Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

• Andrey V. Nomoev,
• Sergey P. Bardakhanov,
• Makoto Schreiber,
• Dashima G. Bazarova,
• Nikolai A. Romanov,
• Boris B. Baldanov,
• Bair R. Radnaev and
• Viacheslav V. Syzrantsev

Beilstein J. Nanotechnol. 2015, 6, 874–880, doi:10.3762/bjnano.6.89

• University, Pirogova street 2, Novosibirsk, 630090, Russia 10.3762/bjnano.6.89 Abstract The structure of core–shell Cu@silica and Ag@Si nanoparticles obtained in one-step through evaporation of elemental precursors by a high-powered electron beam are investigated. The structure of the core and shell of the

• differences in the vapour concentration of the two components. Keywords: core–shell; electron beam evaporation; gas phase; mechanism of formation; one-step; Introduction Core–shell type nanoparticles are a type of biphasic materials which have an inner core structure and an outer shell made of different

• of the core material or to use an inexpensive core material to carry a thin, more-expensive shell material [1][2]. Thus, they have found wide applicability in fields such as biomedicine, electrical and semiconducting materials, and catalysts [1][2]. The majority of core–shell particles are

Combination of surface- and interference-enhanced Raman scattering by CuS nanocrystals on nanopatterned Au structures

• Alexander G. Milekhin,
• Nikolay A. Yeryukov,
• Larisa L. Sveshnikova,
• Tatyana A. Duda,
• Ekaterina E. Rodyakina,
• Victor A. Gridchin,
• Evgeniya S. Sheremet and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2015, 6, 749–754, doi:10.3762/bjnano.6.77

• observed in core–shell CdSe/ZnS NCs deposited on commercially available nanostructured Au substrates [3]. Later, the SERS effect by LO phonons in CdSe in CdSe/ZnS NCs was realized on non-ordered nanostructured Ag surfaces [4]. Very recently, Lee et al. [5] reported the observation of SERS by surface

• optical (SO) and LO phonon modes in a CdSe core and the transverse optical (TO) phonon mode in a ZnS shell of core–shell CdSe/ZnS NCs attached to the surface of a Au nanowire. The spectrum of optical and interface phonons was obtained from the analysis of SERS spectra of pure CdSe NCs, core–shell CdSe/CdS

Simple approach for the fabrication of PEDOT-coated Si nanowires

• Mingxuan Zhu,
• Marielle Eyraud,
• Judikael Le Rouzo,
• Nadia Ait Ahmed,
• Florence Boulc’h,
• Claude Alfonso,
• Philippe Knauth and
• François Flory

Beilstein J. Nanotechnol. 2015, 6, 640–650, doi:10.3762/bjnano.6.65

• electrochemical methods. Since the polymerization reaction is a very fast process with regards to monomer diffusion along the SiNW, the conformal deposition by classical, fixed potential deposition was not favored. Instead, the core–shell heterojunction structure was finally achieved by a pulsed deposition method

• . An extremely large shunt resistance was exhibited and determined to be related to the diffusion conditions occurring during polymerization. Keywords: conductive polymer; core–shell structure; electrodeposition; hybrid material; SiNW; Introduction Silicon nanowires (SiNWs) are a current, active

• visible spectrum can be achieved for SiNWs [8]. As far as the device fabrication is concerned, a core–shell arrangement of p–n junction forming materials is promising for the optimization of the electronic charge collection capability. This is due to the nature of the core–shell structure, which allows

Overview of nanoscale NEXAFS performed with soft X-ray microscopes

• Peter Guttmann and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2015, 6, 595–604, doi:10.3762/bjnano.6.61

• thin film devices (SrTiO3) could be demonstrated [64]. The change of resistance in a RRAM device could be assigned to a redox-process. The switching filament could be allocated to extended growth defects which are already present in the virgin films. Synthesis of anisotropic core-shell Fe3O4@Au

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

• . Similarly, Koole et al. [20] reported a procedure for the preparation of highly monodispersed silica particles with single core–shell–shell CdSe QDs incorporated into the center and paramagnetic Gd-DTPA-DSA [Gd-DTPA-bis(stearylamide)] in the lipid coating. The NPs were characterized by TEM, DLS and

• material composed of silica coated iron oxide NPs and Ru(bpy) complex for multimodal imaging. Such strategies were also followed by Hu et al. [30], Mi et al. [31] (Figure 4). Wu et al. [32] reported the synthesis of a hybrid nanocomposite material composed of Ru(bpy)-doped silica core–shell NPs and Pas

• followed by Chen et al. [36]. 2.6 Iron oxide as magnetic and QDs as fluorescent probe He et al. [37] reported a reverse microemulsion method for the synthesis of core–shell fluorescent magnetic silica-coated NPs. The Fe3O4 NPs were prepared by using FeCl3 and FeSO4 salts following co-precipitation method

Conformal SiO₂ coating of sub-100 nm diameter channels of polycarbonate etched ion-track channels by atomic layer deposition

• Nicolas Sobel,
• Christian Hess,
• Manuela Lukas,
• Anne Spende,
• Bernd Stühn,
• M. E. Toimil-Molares and
• Christina Trautmann

Beilstein J. Nanotechnol. 2015, 6, 472–479, doi:10.3762/bjnano.6.48

• the SAXS profiles with a cylindrical core–shell model for statistically distributed pores [35] allows us to deduce the inner and outer pore diameter and thus the thickness of the ALD-deposited SiO2 layer (Table 3). Additional parameters of the analysis are the polydispersity of the pores (6–8%), the

Influence of size, shape and core–shell interface on surface plasmon resonance in Ag and Ag@MgO nanoparticle films deposited on Si/SiO_x

• Sergio D’Addato,
• Daniele Pinotti,
• Maria Chiara Spadaro,
• Guido Paolicelli,
• Vincenzo Grillo,
• Sergio Valeri,
• Luca Pasquali,
• Luca Bergamini and
• Stefano Corni

Beilstein J. Nanotechnol. 2015, 6, 404–413, doi:10.3762/bjnano.6.40

• of Electricity and Electronics, Faculty of Science and Technology, UPV/EHU, 48080 Bilbao, Spain Materials Physics Center CSIC-UPV/EHU and Donostia International Physics Center DIPC, Paseo Manuel Lardizabal 4, 20018 Donostia-San Sebastian, Spain 10.3762/bjnano.6.40 Abstract Ag and Ag@MgO core–shell

• classical electrodynamics simulations by treating the NP-containing layer as an effective Maxwell Garnett medium. The simulations gave results in agreement with the experiments when accounting for the experimentally observed aggregation. Keywords: Ag; core–shell nanoparticles; electron microscopy; MgO

• , resulting in a core–shell structure with independently controlled core size and shell thickness [19][23][24]. This method was also used to produce a non-native oxide shell and to study the evolution of the physical properties of the NP assemblies with increasing shell thickness, owing to a configuration

Biological responses to nanoscale particles

• Reinhard Zellner

Beilstein J. Nanotechnol. 2015, 6, 380–382, doi:10.3762/bjnano.6.37

• conjugates of biomolecules, magnetism, radioactivity, Janus particles and core–shell particles were combined. In particular, the use of fluorescently labeled particles has become one of the preferred tools to track nanoparticles inside cells and tissue. When nanoparticles are exposed to biological fluids

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

• further functionalization three different ligands for CdSe/4 ZnS core–shell QDs (d = 5.4 nm) were selected: 3-mercaptopropionic acid/MPA (COOH), cysteamine/CyA (NH2), D-penicillamine/DPA (NH2/COOH). These coatings represent neutral, positive or negative charge and provide the solubility in water. The

• Endothelial cells (SVEC4-10) were harvested from culture dishes and seeded in an 8-well electrode array at the density of 60.000 cells/well (equates confluency) at 37 °C in a humidified 5% CO2 environment. Exchange of culture medium with medium containing CdSe/4ZnS core-shell QDs (with CyA, MPA, DPA) was

The effect of surface charge on nonspecific uptake and cytotoxicity of CdSe/ZnS core/shell quantum dots

• Vladimir V. Breus,
• Anna Pietuch,
• Marco Tarantola,
• Thomas Basché and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 281–292, doi:10.3762/bjnano.6.26

• -Planck-Institute for Dynamics and Self-Organization (MPIDS), Laboratory for Fluid Dynamics, Pattern Formation and Biocomplexity, Am Fassberg 17, 37077 Goettingen, Germany 10.3762/bjnano.6.26 Abstract In this work, cytotoxicity and cellular impedance response was compared for CdSe/ZnS core/shell quantum

• classical cytotoxicity tests do not recognize QD-induced damage. We expose the cells to solutions of CdSe/ZnS core/shell QDs, functionalized with cysteamine (CA), dihydrolipoic acid (DHLA) and D-penicillamine (DPA), producing positively-charged, negatively-charged and zwitterionic particle surfaces

• cooled down to room temperature with compressed air flow. The resulting core/shell QDs were precipitated with ethanol, centrifuged and redissolved in chloroform. QD surface functionalization Table 1 summarizes the amounts of ligands and solvents used for QD surface functionalization. The amount of

Tailoring the ligand shell for the control of cellular uptake and optical properties of nanocrystals

• Johannes Ostermann,
• Christian Schmidtke,
• Christopher Wolter,
• Jan-Philip Merkl,
• Hauke Kloust and
• Horst Weller

Beilstein J. Nanotechnol. 2015, 6, 232–242, doi:10.3762/bjnano.6.22

• has shown to drastically enhance the fluorescence properties, namely the fluorescence quantum efficiency, of encapsulated CdSe/CdS/ZnS and CdSe/CdxZn(1-x)S/ZnS core–shell–shell quantum dots (QDs). This enhancement can be explained to a certain extent by the cross-linking of the micelles but further

The distribution and degradation of radiolabeled superparamagnetic iron oxide nanoparticles and quantum dots in mice

• Denise Bargheer,
• Artur Giemsa,
• Barbara Freund,
• Markus Heine,
• Christian Waurisch,
• Gordon M. Stachowski,
• Stephen G. Hickey,
• Alexander Eychmüller,
• Jörg Heeren and
• Peter Nielsen

Beilstein J. Nanotechnol. 2015, 6, 111–123, doi:10.3762/bjnano.6.11

• the iron oxide core of SPIOs under similar experimental conditions was unsuccessful. However, a distinct incorporation of 65ZnCl2 occurred when CdSe/CdS/ZnS core/shell/shell quantum dots were synthesized (Figure 1). Both hydrophobic nanoparticle cores were encapsulated using the same polymer to render

• the present study the outer ZnS shell of CdSe/CdS/ZnS (core/shell/shell) quantum dots was labeled by incubation with water-free 65Zn2+ in an organic solvent. This radionuclide is a hard γ-emitter (1.1 MeV), which would allow precise measurement even in living animals using a whole body counter

• around 70% of the injected dose present (Figure 7A). This is in good agreement with the results from Sun et al. [32] and supports the reliability of our label results. When CdSe/CdS/ZnS (core/shell/shell) quantum dots are degraded in vivo, the outer shell will be dissolved first and zinc will be released

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

• area of the BNNTs, it was concluded that the constructed structure was ideal for drug delivery purposes [83]. The core–shell structures of BNNTs with europium-doped, sodium gadolinium fluoride (NaGdF4:Eu) were fabricated by using urea to demonstrate the chemotherapy efficiency of the BNNT–NaGdF4:Eu

Morphology, structural properties and reducibility of size-selected CeO_2−x nanoparticle films

• Maria Chiara Spadaro,
• Sergio D’Addato,
• Gabriele Gasperi,
• Francesco Benedetti,
• Paola Luches,
• Vincenzo Grillo,
• Giovanni Bertoni and
• Sergio Valeri

Beilstein J. Nanotechnol. 2015, 6, 60–67, doi:10.3762/bjnano.6.7

• = 1020 K, is shown. In the spectrum it is possible to observe features from both Ce3+ and Ce4+ ionic species, as already observed for ceria NPs. In fact a core–shell model was proposed [24][25] for the oxidation state of the CeO2−x NPs, which assumes that the core of the nanoparticle is composed of CeO2

Size-dependent density of zirconia nanoparticles

• Agnieszka Opalinska,
• Iwona Malka,
• Wojciech Dzwolak,
• Tadeusz Chudoba,
• Adam Presz and
• Witold Lojkowski

Beilstein J. Nanotechnol. 2015, 6, 27–35, doi:10.3762/bjnano.6.4

• , its thickness can be estimated by the fitting function of the effective density versus grain size. The following formula expresses the effective powder density as a function of core/shell densities, their thicknesses, and the grain size: where ρ1 is density of the core, ρ2 is the density of the shell

Bright photoluminescence from ordered arrays of SiGe nanowires grown on Si(111)

• D. J. Lockwood,
• N. L. Rowell,
• A. Benkouider,
• A. Ronda,
• L. Favre and
• I. Berbezier

Beilstein J. Nanotechnol. 2014, 5, 2498–2504, doi:10.3762/bjnano.5.259

• have been demonstrated for specific core/shell NW configurations with an ultimate control over the NW shape, aspect ratio and radial multishell composition [7]. A major asset of Si/Ge core/shell [8] and axial [9] NW heterostructures is also their ease of integration in CMOS technology, which allows the

• Au0.18Si0.82 catalysts. The main advantage of this growth method is the control of the NW position (related to site selectivity) and its size; a homogeneous size is obtained due to the regular network of Au nanocrystals (see Figure 2). Also, SiGe NWs can be grown and then transformed in a second step into core

• -shell NWs using a condensation process that we have developed. Three NW samples were prepared for this study: Sample (A), where the NWs are grown randomly across the Si substrate; sample (B), where the nanowires decorate the edges of 400 × 400 µm2 boxes; and sample (C), where the NWs fill 400 × 400 µm2

Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

• Rudolf Herrmann,
• Markus Rennhak and
• Armin Reller

Beilstein J. Nanotechnol. 2014, 5, 2413–2423, doi:10.3762/bjnano.5.251

• and characterization of fluorescent silica and ceria nanoparticles. Synthetic methods for labelling of silica and polyorganosiloxane/silica core–shell nanoparticles with perylenediimide derivatives are described, as well as the modification of the shell with thiol groups. Photometric methods for the

• ; silica core-shell nanoparticles; Review Within the general goal of the DFG priority programme SPP 1313, to study the unintended exposure of intended nanoparticles to biological systems, we decided to focus our research on oxidic nanoparticles (NP) applied technically in large scale, in particular silica

• primary shell can now be enlarged by a secondary shell in a reaction with TEOS under Stöber conditions. The final core-shell NP have total diameters in the range of 30 ± 11–100 ± 25 nm with a fluorescent core of 10 ± 3–30 ± 9 nm. A typical TEM picture is shown in Figure 4 (left). The amount of dye

Nanoparticle interactions with live cells: Quantitative fluorescence microscopy of nanoparticle size effects

• Li Shang,
• Karin Nienhaus,
• Xiue Jiang,
• Linxiao Yang,
• Katharina Landfester,
• Volker Mailänder,
• Thomas Simmet and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2388–2397, doi:10.3762/bjnano.5.248

• with widely differing sizes. We have selected very small gold nanoclusters (AuNCs, diameter ≈3 nm) stabilized with dihydrolipoic acid (DHLA), semiconductor core-shell quantum dots (CdSe/ZnS, ≈10 nm) coated with D-penicillamine (DPA) and relatively large polystyrene (PS) NPs (≈100 nm) with different

• sodium phosphate, Invitrogen, Carlsbad, CA) for later use. DPA-QDs were prepared as previously described [28]. Briefly, CdSe/ZnS core/shell QDs were synthesized in organic solvent prior to ligand exchange with DPA, yielding water-soluble zwitterionic QDs. All PS NPs, labeled with the fluorescent dye N

Synthesis of radioactively labelled CdSe/CdS/ZnS quantum dots for in vivo experiments

• Gordon M. Stachowski,
• Christoph Bauer,
• Christian Waurisch,
• Denise Bargheer,
• Peter Nielsen,
• Jörg Heeren,
• Stephen G. Hickey and
• Alexander Eychmüller

Beilstein J. Nanotechnol. 2014, 5, 2383–2387, doi:10.3762/bjnano.5.247

• Bawendi and co-workers, which focused particularly on the synthesis of II–VI materials [1][2][3][4][5]. CdSe-based, state-of-the-art synthetic protocols typically use the hot injection method [1] and can deliver QDs with visible emission which possess quantum yields (QYs) of up to 85% as core/shell or

• present in the synthesis with their equivalent radionuclides. In the past, radionuclides such as 109Cd or 111In were used for intrinsic radiolabeling [12][13]. In this work, the Zn component of CdSe/CdS/ZnS core/shell/shell QDs was selected for replacement with 65Zn due to its ease of availability

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

• nanoparticles are core/shell structures, in particular core/shell structures of fluorescent II–IV and III–V semiconductors, typically transition metal-chalcogenides, -phosphides, and -arsenides [10]. The epitaxial combination of a 0D spherical quantum dot with a 1D rod-like shell of a semiconductor leads to

• important synthetic methods focusing on heterogeneous nucleation, which facilitates the control of size and morphology of particles varying from dumbbell-like structures to nanoflowers or core/shell structures. Recent synthetic developments have made promises for applying Janus particles due to their

• exploration of their physicochemical properties and large scale applications in the near future. Illustrations of the transition from isotropic to anisotropic particles. a) Evolution of the PL-peak position, b) schematic representation, and c) evolution of the PL-quantum yield for several core-shell quantum

Influence of the supramolecular architecture on the magnetic properties of a Dy^III single-molecule magnet: an ab initio investigation

• Julie Jung,
• Olivier Cador,
• Kevin Bernot,
• Fabrice Pointillart,
• Javier Luzon and
• Boris Le Guennic

Beilstein J. Nanotechnol. 2014, 5, 2267–2274, doi:10.3762/bjnano.5.236

• “core-shell” picture, where the core is the magnetic ion and the shell its organic surrounding, shell deformation upon grafting can drastically impact the properties of the molecule. A good example is Tb-phthalocyanine molecule, which is one of the most efficient SMM [30]. Depending on the surface and

Hybrid spin-crossover nanostructures

• Carlos M. Quintero,
• Gautier Félix,
• Iurii Suleimanov,
• José Sánchez Costa,
• Gábor Molnár,
• Lionel Salmon,
• William Nicolazzi and
• Azzedine Bousseksou

Beilstein J. Nanotechnol. 2014, 5, 2230–2239, doi:10.3762/bjnano.5.232

• unprecedented capabilities. Keywords: core–shell particle; multifunctionality; nanomaterials; spin-crossover; Review Introduction More than 15 years ago, Olivier Kahn highlighted the great potential of the so-called spin-crossover (SCO) materials on the nanoscale [1]. Indeed, there are interesting fundamental

• activity recently appeared in the literature and are examined according to a simple classification based on the position of the active SCO species on the core–shell nanostructure. One can thus envision a case in which the switchable active species is placed at the core, a second type where the active

• species is at the shell, and finally, a third type where both the core and the shell substructures are active (see Figure 1). To our knowledge, for the first type, only three examples have been reported. Raza et al. [20] produced core–shell nanostructures based on a Hofmann-type clathrate SCO core with

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

• : (i) biopolymers as controlling agents of nucleation and growth of inorganic materials; (ii) biopolymers as supports, either as molecular supports or as carrier particles acting as cores of core–shell structures; and (iii) so-called “soft templates”, which include on one hand stabilized droplets

• microparticles through a microgel route and coated them with silica to obtain core–shell composites. In an alternative method, spray-drying of biopolymer and biopolymer/silica solutions was conducted. Magnetic cobalt silicate could be also generated by introducing a cobalt salt during the process. C. Biopolymers

Effects of surface functionalization on the adsorption of human serum albumin onto nanoparticles – a fluorescence correlation spectroscopy study

• Pauline Maffre,
• Stefan Brandholt,
• Karin Nienhaus,
• Li Shang,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2014, 5, 2036–2047, doi:10.3762/bjnano.5.212

• measure the binding of various proteins. In the present study, we focus on a single protein, again HSA, and explore the change in protein binding onto CdSe/ZnS core–shell QDs with different surface functionalities. These NPs were water-solubilized with small thiolated ligands, leading to thin coatings

Data-adaptive image-denoising for detecting and quantifying nanoparticle entry in mucosal tissues through intravital 2-photon microscopy

• Torsten Bölke,
• Lisa Krapf,
• Regina Orzekowsky-Schroeder,
• Tobias Vossmeyer,
• Jelena Dimitrijevic,
• Horst Weller,
• Anna Schüth,
• Antje Klinger,
• Gereon Hüttmann and
• Andreas Gebert

Beilstein J. Nanotechnol. 2014, 5, 2016–2025, doi:10.3762/bjnano.5.210

• /ZnS-core/shell/shell quantum dots (QDs) used in this study were provided by the Center for Applied Nanotechnology, CAN GmbH, Germany (CANdots, Series A). These nanocrystals are originally dispersed in a nonpolar organic solvent. To allow for bioapplications they were transferred into the aqueous phase