Institute of Particle Technology

Erlangen, Germany

Institute of Particle Technology

Erlangen, Germany
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Qazi T.H.,Charité - Medical University of Berlin | Hafeez S.,Universitatsmedizin BerlinBerlin13353 Germany | Schmidt J.,Institute of Particle Technology | Duda G.N.,Charité - Medical University of Berlin | And 2 more authors.
Journal of Biomedical Materials Research - Part A | Year: 2017

Bioactive glasses (BAGs) are highly interesting materials for bone regeneration applications in orthopedic and dental defects. It is quite well known that ionic release from BAGs influences cell behavior and function. Mindful of the clinical scenario, we hypothesized that local cell populations might additionally physically interact with the implanted BAG particles and respond differently than to just the ionic stimuli. We therefore studied the biological effect of two BAG types (45S5 and 1393) applied to human mesenchymal stromal cells (hMSCs) in three distinct presentation modes: (a) direct contact; and to dissolution products in (b) 2D, and (c) 3D culture. We furthermore investigated how the dose-dependence of these BAG particles, in concentrations ranging from 0.1 to 2.5 w/v %, influenced hMSC metabolic activity, proliferation, and cell spreading. These cellular functions were significantly hampered when hMSCs were exposed to high concentrations of either glasses, but the effects were more pronounced in the 45S5 groups and when the cells were in direct contact with the BAGs. Furthermore the biological effect of 1393 BAG outperformed that of 45S5 BAG in all tested presentation modes. These outcomes highlight the importance of investigating cell-BAG interactions in experimental set-ups that recapitulate host cell interactions with BAG particles. © 2017 Wiley Periodicals, Inc.


Gasparotto L.H.S.,Institute of Particle Technology | Prowald A.,EFZN Goslar | Borisenko N.,Institute of Particle Technology | El Abedin S.Z.,Institute of Particle Technology | And 3 more authors.
Journal of Power Sources | Year: 2011

In the present study macroporous aluminium electrodes were made by template assisted electrodeposition from ionic liquids. Polystyrene (PS) spheres (diameter 600 nm) were applied onto polished copper electrodes by immersion into an alcoholic suspension containing PS spheres. Al was deposited from the chloroaluminate ionic liquid [EMIm]Cl/AlCl3 (40/60 mol.%) on this substrate. After chemical dissolution of the PS spheres a macroporous aluminium electrode was obtained which served as a host material for Li deposition from ionic liquids. Lithium deposition in this matrix is reversible showing certain activation with an increasing number of cycles. After 10 cycles of Li deposition/dissolution the macroporous structure is still visible. © 2010 Elsevier B.V. All rights reserved.


Bao H.,Institute of Particle Technology | Bihr T.,Institute of Theoretical Physics | Bihr T.,University of Stuttgart | Smith A.-S.,Institute of Theoretical Physics | Klupp Taylor R.N.,Institute of Particle Technology
Nanoscale | Year: 2014

Patchy particles comprise regions of differing material or chemical functionality on otherwise isotropic cores. To meet the great potential of these anisotropic structures in a wide range of application fields, completely new approaches are sought for the scalable and tunable production of patchy particles, particularly those with nanoscale dimensions. In this paper the synthesis of patchy particles via a simple colloidal route is investigated. Using surfactant-free cationic polystyrene nanospheres as core particles, gold patches are produced through the in situ reduction of chloroauric acid with ascorbic acid. The fact that such nanostructured metal patches can be heterogeneously nucleated on polymer nanospheres is related to the electrostatic interaction between core and metal precursor. Furthermore, the lateral expansion of the gold patches over the polystyrene surface is facilitated by an excess of ascorbic acid. The morphology of the patches is highly dendritic and process-induced variations in the structure are related to gold surface mobility using Monte Carlo simulations based on the diffusion limited aggregation principle. Considering the pH dependent behaviour of ascorbic acid it is possible to predict the moiety which most likely adsorbs to the polymer surface and promotes gold surface diffusion. This enables the judicious adjustment of the pH to also obtain non-dendritic patches. On account of the plasmonic behaviour of gold, the patchy particles have morphology-dependent optical properties. The systematic development of the synthetic approach described here is expected to lay a foundation for the development of functional materials based on the self- or directed-assembly of nanoscale building blocks with anisotropic interactions and properties. © the Partner Organisations 2014.


Al Zoubi M.,Institute of Particle Technology | Al-Salman R.,Institute of Particle Technology | El Abedin S.Z.,Institute of Particle Technology | El Abedin S.Z.,National Research Center of Egypt | And 2 more authors.
ChemPhysChem | Year: 2011

The electrochemical synthesis of gallium nanostructures in an ionic liquid is presented. Gallium nanowires and macroporous structures were synthesized by the template-assisted electrodeposition in the ionic liquid 1-butyl-1- methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py1,4]TFSA) containing GaCl3 as the precursor. Track-etched polycarbonate membranes with an average pore diameter of 90 nm and a thickness of 21 μm were used as templates for the nanowire synthesis. Ga nanowires with a length of more than 4 μm and an average diameter corresponding to that of the template's pores were easily obtained by this method. Macroporous structures with an average pore diameter of 600 nm were obtained by the electrochemical deposition of Ga inside polystyrene colloidal crystal templates and the subsequent removal of the template by THF. The macroporous deposit showed a granular morphology with smallest grain sizes of about 40 nm and light reflections. The nanostructures of Ga were characterized by HR-SEM and EDX analysis. Ga get it! The electrochemical synthesis of gallium nanostructures by template-assisted electrodeposition in an ionic liquid is presented. The picture shows photographs of a sample of macroporous Ga (600 nm pore size) displaying different colors due to light reflections upon changing the angle of incident white light. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bao H.,Institute of Particle Technology | Peukert W.,Institute of Particle Technology | Taylor R.N.K.,Institute of Particle Technology
Advanced Materials | Year: 2011

The one-pot synthesis of patchy particles with morphologically tunable optical properties by the heterogeneous nucleation and growth of silver onto colloidal silica particles is described. Heat treatment of the silica and coating reaction conditions can be optimized in order to produce full yields of patchy particles. Dissolution of the cores leads to stable silver cages. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Distaso M.,Institute of Particle Technology | Mackovic M.,Center for Nanoanalysis and Electronic Microscopy | Spiecker E.,Center for Nanoanalysis and Electronic Microscopy | Peukert W.,Institute of Particle Technology
Chemistry - A European Journal | Year: 2014

By using ZnO as a model system, the formation of twinned nanostructures has been investigated under microwave irradiation, exploiting experimental conditions ranging from purely solvothermal when N,N-dimethylformamide was used, to purely hydrothermal when water was the solvent. A progressive increase in size, elongation and roughness of the surface was observed with increasing water content in the solvent mixture. Particular attention was paid to the reactivity of the ZnO surfaces towards dissolution. Our results show that the formation of twinned nanorods is a dynamic process and that the coupling interphase itself is highly reactive. Consequently, the twinned rods undergo a number of complex dissolution processes that are responsible for the appearance of a wide distribution of defects either on the surface or inside the structure. Poly(N-vinyl pyrrolidone) influences the photoluminescent properties of the as-synthesised materials and allows control of the ratio of the intensity of the UV and visible emission. Split at the seam cut! By increasing the water content of N,N-dimethylformamide reaction mixtures, the growth of anisotropic twinned ZnO nanostructures is achieved, characterised by the presence of a seam cut (see figure). Defect formation and surface dissolution occur, especially at the seam cut. The emission from defects is effectively quenched by using poly(vinyl pyrrolidone) during the synthesis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Endres F.,Institute of Particle Technology | Hofft O.,Institute of Particle Technology | Borisenko N.,Institute of Particle Technology | Gasparotto L.H.,Institute of Particle Technology | And 6 more authors.
Physical Chemistry Chemical Physics | Year: 2010

In this discussion paper we discuss our recent results on the electrodeposition of materials and in situ STM/AFM measurements which demonstrate that ionic liquids should not be regarded as neutral solvents which all have similar properties. In particular, we focus on differences in interfacial structure (solvation layers) on metal electrodes as a function of ionic liquid species. Recent theoretical and experimental results show that conventional double layers do not form on metal electrodes in ionic liquid systems. Rather, a multilayer architecture is present, with the number of layers determined by the ionic liquid species and the properties of the surface; up to seven discrete interfacial solvent layers are present on electrode surfaces, consequently there is no simple electrochemical double layer. Both the electrodeposition of aluminium and of tantalum are strongly influenced by ionic liquids: in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide, [Py1,4]TFSA, aluminium is obtained as a nanomaterial, whereas in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, [EMIm]TFSA, a microcrystalline material is made. Tantalum can be deposited from [Py 1,4]TFSA, whereas from [EMIm]TFSA only non-stoichiometric tantalum fluorides TaFx are obtained. It is likely that solvation layers influence these reactions. © 2010 the Owner Societies.


Prowald A.,EFZN Energieforschungszentrum Goslar | El Abedin S.Z.,Institute of Particle Technology | El Abedin S.Z.,National Research Center of Egypt | Borisenko N.,Institute of Particle Technology | Endres F.,Institute of Particle Technology
Zeitschrift fur Physikalische Chemie | Year: 2012

One challenge in the use of metallic lithium in secondary lithium ion or lithium air batteries is the dendritic growth of lithium upon repeated cycling which might either lead to a short circuit or at least to an uneven current distribution and bad cycling stability. In the present paper we present our first results on the electrodeposition of lithium from an ionic liquid within the voids of a polystyrene opal structure on copper. For this purpose polystyrene spheres with an average diameter of about 600 nm were applied onto a copper sheet by a simple dipping process resulting in a layer thickness of about 10 μm. Lithium can be deposited within this polymer structure without damaging it and the subsequent dissolution of the polystyrene spheres delivers a macroporous lithium film, proving that a mechanically stable composite electrode is feasible. © by Oldenbourg Wissenschaftsverlag, München.


Gunther A.,Institute of Particle Technology | Wirth K.-E.,Institute of Particle Technology
International Journal of Heat and Mass Transfer | Year: 2013

Applying the process of superheated atomization (flash atomization) finely dispersed sprays with moderate droplet velocities can be obtained, without the necessity of high pressure or an additional gas phase. In this paper occurring evaporation phenomena inside a nozzle capillary and their impact on the generated spray are analyzed. Evaporation is enhanced for increasing superheating. An intensified evaporation induces a considerably extended spray and smaller droplet sizes are generated. Furthermore a reduced mass flux and decreased velocity of the droplets are to be expected. By increasing the amount of vapor spray pulsation, triggered by bubble bursting, is increased. This is shown in acoustic measurements, which also demonstrate a simple way to monitor, or even control the atomization of superheated liquids. © 2013 Elsevier Ltd. All rights reserved.


Distaso M.,Institute of Particle Technology | MacKovic M.,Center for Nanoanalysis and Electronic Microscopy | Spiecker E.,Center for Nanoanalysis and Electronic Microscopy | Peukert W.,Institute of Particle Technology
Chemistry - A European Journal | Year: 2012

Let's become twins! Early stages of formation of twin ZnO nanorods under microwave irradiation have been studied. The coupling of facets with the same polarity was triggered by the rough surface and the defect-rich microstructure of the constituent ZnO building blocks. Oriented attachment was found to be the underlying mechanism of the twinning process (see scheme). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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