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

The impact of the confinement of reactants on the metal distribution in bimetallic nanoparticles synthesized in reverse micelles

• Concha Tojo,
• Elena González and
• Nuria Vila-Romeu

Beilstein J. Nanotechnol. 2014, 5, 1966–1979, doi:10.3762/bjnano.5.206

• than the other, it will form the core. The metal which is reduced more slowly will be deposited onto this core, forming the outer layers, which results in a core–shell nanostructure. In contrast, a small difference between reduction rates of the two metals leads to an alloy. Third, this result was

• within a nanoparticle can be observed in Figure 1, which shows the structures obtained by the simulation. When the quantities of the metal salts are equal (see Figure 1a, 50% Au), the nanoparticle shows a core–shell structure due to the difference in reduction rates (vAu = 10∙vPt). Most particles have a

• homogeneous and composed of Au. From the maximum, Pt and the remaining Au are deposited on the core, giving rise to the middle mixed layers. In this case, a pure Pt shell is formed when the Au is exhausted. This is the case shown in Figure 3b, which corresponds to the core–shell structure obtained using 50

Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

• Pravin Kumar,
• Udai Bhan Singh,
• Kedar Mal,
• Sunil Ojha,
• Indra Sulania,
• Dinakar Kanjilal,
• Dinesh Singh and
• Vidya Nand Singh

Beilstein J. Nanotechnol. 2014, 5, 1864–1872, doi:10.3762/bjnano.5.197

• performance, Pt NPs are used in fabricating super capacitors [35]. The Pt NPs in core–shell structures (Pt forms the shell) are used in surface enhanced Raman scattering (SERS) studies [36] as well. Moreover, Pt is relatively inert in atmosphere and ex situ characterization of irradiated samples can also be

Carbon-based smart nanomaterials in biomedicine and neuroengineering

• Antonina M. Monaco and
• Michele Giugliano

Beilstein J. Nanotechnol. 2014, 5, 1849–1863, doi:10.3762/bjnano.5.196

• -like explosives under oxygen-deprived conditions, are core–shell like particles with a diameter of 2–8 nm. Their structure consists of an sp3-hybridised core surrounded by layers of amorphous and sp2-hybridised carbon [10][11][12], and they show a strong tendency to agglomerate [13] in clusters with

Room temperature, ppb-level NO₂ gas sensing of multiple-networked ZnSe nanowire sensors under UV illumination

• Sunghoon Park,
• Soohyun Kim,
• Wan In Lee,
• Kyoung-Kook Kim and
• Chongmu Lee

Beilstein J. Nanotechnol. 2014, 5, 1836–1841, doi:10.3762/bjnano.5.194

• catalysts, core–shell structure formation [19][20][21] and UV irradiation [22][23][24] have been developed to improve the sensing performance, detection limit and selectivity of 1D nanostructure sensors at room temperature. Among these techniques, the UV illumination method was used in the present study to

Mechanical properties of sol–gel derived SiO₂ nanotubes

• Boris Polyakov,
• Mikk Antsov,
• Sergei Vlassov,
• Leonid M Dorogin,
• Mikk Vahtrus,
• Roberts Zabels,
• Sven Lange and
• Rünno Lõhmus

Beilstein J. Nanotechnol. 2014, 5, 1808–1814, doi:10.3762/bjnano.5.191

• moduli of SiO2 NTs measured by different methods were compared and discussed. Keywords: atomic force microscopy (AFM); nanomechanical tests; scanning electron microscopy (SEM); silica nanotubes; Introduction Hybrid silica core–shell and empty-shell nanomaterials were intensively investigated in recent

• ). The problem of indentation of thick-walled elastic NTs was addressed and discussed. To the best of our knowledge, no in situ SEM bending tests, as well as AFM nanoindentation experiments were performed on sol–gel silica NTs previously. Experimental Ag/SiO2 core–shell NWs were synthesized by coating Ag

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• electrons and holes [21]. They are therefore likely to degrade the optical yield. On the other hand, shallower states like those produced at the Si/SiO2 core–shell interface of oxidized Si NCs are most likely to shift the absorption/emission spectra with respect to pristine NCs [54]. Inclusion of many-body

The surface properties of nanoparticles determine the agglomeration state and the size of the particles under physiological conditions

• Christoph Bantz,
• Olga Koshkina,
• Thomas Lang,
• Hans-Joachim Galla,
• C. James Kirkpatrick,
• Roland H. Stauber and
• Michael Maskos

Beilstein J. Nanotechnol. 2014, 5, 1774–1786, doi:10.3762/bjnano.5.188

• condensation of silicic acid esters (mostly tetraethyl orthosilicate, TEOS) under basic alcoholic conditions. It was first described by W. Stöber in 1968 [60] and gives well defined particles with sizes of around 20 to 5,000 nm. Numerous improvements allow for the synthesis of core–shell particles, of dye

• , different crosslinking densities can be realized and the formation of systems with core–shell architecture is possible. By introducing monomers with functional groups, each of the structural elements (core, shell or one of multiple shells) can be functionalized independently [66][67][68]. The addition of a

• inhalation toxicology. The preparation of the poly(organosiloxane) particles that we report on is based on previously described syntheses by our group [66][69]. These procedures were extended as follows [75]: First, core–shell particles with a dye-labelled core were synthesized by using the basic synthesis

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

• . These include high hydrophilicity, easy introduction of functional comonomers by copolymerization and the possibility to control both the molecular weight and the thickness of the shell. PDMAAm-coated γ-Fe2O3 particles seem to be thus a perspective basis of advanced core–shell architectures, e.g., for

On the structure of grain/interphase boundaries and interfaces

• K. Anantha Padmanabhan and
• Herbert Gleiter

Beilstein J. Nanotechnol. 2014, 5, 1603–1615, doi:10.3762/bjnano.5.172

• ferromagnetism in Fe90Sc10 nano-glasses, which in the melt-spun and crystalline states is paramagnetic [15]. In fact even as-prepared nano-glassy powders of metallic materials do not have a core–shell structure (not more than a monolayer in any case) and exhibit a Mössbauer spectrum similar to that of the melt

Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays

• Christoph Rehbock,
• Jurij Jakobi,
• Lisa Gamrad,
• Selina van der Meer,
• Daniela Tiedemann,
• Ulrike Taylor,
• Wilfried Kues,
• Detlef Rath and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165

• . This often favors element segregation and the formation of core shell structures in the resulting nanoparticles [137][138]. Laser-based synthesis methods have proven to be a veritable alternative to generate AuAg alloy nanoparticles with homogeneous elemental distributions even on a single particle

• colloidal mixtures inducing an alloying process [29][143][144], which was reported to occur via core-shell intermediates [145]. Another approach entails ablation of silver targets in the presence of gold nanoparticles [146]. Post-irradiation method proofs to be highly flexible as to the composition of the

The cell-type specific uptake of polymer-coated or micelle-embedded QDs and SPIOs does not provoke an acute pro-inflammatory response in the liver

• Markus Heine,
• Alexander Bartelt,
• Oliver T. Bruns,
• Denise Bargheer,
• Artur Giemsa,
• Barbara Freund,
• Ludger Scheja,
• Christian Waurisch,
• Alexander Eychmüller,
• Rudolph Reimer,
• Horst Weller,
• Peter Nielsen and
• Joerg Heeren

Beilstein J. Nanotechnol. 2014, 5, 1432–1440, doi:10.3762/bjnano.5.155

• of cadmium-containing nanocrystals, pathological alterations in response to the injection of CdSe–ZnS core–shell QDs were observed only in some of these studies [9][11], while others found ultrastructural changes in the kidneys [10] or the spleen [12]. These results are surprising taking into account

Liquid fuel cells

• Grigorii L. Soloveichik

Beilstein J. Nanotechnol. 2014, 5, 1399–1418, doi:10.3762/bjnano.5.153

• reaction (HOR) and oxygen reduction reaction (ORR), but it is very expensive. To reduce the Pt loading and therefore the cost for the electrocatalyst, Pt-containing alloys and structured nanoparticles, e.g., “core–shell” materials with less expensive metals are being investigated. Alkaline fuel cells are

Synthesis, characterization, and growth simulations of Cu–Pt bimetallic nanoclusters

• Subarna Khanal,
• Ana Spitale,
• Nabraj Bhattarai,
• Daniel Bahena,
• J. Jesus Velazquez-Salazar,
• Sergio Mejía-Rosales,
• Marcelo M. Mariscal and
• Miguel José-Yacaman

Beilstein J. Nanotechnol. 2014, 5, 1371–1379, doi:10.3762/bjnano.5.150

• optics, magnetism, catalysis, and others, mainly because their high tunability and superior features compared with those of their monometallic counterparts [1][2][3][4][5][6]. Depending on the elements, relative concentrations, and details of the synthesis method, the BM may form core–shell structures

• -like structures for the Cu–Pt system, and core–shell structures for Au–Pt and Ag–Pt. Yu et al. [35] investigated the formation of and dealloying of CuPt bimetallic nanoparticles in presence of hexadecylamine or PVP as capping agents, obtaining different morphologies of nanoparticles depending on their

• sizes. Recently, several groups have worked on the synthesis of CuPt core–shell and alloys nanoparticles, obtaining morphologies such as nanotubes, cubes, spheres, hollow structures and others [36][37][38][39]. These particles exhibit excellent catalytic activities for CO oxidation, methanol oxidation

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• that lose energy by exciting the core-shell electrons in the specimen. Because the energy levels in the core-shells are unique for every element, the core-loss signals can be used as a fingerprint of the elements present in the specimen, with a much higher energy resolution than energy dispersive X-ray

• (EDX) analysis. The core-shell excitation process is localized around the atoms, and hence atomic-resolution chemical mappings can be achieved by using EELS core-loss signals combined with a sub-nanometer sized electron probe [43][44][45][46][47]. For example, by using EELS at a low acceleration

Optimizing the synthesis of CdS/ZnS core/shell semiconductor nanocrystals for bioimaging applications

• Li-wei Liu,
• Si-yi Hu,
• Ying Pan,
• Jia-qi Zhang,
• Yue-shu Feng and
• Xi-he Zhang

Beilstein J. Nanotechnol. 2014, 5, 919–926, doi:10.3762/bjnano.5.105

• luminescence-intensity CdS/ZnS core/shell QDs are suitable for optoelectronic devices and some biological applications [29][30][31][32]. Although CdS/ZnS QDs have been proposed for the use in biological applications, no research was so far reported on their biomedical applications. Our research has developed a

• core/shell-structured QDs are desirable due to their strongly enhanced quantum yield (QY). We also tested the QY of three samples based on Equation 1: Here, Φ and ΦS are the QYs for the sample and the standard, I (sample) and IS (standard) are the integrated emission peak areas, A (sample) and AS

• core/shell structured QDs showed high QYs, outstanding physical and chemical stability, this strongly enhanced QY could be attributed to the wide band gap ZnS shell providing surface trap states that enhance the photostability. Photostability test Photobleaching is an effective method for improving the

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

• /Fe3O4 nanoparticles are roughly spherical with a core/shell structure (Figure 2). The mean core diameter is 12 nm, and the shell thickness is 2 nm. HRTEM indicate that each Fe/Fe3O4 nanoparticle assumes polycrystalline structure with rigid edges. TEM images (Figure 3) of recycled catalyst after 10 runs