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

• microemulsion methods. Cerium–fluoride-doped terbium(III) NPs represented the luminescent part and Fe3O4 NPs were used as magnetic core. Both these nanostructures were trapped inside a silica shell, which acted as inert oxide. The synthesis involved simultaneous addition of luminescent NPs (CeF3:Tb3+) and

• magnetic materials (Fe3O4 NPs) inside silica shell in the presence of TEOS (Figure 3). The prepared NPs were characterized by XRD, TEM and fluorescence spectroscopy. The TEM images confirmed homogenous distribution of NPs of sizes 30–50 nm. When excited at 254 nm, the hybrid rare earth nanocomposites

• . The magnetic NPs (Fe3O4) were prepared by Massart’s method and finally these were coated with a silica layer by using TEOS. Further these Fe3O4@SiO2 NPs were encapsulated inside silica-coated luminescent Ru(bpy)32+ shells (Ru(bpy)3 = tris(2,2'-bipyridyl)ruthenium(II) dichloride hexahydrate). The TEM

Comparative evaluation of the impact on endothelial cells induced by different nanoparticle structures and functionalization

• Lisa Landgraf,
• Ines Müller,
• Peter Ernst,
• Miriam Schäfer,
• Christina Rosman,
• Isabel Schick,
• Oskar Köhler,
• Hartmut Oehring,
• Vladimir V. Breus,
• Thomas Basché,
• Carsten Sönnichsen,
• Wolfgang Tremel and
• Ingrid Hilger

Beilstein J. Nanotechnol. 2015, 6, 300–312, doi:10.3762/bjnano.6.28

• MnO and Fe3O4, again, those with an elongated shape (Au@MnO and Au@Fe3O4, Figure 1b and Figure 1c) led to a stronger reduction of ATP levels than the spherical ones in a time-dependent manner. In general, the MnO-based nanoparticles and nanoparticles with NH2-functionalization had a stronger impact on

• cell metabolism than the Fe3O4 variants or the formulations without NH2-functionalization. The mentioned relationships could be attributed to the positively charged surface (NH2), which has been reported to induce damages on the cell membranes (APTMS-coated nanoparticles [47]). To conclude, among the

• microscopy (TEM) investigations were performed. Spherical CTAB-modified gold nanoparticles with a size of 40 nm were localized in vacuoles after 1 h of incubation (Figure 5a). After a 1 h treatment of cells only, Au-NH2@Fe3O4 (20 nm) and spherical Au (4 nm) nanoparticles were shown to be internalized into

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

• (Ca6B6O11∙5H2O), for the first time by means of CVD [58]. The reaction parameters such as type of catalyst, colemanite/catalyst ratio, reaction temperature and duration were optimized. ZnO, Al2O3, Fe3O4 and Fe2O3 catalysts were investigated with respect to their differences in performance. It was found that

Inorganic Janus particles for biomedical applications

• Isabel Schick,
• Steffen Lorenz,
• Dominik Gehrig,
• Stefan Tenzer,
• Wiebke Storck,
• Karl Fischer,
• Dennis Strand,
• Frédéric Laquai and
• Wolfgang Tremel

Beilstein J. Nanotechnol. 2014, 5, 2346–2362, doi:10.3762/bjnano.5.244

• building blocks, and makes these particles of particular importance. Binks and co-workers [31] predicted a strengthened adsorption at an oil–water interface due to the increase in surface activity by a factor of three of a Janus. Glaser et al. [32] demonstrated that Au@Fe3O4 Janus particles reduce the

• active component toward metal-organic reactions. For instance, this enhanced catalytic activity in comparison to the single component nanoparticles was demonstrated for Ni@Fe2O3 [45] or Pt@Fe3O4 [46]. Furthermore, the magnetic anisotropy and coercivity of Fe3O4 was significantly increased due to

• conjugation to Ag nanoparticles when combined to form Ag@Fe3O4 dumbbell-like hetero-nanoparticles [47]. Moreover, plasmonic photocatalysts combine two prominent features: a Schottky junction enhancing charge separation and surface plasmon resonance, which is responsible for strong absorption of visible light

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

• micrometer-sized Fe3O4 islands on a FeO wetting layer. The combination of spatially-resolved XPS and XAS spectra, along with μ-LEED patterns, allowed the unequivocal identification of the specific iron-oxide phases. From the screening of substrate core-level photoelectrons, the thickness of the micrometer

• ). This observation corresponds to the thinnest magnetite crystal that shows magnetism. Beyond the self-organized crystal shapes at the micrometer scale, epitaxial iron-oxide films provide a variety of complex surface reconstructions at the atomic scale as usual for oxide surfaces [74]. Fe3O4 films on Pt

• (111) are known to give a (2 × 2) reconstruction with an additional moiré superstructure. Nevertheless, the details of the Fe3O4 surface structure is still under study. The recent work by using an aberration-corrected XPEEM-LEEM setup, SMART (BESSY II, Helmholtz Zentrum, Berlin), showed distinct

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

• (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

A sonochemical approach to the direct surface functionalization of superparamagnetic iron oxide nanoparticles with (3-aminopropyl)triethoxysilane

• Bashiru Kayode Sodipo and
• Azlan Abdul Aziz

Beilstein J. Nanotechnol. 2014, 5, 1472–1476, doi:10.3762/bjnano.5.160

• the band of Fe 2p3/2 and Fe 2p1/2 (Supporting Information File 1, Figure S5) that appears at 725.25 eV and 711.85 eV, respectively. The difference in their energy is 13.4 eV, which corresponds to 13.6 eV of Fe2O3 or Fe3O4. However, the XPS result alone cannot be used to determine the oxidation state

• of Fe in Fe2O3 or Fe3O4. This is due to similarity in the oxidation state of both iron oxide compounds. The chemical shifts observed in all the bands can be ascribed to the binding of the APTES on the SPION. The XRD pattern of the silanized SPION is shown in Figure 3. It corresponds to the JCPDS

Antimicrobial nanospheres thin coatings prepared by advanced pulsed laser technique

• Alina Maria Holban,
• Valentina Grumezescu,
• Alexandru Mihai Grumezescu,
• Bogdan Ştefan Vasile,
• Roxana Truşcă,
• Rodica Cristescu,
• Gabriel Socol and
• Florin Iordache

Beilstein J. Nanotechnol. 2014, 5, 872–880, doi:10.3762/bjnano.5.99

• -chitosan-magnetite-eugenol (PLA-CS-Fe3O4@EUG) nanospheres by matrix assisted pulsed laser evaporation (MAPLE). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) investigation proved that the homogenous Fe3O4@EUG nanoparticles have an average diameter of about 7 nm, while the PLA

• -CS-Fe3O4@EUG nanospheres diameter sizes range between 20 and 80 nm. These MAPLE-deposited coatings acted as bioactive nanosystems and exhibited a great antimicrobial effect by impairing the adherence and biofilm formation of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa

• and coatings of soft materials, organic and polymeric materials, and complex molecules [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Furthermore, the compatibility of MAPLE processing has been demonstrated for inorganic systems such as TiO2 [36], and Fe3O4 nanoparticle-based

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

• of iron salts, namely FeCl2 and FeCl3, by rapid increase of pH by ammonia. Similarly as described in [12], this was followed by the oxidation of the resulting magnetite (Fe3O4) with sodium hypochlorite producing maghemite (γ-Fe2O3), which is chemically more stable than Fe3O4. This is in contrast to

Carbon dioxide hydrogenation to aromatic hydrocarbons by using an iron/iron oxide nanocatalyst

• Hongwang Wang,
• Jim Hodgson,
• Tej B. Shrestha,
• Prem S. Thapa,
• David Moore,
• Xiaorong Wu,
• Myles Ikenberry,
• Deryl L. Troyer,
• Donghai Wang,
• Keith L. Hohn and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2014, 5, 760–769, doi:10.3762/bjnano.5.88

• ) employing Fe/Fe3O4 nanoparticles as catalyst. The synthesis of the catalyst and the mechanism of CO2-hydrogenation will be discussed, as well as further applications of Fe/Fe3O4 nanoparticles in catalysis. Keywords: aromatic hydrocarbons; carbon dioxide reduction; heterogenous catalysis; iron/iron oxide

• oxygen reduction reaction [46][47][48] have been reported. Synthesis of Fe/Fe3O4 nanoparticles Here we report the selective formation of aromatic hydrocarbons from CO2 hydrogenation reactions catalyzed by an Fe/Fe3O4 nanocatalyst. Recently, Sun’s group reported a facile method for synthesizing highly

• crystalline Fe/Fe3O4 nanoparticles [49]. These nanoparticles were found to be robust against deep oxidation because of the formation of a protective crystalline Fe3O4 shell upon the direct oxidation of the bcc-Fe core. The synthesis of the Fe/Fe3O4 nanoparticles was slightly modified and scaled up by a factor

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

• , infrared and photoemission spectroscopy measurements. Results: The chemical state of the nanowires is typical of the Fe2O3 phase and the stoichiometry changes towards a Fe3O4 phase by annealing above 440 K. The shape and morphology of the nanowires is not modified by moderate thermal treatment, as imaged

• +) with a high chemical stability, while the mixed chemical state of Fe3O4 (Fe2+/3+) might induce instabilities during its use as electrode material. In the present work, we present a spectroscopic and morphologic characterization of Fe2O3 nanowires (NWs), which were produced by means of a hard template

• . Thermogravimetry measurements distinctly show the mass reduction due to oxygen loss, and infrared transmittance and core-level photoemission measurements allow to follow the reduction process of the iron ions at different temperatures, showing the chemical reduction to Fe3O4 starting at moderate temperatures

En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

• Slawomir Boncel,
• Sebastian W. Pattinson,
• Valérie Geiser,
• Milo S. P. Shaffer and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2014, 5, 219–233, doi:10.3762/bjnano.5.24

• phases accompanying the nanotubes. The most intensive reflections at 2θ = 42.9, 44.7 and 49.9° could be assigned to α-Fe (110) and γ-Fe (111, 200), respectively. The peak at 2θ = 35°, of the second highest intensity, matches several iron oxides, i.e., FeO, Fe2O3 and Fe3O4. The iron oxides in all of their

Synthesis of boron nitride nanotubes from unprocessed colemanite

• Saban Kalay,
• Zehra Yilmaz and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2013, 4, 843–851, doi:10.3762/bjnano.4.95

• catalyst. For this purpose Fe, Al or Mg are widely used in the synthesis of BNNT [3][6]. In this study, four types of catalysts, namely ZnO, Al2O3, Fe3O4, and Fe2O3, were investigated for their performances. Figure 1a–d shows 4 SEM images of reaction mixtures under the same experimental conditions but each

• difference, they do not effectively interact with NH3 gas. Therefore, no BNNT formation was observed. However, when iron oxides were used as catalysts, the formation of BNNTs was dramatically improved. The BNNTs synthesized with the use of Fe3O4 (Figure 1c) or Fe2O3 (Figure 1d) are clearly seen in the

• reaction mixtures on the SEM images. When Fe3O4 was used, the diameter of the BNNTs was dramatically increased and zigzag structures with shorter length were observed as seen in Figure 1c. When Fe2O3 was used, a lot of BNNTs with linear but smaller lengths was obtained (Figure 1d). This clearly indicates

A facile synthesis of a carbon-encapsulated Fe₃O₄ nanocomposite and its performance as anode in lithium-ion batteries

• Raju Prakash,
• Katharina Fanselau,
• Shuhua Ren,
• Tapan Kumar Mandal,
• Christian Kübel,
• Horst Hahn and
• Maximilian Fichtner

Beilstein J. Nanotechnol. 2013, 4, 699–704, doi:10.3762/bjnano.4.79

• -von-Helmholtz-Platz 1, Karlsruhe, 76344, Germany Helmholtz Institute Ulm (HIU), Albert-Einstein-Allee 11, Ulm, 89081, Germany 10.3762/bjnano.4.79 Abstract A carbon-encapsulated Fe3O4 nanocomposite was prepared by a simple one-step pyrolysis of iron pentacarbonyl without using any templates, solvents

• or surfactants. The structure and morphology of the nanocomposite was investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis and Raman spectroscopy. Fe3O4 nanoparticles are dispersed intimately in a carbon framework. The

• nanocomposite exhibits well constructed core–shell and nanotube structures, with Fe3O4 cores and graphitic shells/tubes. The as-synthesized material could be used directly as anode in a lithium-ion cell and demonstrated a stable capacity, and good cyclic and rate performances. Keywords: electrochemistry; iron

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

• 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 and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2012, 3, 444–455, doi:10.3762/bjnano.3.51

• 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

• and by activating the immune system. Keywords: cell-based delivery; chemotherapeutic prodrug; magnetic Fe/Fe3O4 nanoparticles; SN38; Introduction Irinotecan (CPT-11) is a potent chemotherapeutic prodrug against various types of cancer, such as colorectal, lung, and ovarian cancer [1][2][3][4][5]. It

• , biocompatibility, and potential for targeted accumulation at the tumor site, ultra-small magnetic nanoparticles are the prime candidates for application in magnetic hyperthermia [32][33][34]. We have developed a magnetic core/shell Fe/Fe3O4 nanoparticle platform, which can generate substantial heat within a

Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

• Armin Kleibert,
• Wolfgang Rosellen,
• Mathias Getzlaff and
• Joachim Bansmann

Beilstein J. Nanotechnol. 2011, 2, 47–56, doi:10.3762/bjnano.2.6

•  1b. The side view in the inset shows compact particles with mostly cubic shapes due to the partial oxidation. Electron diffraction reveals the presence of metallic bcc Fe and Fe oxides as, e.g., Fe3O4 [27]. A size distribution of the oxidized Fe particles displayed in Figure 1b is given in Figure 1c

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

• ferromagnetic cobalt covered by a shell of antiferromagnetic CoO [4]: This effect is nowadays utilized in read heads in computer hard disk drives. In a neutron study of Fe3O4/CoO multilayers, van der Zaag et al. [5] found that the Néel temperature of CoO was enhanced due to the exchange interaction with

• ferrimagnetic Fe3O4 layers with a Curie temperature of about 850 K. Similarly, an increase of the Curie temperature of ferrimagnetic γ-Mn2O3 due to interaction with antiferromagnetic MnO has been found in MnO/γ-Mn2O3 core–shell particles [6]. The magnetic properties of non-interacting magnetic nanoparticles are

• , 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

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

• coupled Fe3O4/CoO [38] and Fe/CoO [39] thin film systems, that the blocking temperature, in this case the temperature at which exchange bias between a FM and an AF thin film disappears, can occur at temperatures below the Néel temperature of CoO (~290 K), in the case of ultra thin films of CoO (less than

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

• Equation 1, and the latter approximation is valid at low temperatures. The linear temperature dependence of the magnetization in nanoparticles was first observed by Mössbauer spectroscopy studies of magnetite (Fe3O4) nanoparticles [3], but it has later been studied in nanoparticles of several other

• the relaxation is fast compared to the timescale of Mössbauer spectroscopy, and the observed magnetic hyperfine field is then given by where B0 is the saturation hyperfine field. Figure 3 shows the temperature dependence of the magnetic hyperfine field of three samples of magnetite (Fe3O4