Two step formation of metal aggregates by surface X-ray radiolysis under Langmuir monolayers: 2D followed by 3D growth

• Smita Mukherjee,
• Marie-Claude Fauré,
• Michel Goldmann and
• Philippe Fontaine

Beilstein J. Nanotechnol. 2015, 6, 2406–2411, doi:10.3762/bjnano.6.247

• -assembly properties of surfactant molecules in solution. By the choice of the organic molecule, we can tune the surface charge of the formed self-assembly in order to attract the ions in their vicinity. Therefore, we expect that during the irradiation process, the aggregation of the reduced atoms takes

Fabrication of hybrid graphene oxide/polyelectrolyte capsules by means of layer-by-layer assembly on erythrocyte cell templates

• Joseba Irigoyen,
• Nikolaos Politakos,
• Eleftheria Diamanti,
• Elena Rojas,
• Marco Marradi,
• Raquel Ledezma,
• Layza Arizmendi,
• J. Alberto Rodríguez,
• Ronald F. Ziolo and
• Sergio E. Moya

Beilstein J. Nanotechnol. 2015, 6, 2310–2318, doi:10.3762/bjnano.6.237

• lead to materials with properties more like G than GO [12][13][14][15]. The derivatization of G to form GO leads to easily dispersible and stable systems containing GO with an overall surface charge while exfoliated, for example, in water [16]. The use of GO sheets in the formation of hierarchical

• structures and assemblies is a subject of current interest, and if done by procedures involving wet chemical techniques, offers much potential for the development of advanced and composite layered materials. The assembly of GO in thin films on the basis of its surface charge can be accomplished using the

Electroviscous effect on fluid drag in a microchannel with large zeta potential

• Dalei Jing and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2015, 6, 2207–2216, doi:10.3762/bjnano.6.226

• /bjnano.6.226 Abstract The electroviscous effect has been widely studied to investigate the effect of surface charge-induced electric double layers (EDL) on the pressure-driven flow in a micro/nano channel. EDL has been reported to reduce the velocity of fluid flow and increase the fluid drag

• . Nevertheless, the study on the combined effect of EDL with large zeta potential up to several hundred millivolts and surface charge depenedent-slip on the micro/nano flow is still needed. In this paper, the nonlinear Poisson–Boltzmann equation for electrical potential and ion distribution in non-overlapping

• EDL is first analytically solved. Then, the modified Navier–Stokes equation for the flow considering the effect of surface charge on the electrical conductivity of the electrolyte and slip length is analytically solved. This analysis is used to study the effect of non-overlapping EDL with large zeta

Temperature-dependent breakdown of hydrogen peroxide-treated ZnO and TiO₂ nanoparticle agglomerates

• Sinan Sabuncu and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 1897–1903, doi:10.3762/bjnano.6.193

• Figure 1. As can be seen, both types of NPs are composed of NPs with a range of sizes. The average size of the ZnO and TiO2 NPs were 98 and 18 nm, respectively. Change in zeta potential after NP hydroxylation The zeta potential (ζ) of the NPs provides information about the surface charge of the particle

• in a solvent. The surface charge of a particle can vary with respect to the change in environment or any change in the surface chemistry. The proper treatment process of metal oxide NPs with H2O2 can reduce the activation energy of H2O2 resulting in the decomposition into H2O and O2, causing the

Predicting cytotoxicity of PAMAM dendrimers using molecular descriptors

• David E. Jones,
• Hamidreza Ghandehari and
• Julio C. Facelli

Beilstein J. Nanotechnol. 2015, 6, 1886–1896, doi:10.3762/bjnano.6.192

• . In spite of all the desirable properties of dendrimers, there is a significant setback for their use in biomedicine due to their potential toxicological effects, which depend on the structure that is used. It has been shown that cationic PAMAM dendrimers can have surface charge-, generation-, and

NanoE-Tox: New and in-depth database concerning ecotoxicity of nanomaterials

• Katre Juganson,
• Angela Ivask,
• Irina Blinova,
• Monika Mortimer and
• Anne Kahru

Beilstein J. Nanotechnol. 2015, 6, 1788–1804, doi:10.3762/bjnano.6.183

• ENMs generally include chemical composition, purity, primary particle size, shape, surface area, coating, agglomeration and/or aggregation, hydrodynamic size in the aqueous test medium, surface charge, stability and solubility of ENMs. For the current NanoE-Tox database (Supporting Information File 2

• environment the following information was registered: test medium, hydrodynamic size of NPs in the test environment (including the method used for analysis), dissolution (if applicable), and surface charge (ζ-potential). Concerning the toxicity testing, we tabulated the following information: test organism

• functionalised with different coatings, polyvinylpyrrolidone (PVP) and citrate being the most widely used. A parameter closely related to NP surface properties is surface charge. It has been shown that positively charged ENMs tend to attach to the cellular surface that is negatively charged and these

Template-controlled mineralization: Determining film granularity and structure by surface functionality patterns

• Nina J. Blumenstein,
• Jonathan Berson,
• Stefan Walheim,
• Petia Atanasova,
• Johannes Baier,
• Joachim Bill and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2015, 6, 1763–1768, doi:10.3762/bjnano.6.180

• agglomerates grow together (j–n) resulting in a rough surface for the final morphology. Deposition mechanism of mineralized ZnO nanoparticles on amino SAMs. The negative charges represent counterions attached to the positive surface charge (Stern layer) provided by protonated amino groups (–NH3

Synthesis, characterization and in vitro biocompatibility study of Au/TMC/Fe₃O₄ nanocomposites as a promising, nontoxic system for biomedical applications

• Hanieh Shirazi,
• Maryam Daneshpour,
• Soheila Kashanian and
• Kobra Omidfar

Beilstein J. Nanotechnol. 2015, 6, 1677–1689, doi:10.3762/bjnano.6.170

• , noble metals such as gold, or oxide layers such as silica or alumina) not only prevents their aggregation due to the change in surface charge, but also protects them from oxidation [12][20][21]. Additionally, proper surface coverage increases the stability and half-life of the magnetic nanoparticles

• , the final Au nanoparticles with a desirable diameter of 10 ± 2 nm (Figure 2a,b) and negative surface charge were obtained. The UV–vis absorption spectrum of a ruby-red colloidal solution of Au nanoparticles is presented in Figure 2c. Due to the excitation of surface plasmon vibrations, a strong peak

• nanoparticles is clearly visible in Figure 4a. The Fe3O4 nanoparticles are encapsulated by a contrasting layer of TMC, which inhibited aggregation due to the change in surface charge. In contrast, the polymer shell was not visibly recognizable in the TEM image of the chitosan/Fe3O4 nanoparticles (Figure 4c). It

The eNanoMapper database for nanomaterial safety information

• Nina Jeliazkova,
• Charalampos Chomenidis,
• Philip Doganis,
• Bengt Fadeel,
• Roland Grafström,
• Barry Hardy,
• Janna Hastings,
• Markus Hegi,
• Vedrin Jeliazkov,
• Nikolay Kochev,
• Pekka Kohonen,
• Cristian R. Munteanu,
• Haralambos Sarimveis,
• Bart Smeets,
• Pantelis Sopasakis,
• Georgia Tsiliki,
• David Vorgrimmler and
• Egon Willighagen

Beilstein J. Nanotechnol. 2015, 6, 1609–1634, doi:10.3762/bjnano.6.165

• distribution and zeta potentiometry to estimate the pH-dependent surface charge. Biological identity With the expanding insight into the factors determining toxicity, the list of measurable effects is growing increasingly long. The need for validated in vitro tests has been advocated since 2006 [1]. It is

Using natural language processing techniques to inform research on nanotechnology

• Nastassja A. Lewinski and
• Bridget T. McInnes

Beilstein J. Nanotechnol. 2015, 6, 1439–1449, doi:10.3762/bjnano.6.149

• , surface charge and molecular weight data beyond the core composition, which was fixed to PAMAM [15]. Incorporating almost 80% of the minimum characterization data, the NEIMiner appears to be the most comprehensive with regards to extraction of physico-chemical characterization properties. When assessing

Peptide-equipped tobacco mosaic virus templates for selective and controllable biomineral deposition

• Klara Altintoprak,
• Axel Seidenstücker,
• Alexander Welle,
• Sabine Eiben,
• Petia Atanasova,
• Nina Stitz,
• Alfred Plettl,
• Joachim Bill,
• Hartmut Gliemann,
• Holger Jeske,
• Dirk Rothenstein,
• Fania Geiger and
• Christina Wege

Beilstein J. Nanotechnol. 2015, 6, 1399–1412, doi:10.3762/bjnano.6.145

• outer TMV–CP surface charge and the introduction of specific amino acid motifs, guiding the nucleation and growth of mineral coatings around the TMV core. This is in analogy to natural biomineralization-directing protein domains identified for various organisms [55][56][57][58][59]. Direct genetic

Surface excitations in the modelling of electron transport for electron-beam-induced deposition experiments

• Francesc Salvat-Pujol,
• Roser Valentí and
• Wolfgang S. Werner

Beilstein J. Nanotechnol. 2015, 6, 1260–1267, doi:10.3762/bjnano.6.129

• features and trends of the surface excitation probability: Surface energy losses can be undergone by the charged projectile on either side of the interface, at the solid side or at the vacuum side. Indeed, a surface charge can be induced regardless of the side at which the projectile is moving on and, thus

Scanning reflection ion microscopy in a helium ion microscope

• Yuri V. Petrov and
• Oleg F. Vyvenko

Beilstein J. Nanotechnol. 2015, 6, 1125–1137, doi:10.3762/bjnano.6.114

• in the SE and in RI images, the origin of their mechanisms are quite different. Effect of a surface charge The RI image formation mechanisms described above originate from the ion scattering by the geometrical specimen relief and do not take into account the possible impact of surface charging

• , the influence of surface charge on their trajectories might not be negligible, and the question regarding possible image distortion arises. Under the action of the electric field of the positively charged sample surface, the trajectories of the primary ions become curved as schematically shown in

• accumulated surface charge plays te role of positive sample bias. The impact of the charging on the height of the surface steps is negligible. Conclusion In summary, we investigated the capabilities of a scanning reflection helium ion microscopy technique that was realized in a helium ion microscope for the

Superluminescence from an optically pumped molecular tunneling junction by injection of plasmon induced hot electrons

• Kai Braun,
• Xiao Wang,
• Andreas M. Kern,
• Hilmar Adler,
• Heiko Peisert,
• Thomas Chassé,
• Dai Zhang and
• Alfred J. Meixner

Beilstein J. Nanotechnol. 2015, 6, 1100–1106, doi:10.3762/bjnano.6.111

• the underlying sample Au surface is induced. It manifests itself as a highly localized surface charge oscillation at the very apex of the tip and the Au surface below and constitutes a laser-power dependent source of hot electrons that can recombine more efficiently with the hole in the junction

Protein corona – from molecular adsorption to physiological complexity

• Lennart Treuel,
• Dominic Docter,
• Michael Maskos and
• Roland H. Stauber

Beilstein J. Nanotechnol. 2015, 6, 857–873, doi:10.3762/bjnano.6.88

• and PBS buffer is below 1 nm, thus, smaller than the typical size of a protein (few nanometers). Further refining this idea in a different experimental approach, Treuel et al. chemically altered the surface charge distribution of HSA and studied the effect on the corona formation around dihydrolipoic

• the ε-amino group of lysine with succinic anhydride, Treuel et al. [4], turned these positively charged groups into negatively charged carboxylate functions, obtaining succinylated HSA (HSAsuc). In addition to the surface charge distribution, this succinylation changed the overall zeta potential of

• protein fold was preserved. They then used fluorescence correlation spectroscopy to measure binding curves for the adsorption of native and modified HSA to DHLA-coated QDs. Intriguingly, these relatively simple chemical modifications of the proteins surface charge distribution, were found to dramatically

In situ observation of biotite (001) surface dissolution at pH 1 and 9.5 by advanced optical microscopy

• Chiara Cappelli,
• Daniel Lamarca-Irisarri,
• Jordi Camas,
• F. Javier Huertas and
• Alexander E. S. Van Driessche

Beilstein J. Nanotechnol. 2015, 6, 665–673, doi:10.3762/bjnano.6.67

• aluminosilicate minerals (talc, phlogopite and saponite) could precipitate (SI > 0, Table 2). Although the derivation of the surface charge of multi-oxide silicates as a function of pH is complex and requires the knowledge of all zero point charge parameters (e.g., isoelectric point, point of zero net proton

• charge, point of zero salt effect) for an unambiguous description of biotite surface chemistry [48], in general, the alkali treatment of silicate mineral affects the variable surface charge in a way that reactivity towards charged and polar compounds should increase (increase in surface acidity) [49

Pulmonary surfactant augments cytotoxicity of silica nanoparticles: Studies on an in vitro air–blood barrier model

• Jennifer Y. Kasper,
• Lisa Feiden,
• Maria I. Hermanns,
• Christoph Bantz,
• Michael Maskos,
• Ronald E. Unger and
• C. James Kirkpatrick

Beilstein J. Nanotechnol. 2015, 6, 517–528, doi:10.3762/bjnano.6.54

• transfection and delivery studies using mainly cationic polymers or liposomes [8][24]. The positive NP surface charge enables better cellular contact and/or uptake than negatively charged or neutral molecules [25]. Nevertheless, the use of these positively charged drug and gene delivery carriers remains

• al., not only silica, but also ZnO, hollow silica-titania, and gold particles with a positive surface charge caused a higher cytotoxicity than the respective negative or uncharged NPs [24]. Likewise, carboxylic-modified silica nanoparticles, which have a negative surface charge, are of great interest

• by the manufacturer micromod GmbH). aSNP–NH2 retained a negative “netto” surface charge according to their zeta potential, although it is supposed to display a positive charge on the basis of the amino-groups. This phenomenon was already described by Tenzer et al., who concluded that according to the

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

• properties such as diameter and conformation variations due to dangling bonds, swelling, or surface charge variations from pH changes of the solution, are to a large extent unknown but can influence ion transport and the control of surface modification steps in a crucial manner. A homogeneous conformal

Biological responses to nanoscale particles

• Reinhard Zellner

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

• studies of nanoparticles) that the surface area seems to be one of the properties that causes a severe biological response, other properties such as solubility, hydrophobicity, surface functionalization, surface charge, colloidal stability and nanoparticle morphology have been suggested to be of equal

Dynamic force microscopy simulator (dForce): A tool for planning and understanding tapping and bimodal AFM experiments

• Horacio V. Guzman,
• Pablo D. Garcia and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 369–379, doi:10.3762/bjnano.6.36

• tip–surface charge density and σs is the sample surface charge density. Hertz contact mechanics The elastic contact between the tip and sample is usually modelled with the Hertz model [46] whereby for a spherical tip and a half-space sample the force is given by where δ is the indentation and Eeff is

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

• field of nanoparticles, many studies demonstrated a high impact of the shape, size and surface charge, which is determined by the functionalization, of nanoparticles on cell viability and internalization into cells. This work focused on the comparison of three different nanoparticle types to give a

• investigations revealed that the most important factors affecting cell viability and internalization by human cells are the type of metal (e.g., inorganic noble metal, metal oxide, semiconductor nanoparticles), the shape (e.g., rods, spheres, asymmetric assemblies) and the surface charge (negative, neutral or

• and nature of surface charge/coating [37]. In this context, a discrete size-dependency was observed, according to which larger particles seemed to be less cytotoxic than smaller ones [38][39][40][41][42]. In contrast, rather controversial findings have been reported in relation to the shape of gold

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

• effect of surface charge was also observed for random and organized motions of internalized particles in the cellular interior, with both the diffusion coefficient and the velocity increasing in the following order: CA–QDs, DHLA–QDs, DPA–QDs. This result could be attributed to a decrease of the vesicle

• DPA–QDs show minimal aggregation due to the low pKa value (4.73) of the DHLA carboxylic group [32] and the colloidal stability over a wide pH range of the zwitterionic coating, respectively [33]. In order to clarify whether the CA–QDs and DHLA–QDs affect the cells differently due to their surface

• charge or the aggregation rate (which reduces the effective concentration of single QDs in solution), we studied an alternative, carboxylated, MPA-coated preparation, which is only partially deprotonated at pH 7.4. We found that independent of the type and concentration of CdSe/ZnS QDs, the MDCKII cells

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

• general (positively or negatively) show a much more efficient adsorption of these proteins needed for the recognition by macrophages [33][34]. Other cell types follow the endocytotic process, which can be receptor mediated or unspecific. For the uptake via endocytosis a positive surface charge has shown

• indicates, that the functional groups embedded on the outer part of the micelle do not interact significantly with the surface of the inorganic NP. In contrast, the surface charge was influenced by the end-group of the polymer as it was expected. This could be proven by zeta potential measurements in

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• dark-field microscopy together with transmission electron microscopy to quantify the uptake of gold nanoparticles into MDCK II cells as a function of shape, stabilizing agent, and surface charge [25]. We found that CTAB-coated particles are easily accumulated within cells, while PEG coatings inhibit

Caveolin-1 and CDC42 mediated endocytosis of silica-coated iron oxide nanoparticles in HeLa cells

• Nils Bohmer and
• Andreas Jordan

Beilstein J. Nanotechnol. 2015, 6, 167–176, doi:10.3762/bjnano.6.16

• and surface charge, were tested in HeLa cells as a model cell line. To elucidate, which molecular pathways are involved in their endocytosis, well-known endocytotic mechanisms [26][27][28] were inhibited by specific knockdown of key proteins via siRNA (Figure 1). Experimental Superparamagnetic iron

• ). These modifications resulted in different physicochemical properties referring to SPIONs surface charge and their size distribution under physiological conditions (Table 1). The primary particle size was determined by transmission electron microscopy (EM906, Zeiss). The zeta potential and the average

• . Fluorescent silica coated iron oxide nanoparticles (SCIONs) SCIONs were provided and characterized by the National Institute of Health (Maryland, USA). They were monodisperse at pH 7 and had a hydrodynamic diameter of 17 nm with a surface charge of 50 ± 5 mV. For detection in confocal fluorescence microscopy