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Beilstein Journal of Nanotechnology

Morten Willatzen, Lok C Lew Yan Voon, Appala Naidu Gandi, Udo Schwingenschlögl
A general three-dimensional continuum model of phonons in two-dimensional materials is developed. Our first-principles derivation includes full consideration of the lattice anisotropy and flexural modes perpendicular to the layers and can thus be applied to any two-dimensional material. In this paper, we use the model to not only compare the phonon spectra among the group-IV materials but also to study whether these phonons differ from those of a compound material such as molybdenum disulfide. The origin of quadratic modes is clarified...
2017: Beilstein Journal of Nanotechnology
Dario Rocca, Ali Abboud, Ganapathy Vaitheeswaran, Sébastien Lebègue
Phosphorene has recently attracted significant interest for applications in electronics and optoelectronics. Inspired by this material an ab initio study was carried out on new two-dimensional binary materials with a structure analogous to phosphorene. Specifically, carbon and silicon monochalcogenides have been considered. After structural optimization, a series of binary compounds were found to be dynamically stable in a phosphorene-like geometry: CS, CSe, CTe, SiO, SiS, SiSe, and SiTe. The electronic properties of these monolayers were determined using density functional theory...
2017: Beilstein Journal of Nanotechnology
Bertha T Pérez-Martínez, Lorena Farías-Cepeda, Víctor M Ovando-Medina, José M Asua, Lucero Rosales-Marines, Radmila Tomovska
Film forming, stable hybrid latexes made of methyl metacrylate (MMA), butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA) copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs) were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (Tg and insoluble polymer fraction)...
2017: Beilstein Journal of Nanotechnology
Christoph Göbel, Ottokar Klimm, Florian Puchtler, Sabine Rosenfeldt, Stephan Förster, Birgit Weber
Spin-crossover compounds are a class of materials that can change their spin state from high spin (HS) to low spin (LS) by external stimuli such as light, pressure or temperature. Applications demand compounds with defined properties concerning the size and switchability that are maintained when the compound is integrated into composite materials. Here, we report the synthesis of [Fe(Leq)(Lax)]n coordination polymer (CP) nanoparticles using self-assembled polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer (BCP) micelles as template...
2017: Beilstein Journal of Nanotechnology
Kati Erdmann, Jessica Ringel, Silke Hampel, Manfred P Wirth, Susanne Fuessel
We have previously shown that carbon nanofibers (CNFs) and carbon nanotubes (CNTs) can sensitize prostate cancer (PCa) cells to platinum-based chemotherapeutics. In order to further verify this concept and to avoid a bias, the present study investigates the chemosensitizing potential of CNFs and CNTs to the conventional chemotherapeutics docetaxel (DTX) and mitomycin C (MMC), which have different molecular structures and mechanisms of action than platinum-based chemotherapeutics. DU-145 PCa cells were treated with DTX and MMC alone or in combination with the carbon nanomaterials...
2017: Beilstein Journal of Nanotechnology
Jin Zhang, Yibing Cai, Xuebin Hou, Xiaofei Song, Pengfei Lv, Huimin Zhou, Qufu Wei
Titanium dioxide (TiO2) nanofibers have been widely applied in various fields including photocatalysis, energy storage and solar cells due to the advantages of low cost, high abundance and nontoxicity. However, the low conductivity of ions and bulk electrons hinder its rapid development in lithium-ion batteries (LIB). In order to improve the electrochemical performances of TiO2 nanomaterials as anode for LIB, hierarchically porous TiO2 nanofibers with different tetrabutyl titanate (TBT)/paraffin oil ratios were prepared as anode for LIB via a versatile single-nozzle microemulsion electrospinning (ME-ES) method followed by calcining...
2017: Beilstein Journal of Nanotechnology
Isabella Tavernaro, Christian Cavelius, Henrike Peuschel, Annette Kraegeloh
In recent years, fluorescent nanomaterials have gained high relevance in biological applications as probes for various fluorescence-based spectroscopy and imaging techniques. Among these materials, dye-doped silica nanoparticles have demonstrated a high potential to overcome the limitations presented by conventional organic dyes such as high photobleaching, low stability and limited fluorescence intensity. In the present work we describe an effective approach for the preparation of fluorescent silica nanoparticles in the size range between 15 and 80 nm based on L-arginine-controlled hydrolysis of tetraethoxysilane in a biphasic cyclohexane-water system...
2017: Beilstein Journal of Nanotechnology
Vineeth Kumar Bandari, Lakshmi Varadharajan, Longqian Xu, Abdur Rehman Jalil, Mirunalini Devarajulu, Pablo F Siles, Feng Zhu, Oliver G Schmidt
The investigation of charge transport in organic nanocrystals is essential to understand nanoscale physical properties of organic systems and the development of novel organic nanodevices. In this work, we fabricate organic nanocrystal diodes contacted by rolled-up robust nanomembranes. The organic nanocrystals consist of vanadyl phthalocyanine and copper hexadecafluorophthalocyanine heterojunctions. The temperature dependent charge transport through organic nanocrystals was investigated to reveal the transport properties of ohmic and space-charge-limited current under different conditions, for instance, temperature and bias...
2017: Beilstein Journal of Nanotechnology
Yuriy Y Smolin, Masoud Soroush, Kenneth K S Lau
Polyaniline (PANI) is synthesized via oxidative chemical vapor deposition (oCVD) using aniline as monomer and antimony pentachloride as oxidant. Microscopy and spectroscopy indicate that oCVD processing conditions influence the PANI film chemistry, oxidation, and doping level. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) indicate that a substrate temperature of 90 °C is needed to minimize the formation of oligomers during polymerization...
2017: Beilstein Journal of Nanotechnology
Urszula Klekotka, Magdalena Rogowska, Dariusz Satuła, Beata Kalska-Szostko
Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11-16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with -COOH and -NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker...
2017: Beilstein Journal of Nanotechnology
Meike Koenig, Joerg Lahann
In recent years much work has been conducted in order to create patterned and structured polymer coatings using vapor deposition techniques - not only via post-deposition treatment, but also directly during the deposition process. Two-dimensional and three-dimensional structures can be achieved via various vapor deposition strategies, for instance, using masks, exploiting surface properties that lead to spatially selective deposition, via the use of additional porogens or by employing oblique angle polymerization deposition...
2017: Beilstein Journal of Nanotechnology
Jennifer E Francis, David Mason, Raphaël Lévy
Semiconductor quantum dots (Qdots) have been utilised as probes in fluorescence microscopy and provide an alternative to fluorescent dyes and fluorescent proteins due to their brightness, photostability, and the possibility to excite different Qdots with a single wavelength. In spite of these attractive properties, their implemenation by biologists has been somewhat limited and only a few Qdot conjugates are commercially available for the labelling of cellular targets. Although many protocols have been reported for the specific labelling of proteins with Qdots, the majority of these relied on Qdot-conjugated antibodies synthesised specifically by the authors (and therefore not widely available), which limits the scope of applications and complicates replication...
2017: Beilstein Journal of Nanotechnology
Carlos Angulo Barrios, Víctor Canalejas-Tejero
We report on a top-down method for the controlled fabrication of three-dimensional (3D), closed, thin-shelled, hollow nanostructures (nanocages) on planar supports. The presented approach is based on conventional microelectronic fabrication processes and exploits the permeability of thin metal films to hollow-out polymer-filled metal nanocages through an oxygen-plasma process. The technique is used for fabricating arrays of cylindrical nanocages made of thin Al shells on silicon substrates. This hollow metal configuration features optical resonance as revealed by spectral reflectance measurements and numerical simulations...
2017: Beilstein Journal of Nanotechnology
Liga Saulite, Dominyka Dapkute, Karlis Pleiko, Ineta Popena, Simona Steponkiene, Ricardas Rotomskis, Una Riekstina
Nanotechnology-based drug design offers new possibilities for the use of nanoparticles in imaging and targeted therapy of tumours. Due to their tumour-homing ability, nano-engineered mesenchymal stem cells (MSCs) could be utilized as vectors to deliver diagnostic and therapeutic nanoparticles into a tumour. In the present study, uptake and functional effects of carboxyl-coated quantum dots QD655 were studied in human skin MSCs. The effect of QD on MSCs was examined using a cell viability assay, Ki67 expression analysis, and tri-lineage differentiation assay...
2017: Beilstein Journal of Nanotechnology
Dario Zappa, Angela Bertuna, Elisabetta Comini, Navpreet Kaur, Nicola Poli, Veronica Sberveglieri, Giorgio Sberveglieri
Preparation and characterization of different metal oxide (NiO, WO3, ZnO, SnO2 and Nb2O5) nanostructures for chemical sensing are presented. p-Type (NiO) and n-type (WO3, SnO2, ZnO and Nb2O5) metal oxide nanostructures were grown on alumina substrates using evaporation-condensation, thermal oxidation and hydrothermal techniques. Surface morphologies and crystal structures were investigated through scanning electron microscopy and Raman spectroscopy. Furthermore, different batches of sensors have been prepared, and their sensing performances towards carbon monoxide and nitrogen dioxide have been explored...
2017: Beilstein Journal of Nanotechnology
Rasha K Al-Shewiki, Carola Mende, Roy Buschbeck, Pablo F Siles, Oliver G Schmidt, Tobias Rüffer, Heinrich Lang
Subsequent treatment of H2TPP(CO2H)4 (tetra(p-carboxylic acid phenyl)porphyrin, 1) with an excess of oxalyl chloride and HNR2 afforded H2TPP(C(O)NR2)4 (R = Me, 2; iPr, 3) with yields exceeding 80%. The porphyrins 2 and 3 could be converted to the corresponding metalloporphyrins MTPP(C(O)NR2)4 (R = Me/iPr for M = Zn (2a, 3a); Cu (2b, 3b); Ni (2c, 3c); Co (2d, 3d)) by the addition of 3 equiv of anhydrous MCl2 (M = Zn, Cu, Ni, Co) to dimethylformamide solutions of 2 and 3 at elevated temperatures. Metalloporphyrins 2a-d and 3a-d were obtained in yields exceeding 60% and have been, as well as 2 and 3, characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS) and IR and UV-vis spectroscopy...
2017: Beilstein Journal of Nanotechnology
Mohamed Hassoun, Iwan W Schie, Tatiana Tolstik, Sarmiza E Stanca, Christoph Krafft, Juergen Popp
The throughput of spontaneous Raman spectroscopy for cell identification applications is limited to the range of one cell per second because of the relatively low sensitivity. Surface-enhanced Raman scattering (SERS) is a widespread way to amplify the intensity of Raman signals by several orders of magnitude and, consequently, to improve the sensitivity and throughput. SERS protocols using immuno-functionalized nanoparticles turned out to be challenging for cell identification because they require complex preparation procedures...
2017: Beilstein Journal of Nanotechnology
Rafał Babilas, Dariusz Łukowiec, Laszlo Temleitner
The structure of a multicomponent metallic glass, Mg65Cu20Y10Ni5, was investigated by the combined methods of neutron diffraction (ND), reverse Monte Carlo modeling (RMC) and high-resolution transmission electron microscopy (HRTEM). The RMC method, based on the results of ND measurements, was used to develop a realistic structure model of a quaternary alloy in a glassy state. The calculated model consists of a random packing structure of atoms in which some ordered regions can be indicated. The amorphous structure was also described by peak values of partial pair correlation functions and coordination numbers, which illustrated some types of cluster packing...
2017: Beilstein Journal of Nanotechnology
Govinda Lakhotiya, Sonal Bajaj, Arpan Kumar Nayak, Debabrata Pradhan, Pradip Tekade, Abhimanyu Rana
We report enhanced catalytic activity of CuO nanopetals synthesized by microwave-assisted wet chemical synthesis. The catalytic reaction of CuO nanopetals and H2O2 was studied with the application of external light source and also under dark conditions for the degradation of the hazardous dye methylene blue. The CuO nanopetals showed significant catalytic activity for the fast degradation of methylene blue and rhodamine B (RhB) under dark conditions, without the application of an external light source. This increased catalytic activity was attributed to the co-operative role of H2O2 and the large specific surface area (≈40 m(2)·g(-1)) of the nanopetals...
2017: Beilstein Journal of Nanotechnology
Pavel Aleksandrovich Kotin, Sergey Sergeevich Bubenov, Natalia Evgenievna Mordvinova, Sergey Gennadievich Dorofeev
We report the synthesis of colloidal CdSe quantum dots doped with a novel Ag precursor: AgCl. The addition of AgCl causes dramatic changes in the morphology of synthesized nanocrystals from spherical nanoparticles to tetrapods and finally to large ellipsoidal nanoparticles. Ellipsoidal nanoparticles possess an intensive near-IR photoluminescence ranging up to 0.9 eV (ca. 1400 nm). In this article, we explain the reasons for the formation of the ellipsoidal nanoparticles as well as the peculiarities of the process...
2017: Beilstein Journal of Nanotechnology
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