang, Shubin; Sun, Yi; Parvez, Khaled; Feng, Xinliang; Müllen, Klaus

2012-05-29

146

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

Science.gov (United States)

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

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

2013-07-01

147

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

Science.gov (United States)

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

Widanarto, W.; Sahar, M. R.; Ghoshal, S. K.; Arifin, R.; Rohani, M. S.; Hamzah, K.

2013-01-01

148

Synthesis of Fe3O4-ZnS/AgInS2 composite nanoparticles using a hydrophobic interaction.  

UK PubMed Central (United Kingdom)

Magnetic nanoparticles and fluorescent quantum dots (QDs) can make many effective applications in biomedical system. Here, we demonstrated one way of synthetic method and its surface modification to use for biomedical applications. Fe3O4 nanoparticles are well known as magnetic materials and its magnetic property can be used in magnetic resonance imaging (MRI), cell detection. QDs as a fluorescent probes, make cell labeling and in vivo imaging possible. ZnS/AgInS2 QDs have a lower toxicity than other QDs (CdSe, CdTe, CdS). We combined two nanoparticles by hydrophobic interaction in their ligands. The prepared fluorescent magnetic composite particles were modified with CTAB-TEOS. The surface modified composite has a low cytotoxicity and these biocompatible particles will provide many possibilities in biomedical system.

Choi KS; Bang BK; Bae PK; Kim YR; Kim CH

2013-03-01

149

Synthesis of Fe3O4-ZnS/AgInS2 composite nanoparticles using a hydrophobic interaction.  

Science.gov (United States)

Magnetic nanoparticles and fluorescent quantum dots (QDs) can make many effective applications in biomedical system. Here, we demonstrated one way of synthetic method and its surface modification to use for biomedical applications. Fe3O4 nanoparticles are well known as magnetic materials and its magnetic property can be used in magnetic resonance imaging (MRI), cell detection. QDs as a fluorescent probes, make cell labeling and in vivo imaging possible. ZnS/AgInS2 QDs have a lower toxicity than other QDs (CdSe, CdTe, CdS). We combined two nanoparticles by hydrophobic interaction in their ligands. The prepared fluorescent magnetic composite particles were modified with CTAB-TEOS. The surface modified composite has a low cytotoxicity and these biocompatible particles will provide many possibilities in biomedical system. PMID:23755598

Choi, Kang Sik; Bang, Bo Keuk; Bae, Pan Kee; Kim, Yong-Rok; Kim, Chang Hae

2013-03-01

150

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

Science.gov (United States)

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

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

2013-05-01

151

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

UK PubMed Central (United Kingdom)

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.

Yin Y; Liu C; Wang B; Yu S; Chen K

2013-05-01

152

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

UK PubMed Central (United Kingdom)

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

Chen R; Chai L; Li Q; Shi Y; Wang Y; Mohammad A

2013-10-01

153

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

Science.gov (United States)

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

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

2013-05-04

154

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

Science.gov (United States)

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

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

2008-03-01

155

Interspacing dependence of spin-dependent variable range hopping for cold-pressed Fe3O4 nanoparticles  

Science.gov (United States)

The influence of the contact between monodisperse Fe3O4 nanoparticles (NPs) on the spin-dependent transport mechanism has been investigated by only changing the cold-press pressures from 20.0 MPa to 5.0 GPa. For the sample cold-pressed under 20.0 MPa, the temperature dependence of resistivity ?-T curve is best fitted by the log ? ~ T-1/2 relation, suggesting the Efros's variable range hopping (VRH) mechanism, while the ?-T curves of the samples cold-pressed under 1.0 GPa to 5.0 GPa can be best fit with the relation of log ? ~ T-1/4, revealing the Mott's VRH mechanism. The different mechanisms are related to the interspacing dependence of charging energy and exchange energy between NPs. Monte Carlo simulations indicated that the charging energy plays a dominant role in the former mechanism, while the spin-dependent exchange energy is dominated in the latter one.

Song, Ning-Ning; Yang, Hai-Tao; Li, Fei-Ye; Li, Zi-An; Han, Wei; Ren, Xiao; Luo, Yi; Wang, Xian-Cheng; Jin, Chang-Qing; Zhang, Xiang-Qun; Cheng, Zhao-Hua

2013-05-01

156

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

International Nuclear Information System (INIS)

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

2011-01-01

157

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

Directory of Open Access Journals (Sweden)

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-?-human chorionic gonadotropin (HCG) nanoparticles as a gene vector for cellular transfections.Study design: Fe3O4-dextran-anti-?-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-?-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-?-HCG nanoparticles was examined by agarose gel electrophoresis. The ability of Fe3O4-dextran-anti-?-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-?-HCG nanoparticles was <37.5 µg/mL. Fe3O4-dextran nanoparticles have a satisfactory potential to combine with ?-HCG antibody. Agarose gel electrophoresis analysis of binding experiments showed that after treatment with sodium periodate, Fe3O4-dextran-anti-?-HCG nanoparticles have a satisfactory potential to absorb DNA, and the protection experiment showed that nanoparticles can effectively protect DNA from DNase I digestion. Aldehyde Fe3O4-dextran-anti-?-HCG nanoparticles can transfect reporter genes, and the transfection efficiency of these nanoparticles is greater than that of liposomes (P <0.05). Fe3O4-dextran-anti-?-HCG nanoparticles can concentrate in choriocarcinoma cells and in transplanted choriocarcinoma tumors.Conclusions: The results confirm that Fe3O4-dextran-anti-?-HCG nanoparticles have potential as a secure, effective, and choriocarcinoma-specific targeting gene vector.Keywords: magnetic nanoparticles, Fe3O4-dextran-anti-?-HCG, choriocarcinoma, targeting vector, gene vector

Cai Jingting; Liu Huining; et al

2011-01-01

158

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 nanomater...

Chockalingam Ashwin; Babu Heman; Chittor Raghuraman; Tiwari Jai

159

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

UK PubMed Central (United Kingdom)

In this work, a facile approach was successfully developed for in situ catalyzing Au nanoparticles loaded on Fe3O4@SiO2 magnetic nanospheres via Sn(2+) 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.

Zheng J; Dong Y; Wang W; Ma Y; Hu J; Chen X; Chen X

2013-06-01

160

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

Science.gov (United States)

In this work, a facile approach was successfully developed for in situ catalyzing Au nanoparticles loaded on Fe3O4@SiO2 magnetic nanospheres via Sn(2+) 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. PMID:23624783

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

2013-04-26

 
 
 
 
161

Solution-Processed Fe3O4 Magnetic Nanoparticle Thin Film Aligned by an External Magnetostatic Field as a Hole Extraction Layer for Polymer Solar Cells.  

UK PubMed Central (United Kingdom)

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

Wang K; Ren H; Wang H; Yi C; Huang L; Zhang HL; Karim A; Gong X; Liu C

2013-09-01

162

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

Science.gov (United States)

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.

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

2013-05-01

163

Solution-Processed Fe3O4 Magnetic Nanoparticle Thin Film Aligned by an External Magnetostatic Field as a Hole Extraction Layer for Polymer Solar Cells.  

UK PubMed Central (United Kingdom)

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

Wang K; Ren H; Yi C; Liu C; Wang H; Huang L; Zhang H; Karim A; Gong X

2013-10-01

164

Solution-Processed Fe3O4 Magnetic Nanoparticle Thin Film Aligned by an External Magnetostatic Field as a Hole Extraction Layer for Polymer Solar Cells.  

Science.gov (United States)

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

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

2013-10-08

165

Surface anisotropy of a Fe3O4 nanoparticle: A simulation approach  

International Nuclear Information System (INIS)

[en] On the basis of a three-dimensional classical Heisenberg model with nearest magnetic neighbor interactions, and using a Monte Carlo-Metropolis dynamics, we study the magnetic behavior of a 5 nm diameter magnetite nanoparticle as a function of temperature. The nanoparticle is built by taken into account the inverse spinel structure of a stoichiometric magnetite, the valence of the iron ions (Fe3+ A, Fe3+ B, Fe2+ B where A and B stand for tetrahedral and octahedral sites, respectively) as well as the different involved coordination numbers and superexchange integrals. The employed Hamiltonian includes coupling interactions between Fe ions through the integrals J AA, J AB and J BB, a Neel's surface anisotropy term applied to surface ions, and cubic magnetocrystalline anisotropy for those ions belonging to the core of the nanoparticle. Results reveal a strong influence of surface anisotropy, depending on its sign and magnitude, upon the total magnetization at low temperatures. Such results, which are summarized in a proposal of phase diagram, reveal the onset of spin structures different from a single-domain state. Differences in the thermal behavior respect to a bulk magnetite are also addressed and discussed

2007-09-01

166

Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping  

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-10-22

167

Synthesis and characterization of PVP-functionalized superparamagnetic Fe3O4 nanoparticles as an MRI contrast agent  

Directory of Open Access Journals (Sweden)

Full Text Available The magnetite (Fe3O4) nanoparticles (MNPs) coated with poly(N-vinyl pyrrolidone) (PVP) via covalent bonds were prepared as T2 contrast agent for magnetic resonance imaging (MRI). The surface of MNPs was first coated with 3-(trimethoxysilyl) propyl methacrylate (silan A) by a silanization reaction to introduce reactive vinyl groups onto the surface, then poly(N-vinyl pyrrolidone) was grafted onto the surface of modified-MNPs via surface-initiated radical polymerization. The obtained nanoparticles were characterized by FT-IR (Fourier transform infrared spectroscopy), XRD (X-ray diffraction), TEM (transmission electron microscopy), VSM (vibrating sample magnetometer), and TGA (thermogravimetric analysis). The MNPs had an average size of 14 nm and exhibited superparamagnetism and high saturation magnetization at room temperature. T2-weighted MRI images of PVP-grafted MNPs showed that the magnetic resonance signal is enhanced significantly with increasing nanoparticle concentration in water. The r1 and r2 values per millimole Fe, and r2/r1 value of the PVP-grafted MNPs were calculated to be 2.6 , 72.1, and 28.1(mmol/l)–1•s–1, respectively. These results indicate that the PVP-grafted MNPs have great potential for application in MRI as a T2 contrast agent.

2010-01-01

168

Fe3O4 nanoparticles-enhanced SPR sensing for ultrasensitive sandwich bio-assay.  

UK PubMed Central (United Kingdom)

Magnetic nanoparticles (MNPs) have been receiving increasing attention because of its great potentials in bioseparation. However, the separation products are difficult to be detected by general method due to their extremely small size. Here, we demonstrate that MNPs can greatly enhance the signal of surface plasmon resonance spectroscopy (SPR). Features of MNPs-aptamer conjugates as a powerful amplification reagent for ultrasensitive immunoassay are reported in this work for the first time. In order to evaluate the sensing ability of MNPs-aptamer conjugates as an amplification reagent, a sandwich SPR sensor is constructed by using thrombin as model analyte. Thrombin, captured by immobilized anti-thrombin aptamer on SPR gold film, is sensitively detected by SPR spectroscopy with a lowest detection limit of 0.017 nM after MNPs-aptamer conjugates is used as amplification reagent. At the same time, the excellent selectivity of the present biosensor is also confirmed by using three kinds of proteins (BSA, human IgM and human IgE) as controls. These results confirm that MNPs is a powerful sandwich element and an excellent amplification reagent for SPR based sandwich immunoassay and SPR has a great potential for the detection of MNPs-based bioseparation products.

Wang J; Zhu Z; Munir A; Zhou HS

2011-05-01

169

Labeling Primary Amine Groups in Peptides and Proteins with N-Hydroxysuccinimidyl Ester Modified Fe3O4@SiO2 Nanoparticles Containing Cleavable Disulfide-Bond Linkers.  

UK PubMed Central (United Kingdom)

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

Patil US; Qu H; Caruntu D; O'Connor CJ; Sharma A; Cai Y; Tarr MA

2013-09-01

170

Labeling Primary Amine Groups in Peptides and Proteins with N-Hydroxysuccinimidyl Ester Modified Fe3O4@SiO2 Nanoparticles Containing Cleavable Disulfide-Bond Linkers.  

Science.gov (United States)

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

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

2013-08-28

171

A simplified method for synthesis of Fe3O4@PAA nanoparticles and its application for the removal of basic dyes  

Science.gov (United States)

A simplified method for synthesis of polyacrylic acid-bound iron oxide magnetic nanoparticles (Fe3O4@PAA NPs) was reported. The as-prepared nanoparticles were characterized by TEM, FT-IR, VSM and XRD. Characterization results indicated that PAA was successfully introduced onto the surface of Fe3O4 and did not cause any changes in magnetic property. The Fe3O4@PAA NPs were used to adsorb rhodamine 6G (R6G) as a model basic dye pollutant from aqueous solution. Kinetics data and adsorption isotherms were better fitted by pseudo-second-order kinetic model and Langmuir isotherm, respectively. The adsorption equilibrium could be reached at about 20 min, showing that the as-prepared adsorbent exhibited extremely rapid adsorption rate. The aqueous solution of the Yellow River was chosen as the test sample, and the results showed that the magnetic adsorbent was efficient for the removal of the basic dye in the real sample.

Xu, Yin-Yin; Zhou, Min; Geng, Hui-Juan; Hao, Jun-Jie; Ou, Qian-Qian; Qi, Sheng-Da; Chen, Hong-Li; Chen, Xing-Guo

2012-02-01

172

Facile One-Pot Synthesis of Fe3O4@Au Composite Nanoparticles for Dual-Mode MR/CT Imaging Applications.  

Science.gov (United States)

A facile one-pot hydrothermal approach to synthesizing Fe3O4@Au composite nanoparticles (CNPs) for dual-mode magnetic resonance (MR) and computed tomography (CT) imaging applications is reported. In this work, polyethyleneimine (PEI) partially modified with poly(ethylene glycol) monomethyl ether (mPEG) was used as a stabilizer to form gold NPs (mPEG-PEI.NH2-Au NPs) with the assistance of sodium borohydride reduction. The mPEG-PEI.NH2-Au NPs were then mixed with iron(II) salt in a basic aqueous solution followed by treatment under an elevated temperature and pressure. This hydrothermal process led to the formation of Fe3O4@Au-mPEG-PEI.NH2 CNPs. The remaining PEI amine groups were finally acetylated to reduce the surface positive charge of the CNPs. The formed Fe3O4@Au-mPEG-PEI.NHAc (Fe3O4@Au) CNPs were characterized via different techniques. The combined in vitro cell viability assay, cell morphology observation, flow cytometry, and hemolysis assay data show that the formed Fe3O4@Au CNPs are noncytotoxic and hemocompatible in the given concentration range. MR and CT imaging data reveal that the formed Fe3O4@Au CNPs have a relatively high r2 relaxivity (146.07 mM(-1 )s(-1)) and good X-ray attenuation property, which enables their uses as contrast agents for MR imaging of mouse liver and CT imaging of rat liver and aorta. The Fe3O4@Au CNPs developed via the facile one-pot approach may have promising potential for the dual-mode MR/CT imaging of different biological systems. PMID:24063810

Li, Jingchao; Zheng, Linfeng; Cai, Hongdong; Sun, Wenjie; Shen, Mingwu; Zhang, Guixiang; Shi, Xiangyang

2013-10-08

173

Facile One-Pot Synthesis of Fe3O4@Au Composite Nanoparticles for Dual Mode MR/CT Imaging Applications.  

UK PubMed Central (United Kingdom)

A facile one-pot hydrothermal approach to synthesizing Fe3O4@Au composite nanoparticles (CNPs) for dual mode magnetic resonance (MR) and computed tomography (CT) imaging applications is reported. In this work, polyethyleneimine (PEI) partially modified with polyethylene glycol monomethyl ether (mPEG) was used as a stabilizer to form gold NPs (mPEG-PEI.NH2-Au NPs) with the assistance of sodium borohydride reduction. Then, the mPEG-PEI.NH2-Au NPs were mixed with iron (II) salt in a basic aqueous solution, followed by treatment under an elevated temperature and pressure. This hydrothermal process led to the formation of Fe3O4@Au-mPEG-PEI.NH2 CNPs. The remaining PEI amine groups were finally acetylated to reduce the surface positive charge of the CNPs. The formed Fe3O4@Au-mPEG-PEI.NHAc (Fe3O4@Au) CNPs were characterized via different techniques. Combined in vitro cell viability assay, cell morphology observation, flow cytometry, and hemolysis assay data show that the formed Fe3O4@Au CNPs are non-cytotoxic and hemocompatible in the given concentration range. MR and CT imaging data reveal that the formed Fe3O4@Au CNPs have a relatively high r2 relaxivity (146.07 mM-1s-1) and good X-ray attenuation property, which enables their uses as contrast agents for MR imaging of mouse liver and CT imaging of rat liver and aorta. The Fe3O4@Au CNPs developed via the facile one-pot approach may have a promising potential for dual mode MR/CT imaging of different biological systems.

Li J; Zheng L; Cai H; Sun W; Shen M; Zhang G; Shi X

2013-09-01

174

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

International Nuclear Information System (INIS)

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

2011-01-01

175

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

Science.gov (United States)

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

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

2011-02-01

176

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

International Nuclear Information System (INIS)

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

2011-02-04

177

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

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

Xia G; Chen B; Ding J; Gao C; Lu H; Shao Z; Gao F; Wang X

2011-01-01

178

A noninvasive method to determine the fate of Fe(3)O(4) nanoparticles following intravenous injection using scanning SQUID biosusceptometry.  

UK PubMed Central (United Kingdom)

Magnetic nanoparticles (MNPs) of Fe(3)O(4) have been widely applied in many medical fields, but few studies have clearly shown the outcome of particles following intravenous injection. We performed a magnetic examination using scanning SQUID biosusceptometry (SSB). Based on the results of SSB analysis and those of established in vitro nonmagnetic bioassays, this study proposes a model of MNP metabolism consisting of an acute metabolic phase with an 8 h duration that is followed by a chronic metabolic phase that continues for 28 d following MNP injection. The major features included the delivery of the MNPs to the heart and other organs, the biodegradation of the MNPs in organs rich with macrophages, the excretion of iron metabolites in the urine, and the recovery of the iron load from the liver and the spleen. Increases in serum iron levels following MNP injection were accompanied by increases in the level of transferrin in the serum and the number of circulating red blood cells. Correlations between the in vivo and in vitro test results indicate the feasibility of using SSB examination for the measurement of MNP concentrations, implying future clinical applications of SSB for monitoring the hematological effects of MNP injection.

Tseng WK; Chieh JJ; Yang YF; Chiang CK; Chen YL; Yang SY; Horng HE; Yang HC; Wu CC

2012-01-01

179

Electrogenerated chemiluminescence immunosensor for Bacillus thuringiensis Cry1Ac based on Fe3O4@Au nanoparticles.  

UK PubMed Central (United Kingdom)

A highly sensitive electrochemiluminescence (ECL) immunosensor for Cry1Ac was fabricated. The primary antibody anti-Cry1Ac was immobilized onto core-shell structural Fe(3)O(4)@Au nanoparticles. The antigen and glucose-oxidase-labeled secondary antibody were then successively combined to form sandwich-type immunocomplexes through a specific interaction. The magnetic particles loaded with sandwich immune complexes were attracted to a magnet-controlled glass carbon electrode (GCE) by an external magnet applied on top of the GCE. ECL was generated by the reaction between luminol and hydrogen peroxide derived from the enzymatic reaction in the presence of glucose. The sensors exhibited high sensitivity and a wide linear range for Bacillus thuringiensis Cry1Ac detection from 0 to 6 ng/mL, as well as a detection limit of 0.25 pg/mL (S/N = 3). The sensor is one of the most sensitive sensors for Cry1Ac, which can be easily renewed and conveniently used.

Li J; Xu Q; Wei X; Hao Z

2013-02-01

180

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

International Nuclear Information System (INIS)

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

2011-10-29

 
 
 
 
181

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnetically separable Fe3O4 nanoparticles supply environmentally friendly procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene and 1,8-dioxo-octahydro-xanthene derivatives. These compounds were obtained in high yields and short reaction times by the reaction of dimedone and 2-naphtho...

Ghasemzadeh Ali Mohammad; Safaei-Ghomi Javad; Zahedi Safura

182

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

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Full Text Available Baoan Chen1,* Jian Cheng1,* Yanan Wu1, Feng Gao1, Wenlin Xu2, et al 1Department of Hematology;2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, PR China *These authors have contributed equally to this workAbstract: In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4) combined with daunorubicin (DNR) in vivo. Two subclones of K562 and K562/A02 cells were inoculated subcutaneously into the back of athymic nude mice (1 × 107 cells/each) respectively to establish leukemia xenograft models. Drug-resistant and sensitive tumor-bearing nude mice were assigned randomly into five groups which were treated with normal saline; DNR; NP-Fe3O4 combined with DNR; 5-BrTet combined with DNR; 5-BrTet and MNP-Fe3O4 combined with DNR, respectively. The incidence of formation, growth characteristics, weight, and volume of tumors were observed. The histopathologic examination of tumors and organs were detected. For resistant tumors, the protein levels of Bcl-2, and BAX were detected by Western blot. Bcl-2, BAX, and caspase-3 genes were also detected. For K562/A02 cells xenograft tumors, 5-BrTet and MNP-Fe3O4 combined with DNR significantly suppressed growth of tumor. A histopathologic examination of tumors clearly showed necrosis of the tumors. Application of 5-BrTet and MNP-Fe3O4 inhibited the expression of Bcl-2 protein and upregulated the expression of BAX and caspase-3 proteins in K562/A02 cells xenograft tumor. It is concluded that 5-BrTet and MNP-Fe3O4 combined with DNR had a significant tumor-suppressing effect on a MDR leukemia cells xenograft model.Keywords: 5-bromotetrandrine, magnetic nanoparticle of Fe3O4, multidrug-resistance, xenograft model

Baoan Chen; Jian Cheng; Yanan Wu; Feng Gao; Wenlin Xu; et al

2009-01-01

183

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

UK PubMed Central (United Kingdom)

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

Zhang X; Wang H; Yang C; Du D; Lin Y

2013-03-01

184

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

Science.gov (United States)

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

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

2012-10-12

185

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-03-15

186

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

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

Baoan Chen; Qian Sun; Xuemei Wang; Feng Gao; Yongyuan Dai; et al

2008-01-01

187

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

International Nuclear Information System (INIS)

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

2013-04-15

188

Barium alginate caged Fe3O4@C18 magnetic nanoparticles for the pre-concentration of polycyclic aromatic hydrocarbons and phthalate esters from environmental water samples.  

UK PubMed Central (United Kingdom)

The hydrophobic octadecyl (C(18)) functionalized Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@C(18)) were caged into hydrophilic barium alginate (Ba(2+)-ALG) polymers to obtain a novel type of solid-phase extraction (SPE) sorbents, and the sorbents were applied to the pre-concentration of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) pollutants from environmental water samples. The hydrophilicity of the Ba(2+)-ALG cage enhances the dispersibility of sorbents in water samples, and the superparamagnetism of the Fe(3)O(4) core facilitates magnetic separation. With the magnetic SPE technique based on the Fe(3)O(4)@C(18)@Ba(2+)-ALG sorbents, it requires only 30 min to extract trace levels of analytes from 500 mL water samples. After the eluate is condensed to 0.5 mL, concentration factors for both phenanthrene and di-n-propyl-phthalate are over 500, while for other analytes are about 1000. The recoveries of target compounds are independent of salinity and solution pH under testing conditions. Under optimized conditions, the detection limits for phenanthrene, pyrene, benzo[a]anthracene, and benzo[a]pyrene are 5, 5, 3, and 2 ng L(-1), and for di-n-propyl-phthalate, di-n-butyl-phthalate, di-cyclohexyl-phthalate, and di-n-octyl-phthalate are 36, 59, 19, and 36 ng L(-1), respectively. The spiked recoveries of several real water samples for PAHs and PAEs are in the range of 72-108% with relative standard deviations varying from 1% to 9%, showing good accuracy of the method. The advantages of the new SPE method include high extraction efficiency, short analysis time and convenient extraction procedure. To the best of our knowledge, it is unprecedented that hydrophilic Ba(2+)-ALG polymer caged Fe(3)O(4)@C(18) magnetic nanomaterial is used to extract organic pollutants from large volumes of water samples.

Zhang S; Niu H; Cai Y; Shi Y

2010-04-01

189

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

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

Liu YC; Wu PC; Shieh DB; Wu SN

2012-01-01

190

Reversal of multidrug resistance by magnetic chitosan-Fe3O4 nanoparticle-encapsulated MDR1 siRNA in glioblastoma cell line.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the reversal effects of MDR1 gene on multidrug resistance in the glioblastoma cell line BT325 by magnetic chitosan-Fe3O4 nanoparticle-encapsulated MDR1 siRNA. METHODS: The shRNA expression vector was constructed and the recombinant plasmids were cloned. Magnetic chitosan-Fe3O4 nanoparticles were prepared and the encapsulation rate was determined. After transfection, the BT325 cells were cultured to assay the transfection efficiency. The changing of MDR1 mRNA level and P-gp protein was evaluated. And the sensitivity to different chemotherapeutic drugs was assessed in BT325-siRNA transfected cell and untransfected cell by IC50 values. RESULTS: The MDR1 RNAi plasmid was successfully designed and preparation. The encapsulation efficiency of the magnetic chitosan-Fe3O4 nanoparticle was 98-99%. The transfection efficiency of the siRNA-nanoparticles in BT325 cells was 70-80%. And the MDR1 mRNA levels were downregulated by reverse transcription (RT)-PCR assay. Furthermore, the results of P-gp protein expression decreased on immunocytochemical assay, Western blot and flow cytometry compared with control group. The IC50 values of DOX and VCR were decreased between the transfected cell and normal BT325 cell. CONCLUSION: After targeted transfection of the glioblastoma cell line with magnetic chitosan-Fe3O4 nanoparticle-encapsulated MDR1 siRNA, the expression of MDR1 at both the mRNA and protein level decreased, which increased sensitivity to chemotherapy in vitro. It might provide a basis for investigation of the mechanism involved in multidrug resistance in glioma.

Zhao P; Wang H; Gao H; Li C; Zhang Y

2013-10-01

191

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

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

Huang KW; Chieh JJ; Horng HE; Hong CY; Yang HC

2012-01-01

192

Cyclodextrin-functionalized Fe3O4@TiO2: reusable, magnetic nanoparticles for photocatalytic degradation of endocrine-disrupting chemicals in water supplies.  

UK PubMed Central (United Kingdom)

Water-dispersible, photocatalytic Fe3O4@TiO2 core-shell magnetic nanoparticles have been prepared by anchoring cyclodextrin cavities to the TiO2 shell, and their ability to capture and photocatalytically destroy endocrine-disrupting chemicals, bisphenol A and dibutyl phthalate, present in water, has been demonstrated. The functionalized nanoparticles can be magnetically separated from the dispersion after photocatalysis and hence reused. Each component of the cyclodextrin-functionalized Fe3O4@TiO2 core-shell nanoparticle has a crucial role in its functioning. The tethered cyclodextrins are responsible for the aqueous dispersibility of the nanoparticles and their hydrophobic cavities for the capture of the organic pollutants that may be present in water samples. The amorphous TiO2 shell is the photocatalyst for the degradation and mineralization of the organics, bisphenol A and dibutyl phthalate, under UV illumination, and the magnetism associated with the 9 nm crystalline Fe3O4 core allows for the magnetic separation from the dispersion once photocatalytic degradation is complete. An attractive feature of these "capture and destroy" nanomaterials is that they may be completely removed from the dispersion and reused with little or no loss of catalytic activity.

Chalasani R; Vasudevan S

2013-05-01

193

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

UK PubMed Central (United Kingdom)

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

Sedlák M; Bhosale DS; Beneš L; Palar?ík J; Kalendová A; Královec K; Imramovský A

2013-08-01

194

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

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

Ghasemzadeh Ali Mohammad; Safaei-Ghomi Javad; Zahedi Safura

2013-01-01

195

Synthesis, structure and magnetic properties of porous magnetic composite, based on MCM-41 molecular sieve with Fe3O4 nanoparticles  

International Nuclear Information System (INIS)

[en] Porous magnetic composites were prepared by the synthesis of molecular sieve MCM-41 in the presence of Fe3O4 nanoparticles with average diameter of 15 nm. Nanoparticles were captured by porous silica matrix MCM-41, which resulted in their incorporation, as it was confirmed by TEM, SEM and X-ray diffraction. The materials possessed high surface area (392-666 m2 g-1), high pore volume (0.39-0.73 cm3 g-1) along with high magnetic response (M S up to 28.4 emu g-1 at 300 K). Calcination of samples resulted in partial oxidation of Fe3O4 to ?-Fe2O3. The influence of nanoparticles content on sorption and magnetic properties of the composites was shown. No hysteresis was found for the samples at 300 K; at 5 K, H C was in the range 370-385 G for non-calcinated samples and 350-356 G for calcinated ones. - Graphical abstract: Schematic presentation of MCM-41/Fe3O4 composite

2006-01-01

196

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

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

Jian Cheng; Weiwei Wu; Bao-an Chen; et al

2009-01-01

197

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

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

Bao-an Chen; Bin-bin Lai; Jian Cheng; et al

2009-01-01

198

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

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

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

2013-09-01

199

A novel europium-sensitive fluorescent nano-chemosensor based on new functionalized magnetic core-shell Fe3O4@SiO2 nanoparticles.  

UK PubMed Central (United Kingdom)

A novel Eu(3+)-sensitive fluorescent chemosensor is introduced. It is based on magnetic core-shell silica nanoparticle which is functionalized by Cinchonidine (CD-Fe3O4@SiO2). The nano-chemosensor was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible absorption and fluorescence emission. The fluorescent nano-chemosensor shows a selective interaction with Eu(3+) ion. Fluorescence studies revealed that the emission intensity of the functionalized magnetic core-shell silica nanoparticles (CD-Fe3O4@SiO2 NPs) increases significantly by addition of various concentrations of Eu(3+) ion. While in case of mono, di, and other trivalent cations, weak changes or either no changes in intensity were observed. The enhancement in fluorescence intensity of nano-chemosensor is because of the strong covalent binding of Eu(3+) ion to CD-Fe3O4@SiO2 NPs with a large binding constant value of 1.7×10(5)molL(-1).

Ganjali MR; Hosseini M; Khobi M; Farahani S; Shaban M; Faridbod F; Shafiee A; Norouzi P

2013-10-01

200

A novel europium-sensitive fluorescent nano-chemosensor based on new functionalized magnetic core-shell Fe3O4@SiO2 nanoparticles.  

Science.gov (United States)

A novel Eu(3+)-sensitive fluorescent chemosensor is introduced. It is based on magnetic core-shell silica nanoparticle which is functionalized by Cinchonidine (CD-Fe3O4@SiO2). The nano-chemosensor was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-visible absorption and fluorescence emission. The fluorescent nano-chemosensor shows a selective interaction with Eu(3+) ion. Fluorescence studies revealed that the emission intensity of the functionalized magnetic core-shell silica nanoparticles (CD-Fe3O4@SiO2 NPs) increases significantly by addition of various concentrations of Eu(3+) ion. While in case of mono, di, and other trivalent cations, weak changes or either no changes in intensity were observed. The enhancement in fluorescence intensity of nano-chemosensor is because of the strong covalent binding of Eu(3+) ion to CD-Fe3O4@SiO2 NPs with a large binding constant value of 1.7×10(5)molL(-1). PMID:24054591

Ganjali, Mohammad Reza; Hosseini, Morteza; Khobi, Mehdi; Farahani, Shima; Shaban, Masoom; Faridbod, Farnoush; Shafiee, Abbas; Norouzi, Parviz

2013-04-30

 
 
 
 
201

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

UK PubMed Central (United Kingdom)

ABSTRACT: 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[degree sign]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.

Kakavandi B; Jonidi A Jafari; Rezaei R Kalantary; Nasseri S; Ameri A; Esrafily A

2013-02-01

202

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

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

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

2013-01-01

203

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

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

Cheng J; Zhou Y; Chen B; Wang J; Xia G; Jin N; Ding J; Gao C; Chen G; Miao Y; Li W; Liu Z; Wang X

2011-01-01

204

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

International Nuclear Information System (INIS)

Magnetite nanoparticles (Fe3O4 NPs) are manufactured nanomaterials increasingly used in healthcare for different medical applications ranging from diagnosis to therapy. This study deals with the irradiation of Fe3O4 NPs with a proton beam in order to produce 56Co as radiolabel and also with the possible use of nuclear techniques for the quantification of Fe3O4 NPs in biological systems. Particular attention has been focused on the size distribution (in the range of 100 nm) and the surface charge of the NPs characterizing them before and after the irradiation process in order to verify if these essential properties would be preserved during irradiation. Moreover, X-ray diffraction studies have been performed on radioactive and non-radioactive NPs, to assess if major changes in NPs structure might occur due to thermal and/or radiation effects. The radiation emitted from the radiolabels has been used to quantify the cellular uptake of the NPs in in vitro studies. As for the biological applications two cell lines have been selected: immortalized mouse fibroblast cell line (Balb/3T3) and human epithelial colorectal adenocarcinoma cell line (Caco-2). The cell uptake has been quantified by radioactivity measurements of the 56Co radioisotope performed with high resolution ?-ray spectrometry equipment. This study has showed that, under well-established irradiation conditions, 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.

2011-01-01

205

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

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

Natalie Frey Huls; Manh-Huong Phan; Arun Kumar; Subhra Mohapatra; Shyam Mohapatra; Pritish Mukherjee; Hariharan Srikanth

2013-01-01

206

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

Science.gov (United States)

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

Huls, Natalie Frey; Phan, Manh-Huong; Kumar, Arun; Mohapatra, Subhra; Mohapatra, Shyam; Mukherjee, Pritish; Srikanth, Hariharan

2013-01-01

207

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

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

Bao-an Chen; Pei-pei Mao; Jian Cheng; et al

2010-01-01

208

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

Science.gov (United States)

In this study, we report a novel method to synthesize core-shell structured Fe3O4 nanoparticles (NPs) covalently functionalized with iminodiacetic acid (IDA) via click chemistry between the azide and alkyne groups and charged with Cu2+. Firstly, the Fe3O4@SiO2 NPs were obtained using tetraethoxysilane (TEOS) to form a silica shell on the surface of the Fe3O4 core. The azide group-modified Fe3O4@SiO2 NPs were obtained by a sol-gel process using 3-azidopropyltriethoxysilane (AzPTES) as the silane agent. Fe3O4@SiO2-N3 was directly reacted with N-propargyl iminodiacetic via click chemistry, in the presence of a Cu(I) catalyst, to acquire the IDA-modified Fe3O4 NPs. Finally, through the addition of Cu2+, the Fe3O4@SiO2-IDA-Cu NP product was obtained. The morphology, structure and composition of the NPs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The resulting NPs showed a strong magnetic response to an externally applied magnetic field, a high adsorption capacity and excellent specificity towards hemoglobin (Hb). In addition, the Fe3O4@SiO2-IDA-Cu NPs can be used for the selective removal of abundant Hb protein in bovine and human blood samples.

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

2012-09-01

209

Magnetic Fe3O4@TiO2 nanoparticles-based test strip immunosensing device for rapid detection of phosphorylated butyrylcholinesterase.  

Science.gov (United States)

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 organophosphorous 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. Under the optimized conditions, the developed device shows a broader linear response over the concentration of OP-BChE from 0.05nM to 10nM within 15min, with a detection limit of 0.01nM. Coupling with a portable electrochemical detector, the integrated device with advanced nanotechnology displays great promise for sensitive, rapid and on-site evaluation of OP poisoning. PMID:23911770

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

2013-07-17

210

Magnetic Fe3O4@TiO2 nanoparticles-based test strip immunosensing device for rapid detection of phosphorylated butyrylcholinesterase.  

UK PubMed Central (United Kingdom)

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 organophosphorous 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. Under the optimized conditions, the developed device shows a broader linear response over the concentration of OP-BChE from 0.05 nM to 10 nM within 15 min, with a detection limit of 0.01 nM. Coupling with a portable electrochemical detector, the integrated device with advanced nanotechnology displays great promise for sensitive, rapid and on-site evaluation of OP poisoning.

Ge X; Zhang W; Lin Y; Du D

2013-12-01

211

Manufacture of IRDye800CW-coupled Fe3O4 nanoparticles and their applications in cell labeling and in vivo imaging  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In recent years, near-infrared fluorescence (NIRF)-labeled iron nanoparticles have been synthesized and applied in a number of applications, including the labeling of human cells for monitoring the engraftment process, imaging tumors, sensoring the in vivo molecular environment surrounding nanoparticles and tracing their in vivo biodistribution. These studies demonstrate that NIRF-labeled iron nanoparticles provide an efficient probe for cell labeling. Furthermore, the in vivo imaging studies show excellent performance of the NIR fluorophores. However, there is a limited selection of NIRF-labeled iron nanoparticles with an optimal wavelength for imaging around 800 nm, where tissue autofluorescence is minimal. Therefore, it is necessary to develop additional alternative NIRF-labeled iron nanoparticles for application in this area. Results This study manufactured 12-nm DMSA-coated Fe3O4 nanoparticles labeled with a near-infrared fluorophore, IRDye800CW (excitation/emission, 774/789 nm), to investigate their applicability in cell labeling and in vivo imaging. The mouse macrophage RAW264.7 was labeled with IRDye800CW-labeled Fe3O4 nanoparticles at concentrations of 20, 30, 40, 50, 60, 80 and 100 ?g/ml for 24 h. The results revealed that the cells were efficiently labeled by the nanoparticles, without any significant effect on cell viability. The nanoparticles were injected into the mouse via the tail vein, at dosages of 2 or 5 mg/kg body weight, and the mouse was discontinuously imaged for 24 h. The results demonstrated that the nanoparticles gradually accumulated in liver and kidney regions following injection, reaching maximum concentrations at 6 h post-injection, following which they were gradually removed from these regions. After tracing the nanoparticles throughout the body it was revealed that they mainly distributed in three organs, the liver, spleen and kidney. Real-time live-body imaging effectively reported the dynamic process of the biodistribution and clearance of the nanoparticles in vivo. Conclusion IRDye800CW-labeled Fe3O4 nanoparticles provide an effective probe for cell-labeling and in vivo imaging.

Hou Yong; Liu Yingxun; Chen Zhongping; Gu Ning; Wang Jinke

2010-01-01

212

Manufacture of IRDye800CW-coupled Fe3O4 nanoparticles and their applications in cell labeling and in vivo imaging.  

UK PubMed Central (United Kingdom)

BACKGROUND: In recent years, near-infrared fluorescence (NIRF)-labeled iron nanoparticles have been synthesized and applied in a number of applications, including the labeling of human cells for monitoring the engraftment process, imaging tumors, sensoring the in vivo molecular environment surrounding nanoparticles and tracing their in vivo biodistribution. These studies demonstrate that NIRF-labeled iron nanoparticles provide an efficient probe for cell labeling. Furthermore, the in vivo imaging studies show excellent performance of the NIR fluorophores. However, there is a limited selection of NIRF-labeled iron nanoparticles with an optimal wavelength for imaging around 800 nm, where tissue autofluorescence is minimal. Therefore, it is necessary to develop additional alternative NIRF-labeled iron nanoparticles for application in this area. RESULTS: This study manufactured 12-nm DMSA-coated Fe3O4 nanoparticles labeled with a near-infrared fluorophore, IRDye800CW (excitation/emission, 774/789 nm), to investigate their applicability in cell labeling and in vivo imaging. The mouse macrophage RAW264.7 was labeled with IRDye800CW-labeled Fe3O4 nanoparticles at concentrations of 20, 30, 40, 50, 60, 80 and 100 ?g/ml for 24 h. The results revealed that the cells were efficiently labeled by the nanoparticles, without any significant effect on cell viability. The nanoparticles were injected into the mouse via the tail vein, at dosages of 2 or 5 mg/kg body weight, and the mouse was discontinuously imaged for 24 h. The results demonstrated that the nanoparticles gradually accumulated in liver and kidney regions following injection, reaching maximum concentrations at 6 h post-injection, following which they were gradually removed from these regions. After tracing the nanoparticles throughout the body it was revealed that they mainly distributed in three organs, the liver, spleen and kidney. Real-time live-body imaging effectively reported the dynamic process of the biodistribution and clearance of the nanoparticles in vivo. CONCLUSION: IRDye800CW-labeled Fe3O4 nanoparticles provide an effective probe for cell-labeling and in vivo imaging.

Hou Y; Liu Y; Chen Z; Gu N; Wang J

2010-01-01

213

Catechol derivatives-coated Fe3O4 and gamma-Fe2O3 nanoparticles as potential MRI contrast agents.  

Science.gov (United States)

Superparamagnetic iron oxide nanoparticles, Fe(3)O(4) and gamma-Fe(2)O(3), were produced by the so-called polyol process. In order to stabilize the particles in a physiological environment as potential contrast agents for Magnetic Resonance Imaging (MRI), the as-prepared particles were successfully transferred to an aqueous medium through ligand exchange chemistry of the adsorbed polyol species with the dopamine or the catechaldehyde. The ligands were able to participate in bidentate binding to the nanoparticles surface and to improve the stability of aqueous suspensions of the nanoparticles. Analysis was performed by various techniques including X-ray diffraction, transmission electron microscopy, infrared spectroscopy and thermal analysis. The results of magnetic measurements and initial in vitro magnetic resonance imaging essays are presented for the pre- and post-surface modified nanoparticles, respectively and discussed in relation with their structure and microstructure. PMID:19853857

Basti, H; Ben Tahar, L; Smiri, L S; Herbst, F; Vaulay, M-J; Chau, F; Ammar, S; Benderbous, S

2009-09-25

214

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

Science.gov (United States)

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

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

2013-05-01

215

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

UK PubMed Central (United Kingdom)

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

Wang X; Liu H; Chen D; Meng X; Liu T; Fu C; Hao N; Zhang Y; Wu X; Ren J; Tang F

2013-06-01

216

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

Science.gov (United States)

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

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

2013-05-30

217

Nanorods of iron oxalate synthesized using reverse micelles: facile route for alpha-Fe2O3 and Fe3O4 nanoparticles.  

UK PubMed Central (United Kingdom)

Uniform and smooth nanorods of iron oxalate dihydrate have been synthesized using the reverse micellar route in the presence of the cationic surfactant CTAB (cetyltrimethyl ammonium bromide). These rods have an average diameter of 70 nm and length of 470 nm and show an antiferromagnetic ordering at 27 K. The oxalate rods act as suitable precursor for obtaining a variety of iron oxide nanoparticles depending on the nature of the atmosphere in which decomposition is performed. Spherical alpha-Fe2O3 nanoparticles (approximately 50 nm) were obtained when the nanorods were decomposed in air (500 degrees C) and show a transition from a weakly-ferromagnetic to weakly anti-ferromagnetic behaviour at approximately 225 K which is reminiscent of a Morin-like transition. Cuboidal Fe3O4 nanoparticles (approximately 60-70 nm) were obtained by the decomposition at 500 degrees C in vacuum (approximately 10(-5) torr) and show a Verwey transition at 122 K.

Ganguli AK; Ahmad T

2007-06-01

218

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

International Nuclear Information System (INIS)

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

2008-12-17

219

Sulfate-doped Fe3O4/Al2O3 nanoparticles as a novel adsorbent for fluoride removal from drinking water.  

UK PubMed Central (United Kingdom)

A novel adsorbent of sulfate-doped Fe3O4/Al2O3 nanoparticles with magnetic separability was developed for fluoride removal from drinking water. The nanosized adsorbent was characterized and its performance in fluoride removal was evaluated. Kinetic data reveal that the fluoride adsorption was rapid in the beginning followed by a slower adsorption process, nearly 90% adsorption can be achieved within 20 min and only 10-15% additional removal occurred in the following 8 h. The fluoride adsorption isotherm was well described by Elovich model. The calculated adsorption capacity of this nanoadsorbent for fluoride by two-site Langmuir model was 70.4 mg/g at pH 7.0. Moreover, this nanoadsorbent performed well over a considerable wide pH range of 4-10, and the fluoride removal efficiencies reached up to 90% and 70% throughout the pH range of 4-10 with initial fluoride concentrations of 10 mg/L and 50 mg/L, respectively. The observed sulfate-fluoride displacement and decreased sulfur content on the adsorbent surface reveal that anion exchange process was an important mechanism for fluoride adsorption by the sulfate-doped Fe3O4/Al2O3 nanoparticles. Moreover, a shift of the pH of zero point charge (pHPZC) of the nanoparticles and surface analysis based on X-ray photoelectron spectroscopy (XPS) suggest the formation of inner-sphere fluoride complex at the aluminum center as another adsorption mechanism. With the exception of PO4(3-), other co-existing anions (NO3(-), Cl(-) and SO4(2-)) did not evidently inhibit fluoride removal by the nanoparticles. Findings of this study demonstrate the potential utility of the nanoparticles as an effective adsorbent for fluoride removal from drinking water.

Chai L; Wang Y; Zhao N; Yang W; You X

2013-08-01

220

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

International Nuclear Information System (INIS)

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

2013-01-01

 
 
 
 
221

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

International Nuclear Information System (INIS)

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

2009-09-03

222

Magnetic solid-phase extraction based on tetrabenzyl modified Fe3O4 nanoparticles for the analysis of trace polycyclic aromatic hydrocarbons in environmental water samples.  

Science.gov (United States)

A novel sorbent for magnetic solid-phase extraction, 1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane (TBCD) modified magnetic nanoparticles, was synthesized in this work. The four benzyl groups of TBCD provide the Fe3O4-TBCD nanoparticles with strong adsorption capacity for polycyclic aromatic hydrocarbons (PAHs) due to their ?-? stacking interaction, which increases selectivity of the synthesized material to target analytes. The prepared material was characterized by scanning electron microscopy, X-ray diffraction patterns, Fourier transform infrared spectroscopy and vibrating sample magnetometry. The results indicated that the Fe3O4-TBCD nanoparticles were successfully prepared, and the particles were homogeneous nanospheres with excellent magnetic properties. Based on the optimized extraction conditions, a rapid and effective method was developed for the pre-concentration of PAHs from environmental water samples by combination with high performance liquid chromatography (HPLC). Satisfactory precision and accuracy of the developed method were obtained in a low concentration range of 0.3 ng L(-1) to 1.2 × 10(3) ng L(-1). This method produced lower limits of detection in the range of 3.0 × 10(-2) ng L(-1) to 1.2 ng L(-1). The high pre-concentration rate and efficiency of the method ensure its successful application in extraction of trace PAHs from large volumes of environmental water samples. The extraction recoveries in environmental water samples ranged from 81.1% to 115.5% with the relative standard deviations (n = 5) less than 10%. PMID:23928725

Zou, Ying; Chen, Yingzhuang; Yan, Zhihong; Chen, Chunyan; Wang, Jianping; Yao, Shouzhuo

2013-08-09

223

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

UK PubMed Central (United Kingdom)

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

Li J; Jiang H; Yu Z; Xia H; Zou G; Zhang Q; Yu Y

2013-02-01

224

Synthesis of Fe3O4@PbS hybrid nanoparticles through the combination of surface-initiated atom transfer radical polymerization and acidolysis by H2S.  

UK PubMed Central (United Kingdom)

A versatile approach to fabricate nanoparticles with multiple functionalities through the combined use of both surface-initiated ATRP and acidolysis by H2S techniques was demonstrated. The hybrid nanoparticles exhibited the core-shell structure having the magnetite nanoparticles as the core and the polymethacrylate as the shell with PbS nanoparticles distributing in the shell. The structure and morphology of the synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical and magnetic properties of the nanoparticles were investigated by UV-Vis spectroscopy, photoluminescence spectroscopy and vibrating sample magnetometer (VSM), respectively. It is observed that the absorption and emission behaviors of the Fe3O4@PbS hybrid nanoparticles were seriously influenced by the ATRP time and the reaction time with H2S. The saturated magnetization (Ms) decreased with the increase of ATRP time due to the formation of thicker shells coating on the surfaces of magnetite nanoparticles.

Zhou W; Chen Y; Wang X; Guo Z; Hu Y

2011-01-01

225

Silica supported Fe3O 4 magnetic nanoparticles for magnetic solid-phase extraction and magnetic in-tube solid-phase microextraction: application to organophosphorous compounds.  

UK PubMed Central (United Kingdom)

This work demonstrates the application of silica supported Fe3O4 nanoparticles as sorbent phase for magnetic solid-phase extraction (MSPE) and magnetic on-line in-tube solid-phase microextraction (Magnetic-IT-SPME) combined with capillary liquid chromatography-diode array detection (CapLC-DAD) to determine organophosphorous compounds (OPs) at trace level. In MSPE, magnetism is used as separation tool while in Magnetic-IT-SPME, the application of an external magnetic field gave rise to a significant improvement of the adsorption of OPs on the sorbent phase. Extraction efficiency, analysis time, reproducibility and sensitivity have been compared. This work showed that Magnetic-IT-SPME can be extended to OPs with successful results in terms of simplicity, speed, extraction efficiency and limit of detection. Finally, wastewater samples were analysed to determine OPs at nanograms per litre.

Moliner-Martinez Y; Vitta Y; Prima-Garcia H; González-Fuenzalida RA; Ribera A; Campíns-Falcó P; Coronado E

2013-10-01

226

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

Science.gov (United States)

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

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

2013-06-01

227

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

International Nuclear Information System (INIS)

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

2011-02-15

228

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

Directory of Open Access Journals (Sweden)

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

Cheng J; Cheng L; Chen B; Xia G; Gao C; Song H; Bao W; Guo Q; Zhang H; Wang X

2012-01-01

229

Sub-10 nm Fe3O4@Cu(2-x)S core-shell nanoparticles for dual-modal imaging and photothermal therapy.  

UK PubMed Central (United Kingdom)

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) Fe3O4@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 T2-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.

Tian Q; Hu J; Zhu Y; Zou R; Chen Z; Yang S; Li R; Su Q; Han Y; Liu X

2013-06-01

230

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

UK PubMed Central (United Kingdom)

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

Vallooran JJ; Negrini R; Mezzenga R

2013-01-01

231

Magnetic nanofibers with core (Fe3O4 nanoparticle suspension)/sheath (poly ethylene terephthalate) structure fabricated by coaxial electrospinning  

International Nuclear Information System (INIS)

One-dimensional magnetic nanostructures have recently attracted much attention because of their intriguing properties that are not realized by their bulk or particle form. These nanostructures are potentially useful for the application to ultrahigh-density data storages, sensors and bulletproof vest. The magnetic particles in magnetic nanofibers of blend types cannot fully align along the external magnetic field because magnetic particles are arrested in solid polymer matrix. To improve the mobility of magnetic particles, we used magneto-rheological fluid (MRF), which has the good mobility and dispersibility. Superparamagnetic core/sheath composite nanofibers were obtained with MRF and poly (ethylene terephthalate) (PET) solution via a coaxial electrospinning technique. Coaxial electrospinning is suited for fabricating core/sheath nanofibers encapsulating MRF materials within a polymer sheath. The magnetic nanoparticles in MRF were dispersed within core part of the nanofibers. The core/sheath magnetic composite nanofibers exhibited superparamagnetic behavior at room temperature and the magnetic nanoparticles in MRF well responded to an applied magnetic field. Also, the mechanical properties of the nanofiber were improved in the magnetic field. This study aimed to fabricate core/sheath magnetic composite nanofibers using coaxial electrospinning and characterize the magnetic as well as mechanical properties of composite nanofibers. - Highlights: ? The composite nanofibers including the MRF and PET. ? The fabrication of core/sheath structured nanofibers using coaxial electrospinning. ? Superparamagnetic composite nanofibers.

2012-01-01

232

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

Science.gov (United States)

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

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

2013-07-26

233

Sonochemical synthesis of magnetic core-shell Fe3O4-ZrO2 nanoparticles and their application to the highly effective immobilization of myoglobin for direct electrochemistry  

International Nuclear Information System (INIS)

Graphical abstract: Display Omitted Highlights: ? Magnetic core-shell Fe3O4-ZrO2 nanoparticle was synthesized by sonochemical approach. ? Fe3O4-ZrO2 NPs provided high capacity for trapping Mb on magnetic glassy carbon electrode surface. ? The constructed Mb/Fe3O4-ZrO2 film exhibited excellent electrocatalytic ability for the reduction of H2O2. ? The proposed method simplifies the immobilization methodology of proteins. - Abstract: In this study, bifunctional Fe3O4-ZrO2 magnetic core-shell nanoparticles (NPs), synthesized by a simple and effective sonochemical approach, were attached to the surface of a magnetic glassy carbon electrode (MGCE) and successfully applied to the immobilization/adsorption of myoglobin (Mb) for constructing a novel biosensor platform. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4-ZrO2 NPs, Mb could be easily immobilized on the surface of the electrode in the present of external magnetic field and well retained its bioactivity, hence dramatically facilitated direct electron transfer of Mb was demonstrated. The proposed Mb/Fe3O4-ZrO2 biofilm electrode exhibited excellent electrocatalytic behaviors towards the reduction of H2O2 with a linear range from 0.64 ?M to 148 ?M. This presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a simple, effective and inexpensive way to immobilize protein, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices.

2011-04-15

234

Effects of DMSA-coated Fe3O4 nanoparticles on the transcription of genes related to iron and osmosis homeostasis.  

UK PubMed Central (United Kingdom)

In this article, we checked the effect of 2,3-dimercaptosuccinic acid-coated Fe(3)O(4) nanoparticles on gene expression of mouse macrophage RAW264.7 cells and found that the transcription of several important genes related to intracellular iron homeostasis were significantly changed. We thus speculated that the cellular iron homeostasis might be disturbed by this nanoparticle through releasing iron ion in cells. To verify this speculation, we first confirmed the transcriptional changes of several key iron homeostasis- related genes, such as Tfrc, Trf, and Lcn2, using quantitative PCR, and found that an iron ion chelator, desferrioxamine, could alleviate the transcriptional alterations of two typical genes, Tfrc and Lcn2. Then, we designed and validated a method based on centrifugation for assaying intracellular irons in ion and nanoparticle state. After extensive measures of intracellular iron in two forms and total iron, we found that the intracellular iron ion significantly increased with intracellular total iron and nanoparticle iron, demonstrating degradation of this nanoparticle into iron ion in cells. We next mimicked the intralysosomal environment in vitro and verified that the internalized iron nanoparticle could release iron ion in lysosome. We found that as another important compensatory response to intracellular overload of iron ion, cells significantly downregulated the expressions of genes belonging to solute carrier family which are responsible for transferring many organic solutes into cells, such as Slc5a3 and Slc44a1, in order to prevent more organic solutes into cells and thus lower the intracellular osmosis. Based on these findings, we profiled a map of gene effects after cells were treated with this iron nanoparticle and concluded that the iron nanoparticles might be more detrimental to cell than iron ion due to its intracellular internalization fashion, nonspecific endocytosis.

Liu Y; Wang J

2013-02-01

235

Sensitive electrochemical analysis of BRAF V600E mutation based on an amplification-refractory mutation system coupled with multienzyme functionalized Fe3O4/Au nanoparticles.  

UK PubMed Central (United Kingdom)

A novel electrochemical biosensor was developed for the analysis of BRAF V600E mutation in colorectal cancer cell samples based on a dual amplification strategy of amplification-refractory mutation system (ARMS) PCR and multiple enzyme labels. The labeled amplicons were conjugated on Fe3O4/Au nanoparticles using Au-S linkages. Alkaline phosphatases were then loaded onto the nanoparticles through biotin-streptavidin interactions. The resultant composite nanoparticles were characterized by transmission electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. In the presence of 2-phospho-l-ascorbic acid, the mutant alleles were quantified on a screen-printed carbon electrode (SPCE) from the anodic current of the enzymatic product, ascorbic acid. BRAF V600E mutant alleles concentrations as low as 0.8% were successfully determined in an excess of wild-type background. In a cell-line dilution model, the proposed method was more sensitive than were DNA sequencing and agarose gel electrophoresis. This work demonstrates a new strategy for sensitivly detecting BRAF V600E variations. It can pave the way for analyzing other rare mutations in complex cancer samples because of its high sensitivity, simplicity, low cost, and easy validation of assay procedures.

Situ B; Cao N; Li B; Liu Q; Lin L; Dai Z; Zou X; Cai Z; Wang Q; Yan X; Zheng L

2013-05-01

236

Nanorods of iron oxalate synthesized using reverse micelles: facile route for alpha-Fe2O3 and Fe3O4 nanoparticles.  

Science.gov (United States)

Uniform and smooth nanorods of iron oxalate dihydrate have been synthesized using the reverse micellar route in the presence of the cationic surfactant CTAB (cetyltrimethyl ammonium bromide). These rods have an average diameter of 70 nm and length of 470 nm and show an antiferromagnetic ordering at 27 K. The oxalate rods act as suitable precursor for obtaining a variety of iron oxide nanoparticles depending on the nature of the atmosphere in which decomposition is performed. Spherical alpha-Fe2O3 nanoparticles (approximately 50 nm) were obtained when the nanorods were decomposed in air (500 degrees C) and show a transition from a weakly-ferromagnetic to weakly anti-ferromagnetic behaviour at approximately 225 K which is reminiscent of a Morin-like transition. Cuboidal Fe3O4 nanoparticles (approximately 60-70 nm) were obtained by the decomposition at 500 degrees C in vacuum (approximately 10(-5) torr) and show a Verwey transition at 122 K. PMID:17654986

Ganguli, Ashok K; Ahmad, Tokeer

2007-06-01

237

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

Science.gov (United States)

The magnetic nanoparticles coated with silica nanoparticles were synthesized to produce magnetic core–shell Fe3O4@SiO2 NPs, and then modified with rhodamine B derivatives. The Fe3O4@SiO2-Rho NPs exhibited selective "turn-on" type fluorescent enhancements and distinct color changes with Zn2+. No significant fluorescent changes were observed by addition of other metal ions (Ag+, Cu2+, Ni2+, Co2+, Cd2+, Mn2+, Pb2+, Hg2+, Fe3+, Cr3+) in the same suspension. The proposed Fe3O4@SiO2-Rho nanosensor can not only detect Zn2+ selectively but remove Zn2+ simultaneously.

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

2013-07-01

238

Photocatalytic characterization of silica coated titania nanoparticles with tunable coatings  

Energy Technology Data Exchange (ETDEWEB)

Photocatalytic experiments were conducted using the silica coated titania nanoparticles with tunable coatings to photocatalytically degrade methyl orange in water solutions. When the silica loading on titania nanoparticles was 4.67 wt%, the silica coating layer was incomplete and the photocatalytic activity of coated nanoparticles was higher than titania nanoparticles. However, when the silica loading on titania nanoparticles increased to 9.33 wt%, the thickness of silica coatings was 1.5 nm and the photocatalytic activity of coated nanoparticles sharply decreased. When the silica loading on titania nanoparticles increased to 25.19 wt%, the coated nanoparticles still exhibited a certain photacatalytic activity due to the porosity of silica coatings. The change of the effective tiania surface area available for methyl orange caused by silica coatings and the dispersion stability were used to explain the difference in photocatalytic activity.

Li, Q. Y., E-mail: qyli@home.ipe.ac.cn; Chen, Y. F.; Zeng, D. D.; Gao, W. M.; Wu, Z. J. [Chinese Academy of Sciences, Institute of Process Engineering (China)

2005-06-15

239

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

Science.gov (United States)

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

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

2013-03-01

240

Fe3O4/Au nanoparticles/lignin modified microspheres as effectual surface enhanced Raman scattering (SERS) substrates for highly selective and sensitive detection of 2,4,6-trinitrotoluene (TNT).  

UK PubMed Central (United Kingdom)

A new lignin modified hybrid microsphere, comprising poly(styrene-co-acrylic acid) core and magnetite (Fe3O4)/Au nanoparticle (NP) shell, was proposed here for the selective and highly sensitive detection and removal of 2,4,6-trinitrotoluene (TNT) explosives based on surface enhanced Raman scattering (SERS) and electrochemical detection methods. The presence of lignin and the highly packed layer of Fe3O4/AuNPs as a magnetic collector and metal enhancer for SERS signals allowed for the detection of TNT below 1 pM.

Mahmoud KA; Zourob M

2013-05-01

 
 
 
 
241

Fe3O4 magnetic nanoparticle peroxidase mimetic-based colorimetric assay for the rapid detection of organophosphorus pesticide and nerve agent.  

Science.gov (United States)

Rapid and sensitive detection methods are in urgent demand for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents for their neurotoxicity. In this study, we developed a novel Fe(3)O(4) magnetic nanoparticle (MNP) peroxidase mimetic-based colorimetric method for the rapid detection of organophosphorus pesticides and nerve agents. The detection assay is composed of MNPs, acetylcholinesterase (AChE), and choline oxidase (CHO). The enzymes AChE and CHO catalyze the formation of H(2)O(2) in the presence of acetylcholine, which then activates MNPs to catalyze the oxidation of colorimetric substrates to produce a color reaction. After incubation with the organophosphorus neurotoxins, the enzymatic activity of AChE was inhibited and produced less H(2)O(2), resulting in a decreased catalytic oxidation of colorimetric substrates over MNP peroxidase mimetics, accompanied by a drop in color intensity. Three organophosphorus compounds were tested on the assay: acephate and methyl-paraoxon as representative organophosphorus pesticides and the nerve agent Sarin. The novel assay displayed substantial color change after incubation in organophosphorus neurotoxins in a concentration-dependent manner. As low as 1 nM Sarin, 10 nM methyl-paraoxon, and 5 ?M acephate are easily detected by the novel assay. In conclusion, by employing the peroxidase-mimicking activity of MNPs, the developed colorimetric assay has the potential of becoming a screening tool for the rapid and sensitive assessment of the neurotoxicity of an overwhelming number of organophosphate compounds. PMID:23153113

Liang, Minmin; Fan, Kelong; Pan, Yong; Jiang, Hui; Wang, Fei; Yang, Dongling; Lu, Di; Feng, Jing; Zhao, Jianjun; Yang, Liu; Yan, Xiyun

2012-12-10

242

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

Science.gov (United States)

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 ?m, 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.

Kobori, H.; Takata, N.; Fukutome, N.; Yamasaki, A.; Sugimura, A.; Taniguchi, T.; Horie, T.; Naitoh, Y.; Shimizu, T.

2013-04-01

243

Fe3O4 magnetic nanoparticle peroxidase mimetic-based colorimetric assay for the rapid detection of organophosphorus pesticide and nerve agent.  

UK PubMed Central (United Kingdom)

Rapid and sensitive detection methods are in urgent demand for the screening of extensively used organophosphorus pesticides and highly toxic nerve agents for their neurotoxicity. In this study, we developed a novel Fe(3)O(4) magnetic nanoparticle (MNP) peroxidase mimetic-based colorimetric method for the rapid detection of organophosphorus pesticides and nerve agents. The detection assay is composed of MNPs, acetylcholinesterase (AChE), and choline oxidase (CHO). The enzymes AChE and CHO catalyze the formation of H(2)O(2) in the presence of acetylcholine, which then activates MNPs to catalyze the oxidation of colorimetric substrates to produce a color reaction. After incubation with the organophosphorus neurotoxins, the enzymatic activity of AChE was inhibited and produced less H(2)O(2), resulting in a decreased catalytic oxidation of colorimetric substrates over MNP peroxidase mimetics, accompanied by a drop in color intensity. Three organophosphorus compounds were tested on the assay: acephate and methyl-paraoxon as representative organophosphorus pesticides and the nerve agent Sarin. The novel assay displayed substantial color change after incubation in organophosphorus neurotoxins in a concentration-dependent manner. As low as 1 nM Sarin, 10 nM methyl-paraoxon, and 5 ?M acephate are easily detected by the novel assay. In conclusion, by employing the peroxidase-mimicking activity of MNPs, the developed colorimetric assay has the potential of becoming a screening tool for the rapid and sensitive assessment of the neurotoxicity of an overwhelming number of organophosphate compounds.

Liang M; Fan K; Pan Y; Jiang H; Wang F; Yang D; Lu D; Feng J; Zhao J; Yang L; Yan X

2013-01-01

244

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

Directory of Open Access Journals (Sweden)

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

Echevarria-Uraga JJ; García-Alonso I; Plazaola F; Insausti M; Etxebarria N; Saiz-López A; Fernández-Ruanova B

2012-01-01

245

Magnetic-Fe/Fe3O4-nanoparticle-bound SN38 as carboxylesterase-cleavable prodrug for the delivery to tumors within monocytes/macrophages  

Directory of Open Access Journals (Sweden)

Full Text Available The targeted delivery of therapeutics to the tumor site is highly desirable in cancer treatment, because it is capable of minimizing collateral damage. Herein, we report the synthesis of a nanoplatform, which is composed of a 15 ± 1 nm diameter core/shell Fe/Fe3O4 magnetic nanoparticles (MNPs) and the topoisomerase I blocker SN38 bound to the surface of the MNPs via a carboxylesterase cleavable linker. This nanoplatform demonstrated high heating ability (SAR = 522 ± 40 W/g) in an AC-magnetic field. For the purpose of targeted delivery, this nanoplatform was loaded into tumor-homing double-stable RAW264.7 cells (mouse monocyte/macrophage-like cells (Mo/Ma)), which have been engineered to express intracellular carboxylesterase (InCE) upon addition of doxycycline by a Tet-On Advanced system. The nanoplatform was taken up efficiently by these tumor-homing cells. They showed low toxicity even at high nanoplatform concentration. SN38 was released successfully by switching on the Tet-On Advanced system. We have demonstrated that this nanoplatform can be potentially used for thermochemotherapy. We will be able to achieve the following goals: (1) Specifically deliver the SN38 prodrug and magnetic nanoparticles to the cancer site as the payload of tumor-homing double-stable RAW264.7 cells; (2) Release of chemotherapeutic SN38 at the cancer site by means of the self-containing Tet-On Advanced system; (3) Provide localized magnetic hyperthermia to enhance the cancer treatment, both by killing cancer cells through magnetic heating and by activating the immune system.

Hongwang Wang; Tej B. Shrestha; Matthew T. Basel; Raj K. Dani; Gwi-Moon Seo; Sivasai Balivada; Marla M. Pyle; Heidy Prock; Olga B. Koper; Prem S. Thapa; David Moore; Ping Li; Viktor Chikan; Deryl L. Troyer; Stefan H. Bossmann

2012-01-01

246

Well aligned ZnO nanorods growth on the gold coated glass substrate by aqueous chemical growth method using seed layer of Fe3O4 and Co3O4 nanoparticles  

Science.gov (United States)

In this study, Fe3O4 and Co3O4 nanoparticles were prepared by co-precipitation method and sol-gel method respectively. The synthesised nanoparticles were characterised by X-ray diffraction [XRD] and Raman spectroscopy techniques. The obtained results have shown the nanocrystalline phase of obtained Fe3O4 and Co3O4 nanoparticles. Furthermore, the Fe3O4 and Co3O4 nanoparticles were used as seed layer for the fabrication of well-aligned ZnO nanorods on the gold coated glass substrate by aqueous chemical growth method. Scanning electron microscopy (SEM), high resolution transmission electron microscopy [HRTEM], as well as XRD and energy dispersive X-ray techniques were used for the structural characterisation of synthesised ZnO nanorods. This study has explored highly dense, uniform, well-aligned growth pattern along 0001 direction and good crystal quality of the prepared ZnO nanorods. ZnO nanorods are only composed of Zn and O atoms. Moreover, X-ray photoelectron spectroscopy was used for the chemical analysis of fabricated ZnO nanorods. In addition, the structural characterisation and the chemical composition study and the optical investigation were carried out for the fabricated ZnO nanorods and the photoluminescence [PL] spectrum have shown strong ultraviolet (UV) peak at 381 nm for Fe3O4 nanoparticles seeded ZnO nanorods and the PL spectrum for ZnO nanorods grown with the seed layer of Co3O4 nanoparticles has shown a UV peak at 382 nm. The green emission and orange/red peaks were also observed for ZnO nanorods grown with both the seed layers. This study has indicated the fabrication of well aligned ZnO nanorods using the one inorganic nanomaterial on other inorganic nanomaterial due to their similar chemistry.

Ibupoto, Z. H.; Khun, K.; Lu, Jun; Liu, Xianjie; AlSalhi, M. S.; Atif, M.; Ansari, Anees A.; Willander, M.

2013-04-01

247

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

Science.gov (United States)

The removal of hexavalent chromium [Cr (VI)], an important ground water pollutant by phyto-inspired Fe(0)/Fe(3)O(4) 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 Fe(0)/Fe(3)O(4) nanocomposites as well the yeast cell surface functional groups. PMID:23422514

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

2013-01-04

248

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

Science.gov (United States)

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

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

2013-03-01

249

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

UK PubMed Central (United Kingdom)

The removal of hexavalent chromium [Cr (VI)], an important ground water pollutant by phyto-inspired Fe(0)/Fe(3)O(4) 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 Fe(0)/Fe(3)O(4) nanocomposites as well the yeast cell surface functional groups.

Rao A; Bankar A; Kumar AR; Gosavi S; Zinjarde S

2013-03-01

250

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

International Nuclear Information System (INIS)

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

2011-01-01

251

Cellular biosensor based on red blood cells immobilized on Fe3O4 Core/Au Shell nanoparticles for hydrogen peroxide electroanalysis  

International Nuclear Information System (INIS)

[en] A core/shell Fe3O4/gold nanocomposite was prepared for immobilizing of red blood cells on a gold electrode via conjugation to a cysteamine monolayer. The hemoglobin in the film undergoes direct electron transfer at a formal potential of -330 mV and displays excellent electrocatalytic response to hydrogen peroxide, with a linear range from 9. 6 ?M to 2. 6 mM. The limit of detection is 4. 4 ?M (S/N = 3). The Michaelis-Menten constant is 120 ?M. Owing to its good biocompatibility, the biosensor exhibits good stability and acceptable reproducibility. The nanocomposite film provided a good matrix for the immobilization of cells and for the preparation of cellular biosensors. (author)

2010-01-01

252

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fe3O4 nanoparticle was synthesized in the solution involving water and ethanol. Then, ?-Fe2O3 shell was produced in situ on the surface of the Fe3O4 nanoparticle by surface oxidation in molten salts, forming ?-Fe2O3/Fe3O4 core-shell nanostructure. It was showed that the magnetic proper...

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

253

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

Science.gov (United States)

The CdTe quantum dots (QDs), graphene nanocomposite (CdTe-G) and dextran-Fe3O4 magnetic nanoparticles have been synthesized for developing an ultrasensitive electrochemiluminescence (ECL) immunoassay for Carcinoembryonic antigen 19-9 (CA 19-9) in serums. Firstly, the capture probes (CA 19-9 Ab1/Fe3O4) for enriching CA 19-9 were synthesized by immobilizing the CA 19-9's first antibody (CA 19-9 Ab1) on magnetic nanoparticles (dextran-Fe3O4). Secondly, the signal probes (CA 19-9 Ab2/CdTe-G), which can emit an ECL signal, were formed by attaching the secondary CA 19-9 antibody (CA 19-9 Ab2) to the surface of the CdTe-G. Thirdly, the above two probes were used for conjugating with a serial of CA 19-9 concentrations. Graphene can immobilize dozens of CdTe QDs on their surface, which can emit stronger ECL intensity than CdTe QDs. Based on the amplified signal, ultrasensitive antigen detection can be realized. Under the optimal conditions, the ECL signal depended linearly on the logarithm of CA 19-9 concentration from 0.005 to 100 pg/mL, and the detection limit was 0.002 pg/mL. Finally, five samples of human serum were tested, and the results were compared with a time-resolved fluorescence assay (TRFA). The novel immunoassay provides a stable, specific and highly sensitive immunoassay protocol for tumor marker detection at very low levels, which can be applied in early diagnosis of tumor. PMID:23685872

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

2013-05-17

254

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

Science.gov (United States)

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.

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

2013-01-01

255

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.  

UK PubMed Central (United Kingdom)

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.

Gan N; Zhou J; Xiong P; Li T; Jiang S; Cao Y; Jiang Q

2013-01-01

256

Magnetic Alignment of the Fe3O4-COATED Carbon Nanotubes Hybrids in Epoxy Nanocomposites  

Science.gov (United States)

Multi-walled carbon nanotubes (MWNTs), which were coated with magnetic Fe3O4 nanoparticles, were cured and aligned in epoxy resin under magnetic field. They were aligned end-to-up under 0.6 T magnetic field. When the Fe3O4-MWNTs hybrids content was 0.3%, the electric conductivity were 4.2 S/cm. Frequency and Fe3O4-MWNTs hybrids content are the key roles for electric conductivity.

Zheng, Ya-Ping; Chen, Wei; Wu, Fei; Zheng, Guo-Bin; Xu, Ya-Hong; Zhang, Tao

2013-08-01

257

Silica coated magnetic nanoparticles for separation of nuclear acidic waste  

International Nuclear Information System (INIS)

[en] Fe2O3 magnetic nanoparticles (MNPs) have been coated with silica, followed by covalent attachment of the actinide specific chelators to separate nuclear waste in acidic conditions. A general model is developed to relate the surface coating to the particle's magnetization change, providing an alternative way to characterize the size-distribution/aggregation of MNPs. The optimized silica coating protects the Fe2O3 MNPs from iron leaching under highly acidic conditions, facilitates the dispersion of MNPs, and dramatically increases the loading capacity of chelator onto the MNPs. Compared with the uncoated counterparts, the silica coated MNPs show enhanced actinide separation efficiency.

2010-01-01

258

Amperometric Hydrogen Peroxide Biosensor Based on Immobilization of Hemoglobin on a Glassy Carbon Electrode Modified with Fe3O4/Chitosan Core-Shell Microspheres  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Novel magnetic Fe3O4/chitosan (CS) microspheres were prepared using magnetic Fe3O4 nanoparticles and the natural macromolecule chitosan. Then, using an easy and effective hemoglobin (Hb) immobilization method, an innovative biosensor with a Fe3O4/CS-Hb-Fe3O4/CS “sandwich” configuration was construct...

Xue-Cai Tan; Jin-Lei Zhang; Sheng-Wei Tan; Dan-Dan Zhao; Zen-Wei Huang; Yan Mi; Zai-Yin Huang

259

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

Science.gov (United States)

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

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

2013-09-01

260

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

International Nuclear Information System (INIS)

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

2011-01-01

 
 
 
 
261

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

Science.gov (United States)

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 (?'', ?', ?'' and ?') 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).

Han, Xiao; Wang, Yuan-Sheng

2007-12-01

262

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

International Nuclear Information System (INIS)

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 (?-prime, ?', ?-prime and ?') 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).

2007-01-01

263

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

International Nuclear Information System (INIS)

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

2009-12-15

264

Self-Assembled Fe3O4 Nanoparticle Clusters as High-Performance Anodes for Lithium Ion Batteries via Geometric Confinement.  

UK PubMed Central (United Kingdom)

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

Lee SH; Yu SH; Lee JE; Jin A; Lee DJ; Lee N; Jo H; Shin K; Ahn TY; Kim YW; Choe H; Sung YE; Hyeon T

2013-09-01

265

Self-Assembled Fe3O4 Nanoparticle Clusters as High-Performance Anodes for Lithium Ion Batteries via Geometric Confinement.  

Science.gov (United States)

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

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

2013-08-09

266

Manufacture of IRDye800CW-coupled Fe3O4 nanoparticles and their applications in cell labeling and in vivo imaging  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background In recent years, near-infrared fluorescence (NIRF)-labeled iron nanoparticles have been synthesized and applied in a number of applications, including the labeling of human cells for monitoring the engraftment process, imaging tumors, sensoring the in vivo

Hou Yong; Liu Yingxun; Chen Zhongping; Gu Ning; Wang Jinke

267

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

UK PubMed Central (United Kingdom)

Polyol mediated synthesized luminescent YVO(4):Eu(3+) 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 YVO(4):Eu(3+) NPs in the SiO(2) matrix. N(2) adsorption/desorption analysis confirms the mesoporous nature of the MSNs and YVO(4):Eu(3+)-MSNs. No significant quenching of the YVO(4):Eu(3+) luminescence is observed for YVO(4):Eu(3+)-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 YVO(4):Eu(3+)-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 YVO(4):Eu(3+)-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 YVO(4):Eu(3+)-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 YVO(4):Eu(3+)-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 YVO(4):Eu(3+)-MSNs. In addition, an AC magnetic field triggers an enhanced drug release.

Shanta Singh N; Kulkarni H; Pradhan L; Bahadur D

2013-02-01

268

Fe3O4?????MWCNT/Fe3O4???????????????? Solvothermal Synthesis and Microwave Absorbing Properties of Fe3O4Microspheres and MWCNT/Fe3O4Heterostructures  

Directory of Open Access Journals (Sweden)

Full Text Available ??????????????????????????????????Fe3O4???????????????????(MWCNTs)??????????????????MWCNT/Fe3O4??????????????(SEM)?X-?????(XRD)?Fe3O4?????MWCNT/Fe3O4??????????????????Fe3O4??????????????????????????MWCNTs?????????MWCNTs?????????MWCNTs????Fe3O4??????????????????????????N5230A?????????????2?18 GHz????????????Fe3O4??????????????????????????????????????????????MWCNT/Fe3O4???????????????????????????? Fe3O4 microspheres were prepared via a facile solvothermal method using hydrous ferric chloride and anhydrous sodium acetate as materials, and ethylene glycol as solvent. Furthermore, the tunable denseness carbon nanotubes (MWCNTs)/Fe3O4 heterostructures were obtained by adjusting the ratio of ferric chloride and MWCNTs in the reaction system. The morphology and phase of the products were characterized by scanning electron microscope (SEM) and X-ray diffractometer (XRD). The results show that Fe3O4 microspheres with hierarchical structure wrap discontinuously on MWCNTs in the hybrids, and wrapping density increase with reduction of the amount of MWCNTs. The Fe3O4 microspheres with an unchanged phase in the heterostructures are composed of smaller particles after addition of MWCNTs than before. In addition, microwave absorbing properties of Fe3O4 microspheres and MWCNT/Fe3O4 heterostructures were measured at a microwave frequency range of 2 - 18 GHz with an N5230A vector network analyzer, and the results indicated that Fe3O4 microspheres obviously possessed the ability of microwave absorption and the strongest absorbing peak shifted to lower frequency with the coating thickness increase. Compared to Fe3O4 microspheres, MWCNT/Fe3O4 heterostructures tend to absorb microwave at higher frequency and weaken absorption at lower frequency.

???; ???; ???; ??

2011-01-01

269

Surface modification of Fe3O4@SiO2 microsphere by silane coupling agent  

Science.gov (United States)

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

Ahangaran, Fatemeh; Hassanzadeh, Ali; Nouri, Sirous

2013-04-01

270

Magnetic Fe3O4@mesoporous silica composites for drug delivery and bioadsorption.  

UK PubMed Central (United Kingdom)

Magnetic Fe(3)O(4)@mesoporous silica (MS) composites were synthesized by generating Fe(3)O(4) nanoparticles in the mesoporous silica matrix using the sol-gel method in nitrogen atmosphere. The mesoporous silica hosts include SBA-15 particles owning highly ordered p6mm mesostructure, siliceous mesostructured cellular foams (MCFs), and fiber-like mesoporous silica (FMS) with unique pore structures. The X-ray diffraction (XRD), transmission electron microscopy (TEM), and N(2) adsorption/desorption results show that Fe(3)O(4) functionalized MCFs and FMS possess suitable mesoporous structure for the adsorption of both small-molecular drug and large biomolecules. The biocompatibility tests on L929 fibroblast cells using MTT assay reveal low cytotoxicity of these systems. These Fe(3)O(4)@mesoporous silica composites show sustained release properties for aspirin in vitro. The release of the aspirin molecules from the pores of the Fe(3)O(4)@mesoporous silica composites is basically a diffusive process. Fe(3)O(4)@MCFs and Fe(3)O(4)@FMS owning larger pore size are good candidates for the adsorption of bovine serum albumin (BSA). These magnetic composites can be potential vectors for drug delivery and bioadsorption.

Huang S; Li C; Cheng Z; Fan Y; Yang P; Zhang C; Yang K; Lin J

2012-06-01

271

Magnetic Fe3O4@mesoporous silica composites for drug delivery and bioadsorption.  

Science.gov (United States)

Magnetic Fe(3)O(4)@mesoporous silica (MS) composites were synthesized by generating Fe(3)O(4) nanoparticles in the mesoporous silica matrix using the sol-gel method in nitrogen atmosphere. The mesoporous silica hosts include SBA-15 particles owning highly ordered p6mm mesostructure, siliceous mesostructured cellular foams (MCFs), and fiber-like mesoporous silica (FMS) with unique pore structures. The X-ray diffraction (XRD), transmission electron microscopy (TEM), and N(2) adsorption/desorption results show that Fe(3)O(4) functionalized MCFs and FMS possess suitable mesoporous structure for the adsorption of both small-molecular drug and large biomolecules. The biocompatibility tests on L929 fibroblast cells using MTT assay reveal low cytotoxicity of these systems. These Fe(3)O(4)@mesoporous silica composites show sustained release properties for aspirin in vitro. The release of the aspirin molecules from the pores of the Fe(3)O(4)@mesoporous silica composites is basically a diffusive process. Fe(3)O(4)@MCFs and Fe(3)O(4)@FMS owning larger pore size are good candidates for the adsorption of bovine serum albumin (BSA). These magnetic composites can be potential vectors for drug delivery and bioadsorption. PMID:22444483

Huang, Shanshan; Li, Chunxia; Cheng, Ziyong; Fan, Yong; Yang, Piaoping; Zhang, Cuimiao; Yang, Kuiyue; Lin, Jun

2012-02-28

272

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

International Nuclear Information System (INIS)

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

2012-01-01

273

Large scale growth and magnetic properties of Fe and Fe3O4 nanowires  

International Nuclear Information System (INIS)

[en] Fe and Fe3O4 nanowires have been synthesized by thermal decomposition of Fe(CO)5, followed by heat treatments. The Fe wires are formed through the aggregation of nanoparticles generated by decomposition of Fe(CO)5. A core-shell structure with an iron oxide shell and Fe core is observed for the as-prepared Fe wires. Annealing in air leads to the formation of Fe2O3/Fe3O4 wires, which after heat treatment in a N2/alcohol atmosphere form Fe3O4 wires with a sharp Verwey [Nature (London) 144, 327 (1939)] transition at 125 K. The Fe3O4 wires have coercivities of 261 and 735 Oe along the wire axis at RT and 5 K, respectively. The large increase of coercivity at 5 K as compared to RT is due to the increase of anisotropy resulting from the Verwey transition

2006-04-15

274

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, Fe3O4 nanoparticles (Fe3O4 NPs) grafted carboxyl groups of multiwalled carbon nanotubes with cationic polyelectrolyte poly (dimethyldiallylammonium chloride) (PDDA) (MWCNTs-COO?/PDDA@Fe3O4), are successfully synthesized and used for the extraction of six kinds of major toxic polychori...

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

275

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.  

UK PubMed Central (United Kingdom)

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

Tahmasebi E; Yamini Y

2012-12-01

276

Synthesis and characterization of Fe3O4 magnetic nanofluid  

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

277

Synthesis and characterization of Fe3O4 magnetic nanofluid  

Scientific Electronic Library Online (English)

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

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

2010-06-01

278

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

UK PubMed Central (United Kingdom)

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

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

2013-01-01

279

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

Science.gov (United States)

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

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

2013-01-01

280

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

International Nuclear Information System (INIS)

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.

2011-08-15

 
 
 
 
281

Preparation and Properties of Fe3O4 Biomimetic Micro-nano Structure Coatings  

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Nanoparticles filling is one of the most effective methods to build the micro-nano structure. In this paper, the composite coatings containing Fe3O4 nanoparticles were prepared from fluorinated silicon polymer by in-situ polymerization. FT-IR was used to characterize the structure of the composite m...

Xiao-zhou TIAN; Jian-fang WANG; Si-wen QIAN; Wen-jian WU; Xu GANG

282

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

International Nuclear Information System (INIS)

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

2011-01-01

283

Polymide/Fe3O4-carbonized Membranes for Gas Separation  

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

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

2010-01-01

284

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

UK PubMed Central (United Kingdom)

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

Wang L; Li J; Wang Z; Zhao L; Jiang Q

2013-02-01

285

Time-resolved polymer propagation for acrylic acid-mediated nanolatexes containing magnetic Fe3O4 cores.  

UK PubMed Central (United Kingdom)

This study reports on the time-resolved polymer propagation of thermal-sensitive latex nanoparticles containing Fe3O4 cores. The latex shells are made with poly(N-isopropylacrylamide-co-acrylic acid) (Fe3O4/P(NIPAAm-co-AAc)) at different reaction times. The Fe3O4 particles are first modified using AAc monomers. The AAc-modified Fe3O4 cores are then copolymerized with NIPAAm to form the latex shell. The Fe3O4 cores in the latex nanoparticles are confirmed using X-ray photoelectron spectroscopy (XPS), X-ray diffraction spectroscopy (XRD), and thermo gravimetric analyzer (TGA). As the reaction time is increased from 0.5 h to 2 h, the particle size enlarges from 100 to 250 nm and the Fe3O4 content decreases from 46.4% to 2.6%. The thermal responses are more pronounced in the 2 h sample with the phase transition temperature (lower critical solution temperature, LCST) about 35 degrees C. The nanoparticles show a gradient concentration distribution of AAc as the particles propagate. A higher AAc concentration is observed near'the Fe3O4 core and the AAc content deceases as the degree of polymerization increases in the latex particles. This declining AAc concentration is beneficial for profound thermal responses in the synthesized nanoparticle.

Chou FY; Shih CM; Lai JY; Chiu WY; Lue SJ

2013-03-01

286

Sonochemical synthesis, photocatalytic activity and optical properties of silica coated ZnO nanoparticles.  

UK PubMed Central (United Kingdom)

In this paper, we report the synthesis of silica coated ZnO nanoparticles by ultrasound irradiation of a mixture of dispersion of ZnO, tetraethoxysilane (TEOS), and ammonia in an ethanol-water solution medium. The silica coating layer formed at the initial TEOS/ZnO loading of 0.8 for 60 min ultrasonic irradiation was uniform and extended up to 3 nm from the ZnO surface as revealed from HR-TEM images. Silica coated ZnO nanoparticles demonstrated a significant inhibition of photocatalytic activity against photodegradation of methylene blue dye in aqueous solution. The effects of silica coating on the UV blocking property of ZnO nanoparticles were also studied.

Siddiquey IA; Furusawa T; Sato M; Bahadur NM; Alam MM; Suzuki N

2012-07-01

287

Preparation of Fe3O4Spherical Nanoporous Particles Facilitated by Polyethylene Glycol 4000  

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

Wang Li-Li; Jiang Ji-Sen

2009-01-01

288

Bioimaging application of highly luminescent silica-coated ZnO-nanoparticle quantum dots with biotin.  

UK PubMed Central (United Kingdom)

We synthesized ZnO-nanoparticle quantum dots (QDs) as a fluorescent probe for biological applications. Highly luminescent silica-coated ZnO-nanoparticle QDs dispersed in an aqueous medium were synthesized using the sol-gel process. The ZnO-nanoparticle QDs were coated with silica to improve the water stability of the ZnO nanoparticles. NH2 groups were introduced on the surface of the silica-coated ZnO-nanoparticle QDs first by the addition of 3-aminopropyltrimethoxysilane and then by biotinylation with sulfosuccinimidyl-6-(biotin-amido) hexanoate (sulfo-NHS-LC-bioton). We demonstrated that avidin-immobilized agarose beads were tagged by the silica-coated ZnO-nanoparticle QDs with biotin by the selective avidin-biotin interaction, furnishing a fluorescent image upon excitation with UV light. Furthermore, use of the silica-coated ZnO-nanoparticle QDs with biotin in cell-labeling applications was attempted, and attachment of the silica-coated ZnO-nanoparticle QDs with biotin to nerve cells and actin filaments was achieved.

Matsuyama K; Ihsan N; Irie K; Mishima K; Okuyama T; Muto H

2013-06-01

289

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

International Nuclear Information System (INIS)

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

2012-08-01

290

Facile synthesis of superparamagnetic Fe3O4@polyphosphazene@Au shells for magnetic resonance imaging and photothermal therapy.  

UK PubMed Central (United Kingdom)

Multifunctional nanoparticles were prepared by directly welding superparamagnetic Fe3O4 nanoparticles and Au shells together with highly cross-linked polyphosphazene as "glue" in a facile but effective way. The as-prepared particles can simultaneously take advantages of both magnetization of Fe3O4 core for magnetic resonance imaging diagnosis and strong near-infrared absorption of Au nanoshell for photothermal therapy.

Hu Y; Meng L; Niu L; Lu Q

2013-06-01

291

Synthesis of Fe3O4 magnetic fluid used for magnetic resonance imaging and hyperthermia  

International Nuclear Information System (INIS)

Fe3O4 magnetic nanoparticles were prepared by co-precipitation from FeSO4.7H2O and FeCl3.6H2O aqueous solutions using NaOH as precipitating reagent. The nanoparticles have an average size of 12 nm and exhibit superparamagnetism at room temperature. The nanoparticles were used to prepare a water-based magnetic fluid using oleic acid and Tween 80 as surfactants. The stability and magnetic properties of the magnetic fluid were characterized by Gouy magnetic balance. The experimental results imply that the hydrophilic block of Tween 80 can make the Fe3O4 nanoparticles suspending in water stable even after dilution and autoclaving. The magnetic fluid demonstrates excellent stability and fast magneto-temperature response, which can be used both in magnetic resonance imaging and magnetic fluid hyperthermia. - Highlights: ? Fe3O4 magnetic fluid (MF) was prepared by co-precipitation without protection gas and using NaOH as co-precipitation agent. ? Tween 80 was employed as the second layer surfactant. ? Hydrophilic ends of Tween 80 were exposed outside making the Fe3O4 MNPs suspending in water stably. ? Prepared MF can be used both in magnetic resonance imaging (MRI) and magnetic fluid hyperthermia (MFH).

1000-01-00

292

Facile one-step synthesis of Ag@Fe3O4 core–shell nanospheres for reproducible SERS substrates  

Science.gov (United States)

Ag@Fe3O4 core–shell nanospheres have been synthesized and were first used as an active SERS substrate.They showed high detection sensitivity for rhodamine 6G and 4-aminothiophenol.The SERS activity of Ag@Fe3O4 nanospheres was much higher than that of pure Ag nanoparticles.Ag@Fe3O4 nanospheres could be easily recycled with steady high SERS activity.Such SERS substrate is potentially applicable for chemical and biomolecular assay.

Sun, Lijuan; He, Jiang; An, Songsong; Zhang, Junwei; Ren, Dong

2013-08-01

293

Preparation and characterization of Fe3O4 magnetic composite microspheres covered by a P(MAH-co-MAA) copolymer  

International Nuclear Information System (INIS)

[en] A magnetic core-shell-layered polymer microsphere (MPS) was successfully synthesized by a dispersion polymerization route, where the modified Fe3O4 nanoparticles (MFN) were used as a core, while poly(maleic anhydride-co-methacrylic acid) P(MAH-co-MAA) as a shell was covered on the surface of the Fe3O4 nanoparticles. Environmental scanning electron microscope (ESME) and transmission electron microscope (TEM) measurements indicate that the magnetic P(MAH-co-MAA)/Fe3O4 composite microspheres assume sphericity and have a novel core-shell-layered structure. The crystal particle sizes of the unimproved Fe3O4 and the MFN samples vary from 8 to 16 nm in diameter, and the average size is about 10.6 nm in diameter. The core-shell magnetic composite microspheres can be adjusted by changing the stirring speed. Since multiple Fe3O4 cores were coated with a proper percentage of P(MAH-co-MAA) copolymers, and therefore lower density was acquired for the MPS, which improved sedimentation and dispersion behavior. The saturated magnetization of pure Fe3O4 nanoparticles reaches 48.1 emu g-1 and the value for composite nanoparticles was as high as 173.5 emu g-1. The nanoparticles show strong superparamagnetic characteristics and can be expected to be used as a candidate for magnetism-controlled drug release.

2009-01-01

294

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

International Nuclear Information System (INIS)

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

2007-01-01

295

Silica coating of CeO2 nanoparticles by a fast microwave irradiation method  

International Nuclear Information System (INIS)

A rapid and simple route for silica coating with base catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS) precursor in water-ethanol solvent using microwave irradiation to encapsulate CeO2 nanoparticles with a silica shell is studied. From X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectra analysis, it was confirmed that silica in the coating is attached on the CeO2 nanoparticles surface through Ce-O-Si chemical bonds. The coating extent was increased with increasing in TEOS loading and surface characteristics of coated CeO2 nanoparticles with high silica extents showed similar electrokinetic behavior to SiO2 particles. The high resolution transmission electron microscope (HR-TEM) images also showed that SiO2 coated the cubic shaped CeO2 nanoparticles as thin uniform layers (5 nm). The catalytic activities of non-coated and silica coated CeO2 nanoparticles for oxidation of organic compound were evaluated by degradation of methylene blue in air atmosphere at 403 K. Furthermore, the optical properties of non-coated and silica coated CeO2 nanoparticles were evaluated by UV-vis spectroscopic analyses. These analytical results indicated that silica coated CeO2 nanoparticles with thin silica layer could be prepared using sol-gel method assisted by microwave irradiation within 2 min and this material showed better performances than original CeO2 nanoparticles.

2008-12-30

296

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

Science.gov (United States)

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

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

2013-03-01

297

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

Directory of Open Access Journals (Sweden)

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

Xiao Qi; Xiao Chong

2009-01-01

298

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

International Nuclear Information System (INIS)

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

2013-01-01

299

Preparation and Properties of Fe3O4 Biomimetic Micro-nano Structure Coatings  

Directory of Open Access Journals (Sweden)

Full Text Available Nanoparticles filling is one of the most effective methods to build the micro-nano structure. In this paper, the composite coatings containing Fe3O4 nanoparticles were prepared from fluorinated silicon polymer by in-situ polymerization. FT-IR was used to characterize the structure of the composite material. SEM and AFM were performed to observe the microstructure of the coatings. The contact angle of water and coatings was tested. The results showed that the biomimetic micro-nano structure of the coatings, which formed on the glass plate, was exactly familiar with that of the surface of lotus leaves. Keyword: micro-nano structure; Fe3O4 nanoparticles; in-situ polymerization; biomimetic

Xiao-zhou TIAN; Jian-fang WANG; Si-wen QIAN; Wen-jian WU; Xu GANG

2010-01-01

300

Antifungal activity of multifunctional Fe3O4-Ag nanocolloids  

International Nuclear Information System (INIS)

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

1470-01-00

 
 
 
 
301

High efficiency protein separation with organosilane assembled silica coated magnetic nanoparticles  

Science.gov (United States)

This work describes the development of high efficiency protein separation with functionalized organosilanes on the surface of silica coated magnetic nanoparticles. The magnetic nanoparticles were synthesized with average particle size of 9 nm and silica coated magnetic nanoparticles were obtained by controlling the coating thicknesses on magnetic nanoparticles. The silica coating thickness could be uniformly sized with a diameter of 10 40 nm by a sol gel approach. The surface modification was performed with four kinds of functionalized organosilanes such as carboxyl, aldehyde, amine, and thiol groups. The protein separation work with organosilane assembled silica coated magnetic nanoparticles was achieved for model proteins such as bovine serum albumin (BSA) and lysozyme (LSZ) at different pH conditions. Among the various functionalities, the thiol group showed good separation efficiency due to the change of electrostatic interactions and protein conformational structure. The adsorption efficiency of BSA and LSZ was up to 74% and 90% corresponding pH 4.65 and pH 11.

Chang, Jeong Ho; Kang, Ki Ho; Choi, Jinsub; Jeong, Young Keun

2008-10-01

302

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

Directory of Open Access Journals (Sweden)

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

Salehizadeh Hossein; Hekmatian Elham; Sadeghi Meisam; Kennedy Kevin

2012-01-01

303

Facile synthesis of pectin coated Fe3O4 nanospheres by the sonochemical method  

Science.gov (United States)

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

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

2013-04-01

304

Synthesis and magnetic properties of core/shell FeO/Fe3O4 nano-octopods  

Science.gov (United States)

We report the synthesis and magnetic properties of core/shell FeO/Fe3O4 nanoparticles with an average size of 30 nm in a complex quasi-octopod shape. FeO nanoparticles were synthesized by a wet chemical synthesis route followed by partial oxidation to form core/shell structured FeO/Fe3O4 octopods. X-ray diffraction and transmission electron microscopy confirmed the presence of iron oxide phases and the formed core/shell FeO/Fe3O4 morphology. Magnetic measurements revealed two distinct temperatures corresponding to the thermally activated Verwey transition (TV ~ 120 K) of the ferrimagnetic Fe3O4 shell and the Neel temperature (TN ~ 230 K) of the antiferromagnetic FeO core. The nanoparticles exhibited a strong horizontal shift in the field-cooled hysteresis loop (the so-called exchange bias (EB) effect) accompanied by enhanced coercivity. The Meiklejohn-Bean model has been implemented to quantify the amount of frozen spins that locate at the interface between FeO and Fe3O4 and are responsible for the observed EB effect.

Khurshid, Hafsa; Chandra, Sayan; Li, Wanfeng; Phan, M. H.; Hadjipanayis, G. C.; Mukherjee, P.; Srikanth, H.

2013-05-01

305

Experimental study of natural convection enhancement using a Fe3O4-water based magnetic nanofluid.  

UK PubMed Central (United Kingdom)

The effect of nanoparticles dispersed in a carrier fluid on the natural convection heat transfer is still raising controversies. While the reported experimental results show no improvement or even worsening of the heat transfer performance of nanofluids, the numerical simulations show an increase of the heat transfer coefficient, at least for certain ranges of Ra number. We report an experimental investigation regarding the natural convection heat transfer performance of a Fe3O4-water based nanofluid, in a cylindrical enclosure. The fluid was heated linearly from the bottom wall using an electric heater and cooled from the upper wall by a constant flow of water, such that a constant temperature difference between the upper and bottom walls was obtained at steady-state. The experiment was also carried out using water, in order to observe the effect of the addition of Fe3O4 nanoparticles on the heat transfer coefficient. Several regimes were tested, both for water and nanofluid. The experimental results showed that values obtained for the heat transfer coefficient for Fe3O4-water nanofluid were higher than those for water, at the same temperature difference. The present experimental results are also compared with our previous work and the reference literature.

Stoian FD; Holotescu S

2012-10-01

306

Experimental study of natural convection enhancement using a Fe3O4-water based magnetic nanofluid.  

Science.gov (United States)

The effect of nanoparticles dispersed in a carrier fluid on the natural convection heat transfer is still raising controversies. While the reported experimental results show no improvement or even worsening of the heat transfer performance of nanofluids, the numerical simulations show an increase of the heat transfer coefficient, at least for certain ranges of Ra number. We report an experimental investigation regarding the natural convection heat transfer performance of a Fe3O4-water based nanofluid, in a cylindrical enclosure. The fluid was heated linearly from the bottom wall using an electric heater and cooled from the upper wall by a constant flow of water, such that a constant temperature difference between the upper and bottom walls was obtained at steady-state. The experiment was also carried out using water, in order to observe the effect of the addition of Fe3O4 nanoparticles on the heat transfer coefficient. Several regimes were tested, both for water and nanofluid. The experimental results showed that values obtained for the heat transfer coefficient for Fe3O4-water nanofluid were higher than those for water, at the same temperature difference. The present experimental results are also compared with our previous work and the reference literature. PMID:23421199

Stoian, Floriana D; Holotescu, Sorin

2012-10-01

307

Luminescence enhancement from silica-coated gold nanoparticle agglomerates following multi-photon excitation.  

UK PubMed Central (United Kingdom)

Multi-photon absorption induced luminescence (MAIL) from bare gold nanoparticles, silica-coated particles, as well as silica-coated agglomerated gold nanoparticles suspended in aqueous solution was studied by using time-resolved and steady-state luminescence spectroscopy. The nanoparticles were excited by femtosecond pulses of wavelengths ranging from 630 nm to 900 nm. The luminescence from the particles exhibits a broad spectrum in the UV and VIS region. The time-resolved measurements indicate a luminescence lifetime of a few ps, limited by the response of the experimental system. The studied dependence of the MAIL efficiency on the excitation wavelength showed that the luminescence from silica-coated agglomerates was enhanced over the whole range of excitation wavelengths, when compared to the luminescence from individual gold nanoparticles. The agglomerates show an almost excitation wavelength independent efficiency of the MAIL, while for individual nanoparticles a rapid decrease of the MAIL efficiency was observed with increasing excitation wavelength. The observed enhancement of the MAIL from the agglomerated nanostructures can be attributed to the presence of localized surface plasmon resonances in the spectral region corresponding to the excitation wavelengths. The high MAIL efficiency from the agglomerated nanoparticle structures in the near-infrared could be an advantage in the expanding field of luminescence-based-imaging, as well as in biosensor technology.

Viarbitskaya S; Ryderfors L; Mikaelsson T; Mukhtar E; Johansson LB

2011-01-01

308

Synthesis and characterization of Fe3O4 and ZnO nanocomposites by the sol-gelmethod  

Science.gov (United States)

In this work, magnetite (Fe3O4) nanoparticles were first prepared from ferric nitrate (Fe(NO3)3 9H2O) and ethylene glycol (C2H6O2) in inert atmosphere using the sol-gel method. In the next stage, composite nanopowders of Fe3O4-ZnO were obtained from zinc acetate and diethanolamine via the sol-gel method. The precursor was first dried and then annealed in vacuum furnace at different temperatures. The X-ray diffraction results confirm the formation of Fe3O4-ZnO nanocomposites. Transmission Electron Microscopy showed that the prepared powders are made of the spherical shape particles with an average size of about 40 nm. Fourier transform infrared spectra for the characteristic absorption of Zn-O bond is at 453.1 cm-1and of Fe-O bond is 540.2 cm-1. Results of vibrating sample magnetometer reveal that the Fe3O4 nanoparticles are superparamagnetic, whereas in the form of Fe3O4-ZnO nanocomposites arenot.

Hasanpour, A.; Niyaifar, M.; Asan, M.; Amighian, J.

2013-05-01

309

Multifunctional PNIPAM/Fe3O4-ZnS hybrid hollow spheres: synthesis, characterization, and properties.  

UK PubMed Central (United Kingdom)

Multifunctional PNIPAM/Fe3O4-ZnS hybrid hollow spheres integrating magnetism, luminescence, and temperature responses into one single entity have been successfully fabricated via a facile method. First, the cross-linked Poly (N-isopropylacrylamide) (PNIPAM) hollow spheres were synthesized via a classical method, named one-pot "self-removing" process. Then, Fe3O4 and ZnS nanoparticles were in situ precipitated on the surface of the PNIPAM hollow spheres. The PNIPAM/Fe3O4-ZnS hybrid hollow spheres exhibit magnetic property, which indicates the potential application in drug targeting. In addition, ZnS nanoparticles in the shell play an important role as a luminescent label for tracking the drug delivery. Meanwhile, the existence of PNIPAM provides a thermosensitive property. All these results indicate that the obtained composite can be expected to be used as a smart drug delivery material.

Liu G; Hu D; Chen M; Wang C; Wu L

2013-05-01

310

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

UK PubMed Central (United Kingdom)

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

Zhang B; Zhang H; Li X; Lei X; Li C; Yin D; Fan X; Zhang Q

2013-10-01

311

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

Science.gov (United States)

BSA/Fe3O4 magnetic composite microspheres with high saturation magnetization and paramagnetic property were prepared via inverse emulsion technology at room temperature, bovine serum albumin (BSA, 60 KD), magnetic nanoparticles (Fe3O4) and glutaraldehyde as macromonomer, inorganic particles and cross-linking agent, respectively. Fourier transform infrared (FTIR), scanning electron microscope (SEM), metalloscope, and particle size analyzer were used to characterize morphology and structure of composite microspheres. Vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA) were used to test magnetic properties of the synthesized samples, adsorption capacity of microspheres was determined by ultraviolet spectrophotometer (UV). The results showed that BSA/Fe3O4 microspheres were 43 ?m with relatively narrow particle size distribution, perfect sphere-shaped morphologies, superparamagnetism with a saturation magnetization of 11 emu/g, and high magnetic content with a value of 57.29%. The main factors influencing properties of microspheres including raw material ratio, the amount of emulsifier and cross-linking agent, agitation speed were investigated and optimized. Furthermore, these microspheres accompanying with high separable and reusable efficient may have great potential application in the field of separation, in particular, removal of antibiotics. Adsorption capacities of the 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. PMID:23910359

Zhang, Baoliang; Zhang, Hepeng; Li, Xiangjie; Lei, Xingfeng; Li, Chunmei; Yin, Dezhong; Fan, Xinlong; Zhang, Qiuyu

2013-07-01

312

Multipositional silica-coated silver nanoparticles for high-performance polymer solar cells.  

UK PubMed Central (United Kingdom)

We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles.

Choi H; Lee JP; Ko SJ; Jung JW; Park H; Yoo S; Park O; Jeong JR; Park S; Kim JY

2013-05-01

313

Synthesis and characterization of rice straw/Fe3O4 nanocomposites by a quick precipitation method.  

Science.gov (United States)

Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs) with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O), ferrous chloride (FeCl2·4H2O), sodium hydroxide (NaOH) and urea (CH4N2O) were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs) were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray fluorescence (EDXF) and Fourier transforms infrared spectroscopy (FT?IR). The rice straw/Fe3O4-NCs prepared by this method have magnetic properties. PMID:23739066

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

2013-06-05

314

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

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

315

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

Science.gov (United States)

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

Zhou, Li; Deng, Huiping; Wan, Junli; Shi, Jun; Su, Tong

2013-10-01

316

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

CERN Multimedia

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

Dash, Monika

2013-01-01

317

Facile hydrogen-bond-assisted polymerization and immobilization method to synthesize hierarchical Fe3O4@poly(4-vinylpyridine-co-divinylbenzene)@Au nanostructures and their catalytic applications.  

UK PubMed Central (United Kingdom)

Hierarchical Fe3O4@poly(4-vinylpyridine-co-divinylbenzene)@Au (Fe3O4@P(4-VP-DVB)@Au) nanostructures were fabricated successfully by means of a facile two-step synthesis process. In this study, well-defined core-shell Fe3O4@P(4-VP-DVB) microspheres were first prepared with a simple polymerization method, in which 4-VP was easily polymerized on the surface of Fe3O4 nanoparticles by means of strong hydrogen-bond interactions between -COOH groups on poly(acrylic acid)-modified Fe3O4 nanoparticles and a 4-VP monomer. HAuCl4 was adsorbed on the chains of a P(4-VP) shell and then reduced to Au nanoparticles by NaBH4, which were embedded into the P(4-VP) shell of the composite microspheres to finally form the Fe3O4@P(4-VP-DVB)@Au nanostructures. The obtained Fe3O4@P(4-VP-DVB)@Au catalysts with different Au loadings were applied in the reduction of 4-nitrophenol (4-NP) and exhibited excellent catalytic activity (up to 3025?h(-1) of turnover frequency), facile magnetic separation (up to 31.9?emu?g(-1) of specific saturation magnetization), and good durability (over 98?% of conversion of 4-NP after ten runs of recyclable catalysis and almost negligible leaching of Au).

Guo W; Wang Q; Wang G; Yang M; Dong W; Yu J

2013-06-01

318

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

Directory of Open Access Journals (Sweden)

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

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

2012-01-01

319

Fast and facile synthesis of silica coated silver nanoparticles by microwave irradiation.  

UK PubMed Central (United Kingdom)

A novel, fast and facile microwave technique has been developed for preparing monodispersed silica coated silver (Ag@SiO(2)) nanoparticles. Without using any other surface coupling agents such as 3-aminopropyltrimethoxysilane (APS) or polymer such as polyvinyl pyrrolidone (PVP), Ag@SiO(2) nanoparticles could be easily prepared by microwave irradiation of a mixture of colloidal silver nanoparticles, tetraethoxysilane (TEOS) and catalyst for only 2 min. The thickness of silica shell could be conveniently controlled in the range of few nanometers (nm) to 80 nm by changing the concentration of TEOS. Transmission electron microscopy (TEM) and UV-visible spectroscopy were employed to characterize the morphology and optical properties of the prepared Ag@SiO(2) nanoparticles, respectively. The prepared Ag@SiO(2) nanoparticles exhibited a change in surface plasmon absorption depending on the silica thickness. Compared to the conventional techniques based on Stöber method, which need 4-24 h for silica coating of Ag nanoparticles, this new technique is capable of synthesizing monodispersed, uniform and single core containing Ag@SiO(2) nanoparticles within very short reaction time. In addition, straightforward surface functionalization of the prepared Ag@SiO(2) nanoparticles with desired functional groups was performed to make the particles useful for many applications. The components of surface functionalized nanoparticles were examined by Fourier transform infrared (FT-IR) spectroscopy, zeta potential measurements and X-ray photoelectron spectroscopy (XPS).

Bahadur NM; Furusawa T; Sato M; Kurayama F; Siddiquey IA; Suzuki N

2011-03-01

320

Synthesis of optically active silica-coated NdF3 core-shell nanoparticles.  

UK PubMed Central (United Kingdom)

Silica surface-modified NdF(3) core-shell nanoparticles were prepared by sol-gel route. The prepared core-shell nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis absorption and photoluminescence (PL) spectroscopy studies. Phase identification of the NdF(3) and silica-coated NdF(3) core-shell nanoparticles which was carried-out by XRD, confirms the formation of a well-crystallized hexagonal phase structure. Due to the silica-surface modification, the nanoparticles were not found to be well-separated (agglomerated) in ethanol solvent as scanned by TEM. The results of the FTIR studies conducted on these core-shell reveal the binding of silica with the NdF(3) nanoparticles. The largest intensity and shape variation were observed in all transitions as compared to non-silica modified NdF(3) nanoparticle spectra, and were attributed to the environment around the Nd(III) ion due to coordination of silica molecule(s). A significant enhancement in the emission intensity was measured in silica surface modified NdF(3) core-shell nanoparticles due to the successful silica coating on the surface of nanoparticles. The results of these studies suggest that these nanoparticles may find potential applications in the areas of bioimaging, protein-labeling, optical biosensors and drug delivery, etc.

Ansari AA; Singh SP; Singh N; Malhotra BD

2012-02-01

 
 
 
 
321

Synthesis of optically active silica-coated NdF 3 core-shell nanoparticles  

Science.gov (United States)

Silica surface-modified NdF 3 core-shell nanoparticles were prepared by sol-gel route. The prepared core-shell nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis absorption and photoluminescence (PL) spectroscopy studies. Phase identification of the NdF 3 and silica-coated NdF 3 core-shell nanoparticles which was carried-out by XRD, confirms the formation of a well-crystallized hexagonal phase structure. Due to the silica-surface modification, the nanoparticles were not found to be well-separated (agglomerated) in ethanol solvent as scanned by TEM. The results of the FTIR studies conducted on these core-shell reveal the binding of silica with the NdF 3 nanoparticles. The largest intensity and shape variation were observed in all transitions as compared to non-silica modified NdF 3 nanoparticle spectra, and were attributed to the environment around the Nd(III) ion due to coordination of silica molecule(s). A significant enhancement in the emission intensity was measured in silica surface modified NdF 3 core-shell nanoparticles due to the successful silica coating on the surface of nanoparticles. The results of these studies suggest that these nanoparticles may find potential applications in the areas of bioimaging, protein-labeling, optical biosensors and drug delivery, etc.

Ansari, Anees A.; Singh, S. P.; Singh, N.; Malhotra, B. D.

2012-02-01

322

Improved electrochemical performance of porous Fe3O4/carbon core/shell nanorods as an anode for lithium-ion batteries  

International Nuclear Information System (INIS)

Highlights: ? We prepared porous Fe3O4/C core/shell nanorods by a facile hydrothermal method using porous Fe2O3 nanorods as the precursor. ? The Fe3O4/C nanorods are homogenously coate