Structural and magnetic properties of iron nanowires and iron nanoparticles fabricated through a reduction reaction

• Marcin Krajewski,
• Wei Syuan Lin,
• Hong Ming Lin,
• Katarzyna Brzozka,
• Sabina Lewinska,
• Natalia Nedelko,
• Anna Slawska-Waniewska,
• Jolanta Borysiuk and
• Dariusz Wasik

Beilstein J. Nanotechnol. 2015, 6, 1652–1660, doi:10.3762/bjnano.6.167

• well-known that iron nanomaterials in the presence of even small quantities of oxygen tend to be oxidized immediately. The increasing temperature leads to progressive oxidation of iron to Fe3O4 (large nanostructures) or γ-Fe2O3 (small nanostructures) and following transformation to α-Fe2O3 [12][15

Thermal treatment of magnetite nanoparticles

• Beata Kalska-Szostko,
• Urszula Wykowska,
• Dariusz Satula and
• Per Nordblad

Beilstein J. Nanotechnol. 2015, 6, 1385–1396, doi:10.3762/bjnano.6.143

• nanoparticles oxidize to a mixture of iron oxides (γ-Fe2O3 and α-Fe2O3) even at 200 °C [19]. However, this temperature can vary due to the high surface area and various activity of the nanoparticles, which results in a more exothermic heat process during oxidation at low temperature. In general, it can be

• assumed that phase transformation in nano-granular systems occurs from 200 to 600 °C with different contribution from both oxides, γ-Fe2O3 and α-Fe2O3 [20]. It should also be underlined that the data regarding the behavior of nanosystems at elevated temperatures are very different and generalizations

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• that in the hybrid nanocomposite material the thick silica coating acts as diamagnetic component. Similarly, Yi et al. [45] reported the synthesis of silica-coated γ-Fe2O3 magnetic NPs and CdSe QDs through a reverse microemulsion approach. The synthesis involved the isolated preparation of magnetic NPs

• maghemite (γ-Fe2O3) NPs were prepared by using 1,2-hydroxydodecanoic acid and then these were coupled with CdSe/ZnS QDs. Finally, silica coating was achieved by using TEOS. The TEM and SEM images confirmed the incorporation of NPs inside silica. The presence of QDs was confirmed by spectrophotometric

• used as MR contrast agent in solution and in cells. Further, Chekina et al. [57] reported the synthesis of bifunctional NPs through a silinazation process. The maghemite (γ-Fe2O3) NPs were prepared by oxidizing pure magnetite NPs with sodium hypochlorite. The magnetic NPs were then coated with silica

Biopolymer colloids for controlling and templating inorganic synthesis

• Laura C. Preiss,
• Katharina Landfester and
• Rafael Muñoz-Espí

Beilstein J. Nanotechnol. 2014, 5, 2129–2138, doi:10.3762/bjnano.5.222

• . [5] prepared chitosan/silica composite microspheres by mixing an aqueous solution of the biopolymer with commercial nanosized silica particles. The obtained microparticles were dried afterwards. In further examples, chitosan matrices have also been used to immobilize CdSe quantum dots [6] and γ-Fe2O3

Cathode lens spectromicroscopy: methodology and applications

• T. O. Menteş,
• G. Zamborlini,
• A. Sala and
• A. Locatelli

Beilstein J. Nanotechnol. 2014, 5, 1873–1886, doi:10.3762/bjnano.5.198

• . In the above example of FeOx growth on Ru(0001), further oxidation by using NO2 as atomic oxygen source resulted in the transformation of the FeO wetting layer to hematite (α-Fe2O3) and the triangular Fe3O4 islands to maghemite (γ-Fe2O3) [71]. In an independent study, the real-time observation of

Influence of surface-modified maghemite nanoparticles on in vitro survival of human stem cells

• Michal Babič,
• Daniel Horák,
• Lyubov L. Lukash,
• Tetiana A. Ruban,
• Yurii N. Kolomiets,
• Svitlana P. Shpylova and
• Oksana A. Grypych

Beilstein J. Nanotechnol. 2014, 5, 1732–1737, doi:10.3762/bjnano.5.183

• Molecular Biology and Genetics, NAS of Ukraine, Zabolotnogo 150, 03143 Kiev, Ukraine 10.3762/bjnano.5.183 Abstract Surface-modified maghemite (γ-Fe2O3) nanoparticles were obtained by using a conventional precipitation method and coated with D-mannose and poly(N,N-dimethylacrylamide). Both the initial and

• -mannose- and poly(N,N-dimethylacrylamide)-coated γ-Fe2O3 particles exhibit much lower level of cytotoxicity than the non-coated γ-Fe2O3. Keywords: maghemite; magnetic; MTT assay; nanoparticles; stem cells; Introduction One of the most important applications of nanoparticles in biomedicine is the direct

• (magnetite Fe3O4 or maghemite γ-Fe2O3) are their simple preparation and their magnetic properties, which are necessary for detection. Moreover, it is convenient that iron oxides are readily metabolized in the body. From this point of view, quantum dots are disqualified due to their toxicity. Like in every

Manipulation of isolated brain nerve terminals by an external magnetic field using D-mannose-coated γ-Fe₂O₃ nano-sized particles and assessment of their effects on glutamate transport

• Tatiana Borisova,
• Natalia Krisanova,
• Arsenii Borуsov,
• Roman Sivko,
• Ludmila Ostapchenko,
• Michal Babic and
• Daniel Horak

Beilstein J. Nanotechnol. 2014, 5, 778–788, doi:10.3762/bjnano.5.90

• in nano-neurotechnology. D-Mannose-coated superparamagnetic nanoparticles were synthesized by coprecipitation of Fe(II) and Fe(III) salts followed by oxidation with sodium hypochlorite and addition of D-mannose. Effects of D-mannose-coated superparamagnetic maghemite (γ-Fe2O3) nanoparticles on key

• characteristics of the glutamatergic neurotransmission were analysed. Using radiolabeled L-[14C]glutamate, it was shown that D-mannose-coated γ-Fe2O3 nanoparticles did not affect high-affinity Na+-dependent uptake, tonic release and the extracellular level of L-[14C]glutamate in isolated rat brain nerve terminals

• (synaptosomes). Also, the membrane potential of synaptosomes and acidification of synaptic vesicles was not changed as a result of the application of D-mannose-coated γ-Fe2O3 nanoparticles. This was demonstrated with the potential-sensitive fluorescent dye rhodamine 6G and the pH-sensitive dye acridine orange

Thermal stability and reduction of iron oxide nanowires at moderate temperatures

• Annalisa Paolone,
• Marco Angelucci,
• Stefania Panero,
• Maria Grazia Betti and
• Carlo Mariani

Beilstein J. Nanotechnol. 2014, 5, 323–328, doi:10.3762/bjnano.5.36

• transmittance between 500 and 650 cm−1 and the broad phonon band centered around 950 cm−1. However, we can observe a minimum of the transmittance around 700 cm−1, which is a fingerprint of maghemite (γ-Fe2O3) [27]. Thus, the clean sample 2 presents features that are typical of a mixture of α- and γ-Fe2O3. The

• , Fe3O4 [27]. The evolution of the infrared spectra with temperature indicates that in the pristine α-Fe2O3 material, there is a minor contribution of γ-Fe2O3, the concentration of which remains practically unchanged when the sample is heated to about 470 K, but increases significantly after a thermal

Magnetic interactions between nanoparticles

• Steen Mørup,
• Mikkel Fougt Hansen and
• Cathrine Frandsen

Beilstein J. Nanotechnol. 2010, 1, 182–190, doi:10.3762/bjnano.1.22

• , including Fe100−xCx [10], ε-Fe3N [11], γ-Fe2O3 [12][13][14] and Fe3O4 [15] have been investigated. If the particles are randomly distributed and have a random orientation of the easy axes, the magnetic properties can have similarities to those of spin glasses [10][11][14], and therefore these interacting

• , however, remarkable that weak dipole interactions can result in faster superparamagnetic relaxation. This has been observed in Mössbauer studies of maghemite (γ-Fe2O3) nanoparticles [12][28], and the effect has been explained by a lowering of the energy barriers between the two minima of the magnetic

Magnetic nanoparticles for biomedical NMR-based diagnostics

• Huilin Shao,
• Tae-Jong Yoon,
• Monty Liong,
• Ralph Weissleder and
• Hakho Lee

Beilstein J. Nanotechnol. 2010, 1, 142–154, doi:10.3762/bjnano.1.17

• ][37][38][39][40][41][42]. CLIO nanoparticles contain a superparamagnetic iron oxide core (3–5 nm monocrystalline iron oxide) composed of ferrimagnetic magnetite (Fe3O4) and/or maghemite (γ-Fe2O3). The metallic core is subsequently coated with biocompatible dextran, before being cross-linked with

Magnetic coupling mechanisms in particle/thin film composite systems

• Giovanni A. Badini Confalonieri,
• Philipp Szary,
• Durgamadhab Mishra,
• Maria J. Benitez,
• Mathias Feyen,
• An Hui Lu,
• Leonardo Agudo,
• Gunther Eggeler,
• Oleg Petracic and
• Hartmut Zabel

Beilstein J. Nanotechnol. 2010, 1, 101–107, doi:10.3762/bjnano.1.12

• Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany Institut für Werkstoffe, Ruhr-Universität Bochum, D-44780 Bochum, Germany 10.3762/bjnano.1.12 Abstract Magnetic γ-Fe2O3 nanoparticles with a mean diameter of 20 nm and size distribution of 7% were chemically synthesized and spin-coated on top of a Si

• magnetic force microscopy. Moreover, an exchange bias effect was found, which is likely to be due to oxygen exchange between the iron oxide and the Co layer, and thus forming of an antiferromagnetic CoO layer at the γ-Fe2O3/Co interface. Keywords: exchange bias; iron oxide nanoparticles; nanoparticle self

• samples were annealed at 170 °C for 20 min in air in order to obtain mainly single phase maghemite (γ-Fe2O3) NPs as reported in Ref. [41]. After heat treatment, the NP monolayer was ion-milled with neutralized Ar-ions for 4 min in order to flatten the NP array and remove the oleic acid layer. Finally, a

Uniform excitations in magnetic nanoparticles

• Steen Mørup,
• Cathrine Frandsen and
• Mikkel Fougt Hansen

Beilstein J. Nanotechnol. 2010, 1, 48–54, doi:10.3762/bjnano.1.6

• magnetic anisotropy [14]. A similar size dependence of the magnetic anisotropy constant has been found by Mössbauer studies in other nanoparticles, for example, maghemite (γ-Fe2O3) [15], hematite (α-Fe2O3) [16] and metallic iron (α-Fe) [17]. If a sufficiently large magnetic field B is applied, such that B