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

• cyanide gold NPs was performed and second, a cyano-bridged polymer shell was grown on the surface of the Au NPs by controlling the time of the reaction process. Following these procedures, two more remarkable processes were achieved: a second layer of PBA was inserted into the previous architecture in a

Properties of plasmonic arrays produced by pulsed-laser nanostructuring of thin Au films

• Katarzyna Grochowska,
• Katarzyna Siuzdak,
• Peter A. Atanasov,
• Carla Bittencourt,
• Anna Dikovska,
• Nikolay N. Nedyalkov and
• Gerard Śliwiński

Beilstein J. Nanotechnol. 2014, 5, 2102–2112, doi:10.3762/bjnano.5.219

• resonance positions which lie above the solid line which represents values calculated for the model, single and non-interacting Au NPs embedded in a medium of nm = 1.5. The experimental data fulfill the assumption that the nm value (in the case of supported NPs) is smaller than that of the embedded ones

• structures showing the SPR effect, Au NPs play important role in the construction of electrochemical sensors [55]. This is confirmed by numerous results obtained with the use of Au-modified, conducting oxide materials, such as indium tin oxide, fluorine tin oxide and others. In particular, the ITO substrate

• from the point of view of electrochemical properties. The preference is closely related to the presence of Au NPs having a larger size and lower inter-particle distances thus effectively covering the ITO surface as compared to Au-NP10, which is also revealed by the SEM inspection. For the selected

In vitro interaction of colloidal nanoparticles with mammalian cells: What have we learned thus far?

• Moritz Nazarenus,
• Qian Zhang,
• Mahmoud G. Soliman,
• Pablo del Pino,
• Beatriz Pelaz,
• Susana Carregal-Romero,
• Joanna Rejman,
• Barbara Rothen-Rutishauser,
• Martin J. D. Clift,
• Reinhard Zellner,
• G. Ulrich Nienhaus,
• James B. Delehanty,
• Igor L. Medintz and
• Wolfgang J. Parak

Beilstein J. Nanotechnol. 2014, 5, 1477–1490, doi:10.3762/bjnano.5.161

• metal NPs, in particular to Au NPs [125][126]. v) Proteins, in general, tend to adsorb to surfaces, which is also true on the nanometer scale. Adsorption of albumin is, for example, an integral part of opsonization [127][128]. The proteins adsorbed to the surface of NPs are typically termed protein

• ) agglomerated Au NPs. The scale bars correspond to 100 nm. Adopted with permission from [30]. Copyright 2014 Royal Society of Chemistry. Acknowledgements This work and a large fraction of quoted work by WJP were supported by the German Research Foundation (DFG, SPP 1313, Project PA794/4-2) and this review

Mimicking exposures to acute and lifetime concentrations of inhaled silver nanoparticles by two different in vitro approaches

• Fabian Herzog,
• Kateryna Loza,
• Sandor Balog,
• Martin J. D. Clift,
• Matthias Epple,
• Peter Gehr,
• Alke Petri-Fink and
• Barbara Rothen-Rutishauser

Beilstein J. Nanotechnol. 2014, 5, 1357–1370, doi:10.3762/bjnano.5.149

• our previous studies [42][44] to easily compare the effects of different materials such as gold and silver and furthermore to compare different sizes and coatings of Ag NPs. The previous results were obtained with 20 nm citrate-coated Ag NPs [44] and 15 nm citrate-coated Au NPs [42]. In the present

• study we used the ALICE system to nebulize well-characterized [45][46] PVP-capped 100 nm Ag NPs. The majority of the 100 nm PVP-capped Ag NPs were found as aggregates inside vesicles, a finding which was similar for the 20 nm Ag NPs [44]. The aggregation was not as prominent for 15 nm Au NPs [42], and

• release of IL-8 is in contrast to any other studies we performed with all NPs at the ALI (i.e., Au NPs and also Ag NPs of different sizes), as an immune response could never be monitored with ELISA. To compare the different approach of submerged vs ALI exposures it is important to relate any observed

Purification of ethanol for highly sensitive self-assembly experiments

• Kathrin Barbe,
• Martin Kind,
• Christian Pfeiffer and
• Andreas Terfort

Beilstein J. Nanotechnol. 2014, 5, 1254–1260, doi:10.3762/bjnano.5.139

• pure, powdered zeolite. The color of these beads changed from off-white to yellow after immersion into the HAuCl4 solution and to violet upon pyrolysis in the tube furnace, indicative for the formation of the Au-NPs with their characteristic Mie scattering behavior [38]. Typical samples of zeolite

• stem from the pyrolytic deposition of the Au-NPs (2 HAuCl4 → 2 Au + 3 Cl2 + 2 HCl), the ethanol had to be distilled before use, also helpful for removing tiny zeolite particles floating in the ethanol. It turned out to be advantageous to apply a sub-boiling setup instead of a regular still to eliminate

• , this procedure had to be carried out a second time using freshly regenerated zeolite-supported Au-NPs to obtain fully purified solvent. Thin film sensors for chemisorption measurements Following the protocol of Bohn et al. [29][32], thin gold films were produced by physical vapor deposition of gold

Manipulation of nanoparticles of different shapes inside a scanning electron microscope

• Boris Polyakov,
• Sergei Vlassov,
• Leonid M. Dorogin,
• Jelena Butikova,
• Mikk Antsov,
• Sven Oras,
• Rünno Lõhmus and
• Ilmar Kink

Beilstein J. Nanotechnol. 2014, 5, 133–140, doi:10.3762/bjnano.5.13

• studies of metal NPs. The forces needed to overcome static friction and move individual polyhedron-like Au and sphere-like Ag NPs on an oxidized Si surface are measured and analyzed with respect to the morphology of the NPs. Experimental The 150 nm Au NPs (BBI International) were deposited from solution

• and friction. The NPs used in the present experiments exhibited various morphologies, which need to be considered in more detail. Intact Au NPs deposited on a substrate have well distinguishable facets (Figure 2a) and will be referred to as polyhedron-like. Tetrahedral, decahedral, icosahedral and

• other shapes can be identified in the SEM image (Figure 2b). Some particles exhibit truncated edges and apexes. Typical morphologies of Au NPs are listed in Table 1. It should be noted, that after the removal of the surfactant by thermal treatment partial rounding of the particles might occur [20]. The

Synthesis of embedded Au nanostructures by ion irradiation: influence of ion induced viscous flow and sputtering

• Udai B. Singh,
• D. C. Agarwal,
• S. A. Khan,
• S. Mohapatra,
• H. Amekura,
• D. P. Datta,
• Ajay Kumar,
• R. K. Choudhury,
• T. K. Chan,
• Thomas Osipowicz and
• D. K. Avasthi

Beilstein J. Nanotechnol. 2014, 5, 105–110, doi:10.3762/bjnano.5.10

• formation of Au NPs embedded in the glass substrates by the 50 keV Si− ion irradiation of irregularly shaped Au nanostructures on the glass surfaces at a fluence of 3 × 1016 ions/cm2. The depth profiles of Au in the samples were obtained from high-resolution Rutherford backscattering spectrometry studies

• . The results from TRIDYN simulation reveal the role of various ion-induced processes during the synthesis of the embedded Au NPs, viz. sputtering and recoiling atoms. Simulation and experimental results suggest that the viscous flow is one of the major factors that are responsible for the embedding of

• for the synthesis of embedded Au NPs in a silica matrix [12][13][14][15][16]. Ion implantation is one of the standard ways for the synthesis of noble metal NPs embedded in a matrix and offers the control over the depth distribution of the NPs by properly adjusting the parameters of the ion beam such

Cyclic photochemical re-growth of gold nanoparticles: Overcoming the mask-erosion limit during reactive ion etching on the nanoscale

• Burcin Özdemir,
• Axel Seidenstücker,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2013, 4, 886–894, doi:10.3762/bjnano.4.100

• etching and, consequently, the achievable pillar height is strongly restricted. The present work presents approaches on how to get around both problems. For this purpose, arrays of Au NPs (starting diameter 12 nm) are deposited on top of silica substrates by applying diblock copolymer micelle

• homogeneously dispensed. The controlled seed growth of Au NPs was established under UV-irradiation (Osram Hg lamp; exposure wavelengths: 365 and 390 nm) provided by a mask aligner (Karl SUSS MJB 3 Mask UV 400). Afterwards, the substrates were subsequently cleaned in acetone and isopropanol and dried with

Controlled positioning of nanoparticles on a micrometer scale

• Fabian Enderle,
• Oliver Dubbers,
• Alfred Plettl and
• Paul Ziemann

Beilstein J. Nanotechnol. 2012, 3, 773–777, doi:10.3762/bjnano.3.86

• arranged in arrays of a certain geometry. For this purpose, a method is introduced combining the bottom-up self-organization of precursor-loaded micelles providing Au nanoparticles (NPs), with top-down electron-beam lithography. As an example, 13 nm Au NPs are arranged in a square array with interparticle

• distances of some tens of nanometers creative ideas have been realized based on even three-dimensional DNA spacers linked to Au NPs [23]. Somewhat more flexible with respect to the type of NPs is their positioning, exploiting wettability contrast of a substrate previously prepared by, e.g., microcontact

• additionally allows a broad variation of geometries for the finally arranged NPs. Results and Discussion Preparation of Au nanoparticles (NPs) The starting point of the present approach is the fabrication of hexagonally arranged Au NPs applying a previously reported recipe based on the self-organization of

Plasmonics-based detection of H₂ and CO: discrimination between reducing gases facilitated by material control

• Gnanaprakash Dharmalingam,
• Nicholas A. Joy,
• Benjamin Grisafe and
• Michael A. Carpenter

Beilstein J. Nanotechnol. 2012, 3, 712–721, doi:10.3762/bjnano.3.81

• and the use of both temperature changes as well as physical and chemical filters [19]. Another example in the direction of materials development is the work by Buso et al., who monitored specific wavelengths of the absorption spectrum of SiO2 sol–gel films containing NiO and Au NPs during gas

• NPs. One of the motivations of this work was to examine if the catalytic activity of the sol–gel-coated Au NPs increased due to the reduction in temperature-driven sintering of the Au NPs by the metal-oxide films, which would serve to reduce the Au NP size. They showed that such an arrangement had a

• overcoat has a crucial role in restricting the growth of the Au NPs during long-term high-temperature exposures, and its thickness has a direct impact on the number of oxygen vacancies in the film. The vacancies are introduced into the film through the yttria dopant in zirconia. YSZ is an excellent oxygen

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• (~280 nm at 4000 rpm) and typical TiO2 crystallites of 10–20 nm. The observation of very small Au NPs agrees well with earlier findings for DP prepared Au/TiO2 catalysts, which generally yielded Au NPs with small sizes and a relatively uniform particle-size distribution [35]. Based on the TEM analysis

• on highly dispersed Au/TiO2 catalysts, which also showed no significant growth of the Au NPs during reaction with similar pretreatment and reaction conditions/procedures [36][37][38]. Note that the size distribution of the Au nanoparticles differs significantly in the thin anatase films (280 nm

• thickness) compared to on the dispersed TiO2 supports with approximately spherical TiO2 particles of about 10–20 nm in diameter [33][39]. Despite the fact that we used the same preparation procedure for the Au deposition and formation of Au NPs on the TiO2 film as on the dispersed TiO2 support, the Au

Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

• Samer Darwich,
• Karine Mougin,
• Akshata Rao,
• Enrico Gnecco,
• Shrisudersan Jayaraman and
• Hamidou Haidara

Beilstein J. Nanotechnol. 2011, 2, 85–98, doi:10.3762/bjnano.2.10

• described in the Experimental section. “As-synthesized” Au NPs, meaning NPs covered with citrate stabilizing group (COO−), referred to as “reference NPs” were deposited onto bare and hydrophobized (CH3-terminated coating) silicon wafers, and manipulated using AFM in tapping mode. During manipulation, the

• the environmental conditions, manipulation of nanoparticles on a surface requires that they are loosely attached in order to be able to move them. The decrease of relative humidity from 53 down to 33% has a strong impact on the mobility of the hydrophilic Au NPs. Above RH = 43%, the adsorbed Au

• system. However, this process does not affect strongly the mobility of hydrophobic Au NPs. They move whatever the environment. This difference can be explained by the existence and the local shape of a liquid condensate (Scheme 2 and Scheme 3) around the tip–substrate contact [47]. In a humid environment

Flash laser annealing for controlling size and shape of magnetic alloy nanoparticles

• Damien Alloyeau,
• Christian Ricolleau,
• Cyril Langlois,
• Yann Le Bouar and
• Annick Loiseau

Beilstein J. Nanotechnol. 2010, 1, 55–59, doi:10.3762/bjnano.1.7

• NPs [19] and spherical shape is the energetically favourable configuration. Evidence of NPs melting has been also reported for irradiated Au NPs [15][30]. Bulk CoPt alloy has a phase transition at 825 °C between the L10 ordered structure at low temperature and the disordered FCC structure at high

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• the finally obtained spatial arrangement of the NPs. This basic idea of preparation and the different steps involved are summarized in the schematics shown in Scheme 1. The first experimental realization of the above approach was demonstrated by the preparation of hexagonally ordered arrays of Au NPs