Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• modifications. The OM–NaYF4:Yb3+/Er3+ nanoparticles (50 mg) were dispersed in cyclohexane (10 mL). Igepal CO-520 (0.5 mL) and 25% aqueous ammonia (0.08 mL) were added, and the suspension was mixed using a Sonopuls sonicator (Bandelin, Berlin, Germany) for 30 min, yielding a stable colloid. TMOS (0.04 mL) was

Electrochemical behavior of polypyrrol/AuNP composites deposited by different electrochemical methods: sensing properties towards catechol

• Celia García-Hernández,
• Cristina García-Cabezón,
• Cristina Medina-Plaza,
• Fernando Martín-Pedrosa,
• Yolanda Blanco,
• José Antonio de Saja and
• María Luz Rodríguez-Méndez

Beilstein J. Nanotechnol. 2015, 6, 2052–2061, doi:10.3762/bjnano.6.209

• of films deposited onto SS or Pt were almost identical. The average size of the AuNPs was between 30 and 40 nm (regardless of the method used), which is consistent with the absorbance at 540 nm observed by colloid that was used to obtain the nanocomposites by trapping. The number of AuNPs

• on a hot plate, then 1 mL of solution (2) was quickly added to the HAuCl4 solution while stirring. The mixture was then boiled for 20 min. Using this procedure, a red colloid with a UV absorbance maximum at λ = 540 nm was obtained. Instruments Electropolymerizations and electrochemical studies were

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

• synthesized, Au nanoparticle, colloid solution for about 2 h under continuous stirring conditions. The Au nanoparticles were assumed to attach to the polymer/Fe3O4 complex via electrostatic interaction, which was confirmed by the discoloration of the mixture. After washing with deionized water and adding

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

• , Gebauer, Treuel and co-workers [53] presented an in-depth investigation of the quantitative effect of corona formation on colloidal stability. By carefully increasing the ionic strength of the surrounding medium, Gebauer et al. [53] removed the charge stabilization of a citrate-coated Ag colloid, and

• revealed a decrease of the collision efficiency (i.e., the overall number of collisions divided by the number of collisions that form an agglomerate) with an increasing protein (human serum albumin, HSA) concentration (Figure 1a). Intriguingly, they found that their colloid was stable at a point where

• the deliberately destabilized colloid. Black dots: data points, black solid line: Hill fit to the data points (KD = 71 ± 17 nmol·L−1, n = 2.71) indicating a cooperative binding behavior. Reproduced with permission from [53]. Copyright 2012 American Chemical Society. (a): Schematic representation of

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

• capability to investigate cryogenic samples in the HZB-TXM, the electronic structure of individual hybrid colloid particles in their hydrated environment were analysed [63]. Here, the structural homogeneity of nanoparticles in the hybrid particle was examined. Nanoscale valence changes in resistive switching

• magnetic nanoparticles which will have future applications in photo thermal therapy or drug delivery can be optimized by different analysis methods including NEXAFS spectroscopy with the HZB-TXM [65]. In the latter case as well as in the case of hybrid colloid particles the nanoparticles have sizes below

Raman spectroscopy as a tool to investigate the structure and electronic properties of carbon-atom wires

• Alberto Milani,
• Matteo Tommasini,
• Valeria Russo,
• Andrea Li Bassi,
• Andrea Lucotti,
• Franco Cataldo and
• Carlo S. Casari

Beilstein J. Nanotechnol. 2015, 6, 480–491, doi:10.3762/bjnano.6.49

• from NIR (1064 nm) to blue (458 nm) wavelengths, illustrating that this is not a resonance-activated effect [39]. When interacting with metal nanoparticles in solution, H-terminated polyynes promote colloid aggregation, which causes the plasmon resonance to broaden and shift from the visible to the NIR

Exploring plasmonic coupling in hole-cap arrays

• Thomas M. Schmidt,
• Maj Frederiksen,
• Vladimir Bochenkov and
• Duncan S. Sutherland

Beilstein J. Nanotechnol. 2015, 6, 1–10, doi:10.3762/bjnano.6.1

• heating the particles to temperatures close to and above the glass transition of polystyrene to allow reshaping of the colloid giving increased wetting of the silica surface and thereby reducing the vertical distance between the caps and holes. Any coupling between caps and hole arrays should be strongly

Intake of silica nanoparticles by giant lipid vesicles: influence of particle size and thermodynamic membrane state

• Florian G. Strobl,
• Florian Seitz,
• Christoph Westerhausen,
• Armin Reller,
• Adriano A. Torrano,
• Christoph Bräuchle,
• Achim Wixforth and
• Matthias F. Schneider

Beilstein J. Nanotechnol. 2014, 5, 2468–2478, doi:10.3762/bjnano.5.256

• . Mechanical aspects of such a colloid–membrane interaction are treated by several theoretical models. A simple, purely mechanical picture of such an interaction involves at least three mechanical parameters: the adhesion energy per unit area gad, the bending stiffness of the membrane κ and its surface tension

Nanobioarchitectures based on chlorophyll photopigment, artificial lipid bilayers and carbon nanotubes

• Marcela Elisabeta Barbinta-Patrascu,
• Stefan Marian Iordache,
• Ana Maria Iordache,
• Nicoleta Badea and
• Camelia Ungureanu

Beilstein J. Nanotechnol. 2014, 5, 2316–2325, doi:10.3762/bjnano.5.240

• research stage with the design, preparation and characterization techniques needed for monitoring these biomaterials, and presents new interdisciplinary aspects involving concepts of biochemistry, biophysics, microbiology, nanotechnology, colloid and supramolecular chemistry, and materials science. The

Coating with luminal gut-constituents alters adherence of nanoparticles to intestinal epithelial cells

• Heike Sinnecker,
• Katrin Ramaker and
• Andreas Frey

Beilstein J. Nanotechnol. 2014, 5, 2308–2315, doi:10.3762/bjnano.5.239

• increasing colloid stability or camouflaging attachment sites, certain components of intestinal fluid are capable to modify particle surfaces in such a way that interactions with cellular surface structures result in an increased binding. Keywords: adherence; agglomeration; intestinal epithelial cells

• ], and possible implications for the particle–cell interactions are considered. For example, it was shown that human serum albumin (HSA), BSA and fetal bovine serum can build a protein corona around NPs whereby the particles are stabilized against agglomeration and the colloid stability of the particle

• be visible at the magnification used during light microscopy. The proteins BSA and casein seem to diminish the contact of NPs with the cell surface by enhancing the NP colloid stability. This effect is particularly evident in software-processed microscope images of 100 nm particles on Caco-2 cells

Influence of stabilising agents and pH on the size of SnO₂ nanoparticles

• Olga Rac,
• Patrycja Suchorska-Woźniak,
• Marta Fiedot and
• Helena Teterycz

Beilstein J. Nanotechnol. 2014, 5, 2192–2201, doi:10.3762/bjnano.5.228

• precipitation reaction in a solution of standard composition (see Experimental section), a colloid was obtained. This was observed in the UV–vis spectrum of which a characteristic peak at a wavelength of 282 nm distinguishes the presence of tin dioxide particles in solution (Figure 1). The standard composition

• 30 min. Before the measurement, a gold layer was deposited on the sample using a coater (Edwards–Pirani 501). UV–vis spectrum of a tin dioxide colloid stabilised with PEI. DLS results of the diameter distribution of the resulting nanoparticles formed in a solution with a standard composition. XRD

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

• , micelles, and vesicles, and on the other hand continuous scaffolds generated by gelling biopolymers. Keywords: biomacromolecules; biopolymer; colloid; nanoparticle; organic–inorganic hybrid; template; Introduction During the natural synthesis of inorganic matter in living organisms, referred to as

PVP-coated, negatively charged silver nanoparticles: A multi-center study of their physicochemical characteristics, cell culture and in vivo experiments

• Sebastian Ahlberg,
• Alexandra Antonopulos,
• Jörg Diendorf,
• Ralf Dringen,
• Matthias Epple,
• Rebekka Flöck,
• Wolfgang Goedecke,
• Christina Graf,
• Nadine Haberl,
• Jens Helmlinger,
• Fabian Herzog,
• Frederike Heuer,
• Stephanie Hirn,
• Christian Johannes,
• Stefanie Kittler,
• Manfred Köller,
• Katrin Korn,
• Wolfgang G. Kreyling,
• Fritz Krombach,
• Jürgen Lademann,
• Kateryna Loza,
• Eva M. Luther,
• Marcelina Malissek,
• Martina C. Meinke,
• Daniel Nordmeyer,
• Anne Pailliart,
• Jörg Raabe,
• Fiorenza Rancan,
• Barbara Rothen-Rutishauser,
• Eckart Rühl,
• Carsten Schleh,
• Andreas Seibel,
• Christina Sengstock,
• Lennart Treuel,
• Annika Vogt,
• Katrin Weber and
• Reinhard Zellner

Beilstein J. Nanotechnol. 2014, 5, 1944–1965, doi:10.3762/bjnano.5.205

• zeta potential of −20 mV and a metallic core diameter of about 70 nm. All concentrations given refer to the amount of silver. This review article summarizes the results of all groups who participated in this study. Synthesis and colloid-chemical characterization of silver nanoparticles The synthesis of

• , which is indicative for a monodisperse system. The particles were negatively charged with a zetapotential of −20 mV. These particles were used in all described experiments after thorough chemical and colloid-chemical characterization. Dissolution of dispersed silver nanoparticles Silver nanoparticles

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

• physiological salinity, zeta potential determinations based on electrophoretic mobility measurements should be treated with great care. As they are influenced by a multitude of factors, such as surface charge, salinity and by the interactions that are present in the colloid, the applied models to derive zeta

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

• by sodium hypochlorite and the coating with D-mannose and poly(N,N-dimethylacrylamide) according to earlier reports [20][25]. While coating with D-mannose was performed by the slow addition of D-mannose solution to the γ-Fe2O3 colloid, coating with PDMAAm included solution radical polymerization of N

• serum for 24 h and a series of aqueous γ-Fe2O3 colloids were added to reach concentrations of 100, 50, 25, 12.5 and 6 µL colloid per mL of fresh cultural medium. The cells were grown with the nanoparticles for 72 h until a confluent monolayer of the cells was obtained. Consequently, 15 μL of MTT dye (5

• control and all of them revealed cytotoxic activity. At the same time, the data confirmed the tendency of decreasing particle cytotoxicity if coated with PDMAAm or D-mannose. The strongest cytotoxic effect was observed at the highest concentration of the colloid (100 µL/mL of medium). The PDMAAm-coated γ

Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

• Priscilla Vasthi Quintana-Ramirez,
• Ma. Concepción Arenas-Arrocena,
• José Santos-Cruz,
• Marina Vega-González,
• Omar Martínez-Alvarez,
• Víctor Manuel Castaño-Meneses,
• Laura Susana Acosta-Torres and
• Javier de la Fuente-Hernández

Beilstein J. Nanotechnol. 2014, 5, 1542–1552, doi:10.3762/bjnano.5.166

• cells. Experimental Crystalline copper sulfide nanostructures were obtained by one-pot synthesis in an organic solvent while raising the reaction temperature from 220 to 260 °C. Amorphous copper sulfide was also synthesized by a chemical reaction in aqueous solution at 40 °C. Films, colloid and powder

Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer

• Ulrich C. Fischer,
• Carsten Hentschel,
• Florian Fontein,
• Linda Stegemann,
• Christiane Hoeppener,
• Harald Fuchs and
• Stefanie Hoeppener

Beilstein J. Nanotechnol. 2014, 5, 1441–1449, doi:10.3762/bjnano.5.156

• highly localized shadow. The removal of the gold mask reveals the SAM nanopattern. Keywords: colloid lithography; contact lithography; near-field; photochemistry; self-assembled silane monolayers; Introduction Chemical nanopatterns consist of spatially separated areas providing different chemically

Surface processes during purification of InP quantum dots

• Natalia Mordvinova,
• Pavel Emelin,
• Alexander Vinokurov,
• Sergey Dorofeev,
• Artem Abakumov and
• Tatiana Kuznetsova

Beilstein J. Nanotechnol. 2014, 5, 1220–1225, doi:10.3762/bjnano.5.135

• from byproducts. There are a lot of strategies for the size and shape-selective purification of nanoparticles [7]. Size-selective precipitation is one of the most important separation technique used widely in colloid chemistry. It relies on the fractional precipitation from a “good” solvent by addition

Nanodiamond-DGEA peptide conjugates for enhanced delivery of doxorubicin to prostate cancer

• Amanee D Salaam,
• Patrick Hwang,
• Roberus McIntosh,
• Hadiyah N Green,
• Ho-Wook Jun and
• Derrick Dean

Beilstein J. Nanotechnol. 2014, 5, 937–945, doi:10.3762/bjnano.5.107

• shown in Scheme 1. With this technique, EDAC was used to activate carboxylic groups on the ND surface. Sulfo-NHS was used to form a stable amide bond between the –COOH groups on the NDs and the free NH2 groups on DGEA. Briefly, 200 µL of ND colloid (5 mg/mL in distilled water) was added with 100 µL of

Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

• Claudio Davet Gutiérrez-Lazos,
• Mauricio Ortega-López,
• Manuel A. Pérez-Guzmán,
• A. Mauricio Espinoza-Rivas,
• Francisco Solís-Pomar,
• Rebeca Ortega-Amaya,
• L. Gerardo Silva-Vidaurri,
• Virginia C. Castro-Peña and
• Eduardo Pérez-Tijerina

Beilstein J. Nanotechnol. 2014, 5, 881–886, doi:10.3762/bjnano.5.100

• distribution for our samples. Nevertheless the exciton peak disappeared once the CdTe colloid was drop-cast on the glass substrates Figure 5 shows the absorbance spectra of CdTe-NC of the colloidal solution and of a liquid sample processed by the size-separation technique. The effect of size-separation can be

• observed by considering the maximum absorption peak. The excitonic peak is narrower than that the of the colloid and nearly symmetric, similar to a nearly monodispersed sample. Additionally, the maximum absorbance has shifted from 607 nm to 589 nm arguing for a lower size dispersion of the CdTe-NC. However

• , this result imposes a technological limitation in the colloid application in a thin-film device due to strong stabilization of oleic acid, which is nonconductive and separates the nanocrystals with spacings of about 0.7 nm and thus impedes their electrical contact [15]. Conclusion Oleic acid-stabilized

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

• , 0.1 M sodium citrate (13 mL) was added under sonication, and the magnetite was oxidized by slow addition of 5% sodium hypochlorite solution (10 mL) to yield maghemite (γ-Fe2O3). The above described washing procedure was repeated with the resulting primary colloid, which was finally passed through a

• Millex HV syringe filter (0.45 µm membrane, 33 mm in diameter). Coating of colloidal iron oxide nanoparticles was achieved by the post-synthesis method [12]. Aqueous D-mannose (2 mL; concentration 128 mg/mL) was added dropwise under sonication to a portion of primary colloid containing 44 mg of iron

One-step synthesis of high quality kesterite Cu₂ZnSnS₄ nanocrystals – a hydrothermal approach

• Vincent Tiing Tiong,
• John Bell and
• Hongxia Wang

Beilstein J. Nanotechnol. 2014, 5, 438–446, doi:10.3762/bjnano.5.51

• are observed. The above results demonstrate that high concentration of TGA is not favourable for the formation of monodisperse CZTS nanocrystals. At a high concentration, TGA might form a colloid which wraps a certain surface of CZTS particles, inhibiting the growth of crystals in all directions [25

Preparation of poly(N-vinylpyrrolidone)-stabilized ZnO colloid nanoparticles

• Tatyana Gutul,
• Emil Rusu,
• Nadejda Condur,
• Veaceslav Ursaki,
• Evgenii Goncearenco and
• Paulina Vlazan

Beilstein J. Nanotechnol. 2014, 5, 402–406, doi:10.3762/bjnano.5.47

• instance, a nano-colloid has been synthesized using a top-down wet chemistry method with bulk ZnO powder with grain size of 1–2 mm as starting material [9]. Stearic or oleic acids have been used as capping agents in the stabilization technique to prevent agglomeration of the ZnO nanoparticles [9][10][11

Photoactivation of luminescence in CdS nanocrystals

• Valentyn Smyntyna,
• Bogdan Semenenko,
• Valentyna Skobeeva and
• Nikolay Malushin

Beilstein J. Nanotechnol. 2014, 5, 355–359, doi:10.3762/bjnano.5.40

• cadmium sulfide nanocrystals (NCs) synthesized by colloid chemistry in a gelatinous matrix. The photostimulation of the short-wavelength emission band with λmax = 480 nm has been detected. It is shown that the determining factor of the photostimulation effect is the adsorption of the water molecules on

• nanocrystals used in these experiments were prepared by colloid chemistry of solutions of cadmium- and sulfursalts in an aqueous gelatin solution. Details of the sample preparation are described in [15]. The average radius of the cadmium sulfide nanocrystals was calculated from the optical absorption spectra

Design criteria for stable Pt/C fuel cell catalysts

• Josef C. Meier,
• Carolina Galeano,
• Ioannis Katsounaros,
• Jonathon Witte,
• Hans J. Bongard,
• Angel A. Topalov,
• Claudio Baldizzone,
• Stefano Mezzavilla,
• Ferdi Schüth and
• Karl J. J. Mayrhofer

Beilstein J. Nanotechnol. 2014, 5, 44–67, doi:10.3762/bjnano.5.5

• ], nanohorns [29], ordered mesoporous carbons (OMCs) [30][31], carbon aerogels [32], carbon shells [33][34][35][36], colloid-imprinted carbon supports (CIC) [37] and even boron-doped diamond structures [38][39]. Alternatively, certain non-carbon materials (e.g., oxides, carbides and nitrides of metals such as